JP4345486B2 - Pulley device - Google Patents

Description

  The pulley device according to the present invention includes, for example, a mechanism for driving an auxiliary machine such as a compressor used in an air conditioner for an automobile by an endless belt, or a crank pulley and a cam fixed to an end of a crankshaft by a timing belt. It is used as a guide pulley or tension pulley that is used by being incorporated in a belt transmission mechanism such as a mechanism for transmitting rotational force to and from a cam pulley fixed to the end of the shaft.

As a pulley device such as a guide pulley or a tension pulley that is incorporated in a belt transmission mechanism, a pulley device in which a synthetic resin pulley is fixed to an outer ring of a rolling bearing has been conventionally used in order to reduce weight and cost. in use. FIG. 6 shows a pulley apparatus 1 incorporating a synthetic resin pulley described in, for example, Patent Document 1 and conventionally known. This pulley apparatus 1 is a rolling roller which is a single-row deep groove type radial ball bearing for rotatably supporting a pulley on a support shaft or the like, and a synthetic resin pulley 2 for belting the outer peripheral surface. And a bearing 3. Among these, the rolling bearing 3 includes an inner ring 5 having a single row inner ring raceway 4 on an outer peripheral surface, an outer ring 7 having a single row outer ring raceway 6 on an inner peripheral surface, and a space between the inner ring raceway 4 and the outer ring raceway 6. And a plurality of rolling elements (balls) 8 provided so as to be freely rollable. Further, sealing plates 9 and 9 are provided between the outer peripheral surfaces of both ends of the inner ring 5 and the inner peripheral surfaces of both ends of the outer ring 7, and grease filled in the space where the rolling elements 8 are installed leaks to the outside. In addition to preventing external dust and the like from entering this space. The pulley 2 is fixed on the outer diameter side of the outer ring 7 of the rolling bearing 3 configured in this manner so as to cover the outer peripheral surface of the outer ring 7 and the portions near the outer diameter of both end surfaces in the axial direction . .

The pulley 2 has an inner diameter side cylindrical portion 10 and an outer diameter side cylindrical portion 11 provided concentrically with each other. The outer peripheral surface of the intermediate portion of the inner diameter side cylindrical portion 10 and the inner peripheral surface of the intermediate portion of the outer diameter side cylindrical portion 11 are connected by a ring-shaped connecting portion 12, and a plurality of both are provided on both side surfaces of the connecting portion 12. The reinforcing ribs 13 and 13 are provided radially. In such a pulley 2, the inner diameter side cylindrical portion 10 is fixed around the outer ring 7 constituting the rolling bearing 3 by injection molding. That is, with the outer ring 7 closer to the outer diameter , the molten thermoplastic resin is injected into a cavity having an inner shape corresponding to the outer shape of the pulley 2 provided in the mold in a state where the outer ring 7 is molded on the inner peripheral side. To do. After the thermoplastic resin has cooled and solidified, the mold is opened, and the pulley 2 is taken out of the cavity together with the rolling bearing 3 from the cavity.

  The pulley apparatus 1 configured as described above is used as, for example, a guide pulley or a tension pulley incorporated in a belt transmission mechanism that drives an auxiliary machine of an automobile. That is, the inner ring 5 constituting the rolling bearing 3 is externally fitted and fixed to a support shaft fixed to a fixed part such as a cylinder block of the engine. Then, an endless belt is stretched around the outer peripheral surface of the pulley 2. In this state, the pulley device 1 rotates the pulley 2 as the endless belt travels, and ensures the winding angle of the endless belt or the tension of the endless belt.

As described above, in the case of the pulley device 1 in which the synthetic resin pulley 2 is fixed to the outer diameter side of the outer ring 7, the outer ring 7 is made of a metal material such as bearing steel. And the linear expansion coefficient are different. Therefore, due to a temperature rise during use, the adhesion between the outer ring 7 and the pulley 2 may be reduced, and a relative slip (creep) may occur between the outer ring 7 and the pulley 2. As a technique for preventing such creep, a structure in which a concave groove is formed on the outer peripheral surface of an outer ring has been conventionally known as described in, for example, Patent Documents 2 to 3.

  FIG. 7 shows a first example of a conventional structure described in Patent Document 2 for preventing creep. In this structure, the inclined groove 14 inclined with respect to the circumferential direction is formed in a spiral shape on the outer peripheral surface of the outer ring 7a, and the parallel groove 15 parallel to the circumferential direction is formed. Then, a part of the synthetic resin constituting the pulley 2a disposed around the outer ring 7a is caused to enter and solidify into the inclined concave groove 14 and the parallel concave groove 15, so that a ridge is formed on the inner peripheral surface of the pulley 2a. 16 and 16a are formed, and the protrusions 16 and 16a are engaged with the inclined grooves 14 and the parallel grooves 15. Of these, the inclined groove 14 is inclined with respect to the circumferential direction, so that creep occurs between the outer ring 7a and the pulley 2a due to the engagement between the side surface of the inclined groove 14 and the protrusion 16. Can be prevented.

  FIG. 8 shows a second example of a conventional structure described in Patent Document 3 for preventing creep. In this structure, an endless inclined groove 14a is formed on the outer peripheral surface of the outer ring 7b in a state inclined with respect to the circumferential direction. Also in this structure, the protrusion formed on the inner peripheral surface of the pulley at the time of injection molding is engaged with the inclined groove 14a. The inclined concave groove 14a is inclined with respect to the circumferential direction, and the depth and width gradually change in the circumferential direction. For this reason, creep occurs between the outer ring 7b and the pulley due to the meshing of the side surface and bottom surface of the inclined groove 14a with the side surface and tip surface of the ridge formed on the inner peripheral surface of the pulley. Can be prevented.

  In the structure shown in FIGS. 7 and 8 described above, when the pulley 2a tends to rotate with respect to the outer rings 7a and 7b in order to prevent creep by engagement between the inclined grooves 14 and 14a and the protrusions, the inclined grooves A component force in the axial direction acts on the outer rings 7a and 7b based on the pressing of the inner side surfaces of the grooves 14 and 14a and the side surfaces of the protrusions. A moment load may act on the outer rings 7a and 7b based on this component force. That is, in the case of the structure shown in FIG. 7, the axis of the outer ring 7a in the inclined groove 14 is not set unless the start point and the end point of the inclined groove 14 are completely coincided with each other in the circumferential direction of the outer ring 7a. The number of overlapping portions with respect to the direction is different from each other with respect to the circumferential direction. Since the magnitude of the force acting in the axial direction per unit length of the inclined concave groove 14 is considered to be the same, the component force acting in the axial direction of the outer ring 7a depends on the number superimposed in the axial direction. Different. Therefore, unless the starting point and the ending point of the inclined groove 14 are completely coincident with each other in the circumferential direction, the component forces acting in the axial direction on the outer ring 7a are different from each other in the circumferential direction. The corresponding moment load is applied.

  In the structure described in Patent Document 2, in addition to the inclined concave groove 14, a parallel concave groove 15 parallel to the circumferential direction of the outer ring 7a is formed on the outer peripheral surface of the outer ring 7a, and is added to the outer ring 7a. Axial force is supported. However, as long as the moment load itself is not prevented, the contact portion between the inner side surface of the parallel groove 15 and the side surface of the ridges 16 and 16a formed on the inner peripheral surface of the pulley 2a made of synthetic resin is used. Repeated pressing force is applied. As a result, with use over a long period of time, the ridges 16, 16a formed on the inner peripheral surface of the pulley 2a, the inclined concave grooves 14 and the parallel concave grooves 15 formed on the outer peripheral surface of the outer ring 7a, There is a possibility that a gap is formed in the engaging portion of the inner wheel, and the pulley 2a rattles against the outer ring 7a. On the other hand, in the structure described in Patent Document 3, the moment load applied to the outer ring 7b is supported based on the engagement between the endless inclined concave groove 14a and the protrusion formed on the inner peripheral surface of the pulley. Since the parallel concave grooves are not formed, the problem as described above becomes more remarkable.

JP-A-10-122339 Japanese Utility Model Publication No. 58-35013 JP 2003-65424 A

  In view of the circumstances as described above, the present invention is designed to prevent a moment load from being generated on the outer ring and the pulley, and to realize a structure capable of sufficiently preventing the creep generated between the outer ring and the pulley. It is what.

The pulley apparatus of the present invention includes an inner ring, an outer ring, a plurality of rolling elements, and a synthetic resin pulley, as in the conventional structures described above.
Of these, the inner ring has an inner ring raceway on the outer peripheral surface.
The outer ring has an outer ring raceway on the inner peripheral surface.
Each of the rolling elements is provided between the inner ring raceway and the outer ring raceway so as to be freely rollable.
Further, the pulley is fixed to the outer diameter side of the outer ring in a state of covering the outer peripheral surface of the outer ring and the portions near the outer diameter of both end faces in the axial direction .
Then, by causing a part of the synthetic resin constituting the pulley to enter the inclined groove formed in the outer circumferential surface of the outer ring in a state inclined with respect to the circumferential direction, relative rotation between the pulley and the outer ring is caused. Blocking.
In particular, in the pulley device of the present invention, each of the outer ring outer peripheral surfaces near the axial ends is formed so as not to open to the axial end surface of the outer ring, each of which is parallel to the circumferential direction. With a pair of parallel grooves. And the above-mentioned inclined ditch is formed in a spiral shape only between these two parallel ditches in a state where both ends thereof are continuous with the middle part of these both parallel ditch, and the number of turns is an integer, The width dimension of the both parallel grooves is larger than the width dimension of the inclined grooves .

In the case of the pulley device of the present invention configured as described above, moment load is prevented from being generated in the outer ring and the pulley, and creep generated between the outer ring and the pulley can be sufficiently prevented.
That is, since the spiral inclined groove is formed on the outer peripheral surface of the outer ring, the creep preventing function can be exhibited over the entire periphery. As a result, the occurrence of creep can be sufficiently prevented. Since the number of turns of the inclined groove (the number of turns of the outer peripheral surface of the outer ring) is an integer, the number of grooves that overlap in the axial direction among the inclined grooves is the same over the entire circumference. Accordingly, the magnitude of the component force applied in the axial direction based on the engagement between the inclined concave groove and the protrusion formed on the inner peripheral surface of the pulley is the same over the entire circumference. For this reason, even if the outer ring and the pulley tend to rotate relative to each other, a moment load is not applied to the outer ring and the pulley.

In the case of the present invention, since a pair of parallel concave grooves are formed near the both axial ends of the outer peripheral surface of the outer ring, for example, the friction coefficient of the engaging portion between the inclined concave groove and each protrusion is determined. Even if the moment load and the axial load cannot be completely canceled due to the difference or the like, these loads can be effectively supported, and the strength and rigidity of the joint between the outer ring and the pulley can be further increased. Further, the both parallel concave grooves improve the axial positioning accuracy of the outer ring with respect to the pulley. Further, in the case of the present invention, since both end portions of the inclined groove and the intermediate portion of the both parallel grooves are continuous, when forming these grooves, the position of the tool is reset in the middle. It can be processed in one process without any problems. For this reason, the processing cost can be kept low.
Further, in the case of the present invention, the both parallel grooves are formed in a portion close to both axial ends of the outer peripheral surface of the outer ring so as not to open to the axial end surface of the outer ring, Since the width dimension is made larger than the width dimension of the inclined groove, the effect of increasing the strength and rigidity of the coupling portion between the outer ring and the pulley becomes remarkable.

In order to carry out the present invention, the number of turns of the inclined groove is preferably 3 or more.
If comprised in this way, the engagement part of a sloping groove and the protrusion formed in the internal peripheral surface of a pulley will increase, and a creep prevention function can be improved more.

1 and 2 show an embodiment of the present invention. The outer ring 7c incorporated in the present embodiment is formed with inclined concave grooves 14b and parallel concave grooves 15a and 15a on the outer peripheral surface thereof. Of these, the inclined groove 14b is formed in a spiral shape, and the number of turns (the number of times the inclined groove 14b circulates around the outer peripheral surface of the outer ring 7c) is an integer of three. For this reason, the start point P ₁ and the end point P _{2 of the} inclined groove 14b exist at the same position with respect to the circumferential direction of the outer peripheral surface of the outer ring 7c. In the case of the present embodiment, the parallel concave grooves 15a, 15a parallel to the circumferential direction are formed near both axial ends of the outer peripheral surface of the outer ring 7c. And the both ends of the said inclined ditch | groove 14b are made to continue to the intermediate part of both these parallel ditch | grooves 15a and 15a, respectively. Accordingly, each of these parallel concave grooves 15a, 15a is formed at a position aligned with the start point P ₁ and the end point P _{2 in} the axial direction of the outer ring 7c.

In addition, it is preferable that the bus | bath shape of the said inclination ditch | groove 14b and each said parallel ditch | groove 15a, 15a shall be circular arc shape, respectively. Thereby, in the vicinity of the portion where the inclined groove 14b and the parallel grooves 15a and 15a are continuous, the portion existing between the grooves 14b and 15a is less likely to be damaged. Yield can be improved. Moreover, the width dimension of each said parallel ditch | groove 15a, 15a is larger than the said inclination ditch | groove 14b. Further, as shown in FIG. 3, the depth of the inclined concave groove 14b is h, the diameter of the groove bottom is a, the outer diameter of the outer ring 7c is D, the diameter of the groove bottom of the outer ring raceway 6 is b, each rolling element. When the diameter of 8 is d, the depth h of the inclined groove 14b may be regulated so that h / D ≧ 0.0072 and (ab) /d≧0.343. preferable.

  As described above, the pulley 2a made of synthetic resin (see FIG. 7) is formed around the outer ring 7c having the inclined grooves 14b and the parallel grooves 15a and 15a formed on the outer peripheral surface, as in the case of the conventional structure described above. ) Is injection molded. That is, the outer ring 7c is set in a mold for injection molding of synthetic resin with the outer peripheral surface exposed to the inner peripheral surface portion of the cavity, and the synthetic resin is fed into the cavity. As a result, a part of the synthetic resin fed into the cavity enters the inclined grooves 14b and the parallel grooves 15a and 15a, and is cooled and solidified in the grooves 14b and 15a. Become. In this way, the outer ring 7c having the pulley 2a made of synthetic resin fixed to the outer diameter side is combined with the plurality of rolling elements 8, 8 and the inner ring 5 (see FIG. 7) to form a pulley device.

As the synthetic resin constituting the pulley 2a, polyamide resins such as polyamide 6, polyamide 66, polyamide 46, and polyamide 612, polyphenylene sulfide, phenol resin, and the like can be used. Moreover, glass fiber, carbon fiber, or the like is used as a reinforcing fiber mixed with such a synthetic resin. The ratio of mixing the reinforcing fibers is 10 to 60% by mass, preferably 20 to 50% by mass. The linear expansion coefficient of the synthetic resin mixed with the reinforcing fibers is 5 × 10 ⁻⁵ or less, and the flexural modulus is 5 GPa or more. Is preferable. In addition, when the ratio which mixes the said reinforcement fiber shall be less than 10 mass%, rigidity will fall while the linear expansion coefficient of a synthetic resin becomes large too much. As a result, creep tends to occur, which is not preferable. Further, when the proportion of the reinforcing fibers mixed is more than 60% by mass, the fluidity at the time of injection molding is deteriorated and molding defects are likely to occur, which is not preferable.

In the present embodiment configured as described above, moment load is prevented from being generated in the outer ring 7c, and creep generated between the outer ring 7c and the pulley 2a can be sufficiently prevented. That is, since the spiral inclined groove 14b is formed on the outer peripheral surface of the outer ring 7c, the creep preventing function can be exhibited over the entire periphery. As a result, the occurrence of creep can be sufficiently prevented. Further, since the number of turns of the inclined concave groove 14b is an integer, the number of grooves overlapping in the axial direction among the inclined concave grooves 14b is the same over the entire circumference. In other words, unless the number of turns of the inclined groove 14b is an integer, the number of grooves overlapping in the axial direction is not the same over the entire circumference. For example, as shown in FIGS. 4 to 5, when the inclined groove 14 c is rotated 2.5 times (2 and a half), the start point P ₁ ′ and the end point P ₂ ′ are shifted by a half around the circumferential direction of the outer ring 7 c. Will exist at each position. In this case, as is apparent from FIGS. 4 to 5, the number of grooves overlapping in the axial direction among the inclined concave grooves 14 c formed on the outer peripheral surface of the outer ring 7 c is different in the circumferential direction of the outer ring 7 c. . Specifically, the number of grooves overlapping in the axial direction is three in the upper half of FIGS. 4 to 5 and two in the lower half.

  As described above, if the number of grooves overlapping in the axial direction is different in the circumferential direction, it is applied in the axial direction based on the engagement between the inclined concave groove 14c and the protrusion formed on the inner peripheral surface of the pulley 2a. The magnitude of the component force differs in the circumferential direction. In the illustrated example, the upper half of the outer ring 7c has a larger number of grooves overlapping in the axial direction, so that the component force applied to the upper half is greater than that of the lower half. A moment load is generated in the outer ring 7c and the pulley 2a due to the difference in component force. On the other hand, as in this embodiment, when the number of turns of the inclined groove 14b is an integer, this is based on the engagement between the inclined groove 14b and the protrusion formed on the inner peripheral surface of the pulley 2a. Therefore, even if the outer ring 7c and the pulley 2a tend to rotate relative to each other, a moment load is applied to the outer ring 7c and the pulley 2a. There will be no participation. The number of turns of the inclined concave groove 14b may be an integer, but it is preferably 3 times or more in order to further improve the creep prevention function. Further, if the depth h of the inclined concave groove 14b is restricted as described above, the creep prevention function can be further improved and the strength of the outer ring 7c can be sufficiently secured.

In the case of the present embodiment, since the parallel concave grooves 15a and 15a are formed on the outer peripheral surface of the outer ring 7c, for example, due to the difference in the friction coefficient of the engaging portion between the inclined concave groove 14b and each protrusion. Even if the moment load and the axial load cannot be completely canceled, these loads can be effectively supported to increase the strength and rigidity of the joint between the outer ring 7c and the pulley 2a. The parallel concave grooves 15a and 15a improve the axial positioning accuracy of the outer ring 7c with respect to the pulley 2a. Moreover, since the width dimension of the said parallel ditch | groove 15a, 15a is made larger than the width dimension of the said inclination ditch | groove 14b, the effect which raises the intensity | strength and rigidity of the said connection part becomes remarkable.

  Furthermore, in the case of the present embodiment, since both end portions of the inclined groove 14b and the parallel grooves 15a, 15a are made continuous, the position of the tool is halfway when forming these grooves 14b, 15a. Processing can be performed in a single process without re-setting. For this reason, the processing cost can be kept low. That is, first, a parallel groove 15a parallel to the circumferential direction is formed on one end of the outer ring 7c. Next, the inclined groove 14b is processed by inclining the direction in which the tool advances so as to branch from a part of the circumferential direction of the parallel groove 15a. Then, the parallel concave groove 15a on the other end side of the outer ring 7c is formed by making the direction in which the tool advances parallel to the circumferential direction from the end that is the end point of the inclined concave groove 14b. . Thus, in the case of the present embodiment, the inclined groove 14b and the parallel grooves 15a, 15a can be continuously processed on the outer peripheral surface of the outer ring 7c without resetting the position of the tool. Cost can be kept low.

1 is a perspective view showing Example 1 of the present invention with only an outer ring taken out. FIG. The figure seen from the outer diameter side of FIG. The figure which shows the partial cross section figure of the outer ring which formed the inclined ditch | groove in the outer peripheral surface in the state which installed the rolling element in the outer ring track. The perspective view which takes out only an outer ring | wheel and shows an example which is not preferable. The figure seen from the outer diameter side of FIG. The partial cutaway perspective view of the pulley apparatus of conventional structure. The fragmentary sectional view which shows the 1st example of the conventional structure for preventing creep. The figure which looked at the outer ring | wheel from the outer-diameter side which shows the 2nd example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pulley apparatus 2, 2a Pulley 3 Rolling bearing 4 Inner ring track 5 Inner ring 6 Outer ring track 7, 7a, 7b, 7c Outer ring 8 Rolling element 9 Sealing plate 10 Inner diameter side cylindrical part 11 Outer diameter side cylindrical part 12 Connection part 13 Reinforcement rib 14 , 14a, 14b, 14c Inclined groove 15, 15a Parallel groove 16, 16a

Claims (2)

An inner ring having an inner ring raceway on the outer peripheral surface, an outer ring having an outer ring raceway on the inner peripheral surface, a plurality of rolling elements provided so as to roll between the inner ring raceway and the outer ring raceway, and an outer peripheral surface of the outer ring And a synthetic resin pulley fixed to the outer diameter side of the outer ring in a state of covering a portion near the outer diameter of both end faces in the axial direction , and formed on the outer peripheral surface of the outer ring in an inclined state with respect to the circumferential direction. In a pulley apparatus that prevents relative rotation between the pulley and the outer ring by allowing a portion of the synthetic resin that constitutes the pulley to enter the inclined concave groove, a portion closer to both axial ends of the outer peripheral surface of the outer ring And a pair of parallel grooves formed in a state of not opening in the axial end face of the outer ring, each parallel to the circumferential direction, and the inclined grooves are only between these parallel grooves. , Both ends are connected to the middle of both parallel grooves Spirally formed in a state where the number of turns is an integer, the pulley device width of both parallel grooves being greater than the width of the inclined groove.   The pulley apparatus according to claim 1, wherein the number of turns of the inclined concave groove is three or more.

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