JPH022503B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a clutch device for an automatic transmission for an automobile. (Prior Art) If the vehicle is, for example, a front-engine, front-drive vehicle, it is advantageous to arrange the automatic transmission so that its center axis extends in the direction of the vehicle. However, since there are limits to vehicles, it is desirable that the axial length of the automatic transmission be as short as possible, and for this reason, various proposals have been made to shorten the axial length. For example, in JP-A-57-1848, the axial length of the clutch device is shortened by arranging two clutches one on top of the other in the radial direction instead of arranging them in parallel in the axial direction. The shaft length of the automatic transmission in which the clutch device is incorporated has been reduced. (Object of the Invention) An object of the present invention is to provide a clutch device for an automatic transmission for an automobile, which can always perform appropriate shifting timing, has a more compact structure, and has a shorter shaft length than conventional devices. This is the purpose. (Structure of the Invention) A clutch device for an automatic transmission for an automobile according to the present invention is provided on a turbine shaft of a torque converter, and includes a small sun gear, a large diameter sun gear disposed on the side of the small diameter sun gear, and a long pinion gear. and a Ravigneaux-type planetary gear unit consisting of short pinion gears, a carrier for holding these pinion gears, and a ring gear;
In order to fix the large-diameter sun gear of the Ravigneaux-type planetary gear unit, a drum having a predetermined width in the axial direction is disposed coaxially with the turbine shaft on the axial side of the planetary gear unit adjacent to the large-diameter sun gear. a drum brake consisting of a band hung on the drum; and a forward clutch device disposed radially inside the drum of the drum brake to connect and disconnect power transmission between the small-diameter sun gear and the turbine shaft via a one-way clutch. , a coasting clutch device disposed adjacent to the forward clutch device in the drum of the drum brake and configured to connect and disconnect power transmission between the small diameter sun gear and the turbine shaft in parallel with the forward clutch device; Located radially outside the brake drum,
and a reverse clutch device in which a clutch hub is formed in an extension of the front end of the drum of the drum brake in the axial direction, and that connects and disconnects power transmission between the large-diameter sun gear and the turbine shaft via the drum of the drum brake. In the forward and coasting clutch device, a clutch drum of the other clutch device is disposed radially inwardly of one of the clutch drums, and the clutch drum of the other clutch device also serves as the piston of the one clutch device and houses a piston for the other clutch device inside. The clutch device of one of the forward and coasting clutch devices and the reverse clutch device are arranged radially overlapping each other, and the clutch disk of the other clutch device of the forward and coasting clutch device and the one-way clutch are arranged radially overlapping at a position on the planetary gear unit side of the one clutch device, with the one-way clutch inside. (Effect of the invention) In the automatic transmission for automobiles having the above structure,
Since the reverse clutch requires fewer friction plates, the axial length can be shortened, and by installing it in parallel with a drum brake (the longer the axial length, the more reliable the operation), the axial length can be increased. This can be prevented and the operation of the brake can be ensured. Also, among the clutches placed inside the drum brake, the forward clutch has a longer axial length, but the coasting clutch, which is only connected during engine braking, can have a shorter axial length, so these two clutches can be By arranging them side by side, the axial length can be shortened by stacking them radially inside the drum brake and reverse clutch. In addition, the forward clutch and the coasting clutch overlap each other, the clutch disc of one of the forward and coasting clutches overlaps the one-way clutch in the radial direction, and the reverse clutch overlaps the other clutch in the radial direction. With the arrangement of placing the clutch disk and one-way clutch of the other clutch on the side, the clutch disk and one-way clutch of the one located radially outward of the forward clutch and coasting clutch, and the clutch and reverse clutch of the other clutch are placed radially outward. By stacking them on top of each other, dead space can be used effectively, making it more compact in the axial direction and in the radial direction. (Embodiments) Hereinafter, a clutch device for an automatic transmission for an automobile according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing an automatic transmission for an automobile incorporating a clutch device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 indicates a crankshaft of an engine (not shown) which is an input shaft, and a torque converter 2 and a multi-speed gearing device 10 are arranged coaxially with this crankshaft 1 in order from the engine side. . The torque converter 2 includes a pump 3, a turbine 4, and a stator 5,
The pump 3 is fixed to the crankshaft 1. The stator 5 is connected to a fixed shaft 7 integrally connected to the case 11 of the multi-speed gearing device 10 via a one-way clutch 6.
