JP3115303B2 - Control device for automatic transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for an automatic transmission, and more particularly to a select shock to a reverse range (hereinafter referred to as an R range) and a low speed range (hereinafter referred to as one range). The present invention relates to a control device for an automatic transmission that acts to prevent a shift shock to the first speed at the first speed.

2. Description of the Related Art Generally, an automatic transmission mounted on an automobile combines a torque converter and a transmission gear mechanism, and selectively operates a power transmission path of the transmission gear mechanism by a plurality of frictional engagement elements such as clutches and brakes. And automatically shifts to a predetermined gear.

This type of automatic transmission is provided with a hydraulic control circuit for controlling the supply and discharge of hydraulic pressure to the actuator of each of the frictional engagement elements. This hydraulic control circuit is, specifically,
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 an oil passage that operates according to the operating state and switches the oil passage leading to each of the actuators provide a plurality of frictions. It is composed of a plurality of shift valves for selectively operating a fastening element, and various valves for performing other auxiliary functions. In particular, in recent years, the shift control is performed by driving the shift valve by a solenoid valve. Attempts have been made to adapt to the operating conditions so as to be able to perform with higher accuracy.

By the way, in this type of automatic transmission, an accumulator is attached to an oil passage for supplying a hydraulic pressure to each friction tightening element in order to buffer a shock at the time of engagement of the friction engagement element (for example, JP-A-63-1860
No. 55).

(Problems to be Solved by the Invention) In the case of the above-mentioned known example, for example, an accumulator is attached to an oil passage leading to a reverse clutch, but an accumulator is not attached to an oil passage leading to a low reverse brake. Have been. In this case, the operation shock when shifting to the R range (that is, when the reverse clutch is engaged) is buffered by the accumulator, but avoiding the operation shock when shifting to the first speed in the low speed range is achieved by the vehicle speed. Depending on the situation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to enable a single accumulator to prevent a select shock to an R range and a shift shock in a low speed range.

(Means for Solving the Problems) In the invention of claim 1, as a means for solving the above problems, a transmission gear mechanism, a plurality of friction fastening elements for switching a power transmission path of the transmission gear mechanism, and A hydraulic control circuit for controlling the supply and discharge of operating hydraulic pressure to and from the hydraulic actuator of the frictional engagement element, wherein a plurality of specific frictional engagement elements among the frictional engagement elements are switched during a predetermined gear change. A control device for an automatic transmission, wherein an oil passage to a low-reverse brake engaged when the first speed in the low-speed range and the reverse range is selected in the hydraulic control circuit is provided when the first speed in the low-speed range or the reverse range is selected. A common accumulator is provided for buffering the engagement pressure when the low reverse brake is engaged, and is used when shifting to the first speed in the low speed range. In addition, a back pressure control means for controlling the back pressure of the accumulator in accordance with the vehicle speed is provided.

According to a second aspect of the present invention, there is provided a control device for an automatic transmission according to the first aspect, wherein a bypass for bypassing an accumulator orifice provided in an oil passage leading to the low reverse brake is provided. A circuit is additionally provided, and a shift valve and a solenoid valve that operates the shift valve to open and close the bypass circuit are provided in the middle of the bypass circuit.

(Operation) In the invention of claim 1, the following operation is obtained by the above means.

That is, when shifting to the R range, the shift shock is avoided by the accumulator attached to the low reverse brake, and when shifting to the first speed in one range, the back pressure of the accumulator corresponds to the vehicle speed. As a result, the shift shock is alleviated by the accumulator in an optimum state.

According to the second aspect of the present invention, 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 to one range, the shift valve provided in the middle of the bypass circuit that bypasses the accumulator orifice provided in the oil passage leading to the low reverse brake is switched. By the operation, when the low reverse brake is initially engaged, the hydraulic pressure is quickly supplied to the low reverse brake via the bypass circuit, and a rapid pressure increase to the accumulator shelf pressure is obtained, but thereafter, the bypass circuit is closed. Accordingly, the low reverse brake is engaged by supplying hydraulic pressure through the accumulator orifice.

