JPH02113150A - Hydraulic control device for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent internal locking at speed change by providing a changeover means to change over into communicated condition to a branch oil passage on the second friction coupling element side, when oil pressure to a release chamber on the first friction coupling element side becomes over the prescribed pressure. CONSTITUTION:At 2-3 shift-up speed change, oil pressure is supplied to a release port 45b' through a support release line 126. When the oil pressure in the support release line 126 rises over the prescribed pressure, a 2-4 brake is surely released through a hydraulic actuator 45'. At this time, the spool 83a of a coast control valve 83 is positioned on the right side of the figure, the oil pressure in the support release line 126 is supplied to a coast clutch line 128, and the coast clutch 42 is coupled. Hereby, such internal locking that the coast clutch 42 is coupled before surely releasing the 2-4 brake, can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a hydraulic control device for an automatic transmission.

``Prior Art'' In general, automatic transmissions installed in automobiles combine a torque converter and a speed change gear mechanism, and selectively operate multiple friction engagement elements such as clutches and brakes through the power transmission path of the speed change gear mechanism. It is designed to automatically shift to a predetermined gear position by switching the gear position. here,
The plurality of friction engagement elements include four clutches: a reverse clutch, a forward clutch, a coast clutch, and a 3-4 clutch, and two brakes: a 2-4 brake and a low reverse brake. Two one-way clutches are provided, and by changing the combination of these friction engagement elements and one-way clutches, predetermined gears in the drive range (D range), 2 range, lunge, and reverse range (R range) can be set. It is now possible to obtain it.

This type of automatic transmission is provided with a hydraulic control circuit that controls the supply and discharge of hydraulic pressure to and from the actuators of the respective friction engagement elements. This hydraulic control circuit includes a regulator valve that adjusts the discharge pressure of the oil pump to a predetermined line pressure, a manual valve that changes the range by manual operation, and an actuator for each of the frictional engagement elements that operates according to the operating state. It is comprised of a plurality of shift valves that selectively operate a plurality of frictional engagement elements by switching oil passages, and various valves that perform other auxiliary functions.

Note that such a hydraulic control circuit is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 1986-
This is disclosed in Japanese Patent No. 246652, and in the hydraulic control circuit of this publication, the shift valve is driven by a solenoid valve, so that the shift control is adapted to the operating condition and performed with higher precision.

"Problem to be Solved by the Invention" In automatic transmissions, the timing of the engagement or release operation of the friction engagement elements during each gear shift is important for obtaining a good gear shift operation. If the element is engaged too quickly or the friction engagement element to be released is released too slowly, the transmission mechanism is temporarily locked and the output torque decreases.

For example, considering a 2-3 upshift, in 2nd gear, the 2-4 brake is engaged, and the 3-4 clutch and coast clutch are released, but in 3rd gear, the 2-4 brake is engaged, and the 3-4 clutch and coast clutch are released. The brake is released, and the 3-4 clutch and coast clutch are engaged. The coast clutch is engaged to prevent the one-way clutch from idling when the engine is engaged.
If the timing of the coast clutch engagement operation is too early when shifting from 3rd gear to 3rd gear, the coast clutch will be engaged before the 2-4 brake is reliably released. Such a state is called an internal lock, and it is desired to prevent this internal lock state.

An object of the present invention is to provide a hydraulic control device for an automatic transmission that can reliably prevent internal locking during gear shifting with a simple configuration.

"Means for Solving the Problems" The present invention provides a speed change gear mechanism, a plurality of friction engagement elements for switching the power transmission path of the speed change gear mechanism, and a plurality of oil passages each communicating with these friction engagement elements. In the hydraulic control device for an automatic transmission, the plurality of frictional engagement elements include a hydraulic control circuit provided therein, and configured to change gears by switching the respective oil passages, the plurality of frictional engagement elements having a coupling chamber and a release chamber. The release chamber of the first frictional engagement element and the working chamber of the second frictional engagement element are provided with a common oil. A branch oil passage branched from the road is connected, and the branch oil passage on the second friction engagement element side is connected to the branch oil passage when the hydraulic pressure to the release chamber of the first friction engagement element becomes equal to or higher than a predetermined pressure. It is characterized in that a switching means for switching is provided.

"Function" In the present invention, a switching means is provided in the branch oil passage on the side of the second frictional engagement element, and this switching means
When the hydraulic pressure to the release chamber of the friction engagement element becomes equal to or higher than a predetermined pressure and the friction engagement element 'M1 is reliably released, it switches to a communicating state, and as a result, the working chamber of the second friction engagement element Hydraulic pressure is supplied to fasten the second frictional fastening element. In this way, the second frictional engagement element is engaged after the first frictional engagement element is reliably released, thereby ensuring that the internal lock, that is, the first frictional engagement element is released. This prevents an internal lock state in which the second frictional fastening element is fastened before the second frictional fastening element is fastened.

"Embodiments" Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

First, FIG. 1 shows the mechanical configuration of an automatic transmission.

In FIG. 1, automatic transmission 10 includes a torque converter 20 and a speed change gear mechanism 30 driven by the output of converter 20. As shown in FIG. The mechanism 30 is provided with a plurality of frictional engagement elements 41 to 46 such as clutches and brakes that switch the power transmission path, and one-way clutches 51 and 52, and these act as driving ranges such as driving range, driving range, and driving range.
．． 1 and R ranges, 1st to 4th speeds in the D range, 1st to 3rd speeds in the 2nd range, and 1st to 2nd speeds in Lunge are available.

The torque converter 20 includes a pump 22 fixedly installed in a case 21 connected to the engine output shaft 1, and a turbine 23 disposed opposite to the pump 22 and driven by the pump 22 via hydraulic oil. , a stator 25 that is interposed between the pump 22 and the turbine 23 and supported by the transmission case 11 via the one-way clutch 24 to increase torque; and the case 21 and the turbine 2
3 and directly connects the engine output shaft 1 and the turbine 23 via the case 21. The rotation of the turbine 23 is outputted to the transmission gear mechanism 30 via the turbine shaft 27. Here, a pump shaft 12 passing through a turbine shaft 27 is connected to the engine output shaft 1, and the shaft 12 allows
An oil pump 13 provided at the rear end of the transmission is driven.

The speed change gear mechanism 30 is comprised of a Ravigneau-type planetary gear device. That is, the mechanism 30 includes a small sun gear 31 with a small diameter that is loosely fitted onto the turbine shaft 27, and a large sun gear 32 with a large diameter that is also loosely fitted on the turbine shaft 27 behind the sun gear 31.
, a plurality of short pinion gears 33 meshed with the small sun gear 31, a long pinion gear 34 whose front half meshed with the short pinion gear 33 and whose rear half meshed with the large sun gear 32; A carrier 35 rotatably supports the short pinion gear 33, and a ring gear 36 meshed with the front half of the long pinion gear 34.
It consists of

Then, the turbine shaft 27 and the small sun gear 31
A forward clutch 41 and a first one-way clutch 51 are interposed in series between the two clutches 41 and 51, and a coast clutch 42 is further interposed in parallel with these clutches 41 and 51. A reverse clutch 44 is interposed between the turbine shaft 27 and the large sun gear 32, and a reverse clutch 44 is provided between the large sun gear 32 and the reverse clutch 44 to which the large sun gear 32 is fixed and which is composed of a band brake. -4 brake 45 is provided.

Between the turbine shaft 27 and the carrier 35, there is a 3-
A 4-way clutch 43 is interposed between the carrier 35 of the 3-4 clutch 43 and the transmission case 11, and a second one-way clutch 52 that receives the reaction force of the carrier 35 and the carrier 35 are fixed. A low reverse brake 46 is provided in parallel. And the ring gear 3
6 is connected to an output gear I4, and rotation is transmitted from the output gear 14 to left and right wheels (not shown) via a differential device.

Next, the frictional engagement elements 41 such as the above-mentioned clutches and brakes
46 and one-way clutches 51 and 52, and the relationship between the gear positions and the gear positions will be explained.

First, in first gear, the forward clutch 41 is engaged, and the first and second one-way clutches 51, 52
becomes locked. For this reason, the torque converter 20
The output rotation is manually input from the turbine shaft 27 to the small sun gear 31 of the planetary gear unit 30 via the forward clutch 41 and the first one-way clutch 51. In this case, since the carrier 35 is fixed by the action of the second one-way clutch 52, the planetary gear device 30 operates in a differential manner to transmit rotation from the small sun gear 31 to the ring gear 36 via the short pinion gear 33 and the long pinion gear 34. It operates as a fixed gear train that does not perform As a result, a first speed state with a large reduction ratio corresponding to the ratio of the diameters of the small sun gear 31 and the ring gear 36 is obtained.

Next, at 231A, the forward clutch 41 is engaged, the first one-way clutch 51 is locked, the 2-4 brake 45 is engaged, the large sun gear 32 in the planetary gear device 30 is fixed, and the first one-way clutch 51 is engaged. 2 one-way clutch 52 becomes idle. Therefore, the rotation transmitted from the turbine shaft 27 to the small sun gear 31 is transmitted to the short pinion gear 3.
3 to the long pinion gear 34, and since the large sun gear 32 that meshes with the long pinion gear 34 is fixed, the long pinion gear 34 revolves on the large sun gear 32, and the carrier 35 rotates accordingly. As a result, the rotation of the ring gear 36 is increased by the rotation amount of the carrier 35 (revolution of the long pinion gear 34) compared to the first speed state, and a second speed state is obtained in which the reduction ratio is smaller than that in the first speed state.

Further, in the third speed, the 2-4 brake 45 is released from the second speed state, and at the same time, the 3-4 clutch 43 is engaged. Therefore, the rotation of the turbine shaft 27 is controlled by the forward clutch 41 and the first one-way clutch 51.
At the same time, it is input to the small sun gear 31 via
It is also input to the carrier 35 via the 3-4 clutch 43. As a result, the entire planetary gear device 30 rotates integrally, and the ring gear 36 rotates around the turbine shaft 2.
A 3rd speed state is obtained in which the motor rotates at the same speed as 7.