rotate on top. The one-way clutch 6 allows the stator 5 to rotate in the same direction as the pump 3, but does not allow it to rotate in the opposite direction. The multi-speed gear device 10 has a base end fixed to the crankshaft 1 and a distal end extending through the center of the multi-speed gear device to drive an oil pump P disposed on the side wall of the device. It has a central shaft 12 connected to the pump. On the outside of this central shaft 12, a hollow turbine whose base end is connected to the turbine 4 of the torque converter 2, whose distal end extends to the side wall of the multi-speed gear unit 10, and is rotatably supported by the side wall. A shaft 13 is provided. A Ravigneau type planetary gear unit 14 is provided on the turbine shaft 13, and this planetary gear unit 14 is connected to a small diameter sun gear 15, and a large diameter sun gear 1 disposed on the side of the small diameter sun gear 15 far from the engine.
6, a long pinion gear 17, a short pinion gear 18, and a ring gear 19.
A first clutch device 20, which is a forward clutch, and a second clutch device 21, which is a coasting clutch, are arranged in parallel on the side of the planetary gear unit 14 that is far from the engine. The first clutch device 20 connects and disconnects power transmission between the small diameter sun gear 15 and the turbine shaft 13 via the first one-way clutch 22. On the other hand, the second clutch device 21 is connected in parallel with the first clutch device 20 to connect and disconnect power transmission between the small sun gear 15 and the turbine shaft 13. A first brake device 23 is arranged radially outward of the second clutch device 21. The first brake device 23 is a drum brake, and includes a brake drum 23a connected to the large-diameter sun gear 16 and a brake band 23b wrapped around the brake drum. As is clear from the figure, the inside of this brake drum 23a, that is, this brake drum 23a and the turbine shaft 1
between the first and second clutch devices 2
0 and 21 are arranged to utilize the space inside the drum. Radially outward of the first clutch device 20 and to the side of the first brake device 23 is a reverse clutch. A third clutch device 24 is arranged, and this third clutch device 24 connects the large diameter sun gear 1 via the brake drum 23a of the first brake device 23.
6 and the turbine shaft 13. A carrier 14a of the planetary gear unit 14 and a case 10a of the multi-speed gear device 10 are arranged radially outwardly of the planetary gear unit 14.
A second brake device 25 is arranged to engage and disengage the. The first and second brake devices 23
and 25, a second one-way clutch device 26 is disposed in parallel with the second brake device 25 for engaging and disengaging the carrier 14a and the case 10a. On the side of the planetary gear unit 14 on the engine side, a carrier 14a of the planetary gear unit and the turbine shaft 13 are arranged.
a fourth clutch device 2 for intermittent power transmission between
7 is placed. This fourth clutch device 2
An output gear 28 connected to a ring gear 19 is arranged on the side of the engine 7 on the engine side. In addition, the reference numeral 29 in the figure indicates the turbine shaft 1.
3 shows a lock-up clutch for directly connecting the crankshaft 1 to the crankshaft 1 without going through the torque converter 2. Next, with reference to FIG. 2, the structure of each of the above-mentioned devices constituting the automatic transmission will be explained. Second Clutch Device 21 This second clutch device 21 includes a clutch drum 21b that is spline-coupled to the turbine shaft 13 and integrally supported by a support portion 21a having a substantially U-shaped cross section. A clutch hub 21c is located inside the clutch drum 21b.
This clutch hub 21c is connected to a support portion 2 splined to the small diameter sun gear 15.
It is integrally supported by 1d. The clutch drum 21b and the clutch hub 21c each support alternately arranged clutch disks 21e. A piston 21f, which has a shape corresponding to the contour of the inner wall of the support part 21 and has a substantially U-shaped cross section, is fitted inside the support part 21a.
A hydraulic oil chamber 21g is formed between the piston 21f and the support body 21a.
By controlling the supply of hydraulic oil to 1g,
The second clutch device 21 is engaged or disengaged by pushing or releasing the clutch disk 21e. As is clear from the figure, the base of the support portion 21d of the clutch hub 21c constitutes the inner race of the first one-way clutch 22. First clutch device 20 Piston 21f of the second clutch device 21
serves also as the clutch drum 20a of the first clutch device 20 and a support portion 20b that integrally supports the clutch drum 20a. A clutch hub 20c is disposed inside the clutch drum 20a, and the base of the clutch hub 20c is integrally supported by a support portion 20d that constitutes the outer race of the one-way clutch 22. The clutch drum 20a and the clutch hub 20c each support alternately arranged clutch disks 20e. A piston 20f is fitted inside the support portion 20b, and a hydraulic oil chamber 20g is formed between the piston 20f and the support portion 20b. By controlling the supply of hydraulic oil to the hydraulic oil chamber 20g, the clutch disk 20e is pushed or released, and the first clutch device 20 is engaged or disengaged. In addition, 20h in the figure is the first
and return springs for the pistons 20f, 21f of the second clutch devices 20, 21. Third clutch device 24 This third clutch device 24 is connected to the support portion 2.
