JP3604887B2 - Hydraulic control device for automatic transmission - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydraulic control device for an automatic transmission that can control a hydraulic pressure applied to a fastening element such as a clutch without delaying a response.
[0002]
[Prior art]
As is well known, in an automatic transmission, a coupling element (clutch or brake) is in a state similar to a half-clutch that absorbs a rotation difference between an input shaft and an output shaft during gear shifting, and is supplied to and discharged from the coupling element. If the oil pressure is not properly controlled, a large shift shock will occur.
Therefore, conventionally, a hydraulic element called an accumulator is used to maintain the hydraulic pressure applied to the fastening element at a constant pressure (shelf pressure) only during shifting, so that the clutch capacity required so that the fastening element does not slip upon completion of shifting. That is, the so-called shelf pressure control is performed to increase the hydraulic pressure up to this point.
[0003]
In recent years, instead of such shelf pressure control by an accumulator, a system has been devised in which the hydraulic pressure supplied to and discharged from the fastening element is directly duty controlled by a solenoid.
In this type of system, the pressure is regulated by an amplification valve that generates a hydraulic pressure according to the solenoid drive current. When using the amplification valve, hydraulic pressure applied to the fastening element as shown by a dotted line in FIG. 15 (b), the piston stroke time points t ₂ after completion of the fastening element, oil flow stops abruptly As a result, the line pressure continues to be directly applied to the clutch until the amplification valve shifts from a state where there is an oil flow to a state where there is no oil flow, so that the oil pressure rises to a target value or more. As a result, the hydraulic pressure overshoots, whereby a pressure equal to or higher than the target pressure is applied to the fastening element, and as a result, the transmission torque to the output shaft fluctuates, causing a shift shock.
[0004]
Therefore, conventionally, in such a hydraulic control device using the pressure adjusting method, as shown in FIG. 14, in order to avoid the above-described overshoot, a pressure adjusting section 2 including a solenoid 2a and an amplification valve 2b and a fastening element 1 And an orifice 4 for generating a flow rate according to the pressure difference, and an accumulator 6 is connected to the oil passage 3 between the orifice 4 and the fastening element 1 via an oil passage 5 for a shock absorber. It has a configuration.
[0005]
According to such a configuration, when the piston of the fastening element 1 has completed the stroke (see FIG. 15A), the oil pressure in the oil passage 5 for the shock absorber increases, and this pressure is higher than the urging force of the spring SP in the accumulator 6. If it wins, the piston PT of the accumulator 6 starts to stroke, and the oil pressure in the oil passage 5 for the buffer decreases. As a result, the oil flow does not stop suddenly due to the oil flow generated in the orifice 4, the rise of the oil pressure becomes gentle, and the above-described overshoot of the oil pressure (see FIG. 15B) is avoided.
That is, the accumulator 6 acts as a damper that absorbs hydraulic overshoot. The configuration in which the accumulator 6 acts as a damper is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-207602.
[0006]
[Problems to be solved by the invention]
By the way, in the conventional hydraulic control device described above, the accumulator 6 is provided to dampen the overshoot of the hydraulic pressure applied to the fastening element 1. However, the provision of the accumulator 6 has the following adverse effects.
[0007]
(1) At the time of shifting, it is necessary to precisely and directly control the hydraulic pressure to be applied to the fastening element 1 in real time, but at this time, the oil stored in the accumulator 6 also changes, so that compared to the case without the accumulator 6 Therefore, there is a problem that a longer time is required until the target pressure is reached as shown in FIG.
[0008]
{Circle around (2)} After the shift is completed, it is necessary to set the oil pressure to a high pressure so that the fastening element 1 does not slip. In this case, too, the flow rate is applied to the accumulator 6 and the area shown in FIG. As indicated by E2, there is also a problem that the hydraulic pressure cannot be rapidly raised, resulting in a slow rising characteristic.
[0009]
In other words, in other words, in the conventional hydraulic control device, the overshoot of the hydraulic pressure can be damped by the accumulator 6, but the damping characteristic of the accumulator 6 causes a response delay in the hydraulic control related to the shift. However, there is a problem that fine control cannot be performed.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydraulic control apparatus for an automatic transmission that does not cause a response delay while suppressing hydraulic pressure overshoot.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, an oil path for a shock absorber branched and connected to a first oil path that supplies and discharges oil pressure to and from a fastening element, and an accumulator connected to the oil path for the shock absorber In the hydraulic control device having the hydraulic pressure control device having a predetermined hydraulic pressure is applied from the state where no hydraulic pressure is applied to the fastening element until the first set time elapses, to open the oil passage for the shock absorber to enable the damper action of the accumulator, After the first set time has elapsed, a damper control means for shutting off the oil passage for the shock absorber and disabling a damper function of the accumulator is provided.
[0012]
Further, in the invention according to claim 2 that is dependent on the first aspect, a preferred embodiment, the damper control unit, for blocking and opening the shock absorber oil passage is branched and connected to the first oil path valve And a second oil passage branched and connected to the first oil passage and having an orifice formed therein to apply an operating pressure corresponding to the oil pressure of the first oil passage to the valve. I do.
Further, according to the third aspect of the present invention, the damper control means electromagnetically drives the actuator in accordance with the oil pressure of the first oil passage, and controls the accumulator connected to the shock absorber oil passage. It is characterized by being directly fixed and released.
[0013]
According to the fourth aspect of the present invention, the hydraulic control device includes an accumulator that communicates with the first oil passage that supplies and discharges hydraulic pressure to and from the fastening element, and absorbs an overshoot of hydraulic pressure that occurs after the piston stroke of the fastening element. In the above, the first set time elapses after the stroke of the piston of the fastening element is completed from a state in which no hydraulic pressure is applied to the fastening element, which is disposed in a buffer oil passage that communicates the first oil path and the accumulator. Until the opening of the damper function of the accumulator by opening the oil path for the shock absorber and disabling the damper function of the accumulator by closing the oil path for the buffer after the first set time has elapsed, When a second set time has elapsed after completion of the stroke of the piston of the fastening element, the valve stores the valve in the accumulator. Characterized in that a discharge means for discharging the oil.
Further, according to the invention described in claim 5 dependent on claim 4 , the first set time is set longer than the second set time.
[0014]
In the present invention, the oil passage for the shock absorber is opened until the first set time elapses from the state in which no oil pressure is applied to the fastening element until the predetermined oil pressure is applied, and the damper action of the accumulator is made effective. After the lapse of time, the oil passage for the shock absorber is shut off to invalidate the damper function of the accumulator, so that it is possible to control the hydraulic pressure without delaying the response while suppressing the overshoot of the hydraulic pressure.
Therefore, when shifting, the damper function is invalidated when the hydraulic pressure applied to the fastening element becomes higher than the target pressure, so that the fluctuation of the oil amount caused by the change of the oil amount stored in the accumulator is eliminated as in the conventional case. Therefore, the hydraulic pressure applied to the fastening element can be increased to the target pressure in a short time.
After the shift is completed, the hydraulic pressure is increased so that the fastening element does not slip. In this case, too, the damper function is invalidated, so that the hydraulic pressure can be rapidly increased without delay in response as in the related art. .
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an example of a hydraulic control device according to an embodiment of the present invention will be described with reference to the drawings.
A. First Embodiment (1) Structure FIG. 1 is a diagram showing a schematic structure of a hydraulic control device according to a first embodiment of the present invention. In this figure, the same parts as those of the conventional example shown in FIG. 14 are denoted by the same reference numerals, and description thereof will be omitted.
The hydraulic control device shown in FIG. 1 is different from the conventional example shown in FIG. 14 in that a cut valve 12 that opens and shuts off a shock absorber oil passage 5 that connects an oil passage 3 and an accumulator 6 is provided. And an oil passage 10 having an orifice 11 formed therein so as to apply an operating pressure corresponding to the oil pressure of the oil passage 3. The cut valve 12 is operated under the conditions described later to shut off the shock absorber oil passage 5. That is, the damper function of the accumulator 6 is invalidated. Hereinafter, such a structure will be described.
[0016]
The cut valve 12 is composed of a spool 12a facing the oil passage 10 and a spring 12b for urging the spool 12a toward the oil passage 10, and the force by the oil pressure in the oil passage 10 is applied to the spring 12b. When the force becomes higher than the power, the spool 12a strokes in response to the stroke, and shuts off the buffer oil passage 5 communicating with the accumulator 6.
That is, when the oil is not supplied to the fastening element 1 and the oil pressure is not applied to the oil passage 3, the cut valve 12 causes the spool 12a to move the spool 12a by the spring 12b as shown on the right side of the center line CL in FIG. It is urged toward the road 10 to open the shock absorber oil passage 5 connected to the accumulator 6.
[0017]
On the other hand, when the hydraulic pressure of the fastening element 1 rises and a hydraulic pressure greater than the hydraulic pressure that balances the load of the spring 12b acts on the oil passage 10, the cut valve 12 moves the spool 12a as shown on the left side of the center line CL in FIG. A stroke is made toward the shock absorber oil passage 5 to shut off the shock absorber oil passage 5 connected to the accumulator 6.
The load of the spring 12b is set to a value such that the spool 12a moves upward in FIG. 1 by a hydraulic pressure slightly higher than a hydraulic pressure necessary for the piston 1a of the fastening element 1 to stroke against the return spring 1b. ing. The orifice 11 provided in the oil passage 10 sufficiently guarantees that the stroke time (movement time) of the spool 12a rises from the hydraulic pressure at the end of the piston stroke to the target hydraulic pressure in the fastening element in FIG. The diameter is set so as to be as short as possible within the range obtained.
Thus, the cut valve 12 that shuts off the oil passage 5 for the shock absorber does not stroke the spool 12a while oil is supplied to the fastening element 1, starts to stroke after the piston stroke of the fastening element 1 ends, and after a predetermined time has elapsed. Has the property of completing the stroke.
[0018]
(2) Operation Next, the operation of the hydraulic control device having the above structure will be described with reference to FIG. Now, for example, it is assumed that an AT control unit (not shown) supplies a solenoid drive signal to the pressure adjusting unit 2 (see FIG. 14) at the time of shifting. Then, the pressure regulating unit 2 starts supplying oil to the oil passage 3 through the orifice 4 to apply the target pressure to the fastening element 1 (time t1), and the piston of the fastening element 1 is accordingly moved to the state shown in FIG. So, start to stroke.
[0019]
On the other hand, at this time, the return spring equivalent pressure supplied to the oil passage 3 is also applied to the oil passage 10, but the pressure does not reach the stroke start pressure of the spool 12a exceeding the urging force of the spring 12b. The state of contact with the oil passage 10 is maintained. That is, the cut valve 12 opens the shock absorber oil passage 5 and sets the accumulator 6 to the operating state.
[0020]
Next, at the time point t2, the piston of the fastening element 1 has completely stroked, and the flow of the oil stops suddenly. Then, the oil pressure in the oil passage 3 and the oil passage 5 for the shock absorber tends to rise rapidly. At this time, since the oil passage 5 for the shock absorber is open, the accumulator piston PT strokes and the oil This causes a flow, suppresses a rapid rise in oil pressure in the oil passage 3, and acts as a damper that suppresses the above-described overshoot.
[0021]
While the accumulator 6 acts as a damper, the oil pressure in the oil passage 10 increases together with the oil pressure applied to the fastening element 1, and at a time t3 when the pressure exceeds the stroke start pressure (see FIG. 2B). The spool 12a starts to stroke as shown in FIG.
[0022]
The stroke of the spool 12a is completed at a time point t5 (first set time) when a certain time has elapsed from the time point t4 when the hydraulic pressure applied to the fastening element 1 reaches the target pressure, and the oil passage 5 for the shock absorber is shut off. As a result, the cut valve 12 sets the accumulator 6 to the inoperative state, and invalidates the damper function.
[0023]
As described above, according to the first embodiment, the hydraulic pressure is applied to the fastening element 1 from a state in which the hydraulic pressure is not applied to the fastening element 1, and the first set time after the stroke of the piston of the fastening element 1 ends. Until the passage, the damper function of the accumulator 6 is made effective by opening the oil path 5 for the shock absorber, and the cut valve 12 that shuts off the oil path 5 for the shock absorber and disables the damper action of the accumulator 6 after the first set time has elapsed. With this arrangement, hydraulic control without response delay while suppressing overshoot of hydraulic pressure is realized.
[0024]
That is, at the time of shifting, the damper function of the accumulator 6 is invalidated after the lapse of the first set time from the end of the stroke of the piston of the fastening element 1, so that the change in the amount of oil stored in the accumulator 6 differs from the conventional case. Therefore, when it is desired to finely control the hydraulic pressure applied to the fastening element 1, the response to the target hydraulic pressure can be increased.
After the shift is completed, the operating pressure is increased to set the operating pressure to a high pressure so that the fastening element 1 does not slip. In this case as well, since the damper function of the accumulator 6 is disabled, as in the related art, It is possible to rapidly increase the hydraulic pressure without delaying the response.
