JPH02113163A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent speed change shock without lengthening speed change time by providing a control means to gradually lock an one-way clutch, at speed change from a first stage to a second stage. CONSTITUTION:At 4 2 shift-down, a by-pass line 155 is opened at the beginning when clutch pressure of a 3-4 clutch 43 starts to release due to OFF condition of a 5th solenoid valve 104, and the clutch pressure is relatively quickly released through a 2-3 shift valve 64 without suffering restrictive action of a fixed orifice 78. Consequently, speed change time at 4 2 shift-down can be shortened. When a turbine rotating speed becomes over the target rotating speed, the solenoid valve 104 becomes ON-condition and the clutch pressure is gradually released, due to the oil pressure maintaining action of an accumulator 80 and the restric tive action of a fixed orifice 78. Therefore, as an one-way clutch gradually changes from a free condition to a lock condition, speed change shock can be prevented.

Description

[Detailed description of the invention] "Industrial application field" The present invention relates to a 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. The system is configured to automatically shift to a predetermined gear position by switching the gear position. Here, the plurality of frictional engagement elements include a reverse clutch, a forward clutch, a coast clutch, and a 3-4 clutch.
There are two clutches, two brakes, a 2-4 brake and a low reverse brake, and two one-way clutches, and the combination of these friction engagement elements and one-way clutches can be changed. This makes it possible to obtain predetermined gears in the drive range (D range), 2 range, lunge, and reverse range (R range).

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 an automatic transmission, for example, when shifting down from 4 to 2, the 3-4 clutch as a friction engagement element switches from the engagement state to the release state due to hydraulic pressure being discharged. In addition, the one-way clutch changes from the free state to the locked state. At this time, if the hydraulic pressure of the 3-4 clutch is quickly discharged, the one-way clutch will suddenly lock, resulting in a shift shock. On the other hand, if the 3-4 clutch is slowly discharged in order to prevent this shift lock, the one-way clutch will gradually lock, so shift shock is prevented, but the shift time becomes longer.

An object of the present invention is to provide a control device for an automatic transmission that can prevent a shift shock when a one-way clutch changes from a free state to a locked state without increasing the shift time.

"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 control device for an automatic transmission, the control device includes a hydraulic control circuit provided in the automatic transmission and is configured to change gears by switching the oil passages, wherein the plurality of frictional engagement elements are configured to shift from a first gear stage to a second gear stage. A one-way clutch is provided in the power transmission path of the transmission gear mechanism, and includes a friction engagement element that discharges hydraulic pressure when shifting to a gear, and the one-way clutch moves from the first gear to the second gear. It is configured to change from a free state to a locked state when shifting to a gear, and at the initial stage when shifting from the first gear to the second gear, the oil pressure of the friction engagement element is controlled. The present invention is characterized in that a control means is provided for quickly discharging the hydraulic pressure of the frictional engagement element and then slowly discharging the hydraulic pressure of the frictional engagement element from before the locking of the one-way clutch.

"Function" In the present invention, when shifting from the first gear to the second gear, the control means quickly discharges the hydraulic pressure of the friction engagement element at the beginning, but then the one-way clutch is activated. The hydraulic pressure of the frictional engagement element is gradually discharged before locking, so that the one-way clutch gradually locks.

"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, which allow driving ranges D and 2 to be changed.
．． 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 14, 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 the first gear, the forward clutch 41 is engaged, and the first and second one-way clutches 51 and 52 are engaged.
becomes locked. For this reason, the torque converter 20
The output rotation is input from the turbine shaft 27 to the small sun gear 31 of the planetary gear device 30 via the forward clutch 41 and the first one-way clutch 51. In this case, since the gear 35 is fixed by the action of the second one-way clutch 520, the planetary gear device 30 transmits 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 without differential operation.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, in second speed, the forward clutch 41 is engaged, the first one-way clutch 51 is in a locked state, the 2-4 brake 45 is engaged, and the large sun gear 32 in the planetary gear device 30 is fixed. The second 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 long pinion gear 34 via the short pinion gear 33, and the large sun gear 32 that meshes with the long pinion gear 34 is fixed. Therefore, it revolves on the large sun gear 32, and the carrier 35 rotates accordingly. As a result, the rotation of the ring gear 3B 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.

