JPH0676830B2 - Automatic transmission transmission clutch device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission, and more particularly to improvement of an automatic transmission including a mechanism for performing creep control of a vehicle.

(Prior Art) A conventional automatic transmission is usually equipped with a torque converter on the engine side, and engine power is transmitted to the transmission through this torque converter, and a desired speed change is performed by a speed change mechanism. Steps are given. In such an automatic transmission with a torque converter, engine power is slightly transmitted to the power transmission path via the torque converter when the shift position is outside the stop range even when the accelerator pedal is open. This causes a so-called creep phenomenon in which the vehicle slightly moves. This creep phenomenon can be effectively utilized when performing idle running or when starting on a slope, and this is one of the advantages of the automatic transmission with a torque converter. . On the other hand, however, the creep phenomenon is accompanied by energy loss due to fluid friction in the torque converter, and therefore adversely affects fuel economy. JP-A-58-202116 discloses an automatic transmission with a torque converter, which is provided with a creep prevention mechanism for preventing the occurrence of a creep phenomenon in order to efficiently transmit power, and prevents creep during warm-up operation. A technique is disclosed in which control is released to improve warm-up efficiency and to warm a shack by sudden start. The low speed clutch of the disclosed device is controlled to be turned on and off by the operation of a fluid actuator in which a single hydraulic chamber is formed. During warm-up operation, hydraulic pressure is introduced into the hydraulic chamber, A clutch is connected to prevent the sudden start by using the function of the torque converter to cause a creep phenomenon, and to improve the warm-up efficiency by utilizing the heat generation effect of the fluid friction in the torque converter. When the warmed-up state is removed, the clutch is disengaged to prevent creep and improve fuel economy.

(Problems to be Solved) In the automatic transmission disclosed in JP-A-58-202116, the buffer function of the torque converter is an indispensable factor in preventing sudden start. However, the torque converter is always accompanied by friction loss in its operating state. Therefore, the creep control of the disclosed device is limited in terms of improving fuel efficiency in that the torque converter is premised. Is to have.

(Means for Solving the Above Problems) The present invention is configured to solve the above problems. In an automatic transmission of a type that does not use a torque converter, the creep control is simple and reliable. It is an object of the present invention to provide a starting clutch for an automatic transmission that enables the vehicle to perform a smooth starting operation. The starting clutch of the present invention is a shift gear mechanism having a plurality of shift stages that can be automatically switched,
A clutch element for transmitting a starting torque for starting the vehicle and a creep control torque for causing the creep of the vehicle to the gear transmission mechanism according to the connection state, and a connection state of the clutch element. And a fluid actuator for controlling, wherein the actuator comprises:
A pressure receiving surface on which a starting control fluid pressure for giving the starting torque and a creep control fluid pressure for giving the creep control torque selectively act, is formed,
The pressing force of the starting fluid pressure on the pressure receiving surface is larger than the pressing force of the creep control fluid pressure. In order to obtain different clutch contact pressures during starting and during creep control, the first pressure chamber in which the starting fluid pressure acts and the second pressure chamber in which the creep control fluid pressure acts are separately provided. It may be formed on the actuator so that the pressure receiving area of the first pressure chamber is larger than the pressure receiving area of the second pressure chamber, whereby the clutch transmission torque at the time of starting is transmitted to the clutch at the time of creep control. It can be greater than torque. Further, the first pressure chamber and the second pressure chamber are communicated with each other via a check valve so that the fluid pressure acts on both the first pressure chamber and the second pressure chamber at the time of starting to prevent creep. At the time of control, the fluid pressure may be applied only to the second pressure chamber. Further, different fluid pressures may be applied to the actuator during start-up and during creep control to obtain the start-time clutch connection state and the creep-control time connection state, respectively. In this case, it is not always necessary to provide two pressure chambers and provide different pressure receiving areas. In order to prevent sudden start, an orifice or the like may be provided in the start fluid passage so that the fluid pressure acting on the actuator is gradually increased.

(Description of Embodiments) Hereinafter, embodiments in which the present invention is applied to a parallel shaft gear type automatic transmission will be described with reference to the drawings.

As shown in FIG. 1, an automatic transmission 1 includes an input shaft 10 in a transmission case 2, the front end of which is connected to an engine output shaft 3 via a flywheel 4 and a buffer disc 5, and an input shaft 10 of the input shaft 10. An output shaft 20 arranged coaxially at the rear and having a mounting drum 6 of a propeller shaft (not shown) coupled to the rear end thereof.
And a counter shaft 30 arranged in parallel with the shafts 10 and 20, a plurality of gear trains for transmitting and disconnecting power between the shafts 10, 20, 30 and a friction stic and a one-way clutch. It has been configured.

A first gear 41 is loosely fitted to the intermediate portion of the input shaft 10, and a second gear 42 that is always meshed with the gear 41 is spline fitted to the front portion of the counter shaft 30. The first gear train I is constituted by 41 and 42. Then, a wet multi-plate type first connecting and disconnecting the input shaft 10 and the first gear 41 is provided on the input shaft 10.
A friction clutch 51 is provided. The first friction clutch 51 includes a drum 51a splined to the input shaft 10 and a hub 51b integrally formed with the first gear 41.
And a plurality of friction plates 51c disposed between the two and alternately spline fitted to the drum 51a and the hub 51b, and the friction plates 51c are fastened to each other when the working pressure is introduced, and the drum 51a.
And a hub 51b, in other words, a piston 51d that connects the input shaft 10 and the first gear 41.

Further, the third gear 43 is fitted to the rear end of the input shaft 10 via the one-way clutch 61, and
The fourth gear 44 that constantly meshes with the gear 43 is the counter shaft 30.
Loosely fitted to the second gear train by these gears 43, 44.
II is configured. Then, the counter shaft 30
A second friction clutch 52 for connecting and disconnecting the shaft 30 and the fourth gear 44 is provided above the clutch 52.
Even the drum splined to the counter shaft 30
52a, a hub 52b connected to the sleeve-like extension 44a of the fourth gear 44, a plurality of friction plates 52c arranged between the drum 52a and the hub 52b, and a plurality of these friction plates 52c when operating pressure is introduced. A piston 52d that fastens a friction plate 52c to couple the drum 52a and the hub 52b, that is, the counter shaft 30 and the fourth gear 44.
It consists of and.

Further, a third friction clutch 53 is arranged between the one-way clutch 61 at the rear end of the input shaft 10 and the front end of the output shaft 20. This clutch 53 is also a drum 53a spline-coupled to the output shaft 20, a hub 53b integral with the outer race 61a (third gear 43) of the one-way clutch 61, and a plurality of friction plates arranged between them. 53c, and a piston 53d that fastens these friction plates 53c when the operating pressure is introduced and connects the bub 53b and the drum 53a. Then, when the third friction clutch 53 is engaged and the one-way clutch 61 is locked, the input shaft 10
And the output shaft 20 are coupled to each other. Here, on the input shaft 10, an engine brake friction clutch 56 is provided in parallel with the one-way clutch 61. The clutch 56 is integrally formed with the drum 56a splined to the input shaft 10 and the outer race 61a of the one-way clutch 61 and the hub 56b.
And a plurality of friction plates 56c arranged between them, and a piston 56d for connecting the drum 56a and the hub 56b by fastening these friction plates 56c. Therefore, when the friction clutch 56 is engaged, the one-way clutch 61
Even when is in a free state, the input shaft 10 and the hub 53b of the third gear 43 or the third friction clutch 53 are connected.

On the other hand, a fifth gear 45 is integrally formed on the rear portion of the counter shaft 30, and a sixth gear 45 that constantly meshes with the gear 45 is formed.
The gear 46 is loosely fitted to the output shaft 20, and the gears 45 and 46 form a third gear train III.
A fourth friction clutch 54 for connecting and disconnecting the output shaft 20 and the sixth gear 46 is arranged on the output shaft 20. This fourth friction clutch 54 has the above-mentioned third friction clutch.
A drum 54a integrally formed with the drum 53a of the friction clutch 53 and spline-coupled to the output shaft 20;
Hub 54b integrated with the sixth gear 46, drum 54a and hub
A plurality of friction plates 54c arranged between the 54b and a piston 54d for connecting the friction plates 54c when the working pressure is introduced to the hub 54b of the drum 54a, that is, the output shaft 20 and the sixth gear 46. It is composed of.

Further, a seventh gear 47 is spline-fitted to the rear end portion of the count shaft 30, and an eighth gear 48 which is constantly meshed with the gear 47 is loosely fitted to the output shaft 20. The fourth gear train IV is constituted by 48. Then, a fifth friction clutch that connects and disconnects the output shaft 20 and the eighth gear 48 to the rear portion of the output shaft 20.
55 are arranged. This clutch 55 is also a drum 55a splined to the output shaft 20, a hub 55b integral with the eighth gear 48, the drum 55a and the hub 55b.
A plurality of friction plates 55c disposed between the drum 55c and the hub 55c by fastening the friction plates 55c when the operating pressure is introduced.
b, that is, a piston 55d that connects the output shaft 20 and the eighth gear 48. This friction clutch 5
The piston 55d and the drum 55a of 5 constitute an actuator for operating the clutch 55. As shown in detail in FIG. 2, in this example, two hydraulic chambers, a first hydraulic chamber 90 and a second hydraulic chamber 91, are formed between the rear surface of the piston 55d and the front surface of the drum 55a. The hydraulic passage 92 is provided in the first hydraulic chamber 90.
However, hydraulic passages 93 are connected to the second hydraulic chambers 91, respectively. The first and second hydraulic chambers 90, 91 are connected to each other by a communication passage 94. A check valve 95 provided with a drift-on ball is arranged in the communication passage 94, and the valve 95 allows only the hydraulic flow from the first hydraulic chamber 90 to the second hydraulic chamber.

Therefore, when the hydraulic pressure is introduced into the first hydraulic chamber 90 through the hydraulic passage 92, the hydraulic pressure is also introduced into the second hydraulic chamber through the communication passage 94, and presses the piston 55d in both hydraulic chambers. . Therefore, in this case, the pressure receiving area of the piston 55d is large and the contact pressure of the friction plate is also large. As a result, the clutch 55 gives a large transmission torque, that is, a first speed (for starting) torque. Further, when the hydraulic pressure is introduced into the second hydraulic chamber 91 through the hydraulic passage 93, the communication passage 94 is blocked, so that the hydraulic pressure acts only on the first hydraulic chamber 91. Therefore, the contact pressure of the friction plate 55c becomes comparatively weak, and the transmission torque, that is, the creep control torque that causes the creep phenomenon is given. That is, the friction clutch 55 is
It functions in two different connection states, and transmits the starting torque or the creep control torque in each of the connection states. Third
As shown in the figure, the first hydraulic chamber 90 is connected to the starting hydraulic pressure generating device 96 via the hydraulic passage 92, and the second hydraulic chamber 91 is connected to the hydraulic passage 93.
Are connected to the creep control hydraulic pressure generation circuit 97 via the. In this case, two switching valves 98, 99 of spring return type are arranged in the hydraulic passage 93. The starting hydraulic pressure generator 96 generates hydraulic pressure for giving the friction clutch 55 a first speed, that is, a connection state of the friction clutch 55 having a transmission torque for starting, and the hydraulic pressure is generated via the hydraulic passage 92. The hydraulic pressure is supplied to the actuator, and the creep control hydraulic pressure generating device 97 generates a hydraulic pressure for providing a friction clutch connection state in which the vehicle has a transmission torque that causes a creep phenomenon and generates a hydraulic pressure passage 93. The hydraulic pressure is supplied to the actuator via. In this example, the starting hydraulic pressure generator 96 and the creep control hydraulic pressure generator 97 are connected to a common hydraulic power source 100, and adjust the hydraulic pressure generated by the hydraulic pressure source for the above-mentioned starting and creep control. It is composed of a pressure valve and a control circuit for controlling the pressure regulating valve. The control circuit of the starting hydraulic pressure generation device 96 of the present example is input with a signal from the accelerator opening sensor 101 representing the amount of depression of the accelerator and a signal from the rotation sensor 102 representing the engine speed, and these signal values are given. It is designed to generate a corresponding hydraulic pressure. The switching valves 98 and 99 are both on / off valves, and the control port 98a of the switching valve 98 is connected to a hydraulic passage branched from the hydraulic passage 92, and the hydraulic pressure from the starting hydraulic pressure generator 96 is
When introduced into the port 98a, the spool 98b moves to the right in FIG. 3 to block the communication between the inlet port 98c and the outlet port 98d of the switching valve 98. As a result, the hydraulic pressure supply from the creep control hydraulic pressure generation device 97 to the second hydraulic pressure chamber 91 is cut off, and the reverse flow of the hydraulic pressure from the starting hydraulic pressure generation device 96 introduced into the second hydraulic pressure chamber through the communication passage 94 occurs. It is supposed to be prevented. Furthermore, the control port of the switching valve 99
99a is connected to the hydraulic power source 100 and is also connected to the drain passage 103. A solenoid valve 104 for opening and closing the passage 103 is arranged in the drain passage 103, and the solenoid valve 104 is controlled by a manual switch 105.

Further, the one-way clutch 61 locks when the rotation speed of the input shaft (inner race) 10 is about to become higher than the rotation speed of the outer race 61a with respect to the predetermined rotation direction, and the rotation of the input shaft 10 is prevented from rotating.
When it is transmitted to 61a and the rotation speed of the outer race 61a exceeds the rotation speed of the input shaft 10, it idles. Also,
The first gear train I has a gear ratio of about 1, and the second gear train II
Is decelerated when the rotation is transmitted from the third gear 43 to the fourth gear 44, the third gear train III is decelerated when the rotation is transmitted from the fifth gear 45 to the sixth gear 46, and the fourth gear train IV is the seventh gear. The diameters of the gears 41 to 48 are set so that the rotation speed is transmitted from the gear 47 to the eighth gear 48 at a reduction ratio larger than that of the third gear train III.

Further, the fifth friction clutch 55 arranged at the rear portion of the output shaft 20 has a larger diameter than the other friction clutches 51 to 54 and 56, and is located rearward of the rear end portion of the counter shaft 30. It is arranged so as not to interfere with the counter shaft 30.

In addition to the above configuration, a reverse speed gear train V is provided between the counter shaft 30 and the output shaft 20. The gear train V is loosely fitted on a drive gear 71 integrally formed on the counter shaft 30, an idle gear 73 on an idle shaft 72 which is always meshed with the gear 71, and an output shaft 20 which is always meshed with the gear 73. Combined driven gear
It consists of 74 and. And output shaft
A spline 75 is formed on the 20 and the spline 74 of the same shape is formed on the side surface of the driven gear 74 adjacent to this.
When the sleeve 76 slidably fitted to the former spline 75 is fitted over both splines 75 and 74a by the shift fork 77, the driven gear 74 is coupled to the output shaft 20. It is like this.

Further, in this embodiment, the parking gear 81 is fixedly installed on the outer periphery of the drum 55a of the fifth friction clutch 55,
When the parking pole 82 is engaged with 1, the above drum 55a
The output shaft 20 is fixed via the.

Further, the fourth gear 44 on the counter shaft 30 has a shaft
A power take-off gear 84 supported by 83 is meshed,
The power used for various works other than vehicle driving is taken out from the.

Next, the power transmission state in each gear of the automatic transmission will be described with reference to the clutch operation table in Table 1 and the skeleton diagrams in FIGS. Here, in Table 1, the mark ◯ indicates the engaged state for the friction clutch and the locked state for the one-way clutch. Further, the mark (○) indicates the state of being engaged, but not involved in power transmission.

First, at the time of starting the vehicle, the second friction clutch 52, the fifth friction clutch 55, and the one-way clutch 61 are brought into the operating state, so that the starting torque from the engine is transmitted to the drive system. In this case, the starting hydraulic pressure generating device 96 generates a starting hydraulic pressure in the hydraulic passage 92 according to the accelerator opening and the engine speed. This starting hydraulic pressure is
First, it is introduced into the first hydraulic chamber 90 and then into the second hydraulic chamber 91 through the communication passage 94, and the piston 55d is pressed in both hydraulic chambers 90 and 91. As a result, the friction plate 55c is
With a relatively high contact pressure, the friction clutch 55 transmits sufficient torque to launch. In this case, the output of the engine is transmitted from the input shaft 10 via the one-way clutch 61 to the third gear 43 of the second gear train II, and further to the fourth gear.
It is input from the gear 44 to the counter shaft 30 via the second friction clutch 52. Then, the output shaft 20 is further passed from the counter shaft 30 through the seventh and eighth gears 47 and 48 constituting the fourth gear train IV and the fifth friction clutch 55.
Be transmitted to. In this case, the rotation of the isoput shaft 10 is decelerated by the second gear train II, and is also greatly decelerated by the fourth gear train IV and transmitted to the output shaft 20, so that the first speed state with a large reduction ratio is obtained. As a result, the starting operation is performed.

In this example, the magnitude of the hydraulic pressure generated in the starting hydraulic pressure generator 96 is controlled so as to differ depending on the opening degree of the accelerator and the rotational speed of the engine. When the accelerator opening is small, the starting hydraulic pressure is generated in proportion to the accelerator opening, and when the accelerator opening is large, the starting hydraulic pressure is generated in proportion to the rate of change of the engine speed. . Therefore, at the time of starting, the contact pressure of the friction plate 55c increases as the depression amount of the accelerator petal increases, and thus the transmission torque of the clutch 55 increases. Therefore, sudden start can be prevented. Also, when downshifting from the high speed stage to the first speed, the first speed state is obtained by the same operation.

Next, when shifting from the first speed to the second speed, as shown in Table 1, the first friction clutch 51 is newly engaged in the above-described first speed state. At this time, the rotation of the input shaft 10 is input to the counter shaft 30 from the first friction clutch 51 via the first and second gears 41 and 42 forming the first gear train I, and the counter shaft 30 is also rotated. Similarly to the case of the first speed, the rotation is transmitted to the output shaft 20 via the seventh and eighth gears 47 and 48 of the fourth gear train IV and the fifth friction clutch 55. In this case, the reduction ratio of the first gear train I is approximately 1, which is smaller than the reduction ratio of the second gear train II that transmits the rotation from the input shaft 10 to the counter shaft 30 at the first speed. A second speed state in which the reduction ratio is smaller than that in the first speed is obtained.

The shift from the first speed to the second speed is performed only by the engaging operation of the first friction clutch 51 as described above, and the second friction clutch 52, which was engaged at the first speed, is engaged even after the 1 → 2 shift. It is in a broken state. Therefore, the rotation transmitted to the counter shaft 30 is transmitted from the second friction clutch 52 to the fourth gear 44 to the third gear 43. In this case, the third gear 43
One-way clutch 61 between and input shaft 10
Since the outer race 61a side rotates at a high speed, the idling state occurs. Therefore, the rotation is not transmitted from the input shaft 10 to the counter shaft 30 via the second gear train II.

Further, when shifting from the second speed to the third speed, as shown in Table 1, the fourth friction clutch 54 is newly engaged and the fifth friction clutch 55 is released from the second speed state. for that reason,
The rotation of the input shaft 10 is transmitted from the first friction clutch 51 to the counter shaft 30 via the first and second gears 41 and 42 of the first gear train I, and the counter shaft 30
Is transmitted to the output shaft 20 via the fifth and sixth gears 45 and 46 of the third gear train III. In this case, the third
Countershaft 30 when the gear train III has a reduction ratio of 1 or 2
Since it is smaller than the reduction ratio of the fourth gear train IV that transmits the rotation from the output shaft 20 to the output shaft 20, the third speed state with a smaller reduction ratio can be obtained. In this case also, the second friction clutch 52
, The rotation of the counter shaft 30 is transmitted to the outer race 61a of the one-way clutch 61. However, since the one-way clutch 61 idles, the rotation of the input shaft 10 and the counter shaft via the second gear train II. It does not interfere with the rotation of 30. Then, the second friction clutch 52 is released at an appropriate time after the shift to the third speed.

In addition, as shown in Table 1, shifting from 3rd speed to 4th speed
The third friction clutch 53 is engaged, the fourth friction clutch 54 is released, and the one-way clutch 61 is locked from the state of the third speed (the state in which the second friction clutch 52 is already released). Therefore, the rotation of the input shaft 10 is transmitted from the one-way clutch 61 to the output shaft 20 via the third friction clutch 53. In this case, since the gear train does not pass through, the input shaft 10 rotates directly to the output shaft.
It is transmitted to 20 and the so-called directly connected fourth speed is obtained. In this case, the first friction clutch 51 that was engaged in the third speed
Is in the state of being fastened as it is. Therefore, the rotation of the input shaft 10 is changed to the fifth via the first friction clutch 51, the first gear train I, the counter shaft 30, and the fourth gear train IV.
It is transmitted to the hub 55b of the friction clutch 55,
Since 5 is open, no rotation is transmitted from the counter shaft 30 to the output shaft 20.

Further, when shifting from the fourth speed to the fifth speed, as shown in Table 1, the second friction clutch 52 is further engaged from the fourth speed state. Therefore, the rotation of the input shaft 10 is changed from the first friction clutch 51 to the first and second gears 41, 42 of the first gear train I.
Input to the counter shaft 30 via the second friction clutch 52 to the fourth and third gears of the second gear train II.
It is transmitted to the output shaft 20 via 44, 43 and the third friction clutch 53. That is, in this case, the rotation transmission from the counter shaft 30 to the output shaft 20 is performed through the second gear train II instead of the fourth gear train IV at the first and second speeds or the third gear train III at the third speed. In this case, the rotation speed is increased by transmitting the rotation of the second gear train II from the fourth gear 44 having a large diameter to the third gear 43 having a small diameter. As a result, the so-called overdrive fifth speed is obtained. In this case, the one-way clutch 61 runs idle for the same reason as in the 2nd speed.

Note that the one-way clutch 61 locks and transmits power at the 1st speed and the 4th speed, but at the time of coasting of a vehicle in which driving force is input from the output shaft 20, the one-way clutch 61 idles to automatically shift gears. Aircraft 1 is in neutral. Therefore, when the engine brake is applied during coasting, as shown in Table 1, the engine brake friction clutch 56 arranged in parallel with the one-way clutch 61 is engaged, and the one-way clutch 61 is replaced by a power clutch. To convey. Therefore, in this case as well, the predetermined shift speed is obtained and the engine brake is operated.

At the reverse speed, the one-way clutch 61 is locked and the second friction clutch 51 is engaged, and the driven gear 74 of the reverse speed gear train V is coupled to the output shaft 20 via the sleeve 76. Therefore, the rotation of the input shaft 10 depends on the one-way clutch 61 and the second gear train I.
I, the second friction clutch 52, the counter shaft 30, and the reverse speed gear train V are transmitted to the output shaft 20, but the reverse speed gear train V has an idle gear.
Since 73 is provided, the rotation direction of the output shaft 20 is reversed.