Furthermore, in 4th gear, the 2nd gear that was once released in 3rd gear is
-4 Brake 45 is re-engaged. Therefore, the rotation of the turbine shaft 27 is manually applied from the 3-4 clutch 43 to the carrier 35 of the planetary gear device 30, causing the long pinion gear 34 to revolve. Since the long pinion gear 34 is fixed by the 2-4 brake 45, it rotates while revolving together with the carrier 35. As a result, the ring gear 36 meshing with the long pinion gear 34 rotates (
Long pinion gear 3 (rotation of turbine shaft 27)
The rotation speed will be increased by the amount of 4 in-house speed, thereby obtaining 4th speed in an overdrive state. In this case, the forward clutch 41 is in the engaged state, but the first one-way clutch 51 in series with the forward clutch 41 is in the engaged state.
is in an idling state, and the coast clutch 42 is
Since it is not fastened, the rotation of the turbine shaft 27 is not input to the small sun gear 31.

Furthermore, at reverse speed, the reverse clutch 44 and low reverse brake 46 are engaged, so the rotation of the turbine shaft 27 is input to the large sun gear 32 of the planetary gear device 30, and the carrier 35 of the gear device 30 is fixed. Ru. For this reason, large sun gear 32
The rotation is transmitted through a fixed gear train extending from the rotor to the ring gear 36 via the long pinion gear 34, and a reduction ratio corresponding to the ratio of the diameters of the large sun gear 34 and the ring gear 36 is obtained. In this case, ring gear 3
6 is opposite to the rotation direction of the turbine shaft 27 and large sun gear 32, so that a backward state is obtained.

Note that the first one-way clutch 51, which transmits rotation in 1st to 3rd gears, and the second one-way clutch 52, which receives no reaction force in 1st gear, idle during coasting, so the engine brake does not operate in these gears. It turns out. However, 3rd gear in D range and 2nd gear in 2nd range.
In 3rd speed and 1.2 speed of lunge, the coast clutch 42 parallel to the first one-way clutch 51 is engaged, and in the 1st speed of lunge, the low reverse brake 46 parallel to the second one-way clutch 52 is engaged. Therefore, engine braking is obtained in these gears.

Table 1 summarizes the relationship between the operations of each of the hydraulic engagement elements 41 to 46 and one-way clutches 51 and 52 and each gear stage.

Next, FIG. 2 shows a hydraulic control circuit 60 that supplies and discharges hydraulic pressure to the actuators of each of the frictional engagement elements 41 to 46.
It is shown.

In FIG. 2, among the actuators, the hydraulic actuator 45' of the 2-4 brake 45 is composed of a servo piston having an apply boat 45a' and a release boat 45b'. And apply port 4
When hydraulic pressure is supplied only to port 5a', the 2-4 brake 45 is engaged, while both ports 45a' and 45b
' When hydraulic pressure is not supplied to both and both bows) 45
When hydraulic pressure is supplied to both a' and 45b', 2-
4 brake 45 is released. Also,
The actuators of the other frictional engagement elements 41 to 44 and 46 are constituted by ordinary hydraulic pistons, and are adapted to engage the frictional engagement elements when hydraulic pressure is supplied.

This hydraulic control circuit 60 includes main components from the oil pump 13 (see also FIG. 1) to the main line 1.
A regulator valve 61 adjusts the pressure of the hydraulic fluid discharged to a predetermined running pressure to a predetermined running pressure, a manual valve 62 performs range selection by manual operation, and each friction engagement element (actuator) operates according to the gear position. 41-4
Shift valves 63, 64, and 65 of 1-2, 2, 3, 3, and 4 for supplying and discharging hydraulic pressure to and from 6 are provided.

The manual valve 62 has a manual port e into which line pressure is introduced from the main line 110, and first to fourth output boats a to d, and by movement of the spool 62a, the manual port e is connected to the port D. The range and 2 ranges are connected to the first and second output ports a and b, the lunge is connected to the first and third output ports a and C, and the R range is connected to the fourth output port d. There is. and,
First to fourth output lines 111 to 114 are connected to each of the output ports a to d, respectively.

Also, 1-2.2-3.3-4 shift valve 63.64
．． 65 are the spools 63a164a, 6, respectively.
5a is biased toward the right side in the drawing by a spring (not shown), and these spools 63a, 64
On the right side of 65a is the pilot boat 63b.
, 64b, and 65b are provided. A first pilot line 115 led from the main line 110 is connected to the pilot boat 63b of the 1-2 shift valve 63.
are connected to the pilot boats 64b and 65b of the 2-3.3-4 shift valve 64.65, respectively.
Second and third pilot lines 117.118 branched from the output line 111 via line 116 are connected, respectively, and these pilot lines 115.1
17, 118 are provided with first, second, and third solenoid valves 66, 67, and 68, respectively. Each of these solenoid valves 66-68, when in the ON state, drains the pilot line 115, 117, 118 to discharge the pilot pressure in the pilot port 63b-65b of each corresponding shift valve 63-65. This positions the spools 63a to 65a on the right side in the drawing. On the other hand, the solenoid valves 66 to 68 are
When in the FF state, the pilot port 63
Each pilot line 115.117.11 from b to 65b
Pilot pressure is introduced from 8 to spools 63a to 6.
5a are respectively positioned on the left side in the drawing.

Here, these solenoid valves 66 to 68 operate based on a map preset according to the vehicle speed and engine throttle opening according to signals from the control circuit.
It is configured to be turned on and off. With the ON/OFF operation of the solenoid valves 66-68, the spools 63a-6 of each shift valve 63-65
The position of 5a is changed, and the oil passages leading to each of the frictional engagement elements 41 to 46 are changed. As a result, these frictional engagement elements 41 to 46 are engaged in the combinations shown in Table 1 above, and the gear stage can be changed according to the operating state. In this case, each gear stage and each solenoid valve 66 to 68 are turned on.

