JP4969123B2 - Automatic transmission - Google Patents

Description

  The present invention relates to an automatic transmission having a planetary gear mechanism.

  For example, in an automatic transmission employed in an automobile, a forward / reverse switching operation may be performed by a planetary gear mechanism. For example, in Patent Document 1, a carrier that pivotally supports a pinion gear is fixed by a brake so as not to rotate when moving forward, and is connected so as to rotate together with a sun gear by a clutch when moving backward.

  Further, as the carrier, a carrier body that pivotally supports the pinion gear and a clutch holding member that holds the clutch may be integrated by diffusion bonding by sintering (for example, see Patent Document 2).

For example, as shown in FIG. 4, a columnar portion 50a is integrally formed on a carrier 50 that supports a pinion gear (not shown), and a clutch holding member 51 is fitted to an open side end portion 50b of the columnar portion 50a. Can be considered. The rotation of the sun gear 53 is directly transmitted to the carrier 50 by pressing the clutch 54 disposed between the clutch holding member 51 and the sun gear 53 with a piston (not shown). In addition, 55 is a ring gear and 56 is a disc spring.
JP 2002-327828 A JP 2003-13113 A

  By the way, when the above structure is adopted, the piston load P is transmitted from the clutch holding member 51 to the carrier 50 via the columnar portion 50a, and therefore, the piston load is applied to the joint surface 52 between the clutch holding member 51 and the columnar portion 50a. Reaction force will act. As a result, there is a concern that the joint surface 52 is disadvantageous in strength and the setting of the piston load is restricted. Here, it is conceivable to separately provide a support member for supporting the piston load. However, if this is done, there arises a problem that the number of parts and the number of assembly steps increase.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an automatic transmission that can ensure the strength against the piston load without increasing the number of parts and the number of assembly steps.

The present invention includes a sun gear, a ring gear disposed so as to surround the sun gear, a pinion gear disposed between the ring gear and the sun gear, a carrier that pivotally supports the pinion gear, and the carrier and the sun gear. In an automatic transmission having a planetary gear mechanism including a clutch disposed therebetween, the carrier includes a carrier body that pivotally supports the pinion gear, and a columnar portion that is integrally formed with the carrier body and extends toward the clutch. A clutch holding member that is joined to the open side end portion of the columnar portion and holds the clutch, and the columnar portion of the bottom side of the clutch holding member is joined to the open side end surface of the columnar portion. projecting the clutch side of the part,
A disc spring that urges the clutch in the release direction between the clutch holding member and the clutch, an inner peripheral portion of which is in contact with the open side end surface, and an outer peripheral portion of the bottom surface of the clutch holding member, The columnar part is disposed so as to be inclined away from the joined portion, and the piston load acting via the clutch is supported only by the open end surface of the columnar part with the disc spring interposed therebetween. It is said.

  According to the automatic transmission of the present invention, the open side end surface of the columnar portion formed integrally with the carrier body is protruded from the joint bottom surface of the clutch holding member to the clutch side, and the piston load is supported by the protruding open side end surface. Therefore, the piston load is transmitted from the columnar portion to the carrier body without being transmitted to the clutch holding member. As a result, the pressure of the piston load does not act on the joint surface between the columnar portion and the clutch holding member, so that the concern about the strength of the joint surface can be eliminated, and the set value of the piston load can be increased. .

  In addition, since the open side end surface of the columnar part simply needs to protrude from the joint bottom surface of the clutch holding member to the clutch side, the number of parts and the number of assembling steps when separately providing a support member are increased. Absent.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 3 are diagrams for explaining an automatic transmission according to an embodiment of the present invention. FIG. 1 is an overall configuration diagram of the automatic transmission, and FIG. 2 is a cross-sectional view of a planetary gear mechanism of the automatic transmission. FIG. 3 is a cross-sectional view of the main part of the carrier of the planetary gear mechanism.

