JP2009068689A - Wet friction material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely obtain a further significant drag torque reduction effect even in the case of a specification where lubricating oil is not supplied from an inner peripheral side or in the case where a stirring torque increases by occurrence of oil accumulation in an outer periphery, in a wet friction material. <P>SOLUTION: In the case of the specification where the lubricating oil (ATF) is not supplied from the inner peripheral side of this wet friction material (without shaft center lubrication), that is, in the case where the lubricating oil is supplied only from the outer peripheral side of the wet friction material, by executing rounding work or chamfering work to either or both of corner portions of the outer periphery of segment pieces 3, 3A, 3B and 3C in the case of segment-type friction materials 1, 1A and 1C, a high drag torque reduction effect can be provided by a peeling effect where the ATF runs from the working portion into front surfaces of the segment pieces 3, 3A, 3B and 3C and intrudes between a counterpart material and them. Even in the case where the lubricating oil (ATF) is supplied from the inner peripheral side, a high drag torque reduction effect can be provided because the stirring torque resulting from the ATF in the outer peripheral portion can be suppressed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a wet friction material that obtains torque by applying high pressure to the opposite surface in a state immersed in oil, and a friction material base material cut into segment pieces on a flat plate ring-shaped metal core on both sides Or a segment type friction material bonded to one side, or a flat ring-shaped cored bar, or both sides or one side of a ring-shaped friction material with a ring-shaped friction material base bonded to one side are pressed or cut to give a radius The present invention relates to a ring type friction material formed with a plurality of oil grooves in the direction.

  In recent years, as a wet friction material, a friction material that has been cut into segment pieces along a flat ring shape on a flat ring metal core with the aim of reducing costs by improving material yield and reducing fuel consumption in vehicles by reducing drag torque A segment type friction material has been developed, in which the base material is sequentially aligned with an adhesive at intervals to become oil grooves and bonded over the entire circumference, and the friction material base material cut into segment pieces is also bonded to the back surface. ing. Such a segment type friction material is a friction material engagement provided with a plurality or a single friction plate used in an automatic transmission (hereinafter abbreviated as “AT”) such as an automobile or a transmission such as a motorcycle. It can be used for devices.

  As an example, wet hydraulic clutches are used in automatic transmissions for automobiles, etc., and multiple segment type friction materials and multiple separator plates are alternately stacked, and torque is transmitted by pressure-contacting both plates with hydraulic pressure. In order to absorb frictional heat generated when shifting from the non-fastened state to the fastened state and to prevent wear of the friction material, lubricating oil (Automatic Transmission Fluid) Lubricating oil, hereinafter also referred to as “ATF”). (“ATF” is a registered trademark of Idemitsu Kosan Co., Ltd.)

  However, in order to increase the response of the hydraulic clutch, the distance between the segment type friction material and the separator plate which is the counterpart material is set small, and in order to sufficiently secure the torque transmission capacity when the hydraulic clutch is engaged, The total area of the oil passage on the segment type friction material is limited. As a result, the ATF remaining between the segment type friction material and the separator plate is difficult to be discharged when the hydraulic clutch is not engaged, and there is a problem that drag torque due to ATF is generated by the relative rotation of both plates.

  Therefore, in Patent Document 1, an oil groove formed between adjacent segment pieces is defined, and the wet friction member is characterized in that the interval between the oil grooves is narrowed on the way from the inner peripheral side to the outer peripheral side. This invention is disclosed. As a result, the ATF flowing from the inner peripheral side to the outer peripheral side is blocked at the point where the oil groove interval changes, and a part of the ATF overflows the surface of the segment piece and flows through the surface of the segment piece. The cooling effect is improved, the heat resistance is improved, and the drag torque can be reduced.

  Further, in the invention described in Patent Document 2, since the two sides to which the opposite direction R is attached to the core of the segment piece are bonded so as to be the inner periphery and the outer periphery, the oil groove direction is formed on the inner periphery. And the width of the outer peripheral opening of the gap serving as the oil groove is larger than the width of the inner peripheral opening, thereby greatly improving the ATF discharge performance due to the idling of the segment type friction material, The drag torque by ATF is said to be greatly reduced.

  Furthermore, in the invention described in Patent Document 3, the segment type friction material is rotated in a non-fastened state when incorporated into the AT by cutting off the inner peripheral side angle of the segment piece at a predetermined angle in the segment type friction material. When the ATF supplied from the inner peripheral side comes into contact with the cut-off portion of the segment piece, the ATF is positively supplied to the friction surface of the friction material base, and the contact between the separator plate and the friction surface The drag torque caused by ATF is greatly reduced.

Further, in Patent Document 4, in a segment type friction material, in order to prevent the segment piece from peeling off due to an increase in the hydraulic pressure of the ATF that contacts the side surface of the segment piece (the surface constituting the oil groove), An invention is disclosed in which R is added to four corners, or four corners of a segment piece are chamfered. As a result, it is considered that the peel resistance is greatly improved, and when the shape of the four corners is appropriate, the drag torque due to ATF is reduced.
JP 2001-295859 A Japanese Patent Laying-Open No. 2005-06941 JP 2005-282648 A JP 2004-150449 A

  However, in the techniques described in Patent Document 1 to Patent Document 3, it is assumed that ATF is supplied from the inner peripheral side of the core of the segment type friction material, and in the actual machine, ATF is supplied from the hub hole. When there is no specification, or when the oil accumulation is generated on the outer periphery and the stirring torque becomes large, the effect of reducing the drag torque is still small, and it is difficult to realize significant fuel efficiency reduction in the vehicle There was a point.

  Moreover, in the technique of the said patent document 4, since it aims only at preventing that a segment piece peels, R and chamfering of four corners of the segment piece shown by embodiment are carried out. The effect of reducing drag torque cannot be obtained because it is too small, and an appropriate range of R and chamfer size at the four corners of the segment piece for reducing drag torque is not shown. Furthermore, there is a problem in that all four corners of the segment piece must be R-processed or chamfered, which is not always required to reduce drag torque.

  Therefore, the present invention reliably obtains a large drag torque reduction effect even when the specification is such that there is no supply of lubricating oil from the inner periphery side or when the oil pool is generated on the outer periphery and the stirring torque increases. It is an object of the present invention to provide a wet friction material that can be used.

  In the wet friction material according to the first aspect of the present invention, a friction material substrate cut into segment pieces along the flat ring shape is adjacent to a flat plate ring-shaped cored bar and is adhered to both or both sides of the entire circumference. A segment type friction material in which a plurality of oil grooves are formed in the radial direction by the gaps between the segment pieces, or an island-shaped portion in which a ring-shaped friction material base material is bonded to both sides or one side of a flat plate ring-shaped cored bar A ring-type friction material formed by pressing or cutting to form a plurality of oil grooves in the radial direction, and the outer peripheral side of the segment piece or the island-like portion sandwiched between the plurality of oil grooves One or both of the corners are R-processed or chamfered.

  A wet friction material according to a second aspect of the present invention is the wet friction material according to the first aspect, wherein all of the plurality of oil grooves are symmetrical in shape, and at least every two of the plurality of oil grooves have an outer peripheral opening. Is provided with an oil groove that is symmetrical and has a width that is at least four times the width of the narrowest portion of the plurality of oil grooves. Here, “at least every two of the plurality of oil grooves” means that at least every two oil grooves whose outer peripheral openings are expanded to a width of four times or more of the narrowest part of the oil groove are provided. This means that there may be a case where two or more oil grooves in which the outer peripheral opening is not expanded or two or more oil grooves in which the outer peripheral opening is expanded are provided continuously.

  The wet friction material according to a third aspect of the present invention is the configuration of the first aspect, wherein all of the plurality of oil grooves have a symmetrical shape, and all of the outer peripheral openings of the plurality of oil grooves are symmetrical. The width of the plurality of oil grooves is at least four times the width of the narrowest part of the plurality of oil grooves.

  The wet friction material according to a fourth aspect of the present invention is the wet friction material according to any one of the first to third aspects, wherein a circumferential width of the R processing or the chamfering processing is 3 mm or more, or the segment piece or the island. 3% of the width of the narrowest part of the plurality of oil grooves, which is 15% or more of the circumferential width of the annular part and 50% or less of the circumferential width of the segment piece or the island-like part. The radial width of the R processing or the chamfering processing is within a range of 20% to 100% of the radial width of the segment piece or the island-shaped portion.

  A wet friction material according to a fifth aspect of the present invention is the wet friction material according to any one of the first to fourth aspects, wherein the segment piece or the island-shaped portion of the island-shaped portion is sandwiched between the plurality of oil grooves. Is provided with a concave portion recessed with respect to the outer peripheral side.

