JPH04107358A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE:To perform reliable control of lowering of an engaging pressure according to a kind of a shift through extremely simple constitution by providing a control means to control operation of a timing valve according to a kind of a shift during a shift wherein the engaging pressure of a specified friction engaging element is lowered. CONSTITUTION:A hydraulic control circuit is provided with a bypass circuit 143 to feed an oil pressure to a 2-4 brake 45 in a way to bypass an orifice 74 for an accumulator located in an oil passage running to a frictional engaging element, for example, a 2-4 brake 45, and a timing valve 203 to control an oil pressure feed and discharge timing through the bypass circuit 143. A control means 47 to control operation of a timing valve 103 according to a kind of a shift during a shift wherein the engaging pressure of the 2-4 brake 45 is lowered is provided. This constitution facilitates control of lowering of an engaging pressure according to a kind of a shift through extremely simple constitution where the single timing valve 103 is employed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for an automatic transmission, and more particularly to a variable speed control device for reducing the engagement pressure of a specific friction engagement element (for example, 2-4 brake). This invention relates to a control device for an automatic transmission that is applied when carrying out the following.

(Prior Art) Generally, automatic transmissions installed in automobiles combine a torque converter and a speed change gear mechanism, and selectively actuate a plurality of friction engagement elements such as clutches and brakes to control the power transmission path of the speed change gear mechanism. The system is configured to automatically shift to a predetermined gear position by switching to a predetermined gear position.

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. Specifically, this hydraulic control circuit includes a regicolator valve that adjusts the discharge pressure of the oil pump to a predetermined line pressure, a manual valve that switches the range by manual operation, and a manual valve that operates according to the operating state to control each of the above-mentioned actuators. By switching the oil path leading to
It is composed of a plurality of shift valves that selectively operate a plurality of frictional engagement elements and various valves that perform other auxiliary functions.In recent years, in particular, by driving the shift valves with solenoid valves, Attempts have been made to adapt gear shift control to driving conditions and to perform it with higher precision.

By the way, in this type of automatic transmission, when performing a gear change that reduces the engagement pressure of a specific friction engagement element (for example, 2-4 brake), it is necessary to vary the manner in which the engagement pressure is reduced depending on the type of shift. Therefore, there is a hydraulic pressure for engaging the frictional engagement element (i.e., engagement pressure), and an oil pressure for releasing the frictional engagement pressure element (ie, release pressure).
Conventionally, a method of controlling the timing valves using separate timing valves has been used (e.g.
(See Publication No. 6055).

(Problems to be Solved by the Invention) In the case of the above-mentioned known example, since two timing valves are required, the circuit configuration of the hydraulic circuit is of course complicated.
There is a problem in that the control of timing valves and the like must also be complicated.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to reliably control the reduction in engagement pressure according to the type of speed change with an extremely simple configuration.

(Means for Solving the Problem) In the invention of claim 1, as a means for solving the above problem, there is provided a speed change gear mechanism, a plurality of frictional engagement elements for switching the power transmission path of the speed change gear mechanism, and a plurality of friction engagement elements for switching the power transmission path of the speed change gear mechanism. and a hydraulic control circuit that controls the supply and discharge of working hydraulic pressure to and from the hydraulic actuator of the friction engagement element, and is set to switch the engagement state of a plurality of specific friction engagement elements among the friction engagement elements during a predetermined speed change. In the control device for an automatic transmission, the hydraulic control circuit supplies and discharges hydraulic pressure to the specific friction engagement element by bypassing an accumulator orifice provided in an oil path leading to the specific friction engagement element. A bypass circuit and a timing valve for controlling hydraulic pressure supply/exhaust timing via the bypass circuit are provided, and at the time of a shift in which the engagement pressure of the specific friction engagement element is decreased, depending on the type of shift. A control means for controlling opening and closing of the timing valve is attached.

In a second aspect of the invention, as a means for solving the above problem, in the automatic transmission control device according to the first aspect, the specific friction engagement element is connected to a brake having an apply chamber and a release chamber. and the control means,
When the servo apply pressure of the brake is temporarily removed during a shift, the timing valve is closed, and when the servo apply pressure of the brake is completely removed, the timing valve is opened. There is.

(Function) In the inventions of claims 1 and 2, the following effects can be obtained by the above means.