Furthermore, when shifting to third gear, the 2-4 brake 45 is released from the second gear state and at the same time, the 3-4 clutch 43 is engaged. Therefore, the rotation of the coupling 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
The carrier 35 will also be powered via the 3-4 clutch 43. As a result, the entire planetary gear device 3o rotates integrally, and the ring gear 36 rotates around the turbine shaft 2.
A three-speed collar rotating at the same speed as 7 is obtained.

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 input to the carrier 35 of the planetary gear device 30 through the 3-4 clutch 43, 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 rotational speed of the four rotational bones will be increased and the rotation speed will be increased, thereby obtaining a four-speed overdrive state. In this case, the forward clutch 41 is in the engaged state, but the first one-way clutch 5 in series with the forward clutch 41 is in the engaged state.
1 is in an idling state, and the coast clutch 42 is not engaged, so 270 rotations of the turbine shaft are not input to the small sun gear 31.

Further, in reverse speed, the reverse clutch 44 and the low reverse brake 46 are engaged, so that the rotation of the turbine shaft 27 is manually applied 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 the 3rd speed and the 1st and 2nd speeds of the I range, the coast clutch 42 parallel to the first one-way clutch 51 is engaged.
Further, in the first gear of the lunge, the low reverse brake 46 is engaged in parallel with the second one-way clutch 52, so that 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 bow 45a' and a release port 45b'. And apply po) 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 ports and both ports) 45
When hydraulic pressure is supplied to both a'45b', 2-4
Brake 45 is adapted to be released.

Further, 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 hull pro 2 has a manual port e into which line pressure is introduced from the main line 110, and first to fourth output capos a to d. However, in D range and 2 range, the first
, the second output port a1b for the lunge, the first and third output ports a and C for the lunge, and the fourth output port d for the R range. 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 63a, 64a, 6, respectively.
5a is biased toward the right side in the drawing by a spring (not shown), and these spools 63a, 64a,
On the right side of 65a, pilot ports 63b, 64b,
65b is provided. The main line 11 is connected to the pilot port 63b of the 1-2 shift valve 63.
The first pilot line 115 led from the first output line 111 is connected to the pilot port 64b, 65b of the 2-3.3-4 shift valve 64.65, and branched from the first output line 111 via the line 116, respectively. The second and third pilot lines 117.118 are connected respectively, and these pilot lines 115.117.1
18 are provided with a second solenoid valve 66, a second solenoid valve, and a third solenoid valve 66, 68, respectively. When each of these solenoid valves 66 to 68 is in the ON state,
By draining the pilot lines 115, 117, and 118 to discharge the pilot pressure in the pilot ports 63b-65b of each corresponding shift valve 63-65, the spools 63a-6:a are moved to the N side in the drawing. to be located. On the other hand, when the solenoid valves 66 to 68 are in the OFF state, the pilot boats 63b to 65
Pilot pressure is introduced from each pilot line 115, 117, 118 to spools 63a to 65a, respectively, to position them 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, the relationship between each gear stage and the combination pattern of the ○N10FF state of each solenoid valve 66 to 68 is set as shown in Table 2. In addition, at the time of a 3-shift downshift, the shift is made via the intermediate notch shown in the table.

Next, each output capo in the above manual Harupro 2)
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 via a line 119 to an ND engine generator 72 for buffering when the forward clutch is engaged.

Further, the first output line 111 is connected to the 1-2 shift valve 6
3, and when the first solenoid/SL valve 6 is turned on and the spool 63a is located on the right side, the first output line 111 communicates with the servo apply line 120 and connects the one-way orifice 73. Through,
Apply port of servo piston 45') 45 a'
leading to. Therefore, when the first solenoid valve 66 is in the ON state in D%2 range, that is, in D range 2.
In 3.4 speed, 2.3 speed of 2 range, and 2nd speed of lunge, hydraulic pressure (servo apply pressure) is introduced to apply bow) 45a', and at this time, the release port 45b'
If oil pressure (servo IJ IJ-s pressure) is not introduced into the brake, the 2-4 brake 45 will be engaged. Incidentally, a 12-12 accumulator 74 is connected to the servo apply line 120 for use as a buffer 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 12 range, that is, 3.4 speed in the D range and 3 in the 2 range.
At high speed, the 3-4 clutch 43 will be engaged.

Here, from the 3-4 clutch line 121, 11.1
Two drain lines 122 and 123 are branched, and among these, the first drain line 122 is led to the 34/ft valve 65, and when the third solenoid HALPRO 8 is in the OFF state (the spool 65a is on the left side), the first drain line 122 is connected to the line 124. It communicates with the drain port of the 2-3 shift valve 64. In addition, the ζ second drain line 123 includes a one-way orifice 77, a fixed orifice 78, and a one-way orifice 7.
9 to the same <, 3-47 foot valve 65, and the third solenoid valve 68 is in the ON state (spool 65
a is on the right side), it connects to line 124, and 2-3
It leads to the drain port of the 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 switched to ○N.
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 led 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, when the second and third solenoid valves 67 and 68 are both OFF in the D and 2 ranges, that is, in the 3rd gear of the D range and the 3rd gear 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, one hydraulic pressure is introduced into the servo release line 126 in the third gear of the D range and the third gear in the second range.
The coast clutch 42 is engaged at a high speed.

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 line 131 via 2-3 shift hull pro 4. This line 131 further communicates with the coast clutch 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, at 2nd speed in the 2nd range and 1.2nd speed in the 1st range.

The third output line 113, which is connected to the main line 110 through 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 soft 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 46 via the low reverse brake line 133 . Therefore, when the first solenoid valve 66 is in the OFF state in the L range, that is, in the first speed of the L range, 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 scratch 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 amplifier 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 line 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 amplifier 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 a lock-up release line 139 via a lock amplifier control pulp 92', so that lock-up release pressure is introduced into the torque converter 20 and the lock-up clutch 26 is released.

The hydraulic control circuit 60 also includes a line pressure control valve adjusted by a regulator valve 61, a throttle modulator valve 95, a duty solenoid valve 96 for operating the valve, and a cut bank valve 97. ing.

A line 140 branched from a line 137 leading to the main line 110 is led to the throttle modulator valve 95 via a lenoid reducing valve 93, and a line 140 is connected to the throttle modulator valve 95 by a duty lenoid valve 96 that opens and closes periodically. Adjusted pilot pressure is introduced into one end of the spool 95a, and this duty
Throttle module pressure is generated in accordance with the duty rate of the solenoid valve 96 (ratio of valve opening time during one cycle). 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 increase port 61a of the regulator valve 61 through the line 141. , 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. The pilot pressure generated when the first solenoid valve 66 is in the OFF state is introduced into the first port 97b via the line 143, and the second solenoid valve 67 is introduced into the second port 92c. The pilot pressure generated when the third solenoid valve 68 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. Pressure 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 6G 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 and 68 are in the OFF state), the in 142 is shut off, and pilot pressure is introduced only to the third port 97d. The line 142 is cut off at the 2nd speed of the 2nd range (with only the third solenoid valve 68 in the OFF state) and the 2nd speed of the lunge. On the other hand, at gears other than these, the line 142 is connected to the line 146, and the throttle modulator pressure is introduced into the pressure reducing boat 61b of the regulator valve 61, thereby reducing the line pressure. There is.

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.

Coast control valve 83 C, as mentioned above,
Line pressure (forward clutch pressure) is provided on a line 127 branched from the servo release line 126 and connected to the coast clutch line 128 via the ball valve 85, and also by a line 147 branched off from the forward clutch line 116. Spool 83a
being led to the other end. 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 fan 147, the line 127 It is now possible to communicate.

Therefore, through this line 127, the coast clutch 4
In D range where coast clutch pressure is supplied to 2 and 2-3 upshift in 2 range, servo I
After the J IJ-space pressure has risen sufficiently, that is, 2-4
After the brake 45 is reliably released, the coast clutch 42 is engaged. Therefore, internal locking caused by the 2-4 brake 45 and the coast clutch 42 being engaged simultaneously is prevented. In addition, since the line pressure is led to one end of the spool 83a, the timing at which the line 127 is communicated is changed in accordance with the line pressure, and the communication timing and the servo IJ-S pressure are changed. The correspondence relationship with the pressure level can be set appropriately.

Further, the bypass valve 101 is provided on a bypass line 148 that bypasses the one-way orifice 76 provided in the 3-4 clutch line 121. 3-
The hydraulic pressure (3-4 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 hydraulic 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.
7) Line 14 led from modulator valve 95
Modulator pressure via 9 and 150 is introduced to the other end of the spool 101a of the bypass valve 101. When the 3-4 clutch pressure rises above a predetermined value and the spool 101a moves to the left, the bypass line 148 is cut off.

