JP2012211665A - Frictional engagement device, and assembling method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the assembly workability of a frictional engagement device and suppress the increase of an axial length.SOLUTION: In a brake B1, free ends of a plurality of return springs RS supported by a spring seat 60 are brought into contact with the spring contact part 56 of a piston 50. The spring seat 60 is supported in the axial direction by the spline tooth 22s of a transaxle case 22a. The piston 50 has a snap ring 57 facing the spring seat 60 with an interval d in the axial direction on first and second friction plates 41, 42 sides from the spring seat 60 supported by the spline tooth 22s of the transaxle case 22a.

Description

  The present invention includes a first friction plate fitted to the case, a second friction plate fitted to the brake hub and frictionally engageable with the first friction plate, and moved in the axial direction with respect to the case. The present invention relates to a friction engagement device including a piston capable of pressing first and second friction plates, and a return spring unit that urges the pistons away from the first and second friction plates, and an assembling method thereof.

  Conventionally, a transmission including first and second brakes as a friction engagement device is known (see, for example, Patent Document 1). The first brake of the transmission is slidable by a friction plate that is slidably supported in the axial direction by a spline formed on the inner peripheral surface of the annular case, and a brake hub fixed to the fastening target element. And an annular piston that is slidably supported in the axial direction by a rear case that forms a transmission case together with the case, and that can move in the axial direction relative to the case and press the friction plate. And a plurality of return springs each having one end supported by a spring seat and biasing the piston in the axial direction so as to be separated from the friction plate. The second brake is slidably supported by a friction plate supported slidably in the axial direction by a spline formed on the inner peripheral surface of the case, and a brake hub fixed to the fastening target element. A friction plate, an annular piston that is slidably supported in the axial direction by the case and that can move in the axial direction relative to the case and press the friction plate, and one end thereof is supported by a spring seat. A plurality of return springs that urge the piston in the axial direction so as to be separated from the friction plate, and an oil chamber defining member that defines an oil chamber behind the piston.

  When assembling the first brake described above, the piston is fitted into the rear case, and the free ends (the other ends) of the plurality of return springs, one end of which is supported by the spring seat, are connected to the spring contact portion formed on the piston. At the same time, the spring seat is fixed to the rear case using a snap ring. Then, by fixing the rear case integrated with the piston, the return spring, and the spring seat to the case, the piston is made to face the friction plate supported by the case. Further, when the second brake is assembled, a spring seat supporting a plurality of return springs is fitted to the piston, and the piston is fitted to the hydraulic chamber defining member. The piston integrated with the return spring, the spring seat, and the hydraulic chamber defining member is brought into contact with the spring contact portion formed on the end plate supported by the case at the free end (the other end) of the return spring. By disposing in the case, the piston faces the friction plate supported by the case.

JP-A-10-281239

  However, when the spring seat supporting the plurality of return springs is fixed to the rear case by the snap ring as in the conventional first brake, a groove for attaching the snap ring and a reinforcing portion around the groove must be formed in the rear case. In other words, the rear case, and thus the shaft length of the transmission, becomes long. In the second brake of the related art, when the piston is placed in the case, the free end (the other end) of the return spring must be abutted against the case-side spring abutting portion while visually confirming, There is still room for improvement in terms of assembly.

  In view of the above, the main object of the present invention is to improve the assembly of the friction engagement device and to suppress an increase in the axial length.

  The friction engagement device and the assembling method thereof according to the present invention employ the following means in order to achieve the main object.

The friction engagement device of the present invention includes:
A first friction plate fitted to the case; a second friction plate fitted to the brake hub and frictionally engageable with the first friction plate; and A piston capable of pressing the first and second friction plates, and an outer peripheral side of the pressing portion of the piston that contacts the first or second friction plate, and one end in the axial direction contacts the case and the A friction engagement device comprising: a return spring unit that abuts the other end in the axial direction in contact with the piston and biases the piston away from the first and second friction plates;
A retaining member that is attached to the piston on the first and second friction plate sides with respect to the contact surface between the case and the return spring unit and prevents the return spring unit from coming off the piston in the axial direction. It is characterized by having.

  In this friction engagement device, the return spring unit that urges the piston so as to be separated from the first and second friction plates is disposed on the outer peripheral side of the pressing portion of the piston that contacts the first or second friction plate, One end of the return spring unit in the axial direction is in contact with the case, and the other end in the axial direction is in contact with the piston. The friction engagement device is attached to the piston on the first and second friction plate sides with respect to the contact surface between the case and the return spring unit, and the return spring unit is prevented from coming off from the piston in the axial direction. It has a stop member. In assembling such a friction engagement device, the other end of the return spring unit is brought into contact with the piston, and one end of the return spring unit is brought into contact with the retaining member. As a result, the return spring unit is prevented from coming off (temporarily fixed) with respect to the piston so as not to come off from the piston in the axial direction, and the piston and the return spring unit are integrated. When the piston is assembled to the case, one end of the return spring unit is brought into contact with the case and the piston is pushed toward the case to compress the return spring in the axial direction. Thus, even if the return spring unit and the retaining member are in contact with each other when the end of the return spring unit is in contact with the case, the return spring unit is compressed as the piston moves, so that the return spring unit is compressed. The spring unit is separated from the retaining member. Accordingly, the retaining (temporary retaining) of the return spring unit with respect to the piston is released, and the retaining member is positioned closer to the first and second friction plates than the contact surface between the case and the return spring unit. Become.

  As a result, the return spring unit can be easily secured (temporarily secured) to the piston, and the piston or return spring unit can be attached to the case without any visual confirmation required for alignment of the return spring unit. Therefore, the assembling property of the frictional engagement device can be improved. Further, by supporting the return spring unit in the axial direction by the case, an increase in the axial length of the friction engagement device can be easily suppressed. Furthermore, in order to ensure the operation of the friction engagement device, it is general to provide a certain margin in the axial length of the piston. Further, the retaining member attached to the piston does not participate in the operation of the friction engagement device after the assembly of the friction engagement device is completed, and the holding capacity of the return spring unit required for the retaining member is not so much. not high. Therefore, it can be said that there is no substantial increase in the axial length of the piston due to the installation of the retaining member.

  In addition, the pressing portion of the piston may have an annular pressing surface that can come into contact with one of the first and second friction plates, and the other end of the return spring unit is more than the pressing surface. May contact the piston on the outer peripheral side. Since such a piston can press the first and second friction plates with the entire annular pressing surface, the seizure between the pressing surface and the friction plate can be satisfactorily suppressed, while the back side of the piston This makes it very difficult to align the return spring unit visually. Therefore, if the present invention is applied to a friction engagement device including a piston having such a configuration, the return spring unit can be easily retained (temporarily secured) with respect to the piston, and the return spring unit can be aligned. The piston can be easily assembled to the case without performing the required visual confirmation work. As a result, it is possible to obtain a friction engagement device that has good assemblability and can suppress an increase in the axial length and can well suppress seizure between the pressing surface and the friction plate.

  Furthermore, the retaining member may be a snap ring attached to the piston. Accordingly, it is possible to easily attach the retaining member to the piston after the other end of the return spring unit is brought into contact with the piston, and it is possible to suppress an increase in cost due to the installation of the retaining member with respect to the piston.

  Further, the case may be formed in an annular shape, and a spline on which the first friction plate is fitted may be formed on an inner peripheral surface of the case, and the one end of the return spring unit is You may contact | abut with the one end part of the said spline. That is, in order to ensure the operation of the frictional engagement device, it is common to provide a certain margin in the axial length of the spline, so one end of the spline formed on the inner peripheral surface of the case in this way And the one end of the return spring unit are brought into contact with each other, an increase in the axial length of the case can be suppressed or the axial length of the case can be shortened.

  Further, the case may include a first case in which the first friction plate is fitted, and a second case that is coupled to the first case and that slidably supports the piston. Good. As a result, the return spring unit is disposed with respect to the piston supported by the second case, and the return spring unit is fixed to the second case by the snap ring, so that the snap ring is not attached to the second case. Since the axial length of the second case can be shortened, it is possible to shorten the axial length of the friction engagement device.

  Further, the case may be a transmission case that constitutes a transmission, or may be configured as a brake that can fix a rotating element of the transmission to the transmission case.

The method for assembling the friction engagement device according to the present invention includes:
A first friction plate fitted to the case; a second friction plate fitted to the brake hub and frictionally engageable with the first friction plate; and A piston capable of pressing the first and second friction plates, and an outer peripheral side of the pressing portion of the piston that contacts the first or second friction plate, and one end in the axial direction contacts the case and the Friction engagement device comprising: a friction engagement device comprising a return spring unit that abuts the other end in the axial direction in contact with the piston and biases the piston away from the first and second friction plates In the assembly method of
(A) contacting the other end of the return spring unit with the piston and preventing the return spring unit from coming off from the piston in the axial direction;
(B) When the piston is assembled to the case, the one end of the return spring unit is brought into contact with the case and the piston is pushed toward the case to compress the return spring unit in the axial direction. Releasing the retainer for the return spring unit with respect to the piston;
Is included.

  According to this method, the return spring unit can be easily retained (temporarily fixed) on the piston, and the piston and return spring unit can be mounted without performing visual confirmation work required for alignment of the return spring unit. Since it can be easily assembled to the case, the assemblability of the friction engagement device can be improved. Further, by supporting the return spring unit in the axial direction by the case, an increase in the axial length of the friction engagement device can be easily suppressed.

It is a schematic block diagram of the motor vehicle 10 carrying the power transmission device 20 containing the automatic transmission 30 which has brake B1 which is a friction engagement apparatus based on the Example of this invention. 2 is a schematic configuration diagram of a power transmission device 20. FIG. 3 is an operation table showing the relationship between each gear position of the automatic transmission 30 and the operation states of clutches and brakes. 2 is an enlarged view showing a main part of the automatic transmission 30. FIG. 2 is an enlarged view showing a brake B1 of the automatic transmission 30. FIG. 2 is a front view of a piston 00 of a brake B1 included in an automatic transmission 30. FIG. (A) And (b) is an enlarged view which shows the assembly procedure of brake B1. (A) And (b) is an enlarged view which shows the assembly procedure of brake B1. It is an enlarged view showing brake B1 'concerning a modification. It is an enlarged view showing brake B1 '' concerning a modification.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a schematic configuration diagram of an automobile 10 equipped with a power transmission device 20 including an automatic transmission 30 having a brake B1, which is a friction engagement device according to an embodiment of the present invention, and FIG. 2 is a power transmission device. FIG. An automobile 10 shown in FIG. 1 includes an engine 12 as a prime mover, which is an internal combustion engine that outputs power by an explosion combustion of a mixture of hydrocarbon fuel such as gasoline and light oil, and air, and an engine electronic that controls the engine 12. A control unit (hereinafter referred to as “engine ECU”) 14, a brake electronic control unit (hereinafter referred to as “brake ECU”) 15 for controlling an electronically controlled hydraulic brake unit (not shown), and a fluid transmission device (starting device) 23 And a stepped automatic transmission 30, a hydraulic control device 70 that supplies and discharges hydraulic oil (working fluid) to these, a shift electronic control unit (hereinafter referred to as “shift ECU”) 21 that controls these, and the like, A power transmission device 20 is connected to the crankshaft 16 of the engine 12 and transmits power from the engine 12 to the left and right drive wheels DW. Equipped with a. The engine ECU 14, the brake ECU 15 and the transmission ECU 21 are all configured as a microcomputer centered on a CPU (not shown). In addition to the CPU, a ROM for storing various programs, a RAM for temporarily storing data, and an input / output port And a communication port (both not shown). The engine ECU 14, the brake ECU 15 and the transmission ECU 21 are connected to each other via a bus line or the like, and exchange of data necessary for control is executed between these ECUs as needed.

  The engine ECU 14 includes a crankshaft (not shown) that detects the accelerator opening Acc from the accelerator pedal position sensor 92 that detects the depression amount (operation amount) of the accelerator pedal 91, the vehicle speed V from the vehicle speed sensor 99, and the rotation of the crankshaft 16. Signals from various sensors such as position sensors, signals from the brake ECU 15 and the shift ECU 21 and the like are input, and the engine ECU 14 is based on these signals, and an electronically controlled throttle valve, fuel injection valve, spark plug, etc. (not shown). To control. The brake ECU 15 receives the master cylinder pressure detected by the master cylinder pressure sensor 94 when the brake pedal 93 is depressed, the vehicle speed V from the vehicle speed sensor 99, signals from various sensors (not shown), the engine ECU 14 and the transmission ECU 21. The brake ECU 15 controls a brake actuator (hydraulic actuator) (not shown) and the like based on these signals. The transmission ECU 21 of the power transmission device 20 is accommodated in the transmission case 22. The shift ECU 21 includes a shift range SR from a shift range sensor 96 that detects an operation position of a shift lever 95 for selecting a desired shift range from a plurality of shift ranges, a vehicle speed V from a vehicle speed sensor 99, and not shown. Signals from various sensors, signals from the engine ECU 14 and brake ECU 15, and the like are input, and the transmission ECU 21 controls the fluid transmission device 23, the automatic transmission 30, and the like based on these signals.

  The power transmission device 20 includes a fluid transmission device 23 housed in the transmission case 22, an oil pump 29 as an oil pressure generation source, an automatic transmission 30, and the like. The fluid transmission device 23 is configured as a fluid torque converter with a lock-up clutch, and as shown in FIG. 2, a pump impeller 24 connected to the crankshaft 16 of the engine 12 via the front cover 18 and a turbine The turbine runner 25 fixed to the input shaft (power input member) 31 of the automatic transmission 30 via the hub, the pump impeller 24, and the hydraulic oil from the turbine runner 25 to the pump impeller 24 (inside the turbine runner 25) A stator 26 that rectifies the flow of ATF), a one-way clutch 27 that restricts the rotation direction of the stator 26 to one direction, a lock-up clutch 28 having a damper mechanism (not shown), and the like. The fluid transmission device 23 functions as a torque amplifier due to the action of the stator 26 when the rotational speed difference between the pump impeller 24 and the turbine runner 25 is large, and functions as a fluid coupling when the rotational speed difference between the two is small. The lock-up clutch 28 is capable of executing lock-up that directly connects the front cover 18 and the input shaft 31 of the automatic transmission 30 and release of the lock-up. When a predetermined lock-up on condition is satisfied after the vehicle 10 is started, the front cover 18 and the input shaft 31 of the automatic transmission 30 are directly connected (locked up) by the lock-up clutch 28, and the power from the engine 12 is transmitted. It is transmitted mechanically and directly to the input shaft 31. At this time, fluctuations in torque transmitted to the input shaft 31 are absorbed by a damper mechanism (not shown).

  The oil pump 29 as a hydraulic pressure generation source is configured as a gear pump including a pump assembly including a pump body and a pump cover, and an external gear connected to the pump impeller 24 of the fluid transmission device 23 via a hub. , Connected to the hydraulic control device 70. When the engine 12 is in operation, the external gear is rotated by the power from the engine 12, whereby the hydraulic oil stored in the oil pan (not shown) is sucked by the oil pump 29 through the strainer. And is discharged from the oil pump 29. Therefore, during operation of the engine 12, the oil pump 29 can generate the hydraulic pressure required by the fluid transmission device 23 and the automatic transmission 30, and supply hydraulic oil to lubricated parts such as various bearings. .