  The wet friction material according to the invention of claim 1 is a segment in which a friction material base material cut into segment pieces along a flat plate ring shape is bonded to a whole surface or both sides of a flat plate ring-shaped cored bar. A segment type friction material in which a plurality of oil grooves are formed in the radial direction by the gap between pieces, or a ring-shaped friction material base material is bonded to both sides or one side of a flat ring-shaped core metal, leaving an island-shaped portion A ring-type friction material that is pressed or cut to form a plurality of oil grooves in the radial direction, and is one of the segment piece sandwiched between the plurality of oil grooves or one of the outer peripheral corners of the island-shaped part or Both are R-processed or chamfered.

  That is, the opening part on the outer peripheral side of the plurality of oil grooves extends in a curved line or linearly, and the expanded part in which the lubricating oil flowing from the outer peripheral side of the wet friction material is a part subjected to R processing or chamfering processing In this way, the surface of the segment piece or the island-shaped portion is easily overflowed, and a sufficient space for lubricating oil to flow around the outer periphery of the wet friction material is secured.

  With such a configuration, when the wet friction material idles in any direction in the non-fastened state, the lubricant supplied from the outer peripheral side of the wet friction material in the case of a specification in which no lubricant is supplied from the inner peripheral side In order to secure the space between the wet friction material and the separator plate by being dammed up at the expanded portion and overflowing the surface of the segment piece or the island-shaped portion, only the wet friction material is smoothly idled. Also, in the case of the specification in which the lubricating oil is supplied from the inner peripheral side, there is a sufficient space for the lubricating oil to flow on the outer periphery of the wet friction material, so that an oil pool is generated on the outer peripheral and the drag torque increases. It can be surely prevented.

  In this way, even when the specification is such that there is no supply of lubricating oil from the inner periphery side, or when the oil pool is generated on the outer periphery and the agitation torque increases, it is possible to reliably obtain a greater drag torque reduction effect. It can be a wet friction material.

  In the wet friction material according to the invention of claim 2, all of the plurality of oil grooves have a symmetrical shape, and at least every two of the plurality of oil grooves, the outer peripheral opening has a symmetrical shape and a plurality of oil grooves. An oil groove is provided that expands to a width that is at least four times the width of the narrowest part of the oil groove. Here, “at least every two of the plurality of oil grooves” means that at least every two oil grooves are provided with an outer circumferential opening having a width that is at least four times the width of the narrowest part of the oil groove. This means that there may be a case where two or more oil grooves in which the outer peripheral opening is not expanded or two or more oil grooves in which the outer peripheral opening is expanded are continuously provided.

  Thus, in addition to the effect of the invention according to the first aspect, in the case where the wet friction material idles in any direction, there is obtained an operational effect that an equivalent drag torque reduction effect can be obtained. In addition, since at least every two of the plurality of oil grooves, the outer peripheral opening extends to a width that is at least four times the width of the narrowest part of the oil groove, it is possible to reliably obtain a greater drag torque reduction effect. .

  In this way, even when the specification is such that there is no supply of lubricating oil from the inner periphery side, or when the oil pool is generated on the outer periphery and the agitation torque increases, it is possible to reliably obtain a greater drag torque reduction effect. It can be a wet friction material.

  In the wet friction material according to the invention of claim 3, all of the plurality of oil grooves are symmetric in shape, and all the outer peripheral openings of the plurality of oil grooves are symmetric in shape. It spreads over 4 times the width of the narrowest part.

  Thus, in addition to the effect of the invention according to the first aspect, in the case where the wet friction material idles in any direction, there is obtained an operational effect that an equivalent drag torque reduction effect can be obtained. In addition, since all the outer peripheral openings of the plurality of oil grooves extend to a width that is four times or more the width of the thinnest portion of the oil groove, a greater drag torque reduction effect can be obtained more reliably.

  In this way, even in the case of specifications where there is no supply of lubricating oil from the inner periphery side or when an oil pool is generated on the outer periphery and the agitation torque is increased, the effect of reducing the larger drag torque can be further ensured. It becomes the wet friction material which can be obtained.

  In the wet friction material according to the invention of claim 4, the circumferential width of R processing or chamfering is 3 mm or more, or 15% or more of the circumferential width of the segment piece or island-shaped portion, and the segment piece or island 50% or less of the width in the circumferential direction of the cylindrical portion and at least three times the width of the thinnest portion of the plurality of oil grooves, and the radial width of the R processing or chamfering processing is a segment piece or island It is in the range of 20% to 100% of the radial width of the shaped portion.

  As a result of diligent experiment research, the present inventors have found that the width in the circumferential direction of R machining or chamfering is 3 mm or more, or a segment piece or island in order to obtain a drag torque reduction effect more effectively in a wet friction material. 15% or more of the circumferential width of the groove-shaped portion, 50% or less of the circumferential width of the segment piece or island-shaped portion, and 3 times or more of the narrowest portion of the plurality of oil grooves Based on this finding, it was found that the radial width of the R processing or the chamfering processing needs to be within a range of 20% to 100% of the radial width of the segment piece or the island-shaped portion. The present invention has been completed.

  That is, when the circumferential width of the R processing or the chamfering processing is less than 3 mm or less than 15% of the circumferential width of the segment piece or the island-shaped portion, it is formed on the outer peripheral side of the oil groove of the wet friction material. Space where the width of the outer peripheral opening becomes small and there is a risk that the amount of lubricating oil supplied from the outer peripheral side will run short on the surface of the segment piece or island-shaped part, and the lubricating oil flows on the outer periphery of the wet friction material Is not secured sufficiently, an oil pool is generated on the outer periphery, and there is a possibility that the effect of reducing drag torque cannot be obtained sufficiently.

  On the other hand, when the circumferential width of the R processing or chamfering processing exceeds 50% of the circumferential width of the segment piece or the island-shaped portion, the width of the outer peripheral opening becomes too large, and on the contrary, lubrication from the outer peripheral side is performed. Oil supply may not go smoothly. In addition, when the segment piece or island-shaped portion is R-processed or chamfered into a symmetrical shape, the circumferential width of the processing is limited to 50% of the circumferential width of the segment piece or island-shaped portion. It becomes.

  Moreover, it is preferable that the width in the circumferential direction of R processing or chamfering processing is three times or more the width of the narrowest portion of the plurality of oil grooves. That is, the width of the outer peripheral opening is at least 4 times the width of the narrowest part of the oil groove (when R processing or chamfering is applied only to one side of the oil groove) or 7 times or more (R processing or chamfering is oil It is preferable that it is applied to both sides of the groove).

  Furthermore, when the radial width of the R processing or the chamfering processing is less than 20% of the circumferential width of the segment piece or the island-shaped portion, the outer peripheral opening formed on the outer peripheral side of the oil groove of the wet friction material As the depth becomes shallower, the amount of lubricating oil supplied from the outer peripheral side may run short on the surface of the segment piece or island part, and there is sufficient space for the lubricating oil to flow around the wet friction material. Since this is not ensured, there is a risk that an oil reservoir will be generated on the outer periphery, and the effect of reducing drag torque will not be sufficiently obtained. The limit in the circumferential direction of R processing or chamfering is 100% of the radial width of the segment piece or island-shaped portion.

  Here, the circumferential width of R processing or chamfering is in the range of 25% to 40% of the circumferential width of the segment piece or island-shaped portion, and the radial width of R processing or chamfering is A range of 25% to 50% of the radial width of the segment piece or the island-like portion is more preferable because the effect of reducing the drag torque can be more sufficiently obtained.

  In this way, even when the specification is such that no lubricating oil is supplied from the inner circumference side, or when the oil pool is generated on the outer circumference and the agitation torque is increased, a greater drag torque reduction effect can be obtained more reliably. It becomes a wet friction material capable of

  In the wet friction material according to the fifth aspect of the present invention, a concave portion that is recessed with respect to the outer peripheral side is provided at the outer peripheral side central portion of the segment piece or island-shaped portion sandwiched between the plurality of oil grooves.

  As a result, the lubricating oil supplied from the outer peripheral side overflows not only from the R-processed or chamfered part, but also from the concave part to the surface of the segment piece or island-like part, so that a greater drag torque reduction effect can be obtained. In addition, since the space in which the lubricating oil on the outer periphery of the wet friction material flows becomes wider, it is possible to more reliably prevent the occurrence of an oil reservoir on the outer periphery and an increase in drag torque.

  In this way, even when the specification is such that no lubricating oil is supplied from the inner circumference side, or when the oil pool is generated on the outer circumference and the agitation torque is increased, a greater drag torque reduction effect can be obtained more reliably. It becomes a wet friction material capable of

  Embodiments of the present invention will be described below with reference to the drawings. In the second and subsequent embodiments, the same symbols and the same reference numerals as those in the first embodiment mean the same or corresponding functional parts as those in the first embodiment, and the same symbols and the same in the embodiments. The reference numeral is a functional part common to those embodiments, and therefore detailed description thereof is omitted here.

