JPS6152449A - Hydraulic actuator of automatic speed change gear - Google Patents

Abstract

PURPOSE:To improve feeling characteristic by disposing a small air hole connected to the outside on an outer annular cylinder portion. CONSTITUTION:The above hydraulic actuator comprises a two-layer cylinder 2 having an inner annular cylinder portion 2A and an outer annular cylinder portion 2B disposed side by side on the outer periphery of the cylinder portion 2A, and a piston 3 having an inner annular piston portion 3A slidably fitted in the inner annular cylinder portion and an outer annular piston portion 2B slidably fitted in the outer annular cylinder portion 3B. In the hydraulic actuator of an automatic speed change gear constructed so that the working fluid is supplied and discharged to and from one of the annular cylinder portions through the other annular cylinder portion, a small air hole 20 connected to the outside is disposed on one annular cylinder portion. In this arrangement, it is possible to attain optimum transmission torque and a pressure up characteristic of a hydraulic servo.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluid pressure actuator for an automatic transmission that includes a two-layer cylinder section provided in two layers stacked in the radial direction.

[Prior Art] An automatic transmission installed in a vehicle or the like consists of a gear shifting FAI, a multi-disc clutch for engaging its components with other components or an automatic transmission case (transmission case), and a multi-disc clutch. A plurality of frictional engagement elements such as brakes, and said 1
1! A fluid pressure actuator such as a hydraulic servo is used to engage and release the engagement element, and the fluid pressure actuator is selectively operated according to the set position of the manual lever, vehicle speed, engine load, etc. to set a predetermined gear. It has a hydraulic control device configured. Said #Il? Of the I engagement requirements, fluid actuators for frictional engagement elements that require particularly high transmission torque capacity, such as multi-disc clutches for achieving forward travel, for example during first gear, have two annular elements in the radial direction. Cylinder parts are installed in parallel (Puta cylinder and these two
A combination U with one piston having two piston parts slidably mounted on each of the two cylinder parts is useful.

[Problem that the invention seeks to solve]

In this type of fluid pressure actuator, the working fluid is supplied to and discharged from one of the annular cylinder parts through the other annular cylinder part, so when the working fluid is supplied, the air inside the other annular cylinder part is flows into the one annular cylinder portion and is compressed by the inflowing hydraulic oil, which affects the operation of the piston.

Therefore, it is a frictional engagement element that is engaged to achieve forward running in an automatic transmission, and as shown in FIG. 2B, an inner annular piston portion 3△ slidably fitted into the inner annular cylinder portion, and an outer annular piston portion 3△ slidably fitted into the outer annular cylinder portion. The working fluid is supplied and discharged to and from the outer annular cylinder part 2B through the deep part of the inner annular cylinder part 2A and the outer annular cylinder part 2B. Automatic transmission and multi-disc clutch C1 connected via hydraulic oil supply oil passage 7a that communicates with the inner part.
In the hydraulic servo C-1, the pressure increase characteristics P2A and P2B, including the rise of the pressure inside each annular cylinder 2A and 2B, and the change in the output shaft torque T1 of the automatic transmission are determined by the third
The change occurred as shown by the solid line in the figure. The pressure in the outer annular cylinder 2A due to only the hydraulic oil shown in the graph of FIG. 3 is as shown by the broken line, and the distribution of diagonal lines is due to the effect of the trapped air. As a result, the peak m of transmission torque change
1.9 and m2 occur, indicating that the feeling at N-0278 is not good.

It is an object of the present invention to eliminate the adverse effects of the trapped air in the hydraulic actuator of an automatic transmission having the two-layer cylinder, and to reduce shift shock so that appropriate transmission torque changes and pressure increase characteristics of the hydraulic servo can be obtained. The present invention provides a fluid pressure actuator for an automatic transmission.