  The automatic transmission 30 is configured as a four-stage transmission, and as shown in FIG. It includes clutches C1, C2 and C3, two brakes B1 and B3, and a one-way clutch F2. The Ravigneaux type planetary gear mechanism 32 includes two sun gears 33a and 33b which are external gears, a ring gear 34 which is an internal gear fixed to an output shaft (power output member) 37 of the automatic transmission 30, and a sun gear 33a. A plurality of short pinion gears 35a meshing with each other, a plurality of long pinion gears 35b meshing with the sun gear 33b and the plurality of short pinion gears 35a and meshing with the ring gear 34, and a plurality of short pinion gears 35a and a plurality of long pinion gears 35b connected to each other are rotated. And a carrier 36 that is held to revolve freely and is supported by the transmission case 22 via a one-way clutch F2. The output shaft 37 of the automatic transmission 30 is connected to the drive wheels DW via a gear mechanism 38 and a differential mechanism 39.

  The clutch C1 is a hydraulic clutch that can fasten the input shaft 31 and the sun gear 33a of the Ravigneaux type planetary gear mechanism 32 and release the fastening of the two. The clutch C2 is a hydraulic clutch that can fasten the input shaft 31 and the carrier 36 of the Ravigneaux type planetary gear mechanism 32 and can release the fastening of both. The clutch C3 is a hydraulic clutch that can fasten the input shaft 31 and the sun gear 33b of the Ravigneaux type planetary gear mechanism 32 and release the fastening of both. The brake B1 is a hydraulic clutch capable of fixing the sun gear 33b of the Ravigneaux type planetary gear mechanism 32 to the transmission case 22 and releasing the sun gear 33b from the transmission case 22. The brake B3 is a hydraulic clutch that can fix the carrier 36 of the Ravigneaux type planetary gear mechanism 32 to the transmission case 22 and release the carrier 36 from the transmission case 22. The clutches C1 to C3 and the brakes B1 and B3 operate upon receiving and supplying hydraulic oil from the hydraulic control device 70. FIG. 3 shows an operation table showing the relationship between the respective speeds of the automatic transmission 30 and the operating states of the clutches C1 to C3, the brakes B1 and B3, and the one-way clutch F2. The automatic transmission 30 provides the first to fourth forward speeds and the first reverse speed by setting the clutches C1 to C3 and the brakes B1 and B3 to the states shown in the operation table of FIG.

  Next, the brake B1 of the automatic transmission 30 will be described in detail. 4 is an enlarged view of a main part of the automatic transmission 30, and FIG. 5 is an enlarged view showing the brake B1.

  As described above, the brake B1 is used to fix the sun gear 33b of the Ravigneaux type planetary gear mechanism 32 to the transmission case 22 when the second speed or the fourth speed of the automatic transmission 30 is formed. As shown in FIG. 4, the clutches C1 and C3 are arranged on the outer peripheral side. The brake B1 engages with a plurality of spline teeth (splines) 22s formed on the inner peripheral surface of a transaxle case (first case) 22a constituting the transmission case (first friction plate support member) 22. A Ravigneaux type planetary gear mechanism which is disposed between a plurality of first friction plates (mating plates) 41 slidably supported by the transaxle case 22a and the first friction plates 41 adjacent to each other and which is to be fastened. 32 is engaged with a plurality of spline teeth (splines) 44s formed on the outer peripheral surface of a brake hub (second friction plate support member) 44 fixed to a sun gear (element to be fastened) 33b. It is configured as a multi-plate hydraulic brake including a plurality of second friction plates (members having friction materials on both sides) 42 that are movably supported.

  As shown in FIGS. 4 and 5, the brake B1 is in addition to the plurality of first friction plates 41 supported by the transaxle case 22a and the plurality of second friction plates 42 supported by the brake hub 44 on the fastening target side. The piston 50 can move in the axial direction with respect to the transaxle case 22a and can press the first and second friction plates 41 and 42, and one end of each is supported (clamped) by the spring seat 60 and the piston 50 And a plurality of return springs RS that are urged in the axial direction so as to be separated from the first and second friction plates 41, 42. The spring seat 60 and the plurality of return springs RS are integrated to form a return spring unit.

  As shown in FIG. 4, the piston 50 is an annular body that is slidably supported by a rear case (second case) 22 b that is fastened (connected) to the transaxle case 22 a and constitutes the transmission case 22. A small-diameter cylindrical portion 51 and a large-diameter cylindrical portion 52 that are in sliding contact with the corresponding inner peripheral surface of 22b, and an annular pressing surface 53a that extends from the large-diameter cylindrical portion 52 toward the transaxle case 22a (on the right side in the figure). And a pressing cylinder 53 having a free end. As shown in FIGS. 4 and 5, the inner peripheral surface of the rear case 22b, the outer peripheral surface of the small-diameter cylindrical portion 51, and the back surface of the large-diameter cylindrical portion 52 receive hydraulic pressure from a linear solenoid valve (not shown) when the brake B1 is engaged. The oil chamber 54 to be supplied is defined. Further, as shown in FIGS. 5 and 6, the piston 50 includes a plurality of pistons 50 that extend outward from the large-diameter cylindrical portion 52 and the pressing cylindrical portion 53 at equal intervals (in the embodiment, 4 at 90 ° intervals). ) Extending portions 55. On the surface of each extending portion 55 (on the right side in FIG. 5, that is, on the first and second friction plates 41 and 42 side), a spring contact that is a circular recess that can be engaged with the free end (the other end) of the return spring RS. A plurality of contact portions 56 are formed. Each spring contact portion 56 is located on the outer peripheral side of the pressing surface 53 a of the pressing cylindrical portion 53.

