JP3102207B2 - Hydraulic control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control apparatus for an automatic transmission for electronically controlling the engagement pressure of a friction engagement element engaged in a drive range.

[0002]

2. Description of the Related Art The present applicant has previously filed Japanese Patent Application No. 4-85347.
No. (filed on April 7, 1992), a one-way clutch was abolished to reduce the size of the power train and simplify the control valve, and the automatic transmission controlled the engagement pressure of the friction engagement element directly with the electro-hydraulic control valve. The hydraulic control device of the machine was proposed.

In the prior application (FIG. 6), the line pressure is applied directly to the electrohydraulic control valve 7 of the frictional engagement element B2 among the frictional engagement elements C1 and B2 which are engaged at the first speed without passing through the manual valve 4. As a guide, the manual hydraulic pressure control valve 15 passes through the manual valve 4 to the electro-hydraulic control valve 15 of the frictional engagement element C1, and the D-range pressure is supplied to the electro-hydraulic control valve 15 only when the D-range is selected. Then, since the D range pressure from the manual valve 4 is drained to a position other than the D range (for example, the N range), the supply pressure to the electronic hydraulic control valve 15 is not generated even if the electronic hydraulic control valve 15 is out of order. .

[0004] As a result, a gear forward stage is not formed in a range other than the D range, and fail-safe in the event of a failure of the electronic control valve is realized.

[0005]

However, in the above-described hydraulic control apparatus for an automatic transmission, the D range pressure is instantaneously drained from the manual valve 4 at the time of the selection operation from the D range to the N range. Friction fastening element C1
Since the electro-hydraulic control valve 15 cannot adjust the hydraulic pressure release, a large D → N select shock may occur.

On the other hand, conventionally, in order to solve such a problem, it is general to adjust the control pressure itself of the frictional engagement element C1 which is engaged in the D range first speed using an accumulator or the like.

In this case, however, the control pressure applied to the frictional engagement element C1 is changed during shifting in the D range by the electro-hydraulic control valve 15.
, The hydraulic response is greatly reduced due to the presence of an accumulator and the like in the control pressure oil passage. As a result, another problem that the shift shock becomes large occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. It is an object of the present invention to provide a hydraulic control apparatus for an automatic transmission which electronically controls the engagement pressure of a D-range friction engagement element. An object of the present invention is to prevent a select shock when selecting from the D range to the N range without affecting the shift hydraulic control response to the friction engagement element engaged during the range.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, a hydraulic control apparatus for an automatic transmission according to the present invention provides a hydraulic control device which is responsive to a D range while ensuring a hydraulic supply to an electronic hydraulic control valve. A delay means for delaying the release of the drive range pressure from the electro-hydraulic control valve at the time of the selection operation to the range is provided in the branch oil passage of the drive range pressure oil passage or the drive range pressure drain oil passage.

That is, as shown in the claim correspondence diagram of FIG. 1, according to the first aspect of the present invention, the line pressure from the line pressure oil passage a is changed to the drive range pressure oil passage b by a selection operation to the drive range. a guidance, de from the drive range pressure oil channel b by a select operation to the neutral range
A manual valve c for draining the live range pressure from the drive range pressure drain oil passage h, and one common oil passage b2 connecting the manual valve c and the branch point b1
And a drive range pressure oil passage b including a plurality of branch oil passages b3 branched from a branch point b1, and a drive range pressure oil passage b3 provided in the branch oil passage b3 of the drive range pressure oil passage b. the control pressure in the regulated pressure by guiding the control pressure oil passage e of the frictional engagement elements d and a plurality of electro-hydraulic control valve f, provided common oil passage b2 of the drive range pressure oil passage b, when a drive range is selected, Manual valve c
A check valve i for ensuring a line pressure supply which does not cause a delay to the electro-hydraulic control valve f, and the check valve i are provided in parallel, and the electro-hydraulic control is performed during a select operation from the drive range to the neutral range. Do from valve f
And delay means g for delaying the release of the live range pressure .

According to the second aspect of the present invention, the line pressure from the line pressure oil passage a is led to the drive range pressure oil passage b by a selection operation to the drive range, and the drive range pressure is selected by a selection operation to the neutral range. Oil path b
A manual valve c for draining the drive range pressure from the drive range pressure drain oil passage h, one common oil passage b2 connecting the manual valve c and the branch point b1, and a plurality of branches branching from the branch point b1 Oil passage b3
, And a drive range pressure oil passage b and a branch oil passage b3 of the drive range pressure oil passage b. The drive range pressure is adjusted to a control pressure by an external control command to control the friction engagement element d. A plurality of electro-hydraulic control valves f leading to the pressure oil passage e, and a drive range pressure drain oil passage h, which are provided in the drive range pressure drain oil passage h to prevent the drive range pressure from being drained from the manual valve c during the selection operation from the drive range to the neutral range. Delay means g for delaying;
It is characterized by having. The delay means g
May be composed of only an orifice or a combination of an orifice and an accumulator.

[0012]

When selecting from the N range to the D range, the line pressure from the line pressure oil passage a is supplied to the common oil passage b2 of the drive range pressure oil passage b via the manual valve c, and is branched from the branch point b1. dry from a plurality of electro-hydraulic control valve f in the branched oil passage b3 provided in the branch oil passage b3 that
A control pressure is generated based on the brake pressure as a base pressure. The control pressure is guided to the friction engagement element d via the control pressure oil passage e, and the friction engagement element d at the time of starting is engaged.

At this time, the delay means g used when selecting from the D range to the N range is arranged such that the check valve i is arranged in parallel with the branch oil passage b3 of the drive range pressure oil passage b. In the second aspect of the present invention, since the control pressure is provided in the drive range pressure drain oil passage h, the control pressure from the electro-hydraulic control valve f generated based on the drive range pressure as the base pressure does not cause a response delay. Road e
Is supplied to the frictional engagement element d via the control unit, so that the shift hydraulic control response to the frictional engagement element d during the D range is ensured.

When selecting from the D range to the N range, the oil pressure in the drive range pressure oil passage b is drained via the manual valve c. delay means g to branch oil passage b3 of b is provided in the second aspect of the present invention, by delaying the drive range pressure drain oil passage h means g is arranged, from all electrohydraulic control valve f Drive range
The release of the pressure is delayed, and all the frictional engagement elements d fastened at the D range position are not released immediately upon selection to the N range, but the fastening pressure is temporarily maintained. , Which is released with a decrease in the hydraulic pressure that slowly decreases.

[0015] The dry pressure from all the electro-hydraulic control valves f
Delay the release of the blending pressure without defining the order
With this operation, the D → N select shock is reduced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) The configuration will be described. FIG. 2 is an overall schematic diagram showing a hydraulic control device for an automatic transmission according to a first embodiment corresponding to the first and third aspects of the present invention. The device of the first embodiment has a forward 6-speed reverse 1
Applied to powertrains that gain speed. Hereinafter, the drive range is abbreviated as the D range, the reverse range is abbreviated as the R range, and the neutral range is abbreviated as the N range.

In FIG. 2, C1, C2, B1, B2,
B3 is a friction fastening element, 1 is a manual valve, 2, 3,
4, 5, and 6 are electro-hydraulic control valves, 7, 8, and 9 are shuttle ball valves, 10 is a line pressure oil passage, 11 is a D range pressure oil passage,
12 is an R range pressure oil passage, 13, 14, 15, 16, 17
Is a control pressure oil passage, 18 is a D range pressure drain oil passage, 19 is an R range pressure drain oil passage, 20 is an R range pressure delay means,
Reference numeral 21 denotes D range pressure drain delay means (corresponding to delay means g).

The frictional engagement element C1 is the first speed in the D range,
The forward clutch is engaged at the second, third, and fourth speeds, the friction engagement element C2 is a high clutch engaged at the fourth, fifth, and sixth speeds in the D range, and the friction engagement element B1 is three at the D range.
3 & 5 & reverse brakes engaged in the 5th and 5th gears and R range, friction engagement element B2 is engaged in 2 & 6 brakes in the 2nd and 6th gears of the D range, and friction engagement element B3 is engaged in 1st gear of the D range and the R range Low and reverse brakes.

The manual valve 1 guides the line pressure from the line pressure oil passage 10 to the D range pressure oil passage 11 by the selection operation from the N range to the D range, and the line pressure by the selection operation from the N range to the R range. The line pressure from the oil passage 10 is led to the R range pressure oil passage 12, and the supply pressure to the D range pressure oil passage 11 is drained via the D range pressure drain oil passage 18 by a selection operation from the D range to the N range. , R by selecting operation from R range to N range
The supply pressure to range pressure oil passage 12 is drained via R range pressure drain oil passage 19.

The electro-hydraulic control valves 2, 3, 4, 5, 6
Is a depressurizing duty solenoid valve that generates an optimum control pressure according to a shift mode according to a control command from an AT control unit (not shown) and sends out the control pressure oil passages 13, 14, 15, 16, 17 to each other. Electro-hydraulic control valve 2,
3, 4, and 5 use the D range pressure or R range pressure from the manual valve 1 as input pressure, and the electro-hydraulic control valve 6 uses the line pressure from the line pressure oil passage 10 as input pressure.

The shuttle ball valve 7 is provided at a connection portion of these oil passages when the electro-hydraulic control valve 4 changes the D range pressure and the R range pressure to the input pressure.

The R range pressure delay means 20 secures reverse running when the electro-hydraulic control valves 4 and 6 for generating the fastening pressure of the friction fastening elements B1 and B3 to be fastened at the R range position are fully closed, A means for smoothly controlling the rise of the hydraulic pressure and the release of the hydraulic pressure so as to prevent the select shock. The accumulator 20a and the first orifice 20
b, the second orifice 20c, the first check valve 20c, and the second check valve 20d. When the hydraulic pressure is not generated in at least one of the control pressure oil passages 15 and 17 in the R range, the shuttle The R range pressure of which the rise in oil pressure has been delayed by the switching operation of the ball valves 8 and 9 is changed to the friction engagement elements B1 and B2.
B3 to realize fail-safe when the electro-hydraulic control valves 4 and 6 fail fully.

The D range pressure drain delay means 21 comprises:
When selecting operation from D range to N range, D range 1
Means for delaying the release of the supply pressure to the electro-hydraulic control valve 2 of the friction engagement element C1 fastened to the D-range pressure oil passage 1
1 and a check valve 21a provided in the
orifice 21b provided in an oil passage bypassing a
And the orifice 21b are provided with an accumulator 21c arranged in series.

Next, the operation will be described.

[Fastening operation of each fastening element at each range position] Although the illustration of the power train of the automatic transmission is omitted,
By operating the friction engagement elements C1, C2, B1, B2, and B3 as shown in the engagement logic table of FIG. 3, an automatic shift of six forward speeds is achieved at the D range position.

That is, the first speed of the D range is achieved by the fastening of the fastening elements C1 and B3, the second speed of the D range is achieved by the fastening of the fastening elements C1 and B2, and the third speed of the D range is achieved by the fastening of the fastening elements C1 and B1. The fourth speed of the D range is achieved by the fastening of the fastening elements C1 and C2, the fifth speed of the D range is achieved by the fastening of the fastening elements C2 and B1, and the sixth speed of the D range is achieved by the fastening of the fastening elements C2 and B2. You.

In the N range position, the fastening element B3 is fastened only at a low vehicle speed or at a stop. Further, the R range is achieved by fastening the fastening elements B1 and B3.

[N range] At the time of the N range when the vehicle is stopped, the electro-hydraulic control valve 6 for producing the control pressure of the friction engagement element B3 reduces the line pressure to fasten the friction engagement element B3.

However, as shown in FIG. 2, the manual valve 1 communicates with the D range pressure oil passage 11 and the D range pressure drain oil passage 18 and communicates with the R range pressure oil passage 12 and the R range pressure drain oil passage 19. The other frictional fastening elements C
The electro-hydraulic control valves 2, 3, 4 and 5, which generate the control pressures of 1, C2, B1, and B2, are supplied with the manual pressure valve 1 for the D range pressure and the R range pressure, which are the supply pressures. Friction fastening elements C1, C2, B1, other than B3
B2 is not engaged, and the vehicle does not move forward or backward when the N range is selected.

[When selecting from N range to D range]
When the selection operation is performed from the N range state to the D range position, the D range pressure oil passage 11 is connected to the line pressure oil passage 10 by the manual valve 1, so that the friction engagement elements C1,
Electro-hydraulic control valve for producing control pressure of C2, B1, B2,
By controlling 3, 4, and 5, it is possible to fasten the friction fastening elements C1, C2, B1, and B2 other than the friction fastening element B3.

Here, looking at the supply pressure characteristic of the electro-hydraulic control valve 2 for producing the control pressure of the friction engagement element C1 engaged when selecting from the N range to the D range, the check valve 2
1a, the oil is supplied to the electro-hydraulic control valve 2 in the supply direction without passing through the orifice 21b, so that the accumulator 21c is charged with oil in a very short time.
As shown by the solid line characteristics in FIG. 4, the supply pressure characteristics that rise sharply immediately after the selection from the N range to the D range are shown.

Therefore, when the control pressure for the friction engagement element C1 is generated by the electro-hydraulic control valve 2, the hydraulic control can be performed without being restricted by the supply pressure.
As shown by the dotted line characteristic in FIG. 4, by controlling the control pressure to the friction engagement element C1 by controlling the supply pressure to be reduced, it is possible to prevent a select shock when selecting from the N range to the D range.

[When selecting from D range to N range]
Normally, the selection from the D range to the N range is performed while the vehicle is stopped, and immediately before the selection, hydraulic pressure is supplied to the friction engagement elements C1 and the friction engagement elements B3 in the D range first speed state, so that both friction engagement elements C1 , B3 are in a fastening state.

In this state, when a select operation from the D range to the N range is performed, the D range pressure becomes
The supply pressure to the electro-hydraulic control valve 2 is instantaneously reduced by being drained, but the check valve 21a closes in the drain direction of the oil, so that the electro-hydraulic control valve 2 is charged by the oil charged in the accumulator 21c. The supply pressure to the pressure is maintained.

That is, the supply pressure to the electro-hydraulic control valve 2 is maintained until the oil in the accumulator 21c is completely discharged through the orifice 21b, and as shown by the solid line characteristics in FIG. It shows the characteristic that the oil pressure gradually decreases due to the spring characteristic.

At this time, if the maximum pressure command is issued to the electro-hydraulic control valve 2, the control pressure to the friction engagement element C1 becomes equal to the supply pressure to the electro-hydraulic control valve 2, so that the accumulator 21c Is realized, and a sharp decrease in the fastening force can be prevented. That is, the select shock from the D range to the N range is reduced.

Next, the effects will be described.

(1) Friction fastening elements C1, C2, B1, B
In the hydraulic control device of the automatic transmission for electronically controlling the engagement pressures of B2 and B3, when the select operation is performed from the D range to the N range, the release of the supply pressure to the electrohydraulic control valve 2 is delayed.
Since the range pressure drain delay means 21 is provided on the supply side of the electro-hydraulic control valve 2, the range pressure drain delay means 21 is selected when selecting from the D range to the N range without affecting the shift hydraulic control response by the electro-hydraulic control valve 2 during the D range. Shock can be prevented.

Here, for example, when a delay means is provided in the control pressure oil passage 13 connecting the electrohydraulic control valve 2 and the friction engagement element C1, D → N select shock can be prevented, In response to a control command at the time of a normal D range shift, the delay means may cause a delay in a rise response of the hydraulic pressure, thereby impairing the hydraulic response of the friction engagement element C1 and exacerbating a shift shock. As described above, the hydraulic response to the friction engagement element has a great effect on the speed change performance.

(2) D range pressure drain delay means 21
Is connected to a check valve 21 a provided in the D range pressure oil passage 11.
And an orifice 21b provided in an oil passage that bypasses the check valve 21a, and an accumulator 21c arranged in series with the orifice 21b.
When N is selected, the supply pressure characteristic of the electro-hydraulic control valve 2 becomes a hydraulic characteristic having a shelf pressure, and the occurrence of a select shock can be effectively suppressed.

(3) D range pressure drain delay means 21
Is provided only on the supply side of the electro-hydraulic control valve 2 of the friction engagement element C1 that is engaged in the first D-range, so that the other hydraulic engagement elements C2, B1, and B2 that are engaged by the D-range pressure have hydraulic control. Has no effect.

(Second Embodiment) The configuration will be described. FIG. 6 is an overall schematic diagram showing a hydraulic control device for an automatic transmission according to a second embodiment corresponding to the first and third aspects of the present invention.

While the device of the first embodiment is an example in which only the supply pressure to the electro-hydraulic control valve 2 is held by the accumulator 21c, the device of the second embodiment is such that the entire D range pressure is controlled by the accumulator 21c. This is an example in which the pressure is maintained.

That is, the configuration is different from that of the first embodiment in that the check valve 21a of the D range pressure drain delay means 21 is provided in the D range pressure oil passage 11 immediately after exiting from the manual valve 1. The other configuration is the same as that of the first embodiment, and the description is omitted.

Next, the operation will be described.

At the time of stop, for example, even if the D → N select operation is performed from the state where the second-speed friction engagement elements C1 and B2 of the D range are engaged, both the engagement pressures of the friction engagement elements C1 and B2 are equal to the shelf pressure. As a result, the D → N select shock can be prevented by gradually lowering the pressure and preventing the sudden pressure drop.

Next, the effects will be described.

In addition to the effects of the first embodiment, as described above,
Friction fastening elements C1, C2, B fastened at D range pressure
Since all the supply pressures 1 and B2 can be held at the time of D → N selection, the present invention can be applied to an automatic transmission that can be switched to a first speed, a second speed, or a mode in which the vehicle can start at another gear position. There is.

(Third Embodiment) The configuration will be described.

FIG. 7 is an overall schematic diagram showing a hydraulic control device for an automatic transmission according to a third embodiment corresponding to the first and third aspects of the present invention.

In the first embodiment, the accumulator 21c is used for the D range pressure drain delay means 21. On the other hand, in the third embodiment, the delay circuit is constituted only by the orifice 21b without using the accumulator 21c. It is. The other configuration is the same as that of the first embodiment, and the description is omitted.

Next, the operation will be described.

In the third embodiment, since the accumulator 21c is not used, the shelf pressure characteristic cannot be obtained as the supply pressure characteristic of the electro-hydraulic control valve 2 when D → N is selected, but the outflow is restricted by the orifice 21b. The characteristic that the supply pressure decreases slowly by the action is obtained. When the rigidity of the piston support and the rigidity of the piston chamber casing of the frictional engagement element C1 are low, this method can sufficiently obtain the effect of reducing the D → N select shock.

The effects of the first embodiment are as follows.
In addition to the effect of (3), since the accumulator 21c is not used, the configuration is simple and inexpensive.

(Fourth Embodiment) The configuration will be described.

FIG. 8 is an overall schematic diagram showing a hydraulic control apparatus for an automatic transmission according to a fourth embodiment corresponding to the second and third aspects of the present invention.

In the first to third embodiments, the orifice 21b of the D-range pressure drain delay means 21 is provided in the D-range pressure oil passage 11 between the manual valve 1, the electro-hydraulic control valve 2, and the like. The fourth embodiment is an example in which the orifice 21b of the D range pressure drain delay means 21 is provided in the D range pressure drain oil passage 18. The other configuration is the same as that of the first embodiment, and the description is omitted.

Next, the operation will be described.

In the device of the fourth embodiment, when N → D is selected, the line pressure oil passage 10 and the D range pressure oil passage 11 are connected, and at this time, the orifice 21b of the D range pressure drain delay means 21 is connected to the D range pressure. Since the D range pressure drain delay means 21 is provided in the drain oil passage 18, the D range pressure drain delay means 21 does not become any hydraulic pressure delay element, for example, the friction engagement element C1.
The characteristic that the supply pressure of the electro-hydraulic control valve 2 of FIG.
Hydraulic control response in the range is ensured.

When D → N is selected, the orifice 21b
Regulates the drain flow rate of D range pressure,
After the D → N selection, the D range pressure gradually decreases, and the hydraulic pressure for engaging the friction engagement element C1 and the like becomes equal to the D range pressure, so that the D → N select shock can be reduced.

As the effect, in addition to the effect of (1) of the first embodiment and the effect of applying the second-speed start AT of the second embodiment, when the D-range pressure oil passage 11 is provided with the D-range pressure drain delay means 21 As described above, since the check valve 21a for ensuring the hydraulic control response in the D range does not need to be used, the configuration is extremely simple and inexpensive.

(Fifth Embodiment) The configuration will be described.

FIG. 9 is an overall schematic diagram showing a hydraulic control device for an automatic transmission according to a fifth embodiment corresponding to the second and third aspects of the present invention.

While the D-range pressure drain delay means 21 of the fourth embodiment is a means using only the orifice 21b, the fifth embodiment has a D-range pressure drain delay This is an example in which an orifice 21b provided in the pressure drain oil passage 18 and an accumulator 21c provided in the D range pressure oil passage 11 are provided. still,
The other configuration is the same as that of the first embodiment, and the description is omitted.

Next, the operation will be described.

In the fifth embodiment, when N → D is selected, the line pressure oil passage 10 and the D range pressure oil passage 11 are connected, and at this time, the accumulator 21c is connected to the D range pressure oil passage 1
1, the friction fastening element C1 shown in FIG.
The supply pressure of the electro-hydraulic control valve 2 is increased by the same characteristic as the supply pressure characteristic of the electro-hydraulic control valve 2 to ensure the hydraulic control response in the D range.

When D → N is selected, the accumulator 2
1c creates a shelf pressure characteristic and the orifice 21b
Regulates the drain flow rate of D range pressure,
After the D → N select, the D → N select shock is effectively reduced because the D range pressure gradually decreases due to the characteristic having the shelf pressure, and the hydraulic pressure at which the friction engagement element C1 and the like are also equalized to this hydraulic characteristic. can do.

As the effect, in addition to the effect of the fourth embodiment,
D → N select shock can be effectively reduced.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to the embodiment, and even if there are changes and additions without departing from the scope of the invention, the invention is included in the invention. It is.

For example, in the embodiment, an example is shown in which only the orifice and the accumulator or the orifice are used as the delay means, but the D range pressure is controlled by the optimal oil pressure drop characteristic for reducing the shock when D → N is selected. For example, a means that uses a control valve may be used.

The delay means by the orifice 21b may be built in the D range pressure drain passage at the N range position in the manual valve 1.

[0073]

As described above, according to the present invention, in a hydraulic control apparatus for an automatic transmission for electronically controlling the engagement pressure of a D range friction engagement element, when a select operation from a D range to an N range is performed, Driving from electro-hydraulic control valve
According to the first aspect of the present invention, the delay means for delaying the release of the flange pressure is provided in the branch oil passage of the drive range pressure oil path in parallel with the check valve, and in the second aspect of the invention, the drive range pressure drain is provided. Since it is provided in the oil passage, it does not affect the shift hydraulic control response to the friction engagement element that is engaged in the D range, and when selecting from the D range to the N range , all friction engagement elements are selected without specifying the order. Hydraulic
By delaying the disconnection, the effect of preventing the select shock can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims of a hydraulic control device for an automatic transmission according to the present invention.

FIG. 2 is an overall schematic diagram illustrating a hydraulic control device of the automatic transmission according to the first embodiment.

FIG. 3 is a diagram showing a shift engagement logic table of the first embodiment device.

FIG. 4 is a diagram illustrating a supply pressure characteristic to the electro-hydraulic control valve 2 and a control pressure characteristic diagram of the frictional engagement element C1 when selecting N → D in the first embodiment.

FIG. 5 is a characteristic diagram of supply pressure to the electro-hydraulic control valve 2 at the time of D → N selection in the first embodiment device.

FIG. 6 is an overall schematic diagram showing a hydraulic control device for an automatic transmission according to a second embodiment.

FIG. 7 is an overall schematic diagram showing a hydraulic control device for an automatic transmission according to a third embodiment.

FIG. 8 is an overall schematic diagram showing a hydraulic control device for an automatic transmission according to a fourth embodiment.

FIG. 9 is an overall schematic diagram showing a hydraulic control device for an automatic transmission according to a fifth embodiment.

[Explanation of symbols]

a Line pressure oil passage b Drive range pressure oil passage b1 Branch point b2 Common oil passage b3 Branch oil passage c Manual valve d Friction engagement element e Control pressure oil passage f Electro-hydraulic control valve g Delay means h Drive range pressure drain oil passage i Check valve

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (3)

(57) [Claims] A line pressure from a line pressure oil passage is guided to a drive range pressure oil passage by a selection operation to a drive range, and a drive range pressure from the drive range pressure oil passage is converted to a drive range pressure by a selection operation to a neutral range. A manual valve that drains from a drain oil passage; one common oil passage that connects the manual valve to a branch point; a drive range pressure oil passage that includes a plurality of branch oil passages that branch from the branch point; A plurality of electro-hydraulic control valves provided in each of the branch oil passages of the oil passage, adjusting a drive range pressure to a control pressure by an external control command, and guiding the drive range pressure to a control pressure oil passage to a friction engagement element; Installed in the common oilway
At the time of selecting the Evrange , a check valve that ensures line pressure supply without delay from the manual valve to the electro-hydraulic control valve, and the check valve are provided in parallel, and when selecting operation from the drive range to the neutral range, And a delay means for delaying release of drive range pressure from the electro-hydraulic control valve. A hydraulic control apparatus for an automatic transmission, comprising: 2. A line pressure from a line pressure oil passage is guided to a drive range pressure oil passage by a selection operation to a drive range, and a drive range pressure from the drive range pressure oil passage is converted to a drive range pressure by a selection operation to a neutral range. A manual valve that drains from a drain oil passage; one common oil passage that connects the manual valve to a branch point; a drive range pressure oil passage that includes a plurality of branch oil passages that branch from the branch point; A plurality of electro-hydraulic control valves provided in each of the branch oil passages of the oil passage, adjusting a drive range pressure to a control pressure by an external control command, and guiding the drive range pressure to a control pressure oil passage to a friction engagement element; It is installed in the drain oil passage, and when selecting from the drive range to the neutral range, the manual valve Drive range to drain
A hydraulic control device for an automatic transmission, comprising: delay means for delaying pressure release. 3. The automatic transmission hydraulic control device according to claim 1, wherein said delay means comprises only an orifice or a combination of an orifice and an accumulator. Transmission hydraulic control unit.