JPH0117717Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a creep prevention device for a vehicle with an automatic transmission.

For vehicles equipped with an automatic transmission equipped with a torque converter, if the gear shift lever is set to the drive position (forward position) while the vehicle is stopped, the drag torque of the torque converter will cause the vehicle to move against the driver's will. This indicates a so-called creep phenomenon in which the vehicle tries to move forward. This creep force attempts to apply braking force to the idling engine, which is undesirable from a fuel economy perspective.When this happens, the transmission automatically puts the transmission into a neutral state and reduces power transmission between the engine and tires. cut off,
It is desirable to reduce the engine throttle valve accordingly to ensure economy.

Anti-creep devices constructed for such purposes are:
In preparation for a sudden start, when the throttle pedal is depressed from the idle position, it is required to return to the creep state as responsively as possible. For this reason, design considerations are taken to ensure that the response is not impaired; however, on the other hand, if you suddenly release your foot from the throttle pedal,
If the system's responsiveness is too good and it quickly returns to the anti-creep state, the engine mount rubber releases the stored elastic deformation energy all at once, resulting in an extremely unpleasant shock to the occupants.

Therefore, the applicant has previously proposed providing a certain period of time lag when detecting the idle state of the vehicle and activating the creep prevention device, but this method is not possible in systems that do not use solenoid valves. It was not used and an alternative was needed. In addition, it was previously proposed to install a damping throttle that is effective only against movement in one direction in the switching valve of the creep prevention device, but it is not possible to guarantee the above-mentioned time lag until high temperatures when the viscosity of the hydraulic oil decreases. The only option is to either make the opening of the throttle extremely small or to design the valve diameter to be sufficiently large, both of which will force sacrifices to other requirements such as mass production and compact design.

By the way, in order to ensure the operation of a creep prevention device, a plurality of valves are usually prepared, and the order of operation of these valves is determined. There are many chambers whose volumes change depending on the conditions, and the sum of the changes in the volumes of these chambers is quite large. Taking this into consideration, if the flow of the hydraulic oil that occurs due to the volume change is throttled, a sufficient damping effect can be obtained without the throttle opening being so small. Furthermore, by following the order of operation of each valve, the most important valve can be returned to the creep prevention device last, thereby creating a sufficient time lag.

The present invention was developed based on this point, and is an automatic transmission equipped with an extremely simple structure that creates a time lag when transitioning from a creep state to a creep prevention state, thereby preventing unpleasant shocks. The purpose of the present invention is to provide a creep prevention device for a vehicle.

To achieve this objective, the device of the invention comprises a hydraulic reservoir which is elastically inflatable and deflated and which is connected to the engine power detector; The spool valve body is movable in order to steplessly adjust the communication state between the communicating drain passages from fully open to fully closed, and the spool valve body faces one end of the spool valve body in order to act on the hydraulic pressure in the hydraulic storage chamber and bias it toward the closing side. and a second pilot hydraulic chamber provided facing the other end of the spool valve body so as to act on the operating pressure of the frictional engagement element and bias it toward the opening side. ; a one-way throttle that is disposed between the engine output detector and the hydraulic pressure storage chamber and generates throttle resistance only when the hydraulic pressure flows out from the hydraulic pressure storage chamber;

Hereinafter, the embodiments of the present invention will be explained with reference to the drawings. First, the present invention will be applied to four forward speeds and one reverse speed.
In FIG. 1, which shows an outline of an automatic transmission for a motor vehicle, the output of an engine E is transmitted from its crankshaft 1 through a hydraulic torque converter T as a fluid transmission device, an auxiliary transmission M, and a differential device Df in sequence. , and are transmitted to the drive wheels W, W' to drive them.

The torque converter T includes a pump impeller 2 connected to a crankshaft 1, a turbine impeller 3 connected to an input shaft 5 of an auxiliary transmission M, and a stator shaft 4a supported on the input shaft 5 so as to be relatively rotatable. It is composed of a stator wheel 4 connected via a one-way clutch 7. The torque transmitted from the crankshaft 1 to the pump impeller 2 is hydrodynamically transmitted to the turbine impeller 3, and during this time, when the torque is amplified,
As is known, the stator wheel 4 bears the reaction force.

A pump drive gear 8 for driving the hydraulic pump P shown in FIG. 2 is provided at the right end of the pump impeller 2, and a stator arm 4b for controlling the regulator valve Vr shown in FIG. 2 is fixed at the right end of the stator shaft 4a. will be established.

Mutually parallel input and output shafts 5 and 6 of the auxiliary transmission M
A first speed gear train G ₁ , a second speed gear train G ₂ , a third speed gear train G ₃ , a fourth speed gear train G ₄ , and a reverse gear train Gr are provided in parallel therebetween. The first gear train _G1 is
A drive gear 17 is connected to the input shaft 5 via a first speed clutch C ₁ , and an output shaft 6 is meshed with the gear 17 .
and a driven gear 18 which can be connected via a one-way clutch _C0 . The second speed gear train G ₂ consists of a driving gear 19 connectable to the input shaft 5 via a second speed clutch C ₂ and a driven gear 20 fixed to the output shaft 6 and meshing with the gear 19. 3rd gear train
G ₃ consists of a drive gear 21 fixed to the input shaft 5 and a driven gear 22 connected to the output shaft 6 via a third speed clutch C ₃ and meshable with the gear 21. In addition, the fourth speed gear train G ₄ is connected to the fourth speed clutch C ₄
a drive gear 23 connected to the input shaft 5 via;
The driven gear 24 is connected to the output shaft 6 via a switching clutch Cs and meshes with the gear 23 described above. Furthermore, the reverse gear train Gr includes a drive gear 25 that is integrally provided with the drive gear 23 of the fourth speed gear train _G4 .
, a driven gear 27 connected to the output shaft 6 via the switching clutch Cs, and an idle gear 26 meshing with both gears 25 and 27. The switching clutch Cs is provided between the driven gears 24, 27, and the driven gears 24, 27 can be changed by shifting the selector sleeve S of the clutch Cs to the forward position on the left or the reverse position on the right in the figure. It can be selectively connected to the output shaft 6. one way clutch
C ₀ transmits only the drive torque from engine E and no torque in the opposite direction.

Therefore, when the selector sleeve S is held in the forward position as shown in the figure, the first gear clutch is
If only C ₁ is connected, the drive gear 17 will be connected to the input shaft 5.
A first speed gear train G ₁ is established, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train G ₁ . Next, if the second speed clutch _C2 is connected while the first speed clutch _C1 is connected, the drive gear 19 is connected to the input shaft 5 and the second speed gear train is connected.
_G2 is established, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train _G2 . At this time, the first
The speed clutch _C1 is also engaged, but due to the action of the one-way clutch _C0 , the gear is not in first gear but in second gear, and this is the same for third and fourth gears. . When the second speed clutch _C2 is released and the third speed clutch _C3 is connected, the driven gear 22 is connected to the output shaft 6 to establish the third speed gear train _G3 , and the third speed clutch _C3 is connected. When the fourth speed clutch C4 is released and the fourth speed clutch _C4 is connected, the drive gear 23 is connected to the input shaft 5 and the fourth speed gear train _G4 is established. Furthermore, move the selector sleeve S of the switching clutch Cs to the right, and
If only speed clutch C ₄ is connected, drive gear 25
is connected to the input shaft 5, and the driven gear 27 is connected to the output shaft 6.
A reverse gear train Gr is established by being connected to the gear train Gr, and reverse torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train Gr.

The torque transmitted to the output shaft 6 is transmitted from the output gear 28 provided at the end of the output shaft 6 to the large diameter gear Dg of the differential device Df.

In FIG. 2, a hydraulic pump P sucks up oil from an oil tank R and pumps it into a hydraulic oil passage 29. After this pressure oil is regulated to a predetermined pressure by the regulator valve Vr, the manual valve Vm as a manual switching valve
sent to. This oil pressure is called line pressure Pl.

Excess pressure oil in regulator valve Vr is restricted to 3
3 into the torque converter T and pressurizes its interior to prevent cavitation.

The hydraulic oil passage 29 is connected to a throttle valve Vt and a governor valve Vg as engine output detectors.
Throttle valve Vt is a throttle pedal (not shown)
throttle pressure Pt is output to the pilot oil passage 48 as an index corresponding to the throttle opening of the engine E, that is, an index representing the output of the engine E. Also governor valve Vg
is the output shaft 6 of the auxiliary transmission M or the differential gear Df
is driven by a large-diameter gear Dg, etc., and applies oil pressure proportional to vehicle speed, that is, governor pressure Pg, to the pilot oil passage 49
Output to.