[0025]
In the above-described first embodiment, at a time point t5 when a predetermined time has elapsed from the time point t4 when the hydraulic pressure applied to the fastening element 1 reaches the target pressure, the oil passage 5 for the shock absorber is shut off and the damper action of the accumulator 6 is performed. However, the time width from the time point t4 to the time point t5 can be arbitrarily set according to the shape of the orifice 11, and the hydraulic pressure applied to the fastening element 1 reaches the target pressure after the end of the piston stroke. May be set to an optimum time width within which the stroke of the spool 12a is completely completed within a range in which the stroke can be sufficiently guaranteed and in a time as short as possible.
[0026]
Further, in this embodiment, the oil passage 10 and the orifice 11 are provided to apply the operating pressure to the cut valve 12, but instead, the cut valve 12 is electromagnetically controlled using a known solenoid valve. May be. Specifically, the opening and closing timing of the valve may be a predetermined time after the shift signal is given as shown in FIG. 10, or a pressure switch may be provided in the oil passage 3 as shown in FIG. An example in which a predetermined time has elapsed after the switch is turned on may be considered. In this case, the predetermined time may be changed depending on the temperature or the like. In this case, the structure is simplified, the valve opening / closing timing is easily controlled, and the responsiveness can be further improved.
[0027]
Further, in the above-described first embodiment, the damper function of the accumulator 6 is disabled or enabled by shutting off and opening the oil passage 5 for the shock absorber by the cut valve 12, but instead, for example, a normal accumulator structure is used. In addition, as shown in FIG. 12, an actuator 20 for directly electromagnetically locking the piston of the accumulator is provided, and when absorbing an overshoot of hydraulic pressure, a damper function is performed in the same manner as described above, and this is invalidated. When desired, the piston stroke can be locked by the pin 21 of the actuator 20 to nullify the damper action.
[0028]
B. Second Embodiment In the above-described first embodiment, the hydraulic pressure is applied to the fastening element 1 from a state in which no hydraulic pressure is applied to the fastening element 1, and the first set time elapses after the piston stroke ends. A cut valve 12 is provided to open the oil path 5 for the shock absorber to make the damper function of the accumulator 6 effective, and to cut off the oil path 5 for the shock absorber after the elapse of the first set time to invalidate the damper function of the accumulator 6. In this structure, when the hydraulic pressure of the fastening element 1 is released, the oil stored in the accumulator 6 also needs to be discharged.
[0029]
For this reason, even if it is attempted to reduce the oil pressure so as to cause a change in the capacity of the accumulator 6 beyond the oil discharge capacity of the hydraulic circuit shown in FIG. 1 or the pressure adjusting system (not shown), as shown in FIG. There is a problem that the oil pressure does not drop to the target oil pressure until the oil discharge of No. 6 is completed.
[0030]
That is, the above-mentioned adverse effects will be described in detail with reference to FIGS. 1 and 4. In the cut valve 12, the hydraulic pressure is released to release the fastened fastening element 1, and the oil passage 3 communicating with the fastening element 1 is released. When the pressure drops and the oil pressure in the oil passage 10 acting on the cut valve 12 falls below the spool stroke start pressure (time t8 in FIG. 4), the oil passage 3 for the shock absorber and the oil passage 3 leading to the accumulator 6 are shut off. The spool 12a of the cut valve 12 is stroked in the downward direction in the drawing, and the closed accumulator 6 communicates with the oil passage 3 again (time t9 in FIG. 4).
[0031]
As a result, since the oil stored in the accumulator 6 returns to the oil passage 3, an extra oil discharge is required as compared with the case where the accumulator 6 is not provided. When the piston No. 1 is in the middle of the stroke toward the release side, the oil stored in the accumulator 6 is transferred to the fastening element circuit in spite of the oil removal process as shown in the time t3 to t4 in FIG. It can be a factor that causes the adverse effect that the backflow occurs and the fastening element 1 is fastened again.
[0032]
Therefore, in the second embodiment, a mode of preventing the oil backflow phenomenon from the accumulator 6 when the fastening element 1 is released while avoiding the response delay while suppressing the hydraulic overshoot will be described.
The difference between the hydraulic control device according to the second embodiment and the first embodiment is that when the above-described spool 12a (see FIG. 1) is fully stroked upward in the drawing, it is stored in the accumulator 6 via the oil passage 5. The drain circuit D for discharging the oil is provided in the cut valve 12.
Hereinafter, such points will be described with reference to FIGS. In the hydraulic control device according to the second embodiment shown in FIGS. 5 to 7, the same reference numerals are given to the parts common to the first embodiment shown in FIG.
[0033]
First, in state A shown in FIG. 5, that is, in a state before the oil pressure is supplied to the oil passage 3 (prior to t1 in FIG. 8), the spool 12a of the cut valve 12 is urged downward by a spring 12b. ing.
While oil is supplied to the oil passage 3 to fasten the fastening element 1 and the piston of the fastening element 1 is stroked (time t1 to t2 in FIG. 8), the oil passage 10 is equivalent to the return spring of the fastening element 1. Only pressure is applied. With this hydraulic pressure, the biasing force of the spring 12b is set so that the spool 12a does not stroke. In this state, the spool 12a is maintained at the position shown in FIG.
[0034]
Then, when the piston stroke of the fastening element 1 ends (time t2 in FIG. 8), the oil pressure in the oil passage 3 starts to increase, and the oil pressure in the oil passage 10 also increases accordingly. When the oil pressure in the oil passage 10 exceeds the spool stroke start pressure, the spool 12a of the cut valve 12 starts to start a stroke (time t3 in FIG. 8), and the spool 12a moves according to the flow velocity determined by the orifice 11, and the oil passage In the shortest time within a range that can sufficiently guarantee that the oil pressure of No. 3 reaches the target pressure immediately after the end of the piston stroke (time t4 in FIG. 8), the hydraulic control device operates in the state B shown in FIG. t5 (first set time)). In this state B, the oil passage 5 for the shock absorber communicating with the accumulator 6 is cut off from the oil passage 3, so that the delay of the hydraulic pressure by the accumulator 6 thereafter can be avoided as in the first embodiment.
[0035]
Thereafter, when the spool 12a of the cut valve 12 further strokes to reach the state C shown in FIG. 7 (time t6 (second set time) in FIG. 8), the buffer oil passage 5 communicates with the drain circuit D. . Then, the oil stored in the accumulator 6 to absorb the overshoot is discharged from the drain circuit D (time t6 to t7 in FIG. 8), whereby no oil remains in the accumulator 6. This prevents oil backflow from the accumulator 6 when the fastening element 1 is released.
Needless to say, the stroke and diameter of the spool 12a, the diameter of the orifice 11, and the like are set so that the drain of the oil remaining in the accumulator 6 is sufficiently completed by the end of the shift.
[0036]
In the second embodiment described above, the spool 12a of the cut valve 12 shuts off the oil passage 5 for the buffer, and then the oil stored in the accumulator 6 is discharged. The invention is not limited to this, and a so-called underlap structure may be used in which the oil stored in the accumulator 6 is discharged before the spool 12a of the cut valve 12a completely shuts off the oil passage 5 for the shock absorber.
With the underlap structure, when the fastening element 1 is released, the state shown in FIG. 9 is instantaneously obtained, and the oil passage 3 is in a state of being connected to the drain circuit D, and is accumulated in the fastening element 1 via the cut valve 12. The oil that is drained will be released quickly. In this way, after the shift is completed, a new gear stage is established, so that the oil backflow phenomenon from the accumulator 6 when the engaged fastening element 1 is released again can be prevented.
[0037]
According to the first aspect of the present invention, the first oil passage for supplying / discharging the hydraulic pressure to / from the fastening element is configured to include a shock absorber oil passage branched and connected to the first oil passage, and an accumulator connected to the shock absorber oil passage. The damper control means opens the oil path for the shock absorber until a predetermined oil pressure is applied from a state where no oil pressure is applied to the fastening element and a first set time elapses, thereby enabling the damper action of the accumulator, and After the elapse of one set time, the oil passage for the shock absorber is shut off to invalidate the damper function of the accumulator, so that the hydraulic pressure can be controlled without causing a response delay while suppressing the hydraulic overshoot. Therefore, at the time of shifting, since the hydraulic pressure applied to the fastening element can converge to the target pressure in a short time, the hydraulic pressure can be rapidly increased without delay in response after the shift is completed, and the wood grain having excellent responsiveness can be obtained. Fine hydraulic control can be realized.
According to the second aspect of the present invention, the damper control means includes a valve for shutting off / opening the shock absorber oil passage branched and connected to the first oil passage, and a branch connection to the first oil passage. And a second oil passage having an orifice formed therein to apply an operating pressure corresponding to the oil pressure of the first oil passage to the valve. Therefore, after the shift is completed, the oil pressure is rapidly increased without delay in response. Pressure can be increased, enabling fine hydraulic control with excellent responsiveness.
According to the third aspect of the present invention, the damper control means electromagnetically drives the actuator in accordance with the oil pressure of the first oil passage, and directly fixes the accumulator connected to the shock absorber oil passage. -Since the clutch is released, the oil pressure can be rapidly increased without delay in response after the shift is completed, thereby enabling fine-grained hydraulic control with excellent responsiveness.
According to the fourth aspect of the present invention, the hydraulic control device includes the accumulator which communicates with the first oil passage which supplies and discharges the hydraulic pressure to and from the fastening element, and which absorbs the overshoot of the hydraulic pressure generated after the completion of the piston stroke of the fastening element. In the above, the first set time elapses after the stroke of the piston of the fastening element is completed from a state in which no hydraulic pressure is applied to the fastening element, which is disposed in a buffer oil passage that communicates the first oil path and the accumulator. Until the opening of the damper function of the accumulator by opening the oil path for the shock absorber and disabling the damper function of the accumulator by closing the oil path for the buffer after the first set time has elapsed, In this valve, when the second set time has elapsed after the completion of the stroke of the piston of the fastening element, the valve is stored in the accumulator. It is provided with the discharge means for discharging, while avoiding a response delay while suppressing pressure overshoot can be prevented oil backflow from the accumulator 6 at the time of releasing the fastening element 1.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic structure of a first embodiment according to the present invention.
FIG. 2 is a diagram for explaining the operation of the first embodiment.
FIG. 3 is a diagram for explaining a second embodiment.
FIG. 4 is a diagram for explaining a second embodiment.
FIG. 5 is a diagram showing a state A in the second embodiment.
FIG. 6 is a diagram showing a state B in the second embodiment.
FIG. 7 is a diagram showing a state C in the second embodiment.
FIG. 8 is a diagram for explaining the operation of the second embodiment.
FIG. 9 is a diagram for explaining a modified example corresponding to the second embodiment.
FIG. 10 is a diagram for explaining a modified example corresponding to the first embodiment.
FIG. 11 is a diagram for explaining a modified example corresponding to the first embodiment.
FIG. 12 is a diagram for explaining a modified example corresponding to the first embodiment.
FIG. 13 is a diagram for explaining a disadvantage of the conventional example.
FIG. 14 is a diagram for explaining a conventional example.
FIG. 15 is a diagram for explaining a conventional example.
[Explanation of symbols]
Reference Signs List 1 fastening element 1a piston 3 oil passage (first oil passage)
4 Orifice 5 Oil passage for damper (damper means)
6. Accumulator (damper means)
10. Oil passage (damper control means)
11 orifice (damper control means)
12 Cut valve (damper control means)
t5 First setting time t6 Second setting time

Claims (5)

In a hydraulic control device having a buffer oil passage branched and connected to a first oil passage that supplies and discharges hydraulic pressure to a fastening element and an accumulator connected to the buffer oil passage ,
Until a predetermined oil pressure is applied from a state where no oil pressure is applied to the fastening element and the first set time elapses, the oil passage for the shock absorber is opened to enable the damper action of the accumulator, and the first set time elapses. A hydraulic control device for an automatic transmission, further comprising: a damper control unit that shuts off the oil passage for the shock absorber and disables a damper function of the accumulator . A valve for shutting off and opening the shock absorber oil passage branched and connected to the first oil passage;
A second oil passage branched and connected to the first oil passage and having an orifice formed therein for applying an operating pressure corresponding to the oil pressure of the first oil passage to the valve. Item 2. A hydraulic control device for an automatic transmission according to Item 1 . Said damper control means, according to claim 1, wherein the first response to the hydraulic pressure in the oil passage electromagnetically drives the actuator, directly fixing and releasing the accumulator that is connected to the shock absorber fluid passage The hydraulic control device for an automatic transmission according to claim 1. A hydraulic control device having an accumulator that communicates with a first oil passage that supplies and discharges hydraulic pressure to a fastening element and absorbs an overshoot of hydraulic pressure that occurs after a piston stroke of the fastening element is completed.
The first oil passage is arranged in a shock absorber oil passage that communicates with the accumulator, from a state in which no hydraulic pressure is applied to the fastening element until a first set time elapses after the completion of the piston stroke of the fastening element. A valve is provided for opening the oil passage for the shock absorber to enable the damper action of the accumulator, and for shutting off the oil passage for the shock absorber after the lapse of the first set time to disable the damper action of the accumulator,
A hydraulic control device for an automatic transmission, characterized in that the valve is provided with a discharge means for discharging oil stored in the accumulator when a second set time has elapsed after completion of the stroke of the piston of the fastening element. The hydraulic control device for an automatic transmission according to claim 4, wherein the first set time is set longer than the second set time.

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