JP2023027588A - automatic transmission - Google Patents

Abstract

To achieve both curbing of a manufacturing cost and improvement in shift responsiveness.SOLUTION: An automatic transmission 1 comprises: a first clutch CL1 and a second clutch CL2 aligned in a shaft direction; a third clutch CL3 arranged on one side of the first and second clutches CL1 and CL2 in the shaft direction; an intermediary planetary gear set (PG1 and PG2) arranged between a set of the first and second clutches CL1 and CL2 and third clutches CL3; an outer planetary gear set (PG3) arranged on the one side of the third clutch CL3 in the shaft direction; and a connection member (21 and 22) which connects each of the first clutch CL1, the second clutch CL2 and the third clutch CL3 to a common rotary element (S3) provided on the outer planetary gear set (PG3).SELECTED DRAWING: Figure 6

Description

The present invention relates to an automatic transmission with multiple clutches and multiple planetary gear sets.

As an example of the automatic transmission, the one disclosed in Patent Document 1 below is known. The automatic transmission described in Patent Document 1 includes three clutches and three planetary gear sets arranged in the axial direction. Specifically, in the automatic transmission of Patent Document 1, the first clutch (rear side clutch), the second clutch (intermediate clutch), and the third clutch (front side clutch) are arranged from one side (rear side) in the axial direction. A first planetary gear set, a second planetary gear set, and a third planetary gear set are arranged in this order on one side of the first clutch in the axial direction. The first clutch, the second clutch, and the third clutch are all connected to the sun gear (third sun gear) of the third planetary gear set.

JP 2020-169681 A

In the automatic transmission of Patent Document 1, the three planetary gear sets and the three clutches are arranged separately on one side and the other side in the axial direction. There is a problem that the power transmission path between the planetary gear set and the sun gear of the planetary gear set tends to be elongated. The lengthening of the power transmission path leads to an increase in the mass of a group of parts that constitute the power transmission path, that is, a group of rotating parts that rotate integrally with the third sun gear. When the mass of the rotating parts group increases, when the rotation speed of the third sun gear suddenly changes, the inertia of the rotating parts group slows down the change in the rotation of the third sun gear, degrading the shift responsiveness. There is a risk of Of course, if at least part of the rotating parts group is replaced with a lightweight part such as an aluminum die-cast product, an increase in the mass of the rotating parts group can be suppressed. However, if this is done, an increase in the unit price of parts cannot be avoided, which is not preferable in terms of manufacturing costs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an automatic transmission capable of reducing manufacturing costs and improving shift responsiveness.

In order to solve the above-mentioned problems, the automatic transmission of the present invention provides a first clutch and a second clutch arranged axially, and a third clutch arranged on one side of the first and second clutches in the axial direction. a clutch, an intermediate planetary gear set arranged between the first and second clutches and the third clutch, an outer planetary gear set arranged on one axial side of the third clutch, and the first clutch. , a connecting member that connects the second clutch and the third clutch to a common rotating element provided in the outer planetary gear set (Claim 1).

According to the present invention, the first and second clutches and the third clutch are axially distributed across the intermediate planetary gear set. simplifies the power transmission path between the first to third clutches and the common rotating element connected thereto, compared to the case where they are arranged together (similar structure to the above-mentioned Patent Document 1) be able to. As a result, the mass of the rotating part group can be reduced without taking special measures such as replacing the rotating part group that rotates integrally with the common rotating element with an expensive lightweight part, thereby reducing the manufacturing cost. It is possible to improve the shift responsiveness of the automatic transmission while suppressing the

Each of the first clutch and the second clutch may include a plurality of friction plates arranged in an axial direction and a tubular hub member engaged with inner peripheral edges of the friction plates. The 3-clutch may include a plurality of friction plates arranged in the axial direction and a cylindrical drum member engaged with the outer peripheral edges of the friction plates. In this case, the connecting member includes a first connecting member that connects the hub members of the first and second clutches and the drum member of the third clutch, and the drum member of the third clutch. and a second connecting member that connects to the rotating element (Claim 2).

According to this configuration, the first to third clutches and the common rotating element can be connected to each other with a simple and rational structure.

The third clutch includes a plurality of friction plates arranged in the axial direction, a cylindrical drum member engaged with outer peripheral edges of the friction plates, and a piston axially pressing the friction plates. be able to. In this case, the piston is arranged axially opposite a sub-piston which is supported by the transmission case and defines an engagement hydraulic chamber between itself and the transmission case, and presses the friction plate. It is preferable to include a rotatable main piston and a bearing that couples the sub-piston and the main piston so that they can rotate relative to each other (Claim 3).

According to this configuration, the engagement hydraulic chamber for the third clutch is formed between the sub-piston supported by the transmission case and the transmission case, not the rotatable main piston that presses the friction plates. In this case, since centrifugal force does not act on the engagement hydraulic chamber, it becomes unnecessary to provide a centrifugal balance chamber for canceling the influence of the centrifugal force. Therefore, it is possible to simplify the structure of the hydraulic supply system while ensuring the controllability of the piston by the hydraulic pressure supplied to the engagement hydraulic chamber.

Preferably, the drum member includes a peripheral wall portion that extends axially outside the friction plate in the radial direction and engages the outer peripheral edge of the friction plate, and a vertical wall portion that extends radially inward from one axial end of the peripheral wall portion. The main piston includes a wall portion and a plurality of inner projections extending from the radially inner end portion of the vertical wall portion toward the other side in the axial direction. a plurality of openings formed radially inward and through which the inner projections are inserted; and the connecting member connects the other end of the inner projection in the axial direction and the common rotating element. A downstream connecting member is included (Claim 4).

According to this configuration, the pressing portion of the main piston is arranged inside the drum member so that the pressing portion can press the friction plate, and the drum member is connected to the common rotating element via the downstream side connecting member. can do.

Preferably, the third clutch includes a return spring on the other side of the main piston in the axial direction for urging the main piston in a release direction for releasing pressure from the friction plate, and the return spring It is arranged radially inside the plate so as to overlap with the friction plate when viewed in the radial direction (claim 5).

According to this configuration, the axial dimension of the third clutch can be shortened, and the automatic transmission can be made compact in the axial direction.

Preferably, the return spring is arranged at a position facing the bearing with the main piston therebetween (Claim 6).

According to this configuration, it is possible to achieve a rational arrangement in which the bearing that pushes the main piston in the engagement direction and the return spring that pushes the main piston back in the release direction face each other in the axial direction.

As described above, according to the automatic transmission of the present invention, it is possible to achieve both suppression of manufacturing cost and improvement of shift response.

1 is a skeleton diagram showing the configuration of an automatic transmission according to an embodiment of the present invention; FIG. 2 is a cross-sectional view of the automatic transmission; FIG. 4 is an engagement table showing the relationship between the engagement/disengagement of each frictional engagement element and the speed. 3 is an enlarged sectional view enlarging a part of FIG. 2; FIG. FIG. 4 is an exploded perspective view of a third clutch; FIG. 5 is a view equivalent to FIG. 4 showing a colored rotating parts group that rotates integrally with the third sun gear. FIG. 5 is a cross-sectional view showing the structure of a comparative example in which the arrangement of a clutch and the like is different from that of the embodiment;

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

[Overall Configuration of Automatic Transmission]
1 and 2 are a skeleton diagram and a sectional view showing the configuration of an automatic transmission 1 according to an embodiment of the invention. The automatic transmission 1 shown in the drawing is a vertical automatic transmission mounted on an FR type (front engine/rear drive type) vehicle. That is, the automatic transmission 1 is a transmission that transmits the power of a drive source including an internal combustion engine arranged in the front portion of the vehicle to a propeller shaft while changing the speed. The power transmitted to the propeller shaft is transmitted to the rear wheels via the differential mechanism.

The automatic transmission 1 includes a transmission mechanism 10, a transmission case 11, an input shaft 12, an output shaft 13, and a valve body 14 (Fig. 2). The transmission mechanism 10 is a multistage transmission mechanism capable of achieving a plurality of gear stages with different gear ratios, and includes planetary gear sets (PG1 to PG4) described later, clutches and brakes (CL1 to CL3, BR1, BR2), and the like. of frictional engagement elements. The transmission case 11 is a case that accommodates the transmission mechanism 10 inside. The input shaft 12 is a shaft member that inputs power to the transmission mechanism 10, and is coaxially connected to the output shaft of the drive source. The output shaft 13 is a shaft member that outputs power from the transmission mechanism 10, and is coaxially connected to the propeller shaft. The input shaft 12 is arranged inside the transmission case 11 , and the output shaft 13 is arranged so as to protrude from the inside of the transmission case 11 to the outside.

The input shaft 12 and the output shaft 13 are arranged coaxially along the vehicle front-rear direction. That is, the input shaft 12 and the output shaft 13 are arranged so as to extend along the same axis X (FIG. 2) extending in the longitudinal direction of the vehicle. Axis X is a substantial central axis of transmission mechanism 10 of automatic transmission 1 . The automatic transmission 1 is mounted on the vehicle along its axis X with the input shaft 12 positioned on the front side of the vehicle and the output shaft 13 positioned on the rear side of the vehicle. For this reason, hereinafter, one side in a direction parallel to the axis X (the central axis of the input shaft 12 and the output shaft 13) of the automatic transmission 1 and away from the drive source (the right side in the figure) will be referred to as " The other side in the direction parallel to the axis X and closer to the drive source (the left side in the figure) is sometimes called the "front". Regarding the automatic transmission 1, the direction along the axis X may be called the "axial direction", and the direction perpendicular to the axis X may be called the "radial direction". Furthermore, the direction along the circumference of the circle centered on the axis X is sometimes called the "circumferential direction".

The transmission mechanism 10 includes a first planetary gear set PG1, a second planetary gear set PG2, a third planetary gear set PG3, and a fourth planetary gear set PG4, which are arranged axially. These first, second, third and fourth planetary gear sets PG1, PG2, PG3 and PG4 are arranged in this order from the front along the axial direction. Hereinafter, the planetary gear set will be abbreviated as "gear set" as appropriate. For example, the first planetary gear set PG1 is abbreviated as the first gear set PG1.

The first gear set PG1 includes a first sun gear S1, a first ring gear R1, and a first carrier C1 as rotating elements. The first carrier C1 supports a plurality of circumferentially spaced first pinions P1. Each first pinion P1 meshes with both the first sun gear S1 and the first ring gear R1.

The second gear set PG2 includes a second sun gear S2, a second ring gear R2, and a second carrier C2 as rotating elements. The second carrier C2 supports a plurality of second pinions P2 circumferentially spaced from each other. Each second pinion P2 meshes with both the second sun gear S2 and the second ring gear R2.

The third gear set PG3 includes a third sun gear S3, a third ring gear R3, and a third carrier C3 as rotating elements. The third carrier C3 supports a plurality of third pinions P3 circumferentially spaced from each other. Each third pinion P3 meshes with both the third sun gear S3 and the third ring gear R3.

The fourth gear set PG4 includes a fourth sun gear S4, a fourth ring gear R4, and a fourth carrier C4 as rotating elements. The fourth carrier C4 supports a plurality of fourth pinions P4 circumferentially spaced from each other. Each fourth pinion P4 meshes with both the fourth sun gear S4 and the fourth ring gear R4.

Here, in this embodiment, a double sun gear type gear set in which the sun gear S1 is axially divided into two is used as the first gear set PG1. On the other hand, as the other second to fourth gear sets PG2 to PG4, normal type gear sets in which the sun gear is not divided in the axial direction are used.

Specifically, the first sun gear S1 of the first gear set PG1 includes a front sun gear S1a and a rear sun gear S1b. The rear sun gear S1b is arranged separately behind the front sun gear S1a. The front sun gear S1a and the rear sun gear S1b have the same number of teeth and mesh with a common first pinion P1. Therefore, the rotational speeds of the front sun gear S1a and the rear sun gear S1b are always equal. That is, the front sun gear S1a and the rear sun gear S1b always rotate at the same speed, and when one stops rotating, the other also stops rotating.

The input shaft 12 is connected to the first carrier C1 via a power transmission member 18 passing between the split gears of the first sun gear S1 (that is, the front sun gear S1a and the rear sun gear S1b). The first sun gear S1 (more specifically, the rear sun gear S1b) is connected via a power transmission member 15 to the fourth sun gear S4. The second carrier C2 is connected via the power transmission member 16 to the fourth carrier C4. The output shaft 13 is connected to the fourth carrier C4.

The transmission mechanism 10 includes a first clutch CL1, a second clutch CL2, a third clutch CL3, a first brake BR1, and a friction engagement element for switching the power transmission path of the first to fourth gear sets PG1 to PG4. A second brake BR2 is provided.

The first clutch CL1 is arranged in the vicinity of the front side of the first gear set PG1, the second clutch CL2 is arranged further in front of the first clutch CL1, and the third clutch CL3 is arranged behind the second gear set PG2. It is That is, the first to third clutches CL1 to CL3 are arranged in the order of the second clutch CL2, the first clutch CL1, and the third clutch CL3 from the front side. Also, the combination of the first clutch CL1 and the second clutch CL2 and the third clutch CL3 face each other in the axial direction (front-rear direction) with the first gear set PG1 and the second gear set PG2 interposed therebetween. In other words, the first to third clutches CL1 to CL3 are such that the third clutch CL3 is positioned on one side (rear side) of the first and second gear sets PG1 and PG2 in the axial direction, and the shafts of the gear sets PG1 and PG2 They are arranged in two sets so that the remaining two clutches (first and second gear sets CL1 and CL2) are positioned on the other side (front side) of the direction.

The first brake BR1 and the second brake BR2 are arranged separately before and after the first to third clutches CL1 to CL3. Specifically, the first brake BR1 is arranged further forward of the second clutch CL2, which is the most front clutch. The second brake BR2 is arranged further rearward of the third clutch CL3, which is the rearmost clutch (and forward of the third gear set PG3).

The first clutch CL1 is a frictional engagement element that connects and disconnects the input shaft 12 and the first carrier C1 with the third sun gear S3. Specifically, the first clutch CL1 includes a rotatable cylindrical drum member 31 connected to the first carrier C1 and a rotatable drum member 31 connected to the third sun gear S3 via power transmission members 21, 22 and the like. A cylindrical hub member 32, a plurality of friction plates 33 arranged between the drum member 31 and the hub member 32, and a piston 34 capable of axially pressing the friction plates 33 are provided. The first clutch CL1 connects and disconnects the input shaft 12 and the first carrier C1 with the third sun gear S3 in accordance with the pressing of the piston 34 against the friction plate 33 or the release of the pressing. Here, the hub member 32 of the first clutch CL1 also serves as a hub member for the second clutch CL2, which will be described later. For this reason, the hub member 32 is hereinafter referred to as the common hub member 32 .

The second clutch CL2 is a frictional engagement element that connects and disconnects the first ring gear R1, the second sun gear S2, and the third sun gear S3. Specifically, the second clutch CL2 includes a rotatable cylindrical drum member 41 connected to the first ring gear R1 and the second sun gear S2 via a power transmission member 23, and a power transmission member 21 connected to the third sun gear S3. , 22, etc., a plurality of friction plates 43 arranged between the drum member 41 and the hub member 32, and a piston 44 capable of pressing the friction plates 43 in the axial direction. Prepare. The second clutch CL2 connects and disconnects the first ring gear R1 and the second sun gear S2 with the third sun gear S3 in accordance with the pressing of the piston 44 against the friction plate 43 or the release of the pressing.

The third clutch CL3 is a frictional engagement element that connects and disconnects the second ring gear R2 and the third sun gear S3. Specifically, the third clutch CL3 includes a rotatable cylindrical drum member 51 connected to the third sun gear S3 via the power transmission member 22, and a rotatable cylindrical drum member 51 connected to the second ring gear R2. It comprises a hub member 52, a plurality of friction plates 53 arranged between the drum member 51 and the hub member 52, and a piston 54 capable of pressing the friction plates 53 in the axial direction. The third clutch CL3 connects and disconnects the second ring gear R2 and the third sun gear S3 according to the pressing of the piston 54 against the friction plate 53 or the release of the pressing.

The first brake BR1 is a frictional engagement element that connects and disconnects the transmission case 11 and the first sun gear S1 (specifically, the front sun gear S1a). Specifically, the first brake BR1 includes a cylindrical drum member 61 fixed to the transmission case 11, and a rotatable cylindrical hub member 62 connected to the front sun gear S1a via the power transmission member 17. , a plurality of friction plates 63 arranged between a drum member 61 and a hub member 62, and a piston 64 capable of pressing the friction plates 63 in the axial direction. The first brake BR1 connects and disconnects the transmission case 11 and the first sun gear S1 in response to pressing of the piston 64 against the friction plate 63 or release of the pressing.

The second brake BR2 is a friction engagement element that connects and disconnects the transmission case 11 and the third ring gear R3. Specifically, the second brake BR2 includes a cylindrical drum member 71 fixed to the transmission case 11, a rotatable cylindrical hub member 72 connected to the third ring gear R3, the drum member 71 and the hub. A plurality of friction plates 73 arranged between members 72 and a piston 74 capable of axially pressing the friction plates 73 are provided. The second brake BR2 connects and disconnects the transmission case 11 and the third ring gear R3 in response to pressing of the piston 74 against the friction plate 73 or release of the pressing.

The valve body 14 is a hydraulic circuit device for controlling engagement and disengagement of each of the frictional engagement elements (clutches CL1 to CL3 and brakes BR1 and BR2) described above. Although detailed illustration is omitted, for example, the valve body 14 includes a large number of oil passages through which oil supplied to each friction engagement element flows, and a large number of solenoid valves that switch the flow of each oil passage.

In the automatic transmission 1 structured as described above, the first gear set PG1 and the second gear set PG2 correspond to the "intermediate planetary gear set" in the present invention, and the third gear set PG3 corresponds to the "outer planetary gear set" in the present invention. Equivalent to Moreover, the power transmission member 21 corresponds to the "first connecting member" in the present invention, and the power transmitting member 22 corresponds to the "second connecting member" or the "downstream side connecting member" in the present invention.

FIG. 3 is an engagement table showing the relationship between the engagement/disengagement of each frictional engagement element and the speed. As shown in the figure, in the automatic transmission 1 of the present embodiment, nine types of forward speed 1 to 8 and reverse speed are selected according to the selective engagement or disengagement of each friction engagement element by the valve body 14 described above. A gear is achieved. In the fastening table of FIG. 3, a circle indicates that the corresponding frictional engagement element is engaged, and a blank indicates that the corresponding frictional engagement element is released (disengaged).

Specifically, each gear stage is achieved as follows. That is, 1st speed is achieved by engaging the first clutch CL1, the first brake BR1, and the second brake BR2. 2nd speed is achieved by engaging the second clutch CL2, the first brake BR1, and the second brake BR2. Third speed is achieved by engaging the first clutch CL1, the second clutch CL2, and the second brake BR2. 4th speed is achieved by engaging the second clutch CL2, the third clutch CL3, and the second brake BR2. Fifth speed is achieved by engaging the first clutch CL1, the third clutch CL3, and the second brake BR2. Sixth speed is achieved by engaging the first clutch CL1, the second clutch CL2, and the third clutch CL3. 7th speed is achieved by engaging the first clutch CL1, the third clutch CL3, and the first brake BR1. Eighth speed is achieved by engaging the second clutch CL2, the third clutch CL3, and the first brake BR1. Reverse speed is achieved by engaging the third clutch CL3, the first brake BR1, and the second brake BR2.

[Detailed structure of each clutch]
Next, a more detailed structure of each of the clutches CL1 to CL3 described above will be described. FIG. 4 is an enlarged sectional view enlarging a part of FIG. As shown in FIGS. 2 and 4, the first clutch CL1 includes, in addition to the drum member 31, the common hub member 32, the friction plate 33, and the piston 34 described above, a piston support member 35, a partition member 36, a return and a spring 37 . The piston support member 35 is a member that axially movably supports the piston 34 . The return spring 37 is a spring that biases the piston 34 in the releasing direction (the direction away from the friction plate 33; rearward here). The partition member 36 is a member for making the space in which the return spring 37 is arranged a hydraulic chamber (a centrifugal balance chamber 39 to be described later).

The drum member 31 includes a peripheral wall portion 31a extending axially (forward and backward) on the radially outer side of the friction plate 33, and a vertical wall portion 31b extending radially inward from the rear end of the peripheral wall portion 31a. The vertical wall portion 31b is coupled to the first carrier C1 by welding its radially inner end portion to the axially intermediate portion of the first carrier C1.

The common hub member 32 includes a peripheral wall portion 32a extending in the axial direction (front-rear direction), a vertical wall portion 32b extending radially inward from the front portion of the peripheral wall portion 32a, and a radial wall portion 32b extending forward from the radially inner end portion of the vertical wall portion 32b. and a shaft portion 32c extending to the . The peripheral wall portion 32a has a rear peripheral wall 32a1 and a front peripheral wall 32a2 that are axially continuous. The rear peripheral wall 32a1 is arranged to face the peripheral wall portion 31a of the drum member 31 from the inside in the radial direction, and the front peripheral wall 32a2 is arranged to face the peripheral wall portion 41a of the drum member 41 from the inside in the radial direction. be. The rear side peripheral wall 32a1 functions as a hub that holds the friction plates 33 of the first clutch CL1 (the hub side friction plates 33b, which will be described later in detail), and the front side peripheral wall 32a2 serves as the friction plate 43 of the second clutch CL2 (the details, which will be described later). It functions as a hub that holds the hub-side friction plate 43b).

The peripheral wall portion 32a (rear side peripheral wall 32a1) extends rearward to a position surrounding the outer periphery of the front portion of the first pinion P1. In other words, the first gear set PG1 is arranged close to the first clutch CL1 so that the front portion of the first pinion P1 is inside the common hub member 32 . In this manner, the first clutch CL1 and the first gear set PG1 are arranged side by side in the front-rear direction so as to partially overlap when viewed in the radial direction.

The friction plates 33 include a plurality of drum-side friction plates 33a that engage with the inner peripheral surface of the peripheral wall portion 31a of the drum member 31, and a plurality of hub-side friction plates that engage with the outer peripheral surface of the peripheral wall portion 32a of the common hub member 32. 33b. Each drum-side friction plate 33a is attached to the drum member 31 in such a manner that its outer peripheral edge is spline-fitted to the peripheral wall portion 31a of the drum member 31 so as to be rotatable together with the drum member 31 and axially movable. installed. Each hub-side friction plate 33b is rotatable integrally with the common hub member 32 and axially movable by spline-fitting the inner peripheral edge thereof to the rear side peripheral wall 32a1 of the peripheral wall portion 32a of the common hub member 32. are attached to the common hub member 32 in the same state. The drum-side friction plates 33a and the hub-side friction plates 33b are attached to the drum member 31 and the common hub member 32, respectively, while being alternately arranged in the axial direction.

The piston 34 includes a pressing portion 34a facing the friction plate 33 from behind, an extending portion 34b extending forward from the radially inner end of the pressing portion 34a, and a radially extending portion extending from the front end of the extending portion 34b. and an inwardly extending pressure receiving portion 34c. The pressing portion 34a of the piston 34 is spline-fitted to the peripheral wall portion 31a of the drum member 31, so that the piston 34 is held by the drum member 31 so as to be rotatable together with the drum member 31 and axially movable. there is

The piston support member 35 includes a support portion 35a that is hook-shaped in cross section so as to follow the shape of the pressure receiving portion 34c of the piston 34, and a shaft portion 35b that extends forward from the radially inner end of the support portion 35a. including. The piston 34 is axially movably supported by the piston support member 35 by fitting the pressure receiving portion 34c thereof to the piston support member 35 from the front.

The piston support member 35 is coupled to the first carrier C1 by welding the rear surface of the support portion 35a to the front end portion of the first carrier C1. Here, the first carrier C1 is coupled not only to the piston support member 35, but also to the drum member 31 as described above. Also, the piston 34 is engaged with the drum member 31 so as not to rotate relative to it. Therefore, the first carrier C1, the drum member 31, the piston 34, and the piston support member 35 all rotate at the same number of revolutions.

The extension portion 34b of the piston 34 is formed with an opening h1. The openings h1 are openings for avoiding interference with the first pinion P1, and are provided at a plurality of positions in the circumferential direction corresponding to the first pinion P1.

A fastening hydraulic chamber 38 is formed between the pressure receiving portion 34 c of the piston 34 and the piston support member 35 . The hydraulic pressure supplied to the engagement hydraulic chamber 38 acts as a force that pushes the pressure receiving portion 34c forward. As a result, the pressing portion 34a of the piston 34 presses the friction plate 33, and the first clutch CL1 is engaged.

The partition member 36 is arranged adjacent to the front side of the pressure receiving portion 34 c of the piston 34 . A centrifugal balance chamber 39 is formed between the partition member 36 and the pressure receiving portion 34c. The centrifugal balance chamber 39 is a hydraulic chamber for canceling hydraulic pressure fluctuation due to centrifugal force acting on the engagement hydraulic chamber 38 . The centrifugal balance chamber 39 is formed to face the engagement hydraulic chamber 38 with the pressure receiving portion 34c interposed therebetween.

A return spring 37 is arranged in a centrifugal balance chamber 39 . The return spring 37 is sandwiched between the pressure-receiving portion 34c of the piston 34 and the partition member 36, and exerts an elastic force to separate the piston 34 and the partition member 36 from each other. Due to this elastic force, the piston 34 is constantly urged in the release direction away from the friction plate 33, that is, in the rearward direction. When the first clutch CL1 is engaged, a required hydraulic pressure is supplied to the engagement hydraulic chamber 38 so that the piston 34 is pushed forward (in the engagement direction) against the urging force of the return spring 37 .

The common hub member 32 and the piston support member 35 are arranged axially so that the vertical wall portion 32b of the common hub member 32 is on the front side of the piston support member 35, and are rotatable around the outer periphery of the common boss member 80. Supported. The boss member 80 is a cylindrical member concentric with the input shaft 12 and fixed to the transmission case 11 . The common hub member 32 is rotatably supported about the axis X of the automatic transmission 1 by externally inserting the shaft portion 32 c of the common hub member 32 into the boss member 80 . Similarly, the piston support member 35 is rotatably supported about the axis X by externally inserting the shaft portion 35 b of the boss member 80 . The shaft portion 32c of the common hub member 32 and the shaft portion 35b of the piston support member 35 are axially adjacent to each other, and a thrust bearing 81 is arranged between them. The common hub member 32 and the piston support member 35 are rotatably supported with the thrust bearing 81 interposed therebetween.

The power transmission member 17 is coaxially inserted inside the boss member 80 , and the input shaft 12 is coaxially inserted inside the power transmission member 17 . The input shaft 12 and the power transmission member 17 are supported so as to be relatively rotatable about a common axis X. As shown in FIG. A rear end portion of the power transmission member 17 is spline-fitted to the inner peripheral surface of the first sun gear S1 (specifically, the front sun gear S1a). The rear end of the input shaft 12 is spline-fitted to the inner peripheral surface of the power transmission member 18 .

Inside the boss member 80, an axially extending oil passage e1 is formed. Further, an oil passage e2 communicating with the oil passage e1 is formed in the piston support member 35 . The oil passage e2 communicates with the engagement hydraulic chamber 38 . By supplying and discharging hydraulic pressure to and from the engagement hydraulic chamber 38 through the oil passage e2, the piston 34 is pressed against the friction plate 33, or the pressure is released. When the piston 34 is pressed against the friction plates 33, the drum-side friction plates 33a and the hub-side friction plates 33b are brought into close contact so as not to rotate relative to each other, and the first clutch CL1 is engaged. When the pressure of the friction plates 33 by the piston 34 is released, relative rotation between the drum-side friction plates 33a and the hub-side friction plates 33b is permitted, and the first clutch CL1 is released.

Although not shown, the piston support member 35 is also formed with an oil passage connecting the centrifugal balance chamber 39 and the internal oil passage e1 of the boss member 80 . Through the oil passage, hydraulic pressure is supplied to the centrifugal balance chamber 39 for canceling hydraulic pressure fluctuations in the engagement hydraulic chamber 38 due to centrifugal force. Here, the oil passage e1 of the boss member 80 includes a plurality of independent unit oil passages arranged at intervals in the circumferential direction. The oil passage leading to the centrifugal balance chamber 39 and the oil passage e2 leading to the engagement hydraulic chamber 38 are formed to communicate with different unit oil passages. The same applies to the oil passage e3 for the engagement hydraulic chamber 48 and the oil passage for the centrifugal balance chamber 49, which will be described later.

The second clutch CL<b>2 includes a piston support member 45 , a partition member 46 and a return spring 47 in addition to the drum member 41 , common hub member 32 , friction plates 43 and piston 44 described above. The piston support member 45 is a member that axially movably supports the piston 44 . The return spring 47 is a spring that biases the piston 44 in the releasing direction (the direction away from the friction plate 43; forward here). The partition member 46 is a member for making the space in which the return spring 47 is arranged a hydraulic chamber (a centrifugal balance chamber 49 to be described later).

The drum member 41 includes a peripheral wall portion 41a extending axially (forward and backward) on the radially outer side of the friction plate 43, and a vertical wall portion 41b extending radially inward from the rear end of the peripheral wall portion 41a. The vertical wall portion 41 b is coupled to the radially outer end portion of the power transmission member 23 . The power transmission member 23 is coupled to the first ring gear R1 by welding or the like, and is coupled to the second sun gear S2 by spline fitting. In other words, the power transmission member 23 connects the first ring gear R1, the second sun gear S2, and the drum member 41 to each other.

The friction plates 43 include a plurality of drum-side friction plates 43 a that engage with the inner peripheral surface of the peripheral wall portion 41 a of the drum member 41 , and a plurality of hub-side friction plates that engage with the outer peripheral surface of the peripheral wall portion 32 a of the common hub member 32 . 43b. Each drum-side friction plate 43a is attached to the drum member 41 in a state that it can rotate integrally with the drum member 41 and move in the axial direction by spline-fitting its outer peripheral edge to the peripheral wall portion 41a of the drum member 41. installed. Each hub-side friction plate 43b is rotatable integrally with the common hub member 32 and axially movable by spline-fitting its inner peripheral edge to the front side peripheral wall 32a2 of the peripheral wall portion 32a of the common hub member 32. attached to the common hub member 32 in the same state. The drum-side friction plates 43a and the hub-side friction plates 43b are attached to the drum member 41 and the common hub member 32, respectively, while being alternately arranged in the axial direction.

The piston 44 includes a pressing portion 44a and a radially inner pressure receiving portion 44b. The pressing portion 44a is arranged to face the friction plate 43 from the front. The pressure receiving portion 44b is arranged to face the vertical wall portion 32b of the common hub member 32 from the front.

The piston support member 45 is rotatably supported on the outer circumference of the shaft portion 32c of the common hub member 32. As shown in FIG. The piston 44 is axially movably supported by the piston support member 45 by fitting the pressure receiving portion 44b thereof to the piston support member 45 from behind.

A fastening hydraulic chamber 48 is formed between the pressure receiving portion 44 b of the piston 44 and the piston support member 45 . The hydraulic pressure supplied to the engagement hydraulic chamber 48 acts as a force that pushes the pressure receiving portion 44b rearward. As a result, the pressing portion 44a of the piston 44 presses the friction plate 43, and the second clutch CL2 is engaged.

The partition member 46 is provided so as to seal between the pressure receiving portion 44 b of the piston 44 and the vertical wall portion 32 b of the common hub member 32 . Thereby, a centrifugal balance chamber 49 is formed between the pressure receiving portion 44b and the vertical wall portion 32b. The centrifugal balance chamber 49 is a hydraulic chamber for canceling hydraulic pressure fluctuation due to centrifugal force acting on the engagement hydraulic chamber 48 . The centrifugal balance chamber 49 is formed to face the engagement hydraulic chamber 48 with the pressure receiving portion 44b interposed therebetween.

A return spring 47 is arranged in a centrifugal balance chamber 49 . The return spring 47 is sandwiched between the pressure receiving portion 44b of the piston 44 and the vertical wall portion 32b of the common hub member 32, and always biases the piston 44 forward (in the release direction). When the second clutch CL2 is engaged, a required hydraulic pressure is supplied to the engagement hydraulic chamber 48 so that the piston 44 is pushed rearward (in the engagement direction) against the biasing force of the return spring 47 .

An oil passage e3 communicating with the internal oil passage e1 of the boss member 80 is formed in the shaft portion 32c of the common hub member 32. As shown in FIG. The oil passage e3 communicates with the engagement hydraulic chamber 48 . By supplying and discharging hydraulic pressure to and from the engagement hydraulic chamber 48 through the oil passage e3, the piston 44 is pressed against the friction plate 43, or the pressure is released. When the piston 44 is pressed against the friction plates 43, the drum-side friction plates 43a and the hub-side friction plates 43b are brought into close contact so as not to rotate relative to each other, and the second clutch CL2 is engaged. When the pressure of the friction plates 43 by the piston 44 is released, relative rotation between the drum-side friction plates 43a and the hub-side friction plates 43b is allowed, and the second clutch CL2 is released.

Although not shown, the shaft portion 32c of the common hub member 32 is also formed with an oil passage that communicates the centrifugal balance chamber 49 and the internal oil passage e1 of the boss member 80 with each other. Through the oil passage, hydraulic pressure is supplied to the centrifugal balance chamber 49 for canceling hydraulic pressure fluctuations in the engagement hydraulic chamber 48 due to centrifugal force.

FIG. 5 is an exploded perspective view of the third clutch CL3. As shown in FIG. 5 and previous FIGS. 2 and 4, the third clutch CL3 includes a return spring 57 in addition to the drum member 51, hub member 52, friction plate 53, and piston 54 described above. The return spring 47 is a spring that biases the piston 54 in the releasing direction (the direction away from the friction plate 43; rearward here).

The drum member 51 includes a peripheral wall portion 51a extending in the axial direction (front-rear direction) on the radially outer side of the friction plate 53, a vertical wall portion 51b extending radially inward from the rear end of the peripheral wall portion 51a, and a diameter of the vertical wall portion 51b. and an inner projection 51c extending forward from the directionally inner end. As shown in FIG. 5, the inner projections 51c are a plurality of projections arranged along the inner edge of the vertical wall portion 51b at regular intervals in the circumferential direction, and are formed in a so-called comb shape. Each inner projection 51c is arranged so as to penetrate the piston 54 through an opening h2, which will be described later.

A front end portion of the peripheral wall portion 51 a of the drum member 51 is coupled to a rear end portion of the power transmission member 21 . Specifically, the power transmission member 21 includes a peripheral wall portion 21a extending in the axial direction (front-rear direction) and a vertical wall portion 21b extending radially inward from the front end of the peripheral wall portion 21a. The vertical wall portion 21b is formed to extend radially in front of the first and second clutches CL1 and CL2. The peripheral wall portion 21 a extends axially outside the first and second clutches CL<b>1 and CL<b>2 in the radial direction and is arranged to face the peripheral wall portion 51 a of the drum member 51 . The radially inner end of the vertical wall portion 21b is spline-fitted to the outer peripheral surface of the shaft portion 32c of the common hub member 32 (the hub member 32 shared by the first and second clutches CL1 and CL2). A rear end portion of the peripheral wall portion 21a is connected to a front end portion of the peripheral wall portion 51a of the drum member 51 by spline fitting. In other words, the drum member 51 is connected with the common hub member 32 via the power transmission member 21 .

The inner projection 51 c of the drum member 51 is coupled to the radially inner end of the power transmission member 22 . Specifically, the power transmission member 22 includes a vertical wall portion 22a facing the piston 54 from the front, a flange portion 22b extending short rearward from the radially outer end of the vertical wall portion 22a, and the vertical wall portion 22a. and a shaft portion 22c extending rearwardly from the radially inner end. The shaft portion 22c is formed radially inward of the piston 54 so as to extend in the axial direction (front-rear direction). The rear end portion of the shaft portion 22c is spline-fitted to the inner peripheral surface of the third sun gear S3, and the flange portion 22b is connected to the inner projection 51c of the drum member 51 by welding or the like. In other words, the drum member 51 is connected via the power transmission member 22 to the third sun gear S3.

As described above, the drum member 51 is connected to the common hub member 32 and the third sun gear S3 via the power transmission members 21 and 22, respectively. This means that the first clutch CL1, the second clutch CL2 and the third clutch CL3 are connected to the rotating elements of the same planetary gear set. That is, the common hub member 32 of the first and second clutches CL1 and CL2 is connected to the drum member 51 of the third clutch CL3 via the power transmission member 21, and the drum member 51 of the third clutch CL3 is connected to the power transmission member 22. , the first to third clutches CL1 to CL3 are connected to the common third sun gear S3.

Power transmission member 22 is rotatably supported by bearing 92 inside partition wall portion 112 of transmission case 11 . That is, the transmission case 11 includes a drum-shaped case main body 111 and the partition wall portion 112 projecting radially inwardly from the case main body 111 . The partition wall portion 112 is provided between the third clutch CL3 and the second brake BR2 in the axial direction. The partition wall portion 112 has an axially extending boss portion 113 at its radially inner end portion. The boss portion 113 includes a front boss 113a projecting forward and a rear boss 113b projecting rearward. The rear boss 113b is located slightly radially outward of the front boss 113a, and the bearing 92 is arranged between the rear boss 113b and the shaft portion 22c of the power transmission member 22. As shown in FIG.

The power transmission member 16 is coaxially inserted inside the power transmission member 22 , and the power transmission member 15 is coaxially inserted inside the power transmission member 16 . A front end portion of the power transmission member 15 is spline-fitted to the inner peripheral surface of the first sun gear S1 (specifically, the rear sun gear S1b). A front end portion of the power transmission member 16 is coupled to the second carrier C2 via an auxiliary coupling member 90. As shown in FIG.

The hub member 52 includes a peripheral wall portion 52a extending in the axial direction (front-rear direction) and a support body 52b that supports the peripheral wall portion 52a. The support 52b is fitted around the power transmission member 16 so as to be relatively rotatable. The support 52b has vertical walls extending radially outward from the outer periphery of the power transmission member 16 . The peripheral wall portion 52a is joined to the rear surface of the vertical wall of the support 52b by welding or the like so as to protrude rearward from the vertical wall. The peripheral wall portion 52a faces the peripheral wall portion 51a of the drum member 51 from the radially inner side. The hub member 52 is connected to the second ring gear R2 by, for example, welding the radially outer end of the support 52b to the rear end of the second ring gear R2.

The friction plates 53 include a plurality of drum-side friction plates 53a that engage with the inner peripheral surface of the peripheral wall portion 51a of the drum member 51, and a plurality of hub-side friction plates 53b that engage with the outer peripheral surface of the peripheral wall portion 52a of the hub member 52. including. Each drum-side friction plate 53a is attached to the drum member 51 in such a manner that the outer peripheral edge thereof is spline-fitted to the peripheral wall portion 51a of the drum member 51 so as to be rotatable together with the drum member 51 and axially movable. installed. Each hub-side friction plate 53b is attached to the hub member 52 in a state in which its inner peripheral edge is spline-fitted to the peripheral wall portion 52a of the hub member 52 so as to be rotatable together with the hub member 52 and axially movable. installed. The drum-side friction plates 53a and the hub-side friction plates 53b are attached to the drum member 51 and the hub member 52, respectively, while being alternately arranged in the axial direction.

The piston 54 includes a main piston 54a arranged behind the friction plate 53, a sub-piston 54b arranged further behind the main piston 54a, and bearings arranged between the main piston 54a and the sub-piston 54b. 54c. The main piston 54 a is a piston component that directly presses the friction plate 53 . The sub-piston 54b is a piston component that receives hydraulic pressure supplied to an engagement hydraulic chamber 58, which will be described later, and moves in the axial direction. The bearing 54c is a bearing that allows the rotation of the main piston 54a with respect to the sub-piston 54b and connects the two. In other words, the piston 54 is a composite piston in which two piston parts (the main piston 54a and the sub-piston 54b) that are axially movable together and relatively rotatable are combined.

The sub-piston 54 b is supported by the partition wall portion 112 of the transmission case 11 . Specifically, the sub-piston 54b is supported by the partition 112 so as to be axially movable along the outer peripheral surface of the front boss 113a of the partition 112 . However, rotation of the sub-piston 54b with respect to the partition wall portion 112 (transmission case 11) is disabled. In other words, the sub-piston 54b is supported by the transmission case 11 so as to be axially movable but not rotatable about its axis.

The main piston 54a is axially movably supported along the outer peripheral surface of the front boss 113a of the partition wall 112 on the front side of the sub-piston 54b. The main piston 54a has a pressing portion 54a1 facing the friction plate 53 from behind. The main piston 54a is held by the drum member 51 so as to be rotatable together with the drum member 51 and axially movable by spline-fitting the pressing portion 54a1 to the peripheral wall portion 51a of the drum member 51. ing.

Openings h2 are formed at a plurality of locations in the circumferential direction of the main piston 54a. The plurality of openings h2 are provided radially inward of the pressing portion 54a1 of the main piston 54a (diametrically intermediate portion of the main piston 54a), and are arranged so as to be spaced apart in the circumferential direction. (See especially FIG. 5). Moreover, the plurality of openings h2 are provided at positions corresponding to the plurality of inner protrusions 51c of the drum member 51, and are formed so as to be able to receive the plurality of inner protrusions 51c. That is, the inner protrusion 51c of the drum member 51 axially penetrates the main piston 54a through the opening h2 of the main piston 54a. Then, the flange portion 22b of the power transmission member 22 is joined to the front end portion of the inner protrusion 51c by welding or the like while the inner protrusion 51c penetrates the main piston 54a (inserted through the opening h2). In other words, the drum member 51 is connected to the power transmission member 22 while three-dimensionally crossing the main piston 54a.

A fastening hydraulic chamber 58 is formed between the sub-piston 54 b and the partition wall portion 112 of the transmission case 11 . The hydraulic pressure supplied to the engagement hydraulic chamber 58 acts as a force that pushes the sub-piston 54b forward. By receiving this force, the sub-piston 54b moves forward, and the main piston 54a moves forward together with the sub-piston 54b. As a result, the pressing portion 54a1 of the main piston 54a presses the friction plate 53, and the third clutch CL3 is engaged.

An oil passage e4 communicating with the engagement hydraulic chamber 58 is formed in the partition wall portion 112 of the transmission case 11 . By supplying and discharging hydraulic pressure to and from the engagement hydraulic chamber 58 through the oil passage e4, the piston 54 (specifically, the main piston 54a) is pressed against the friction plate 53 or the pressure is released. When the piston 54 is pressed against the friction plate 53, the drum-side friction plate 53a and the hub-side friction plate 53b are in close contact with each other so as not to rotate relative to each other, and the third clutch CL3 is engaged. When the pressure of the friction plates 53 by the piston 54 is released, relative rotation between the drum-side friction plates 53a and the hub-side friction plates 53b is permitted, and the third clutch CL3 is released.

The return spring 57 is arranged so as to be sandwiched between the vertical wall portion 22a of the power transmission member 22 and the main piston 54a. Such a return spring 57 exerts an elastic force that separates the main piston 54a and the vertical wall portion 22a from each other. Due to this elastic force, the piston 54 is constantly urged in the release direction away from the friction plate 53, that is, in the rearward direction. When the third clutch CL3 is engaged, a required hydraulic pressure is supplied to the engagement hydraulic chamber 58 so that the piston 54 is pushed forward (in the engagement direction) against the biasing force of the return spring 57 .

The axial position of the return spring 57 is such that at least part of the return spring 57 is hidden inside the friction plate 53, in other words, the position is such that the return spring 57 and the friction plate 53 overlap each other when viewed in the radial direction. is set. In this embodiment, the axial position of the return spring 57 is set such that the rear portion of the friction plate 53 and the front portion of the return spring 57 overlap each other when viewed in the radial direction. The radial position of the return spring 57 is set so that the return spring 57 faces the bearing 54c with the main piston 54a interposed therebetween.

Here, since the engagement hydraulic chamber 58 for the third clutch CL3 is a non-rotating hydraulic chamber formed between a portion (partition wall portion 112) of the transmission case 11 and the sub-clutch 48b, the internal hydraulic pressure Not affected by centrifugal force. Therefore, unlike the above-described first and second clutches CL1 and CL2, the third clutch CL3 is not provided with a centrifugal balance chamber.

[Effect]
As described above, the automatic transmission 1 of the present embodiment includes the first to third clutches CL1 to CL3 arranged in the front-rear direction along the axis X, and the third clutch CL3 located on the rearmost side among them. The first and second gear sets PG1, PG2 arranged between the other two clutches (that is, the first and second clutches CL1, CL2), and the third clutch CL3 arranged behind the third clutch CL3. and a gear set PG3. Also, the first to third clutches CL1 to CL3 are all connected to the third sun gear S3 of the third gear set PG3. According to such a configuration, there is an advantage that the mass of the rotating parts group connected to the third sun gear S3 can be reduced, and the speed change responsiveness of the automatic transmission 1 can be improved.

FIG. 6 is a view equivalent to FIG. 4 showing in color a group of rotating parts that are connected to the third sun gear S3 and rotate together with the third sun gear S3. As shown in FIG. 6, the rotating parts group that rotates integrally with the third sun gear S3 in the above embodiment are mainly the common hub member 32 of the first and second clutches CL1 and CL2 and the piston of the second clutch CL2. 44 and piston support member 45, drum member 51 and main piston 54a of third clutch CL3, power transmission member 21 connecting common hub member 32 and drum member 51, drum member 51 and third sun gear S3. It is the power transmission member 22 to be connected. In the above embodiment, the third clutch CL3 is arranged between the first and second gear sets PG1, PG2 and the third gear set PG3, thereby simplifying the power transmission path compared to the comparative example shown below, for example. It is possible to reduce the mass of the rotating part group that constitutes the power transmission path.

FIG. 7 is a cross-sectional view showing the structure of a comparative example in which the arrangement of the clutch and the like is different from that of the above embodiment. The automatic transmission 1' of this comparative example has a first clutch CL1', a second clutch CL2' and a 3 clutches CL3' are provided. Further, the automatic transmission 1' of the comparative example has a first gear set PG1', a second gear set PG2' and a A third gearset PG3' is provided. Unlike the above-described embodiment, the comparative example does not employ a layout in which clutches and gear sets are arranged alternately in the axial direction. That is, in the comparative example, the second clutch CL2', the first clutch CL1', and the third clutch CL3' are arranged in this order from the front side, and the first to third clutches CL3' are arranged behind the rearmost third clutch CL3'. The third gear sets PG1' to PG3' are arranged in this order. The third clutch CL3' and the first gear set PG1' are arranged so as to partially overlap, but unlike the above embodiment, no gear set is arranged between the two clutches.

In the automatic transmission 1' of the comparative example, the rotating parts group rotating integrally with the third sun gear S3' of the third gear set PG3' are mainly the drum member 51' and the piston 54' of the third clutch CL3', and the third clutch CL3'. A hub member 31', a piston 34' and a piston support member 35' of the first clutch CL1'; a hub member 42', a piston 44' and a piston support member 45' of the second clutch CL2'; They are two power transmission members 21' and 22' that connect with the sun gear S3'. In FIG. 7, these rotating parts groups are colored in the same way as in FIG. 6 described above. As shown in FIG. 7, in the comparative example, the drum member 51' of the third clutch CL3' is arranged radially inside the power transmission member 21'. Also, the drum member 51' is the farthest rotating component from the third sun gear S3' on the power transmission path. In order to transmit such rotation of the drum member 51' to the third sun gear S3', in the comparative example, the drum member 51' of the third clutch CL3' is coupled with the hub member 42' of the second clutch CL2'. . Specifically, the shaft portion 51a' of the drum member 51' is greatly extended forward, and the front end portion of the shaft portion 51a' enlarged (elongated) by the extension becomes the hollow shaft of the hub member 42'. It is inserted into and connected to portion 42a'. As described above, in the comparative example, the drum member 51' is inevitably increased in size or the power transmission path is elongated. tend to be large. In the comparative example, the hub member 31' of the first clutch CL1' is integrated with the drum member 51' of the third clutch CL3', thereby reducing the weight to some extent. is large, and the mass of the rotating parts group tends to increase.

On the other hand, in the embodiment shown in FIG. 6, as is clear from a comparison with FIG. 7 (comparative example), the power transmission path to the third sun gear S3 is simple, and the drum member of the third clutch CL3 The axial dimension of 51 is relatively small. As a result, it is possible to reduce the mass of the colored rotating parts group including the drum member 51 , and improve the shift response of the automatic transmission 1 . If the mass of the rotating parts that rotate integrally with the third sun gear S3 is large, the inertia of the rotating parts will cause the third sun gear S3 to become unsteady during a shift in which the rotation speed of the third sun gear S3 suddenly changes. There is a risk that the change in the rotation speed of S3 will slow down and the shift response will deteriorate. On the other hand, according to the above-described embodiment, in which the mass of the rotating parts that rotate together with the third sun gear S3 can be reduced, the rotation speed of the third sun gear S3 can be changed quickly during gear shifting, and the gear shift response is improved. can be improved.

Even in the comparative example shown in FIG. 7, if at least part of the colored rotating parts are replaced with lightweight parts such as aluminum die-cast products, the mass of the rotating parts can be reduced and the shift responsiveness can be improved. can be improved. However, in this case, an increase in the unit price of parts cannot be avoided, which is not preferable in terms of manufacturing costs. On the other hand, in the above-described embodiment, the size (volume) of the rotating parts group itself is sufficiently smaller than that of the comparative example, so the mass of the rotating parts group can be kept low without making modifications that increase the cost as described above. Therefore, it is possible to suppress the manufacturing cost and achieve good shift response.

Further, in the above embodiment, the drum member 31 and the piston support member 35 of the first clutch CL1 are connected to the first carrier C1, so the piston 34 and the piston support member 35 are mechanically separated from the third sun gear S3. be able to. That is, the piston 34 and the piston support member 35 rotate integrally with the first carrier C1 and do not rotate integrally with the third sun gear S3. Thus, in the above embodiment, the piston 34 and the piston support member 35 are excluded from the rotating parts group that rotates integrally with the third sun gear S3. Compared to the comparative example shown in FIG. 7, which rotates integrally with S3', the mass of the rotating parts group can be further reduced, and the speed change responsiveness can be effectively improved.

Further, in the above embodiment, the piston 54 of the third clutch CL3 is a composite piston in which two relatively rotatable piston parts (main piston 54a and sub-piston 54b) are combined. Unlike the two clutches CL1, CL2, the centrifugal balance chamber can be omitted. That is, the piston 54 of the third clutch CL3 includes a sub-piston 54b that is supported by the partition wall portion 112 of the transmission case 11 and defines an engagement hydraulic chamber 58 between the partition wall portion 112 and the sub-piston 54b in the axial direction. and a rotatable main piston 54a for pressing the friction plate 53, and a bearing 54c for relatively rotatably connecting the main piston 54a and the sub-piston 54b. In this case, the members (the partition wall portion 112 and the sub-piston 54 b ) forming the engagement hydraulic chamber 58 do not rotate, and no centrifugal force acts on the engagement hydraulic chamber 58 . This means that the centrifugal balance chamber, which is a hydraulic chamber for canceling the influence of the centrifugal force, can be omitted. That is, there is no need to provide chambers corresponding to the centrifugal balance chambers 39, 49 for the other clutches CL1, CL2 at positions facing the engagement hydraulic chamber 58 with the piston 54 (main piston 54a) interposed therebetween. Therefore, it is possible to simplify the structure of the hydraulic supply system while ensuring the controllability of the piston 54 by the hydraulic pressure supplied to the engagement hydraulic chamber 58 .

Further, in the above embodiment, the drum member 51 of the third clutch CL3 is provided with the comb-shaped inner projections 51c, and the main piston 54a of the piston 54 is formed with the openings h2 through which the inner projections 51c are inserted. The inner projection 51c is coupled to the power transmission member 22 while passing through the main piston 54a. According to such a configuration, the pressing portion 54a1 of the main piston 54a is arranged inside the drum member 51 so that the friction plate 53 can be pressed by the pressing portion 54a1. can be connected to the third sun gear S3.

Further, in the above-described embodiment, the return spring 57 of the third clutch CL3 is arranged radially inside the friction plate 53 so as to overlap the friction plate 53 when viewed in the radial direction. According to such a configuration, the axial dimension of the third clutch CL3 can be shortened, and the automatic transmission 1 can be made compact in the axial direction.

Further, in the above-described embodiment, the return spring 57 is arranged at a position facing the bearing 54c with the main piston 54a interposed therebetween. According to this configuration, the bearing 54c that pushes the main piston 54a forward (in the tightening direction) and the return spring 57 that pushes the main piston 54a backward (in the release direction) face each other in the axial direction, realizing a rational arrangement. can do.

[Modification]
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, in the above embodiment, the hub members of the first clutch CL1 and the second clutch CL2 are shared by the common hub member 32. However, dedicated hub members may be prepared for the first clutch CL1 and the second clutch CL2. good too.

In the above embodiment, the two gear sets consisting of the first gear set PG1 and the second gear set PG2 are arranged between the first and second clutches CL1, CL2 and the third clutch CL3. , CL2 and the third clutch CL3 are not limited to two, and may be one or three or more.

In the above embodiment, a double sun gear type planetary gear set in which the sun gear S1 is axially divided into two is used as the first gear set PG1. A similar gearset (ie, a conventional type gearset in which the sun gear is not axially split) may be used.

In the above embodiment, an example in which the present invention is applied to a longitudinal automatic transmission mounted on an FR (front-engine, rear-drive) vehicle has been described. The present invention is not limited to a vertical type automatic transmission, and can be applied to a horizontal type automatic transmission mounted on a FF type (front engine/front drive type) vehicle.

1 Automatic Transmission CL1 First Clutch CL2 Second Clutch CL3 Third Clutch PG1 First Planetary Gear Set (Intermediate Planetary Gear Set)
PG2 2nd planetary gear set (intermediate planetary gear set)
PG3 3rd planetary gear set (outer planetary gear set)
S3 third sun gear (common rotating element)
21 power transmission member (first connecting member)
22 power transmission member (second connecting member; downstream connecting member)
32 common hub member (hub member of first clutch and second clutch)
33 (First clutch) Friction plate 43 (Second clutch) Friction plate 51 (Third clutch) Drum member 51a Peripheral wall portion 51b Vertical wall portion 51c Inner protrusion 53 (Third clutch) Friction plate 54 (Third Clutch) piston 54a Main piston 54a1 Pressing portion 54b Sub-piston 54c Bearing 57 Return spring 58 Engagement hydraulic chamber h2 (Piston) opening

Claims (6)

a first clutch and a second clutch arranged in the axial direction;
a third clutch disposed on one side of the first and second clutches in the axial direction;
an intermediate planetary gear set disposed between the first and second clutches and the third clutch;
an outer planetary gear set arranged on one axial side of the third clutch;
and a connecting member that connects the first clutch, the second clutch, and the third clutch to a common rotating element provided in the outer planetary gear set. In the automatic transmission according to claim 1,
each of the first clutch and the second clutch includes a plurality of friction plates arranged in an axial direction and a tubular hub member engaged with inner peripheral edges of the friction plates;
The third clutch includes a plurality of friction plates arranged in the axial direction and a cylindrical drum member engaged with the outer peripheral edges of the friction plates,
The connecting members include: a first connecting member connecting the hub members of the first and second clutches and the drum member of the third clutch; and connecting the drum member of the third clutch to the common rotating element. and a second connecting member that connects. In the automatic transmission according to claim 1,
The third clutch includes a plurality of friction plates arranged in the axial direction, a cylindrical drum member engaged with outer peripheral edges of the friction plates, and a piston axially pressing the friction plates,
The piston includes a sub-piston supported by the transmission case and defining an engagement hydraulic chamber with the transmission case, and a rotatable sub-piston axially opposed to the sub-piston and pressing the friction plate. An automatic transmission comprising: a main piston; and a bearing that couples the sub-piston and the main piston so that they can rotate relative to each other. In the automatic transmission according to claim 3,
The drum member includes a peripheral wall portion that extends axially on the radially outer side of the friction plate and engages with the outer peripheral edge of the friction plate, and a vertical wall portion that extends radially inward from one axial end of the peripheral wall portion. , a plurality of inner projections extending from the radially inner end of the vertical wall portion to the other side in the axial direction,
The main piston has a pressing portion that presses the friction plate, and a plurality of openings that are formed radially inward of the pressing portion and through which the inner projections are inserted,
The automatic transmission, wherein the connecting member includes a downstream side connecting member that connects the other axial end of the inner protrusion and the common rotating element. The automatic transmission according to claim 3 or 4,
The third clutch includes a return spring on the other side of the main piston in the axial direction for urging the main piston in a release direction for releasing pressure from the friction plates,
The automatic transmission according to claim 1, wherein the return spring is arranged radially inside the friction plates so as to overlap the friction plates when viewed in the radial direction. In the automatic transmission according to claim 5,
The automatic transmission according to claim 1, wherein the return spring is arranged at a position facing the bearing with the main piston interposed therebetween.

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