(Effect of the Invention) According to the invention of claim 1, a speed change gear mechanism, a plurality of friction fastening elements for switching a power transmission path of the speed change gear mechanism, and supply / discharge of operating hydraulic pressure to a hydraulic actuator of the friction speed fastening elements. And a hydraulic control circuit for controlling a hydraulic control circuit for controlling the engagement state of a plurality of specific frictional engagement elements among the frictional engagement elements during a predetermined shift. An accumulator for buffering the engagement pressure when the low reverse brake is engaged is attached to the oil passage leading to the low reverse brake in the circuit, and the back pressure of the accumulator corresponds to the vehicle speed only when shifting to the first speed in the low speed range. A back pressure control means is provided to control the accumulator attached to the low reverse brake when shifting to the R range. Gear shift shock to avoid
At the time of shifting to the first speed in the range, the back pressure of the accumulator is controlled according to the vehicle speed, so that the shift shock can be alleviated by the accumulator in an optimal state. , NR select shock and shift shock to the first speed in one 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 present invention, in the control device for an automatic transmission according to the first aspect, a bypass circuit for bypassing an accumulator orifice provided in an oil passage leading to a low reverse brake is additionally provided. On the way, when the low reverse brake is engaged when the manual valve is operated to one range, a low reverse brake is provided by interposing a shift valve and a solenoid valve that opens and closes the shift valve. At the beginning of brake application, hydraulic pressure is supplied to the low reverse brake via the bypass circuit,
Since a rapid pressure increase up to the accumulator shelf pressure can be obtained, and thereafter, the low reverse brake is engaged by hydraulic pressure supply through the accumulator orifice with the closing of the bypass circuit. There is an excellent effect that the shift to the first speed can be performed quickly and reliably when the valve is operated in one range.

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

First, a mechanical configuration of the automatic transmission according to the present embodiment will be described with reference to FIG.

The automatic transmission 10 of the present embodiment has, as main components,
A torque converter 20, a transmission 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 for switching a power transmission path of the transmission gear mechanism 30, and a one-way clutch 51, 52
With the engagement and disengagement of these, each range of D, 2, L, R as a driving range, 1st to 4th speed in D range,
The first to third speeds in the range and the first to second speeds in the one range can be obtained.

The torque converter 20 includes a pump 22 fixed in a case 21 connected to the engine output shaft 1,
And a one-way clutch 24 disposed between the turbine 23 and the pump 22 and connected to the transmission case 11.
Stator 25 which is supported via
And a lock-up clutch 26 provided between the case 21 and the turbine 23 and directly connecting the engine output shaft 1 and the turbine 23 via the case 21. The rotation of the turbine 23 is output to the transmission gear mechanism 30 via a turbine shaft 27. Here, the engine output shaft 1 has a turbine shaft
The pump shaft 12 penetrating through the inside 27 is connected, and the pump shaft 12 drives an oil pump 13 provided at the rear end of the automatic transmission 10.

On the other hand, the transmission gear mechanism 30 is constituted by a Ravigneaux type planetary gear device, and has a small diameter small sun gear 31 loosely fitted on the turbine shaft 27, and is loosely fitted on the turbine shaft 27 also behind the small sun gear 31. Large diameter large sun gear 32, and a plurality of short pinion gears 33 meshed with the small sun gear 31,
A long pinion gear 34 having a front half meshed with the short pinion gear 33 and a rear half meshed with the large sun gear 32, a carrier 35 rotatably supporting the long pinion gear 34 and the short pinion gear 33, and the long pinion gear 34. And a ring gear 36 meshed with the front half of the ring gear.

And, the turbine shaft 27 and the small sun gear
A forward clutch 41 and a first one-way clutch 51 are interposed in series between the clutch 31 and the clutch 31, and a coast clutch 42 is interposed in parallel with these clutches 41 and 51. A 3-4 clutch 43 is interposed between the turbine shaft 27 and the carrier 35, while a reverse clutch 44 is interposed between the turbine shaft 27 and the large sun gear 32. Further, the large sun gear
Large sun gear 32
A 2-4 brake 45 serving as a band brake for fixing the carrier 35 is provided. A second one-way clutch 52 for receiving a reaction force of the carrier 35 and a carrier 35 are provided between the carrier 35 and the transmission case 11. A fixed low reverse brake 46 is 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.

The relationship between the operating state of each of the frictional engagement elements 41 to 46 such as the clutches and brakes and the one-way clutches 51 and 52 and the shift speed is well known and will not be described in detail, and is shown in Table 1. In Table 1, a circle indicates a fastening state, and a column * indicates coasting idling.

Next, the hydraulic control circuit 60 for supplying and discharging the hydraulic pressure to and from the actuators of the friction fastening elements 41 to 46 will be described with reference to FIG. Here, among the actuators,
The hydraulic actuator 45 'of the 2-4 brake 45 is constituted by a servo piston having an apply port 45a' and a release port 45b '.
When hydraulic pressure is supplied only to the 2-4 brake 45
When the hydraulic pressure is not supplied to both the ports 45a 'and 45b' and when the hydraulic pressure is supplied to both the ports 45a 'and 45b', it acts to release the 2-4 brake 45. ing. Also, other friction fastening elements
The actuators 41 to 44, 46 are constituted by ordinary hydraulic pistons, and are adapted to fasten the friction fastening elements when hydraulic pressure is supplied.

The hydraulic control circuit 60 includes, as a main component, a second
A regulator valve 61 for adjusting the pressure of the hydraulic oil discharged from the oil pump 13 to the main line 110 to a predetermined line pressure, a manual valve 62 for selecting a range by manual operation, and actuated according to a shift speed 1-2, 2-3, and 3-4 for supplying and discharging the hydraulic pressure to and from the friction engagement elements (actuators) 41 to 46, respectively.
65 and.

The manual valve 62 has an input port e into which line pressure is introduced from the main line 110, and first to fourth output ports a to d. When the spool 62a moves, the input port e And the first and second output ports a and b in the second range, and the first and second output ports in the first range.
The third output ports a and c are connected to the fourth output port d in the R range, respectively. The first to fourth output lines 111 to 114 are connected to the output ports a to d, respectively.

In addition, the 1-2, 2-3, and 3-4 shift valves 63, 6
Each of the spools 63a, 64a, 65a is biased to the right by a spring (not shown) in the drawing, and a pilot port 63b, 64b and 65b are provided. The pilot port 63b of the 1-2 shift valve 63
Is connected to a pilot line 115 branched from the main line 110 via a line 118. A pilot line 116 branched from the first output line 111 is connected to a pilot port 64b of the 2-3 shift valve 64. Connected to the pilot port 65b of the 3-4 shift valve 65.
Is connected to a pilot line 117 led from the main line 110, and these pilot lines 1
15, 116 and 117 have 1-2, 2-3 and 3-4, respectively.
Solenoid valves 66, 67, and 68 are provided. These solenoid valves 66 to 68 cause the pilot lines 115, 116, 117 to drain when each is ON,
Pilot port 63b for each corresponding shift valve 63-65
The spools 63a to 65a are positioned on the right side in the drawing by discharging the pilot pressure in the pilot ports 63b to 65b, while the pilot pressure is introduced from the pilot lines 115, 116, and 117 to the pilot ports 63b to 65b when each is in the OFF state. Thus, the spools 63a to 65a are respectively located on the left side.

Here, these solenoid valves 66 to 68 are turned ON / OFF based on a map set in advance according to the vehicle speed of the vehicle and the throttle opening of the engine according to a signal from the control circuit. The positions of the spools 63a to 65a of each shift valve 63 to 65 are switched so that each frictional fastening element
The oil passages leading to 41 to 46 are switched, so that these friction fastening elements 41 to 46 are to be fastened in the combination shown in Table 1 above, and thus the gear is in the operating state. It is to be switched accordingly. In this case, the relationship between each shift speed and the combination pattern of ON / OFF of each of the solenoid valves 66 to 68 is set as shown in Table 2; It passes through the intermediate pattern shown.