Further, when the creep control is performed, both the two switching valves 98 and 99 are in the state shown in FIG. 3, that is, the starting hydraulic pressure acts on the control port 98a of the switching valve 98. The hydraulic pressure from the creep control hydraulic pressure generation device 97 is supplied to the second hydraulic pressure passage 93 through the hydraulic pressure passage 93, provided that the manual switch 105 is turned on and the solenoid valve 104 opens the drain passage 103. It is introduced into the hydraulic chamber 91. In this case, since the communication passage 94 is cut off, the hydraulic pressure acts only on the second hydraulic chamber 91, the contact pressure of the friction plate 55c becomes relatively small, and the friction clutch 55 becomes less than the starting torque described above. Also transmits a small creep control torque. Therefore, in this case, the engine output is transmitted from the input shaft 10 to the third gear 43 of the second gear train II via the one-way clutch 61, and further from the fourth gear 44 to the second friction clutch 52 to the counter shaft. The seventh and eighth gears 47 and 48 which are inputted to the counter shaft 30 and further constitute the fourth gear train IV from the counter shaft 30 and the fifth friction clutch 55.
Is slightly transmitted to the output shaft 20 via. As a result, a creep phenomenon of the vehicle occurs, and the vehicle can be effectively used when the vehicle is running on an idle or when starting on a slope. If the accelerator pedal is depressed, the hydraulic passage
The hydraulic pressure from the starting hydraulic pressure generator 96 is supplied via 92 to the switching valve 98.
3 to move the spool 98b to the right against the spring force in FIG. 3 to block the communication between the inlet port 98c and the outlet port 98d. To the second hydraulic chamber 91 is automatically cut off and the creep control is stopped. When the manual switch 105 is turned off, the solenoid valve 104 closes the drain passage 103, so that the hydraulic pressure from the hydraulic pressure source 100 is applied to the switching valve 99.
Since the switching valve 99 closes the hydraulic passage 93 by acting on the control port 99a, the creep control is not similarly performed. The switching valve 98 can also be configured as a one-way valve.

(Effects of the Present Invention) According to the present invention, it is possible to perform the same creep control as that in an automatic transmission with a torque converter in an automatic transmission of a type that does not use a torque converter, which is advantageous in terms of fuel consumption. An automatic transmission can be provided. Further, in the present invention, since the starting clutch is used to provide the creep control, the structure is relatively simple and compact, and it is advantageous in terms of cost and layout.

[Brief description of drawings]

1 shows an embodiment of the present invention. FIG. 1 is a sectional view showing the entire structure of an automatic transmission, FIG. 2 is a detailed sectional view of a low speed friction clutch, and FIG. 3 is FIG. 3 is a control system diagram of the friction clutch of FIG. 1 …… Automatic transmission, 10 …… Input shaft, 21 ……
Output shaft, 30 …… Counter shaft, 41〜
48 …… Gear, 51 to 55 …… Friction clutch (55 …… Low speed gear friction clutch), 61 …… One way clutch, 90 ……
1st hydraulic chamber, 91 ... 2nd hydraulic chamber, 92, 93 ... hydraulic passage,
94 …… Communication passage, 95 …… Check valve, 96 …… Starting hydraulic pressure generator, 97 …… Creep control hydraulic pressure generator, 98,99 …… Switching valve, 104 ……
Solenoid valve, 105 ... Manual switch.

Claims (1)

[Claims] 1. A speed change gear mechanism having a plurality of shift stages that can be automatically switched, and a start torque and a vehicle creep which are incorporated in the gear speed change mechanism to start the vehicle according to a connection state. And a fluid actuator for controlling a connection state of the clutch element, wherein the actuator includes a start control fluid pressure for applying the start torque and the fluid control actuator. A pressure receiving surface on which the creep control fluid pressure for applying the creep control torque selectively acts is formed, and the pressing force by the starting fluid pressure on the pressure receiving surface is greater than the pressing force by the creep control fluid pressure. A starting clutch device for an automatic transmission, which is configured to be large.