JP2016191412A - Brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake device capable of reducing dragging loss by reducing an amount of lubricant flowing between friction plates.SOLUTION: A second brake B-2 includes friction plates 31, a piston member 33 pressing the friction plate 31 by a hydraulic pressure supplied to a hydraulic oil chamber 36, and a return spring 35 energizing the piston member 33 through an outer friction plate 31A positioned at a piston member 33 side, of the friction plates 31. The piston member 33 has an oil hole 33c penetrating downward, and an inner peripheral face 33bs of a diameter larger than an inner peripheral-side end portion 31Aa of the outer friction plate 31A, on an extended portion 33b extended to be kept into contact with the outer friction plate 31A.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a brake device used in an automatic transmission mounted on a vehicle.

  For example, an automatic transmission mounted on a vehicle such as an automobile uses a multi-plate brake device that locks the rotation of a gear with respect to a case in order to change a transmission path. Generally, the brake device engages the friction plate by pressing the friction plate with the piston member based on the supplied hydraulic pressure, and releases the friction plate by pushing the piston member back with a return spring when the hydraulic pressure is discharged. Is configured to do. And in such a brake device, what has improved the freedom degree of arrangement | positioning of a brake device is proposed by arrange | positioning a return spring in the spline groove | channel of the case in the outer peripheral side of a friction board (patent document) 1).

JP 2014-105852 A

  By the way, when assembling the brake device, for example, if a plurality of return springs arranged in the circumferential direction are assembled while being aligned with each other, there is a problem that it takes time for assembly. For this reason, in Patent Document 1, one end of each return spring is fixed to the retainer plate, and a plurality of return springs are assembled to the case together with the retainer plate.

  The thing of the said patent document 1 is comprised so that a retainer plate may contact | abut with a piston member, However, With this structure, when releasing a brake device, the friction board adjacent to a retainer plate is pressed with a return spring. Therefore, there is a problem that the interval between the plurality of friction plates tends to be narrowed. If the gap between the friction plates is narrow at the time of release, the shearing resistance of the lubricating oil increases, drag loss increases, and hinders improvement in vehicle fuel efficiency.

  Therefore, the retainer plate is arranged on the opposite side of the piston member through the friction plate in the axial direction, and the friction plate at the end on the piston member side is pressed by the return spring, and the end of the retainer plate is moved along with the movement of the piston member at the time of release. It is conceivable that the distance between the friction plates at the time of release is increased as much as possible by moving the friction plates.

  However, even in such a configuration, the friction plate at the end on the piston member side is pressed by the return spring and moves integrally with the piston member, so that the lubrication guided to the inside of the piston member is performed. Oil does not escape from between the piston member and the friction plate pressed against it, but flows between the friction plate at the end of the piston member and the adjacent friction plate. There is a problem in that dragging loss increases.

  Therefore, an object of the present invention is to provide a brake device that can reduce the amount of lubricating oil flowing between friction plates and reduce drag loss.

A brake device according to the present invention includes a plurality of outer friction plates that are spline-engaged with a plurality of grooves formed in a case, and the plurality of outer friction plates and a plurality of inner friction plates that are alternately arranged in the axial direction. A friction plate having
A piston member that forms a hydraulic oil chamber with a cylinder portion and is disposed on one side of the friction plate in the axial direction, and presses the friction plate with hydraulic pressure supplied to the hydraulic oil chamber;
One side end outer friction plate disposed on the outer peripheral side of the plurality of outer friction plates and disposed in the plurality of grooves, and disposed on one end in the axial direction of the plurality of outer friction plates. A return spring that urges the piston member toward the cylinder part via,
The piston member is
A pressure receiving portion forming the hydraulic oil chamber;
An extension that extends in the axial direction from the pressure receiving portion and contacts the outer friction plate at the one end.
An oil hole penetrating downward in the extension portion, and
The extension portion has an inner peripheral surface having a diameter larger than that of an inner peripheral side end portion of the one side end outer friction plate at an end portion on the other side in the axial direction.

  According to the present invention, the lubricating oil that has flowed from the inner peripheral side to the portion having the inner peripheral surface having a larger diameter than the inner peripheral side end of the one side end outer friction plate in the extension portion of the piston member. After a large amount of oil is collected, it is discharged from the oil hole, so that the amount of lubricating oil flowing to the friction plate can be reduced, drag loss on the friction plate can be reduced, and the fuel consumption of the vehicle equipped with this brake device can be reduced. Improvements can be made.

The skeleton figure which shows typically the automatic transmission which has this brake device. The engagement table of this automatic transmission. Sectional drawing which shows a part of automatic transmission containing this brake device.

  Hereinafter, the present embodiment will be described with reference to FIGS. The automatic transmission 1 equipped with the brake B-2 according to the present embodiment is an automatic transmission suitable for being mounted on a vehicle such as an FF (front engine / front drive) type, for example, in FIG. The left-right direction corresponds to the left-right direction in the actual vehicle mounting state (or the left-right reverse direction). For convenience of explanation, the right side in the figure, which is the drive source side of the engine or the like, is referred to as “front side” (the other side in the axial direction). ), The left side in the figure is called “rear side” (one side in the axial direction).

  First, a schematic configuration of the automatic transmission 1 will be described with reference to FIG. As shown in FIG. 1, an automatic transmission 1 suitable for use in, for example, an FF type vehicle has a torque converter 2 having a lock-up clutch 2a on the front side, and a transmission mechanism 3 on the rear side. A counter shaft portion 4 and a differential portion 5 are arranged.

  The torque converter 2 is disposed on an axis centering on the input shaft 7A of the transmission mechanism 3 that is coaxial with the output shaft 10 of an engine (not shown), for example, and the transmission mechanism 3 is connected to the input shaft 7A. Are arranged on an axis centering on an intermediate shaft 7B connected on the same axis. Further, the counter shaft portion 4 is disposed on a counter shaft 12 that is parallel to the input shaft 7A and the intermediate shaft 7B, and the differential portion 5 is driven left and right on an axis parallel to the counter shaft 12. The shafts 15 and 15 are arranged.

  The skeleton diagram shown in FIG. 1 shows the automatic transmission 1 in a plan view, and the input shaft 7A, the intermediate shaft 7B, the counter shaft 12, and the left and right drive shafts 15, 15 are shown. Is a triangular positional relationship in a side view.

  The transmission mechanism 3 is provided with an input shaft 7A to which rotation from the engine is transmitted via the torque converter 2, and an intermediate shaft 7B connected to the rear side of the input shaft 7A. Yes. That is, in the automatic transmission 1, the input shaft 7 in a broad sense is configured by the input shaft 7A and the intermediate shaft 7B. The transmission mechanism 3 includes a planetary gear DP on the input shaft 7A, and a planetary gear unit PU on the intermediate shaft 7B.

  The planetary gear DP includes a first sun gear S1, a first carrier CR1, and a first ring gear R1, and the first carrier CR1 has a pinion P2 and a first pinion meshing with the first sun gear S1. This is a so-called double pinion planetary gear having pinions P1 meshing with the ring gear R1 so as to mesh with each other.

  On the other hand, the planetary gear unit PU has a second sun gear S2, a third sun gear S3, a second carrier CR2, and a second ring gear R2 as four rotating elements, and the second carrier CR2 3 is a so-called Ravigneaux type planetary gear having a long pinion P3 meshing with the third sun gear S3 and the second ring gear R2 and a short pinion P4 meshing with the second sun gear S2.

  The rotation of the first sun gear S1 of the planetary gear DP is fixed with respect to the case 6. The first carrier CR1 is connected to the input shaft 7A so as to be the same rotation as the input shaft 7A (hereinafter referred to as “input rotation”), and the fourth clutch C−. 4 is connected. Further, the first ring gear R1 is decelerated by the input rotation being decelerated by the fixed first sun gear S1 and the input first carrier CR1, and the first clutch C-1 And the third clutch C-3.

  The third sun gear S3 of the planetary gear unit PU is connected to the first brake B-1 and can be fixed to the case 6, and the fourth clutch C-4 and the third clutch. Connected to C-3, the input rotation of the first carrier CR1 via the fourth clutch C-4, the reduced rotation of the first ring gear R1 via the third clutch C-3, Each can be entered freely. Further, the second sun gear S2 is connected to the first clutch C-1, and the reduced rotation of the first ring gear R1 can be input.

  Further, the second carrier CR2 is connected to the second clutch C-2 (clutch device) to which the rotation of the input shaft 7A is input via the intermediate shaft 7B, and the second clutch C-2 is connected to the second clutch C-2. The input rotation is freely input via the one-way clutch F-1 and the second brake B-2 (brake device) and is connected to the case 6 via the one-way clutch F-1. The rotation in one direction is restricted, and the rotation can be fixed (locked) via the second brake B-2. The second ring gear R2 is connected to a counter gear 8 that is rotatably supported with respect to a center support member 19 fixed to a mission case 6B described later in detail.

  The counter gear 8 is engaged with a counter driven gear 11 fixed on the counter shaft 12 of the counter shaft portion 4, and the output gear formed on the outer peripheral surface of the counter shaft 12. The gear 14 of the differential part 5 is meshed via 12a. The gear 14 is fixed to the differential gear 13 and is connected to the left and right drive shafts 15 and 15 via the differential gear 13.

  The automatic transmission 1 configured as described above includes the first to fourth clutches C-1 to C-4, the first and second brakes B-1 and B-2, and the one-way shown in the skeleton of FIG. When the clutch F-1 is engaged and disengaged in the combinations shown in the engagement table of FIG. 2, the first forward speed (1st) to the eighth forward speed (8th), and the first reverse speed (Rev1) to reverse 2 High speed (Rev2) is achieved.

  Next, the detailed structure of the second brake B-2 and its periphery in the automatic transmission 1 will be described with reference to FIG. As described above, the planetary gear unit PU is disposed on the outer peripheral side of the intermediate shaft 7B (see FIG. 1), and the planetary gear unit PU is provided with the second carrier CR2. The second carrier CR2 is capable of rotating a plurality of long pinions P3 and a plurality of short pinions P4 (see FIG. 1) by a first side plate 51, a second side plate 52, and a bridge (not shown) connecting them. A frame (structure) that supports the long pinion shaft 53 and the short pinion shaft (not shown) to be supported is configured.

  An inner friction plate 21b of a second clutch C-2, which will be described later, is spline-engaged with the bridge constituting the frame of the second carrier CR2. Further, the inner race 71 of the one-way clutch F-1 is fixed to the bridge by, for example, welding. The one-way clutch F-1 includes the inner race 71, the outer race 72, and a one-way restriction mechanism (for example, a roller cam mechanism or a sprag mechanism) that are interposed between the inner race 71 and the inner race 71 to restrict the rotation direction of the inner race 71 in one direction. Etc.) 73. A second ring gear R2 meshing with the long pinion P3 is disposed on the inner peripheral side of the inner race 71 of the one-way clutch F-1, and the second ring gear R2 is connected to the counter gear 8. ing.

  On the other hand, the second clutch C-2 is arranged from the rear side of the planetary gear unit PU to the outer peripheral side of the rear portion. The second clutch C-2 has a friction plate 21 having a plurality of outer friction plates 21a and a plurality of inner friction plates 21b, and a hydraulic servo 20 that presses and drives the friction plates 21 to be engageable. Configured.

  The hydraulic servo 20 has a clutch drum 22, a piston member 23, a cancel plate 24, and a return spring 25, and these constitute a hydraulic oil chamber 26 and a cancel oil chamber 27. The clutch drum 22 is integrally formed by welding, for example, an inner peripheral member 22A and an outer peripheral member 22B. Of these, the outer peripheral side member 22B extends from the inner peripheral side member 22A to the friction plate 21, and extends in a drum shape in the axial direction from the distal end side of the extended portion 22Ba. The outer friction plate 21a has a drum portion 22Bb formed with a spline portion 22Bs for spline engagement. A snap ring 29 is fitted to the tip of the spline portion 22Bs, and the forward movement of the friction plate 21 is restricted. The front end portion 22Bc of the drum portion 22Bb, that is, the end portion on the front side of the clutch drum 22 is arranged to extend to the front side from the rear end portion 38a of the hub member 38 described later.

  On the front side of the inner peripheral member 22A, a portion facing the piston member 23 is formed as a cylinder for configuring the hydraulic oil chamber 26, and the inner peripheral member 22A and the outer peripheral member 22B include The piston member 23 is fitted so as to be slidable in the axial direction. As a result, the piston member 23 forms a hydraulic oil chamber 26 with the clutch drum 22, and is configured to be able to press the friction plate 21 in accordance with the hydraulic pressure supplied to the hydraulic oil chamber 26. . A cancel plate 24 is positioned and disposed on the clutch drum 22, a return spring 25 is contracted between the cancel plate 24 and the piston member 23, and the hydraulic oil chamber 26 is centrifuged. A cancel oil chamber 27 for canceling the hydraulic pressure is configured.

  Next, the second brake (brake device) B-2 that is a main part of the present embodiment will be described in detail. The second brake B-2 includes a friction plate 31 having a plurality of outer friction plates 31a and a plurality of inner friction plates 31b arranged alternately in the axial direction, and a hydraulic servo 30 for locking the friction plates 31. It has. The inner friction plate 31b is spline-engaged with the hub member 38 described above and is drivingly connected to the second carrier CR2 via the inner race 71. Further, the outer friction plate 31 a is spline-engaged with a spline portion 6 s formed on the inner peripheral surface of the case 6. That is, a plurality of grooves 6 d constituting the spline portion 6 s are formed on the inner peripheral surface of the case 6. The plurality of outer friction plates 31a include an outer friction plate (one side end outer friction plate) 31A disposed at the end on the rearmost side and an outer friction plate (the other end disposed on the front end). Side end outer friction plate) 31B and a normal outer friction plate 31a disposed between them.

  The hydraulic servo 30 includes a cylinder portion 32 formed on the inner surface of the case 6, a piston member (piston member) 33, a plurality of return springs 35 that urge the piston member 33 toward the cylinder portion 32, and a retainer plate 37. The hydraulic oil chamber 36 is constituted by the cylinder portion 32 and the piston member 33. Each of the plurality of return springs 35 is disposed in the groove 6d of the spline portion 6s, and a front end portion 35a of each return spring 35 is engaged with the retainer plate 37, and the rear end on the opposite side. The portion 35b is disposed so as to be in pressure contact with the outer friction plate 31A disposed at the foremost end of the plurality of outer friction plates 31a. That is, the outer friction plate 31A is different from the other outer friction plates 31a in that a claw portion that is formed on the outer peripheral side and enters the groove 6d is formed longer on the outer peripheral side, and is in contact with the end portion 35b of the return spring 35. Has been.

  When assembling the second brake B-2, the piston member 33, the plurality of outer friction plates 31a (including the outer friction plate 31A and the outer friction plate 31B), and the plurality of inner friction plates 31b are assembled to the case. On the other hand, a plurality of return springs 35 are assembled to the retainer plate 37, and a set of the return spring 35 and the retainer plate 37 is assembled to the case 6. Therefore, the retainer plate 37 is disposed on the front side of the outer friction plate 31B. Thereafter, the spacer 39, the outer race 72 and the like are assembled to the case 6 and positioned and fixed by the snap ring 74, whereby the retainer plate 37 is also positioned and fixed.

  On the other hand, the piston member 33 is disposed opposite to the cylinder portion 32 to form a hydraulic oil chamber 36, and extends from the pressure receiving portion 33a to the friction plate 31, more specifically, until it contacts the outer friction plate 31A. An extension portion 33b, and the tip of the extension portion 33b constitutes a contact portion 33ba that comes into contact with the outer friction plate 31A. The extension 33b is formed with an oil hole 33c penetrating downward from the inner circumference side to the outer circumference side on the lower side in the circumferential direction, and further from the oil hole 33c in the extension part 33b. Also on the front side, there is an inner peripheral surface 33bs having a larger diameter than the inner peripheral end portion 31Aa which is the inner diameter of the outer friction plate 31A. Of the opening 33d that opens above the oil hole 33c, the lowermost lower end 33da is connected to the inner peripheral surface 33bs, that is, the lower end 33da is the inner peripheral side that is the inner diameter of the outer friction plate 31A. It is located below the end 31Aa.

  The second brake B-2 configured as described above resists the urging force of the return spring 35 when the hydraulic pressure is supplied to the hydraulic oil chamber 36 from an oil passage in the case 6 (not shown). The piston member 33 and the outer friction plate 31A are pressed and driven forward, the friction plate 31 is locked to the case 6, and the second brake B-2 is engaged (locked). In the engaged state of the friction plate 31, the friction plate 31 fixes the second carrier CR <b> 2 to the case 6 in a non-rotatable manner via the hub member 38 and the inner race 71. At this time, since the piston member 33 presses the outer friction plate 31A, the piston member 33 and the outer friction plate 31A are not separated and remain in close contact with each other.

  On the other hand, when the hydraulic pressure is discharged from the hydraulic oil chamber 36, the outer friction plate 31A and the piston member 33 are moved rearward by the urging force of the return spring 35 to release the friction plate 31, and the second brake B -2 is released. In the released state of the friction plate 31, the power transmission between the hub member 38, the inner race 71, and the second carrier CR2 and the case 6 is disconnected. In this case, the return spring 35 presses the piston member 33 via the outer friction plate 31A, so that the piston member 33 and the outer friction plate 31A are not separated from each other and remain in close contact with each other.

  Further, when the second brake B-2 is in a released state and the outer friction plate 31A and the piston member 33 are most pressed against the cylinder portion 32 by the return spring 35, the second brake B-2 is moved forward of the outer friction plate 31A. The length of the piston member 33 is set so that the adjacent inner friction plate 31b does not fall backward from the hub member 38. In other words, the end portion 38a of the hub member 38 is located on the front side of the outer friction plate 31A. It arrange | positions so that it may be located back rather than side surface 31Ab.

  Next, the path of the lubricating oil flowing from the periphery of the second brake B-2 to the lower side of the second brake B-2 will be described. The flow of the lubricating oil when the second brake B-2 is in the released state as shown in FIG. 3 will be mainly described.

  Lubricating oil is supplied from a hydraulic control device (not shown) to the intermediate shaft 7B (not shown in FIG. 3), and lubrication is performed from the outer periphery of the intermediate shaft 7B toward the planetary gear unit PU and the second clutch C-2. Oil is scattered. The lubricating oil that has lubricated the tooth surfaces of each gear of the planetary gear unit PU flows to the friction plate 21 of the second clutch C-2 as indicated by arrows A1, A2, and A3.

  On the other hand, a part of the lubricating oil flowing into the second clutch C-2 flows into the cancellation oil chamber 27, and the lubricating oil overflowing with the cancellation oil chamber 27 is filled with the second clutch C-2 and the planetary gear. The lubricating oil splashed between the unit PU and the oil flows into the outer peripheral side, passes through the piston member 23 as indicated by an arrow A4, and partially passes through the clutch drum 22 as indicated by an arrow A5. As shown by arrows A6 and A7, the brake B-2 flows to the inner peripheral side of the piston member 33 on the rear side, and the remaining part of the lubricating oil supplied to the friction plate 21 merges with the piston member 33. It flows to the inner peripheral side on the rear side. The lubricating oil that has flown to the inner peripheral side of the rear side of the piston member 33 in this manner is guided below the case 6 through the oil hole 33c formed in the piston member 33 as indicated by an arrow A13. 6 is stored in the oil sump below 6.

  Further, a part of the lubricating oil flowing to the friction plate 21 flows to the outer peripheral side of the clutch drum 22 as indicated by an arrow A8, and the rest flows to the inner peripheral side of the hub member 38 as indicated by an arrow A9. The lubricating oil that has flowed to the inner peripheral side of the hub member 38 flows from the end portion 38a of the hub member 38 to the inner peripheral side end portion 31Aa of the lower (outer peripheral side) outer friction plate 31A, as indicated by an arrow A10. A slight part flows between the outer friction plate 31A and the inner friction plate 31b adjacent thereto as indicated by an arrow A12, but most of them pass over the outer friction plate 31A as indicated by an arrow A11 and move to the piston member. It flows on the inner peripheral surface 33bs of 33. Thus, the lubricating oil flowing from the hub member 38 and the lubricating oil flowing from the friction plate 21 as shown by the arrow A8 (that is, from the inner peripheral side of the second brake B-2 to the front portion of the piston member 33). Lubricating oil) is collected on the inner peripheral surface 33bs of the extension 33b of the piston member 33, and does not get over the outer friction plate 31A, and is open to the lower side of the inner peripheral end 31Aa of the outer friction plate 31A. It flows into the oil hole 33c where the lower end 33da of 33d is located. As described above, since the piston member 33 and the outer friction plate 31A are always in close contact with each other, almost all of the lubricating oil accumulated on the inner peripheral surface 33bs flows into the oil hole 33c. Then, the lubricating oil flowing from the inner peripheral surface 33bs to the oil hole 33c is guided to the lower part of the case 6 through the oil hole 33c and is stored in the oil reservoir below the case 6 as indicated by an arrow A14. Although not shown in FIG. 3, flowing a certain amount of lubricating oil to the friction plate 31 provides better cooling and increases the spacing between the released friction plates. It is preferable to provide a hole.

  Thus, in the case where the second brake B-2 is in the released state, most of the lubricating oil flowing to the inner peripheral side of the hub member 38 is closer to the piston member 33 than the outer friction plate 31A. It is prevented from flowing and overcoming the outer friction plate 31A to the friction plate 31 side. Therefore, a large amount of lubricating oil flows between the outer friction plate 31A and the inner friction plate 31b adjacent to the outer friction plate 31A, and presses the other friction plates 31 except the outer friction plate 31A to increase the drag loss. Can be prevented.

  Note that the flow of the lubricating oil when the second brake B-2 is engaged (locked) is not required to reduce drag loss in the first place, so a detailed description thereof is omitted, but the hydraulic oil chamber Due to the engagement pressure supplied to 36, the outer friction plate 31 </ b> A is moved forward from the end portion 38 a of the hub member 38 by the piston member 33 during engagement, so that the end portion from the inner peripheral side of the hub member 38 is The lubricating oil flowing to the outer peripheral side (downward) through 38a hardly gets over the outer friction plate 31A and goes to the friction plate 31 side.

[Summary of this embodiment]
As described above, the brake device (B-2) according to the present embodiment includes the plurality of external friction plates (31a) that are spline-engaged with the plurality of grooves (6d) formed in the case (6), A friction plate (31) having the plurality of outer friction plates (31a) and a plurality of inner friction plates (31b) arranged alternately in the axial direction;
A hydraulic oil chamber (36) is formed between the cylinder portion (32) and the friction plate (31) is disposed on one side in the axial direction, and is supplied by the hydraulic pressure supplied to the hydraulic oil chamber (36). A piston member (33) for pressing the friction plate (31);
Located on the outer peripheral side of the plurality of outer friction plates (31a) and disposed in the plurality of grooves (6d), and disposed at one end portion in the axial direction of the plurality of outer friction plates (31a). A return spring (35) for urging the piston member (33) toward the cylinder part (32) through an outer friction plate (31A) on one side.
The piston member (33)
A pressure receiving portion (33a) forming the hydraulic oil chamber (36);
An extension portion (33b) extending in the axial direction from the pressure receiving portion (33a) and contacting the one side end outer friction plate (31A);
An oil hole (33c) that penetrates downward in the extension (33b),
The extension portion (33b) has an inner peripheral surface (33bs) having a diameter larger than that of the inner peripheral side end portion (31Aa) of the one side end outer friction plate (31A) at the other end portion in the axial direction. Have

  As a result, in the extension portion 33b of the piston member 33, the inner peripheral surface 33bs having a larger diameter than the inner peripheral side end portion 31Aa of the outer friction plate 31A at the end portion on the piston member 33 side is Since most of the lubricating oil flowing from the side is collected and discharged from the oil hole 33c, the lubricating oil flowing in the friction plate 31 (especially between the outer friction plate 31A and the adjacent inner friction plate 31b) flows. (Lubricating oil) can be reduced, drag loss in the friction plate 31 can be reduced, and fuel efficiency of a vehicle equipped with the second brake B-2 can be improved.

  Further, in the brake device (B-2) according to the present embodiment, the oil hole (33c) has a lower end in the opening (33d) that opens to the inner peripheral side, and the one side end outer friction plate (31A). ) Is located below the inner peripheral side end (31Aa).

  As a result, the lubricating oil collected on the inner peripheral surface 33bs of the extension 33b of the piston member 33 flows into the opening 33d of the oil hole 33c before passing over the inner peripheral end 31Aa of the outer friction plate 31A. It is possible to prevent a large amount of lubricating oil from flowing into the friction plate 31 from flowing into the friction plate 31, reduce drag loss in the friction plate 31, and reduce the drag loss of the vehicle equipped with the second brake B-2. Fuel consumption can be improved.

The brake device (B-2) according to the present embodiment includes a hub member (38) that is spline-engaged with the plurality of inner friction plates (31b).
One end (38a) in the axial direction of the hub member (38) is connected to the piston member (33) by the return spring (35) via the one side end outer friction plate (31A). In a state of being pressed against the cylinder part (32), the one side end outer friction plate (31A) is positioned on one side in the axial direction with respect to the other side surface (31Ab) in the axial direction.

  As a result, during the release of the second brake B-2, much of the lubricating oil that has flowed to the inner peripheral side of the hub member 38 flows to the piston member 33 side of the outer friction plate 31A, and a large amount flows to the friction plate 31. The lubricating oil can be prevented from flowing, the drag loss in the friction plate 31 can be reduced, and the fuel efficiency of the vehicle equipped with the second brake B-2 can be improved.

  Furthermore, in the brake device (B-2) according to the present embodiment, the hub member (38) has a clutch drum (22) that extends to the other side from the one end (38a) in the axial direction. It arrange | positions at the outer peripheral side of a clutch apparatus (C-2).

  Thereby, the lubricating oil flows from the clutch drum 22 of the second clutch C-2 to the inner peripheral side of the hub member 38, but most of the lubricating oil flowing to the inner peripheral side of the hub member 38 is the outer friction plate. It is possible to prevent a large amount of lubricating oil from flowing through the friction plate 31 by flowing toward the piston member 33 side of 31A.

  The brake device (B-2) according to the present embodiment is engaged with the other end (35a) in the axial direction of the return spring (35), and the plurality of outer friction plates (31a). The other side end friction plate (31B) disposed at the other end portion in the axial direction of the other end portion is disposed on the other side in the axial direction, and the other side in the axial direction by the case (6). A retainer plate (37) that is restricted from moving to the right is provided.

  Thereby, it is possible to reduce the time when the return spring 35 is assembled to the automatic transmission 1, but it is possible to easily widen the gap between the friction plates 31 when the second brake B-2 is released. it can.

<Possibility of other embodiments>
In the present embodiment described above, the automatic transmission 1 has been described as an example that achieves, for example, the eighth forward speed and the second reverse speed. However, the present invention is not limited to this, and for example, the sixth forward speed and the reverse speed. Any automatic transmission may be used as long as the structure is equipped with a brake device.

  In the above-described embodiment, the automatic transmission 1 is connected to the engine only. However, for example, an automatic transmission for a hybrid vehicle equipped with a motor / generator instead of the torque converter 2 is used. There may be.

6 ... Case 6d ... Groove 22 ... Clutch drum 31a ... Outer friction plate 31b ... Inner friction plate 31 ... Friction plate 31A ... One side end outer friction plate (outermost friction plate)
31Aa ... inner peripheral side end 31Ab ... side 31B ... other side end friction plate (outermost friction plate)
32 ... Cylinder part 33 ... Piston member 33a ... Pressure receiving part 33b ... Extension part 33bs ... Inner peripheral surface 33c ... Oil hole 33d ... Opening part 35 ... Return spring 35a ... End part 36 ... Hydraulic oil chamber 37 ... Retainer plate 38 ... Hub member 38a ... end B-2 ... brake device (second brake)
C-2 ... Clutch device (second clutch)

Claims (5)

A friction plate having a plurality of outer friction plates that are spline-engaged with a plurality of grooves formed in the case, and a plurality of outer friction plates and a plurality of inner friction plates that are alternately arranged in the axial direction;
A piston member that forms a hydraulic oil chamber with a cylinder portion and is disposed on one side of the friction plate in the axial direction, and presses the friction plate with hydraulic pressure supplied to the hydraulic oil chamber;
One side end outer friction plate disposed on the outer peripheral side of the plurality of outer friction plates and disposed in the plurality of grooves, and disposed on one end in the axial direction of the plurality of outer friction plates. A return spring that urges the piston member toward the cylinder part via,
The piston member is
A pressure receiving portion forming the hydraulic oil chamber;
An extension that extends in the axial direction from the pressure receiving portion and contacts the outer friction plate at the one end.
An oil hole penetrating downward in the extension portion, and
The extension portion has an inner peripheral surface having a diameter larger than an inner peripheral side end portion of the one side end outer friction plate at an end portion on the other side in the axial direction.
Brake device. The lower end of the opening that opens to the inner peripheral side of the oil hole is located below the inner peripheral end of the one-side end outer friction plate,
The brake device according to claim 1. A hub member that is spline-engaged with the plurality of inner friction plates;
One end of the hub member in the axial direction is outside the one end in a state where the piston member is pressed against the cylinder by the return spring via the outer friction plate at the one end. It is located on one side of the axial direction from the other side surface of the friction plate in the axial direction.
The brake device according to claim 1 or 2. The hub member is disposed on an outer peripheral side of a clutch device having a clutch drum extending to the other side from an end portion on one side in the axial direction.
The brake device according to claim 3. The return spring is engaged with the other end portion in the axial direction, and the shaft is more than the other end end friction plate disposed at the other end portion in the axial direction among the plurality of outer friction plates. A retainer plate that is disposed on the other side of the direction and whose movement is restricted to the other side in the axial direction by the case;
The brake device according to any one of claims 1 to 4.

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