JPH04107357A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a shift shock at a low speed range due to an accumulator by providing a back pressure control means to control the back pressure of the accumulator according to a car speed during a shift to a 1-speed at a low speed range. CONSTITUTION:An accumulator 85 to cushion an engaging pressure during engagement of a low reverse brake is located in an oil passage running to a low reverse brake 46 of a hydraulic control circuit. A back pressure control to control the back pressure of the accumulator 85 according to a car speed during a shift to a 1-speed at a low speed range is provided. Namely, during a shift to an R-range, a shift shock is prevented from occurring by means of the accumulator 85 located to the low reverse brake 46, and during a shift to a 1-speed at 1-range, the back pressure of the accumulator 85 is controllable according to a car speed. This constitution relaxes a shift shock, occurring owing to the accumulator 85, at an optimum state.

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, the present invention relates to a control device for an automatic transmission. (called a range)
The present invention relates to a control device for an automatic transmission that acts to prevent shift shock to first gear.

(Prior Art) Generally, automatic transmissions installed in automobiles combine a torque converter and a speed change gear mechanism, and selectively operate 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 regulator 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 and controls each of the above-mentioned actuators. By switching the oil path,
It is composed of a plurality of soft 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 valve with a solenoid valve, Attempts have been made to adapt gear shift control to driving conditions and to perform it with higher precision.

Incidentally, in this type of automatic transmission, an accumulator is attached to the oil passage that supplies hydraulic pressure to each friction engagement element for the purpose of buffering the friction when the friction engagement elements are engaged (for example, Japanese Unexamined Patent Publication 1986-18
(See Publication No. 6055).

(Problems to be Solved by the Invention) In the case of the second known example, for example, although an accumulator is attached to the i+b path leading to the reverse clutch,
The oil path leading to the low reverse brake is configured without an achiemulator. In this case, the actuation shock when shifting to the R range (i.e., when the reverse clutch is engaged) is buffered by the accumulator, but the actuation shock when shifting to 1st gear in the low speed range is avoided. This may become difficult depending on the vehicle speed.

The present invention has been made in view of the above points, and it is an object of the present invention to make it possible to prevent a selection change to the R range and a shift shock in a low speed range using a single accumulator.

(Means for solving the problem) In the invention of claim 1, as a means for solving the problem described above, a speed change gear mechanism, a plurality of frictional engagement elements for switching a 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 the hydraulic actuators of these frictional engagement elements, and switches the engagement state of a plurality of specific frictional engagement elements among the frictional engagement elements at the time of a predetermined speed change. In the set automatic transmission control device, an accumulator is attached to the M (road) leading to the low reverse brake in the hydraulic control circuit for buffering the engagement pressure when the low reverse brake is engaged, and an accumulator is attached to the road leading to the low reverse brake in the low speed range. Back pressure control means is provided for controlling the back pressure of the spacer and mullet in correspondence to the vehicle speed during gear shifting.

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, a bypass for bypassing an accumulator orifice provided in an oil passage leading to the low reverse brake. A circuit is provided, and a shift valve and a solenoid valve that operates the soft valve to open and close the bypass circuit are interposed in the middle of the bypass circuit.

(Function) In the invention of claim 1, the following effects can be obtained by the above means.

In other words, when shifting to the R range, the accumulator attached to the low reverse brake avoids shift shock, and when shifting to 1st gear in the R-range, the back pressure of the accumulator and mullet is applied to the vehicle speed. Due to the corresponding control, the gear shift coupling relaxation by the accumulator is carried out in an optimum manner.

In the invention of claim 2, the following effects can be obtained by the above means.

That is, when the low reverse brake is engaged when the manual valve is operated in a lunge manner, the soft valve provided in the middle of the bypass circuit that bypasses the accumulator orifice provided in the oil path leading to the low reverse brake is switched. Therefore, when the low reverse brake is initially engaged, the hydraulic pressure is quickly supplied to the low reverse brake via the bypass circuit, and the pressure is quickly increased to the accumulator side pressure, but after that, as the bypass circuit is closed, The low rehearth brake is engaged by supplying hydraulic pressure through the accumulator orifice.

(Effects of the Invention) According to the invention of claim I, a speed change gear mechanism, a plurality of friction engagement elements for switching the power transmission path of the speed change gear mechanism, and supply and discharge of working hydraulic pressure to and from the hydraulic actuators of these friction engagement elements are provided. A hydraulic control circuit for controlling an automatic transmission, wherein the control device for an automatic transmission is configured to switch the engagement state of a plurality of specific friction engagement elements among the friction engagement elements during a predetermined gear shift. An accumulator for buffering the engagement pressure when the low reverse brake is engaged is attached to the oil path leading to the low reverse brake in the circuit, and the back pressure of the accumulator is made to correspond to the vehicle speed when shifting to first gear in the low speed range. A back pressure control means is provided to avoid shift shock by an accumulator attached to the low reverse brake when shifting to the R range, and when shifting to 1st speed in the L range, the accumulator is attached to the low reverse brake. The back pressure of the N
-R selection shock and shift shock to 1st speed in the l range can be prevented, and there is an excellent effect that the circuit configuration and hydraulic control can be simplified.

According to the second aspect of the invention, in the automatic transmission control device according to the first aspect, a bypass circuit is provided to bypass the accumulator orifice installed in the oil path leading to the low reverse brake, and the bypass circuit bypasses the accumulator orifice. A shift valve and a solenoid valve for opening and closing the shift valve are interposed in the middle of the circuit to control the switching operation of the shift valve in "Low Reverse Brake Engagement 11!" when the manual valve is operated to the L range. Therefore, when the low reverse brake is initially engaged, hydraulic pressure is supplied to the low reverse brake via the bypass circuit, and the pressure is quickly increased to the accumulator side pressure, and thereafter, as the bypass circuit is closed, Since the low reverse brake is engaged by supplying hydraulic pressure through the accumulator orifice, there is an excellent effect that the shift to l speed can be performed quickly and reliably when the manual valve is operated in l range.

(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 lO 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. By fastening and releasing these, it can be used as a running range; 2. Each of the L 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 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 is supported by the transmission case II via the one-way clutch 24 to increase torque; and the case 21 and the turbine 23.
A lock-up clutch 26 is provided between the engine output shaft 1 and the turbine 23 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 the turbine shaft 2 is connected to the engine output shaft 1, and the pump shaft 12 drives an oil pump 13 provided at the rear end of the automatic transmission IO. 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 diameter small sun gear 31 that is loosely fitted onto the turbine shaft 27, and a small sun gear 31 that is loosely fitted on the turbine shaft 2 behind the small sun gear 31. A large diameter sun gear 32 with a large diameter, a plurality of short pinion gears 33 meshed with the small sun gear 31, a front half of which was meshed with the short pinion gear 33, and a rear half of which was meshed with the large sun gear 32. A long pinion gear 34, 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 sun gear 31, and a coast clutch 42 is interposed in parallel with these clutches 41 and 51. It is set up. 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 II. 2nd One Way Kuratsuji 5 to stop
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 is 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 explained. Here, among the actuators, the hydraulic actuator 45' of the 2-4 brake 45 is constituted by a servo piston having an apply boat 45a' and a release boat 45b', and hydraulic pressure is supplied only to the apply boat 45a'. 2-4 brake 45 is engaged when hydraulic pressure is being supplied to both boats 45a and 45b', and released when hydraulic pressure is being supplied to both boats 45a' and 45b'. It is supposed to work like this. In addition, other frictional fastening elements 4
The actuators 1 to 44 and 46 are constituted by ordinary hydraulic pistons, and are adapted to engage the frictional engagement elements when hydraulic pressure is supplied thereto.

The hydraulic control circuit 60 has a second
A regulator valve 61 adjusts the pressure of hydraulic oil discharged from the illustrated oil pump 13 to the main line +10 to a predetermined line pressure, a manual valve 62 operates to select a range by manual operation, and operates according to the gear position. Shift valves 63, 64, and 65 of 1-2.2-3.3-4 are provided for supplying and discharging hydraulic pressure to each of the frictional engagement elements (actuators) 41 to 46.

The manual valve 62 has an input port e into which line pressure is introduced from the main line 11O, and first to fourth output ports ad, and by movement of the spool 62a,
The input port e is connected to the 11th and 2nd output ports a and b in the D range and the 2 range, to the 1st and 3rd output ports a and C in the L range, and to the 4th output port in the R range. d, respectively. First to fourth output lines 111 to 114 are connected to each output port a to d, respectively.

In addition, the 1-2.2-3.3-4 shift valve 63,
64.65 are spools 63a, 64a, and 65a, respectively.
are biased toward the right side in the drawing by a spring (not shown), and these spools 63a, 64a
, 65a are pilot boats 63b, 64b.
, 6.5b are provided. A pilot line +15 branched from the main line +10 via line +18 is connected to the pilot boat 63b of the 1-2 shift valve 63, and a pilot line +15 is connected to the pilot boat 64b of the 2-3 shift valve 64. A pilot line 11'6 branched from the first output line 111 is connected, and a pilot line +17 led from the main line 110 is connected to the pilot boat 65b of the 3-4 soft valve 65. Pi West lines 115, 116, and 117 each have 1
-2.2-3 and 3-4 solenoid valves 66.67
．． 68 is attached. These solenoid valves 6
6 to 68, when each is in the ON state, the corresponding pilot line +15. ．． 116 and 117 to drain the pilot boat 6 of each corresponding soft valve 63 to 65.
By discharging the pilot pressure in 3b to 65b,
While the spools 63a to 65a are located on the right side of the drawing, each pilot line 115, 11 is connected to the pilot boats 63b to 65b when each is in an OFF state.
Pilot pressure is introduced from spool 6,117, and spool 6
3a to 65a are each located 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 shift 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 turned on and off.
The relationship between F and the combination pattern is set as shown in Table 2, but when a 3-2 downshift is performed, an intermediate pattern is used, which is not shown in the table.

(Left below) On the other hand, the first to fourth output lines Ill to +1 connected to each output boat a=d in the manual valve 62
Main line + in each forward range of D and 2.1 among 4
A line 119 is branched from the first output line I11 connected to the first output line I11, and the line 119 is used as a forward clutch line and is led to the forward clutch 41 via the one-way orifice 7I. Therefore, D,2
．． In the l range, the forward clutch 4I is always engaged. Here, an ND accumulator 72 is connected to the forward clamp line 119 via a line 120, which acts as a buffer when the forward clamp is fastened. Reference numeral 73 is a one-way orifice.

Further, the first output line 111 is guided to the I-2 shift valve 63, and the first output line 111 is led to the I-2 shift valve 63, and
is in the ON state and the spool 63a is positioned to the right side, it communicates with the servo apply line 121 and reaches the apply boat 45a' of the servo piston 45' via the one-way orifice 74. Therefore, D.2. 1 in l range
When the -2 solenoid valve 66 is in the ON state, that is, in the 2nd, 3rd and 4th speeds in the D range, the 2.3rd speed in the 2nd range, and the 2nd speed in the L range, the apply boat 45a' is supplied with hydraulic pressure (i.e. , servo apply pressure) is introduced, and hydraulic pressure (i.e., servo release pressure) is not introduced to the release port 45b' (i.e., 24th speed of D range, 2nd speed of 2 range, and 2nd speed of L range). The 2-4 brake 45 is engaged. Note that the apply boat 45a' includes:
An I-2 accumulator 75 is connected via a line 122, which acts as a buffer when the 2-4 brake is engaged.

Further, the first output line 111 is led to the 3-4 shift valve 65, and the 3-4 solenoid valve 68 is turned off.
In this state, when the spool 65°a is located on the left side, it communicates with the line +23. The line 123 is led to the 2-3 shift valve 64, and the 2-3 solenoid valve 67 is turned on.
In this state, when the spool 64a is located on the right side, it communicates with the coast clutch line +24. The coast clutch line 124 is connected to the coast clutch 42 via a one-way orifice 76 and a ball valve 77 for oil passage switching.
It has reached this point. Therefore, 2. When the 2-3 solenoid valve 67 is in the ON state in the 1 range and the 3-4 solenoid valve 68 is in the OFF state, that is, the 2-3 solenoid valve 68 in the 2 range is in the OFF state.
The coast clutch 42 is engaged in the 12th speed of the speed and l ranges.

Furthermore, the second output line +12, which communicates with the main line +10 at D2, is led to a 2-3 shift valve 64. Then, the second output line +12 is 2-
3 solenoid valve 67 is in the OFF state, the spool 64a
is located on the left side, the 3-4 clutch line 125
The 3-4 cladding line +25 reaches the 3-4 cladding 43 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 speed in the D range,
The 3-4 clutch 43 is engaged in the 3rd speed of the 2nd range. In addition, this 3-4 Kuratsuji line +25 includes:
A 2-3 accumulator 79 is connected which acts as a buffer when the 3-4 clutch is activated. Reference numeral 80 is a one-way orifice.

Here, the line 126 branched from the 3-4 Kurazzi line +23 is led to the 3-4 shift valve 65,
When the 3-4 solenoid valve 68 is in the OFF state (that is, the spool 65a is on the left side), it communicates with the line 127,
The servo release line 128 is connected to the servo release line 128 via the 2-3 timing valve 102. The release line 128 reaches the release port 45b' of the servo piston 45' via the one-way orifice 81. Therefore, when both the 2-3 and 3-4 solenoid valves 67 and 68 are in the OFF state in the D and 2 ranges, that is, in the 3rd gear of the D range and the 2nd range, the release photo 45b' of the servo piston 45' A servo release pressure is introduced to release the 2-4 brake 45.

Furthermore, a line 129 branched from the servo release line 128 is connected to the coast control valve 8.
2 and the ball valve 77 to the coast clutch line 124 and reach 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 128.

The third output line 113, which is connected to the main line +10 in the L range by the manual valve 62, is guided to the 1-2 shift valve 63 via the ball valve 83, which 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 130, and reaches the low reverse brake 46 via the one-way orifice 84 for Akiko and Muleta. Therefore, when the l-2 solenoid valve 66 is in the OFF state in the l range, that is, in the first gear of the l range, the low reverse brake 46 is engaged. That is, in this embodiment, the third output line +13 constitutes a low speed range circuit in the manual valve 62.

In this embodiment, the low reverse brake line 130 is provided with a bypass circuit +31 that bypasses the one-way orifice 84. The bypass circuit +31 is a first branch branching from the second flow 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 first and second branch paths +31a and 13lb 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.
R accumulators 8 and 5 are connected.

Main line 1 in the R range of the manual valve 62
The fourth output line +14 connected to the fourth output line II/1 is connected to the pawl valve 83 via the line I32 branched from the fourth output line II/1, and becomes a reverse clutch line 133 and is connected to the reverse clutch 44. It has been reached. Therefore, in the R range, the low reverse brake 46 is engaged and the reverse clutch 44 is engaged only when the -2 solenoid valve 66 is in the OFF state.
is always concluded. In other words, in this embodiment, the fourth
The output line 114 and a line 132 branched from the fourth output horn line 114 constitute a reverse range circuit in the manual valve 62.

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 adjust the hydraulic pressure supplied to the engine. Reference numeral 88 is a duty solenoid valve, and 89 is a lock-up solenoid valve.

The lock-up shift valve 86 has one leg.

Rake valve 61 to 1-lux converter line 134
Lines 136 and 13 branched from the main line +10 and from the pilot line +35 equipped with a pressure reducing valve 90 are connected to the first and second pilot boats 92b and 92c provided at both ends.
7 are connected to each other. And the line +3
6 is attached with the lock-up solenoid valve 89, and the lock-up solenoid valve 89 is
When the spool 86a of the lock-up shift valve 86 is located on the right side in the N state, the torque converter line 134 communicates with the torque converter inline 138 leading into the torque converter 20, thereby reducing the internal pressure of the torque converter 20. increases and the lock-up clutch 26 is engaged, and when the lock-up solenoid valve 89 is turned off and the spool 86a of the lock amplifier shift valve 86 moves to the left, the torque converter line +34 is connected to the lock-up release line 139. The lockup release pressure is introduced into the torque converter 20, and the lockup clutch 26 is released. Reference numeral 94 is a converter relief valve.

In addition to the above configuration, the hydraulic control circuit 60 of this embodiment includes the coast timing valves 82 and 2-3 for adjusting the supply/discharge timing of M1 pressure during each gear shift.
In addition to the timing valve 102, a lot of bypass valves
and a 3-2 timing valve 103 are attached.

As described above, the coast timing valve 82 is provided on the line 129 which is branched from the servo release line 128 and leads to the coast clasody line 124 via the ball valve 77, and is branched from the servo bridle line +21. Servo apply pressure is guided to one end of the spool 82a by a line 140. When the servo release pressure introduced to the other end of the spool 82a by the line 129 and the biasing force of the spring overcome the servo apply pressure, the line 129
It is designed to communicate. Therefore, this line +
During 2-3 upshifts in the D range and 2 range, where 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 of communicating the line 129 will be changed according to the servo apply pressure, and the correspondence and relationship between the communication timing and the pressure level of the servo release pressure will be 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 Kuratsuji line +25,
Hydraulic pressure downstream of the one-way orifice 78 of the 3-4 clutch line 125 (i.e., 3-4 clutch pressure) is connected to one end of the spool 101a by the regulator valve 61.
The slot monulator pressure is guided from the spool 101 through a line +42 and is controlled by a pressure regulating valve 91 which acts to generate a pressure corresponding to the engine load.
The bypass line I41 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 thereafter the supply is slowed down by the one-way orifice 78, and this causes The timing of fastening the 3-4 clutch 43 will be adjusted. Reference numeral 92 is a duty solenoid valve, and 93 is an accumulator.

Furthermore, the 2-3 timing valve 102 is a 3-4 timing valve 102.
The 3-4 clutch line 1 is installed at one end of the spool 102a, and is interposed in the communication area between the line 127 led from the shift valve 65 and the servo release line 128.
The hydraulic pressure in 25 (ie, 3-4 clutch pressure) is introduced to the other end as servo release pressure. Then, the servo release line +28 is connected to or drained from the line 127 by the action of the 3-4 clutch pressure and the servo release pressure, and the servo release pressure is regulated in accordance with the 3-4 clutch pressure. .

Further, the 3-2 timing valve 103 is connected to a first bypass line 143 that bypasses the one-way orifice 74 on the servo apply line 121 and a second bypass line 144 that bypasses the one-way orifice 71 on the forward cludge line 119. It is set across. A pilot line 14 branched from line +18 leading to the main line 110 is connected to one end of the spool 103a of the timing valve 103.
5 is connected to the intermediate portion of the spool l03a,
A drain line +46 branched from the servo release line 128 is connected to the pilot line 14.
5 is attached with a 3-2 solenoid valve 95. The timing valve 103 is operated by the first and second bypass lines 143 during the 1-2 upshift, the 3-2 downshift, and the 4-2 downshift by the operation of the 3-2 solenoid valve 95. 1
44 to control the supply/discharge timing of hydraulic pressure during these speed changes. In other words, during the I-2 upshift, first the first bypass line 143 is communicated, and the servo apply pressure is promptly supplied to the apply boat 458' of the servo piston 45'. By cutting off the first bypass line +43 when the shift period has elapsed, the servo apply pressure is gradually supplied to the apply boat 458' of the servo piston 45' via the one-way orifice 74 in the latter half of the shift operation. Also, during 3-2 downshifting, the drain line +
46 to the drain boat, and then the drain line 146 is shut off. Therefore, the servo release pressure is
In the first half of the speed change operation, the fluid is quickly discharged by the drain line 146, and in the second half, it is slowly discharged by the one-way orifice 81 that performs a throttling action in the discharge direction on the servo release line 128. Furthermore, during the 4-2 downshift, the second bypass line 144 is first opened during the first half of the shift operation to quickly supply forward clutch pressure to the forward clutch 41, and during the second half of the shift operation, the By cutting off the second bypass line +44, the forward clutch pressure is gradually supplied to the forward clutch 41 by the throttling action of the one-way orifice 71.

On the other hand, the back pressure boats 72a, 75a 79a 85a in the accumulators 72, 75, 79, 85,
A main line +10 is connected to each accumulator 72 by hydraulic pressure supplied from the main line +10.
．． 75, 79, and 85 are to be controlled. A pressure regulating valve 91 having the pressure reducing valve 90 and a duty solenoid valve 92 is attached to the main line +10. The duty solenoid valve 92 drains the main line 110 when in the ON state, and drains the main line 110 when the duty solenoid valve 92 is in the ON state.
It acts to leak the back pressure acting on 85, and opens and closes periodically (in other words, ON/OT;
F') controlled. Therefore, the back pressure supplied from the main line 110 is controlled according to the duty rate (the valve opening time ratio in one cycle) of the duty solenoid valve 92.

In the hydraulic control circuit 60 configured as described above, as shown in FIG.
A control means 47 is provided for controlling the opening and closing of the valves 6, 67, and 68, as well as controlling the duty of the duty solenoid valve 92.

The control means 47 is composed of, for example, a microcomputer, and controls the range signal Rg(t
), a shift signal detection means 49 that detects the shift signal H, a vehicle speed detection means 50 that detects the vehicle speed of the automobile, and an oil temperature detection means 51 that detects the oil temperature.
Based on the information from 1-2.2-3 and 3-4 above.
It issues opening/closing commands to the solenoid valves 66, 67, and 68, and a duty control command to the duty solenoid valve 92. That is, in the case of this embodiment, the pressure reducing valve 90, the pressure regulating valve 91, the duty solenoid valve 92, and the control means 47 constitute the back pressure control means in the claims. In addition, in the case of this example, the above 1-2.2-3
The opening and closing of the 3-4 solenoid valves 66, 67, and 68 are controlled by SQL patterns (1) and (2) shown in Table 3 below.

Table 3 Next, control in the I range will be specifically explained with reference to the flowchart shown in FIG.

While the vehicle is in operation, the control means 47 receives the range signal Rg(t), the speed change signal (, the vehicle speed, and the oil temperature T is input at any time (step S1). If the above information is available, the control by the control means 47 proceeds to step S2, where it is determined whether the range signal Rg(t) is a range signal, and Rg(t )-1, it is determined in step S3 whether the shift signal ■( is in 1st gear or not. Then, in step S3
If it is determined that H-"]", the process proceeds to step S4, and the duty ratio for the duty solenoid valve 92 is adjusted based on the duty ratio D(V) read from the map shown in FIG. 5 in accordance with the vehicle speed V. Control takes place. Therefore, the back pressure of the N-R accumulator 85 is
It will be controlled in accordance with the vehicle speed, and the accumulator side pressure will be formed in an optimal state. after that,
The control by the control means 47 proceeds to step S5, and the solenoid valves 66, 67, 68 are controlled according to the SQL pattern (+).
After being controlled to open and close in the state shown by for a predetermined time t (T), the process proceeds to step S6, and the opening and closing control is performed to the state shown in pattern (2). The time t(T) is calculated as a function determined by the oil temperature T,
It is read from the map shown in FIG. In other words, oil temperature T
is low (that is, when the oil viscosity is high), the time t(
T) is long and the time t(T) is determined to be short when the oil temperature T is high (that is, when the oil viscosity is low). Therefore, by setting the solenoid valves 66, 67, and 68 to the state shown in SQL pattern (1),
The time t (T) during which the bypass circuit +31 that bypasses the one-way orifice 84 is communicated and the hydraulic pressure is quickly supplied to the low reverse brake 46 via the bypass circuit +31 is determined in accordance with the viscosity of the oil. becomes. As a result, the N-R accumulator 8
5, the lateral pressure can be quickly formed. Note that the solenoid valve 66 after that
By shifting to the S Q L pattern (2) of 67.68, hydraulic pressure is gradually supplied to the low reverse brake 46 via the one-way orifice 84. Thereafter, in step S7, the shift signal H is determined,
Solenoid valve 66 while it is determined to be H-“1”
．． 67.68 is s or r, and the state of pattern (2) is maintained. Then, in step S7, I≠“1”
If it is determined that
ON/OFF control shown in the table) is performed (step S8
).

''-As described above, according to this embodiment, when the manual valve 62 is shifted to lunge and the automatic transmission is shifted to 1st speed during high-speed driving, at the initial stage of engagement of the low reverse brake 46, , bypass circuit +31
The quick hydraulic pressure supply through the one-way orifice 84 speeds up the side pressure formation, and the subsequent gradual hydraulic pressure supply through the one-way orifice 84 causes the low reverse brake 46 to be engaged, and the low reverse brake 4
N- to buffer the shift shock when tightening 6.
Since the back pressure of the R akicomulator 85 is controlled according to the vehicle speed by the action of the backpressure control means, it is possible to form the akicomulator shelf pressure in an optimal state corresponding to the vehicle speed.

In the above embodiment, the bypass circuit 13+ is opened and closed by the 3-4 soft valve 65, but the bypass circuit 131 may be opened and closed by the 2-3 shift valve 64.

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 drawings]

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, FIG. 4 is a flowchart for explaining the operation of the automatic transmission control device according to the embodiment of the present invention, and FIG. Figure 5 is a map for reading out the duty ratio D(V) obtained as a function of vehicle speed V.
The figure is a map for calculating the holding time of the SOL pattern (+) from the oil temperature in 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, 62, 63, 64, 65, 66, 67, 68・84 ・85 ・90 ・9l ・92 ・+10 ・Hydraulic control circuit ・Manual valve ・1-2 shift valve ・2-3 shift valve ・3-4 shift valve ・1-2 solenoid valve ・2-3 solenoid valve・3-4 solenoid valve ・Accumulator orifice (one-way orifice) ・N-R accumulator ・Pressure reducing valve ・Pressure regulating valve ・Duty solenoid valve ・Main line ・Low reverse spray line ・Bypass circuit D (V) No. 5 figure

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 control device comprising: a low reverse in the hydraulic control circuit; The oil path leading to the brake is equipped with an accumulator that buffers the engagement pressure when the low reverse brake is engaged, and the back pressure of the accumulator is controlled in accordance with the vehicle speed when shifting to 1st gear in the low speed range. A control device for an automatic transmission, characterized in that it is equipped with a back pressure control means. 2. A bypass circuit that bypasses an accumulator orifice provided in the oil passage leading to the low reverse brake, a shift valve interposed in the middle of the bypass circuit, and the shift valve operated to open and close the bypass circuit. 2. The automatic transmission control device according to claim 1, further comprising a solenoid valve for controlling the automatic transmission.