  In the figure, reference numeral 1 denotes an automatic transmission coupled to a crankshaft horizontal engine (not shown) mounted on an automobile. This automatic transmission 1 includes an input shaft 4 disposed in a three-part casing 2 so as to be coaxial with a crankshaft 3 that outputs engine rotational force, and rotation of the crankshaft 3 to the input shaft 4. A torque converter 9 for transmission, a planetary gear mechanism 5 mounted on the input shaft 4, a belt type continuously variable transmission mechanism 6 for transmitting rotation of the input shaft 4 via the planetary gear mechanism 5, and the continuously variable The structure is such that a differential gear mechanism 7 for transmitting the rotation of the transmission mechanism 6 to the left and right output shafts 8 and 8 is accommodated.

  The torque converter 9 includes a pump impeller 9c coupled to the crankshaft 3, and a turbine liner 9d coupled to the input shaft 4. The crankshaft 3 rotates from the pump impeller 9c to the turbine liner 9d. And transmitted to the input shaft 4. In addition, 9a is a lockup clutch and 9b is a starter gear.

  The belt-type continuously variable transmission mechanism 6 includes a primary shaft 13 disposed so as to be coaxial with the input shaft 4, a secondary shaft 16 disposed in parallel with the primary shaft 13, and a primary sheave of the primary shaft 13. 10 and a V-belt 12 wound around a secondary sheave 11 of the secondary shaft 16.

  The primary sheave 10 includes a fixed sheave 13 a formed integrally with the primary shaft 13, a movable sheave 14 that is mounted on the primary shaft 13 so as to be movable in the axial direction, and the movable sheave 14 to form a hydraulic control chamber 15 a. And a hydraulic plate 15 to be formed.

  The secondary sheave 11 includes a fixed sheave 16 a formed integrally with the secondary shaft 16, a movable sheave 17 that is mounted on the secondary shaft 16 so as to be movable in the axial direction, and the movable sheave 17. And a hydraulic plate 18 to be formed.

  A small reduction gear 16b is splined to the inner end portion of the secondary shaft 16, and the ring gear 7a of the differential gear mechanism 7 is engaged with the reduction small gear 16b. An axle 8b is connected to the left and right output shafts 8, 8 of the differential gear mechanism 7 via a constant velocity joint 8a.

  The planetary gear mechanism 5 performs a forward / reverse switching operation, and includes a sun gear 19 to which the rotational force of the crankshaft 3 is input, a ring gear 20 disposed so as to surround the outer periphery of the sun gear 10, A plurality of pinion gears 21 disposed between the ring gear 20 and the sun gear 19, a carrier 22 that pivotally supports each pinion gear 21, and a clutch 23 disposed between the sun gear 19 and the carrier 22 are provided. The planetary gear mechanism 5 includes a brake 24 that fastens the carrier 22 in a non-rotatable manner or releases the fastening.

  The sun gear 19 is coupled to the input shaft 4 so as to rotate together, and the sun gear 19 is integrally formed with a clutch holding portion 19a extending to the clutch side.

  The ring gear 20 includes an outer peripheral wall portion 20a formed so as to surround the sun gear 19, and a plate portion 20b coupled to the inner end portion 13b of the fixed sheave 13a of the primary shaft 13 so as to rotate together with the primary shaft 13. It has a generally bowl shape.

  The carrier 22 is formed by sintering, a disk-shaped carrier main body 22a having a boss portion 22c rotatably mounted on the outer end portion of the input shaft 4, and the carrier main body 22a to the input shaft. 4, a plurality of columnar portions 22 b integrally formed so as to extend toward the clutch side, and an annular clutch holding member 25 arranged so as to surround the clutch holding portion 19 a of the sun gear 19.

  The clutch holding member 25 has a structure in which a holding portion 25b extending in the input shaft direction is integrally formed with a ring-shaped plate portion 25a. Engagement support portions 25c and 25d for engaging and supporting the friction plates 23a and 24a of the clutch 23 and the brake 24 are formed on the inner peripheral surface and the outer peripheral surface of the holding portion 25b, respectively.