Therefore, the 3-4 clutch pressure is quickly supplied by the bypass line 148 at the beginning of supply, but thereafter the supply is slowed by the one-way orifice 76.
In this way, the 3
-4 The engagement timing of the clutch 43 is adjusted.

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 hydraulic pressure supply direction on the IJ-sline 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 above-mentioned flo nottor modulator pressure is introduced into the center of the spool 102a via the line 149 and line 152, and further, spool! 02a
The servo release pressure downstream of the bypass line 151 is introduced into the other end.

Then, the bypass line 151 is opened or closed by the action of the 3-4 clutch pressure, throttle modulator pressure, and servo release pressure, and the servo IJIJ-stress pressure is adjusted in response to the increase in the 3-4 clutch pressure. It's designed to put pressure on you.

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 the one-way orifice 79).

The main line 1 is attached to one end of the spool 103a.
A pilot line 157 led from 10 through a line 156 is connected thereto, and a fifth solenoid valve 104 is provided on the line 157.

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 soft up-shifting, the first solenoid valve 66 is switched from the OFF state to the ON state, so that the spool 63a of the 1-2 shift valve 63 moves 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 port 45a' of the servo piston 45' via the one-way orifice 73, and thereby the 2-4 brake 45 will be concluded.

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.

For this reason, the spool 103a of the timing valve 103
moves to the right side, and the first bypass line 153 that bypasses the one-way orifice 73 is brought into communication. Therefore, in the first half of the shift operation, the servo apply pressure is quickly supplied to the apply boat 45a'.

Then, when a predetermined period of time has elapsed from the start of the shift during gear shifting, 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 to move the spool 103a of the timing valve 103 to the left.
Bypass line 153 is shut off. Therefore, in the latter half of the shift operation, the servo apply pressure is slowly supplied to the apply bow 45a' of the servo piston 45' via the one-way orifice 73.

In this way, during the ■-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 in the ON state, the third valve and the 'id valve 68 are in the O state.
It becomes FF 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 port 45b' of the servo piston 45' is applied to the line 126, the one-way orifice 82.81.3-4 shift valve 65,
Via line 125 and one-way orifice 75,
It will be discharged from the drain boat 64c of the 2-3 shift valve 64.

During this shift, the fifth solenoid valve 104
As in the case of the 1-2 upshift, the switch is first switched from the OFF state to the ON state at the start of the shift, and then switched to the OFF state after a predetermined period of time has elapsed. 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 IJ pressure is quickly discharged through the second bypass line 154 during the first half of the speed change 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 the 3-2 downshift, the 3-4 clutch pressure is discharged from the 3-4 clutch 43. In this case, as mentioned above, the third solenoid valve 6.8 is
It is in the FF state, and the spool 6 of the 3-4 shift valve 65
Since 5a is located on the left side, the 3-4 clutch pressure is on line 1211. One-way orifice 76 not subject to throttling, second drain line 1.22.3-4 shift valve 65 and line 124 to 2-3 shift valve 6
It will be quickly discharged from the drain boat 64c of No. 4.

Therefore, during this 3-2 downshift, the 34 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 82 are
By setting the diameter of , it is possible to complete the engagement of the 2-4 brake 45 in time with the timing when the engine speed stops increasing, and a fast and smooth gear shift can be realized.

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 N 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 79.3
-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 throttling 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 shift operation, the throttle action of the fixed orifice 78 works, and the hydraulic oil is discharged from the 2-3 accumulator 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 is locked from the idling state, but by cutting off the third bypass line 155 just before that, the one-way clutch 51 is locked in a state where the oil pressure is stable. As a result, smooth gear shifting can be achieved without increasing the time roughness of gear shifting operations.

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 Akimuray 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 performs a speed change operation independently of each other, so the diameter of each orifice and the operation timing of the timing valve 103 on the bypass line 153, 154, 155 that bypasses these, etc. It is possible to set it to the optimum condition without affecting the system.

Hydraulic control circuit according to an embodiment of the present invention Next, a hydraulic control circuit according to an embodiment of the present invention will be described in detail.

FIG. 3 shows a hydraulic control circuit 60 similar to that shown in FIG. 2, but in FIG. 3, reference numerals are attached to members necessary for a detailed explanation of the present invention. Further, FIG. 4 shows an enlarged view of the main part of FIG. 3.