The manual valve Vm is interposed between an oil passage 39 branched from the hydraulic oil passage 29 and an oil passage 40, and has shift positions such as a neutral position, a drive position, and a reverse position, and when in the drive position, the oil passage 39 ，
Connect 40. Branched from oil path 40 and throttle 50
The oil passage ₄₁ with the
1st gear clutch when Vm is in drive position.
Hydraulic pressure can always be supplied to the hydraulic operating part of _C1 .
The oil pressure in the oil passage 40 is supplied to the first speed clutch C1, and is also supplied to the second speed clutch _C1 in accordance with the switching operations of the 1-2 shift valve _V1 , the 2-3 shift valve _V2 , and the 3-4 shift valve _V3 . It is selectively supplied to each hydraulic actuating section of the speed clutch C ₂ , third speed clutch C ₃ and fourth speed clutch C ₄ .

These shift valves V ₁ to _{V 3} have throttle pressure Pt and governor pressure Pg applied to both ends thereof.
As the vehicle speed increases, that is, the governor pressure Pg increases,
A switching operation is performed from the first switching position on the left side to the second switching position on the right side. In other words, the 1-2 shift valve V ₁ is
It is interposed between the oil passage 40 and an oil passage 42 having a throttle 43, and when the vehicle speed is low, both oil passages 4
It is in the first switching position that cuts off between 0 and 42. Therefore, in this state, only the first speed clutch _C1 is engaged, and the speed ratio of the first speed is established.

When the vehicle speed increases, the 1-2 shift valve _V1 is switched to the second switching position on the right side, and the oil passages 40 and 42 are communicated with each other. At this time, the 2-3 shift valve _V2 is in the first switching position shown, and the oil passage 42 is communicated with the oil passage 44 leading to the hydraulically actuated portion of the second speed clutch _C2 . Therefore, the first speed clutch C ₁ and the second speed clutch C ₂ are engaged, but due to the action of the one-way clutch C ₀ (see Figure 1), only the second speed gear train G _{2 is established and the second speed clutch C 2} is engaged. This is the speed ratio of 2nd speed.

When the vehicle speed further increases, the 2-3 shift valve _V2 switches to the second switching position on the right side, and the oil passage 42 is communicated with the oil passage 45. At this time, the 3-4 shift valve _V3 is in the first switching position on the left side as shown in the figure, and the oil passage 45 is communicated with an oil passage 46 leading to the hydraulic operating section of the third speed clutch _C3 . Therefore, the third gear clutch _C3 is engaged and the third gear speed ratio is established.

When the vehicle speed increases further, the 3-4 shift valve V ₃
is switched to the second switching position on the right side, and the oil passage 45 is
Oil passage 4 leading to the hydraulic operating part of the 4th speed clutch C ₄
7. Therefore, the fourth gear clutch C ₄
is engaged and the speed ratio of the fourth speed is established.

Now, a creep control circuit 51 is interposed in the middle of the oil passage 41 for supplying hydraulic pressure from the hydraulic pump P to the hydraulic operating part of the first speed clutch _C1 , which is a frictional engagement element for starting. This creep control circuit 51 includes a control valve 52 as a control means, a switching valve 53, a one-way throttle 54, and two one-way valves 5.
5, 56.

In the oil passage 41, a branch oil passage 57 is branched from between the throttle 50 and the hydraulically operated part of the first speed clutch _C1 , and a control oil passage 57 is branched between the branch oil passage 57 and a drain oil passage 58 leading to the oil tank R. A valve 52 is interposed.
The control valve 52 is a sliding valve, and includes a spool valve body 59 that is movable between a closed position on the right and an open position on the left, and a first pilot hydraulic chamber that faces the left end surface of the valve body 59. 60, a second pilot hydraulic chamber 61 facing the right end surface of the valve body 59, and a spring 62 housed in the first pilot hydraulic chamber 60 and biasing the valve body 59 toward the closing side. The pressure receiving area of the spool valve body 59 facing the first pilot hydraulic chamber 60 is the same as that of the second pilot hydraulic chamber 60.
It is set larger than the pressure receiving area facing the pilot hydraulic chamber 61. Furthermore, an annular groove 63 is provided on the outer periphery of the valve body 59 and is always in communication with the branch oil passage 57 .

Throttle pressure Pt is introduced into the first pilot hydraulic chamber 60 via an oil passage 64, and the first clutch is introduced into the second pilot hydraulic chamber 61 via an oil passage 65.
A working pressure of C ₁ can be introduced. Therefore, in the control valve 52, the valve body 59 is urged toward the closing side by the spring force of the spring 62 and the throttle pressure Pt of the first pilot hydraulic chamber 60, and the first speed clutch in the second pilot hydraulic chamber 61 is biased. The valve body 59 is biased toward the opening side by the operating pressure of C ₁ , and the throttle pressure
In the idle position, where Pt is zero, the operating pressure of the first gear clutch C ₁ is maintained at a predetermined pressure P ₀ determined by the spring 62. By setting this predetermined pressure P ₀ to be approximately equal to or lower than the spring force of a return spring (not shown) in the hydraulic actuation part of the first gear clutch C ₁ , the operating pressure is maintained at the predetermined pressure P ₀ . By doing so,
The first gear clutch C ₁ is not substantially engaged and creep is prevented.

The switching valve 53 connects an oil passage 66 further branched from the branch oil passage 57 and a drain oil passage 67 leading to the oil tank R.
and a second pilot hydraulic chamber 61 of the control valve 52.
This is a sliding valve interposed between the oil passage 65 and the oil passage 65 leading to the oil passage 65. The switching valve 53 includes a spool valve element 68 that moves between a first switching position on the right and a second switching position on the left, and a spring 69 that biases the spool valve element 68 toward the second switching position. and a hydraulic pressure storage chamber 70 facing the left end surface of the spool valve body 68. Further, the right end surface of the plunger 71 can come into contact with the left end surface of the spool valve body 68, and the hydraulic chamber 72, which the left end surface of the plunger 71 faces, is connected to an oil passage 47 that supplies operating hydraulic pressure to the fourth speed clutch _C4 . The hydraulic pressure for the fourth gear clutch _C4 is introduced. Moreover, in the hydraulic storage chamber 70,
Throttle pressure Pt is introduced via oil passage 73.

In this switching valve 53, when the spring force of the spring 69 overcomes the throttle pressure Pt of the oil pressure storage chamber 70 and the spool valve body 68 is at the second switching position as shown in the figure, the oil passages 66 and 65 are closed. When the oil drain passage 67 is communicated with the oil passage 67 and is isolated from the oil passage 65, and when the throttle pressure Pt of the oil pressure storage chamber 70 overcomes the spring force of the spring 69 and the spool valve body 68 is in the first switching position, the oil passage 66, 65 is isolated, and the oil drain path 6
7 is communicated with the oil passage 65.

Here, the spring 62 of the control valve 52 and the switching valve 53
The spring force of the spring 69 is set as follows. That is, as the throttle pressure Pt gradually increases from the idle position, the control valve 5 first
The spool valve body 59 of No. 2 moves toward the closed position shown in the figure, and the operating pressure of the first speed clutch C ₁ reaches the predetermined value P ₁
After increasing the pressure to
8 moves to the right side to the first switching position, and the oil passage 65
is communicated with the oil drain path 67.

First pilot hydraulic chamber 60 of the control valve 52
Throttle pressure is applied to the hydraulic storage chamber 70 of the switching valve 53.
In order to act on Pt, the oil passage 73 is branched from the pilot oil passage 48 of the throttle valve Vt, and one-way valves are installed in the middle of this oil passage 73 in order from the throttle valve Vt toward the switching valve 53 side. 55 and
A one-way diaphragm 54 is provided. One way valve 55
is provided so as to only allow the throttle pressure Pt to flow from the throttle valve Vt toward the switching valve 53. Further, the one-way throttle 54 is a throttle valve.
One-way valve 7 provided to only allow throttle pressure Pt to flow from Vt toward switching valve 53
4 and a throttle 75 connected in parallel to the one-way valve 74, which provides greater resistance when the throttle pressure Pt flows out of the hydraulic pressure storage chamber 70 than when it flows into the hydraulic storage chamber 70.
The one-way throttle 54 of this oil passage 73 and the hydraulic storage chamber 7
0, an oil passage 64 communicating with the first pilot hydraulic chamber 60 in the control valve 52 is branched.

The one-way valve 56 is the one-way valve 5 in the oil passage 73.
5 and the one-way throttle 54, and the control valve 5
The one-way valve 56 and the annular groove 63 are provided in the middle of the oil passage 76 that communicates with the annular groove 63 in the annular groove 63. A throttle 77 is provided in the middle of the oil passage 76 between the two. Furthermore, an oil passage 78 is branched from between the one-way valve 55 and the one-way throttle 54 in the oil passage 73, and this oil passage 78 is a two-port two-position switching valve that is switched in conjunction with the manual valve Vm. It is connected to the pilot oil passage 48 via 79. In the case of a system having a forward shift lever position without a creep prevention function, the 2-port 2-position switching valve 79 switches from the illustrated communicating position to the isolated position in conjunction with the manual valve Vm, and accordingly switches to the first gear. The operating pressure of clutch C ₁ acts via one-way valve 56 on first pilot hydraulic chamber 60 of control valve 52 . As a result, the operating pressure of the first speed clutch _C1 acts equally on both left end surfaces of the spool valve body 59 of the control valve 52, and the spool valve body 59
Since the left side pressure receiving area of 9 is larger than the right side pressure receiving area, the spool valve body 59 is shifted to the closed position.

Next, the operation of this embodiment will be explained with reference to FIG. 3. When the throttle pressure Pt increases from the idle position and the operating pressure of the first speed clutch _C1 reaches the predetermined pressure _P1 , the switching valve 53 Since the control valve 52 is switched to the first switching position and the oil passage 65 is communicated with the oil drain passage 67, the oil pressure in the second pilot oil pressure chamber 61 becomes zero for the control valve 52. Therefore, the valve body 59 of the control valve 52 suddenly moves to the closed position,
After this, the operating pressure becomes equal to the line pressure Pl. When the throttle pedal is returned to the idle position from this state, the switching valve 53 first returns to the second switching position shown, and then the spool valve body 59 of the control valve 52
is pushed back to the open position. As a result, the state returns to the creep prevention state, but at this time, the hydraulic pressure in the hydraulic storage chamber 70 is throttled by the throttle 75 and flows out, so that the switching valve 52 returns to the second switching position. is delayed and thus the rate of transition to the anti-creep state is slowed. However, the aperture 75 is
Due to the action of the one-way valve 74 parallel to this, it is effective only when returning to the creep prevention state, and does not exhibit its throttling function when transitioning to the creep state, such as during a sudden start. Moreover, the pressure oil flow rate throttled by the throttle 75 corresponds to the displacement volume caused by the contraction of the pressure oil storage chamber 70 and the first pilot hydraulic chamber 60 of the control valve 52, that is, by the movement of each spool valve body 59, 68 to the left. The flow rate is only 1
The flow rate is larger than that in the case of displacement by one valve, and therefore there is no need to make the diameter of the throttle 75 extremely small.

Further, unless the switching valve 53 returns to the illustrated second switching position, the spool valve body 5 of the control valve 52
Spring 69, 6 prevents 9 from moving to the open position.
Since the spring force of 2 is set, delaying the return of the switching valve 53 to the second switching position using the throttle 75 is very effective in gaining time delay. In this sense, if necessary, a restriction 80 may be further provided in the middle of the oil passage 73 from the connection position with the oil passage 64 to the oil pressure storage chamber 70.

While running at high speed in the fourth gear, the operating pressure of the fourth gear clutch C ₄ acts on the hydraulic chamber 72 to press the plunger 71 , which projects into the hydraulic reservoir chamber 70 and contacts the spool valve body 68 . Because of this contact, the spool valve body 68 does not move to the first switching position, and therefore the creep prevention state does not occur.

In the above embodiment _, creep is prevented by draining the operating pressure of the first speed clutch _C1 into the oil tank R.
The present invention can also be applied to a system in which the upper limit of the operating pressure of the engine is regulated to a pressure proportional to the throttle pressure Pt, and FIG. 4 shows an example of this.

In FIG. 4, the creep control circuit 51' connects the oil passage 41, the oil drain passage 58, and the first speed clutch C1 _.
A control valve 52' is interposed between the control valve 52' and the control valve 52' to regulate the upper limit of the operating pressure of the first speed clutch _C1 to a value proportional to the throttle pressure Pt.

As is clear from the above explanation, the hydraulic storage chamber 7
0 is when you suddenly take your foot off the throttle pedal.
It functions as an accumulator, and after the throttle pressure becomes zero, it functions as a supply source of hydraulic pressure that temporarily acts on the first pilot hydraulic chamber 60 of the control valve 52. Therefore, the present invention can be interpreted to include a structure in which a small-capacity accumulator is arranged in parallel with the control valve 52 instead of the switching valve 53.