That is, during a shift to reduce the engagement pressure of a specific friction engagement element (for example, during a shift to release a 2-4 brake equipped with an apply chamber and a release chamber), the orifice for the Akicomulator is controlled by opening/closing the timing valve. Discharging hydraulic pressure from the friction engagement element (e.g., servo apply pressure for the 2-4 brake) through a bypass circuit that bypasses the flow, or discharging hydraulic pressure from the friction engagement element (for example, the servo apply pressure for the 2-4 brake) through an accumulator orifice. The discharge of the servo apply pressure of the 2-4 brake is selected depending on the type of shift (for example, a shift that temporarily removes the servo apply pressure of the 2-4 brake or a shift that completely removes the servo apply pressure).

(Effects of the Invention) According to the inventions of claims 1 and 2, the transmission gear mechanism, the plurality of friction engagement elements for switching the power transmission path of the transmission gear mechanism, and the hydraulic pressure applied to the hydraulic actuators of these friction engagement elements are provided. A control device for an automatic transmission, which has a hydraulic control circuit for controlling supply and discharge, and is set to switch engagement states of a plurality of specific friction engagement elements among the friction engagement elements during a predetermined gear shift. In the hydraulic control circuit, a specific friction engagement element (for example, an apply chamber and a release chamber) is connected to a specific friction engagement element (for example, an apply chamber and a release chamber) by bypassing an orifice for an Akicomulator provided in an oil passage leading to a specific friction engagement element (for example, 2-4 brake). In addition to providing a bypass circuit for supplying and discharging hydraulic pressure to the 2-4 brake equipped with a brake, and a timing valve that controls the timing of supplying and discharging hydraulic pressure via the bypass circuit, a decrease in the engagement pressure of the specific friction engagement element is prevented. When changing speeds, the type of speed change (for example, 2-4
Since a control means is attached to control the opening and closing of the timing valve according to a shift in which the servo apply pressure of the brake gear is temporarily removed during a shift or a shift in which the servo apply pressure is completely removed, it is possible to control the opening and closing of the timing valve in response to a shift in which the engagement pressure of a specific friction engagement element is reduced (e.g. , during gear shifting to release the 2-4 brake), by controlling the opening and closing of the timing valve, the hydraulic pressure from the friction engagement element (for example, the servo apply pressure of the 2-4 brake) is transferred via a bypass circuit that bypasses the accumulator orifice. ) or the discharge of hydraulic pressure (e.g., servo apply pressure for 2-4 brakes) from the friction engagement element via the accumulator orifice for the type of speed change (e.g., servo apply pressure for 2-4 brakes temporarily during the process). With an extremely simple configuration using one timing valve, the engagement pressure reduction can be easily controlled depending on the type of speed change. It has the excellent effect of being able to

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

First, the mechanical structure of the automatic transmission according to this embodiment will be explained with reference to FIG.

The automatic transmission 10 of this embodiment has the following main components:
A torque converter 20, a speed change gear mechanism 30 driven by the output of the torque converter 20, a plurality of frictional engagement elements 41 to 46 such as clutches and brakes that switch the power transmission path of the speed change gear mechanism 30, and a one-way clutch 5152. 2,1. Each of the R ranges, 1st to 4th speeds in the D range, 1st to 3rd speeds in the 2nd range, and 1st to 2nd speeds in the L range are available.

The torque converter 20 includes a pump 22 fixedly installed in a case 21 connected to the engine output shaft 1, a turbine 23 arranged opposite to the pump 22, and driven by the pump 22 via hydraulic oil. a stator 25 that is interposed between the turbine 23 and the pump 22 and supported by the transmission case 11 via the one-way clutch 24 to increase torque; and the case 21 and the turbine 23.
The lock-up clutch 26 is provided between the engine and the turbine 23 and directly connects the engine output shaft l 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 soyaft 27. Here, a pump shaft 12 passing through a turbine shaft 27 is connected to the engine output shaft l, and the pump shaft 12 drives an oil pump 13 provided at the rear end of the automatic transmission 10. It has become.

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 2, and a turbine shaft 27 behind the small sun gear 31.
A large sun gear 32 with a large diameter is loosely fitted thereon, a plurality of short pinion gears 33 are meshed with the small sun gear 31, the front half of which is meshed with the short pinion gear 33, and the rear half of which is meshed with the large sun gear 33. 32, a carrier 35 that rotatably supports the long pinion gear 34 and the short pinion gear 33, and the long pinion gear 34.
The ring gear 36 is meshed with the front half of the ring gear 36.

A forward clutch 41 and a first one-way clutch 51 are interposed in series between the turbine shaft 27 and the small Zangya 31, and a coast clutch 42 is connected in parallel to these clutches 41 and 51. Intervention is provided. Further, a 3-4 clutch 43 is interposed between the turbine shaft 27 and the carrier 35, and a reverse clutch 44 is interposed between the turbine shaft 27 and the large sun gear 32.

Further, the large sun gear 32 and the reverse clutch 4
A 2-4 brake 45 serving as a band brake for fixing the large sun gear 32 is provided between the carrier 35 and the transmission case 11. 2nd one-way clutch 5 that stops U
2, and a low reverse brake 4 that fixes the carrier 35.
6 are provided in parallel. The ring gear 36 is connected to the output gear 14, and rotation is transmitted from the output gear 14 to left and right wheels (not shown) via a differential device.

Frictional engagement elements 41 to 46 such as the clutches and brakes
Since the relationship between the operating state of the one-way clutch 5152 and the gear position is well known, a detailed explanation thereof will be omitted and will be shown in Table 1. In Table 1, the ○ mark indicates the engaged state, and the * column indicates coasting time slip. (Hereinafter, blank space) Next, as shown in FIG.
The hydraulic control circuit 60 that supplies and discharges hydraulic pressure to and from the actuators 46 to 46 will be described. Here, among the above-mentioned actuators, the hydraulic actuator 45' of the 2-4 brake 45 is constituted by a servo piston having an apply port 458' and a release port 45b', and hydraulic pressure is supplied only to the apply port 45a'. 2-4 brake 45 is engaged when hydraulic pressure is supplied to both the boats 45a45b' and when hydraulic pressure is supplied to both ports 45a' and 45b', the 2-4 brake 45 is released. It is supposed to work like this. In addition, other frictional fastening elements 41 to
The actuator of 4.4.46 is constituted by a conventional M] pressure piston and is adapted to engage the frictional engagement element when hydraulic pressure is supplied.

The main component of the pressure control circuit 60 is the main line I'I from the oil pump 13 shown in FIG.
A regulator valve 61 adjusts the pressure of the hydraulic fluid discharged to a predetermined inlet pressure, a manual valve 62 performs range selection by manual operation, and each friction engagement element (actuator) operates according to the gear position. )41-46
and shift valves 6364 and 65 for supplying and discharging hydraulic pressure to and from I-2, 2-3, and 3-4.

The manual valve 62 has an input boat 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 input port e is connected to the 11th second output port ab in the D range and the 2nd range, and to the 1st second output port ab in the lunge.
, a third output port aC, and a fourth output port d in the R range. The first to fourth output lines l1l-114 are connected to each output port a=d, respectively.

In addition, the 1-2.2-3.3-4 shift valve 63
64 and 65 are spools 63a and 64a65a, respectively.
are biased toward the right side in the drawing by a spring (not shown), and these spools 63a, 64
Pilot boats 63b and 64 are on the right side of a and 65a.
b, 65b are provided. A pilot line +15 branched from the main line 110 via line +18 is connected to the pilot port 63b of the 1-2 shift valve 63, and a pilot line +15 is connected to the pilot port 64b of the 2-3 shift valve 64. A pilot line 116 branched from the first output line II+ is connected, and a pilot line +17 led from the main line 110 is connected to the pilot port 65b of the 3-4 shift valve 65. Lines 115, 116 and 117 have I-
2, 2-3 and 3-4 solenoid valves 66.67.
68 is attached. These solenoid valves 66
- 68 drain the pilot lines 115, 116, 117 when each of them is in the ON state, and drain the pilot lines 1-63 of the corresponding shift valves 63-65.
By discharging the pilot pressure in b to 65b, the spools 63a to 65Q are positioned on the right side in the drawing, while each pilot line 115, 116,
By introducing pilot pressure from 117, the spool 63a
.about.65a are positioned on the left side.

Here, these solenoid valves 66 to 68 are turned on and off based on a map preset according to the vehicle speed and engine throttle opening according to signals from the control circuit, and are accordingly turned on and off. each soft valve 6
The positions of the spools 63a to 65a of No. 3 to 65 are switched, and the oil passages leading to the respective frictional engagement elements 41 to 46 are switched, thereby causing these frictional engagement elements 41 to 46 to form the combinations shown in Table 1 above. Thus, the gear position is changed according to the operating condition. In that case, each gear stage and each solenoid valve 66 to 68 are 0N-OF.
The relationship between F and the combination pattern is set as shown in Table 2.
-3 When shifting up, an intermediate pattern is used, which is not shown in the table.

(Left below) On the other hand, each output boat a in the manual valve 62
= 1st to 4th output lines 111 to +14 connected to d
Among them, main line +1 in each forward range of D and 2.1
From the first output line 111 connected to 0, the line +
19 is branched, and the line +19 is used as a forward clutch line and guided to the forward clutch 41 via a one-way orifice 71. Therefore, in the D2+ range, the forward clutch 41 is always engaged. Here, the forward clutch line +1
9 is connected to an ND aggregator 72 via a line 120, which acts as a buffer when the forward clasp is fastened. Reference numeral 73 is a one-way orifice.

Further, the first output line 111 is guided to the 1-2 shift valve 63 and is connected to the 1-2 solenoid valve 6.
6 is in the ON state and the spool 63a is positioned to the right side, it communicates with the servo apply line 121 and connects to the apply port 4 of the servo piston 45' via the two-way orifice 74 which acts as an orifice for the accumulator.
5a'. Therefore, D.2. When the 1-2 solenoid valve 66 is ON in the L range, that is, 2, 3, and 4 speeds in the D range, 2nd and 3rd speeds in the 2 range, and 2 in the L range.
At the same time, hydraulic pressure (i.e., servo apply pressure) is introduced to the apply bow) 45a', and the release port 45a' is
The 2-4 brake 45 is engaged when hydraulic pressure (i.e., servo release pressure) is not introduced to b' (i.e., 2.4 speed in D range, 2nd speed in 2 range, and 2nd speed in L range). . A 1-2 accumulator 75 is connected to the apply boat 45a' via a line 122, which acts as a buffer when the 2-4 brake is engaged.

Further, the first output line I11 is guided to the 3-4 shift valve 65, and the 3-4 solenoid valve 68 is turned off.
line 1 when the spool 65a is located on the left side.
Connects to 23. The line +23 is led to the 2-3 soft valve 64, and communicates with the coast clutch line +24 when the 2-3 solenoid valve 67 is in the ON state and the spool 64a is located on the right side. The coast clutch line +24 reaches the coast clutch line 42 via a one-way orifice 76 and a ball valve 77 for switching oil passages. Therefore, when the 2-3 solenoid valve 67 is in the ON state and the 3-4 solenoid valve 68 is in the OFF' state in the 2 l range, that is, when the 2-3 solenoid valve 67 is in the OFF state,
The coast clutch 42 is engaged at the 1.2 speed and l range.

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. The second output line 112 is 2-
3 solenoid valve 67 is in the OFF state, the spool 64a
is on the left side, 3-4 clutch line +25
The 3-4 clutch line 125 connects to the 3-4 clutch 4-3 via a one-way orifice 78. Therefore, when the 2-3 solenoid valve 67 is in the OFF state in the D and 2 ranges, that is, the 3-4 clutch 43 is engaged in the 3.4 speed of the D range and the 3rd speed of the 2 range. Note that this 3-4 latch line 125 has a 2-3 latch line 125 that acts as a buffer when the 3-4 clutch is activated.
An accumulator 79 is connected. Reference numeral 80 is a one-way orifice.

Here, the line 126 branched from the 3-4 Kuratsuji line +23 is led to the 3-4 shift Halpro 5,
3-4 When the solenoid valve 68 is in the OFF state (that is, the spool 65a is on the left side), the servo release line 12
8.

The servo release line +28 reaches the release port 45b' of the servo piston 45' via a one-way orifice 81. Therefore, D.

2-3 and 3-4 solenoid valves in 2 ranges 67.
68 are both in the OFF state, that is, in the 3rd speed of the D range and the 3rd speed of the 2 range, servo release pressure is introduced into the release port 45b' of the servo piston 45',
-4 brake 45 is released.

Furthermore, the line +29 branched from the front servo release line 128 leads to the coast clutch line +2/l via the coast control valve 82 and the ball valve 77, and reaches the coast clutch 42. Therefore, The coast clutch 42 is also 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 +28.

The third output line 113, which is connected to the main line +10 in the l range by the manual valve 62, is led to the l-2 lift valve 63 via a ball valve 83 that acts as a switching valve, and the 1-2 solenoid valve 66 is turned off.
When the spool 63a is located on the left side in the F state, it is connected to the low reverse brake line +30, and reaches the low reverse brake 46 via the one-way orifice 84 for the accumulator. Therefore, when the 1-2 solenoid valve 66 is in the OFF state in the l range, that is, the low reverse brake 46 is engaged at l speed in the l range.

In this embodiment, the low reverse brake line +30 is provided with a bypass circuit i31 that bypasses the one-way orifice 84. The bypass circuit 131 has a first branch branching from the upstream side of the one-way orifice 84 and reaching the 3-4 shift valve 65.
A branch path 131a and a second branch path 131b leading from the 3-4 shift valve 65 to the downstream side of the one-way orifice 84.
When the 3-4 solenoid valve 68 is in the OFF state and the spool 65a is located on the left side, the eleventh second branch paths 1.31a and 131b are brought into communication.

Note that the low reverse brake line +30 has an N- line which acts as a buffer when the low reverse brake is activated.
An R accumulator 85 is connected.

Main line 1 in the R range of the manual valve 62
The fourth output line +14 connected to the fourth output line +10 is connected to the ball valve 83 via a line 132 branched from the fourth output line +14, while becoming a reverse clutch line +33 and reaching the reverse clutch 44. . Therefore, in R range, 1-2 solenoid valve 6
6 is in the OFF state, the low reverse brake 46 is engaged, and the reverse clutch 44 is always engaged.

The hydraulic control circuit 60 also includes a lock-up shift valve 86 for operating the lock-up clutch 26 in the torque converter 20 shown in FIG. A lock-up control valve 87 is attached to regulate the hydraulic pressure supplied to the inside. Reference numeral 88 is a duty solenoid valve, and 89 is a candle up solenoid valve.

A torque converter line 134 is led from the regulator valve 61 to the lock-up shift valve 86, and a pressure reducing valve 90 is branched from the main line 110 to first and second pilot boats 92b92c provided at both ends. Lines 136 and 137 branched off from the pilot line 135 are connected to each other. The lock-up solenoid valve 89 is attached to the line 136, and when the lock-up solenoid valve 89 is in the ON state, the spool 86a of the lock-up knot valve 86 is located on the right side, so that the torque is increased. The converter line 134 communicates with the torque converter inline +38 leading into the torque converter 20, thereby increasing the internal pressure of the torque converter 20, engaging the lock-up clutch 26, and turning the lock-up solenoid valve 89 into the OFF state. When the spool 86a of the lock-up knot valve 86 moves to the left, the torque converter line 134 communicates with the lock-up release line 139, lock-up release pressure is introduced into the torque converter 20, and the lock-up clutch 26 is released. It is supposed to be done. Reference numeral 94 is a converter relief valve.

In addition to the above configuration, the hydraulic control circuit 60 of this embodiment includes, in addition to the coast timing valve 82, a bypass valve 101 and a 3-2 timing valve for adjusting the supply/discharge timing of hydraulic pressure during each gear shift. +03 is attached.

As described above, the coast timing valve 82 is provided on the line 129 that is branched from the servo release line 128 and leads to the coast clinch line 124 via the ball valve 77, and is branched from the servo apply line +21. Line +40 leads servo apply pressure to one end of spool 82a. When the servo release pressure introduced to the other end of the spool 82a by the line +29 and the biasing force of the spring overcome the servo apply pressure, the line 129
It is designed to communicate. Therefore, this line 1
During 2-3 soft up shifting in the D range and 2 range, where the coast clutch pressure is supplied to the coast clutch 42 via the 29, the 2-4 brake 45 is The coast clutch 42 is then engaged (after the coast clutch 42 is released), thereby preventing a double lock caused by the 2-4 brake 45 and the coast clutch 42 being engaged at the same time. Note that since the servo apply pressure is guided to one end of the spool 83a of the coast timing valve 82,
The timing at which the line 129 is communicated is changed according to the servo apply pressure, and the correspondence between the communication timing and the pressure level of the servo release pressure is appropriately set.

Further, the bypass valve +01 is provided on the bypass line 141 that bypasses the one-way orifice 78 provided in the 3-4 clutch line 125,
The hydraulic pressure downstream of the one-way orifice 78 of the 3-4 clutch line +25 (i.e., 3-4 clutch pressure) is applied to one end of the spool l0Ia, and the regulator valve 61
The slot modulator pressure is controlled by a pressure regulating valve 91 which operates to generate a pressure corresponding to the engine load through a line +42 to the spool IoT.
The bypass line 141 is cut off when the 3-4 clutch pressure rises above a predetermined value and the spool 101a moves to the left. Therefore, the 3-4 clutch pressure is quickly supplied by the bypass line + 41 at the start of supply, but after that the supply is slowed down by the one-way orifice 78, and as a result, during the 2-3 upshift. The timing of engagement of the 3-4 clutch 43 is adjusted. Reference numeral 92 is a duty solenoid valve, and 93 is an accumulator.

Furthermore, the 3-2 timing valve 103 has a first bypass line +43 that bypasses a two-way orifice 74 that is on the servo apply line +21 and acts as an accumulator orifice, and a one-way orifice 7 in the forward clutch line 119.
The second bypass line [44] bypasses the second bypass line [44]. Here, the first bypass line +4
3 is a bypass circuit in the claims.

A pilot line 145 branched from line +18 leading to the main line 110 is connected to one end of the spool 103a of the 3-2 timing valve 103, and a servo release line 128 is connected to an intermediate portion of the spool 103a. Drain line branched from +4
6 is connected to the pilot line 145, and a 3-2 solenoid valve 95 is attached to the pilot line 145. This 3-2 timing valve +03 conducts and shuts off the first and second bypass lines 143, 14.4 during various speed changes by the operation of the 3-2 solenoid valve 95, thereby controlling the oil pressure during these speed changes. Control supply/discharge timing. That is, at the time of I-2 upshift, the first bypass line 143 is first communicated, and the servo apply pressure is applied to the apply boat 458' of the servo piston 45'.
In the second half of the gear shifting operation, the first bypass line 14.3 is cut off when a predetermined period of time has elapsed from the start of the gear shifting operation.
The pour apply pressure is applied to the apply boat 45a' of the servo piston 45' via the two-way orifice 74.
supply slowly. Further, during a 3-2 soft down shift, the drain line +46 is first communicated with the drain port at the start of the shift, and then the drain line I/16 is shut off. Therefore, the servo release pressure is quickly discharged by the drain line 146 during the first half of the gear shift operation, and is gradually discharged by the one-way orifice 8■ which performs a throttling action in the discharge direction on the servo release line 128 during the second half. Become. Furthermore, during the 4-2 soft down shift, the second bypass line 144 is opened in the first half of the shift operation to quickly supply the forward clutch pressure to the forward clutch 41, and in the second half of the shift operation, the By cutting off the second bypass line 144, the forward clutch pressure is gradually supplied to the forward clutch 41 by the throttling action of the one-way orifice 71.

In addition, when shifting to reduce the engagement pressure of the 2-4 brake 45 (i.e., when shifting to discharge the servo apply pressure: 2-3 upshift, 2-1 downshift, 3-1 downshift, and 4-1 downshift). Shift Down Temple), the first
As shown in the figure, the first bypass line 143 is turned on and off by controlling the opening and closing of the 3-2 solenoid valve 95 by a control means 47, which will be described later.

The control means 47 is composed of, for example, a microcomputer, and receives information from the gear stage detection means 48 that detects the shift signal Rs(t) of the automatic transmission, and performs the above-mentioned 3-
This command issues an opening/closing command to the two solenoid valves 95.

Next, referring to the flowchart shown in FIG. 4, 2-
Control at the time of gear change to reduce the engagement pressure of the 4 brakes 45 will be specifically explained.

While driving the vehicle, the shift signal R5(t) is input from the gear position detection means 48 to the control means 47 at any time (
Step S,). When the above information is input, the control means 47
The control proceeds to step S, where the shift signal R8 (L
) is a shift up from 2nd gear to 3rd gear (i.e. 2-3 shift up), and Rs(t)−“2
-3 shift up”, the control means 4
7 proceeds to step S3, where the 3-2 solenoid valve 95 is turned off. Then, the spool 103a
is located on the left side and the first bypass lie: /+
43 is shut off, the servo apply pressure of the 2-4 brake 45 is gradually discharged via the two-way orifice 74. Therefore, during a 2-3 shift up, the 2-4 brake 45 is released by discharging the servo apply pressure, and at the same time, other frictional engagement elements (for example, the 3-4 clutch 43) are engaged. At this time, the servo apply pressure is temporarily discharged on the way, but as mentioned above, by gradually discharging the servo apply pressure through the two-way orifice 74, the servo apply pressure is discharged temporarily during the 2-3 shift up. It is possible to eliminate the occurrence of shift shocks such as engine revving due to both the -4 brake 45 and the 3-4 clutch 43 being in an unengaged state.

On the other hand, in step S2, Rs(t)≠“2-3
If it is determined that the shift is up, the control by the control means 47 proceeds to step S4, and the shift signal R5(t) is determined to be a deceleration to 1st gear (i.e., RS(t) = "2-12-1 downshift or 3"). -1ft down or 4shift down)
It is determined whether or not. Here, Rs(t)−“1
If it is determined that the spool 103a is "decelerating to a high Since the bypass line 143 is connected, the servo apply pressure of the 2-4 brake 45 is quickly discharged via the first bypass line 143, and deceleration to 1st gear is quickly achieved. Note that in step S4, R5(t)≠“
If it is determined that the speed is "deceleration to l speed", the control by the control means 47 is returned to step S1.

As described above, according to this embodiment, the 2-4 brake 45
During gear shifting to release the servo apply pressure of the 2-4 brake gear 45 via the first bypass line +43 that bypasses the two-way orifice 74 that acts as an orifice for the Akicomulator, by opening/closing control of the 3-2 timing valve 103. or the discharge of the servo apply pressure of the 2-4 brake 45 via the two-way orifice 74 depends on the type of shift (for example, a shift that temporarily removes the servo apply pressure of the 2-4 brake or a shift that completely removes it). One timing valve (i.e. 3-2 timing valve 10
3), it is possible to easily perform engagement pressure reduction control according to the type of speed change.

In addition, in the above description, the specific friction engagement element is a 2-4 brake, and the timing valve is a 3-2 timing valve, but the present invention is applicable to the use of other friction engagement elements and timing valves. It can also be applied to

It goes without saying that the present invention is not limited to the configuration of the above-described embodiments, and that the design can be changed as appropriate without departing from the gist of the invention.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of a main part of a hydraulic control circuit in an automatic transmission control device according to an embodiment of the present invention, and FIG. 2 is a skeleton diagram showing the mechanical configuration of an automatic transmission according to an embodiment of the present invention. FIG. 3 is a hydraulic control circuit diagram of the automatic transmission control device according to the embodiment of the present invention, and FIG. 4 is a flowchart for explaining the operation of the automatic transmission control device according to the embodiment of the present invention. . IO... Automatic transmission 30... Speed change gear mechanism 41... Friction engagement element (forward clutch) 42...
...Friction engagement element (coast clutch) 43...Friction engagement element (3-4 clutch) 44...Friction engagement element (
Reverse clutch) 45...Friction engagement element (2-4 brake) 46...Friction engagement element (low reverse brake) 47...Control means 60...Hydraulic pressure control circuit 74...Accumulator orifice (two-way Orifice) 3-2 Solenoid Valve 3-2 Timing Valve Servo Apply Line Bypass Circuit (1st Bypass Line) 95 ・ 畢War畢 - - Moritaka - φCQ-CY) 00-+lN■
Dimension D ■To the O of the size -cY) Dimension size size Dimension ■G■-11

Claims (1)

[Scope of Claims] 1. A speed change gear mechanism, a plurality of friction engagement elements that switch the power transmission path of the speed change gear mechanism, and a hydraulic control circuit that controls supply and discharge of working hydraulic pressure to and from hydraulic actuators of these friction engagement elements. and a control device for an automatic transmission configured to switch engagement states of a plurality of specific friction engagement elements among the friction engagement elements during a predetermined gear shift, the hydraulic control circuit comprising: A bypass circuit that supplies and discharges hydraulic pressure to the specific friction engagement element by bypassing an accumulator orifice provided in an oil path leading to a specific friction engagement element, and a timing for supplying and discharging hydraulic pressure via the bypass circuit. and a control means for controlling opening and closing of the timing valve in accordance with the type of speed change during a speed change in which the engagement pressure of the specific friction engagement element is reduced. An automatic transmission control device featuring: 2. The specific frictional engagement element is a brake equipped with an apply chamber and a release chamber, and the control means closes the timing valve during a shift in which the servo apply pressure of the brake is temporarily released during a shift; 2. The control device for an automatic transmission according to claim 1, wherein the control device for an automatic transmission is configured to operate to open the timing valve during a shift in which the servo apply pressure of the brake is completely released.