In Figure 3.4, line 12 of 3-4 crunch 43
1 is branched into two lines, one line 121.122
is connected to the 3-4 shift valve 65 through the one-way orifice 76, and the other line 123 is connected to the 3-4 shift valve 65 through the one-way orifice 77.
4 shift valve 65. Here, 3-4
The shift valve 65 is operated by the third solenoid HALPRO 8, and when the third solenoid valve 68 is in the OFF state, the 3-4 shift valve 65 is operated by the line 121.
122 is communicated with the line 124, and conversely, when the third solenoid valve 68 is in the ON state, the 3-4 shift valve 65 communicates the line 123 with the line 124. Note that the line 124 is communicated with a drain via a 2-3 shift valve 64.

In the above configuration, when shifting down from 3 to 2,
Since the third solenoid valve 68 is in the OFF state during the gear shift, the 3-1 shift valve 65 is in the OFF state during the shift.
1.122 to communicate with line 124. This results in
The oil pressure of the 3-4 crunch 43 is controlled by a line 121, a one-way orifice 76 that is not subject to throttling action, and a line 122.
3-4 shift valve 65, through line 124, 2-
3) is discharged from the drain port 64C of the valve 64. In this case, the hydraulic pressure is not subject to throttling action, so
Hydraulic pressure will be discharged quickly, reducing shift time. Note that during the 3->2 soft down shift, the one-way clutch 51 remains locked, so the 3-4
Even if the hydraulic pressure of the clutch 43 is quickly discharged, the one-way clutch 51 is not affected.

On the other hand, during the 4→2 soft down shift, the third solenoid HALPRO 8 is in the ON state, so the 3-4/but valve 65 connects the line 123 with the line 124.

As a result, the hydraulic pressure of the 3-4 clutch 113 passes through the line 121, one-way orifice 77, line 123, fixed orifice 78, one-way orifice 79, line 123. drain port) 64C. In this case, since a 2-3 accumulator 80 is provided in the line 123 between the one-way orifice 77 and the fixed orifice 78, the hydraulic pressure holding action of the accumulator 80 and the accumulator 8
Due to the throttling action of the fixed orifice 78 downstream of 0, the hydraulic pressure is slowly discharged.

Therefore, during a 4→2 downshift, the hydraulic pressure of the 34 clutch 43 is slowly discharged, so the one-way clutch 51 gradually changes from a free state to a locked state, and therefore, shift shock can be prevented. .

Furthermore, in the configuration of FIG. 3.4, the fixed orifice 7
8 and one-way orifice 79 is provided, and the third bypass line 155 is provided to bypass the one-way orifice 79.
5 is provided with a timing valve 103, and this timing valve 103 is operated by a fifth solenoid valve 104. That is, when the fifth solenoid valve 104 is in the ON state, the timing valve 103
When the fifth solenoid valve 104 is in the OFF state, the timing valve 103 is in the communication state and communicates the bypass line 155.

In the above configuration, the operation at the time of 4→2 downshift will be explained with reference to the flowcharts of FIG. 3.4 and FIG. 5, and FIG. 6.

The process starts in step 200, and in step 202, the accelerator opening degree X1 speed V1 flag S is read.

Here, the flag S is 1 at the time of 4→2 downshift.
and is 0 in other states.

If flag S is not 1 in step 204, step 20
Returning to step 2, if flag S is 1, step 20
Proceed to step 6.

Steps 204→206 correspond to time 1° in FIG. 5, the second solenoid valve 67 is in the ON state p, and 3-
The clutch pressure of the 4-clutch 43 begins to be discharged.

At this time, the fifth solenoid valve 104 is in the OFF state, so the timing valve 103 is in communication and the bypass line 155 is in communication. Therefore, 3-
The hydraulic pressure of the 4 clutches 43 is from the line 121, the one-way orifice 77, the line 123, the bypass line 155,
It passes through the timing valve 103, the bypass line 155, the line 123.3-4 shift valve 65, and the line 124, and is discharged from the drain port 64C of the 2-3 shift valve 64. In this case, the discharged hydraulic pressure bypasses the fixed orifice 78 and is drained, and is subjected to the hydraulic pressure holding action of the accumulator 80, but is not subjected to the throttling action of the fixed orifice 78, and the hydraulic pressure is drained relatively quickly. It is discharged. Therefore, it is possible to shorten the shift time when shifting down from 4 to 2. Note that the state in which the oil pressure is discharged relatively quickly is clearly shown at times t1 to t2 in the timing chart of FIG.

In step 208, the first
A target turbine rotation speed Nxl and a second target turbine rotation speed NK2 are determined. Here, NX1, N, □ are
Since it is a function of vehicle speed V, N.

f(v), Niz=g(V), and for example,
NX1=N)12X is set to 80%.

In step 210, the actual turbine rotation speed N is determined, and in step 212, it is determined whether the actual turbine rotation speed N7≧first target turbine rotation speed N8, and if NT≧NX, Proceeding to step 214, the fifth solenoid valve 104 is turned on.

Steps 212→214 correspond to time t2 in FIG. 5, and the fifth solenoid valve 104 is turned on.

Therefore, since the timing valve 103 is in the cutoff state, the bypass line 155 is cut off. Therefore, 3
-4 The hydraulic pressure of the clutch 43 is the line 121, the one-way orifice 77, the line 123, the fixed orifice 78,
It passes through the one-way orifice 79, the line 123, the 3-4 shift pal flow 5, and the line 124, and is discharged from the drain port 64C of the 2-3 shift valve 64. In this case, the discharged hydraulic pressure is gradually discharged due to the hydraulic pressure holding action of the accumulator 80 and the throttling action of the fixed orifice 78. Therefore, during the 4->2-shift downshift, the one-way clutch 51 gradually changes from the free state to the locked state, so that shift shock can be prevented. In addition, regarding the state in which the oil pressure is gradually discharged, from time t2 in the timing chart of FIG.
This is clearly shown at t3.

In step 216, the actual turbine rotation speed NT is determined, and in step 218, it is determined whether the actual turbine rotation speed N7≧the second target turbine rotation speed N, I□, and if N, ≧NX2. , the process proceeds to step 220, and the fifth solenoid valve 104 is turned off. Thereafter, the process advances to step 222 and returns.

Note that step 220 corresponds to time t3 in FIG.

"Effects of the Invention" As explained above, according to the present invention, when shifting from the first gear to the second gear, the hydraulic pressure of the friction engagement element is quickly discharged at the initial stage, and then the one-way clutch Since a control means is provided to slowly discharge the hydraulic pressure of the frictional engagement element from before the locking, when shifting from the first gear to the second gear, the hydraulic pressure of the frictional engagement element is quickly discharged at the beginning of the shift from the first gear to the second gear. After that, the hydraulic pressure of the friction engagement element is gradually discharged from before the one-way clutch is locked, so that the one-way clutch is gradually locked. Therefore, shift shock when the one-way clutch changes from the free state to the locked state can be prevented without increasing the shift time.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the mechanical configuration of the automatic transmission, Fig. 2 is a circuit diagram of a hydraulic control circuit, and Fig. 3 is a hydraulic control circuit similar to Fig. 2, but details of the present invention are shown. 4 is a circuit diagram in which members necessary for explanation are labeled with reference numerals; FIG. 4 is a configuration diagram schematically showing the necessary members of FIG. 3;
and Fig. 5.6 are a timing chart and a flowchart, respectively, during a 4->2 downshift. lO... Automatic transmission, 30... Speed change gear mechanism, 60... Hydraulic control circuit, 43... 3-4 clutch, 64... 2-3 shift valve, 64C... ...Drain boat, 65...3-4 shift valve, 67...Second solenoid valve, 68...Third solenoid valve, 76...One-way orifice, 77... One-way orifice, 78... Fixed orifice, 79... One-way orifice, 80... 2-3 accumulator, 03... Timing valve, 04... Fifth solenoid valve, 21... ... line, 23 ... line, 24 ... line, 55 ... bypass line. Figure 4 Figure 5 zb

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 control device for an automatic transmission configured to change gears by switching the respective oil passages, the plurality of friction engagement elements are configured to change gears when shifting from a first gear to a second gear. A one-way clutch is provided in the power transmission path of the transmission gear mechanism, and includes a friction engagement element from which hydraulic pressure is discharged, and the one-way clutch is used when shifting from the first gear to the second gear. The gear is configured to change from a free state to a locked state, and when shifting from the first gear to the second gear, the hydraulic pressure of the friction engagement element is quickly discharged at the initial stage, and then the one-way A control device for an automatic transmission, characterized in that a control device is provided for slowly discharging the hydraulic pressure of the frictional engagement element from before the clutch is locked.