Further, in the above embodiment, a hydraulic first speed clutch is exemplified as the starting frictional engagement element, but a brake band often used in planetary gears or the like may also be used.

As described above, the device of the present invention includes a hydraulic storage chamber that is elastically expandable and contractible and connected to an engine output detector; an oil passage leading to the starting frictional engagement element and an oil drain passage leading to the oil tank. A movable spool valve body to steplessly adjust the communication state between the two from fully open to fully closed; a control valve comprising a first pilot hydraulic chamber and a second pilot hydraulic chamber provided facing the other end of the spool valve body so as to apply the operating pressure of the frictional engagement element to bias it toward the opening side; and engine output detection. This includes a one-way throttle that is placed between the engine output detector and the oil pressure storage chamber, and that produces throttling resistance only when oil pressure flows out from the oil pressure storage chamber. When the control valve is closed to enter the creep state and the throttle pedal is returned to the idle state,
The one-way throttle valve gradually decreases the hydraulic pressure accumulated in the fluid pressure storage chamber and gradually reduces the hydraulic pressure in the first pilot hydraulic chamber of the control valve. It is possible to delay the return operation and create a time lag when transitioning from the creep state to the creep prevention state. This can prevent unpleasant shots from being transmitted to the occupants.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an automatic transmission for automobiles with four forward speeds and one reverse speed to which the device of the present invention is applied, Fig. 2 is a hydraulic control circuit diagram of an embodiment of the present invention, and Fig. 3 is a creep control circuit. FIG. 4 is a hydraulic control circuit diagram of another embodiment of the present invention. 52, 52'...Control valve, 53...Switching valve, 5
4... One-way throttle, 58... Oil drain path, 59, 68
... Spool valve body, 60 ... First pilot hydraulic chamber, 61 ... Second pilot hydraulic chamber, 65, 66
...Oil passage, 70...Hydraulic storage chamber, _C1 ...First speed clutch as a starting friction engagement element, M...Auxiliary transmission, P...Hydraulic pump as a hydraulic source, R
...Oil tank, T...hydraulic torque converter as a fluid transmission device, Vt...throttle valve as an engine output detector.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A fluid transmission device T; connected to the fluid transmission device T by having a hydraulically actuated starting friction engagement element _C1 that increases the transmission capacity in accordance with an increase in the introduced hydraulic pressure. an auxiliary transmission M; a hydraulic pressure source P for supplying hydraulic oil to the frictional engagement element _C1 ; and an engine output detector Vt that outputs hydraulic pressure representative of the engine output. In the vehicle,
A hydraulic reservoir chamber 70 that is elastically expandable and contractible and connected to the engine output detector Vt; an oil passage 66 leading to the starting frictional engagement element C ₁ and an oil drain passage 58 leading to the oil tank R; A movable spool valve body 59 is provided to steplessly adjust the communication state from fully open to fully closed, and a movable spool valve body 59 is provided facing one end of the spool valve body 59 to bias it toward the closing side by applying hydraulic pressure from a hydraulic reservoir chamber 70. the first pilot hydraulic chamber 60 and the frictional engagement element C ₁
between the control valve 52, which includes a second pilot hydraulic chamber 61 facing the other end of the spool valve body 59, and the engine output detector Vt and the hydraulic reservoir chamber 70, so as to bias it toward the opening side by applying the operating pressure of the control valve 52; A creep prevention device for a vehicle with an automatic transmission, comprising: a one-way throttle 54 which is disposed in a hydraulic pressure storage chamber 70 and generates throttle resistance only when hydraulic pressure flows out from a hydraulic pressure storage chamber 70; (2) The hydraulic pressure storage chamber 70 is a starting friction engagement element.
The switching valve 53 is provided facing one end of the spool valve body 68 in the sliding type switching valve 53 that switches between communication and isolation between the oil passage 66 leading to C ₁ and the oil passage 65 leading to the second pilot hydraulic chamber 61.
creep of a vehicle with an automatic transmission according to claim (1) of the utility model registration, characterized in that the vehicle is configured to be in a cut-off state when the output oil pressure of the engine output detector Vt is equal to or higher than a predetermined value. Prevention device.