JP7192666B2 - automatic transmission - Google Patents

Description

The present invention relates to an automatic transmission mounted on a vehicle, and belongs to the technical field of automatic transmissions for vehicles.

In general, in an automatic transmission mounted on a vehicle such as an automobile, the power transmission paths of a plurality of planetary gear mechanisms are switched by selectively engaging a plurality of frictional engagement elements such as clutches and brakes to shift gears according to the operating conditions of the vehicle. A step is formed.

For example, the clutch disclosed in Patent Document 1 includes an outer member coupled to a predetermined rotating element such as a constituent member of a planetary gear mechanism or a rotating shaft, and an inner member coupled to another predetermined rotating element. have. Spline portions are provided on the inner peripheral side of the outer member and on the outer peripheral side of the inner member, and each spline portion alternately has a friction plate having an inner spline portion and a friction plate having an outer spline portion. are placed in

The brake is a multi-plate brake having a plurality of friction plates like the clutch described above, and has an outer member, an inner member, and a plurality of friction plates, and one of the outer member and the inner member is attached to the transmission case. It is fixed and non-rotatable.

For example, when a clutch transmits power, the torque input from the drive source to the automatic transmission is transmitted by contact surfaces between the spline teeth at the spline engagement portions between the inner and outer members and the friction plates. be done. Therefore, the contact surfaces of the spline engagement portions between the inner and outer members and the friction plates need to have an area corresponding to the magnitude of the torque to be transmitted.

Here, as is well known, the transmission torque capacity per friction plate of the friction engagement element is determined by the number of teeth of the friction plate, the meshing length of the spline engagement portion between the inner member and the outer member and the friction plate, and the friction plate determined by the plate thickness of

By the way, the spline engagement portion between the inner member and the outer member and the friction plate is provided with a so-called spline in order to align the center positions of the inner member and the outer member with the friction plate in order to improve the controllability of the clutch. It may fit into the formula.

In this case, for example, when the inner member is molded with a mold, it has a draft angle. Therefore, in order to ensure the accuracy of the cylindrical surface for fitting the spigot, it is necessary to machine the tooth top surface of the spline portion of the inner member. Conceivable.

JP 2016-90048 A

By the way, when the tooth top surface of the inner member is machined, an edge is formed between the tooth top surface and the tooth surface of the inner member, and sliding resistance is generated when the friction plate moves in the axial direction during fastening and releasing operations. In addition, there is a risk that the operability of the friction plates will be deteriorated, and that tooth contact of the spline engagement portion during torque transmission will be hindered.

In response to this, for example, it is conceivable to provide relief portions for avoiding contact with the edges of the inner member at the corners of the tooth roots on the friction plate side. In this case, the provision of the relief portion reduces the circumferential length of the tooth root of the friction plate, thereby shortening the circumferential dimension of the fitting surface for the spigot for centering the inner member. It will be.

Since a predetermined circumferential dimension is required to ensure the precision of the spline fitting, increasing the circumferential dimension of the spline engagement portion between the inner member and the friction plate reduces the number of teeth of the spline portion. It will be.

In order to secure the required torque capacity as the number of teeth of the spline portion decreases, it is conceivable to extend the tooth height of the spline portion and increase the plate thickness of the friction plate as described above. In this case, the radial dimension of the transmission is increased, and the increase in the plate thickness of the friction plates results in an increase in the axial dimension. That is, there is room for improvement in order to secure the spline mating surface (the circumferential length of the tooth crest) while securing the transmission torque capacity of the frictional engagement element.

Accordingly, the present invention provides an automatic transmission in which a plurality of friction plates are arranged between an inner member and an outer member. An object of the present invention is to secure the accuracy of centering between the friction plate and the inner member or the outer member by the spline engaging portion while securing the torque capacity.

In order to solve the above problems, the present invention is characterized by the following configuration.

First, the invention described in claim 1 of the present application is
An inner member having a spline portion on the outer peripheral side and an outer member having a spline portion on the inner peripheral side are alternately disposed between the inner member and the outer member and are spline-engaged with the spline portion. An automatic transmission comprising a friction engagement element having a plurality of friction plates,
Spline portions of predetermined spline engagement portions of at least one of the spline engagement portion of the inner member and the friction plate and the spline engagement portion of the outer member and the friction plate are provided at a plurality of locations in the circumferential direction. a centering spline tooth having a longer circumferential dimension than the other spline teeth and having a machined surface on the outer circumference for centering the plurality of friction plates;
The crest surfaces of the other spline teeth are formed so as to be out of contact with the bottoms of the plurality of friction plates.

Further, the invention according to claim 2 is the invention according to claim 1,
A corner portion of the tooth bottom of the friction plate corresponding to the edge between the tooth crest and the tooth surface of the centering spline tooth is provided with a relief portion recessed to be deeper than the tooth bottom. It is characterized by

Further, the invention according to claim 3 is the invention according to claim 2,
The friction engagement element has a piston that engages the plurality of friction plates,
The centering spline tooth is characterized by having an extension portion extending from the pressing surface of the piston toward the anti-friction plate side.

Further, the invention according to claim 4 is the invention according to claim 3,
The extended portion of the centering spline tooth is engaged with a notch provided in the piston even when the piston is in a released state.

Further, the invention according to claim 5 is the invention according to any one of claims 1 to 4,
The centering spline tooth includes a groove portion extending axially on the tooth crest of the centering spline tooth, and the plurality of friction plates formed obliquely with respect to the axial direction and provided at the groove bottom portion of the groove portion. and a supply port for supplying lubricating oil toward.

Further, the invention according to claim 6 is the invention according to any one of claims 1 to 5,
The friction engagement element is a starting brake that is engaged when the vehicle starts moving.

Further, the invention according to claim 7 is the invention according to claim 6,
the inner member is coupled to the transmission case,
The plurality of centering spline teeth are arranged at equal intervals in the circumferential direction, and are provided at least at the upper end position of the spline portion of the inner member.