  As shown in FIG. 5, in the attached state of the piston 50, that is, in the state where the hydraulic pressure is not supplied to the oil chamber 54, a diagram of the pressing surface 53 a of the pressing cylindrical portion 53 and the first and second friction plates 41 and 42. A gap is formed between the first friction plate 41 located on the leftmost side. Further, in the mounted state of the piston 50, the free end (the other end) of each return spring RS supported by the spring seat 60 contacts the spring contact portion 56 of the piston 50, and the back surface of the spring seat 60 is the transaxle case. The spring seat 60 is supported in the axial direction by the spline teeth 22s by abutting against the front end surface (single axial surface) of one end of the plurality of spline teeth 22s formed on the inner peripheral surface of 22a. That is, the return spring unit including the spring seat 60 and the plurality of return springs RS is disposed on the outer periphery of the pressing cylindrical portion 53 of the piston 50. Further, as shown in the figure, the piston 50 has a snap ring 57 as a retaining member (temporary retaining member) attached to the outer periphery of the pressing cylindrical portion 53 on the free end side. Compared with the spring seat 60 and the axial direction in the first and second friction plates 41 and 42 side than the contact surface of the spring seat 6, that is, the spring seat 60 and one end of the spline teeth 22s, in the attached state of the piston 50. Opposite each other with a small distance d. The snap ring 57 does not participate in the operation of the brake B1, but is extremely useful when assembling the brake B1.

  When the hydraulic pressure from the linear solenoid valve is supplied to the oil chamber 54 when the brake B1 is engaged, the piston 50 is applied to the transaxle case 22a (first and second friction plates 41, 42) by the hydraulic pressure from the linear solenoid valve. The pressing surface 53a of the piston 50 comes into contact with the first friction plate 41 located on the leftmost side of the first and second friction plates 41, 42 in the drawing. The first and second friction plates 41 and 42 are pressed by the piston 50 and are sandwiched between the pressing surface 53a and the retaining plate 45 held by the transaxle case 22a (spline teeth 22s) to be frictionally engaged. As a result, the sun gear 33 b of the Ravigneaux type planetary gear mechanism 32 is fixed to the transmission case 22. At this time, since the piston 50 can press the first and second friction plates 41 and 42 by the entire annular pressing surface 53a, the brake B1 seizes the pressing surface 53a and the first friction plate 41. It can suppress well.

  Next, the assembly procedure of the above-described brake B1 will be described with reference to FIGS. The brake B1 is assembled in the transmission case 22 together with other components of the automatic transmission 30, but here, for the sake of simplicity, only the components of the brake B1 are taken up and the assembling procedure is described. explain.

  When the brake B1 is assembled, one end of a plurality of return springs RS is fixed to the spring seat 60 by caulking or the like, and a plurality of return springs RS supported at one end by the spring seat 60 as shown in FIG. The free end (the other end) of each is brought into contact with the spring contact portion 56 of the piston 50. Here, since the piston 50 of the embodiment has the spring contact portion 56 on the outer peripheral side of the pressing surface 53a, the free end of the return spring RS and the spring contact portion visually observed from the back side of the spring contact portion 56. In this example, the plurality of return springs RS supported by the spring seat 60 are approached from the front surface (spring contact portion 56) side of the piston 50. Therefore, the free end of each return spring RS can be easily brought into contact with the spring contact portion 56.

  When the free end of each return spring RS is brought into contact with the spring contact portion 56, as shown in FIG. 7B, while applying force from the back surface of the spring seat 60 and compressing each return spring RS, The snap ring 57 is attached to a snap ring groove formed on the outer periphery of the pressing cylindrical portion 53 of the piston 50 so as to contact the back surface of the spring seat 60. As a result, the spring seat 60 and each return spring RS (return spring unit) do not move in the axial direction with respect to the piston 50, that is, the pressing cylinder so as not to slip out from the pressing cylindrical portion 53 of the piston 50 in the axial direction. The piston 53, the plurality of return springs RS, and the spring seat 60 are integrated with each other by being temporarily fixed to the portion 53. At this time, the compression amount of each return spring RS is smaller than the compression amount in the attached state, and the holding capacity (reaction force from each return spring RS) between the spring seat 60 and the return spring RS required for the snap ring 57 is Not very expensive. The positioning of the plurality of return springs RS and the spring seat 60 with respect to the piston 50 up to this point and temporary fixing (preventing removal) may be performed manually, but are preferably performed by an assembly robot.

  If the spring seat 60 and the plurality of return springs RS are temporarily fixed (removed) with respect to the piston 50 in this way, the integrated piston 50, the plurality of return springs RS, and the spring are integrated as shown in FIG. The seat 60 is disposed (fitted) in the rear case 22b. When the piston 50 and the like are thus disposed in the rear case 22b, as shown in FIG. 8B, the back surface of the spring seat 60 (the right surface in the drawing) is in contact with the end surface of the rear case 22b (the transaxle case 22a. Projecting outward (right side in the figure). Then, the assembly including the rear case 22b and the piston 50 is attached to the assembly including the transaxle case 22a and the like. Prior to the step of attaching the rear case 22b to the transaxle case 22a, a brake hub 44 is disposed in the transaxle case 22a together with the components of the Ravigneaux type planetary gear mechanism 32 and the spline of the transaxle case 22a. The retaining plate 45 and the first and second friction plates 41 and 42 are fitted in the teeth 22 s and the spline teeth 44 s of the brake hub 44 in a predetermined order.

  When attaching the rear case 22b to the transaxle case 22a, the spring seat 60 is brought into contact with the tip surface of the spline teeth 22s as the seat support portion of the transaxle case 22a and the piston 50 together with the rear case 22b faces the transaxle case 22a. It pushes in and compresses each return spring RS to an axial direction. Thus, even when the back surface of the spring seat 60 and the snap ring 57 of the piston 50 are in contact with the spline teeth 22s of the transaxle case 22a when the back surface of the spring seat 60 is in contact with the spline teeth 22s, the rear case 22b and the piston 50 As the return spring RS is further compressed, the spring seat 60 is separated from the snap ring 57 of the piston 50. Accordingly, the temporary stop (prevention of retaining) of the spring seat 60 or the like with respect to the piston 50 is released, and the snap ring 57 is closer to the first and second friction plates 41 and 42 than the spring seat 60 as shown in FIG. Thus, the spring seat 60 is opposed to the spring seat 60 with an interval d in the axial direction. By fastening the rear case 22b to the transaxle case 22a, the assembly of the brake B1 is completed together with the mounting of the assembly including the rear case 22b and the piston 50 to the assembly including the transaxle case 22a. .

  As described above, the brake B1 of the automatic transmission 30 according to the embodiment includes the first friction plate 41 slidably supported by the transaxle case (first friction plate support member) 22a and the brake on the fastening target side. A second friction plate 42 slidably supported by a hub (second friction plate support member) 44 and frictionally engageable with the first friction plate 41, and moved in the axial direction with respect to the transaxle case 22a. A piston 50 capable of pressing the first and second friction plates 41 and 42 and one end thereof are supported by a spring seat 60 and the piston 50 is separated from the first and second friction plates 41 and 42 in the axial direction. And a plurality of return springs RS to be urged. In the brake B1, the other ends of the plurality of return springs RS are in contact with the spring contact portion 56 of the piston 50, and the spring seat 60 is supported in the axial direction by the spline teeth 22s of the transaxle case 22a. Further, the piston 50 has the first and second friction plates 41, more than the spring seat 60 supported by the spline teeth 22s of the transaxle case 22a, that is, the contact surface between the spring seat 60 and one end of the spline teeth 22s. On the side 42, a snap ring 57 that faces the spring seat 60 in the axial direction is provided.

  When assembling such a brake B1, the other ends of the plurality of return springs RS, one end of which is supported by the spring seat 60, are brought into contact with the spring contact portion 56 of the piston 50, and the spring seat 60 is attached to the piston 50. The return spring unit composed of the spring seat 60 and the plurality of return springs RS is brought into contact with the snap ring 57 thus temporarily fixed (prevented from coming off) to the piston 50 so as not to move in the axial direction with respect to the piston 50. Further, when the piston 50 is assembled to the transaxle case 22a, the spring seat 60 is brought into contact with the spline teeth 22s of the transaxle case 22a, and the piston 50 is pushed toward the transaxle case 22a so that the return spring RS is axially moved. It compresses and cancels | releases the temporary stop (detachment prevention) with respect to the piston 50 of the spring seat 60 and the return spring RS.

  Accordingly, the plurality of return springs RS and the spring seat 60 (return spring unit) are easily temporarily fixed (prevented from coming off) to the piston 50, and then required for alignment between the return spring RS and the spring contact portion 56. Since it is possible to easily assemble the piston 50, the return spring RS, etc. (return spring unit) to the transaxle case 22a without performing such visual confirmation work, the assembly of the brake B1 can be improved. it can. Further, by supporting the spring seat 60 supporting the plurality of return springs RS in the axial direction by the spline teeth 22s of the transaxle case 22a, it is possible to easily suppress an increase in the axial length of the brake B1 and thus the automatic transmission 30. it can. Furthermore, in order to ensure the operation of the brake B1, it is common to provide a certain margin in the axial length of the piston 50. Further, the snap ring 57 of the piston 50 is not involved in the operation of the brake B1 after the assembly of the brake B1 is completed, and the holding capability of the spring seat 60 and the return spring RS required for the snap ring 57 is the above-mentioned. Not so high. Therefore, it can be said that there is no substantial increase in the axial length of the piston 50 due to the installation of the snap ring 57 on the pressing cylindrical portion 53, that is, the formation of the groove in which the snap ring 57 is mounted or the reinforcing portion around the groove. .

  Further, the piston 50 of the embodiment includes an annular pressing surface 53a that can be in contact with one of the first and second friction plates 41 and 42, and a plurality of spring contact portions that are formed on the outer peripheral side of the pressing surface 53a. 56. Since such a piston 50 can press the first and second friction plates 41 and 42 by the entire annular pressing surface 53a, the seizure between the pressing surface 53a and the first friction plate 41 in contact with the pressing surface 53a is excellent. On the other hand, it is extremely difficult to align the free end of the return spring RS and the spring contact portion 56 by visual observation from the back side of the spring contact portion 56. Accordingly, if a temporary fastening structure (a retaining structure) using the snap ring 57 as described above is applied to the brake B1 including the piston 50 having such a configuration, a plurality of return springs RS and spring seats 60 are applied to the piston 50. After the (return spring unit) is easily temporarily fixed (prevented from coming off), the piston 50 can be attached to the transaxle case without performing a visual check operation required for alignment between the return spring and the spring contact portion 56. It can be easily assembled to 22a. As a result, it is possible to obtain a brake B1 that has good assemblability and can suppress an increase in the axial length and can satisfactorily suppress seizure between the pressing surface 53a and the first friction plate 41. .

  Further, if the snap ring 57 is used as a retaining member as in the above embodiment, the free ends (the other ends) of the plurality of return springs RS are brought into contact with the spring contact portions 56 of the piston 50 and then come out into the piston 50. The stopper member can be easily installed, and the cost increase associated with the installation of the stopper member to the piston 50 can be suppressed. However, the retaining member of the piston 50 may be constituted by a member other than the snap ring 57. For example, a minute protrusion may be formed on the outer periphery of the pressing cylindrical portion 53 of the piston 50.

  In addition, in order to ensure the operation of the brake B1, the axial length of the spline teeth 22s formed on the inner peripheral surface of the transaxle case 22a is generally given a certain amount of margin. If the spring seat 60 is supported by the tip surface (one end portion) of the spline teeth 22s formed on the inner peripheral surface of the transaxle case 22a, the transaxle case associated with the installation of the member (part) that supports the spring seat 60 is provided. As a result, an increase in the shaft length of the automatic transmission 30 can be suppressed, or the shaft length can be shortened.

  Further, as described above, the connecting portion (joint) between the transaxle case 22a that supports the first friction plate 41 and the rear case 22b that is fastened (connected) to the transaxle case 22a and that slidably supports the piston 50. If the retaining structure (temporary retaining structure) using the snap ring 57 is applied to the brake B1 arranged so as to straddle the part), a plurality of pistons supported by the rear case are supported by the spring seat. The axial length of the rear case 22b is shortened by not attaching the snap ring 57 to the rear case 22b as compared with the case where the return spring is arranged and the spring seat is fixed to the rear case by the snap ring (refer to the first brake of Patent Document 1). So that the brake B1 and automatic To shorten the axial length of the speed machine 30 becomes possible.

  Note that the support portion of the spring seat 60 on the transaxle case 22a (transmission case 22) side may not be formed integrally with the transaxle case 22a such as the spline teeth 22s. That is, as in the brake B1 ′ shown in FIG. 9, the spring seat is provided by a separate member attached (fixed) to the transaxle case 22a (transmission case 22) such as the snap ring 58 attached to the inner peripheral surface of the transaxle case 22a. 60 may be supported. Further, the retaining structure (temporary retaining structure) using the snap ring 57 can be applied to other than the brake B1 disposed so as to straddle the connecting portion (joining portion) between the transaxle case 22a and the rear case 22b. . In other words, the retaining structure (temporary retaining structure) using the snap ring 57 is a brake B1 ″ (for example, the automatic transmission 30) arranged so as not to straddle the separation portion of the transmission case 22 ″ as shown in FIG. May be applied to the brake B3). Further, the application object of the retaining structure (temporary retaining structure) using the snap ring 57 is not limited to the brake B1 or the like that can fix the rotating element of the automatic transmission 30 to the transmission case 22, and the like. A clutch (multi-plate hydraulic clutch) for fastening the rotating elements may be used. Moreover, you may make the free end of each return spring RS contact | abut with the spring contact part 56 of the piston 50 via another member (for example, spring seat).

