JPH07224911A - Automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To miniaturize an automatic transmission for vehicle and reduce its weight by shortening the length in the axial direction between an engine and a counter gear of the automatic transmission. CONSTITUTION:A friction engaging section 408 of a fourth brake B214 and a piston pressing mechanism section 412 are separated each other and arranged on both sides in the axial direction of a counter (driven) gear 231a so that a piston 410 of the fourth brake B214 is across the counter gear. The piston 410 is provided with a knotched section in a part which corresponds to a mesh section of the counter gear in the peripheral direction relative to the axis of the piston 410. On the other hand, a bent section is formed at an end of a contact separator plate 404a, and the bent section is engaged with the knotched section in the peripheral direction of the piston 410. As a result, rotation around the axis is prevented. Also, interference between the piston 410 and the counter gear is prevented because rotation around the axis of the piston 410 is prevented due to this composition, although the piston 410 is across the counter gear.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission for a vehicle, and more particularly to an automatic transmission for a vehicle which is further reduced in size and weight.

[0002]

2. Description of the Related Art Conventionally, from the viewpoint of downsizing and weight reduction of an automatic transmission, a method of arranging the counter gear near the engine and shortening the counter shaft has been widely used (Japanese Patent Laid-Open No. HEI 2). 168064).

However, in reality, due to the structure of the gear train, it is often necessary to dispose many brakes or clutches such as a one-way clutch between the engine and the counter gear. So these brakes,
Or while arranging a lot of clutches etc. and shortening the axial dimension between the engine and the counter gear,
There is no choice but to adopt a method of stacking the brakes and clutches in the radial direction.

However, in the method of stacking in the radial direction, when the number of stacks increases, the size in the radial direction inevitably increases, and the peripheral speed increases, so that the load on the friction surface increases correspondingly, and wear occurs. However, there is a problem that problems such as image sticking are likely to occur.

As one means for solving such a problem, US Pat. No. 5,194,056 proposes a structure in which a counter gear is arranged between a piston pressing mechanism portion and a friction engagement portion of a specific brake. That is, the frictional engagement portion composed of the separator plate and the friction plate of this particular brake device is arranged between the engine and the counter gear, and the piston pressing mechanism portion of the brake device is arranged on the counter engine side of the counter gear. However, as a result, a configuration is proposed in which the piston of the brake device is arranged in a state of straddling the counter gear.

In this structure, the friction engagement portion of the brake device and the piston pressing mechanism portion are separately arranged in the small dead spaces on both sides of the counter gear, and the space can be effectively used accordingly. It is expected to be able to be achieved.

[0007]

However, when the frictional engagement portion and the piston pressing mechanism portion of the brake device are arranged on both sides (in the axial direction) of the counter gear as described above, if the piston is located at the center of the counter gear. If the piston rotates around the shaft, there is a problem that the piston interferes with the counter gear (in particular, the counter driven gear).

However, the above-mentioned US Pat.
Then, no disclosure is made regarding this defect.

The present invention has been made in view of such a conventional problem, and in an automatic transmission having a brake device which is arranged so as to straddle a counter gear, the brake device and the counter driven gear are provided. It is an object of the present invention to provide an automatic transmission for a vehicle, which is capable of reliably preventing interference in structure and thereby realizing a reduction in size or weight of the automatic transmission without any trouble.

[0010]

According to a first aspect of the present invention, there is provided a brake device for selectively fixing a specific rotating member of a planetary gear mechanism to a housing, and a separator plate and a friction plate of the brake device. The friction engagement portion consisting of is arranged between the engine and the counter gear, and the piston pressing mechanism portion of this brake device is arranged on the side opposite to the engine side of the counter gear, whereby the piston of the brake device is In an automatic transmission for a vehicle arranged in a state of straddling the counter gear,
The piston rotation preventing mechanism for preventing rotation of the piston around the shaft is provided, and the piston has a notch in a portion corresponding to the meshing portion of the counter gear in the circumferential direction with respect to the shaft, thereby providing the above-mentioned object. It has been resolved.

According to a second aspect of the present invention, the piston detent mechanism has a substantially U-shape in which a portion of the separator plate that is in contact with the end surface of the piston has a portion corresponding to a notch of the piston. The above-mentioned problem is also solved by adopting a configuration such that both ends of the U-shape are bent toward the piston and the bent portions are engaged with the notches of the piston.

According to a third aspect of the present invention, the piston detent mechanism has a return spring for pushing the piston back from the separator plate side to the piston pressing mechanism side by a holding member in the circumferential direction with respect to the piston. The above-mentioned problem is also solved by the structure in which the holding member is held so as not to be relatively rotatable and the holding member is fixed to the housing.

[0013]

In the present invention, the piston rotation stopping mechanism for preventing the rotation of the piston of the brake device about the shaft is positively provided, and the piston has a meshing portion of the counter gear in the circumferential direction with respect to the shaft, that is, a counter drive. A notch is provided in the portion corresponding to the meshing portion of the gear and the counter driven gear.

As a result, there is no risk of the piston rotating around the shaft, and since there is a notch in the meshing portion of the counter gear, there is no risk of the piston interfering with the counter driven gear.

Therefore, it is possible to adopt a structure in which the friction engagement portion of the brake device and the piston pressing mechanism portion are separately arranged on both sides of the counter gear without any trouble. The size and weight can be reduced.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 2 shows a skeleton of an automatic transmission according to an embodiment of the present invention, and FIG. 1 shows a specific enlarged cross section of a main part.

In this embodiment, the first planetary gear mechanism 211 is constituted by a single pinion type planetary gear mechanism, and the second planetary gear mechanism 221 is constituted by a double pinion type planetary gear mechanism.

The first planetary gear mechanism 211 includes a sun gear S2.
11, a ring gear R211, and a carrier C201 holding a pinion gear P211 meshing with these are used as rotating elements.

On the other hand, in the second planetary gear mechanism 221, between the sun gear S221 and the ring gear R221, the short pinion gear PS221 meshing with the sun gear S221 is provided.
And a pinion gear P221 that meshes with the short pinion gear PS221 and the ring gear R221. The pinion gear P221 is integrated with the pinion gear P211 of the first planetary gear mechanism 211 to form a long pinion. Further, the carrier C201 of the first planetary gear mechanism 211 and the second planetary gear mechanism 221 is shared. In addition, the counter drive gear 231a which is an output member
Is the ring gear R22 in the second planetary gear mechanism 221.
1 is connected to the output shaft 280 that is integrally connected.

The input shaft 241 has a carrier C201 and a second
It is selectively coupled to the sun gear S221 of the planetary gear mechanism 221. An input shaft 241 as a friction engagement device therefor
The first clutch K211 is provided between the carrier and the carrier C201.

Further, the sun gear S of the first planetary gear mechanism 211.
A second clutch K212 and a first one-way clutch F211 arranged in series with each other are arranged between the 211 and the ring gear R211.

Further, a third clutch K213 is provided between the input shaft 241 and the sun gear S221 to secure an engine brake at the third speed and a reverse range.

On the other hand, as braking means, the first brake B is connected in series with the second clutch K212 between the sun gear S211 of the first planetary gear mechanism 211 and the housing 251.
211 is provided. The member of the first brake B211 on the clutch side is the first via the one-way clutch F211.
It is connected to the ring gear R211 of the planetary gear mechanism 211. This ring gear R211 is used for the third brake B213.
It is connected to the casing 251 via.

Further, the sun gear S2 of the second planetary gear mechanism 221.
21 and the housing 251 have a second brake B21.
Two are provided.

A fourth brake B214 and a second one-way clutch F212, which are arranged in series with each other, are arranged in parallel with the second brake B212.

The second one-way clutch F212
Are set to engage when the sun gear S221 tries to rotate in the reverse direction.

FIG. 3 is an operation table of each friction engagement device of the automatic transmission shown in FIGS. 1 and 2. Hereinafter, each shift speed will be described.

First, the first speed is set by engaging the first one-way clutch F211 with the engagement of the first clutch K211 and the first brake B211. That is, when the carrier C201 rotates together with the input shaft 241, the load on the output side is applied to the ring gear R221 of the second planetary gear mechanism 221.
The eleventh ring gear R211 tries to rotate in the reverse direction, but when torque in the reverse rotation direction is applied to the ring gear R211, the first one-way clutch F211 is engaged. As a result, the rotation of the ring gear R211 is blocked (that is, the ring gear R2
11 is given a reaction torque), and the ring gear R221 of the second planetary gear mechanism 221 which is an output member is input to the input shaft 241.
The speed is greatly reduced with respect to normal rotation.

The gear ratio at the first speed is such that the gear ratio of the first planetary gear mechanism 211 is ρ12, the gear ratio of the second planetary gear mechanism 221 is ρ22, and the pinion gear and ring gear on the outer peripheral side of the second planetary gear mechanism 221 are the same. When the tooth number ratio is γ22, it is represented by (1-ρ12) / (1-ρ12-2 · γ22) (1).

In order to activate the engine braking at the first speed, the third brake B213 provided in parallel with the first one-way clutch F211 is engaged, so that the first one-way clutch F211 runs in the idling direction. Ring gear R211
Prevent the rotation of.

On the other hand, in the 2nd speed, the second clutch is engaged with the first clutch K211 and the fourth brake B214.
It is set by engaging the one-way clutch F212 and idling the first one-way clutch F211. That is, when the carrier C201 rotates together with the input shaft 241, a load on the output side is applied to the ring gear R221 of the second planetary gear mechanism 221 and the sun gear S221 tries to rotate in the reverse direction. S221 is fixed (reaction torque is applied to the sun gear S221), and as a result, the ring gear R221, which is an output member, rotates the input shaft 241 to rotate the second planetary gear mechanism 2
It rotates forward at the rotation speed connected at 21. Therefore, this second
The speed change ratio is represented by 1 / (1-ρ22) (2). In this case, the first one-way clutch F2
11 changes from the engagement state up to that point to the idling state, and allows the normal rotation of the ring gear R211 of the first planetary gear mechanism 211.

The second speed is the second one-way clutch F212.
In order to prevent the rotation of the sun gear S221 in the idling direction of the second one-way clutch F212 when the engine brake is applied,
The second brake B212 is engaged.

In the third speed, the first clutch K211 and the second clutch
It is set by engaging the first one-way clutch F211 again as the clutch K212 is engaged. That is, by engaging the second clutch K212,
The sun gear S211 of the planetary gear mechanism 211 is rotated normally, and the first one-way clutch F211 is engaged. As a result, in the first planetary gear mechanism 211, the carrier C201, the sun gear S211, and the ring gear R211 rotate together with the input shaft 241. The whole rotates together. Therefore, the ring gear R221, which is an output member, rotates forward at the same speed as the input shaft 241 and is in a direct connection stage having a gear ratio of "1".

In this case also, the first one-way clutch F
Since 211 is engaged, the third clutch K213 is engaged when the engine brake is applied. or,
The second one-way clutch F212 is connected to the second one-way clutch F212.
The sun gear S221 of the planetary gear mechanism 221 is in the idling state until it normally rotates at the third speed. Therefore, even if the fourth brake B214 is engaged at the third speed, the fourth brake B21 is engaged.
4 is not involved in power transmission. Therefore, the fourth brake B
Since gear 214 does not need to be released in synchronization for gear shifting, gear shifting from the second speed to the third speed is performed by the second clutch K212.
Can be achieved only by newly engaging.

The fourth speed is set by engaging the first clutch K211, the second clutch K212, and the first brake B211. That is, since the carrier C201 is shared by the first planetary gear mechanism 211 and the second planetary gear mechanism 221, the carrier C201 is the same as the carrier C201.
When it rotates together with the first planetary gear mechanism 211,
The sun gear S211 fixed by the brake B211 and the second clutch K212 receives the reaction torque, and as a result, the common carrier C201 rotates forward around the sun gear S221, and the ring gear R221 of the second planetary gear mechanism 221 moves. It is added to the input shaft 241 and rotates normally. That is, an overdrive stage having a gear ratio smaller than "1" is achieved. The gear ratio in this case is represented by (1-ρ12) / (1-ρ12 + 2 · ρ12 · γ22) (3).

In this case, the sun gear S221 of the second planetary gear mechanism 221 rotates forward faster than the input shaft 241. Therefore, even if the fourth brake B214 is engaged, the one-way clutches F211 and F212 idle. Therefore, the fourth brake B214 does not participate in power transmission. Therefore, the third
The speed change from the fourth speed to the fourth speed can be achieved only by newly engaging the first brake B211 and a smooth speed change is possible.

On the other hand, the reverse speed is set by engaging the third clutch K213 and the third brake B213. That is, the sun gear S221 of the second planetary gear mechanism 221.
Is rotated together with the input shaft 241, a load on the output side is applied to the common carrier C201, and the pinion gear P211 of the first planetary gear mechanism 211 is a long pinion. Although the ring gear R211 of 211 is about to rotate in the forward direction, it is fixed by the brake B211 and receives reaction torque, and as a result, the ring gear R221 of the second planetary gear mechanism 221 rotates in the reverse direction. The gear ratio in this case is represented by (2 · γ22−ρ22 + ρ12 · ρ22) / (ρ22−ρ12 · ρ22-2 · ρ22 · γ22) (4).

FIG. 1 shows an enlarged cross section of the main part near the fourth brake B214. In addition, FIG. 4 is a view IV-IV of FIG.
It is sectional drawing which follows the line. In addition, in the cross section of FIG.
The detailed configuration of the central portion in the radial direction has no relation to the gist of the present invention, and is therefore omitted.

The fourth brake B214 is a sun gear S22.
Support shaft 278 and housing 2 connected to
51 is selectively connected via a second one-way clutch F212. The fourth brake B214 includes a clutch hub 402 which also serves as an outer race F212a of the second one-way clutch F212, a friction engaging portion 408 including a separator plate 404 and a friction plate 406.
And a piston 410, a piston pressing mechanism portion 412, and a return spring 416.

First, the first embodiment will be described.

FIG. 4 shows the counter gear 231 and the piston 4
The positional relationship with 10 is shown. The counter gear 231 includes a counter drive gear 231a and a counter driven gear 23.
1b, and they mesh with each other at the portion indicated by the arrow X.
The piston 410 is located on the outer diameter side of the counter drive gear 231a, and a notch 410a is formed in a portion corresponding to the meshing portion X between the counter drive gear 231a and the counter driven gear 231b, and the whole is substantially U-shaped.

As is apparent from FIGS. 1 and 4, the fourth brake B214 has its frictional engagement portion 408 disposed between the engine E and the counter gear 231, while the piston pressing mechanism mechanism portion 412 includes the caulder gear. 231 is arranged on the side opposite to the engine, and the piston 410 is arranged so as to straddle the counter gear 231.

On the other hand, the piston pressing mechanism portion 412 does not have a notch portion but exists over the entire circumference,
The overall shape is a donut shape.

5 and 6 show an example of the shape of the separator plate 404a among the plurality of separator plates 404 which comes into contact with the end surface 410b of the piston 410 when the brake is engaged. This contact separator plate 404
Like the other separator plate 404, a is non-rotatably fixed to the housing 251 of the automatic transmission by the spline 404a1. The contact separator plate 404a has a substantially U-shape similar to the piston 410, and its end portion is bent toward the piston 410 side, and the bent portion 404a2 engages with the notch portion 410a of the piston 410. It is configured to do.

The fourth brake B214 is, as described above,
Since the piston pressing mechanism portion 412 is arranged on the rear side (counter engine side) of the counter gear 231, the dead space can be effectively used, and the dead space between the counter gear 231 and the engine can be effectively increased without increasing the outer size. It is possible to shorten the distance.

Further, the piston 410 shaped so as to straddle the counter gear 231 will interfere with the counter driven gear 231b if it rotates about the central axis.
By the bent portion 404a2 provided on the contact separator plate 404a, the rotation around the axial direction is blocked,
In addition, since the contact separator plate 404a itself is non-rotatably fixed to the housing 251, the rotation of the piston 410 around the central axis is structurally prevented. Therefore, interference with the counter driven gear 231b cannot occur.

Also, this contact separator plate 404a
Can be easily and accurately manufactured by further bending the other separator plates 404, so that the rotation stopping mechanism of the piston 410 can be realized with almost no increase in cost.

Next, the second embodiment of the present invention will be described with reference to FIGS. 7 and 8.
An example will be described.

In this embodiment, the return spring 41 serves to push back the piston 410 when the brake is released.
6, a spline 418a is provided on the outer periphery of a spring seat (holding member) 418 that holds the housing 6, and
It is fixed so that it cannot rotate relative to 1. The spring seat 418 has a plurality of engagement holes 418b formed on a specific circumference thereof (in the illustrated example, on the circumference of the circumference on which the return spring 416 is arranged). The piston 410 is formed with a protrusion 410b which is inserted into and engaged with the engagement hole 418b at a portion indicated by Y in FIG. By adopting such a configuration, even if the piston 410 tries to rotate around the central axis, the piston 410 is rotated by the engagement between the engagement hole 418b of the spring seat 418 and the protrusion 410b of the piston 410. Rotation about the axis is prevented, and further, since the spring seat 418 is non-rotatably attached to the housing 251 via the spline 418a, it is possible to structurally prevent the rotation of the piston 410 about the axis. become able to.

That is, in this case, the spring seat 418
Of the projection 41 of the piston 410 by the engagement hole 418b of the
The configuration in which 0b is guided corresponds to a "piston rotation stop mechanism that prevents rotation of the piston 410 around its axis."

Although the illustrated automatic transmission employs both the first and second embodiments of the present invention, it goes without saying that only one of them can fulfill the function of preventing the piston from rotating.

[0053]

As described above, according to the present invention, the specific braking device is arranged separately on both sides in the axial direction of the counter gear, and the dead space in the automatic transmission is effectively utilized, resulting in the counter. The axial length between the gear and the engine can be shortened (without increasing the outer diameter), and the entire automatic transmission can be made smaller and lighter. While adopting it, it is possible to structurally prevent the piston from rotating around the shaft, so in combination with the presence of the notch in the piston,
An excellent effect is obtained in that it is possible to reliably prevent the piston and the counter gear from interfering with each other.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part showing the vicinity of a fourth brake of an automatic transmission for a vehicle according to the present invention.

FIG. 2 is a skeleton diagram showing the overall configuration of the vehicle automatic transmission.

FIG. 3 is a diagram showing an engagement state of each friction engagement element of the automatic transmission.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5 is a front view showing a configuration of a contact separator plate of a fourth brake of the automatic transmission.

6 is a sectional view taken along line VI-VI in FIG.

FIG. 7 is a front view showing a configuration of a return spring of the automatic transmission.

8 is a sectional view taken along the line VIII-VIII in FIG.

[Explanation of symbols]

 231 ... Counter gear 231a ... Counter drive gear 231b ... Counter driven gear B214 ... Fourth brake 402 ... Clutch hub 404 ... Separator plate 404a ... Abutment separator plate 404a1 ... Spline 404a2 ... Bent portion 406 ... Friction plate 408 ... Friction engaging portion 410 ... Piston 410a ... Notch portion 410b ... Protrusion portion 412 ... Piston pressing mechanism portion 416 ... Return spring 418 ... Spring seat 418a ... Spline 418b ... Engagement hole

Claims (3)

[Claims] 1. A brake device for selectively fixing a specific rotating member of a planetary gear mechanism to a housing, wherein a frictional engagement portion composed of a separator plate and a friction plate of the brake device connects an engine and a counter gear. For a vehicle in which the piston of the brake device is arranged in the state in which the piston of the brake device straddles the counter gear, by disposing the piston pressing mechanism portion of the brake device on the side opposite to the engine of the counter gear. In the automatic transmission, a piston anti-rotation mechanism that prevents rotation of the piston around the shaft is provided, and the piston is provided with a notch in a portion corresponding to the meshing portion of the counter gear in the circumferential direction with respect to the shaft. An automatic transmission for vehicles characterized by. 2. The piston rotation preventing mechanism according to claim 1, wherein the separator plate of the separator plate that comes into contact with the end face of the piston has a substantially U shape in which a portion corresponding to a notch of the piston is cut off. And bend both ends of the U-shape to the piston side,
The automatic transmission for a vehicle, wherein the bent portion is configured to engage with the notch of the piston. 3. The return spring for pushing back the piston from the separator plate side to the piston pressing mechanism portion side in the piston rotation preventing mechanism relative to the piston in the circumferential direction according to claim 1. An automatic transmission for a vehicle, which is configured to be held non-rotatably and to be fixed to a housing.