JPS63186055A - Oil pressure circuit of automatic transmission - Google Patents

Abstract

PURPOSE:To prevent generation of two-stage shock, by furnishing the first and the second drain passages to exhaust the operation oil in linking ports, and arranging an orifice at the first drain passage to exhaust the operation oil at an optimum timing at every gear shift operation. CONSTITUTION:The 1-2 shift valve 71 has the first to the fourth ports 711 to 714 as feeding/exhausting converting ports for the operation oil, and also furnishes the first and the second drain ports 715 and 716 to which either a servo applying line 112 or a lorry berth brake line 123 is linked simultaneously by the movement of a spool 71a, while an orifice 71c is furnished at the first drain port 715. When the gear shift 2-3 is operated, the servo applying line 112 is linked to the first drain port 715, but the drainage of the servo applying pressure is performed quietly by the orifice 71c, the connecting force of brakes 2 to 4 is reduced at the beginning of the transmission, and the gear shift to the third position is carried out at a half clutching condition.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a hydraulic circuit for an automatic transmission, in particular, it has an engagement port and a release port, and engages the friction engagement element by supplying and discharging hydraulic oil to both ports. Alternatively, the present invention relates to a hydraulic circuit of an automatic transmission equipped with a hydraulic actuator for releasing the transmission.

(Prior Art) Automatic transmissions generally installed in automobiles combine a torque converter and a speed change gear mechanism, and the power transmission path of this speed change gear mechanism is controlled by selectively operating multiple friction engagement elements such as clutches and brakes. This type of automatic transmission includes a plurality of hydraulic actuators that actuate each of the above-mentioned friction engagement elements, and a hydraulic actuator that operates these actuators. A hydraulic circuit that controls supply and discharge of oil is provided.

By the way, Japanese Patent Application Laid-open No. 55-51153 and Japanese Patent Application Laid-open No. 58
According to Japanese Patent No. 196352 and the like, when a band brake is used as one of the frictional engagement elements, it is shown that a servo piston is used as a hydraulic actuator for actuating the brake. This servo piston has an engagement port and a release port, and releases the band brake when hydraulic oil is not supplied to both ports and when hydraulic oil is supplied to both ports, and releases the band brake when both ports are supplied with hydraulic oil. For example, in an automatic transmission with four forward speeds, hydraulic oil is supplied only to the engagement ports in 2nd and 4th gears. It is used to engage the band brake and release the band brake by not supplying hydraulic oil to both ports in 1st gear, and by supplying hydraulic oil to both ports in 3rd gear.

On the other hand, from a gear position (e.g., 2nd gear) in which the panned brake is engaged by supplying hydraulic oil only to the engagement port of the servo piston, as in the case of 2-3 gear shift in the above example,
When hydraulic oil is also supplied to the release port to release the band brake and engage other frictional engagement elements to shift to the next gear (for example, 3rd gear), the hydraulic oil is supplied to the release port and other operations. Simultaneously with or prior to the start of engagement of the friction engagement element, the hydraulic oil in the engagement port may be temporarily discharged. In this way, the engagement force of the band brake is weakened at the beginning of the shift, resulting in a so-called half-clutch state, and the shift shock during the shift is reduced.

(Problem to be Solved by the Invention) By the way, in the case of the above-mentioned 2-3 gear shift, where hydraulic oil is supplied only to the engagement port of the servo piston, hydraulic oil is also supplied to the release port. When the hydraulic oil in the engagement port is temporarily discharged when shifting to a gear, this discharge operation is performed by operating the shift valve, but if this discharge is too early, the band will be removed before the other friction engagement elements are engaged. The brake is completely released and a neutral state occurs, resulting in a so-called engine revving phenomenon. Therefore, an orifice is provided in the drain passage that is opened by the operation of the shift valve and temporarily discharges the hydraulic oil in the engagement port.

However, if this is done, the following problems occur. In other words, for example, during a 4-1 kickdown shift, hydraulic oil is supplied only to the engagement port of the servo piston and the band brake is engaged, by discharging the hydraulic oil in the engagement port. When shifting to a gear position that releases the band brake, the hydraulic oil in this engagement port is discharged through the drain passage that is temporarily opened during the 2-3 gear shift mentioned above. Since the orifice is provided as described above, the discharge of the hydraulic oil in the fastening port is delayed. Therefore, even after the other frictional engagement elements that were engaged at the previous gear (for example, 4th gear) are released, the band brake remains engaged for a while, and the band brake remains engaged for a while. The gear changes to the target gear (eg, 1st gear) via a gear (for example, 2nd gear), and at this time an unpleasant 2nd gear shock occurs, and the kickdown shift is delayed.

The present invention uses an actuator having an engagement port and a release port like the servo piston described above as one of the hydraulic actuators for operating a friction engagement element, and controls the supply and discharge of hydraulic oil to both ports during gear shifting. In the hydraulic circuit of an automatic transmission, the hydraulic oil is discharged from the engagement port at the optimum timing for each of the two types of gear shifting operations.
The purpose of the present invention is to prevent unpleasant shift shocks, engine revving, etc. during any shift, so that a good shift state can be obtained.

(Means for solving the problem) That is, the hydraulic circuit of the automatic transmission according to the present invention is one of the hydraulic actuators that selectively engages a plurality of frictional engagement elements to obtain a plurality of gears. It has a port and a release port, and when both ports are not supplied with hydraulic oil, and both ports are supplied with hydraulic oil, the locking element is released, and hydraulic oil is supplied only to the engagement port. In a configuration in which an actuator is provided that engages the friction engagement element in a state in which the friction engagement element is engaged in a state in which the friction engagement element is A first drain passage that is temporarily opened when shifting to a gear to which hydraulic oil is supplied to the gear and drains all the hydraulic oil in the engagement port; Both ports are provided with a second drain passage that is opened when shifting to a gear position to which hydraulic oil is not supplied, and discharges the hydraulic oil in the engagement port. The first drain passage is provided with an orifice so that the hydraulic oil is discharged slowly from the fastening port, and the second drain passage is not provided with an orifice so that the hydraulic oil is discharged quickly. Configure it so that

(Function) According to the above configuration, as in the case of 2-3 gear shifting, for example, from a gear stage in which hydraulic oil is supplied only to the engagement port of the hydraulic actuator, to a gear stage in which hydraulic oil is supplied to the release port as well. During gear shifting, when the hydraulic oil in the engagement port is temporarily discharged to bring the vibration engagement element into a half-clutch state in order to reduce shift shock, the hydraulic oil is drained through a first drain passage having an orifice. This prevents the engine from running dry due to premature exhaustion.

Furthermore, when shifting from a gear position where hydraulic oil is supplied only to the engagement port to a gear position where the hydraulic oil from the engagement port is discharged, such as during a 4-1 gear shift, the hydraulic oil does not have an orifice. Since it is quickly drained through the second drain passage, the gear can be shifted directly from, for example, 4th gear to 1st gear, which prevents second gear shock caused by passing through an intermediate gear, and also prevents this shift. This will eliminate the delay.

(Example) Examples of the present invention will be described below.

First, the mechanical structure of the automatic transmission according to this embodiment will be explained with reference to FIG. 1. The automatic transmission 1° includes a torque converter 20 and a
It has a speed change gear mechanism 30 driven by an output of 0, a plurality of friction engagement elements 41 to 46 such as clutches and brakes, and one-way clutches 51 and 52 that change the power transmission path of the mechanism 30. Nori, 2, 1. Each range of H and 1st to 4th speed in D range,
1st to 3rd speeds in 2 ranges 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
The lock-up clutch 26 is provided between the turbine 23 and the turbine 23, and directly connects the engine output shaft "1" and the turbine 23 via the case 21.
3 rotation is outputted to the speed change gear mechanism 30 side 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 drives an oil pump 13 provided at the rear end of the transmission.

On the other hand, the speed change gear mechanism 30 is composed of a Ravigneau-type planetary gear device, and includes a small sun gear 31 with a small diameter loosely fitted on the turbine shaft 27, and a small sun gear 31 that is loosely fitted onto the turbine shaft 27.
1, a large diameter large sun gear 32 loosely fitted on the turbine shaft 27, a plurality of short pinion gears 33 meshed with the small sun gear 31, and a front half meshed with the short pinion gear 33. It is composed of a long pinion gear 34 whose rear half meshes with the large sun gear 32, a carrier 35 that rotatably supports the long pinion gear 34 and the short pinion gear 33, and a ring gear 36 which meshes with the front half of the long pinion gear 34. has been done.

A forward clutch 41 and a first one-way clutch 51 are interposed in series between the turbine shaft 27 and the small sun gear 31, and a coast clutch 42 is interposed in parallel with these clutches 41 and 51. Additionally, a 3-4 clutch 43 is interposed between the turbine shaft 27 and the carrier 35, and a reverse clutch 44 is further interposed between the turbine shaft 27 and the large sun gear 32. Further, a 2-4 brake 45 made of a band brake for fixing the large sun gear 32 is provided between the large sun gear 32 and the reverse clutch 44, and a 2-4 brake 45 is provided between the carrier 35 and the transmission case 11. , a second one-way clutch 52 that receives and receives the reaction force of the carrier 35, and the carrier 35.
A low reverse brake 46 for fixing the is provided in parallel. The ring gear 36 is connected to the output gear 14.
The rotation is transmitted from the output gear 14 to left and right wheels (not shown) via a differential gear.

Next, the frictional engagement elements 41 such as the above-mentioned clutches and brakes
46 and the one-way clutches 51, 52 and the gear positions. First, in the first gear, the forward clutch 41 is engaged and the one-way clutches 51, 52 are engaged. The second one-way clutch 51-52 is in a baroque state. Therefore, the output rotation of the torque converter 20 is input from the turbine shirts 1 to 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 carrier 35 is fixed by the action of the second one-way clutch 52, the planetary gear device 30 performs a differential operation that 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. 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 2nd gear, in addition to the above 1st gear state, 2-
The four-brake 45 is activated, the large sun gear 32 in the planetary gear device 30 is fixed, and the second one-way clutch 52 is idled. 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 meshing with the long pinion gear 34 is fixed. It revolves on the large sun gear 32, and the carrier 35 rotates accordingly. As a result, the rotating bone of the carrier 35 (long pinion gear 3
The rotation of the ring gear 36 is increased by the amount of revolution of 1
A second speed state is obtained in which the reduction ratio is smaller than when the vehicle is at high speed.

Furthermore, in the third speed, the 2-4 brake 45 is released from the second speed state, and the 3-4 clutch 43 is engaged. Therefore, the rotation of the turbine shaft 27' is input to the small sun gear 31 via the forward clutch 41 and the first one-way clutch 51, and at the same time is input to the carrier 35 via the 3-4 clutch 43. Become. As a result, a third speed state is obtained in which the entire planetary gear device 30 rotates integrally and the ring gear 36 rotates at the same speed as the turbine shaft 27.

In addition, in 4th gear, the 2nd gear released in 3rd gear is
-4 Brake 45 is re-engaged. Therefore, the rotation of the turbine shaft 27 is input 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 it is fixed by the -4 brake 45, the long pinion gear 34 rotates while revolving together with the carrier 35. As a result, the long pinion gear 34
The ring gear 36 that meshes with the carrier 35 (rotation of the turbine shaft 27) is rotated at an increased speed by the rotation of the long pinion gear 34, thereby obtaining a fourth speed in an overdrive state. In this case, although the forward clutch 41 is in the engaged state, the first one-way clutch 51 in series with it is idle, so 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 the low reverse brake 46 are engaged, 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 3.0 is fixed. be done. Therefore, the large sun gear 32
Rotation is transmitted through a fixed gear train from 1 to 34 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. If ring gear 3
6 is opposite to the rotation direction of the turbine shaft 27 or large sun gear 32.

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. However, in the 3rd gear of the D range, the 2nd and 3rd gears of the 2nd range, and the 1st and 2nd gears of the lunge, the coast clutch 42 parallel to the first one-way clutch 51 is engaged, and in the first lunge, the coast clutch 42 is engaged. Since the low reverse brake 46 is connected in parallel to the one-way clutch 52, engine braking is obtained in the 3rd gear of the D range, the 2nd and 3rd gears of the 2nd range, and the 1st and 2nd gears of the lunge.

To summarize the relationship between the operation of each of the hydraulic engagement elements 41 to 46 and the one-way clutch 51, 52 and the gear position, the first
As shown in the table.

(Hereinafter, blank spaces) Next, a hydraulic circuit for supplying and discharging hydraulic oil to and from the hydraulic actuators 41a to 46a that operate the frictional engagement elements 41 to 46, respectively, will be described with reference to FIG. Here, among the respective hydraulic actuators 41a to 46a, two
The hydraulic actuator 45a of the -4 brake 45 is composed of a servo piston having an apply port 45a' and a release port 45a'', and it engages the 2-4 brake 45 when hydraulic oil is supplied only to the apply port 45a'. , when both ports 45a' and 45a'' are not supplied with hydraulic oil, and both ports 45a' and 4
5a'' is configured to release the 2-4 brake 45 when hydraulic oil is supplied.Other actuators 41a to 44a and 46a are constituted by ordinary hydraulic pistons, and are configured to release the 2-4 brake 45 when hydraulic oil is supplied. The frictional engagement element is engaged when the friction engagement element is engaged.

This hydraulic circuit 60 first includes a regulator valve 61 that adjusts the pressure of hydraulic oil discharged from the oil pump 13 shown in FIG. 1 to the main line 100 to a predetermined line pressure.
and a throttle valve 62 that generates a throttle pressure according to the accelerator opening of the engine. This throttle pressure is further adjusted by the throttle modulator valve 63 and then supplied to the regulator valve 61, so that the line pressure is set to a value corresponding to the engine accelerator opening. It has become.

The hydraulic circuit 60 also includes a manual valve 64 that selectively sends the line pressure to each hydraulic line according to the selected range, and a manual valve 64 that operates according to the gear position to transfer the line pressure to each of the hydraulic actuators 41a to 41a. 46a are provided with shift valves 71, 72, and 73 of 1-2, 2-3, and 3-4 that selectively supply the fuel to the valve 46a.

The manual valve 64 has an input port f into which line pressure is introduced from the main line 100, and first to fifth output ports a to e, and by movement of the spool 64a,
In the D range, the input port f is the first. The second output ports a and b are connected to the first output port in the 2nd range. Second. The third output ports a, b, and c are connected to the first output port in Lunge. Third. It is connected to fourth output ports a, c, and d, and in the R range, to a fifth output port e. Each of the output ports a to e has first to fifth output lines 101 to 105, respectively.
is connected.

In addition, the above 1-2.2-3.3-4 shift valve 71.
72 and 73 bias the spools 71a, 72a, and 73a to the right side in the drawing with springs, and also have control ports 71b; 72b, 7 on the right side of these spools.
3b is provided. A first control line 106 branched from the main line 1oO is connected to the control port 71b of the 1-2 shift valve 71.
A second output line branched from the first output line 101 is connected to the control ports 72b and 73b of the shift pulp 72 and 73. Third
Control lines 107 and 108 are connected to the control lines 106, 107, and 108, respectively. Second. 3rd solenoid valve 76.77.78
is provided. These solenoid valves 76-7
8 introduces control pressure into the control ports 71b to 73b of the shift valves when they are OFF, and the spools 71
a to 73a are located on the left side in the drawing, and when turned on, the control pressure in the control ports 71b to 73b is drained, and the spools 71a to 73a are located on the right side.

Here, these solenoid valves 76 to 78 receive a signal A from the control circuit 200 to which the vehicle speed of the vehicle and the accelerator opening of the engine are input.

B and C are turned ON according to the gear position to be set.

The solenoid valves 76 to 78 at each gear in the driving range are turned on and off.
The combination pattern of F is set as shown in Table 2.

In particular, in the present invention, when shifting from 2nd speed to 3rd speed in the D range, the intermediate pattern shown in the table is passed through.

(Hereinafter, blank space) On the other hand, the first to fifth output lines 101 to 10 connected to each output port a to e in the manual valve 64
5, main line 1 in each forward range of D, 2.1
The first output line 101 connected to the first output line 101 is led to the actuator 41a of the forward clutch 41 via the one-way orifice 80. Therefore, above, 2
．． During lunge, the forward clutch 41 is always engaged. Note that the first output line 10-1 is provided with an N-D accumulator 81 for buffering when the forward clutch is engaged.

Further, a line 111 is branched from this first output line 101 and led to the 1-2 shift valve 71, and this branch line 111 is connected to the spool 71a when the first solenoid valve 76 is turned on. When it moves to the right, it communicates with the servo apply line 112 through the one-way orifice 82 to the apply port 45a' of the servo piston 45a. Therefore, D.

2. When the first solenoid valve 76 is ON in lunge, that is, 2.3.4 speed in D range, 2nd and 3rd speed in 2nd range,
At the second speed of lunge and lunge, the servo apply pressure is introduced into the apply port 45a'. Furthermore, the servo piston (2-4) is also connected to the servo apply line 112.
A 1-2 accumulator 83 is provided as a buffer when the brake is engaged.

Further, the second output line 102 communicating with the main line 100 in the D and 2 ranges is led to a 2-3 shift valve 72. Is the line 102 spooled when the first solenoid valve is OFF? When 2a is located on the left side, it communicates with the 3-4 clutch line 113 through the one-way orifice 84 to the actuator 43a of the 3-4 clutch 43. Therefore, when the second solenoid valve 77 is OFF in the D and 2 ranges, that is, the 3-4 clutch 43 is engaged in the 3rd and 4th speeds of the D range and the 3rd speed of the 2 range. The 3-4 clutch line 113 is provided with a bypass valve 85 and a 2-3 timing valve 86 in parallel with the one-way orifice 84 to adjust the engagement timing of the 3-4 clutch 43. , the 3-4 clutch line 113
Also provided is a 2-3 accumulator 87 for Mm when the 3-4 clutch is engaged.

Further, a line 114 branched from the 3-4 clutch line 113 and a line 115 branched from the first output line 101 are led to the 3-4 shift valve 73. When the third solenoid valve 78 is OFF and the spool 73a is located on the left side, a line 114 branched from the 3-4 clutch line 113 connects to the release port 45a'' of the servo piston 45a via the one-way orifice 88. release line 116
In addition, line 1 branched from the first output line 101
15 are connected to a coast clutch line 117 that reaches the actuator 42a of the coast clutch 42 via a one-way orifice 89, respectively. Therefore, when both the 2nd and 3rd solenoid valves 77 and 78 are OFF in the D and 2 ranges, that is, in the 3rd speed of the D range and the 3rd speed of the 2nd range, servo release pressure is applied to the release port 45a'' of the servo piston 45a. The 2-4 brake 45 is released, and the third solenoid valve 78 is also
is OFF, that is, 3rd gear in D range, 2nd and 3rd in 2nd range
The coast clutch 42 is engaged in the first and second speeds of speed and lunge.

Here, between the 3-4 clutch line 113 and the line 114 branched from the line 113, the 3-4 clutch pressure and servo release pressure are discharged via branch lines 118 and 119, respectively. Adjust 3
-2 timing valve 90 and 3-2 capacity valve 91 are provided. Further, the coast clutch line 117 is provided with a bypass line 120 that bypasses the one-way orifice 89.
A 3-4 capacity valve 92 is provided for opening and closing. This valve 92 is activated when the 3-4 clutch pressure is generated and when the manual valve 64 is
3rd output line 10 selected for range or lunge
3 is connected to the main line 100, the bypass line 120 is opened to adjust the discharge timing of the coast clutch pressure. Note that the line 121 branched from the third output line 103 is led to the pressure increasing side of the regulator valve 61 via the throttle backup valve 93, so that the line pressure is increased in the second range and lunge.

Further, the fourth output line 104 , which is connected to the main line 100 via the manual valve 64 , is led to the 1-2 shift valve 71 via the low-resolution use valve 94 and the line 122 . And the line 12
2, when the first solenoid valve 76 is OFF, the spool 7
When 1a is located on the left side, one-way orifice 95
The low reverse brake line 123 is connected to the actuator 46a of the low reverse brake 46 via the shuttle valve 96. Therefore, when the first solenoid valve 76 is off during lunge, that is, when the lunge is in first gear, the low reverse brake 46 is engaged.

Further, a fifth output line 105 that communicates with the main line 100 in the R range communicates with the low reverse brake line 123 via the one-way orifice 97 and the shuttle valve 96, and also communicates with the fifth output line 100.
5, a reverse clutch line 124 is connected to the actuator 44a of the reverse clutch 44 via a one-way orifice 98. Therefore, in the R range, the low reverse brake 46 and reverse clutch 44 are always engaged. Furthermore, the reverse clutch line 124 also has an N- line for buffering when the reverse clutch is engaged.
Nine R accumulators are provided. Further, a line 125 branched from the fifth output line 105 is led to the pressure increasing side of the regulator valve 61, and the line pressure is increased in the R range.

In addition to the above configuration, this hydraulic circuit 60 is equipped with a lock-up valve 201 for operating the lock-up clutch 26 in the torque converter 20 shown in FIG. A torque converter line 202 is led from the regulator valve 61 to this valve 201, and a main line 7 line 100 is connected as a control line 203 to a control port 201b at one end.

When the lock-up solenoid valve 204 provided in the control line 203 is turned ON by a signal from the control circuit 200, the control port 201
By draining the control pressure in b and positioning the spool 201a on the right side, the torque converter line 20
2 communicates with a line 205 leading into the torque converter 20, thereby increasing the internal pressure of the torque converter 20 and engaging the lock-up clutch 26. In addition, the solenoid valve 204 is turned OFF and the control port)
By introducing control pressure into 201b, spool 2
When 01a moves to the left, the torque converter line 202 is communicated with the lock-up release line 206, and lock-up release pressure is introduced into the torque converter 20, so that the lock-up clutch 26 is released.

Next, the 1-2, 2-3 shift valves 71 and 72, which are the characteristic parts of the present invention, and the configuration of their surroundings will be explained in detail.

As shown enlarged in FIG. 3, the 1-2 shift valve 71
is a first port 711 to which the first output line 101 from the manual valve 64 (line 111 branched from the first output line 101 in FIG. 2) is connected as a hydraulic oil supply/discharge switching port. , the second port 71 □ to which the servo apply line 112 is connected, the third port 713 to which the line 122 led from the manual valve 64 via the fourth output line 104 and the low-resolution use valve 94 is connected, and the shuttle Fourth port 71 leading to low reverse brake line 123 via valve 96
4, and either the servo brake line 112 or the low reverse brake line 123 is connected simultaneously by movement of the spool 71a.
71s and 71a are provided.

The first drain port 715 has an orifice 71C.
A drain line 130 for 4-1 gear shifting is connected to the second drain port 716.

The 2-3 shift valve 72 also serves as a port for switching the supply and discharge of hydraulic oil.
the first port 721 to which the output line 102 is connected;
-4 clutch line 113 and a second port 722 connected to a branch line 114 that is branched from the line 113 and communicated with the servo release line 116 via the 3-4 shift valve 73; Orifice 72c through which 113 and 114 are communicated
In addition, a port 724 to which the 4-1 shift drain line 130 is connected, and a second drain port 725 having no orifice are provided.

According to the above configuration, the 2-3 shift and the 4-1 shift in the D range, which are the features of the present invention, are performed as follows.

First, to explain the 2-3 gear shift, as shown in FIG. Second solenoid valve 76
．． 77 are both in the ON state, and the spools 71a and 72a of both the shift valves 71 and 72 are located on the right side, so that in the 1-2 shift valve 71, the first output line 101 and the servo apply line 112 are connected. In the 2-13 shift valve 72, the 3-4
The clutch line 113 and its branch line 114 are the first
It communicates with the drain port 723.

Therefore, in this case, only servo apply pressure is supplied to the servo piston 45a, the 2-4 brake 45 is engaged, and the 3-4 clutch 43 is released.

From this state, when the second solenoid valve 77 is turned OFF and the spool 72a of the 2-3 shift valve 72 moves to the left, the second output line 102 communicates with the 3-4 clutch line 113 and the branch line 114, and Since the line 114 is connected to the servo release line 116 through the 3-4 shift valve 73, when the 3-4 clutch 43 is engaged, servo release pressure is also supplied to the servo piston 45a, and the 2-4 brake 45 is activated. To be released. This causes the gear shift to 3rd gear, but at the same time as the second solenoid valve 77 is turned off, the first solenoid valve 76 is also temporarily turned off.
Therefore, as shown in FIG. 3(b), 1-2.
2-3 Spools 71a and 72 of shift valves 71 and 72
A situation arises in which both a are located on the left side. At this time, 1-2
In the shift valve 71, the servo apply line 1
12 communicates with the first drain port 715, the servo apply pressure is drained, and the engagement force of the 2-4 brake 45 is reduced at the beginning of the shift. In this case, the first drain port 715 has an orifice. 71c, the servo apply pressure is slowly drained, thus preventing the occurrence of a neutral state due to the 2-4 brake being completely released before the 3-4 clutch 43 is engaged. Ru. As a result, a shift to 3rd gear is performed while the 2-4 brake 45 is in a moderately half-clutch state.
This makes it possible to effectively reduce gear shift shock while avoiding engine revving. After that, the first solenoid valve 76 is turned ON again and the 1-2
By moving the spool 71a of the shift valve 71 to the right, servo apply pressure is again supplied to the servo piston 45a, completing the shift to the third speed.

In addition, as shown in FIG. 3(b), the 1-2 shift valve 7
When the No. 1 spool 71a moves to the left, the servo apply line 112 communicates with the first drain port 715 and at the same time communicates with the drain line 130 via the second drain port 716. Since the port 724 of the 2-3 shift valve 72 is closed by the spool 72a, the servo apply pressure is drained by the first drain port 71 of the 1-2 shift valve 71 having the orifice 71c.

Next, to explain the 4-1 gear shift, first, in the 4th gear, the first solenoid valve 76 is ON, the second solenoid valve 77 is OFF, and as shown in FIG.
-2.2-3 Spool 71a of shift valve 71.72
, 72a are located on the right and left sides respectively, and in the 1-2 shift valve 71, the first output line 101 and the servo apply line 112 communicate with each other, and in the 2-3 shift valve 72, the second output line 102 and the servo apply line 112 communicate with each other. -4 clutch line 113 and its branch line 114 are in communication. In this case, the branch line 114 and the servo release line 116 are cut off by the 3-4 shift valve 73. Therefore, in this case, the servo piston 45
Only servo apply pressure is supplied to the 2-4 brake 45, and the 3-4 clutch 43 is also engaged.

From this state, when the first solenoid valve 76 is turned OFF and the second solenoid valve 76 is turned ON, as shown in FIG.
), the spool 7 of the 1-2 shift valve 71
1a is to the left, the spool 72 of the 2-3 shift valve 72
a move to the right, and accordingly, in the 1-2 shift valve 71, the servo apply line 112 shifts to the first
．． It communicates with the second drain port 715 and 716, and also the 2-
In the 3-shift valve 72, the 3-4 clutch line 113 and the branch line 114 are connected to the first drain port 723.
It will be communicated to. As a result, the servo apply pressure that was supplied to the servo piston 45a at the 4th speed is drained (the servo release pressure has not been supplied from the beginning), and the 2-4
The brake 45 is released and the 3-4 clutch 43 is also released to shift to first gear.

During this shift, the 2-3 shift valve 72
, the drain line 130 connects to the second drain port 725
The servo apply line 112 is connected to 1-2.
The shift valve 71 communicates with the first drain port 715 having the orifice 71c, and at the same time communicates with the second drain port 725 of the 2-3 shift valve 72, which does not have an orifice, via the drain line 130. Therefore, during this 4-1 shift, the servo apply pressure is quickly drained, and the gear is shifted to 1st speed without passing through an intermediate gear.

In other words, the drain of the servo apply pressure is transferred to the first drain port 7 having the orifice 71c of the 1-2 shift valve 71.
If the servo apply pressure is applied slowly, the 2-4 brake 45 will be engaged after the 3-4 clutch 43 is released, temporarily shifting to 2nd gear, but as mentioned above, if the servo apply pressure is By draining the engine, the gear is directly shifted from 4th gear to 1st gear without going through 2nd gear.

(Effects of the Invention) As described above, according to the present invention, an actuator having an engagement port and a release port is provided as one of the hydraulic actuators for operating a friction engagement element, and hydraulic oil is supplied to these ports during gear shifting. In the configuration in which the supply and discharge control is performed, during the two types of shift operations in which hydraulic oil is discharged from the engagement port, the hydraulic oil is discharged at the optimal timing for each shift operation, so for example 2- When temporarily discharging hydraulic oil from the above-mentioned fastening port to reduce shift shock during 3-speed shifting, this discharge operation is done slowly to avoid the occurrence of a neutral state and prevent the engine from revving. For example, 4-1
When discharging the hydraulic oil from the engagement port during gear shifting, by discharging the hydraulic fluid quickly, the required gear shifting can be performed without going through an intermediate gear.
The occurrence of two-stage shock is prevented. In this way,
All speed change operations will be performed satisfactorily.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a schematic diagram showing the mechanical structure of an automatic transmission, FIG. 2 is a circuit diagram showing a hydraulic circuit, and FIGS. 3(a) and (b) are FIGS. 4(a) and 4(b) are enlarged circuit diagrams showing the operation of the main parts in the hydraulic circuit during the 2-3 gear shift, and FIGS. 4(a) and 4(b) are enlarged circuit diagrams of the main parts showing the operation during the 4-1 gear shift. . 10... automatic transmission, 20... torque converter,
30... Speed change gear mechanism, 41-46... Friction engagement element, 41a-46a... Hydraulic actuator, 45a
'...Apply port, 45a''...Release port, 60...Hydraulic circuit, 71c...
- Orifice, 715... first drain passage (first drain port), 725.130... second drain passage (second drain port, drain line).

Claims (1)

[Claims] (1) A torque converter connected to the engine output shaft, a speed change gear mechanism arranged on the output side of the torque converter, a plurality of friction engagement elements that switch the power transmission path of the speed change gear mechanism, and friction engagement between these elements. A hydraulic circuit for an automatic transmission, comprising a plurality of hydraulic actuators for respectively engaging elements, and configured to obtain a plurality of gears by controlling the supply and discharge of hydraulic oil to these actuators, the hydraulic circuit comprising: One of them is to have a fastening port and a release port, and to release the frictional fastening element in a state in which both ports are not supplied with hydraulic oil and in a state in which both ports are supplied with hydraulic fluid. An actuator is provided that engages the friction engagement element in a state where only hydraulic oil is supplied, and each state of the actuator is configured to be used selectively in a plurality of gear stages, and the engagement port of the actuator is A first drain passage having an orifice that is temporarily opened when shifting from a gear position in which only hydraulic oil is supplied to a gear position in which hydraulic oil is supplied to both ports and discharges the hydraulic oil in the engagement port. and a second drain passage that does not have an orifice and is opened during a gear shift from a gear position in which hydraulic oil is supplied only to the engagement port to a gear gear in which hydraulic oil is not supplied to both ports and discharges the hydraulic oil in the engagement port. A hydraulic circuit for an automatic transmission, comprising: