JPH10131984A - Locking device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To positively prevent the generation of inappropriate locking force caused by centrifugal pressure so as to make locking action smooth by communicating an operating fluid pressure device and a centrifugal fluid pressure chamber by an orifice, and making low fluid pressure act upon the centrifugal oil pressure chamber through a pressure regulating valve. SOLUTION: In the lock released state of a high clutch H/C, an operating oil pressure chamber 20 communicates with the drain side. At this time, low pressure oil is fed to the operating oil pressure chamber 20 from a centrifugal oil pressure chamber 24 via an orifice 25 provided at a piston 15, and the chamber 20 is always filled with oil. A small quantity of oil fed to the centrifugal oil pressure chamber 24 via the orifice 25 is fed by that portion from an unillustrated pressure regulating valve so as to fill the operating oil pressure chamber 20, and discharged to the drain side in the end. Accordingly, even in case of air being mixed into the centrifugal oil pressure chamber 24 or the operating oil pressure chamber 20, this air is exhausted to the drain side in association with the flow of oil to the drain side. The centrifugal oil pressure chamber 24 is therefore held positively in the state of being constantly filled with oil so as to be able to offset centrifugal oil pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic fastening device such as a clutch or a brake in an automatic transmission, which reliably prevents generation of an improper fastening force due to a so-called centrifugal pressure and realizes a smooth fastening operation. The present invention relates to a fastening device for an automatic transmission that can be realized.

[0002]

2. Description of the Related Art Generally, as an automatic transmission for a vehicle,
2. Description of the Related Art It has become widespread to input the rotation of an engine via a torque converter, change the speed by a transmission mechanism having a plurality of planetary gear sets, and output the speed to a propeller shaft (axle side). A transmission mechanism in this type of automatic transmission transmits the rotation of the input shaft from the torque converter to a specific gear or carrier that constitutes a planetary gear according to the shift position, or controls the rotation of the specific gear or carrier. To transmit power to the output shaft as appropriate, or to restrict the rotation of a specific gear or carrier as appropriate,
Usually, a plurality of hydraulic fastening devices such as clutches and brakes are provided.

[0003] This fastening device exerts a fastening force when a normally hydraulically driven piston is pressed against, for example, a multi-plate type fastening element, and releases the oil by discharging the oil from the cylinder. However, because oil discharge from the cylinder relies on gravity falling naturally,
In addition, since the piston and the cylinder that slidably supports the piston are generally rotated together with the driving element or the driven element to be fastened, part of the oil in the cylinder is centrifugal even when the oil is discharged. As a result, a pressure due to centrifugal force (hereinafter, referred to as centrifugal pressure or centrifugal hydraulic pressure) is generated in the working hydraulic chamber even at the time of release of the fastening, thereby hindering the gear shifting operation. There are cases. That is, when the centrifugal oil pressure is generated, the piston operates correspondingly to the fastening element to generate a considerable fastening force. For this reason, a fastening force is generated even when it is not time to perform the fastening, and in some cases, an appropriate shift operation cannot be performed.

Therefore, conventionally, for example, Japanese Patent Application Laid-Open No. Sho 62-52
As disclosed in Japanese Patent Publication No. 249, a so-called centrifugal oil pressure cancel chamber is provided, or a so-called drift-on ball for draining oil is provided on the outer peripheral side of a cylinder or the like to prevent centrifugal oil pressure. Here, the centrifugal oil pressure cancel chamber is formed so as to face the piston on the opposite side of the working oil pressure chamber, and generates a force due to centrifugal oil pressure of the same size as the working oil pressure chamber and in the opposite direction. By doing so, the force due to the centrifugal hydraulic pressure in the working hydraulic chamber is canceled out, thereby trying to prevent the pressing force of the piston due to residual oil, that is, the generation of the fastening force of the fastening device. Also, the drift-on ball is loaded into the oil drain hole provided in the piston,
When a hydraulic pressure is applied to the working hydraulic chamber, the pressure moves to the small diameter side of the oil drain hole by the pressure to close the oil drain hole,
When the piston or the cylinder idles in a state where no oil pressure is applied, the centrifugal force moves the piston or the cylinder to the outer peripheral portion on the large diameter side of the oil drain hole to open the oil drain hole. The oil in the chamber is drained from the oil drain hole to prevent the generation of centrifugal oil pressure.

[0005]

However, the conventional countermeasures against centrifugal hydraulic pressure are not enough to reliably prevent the generation of inappropriate fastening force due to centrifugal hydraulic pressure and to realize a smooth fastening operation. Was. This is because if the centrifugal oil pressure cancel chamber is not filled with oil at the beginning of operation of the automatic transmission or the like simply by simply providing the centrifugal oil pressure cancel chamber and connecting it to the hydraulic power source, The centrifugal oil pressure cannot be canceled. For this reason, generation of an inappropriate fastening force due to centrifugal hydraulic pressure cannot always be reliably prevented. In addition, when a drift-on ball is provided, it takes some time from the time when hydraulic pressure is applied to the working hydraulic chamber to the time when the drift-on ball moves to a position to open the oil drain hole, There is a limit in improving control responsiveness, which is an obstacle to achieving a smoother fastening operation.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fastening device for an automatic transmission that can reliably prevent generation of an inappropriate fastening force due to centrifugal pressure and can realize a smooth fastening operation.

[0007]

In order to achieve the above object, a fastening device for an automatic transmission according to the present invention is operated by being pressed by a hydraulically operated piston, so that a driving element and a driven element are connected to each other. A cylinder for slidably fitting the piston, and a piston and the cylinder formed on one side of the piston for operating the piston in the direction of pressing the fastening element. A hydraulic pressure chamber to which a high hydraulic pressure is supplied, a centrifugal hydraulic chamber formed at the other side of the piston by a partition fixed to the piston and the cylinder, and supplied with a low hydraulic pressure, An orifice for communicating the working hydraulic chamber and the centrifugal hydraulic chamber includes a hydraulic pressure supply circuit for applying a low hydraulic pressure to the centrifugal hydraulic chamber via a pressure regulating valve.

According to a second aspect of the invention, there is provided a fastening device for an automatic transmission.
The orifice is arranged on the inner diameter side of the piston.

According to a third aspect of the present invention, there is provided a fastening device for an automatic transmission.
A fastening element that is activated by being pressed by a hydraulically actuated piston, and that can connect the driving element and the driven element;
A cylinder for slidably fitting the piston therein, and a high hydraulic pressure for forming the piston and the cylinder on one side of the piston for operating the piston in the pressing direction of the fastening element are supplied. A hydraulic fluid chamber, and a centrifugal fluid pressure chamber formed on the other side of the piston with a partition fixed to the piston and the cylinder and supplied with a low fluid pressure. A hydraulic pressure supply circuit for applying a low hydraulic pressure via a pressure regulating valve, and interrupting a flow of hydraulic fluid from the hydraulic hydraulic chamber to the centrifugal hydraulic chamber, and from the centrifugal hydraulic chamber to the hydraulic hydraulic chamber. Characterized in that it has a one-way hydraulic mechanism for passing the hydraulic fluid.

[0010] According to a fourth aspect of the present invention, there is provided a fastening device for an automatic transmission.
The one-way hydraulic mechanism is constituted by a tapered hole formed in the piston, and a ball that closes the tapered hole to block the flow of hydraulic fluid from the hydraulic hydraulic chamber to the centrifugal hydraulic chamber. The tapered surface on the outer peripheral side of the piston in the tapered hole is parallel to a rotation axis of the fastening element.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. First Example First, a first example of the invention according to claim 1 or 2 is described.
An example will be described with reference to FIGS. FIG. 1 is a sectional view of a main part of the automatic transmission according to the present embodiment, and FIG. 2 or FIG.
Fastening device (high clutch H / C) in the automatic transmission
It is a figure which shows each hydraulic-pressure supply circuit. FIG. 4 is a diagram illustrating a skeleton of a transmission mechanism that constitutes the automatic transmission according to the present embodiment. FIG. 5 is a diagram illustrating an operation state according to a shift position of each fastening device in the automatic transmission according to the present embodiment. For convenience, in FIG. 1 or FIG. 4, the left side (engine side) is the front side, and the right side (far side from the engine) is the rear side.

(A) Overall Configuration of Transmission Mechanism First, referring to FIGS. 4 and 5, the overall configuration of the transmission mechanism of the automatic transmission according to the present embodiment will be described. In addition, the automatic transmission of this example is
In addition to the transmission mechanism shown in FIG. 4, a torque converter, an oil pump, a control valve unit, a control unit and the like having a well-known configuration are provided, but illustration and detailed description of these components are omitted.

As shown in FIG. 4, the transmission mechanism includes an input shaft 1, an output shaft 2, a first planetary gear 3, a second planetary gear 4, a high clutch (H / C), a reverse clutch (R / C) 2-4 brake (2-4 / B), low clutch (L / C), low one-way clutch (LO / C), low reverse brake (LR / B).

Here, a high clutch (H / C), a reverse clutch (R / C) and a 2-4 brake (2-4 /
B), the low clutch (L / C), and the low reverse brake (LR / B) are of a hydraulically actuated multi-plate type,
A plurality of torque transmitting elements including a drive plate and a driven plate are arranged in parallel, thereby connecting and disconnecting a predetermined torque transmission larger than the transmission torque capacity of each transmission element. High clutch (H
/ C) has a function of connecting the input shaft 1 and the first carrier C1, and has a reverse clutch (R /
C) has a function of connecting the input shaft 1 and the first sun gear S1. In addition, high clutch (H / C)
The present invention is applied, and the detailed configuration of the high clutch (H / C) and the reverse clutch (R / C) will be described later with reference to FIG.

The low clutch (L / C) has a function of directly connecting the first carrier C1 and the second ring gear R2. The low reverse brake (LR / B) is provided with a transmission case K and a low one-way clutch (LO / B).
It has a function of generating a frictional engagement force with the outer race C) to exert a braking force on the first carrier C1. The low one-way clutch (LO / C) is, for example, a sprag type, and makes only the rotation of the first carrier C1 in the normal rotation direction (the same rotation direction as the engine) free and restricts the reverse rotation. In addition, 2-4 brake (2-
4 / B) applies a braking force to the first sun gear S1.

In the above-mentioned transmission mechanism, hydraulic oil is appropriately supplied to a working chamber of a piston for driving each fastening element by control of a control unit and a control valve unit (not shown), and as shown in FIG. Operates as follows. First, when the select lever is in the D range, the control unit receives a vehicle speed signal based on a vehicle speed sensor, a throttle opening signal from a throttle sensor or the like mounted on an engine of the vehicle, and the like, and sets a predetermined shift characteristic. Determine the shift position (1st to 4th speed) based on the pattern,
A predetermined clutch or brake is operated according to each shift position as shown in FIG.

That is, at the first speed, the low clutch (L /
C) is operated unconditionally, and the low reverse brake (LR / B) is operated when predetermined operating conditions are satisfied. At this time, row one way clutch (LO / C)
Operates in an accelerated state. Thereby, the driving force of the input shaft 1 during acceleration is transmitted to the second pinion gear P2 via the second sun gear S2, and the rotation of the second sun gear S2 in a state where the reverse rotation of the second ring gear R2 is prevented. As the revolution of the second pinion gear P2 (the revolution of the second carrier C2), the torque is greatly amplified (decelerated) to the output shaft 2 and output.

When the low reverse brake (LR / B) is inactive, the reverse driving force from the output shaft 2 during deceleration is reduced by the action of the low one-way clutch (LO / C). Gear R2
Is not transmitted to the input shaft 1 and the so-called engine brake does not work.
Shifting down to high speed is also performed smoothly without shock. On the other hand, when the low reverse brake (LR / B) is in operation, idling of the second ring gear R2 in the forward rotation direction is also prevented, so that the reverse driving force is transmitted to the input shaft 1 and the so-called engine The brake works. The operating conditions of the low reverse brake (LR / B) are such that a special mode such as a power mode is set for the control unit by a power switch provided on a select lever, and the accelerator opening is equal to or less than a predetermined value. Is the case.

Next, in the second speed, the low clutch (L / C)
And 2-4 brake (2-4 / B) are operated unconditionally. Thus, the input shaft 1 during acceleration
Is transmitted to the second pinion gear P2 via the second sun gear S2 to rotate the second carrier C2 and the first ring gear R1 at the same speed. On the other hand, since the first sun gear S1 is fixed by the 2-4 brake (2-4 / B), the first carrier C1 and the low clutch (L / C) are moved with the rotation of the first ring gear R1. And the second ring gear R2 connected thereto rotates forward. Accordingly, as a result, the driving force of the input shaft 1 during acceleration is increased by the rotation of the second ring gear R2 as compared with the case of the first speed, and the revolution of the second pinion gear P2 (the positive rotation of the second carrier C2). As a result, the torque is amplified (decelerated) to some extent by the output shaft 2 and output. And
The reverse driving force from the output shaft 2 at the time of deceleration is prevented by the operation of the low clutch (L / C), so that the idle rotation of the second ring gear R2 with respect to the first carrier C1 is prevented. Conveyed,
The so-called engine brake works.

Next, at the third speed, the high clutch (H / C)
And the low clutch (L / C) are operated unconditionally. As a result, the driving force of the input shaft 1 during acceleration is
The high clutch (H / C), the first carrier C1, the low clutch (L / C) and the second ring gear R are transmitted to the second pinion gear P2 via the second sun gear S2.
2 is also transmitted to the second pinion gear P2, and as a result, is transmitted to the output shaft 2 as the revolution of the second pinion gear P2 (the rotation of the second carrier C2), and the speed ratio becomes 1. That is, during acceleration, the output shaft 2 rotates integrally with the input shaft 1. The reverse driving force from the output shaft 2 during deceleration is equal to the low clutch (L
/ C) prevents idle rotation of the second ring gear R2 with respect to the first carrier C1, so that the reverse driving force is transmitted to the input shaft 1 and a so-called engine brake is applied.

In the fourth speed, a high clutch (H / C)
And the 2-4 brake (2-4 / B) are operated unconditionally. Thereby, the driving force of the input shaft 1 during acceleration is transmitted to the output shaft 2 via the high clutch (H / C), the first carrier C1, the first pinion gear P1, the first ring gear R1, and the second carrier C2. Is transmitted.
As a result, the rotation of the input shaft 1 during acceleration is caused by the rotation of the first pinion gear P with the first sun gear S1 stopped.
As the rotation of the first ring gear R <b> 1 (the rotation of the second carrier C <b> 2) accompanying the rotation of No. 1, the speed is increased and output to the output shaft 2. The reverse driving force from the output shaft 2 at the time of deceleration is always transmitted to the input shaft 1 because the driving force is not transmitted through the one-way clutch, so that a so-called engine brake operates.

Next, when the select lever is operated to the R range, the reverse clutch (R / C) and the low reverse brake (LR / B) operate unconditionally. Then, the driving force of the input shaft 1 is changed to the reverse clutch (R /
C) to the first sun gear S1, and the first ring gear R1 accompanying the rotation of the first sun gear S1 in a state where the first carrier C1 (revolution of the first pinion gear P1) is stopped.
(Reverse rotation of the second carrier C2), the rotation direction is reversed to the output shaft 2 and the torque is amplified (decelerated) and output. Therefore, the vehicle can be moved backward.

(B) Detailed Configuration of Principal Part Next, the detailed configuration of the principal part to which the invention of claim 1 or 2 is applied will be described with reference to FIGS. (A) Configuration of Mechanical Section such as High Clutch H / C First, the configuration of the mechanical section will be described with reference to FIG. In the present embodiment, the present invention is applied to a clutch device constituting a high clutch (H / C). And FIG.
FIG. 2 is a partial cross-sectional view of the transmission mechanism of the automatic transmission according to the present embodiment, around a portion where the high clutch (H / C) is provided. In this case, the upper half of the center axis 1a of the hollow input shaft 1 is shown. Is shown. High clutch (H /
C) is a driven plate 1 connected to a drum 11 (drive element, cylinder) by a spline as shown in FIG.
2 (fastening element) and a drive plate 14 (fastening element) connected by a spline to a hub 13 (driven element), which is a multi-plate type in which the piston slides left and right in FIG. The drum 11 and the hub 13 are connected by the frictional force generated when each plate is pressed in the close contact direction by 15.

Here, the drum 11 is mounted on the transmission case K
A bearing 17 supports a fixed boss member 16 provided in a fixed state (not shown in FIG. 1), and is rotatable around the central axis 1a. The drum 11 has an inner peripheral portion 11a having a minimum diameter.
, Is spline-connected to the input shaft 1 and rotates integrally with the input shaft 1.
The hub 13 is mounted on the inner peripheral side of the drum 11 and the input shaft 1 with the bearings 18 and 1 shown in FIG.
9 and is rotatable about the center axis 1a as a center of rotation. Although not shown in FIG. 1, the hub 13 is connected to the first carrier C1 of the first planetary gear 3 at the rear end, and
It rotates integrally with the carrier C1. Therefore,
After all, the high clutch H / C has a function of connecting the input shaft 1 and the first carrier C1 as described above.

In this case, the piston 15 slides as a cylinder between a piston 35 and a drum 11 of a reverse clutch (R / C), which will be described later, and a working hydraulic chamber formed between the piston 35 and the piston 15. 20 (hydraulic pressure chamber) is supplied with pressure oil via an oil passage 21 formed in the inner peripheral side cylindrical portion 11b of the drum 11 and the fixed boss member 16 to move to the operating position, and the spring is moved. 22
To the inoperative position by the restoring force of. In this case, the spring 22 is interposed in a compressed state between a later-described partition 23 and the piston 15. On the rear side of the piston 15 in the inner peripheral cylindrical portion 11b of the drum 11, a partition 2 is provided.
3 is fixedly mounted, and the partition wall 23 and the piston 1
A centrifugal hydraulic chamber 24 (centrifugal hydraulic chamber) for canceling the centrifugal hydraulic pressure in the working hydraulic chamber 20 is formed between the hydraulic hydraulic chamber 5 and the hydraulic hydraulic chamber 20. That is, the pressure receiving area of the piston 15 with respect to the working hydraulic chamber 20 and the pressure receiving area with respect to the centrifugal hydraulic chamber 24 are set substantially equal. In addition, an orifice 25 that connects the working hydraulic chamber 20 and the centrifugal hydraulic chamber 24 is formed on the inner diameter side of the piston 15 in this case. The centrifugal hydraulic chamber 24 is supplied with a pressure from a hydraulic supply circuit 100 including a pressure regulating valve 110, which will be described later, via an oil passage 26 formed in the inner peripheral cylindrical portion 11b of the drum 11 and the fixed boss member 16. Oil is supplied.

As shown in FIG. 1, the reverse clutch (R / C) is formed by alternately stacking a driven plate 32 connected to the drum 11 by a spline and a drive plate 34 connected to a hub 33 by a spline. The drum 11 and the hub 33 are connected by a frictional force generated when each plate is pressed in the contact direction by a piston 35 sliding left and right in FIG.

Here, the drum 11 is spline-connected to the input shaft 1 as described above, and rotates integrally with the input shaft 1. The hub 33 is
The hub 13 is supported by the bearing 38 shown in FIG. 1 and the like, and is rotatable around the central axis 1a. Although not shown in FIG. 1, the hub 33 is connected to the first sun gear S1 of the first planetary gear 3 at the rear end, and rotates together with the first sun gear S1. Therefore, the reverse latch R / C has a function of connecting the input shaft 1 and the first sun gear S1 as described above.

In this case, the piston 35 slides using the drum 11 as a cylinder, and a piston 1 is inserted into a working hydraulic chamber 40 formed between the drum 11 and the piston 35.
The pressure oil is supplied through an oil passage 41 formed in the inner peripheral side cylindrical portion 11b and the fixed boss member 16 to move to the operation position, and returns to the non-operation position by the restoring force of the spring 22. I do. The force by which the piston 35 presses each plate is received by a snap ring 51 attached to the rear end of the cylindrical portion on the outer peripheral side of the drum 11. Is pinched to generate a fastening force.

The high clutch H is provided inside the rear end of the piston 35 pressing each plate.
A snap ring 52 for receiving the pressing force of the piston 15 of / C is attached. As a result, when the piston 35 moves to the rear side when the reverse latch R / C is actuated, the piston 35 is pushed by the piston 35 to move the piston 15 of the high clutch H / C.
The snap ring 52 also moves by the same stroke with the movement of the piston 35, so that hydraulic pressure is applied to the working hydraulic chamber 20 and the piston 15 moves relative to the piston 35. Unless the high clutch H / C is operated, the pistons 15 and 35 function independently.

In addition, an oil drain hole 61 is formed on the outer diameter side of the piston 15 in order to communicate the working hydraulic chamber 40 with the internal space of the mechanism that is at atmospheric pressure.
Is mounted with a so-called drift-on ball 62. As described in the section of the prior art, when the hydraulic pressure is applied to the working hydraulic chamber 40, the drift-on ball moves to the small diameter side of the oil drain hole 61 due to the pressure and closes the oil drain hole 61. Then, when the hydraulic pressure is not applied, the piston 3
When the drum 5 idles with the drum 11, the centrifugal force causes the oil drain hole 61 to move to the outer peripheral portion on the large-diameter side, and this oil drain hole
1 to release the oil in the working hydraulic chamber 40 from the oil drain hole 61 when the fastening device is released, thereby preventing the generation of centrifugal hydraulic pressure.

As described above, the drift-on ball has a disadvantage that the response during operation is not good.
Reverse clutch R driven by this piston 15
As described above, / C operates only when the vehicle is moving backward and is not used for shifting during forward movement, so this disadvantage is not a problem.

(B) Configuration of Hydraulic Circuit of High Clutch H / C Next, the configuration of the hydraulic circuit of the high clutch H / C will be described with reference to FIGS. First, high clutch H /
C hydraulic pressure supply circuit 10 for supplying pressure oil to centrifugal hydraulic chamber 24
0 will be described. FIG.
The pressure regulating valve 110 schematically shown in FIG.

The pressure regulating valve 110 is built in, for example, a control valve unit, and has an input port 111.
, An output port 112, a drain port 113, and a feedback port 114. When the spool 115 moves to the left in FIG.
When the return force of the return spring 116 overcomes the pressure of the feedback port 114 and the spool 115 moves to the right as shown in FIG. 2, the input port 111 and the output port 112 are connected. A low pressure such as a lubricating pressure P _LUB is applied to the input port 111, and the output port 112 is connected to the centrifugal hydraulic chamber 24 via the oil passage 26,
Is connected to a drain line communicating with an oil pan (not shown), and the feedback port 114 is connected to an output port 112 via a feedback oil passage 117.

In a general automatic transmission, the lubricating pressure _PLUB is the same as the operating pressure of the normal torque converter, and the pressure oil whose oil pump discharge pressure has been reduced by a torque converter relief valve (not shown) is used to reduce the torque. Although it is used both for converter operation and for lubrication, in this example, for example, this lubricating pressure _{PLUB is used} for the centrifugal hydraulic chamber 2.
It is used as the original pressure applied to 4. Further, according to the pressure regulating valve 100, the smaller the restoring force of the return spring 116 is set, the more the pressure of the output port 112 is reduced.
That is, although the pressure applied to the centrifugal hydraulic chamber 24 can be adjusted to a small value, it is preferable that the set value of the output pressure be set to the minimum necessary value that allows the centrifugal hydraulic chamber 24 to be constantly filled with oil.

Next, the working hydraulic chamber 2 of the high clutch H / C
The hydraulic pressure supply circuit 200 that supplies pressure oil to zero will be described. The hydraulic supply circuit 200 includes an amplifier valve 210 schematically shown in FIG. The amplifier valve 210 is incorporated in, for example, a control valve unit, and includes an input port 211, an output port 212, a drain port 2
13, a feedback port 214, and a pilot port 215. When the spool 216 moves to the left in FIG. 3 by the pressure of the pilot port 215, the input port 211 and the output port 212 communicate with each other, and the restoring force of the return spring 217 and When the pressure of the feedback port 214 overcomes the pressure of the pilot port 215 and the spool 216 moves to the right as shown in FIG. 3, the output port 212 and the drain port 213 are connected. Then, the input port 111, lubricant pressure P _LUB from a high so-called line pressure P _L of the above is added,
The output port 212 is connected to the working hydraulic chamber 20 via the above-described oil passage 21, the drain port 213 is connected to a drain line communicating with an oil pan (not shown), and the feedback port 214 is connected to the feedback oil passage 218.
The pilot port 215 is connected to the output port 212 via a so-called duty solenoid valve (not shown).

In a general automatic transmission, the line pressure P _L is obtained by adjusting the discharge pressure of an oil pump according to a traveling state by a pressure regulator valve (not shown) or the like. The duty cycle of the duty solenoid valve is controlled by a control unit (not shown), whereby the pilot pressure applied to the pilot port 215 at the timing when the high clutch H / C is to be operated increases from the atmospheric pressure. When the engaged state of the high clutch H / C is released, the pressure is adjusted to return to the atmospheric pressure.

(C) Operation of High Clutch H / C and Its Hydraulic Circuit Next, the operation of the high clutch H / C and its hydraulic circuit configured as described above will be described. First, when the control unit determines that it is time to operate the high clutch H / C to increase the engagement force, and controls the duty cycle of the duty solenoid valve to increase the pilot pressure applied to the pilot port 215, the hydraulic supply circuit 200 Then, the force due to the pressure of the pilot port 215 overcomes the urging force of the spring 217 and the force due to the pressure of the feedback port 214, and the spool 216 moves to the left in FIG. 3 according to the magnitude of the pilot pressure. The input port 211 communicates with a large channel area. Therefore, according to the duty cycle of the duty solenoid valve, the source pressure is applied to the working hydraulic chamber 20 communicating with the output port 112 by the line pressure P.
_The pressure oil having a predetermined pressure of _L is supplied and the high clutch H
/ C operates with the fastening force according to the control of the control unit. At this time, although the oil slightly leaks from the orifice 25 provided in the piston 15 to the centrifugal hydraulic chamber 24,
Since it is slight, it does not affect the operation of the high clutch H / C.

Conversely, when the control unit determines that it is time to reduce the engaging force of the high clutch H / C and controls the duty cycle of the duty solenoid valve to reduce the pilot pressure applied to the pilot port 215, the hydraulic pressure In the supply circuit 200, the force due to the pressure at the pilot port 215 is less than the force due to the urging force of the spring 217 and the force due to the pressure at the feedback port 214, and the spool 216 according to the magnitude of the pilot pressure.
Move to the right in FIG. 3, and the output port 212 communicates with the drain port 213 with a larger flow area. Therefore, the pressure in the working hydraulic chamber 20 communicating with the output port 212 is reduced according to the duty cycle of the duty solenoid valve. FIG. 2 shows the spool 216
Indicates the state where the output port 212 communicates with the drain port 213 with the largest opening area.
Thus, in the working hydraulic chamber 20 of the high clutch H / C,
The hydraulic source pressure to control exactly the control unit by the supply circuit 200 is supplied with pressurized oil at the line pressure P _L, or the oil is overtaken drain side, in this embodiment the shift-up to for example second gear to the third gear , The pressure is increased and, for example, in a downshift from third gear to second gear, the pressure is reduced to atmospheric pressure.

On the other hand, in the hydraulic supply circuit 100, the oil passage 26
When the pressure at the output port 112 of the pressure regulating valve 110 connected to the centrifugal hydraulic chamber 24 through the above-mentioned pressure exceeds the extremely low pressure set pressure described above, the force of the feedback port 114 overcomes the urging force of the spring 116. The spool 115 moves to the left in FIG. 2 according to its size, and connects the output port 112 to the drain port 113 with a larger flow area. Therefore, as the pressure exceeds the set pressure, the centrifugal hydraulic chamber 2 communicating with the output port 112
The pressure of 4 is reduced faster. Conversely, when the pressure at the output port 112 falls below the extremely low pressure set pressure described above, the force due to the pressure at the feedback port 114 loses the urging force of the spring 116, and the spool 115 moves according to the magnitude of the force. At the right side to make the output port 112 communicate with the input port 111 with a larger flow area. For this reason, the pressure of the centrifugal hydraulic chamber 24 communicating with the output port 112 is increased more quickly as the pressure is reduced from the set pressure. FIG. 2 shows a state in which the spool 115 moves to the rightmost side and the output port 112 communicates with the input port 111 with the largest opening area.

For this reason, according to the hydraulic supply circuit 100, the pressure in the centrifugal hydraulic chamber 24 is constantly maintained at the set pressure, and the pressure in the centrifugal hydraulic chamber 24 fluctuates from the set pressure due to some factor. Also, a function of returning the pressure to the set pressure is exhibited. As a result, as long as the engine of the vehicle is operating and the oil pump is operating, the centrifugal hydraulic chamber 24 is kept in a state where a low pressure near the set pressure is constantly applied, and the function of canceling the centrifugal hydraulic pressure described above is provided. Demonstrated reliably at all times.

That is, for example, the operating hydraulic chamber 2 is released under the control of the control unit in order to release the engagement of the high clutch H / C by the operation of the hydraulic supply circuit 200 described above.
When the oil of 0 is drained to the drain side, and the piston 15 retreats and the volume of the centrifugal hydraulic chamber 24 increases, the hydraulic oil whose original pressure is the lubricating pressure P _LUB is quickly generated by the operation of the hydraulic supply circuit 100. Centrifugal hydraulic chamber 24 is supplied to centrifugal hydraulic chamber 24
The pressure of No. 4 is maintained near the set pressure, and the centrifugal hydraulic chamber 24 is maintained in a state of being filled with oil. The oil source pressure to the working pressure chamber 20 is a line pressure P _L under the control of the control unit to actuate the engagement of high clutch H / C is supplied by the action of the hydraulic pressure supply circuit 200 described above, the piston 15 moves forward When the volume of the centrifugal hydraulic chamber 24 decreases, the oil in the centrifugal hydraulic chamber 24 is promptly drained to the drain side by the action of the hydraulic supply circuit 100, and the pressure of the centrifugal hydraulic chamber 24 also becomes close to the set pressure. The centrifugal hydraulic chamber 24 is held in a state filled with oil.

Further, since the centrifugal hydraulic chamber 24 is always filled with the oil of the predetermined set pressure as described above, the engagement of the high clutch H / C is released, that is, through the hydraulic supply circuit 200. By control of the control unit,
Even when the working hydraulic chamber 20 communicates with the drain side, the oil in the centrifugal hydraulic chamber 24 is supplied to the working hydraulic chamber 20 via the orifice 25 provided in the piston 15, and as a result, the working hydraulic chamber 20 is always The oil is filled. At this time, a small amount of oil supplied from the centrifugal hydraulic chamber 24 to the working hydraulic chamber 20 via the orifice 25 is supplied from the hydraulic supply circuit 100 by that amount to fill the working hydraulic chamber 20 with oil. Finally, it is discharged from the working hydraulic chamber 20 to the drain side via the hydraulic supply circuit 200.
For this reason, even if air enters the centrifugal hydraulic chamber 24 or the working hydraulic chamber 20 when the high clutch H / C is in the disengaged state, this air passes from the centrifugal hydraulic chamber 24 through the working hydraulic chamber 20. With the flow of the oil to the drain side, the oil is finally exhausted to the drain side via the drain port 213 of the hydraulic pressure supply circuit 200. In particular, in this case, since the orifice 25 is provided on the inner diameter side of the piston 15, the effect of exhausting the mixed air is particularly remarkably exhibited. Because in this case the piston 15
Due to the centrifugal force caused by idling, oil with less air mixed therein flows to the outer peripheral side, and the mixed air easily moves to the inner peripheral side of the centrifugal hydraulic chamber 24 and the like, so that the mixed air passes through the orifice 25 immediately. The oil is finally discharged from the drain port 213 of the hydraulic supply circuit 200 by the flow of the oil.