[Means for Solving the Problem] Several hydraulic actuators (hydraulic servo C-1 exemplified in FIG. 1) of the present invention are arranged in parallel on the inner annular cylinder portion 2A and its outer periphery. A two-layer cylinder 2 having an outer annular cylinder portion 2B, an inner annular piston portion 3A slidably fitted into the inner annular cylinder portion, and an inner annular piston portion 3A slidably fitted into the outer annular cylinder portion 3B. The piston 3 has an outer annular screw part 3B fitted into the piston 3, and the working fluid is supplied to and discharged from one of the annular cylinder parts through the other annular cylinder part. The fluid E of the automatic transmission [actuator] is configured such that one of the annular cylinder portions is provided with a small vent hole 20 communicating with the outside.

[Action and effect of invention] Since the present invention has the above configuration, it has the following effects.

Since the outer cylinder part is provided with a small ventilation hole 20 leading to the outside, the pressure increase characteristic of the outer annular cylinder 2B is P2B shown by the dashed line in Fig. 3, and the change in transmitted torque is also T2.
It becomes like this, and the feeling can be improved. It should be noted that, since the hydraulic oil is omnipresent around the outer periphery due to centrifugal force, it is desirable to provide this small vent hole 20 as close to the inner periphery of the outer cylinder as possible from the viewpoint of good air discharge.

[Example] Next, the present invention will be explained based on the embodiment shown in FIG.

14 is an intermediate transmission shaft of a transmission of a vehicle automatic transmission, C1 is a multi-plate frictional engagement element or latch, and C-
1 does not show the hydraulic servo that is its fluid pressure actuator.

A collar-shaped portion 14A with a large outer diameter is provided on the outer periphery of the rear portion (right side portion in the figure) of the transmission +ll1l114, and the collar-shaped portion 1
The rear end portion 15 at the rear of 4A has a cylindrical shape with a slightly larger outer diameter and extends to the right of the center hole 16. At the front end of the outer periphery 14G of the flange-shaped portion 14A, there is an outer cylindrical portion 1B extending from the outer periphery of the bottom wall portion of the bottom wall IA1A1 that is flush with the front surface 14D of the flange-shaped portion 14A, and from the outer cylindrical portion 1B. A cylinder drum 1 consisting of a clutch drum portion 1C which is further extended and has a spline 1D provided on its inner periphery is welded.

The hydraulic servo C-1 includes an inner annular cylinder portion (hereinafter referred to as the inner cylinder) 2A and an outer annular cylinder portion provided on its outer periphery (hereinafter referred to as the outer cylinder).
2B and the inner cylinder 2
A slidably inner annular piston part (hereinafter referred to as the inner piston) 3△, an outer annular piston part slidably fitted into the outer cylinder (hereinafter referred to as the outer piston) 3B, a piston 3 having an intermediate cylindrical portion 3C provided at the connecting portion between the inner piston and the outer piston, and return biasing means 4 for the piston 3.

The inner cylinder 2A of the two-layer cylinder is an intermediate cylinder of the piston that slides on the outer circumferential surface 14E of the rear end of the transmission shaft in this embodiment, and the outer circumference 14C of the tongue-shaped portion of the transmission shaft in this embodiment. Inner peripheral portion 3D of portion 3C and the brim portion 14A
It is formed by the rear surface 14F of. The outer cylinder 2B of the two-layer cylinder has an outer circumferential surface 14C of the brim portion 14A, an inner circumferential surface 1E of the outer cylindrical portion 1B of the drum 1, and an inner surface 1F of the bottom wall portion 1A of the drum 1. The bottom wall portion 1A is provided with a small ventilation hole 2o that mainly allows only air to pass through and provides a sufficiently large resistance to leakage of hydraulic oil.

The inner piston 3A of the piston has an inner periphery 3E that slides on the outer periphery 14E of the rear end of the transmission shaft, and the outer periphery is connected to the rear end of the inner periphery 3D of the intermediate cylindrical portion 3C of the piston, The outer piston 3B has an inner periphery 3D that slides on the outer periphery 14C of the flange portion of the transmission shaft, and an outer periphery 3G that comes into sliding contact with the inner periphery of the outer cylindrical portion of the drum.
A protrusion 3H is provided around the rear surface between the piston 3B and the outer piston 3B. Outer annular piston portion 3B of piston 3
A relief valve 3e consisting of a plug 3a with an orifice and a ball valve 3b is attached to.

The return biasing means 4 includes a snap ring 4B fitted into a groove 4A provided on the outer periphery of the rear end of the transmission shaft 14.
, an annular plate-shaped spring retainer IC1 whose inner peripheral part is locked by the snap ring 4B and which is fitted onto the rear end part 14B of the transmission shaft between the protrusion of the piston and the outer peripheral part of the spring retainer 4C. The return spring 4D is interposed between the return springs 4D and 4D.

The transmission shaft 14 is provided with a hole 14 forming a lubricating oil supply path and a side hole 6 for supplying hydraulic oil to the inner cylinder 2A. In this embodiment, the sleeve hole 6 includes an axial hole 6A in which the center hole 16 is formed so that the center hole 16 is open and a ball stopper 6a is fitted into the open end, a radial hole 6B that communicates the axial hole 6A with the outside of the axis, and the above-mentioned radial hole 6A. Axial hole 6A and the inner cylinder 2
It consists of a diagonal hole 6C that communicates with A. In addition, the transmission shaft 1
The collar-shaped portion 14A of No. 4 is provided with an inner/outer cylinder communication oil passage 7 that communicates the inner cylinder 2A and the outer cylinder 2B. In this embodiment, this inner and outer cylinder communication oil passage 1 is an axial hole 7 provided from the rear surface 14F of the brim portion.
A, a hydraulic oil supply oil passage 7 consisting of a radial hole 7B opened at an intermediate position of the outer circumferential surface 14C of the collar, and a shaft hole 8A and a shaft hole 8Δ formed in the axial direction from the rear surface 14F of the collar.
, a radial hole 8B opened at the front side of the outer peripheral surface of the collar portion, and a check ball 8 provided in the shaft hole 8A.
and a discharge oil passage 8 for hydraulic oil consisting of C.

The clutch C1 includes an outer friction plate 9A meshed with a spline 1D with the clutch drum 1C, a clutch hub 9BJ5 provided coaxially with the clutch drum and connected to an output member (not shown), and an outer periphery of the clutch hub. The inner friction plate 9D is meshed with a spline 9C provided on the outer friction plate 9D and overlaps the outer friction plate 9Δ.

In this hydraulic servo C-1, when hydraulic oil is supplied from the oil passage 6 in a state where the piston 3 is stopped at the innermost part of the cylinder 2, pressure oil first enters the inner cylinder 2A. A part of the air in the inner cylinder 2A enters the outer cylinder 2B. In addition, the hydraulic oil in the inner cylinder 2A that normally gathers around the outer circumference due to centrifugal force enters the outer cylinder 2B from the oil passage 7, and while pushing out air through the small vent hole 20, the pressure inside the outer cylinder 2B increases. will continue to increase.

Since the hydraulic oil in the cylinder 2B also gathers around the outer periphery due to the action of centrifugal force, it is desirable to form the small vent hole 20 as close to the inner periphery of the outer cylinder as possible from the viewpoint of smooth air discharge. desirable.

As a result, the piston 3 first compresses the return spring 4D and is quickly displaced by the play gap between the piston 3 and the friction plates 9A and 9D. Next, as the hydraulic pressure increases, the frictional force between the friction plates 9A and 9D is increased. As a result, the transmission torque capacity of the clutch C1 changes as shown by the dashed line in FIG. 3, reducing shift shock during gear changes.

FIG. 2 shows an automatic transmission for a vehicle using the hydraulic actuator for an automatic transmission according to the present invention.