  The sun gear 19 is disposed in a space surrounded by the columnar portions 22b of the carrier body 22a, and a bearing 26 is disposed between the sun gear 19 and the boss portion 22c of the carrier body 22a.

  The carrier body 22a is disposed in the ring gear 20, and a support shaft 27 that supports the pinion gears 21 so as to be relatively rotatable is disposed on the outer periphery of the carrier body 22a at a predetermined interval in the circumferential direction. Each support shaft 27 is fixed to the carrier body 22 a by a pin 28.

  An inner case 30 that rotatably supports the input shaft 4 is disposed upstream of the carrier 22 in the casing 2 in the input direction. The inner case 30 is fixed to the casing 2.

  A clutch piston 31 is disposed in a cylinder chamber formed in the inner case 30 so as to face the clutch 23. The clutch piston 31 is supported by the inner case 30 so as to be slidable in the axial direction of the input shaft 4. A hydraulic chamber 32 is formed by the clutch piston 31 and the cylinder chamber of the inner case 30. By supplying hydraulic pressure to the hydraulic chamber 32, the clutch piston 31 moves in the clutch connecting direction. The clutch piston 31 is supported in a non-rotatable manner, and a slide bearing 33 is disposed on the contact surface of the clutch 23 with the clutch piston 31.

  A brake piston 34 is disposed outside the ring gear 20 in the casing 2 so as to face the brake 24. The brake piston 34 is supported by a cylinder chamber formed in the casing 2 so as to be slidable in the axial direction of the input shaft 4. A hydraulic chamber 35 is formed by the brake piston 34 and the cylinder chamber of the casing 2, and the brake piston 34 moves in the brake fastening direction by supplying hydraulic pressure to the hydraulic chamber 35.

  A return spring 37 is disposed between the front ends of the clutch piston 31 and the brake piston 34. The return spring 37 always urges the pistons 31 and 34 in a direction away from each other, that is, a direction in which the clutch 23 and the brake 24 are released.

  The brake 24 includes a plurality of friction plates 24 a and is disposed between the brake piston 34 and the clutch holding member 25 and the inner case 30 of the carrier 22.

  The clutch 23 has a plurality of friction plates 23 a and is disposed between the clutch holding portion 19 a of the sun gear 19 and the clutch holding member 25 of the carrier 22. In addition, a disc spring 39 is disposed between the clutch holding member 25 and the clutch 23 to urge the clutch 23 in the releasing direction.

  The clutch holding member 25 is diffusion bonded to the open end 22c of the columnar portion 22b of the carrier 22 by sintering. Specifically, the clutch holding member 25 is bonded through the following steps.

  On the inner peripheral surface of the plate portion 25a of the clutch holding member 25, a fitting concave portion 25e into which the open side end portion 22c is fitted is formed. Similarly, the open end 22c of the green compact carrier 22 is fitted into the fitting recess 25e of the green compact clutch holding member 25 and positioned by a jig. By sintering in this state, the open end 22c and the fitting recess 25e are diffusion bonded. Thereby, the joint surface 38 joined integrally is formed.

The open end surface 22d of each columnar portion 22b protrudes toward the clutch by t from the portion (joint bottom surface) 38a of the bottom surface of the clutch holding member 25 where the columnar portion 22b is joined . The piston load P acting via the clutch 23 is supported by the open end face 22d of each columnar portion 22b protruding by t.

  Further, the disc spring 39 is disposed so that an inner peripheral portion thereof is in contact with the open-side end surface 22 d and an outer peripheral portion is inclined inward so as to be separated from the joint bottom surface 38 a of the clutch holding member 25. As a result, the piston load P acts only on the open side end face 22d via the disc spring 39.

  When a shift lever (not shown) is operated to the neutral position, the hydraulic pressure in the hydraulic chambers 32 and 35 is released, and the return spring 37 retracts the pistons 31 and 34 in the release direction. As a result, the rotational force transmitted to the input shaft 4 via the crankshaft 3 is transmitted to the sun gear 19, but the carrier 22 rotates idly, and the rotational force is not transmitted to the ring gear and the primary shaft 13.

  When the shift lever is operated to the drive position (forward movement side), the hydraulic pressure is supplied to the hydraulic chamber 35 on the brake side, and the brake piston 34 moves forward to engage the brake 24. As a result, the carrier 22 is fixed to the inner case 30 in a non-rotatable manner, and the rotation of the sun gear 19 is transmitted to the ring gear 20 and the primary shaft 13 via the pinion gear 21, so that the wheels rotate in the forward direction.

  When the shift lever is operated to the reverse position (reverse drive side), the hydraulic pressure in the hydraulic chamber 35 on the brake side is released, the brake piston 34 moves backward, and the hydraulic pressure is supplied to the hydraulic chamber 32 on the clutch side. Advances and connects the clutch 23. Thus, the carrier 22 is fixed to the sun gear 19 so as to rotate together, and the ring gear 20 rotates in the same direction together with the sun gear 19, so that the wheel rotates in the reverse direction.

  According to the present embodiment, since the open side end surface 22d of each columnar portion 22b formed integrally with the carrier body 22a protrudes from the joint bottom surface 38a of the clutch holding member 25 toward the clutch side, the piston load P Without being transmitted to the member 25, it is transmitted from the respective columnar portions 22b to the casing 2 via the carrier body 22a. As a result, the reaction force of the piston load P does not act on the joint surface 38 between the columnar portion 22b and the clutch holding member 25, so that the concern about the strength of the joint surface 38 can be eliminated. Can be increased.

  Further, since the open side end face 22d of each columnar part 22b is merely protruded to the clutch side from the joint bottom face 38a of the clutch holding member 25, the number of parts and the number of assembling steps are increased as in the case where a separate support member is provided. Such a problem does not occur.

  In the above embodiment, the case where each columnar portion 22b of the carrier 22 and the clutch holding member 25 are diffusion-bonded by sintering has been described as an example. However, in the present invention, the carrier and the clutch holding member are forged or cast. It is possible to make them both and to join them together by welding, and in this case as well, substantially the same effect as the above embodiment can be obtained.

  In the above-described embodiment, the V-belt type continuously variable transmission mechanism is provided with the planetary gear mechanism in the forward / reverse switching device, and the sun gear input is the ring gear output. The present invention can also be applied to a case where it is selected as appropriate. Furthermore, the present invention can be applied to a planetary gear mechanism of a multi-plate clutch type automatic transmission.

It is a block diagram of the automatic transmission by one Embodiment of this invention. It is sectional drawing of the planetary gear mechanism of the said automatic transmission. It is principal part sectional drawing of the carrier of the said planetary gear mechanism. It is a figure for demonstrating the formation process of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic transmission 19 Sun gear 20 Ring gear 21 Pinion gear 22 Carrier 22a Carrier main body 22b Column-shaped part 22c Open side end part 22d Open side end face 23 Clutch 25 Clutch holding member 38a Joint part bottom face P Piston load

Claims (1)

A sun gear, a ring gear arranged so as to surround the sun gear, a pinion gear arranged between the ring gear and the sun gear, a carrier supporting the pinion gear, and a carrier arranged between the carrier and the sun gear. In an automatic transmission with a planetary gear mechanism including a clutch,
A carrier body that pivotally supports the pinion gear, a columnar part that is integrally formed with the carrier body and extends toward the clutch, and a clutch holding member that is joined to the open end of the columnar part and holds the clutch And
The open side end surface of the columnar part is protruded to the clutch side from the part of the bottom surface of the clutch holding member where the columnar part is joined ,
A disc spring that urges the clutch in the release direction between the clutch holding member and the clutch, an inner peripheral portion of which is in contact with the open side end surface, and an outer peripheral portion of the bottom surface of the clutch holding member, The columnar part is arranged so as to be inclined so as to be separated from the joined part,
An automatic transmission characterized in that a piston load acting via the clutch is supported only by an open end surface of the columnar part with the disc spring interposed therebetween .

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