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. That is, in the above embodiment, the first friction plate 41 fitted to the transmission cases 22 and 22 ″, and the second friction plate 42 fitted to the brake hub 44 and frictionally engageable with the first friction plate 41. A piston 50 that can move in the axial direction with respect to the transmission case 22, 22 ″ to press the first and second friction plates 41, 42, and a pressing cylindrical portion 53 of the piston 50 that contacts the first friction plate 41. And one end in the axial direction is in contact with the transmission case 22, 22 ″ and the other end in the axial direction is in contact with the piston 50, and the piston 50 is separated from the first and second friction plates 41, 42. Brakes B1 and B having a plurality of return springs RS and a return spring unit composed of a spring seat 60. ′, B1 ″ corresponds to a “friction engagement device”, and the first and second friction plates 41, 42 are located on the contact surface between the spring seat 60 and one end of the spline teeth 22s (transmission cases 22, 22 ″). A snap ring 57 that is attached to the piston 50 on the side and prevents the return spring unit including the plurality of return springs RS and the spring seat 60 from coming off from the piston 50 in the axial direction corresponds to a “retaining member”. The case 22a corresponds to a “first case”, and the rear case 22b corresponds to a “second case”. However, the correspondence relationship between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is described in the column of means for the embodiment etc. to solve the problem. The embodiment for carrying out the invention is an example for specifically explaining the embodiment, and does not limit the elements of the invention described in the column of means for solving the problem. In other words, the examples and the like are merely specific examples of the invention described in the column of means for solving the problem, and the interpretation of the invention described in the column of means for solving the problem is not limited to that column. This should be done based on the description.

  As mentioned above, although the embodiment of the present invention has been described using examples, the present invention is not limited to the above-described examples, and various modifications can be made without departing from the scope of the present invention. Needless to say.

  The present invention can be used in the manufacturing industry of friction engagement devices.

  10 automobiles, 12 engines, 14 electronic control units for engines (engine ECUs), 15 electronic control units for brakes (brake ECUs), 16 crankshafts, 18 front covers, 20 power transmission devices, 21 electronic control units for transmissions (transmission ECUs) ), 22 Transmission case, 22, 22 ″ Transmission case, 22a Transaxle case, 22b Rear case, 22s, 44s Spline teeth, 23 Fluid transmission device, 24 Pump impeller, 25 Turbine runner, 26 Stator, 27 One-way clutch, 28 Lock-up Clutch, 29 oil pump, 30 automatic transmission, 31 input shaft, 32 Ravigneaux type planetary gear mechanism, 33a, 33b sun gear, 34 ring gear, 35a show Toppinion gear, 35b Long pinion gear, 36 Carrier, 37 Output shaft, 38 Gear mechanism, 39 Differential mechanism, 41 First friction plate, 42 Second friction plate, 44 Brake hub, 45 Retaining plate, 50 Piston, 51 Small diameter cylinder Part, 52 large-diameter cylindrical part, 53 pressing cylinder part, 53a pressing surface, 54 oil chamber, 55 extension part, 56 spring contact part, 57, 58 snap ring, 60 spring seat, 70 hydraulic control device, 91 accelerator pedal , 92 Accelerator pedal position sensor, 93 Brake pedal, 94 Master cylinder pressure sensor, 95 Shift lever, 96 Shift range sensor, 99 Vehicle speed sensor, B1, B1 ', B1 ", B3 brake, C1, C2, C3 clutch, DW drive Wheel, F2 one wake Pitch, RS return spring.

Claims (7)

A first friction plate fitted to the case; a second friction plate fitted to the brake hub and frictionally engageable with the first friction plate; and A piston capable of pressing the first and second friction plates, and an outer peripheral side of the pressing portion of the piston that contacts the first or second friction plate, and one end in the axial direction contacts the case and the A friction engagement device comprising: a return spring unit that abuts the other end in the axial direction in contact with the piston and biases the piston away from the first and second friction plates;
A retaining member that is attached to the piston on the first and second friction plate sides with respect to the contact surface between the case and the return spring unit and prevents the return spring unit from coming off the piston in the axial direction. A friction engagement device comprising: The friction engagement device according to claim 1,
The pressing portion of the piston has an annular pressing surface that can come into contact with one of the first and second friction plates, and the other end of the return spring unit is on the outer peripheral side of the pressing surface. A frictional engagement device that abuts on a piston. The friction engagement device according to claim 1 or 2,
The frictional engagement device, wherein the retaining member is a snap ring attached to the piston. In the friction engagement device according to any one of claims 1 to 3,
The case is formed in an annular shape, and a spline on which the first friction plate is fitted is formed on an inner peripheral surface of the case, and the one end of the return spring unit is one end of the spline. A frictional engagement device, wherein the frictional engagement device is in contact with a portion. The friction engagement device according to claim 4, wherein
The case includes a first case in which the first friction plate is fitted, and a second case connected to the first case and slidably supporting the piston. Combined device. The friction engagement device according to claim 4 or 5,
The case is a transmission case constituting a transmission,
A friction engagement device characterized in that the rotation element of the transmission is configured as a brake that can be fixed to the transmission case. A first friction plate fitted to the case; a second friction plate fitted to the brake hub and frictionally engageable with the first friction plate; and A piston capable of pressing the first and second friction plates, and an outer peripheral side of the pressing portion of the piston that contacts the first or second friction plate, and one end in the axial direction contacts the case and the Friction engagement device comprising: a friction engagement device comprising a return spring unit that abuts the other end in the axial direction in contact with the piston and biases the piston away from the first and second friction plates In the assembly method of
(A) contacting the other end of the return spring unit with the piston and preventing the return spring unit from coming off from the piston in the axial direction;
(B) When the piston is assembled to the case, the one end of the return spring unit is brought into contact with the case and the piston is pushed toward the case to compress the return spring unit in the axial direction. Releasing the retainer for the return spring unit with respect to the piston;
A method for assembling a friction engagement device.

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