Automatic transmission 100 includes a hydraulic torque converter 200, a transmission 300, and a hydraulic control device 400.

The transmission 300 includes an overdrive planetary gear transmission 10 comprising a first planetary gear set p1, one multi-disc clutch Go operated by a hydraulic servo, one multi-disc brake BO1 and one one-way latch FO; Planetary gear set p2, third planetary gear set p3, 2 operated by hydraulic servo
1 multi-plate clutch C1, C2, 1 belt brake B
1. It is composed of an underdrive planetary gear transmission 40 with three forward speeds and one reverse speed, which is equipped with two multi-disc brakes B2 and B3 and two one-way latches Fl and F2.

The automatic transmission case 110 includes a torque converter 200
A transmission case 130 integrally formed with a torque converter housing 1201 that accommodates the overdrive planetary gear transmission 10 and each chamber that accommodates the underdrive planetary gear transmission 40, the automatic transmission 1
Extension housing 140 that covers the rear side of 00
These torque converter housings 120
The transmission case 130 and the extension housing 140 are each coaxially fastened with a large number of bolts.

The torque converter 200 is housed in a torque converter chamber 121 of a torque converter housing 120 with a front side (engine side) and an engine output shaft (not shown).
a front cover 111 connected to the front cover 1;
an annular plate-shaped rear cover 112 welded to 11 at the outer periphery;
A pump impeller 205 provided around the inner peripheral wall of the rear cover 112, a turbine runner 208 disposed opposite to the pump impeller 205, and the turbine runner 2.
06, a stator 201 supported by a fixed shaft 203 via a one-way clutch 202, a friction surface 20 provided on the inner surface of the front cover 111, and a turbine hub 208 which is an output member.
It consists of an annular plate-shaped clutch disc 50 whose inner periphery is connected to the front cover 111 and the turbine hub 20.
8 is provided with a direct coupling clutch (lock-up clutch) 80 that is directly connected to the clutch 8. The torque converter chamber 1
21 and transmission case 1 that continues behind it
An oil pump front cover 151 which houses an oil pump 150 therein and has a cylindrical portion 152 protruding forward in the center is located between the cylindrical transmission seedling 132 and the cylindrical transmission seedling 132.
is bolt-fitted and fastened to the front end surface of the transmission case 130, and on the rear side of the oil pump front cover 151 is a cylindrical front having a coaxial center with the cylindrical portion 152 and protruding rearward. 1~Sabo 1" 1
An oil pump cover 154 having 53 is fastened. The oil pump front cover 151 and the oil pump cover 154 form an oil pump housing 155, and the torque converter seedling 121 and the transmission chamber 132 form an oil pump housing 155.
It is a dividing wall between the two. In addition, there is an overdrive tjm in the middle of the transmission chamber 132. An intermediate support wall 159 that partitions the i4 chamber 133 and the underdrive mechanism chamber 134 and has a cylindrical center support 158 that projects rearward is fitted as a separate mTi. At the rear part, a rear support wall 157 having a cylindrical rear support 156 projecting forward is provided in an integral VI structure. A transmission chamber 132 is formed between the oil pump housing 155 and the rear support wall 157, and an output shaft chamber 141 of the transmission is formed between the rear support wall 157 and the extension housing 1400. An electronically controlled sensor rotor 143 and a speedometer drive gear 144 are provided, and a sleeve yoke (not shown) is inserted through the rear end.