Embodiment 1
First, a wet friction material according to Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1A is a partial plan view showing a part of a wet friction material (Example 1) according to Embodiment 1 of the present invention, and FIG. 1B shows a first modification of Embodiment 1 of the present invention. The partial top view which showed a part of wet wet friction material (Example 2) which concerns, (c) shows a part of wet friction material (Example 3) which concerns on the 2nd modification of Embodiment 1 of this invention. FIG. FIG. 2A is a partial cross-sectional view showing a longitudinal section of the wet friction material (Example 1) according to Embodiment 1 of the present invention, and FIG. 2B is a third modification of Embodiment 1 of the present invention. It is the fragmentary sectional view which showed the longitudinal cross-section of the wet friction material which concerns. 3 (a) and 3 (b) are partial plan views showing a part of a wet friction material according to another modification of the first embodiment of the present invention. 4 (a), (b), (c), (d), (e), and (f) are the shapes of the segment pieces used in the wet friction material according to another modification of the first embodiment of the present invention. FIG.

  FIG. 5A is a partial plan view showing a part of a wet friction material according to a fourth modification of the first embodiment of the present invention, and FIG. 5B shows a fifth modification of the first embodiment of the present invention. The partial top view which showed a part of the wet friction material which concerns, (c) is the partial top view which showed a part of wet friction material which concerns on the 6th modification of Embodiment 1 of this invention, (d) is this The partial top view which showed a part of wet friction material which concerns on the 7th modification of Embodiment 1 of invention, (e) is a part of wet friction material which concerns on the 8th modification of Embodiment 1 of this invention. It is the fragmentary top view which showed.

  6A is a partial plan view showing a part of the wet friction material according to the first example of the prior art (Comparative Example 1), and FIG. 6B is a wet friction material according to the second example of the prior art (Comparative Example). 2) is a partial plan view showing a part of (2), and (c) is a partial plan view showing a part of a wet friction material (Comparative Example 3) according to a third example of the prior art. FIG. 7 compares the relationship between the relative rotational speed and drag torque of the wet friction material according to the first embodiment of the present invention (Examples 1, 2, and 3) with that of the conventional wet friction material (Comparative Examples 1, 2, and 3). It is a figure shown. FIG. 8 is a diagram showing the relationship between parameters in the wet friction material (Example 1) according to Embodiment 1 of the present invention.

  FIG. 9 is a diagram showing the relationship between the cutting height (width in the radial direction) of the outer peripheral corner portion of the oil groove and the drag torque reduction rate in the wet friction material (Example 1) according to Embodiment 1 of the present invention. FIG. 10 is a diagram showing the relationship between the cut length (circumferential width) of the outer peripheral corner portion of the oil groove and the drag torque reduction rate in the wet friction material (Example 1) according to Embodiment 1 of the present invention. . FIG. 11A is an explanatory view showing the generation of drag torque in a conventional wet friction material (Comparative Example 1), and FIG. 11B is the drag torque in the wet friction material (Example 1) according to Embodiment 1 of the present invention. It is explanatory drawing which shows the reduction effect.

  As shown in FIG. 1 (a), a segment type friction material 1 as a wet friction material (Example 1) according to the first embodiment includes a flat ring-shaped steel plate core 2 and a wet friction material. A plurality of segment pieces 3 obtained by cutting out a normal friction material base material for use with adhesive (thermosetting resin) are arranged and pasted at intervals of oil grooves 4, and the same is applied to the back surface of the core metal 2 Affixed with an adhesive. Here, the left and right outer peripheral corners of the segment piece 3 have a notch 3a whose height (the width in the radial direction of the segment type friction material 1) is α mm and whose length (the width in the circumferential direction of the segment type friction material 1) is β mm. Is provided.

  That is, in the segment type friction material 1 as the wet friction material (Example 1) according to the first embodiment, both the outer peripheral side corners of the segment piece 3 sandwiched between the plurality of oil grooves 4 are chamfered. The plurality of oil grooves 4 are all symmetric in shape, and all the peripheral openings of the plurality of oil grooves 4 are symmetric in shape, and the width of the narrowest part of the plurality of oil grooves 4 is 4. It spreads more than double. Therefore, the segment type friction material 1 according to the first embodiment corresponds to the wet friction material according to the first and third aspects of the invention.

  Further, as shown in FIG. 1 (b), a segment type friction material 1A as a wet friction material (Example 2) according to the first modification of the first embodiment is a flat plate ring-shaped steel plate core. A plurality of segment pieces 3A and 3B obtained by cutting out a normal friction material base material for wet friction material on gold 2 are alternately arranged using an adhesive (thermosetting resin) with an interval between oil grooves 4A and 4B. Are attached to the back of the metal core 2 and are similarly attached to the back surface of the metal core 2 with an adhesive. Here, the left outer peripheral corner of the segment piece 3A and the right outer peripheral corner of the segment piece 3B each have a height (the width in the radial direction of the segment type friction material 1A) and a length (segment type friction material). Cuts 3Aa and 3Ba having a width of 1A in the circumferential direction) are provided.

  That is, in the segment type friction material 1A as the wet friction material (Example 2) according to the first modification of the first embodiment, the outer periphery of the segment pieces 3A and 3B sandwiched between the plurality of oil grooves 4A and 4B. One of the side corners is chamfered, and all of the plurality of oil grooves 4A, 4B have a bilaterally symmetrical shape, and the outer peripheral opening is bilaterally symmetrical every other one of the plurality of oil grooves 4A, 4B. An oil groove 4A that is widened to a width that is at least four times the width of the thinnest part of the plurality of oil grooves 4A, 4B is provided. Therefore, the segment type friction material 1A according to the first modification of the first embodiment corresponds to the wet friction material according to the inventions of claims 1 and 2.

  Further, as shown in FIG. 1 (c), the segment type friction material 1C as the wet friction material (Example 3) according to the second modification of the first embodiment is a flat plate ring-shaped steel plate core. A plurality of segment pieces 3C obtained by cutting out a normal friction material base material for wet friction materials are attached to gold 2 with adhesive (thermosetting resin) arranged at intervals of oil grooves 4C. Similarly, it is affixed to the back surface of the gold 2 with an adhesive. Here, the left and right outer peripheral corners of the segment piece 3C have a height (width in the radial direction of the segment type friction material 1C) of (α1) mm and a length (width in the circumferential direction of the segment type friction material 1C) of 50. % Cut 3Ca is provided. That is, the outer peripheral side of the segment piece 3C is completely cut off from the left and right. Then, α1 = (3/4) α.

  That is, in the segment type friction material 1C as the wet friction material (Example 3) according to the second modified example of the first embodiment, the corners on the outer peripheral side of the segment piece 3C sandwiched between the plurality of oil grooves 4C. Both are chamfered, and all of the plurality of oil grooves 4C have a bilaterally symmetric shape, and all the outer peripheral openings of the plurality of oil grooves 4C have a bilaterally symmetric shape, and are the narrowest of the plurality of oil grooves 4C. It spreads over 4 times the width of the part. Therefore, the segment type friction material 1C according to the second modification of the first embodiment corresponds to the wet friction material according to the inventions of claims 1 and 3.

  Here, FIG. 2 shows the structure of the vertical section of the wet friction material (Example 1) according to the first embodiment and the structure of the vertical section of the wet friction material according to the third modification of the first embodiment. The description will be given with reference. As shown in FIG. 2A, in the segment type friction material 1 as the wet friction material (Example 1) according to the first embodiment, the segment piece 3 is formed on the front surface side and the back surface side of the core metal 2. The bonding positions in the circumferential direction are substantially the same, and therefore the positions of the oil grooves 4 in the circumferential direction are also substantially the same on the front and back sides.

  On the other hand, as shown in FIG. 2B, in the segment type friction material 1F as the wet friction material according to the third modification of the first embodiment, the front side and the back side of the cored bar 2 Thus, the bonding position of the segment piece 3 in the circumferential direction is shifted, and therefore the position of the oil groove 4 in the circumferential direction is also shifted on the front and back sides.

  That is, the bonding position of the segment piece 3 and the position of the oil groove 4 in the circumferential direction may be random on the front and back of the core metal 2, and the core as in the segment type friction material 1 shown in FIG. The front and back of the gold 2 may coincide with each other, or the front and back of the core metal 2 may be displaced as in the segment type friction material 1F shown in FIG. The same applies to other segment type friction materials described in the first embodiment.

  Next, a wet friction material according to another modification of the first embodiment will be described with reference to FIG.

  As shown in FIG. 3 (a), a segment type friction material 1D as a wet friction material according to another modification of the first embodiment includes a flat metal ring 2 and a wet friction material. A plurality of segment pieces 3, 3A, 3B cut out of a normal friction material base material for use with adhesive (thermosetting resin) are arranged and pasted at intervals of oil grooves, and the back surface of the core metal 2 In the same manner, it is affixed with an adhesive.

  Here, in FIG. 3 (a), (b), the oil groove provided between the segment piece 3 and the segment piece 3A, and the oil groove provided between the segment piece 3 and the segment piece 3B ( In any case, the outer peripheral opening has a left-right symmetric shape and spreads to a width that is at least four times the width of the narrowest portion of the plurality of oil grooves).