According to the first aspect of the invention, at least one of the spline engagement portion between the inner member and the friction plate and the spline engagement portion between the outer member and the friction plate is provided with a centering spline engagement portion. By providing the spline teeth and the other spline teeth, it is possible to share the function of centering the predetermined spline engagement portion and the function of securing the transmission torque capacity.

Specifically, in the other spline teeth, by making the circumferential dimension shorter than that of the centering spline teeth, the number of teeth of a predetermined spline engaging portion is increased compared to the case where all the teeth are centered. Therefore, it is possible to secure a contact surface (area) for securing a required transmission torque capacity without extending the tooth height and the axial dimension. Furthermore, by providing the centering spline teeth at a plurality of locations, it is possible to secure the centering accuracy of the predetermined spline engaging portion.

As described above, in an automatic transmission in which a plurality of friction plates are arranged between the inner member and the outer member, the transmission torque capacity of the friction engagement element in which the plurality of friction plates are spline-engaged is secured while maintaining a compact configuration. However, the accuracy of centering by the centering spline teeth can be ensured.

According to the second aspect of the present invention, relief portions are provided at the corners of the tooth bottoms of the friction plates corresponding to the edge portions between the tooth crest and tooth flanks of the centering spline teeth. Therefore, it is possible to reduce the sliding resistance in the axial movement of the friction plates and improve the tooth contact between the tooth flanks during torque transmission.

In addition, it is easier to process the relief portion on the side of the friction plate than on the side of the inner member. Specifically, when forming relief portions in the inner member, it is necessary to process the edges of the centering spline teeth while making the tooth height of the centering spline teeth higher than the tooth height of the other spline teeth.

On the other hand, when the relief portion is formed on the friction plate side, the gap between the tooth bottom corresponding to the other spline tooth and the tooth top of the other spline tooth is defined as the tooth bottom corresponding to the centering spline tooth. It is necessary to make it smaller than the gap between the tip of the centering spline tooth and to provide a concave portion in a portion corresponding to the edge of the centering spline tooth. can.

Further, according to the third aspect of the invention, the centering spline tooth has an extending portion that extends toward the side opposite to the friction plate from the pressing surface of the piston. Falling off from the spline portion is suppressed.

Further, according to the fourth aspect of the invention, since the extending portion of the centering spline tooth and the notch portion provided in the piston are engaged with each other when the piston is in a released state, the piston can be rotated in the circumferential direction. restrained from moving. As a result, for example, in an automatic transmission having a friction engagement element having a spring that biases the piston toward the engagement direction, the piston rotates in the circumferential direction and the spring twists in the circumferential direction when the friction engagement element is engaged. can be suppressed to accurately move the piston from the release position to the zero clearance position.

By the way, for example, the supply port for supplying lubricating oil to the hub member may be inclined with respect to the radial direction. In this case, since the direction of the supply port is not parallel to the friction plate, the overall tooth height of the spline teeth is shortened in order to suppress axial movement of the friction plate when lubricating oil is supplied. It is conceivable to suppress the axial movement of the friction plate by securing the distance between the friction plate and the lubrication hole. Capacity may be sacrificed.

According to the fifth aspect of the invention, a predetermined gap is secured between the friction plate and the lubrication hole by providing the groove portion in the centering spline tooth having a large circumferential dimension. As a result, unintended axial movement of the friction plates can be suppressed without sacrificing the tooth flank area of the spline teeth.

Further, according to the sixth aspect of the invention, the starting brake needs to transmit a large torque compared to other friction engagement elements. Suppressing the decrease has a more pronounced effect.

Further, according to the seventh aspect of the invention, the friction plate spline-engaged with the hub member is normally smoothed downward by its own weight. If the teeth are not arranged in the same direction, the backlash tends to be greater than when centering is performed on all the teeth. On the other hand, since the centering spline teeth are arranged on the upper side of the hub member, even if the looseness is reduced in the downward direction due to the weight of the hub member, it will not be as strong as when the centering spline teeth are not arranged on the upper side. As a result, the backlash of the friction plate with respect to the hub member can be reduced.

1 is a skeleton diagram of an automatic transmission according to an embodiment of the invention; FIG. 4 is an engagement table of frictional engagement elements of the automatic transmission; 2 is a cross-sectional view of a brake of an automatic transmission and its surroundings; FIG. 4 is another cross-sectional view of the brake of the automatic transmission and its surroundings; FIG. It is a perspective view which shows a hub member. FIG. 4 is a front view showing main parts of a hub member and friction plates; FIG. 4 is a front view showing main parts of a hub member and a piston of the brake; FIG. 4 is an explanatory view of contact surfaces of a hub member of a brake and friction plates during torque transmission;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a skeleton diagram of an automatic transmission according to an embodiment of the invention. The automatic transmission 10 is connected to a drive source such as an engine without interposing a fluid transmission device such as a torque converter. The automatic transmission 10 is provided in a transmission case 11 with an input shaft 12 connected to a drive source and arranged on the drive source side (left side in the drawing), and an input shaft 12 arranged on the opposite side of the drive source (right side in the drawing). and an output shaft 13 . The automatic transmission 10 is of a vertical type, such as for a front-engine/rear-drive vehicle, in which an input shaft 12 and an output shaft 13 are arranged on the same axis.

First, second, third and fourth planetary gear sets (hereinafter simply referred to as "first, second, third and fourth gear sets") are arranged on the axial center of the input shaft 12 and the output shaft 13 from the drive source side. PG1, PG2, PG3, and PG4 are provided.

In the transmission case 11, the first clutch CL1 is arranged on the drive source side of the first gear set PG1, the second clutch CL2 is arranged on the drive source side of the first clutch CL1, and the drive source of the second clutch CL2 is arranged. A third clutch CL3 is arranged on the side. A first brake BR1 is arranged on the drive source side of the third clutch CL3, and a second brake BR2 is arranged on the drive source side of the third gear set PG3 and on the opposite side to the drive source of the second gear set PG2.

The first, second, third, and fourth gear sets PG1, PG2, PG3, and PG4 are all single pinion types in which pinions supported by carriers directly mesh with the sun gear and ring gear. The first, second, third, and fourth gear sets PG1, PG2, PG3, and PG4 respectively include sun gears S1, S2, S3, and S4, ring gears R1, R2, R3, and R4, and carriers C1 and C2 as rotating elements. , C3 and C4.

The first gear set PG1 is of a double sun gear type in which the sun gear S1 is divided into two in the axial direction. The sun gear S1 has a first sun gear S1a arranged on the drive source side and a second sun gear S1b arranged on the side opposite to the drive source. The first and second sun gears S1a, S1b have the same number of teeth and mesh with the same pinion supported by the carrier C1. As a result, the first and second sun gears S1a and S1b always rotate in the same direction.

In the automatic transmission 10, the sun gear S1 of the first gear set PG1, specifically the second sun gear S1b and the sun gear S4 of the fourth gear set PG4 are always connected, and the ring gear R1 of the first gear set PG1 and the sun gear of the second gear set PG2 are connected. S2 is always connected, the carrier C2 of the second gear set PG2 and the carrier C4 of the fourth gear set PG4 are always connected, and the carrier C3 of the third gear set PG3 and the ring gear R4 of the fourth gear set PG4 are always connected. .

The input shaft 12 is always connected to the carrier C1 of the first gear set PG1 through between the first sun gear S1a and the second sun gear S1b, and the output shaft 13 is always connected to the carrier C4 of the fourth gear set PG4.

The first clutch CL1 is disposed between the input shaft 12 and the carrier C1 of the first gear set PG1 and the sun gear S3 of the third gear set PG3 to connect and disconnect them. The third clutch CL3 is disposed between the ring gear R1 of the first gear set PG1, the sun gear S2 of the second gear set PG2, and the sun gear S3 of the third gear set PG3 to connect and disconnect them. It is arranged between the ring gear R2 of PG2 and the sun gear S3 of the third gear set PG3 to connect and disconnect them.

The first brake BR1 is disposed between the transmission case 11 and the sun gear S1 of the first gear set PG1, specifically the first sun gear S1a, to connect and disconnect them. is arranged between the transmission case 11 and the ring gear R3 of the third gear set PG3 to connect and disconnect them.

With the above configuration, the automatic transmission 10 can achieve D 1st to 8th speed in the range and reverse speed in the R range are formed.

In the automatic transmission 10, the second brake BR2, which is engaged in the 1st speed stage at the time of starting, is slip-controlled, and the second brake BR2 corresponds to the friction engagement element of the automatic transmission according to the present invention. The brake BR2 will be described below.

As shown in FIG. 3, the brake BR2 is housed in a substantially cylindrical transmission case 11 and is connected to the sun gear S3 of the third gear set PG3 to provide first, second and third clutches CL1 and CL2. , CL3 are arranged on the outer peripheral side of the power transmission member 14 in which one of the pair of inner and outer rotary members is integrated.

The power transmission member 14 is arranged on the outer peripheral side of the power transmission member 15 connecting the carrier C2 of the second gear set PG2 and the carrier C4 of the fourth gear set PG4. Specifically, it is arranged on the outer peripheral side of the power transmission member 16 that connects the second sun gear S1b and the sun gear S4 of the fourth gear set PG4.

The brake BR2 includes a hub member 20 coupled to the transmission case 11, a drum member 60 arranged on the side opposite to the driving source of the hub member 20 and coupled to the ring gear R3 of the third gear set PG3, the hub member 20 and the drum. It has a plurality of friction plates 70 arranged axially side by side with the member 60, and a piston 80 arranged on the side opposite to the driving source of the plurality of friction plates 70 and fastening the plurality of friction plates 70. .

The brake BR<b>2 has a hydraulic chamber 90 to which hydraulic oil for urging the piston 80 is supplied radially inward of the hub member 20 . The hydraulic chamber 90 includes a fastening hydraulic chamber 91 supplied with hydraulic fluid for fastening that biases the piston 80 in the fastening direction, and a hydraulic pressure chamber for release supplied with hydraulic fluid for disengagement that biases the piston 80 in the releasing direction. 92.

As shown in FIG. 3, the brake BR2 also includes a spring 101 that acts as a biasing member that biases the piston 80 radially inwardly of the hub member 20 and that biases the piston 80 in the fastening direction.

As shown in FIG. 3 , the brake BR2 includes a hub support member 31 that forms a partition provided inside the transmission case 11 and supports the hub member 20 . The hub member 20 is arranged on the piston side (opposite side of the drive source) of the hub support member 31 , and is spline-engaged with a plurality of friction plates 70 and the transmission case 11 .

The hub support member 31 is formed extending radially inward from the hub member 20 . A first hydraulic chamber forming member 41 is connected to the hub support member 31 on the side opposite to the drive source and constitutes a hydraulic chamber. A second hydraulic chamber forming member 51 is coupled to the drive source side.

The hub member 20 includes a vertical wall portion 22 extending in a direction perpendicular to the axial direction of the transmission case 11 and formed in a substantially disk shape, and a radially inner side of the vertical wall portion 22 on the side opposite to the drive source from the vertical wall portion 22 . and a cylindrical portion 23 extending in a substantially cylindrical shape.

The hub member 20 has a spline portion 24 in which splines are formed on the outer peripheral surface of the vertical wall portion 22 , and the spline portion 24 is spline-engaged with the spline portion 11 a in which the splines are formed on the inner peripheral surface of the transmission case 11 . and coupled to the transmission case 11 .

The cylindrical portion 23 of the hub member 20 has a spline portion 25 formed with splines on its outer peripheral surface.

The hub support member 31 includes a vertical wall portion 32 extending in a direction orthogonal to the axial direction of the transmission case 11 and formed in a substantially disc shape. As shown in FIG. 4 , the vertical wall portion 32 of the hub support member 31 is formed with a lubricating supply oil passage L1 for supplying lubricating operating oil to the friction plates 70 .

The outer peripheral surface of the vertical wall portion 32 of the hub support member 31 is fitted to the inner peripheral surface 11 b of the transmission case 11 on the drive source side of the spline portion 24 of the hub member 20 . The hub support member 31 is secured to the transmission case 11 by a snap ring 17 to prevent it from coming off toward the drive source, and is also fixed to the transmission case 11 using a detent pin 18 . Alternatively, the hub support member 31 may be press-fitted and fixed to the inner peripheral surface 11b of the transmission case 11 to be coupled to the transmission case 11 .

Below the transmission case 11, as shown in FIG. 4, a valve body 5 for supplying working oil to the hydraulic chamber 90 of the brake BR2, the friction plates 70, and the like is arranged. The valve body 5 is housed in an oil pan (not shown) attached below the transmission case 11 and fixed to the transmission case 11 . The hub support member 31 has a valve body connecting portion 34 for connecting to the valve body 5, and the lubricating supply oil passage L1 is connected to the valve body 5 through a case opening 11c formed in the transmission case 11. is formed as

The vertical wall portion 32 of the hub support member 31 is formed with a fastening supply oil passage (not shown) for supplying fastening hydraulic fluid to the fastening hydraulic chamber 91 , and a releasing hydraulic chamber 92 is provided with a releasing hydraulic fluid. A release supply oil passage (not shown) for supplying oil is formed.

The lubricating supply oil passage L1, the release supply oil passage, and the fastening supply oil passage are arranged side by side in the circumferential direction on the lower side of the transmission case 11. The supply oil passage for the valve body 5 and the supply oil passage for the fastening are formed so as to be connected to the valve body 5 respectively.

As shown in FIG. 3, the vertical wall portion 32 of the hub support member 31 is formed with a stepped portion 32a recessed toward the drive source on the side opposite to the drive source. The stepped portion 32 a of the hub support member 31 is engaged with the inner peripheral side of the vertical wall portion 22 of the hub member 20 when the vertical wall portion 22 of the hub member 20 abuts against the vertical wall portion 32 of the hub support member 31 . is formed as

The vertical wall portion 32 of the hub support member 31 is provided with an extension portion 32b that extends radially inward of the hub member 20 . The vertical wall portion 32 (extension portion 32b) of the hub support member 31 is formed with a plurality of boss portions 35 extending in a substantially cylindrical shape toward the side opposite to the drive source. The plurality of boss portions 35 are, for example, distributed in the circumferential direction, and screw holes 35a are formed in the respective boss portions 35 on the side opposite to the drive source. By screwing a fastening bolt B1 into the screw hole 35a of the boss portion 35 from the side of the second hydraulic chamber constituting member 51 opposite to the driving source, the first hydraulic chamber constituting member 41 and the second A hydraulic chamber forming member 51 is coupled.

As shown in FIG. 3 , the first hydraulic chamber forming member 41 includes a vertical wall portion 42 extending in a direction perpendicular to the axial direction of the transmission case 11 and formed in a substantially disc shape, and a radial direction of the vertical wall portion 42 . A first cylindrical portion 43 substantially cylindrically extending from the outside toward the side opposite to the drive source, and a second cylindrical portion 44 substantially cylindrically extending from the radially inner side of the vertical wall portion 42 toward the side opposite to the drive source. The portion 43 and the second cylindrical portion 44 are formed to have substantially equal axial lengths.

The drive source side surface of the vertical wall portion 42 of the first hydraulic chamber component member 41 abuts against the drive source side surface of the extended portion 32b of the hub support member 31 at an axial mating surface F. As shown in FIG.

The first cylindrical portion 43 of the first hydraulic chamber component 41 is provided radially inside the cylindrical portion 23 of the hub member 20 . The first cylindrical portion 43 of the first hydraulic chamber component 41 has a flange portion 43a extending radially outward so as to contact the inner peripheral surface of the cylindrical portion 23 of the hub member 20 on the side opposite to the drive source. is provided so as to form a lubricating supply oil passage L1 between itself and the cylindrical portion 23 of the .

The second cylindrical portion 44 of the first hydraulic chamber component 41 has an outer peripheral surface 44a on the side of the driving source and an outer peripheral surface 44b on the side opposite to the driving source. The radial dimension is formed to be smaller than that of the outer peripheral surface 44a on the drive source side so as to form 92 .

As shown in FIG. 3, the second cylindrical portion 44 of the first hydraulic chamber forming member 41 is also recessed in a substantially rectangular shape from the drive source side to the opposite drive source side to support a plurality of boss portions 35 of the hub support member 31. A plurality of boss accommodation portions 45 for accommodating the respective boss portions 45 and bolt insertion holes 44c for inserting the fastening bolts B1 are formed.

The second hydraulic chamber component 51 extends in a direction orthogonal to the axial direction of the transmission case 11 and is formed in a substantially disc shape, and is arranged on the opposite side of the first hydraulic chamber component 41 to the drive source. A bolt insertion hole 52 through which the fastening bolt B1 is inserted is formed inside the second hydraulic chamber component 51 in the radial direction.

As described above, the fastening bolt B1 is supported by the hub through the bolt insertion hole 52 of the second hydraulic chamber constituent member 51 and the bolt insertion hole 44c of the first hydraulic chamber constituent member 41 from the opposite side of the driving source of the second hydraulic chamber constituent member 51. By screwing it into the screw hole 35a of the member 31, the first hydraulic chamber forming member 41 is coupled to the hub supporting member 31 on the side opposite to the drive source, and the second hydraulic chamber forming member 41 is coupled to the first hydraulic chamber forming member 41 on the side opposite to the drive source. A hydraulic chamber forming member 51 is coupled.

The second hydraulic chamber constituent member 51 is formed to extend radially outward from the second cylindrical portion 44 of the first hydraulic chamber constituent member 41 , and the outer peripheral surface of the second hydraulic chamber constituent member 51 extends through a seal member 53 . It is fitted on the piston 80 .

A facing surface (drive source side surface) 54 of the second hydraulic chamber forming member 51 facing a hydraulic chamber forming portion 82 of a later-described piston 80 is provided with a stepped portion recessed toward the side opposite to the drive source. A shim member 55 is arranged on the facing surface 54 of the second hydraulic chamber constituting member 51 facing the piston 80, and the radially inner end of the shim member 55 is arranged in a stepped portion.

A plurality of springs 101 and a plurality of stopper portions 86 of the piston 80 are brought into contact with the shim member 55 . The shim member 55 restricts the piston 80 to a predetermined release position when the stopper portion 86 of the piston 80 abuts the side surface of the shim member 55 on the drive source side. Thus, the shim member 55 for adjusting the release position of the piston 80 is attached to the second hydraulic chamber component 51 .

The hub support member 31, the hub member 20, the first hydraulic chamber constituent member 41, and the second hydraulic chamber constituent member 51 are each made of the same aluminum-based material.

The drum member 60 includes a cylindrical portion 61 that is arranged to face the outer peripheral side of the cylindrical portion 23 of the hub member 20 and extends in the axial direction in a substantially cylindrical shape, and a transmission case 11 extending radially inward from the side of the cylindrical portion 61 opposite to the drive source. and a vertical wall portion 62 extending in a direction orthogonal to the axial direction of and formed in a substantially disc shape.

A vertical wall portion 62 of the drum member 60 is coupled to a ring gear R3 as a rotating member. A cylindrical portion 61 of the drum member 60 has a spline portion 61a formed with splines on the inner peripheral surface thereof, and a rotation-side friction plate 72 constituting the friction plate 70 is spline-engaged with the spline portion 61a. The fixed-side friction plates 71 and the rotation-side friction plates 72 are arranged alternately in the axial direction.

The piston 80 is arranged between the hub member 20 and the drum member 60 , specifically between the cylindrical portion 33 of the hub member 20 and the cylindrical portion 61 of the drum member 60 . It is slidably fitted to the outer peripheral surface of the second cylindrical portion 44 . The piston 80 is prevented from coming off to the side opposite to the drive source by the second hydraulic chamber component 51 .

As shown in FIG. 4, the piston 80 has a pressing portion 81 provided on the outer peripheral side for pressing the friction plate 70, and a hydraulic chamber forming portion provided on the inner peripheral side for forming the hydraulic chamber 90. 82, a connecting portion 83 that connects the pressing portion 81 and the hydraulic chamber forming portion 82, and a plurality of stopper portions 86...86 that regulate the release position of the piston 80.

The pressing portion 81 of the piston 80 is arranged on the side opposite to the drive source of the friction plate 70, the hydraulic chamber forming portion 82 is arranged radially inside the hub member 20, and the connecting portion 83 forms the hydraulic chamber together with the pressing portion 81. It extends radially inward of the friction plate 70 from the opposite side of the friction plate 70 to the drive source so as to be connected to the portion 82 .

A hydraulic chamber forming portion 82 of the piston 80 is formed by a surface 84 on the opposite side of the drive source (surface on the side of the second hydraulic chamber forming member 51 ) extending radially inside the hub member 20 in the radial direction. make up the department. A stepped portion 85 recessed from the inner diameter side toward the outer diameter side is provided on the inner peripheral portion of the hydraulic chamber forming portion 82 , and the stepped portion 85 and the inner cylindrical portion 44 of the first hydraulic chamber forming member 41 are formed. The release hydraulic chamber 92 is partitioned by .

The piston 80 extends radially inward from the side of the friction plate 70 opposite to the drive source and is fitted to the outer peripheral surface of the second hydraulic chamber component 51 . It extends inward and is fitted to the outer peripheral surfaces 44 a and 44 b of the second cylindrical portion 44 of the first hydraulic chamber component 41 . A sealing member 87 for sealing between the hydraulic chamber forming portion 82 and the first hydraulic chamber forming member 41 is attached to the radially inner end of the hydraulic chamber forming portion 82 of the piston 80 on the side opposite to the drive source. . A sealing member 88 for sealing between the hydraulic chamber forming portion 82 and the first hydraulic chamber forming member 41 is attached to the radially inner end of the hydraulic chamber forming portion 82 of the piston 80 on the drive source side.

Thus, the fastening hydraulic chamber 91 is a space defined by the surface 84 of the hydraulic chamber forming portion 82 of the piston 80 on the side opposite to the drive source, the first hydraulic chamber forming member 41 and the second hydraulic chamber forming member 51. formed by The release hydraulic chamber 92 is formed by a space partitioned by the stepped portion 85 of the hydraulic chamber forming portion 82 of the piston 80 and the first hydraulic chamber forming member 41 .

As shown in FIG. 3 , the plurality of stopper portions 86 are arranged inside the fastening hydraulic chamber 91 . Each stopper portion 86 is formed in a cylindrical shape. The stopper portion 86 is formed so as to extend from the surface of the hydraulic chamber forming portion 82 of the piston 80 on the opposite side of the drive source to the surface 54 of the second hydraulic chamber forming member 51 facing the piston 80 . Each stopper portion 86 is configured to restrict the released position of the piston 80 by contacting the shim member 55 of the second hydraulic chamber forming member 51 at the tip of the stopper portion 86 when the piston 80 is in the released state. ing.

As shown in FIG. 3, the spring 101 is arranged in the fastening hydraulic chamber 91 . A hydraulic chamber forming portion 82 of the piston 80 forming the fastening hydraulic chamber 91 is configured such that a surface 84 on the side opposite to the drive source receives the biasing force of the spring 101 . The end of the spring 101 on the side opposite to the piston is arranged so as to come into contact with the shim member 55 arranged on the surface 54 of the second hydraulic chamber forming member 51 facing the piston 80 . The spring 101 , the fastening hydraulic chamber 91 and the releasing hydraulic chamber 92 are arranged radially inside the hub member 20 so as to overlap each other in the radial direction.

A plurality of springs 101 made of coil springs extending in the axial direction are held at their ends on the drive source side by a ring-shaped holding plate 102 . The holding plate 102 is provided with a plurality of spring guide portions 103 protruding cylindrically toward the side opposite to the drive source and to which a plurality of springs 101 are respectively mounted. are placed in different positions. Each stopper portion 86 of the piston 80 is inserted into each spring 101 from the drive source side.

By adjusting the thickness of the shim member 55, the piston 80 can maintain the clearance between the pressing surface 81a of the pressing portion 81 of the piston 80 and the friction plate 70 at a predetermined value. there is At this time, since the stopper portion 86 and the spring 101 are provided in parallel between the piston 80 and the shim member 55, changing the thickness of the shim member 55 affects the compressed state of the spring 101 in the released state. Giving can be suppressed.

The spring 101 is supported on the side opposite to the drive source of the hydraulic chamber forming portion 82 of the piston 80 via the holding plate 102 , and the side opposite to the drive source of the spring 101 is connected to the drive source side of the second hydraulic chamber forming member 51 as a shim member. 55. The spring 101 is set so that the piston 80 is at the zero clearance position when the spring 101 is at its free length.

In this manner, the spring 101 applies a biasing force in the fastening direction to the piston 80 from the release position to the zero clearance position. When the fastening hydraulic pressure is supplied to the fastening hydraulic chamber 91 when the piston 80 is at the zero clearance position, the piston 80 presses the plurality of friction plates 70 so that the plurality of friction plates 70 move toward the vertical wall portion of the hub member 20 . 22 and the piston 80, and becomes a fastening state in which relative rotation is disabled.

On the other hand, when the engagement hydraulic pressure is discharged from the engagement hydraulic chamber 91 and the release hydraulic pressure is supplied to the release hydraulic chamber 92 when the piston 80 is in the engagement position, the piston 80 is urged and moved in the release direction. , the piston 80 is moved to the zero clearance position. The piston 80 is further biased in the release direction against the spring 101 and moved to the release position.

Next, a supply oil passage for supplying hydraulic oil to the brake BR2 will be described.
A lubricating supply oil passage L<b>1 that supplies lubricating hydraulic oil to the friction plate 70 is formed in the hub supporting member 31 , the hub member 20 and the first hydraulic chamber forming member 41 . An engagement supply oil passage (not shown) L2 for supplying engagement hydraulic oil to the engagement hydraulic chamber 91 is formed in the hub support member 31, the first hydraulic chamber constituent member 41, and the second hydraulic chamber constituent member 51. there is A release supply oil passage (not shown) L3 for supplying release hydraulic oil to the release hydraulic chamber 92 is formed in the hub support member 31 and the first hydraulic chamber constituent member 41 .

As shown in FIGS. 3 and 4, the lubricating supply oil passage L1 includes a radial oil passage 131 provided in the vertical wall portion 32 of the hub support member 31 and extending in the radial direction, and a radial oil passage 131 of the hub support member 31. A circumferential oil passage 132 connected to the passage 131 and annularly provided in the circumferential direction between the cylindrical portion 23 of the hub member 20 and the cylindrical portion 43 of the first hydraulic chamber constituting member 41; A communication oil passage 133 that communicates with the directional oil passage 132 and extends in the axial direction; and a supply port 134 that opens in the surface and supplies lubricating hydraulic oil to the friction plate 70 .

As shown in FIG. 3 , a plurality of supply ports 134 are provided side by side in the axial direction of the cylindrical portion 23 of the hub member 20 and are provided in a plurality of circumferentially spaced apart relation to the cylindrical portion 23 of the hub member 20 . The supply port 134 is provided so as to open to the tooth tip of each centering spline tooth 26 described later of the spline portion 25 of the cylindrical portion 23 of the hub member 20 .

A groove portion 26d extending in the axial direction is formed at the center position in the circumferential direction on the tooth top surface 26a of the centering spline tooth 26 provided with the supply port 134. The supply port 134 is formed on the groove bottom portion 26e of the groove portion 26d. is formed in As a result, the distance between each friction plate 70 engaged with the spline portion 25 and the outlet of the supply port 134 is increased compared to the case where the groove portion 26d is not provided on the tooth crest 26a of the centering spline tooth 26. be done.

As described above, the hub support member 31 is formed such that the lubricating supply oil passage L1 is connected to the valve body 5 . A radial oil passage 131 of the hub support member 31 is provided in the vertical wall portion 32 of the hub support member 31 , opens to the lower surface of the valve body connecting portion 34 , and is connected to the valve body 5 . The valve body 5 can supply lubricating hydraulic oil to the plurality of friction plates 70 through lubricating supply oil passages L1.

As shown in FIG. 5, the spline portion 25 is formed with centering spline teeth 26 having machined surfaces 26A for centering the plurality of friction plates 70 on the outer circumference, and having a shorter circumferential dimension than the centering spline teeth 26. and other spline teeth 27 for spline engagement with a plurality of friction plates 70 on the outer periphery.

The centering spline teeth 26 have a predetermined axial length to spline the plurality of friction plates 70 even in the released state, and the other spline teeth 27 have a longer axial length than the centering spline teeth 26. formed short.

The centering spline teeth 26 are arranged at three locations at approximately equal intervals in the circumferential direction. The three centering spline teeth 26 are provided at least at the upper end position of the spline portion 25 of the hub member 20 .

As shown in FIG. 6, the tooth bottoms 70a of the plurality of friction plates 70 engaged with the spline portion 25 of the hub member 20 and the tooth crests 27a of the other spline teeth 27 are kept in a non-contact state. is formed in Specifically, the tooth bottom 70 a of each friction plate 70 corresponding to the other spline tooth 27 is formed deeper than the tooth bottom 70 b of each friction plate 70 corresponding to the centering spline tooth 26 .

Each friction plate 70 has a gap g1 between the tooth crest 26a of the centering spline tooth 26 of the hub member 20 and the opposing tooth bottom 70b, and the other tooth of the spline tooth 27 of the hub member 20 is larger than the gap g1. By providing a large gap g2 between the tip surface 27a and the tooth bottom 70a facing the top surface 27a, the tooth top surface 27a of the other spline tooth 27 and the tooth bottom 70a of the friction plate 70 are kept in a non-contact state. .

A corner portion 70c of the tooth bottom 70b of each friction plate 70 corresponding to the edge 26c between the tooth top surface 26a and the tooth surface 26b of the centering spline tooth 26 of the hub member 20 is provided with a groove deeper than the tooth bottom 70b. is provided with an escape portion 70d.

As shown in FIG. 3, the centering spline tooth 26 has an extension portion 26B that extends toward the anti-friction plate side from the pressing surface 81a of the pressing portion 81 of the piston 80 on the friction plate 70 side. The extending portion 26B of the piston 80 is engaged with a notch portion 83b provided in the connecting portion 83 of the piston 80. As shown in FIG.

Specifically, the coupling portion 83 of the piston 80 is formed with a hub member notch portion 83 b corresponding to the centering spline tooth 26 of the hub member 20 . The opposite side of the centering spline teeth 26 of the cylindrical portion 23 of the hub member 20 is fitted into the hub member notch 83b of the piston 80, and the hub member 20 and the piston 80 overlap in the axial direction. are placed.

FIG. 7 is a front view showing main parts of the hub member 20 and the piston 80 of the brake BR2. As shown in FIG. 7 , the hub member notch 83 b is formed corresponding to the centering spline teeth 26 of the hub member 20 . The hub member notch 83b is cut out larger than the cross-sectional shape of the centering spline tooth 26 of the hub member 20, and is arranged along both side surfaces (tooth surfaces) 26b of the centering spline tooth 26. 83c. In the piston 80, three hub member cutouts 83b are formed at substantially equal intervals in the circumferential direction corresponding to a plurality of, specifically, three centering spline teeth 26 of the hub member 20. As shown in FIG.

In the hub member 20, when the piston 80 rotates in the circumferential direction, the side surface 83c of the hub member notch 83b contacts the side surface (tooth surface) 26b of the centering spline tooth 26 of the hub member 20 so that the piston 80 is in place. Rotation of more than a fixed amount, for example, more than a predetermined amount at which the rotation angle of the piston 80 is 1 degree, is restricted.

The side surface 83c of the hub member notch 83b functions as a restricting portion that is arranged along the side surface (tooth surface) 26b of the centering spline tooth 26 of the hub member 20. functions as a piston rotation restricting member that restricts the piston 80 from rotating more than a predetermined amount in the circumferential direction.

Here, a contact surface (area) S that contributes to torque transmission at the hub member 20 of the brake BR2 and the spline engagement portion 20A of the friction plate 70 will be described with reference to FIG.

The torque input from the drive source to the automatic transmission is transmitted by contact surfaces between the spline teeth at the spline engagement portions between the hub member and the drum member and the friction plates when the friction engagement elements transmit power. be. Therefore, the contact surfaces of the spline engagement portions between the hub member and the drum member and the friction plates need to have an area corresponding to the magnitude of the torque to be transmitted.

As is well known, the transmission torque capacity per friction plate of the friction engagement element is determined by the number of teeth n of the friction plate, the meshing length h of the spline engagement portion between the inner member and the outer member and the friction plate, and the friction plate It is determined by the plate thickness t of

If the engagement length h of the spline engagement portion is increased, the radial dimension of the transmission may be increased, and if the thickness t of the friction plate is increased, the axial dimension of the transmission is increased. There is a risk. Therefore, in the spline portion of the frictional engagement element, it is important to secure the number of teeth n in order to secure the required transmission torque capacity.

On the other hand, in the automatic transmission according to the present invention, the spline engagement portion 21 of the hub member 20 and the friction plate 70 is provided with the centering spline teeth 26 and the other spline teeth 27 to achieve the spline engagement. The centering function of the portion 21 and the function of securing the transmission torque capacity can be shared.

Specifically, in the other spline teeth 27, by making the circumferential dimension shorter than the centering spline teeth 26, the spline engagement between the hub member 20 and the friction plate 70 is reduced compared to the case where all the teeth are centered. Since the number of teeth of the joining portion 21 can be increased, the contact surface (area) S for the required transmission torque capacity can be secured without extending the tooth height and the axial dimension. Furthermore, by providing the centering spline teeth 26 at three locations in the circumferential direction, the centering accuracy of the spline engagement portion 21 between the hub member 20 and the friction plate 70 can be ensured.

As a result, in the automatic transmission 10 in which the plurality of friction plates 70 are arranged between the hub member 20 and the drum member 60, the transmission of the brake BR2 in which the plurality of friction plates 70 are spline-engaged while being compactly configured. It is possible to secure centering accuracy by the centering spline teeth 26 while securing torque capacity.

In addition, since a relief portion 70d is provided at a corner portion 70c of the tooth bottom 70b of the friction plate 70 corresponding to the edge 26c between the tooth crest 26a and the tooth surface 26b of the centering spline tooth 26, friction It is possible to reduce the sliding resistance in the axial movement of the plate 70 and improve the tooth contact between the tooth flanks during torque transmission.

Further, the friction plate 70 is formed so that the tooth bottom 70a corresponding to the other spline teeth 27 is deeper than the tooth bottom 70b corresponding to the centering spline tooth 26. Machining is easier than in the case where the centering spline tooth 26 is formed to have a higher tooth height than the other spline teeth.

Specifically, for example, when providing a non-contact structure between the tooth bottom of the friction plate and the tooth tip of the spline tooth on the friction plate side on the hub member side formed by aluminum die casting, etc., the spline tooth is machined. Sometimes it is necessary to make the centering spline tooth 26 taller than the other spline teeth. On the other hand, when providing a non-contact structure between the tooth bottom of the friction plate and the tooth tip of the spline tooth on the friction plate side, it can be formed by press working or the like.

Since the centering spline tooth 26 of the hub member 20 has an extension portion 26B that extends toward the anti-friction plate side from the pressing surface 81a of the piston 80, the friction plate falls off the spline portion even when the piston is released. is suppressed.

The notch portion 83b provided in the connecting portion 83 of the piston 80 arranged axially adjacent to the friction plate 70 and the extending portion 26B of the centering spline tooth 26 overlap axially in the released state of the piston. , the axial dimension of the brake BR2 can be reduced.

The extended portion 26B of the centering spline tooth 26 is engaged with the notch portion 83b of the piston 80, and the notch portion 83b of the piston 80 is formed along the shape of the outer peripheral portion of the centering spline tooth 26. Therefore, the rotation of the piston 80 in the circumferential direction is suppressed.

As a result, in the automatic transmission 10 having the frictional engagement element having the spring 101 that biases the piston 80 toward the engagement direction, the piston 80 rotates in the circumferential direction when the frictional engagement element BR2 is engaged, and the spring 101 moves in the circumferential direction. It is possible to precisely move the piston 80 from the release position to the zero clearance position by suppressing the twisting.

For example, the supply port 134 for supplying lubricating oil to the hub member 20 may be inclined with respect to the radial direction. In this case, since the direction of the supply port 134 is not parallel to the friction plate 70, the overall tooth height of the spline teeth is shortened in order to suppress the axial movement of the friction plate 70 when supplying the lubricating oil. It is conceivable to suppress the axial movement of the friction plate by securing the distance between the friction plate and the lubrication hole. and the torque capacity may be sacrificed.

In contrast, in the present embodiment, a predetermined gap is secured between the friction plate 70 and the lubrication hole 134 by providing the groove portion 26d in the centering spline tooth 26 having a large circumferential dimension in the spline portion 25. ing. As a result, unintended axial movement of the friction plates can be suppressed without sacrificing the tooth surface area of the spline portion 25 .

Since the second brake BR2 for starting needs to transmit a large torque compared to other friction engagement elements, it is more conspicuous to suppress the decrease in the number of teeth of the spline portion while centering the friction plate. effect is obtained.

Normally, the friction plate 70 that is spline-engaged with the hub member 20 is freed from looseness in the downward direction by its own weight. Compared to the case where centering is performed with

On the other hand, in the present embodiment, the centering spline teeth 26 are arranged at the upper end position of the hub member 20, so that even if the looseness is reduced downward by its own weight, the centering spline teeth 26 will not move. The rattling of the friction plate 70 with respect to the hub member 20 can be reduced as compared with the case where the is not arranged at the upper end position.

By providing the three centering spline teeth 26, it is possible to ensure both centering accuracy and torque capacity.

The present invention is not limited to the illustrated embodiments, and various improvements and design changes are possible without departing from the gist of the invention.

For example, in the present embodiment, a hub member having three centering spline teeth has been described. Three or more teeth may be provided.

Further, for example, in this embodiment, the hub member provided with the centering spline teeth has been described, but the centering spline teeth may also be received by the drum member, in which case the transmission torque capacity of the drum member is ensured. At the same time, it is possible to improve the centering accuracy between the drum member and the friction plate.

As described above, according to the present invention, in an automatic transmission in which a plurality of friction plates are arranged between an inner member and an outer member, splines between the inner member, the outer member, and the friction plates can be made compact. Since it is possible to secure the accuracy of centering between the friction plate and the inner member or the outer member by the spline engagement portion while securing the transmission torque capacity in the engagement portion, this kind of automatic transmission or this There is a possibility that it will be suitably used in the manufacturing technical field of the vehicle in which it is mounted.

10 automatic transmission 11 transmission case 20 hub member (inner member)
21 spline engaging portion 25 spline portion 26A machined surface 26B extending portion 26 centering spline tooth 26a centering spline tooth crest surface 26b centering spline tooth tooth surface 26c edge 26d groove portion 26e groove bottom portion 27 other spline tooth 27a and others The tooth crest 60 of the spline tooth of the drum member (outer member)
61a spline portion 70 a plurality of friction plates 70a friction plate tooth bottom 70c friction plate tooth bottom corner 70d relief portion 80 piston 81a pressing surface 83b notch 134 supply port BR2 starting brake (friction engagement element)

Claims (7)

An inner member having a spline portion on the outer peripheral side and an outer member having a spline portion on the inner peripheral side are alternately disposed between the inner member and the outer member and are spline-engaged with the spline portion. An automatic transmission comprising a friction engagement element having a plurality of friction plates,
Spline portions of predetermined spline engagement portions of at least one of the spline engagement portion of the inner member and the friction plate and the spline engagement portion of the outer member and the friction plate are provided at a plurality of locations in the circumferential direction. a centering spline tooth having a longer circumferential dimension than the other spline teeth and having a machined surface on the outer circumference for centering the plurality of friction plates;
The automatic transmission, wherein the crest surfaces of the other spline teeth are formed so as to be in a non-contact state with the bottoms of the plurality of friction plates. A corner portion of the tooth bottom of the friction plate corresponding to the edge between the tooth crest and the tooth surface of the centering spline tooth is provided with a relief portion recessed to be deeper than the tooth bottom. 2. The automatic transmission according to claim 1, wherein the automatic transmission is . The friction engagement element has a piston that engages the plurality of friction plates,
3. The automatic transmission according to claim 2, wherein the centering spline tooth has an extension portion extending toward the side opposite to the friction plate from the pressing surface of the piston. 4. The automatic transmission according to claim 3, wherein the extended portion of the centering spline tooth is engaged with a notch provided in the piston. The centering spline tooth includes a groove portion extending axially on the tooth crest of the centering spline tooth, and the plurality of friction plates formed obliquely with respect to the axial direction and provided at the groove bottom portion of the groove portion. 5. The automatic transmission according to any one of claims 1 to 4, further comprising a supply port for supplying lubricating oil to the . 6. The automatic transmission according to any one of claims 1 to 5, wherein the friction engagement element is a starting brake that is engaged when the vehicle starts moving. the inner member is coupled to the transmission case,
7. The automatic transmission according to claim 6, wherein the plurality of centering spline teeth are circumferentially arranged at regular intervals and provided at least at an upper end position of the spline portion of the inner member.

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