On the other hand, of the first to fourth output lines 111 to 114 connected to the respective output ports a to d of the manual valve 62, the first output connected to the main line 110 in each forward range of D, 2, 1 is provided. From the line 111, a line 119 is branched, and the line 119 is formed as a forward clutch line and is led to the forward clutch 41 via the one-way orifice 71. Therefore, in the D, 2, 1 range, the forward clutch 41 is always engaged. Here, the forward clutch line 119 is connected via a line 120 to an ND accumulator 72 which acts as a buffer when the forward clutch is engaged. Reference numeral 73 denotes a one-way orifice.

Further, the first output line 111 is led to the 1-2 shift valve 63, and the 1-2 solenoid valve 66 is turned on.
When the spool 63a moves to the right side and is in the state, it communicates with the servo apply line 121, and the one-way orifice 74
To the apply port 45a of the servo piston 45 '. Therefore, the 1-2 solenoid valve 66 in the D, 2,1 range
Is in the ON state, that is, at 2, 3, 4 speed in the D range, 2, 3 speed in the 2 range, and 2 speed in the 1 range, the hydraulic pressure (that is, the servo-apply pressure) is applied to the apply port 45a '. When the hydraulic pressure (ie, servo release pressure) is not introduced into the release port 45b '(that is, the D range 2,
4-4, 2-range 2nd and 1-range 2nd) 2-4
The brake 45 is engaged. In addition, the aforementioned apply port 45
a 'is connected via a line 122 to a 1-2 accumulator 75 which acts as a buffer when the 2-4 brake is engaged.

The first output line 111 is guided to the 3-4 shift valve 65, and communicates with the line 123 when the spool 65a is located on the left side with the 3-4 solenoid valve 68 in the OFF state. The line 123 is led to a 2-3 shift valve 64,
When the 2-3 solenoid valve 67 is ON and the spool 64a is located on the right side, it communicates with the coast clutch line 124. The coast clutch line 124 reaches the coast clutch 42 via a one-way orifice 76 and a ball valve 77 for switching an oil passage. Accordingly, when the 2-3 solenoid valve 67 is turned on and the 3-4 solenoid valve 68 is turned off in the 2,1 range, that is, when the coast clutch 42 is turned on in the 2nd speed of the 2nd range and the 1st and 2nd speeds of the 1st range.
Is concluded. Further, the second output line 112 communicating with the main line 110 in the D, 2 range is provided with a 2-3 shift valve 64.
Is led to. And, the second output line 112 is 2
When the spool 64a is located on the left side with the -3 solenoid valve 67 turned off, the 3-4 clutch line 125 communicates with the 3-4 clutch line 125 via the one-way orifice 78 to the 3-4 clutch 43. Has reached. Accordingly, when the 2-3 solenoid valve 67 is in the OFF state in the D and 2 ranges, that is, in the 3rd and 4th speeds in the D range and the 3rd speed in the 3rd speed in the 2 range,
The four clutch 43 is engaged. Note that this 3-
The four-clutch line 125 is connected to a 2-3 accumulator 79 that functions as a buffer when the 3-4 clutch operates. Reference numeral 80 denotes a one-way orifice.

Here, the line 126 branched from the 3-4 clutch line 123 is led to the 3-4 shift valve 65,
When the 4-solenoid valve 68 is in the OFF state (that is, when the spool 65a is on the left side), it communicates with the line 127 and communicates with the servo release line 128 via the 2-3 timing valve 102. The servo release line 128 extends through a one-way orifice 81 to a release port 45b 'of the servo piston 45'. Therefore, 2-3 in D, 2 range
When both the 3-4 solenoid valve 67.68 and the 3-4 solenoid valve 67 are OFF, that is, at the 3rd speed of the D range and at the 3rd speed of the 2 range,
The servo release pressure is introduced into the release port 45b 'of the servo piston 45', and the 2-4 brake 45 is released.

Further, a line 129 branched from the servo release line 128 is connected to a coast clutch line 124 via the coast control valve 82 and the ball valve 77, and reaches the coast clutch 42. Therefore, D where hydraulic pressure is introduced into the servo release line 128
The coast clutch 42 is also engaged in the third speed of the range and the third speed of the two ranges.

The third output line 113 communicating with the main line 110 in one range by the manual valve 62 is taken by the 1-2 shift valve 63 via the ball valve 83 acting 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 this state, the spool 63a communicates with the low reverse brake line 130 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 one range, that is, when the low reverse brake is
46 is concluded. That is, in the present embodiment, the third output line 113 forms a low-speed range circuit in the manual valve 62.

In the present embodiment, the low reverse brake line 130 is provided with a bypass circuit 131 that bypasses the one-way orifice 84. The bypass circuit 1
31 is a first branch 131a that branches from the upstream side of the one-way orifice 84 and reaches the 3-4 shift valve 65;
A third branch 131b extending from the 3-4 shift valve 65 to the downstream side of the one-way orifice 84;
When the four solenoid valve 68 is in the OFF state and the spool 658 is located on the left side, the first and second branch paths 131a and 131b are communicated.

The low reverse brake line 130 has an N-acting buffer which acts as a buffer when the low reverse brake is activated.
An R accumulator 85 is connected.

Main line 11 with R range of manual valve 62
The fourth output line 114 leading to 0 is connected to the fourth output line 11
4 through a line 132 branched from
The reverse clutch line 133 is connected to the reverse clutch 44. Therefore, in the R range, the low reverse brake 46 is engaged and the reverse clutch 44 is always engaged only when the 1-2 solenoid valve 66 is in the OFF state. That is, in the present embodiment, the fourth output line 114 and the line 132 branched from the fourth output line 114 are connected to the manual valve.
The reverse range circuit in 62 is to be configured.

The hydraulic control circuit 60 includes a lock-up shift valve 86 for operating the lock-up clutch 26 in the torque converter 20 shown in FIG. And a lock-up control valve 87 that regulates the hydraulic pressure supplied to the vehicle. Reference numeral 88 denotes a duty solenoid valve, and reference numeral 89 denotes a lock-up solenoid valve.

In the lock-up shift valve 86, the torque converter line 134 is taken from the regulator valve 61, and first and second pilot ports 92b and 92c provided at both ends are branched from the main line 110 and reduced in pressure. Lines 136 and 137 branched from a pilot line 135 provided with the valve 90 are respectively connected. The line 136 is provided with the lock-up solenoid valve 89, and when the lock-up solenoid valve 89 is ON, the lock-up shift valve 86
Is located on the right side, the torque converter line 134 communicates with the torque converter inline 138 communicating with the inside of the torque converter 20, whereby the internal pressure of the torque converter 20 increases and the lock-up clutch 26 is engaged. When the lock-up solenoid valve 89 is turned off and the spool 86a of the lock-up shift valve 86 moves to the left, the torque converter line 134 communicates with the lock-up release line 139, and the torque converter line 134 The lock-up release pressure is introduced, and the lock-up clutch 26 is released. Reference numeral 94 denotes a converter relief valve.

In addition to the above configuration, in addition to the coast timing valve 82 and the 2-3 timing valve 102, the hydraulic control circuit 60 of the present embodiment includes a bypass valve for adjusting hydraulic pressure supply / discharge timing at each shift. 101 and 3
A -2 timing valve 103 is provided.

As described above, the coast timing valve 82 is provided on a line 129 that is branched from the servo release line 128 and communicates with the coast clutch line 124 via the ball valve 77.
The servo apply pressure is guided to one end of the spool 82a by a line 140 branched from the spool 82a. When the servo release pressure introduced to the other end of the spool 82a by the line 129 and the urging force of the spring overcome the servo apply pressure, the line 129 is connected. Therefore, during the 2-3 shift-up shift in the D range and the 2 range where the coast clutch pressure is supplied to the coast clutch 42 via the line 129, the servo release pressure is sufficiently increased (that is, 2-4). The coast clutch 42 is engaged (after the brake 45 is surely released), and double locking due to the simultaneous engagement of the 2-4 brake 45 and the coast clutch 42 is prevented. Since the servo apply pressure is guided to one end of the spool 83a of the coast timing valve 82, the timing for communicating the line 129 is changed according to the servo apply pressure, and the communication timing and the servo release pressure are changed. Is set appropriately.

The bypass valve 101 is provided on a 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 (-4) clutch line 125 (that is, the 3-4 clutch pressure) is the spool 101a.
At one end of the spool 101a is introduced from the regulator valve 61 and is pressure-controlled by a pressure regulating valve 91 acting to generate a pressure corresponding to the engine load. The 3-4 clutch pressure rises above a predetermined value and the spool
When the 101a moves to the left, the bypass line 141 is cut off. Accordingly, the 3-4 clutch pressure is supplied promptly by the bypass line 141 at the start of the supply, but thereafter, the supply becomes gentle by the one-way orifice 78. The engagement timing of the 3-4 clutch 43 is adjusted. Reference numeral 92 denotes a duty solenoid valve, and 93 denotes an accumulator.

Further, the 2-3 timing valve 102 includes a 3-4
It is provided at the communication part between the line 127 led from the shift valve 65 and the servo release line 128, and the spool 1
The hydraulic pressure in the 3-4 clutch line 125 (that is, the 3-4 clutch pressure) is introduced to one end of 02a, and the servo release pressure is introduced to the other end. And
The servo release line 128 is communicated with 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 adjusted in accordance with the 3-4 clutch pressure.

Further, the 3-2 timing valve 103 spans 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 in the forward clutch line 119. It is provided. A pilot line 145 branched from a line 118 leading to the main line 110 is connected to one end of the spool 103a of the timing valve 103.
A drain line 146 branched from the servo release line 128 is connected to an intermediate portion of 03a, and a 3-2 solenoid valve 95 is attached to the pilot line 145. The timing valve 103 is connected to the 3-2.
By operating the solenoid valve 95, the first and second bypass lines 143, 143,
The opening and closing of 144 is performed to control the supply and discharge timing of the hydraulic pressure during these shifts. That is, at the time of the 1-2 shift-up shift, first, the first bypass line 143 is communicated to quickly supply the servo apply pressure to the apply port 45a 'of the servo piston 45', and a predetermined time from the start of the shift during the shift. By interrupting the first bypass line 143 when the elapsed time, in the second half of the shifting operation, the servo apply pressure is reduced by the one-way orifice.
Apply port 45a 'of servo piston 45' through 74
Supply slowly. At the time of the 3-2 downshift, the drain line 146 is first communicated with the drain port at the start of the shift, and thereafter, the drain line 146 is shut off. Therefore, the servo release pressure is quickly discharged through the drain line 146 in the first half of the shift operation, and is gradually discharged in the second half by the one-way orifice 81 that performs a throttle action in the discharge direction on the servo release line 128. . Further, at the time of the 4-2 downshift, firstly, 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 second bypass line 144 is opened. By cutting off the bypass line 144, the forward clutch is actuated by the throttling action of the one-way orifice 71.
Slowly supply forward clutch pressure to 41.

On the other hand, a main line 110 is connected to the back pressure ports 72a, 75a, 79a, 85a in the accumulators 72, 75, 79, 85, and the accumulators 72, 75, and 85 are hydraulically supplied from the main line I10. The shelf pressure forming state at 79 and 85 is to be controlled. The main line 110 is provided with a pressure regulating valve 91 having the pressure reducing valve 90 and the duty solenoid valve 92. When the duty solenoid valve 92 is ON, the main line
It drains 110 and acts to leak back pressure acting on each of the accumulators 72, 75, 79, 85, and is periodically opened and closed (in other words, ON / OFF) control. Therefore, the back pressure supplied from the main line 110 is controlled according to the duty ratio of the duty solenoid valve 92 (valve opening time ratio in one cycle).

As shown in FIG. 1, when the manual valve 62 is operated in the low speed range, the 1-2, 2-3 and 3-4 solenoid valves 66, 6 are provided to the hydraulic control circuit 60 configured as described above.
A control means 47 for controlling the opening and closing of the duty solenoid valves 68 and for controlling the duty of the duty solenoid valve 92 is additionally provided.

The control means 47 is composed of, for example, a microcomputer, and includes a shift speed detecting means 48 for detecting the range signal Rg (t) of the manual valve 62, a shift signal detecting means 49 for detecting the shift signal H, and a vehicle speed V of the vehicle. Receiving information from the vehicle speed detecting means 50 for detecting and the oil temperature detecting means 51 for detecting the oil temperature, an open / close command is issued to the 1-2, 2-3 and 3-4 solenoid valves 66, 67, 68, A duty control command is issued to the duty solenoid valve 92. That is, in the case of the present embodiment, the pressure reducing valve 90,
The pressure regulating valve 91, the duty solenoid valve 92, and the control means 47 constitute a back pressure control means in the claims. In the case of this embodiment, the above-mentioned 1-2, 2-3 and 3-4 solenoid valves are used.
66, 67 and 68 are SOL patterns (1) and
Opening / closing is controlled by (2).

Next, referring to the flowchart shown in FIG.
The control in the range will be specifically described.

During driving of the vehicle, the control unit 47 receives a range signal Rg (t), a shift signal H, a vehicle speed V, and an oil temperature T from the shift speed detecting unit 48, the shift signal detecting unit 49, the vehicle speed detecting unit 50, and the oil temperature detecting unit 51. Is input at any time (step S ₁ ). When the above information is input, the control by the control means 47 is stepped.
Advances to S _2, the range signal Rg (t), it is determined whether or not a 1 range, or if it is determined that Rg (t) = 1 is a shift signal H 1 speed in step S ₃ It is determined whether or not. When it is determined that H = "1" in step S _3, the process proceeds to step S _4, the corresponding to the vehicle speed V 5
Duty ratio D (V) read from the map shown in the figure
, Duty control for the duty solenoid valve 92 is performed. Therefore, the back pressure of the NR accumulator 85 is controlled according to the vehicle speed,
The accumulator shelf pressure is formed in an optimal state. Thereafter, the control by the control unit 47 proceeds to step S _5, the solenoid valves 66, 67 and 68, SOL pattern (1)
After the opening and closing control is performed for a predetermined time t (T) in the state shown by,
The process proceeds to step S _6, are opened and closed controlled to the state shown by the SOL pattern (2). The time t (T) is calculated as a function determined by the oil temperature T, and is read from the map shown in FIG. That is, when the oil temperature T is low (ie, when the viscosity of the oil is high), the time t (T) is long,
When the oil temperature T is high (that is, when the viscosity of the oil is low), the time t (T) is determined to be short. Accordingly, since the solenoid valves 66, 67, 68 are set to the state shown by the SOL pattern (1),
A bypass circuit 131 for bypassing the oil pressure is connected, and the time t (T) during which the hydraulic pressure supply to the low reverse brake 46 is promptly performed via the bypass circuit 131 is determined according to the viscosity of the oil. This allows N
The shelf pressure can be quickly formed by the -R accumulator 85. By the subsequent shift of the solenoid valves 66, 67, 68 to the SOL pattern (2), the supply of hydraulic pressure to the low reverse brake 46 is performed gently via the one-way orifice 84. Thereafter, the determination of the shift signal H is made in step S _7, H
= Solenoid valves 66, 67, 68 while "1" is determined
Hold the state of the SOL pattern (2). When it is determined that H ≠ "1" in step S7, the normal SOL control (i.e., ON · OFF control shown in Table 2) is made (step S _9).

As described above, according to the present embodiment, during high-speed traveling, when the manual valve 62 is shifted to one range and the automatic transmission shifts to the first speed, at the initial stage of engagement of the low reverse brake 46, The shelf pressure formation is accelerated by the rapid hydraulic pressure supply via the bypass circuit 131, and the low reverse brake 46 is then tightened by the gentle hydraulic pressure supply via the one-way orifice 84, and the low reverse brake Since the back pressure of the NR accumulator 85 for buffering the shift shock at the time of the engagement of 46 is to be controlled in accordance with the vehicle speed by the action of the back pressure control means, an optimum state corresponding to the vehicle speed is provided. Thus, the accumulator shelf pressure can be formed.

In the above embodiment, the opening and closing of the bypass circuit 131 is generally performed by the 3-4 shift valve 65. However, the opening and closing of the bypass circuit 131 may be performed by the 2-3 shift valve 64.

The present invention is not limited to the configuration of the above embodiment, and it is needless to say that the design can be appropriately changed without departing from the gist of the invention.

[Brief description of the drawings]

1 is an enlarged view of a main part of a hydraulic control circuit in a control device for an automatic transmission according to an embodiment of the present invention, FIG. 2 is a skeleton diagram showing a mechanical configuration of the automatic transmission according to the embodiment of the present invention, FIG. 3 is a hydraulic control circuit diagram in the control device of the automatic transmission according to the embodiment of the present invention, FIG. 4 is a flowchart for explaining the operation of the control device of the automatic transmission according to the embodiment of the present invention, FIG. 5 is a map for reading a duty ratio D (V) obtained as a function of the vehicle speed V, and FIG.
The figure is a map for calculating the holding time of the SOL pattern (1) from the oil temperature in the control device for the automatic transmission according to the embodiment of the present invention. 10 automatic transmission 30 transmission 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 control circuit 62: Manual valve 63: 1-2 shift Valve 64: 2-3 shift valve 65: 3-4 shift valve 66: 1-2 solenoid valve 67: 2-3 solenoid valve 68: 3-4 solenoid valve 84: Orifice for accumulator (one-way orifice ) 85… NR accumulator 90… Pressure reducing valve 91 …… Pressure regulating valve 92 …… Duty solenoid valve 110 …… Main line 130 …… Low reverse braker In 131 …… Bypass circuit

Continuation of front page (56) References JP-A-1-303349 (JP, A) JP-A-61-149657 (JP, A) JP-A-2-209662 (JP, A) JP-A-2-203066 (JP) JP-A-62-255645 (JP, A) JP-A-2-212665 (JP, A) JP-A-1-303349 (JP, A) JP-A-61-116164 (JP, A) 63-186055 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (2)

(57) [Claims] A transmission gear mechanism; a plurality of friction engagement elements for switching a power transmission path of the transmission gear mechanism; and a hydraulic control circuit for controlling supply / discharge of operating hydraulic pressure to / from a hydraulic actuator of the friction engagement elements. And a control device for the automatic transmission set to switch the engagement state of a plurality of specific frictional engagement elements among the frictional engagement elements at a predetermined gear shift, wherein the first gear of a low speed range in the hydraulic control circuit is A common accumulator is provided in the oil passage leading to the low reverse brake to be engaged when the reverse range is selected, for buffering the engaging pressure when the first reverse speed in the low speed range or when the low reverse brake is engaged when the reverse range is selected. Back pressure control means is provided for controlling the back pressure of the accumulator in accordance with the vehicle speed only when shifting to the first speed in the range. Control apparatus for an automatic transmission, characterized by being. 2. A bypass circuit for bypassing an accumulator orifice provided in an oil passage leading to the low reverse brake, a shift valve disposed in the middle of the bypass circuit, and opening and closing the shift valve by the bypass circuit. 2. The control device for an automatic transmission according to claim 1, further comprising a solenoid valve that is operated to operate the automatic transmission.