Therefore, according to the fastening device including the high clutch H / C and the hydraulic pressure supply circuits 100 and 200 of the present embodiment, the following excellent effects can be obtained. (1) First, since the centrifugal hydraulic chamber 24 is always filled with oil, the centrifugal hydraulic pressure generated in the working hydraulic chamber 20 generates an engaging force even when the high clutch H / C is not engaged, and the high clutch H / C It is possible to prevent a problem in which each plate constituting C is so-called dragged and wears each plate without fail, with much higher reliability than before. This is because, in the conventional configuration in which the oil supply source is simply communicated with the centrifugal hydraulic chamber and the oil is supplied to the centrifugal hydraulic chamber by centrifugal force, the oil cannot be supplied immediately when the engine is started. The centrifugal hydraulic chamber 24 cannot always be filled with oil because air is likely to be mixed in. However, in this example, a part of the pressure of the oil pump is positively applied. Is quickly exhausted through the orifice 25, so that the centrifugal hydraulic chamber 24 is always kept in a state of being filled with oil,
The centrifugal oil pressure can be surely offset.

(2) Even when the high clutch H / C is not operated, the working hydraulic chamber 20 is filled with oil, and the air mixed in the working hydraulic chamber 20 is filled with the orifice 25.
, The oil is quickly exhausted by the flow passing through, so that it is not necessary to pour the oil into the operating hydraulic chamber 20 and release the air at the start of the operation of the high clutch H / C.
0 only closes the drain port 213 and the hydraulic pressure chamber 2
The oil pressure of 0 immediately rises to the oil pressure equivalent to that of the centrifugal oil pressure chamber 24, and the responsiveness when the high clutch H / C operates is remarkably improved. For this reason, in this example, there is an effect that the operation of upshifting from the second speed to the third speed becomes extremely smooth, for example. When the piston 15 advances at the start of the operation of the high clutch H / C, the oil in the centrifugal hydraulic chamber 24 is quickly discharged by the operation of the hydraulic supply circuit 100 as described above. The response does not deteriorate due to the delay.

(3) Further, since a low pressure always acts on the centrifugal hydraulic chamber 24 and the force due to this pressure also functions as a restoring force of the piston 15, when the engagement of the high clutch H / C is released, the working hydraulic chamber 20 is released. Oil is quickly discharged and piston 1
5 quickly retreats. For this reason, in this example, for example, 3
There is also an effect that the operation of downshifting from the high speed to the second speed becomes extremely smooth. Therefore, the high clutch H / C of this example
Operates promptly and reliably as controlled by the control unit via the hydraulic supply circuit 200. For example, in the upshift from the second speed to the third speed, the fastening force is smoothly increased and the predetermined fastening force is increased. And, for example, in a downshift from the third speed to the second speed, the fastening force is smoothly reduced and the fastening state is reliably released.

Second Example Next, a second example, which is an example of the third aspect of the present invention, will be described with reference to FIG. FIG. 6 is a sectional view of a main part of the automatic transmission according to the present embodiment. In this embodiment, the one-way hydraulic action mechanism 3 is applied to the piston 15 of the clutch H / C in the first embodiment.
The second embodiment is characterized in that it is provided with 00, and the other configuration is the same as that of the first example. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 6, the one-way hydraulic action mechanism 300 operates by closing the tapered hole 301 formed in the piston 15 and connecting the working hydraulic chamber 20 and the centrifugal hydraulic chamber 24 to each other. And a ball 302 that blocks the flow of oil from the hydraulic chamber 20 to the centrifugal hydraulic chamber 24. Here, the tapered hole 301 has a tapered step in the middle, a large-diameter portion on the front side (the hydraulic pressure chamber 20 side) of the step, and a rear side (centrifugal hydraulic chamber) of the step. 24) is formed with a small diameter portion. The ball 302 is loaded in the large diameter portion of the tapered hole 301 and closes the tapered hole 301 by sitting on the tapered step.

According to the structure of this embodiment, the following effects are obtained in addition to the effects similar to those of the first embodiment. That is, in this example, the flow of oil from the working hydraulic chamber 20 to the centrifugal hydraulic chamber 24 is cut off by the operation of the one-way hydraulic action mechanism 300, so that when the high clutch H / C is operated, the operating hydraulic chamber 2
Oil does not leak from 0 to the centrifugal hydraulic chamber 24, the consumption of oil is reduced, and the discharge flow rate of the oil pump can be saved. Further, the pressure in the working hydraulic chamber 20 is increased more quickly, and the responsiveness of the operation of the high clutch H / C can be further improved.

Third Example Next, a third example, which is an example of the fourth aspect of the present invention, will be described with reference to FIGS. FIG. 7 is a cross-sectional view of a main part of the automatic transmission according to the present embodiment, and FIG. 8 is a diagram illustrating an operation effect of the one-way hydraulic operation mechanism according to the embodiment. This embodiment is similar to the piston 15 of the clutch H / C in the first embodiment.
Is characterized in that a one-way hydraulic action mechanism 400 is provided, and other configurations are the same as those in the first example.
The same components are denoted by the same reference numerals, and the description is omitted.

As shown in FIG. 6, the one-way hydraulic action mechanism 400 operates by closing the tapered hole 401 formed in the piston 15 and connecting the working hydraulic chamber 20 and the centrifugal hydraulic chamber 24 to each other. And a ball 402 that blocks the flow of oil from the hydraulic chamber 20 to the centrifugal hydraulic chamber 24. Here, the tapered hole 401 has a tapered step in the middle part, similarly to the tapered hole 301 of the above-described second example, and the front side of the step (the hydraulic pressure chamber 20).
A large diameter portion is formed at the rear side (the side of the centrifugal hydraulic chamber 24) of the step portion, and the small diameter portion is formed at the rear side of the step portion. The entire axis is inclined with respect to the rotation axis 1a, and as a result, as shown in FIG.
Is parallel to the rotation axis 1a. The ball 402 is loaded in the large diameter portion of the tapered hole 401 and closes the tapered hole 401 by sitting on the tapered step.

According to the structure of this embodiment, the following effects are obtained in addition to the same effects as those of the second embodiment. That is, in the one-way hydraulic action mechanism 300 in the second example, when the ball 302 moves from the non-blocking position indicated by the solid line in FIG. Since the ball 302 receives the force, the magnitude of the hydraulic pressure at which the ball 302 moves to the closing position differs depending on the rotation speed of the piston 15. You will be late. However, in this example, when the ball 402 moves from the non-closed position shown by the solid line in FIG. 8B to the closed position shown by the dashed line, the ball 402 is moved in the lateral direction and does not receive resistance due to centrifugal force. For this reason, the magnitude of the hydraulic pressure at which the ball 402 moves to the closing position becomes constant irrespective of the rotation speed of the piston 15, and the ball 402 easily moves to the closing position irrespective of the rotation speed. It will be done promptly. For this reason, the effect of saving the oil amount and the effect of improving the responsiveness of the operation of the high clutch H / C are more remarkable.

Fourth Example Next, a fourth example according to another embodiment of the present invention will be described.
An example will be described with reference to FIG. FIG. 9 is a cross-sectional view of a main part of the automatic transmission according to the present embodiment. This embodiment is characterized in that the spring 22 for applying a restoring force to the piston 15 of the clutch H / C in the first embodiment is eliminated, and the other configuration is the same as that of the first embodiment. The same components are denoted by the same reference numerals, and description thereof is omitted.

In this example, by setting the set pressure of the pressure regulating valve 110 of the hydraulic supply circuit 100 to be slightly higher,
When the high clutch H / C is disengaged, the piston 15 is pushed back to the inoperative position only by the force of the hydraulic pressure in the centrifugal hydraulic chamber 24. According to the configuration of this example, in addition to the same effects as in the first example, there is an effect that the cost can be reduced and the size can be reduced by the elimination of the spring 22.

The present invention is not limited to the embodiments described above, but may have various aspects or applications. For example, the present invention can be applied not only to the clutch device but also to a hydraulic brake device in which a pressure due to centrifugal force is generated in the working hydraulic chamber.
In the present invention, the orifice that connects the working hydraulic chamber and the centrifugal hydraulic chamber is not limited to the piston, and may be formed in, for example, a cylinder.

[0055]

According to the first aspect of the present invention, the pressure in the centrifugal hydraulic chamber is constantly maintained at the set pressure of the pressure regulating valve by the hydraulic pressure supply circuit, and the centrifugal force is controlled by some factor. Even if the pressure in the hydraulic chamber fluctuates from the set pressure, the function of returning the pressure to the set pressure is exhibited. Thus, the centrifugal fluid pressure chamber is maintained in a state in which the low pressure near the set pressure is constantly applied, and is always reliably filled with the working fluid such as oil.

That is, for example, when the hydraulic fluid in the hydraulic fluid chamber is drained to the drain side to release the fastening and the piston retreats and the volume of the centrifugal hydraulic chamber increases, the hydraulic pressure supply circuit is immediately turned on. The low pressure hydraulic fluid is supplied to the centrifugal hydraulic chamber by the action of the pressure regulating valve, and the pressure of the centrifugal hydraulic chamber is maintained near the set pressure, and the centrifugal hydraulic chamber is maintained in a state filled with the hydraulic fluid. . When the high-pressure hydraulic fluid is supplied to the hydraulic fluid chamber to start the fastening operation, and the piston moves forward to reduce the volume of the centrifugal hydraulic chamber, the action of the pressure regulating valve of the hydraulic pressure supply circuit is promptly performed. As a result, the hydraulic fluid in the centrifugal pressure chamber is drained to the drain side, and the pressure in the centrifugal pressure chamber is also maintained near the set pressure,
The centrifugal hydraulic chamber is maintained in a state of being filled with the hydraulic fluid.

Since the centrifugal fluid pressure chamber is always filled with the hydraulic fluid at the predetermined set pressure as described above, the fastening is released, that is, when the hydraulic fluid chamber is in communication with the drain side. However, the hydraulic fluid in the centrifugal hydraulic chamber is supplied to the hydraulic fluid chamber via the orifice, and as a result, the hydraulic fluid chamber is also constantly filled with the hydraulic fluid. At this time, a small amount of hydraulic fluid supplied from the centrifugal hydraulic chamber to the hydraulic fluid chamber via the orifice is supplied from the hydraulic pressure supply circuit by that amount, and the hydraulic fluid chamber is filled with the hydraulic fluid. And finally discharged from the hydraulic pressure chamber to the drain side. For this reason, even if air is mixed into the centrifugal hydraulic chamber or the working hydraulic pressure chamber in the non-fastened state, this air is actuated from the centrifugal hydraulic chamber to the drain side via the working hydraulic pressure chamber. As the liquid flows, the gas is finally exhausted to the drain side.

Therefore, according to the fastening device of the present invention,
The following excellent effects are achieved. (1) First, since the centrifugal fluid pressure chamber is always filled with the hydraulic fluid, the fastening force is generated by the centrifugal hydraulic pressure generated in the hydraulic fluid pressure chamber even when the fastening device is not fastened, thereby configuring the fastening device. It is possible to prevent a problem of causing the so-called drag of the fastening element to wear the fastening element without fail, which is much more reliable than before. This is because, in the conventional configuration in which the supply source of hydraulic fluid such as oil is simply communicated with the centrifugal pressure chamber and the hydraulic fluid is supplied to the centrifugal pressure chamber by centrifugal force, the engine is immediately started when the engine is started. Since the hydraulic fluid cannot be supplied and air is easily mixed in, the centrifugal hydraulic chamber cannot always be sufficiently filled with the hydraulic fluid.
Low pressure is positively applied, and the air mixed in the centrifugal pressure chamber is quickly exhausted through the orifice, ensuring that the centrifugal pressure chamber is always filled with hydraulic fluid. Thus, the centrifugal fluid pressure can be surely offset.

(2) Even when the fastening device is not operated, the hydraulic fluid chamber is filled with the hydraulic fluid, and the air mixed into the hydraulic fluid chamber is quickly exhausted by the flow passing through the orifice. Therefore, it is not necessary to pour the hydraulic fluid into the hydraulic fluid chamber at the start of the fastening operation and to bleed the air, and only the communication state of the hydraulic fluid chamber to the drain side is closed, and the hydraulic pressure of the hydraulic fluid chamber is reduced by the centrifugal fluid. The pressure immediately rises to the same level as the pressure chamber, and the responsiveness during operation of the fastening device is significantly improved. For this reason, there is an effect that the shifting operation of the automatic transmission becomes extremely smooth. When the piston advances at the start of the fastening operation, the hydraulic fluid in the centrifugal hydraulic chamber is quickly discharged by the action of the hydraulic pressure supply circuit as described above, so that the discharge of the hydraulic fluid is delayed. No deterioration in responsiveness occurs. (3) In addition, since a low pressure always acts on the centrifugal hydraulic chamber, and the force by this pressure also functions as a restoring force of the piston, the hydraulic fluid in the hydraulic hydraulic chamber is quickly discharged and the piston is quickly released when the fastening is released. Retreat to For this reason, also in this respect, there is an effect that the shift operation of the automatic transmission becomes extremely smooth.

Further, in the fastening device of the automatic transmission according to the second aspect, the orifice for communicating the working hydraulic pressure chamber and the centrifugal hydraulic pressure chamber is disposed on the inner diameter side of the piston. For this reason, the effect of exhausting the air mixed in the centrifugal fluid pressure chamber or the like is particularly remarkably exhibited, and the centrifugal fluid pressure can be more reliably and completely canceled out, and a more responsive fastening operation is realized. That is, in this case, the centrifugal force due to the idling of the piston etc. causes the working fluid with little mixed air to move to the outer circumference side, and the mixed air easily moves to the inner circumference side such as the centrifugal pressure chamber, so the mixed air Is quickly discharged by the flow of the hydraulic fluid through the orifice.

Further, in the fastening device for an automatic transmission according to the third aspect, the flow of oil from the working hydraulic chamber to the centrifugal hydraulic chamber 24 is cut off by the operation of the one-way hydraulic action mechanism. Oil does not leak from the hydraulic chamber to the centrifugal hydraulic chamber, the consumption of oil is reduced, and the discharge flow rate of an oil pump or the like can be saved. Further, the pressure in the working hydraulic chamber is increased more quickly, and the operation responsiveness can be further improved.

According to a fourth aspect of the present invention, in the automatic transmission fastening device, the one-way hydraulic pressure acting mechanism closes the tapered hole formed in the piston and the hydraulic fluid chamber by closing the tapered hole. And a ball that blocks the flow of the hydraulic fluid from the hydraulic fluid to the centrifugal pressure chamber, and a taper surface on the outer peripheral side of the piston in the tapered hole is parallel to the rotation axis of the fastening element. Sometimes, when the ball moves from the non-closed position to the closed position, it moves in the lateral direction and does not receive resistance due to centrifugal force. For this reason, the magnitude of the hydraulic pressure at which the ball moves to the closing position becomes constant irrespective of the rotation speed of the piston, the ball easily moves to the closing position regardless of the rotation speed, and the taper hole is closed more quickly. Will be. For this reason, the effect of saving the oil amount and the effect of improving the operation responsiveness described above become more remarkable.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a hydraulic pressure supply circuit for a centrifugal hydraulic chamber of a fastening device (high clutch H / C) in the automatic transmission.

FIG. 3 is a diagram showing a hydraulic pressure supply circuit for a working hydraulic pressure chamber of a fastening device (high clutch H / C) in the automatic transmission.

FIG. 4 is a diagram showing a skeleton of a transmission mechanism constituting the automatic transmission.

FIG. 5 is a diagram showing an operation state according to a shift position of each fastening device in the automatic transmission.

FIG. 6 is a sectional view of a main part of an automatic transmission according to a second embodiment of the present invention.

FIG. 7 is a sectional view of a main part of an automatic transmission according to a third embodiment of the present invention.

FIG. 8 is a view for explaining the operation and effect of the one-way hydraulic action mechanism in the automatic transmission.

FIG. 9 is a sectional view of a main part of an automatic transmission according to a fourth embodiment of the present invention.

[Explanation of symbols]

1a Center axis (rotating axis of fastening element) 11 Drum (driving element, cylinder) 12 Driven plate (fastening element) 13 Hub (driven element) 14 Drive plate (fastening element) 15 Piston 20 Working hydraulic chamber (working hydraulic pressure chamber) ) 23 Partition wall 24 Centrifugal hydraulic chamber (centrifugal hydraulic chamber) 25 Orifice 35 Piston (cylinder) 100 Hydraulic supply circuit (hydraulic supply circuit) 110 Pressure regulating valve 300, 400 One-way hydraulic action mechanism (one-way hydraulic action mechanism) 301 , 401 Tapered hole 302, 402 Ball 403 Tapered surface

Claims (4)

[Claims] 1. A fastening element which is actuated by being pressed by a hydraulically operated piston to connect a driving element and a driven element, a cylinder which slidably fits the piston, and A hydraulic fluid chamber formed on one side with the piston and the cylinder and supplied with a high hydraulic pressure for operating the piston in the fastening element pressing direction, and the piston and the piston on the other side of the piston. A centrifugal hydraulic chamber formed of a partition fixed to the cylinder and supplied with a low hydraulic pressure, and an orifice communicating the working hydraulic chamber and the centrifugal hydraulic chamber; And a hydraulic pressure supply circuit for applying a low hydraulic pressure via a pressure regulating valve to the automatic transmission. 2. The fastening device for an automatic transmission according to claim 1, wherein the orifice is disposed on an inner diameter side of the piston. 3. A fastening element that is operated by being pressed by a hydraulically operated piston and that can connect a driving element and a driven element; a cylinder that slidably fits the piston; A hydraulic fluid chamber formed on one side with the piston and the cylinder and supplied with a high hydraulic pressure for operating the piston in the fastening element pressing direction, and the piston and the piston on the other side of the piston. A centrifugal hydraulic chamber formed of a partition fixed to the cylinder and supplied with a low hydraulic pressure; and a hydraulic pressure supply circuit for applying a low hydraulic pressure to the centrifugal hydraulic chamber via a pressure regulating valve. Having a one-way hydraulic action mechanism that interrupts the flow of hydraulic fluid from the hydraulic hydraulic chamber to the centrifugal hydraulic chamber and passes hydraulic fluid from the centrifugal hydraulic chamber to the hydraulic hydraulic chamber. Features of automatic transmission Apparatus. 4. The one-way hydraulic action mechanism interrupts a flow of hydraulic fluid from the hydraulic fluid chamber to the centrifugal hydraulic chamber by closing the tapered hole formed in the piston and closing the tapered hole. The fastening device for an automatic transmission according to claim 3, wherein a tapered surface on an outer peripheral side of the piston in the tapered hole is parallel to a rotation axis of the fastening element.