  As shown in FIG. 3A, in the segment type friction material 1D, after the two segment pieces 3 are pasted, two segment pieces 3A and two segment pieces 3B are pasted alternately. It is repeated over the circumference. As a result, three oil grooves 4D, 4 and 4D, which have a symmetrical outer peripheral opening and have a width that is four times the width of the narrowest part of the plurality of oil grooves, are continuously arranged, and the outer peripheral opening is One oil groove 4B that is not expanded is arranged with one oil groove 4B that is not expanded, and one oil groove 4B that is not expanded with the outer periphery opening is further interposed, and the outer periphery opening is expanded. Three oil grooves 4D, 4 and 4D are continuously arranged.

  Further, as shown in FIG. 3B, a segment type friction material 1E as a wet friction material according to another modification of the first embodiment is wetted on a core metal 2 made of a flat plate ring-shaped steel plate. A plurality of segment pieces 3, 3A, 3B obtained by cutting out a normal friction material base material for friction material are pasted and arranged with an oil groove interval using an adhesive (thermosetting resin), and a cored bar 2 Similarly, it is affixed to the back surface of the film with an adhesive.

  As shown in FIG. 3 (b), in the segment type friction material 1E, the segment piece 3, the segment piece 3A, and the segment piece 3B are sequentially attached in the clockwise direction (clockwise), and this extends over the entire circumference. Has been repeated. As a result, two oil grooves 4D that have a circumferentially symmetric shape of the outer peripheral opening and that extend to a width of four times or more the width of the narrowest part of the plurality of oil grooves are continuously arranged, and the outer peripheral opening is not expanded. Two oil grooves 4 </ b> D having one groove 4 </ b> B sandwiched between them and the outer peripheral opening portion being expanded are arranged in a row.

  That is, in the invention according to claim 2, “at least every second of the plurality of oil grooves” means that the outer peripheral opening has expanded to a width of four times or more the width of the narrowest part of the oil groove at least every two oil grooves. This means that an oil groove is provided, and there are cases where two or more oil grooves in which the outer peripheral opening is not expanded or two or more oil grooves in which the outer peripheral opening is expanded are provided continuously.

  Therefore, the segment type friction materials 1D and 1E as the wet friction materials according to other modifications of the first embodiment correspond to the wet friction materials according to the inventions of claims 1 and 2.

  Furthermore, the shape of the segment piece used for the wet friction material which concerns on the other modification of this Embodiment 1 is demonstrated with reference to FIG.

  The segment piece 3D shown in FIG. 4 (a) is R-processed at both outer corners, and the segment piece 3E shown in FIG. 4 (b) has both outer corners shown in FIG. The segment piece 3F shown in FIG. 4 (c) is rounded to the middle portion of the outer periphery.

  Therefore, the segment type friction material as the wet friction material according to another modification of the first embodiment using the segment pieces 3D, 3E, and 3F is the wet friction according to the inventions of claims 1 and 3. Corresponds to the material.

  In addition, the segment piece 3G shown in FIG. 4 (d) is provided with a recess 3g having a width gmm that is recessed with respect to the outer peripheral side at the outer peripheral side central portion, while both of the outer peripheral corners are chamfered. The segment piece 3H shown in FIG. 4 (e) is R-processed at both corners on the outer peripheral side and is provided with a concave portion 3h having a width hmm that is recessed with respect to the outer peripheral side at the central portion of the outer peripheral side. The segment piece 3I shown in (f) is chamfered at both corners on the outer peripheral side, and is provided with a recess 3i having a width imm that is recessed with respect to the outer peripheral side at the central portion on the outer peripheral side.

  Therefore, the segment type friction material as the wet friction material according to the other modification of the first embodiment using the segment pieces 3G, 3H, and 3I, respectively, is the invention of claim 1, claim 3 and claim 5. It corresponds to the wet friction material concerning.

Accordingly, in the segment type friction material using these segment pieces 3G, 3H, and 3I, the lubricating oil supplied from the outer peripheral side is not only from the R processing or chamfering portion but also from the recesses 3g, 3h, and 3i. Since it overflows to the surface of the segment pieces 3G, 3H, 3I, it is possible to obtain a greater drag torque reduction effect, and a wider space for the lubricating oil on the outer periphery of the wet friction material to be increased. It is possible to more reliably prevent a situation where an oil reservoir is generated and drag torque increases.

  Furthermore, a wet friction material according to another modification of the first embodiment will be described with reference to FIG.

  As shown in FIG. 5 (a), a segment type friction material 1G as a wet friction material according to the fourth modification of the first embodiment includes a flat ring-shaped steel cored bar 2 and a wet friction material. A plurality of segment pieces 3J obtained by cutting out a normal friction material base material for use with an adhesive (thermosetting resin) with the oil grooves 4E being spaced apart and pasted, and the same on the back surface of the core metal 2 Affixed with an adhesive. The segment piece 3J is larger in height (radial width) and length (circumferential width) than the above-described segment piece 3 and the like, so the number of oil grooves 4E is 30 on the entire circumference. It is less than the segment type friction material 1 described above.

  Here, the left and right outer peripheral corners of the segment piece 3J are cut (chamfered) 3Ja, and the central part of the outer periphery of the segment piece 3J has a recess 3j having a width jmm that is recessed with respect to the outer peripheral side. Is provided. Accordingly, the segment type friction material 1G as the wet friction material according to the fourth modification of the first embodiment using the segment piece 3J is the wet friction according to the inventions of claims 1, 3 and 5. Corresponds to the material.

  Thereby, the segment type friction material 1G has the effect of reducing the drag torque more reliably because the lubricant supplied from the outer peripheral side overflows not only from the chamfered portion 3Ja but also from the recess 3j to the surface of the segment piece 3J. In addition, since the space through which the lubricating oil on the outer periphery of the segment type friction material 1G flows becomes wider, it is possible to more reliably prevent a situation where an oil reservoir is generated on the outer periphery and drag torque increases. .

  Further, as shown in FIG. 5B, the segment type friction material 1H as the wet friction material according to the fifth modification of the first embodiment is wetted on the core metal 2 made of a flat plate ring-shaped steel plate. A plurality of segment pieces 3K, 3L cut out of a normal friction material base material for a friction material are pasted alternately using an adhesive (thermosetting resin) with an interval between oil grooves 4F, 4G. The back surface of the cored bar 2 is similarly attached with an adhesive. The segment pieces 3K and 3L are larger in height (radial width) than the above-described segment pieces 3 and the like, but have the same length (circumferential width). Therefore, the oil grooves 4F, The number of 4G is 40 on the entire circumference, which is the same as the segment type friction material 1 described above.

  Here, the right outer peripheral corner of the segment piece 3K is chamfered 3Ka over almost the entire outer surface of the segment piece 3K, and the left outer peripheral corner of the segment piece 3L has a segment piece 3L. A chamfering process 3La is applied over substantially the entire outer peripheral side of the plate. Therefore, the segment type friction material 1H as the wet friction material according to the fifth modification of the first embodiment using the segment pieces 3K and 3L is the wet friction material according to the inventions of claims 1 and 2. Applicable.

  Further, as shown in FIG. 5 (c), a segment type friction material 1J as a wet friction material according to the sixth modification of the first embodiment is wetted on a core metal 2 made of a steel plate having a flat ring shape. A plurality of segment pieces 3K, 3L, 3M, and 3N cut out from a normal friction material base material for a friction material are arranged in this order in the clockwise direction (clockwise), and an adhesive (thermosetting resin) is used. The oil grooves 4F, 4H, 4J, and 4K are pasted at intervals, and the back surface of the cored bar 2 is similarly pasted with an adhesive.

  Here, a cut (chamfering) 3Ma is applied to the right outer peripheral corner of the segment piece 3M, and a cut (chamfering) 3Na is applied to the left outer peripheral corner of the segment piece 3N. Therefore, the segment type friction material 1J as the wet friction material according to the sixth modification of the first embodiment using the segment pieces 3K, 3L, 3M, 3N is related to the inventions of claims 1 and 2. Corresponds to wet friction material.

  Further, as shown in FIG. 5 (d), a segment type friction material 1K as a wet friction material according to the seventh modification of the first embodiment is wetted on a metal core 2 made of a steel plate having a flat ring shape. A plurality of segment pieces 3K obtained by cutting out a normal friction material base material for a friction material are arranged and pasted at intervals of oil grooves 4L using an adhesive (thermosetting resin). Is also affixed with an adhesive. Therefore, the segment type friction material 1K as the wet friction material according to the seventh modified example of the first embodiment using the segment piece 3K corresponds to the wet friction material according to the invention of claim 1.

  Further, as shown in FIG. 5 (e), a segment type friction material 1L as a wet friction material according to the eighth modification of the first embodiment is wetted on a metal core 2 made of a flat plate ring-shaped steel plate. A plurality of segment pieces 3L, 3M cut out of a normal friction material base material for friction material are pasted alternately using an adhesive (thermosetting resin) at intervals of oil grooves 4H, 4M. The back surface of the cored bar 2 is similarly attached with an adhesive. Therefore, the segment type friction material 1L as the wet friction material according to the eighth modification of the first embodiment using the segment pieces 3L and 3M corresponds to the wet friction material according to the invention of claim 1.

  As a result, these segment type friction materials 1H, 1J, 1K, and 1L are surely more reliable because the lubricating oil supplied from the outer peripheral side overflows from the chamfered portion to the surface of the segment pieces 3K, 3L, 3M, and 3N. A large drag torque reduction effect can be obtained, and the space where the lubricating oil flows on the outer periphery of the wet friction material becomes wider, so it is possible to more reliably prevent the drag torque from increasing due to an oil pool on the outer periphery. can do.

  Next, a segment type friction material as a wet friction material according to the prior art will be described with reference to FIG.

  As shown in FIG. 6 (a), a segment type friction material 11 as a wet friction material (Comparative Example 1) according to a first example of the prior art is applied to a metal core 2 made of a flat plate ring-shaped steel plate. A plurality of segment pieces 13 obtained by cutting out a normal friction material base material for a material are attached with an oil groove 14 spaced apart using an adhesive (thermosetting resin). Similarly, it is affixed with an adhesive. The segment type friction material 11 according to the first example of the related art having such a configuration corresponds to an example of the segment type friction material according to the invention of Patent Document 4.

  Further, as shown in FIG. 6 (b), the segment type friction material 11A as the wet friction material (Comparative Example 2) according to the second example of the prior art is formed on a metal core 2 made of a steel plate having a flat ring shape. A plurality of segment pieces 13A and 13B obtained by cutting out a normal friction material base material for wet friction materials are pasted alternately using an adhesive (thermosetting resin) at intervals of oil grooves 14A and 14B. The back surface of the cored bar 2 is similarly attached with an adhesive.

  Here, each of the left inner peripheral corner of the segment piece 13A and the right inner peripheral corner of the segment piece 13B has a height (segment type friction material 11A radial width) of α mm and a length (segment type). Cuts 13 </ b> Aa and 13 </ b> Ba having a width of β mm of the friction material 11 </ b> A in the circumferential direction are provided. 11 A of segment type friction materials which concern on the 2nd example of the prior art of this structure correspond to an example of the segment type friction material which concerns on the invention of the said patent document 3. FIG.

  Further, as shown in FIG. 6 (c), the segment type friction material 11C as the wet friction material (Comparative Example 3) according to the third example of the prior art is formed on the metal core 2 made of a steel plate having a flat ring shape. A plurality of segment pieces 13C obtained by cutting out a normal friction material base material for wet friction materials are pasted with an adhesive (thermosetting resin) at intervals of oil grooves 14C, and the back surface of the core metal 2 is attached. In the same manner, it is affixed with an adhesive. The segment type friction material 11C according to the third example of the related art having such a configuration corresponds to an example of the segment type friction material according to the invention of Patent Document 2.

  Of the segment type friction materials according to the first embodiment described above, the segment type friction material 1 (Example 1), the segment type friction material 1A (Example 2) according to the first modification, and the second modification example. Segment type friction material 1C (Example 3), segment type friction material 11 according to the first example of the prior art (Comparative Example 1), segment type friction material 11A according to the second example of the prior art (Comparative Example 2), And about the segment type friction material 11C (comparative example 3) which concerns on the 2nd example of a prior art, the relationship between relative rotation speed and drag torque was verified by the test.

  The size of each segment piece is as follows: the width of the segment piece = 13 mm, the vertical width of the segment piece 3 = 5 mm, the number of segment pieces is 40 on one side (80 on both sides), and the width of the narrowest part of the oil groove is 1 mm. α = 2 mm and β = 2 mm. That is, in the segment piece 3, the circumferential width (2 mm) of the chamfering process is 15.4% of the circumferential width (13 mm) of the segment piece 3, and the radial width (2 mm) of the chamfering process. Is 40% of the radial width (5 mm) of the segment piece. The same applies to the segment pieces 3A and 3B.

  Further, in the segment piece 3C, the circumferential width (6.5 mm) of the chamfering process is 50% of the circumferential width (13 mm) of the segment piece 3, and the radial width (α1 = chamfering process). (3/4) α = (3/4) × 2 mm = 1.5 mm) is 30% of the radial width (5 mm) of the segment piece. Therefore, the segment type friction materials 1, 1A, 1C as the wet friction material according to the first embodiment also correspond to the wet friction material according to the invention of claim 4.

  As test conditions, the relative rotational speed = 500 to 7000 rpm, ATF oil temperature = 40 ° C., ATF oil amount = 500 mL / min (without shaft center lubrication), disk size shown in FIGS. 1 and 3, outer periphery φ1 = 185 mm, The test was performed at an inner circumference φ2 = 175 mm, and the number of disks was 7 (therefore, 8 steel plate disks were used as mating members) and the pack clearance was 0.25 mm / sheet. The result of the test is shown in FIG.

  As shown in FIG. 7, when the relative rotational speed is 500 rpm, there is already a large difference between Examples 1, 2, and 3 and Comparative Examples 1 and 2, and this Embodiment 1 (Implementation) The segment type friction materials 1, 1A, 1C according to Examples 1, 2, 3) have a smaller drag torque than the segment type friction materials 11, 11A, 11C according to Comparative Examples 1, 2, 3). Yes.

  After that, as the relative rotational speed increases, since the condition of no shaft center lubrication is present, the drag torque of any segment type friction material decreases, but at the time when the relative rotational speed is 1000 rpm, 1500 rpm, 2000 rpm, the embodiment The difference between 1, 2, 3 and Comparative Examples 1, 2, 3 is maintained. And, when the relative rotational speed is 2500 rpm, there is almost no difference between Examples 1, 2, 3 and Comparative Examples 1, 3, but only Comparative Example 2 still has a large drag torque until it reaches 7000 rpm. The drag torque remains larger than those in Examples 1, 2, and 3.

  Thus, the segment type friction materials 1, 1A, 1C according to the first embodiment (Examples 1, 2, 3) are the segment type friction materials 11, 11A, 11C according to the conventional technology (Comparative Examples 1, 2). , 3), it was demonstrated that the drag torque reduction effect is greater.

  As shown in FIG. 7, the segment type friction material 1 </ b> C according to the third example is related to the first and second examples over the entire range of the relative rotational speed at which the test was performed = 500 to 7000 rpm. The result shows that the drag torque is smaller than that of the segment type friction materials 1 and 1A. Therefore, among the segment type friction materials 1, 1A, 1C according to the first embodiment, the segment type friction material 1C, that is, the segment type friction that is chamfered symmetrically to the center on the outer peripheral side of the segment piece. It was found that the material was more effective in reducing drag torque.

  Therefore, in order to obtain a larger drag torque suppression effect, the segment type friction material 1 of the first embodiment shown in FIG. 8 and the six parameters relating to the segment piece 3 used for the segment type friction material 1, that is, the notch 3a. (The width in the radial direction) α, the length of the cut 3a (the width in the circumferential direction) β, the width γ of the thinnest portion of the oil groove 4, the lateral width δ of the segment piece 3, and the vertical width ε of the segment piece 3 An experiment was conducted to obtain optimum values for the width σ of the outer peripheral opening of the oil groove 4.

  Among them, the bar graphs of FIGS. 9 and 10 show the experimental results for the height α and the length β of the cut 3a. First, in order to obtain the optimum value of the height α of the notch 3a, a sample with the notch length β = 2.0 mm fixed and the notch height α varied in four ways was prepared and incorporated in the AT actual machine, The drag torque reduction rate was measured.

  The drag torque reduction rate is expressed as an average value of two measured values when the rotation speed of the segment type friction material 1 is 1000 rpm and 1500 rpm. When the cutting height α = 2 mm and the cutting length β = 2.0 mm, that is, when the drag torque reduction rate is increased as compared with the first embodiment with reference to the first embodiment shown in FIG. The case where the drag torque reduction rate is reduced is shown as minus.

  As for other parameters shown in FIG. 8, the width γ = 1 mm of the thinnest portion of the oil groove 4, the horizontal width δ = 13 mm of the segment piece 3, and the vertical width ε = 5 mm of the segment piece 3, , ATF oil temperature = 40 ° C., ATF oil amount = 500 mL / min (no shaft center lubrication), disk size tested at outer circumference φ1 = 185 mm, inner circumference φ2 = 175 mm, and the number of disks = 7 Eight steel plate disks) and pack clearance = 0.25 mm / sheet.

  As a result, as shown in FIG. 9, when the cutting height α is 1.0 mm and 1.5 mm, which is smaller than that of Example 1, the drag torque reduction rate is reduced to a negative value. When the cutting height α was 2.5 mm, which was larger than that of Example 1, the value was positive. As a result, it is considered that the drag torque reduction effect improves as the cutting height α increases.

  On the other hand, in order to obtain the optimum value of the length β of the cut 3a, a sample with the cut height α fixed at 2.0 mm and the cut length β changed in four ways was built into the AT actual machine, The drag torque reduction rate was measured under the same test conditions. As a result, as shown in FIG. 10, when the cutting length β is 1.0 mm and 1.5 mm, which is smaller than that of Example 1, the drag torque reduction rate is decreased to a negative value. When the cut length β was 2.5 mm, which was larger than that of Example 1, the value was positive. As a result, it is considered that the drag torque reduction effect improves as the cut length β increases.

  Furthermore, as a result of repeated experiments on the relationship between the other parameters shown in FIG. 8, the cutting height α = in the range of 25% to 50% of the vertical width ε of the segment piece 3, and the cutting length β ≦ 0. 5 × (lateral width δ of segment piece 3), width σ of outer peripheral opening of oil groove 4 ≧ 4 × (width γ of the thinnest portion of oil groove 4) The higher drag torque reduction effect It became clear that can be obtained.

  As described above, in the case where the specification is such that there is no supply of lubricating oil (ATF) from the inner peripheral side of the wet friction material (without axial center lubrication), that is, the lubricating oil is supplied only from the outer peripheral side of the wet friction material. In the case of a segment type friction material, ATF flows from the processed part to the surface of the segment piece by R-processing or chamfering one or both of the outer peripheral side corners of the segment piece, A high drag torque reduction effect is obtained due to the peeling-off effect.

  On the other hand, the case where lubricating oil (ATF) is supplied from the inner peripheral side of a wet friction material is demonstrated with reference to FIG. As shown in FIG. 11A, in the segment type friction material 11 as the wet friction material (Comparative Example 1) according to the first example of the prior art, the stirring torque due to ATF accumulated on the outer peripheral portion is large. The drag torque will increase.

  On the other hand, as shown in FIG. 11 (b), in the segment type friction material 1 as the wet friction material (Example 1) according to the first embodiment, a cut 3 a is formed on the outer periphery of the segment piece 3. By providing, the stirring torque due to ATF can be suppressed, and the drag torque is reduced by the peeling effect that ATF flows from the notch 3a to the surface of the segment piece 3 and enters the mating material.

  As described above, when the lubricating oil is supplied only from the outer peripheral side, cutting the inner periphery of the segment piece has little effect of reducing the drag torque, but the lubricating oil (ATF) is supplied from the inner peripheral side. ), A higher drag torque reduction effect can be obtained by providing a cut on the outer periphery of the segment piece and also making a cut on the inner periphery of the segment piece.

  Thus, in the segment type friction materials 1, 1A and 1C as the wet friction materials according to the first embodiment, the specification (without the shaft center lubrication) in which the lubricating oil is not supplied from the inner peripheral side or Even when an oil pool is generated on the outer periphery and the stirring torque increases, a larger drag torque reduction effect can be obtained more reliably.

Embodiment 2
Next, a wet friction material according to Embodiment 2 of the present invention will be described with reference to FIGS. 12 (a) is a partial plan view showing a part of the wet friction material according to Embodiment 2 of the present invention, and FIG. 12 (b) shows a longitudinal section of the wet friction material according to Embodiment 2 of the present invention. Partial sectional view, (c) is a partial plan view showing a part of a wet friction material according to a first modification of the second embodiment of the present invention, and (d) is a second modification of the second embodiment of the present invention. It is the fragmentary top view which showed a part of wet friction material which concerns on an example.

  FIG. 13 (a) is a partial sectional view showing a longitudinal section of a wet friction material according to a third modification of the second embodiment of the present invention, and FIG. 13 (b) is a fourth modification of the second embodiment of the present invention. (C) is a partial plan view showing a part of the wet friction material according to the fifth modification of the second embodiment of the present invention. 14 (a) is a partial plan view showing a part of a wet friction material according to a sixth modification of the second embodiment of the present invention, and FIG. 14 (b) is a seventh modification of the second embodiment of the present invention. (C) is a partial plan view showing a part of the wet friction material according to the eighth modification of the second embodiment of the present invention.

  As shown in FIGS. 12A and 12B, the wet friction material 6 according to the second embodiment is different from the first embodiment (segment type friction material) in that the core metal plate made of a steel plate having a flat ring shape. A ring-shaped friction material base material 7 obtained by cutting out a normal friction material base material for wet friction material is bonded to both surfaces of 2 using an adhesive (thermosetting resin), and both surfaces are pressed. By doing so, it is a ring type friction material formed by forming a plurality (40 on one side) of oil grooves 9 with the island-like portion 8 interposed therebetween.

  Here, the oil groove 9 is an oil groove in which the outer peripheral opening is expanded in a symmetrical shape, and both the outer peripheral side corners of the island-like portion 8 sandwiched between the plurality of oil grooves 9 to 9 are chamfered (8a The plurality of oil grooves 9 are all symmetric in shape, and the outer peripheral openings of the plurality of oil grooves 9 are symmetric, and the width of the narrowest part of the plurality of oil grooves 9 is It has spread to more than 4 times. Therefore, the ring type friction material 6 according to the second embodiment corresponds to the wet friction material according to the inventions of claims 1 and 3.

  Further, the radial height X (mm) and the circumferential direction of the chamfered portion 8a of the island-shaped portion 8 of the friction material base in the outer peripheral opening of the oil groove 9 in which the outer peripheral portion extends in a symmetrical shape. About length Y (mm), it was set as the same dimension as (alpha) and (beta) in the segment type friction material 1 which concerns on the said Embodiment 1. FIG. That is, X = 2 mm and Y = 2 mm.

  Further, the horizontal width of the island-shaped portion 8 and the vertical width of the island-shaped portion 8 are the same dimensions as the segment piece 3 in the segment type friction material 1 according to the first embodiment, that is, the island-shaped portion. The horizontal width of 8 was 13 mm, and the vertical width of the island-shaped portion 8 was 5 mm. Therefore, the ring type friction material 6 as the wet friction material according to the second embodiment also corresponds to the wet friction material according to the invention of claim 4.

  Further, as shown in FIG. 12 (c), the wet friction material 6A according to the first modification of the second embodiment is used for the wet friction material over the entire surface of the cored bar 2 made of a flat ring metal plate. The ring-shaped friction material base material 7 cut out of the normal friction material base material is bonded using an adhesive (thermosetting resin), and both sides are pressed to form island portions 8A and 8B. Is a ring type friction material formed with a plurality of (40 on one side) oil grooves 9A, 9B. Here, the left outer peripheral corner portion of the island-shaped portion 8A and the right outer peripheral corner portion of the island-shaped portion 8B have a height (radial width) of Xmm and a length (circumferential width) of Ymm, respectively. Chamfering 8Aa and 8Ba are applied.

  That is, in the ring type friction material 6A as the wet friction material according to the first modification of the second embodiment, the corners on the outer peripheral side of the island portions 8A and 8B sandwiched between the plurality of oil grooves 9A and 9B. One side is chamfered, and the plurality of oil grooves 9A, 9B are all symmetrical in shape, and the outer peripheral openings are symmetrically formed in every other oil groove 9A, 9B. An oil groove 9A is provided that extends to a width that is four times or more the width of the narrowest part of the oil grooves 9A, 9B. Therefore, the ring type friction material 6A according to the first modification of the second embodiment corresponds to the wet friction material according to the inventions of claims 1 and 2.

  Further, the width in the horizontal direction of the island-shaped portions 8A and 8B and the width in the vertical direction of the island-shaped portions 8A and 8B are the same dimensions as the segment piece 3 in the segment type friction material 1 according to the first embodiment, that is, The lateral width of the island portions 8A and 8B = 13 mm, and the longitudinal width of the island portions 8A and 8B = 5 mm. Therefore, the ring type friction material 6A as the wet friction material according to the first modification of the second embodiment also corresponds to the wet friction material according to the invention of claim 4.

  Furthermore, as shown in FIG. 12 (d), the wet friction material 6C according to the second modification of the second embodiment is used for the wet friction material over the entire surface of the core metal 2 made of a flat plate ring-shaped steel plate. The ring-shaped friction material base material 7 cut out of the normal friction material base material is bonded using an adhesive (thermosetting resin), and both sides are pressed to form an island-shaped portion 8C. It is a ring type friction material formed by forming a plurality (40 on one side) of oil grooves 9C. Here, the left and right outer peripheral corners of the island-like portion 8C are chamfered 8Ca with a height (radial width) of (X1) mm and a length (circumferential width) of 50%. That is, the outer peripheral side of the island-shaped portion 8C is completely cut off from the left and right. And X1 = (3/4) X.

  That is, in the ring-type friction material 6C as the wet friction material according to the second modification of the second embodiment, both the outer peripheral corners of the island-shaped portion 8C sandwiched between the plurality of oil grooves 9C are chamfered. Each of the plurality of oil grooves 9C has a bilaterally symmetric shape, and all the outer peripheral openings of the plurality of oil grooves 9C have a bilaterally symmetric shape and have the width of the narrowest part of the plurality of oil grooves 9C. It spreads over 4 times. Therefore, the ring type friction material 6C according to the second modification of the second embodiment corresponds to the wet friction material according to the inventions of claims 1 and 3.

  Further, the horizontal width of the island-shaped portion 8C and the vertical width of the island-shaped portion 8C are the same dimensions as the segment piece 3 in the segment type friction material 1 according to the first embodiment, that is, the island-shaped portion. The horizontal width of 8C = 13 mm, and the vertical width of the island-shaped portion 8C = 5 mm. Therefore, the ring type friction material 6C as the wet friction material according to the second modification of the second embodiment also corresponds to the wet friction material according to the invention of claim 4.

  Next, a ring type friction material as a wet friction material according to a third modification, a fourth modification, and a fifth modification of the second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 13 (a), the wet friction material 6D according to the third modification of the second embodiment is different from the first embodiment (segment type friction material) in that the core is made of a flat plate ring-shaped steel plate. A ring-shaped friction material base material 7 obtained by cutting a normal friction material base material for wet friction material is bonded to both surfaces of the gold 2 using an adhesive (thermosetting resin), and both surfaces are pressed. It is a ring-type friction material formed by forming a plurality (40 on one side) of oil grooves 9 with the island-like portion 8 interposed therebetween by processing.

  Here, the ring type friction material 6D according to the third modification of the second embodiment is different from the ring type friction material 6 according to the second embodiment shown in FIGS. 12 (a) and 12 (b). In the ring type friction material 6, the positions where the island-like portions 8 are formed in the circumferential direction on the front surface side and the back surface side of the core metal 2 are substantially the same, and therefore the oil groove 9 in the circumferential direction is formed. Whereas the positions are almost the same on the front and back sides, in the ring type friction material 6D, the positions where the island-shaped portions 8 are formed in the circumferential direction on the front surface side and the back surface side of the core metal 2 are shifted. Therefore, the position of the oil groove 9 in the circumferential direction is also shifted on the front and back sides.

  That is, the position where the island-shaped portion 8 is formed in the circumferential direction and the position of the oil groove 9 may be random on the front and back of the cored bar 2, and the ring type shown in FIGS. 12 (a) and 12 (b). The front and back surfaces of the core metal 2 may coincide with each other as in the friction material 6, or the front and back surfaces of the core metal 2 may deviate like the ring type friction material 6 </ b> D shown in FIG. The same applies to other ring type friction materials described in the second embodiment.

  Next, as shown in FIG. 13B, the ring-type friction material 6E according to the fourth modification of the second embodiment is the second modification of the second embodiment shown in FIG. The island-shaped portion 8C of the ring-type friction material 6C according to the example has a reverse outer peripheral shape. That is, the island-shaped portion 8C of the ring-type friction material 6C has a convex shape on the outer peripheral side, whereas the island-shaped portion 8D of the ring-type friction material 6E has a width dmm that is recessed with respect to the outer peripheral side. 8 d of recesses. Further, chamfering 8Da is applied to the left and right outer corners of the island portion 8D.

  The island-shaped portion 8D is larger in height (radial width) and length (circumferential width) than the above-described island-shaped portion 8 and the like, and therefore the number of oil grooves 9D is 30 on the entire circumference. It is less than the book and the ring type friction material 6 described above. All of the plurality of oil grooves 9D have a symmetrical shape, and all the outer peripheral openings of the plurality of oil grooves 9D have a symmetrical shape and are four times or more the width of the narrowest portion of the plurality of oil grooves 9D. It spreads to the width. Therefore, the ring type friction material 6E according to the fourth modification of the second embodiment corresponds to the wet friction material according to the inventions of claims 1, 3 and 5.

  Further, as shown in FIG. 13 (c), a ring type friction material 6F as a wet friction material according to the fifth modification of the second embodiment is wetted on a metal core 2 made of a steel plate having a flat ring shape. The ring-shaped friction material base material 10 cut out from a normal friction material base material for the friction material is bonded using an adhesive (thermosetting resin), and both sides are pressed to form an island-shaped portion. A plurality of (40 on one side) oil grooves 9E and 9F are formed with 8E and 8F interposed therebetween. The island-like portions 8E and 8F are larger in height (radial width) than the above-described island-like portions 8 and the like, but have the same length (circumferential width). The number of 9E and 9F is 40 on the entire circumference, which is the same as that of the ring-type friction material 6 described above.

  Here, the right outer peripheral corner of the island-shaped portion 8E is chamfered 8Ea over almost the entire outer peripheral side of the island-shaped portion 8E, and the left outer peripheral corner of the island-shaped portion 8F is Chamfering 8Fa is performed over substantially the entire outer peripheral side of the island-shaped portion 8F. Therefore, the ring type friction material 6F as the wet friction material according to the fifth modification of the second embodiment corresponds to the wet friction material according to the inventions of claims 1 and 2.

  Next, a ring type friction material as a wet friction material according to a sixth modification, a seventh modification, and an eighth modification of the second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 14 (a), the wet friction material 6G according to the sixth modification of the second embodiment is generally used for a wet friction material on both surfaces of a core metal plate 2 made of a flat ring metal plate. The ring-shaped friction material base material 10 cut out from the friction material base material is bonded using an adhesive (thermosetting resin), and both sides are pressed to form island portions 8E, 8F, 8G. , 8H and a plurality of (40 on one side) oil grooves 9E, 9G, 9H, 9J.

  Here, chamfering 8Ga is applied to the right outer peripheral corner of the island-shaped portion 8G, and chamfering 8Ha is applied to the left outer peripheral corner of the island-shaped portion 8H. Therefore, the ring type friction material 6G as the wet friction material according to the sixth modification of the second embodiment in which the island-shaped portions 8E, 8F, 8G, and 8H are formed is the invention of claims 1 and 2. It corresponds to the wet friction material concerned.

  Further, as shown in FIG. 14B, the ring type friction material 6H as the wet friction material according to the seventh modification of the second embodiment is the entire surface of both surfaces of the core metal 2 made of a flat plate ring-shaped steel plate. In addition, the ring-shaped friction material base material 10 cut out of a normal friction material base material for wet friction material is bonded using an adhesive (thermosetting resin), and both sides are pressed, A plurality (40 on one side) of oil grooves 9K are formed with an island-shaped portion 8F interposed therebetween. Therefore, the ring-type friction material 6H as the wet friction material according to the seventh modification of the second embodiment corresponds to the wet friction material according to the invention of claim 1.

  Further, as shown in FIG. 14 (c), the ring type friction material 6J as the wet friction material according to the eighth modification of the second embodiment is the entire surface of both surfaces of the core metal 2 made of a flat plate ring-shaped steel plate. In addition, the ring-shaped friction material base material 10 cut out of a normal friction material base material for wet friction material is bonded using an adhesive (thermosetting resin), and both sides are pressed, A plurality of (40 on one side) oil grooves 9G, 9L are formed with island-like portions 8F, 8G interposed therebetween. Therefore, the ring type friction material 6J as the wet friction material according to the eighth modification of the second embodiment corresponds to the wet friction material according to the invention of claim 1.

  As a result, when the ring-type friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, and 6J according to the second embodiment are incorporated in the AT, they idle in either direction in the non-fastened state. When the specification is such that the lubricating oil (ATF) is not supplied from the inner peripheral side, the ATF supplied from the outer peripheral side is chamfered parts 8a, 8Aa, 8Ba, 8Ca, 8Da, 8Ea, 8Fa, 8Ga, It is blocked by 8Ha and overflows to the surface of the island-shaped portions 8, 8A, 8B, 8C, 8D, 8E, 8F, 8G, 8H, and ring type friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G , 6H, 6J and the separator plate, the ring type friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, 6J are smoothly idled.

  Also, in the case of the specification in which lubricating oil (ATF) is supplied from the inner peripheral side, there is a space where ATF flows on the outer periphery of the ring type friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, 6J. Since it is sufficient, it is possible to reliably prevent a situation where an oil reservoir is generated on the outer periphery and drag torque is increased.

  Thus, in the ring type friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, and 6J as the wet friction materials according to the second embodiment, the lubricating oil is supplied from the inner peripheral side. Even in the case where there is no specification (without shaft center lubrication), or when the oil accumulation is generated on the outer periphery and the stirring torque is increased, the effect of reducing the drag torque can be obtained more reliably.

  Further, in the ring type friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, and 6J as the press type friction material according to the second embodiment, the entire surface of both sides of the flat plate ring-shaped cored bar 2 is provided. Since it is manufactured by bonding the ring-shaped friction material bases 7 and 10 using an adhesive (thermosetting resin) and pressing both sides, mass production is easier and lower cost. There is an advantage that can be made.

  In each of the above embodiments, only the segment type friction material and the ring type friction material press type friction material among the wet friction materials have been described. However, the ring type cutting type friction in which similar oil grooves are formed by cutting. Also in the material, the drag torque reducing effect equivalent to that of the ring type (press type) friction materials 6, 6A, 6C can be obtained.

  In the above embodiments, as shown in FIGS. 1, 3, 5, 5, 6, 8, and 11 to 14, the segment pieces 3, 3A, 3B, 3C, 3D, 3E, Although the wet friction material in which the 3F, 3G, 3H, 3J, 3K, 3L, 3M, 3N or the ring-shaped friction material bases 7 and 10 are attached only to the portion offset to the outer peripheral side of the core metal 2 has been described. As shown in Patent Document 1 to Patent Document 4, even if a segment piece or a ring-shaped friction material base material is attached with a width of 90% or more of the width from the outer periphery to the inner periphery of the core metal 2, The same drag torque reduction effect as in each embodiment can be obtained.

  In addition, even if a segment piece or a ring-shaped friction material base material is attached with a width of what percentage of the width from the outer periphery to the inner periphery of the cored bar 2, the same drag torque reduction effect as in the above embodiments is obtained. be able to. Furthermore, in each said embodiment, although the case where the segment piece or the ring-shaped friction material base material was affixed on both surfaces of the metal core 2 was explained, depending on the specification, the segment piece or only on one surface of the metal core 2 You may affix a ring-shaped friction material base material.

  Furthermore, in each of the above-described embodiments, when 30 or 40 segment pieces are attached to one side of the core metal 2 and 30 or 40 oil grooves are attached by attaching a ring-shaped friction material base material. However, the number of segment pieces per one side of the cored bar 2 is not limited to 30 or 40, and the number of oil grooves is not limited to 30 or 40. There is no limit to how many or how many.

  In carrying out the present invention, the configuration, shape, quantity, material, size, connection relationship, manufacturing method, etc. of the other parts of the wet friction material (segment type friction material and ring type friction material) are described above. It is not limited to the form. In addition, since the numerical value quoted in the embodiment of the present invention does not indicate a critical value but indicates a preferable value suitable for implementation, even if the numerical value is slightly changed, the implementation is denied. is not.

FIG. 1A is a partial plan view showing a part of a wet friction material (Example 1) according to Embodiment 1 of the present invention, and FIG. 1B shows a first modification of Embodiment 1 of the present invention. The partial top view which showed a part of wet wet friction material (Example 2) which concerns, (c) shows a part of wet friction material (Example 3) which concerns on the 2nd modification of Embodiment 1 of this invention. FIG. FIG. 2A is a partial cross-sectional view showing a longitudinal section of the wet friction material (Example 1) according to Embodiment 1 of the present invention, and FIG. 2B is a third modification of Embodiment 1 of the present invention. It is the fragmentary sectional view which showed the longitudinal cross-section of the wet friction material which concerns. 3 (a) and 3 (b) are partial plan views showing a part of a wet friction material according to another modification of the first embodiment of the present invention. 4 (a), (b), (c), (d), (e), and (f) are the shapes of the segment pieces used in the wet friction material according to another modification of the first embodiment of the present invention. FIG. FIG. 5A is a partial plan view showing a part of a wet friction material according to a fourth modification of the first embodiment of the present invention, and FIG. 5B shows a fifth modification of the first embodiment of the present invention. The partial top view which showed a part of the wet friction material which concerns, (c) is the partial top view which showed a part of wet friction material which concerns on the 6th modification of Embodiment 1 of this invention, (d) is this The partial top view which showed a part of wet friction material which concerns on the 7th modification of Embodiment 1 of invention, (e) is a part of wet friction material which concerns on the 8th modification of Embodiment 1 of this invention. It is the fragmentary top view which showed. 6A is a partial plan view showing a part of the wet friction material according to the first example of the prior art (Comparative Example 1), and FIG. 6B is a wet friction material according to the second example of the prior art (Comparative Example). 2) is a partial plan view showing a part of (2), and (c) is a partial plan view showing a part of a wet friction material (Comparative Example 3) according to a third example of the prior art. FIG. 7 compares the relationship between the relative rotational speed and drag torque of the wet friction material according to the first embodiment of the present invention (Examples 1, 2, and 3) with that of the conventional wet friction material (Comparative Examples 1, 2, and 3). It is a figure shown. FIG. 8 is a diagram showing the relationship between parameters in the wet friction material (Example 1) according to Embodiment 1 of the present invention. FIG. 9 is a diagram showing the relationship between the cutting height (width in the radial direction) of the outer peripheral corner portion of the oil groove and the drag torque reduction rate in the wet friction material (Example 1) according to Embodiment 1 of the present invention. FIG. 10 is a diagram showing the relationship between the cut length (circumferential width) of the outer peripheral corner portion of the oil groove and the drag torque reduction rate in the wet friction material (Example 1) according to Embodiment 1 of the present invention. . FIG. 11A is an explanatory view showing the generation of drag torque in a conventional wet friction material (Comparative Example 1), and FIG. 11B is the drag torque in the wet friction material (Example 1) according to Embodiment 1 of the present invention. It is explanatory drawing which shows the reduction effect. 12 (a) is a partial plan view showing a part of the wet friction material according to Embodiment 2 of the present invention, and FIG. 12 (b) shows a longitudinal section of the wet friction material according to Embodiment 2 of the present invention. Partial sectional view, (c) is a partial plan view showing a part of a wet friction material according to a first modification of the second embodiment of the present invention, and (d) is a second modification of the second embodiment of the present invention. It is the fragmentary top view which showed a part of wet friction material which concerns on an example. FIG. 13 (a) is a partial sectional view showing a longitudinal section of a wet friction material according to a third modification of the second embodiment of the present invention, and FIG. 13 (b) is a fourth modification of the second embodiment of the present invention. (C) is a partial plan view showing a part of the wet friction material according to the fifth modification of the second embodiment of the present invention. 14 (a) is a partial plan view showing a part of a wet friction material according to a sixth modification of the second embodiment of the present invention, and FIG. 14 (b) is a seventh modification of the second embodiment of the present invention. (C) is a partial plan view showing a part of the wet friction material according to the eighth modification of the second embodiment of the present invention.

Explanation of symbols

1, 1A, 1C, 1D, 1E, 1F, 1G, 1H, 1J, 1K, 1L, 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, 6J Wet friction material 2 Core metal 3, 3A, 3B , 3C, 3D, 3E, 3F, 3G, 3H, 3I, 3J, 3K, 3L, 3M, 3N Segment piece 3a, 3Aa, 3Ba, 3Ca Notch (chamfering)
3g, 3h, 3i, 3j, 8d Recess 4, 4A, 4B, 4C, 4D, 4E, 4F, 4G, 4H, 4J, 4K, 4L, 4M, 9, 9A, 9B, 9C, 9D, 9E, 9F, 9G, 9H, 9J, 9K, 9L Oil groove 7, 10 Ring-shaped friction material base 8, 8A, 8B, 8C, 8D, 8E, 8F, 8G, 8H Island-like portions 8a, 8Aa, 8Ba, 8Ca, 8Da , 8Ea, 8Fa, 8Ga, 8Ha Chamfering

Claims (5)

A friction material base material cut into segment pieces along the flat plate ring shape is bonded to a flat plate ring-shaped cored bar, and a plurality of pieces in the radial direction are adhered to each other by gaps between the adjacent segment pieces. Segment type friction material with oil grooves formed, or a ring-shaped friction material base material is bonded to both sides or one side of a flat ring-shaped cored bar and pressed or cut to leave an island-shaped portion, and then in the radial direction A ring type friction material in which a plurality of oil grooves are formed,
One type or both of the said segment piece pinched | interposed into the said some oil groove or the outer peripheral side corner | angular part of the said island-shaped part were R-processed or chamfered, The wet friction material characterized by the above-mentioned.   All of the plurality of oil grooves have a symmetrical shape, and at least every two of the plurality of oil grooves, the outer peripheral openings are symmetrical, and the width of the narrowest part of the plurality of oil grooves is 4 2. The wet friction material according to claim 1, further comprising an oil groove extending to a width of at least twice.   All of the plurality of oil grooves have a symmetrical shape, and all the outer peripheral openings of the plurality of oil grooves have a symmetrical shape and are at least four times the width of the narrowest portion of the plurality of oil grooves. The wet friction material according to claim 1, wherein the wet friction material extends in a width.   The circumferential width of the R processing or the chamfering processing is 3 mm or more, or 15% or more of the circumferential width of the segment piece or the island portion, and the circumferential direction of the segment piece or the island portion is 50% or less of the width and at least three times the width of the narrowest portion of the plurality of oil grooves, the radial width of the R processing or the chamfering processing is the segment piece or the island-shaped portion The wet friction material according to any one of claims 1 to 3, wherein the wet friction material is within a range of 20% to 100% of a width in the radial direction.   Furthermore, the recessed part dented with respect to the outer peripheral side was provided in the outer peripheral side center part of the said segment piece or the said island-shaped part pinched | interposed into these oil grooves. The wet friction material as described in any one.

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