JP2981911B2 - 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 control device for a case where a shift lever is erroneously operated to a reverse range (hereinafter referred to as an R range) during high-speed running. The present invention relates to a control device for an automatic transmission that operates to prevent the automatic transmission from being in a reverse engagement state.

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, even if the automatic transmission is in a forward running state at a predetermined speed, when the shift lever is operated to the R range, the automatic transmission is in a reverse engagement state, and abrupt engine braking is applied. Affects the transmission. Therefore, a method for preventing the automatic transmission from being in the reverse engagement state even when the shift lever is erroneously operated to the R range has been considered.

For example, as disclosed in Japanese Unexamined Patent Publication No. 63-13949, the reverse engagement of an automatic transmission during high-speed running is achieved by using two shift valves and a solenoid valve that drives these shift valves. There have been proposals for preventing such problems.

(Problems to be Solved by the Invention) In the case of the above-mentioned known example, since the two shift valves and the solenoid valve are configured to be controlled, the circuit configuration is complicated and the control itself is not complicated. This not only increases the cost but also hinders downsizing.

The present invention has been made in view of the above-described points, and uses extremely simple means and control to perform shifting in a low-speed range,
It is an object of the present invention to achieve reverse engagement prohibition of the automatic transmission during high-speed traveling.

(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 a low reverse brake that is engaged when a shift speed of the friction engagement elements is in a low speed range of a low speed range and in a reverse range, and a manual valve in the hydraulic control circuit. A low-speed range circuit and a reverse range circuit of the ball valve that act to selectively connect the oil path to the low reverse brake. A low-speed range shift valve interposed in the oil passage from the switching valve to the low reverse brake;
A low-speed range solenoid valve that controls the supply of hydraulic pressure to the low reverse brake by controlling a pilot pressure introduced into the low-speed range shift valve, and a low-speed range solenoid valve according to the speed of the low-speed range. Outputting a control signal and a signal for stopping the supply of hydraulic pressure to the low reverse brake to the low speed range solenoid valve when the vehicle speed is equal to or higher than a predetermined value and the manual valve is switched to the reverse range. And control means for outputting

According to a second aspect of the present invention, in the control device for an automatic transmission according to the first aspect of the present invention, in order to solve the above-mentioned problem, the automatic transmission is further provided in an oil passage between the low-speed range shift valve and the low reverse brake. A bypass circuit for bypassing the accumulator orifice, another shift valve interposed in the bypass circuit, and a solenoid valve for operating the shift valve to open and close the bypass circuit are additionally provided.

(Operation) According to the first aspect of the present invention, the following effects can be obtained by the above means.

That is, when the low-speed range circuit of the manual valve is connected to the low reverse brake by the operation of the switching valve composed of the ball valve, the low-speed range solenoid valve is controlled to open and close to operate in the low-speed range (hereinafter referred to as one range). When the reverse range circuit of the manual halve is connected to the low reverse brake by the operation of the switching valve, when the vehicle speed is equal to or higher than a predetermined value, the solenoid valve for the low speed range is operated. In response, a signal is output from the control means, and the supply of hydraulic pressure to the low reverse brake via the low-speed range shift valve is stopped. Therefore, reverse engagement of the automatic transmission during high-speed running is prohibited.

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 the R range or the 1 range, the bypass that bypasses the accumulator orifice provided in the oil passage between the low speed range shift valve and the low reverse brake. By the switching operation of another shift valve provided in the middle of the circuit, at the beginning of the low reverse brake engagement, hydraulic pressure supply to the low reverse brake is promptly performed via the bypass circuit,
A quick pressure increase up to the accumulator shelf pressure is obtained,
Thereafter, with the closing of the bypass circuit, 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 the frictional engagement elements of the automatic transmission set to switch the engagement state of a plurality of specific frictional engagement elements among the frictional engagement elements during a predetermined gear shift. The low reverse brake, which is engaged when the shift speed is in the low speed range of the low speed range and in the reverse range, and the low speed range circuit and the reverse range circuit of the manual valve in the hydraulic control circuit selectively reach the low reverse brake. A switching valve consisting of a ball valve acting so as to be connected to an oil passage is provided, and between the switching valve and the low reverse brake; In the middle of the oil passage, a low-speed range shift valve and a low-speed range solenoid valve that controls the supply of hydraulic pressure to the low reverse brake by reducing pilot pressure introduced to the low-speed range shift valve to drain. In addition to providing a signal for controlling the low-speed range solenoid valve according to the shift speed of the low-speed range, when the vehicle speed is equal to or higher than a predetermined value and the manual valve is switched to the reverse range, A control means for outputting an open signal to the low-speed range solenoid valve is provided, and when the low-speed range circuit of the manual valve is connected to the low reverse brake by the operation of the switching valve, the low-speed range solenoid valve is provided. Opening and closing control so that a shift in one range can be performed and the operation of the switching valve When the reverse range circuit of the manual valve is connected to the low reverse brake, when the vehicle speed is higher than a predetermined value, the low speed range solenoid valve is opened by a command from the control means to open the low speed range solenoid valve. Since the supply of hydraulic pressure to the low-reverse brake via the shift valve can be stopped, a very simple circuit configuration and control using one switching valve and one shift valve enables control over one range. There is an excellent effect that it is possible to achieve shifting and prohibiting reverse engagement of the automatic transmission during shifting traveling.

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 between a low-speed range shift valve and a low-reverse brake is provided. At the same time, a low reverse brake is engaged when the manual valve is operated in the R range or one range by interposing another shift valve and a solenoid valve for opening and closing the shift valve in the middle of the bypass circuit. At times, the switching operation of other shift valves causes
At the beginning of the low reverse brake engagement, hydraulic pressure is supplied to the low reverse brake via the bypass circuit, and a rapid pressure increase up to the accumulator shelf pressure can be obtained. Since the low reverse brake is engaged by supplying hydraulic pressure through the orifice for the accumulator, the reverse engagement or forward engagement of the automatic transmission during the R range operation or the one range operation of the manual valve (that is, the forward engagement) , Low reverse brake engaged)
Has an excellent effect that it can be performed quickly and reliably.

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, 1, R as a driving range, the 1st to 4th speed in the D range, and 2
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 pump 22.
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 an operating device.

The relationship between the operating state 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 publicly known, and therefore detailed description is omitted 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 being supplied to both ports 45a 'and 45b' and when the hydraulic pressure is being supplied to both 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 shift valves 63, 64, and 65 for supplying and discharging hydraulic pressure to and from the friction engagement elements (actuators) 41 to 46, respectively.
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. Then, the pilot port 63 of the 1-2 shift valve 63
A pilot line 115 branched from the main line 110 via a line 118 is connected to b,
The pilot line 116 branched from the first output line 111 is connected to the pilot port 64b of the shift valve 64, and the pilot port 65b of the 3-4 shift valve 65 is connected to the pilot port 64b.
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, 68 are provided. These solenoid valves 66 to 68 drain the pilot lines 115, 116, and 117 when they are in the ON state, and control the pilot ports 63b to 6 of the corresponding shift valves 63 to 65.
By discharging the pilot pressure in 5b, the spool 63
a to 65a are positioned on the right side of the drawing, while
In the F state, the pilot pressure is introduced into the pilot ports 63b to 65 from the pilot lines 115, 116, and 117, and the spools 63a to 65a are respectively positioned 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 to the forward clutch line 119 via the line 120 to act as a buffer for engaging the forward clutch. The D accumulator 72 is connected. 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, in the D, 2,1 range, the 1-2 solenoid valve 6
When 6 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, hydraulic pressure (ie, servo apply pressure) is applied to the apply port 45a '. ) Is introduced, and hydraulic pressure (ie, servo apply pressure) is not introduced into the release port 45b '(ie, 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.

In addition, the second, which communicates with the main line 110 in the D, 2 range
The output line 112 is led to the 2-3 shift valve 64. The second output line 112 communicates with the 3-4 clutch line 125 when the 2-3 solenoid valve 67 is in the OFF state and the spool 64a is located on the left side. The orifice 78 reaches the 3-4 clutch 43. Therefore, when the 2-3 solenoid valve 67 is in the OFF state in the D, 2 range,
The 3-4 clutch 43 is engaged at the third and fourth speeds of the range and the third speed of the second range. The 3-4 clutch line 125 is connected to a 2-3 accumulator 79 which functions as a buffer when the 3-4 clutch operates. Code 80
Is 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
And when the 3-4 solenoid valves 67 and 68 are both in the OFF state, 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 via a coast timing valve 82 and the ball valve 77.
It leads to 124 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.

A third output line 113 communicating with the main line 110 in one range by the manual valve 62 is led to a 1-2 shift valve 63 via a ball valve 83 acting as a switching valve, and a 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 acting as an accumulator orifice. Therefore, when the 1-2 solenoid valve 66 is in the OFF state in the 18 range, that is, at the first speed in the 1 range, the low reverse brake 46 is engaged. 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 OFF and the spool 65a is located on the left side, the first and second branch paths 131a and 131b are to be 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. Reference numeral 96 denotes a one-way orifice.

Main line 11 with R range of manual valve 62
The fourth output line 114 communicating with 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.

A torque converter line 134 is guided from the regulator valve 61 to the lock-up shift valve 86, 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
-2 attached to the timing valve 103.

As described above, the coast timing valve 82 is provided on a line 129 branched from the servo release line 128 and communicating 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 21. 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, at the time of the 2-3 shift up shift of the D range and the 2 range where the coast clutch pressure is supplied to the coast clutch 42 via the line 129,
After the servo release pressure has sufficiently increased (that is, after the 2-4 brake 45 has been securely released), the coast clutch 42
Are connected, so that the 2-4 brake 45 and the coast clutch 42 are simultaneously engaged to prevent the double lock. Since the servo apply pressure is guided to one end of the spool 82a 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 applied to 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 101a moves to the left, the bypass line 141
Is to be shut 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 is moderated by the one-way orifice 78. , The engagement timing of the 34 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.

The 3-2 timing valve 103 straddles 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. And the spool 1 of the 3-2 timing valve 103
A pilot line 145 branched from a line 118 leading to the main line 110 is connected to one end of the spool 103a, and a servo release line 128 is provided at an intermediate portion of the spool 103a.
A drain line 146 is connected to the pilot line 145, and a 3-2 solenoid valve 9 is connected to the pilot line 145.
5 is attached. This 3-2 timing valve 103
Is operated by the operation of the 3-2 solenoid valve 95.
The first and second bypass lines 143 and 144 are opened / closed at the time of 2-shift upshift, 3-2 shift-down conversion, and 4-2 shift-down shift to control supply / discharge timing of hydraulic pressure during these shifts. I do. That is, 1
At the time of -2 shift up shift, first, the first bypass line
143, and apply servo apply pressure to servo piston 4
By supplying the fluid to the 5 'apply port 45a' promptly and cutting off the first bypass line 143 when a predetermined time has elapsed from the start of the gear shift during the gear shift, the servo apply pressure is set in the latter half of the gear shift operation. Through the one-way orifice 74 to the apply port 45a 'of the servo piston 45'. Also, at the time of a 3-2 downshift, at the start of the shift, first the drain line
146 is communicated with the drain port, and then 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 interrupting the bypass line 144, the forward clutch pressure is gradually supplied to the forward clutch 41 by the throttle action of the one-way orifice 71.

As shown in FIG. 1, when the manual valve 62 is operated in the R range, the 1-2, 2-3 and 3-4 solenoid valves 66, 67,
A control means 47 for controlling the opening and closing of 68 is provided.

The control means 47 is composed of, for example, a microcomputer, and includes a gear position detection means 48 for detecting the range signal Rg (t) of the manual valve 62, a vehicle speed detection means 49 for detecting the vehicle speed V of the vehicle, and a hydraulic control circuit 60. Upon receiving information from the oil temperature detecting means 50 for detecting the oil temperature T,
It issues an opening / closing command to the 2, 2-3 and 3-4 solenoid valves 66, 67, 68. In the case of this embodiment, the above-mentioned 1-2, 2-3 and 3-4 solenoid valves are used.
66, 67, 68 are SOL patterns (1) shown in Table 3 below,
Opening and closing are controlled by (2) and (3).

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

During motoring, gear position detecting means 48 to the control unit 47, a range signal from the vehicle speed detecting means 49 and the oil temperature detecting means 50 Rg (t), the vehicle speed V and fluid temperature T is inputted from time to time (Step S ₁₎ . When the above information is input, the control means 47
Control proceeds to step S ₂ by, the range signal Rg (t) is whether the R-range is determined. And step
When the S ₂ is determined to Rg (t) = "R", the process proceeds to step S _3, compared with the set value V ₀ and the vehicle speed V is performed.
Here, when it is determined that V ≧ V ₀ (i.e., if the motor vehicle is in a high speed running), the process proceeds to step S _4, the solenoid valves 66, 67 and 68, SOL by a command from the control unit 47
Opening / closing is controlled in the state shown by the pattern (1). Therefore,
As a result of the spool 63a of the 1-2 shift valve 63 being located on the right side, the reverse clutch pressure guided through the fourth output line 114, the line 132 and the ball valve 83 becomes
It is no longer supplied to the low reverse brake line 130,
The low reverse brake 46 cannot be engaged. That is, even if the manual valve 62 is operated in the R range,
When the vehicle is running at a set value greater than or equal _to V ₀ of the speed,
As a result, reverse engagement of the automatic transmission is prohibited. Thereafter, at step S ₅ the range signal Rg (t)
Is determined, and while Rg (t) = “R” is determined, the solenoid valves 66, 67, and 68 maintain the state of the SOL pattern (1). Then, Rg (t) in step S ₅ ≠
If it is determined that "R" is normal SOL control (i.e., ON · OFF control shown in Table 2) is made (step S _6).
On the other hand, V <V ₀ in step S ₃ (i.e., an automobile is not in high-speed running) When it is determined that the control of the control unit 47 proceeds to step S _7, the solenoid valves 66, 67, 68
Is a predetermined time t (T) in the state shown by the SOL pattern (2).
After being only close control, the process proceeds to step S _8, is opened and closed controlled to the state shown by the SOL pattern (3). 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 (that is, when the year of the oil is high), the time t (T) is long, and when the oil temperature T is high (that is, when the oil temperature T is high)
(When the viscosity of the oil is low), the time t (T) is determined to be short. Therefore, the solenoid valve 6
By setting the state of 6, 67, 68 to the state shown by the SOL pattern (2), the bypass circuit 131 for bypassing the one-way orifice 84 is connected, and the supply of hydraulic pressure to the low reverse brake 46 is promptly performed via the bypass circuit 131. Is determined in accordance with the viscosity of the oil. As a result, the shelf pressure can be quickly formed by the NR accumulator 85. After that, the solenoid valves 66, 67, 68
Due to the shift to the SOL pattern (3), the supply of hydraulic pressure to the low reverse brake 46 is performed gently via the one-way orifice 84. Thereafter, the determination of range signal Rg (t) is made in step S _9, the solenoid valve 66, 67 and 68 while it is determined that Rg (t) = "R" is holding the state of the SOL pattern (3) Is done. And step S ₉
When it is determined that Rg (t) ≠ “R” at
SOL control (i.e., ON · OFF control shown in Table 2) is made (step S _6).

As described above, according to this embodiment, when the manual valve 62 is operated to the R range during high-speed traveling, the reverse engagement of the automatic transmission is prohibited, and when the vehicle is not traveling at high speed, the automatic transmission is prohibited. , Low reverse brake 46
In the initial stage of the engagement, the shelf pressure formation is accelerated by the rapid hydraulic supply via the bypass circuit 131, and the low reverse brake 46 is engaged by the gradual hydraulic supply via the one-way orifice 84 thereafter. .

In the above embodiment, the opening and closing of the bypass circuit 131 is performed by the 3-4 shift valve 65. However, the opening and closing of the bypass circuit 131 is performed by a 2-3 shift valve other than the 1-2 shift valve 63. In some cases, the adjustment is performed by the 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 calculating the holding time of the SOL pattern (2) 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 83: Switching valve (ball valve) 84: Orifice for accumulator (one-way orifice) 113: Low-speed range circuit 114: Reverse range circuit 131: Bypass circuit

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. A control device for an 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 a shift speed of the frictional engagement element is A low reverse brake that is engaged when in the low speed range of the low speed range and in the reverse range, and a low speed range circuit and a reverse range circuit of a manual valve in the hydraulic control circuit are selectively connected to an oil path leading to the low reverse brake. A switching valve composed of a ball valve acting so as to be connected, and a switching valve in the middle of an oil passage from the switching valve to the low reverse brake. A low-speed range shift valve, a low-speed range solenoid valve that controls hydraulic pressure supply to the low reverse brake by controlling pilot pressure introduced to the low-speed range shift valve, and a low-speed range shift stage. And outputting a signal for controlling the low-speed range solenoid valve in response to the low-speed range solenoid valve when the vehicle speed is higher than a predetermined value and the manual valve is switched to the reverse range. Control means for outputting a signal to stop supplying hydraulic pressure to the automatic transmission. 2. A bypass circuit for bypassing an accumulator orifice provided in an oil passage between the low-speed range shift valve and the low reverse brake, and another shift valve provided in the middle of the bypass circuit. 2. A control device for an automatic transmission according to claim 1, further comprising a solenoid valve for operating said shift valve to open and close said bypass circuit.