A substantially inverted L-shaped support portion 24a that is integral with 1a.
clutch drum 24 integrally supported by
It is equipped with b. A clutch hub 24c is arranged inside and opposite the clutch drum 24b, and the clutch hub 24c is formed by an extension of the brake drum 23a of the first brake device 23. Clutch drum 24b and clutch hub 24c each support alternating brake discs 24d.
A piston 24e is fitted inside the support portion 24a, and the piston 24e and the support portion 24a
A hydraulic oil chamber 24f is formed between them. By controlling the supply of hydraulic oil to the hydraulic oil chamber 24f, the clutch disc 24d is pressed or released, and the third clutch device 20
It is designed to engage and disengage. This third clutch device 24 includes a diaphragm-type return spring 24 for the piston 24e.
It is equipped with g. The reason why a diaphragm type return spring is used in this third clutch device 24 is that this diaphragm type is thin and does not require a large space. Fourth Clutch Device 27 This fourth clutch device 27 is spline-coupled to the turbine shaft 13 and includes a clutch drum 27b that is integrally supported by a support portion 27a having a substantially inverted U-shaped cross section. There is. Inside this clutch drum 27b, a clutch hub 2
7c is arranged, and this clutch hub 27c
is the carrier 14 of the planetary gear unit 14
It is supported by a. The above clutch drum 27b
The clutch hubs 27c and 27c each support alternately arranged brake discs 27d. A piston 27e formed by sheet metal processing is fitted inside the support portion 27a. A hydraulic oil chamber 27 is located between the piston 27e and the support portion 27a.
By controlling the supply of hydraulic oil to the hydraulic oil chamber 27f, the clutch disc 27d is pressed or released.
The fourth clutch device 27 is engaged and disengaged. This fourth clutch is also provided with a diaphragm type return spring 27g, similar to the third clutch device 24 described above. First Brake Device 23 The brake drum 23a of the first brake device 23 is supported by a support portion 23c that is integrally supported by the large diameter sun gear 16. Therefore, when this first brake device 23 is activated,
The large diameter sun gear 16 is fixed. As shown in FIG. 3, the outer edge of the support portion 23c is offset toward the engine to increase the width of the drum 23a and expand the drum surface, thereby facilitating brake operation. It is made certain. Second brake device 25 This second brake device 25 is a disc type brake, and its brake drum 25a
is the carrier 14a of the planetary gear unit 14.
It is supported by a support portion 25b that is integrally fixed to the support portion 25b. Therefore, this second brake device 2
3 is activated, the carrier 14a is fixed. Functions of the multi-speed gear device 10 The multi-speed gear device 10 having the structure described above has the following features:
It has four forward speeds and one reverse speed.
First, second, third and fourth clutch devices 2
0, 21, 24 and 27, and the first and second brake devices 23 and 25, a desired gear stage can be obtained.
In the above configuration, the operational relationship between each gear stage, clutch, and brake is shown in the table below.

[Table] Hereinafter, the functions of the first and second one-way clutches 22 and 26 will be explained. Second one-way clutch 26 This one-way clutch 26 prevents the carrier 14a from reversing during 1st gear, and when shifting from 1 to 2 and from 2 to 2.
This serves to determine the shift timing during the first shift. As can be seen from the above table, the reverse rotation of the carrier 14a is prevented in 1st gear, and the carrier 14a is allowed to rotate forward in 2nd gear, and the large diameter sun gear 16
must be fixed. For this reason, 1-2
When changing gears, it is necessary to operate means for freeing the carrier 14 and means for fixing the large diameter sun gear 16, that is, the first brake device 23. If the means for freeing the carrier 14 is a band brake, the large diameter sun gear 16 must be fixed after first freeing the carrier 14a, resulting in a temporary neutral state and a time lag. On the other hand, when a one-way clutch is used as the above-mentioned means, as in this device, the carrier 14a becomes free and rotates forward at the moment the large-diameter sun gear 16 is fixed due to the action of the one-way clutch, so there is no time lag. It is possible to shift gears with good timing. Meanwhile, the carrier 14a rotates forward and the ring gear 1
If the carrier 14a is fixed when shifting from the 2nd gear state in which gear 9 is rotating at the 2nd gear speed, the rotation of the ring gear 19 will be lower by the rotation amount of the carrier 14a than when the ring gear 19 is in the 2nd gear. try to For this reason, the carrier 14 is
If a is fixed unconditionally and all at once, a shift shock will occur. In order to prevent this shift shock, it is sufficient to wait until the engine rotation increases to the first speed rotation or the vehicle speed decreases before shifting. However, timing the fixing of the carrier 14a and the release of the large-diameter sun gear 16 is extremely difficult if a band brake is used. In comparison, when a one-way clutch is used, the carrier 14a can continue to rotate at the second speed even after the large-diameter sun gear 16 is released, and only when it reaches the same speed as the ring gear 19 does the small-diameter sun gear 15 start moving. The driving force is now transmitted, and the 2-
It is possible to take the timing when shifting to 1st gear. First one-way clutch 22 This one-way clutch 22 functions to determine the shift timing when shifting from 3 to 4 and when shifting from 4 to 3. As can be seen from the above table, in 3rd gear, the clutch devices 21 and 27 are connected and rotate together, while in 4th gear, the clutch 21 is released and the small diameter sun gear 15 rotates at an increased speed, and the large diameter sun gear 16 needs to be fixed. Under these conditions 3→
When performing a 4-speed shift, if only a normal clutch is used, a neutral state is required temporarily, but if a one-way clutch is used, just by fixing the large diameter sun gear 16, the small diameter sun gear 15 will start increasing speed from that moment. Therefore, there is no time lag and the 3rd to 4th gear shift can be performed with accurate timing. On the other hand, in 4th gear, the small diameter sun gear 15 is rotating at an increased speed, so in order to shift from 4th gear to 3rd gear, the engine rotation speed (input rotation) must increase or
Alternatively, it is necessary to wait until the rotation (output rotation) of the ring gear 19 decreases before fixing the small diameter sun gear 15. It is difficult to obtain this timing with a normal clutch, but by using a one-way clutch, when the input rotation matches the rotation of the small diameter sun gear 15, the driving force from the input side can be automatically transmitted, resulting in a good timing. You can change gears at the right time.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram illustrating the basic configuration of an automatic automatic transmission incorporating a clutch device according to an embodiment of the present invention, and FIG. 2 is a structure of the multi-speed gear device and clutch device shown in FIG. 1. FIG. 3 is an enlarged sectional view of the clutch device shown in FIG. 2. 1...Crankshaft, 2...Torque converter,
10... Multi-speed gear device, 12... Central shaft, 1
3...Turbine shaft, 14...Planetary gear unit, 15...Small diameter sun gear, 16...Large diameter sun gear, 17...Long pinion gear, 18
... Short pinion gear, 19 ... Ring gear, 20 ... First clutch device, 21 ... Second clutch device, 22 ... First one-way clutch device, 23 ... First brake device, 23a
...Brake drum, 24...Third clutch device, 25...Second brake device, 26...Second one-way clutch, 27...Fourth clutch device, 28...Output gear.

Claims (1)

[Claims] 1 A small-diameter sun gear provided on the turbine shaft of a torque converter, a large-diameter sun gear disposed on the side of the small-diameter sun gear, a long pinion gear, a short pinion gear, a carrier for holding these pinion gears, and a ring gear. In order to fix the large-diameter sun gear of the Ravigneaux-type planetary gear unit, the shaft is disposed coaxially with respect to the turbine shaft on the axial side of the planetary gear unit adjacent to the large-diameter sun gear. A drum brake consisting of a drum having a predetermined width in the direction and a band hung on the drum, and a one-way clutch disposed inside the drum of the drum brake to transmit power between the small diameter sun gear and the turbine shaft. a forward clutch device disposed adjacent to the forward clutch device within the drum of the drum brake, and configured to connect and disconnect power transmission between the small diameter sun gear and the turbine shaft in parallel with the forward clutch device; a coasting clutch device; a clutch hub disposed radially outwardly of the drum of the drum brake; and a clutch hub formed in an extension of the tip of the drum of the drum brake in the axial direction; A reverse clutch device is provided for intermittent power transmission between the radial sun gear and the turbine shaft. A clutch drum of the other clutch device that accommodates a piston for the clutch device is arranged, and one of the forward and coasting clutch devices and the reverse clutch device are arranged radially overlapping each other. and the clutch disk of the other clutch device of the forward and coasting clutch devices and the one-way clutch are arranged radially overlapping at a position on the planetary gear unit side of the one clutch device with the one-way clutch inside. A clutch device for an automatic transmission for an automobile, characterized in that: