JP2007170442A - Automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic transmission capable of improving assemblability by reducing the number of components and simplifying a structure, and of increasing stiffness of a transmission case by reducing the diameter of an opening part of a main body case in a brake mechanism provided near an opening part of the main body case of a transmission case. <P>SOLUTION: The transmission case 1 includes the body case 20 having the opening part 21 formed on an end part in an opposite side of an engine, and a case cover 25 blocking the opening part 21 of the body case 20. A brake mechanism 30 is provided near the opening part 21 of the body case 20 and an outer circumference part of a spring retainer 34 of the brake mechanism 30 is locked on an opening part side end part of the body case 20. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an automatic transmission, and more particularly to a structure of a brake mechanism.

  2. Description of the Related Art Conventionally, an automatic transmission mounted on an automobile or the like includes an input shaft to which engine output is input, an output member that outputs driving force to a wheel side, and a shift that is interposed between the input shaft and the output member. A mechanism and a transmission case for housing the transmission mechanism. The transmission mechanism includes a plurality of brake mechanisms, clutch mechanisms, gear mechanisms, and the like. The transmission case includes a main body case having an opening formed at an end opposite to the engine, and an opening of the main body case. A case cover having a case cover for closing the part and having a brake mechanism disposed in the vicinity of the opening of the main body case has been put to practical use (see, for example, Patent Document 1).

  In the brake mechanism of Patent Document 1, a brake piston is attached to a case cover, and a plurality of return springs for urging the brake piston toward the brake release side (toward the case cover) are provided. A spring retainer that supports the end is provided. The case cover has a cylindrical portion fitted into the main body case, and a spring retainer is fitted into the cylindrical portion. A ring groove is formed on the inner surface of the cylindrical portion, and a snap ring is fitted in the ring groove. The outer periphery of the spring retainer biased toward the multi-plate brake by the return spring is locked to the snap ring. The

JP 2003-278797 A

  In a brake mechanism such as that disclosed in Patent Document 1, a snap ring for locking the spring retainer is provided, and in order to attach this snap ring, a cylindrical portion fitted inside the main body case is formed on the case cover. Since it is necessary to form a ring groove in the cylindrical portion, the number of parts is large, the structure is complicated, and the assembly load is increased. In addition, the cylindrical portion of the case cover is fitted into the main body case and the ring groove is formed in the cylindrical portion, so that the diameter of the opening is increased and the rigidity of the transmission case is reduced.

  An object of the present invention is to reduce the number of parts in the brake mechanism disposed near the opening of the main body case of the transmission case, simplify the structure, improve the assembly, and reduce the opening of the main body case to a small diameter. It is to provide an automatic transmission that can improve the rigidity of the transmission case.

  An automatic transmission according to a first aspect of the present invention includes an input shaft to which engine output is input, an output member that outputs driving force to the wheels, a speed change mechanism that is interposed between the input shaft and the output member, An automatic transmission including a transmission case that houses a transmission mechanism, wherein the transmission case includes a main body case having an opening formed at an end opposite to the engine, and the opening of the main body case is closed. And the transmission mechanism includes a brake mechanism disposed in the vicinity of the opening of the main body case. The brake mechanism is mounted on the case cover and the multi-plate brake. A brake piston that presses the brake piston toward the fastening side, a plurality of return springs that bias the brake piston toward the brake release side, and a spline that supports the multi-plate brake side ends of these return springs A Nguritena, the outer peripheral portion of the spring retainer, characterized in that locked to the opening side end portion of the main body case.

  In the brake mechanism, when the brake piston is driven and the multi-plate brake is pressed toward the fastening side, the multi-plate brake is fastened and the brake piston is stopped, the brake piston is returned by a plurality of return springs. The multi-plate brake is released. The spring retainer supports the multi-plate brake side ends of the plurality of return springs, but the outer periphery of the spring retainer biased by the plurality of return springs is locked to the opening side end of the main body case. In other words, the spring retainers reliably support the multi-plate brake side ends of the plurality of return springs, and the return pistons reliably bias the brake piston toward the brake release side.

  Thus, it is possible to omit the snap ring and the ring groove for mounting the snap ring, which are conventionally required for locking the spring retainer. In addition, you may provide the structure which controls the movement of the axial direction (movement direction of a brake piston) and / or the circumferential direction of the outer peripheral part of a spring retainer.

The following configuration can be adopted for the invention of claim 1.
The spring retainer includes one or a plurality of locking flange portions that are disposed between the opening side end portion of the main body case and the outer peripheral side portion of the case cover and locked to the opening side end portion of the main body case. (Claim 2). The brake piston has a piston portion, and a plurality of cross-section arc-shaped brake pressing portions provided on the piston portion at appropriate circumferential intervals and extending toward the multi-plate brake, and the plurality of return springs are It arrange | positions in the position shifted to the circumferential direction with respect to the several brake press part.

  The spring retainer has an annular plate portion with which the multiple plate brake side ends of the plurality of return springs abut, and the annular plate portion is disposed between the piston portion and the multiple plate brake. . A plurality of arc-shaped slits through which the plurality of brake pressing portions are inserted are formed in the annular plate portion (Claim 5).

  The multiple plate brake side ends of the plurality of return springs are fixed to the spring retainer. The case cover is provided with an annular piston cylinder portion projecting into the main body case, and the spring retainer is temporarily attached to the outer peripheral surface of the outer peripheral wall of the piston cylinder portion when the automatic transmission is assembled. An extending portion is provided, and the one or more locking flange portions are provided so as to extend outward from the extending portion.

  According to the automatic transmission of claim 1, the transmission case has a main body case in which an opening is formed at an end opposite to the engine, and a case cover that closes the opening of the main body case, Since the brake mechanism is disposed in the vicinity of the opening of the main body case and the outer periphery of the spring retainer of the brake mechanism is locked to the opening side end of the main body case, the spring retainer can The end of the multi-plate brake can be supported securely, and the snap ring, which was conventionally required to lock the spring retainer, can be omitted, and the ring groove for mounting the snap ring can be omitted. As a result, the number of parts can be reduced, the structure can be simplified, the assembly load can be reduced, and the opening of the main body case can be reduced in diameter to improve the rigidity of the transmission case. It becomes possible.

  According to the automatic transmission of the second aspect, the spring retainer is disposed between the opening side end portion of the main body case and the outer peripheral side portion of the case cover and is locked to the opening side end portion of the main body case. Or since it has a plurality of locking flanges, one or more locking flanges on the outer periphery of the spring retainer can be securely locked to the opening side end of the main body case, and the axial direction of the spring retainer It is possible to prevent the rattling from occurring by regulating the movement in the (movement direction of the brake piston).

  According to the automatic transmission of the third aspect, the brake piston includes a piston portion and a plurality of brake pressing portions having an arcuate cross section provided on the piston portion at appropriate circumferential intervals and extending toward the multi-plate brake. Since the plurality of return springs are arranged at positions shifted in the circumferential direction with respect to the plurality of brake pressing portions, the plurality of brake pressing portions can uniformly press the multi-plate brake, and the plurality of returns The spring can uniformly bias the brake piston, and the plurality of brake pressing portions and the return spring can be arranged in the radial direction in a compact manner, and the automatic transmission can be downsized in the radial direction.

  According to the automatic transmission of the fourth aspect, the spring retainer has the annular plate portion with which the multiple plate brake side end portions of the plurality of return springs abut, and the annular plate portion is disposed between the piston portion and the multiple plate brake. Thus, the annular plate portion can reliably support the multi-plate brake side end portions of the plurality of return springs.

  According to the automatic transmission of claim 5, since the plurality of arc-shaped slits through which the plurality of brake pressing portions are inserted are formed in the annular plate portion, the annular plate portion is opposed to the piston portion of the brake piston. The annular plate portion (spring retainer) and the brake piston can be configured compactly.

  According to the automatic transmission of the sixth aspect, since the multi-plate brake side end portions of the plurality of return springs are fixed to the spring retainer, the assemblability of the spring retainer and the plurality of return springs is improved.

  According to the automatic transmission of claim 7, since the case cover is provided with the annular piston cylinder portion protruding into the main body case, the brake piston can be securely attached to the piston cylinder portion, and the spring retainer is The outer surface of the outer peripheral wall of the piston cylinder part has one or more extended parts that can be temporarily fixed when the automatic transmission is assembled, so the case cover and spring retainer can be easily sub-assembled and assembled. Since one or more locking flange portions are provided so as to extend outward from one or more extending portions, the structure of the extending portion and the locking flange portion can be simplified. it can.

  An automatic transmission according to the present invention includes an input shaft to which engine output is input, an output member that outputs driving force to the wheels, a speed change mechanism that is interposed between the input shaft and the output member, and the speed change mechanism. A transmission case that houses the mechanism, and the transmission case has a main body case in which an opening is formed at an end opposite to the engine, and a case cover that closes the opening of the main body case, The speed change mechanism includes a brake mechanism disposed in the vicinity of the opening of the main body case.

  As shown in FIGS. 1 and 3, an automatic transmission 1 mounted on a vehicle such as an automobile includes an input shaft 2 to which engine output is input, and an output corresponding to an output member that outputs driving force to the wheels. A gear 3, a transmission mechanism 4 interposed between the input shaft 2 and the output gear 3, and a transmission case 5 that accommodates the transmission mechanism 4 are provided.

  As shown in FIG. 1, the transmission mechanism 4 includes first to fourth planetary gear mechanisms 10 to 13, LCL 14 (low clutch), HCL 15 (high clutch), 35 RCL 16 (35 reverse clutch), OWCL 17 (one-way clutch), and LRBrk 18. (Low reverse brake), 26Brk19 (26 brake) corresponding to the brake mechanism of the present invention is provided.

  In the first planetary gear mechanism 10, the sun gear 10 a is fixed to the transmission case 5, the pinion carrier 10 c of the pinion 10 b is connected to the clutch drum 14 a on the outer peripheral side of the LCL 14, and the ring gear 10 d is connected to the outer peripheral side of the input shaft 2 and the HCL 15. It is connected to the clutch drum 15a.

  In the second planetary gear mechanism 11, the sun gear 11a is connected to the clutch hub 14b on the inner peripheral side of the LCL 14, the pinion carrier 11c of the pinion 11b is connected to the output gear 3 and the ring gear 12d of the third planetary gear mechanism 12, and the ring gear 11d. Is connected to the drum 18a on the inner peripheral side of the LRBrk 18, and the OWCL 17 is interposed between the drum 18a (ring gear 11d) and the transmission case 5.

  In the third planetary gear mechanism 12, the sun gear 12a is connected to the inner drum 19a of the 26Brk19 and the inner clutch hub 16b of the 35RCL16, and the pinion carrier 12c of the pinion 12b is connected to the drum 18a of the LRBrk18 and the inner circumference of the HCL15. Is connected to the clutch hub 15b.

  In the fourth planetary gear mechanism 13, the sun gear 13 a is fixed to the transmission case 5, the pinion carrier 13 c of the pinion 13 b is connected to the clutch drum 16 a on the outer peripheral side of the 35 RCL 16, and the ring gear 13 d is connected to the input shaft 2.

  LCL14, HCL15, 35RCL16, LRBrk18, and 26Brk19 are controlled by a control device such as an ECU, respectively, so that the gear position of the transmission mechanism 4 is selectively switched to any one of the first to sixth gears and the reverse gear. FIG. 2 shows the states of LCL14, HCL15, 35RCL16, LRBrk18, 26Brk19, and OWCL17 at each gear position, and “◯” indicates the engaged state. Note that the OWCL 17 in the first speed is engaged only when accelerating, and the LRBrk 18 is engaged only when engine braking such as manual mode is required.

  As shown in FIG. 3, the transmission case 5 closes the opening 21 and a main body case 20 having an opening 21 formed at the end (left side in FIG. 3) opposite to the engine (not shown). A case cover 25 is provided, and 26 Brk 19 is disposed in the vicinity of the opening 21. Next, the 26Brk19 (hereinafter referred to as the brake mechanism 30) will be described in detail. The direction of arrow a in FIG. 3 is the axial direction, and the right side of FIG.

  As shown in FIGS. 3 to 6, the brake mechanism 30 includes a multi-plate brake 31, a brake piston 32 that is attached to the case cover 25 and presses the multi-plate brake 31 toward the fastening side (forward), and the brake piston 32. A plurality of (e.g., 16) return springs 33 that bias the brake release side (rearward) and a spring retainer 34 that supports end portions (front end portions) of the return springs 33 on the multi-plate brake side are provided.

  As shown in FIG. 3, the multi-plate brake 31 includes a plurality of (for example, five) friction plates 31 a that are spline-engaged with the rear portion of the main body case 20 and the radial direction of the friction plates 31 a. A plurality of (for example, four) friction disks 31b that are spline-engaged in an outer fitting manner with a drum 30a (19a) disposed inside.

  The plurality of friction plates 31a and the plurality of friction disks 31b are alternately arranged in the axial direction so that the friction plates 31a are located at both front and rear ends. On the front side of the friction plate 31a at the front end, a ring groove 20a is formed in the inner surface of the main body case 20, and the friction plate 31a at the front end is locked from the rear side to a snap ring 31c fitted in the ring groove 20a. .

  Here, the multi-plate clutch 16c of 35RCL16 is disposed radially inward of the multi-plate brake 31 of the brake mechanism 30, and the fourth planetary gear mechanism 13 is disposed radially inward of the multi-plate clutch 16c. The input shaft 2 is rotatably inserted in the sun gear 13 a of the planetary gear mechanism 13. The drum 30a of the brake mechanism 30 has a vertical portion located on the front side of the multi-plate clutch 16c of the 35RCL16 and is connected to the clutch hub 16b of the 35RCL16.

  As shown in FIGS. 3 to 6, the brake piston 32 is disposed on the rear side of the multi-plate brake 31, and is provided to the piston portion 40 and the piston portion 40 at appropriate circumferential intervals (equal intervals). And a plurality of (for example, four) cross-section arc-shaped brake pressing portions 45 extending to the multi-plate brake 31 side (front side). For example, when the number of brake pressing parts 45 is four, each brake pressing part 45 is provided over about 50 degrees with respect to the center of the brake piston 32.

  The piston portion 40 is formed relatively thick in the front-rear direction, and annular grooves 40a and 40b are formed in the outer peripheral portion and the inner peripheral portion of the piston portion 40. The annular seal members 41a and 41b are respectively formed in the annular grooves 40a and 40b. Is installed. The plurality of brake pressing portions 45 are formed integrally with the piston portion 40, extend forward from the outer periphery of the front surface of the piston portion 40, and can come into contact with the friction plate 31 a at the rear end of the multi-plate brake 31. .

  The case cover 25 is provided with an annular piston cylinder portion 26 that protrudes forward into the main body case 20. The piston cylinder part 26 has an outer peripheral wall 26a and an inner peripheral wall 26b integrally formed in the vicinity of the outer periphery of the case cover 25, and the piston part 40 is connected to the piston cylinder part 26 via the annular seal members 41a and 41b. When fitted and mounted and hydraulic pressure is supplied to the piston cylinder portion 26, the brake piston 32 is driven forward.

  As shown in FIGS. 3 to 5, the plurality of return springs 33 are formed of compression coil springs, and are arranged between the piston portion 40 of the brake piston 32 and the annular plate portion 50 of the spring retainer 34. On the other hand, they are arranged symmetrically about the axis at a position shifted in the circumferential direction. For example, when the number of return springs 33 is 16, four return springs 33 are arranged at equal intervals between two brake pressing portions 45 adjacent in the circumferential direction.

  In the piston portion 40 of the brake piston 32, a plurality of pin portions 40 c corresponding to the number of return springs 33 are arranged at positions shifted in the circumferential direction with respect to the plurality of brake pressing portions 45. The rear portions of the plurality of return springs 33 are externally locked on these pin portions 40c.

  As shown in FIGS. 3 to 6, the spring retainer 34 includes an annular plate portion 50, a plurality (for example, four) of extended portions 51, and a plurality of (for example, four) locking flange portions 52.

  The annular plate portion 50 is disposed between the piston portion 40 of the brake piston 32 and the multi-plate brake 31, and the front end portions of the plurality of return springs 33 are in contact with and secured to the annular plate portion 50. For example, the front end portions of the plurality of return springs 33 are caulked and fixed in a state where they pass through the annular plate portion 50. The annular plate portion 50 is formed with a plurality of (for example, four) arcuate slits 40a through which the plurality of brake pressing portions 45 are inserted.

  The plurality of extending portions 51 are arranged at appropriate intervals (equal intervals) in the circumferential direction, are integrally formed with the annular plate portion 50, and are each formed in a circular arc shape extending rearward from the outer peripheral portion of the annular plate portion 50. Has been. The plurality of extending portions 51 are formed to have a larger diameter than the brake piston 32, and are formed on the case cover 25 so as to be positioned on the radially outer side of the brake piston 32 in a state where the brake piston 32 is attached to the case cover 25. The piston cylinder part 26 can be temporarily fixed to the outer peripheral surface of the outer peripheral wall 26a. In the case of the present embodiment, the plurality of extending portions 51 are arranged so as to be positioned on the radially outer side of the plurality of brake pressing portions 45, respectively, and the outer periphery of the portion where the plurality of slits 50a of the annular plate portion 50 are formed. It extends backward from the part.

  The plurality of locking flange portions 52 are arranged at appropriate intervals (equal intervals) in the circumferential direction, and are provided so as to extend radially outward from the rear end portions of the plurality of extending portions 51. The plurality of locking flange portions 52 are integrally formed with the plurality of extending portions 51 and are each formed of a vertical arc-shaped plate. The outer diameters of the plurality of locking flange portions 52 are formed to be larger than the inner diameter of the opening side end portion (front end portion) of the main body case 20 and smaller than the outer diameter. It is disposed between the front end portion of the case 20 and the outer peripheral side portion of the case cover 25 and is locked to the front end portion of the main body case 20.

  A plurality of circular arc recesses 27 with which a plurality of locking flange portions 52 are engaged from the front side are formed on the front inner surface portion of the case cover 25. These circular arc recesses 27 are formed continuously outside the outer peripheral wall 26 a of the piston cylinder part 26 in the radial direction. Although it is desirable that the depth of the arc recess 27 and the thickness of the locking flange portion 52 be the same, if the manufacturing is difficult, there is a problem even if the thickness of the locking flange portion 52 is made smaller than the depth of the arc recess 27. Absent.

  A predetermined area portion on the radially outer side of the piston cylinder portion 26 of the case cover 25 contacts the rear end portion of the main body case 20, and the opening 21 of the main body case 20 is closed by the case cover 25. The main body case 20 and the case cover 25 are connected by the bolt 29. A plurality of bolt insertion holes 29 a through which the plurality of bolts 29 are inserted are formed in the case cover 25. The case cover 25 is formed with a boss 28 that protrudes forward into the main body case 20 and through which the input shaft 2 is rotatably inserted.

The effects of the automatic transmission 1 described above are exhibited.
In the brake mechanism 30, when the brake piston 32 is driven and presses the multi-plate brake 31 toward the fastening side, the multi-plate brake 31 is fastened and the brake piston 32 is stopped driving, the brakes 32 are braked by a plurality of return springs 33. The piston 32 returns and the multi-plate brake 31 is released.

  The spring retainer 34 supports the front end portions of the plurality of return springs 33, but the outer peripheral portion of the spring retainer 34 biased by the return spring 33 is locked to the rear end portion of the main body case 20. In other words, the front end portions of the plurality of return springs 33 are reliably supported by the spring retainer 34, and the brake piston 32 is reliably urged toward the brake release side by these return springs 33.

  When the automatic transmission 1 is assembled, the parts such as the speed change mechanism 4 are assembled with the opening 21 of the main body case 20 facing upward, and finally the case cover 25 is assembled to the main body case 20. In the state where the plurality of brake pressing portions 45 of the brake piston 32 are inserted into the plurality of slits 50 a of the spring retainer 34, the plurality of extending portions 51 of the spring retainer 34 are connected to the outer periphery of the piston cylinder portion 26 of the case cover 25. The case cover 25, the brake piston 32, the plurality of return springs 33, and the spring retainer 34 can be assembled as subassemblies by temporarily fixing to the outer peripheral surface of the wall 26a.

  According to the automatic transmission 1, the plurality of locking flange portions 52 on the outer peripheral portion of the spring retainer 34 of the brake mechanism 30 are locked to the rear end portion of the main body case 20. The front end of the return spring 33 can be reliably supported, and the snap ring and the ring groove for mounting the snap ring, which are conventionally required for locking the spring retainer, can be omitted. Therefore, the number of parts can be reduced, the structure can be simplified, the assembly load can be reduced, and the opening 21 of the main body case 20 can be reduced in diameter to improve the rigidity of the transmission case 20. .

  Since the plurality of locking flange portions 52 are arranged between the rear end portion of the main body case 20 and the outer peripheral side portion of the case cover 25 and engaged with the plurality of circular arc recesses 27 formed in the case cover 25, the spring The movement of the retainer 34 in the axial direction and the circumferential direction can be regulated to prevent rattling. The spring retainer 34 is provided with a plurality of extending portions 51 at appropriate intervals in the circumferential direction, and a plurality of locking flange portions 52 are provided so as to extend outward from the plurality of extending portions 51. The structure of the locking flange portion 52 is simplified, the weight of the spring retainer 34 is reduced, and the material cost can be reduced.

  Since the plurality of return springs 33 are disposed symmetrically with respect to the plurality of brake pressing portions 45 in the circumferential direction, the multi-plate brake 31 may be uniformly pressed by the plurality of brake pressing portions 45. The plurality of return springs 33 can uniformly bias the brake piston 32, and the plurality of brake pressing portions 45 and the return springs 33 can be arranged in the radial direction in a compact manner. It becomes possible to reduce the size.

  Since the annular plate portion 50 of the spring retainer 34 is disposed between the piston portion 40 of the brake piston 32 and the multi-plate brake 31, the annular plate portion 50 reliably supports the front end portions of the plurality of return springs 33. be able to.

  Since the plurality of arc-shaped slits 50a through which the plurality of brake pressing portions 45 are respectively inserted are formed in the annular plate portion 50, the annular plate portion 50 can be provided to face the piston portion 40 of the brake piston 32, The annular plate portion 50 (spring retainer 34) and the brake piston 32 can be configured compactly.

  Since the front end portions of the plurality of return springs 33 are fixed to the spring retainer 34, and the plurality of extending portions 51 that can be temporarily fixed when the automatic transmission is assembled are provided on the outer peripheral surface of the outer peripheral wall 26a of the piston cylinder portion 26. In addition, the case cover 25, the brake piston 32, the plurality of return springs 33, and the spring retainer 34 can be easily sub-assembled when assembled, and the assemblability can be greatly improved.

  As shown in FIG. 7, the automatic transmission 1 </ b> A is obtained by changing the spring retainer 34 and the case cover 25 of the brake mechanism 30 in the automatic transmission 1 of the first embodiment. In the spring retainer 34A of the brake mechanism 30A, one extending portion 51A is provided in an annular shape (entire circumference), and one locking flange portion 52A is provided in an entire circumference (annular shape). In the spring retainer 34A, the annular plate portion 50 and the slit 50a have the same structure as that of the spring retainer 34 of the first embodiment.

  The extending portion 51A is integrally formed with the annular plate portion 50 and formed in a cylindrical shape extending rearward from the outer peripheral portion of the annular plate portion 50, and the locking flange portion 52A is integrally formed with the extending portion 51A. It is provided in an annular shape so as to extend radially outward from the rear end portion of 51A.

  The locking flange portion 52 </ b> A is disposed between the front end portion of the main body case 20 and the outer peripheral side portion of the case cover 25 </ b> A and is locked to the front end portion of the main body case 20. Here, instead of the plurality of circular arc recesses 27, an annular recess 27 </ b> A that engages the locking flange 52 </ b> A from the front side is formed on the front inner surface portion of the case cover 25 </ b> A. The structure of the case cover 25A other than the annular recess 27A is the same as that of the case cover 25 of the first embodiment.

  By providing the spring retainer 34A with the extending portion 51A in an annular shape and the locking flange portion 52A in an annular shape, the strength and rigidity of the spring retainer 34A increases, and the reliability of the spring retainer 34A increases. In addition, the same effects as those of the first embodiment are obtained.

  As shown in FIG. 8, the automatic transmission 1B is obtained by changing the main body case 20 and the case cover 25 of the first embodiment. The case cover 25B is obtained by omitting the plurality of arc concave portions 27 of the case cover 25 of the first embodiment, and a plurality of arc concave portions 27B corresponding to the plurality of arc concave portions 27 are formed at the rear end portion of the main body case 20B. The main body case 20B is formed to be continuous with the inner peripheral end. The plurality of locking flange portions 52 are engaged with the plurality of arc concave portions 27B formed in the main body case 20B, thereby restricting the movement of the spring retainer 34 in the axial direction and the circumferential direction, thereby causing rattling. It can be surely prevented.

In addition to the first to third embodiments, the following modifications may be made.
About the brake press part 45 of the brake piston 32, the extension part 51 of the spring retainer 34, and the latching flange part 52, the structure including number, arrangement | positioning, and a shape can each be changed suitably. For example, in the first embodiment, the plurality of extending portions 51 may be arranged at positions shifted in the circumferential direction with respect to the plurality of slits 50a, or the plurality of extending portions 51 and the plurality of locking flange portions. 52 may be individually extended from the annular plate portion 50.

  In addition, when it is difficult to manufacture the recesses 27, 27A, 27B with the same depth as the locking flanges 52, 52A, the locking flanges 52, 52A can be compressed and deformed (for example, elastic It may be engaged with the recesses 27, 27A, 27B via spacers. In this case, the locking flange portions 52, 52A can be securely clamped between the rear end portions of the main body cases 20, 20B and the outer peripheral side portions of the case covers 20, 20A, 20B.

  In addition, various modifications other than the above-described disclosure can be added without departing from the spirit of the present invention, and the present invention can be applied to various automatic transmissions.

1 is a skeleton diagram schematically illustrating an automatic transmission according to a first embodiment. FIG. It is a chart which shows the state of a plurality of friction engaging elements about a plurality of gear stages of a speed change mechanism. It is a longitudinal cross-sectional view of the principal part of an automatic transmission. It is a disassembled perspective view of a case cover, a brake piston, and a spring retainer. It is a disassembled side view of a case cover, a brake piston, and a spring retainer. It is a front view of a case cover, a brake piston, and a spring retainer. FIG. 6 is a diagram corresponding to FIG. FIG. 6 is a longitudinal sectional view of a main part of an automatic transmission according to a third embodiment.

Explanation of symbols

1, 1A, 1B Automatic transmission 2 Input shaft 3 Output gear 4 Transmission mechanism 5 Transmission case 20 Main body case 21 Opening portion 25 Case cover 26 Piston cylinder portion 26a Outer peripheral wall 30, 30A Brake mechanism 31 Multi-plate brake 32 Brake piston 33 Return spring 34, 34A Spring retainer 40 Piston part 45 Brake pressing part 50 Annular plate part 50a Slit 51, 51A Extension part 52, 52A Locking flange part

Claims (7)

An input shaft to which the output of the engine is input, an output member that outputs driving force to the wheels, a transmission mechanism that is interposed between the input shaft and the output member, and a transmission case that houses the transmission mechanism In an automatic transmission with
The transmission case has a main body case in which an opening is formed at an end opposite to the engine, and a case cover that closes the opening of the main body case,
The speed change mechanism includes a brake mechanism disposed in the vicinity of the opening of the main body case,
The brake mechanism includes a multi-plate brake, a brake piston that is attached to the case cover and presses the multi-plate brake toward the fastening side, a plurality of return springs that urge the brake piston toward the brake release side, and the return springs. A spring retainer that supports the multi-plate brake side end,
An automatic transmission characterized in that an outer peripheral portion of the spring retainer is locked to an opening side end portion of the main body case.   The spring retainer includes one or a plurality of locking flange portions that are disposed between the opening side end portion of the main body case and the outer peripheral side portion of the case cover and locked to the opening side end portion of the main body case. The automatic transmission according to claim 1, further comprising:   The brake piston includes a piston portion and a plurality of arc-shaped brake pressing portions provided on the piston portion at appropriate circumferential intervals and extending toward the multi-plate brake, and the plurality of return springs include The automatic transmission according to claim 2, wherein the automatic transmission is disposed at a position shifted in a circumferential direction with respect to the plurality of brake pressing portions.   The spring retainer has an annular plate portion with which the multiple plate brake side ends of the plurality of return springs abut, and the annular plate portion is disposed between the piston portion and the multiple plate brake. The automatic transmission according to claim 3.   The automatic transmission according to claim 4, wherein a plurality of arc-shaped slits through which the plurality of brake pressing portions are inserted are formed in the annular plate portion.   The automatic transmission according to any one of claims 2 to 5, wherein end portions of the plurality of return springs on the multi-plate brake side are fixed to the spring retainer. The case cover is provided with an annular piston cylinder portion protruding into the main body case,
The spring retainer has one or a plurality of extending portions that can be temporarily fixed when the automatic transmission is assembled on the outer peripheral surface of the outer peripheral wall of the piston cylinder portion, and extends from the extended portion to the outside. The automatic transmission according to any one of claims 2 to 6, wherein a plurality of locking flange portions are provided.

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