Torque converter 2 is installed inside the front support 153.
The one-way clutch 2 supporting the stator 201 of 00
A fixed shaft 203 of No. 02 is fitted, and the input shaft 11 of the transmission, which is the output shaft of the torque converter 200, is rotatably supported inside the fixed shaft 203. The input shaft 11 has a large-diameter rear end portion 12 with a flange portion 12a provided around the rear of the front support 153, and the rear end portion 1
A center hole 13 is formed in the center of 2. The input shaft 1
1, an intermediate power transmission shaft 14 is rotatably mounted at the rear of the intermediate power transmission shaft 14, the tip of which slides into the center hole 13 and is arranged in series with the input shaft 11. A rearward-facing central hole 16 is formed in which the tip of the output shaft 36 slides. The output shaft 36 is spline-fitted at an intermediate portion 37 with a flange plate 82 provided with a rearwardly protruding shaft support 81 that meshes with the ring gear R2 of the third planetary gear set p3, and at a rear portion 38 is spline-fitted with the sleeve yoke. They are mated.

In the overdrive mechanism chamber 133, the input shaft 1
A first planetary gear set p1 is provided on the rear side of the
The ring gear RO has a flange plate 22 on the intermediate transmission shaft 14.
The planetary carrier PO is connected to the input shaft 1 through
The sun gear SO is connected to the flange portion 12a of the inner race shaft 23 and is formed on the inner race shaft 23. On the front side of the first planetary gear set p1, a first hydraulic servo drum 24 that opens rearward is fixed to an inner race shaft 23, and an annular piston 25 is housed between its outer peripheral wall and the inner race shaft 23. A return spring 26 is provided on the inner race shaft 23 side while forming the hydraulic servo C-Q of the clutch CO.
, a clutch CO is attached to the inside of the outer circumferential wall, and is connected to the carrier 1f0 via the clutch CO. A one-way latch FO for connecting the inner race shaft 23 to the inner race is provided on the inner periphery of the first hydraulic servo drum 24, and an outer race 27 and a transmission case 13 are provided on the outer periphery of the one-way latch FO.
A clutch CO and a brake BO are provided between 0 and 0,
A piston 29 is fitted into the front side of the intermediate support wall 159 on the rear side to form a hydraulic servo B-0 of the brake BO, and a return spring 32 provided on the inner periphery 31 of the outer cylinder portion of the intermediate support wall 159 is fitted.

Inside the underdrive mechanism chamber 134, at the front, a second hydraulic servo drum 41 that opens rearward is rotatably fitted onto the center support 158, and an annular piston 42 is fitted between its inner and outer circumferential walls to control the hydraulic pressure of the clutch C2. In addition to forming a servo C-2, a return spring 44 is attached to the inner circumferential wall, and a clutch C2 is attached to the inner side of the outer circumferential wall. On the rear side of the second hydraulic servo drum 41 is a third hydraulic cylinder for forming the cylinder 2 of the hydraulic actuator of the automatic transmission of the present invention, which opens rearward and has the cylindrical clutch hub 35 welded to the front. The servo drum 1 is fixed to the flange portion 14A of the rear end portion 15 of the intermediate transmission shaft 14, and the annular piston 3 is fitted between the rear end portion 15 and the outer peripheral wall to form the hydraulic servo C-1 of the clutch C1. At the same time, a return biasing means 4 is provided on the inner circumferential side, and a clutch C2 is attached to the outer circumference of the cylindrical clutch hub 35, and the second and third hydraulic servo drums 41 are
．． 46 are connected. The third hydraulic servo drum 46
On the rear side, second planetary gear sets 1 to p2 are provided, the ring gear R1 of which is connected to the third hydraulic servo drum 46 via the cylindrical clutch hub 48 and the clutch C1, and the rear gear P1 of the key 11 is The sun gear S1 is spline-fitted to the tip of the output shaft 36, and is integrally formed with the sun gear shaft 45. In addition, the second and third hydraulic servo drums 41
．． 46 and the second planetary gear set p2 in a minimum space, the connecting drum 60 has its leading end flush with the outer periphery of the second hydraulic servo drum 41, and its rear end covers the second planetary gear set p2. 1) It is connected to the sun gear shaft 45 on the rear side of 2, and a belt brake B1 is provided on the outer circumferential side.

Transmission case 1 on the rear side of the brake B2
The brake disc b2 of the brake B2 and the brake disc b3 of the brake B3 are spline-fitted from the front to the spline 75 formed on the inside of the transmission case 30. A piston 77 is fitted into the annular hole between the two to form a hydraulic servo B-3 of the brake B3, and a return spring 79 of the hydraulic servo B-3 is supported by a flange plate 82 attached to the tip of the rear support 156. There is. Inside the brake B2, there is a one-way latch F1 with the sun gear shaft 45 as an inner race.
is provided, the outer race 39 is connected to the brake B2, and the return force means and the inner race 83 are spline-fitted on the rear side of the one-way clutch F1 with the fourth hydraulic servo drum 72 at the outer inner diameter. F
2 is installed. In the third planetary gear set p3, the sun gear S2 is formed integrally with the sun gear shaft 45, the carrier P2 is connected to the outer race 86 of the one-sided clutch F2 on the front side, and is also connected to the brake B3. A ring gear R2 having a circumference of 85 is connected to the intermediate portion 37 of the output shaft 36. When the shift lever of the automatic transmission is selected to the parking (P) position, the parking claw 84 engages with the parking gear 85 to fix the output shaft 36.

An intermediate cylinder 71 is press-molded on the annular fourth hydraulic servo drum 72 opening forward, and an annular piston 73 is fitted between the fourth hydraulic servo drum 72 and the intermediate cylinder 71, and the hydraulic servo 8- of the brake B2 is inserted into the intermediate cylinder 71. 2, a return spring 74 is installed between the inner peripheral wall of the fourth hydraulic servo drum 72 and the intermediate cylinder 71, and a brake B2 is installed inside the outer peripheral wall.

The transmission 300 changes the transmission case 1 according to vehicle driving conditions such as vehicle speed and throttle opening.
The engagement of each clutch and brake is controlled by hydraulic pressure selectively output to the hydraulic servo of each Jl engagement device from a hydraulic control mounting 400 in a valve body 403 built in an oil pan 401 fastened to the lower part of the valve 30 by a bolt 402. The gears are engaged or released, resulting in four forward speeds or one reverse speed change. The operation of each clutch, brake, and one-way clutch and the gear position (RANGE) achieved
- Examples are shown in Table 1.

Table 1 In Table 1, E indicates that the corresponding clutch, brake, or one-way clutch is engaged.

(L) indicates that the corresponding one-sided clutch is engaged only in the engine drive state and is not engaged in the engine brake state. Zaraani L is engaged in the corresponding one-sided clutch engine drive state, but
This indicates that the engagement is not necessarily required (lock) since power transmission is guaranteed by a clutch or brake installed in parallel. Zarani f
indicates that the corresponding one-sided clutch is free.

A rough cross indicates that the corresponding clutch and brake are released.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of a fluid pressure actuator for an automatic transmission of the present invention, FIG. 2 is a sectional view of an automatic transmission employing the fluid pressure actuator, and FIG. 3 is a sectional view of the internal pressure of the inner and outer annular cylinder parts. 3 is a graph showing changes in the transmission torque capacity of the frictional engagement element according to the rise characteristic of the frictional engagement element.

Claims (1)

[Scope of Claims] 1) A two-layer cylinder having an inner annular cylinder part and an outer annular cylinder part arranged in parallel on the outer periphery thereof, and a two-layer cylinder that is slidably fitted into the inner annular cylinder part. a piston having an inner annular piston part and an outer annular piston part slidably fitted in the outer annular cylinder part, the actuation of one of the annular cylinder parts; A fluid pressure actuator for an automatic transmission in which fluid is supplied and discharged through the other annular cylinder part, wherein the one annular cylinder part is provided with a small ventilation hole communicating with the outside. pressure actuator. 2) The automatic transmission according to claim 1, wherein the one annular cylinder is an outer annular cylinder, and the small ventilation hole is provided at the innermost peripheral part of the cylinder bottom wall. hydraulic actuator.