JPH07269661A - Automatic transmission - Google Patents

Abstract

PURPOSE:To axially shorten the size of an automatic transmission by reducing the diameter of an operational piston of a high speed stage fastening frictional element received in a drum constituting a power transmitting path of a planetary gear mechanism and effectively utilizing a recessed portion formed in the drum in the operational piston receiving portion to dispose a return spring for the operational piston of the other frictional element. CONSTITUTION:Third-fourth clutches 16 are provided inside the tip part of the opened side of a first drum 40 and a reverse clutch 18 is provided outside the intermediate part. A first piston 50 of the 3-4 clutches 16 is slidably fitted inside a recessed portion 40b formed in the bottom 40a side end of the first drum 40. A second piston 52 of the reverse clutch 18 is slidably fitted inside the bottom 42a side of a second drum 42. A return spring 52b of the second piston 52 is located in the outer peripheral part of the bottom 40a side end of the first drum 40 to dispose the inner peripheral part in the recessed portion 40b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention, by switching the power transmission path of a planetary gear mechanism through a plurality of friction elements,
The present invention relates to an automatic transmission that can obtain a plurality of shift speeds.

[0002]

2. Description of the Related Art An automatic transmission of this type is disclosed in, for example, Japanese Unexamined Patent Publication No. 2-113151 (F16H3 / 66). This automatic transmission is provided with a ring gear of a planetary gear mechanism and a clutch C1 on the inside of the open end of a bottomed cylindrical drum connected to the output shaft, and a clutch C0 on the outside of the bottom end of this drum. It is designed to be used. Therefore, by providing the two clutches C1 and C0 on one drum in this way, it is possible to reduce the number of parts of the automatic transmission and achieve compactness.

By the way, F. Since the automatic transmission applied to the F car is placed horizontally, it is desirable that the axial length thereof be further shortened to facilitate the layout in the engine room. The working piston of the clutch C1 is housed inside the bottom end of the drum, and the working piston of the clutch C0 is arranged axially outward of the bottom.

[0004]

However, in such a conventional automatic transmission, the working piston of the clutch C0 is provided axially laterally of the bottom portion of the drum, and the return spring of the working piston is provided at the bottom portion of the drum. It is supposed to be placed between and. Therefore, there is a problem that a space for disposing the return spring is required between the working piston and the drum bottom portion, and this space greatly restricts the reduction of the axial length of the automatic transmission. .

On the other hand, in various clutches for switching the power transmission path of the planetary gear mechanism, the torque acting on the clutch for high speed stage switching is relatively small. Therefore, the operating piston for operating this high speed stage switching clutch is It can be done with a small diameter.

In view of the conventional problems, the present invention reduces the diameter of the working piston of the friction element for high-speed stage engagement housed in the drum forming the power transmission path of the planetary gear mechanism, and houses the working piston. It is an object of the present invention to provide an automatic transmission in which a return spring of a working piston of another friction element is arranged and axially shortened by effectively utilizing a recessed portion formed in a drum of the portion.

[0007]

In order to achieve the above object, the present invention comprises a plurality of friction elements for switching the power transmission path of the planetary gear mechanism, and a plurality of gears can be shifted by appropriately switching these friction elements. In the automatic transmission described above, one of the plurality of friction elements is provided with a first friction element for switching between high speed stages and a second friction element different from the first friction element, which is commonly provided. The part is constituted by a bottomed cylindrical drum, the first friction element is arranged inside the open end of the drum, and the working piston of the first friction element is housed inside the bottom side of the drum, Further, while the second friction element is arranged outside the middle portion of the drum, the diameter of the working piston housing portion of the drum is reduced to reduce the diameter of the working piston, and the recessed portion is located outside the bottom side of the drum. Forming , Constructed by placing the return spring of the hydraulic piston of the second friction element to the recessed portion.

Further, it is desirable that a third friction element other than the first and second friction elements is arranged inside the drum.

Further, it is preferable that the first friction element is arranged on an outer peripheral portion of the planetary gear mechanism so as to overlap each other in the axial direction.

[0010]

In the automatic transmission according to the present invention having the above-described structure, the first friction element is arranged inside the open end of the drum which constitutes a part of the power transmission path of the planetary gear mechanism, and the drum is provided. By arranging the second friction element on the outer side of the intermediate portion of the drum, the drum can be shared by the first and second friction elements, so that the number of parts can be reduced and the axial length can be shortened. be able to. Also,
Since the first friction element is for high speed switching, it is possible to reduce the diameter of the working piston housed inward of the bottom side of the drum, and to form the recess formed when the outer side of the bottom side of the drum is reduced in diameter. Since the return spring of the working piston of the second friction element is arranged in the installed portion, it becomes possible to bring the working piston of the second friction element and the drum closer to each other in the axial direction. A reduction in axial length can be achieved.

Further, by disposing a third friction element other than the first and second friction elements inside the drum,
It is not necessary to provide a space for disposing the third friction element in the axial direction, and the axial length can be shortened accordingly.

Further, by disposing the first friction element on the outer peripheral portion of the planetary gear mechanism and overlapping each other in the axial direction, the drum as a whole can be brought closer to the planetary gear mechanism side, Accordingly, the axial length of the automatic transmission can be shortened.

[0013]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 1 and 2 show an embodiment of an automatic transmission 10 according to the present invention, FIG. 1 is a cross-sectional view showing a main part of the automatic transmission 10, and FIG. 2 shows a lower half from a central axis of the automatic transmission 10. It is a schematic block diagram which shows.

That is, as shown in FIG. 1, the gear train of the automatic transmission 10 according to this embodiment has a first planetary gear 12 as a gear train.
And a second planetary gear 14 are provided, and each of the power transmission paths of the first and second planetary gears 12, 14 has a 3-4 clutch 16, a first friction element, and a second planetary gear 14. 2 Reverse clutch as friction element 1
8, a forward clutch 20 as a third friction element,
Friction elements of the low-and-reverse brake 22 and the 2-4 brake 24, and a one-way clutch 26 are arranged. The engagement and disengagement of each of the friction elements is controlled by a control oil pressure supplied from a control valve (not shown), so that a shift speed corresponding to each operating condition such as vehicle speed and accelerator opening can be obtained. In addition, the above 3-
The four-clutch 16, the reverse clutch 18, the forward clutch 20, and the low-and-reverse brake 22 are each configured as a multi-plate clutch.
The brake 24 is configured as a band brake.

An engine (not shown) is arranged on the right side of the automatic transmission 10 in the figure, and the engine rotation is input to the input shaft 30 of the automatic transmission 10 via the torque converter 28. Is appropriately shifted by the gear train, and then output to the differential gear 36 via the output drive gear 32 and the output driven gear 34.

As shown in FIG. 2, the gear train has a path A which is connected to the sun gear 12a of the first planetary gear 12 and is connectable to the housing 38 via the 2-4 brake 24, and the reverse clutch 18 is connected. It is possible to connect to the path B connected to the input shaft 30 via. The path C connected to the pinion gear 12b of the first planetary gear 12 can be connected to the path B via the 3-4 clutch 16. Further, the ring gear 12c of the first planetary gear 12 is connected to the pinion gear 14b of the second planetary gear 14 via the path D.

On the other hand, the path E connected to the sun gear 14a of the second planetary gear 14 is the forward clutch 2
It is possible to connect to the path F connected to the input shaft 30 via 0. The pinion gear 14b of the second planetary gear 14 serves as an output element for variable speed rotation, and is connected to the output drive gear 32 via the path G. Further, the path H connected to the ring gear 14c of the second planetary gear 14 is connected to the pinion gear 12b of the first planetary gear 12 and can be connected to the housing 38 via the low and reverse brake 22. . At this time, the one-way clutch 26 is arranged between the ring gear 14c and the housing 38 in parallel with the low and reverse brake 22.

Further, the automatic transmission 10 of this embodiment provided with the gear train having the above-mentioned structure is provided with the forward clutch 20.
(FwdCL), 3-4 clutch 16 (3-4CL), reverse clutch 18 (RevCL), low and reverse brake 22 (L / RBr), 2-4 brake 24 (2-4Br), are shown in the following Table 1. By engaging and disengaging as described above, 1st (forward 1st speed), 2nd (forward 2nd speed), 3rd
(3rd forward speed), 4th (4th forward speed) and Rev (reverse speed) are available. In the table, ◯ indicates a fastened state and x indicates a released state. In addition, the table also shows the operating state of the one-way clutch (OWC).
L indicates a locked state and F indicates a free state.

[0019]

[Table 1] By the way, in the gear train, as shown in FIG. 1, the path B is formed by the first drum 40 and the path A is formed.
Is formed by the second drum 42, and the path F is formed by the third drum 44. The first, second and third drums 4
Each of 0, 42, and 44 is formed in a bottomed cylindrical shape, and the first drum 40 is interposed between the large-diameter second drum 42 and the small-diameter third drum 44 and arranged concentrically. It

The bottom portion 40 of the first and third drums 40 and 44
The central portions of a and 44a are fitted to the boss portion 46 that is integrally fixed to the input shaft 30, and the central portion of the bottom portion 42a of the second drum 42 is the collar portion 48 that is integrally fixed to the housing 38. It is rotatably fitted to the outer circumference. At this time,
The boss portion 46 is rotatably fitted on the outer periphery of the collar portion 48. Further, the collar portion 48 is formed with passages 48a, 48b, 48c for supplying hydraulic pressure to cylinder chambers 50a, 52a, 54a, which will be described later.

The outer peripheral wall of the first drum 40 is gradually reduced in diameter from the open side (left side in the figure) toward the bottom portion 40a, and the end portion where the bottom portion 40a is provided further has a recessed portion 40b. The diameter is greatly reduced. Then, the 3-4 clutch 16 is provided inside the open side front end portion of the first drum 40, and 3 inside the recessed portion 40b.
-4 First piston 50 that applies a fastening force to the clutch 16
Are slidably fitted.

The reverse clutch 18 is provided outside the middle portion of the first drum 40, and the second piston 52 that applies a fastening force to the reverse clutch 18 is provided inside the bottom portion 42a of the second drum 42. Are slidably fitted. Further, the forward clutch 20 is provided inside the opening side of the third drum 44,
A third piston 54 for engaging the forward clutch 20 is slidably fitted inside the bottom portion 44a of the third drum 44. The cylinder chamber 50 is provided between the first, second, and third pistons 50, 52, 54 and the drum bottoms 40a, 42a, 44a in which they are fitted.
a, 52a, 54a are formed, and these cylinder chambers 50
The control hydraulic pressure is supplied to the insides of a, 52a, 54a.

The 3-4 clutch 16 and the forward clutch 20 serve as a forward-stage engaging element. The cylinder chamber 50 is provided in each of the first and third pistons 50 and 54.
Centrifugal balance chambers 50c and 54c are configured by disposing annular partition plates 50b and 54b on the opposite side of a and 54a. Then, by the centrifugal pressure acting on the hydraulic oil filled in the centrifugal balance chambers 50c, 54c, the cylinder chambers 50a,
The centrifugal pressure that acts on the hydraulic oil in 54a is offset,
The four clutch 16 and the forward clutch 20 are prevented from being dragged.

The inner peripheral portion of one partition plate 50b is locked to the outer periphery of the boss portion 46 via a snap ring 56, and the other partition plate 54b is attached to the outer periphery of the input shaft 30 via a snap ring 58. Be locked. The snap ring 56 for locking the partition plate 50b is also used for locking the third drum 44, and the number of parts can be reduced.

By the way, the first, second and third pistons 50, 52 and 54 are respectively provided with return springs 50.
A return force at the time of releasing the hydraulic pressure is added by d, 52b and 54d. The return springs 50d and 52b of the first and second pistons 50 and 52 are diaphragms and the return spring 54d of the third piston 54 is a coil spring. Composed of.

Here, the return spring 52b of the second piston 52 formed of a diaphragm is located at the outer peripheral portion of the end portion of the first drum 40 on the bottom portion 40a side, and the inner peripheral portion of the return spring 52b of the first drum 40. It is arranged in the recessed portion 40b. The outer periphery of the return spring 52b is provided inside the second drum 42 and the reverse clutch 18 is provided.
While being locked to the snap ring 18a, the inner peripheral portion arranged in the recessed portion 40b is locked to the second piston 52.

With the above structure, the automatic transmission 1 of this embodiment
In 0, among the power transmission paths constituted by the first planetary gear 12 and the second planetary gear 14, the paths B, A and F are respectively the bottomed cylindrical first and second paths.
It is formed by the second and third drums 40, 42, 44, and the 3-4 clutch 16 for switching the high speed stage is provided inside the opening side front end portion of the first drum 40, and the river is provided outside the middle portion of the first drum 40. The scratch 18 is provided, and the third drum 44 is further provided.
The forward clutch 20 is provided on the inner side of the open side of the. Therefore, since the first drum 40 is shared as the power transmission path for the 3-4 clutch 16 and the reverse clutch 18, the number of parts can be reduced and the axial length of the automatic transmission 10 can be shortened. You can

Further, since the 3-4 clutch 16 is for switching the 3rd and 4th high speed stages, the torque acting on the 3-4 clutch 16 is relatively small, and therefore the 3-4 clutch 16 is engaged. In order to do so, the first piston 50 housed inside the first drum 40 on the side of the bottom portion 40a
It is possible to reduce the diameter. Therefore, the first piston 5
0 is housed inside the recessed portion 40b formed by reducing the diameter of the outer side of the first drum 40 on the side of the bottom portion 40a.
The return spring 52b of the second piston 52 for engaging the reverse clutch 18 is arranged at 0. Therefore, since the return spring 52b can be arranged in the recessed portion 40 located in the outer peripheral direction of the first drum 40 in this way, the second piston 52 and the first piston 52 housed inside the bottom portion 42a of the second drum 42 can be arranged.
The bottom portion 40a of the drum 40 can be brought closer to the axial direction, and the axial length of the automatic transmission 10 can be shortened accordingly.

The first, second and third drums 40,
42 and 44 are the third drum 44 and the first drum 4 from the inside.
0 and the second drum 42 are arranged concentrically in this order,
Since the forward clutch 20 is arranged on the third drum 44 located inside the first drum 40, a space for arranging the forward clutch 20 is provided in the first drum 4.
It is not necessary to provide it outside the axial direction of 0, and further, the axial length of the automatic transmission 10 can be further shortened.

3 and 4 show an automatic transmission 10 according to another embodiment.
The same reference numerals are given to the same components as those of the above-mentioned embodiment, and the duplicate description will be omitted. 3 is a cross-sectional view showing the main part of the automatic transmission 10a, and FIG. 4 is a schematic configuration diagram showing the lower half of the automatic transmission 10 from the central axis.

That is, the automatic transmission 10a of this embodiment is constructed by replacing the front and rear positions of the first planetary gear 12 and the second planetary gear 14 with respect to the automatic transmission 10 of the above embodiment. First, second, and third drums 40, 42, 4 arranged concentrically on paths B, A, F, respectively
No. 4, and the 3-4 clutch 16 is provided inside the open end of the first drum 40.
A reverse clutch 18 is provided outside the middle part of 0,
The forward clutch 20 is provided inside the opening side of the third drum 44.
Is provided. Further, each friction element provided in this embodiment, that is, the 3-4 clutch 16, the reverse clutch 18, the forward clutch 20, the low-and-reverse brake 22, and the 2-4 brake 24 are respectively arranged according to the engagement and release shown in Table 1 above. It is designed so that the shift speed can be obtained.

Here, in this embodiment, the front and rear positions of the first planetary gear 12 and the second planetary gear 14 are interchanged, so that the open-side end portion of the first drum 40 is changed to the second end.
It is possible to dispose on the outer peripheral portion of the planetary gear 14, and in this embodiment, the 3-4 clutch 16 provided inside the open side front end portion of the first drum 40 is provided on the outer peripheral portion of the second planetary gear 14. It is arranged.

Therefore, in this embodiment, the 3-4 clutch 1 is used.
By disposing 6 on the outer peripheral portion of the second planetary gear 14, the first drum 40 provided with the 3-4 clutch 16 and the second planetary gear 14 can be brought closer to each other in the axial direction, and the automatic transmission The axial length of 10a can be further shortened.

[0034]

As described above, according to the first aspect of the present invention.
In the automatic transmission shown in (1), since the first friction element is arranged inside the open end of the drum and the second friction element is arranged outside the middle portion of the drum, the number of parts can be reduced. At the same time, the axial length can be shortened. Further, since the first friction element for switching to the high speed stage is accommodated inside the bottom side of the drum, and the return spring of the second friction element is arranged in the recessed portion formed on the outside thereof, the second friction element is provided. The working piston of the element and the drum can be brought close to each other in the axial direction, and the axial length of the automatic transmission can be shortened accordingly, and the layout in a narrow engine room can be facilitated.

Further, according to the second aspect of the present invention, since the third friction element other than the first and second friction elements is arranged inside the drum, the axial arrangement of the third friction element is performed. It is not necessary to provide a space, and the axial length can be further shortened accordingly.

Further, according to a third aspect of the present invention, the first friction element is arranged on the outer peripheral portion of the planetary gear mechanism, and the first friction element and the first friction element are axially overlapped with each other. In addition, various advantageous effects can be achieved in that it can be brought closer to the planetary gear mechanism side, and the axial length of the automatic transmission can be further shortened accordingly.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an automatic transmission according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a lower half from a central axis of an automatic transmission showing an embodiment of the present invention.

FIG. 3 is a sectional view showing a main part of an automatic transmission according to another embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing a lower half from a central axis of an automatic transmission showing another embodiment of the present invention.

[Explanation of symbols]

10, 10a Automatic transmission 12 First planetary gear (planetary gear mechanism) 14 Second planetary gear (planetary gear mechanism) 16 3-4 Clutch (first friction element) 18 Reverse clutch (second friction element) 20 Forward Clutch (third friction element) 22 Low-and-reverse brake (friction element) 24 2-4 Brake (friction element) 26 One-way clutch 28 Torque converter 30 Input shaft 40 First drum 40a Bottom 40b Recessed portion 42 Second
Drum 42a Bottom 44 Third
Drum 44a Bottom part 50 First piston (operating piston of first friction element) 52 Second piston (operating piston of second friction element) 52b Return spring

Front Page Continuation (72) Inventor Tatsuhiko Iwasaki 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation

Claims (3)

[Claims] 1. An automatic transmission comprising a plurality of friction elements for switching a power transmission path of a planetary gear mechanism, wherein the friction elements are appropriately switched so that a plurality of gears can be shifted. A first friction element for switching to a high speed stage and a part of a power transmission path in which a second friction element different from the first friction element is provided in common are constituted by a bottomed cylindrical drum. Inside the tip end on the open side, the first
The friction element is arranged, the working piston of the first friction element is housed inward of the bottom side of the drum, and the second friction element is arranged outside the middle part of the drum, while the working piston of the drum is arranged. A diameter of the accommodating portion is reduced to reduce the diameter of the working piston, a recessed portion is formed on the outer side of the bottom side of the drum, and a return spring of the working piston of the second friction element is disposed in the recessed portion. Automatic transmission characterized by. 2. The automatic transmission according to claim 1, wherein a third friction element other than the first and second friction elements is arranged inside the drum. 3. The automatic transmission according to claim 1, wherein the first friction element is arranged on an outer peripheral portion of the planetary gear mechanism so as to overlap each other in the axial direction.