The relationship with the OFF state combination pattern is set as shown in Table 2. In addition, at the time of the 3-2 downshift, the shift is made through the intermediate pattern shown in the table.

Next, each output capo in the manual valve 62)
1st to 4th output lines 111 to 11 connected to a-d
4, in each of the forward ranges D and 2.1, a line 116 is branched from the first output line 111 that communicates with the main line 110, and this line 116 is used as a forward clutch line and is connected to the one-way orifice 71. is guided to the forward clutch 41 via. Therefore,
It is understood that in D12 and Lunge, the forward clutch 41 is always engaged. Here, the forward clutch line 116 is connected to an N-D accumulator 72 for buffering when the forward clutch is engaged via a line ]19.
is connected.

Further, the first output line 111 is connected to the 1-2 shift valve 6
3, and when the first solenoid valve 66 is turned on and the spool 63a is located on the right side, the first output line 111 is connected to the servo apply line 120.
The servo piston 45' is connected to the apply boat 45a' of the servo piston 45' via the one-way orifice 73. Therefore, D.

2. When the first solenoid valve 66 is in the ON state in the lunge, that is, in the D range, 2.3.4 speed, 2 in the 2nd range.
．． In 3rd gear and 2nd gear in Lunge, apply port 45a
Hydraulic pressure (servo apply pressure) is introduced at ′, and at this time,
When hydraulic pressure (servo release pressure) is not introduced into the release port 45b', the 2-4 brake 45 is engaged. In addition, the servo apply line 120
A 1-2 accumulator 74 is connected to the 1-2 accumulator 74 for buffering when the 2-4 brake is engaged.

Further, a second output line 112 communicating with the main line 110 in the D and 2 ranges is led to a 2-3 shift valve 64. When the second solenoid valve 67 is OFF and the spool 64a is located on the left side, this line 112 is connected to the 3-
4 clutch line 121.

Note that this line 121 further reaches the 3-4 clutch 43 via a one-way orifice 76. Therefore, D
, when the second solenoid valve 67 is in the OFF state in the 2nd range, that is, 3.4 speed in the D range and 3rd in the 2nd range.
At high speed, the 3-4 clutch 43 will be engaged.

Here, first and second drain lines 122 and 123 are branched from the 3-4 clutch line 121, and among these, the first drain line 122 is connected to the 3-4 shift valve 65.
When the third solenoid valve 68 is in the OFF state (the spool 65a is on the left side), it is connected to the line 124 and connected to the drain port of the 2-3 shift valve 64.

Further, the second drain line 123 is similarly guided to the 3-4 shift valve 65 via the one-way orifice 77, the fixed orifice 78, and the one-way orifice 79, and the third solenoid valve 68 is in the ON state (the spool 6
5a is on the right side), it connects to line 124 and connects 2-
It communicates with the drain port of the 3rd shift valve 64.

That is, during the 3-2 and 4-2 downshifts when the oil pressure (3-4 clutch pressure) is discharged from the 3-4 clutch 43, the third solenoid valve 68 shown in Table 2 is turned off.
During the 3-2 downshift via the intermediate pattern of the F state, the 3-4 clutch pressure is discharged through the first drain line 122, and the third solenoid valve 68 is turned on.
During a 4-2 downshift, the 3-4 clutch pressure is discharged through the second drain line 123. Note that there are three holes between the one-way orifice 77 and the fixed orifice 78 of the second drain line 123.
-2-3 accumulator 8 for buffering when the 4 clutch is activated
0 is connected.

In addition, the line 12 connected to the first drain line 122
Similarly to the 3-4 clutch line 121, the 2-3 shift valve 6 is operated when the second solenoid valve 67 is in the OFF state.
When the spool 64a of No. 4 is located on the left side, it communicates with the second output line 112. This line 125 is guided to the 3-4 shift valve 65, and communicates with the servo release line 126 when the third solenoid valve 68 is in the OFF state and the spool 65a is located on the left side. This line 126 is connected to the one-way orifice 81
．． 82 to the release port 45b' of the servo piston 45'. Therefore, D, the second
, when both the third solenoid valves 67 and 68 are in the OFF state, that is, in the 3rd speed of the D range and the 3rd speed of the 2nd range, servo release pressure is introduced into the release port 45b' of the servo piston 45', and the 2-4 Brake 45 is released.

Furthermore, a line 127 branched from between the two one-way orifices 81 and 82 of the servo release line 126.
is connected to the coast clutch line 128 via the coast control valve 83, one-way orifice 84, and ball valve 85, and the coast clutch 42
It has reached this point. Therefore, the coast clutch 42 is engaged in the 3rd speed of the D range and the 3rd speed of the 2nd range where hydraulic pressure is introduced into the servo release line 126.

On the other hand, when the third solenoid valve 68 is in the OFF state,
The spool 65a of the shift valve 65 is located on the left side, and the second solenoid valve 67 is in the ON state.
When the spool 64a of the 3-4 shift valve 64 is located on the right side, the forward clutch line 116 is connected to its branch line 129.3-4 shift valve 65, line 130.
and communicates with the line 131 via the 2-3 shift valve 64. This line 131 further communicates with the coast craft line 128 via a ball valve 85.

Therefore, in the coast clutch 42, the second solenoid valve 67 is in the ON state and the third solenoid valve 68 is in the ON state.
It is also engaged when is in the OFF state, that is, in the 2nd gear of the 2nd range and the 1.2nd gear of the lunge.

Further, the third output line 113, which is connected to the main line 110 by the manual valve 62, is connected to the low reducing valve 86 as a pressure reducing valve and the line 1.
32, it is led to the 1-2 shift valve 63. This line 132 is connected to the one-way orifice 87 and the ball valve 88 when the first solenoid valve 66 is in the OFF state and the spool 63a is located on the left side.
The low reverse brake line 133 is connected to the low reverse brake line 133 through the low reverse brake line 133 . Therefore, when the first solenoid valve 66 is in the FF state in lunge, that is,
In the first gear of the lunge, the low reverse brake 46 is engaged.

Furthermore, a fourth output line 114 that communicates with the main line 110 in the R range communicates with a low reverse brake line 133 via a line 134 branched from the line 114, a one-way orifice 89, and a ball valve 88. Furthermore, the fourth output line 114 becomes a reverse clutch line 135 and connects to the one-way orifice 90.
It reaches the reverse clutch 44 via. Therefore, in the R range, the low reverse brake 46 and reverse clutch 44 are always engaged. Note that the reverse clutch line 135 has an N- for buffering when the reverse clutch is engaged.
An R accumulator 91 is connected.

The hydraulic control circuit 60 is also provided with a lock-up shift valve 92 for operating the lock-up clutch 26 in the torque converter 20 shown in FIG. A torque converter line 136 from the regulator valve 61 is led to this valve 92, and a pilot port 92b provided at one end of the valve 92
A pilot line 137 is connected to the pilot line 137, which is branched from the main line 110 and introduces hydraulic pressure reduced by a solenoid reducing valve 93.

A fourth solenoid valve 94 for lock-up is provided on this line 137, and when the valve 94 is in the OFF state, the spool 92a is located on the right side, so that the torque converter line 136 is connected to the torque converter 2.
The internal pressure of the torque converter 20 increases and the lock-up clutch 26 is engaged. Also, the solenoid valve 94 is turned on and the spool 92a
moves to the left, the torque converter line 13
6 communicates with the lock-up release line 139 via the lock-up control pulse 192', and the LD pull-up release pressure in the torque converter 20 is introduced to release the lock-up clutch 26.

The hydraulic control circuit 60 also includes a throttle modulator valve 95 for controlling the line pressure adjusted by the regulator valve 61, a duty solenoid valve 96 for operating the valve, and a back valve (cuff). 97 is provided.

A line 140 branched from a line 137 leading to the main line 110 is led to the throttle modulator valve 95 via a solenoid reducing valve 93, and is adjusted by a duty solenoid valve 96 that opens and closes periodically. The pilot pressure thus generated is introduced into one end of the spool 95a, and the throttle modulator pressure is generated in accordance with the duty rate (valve open time ratio during one cycle) of the decorty solenoid valve 96. There is. In this case, the duty rate is set according to the throttle opening of the engine, and the corresponding throttle modulator pressure is introduced to the pressure booster boat 61a of the regulator valve 61 through the line 141, so that The line pressure adjusted by the valve 61 is increased in accordance with the increase in the throttle opening of the engine.

The cutback valve 97 also includes a line 1 that supplies throttle modulator pressure to the regulator valve 61.
A line 142 branched from 41 is led, and the first to third ports) 97 b.

97c and 97d are provided. 1st port 9, 7
A pilot pressure generated when the first solenoid valve 66 is in the OFF state is introduced into the second port 92C via a line 143.
The pilot pressure generated when the solenoid valve 67 is in the OFF state is introduced through the line 144, and the pilot pressure generated when the third solenoid valve 68 is in the OFF state is introduced into the third port 97d. Pilot pressure to be used is introduced via line 145.

Then, the spool 97a moves according to the introduction state of these pilot pressures, and the pilot pressure is introduced only to the first port 97b (only the first solenoid valve 66 is turned OFF).
In the 1st speed of the D range (in the FF state) and the 1st speed of the 2nd range, the line 142 is cut off, and the first and third ports 97b, 97
In the first gear of the lunge, where pilot pressure is introduced to d (the first and third solenoid valves 66, 68 are in the OFF state), the line 142 is cut off, and pilot pressure is introduced only to the third boat 97d. (Third solenoid valve 6
The line 142 is cut off in the 2nd gear of the 2nd range (only 8 is in the OFF state) and the 2nd gear of the lunge. On the other hand, at gears other than these, the line 142 is connected to a line 146, and the throttle modulator pressure is introduced into the pressure reduction port 61b of the regulator valve 61, thereby reducing the line pressure. .

In addition to the above configuration, this hydraulic control circuit 60 includes, in addition to the coast control valve 83, a bypass valve 101.2-3 control valve 102, for adjusting the supply and discharge timing of hydraulic pressure during each gear shift. A timing valve 103 is also provided.

As described above, the coast control valve 83 is provided on the line 127 that branches off from the servo release line 126 and leads to the coast clutch line 128 via the ball valve 85, and also on the line that branches off from the forward clutch line 116. 147,
Line pressure (forward clutch pressure) is guided to the other end of the spool 83a. Then, when the servo release pressure introduced into one end of the spool 83a by the line 127 and the biasing force of the spring (not shown) in the valve 83 overcome the line pressure from the line 147, the line 1
27 can be communicated.

Therefore, through this line 127, the coast clutch 4
During 2-3 upshifts in D range and 2 range where coast clutch pressure is supplied to 2, after the servo release pressure has sufficiently increased, that is, after the 2-4 brake 45 has been reliably released, coast clutch 42
will be concluded. Therefore, 2-4 brake 4
5 and coast clutch 42 are simultaneously engaged, an internal lock is prevented. Note that since line pressure is led to one end of the spool 83a, the timing of communicating the line 127 is changed in accordance with the line pressure, and the communication timing and the pressure level of the servo release pressure are The correspondence relationship can be set appropriately.

The bypass valve 101 is also provided on a bypass line 148 that bypasses the one-way orifice 76 provided in the 3-49 latch line 121. 3-
The hydraulic pressure (34 clutch pressure) downstream of the one-way orifice 76 of the 4-clutch line 121 is introduced into one end of the spool 101a of the bypass valve 101, and the modulator pressure led from the throttle modulator valve 95 through lines 149 and 150 is , the bypass valve 1
01 is introduced into the other end of the spool 101a. When the 3-4 clutch pressure rises above a predetermined value and the spool 101a moves to the left, the bypass line 14
It is designed to block 8.

Therefore, the 3-4 clutch pressure is quickly supplied by the bypass line 148 at the start of supply, but after that,
The one-way orifice 76 slows down the supply, thus adjusting the engagement timing of the 3-4 clutch 43 during the 2-3 upshift.

In addition, the 2-3 control valve 102 is a servo IJ
It is provided on the bypass line 151 that bypasses the one-way orifice 81 that performs a throttling action in the oil pressure supply direction on the lease line 126.

One end of the spool 102a of the valve 102 has a 3-4
The hydraulic pressure (3-4 clutch pressure) in the clutch line 121 is introduced, and the aforementioned throttle modulator pressure is introduced into the center of the spool 102a via the line 149 and line 152. 102a
The servo release pressure downstream of the bypass line 151 is introduced into the other end.

Then, by the action of the 3-4 clutch pressure, throttle modulator pressure, and servo release pressure, the bypass line 151 is opened or closed, and the servo release pressure is adjusted in response to the increase in the 3-4 clutch pressure. It has become.

On the other hand, the timing valve 103 has a first bypass line 153 that bypasses the one-way orifice 73 on the servo apply line 120, and a servo release line 1.
A second bypass line 154 bypassing the one-way orifice 82 (and 81) on 26 and a fixed orifice 7 in the second drain line 123 at 3-4 clutch pressure.
8 (and one-way orifice 79). A pilot line 157 led from the main line 110 via a line 156 is connected to one end of the spool 103a, and the line 157 is provided with a fifth solenoid valve 104.

This timing valve 103 is operated by the first to third bypass lines 15 by the operation of the fifth solenoid valve 104.
3.154.155 is opened and closed, 1-2 upshifting, 3-2 downshifting, and 4-2
This controls the timing of supplying and discharging hydraulic pressure during downshifts. Below, this timing valve 103
Specific operations during each gear shift will be explained.

First, during (1-2) upshifting, the first solenoid valve 66 is switched from the OFF state to the ON state, thereby moving the spool 63a of the 1-2 shift valve 63 from the left side to the right side.

Then, by communicating the first output line 111 with the servo apply line 120, servo apply pressure is supplied to the apply boat 458' of the servo piston 45' via the one-way orifice 73.
4 brake 45 will be engaged.

During this shift operation, the fifth solenoid valve 104 for operating the timing valve is first turned off at the start of the shift.
The state changes from the ON state to the ON state. Therefore, the spool 103a of the timing valve 103 moves to the right, and the first bypass line 153 that bypasses the one-way orifice 73 is communicated. Therefore, in the first half of the shift operation, the servo apply pressure is quickly supplied to the apply bow 45a'.

Then, when a predetermined period of time has elapsed from the start of the shift during the shift, the fifth solenoid valve 104 is switched from the ON state to the OFF state, and the spool 103a of the timing valve 103 is moved to the left and the first bypass is switched off. Line 153 is cut off. Therefore, in the latter half of the shift operation, the servo apply pressure is applied to the one-way orifice 7.
3 to the apply bow) 45a' of the servo piston 45'.

In this way, during the 1-2 upshift, the servo apply pressure changes differently in the first half and the second half of the shift operation, and in particular, at the beginning of the shift operation, the first bypass line 153 is connected. , the piston movement time is shortened, the time lag of the upshift operation is reduced, and in the latter half of the gear shift operation, due to the action of the one-way orifice 73 and the 1-2 accumulator 74,
This will result in smooth upshifts.

Next, during a 3-2 downshift in the D range, both the second and third solenoid valves 67 and 68
The second solenoid valve 6 is in the OFF state before the start of the shift operation, and the ON state after the shift operation is completed, but during the shift, the second solenoid valve 6
7 is turned ON, and the third solenoid valve 68 is turned OFF.
Becomes F state.

Therefore, during gear shifting, the spool 64a of the 2-3 shift valve 64 is located on the right side, and the spool 65a of the 3-4 shift valve 65 is located on the left side. Therefore, the servo release pressure that was being supplied to the release bow (45b') of the servo piston 45' is
Via line 125 and one-way orifice 75,
It will be discharged from the drain port 64c of the 2-3 shift valve 64.

During this shift, the fifth solenoid valve 104
Similarly to the above 1-2 upshift, the OFF state is first switched to the ON state at the start of the shift, and after a predetermined time has elapsed, the switch is switched to the OFF state. And along with this,
The spool 103a of the timing valve 103 first moves to the right to open the second bypass line 154, and then moves to the left to shut off the second bypass line 154. Therefore, the servo U IJ pressure is quickly discharged through the second bypass line 154 during the first half of the shift operation, and is gradually discharged during the second half through the one-way orifice 82 that performs a throttling action in the discharge direction on the line 126. become. Note that the second bypass line 154 is also provided with a fixed orifice 105, but this orifice 105 is set to have a diameter sufficiently larger than that of the one-way orifice 82.

Here, during this 3-2 downshift, the 3-4 clutch pressure is discharged from the 3-4 clutch 43. In this case, as described above, the third solenoid valve 68 is turned off.
F state, the spool 65 of the 3-4 shift valve 65
Since a is located on the left side, the 3-4' clutch pressure is due to the line 121, the one-way orifice 7 which is not subjected to the throttling action.
6, 2nd drain line 122.3-4 shift valve 65
It passes through the line 124 and is quickly discharged from the drain port 64c of the 2-3 shift valve 64.

Therefore, during this 3-2 downshift, the 3-4 clutch 43 is released early and the engine speed increases quickly, and the opening time of the bypass line 154 that controls the discharge of the servo release pressure and the one-way orifice 8 are
By setting the diameter of 2, it is possible to complete the engagement of the 2-4 brake 45 in time with the engine speed stopping increase, resulting in a fast and smooth gear shift. .

Next, during the 4-2 downshift, the above 3-
Similar to the second shift down, the 3-4 clutch pressure is discharged. However, in this case, the third solenoid valve 6
8 is held in the ON state and the spool 65a of the 3-4 shift valve 65 is held in the right position.
-4 clutch pressure cannot pass through the first drain line 122. Instead, the 3-4 clutch pressure is
One-way orifice 77 by drain line 123
, fixed orifice 78, one-way orifice? 9.3
-4 shift valve 65, and through line 124;
-3 is discharged from the drain port 64c of the shift valve 64, and in this case is subjected to a restricting action by the fixed orifice 78.

However, during this 4-2 downshift, the fifth solenoid valve 104 switches from the OFF state to the ON state when a predetermined time has elapsed from the start of the shift, and the spool 103a of the timing valve 103 shifts from the left side to the right side. The third bypass line 155 is opened. Therefore, during the 4-2 downshift, the 3-4 clutch pressure is quickly discharged through the third bypass line 155 during the first half of the shift operation. Then, in the latter half of the gear shifting operation, the throttle action of the fixed orifice 78 works, and the hydraulic oil is discharged from the 2-3 Akicomulator 80 to the second drain line 123, so that the
-4 The clutch will drop slowly.

By the way, during this 4-2 downshift.

The one-way clutch 51 locks from the idling state, but by cutting off the third bypass line 155 just before that, it is possible to avoid locking the one-way clutch 51 while the oil pressure is stable, and thereby, the speed change operation is performed. Smooth gear shifting can be achieved without increasing time lag.

Regarding this 4-2 downshift, 2-3
The same effect as described above can be obtained by reducing the diameter of the fixed orifice 78 on the second drain line 123 without using the hydraulic pressure holding effect of the accumulator 80.

Also, the servo apply line 120, the servo release line 126, and the 3-4 clutch pressure second drain line 1 are provided with the above orifices 73, 82, and 78, respectively.
23 are unrelated to each other (since they perform gear shifting operations, the diameter of each orifice mentioned above and the operation timing of the timing valve 103 on the bypass line 153, 154, 155 that bypasses these, etc.) This allows you to set it to the optimal state without affecting operation.

Features of the embodiment of the present invention Next, the features of the hydraulic control device according to the embodiment of the present invention will be described in detail.

FIG. 3 shows a hydraulic control circuit 60 similar to that in FIG. 2, but in FIG. ing. Further, FIG. 4 shows an enlarged view of the main part of FIG. 3.

In Fig. 3.4, a coast control valve 83 constituting the switching means of the present invention includes a spool 83a, and the spool 83a is urged rightward in the figure by a coil spring 83b. On the other hand, 2-4 brake 4
5 hydraulic actuator 45' release boat 45
The servo IJ IJ-sline 126 that communicates with b' is branched in the middle to become a line 127,
27 is the port 83 of the coast control valve 83
c and 83d. Note that the port 83c communicates with one end chamber 83e of the spool 83a. Further, the other end chamber 83f of the spool 83a communicates with a line 147 branched from the forward clutch line 116, so that line pressure (forward clutch pressure) is supplied to the other end chamber 83f.

The coast control valve 83 includes a bow) 83.
A port 83g is formed corresponding to port 83d.
g is one-way orifice 84 and ball valve 85
The coast clutch line 128 is connected to the coast clutch 42 via the coast clutch line 128 .

Then, by movement of the spool 83a, the ports 83d and 83g are communicated or disconnected.

That is, when the spool 83a is located on the left side of the drawing, the ports 83d and 83g are in a disconnected state, so that no hydraulic pressure is supplied to the coast clutch 42, and the coast clutch 42 is not engaged. On the other hand, spool 83
When a is located on the right side of the figure (the state shown in Fig. 3.4), the ports 83d and 83g are in communication, and therefore,
Oil pressure is supplied to the coast clutch 42, and the coast clutch 42 is engaged.

Note that the reference numeral 83h indicates a one-way orifice.

The coast control valve 83 is configured as described above, and its operation when shifting from second speed to third speed will be described below. Incidentally, FIG. 5 shows the state at the time of this shift in a table, and please refer to FIG. 5 as well.

First, in the second speed, hydraulic pressure is supplied to the apply port 45a' via the servo apply line 120, and the 2-4 brake 45 is in an engaged state. Further, hydraulic pressure is not supplied to the servo release line 126. Therefore, in the coast control valve 83, hydraulic pressure is not supplied to the chamber 83e at one end of the spool 83a, and the spool 83a is positioned on the left side in the figure due to the line pressure supplied to the chamber 83f at the other end of the spool 83a. do.

Therefore, since the ports 83d and 83g are in a disconnected state, hydraulic pressure is not supplied to the coast clutch 42.
The coast clutch 42 is not engaged.

Thereafter, when a 2-3 shift up is performed, hydraulic pressure is supplied to the release port 45b' via the servo release line 126. Accordingly, in the coast control valve 83, hydraulic pressure is supplied to one end chamber 83e of the spool 83a, and the spool 83 is
a moves to the right against the line pressure in the other end chamber 83f.

Then, when the oil pressure in the servo release line 126 becomes equal to or higher than a predetermined pressure, the 2-4 brake 45 is reliably released. At this time, the hydraulic pressure in the one end chamber 83e and the biasing force of the coil spring 83b overcome the line pressure in the other end chamber 83f, and the spool 83a is located on the right side in the figure.
state in the figure), the port 83d and port 83g communicate with each other. This part, hydraulic pressure, coast control valve 83, one-way orifice 84, ball valve 8
5, and is supplied to the coast clutch 42 via the coast clutch line 128, and the coast clutch 4
2 is concluded.

Therefore, during the 2-3 shift up, the hydraulic pressure for releasing the 2-4 brake 45 exceeds a predetermined pressure, and the 2-4 brake 45 is released.
The coast clutch 42 is engaged after the 2-4 brake 45 is surely released, thus preventing an internal lock in which the coast clutch 42 is engaged before the 2-4 brake 45 is surely released. be able to.

Note that line pressure is introduced into the other end chamber 83f of the spool 83a, so the timing at which the boats 83d and 83g communicate with each other is changed in accordance with the line pressure, and each line pressure In contrast, the correspondence between the communication timing and the pressure level of the release hydraulic pressure can be appropriately set.

"Effects of the Invention" As explained above, according to the present invention, the release chamber of the first friction engagement element and the working chamber of the second friction engagement element include a branch oil passage branched from a common oil passage. is connected, and the branch oil passage on the side of the second frictional engagement element is provided with a switching means that switches to a communication state when the oil pressure to the release chamber of the first frictional engagement element becomes equal to or higher than a predetermined pressure. Then, after the first frictional engagement element is reliably released, the second frictional engagement element is engaged. Therefore, with a simple configuration, internal locking during gear shifting can be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the mechanical configuration of an automatic transmission, FIG. 2 is a circuit diagram of a hydraulic control circuit, and FIG. 3 is a hydraulic control circuit similar to that in FIG. 2, but in accordance with the present invention. A circuit diagram in which members necessary for explaining the features of the example are labeled, FIG. 4 is an enlarged view of the main part of FIG. 3, and FIG. 5 is a 2-
It is a figure which shows the state of the 2-4 brake and coast clutch at the time of a 3rd shift up change. DESCRIPTION OF SYMBOLS 10... Automatic transmission, 30... Speed change gear mechanism, 60... Hydraulic control circuit, 42... Coast clutch, 45... 2-4 brake, 83... Coast control valve, 83a.・・・
Spool, 83b...Coil spring, 83c, 83d, 83g...Boat, 83e.
...One end chamber, 83f...Other end chamber, 126...Servo release line, 127...Line, 128...Coast clutch line, 147...Line.

Claims (1)

[Scope of Claims] A hydraulic control circuit including a speed change gear mechanism, a plurality of friction engagement elements for switching the power transmission path of the speed change gear mechanism, and a plurality of oil passages each communicating with these friction engagement elements. In a hydraulic control device for an automatic transmission configured to change gears by switching the respective oil passages, the plurality of frictional engagement elements include a first frictional engagement element having an engagement chamber and a release chamber; and a second frictional engagement element having a working chamber, wherein the release chamber of the first frictional engagement element and the working chamber of the second frictional engagement element contain branched oil branched from a common oil passage. The branch oil passage on the second friction engagement element side is provided with a switching means that switches to a communication state when the hydraulic pressure to the release chamber of the first friction engagement element reaches a predetermined pressure or higher. A hydraulic control device for an automatic transmission characterized by: