JPH06201037A - Oil pressure control device for vehicular automatic transmission - Google Patents

Abstract

(57) [Abstract] [Purpose] Even when the shift lever is operated to the reverse range during low-speed forward travel, the reverse gear is established without causing shock due to engagement of the reverse hydraulic friction engagement device. A hydraulic control device for an automatic transmission for a vehicle is provided. [Structure] The source pressure drop detecting means 100 allows the hydraulic pump 5
If the original pressure output from 6 is detected state decreases, because its source pressure is increased to the rotation speed N _e of the engine 10 is raised by the original pressure increasing device 102, a relatively low speed Shift lever 96 during forward running
Even if the discharge capacity of the hydraulic pump 56 is likely to be insufficient due to the operation to the R range, the engine rotation speed N _e is increased and the discharge capacity of the hydraulic pump 56 is increased. The decrease reliably prevents the occurrence of shock due to the temporary engagement of the reverse hydraulic frictional engagement device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control system for an automatic transmission for a vehicle, and more particularly to a disadvantage caused by a reduction in the original pressure when the shift lever is operated to the reverse range while the vehicle is moving forward. It is related to the technology to resolve.

[0002]

2. Description of the Related Art In an automatic transmission for a vehicle which establishes a forward gear stage or a reverse gear stage in accordance with the operation of a forward or reverse hydraulic friction engagement device, the hydraulic friction engagement of the vehicle is driven by rotation by an engine. The R range pressure supplied to the reverse hydraulic friction engagement device is changed from the original pressure based on the operation of the hydraulic pump that outputs the original pressure for operating the device and the shift lever to the reverse range. Open the oil passage between the switching valve to be generated, the reverse hydraulic frictional engagement device and the switching valve to allow the reverse gear to be established, and close the oil passage to establish the reverse gear. A reverse control valve that has a valve positioned in a closed position to prevent the valve from switching from the open position to the closed position when signal pressure is applied, and regardless of whether the vehicle is traveling forward. Serial shift lever when operated to the R range, the hydraulic control device and a signal pressure generation means which applies the signal pressure to said valve element is known. For example, the device described in Japanese Patent Laid-Open No. 2-89865 is that.

In the conventional hydraulic control device as described above, the reverse hydraulic friction engagement device is provided before the valve element of the reverse control valve moves to the closed position where the reverse gear is blocked by the action of the signal pressure. In order to cancel the engagement,
An orifice for delaying engagement of the reverse hydraulic friction engagement device by a predetermined time is provided in an oil passage extending from the reverse control valve to the reverse hydraulic friction engagement device. That is, when the original pressure (line pressure) is normal, the time required to switch the reverse control valve to the closed position is about 0.1 seconds, while the engagement of the reverse hydraulic friction engagement device by the orifice is performed. Since the time to start is set to about 0.3 to 0.4 seconds, the reverse control valve is surely switched to its closed position before the engagement of the reverse hydraulic friction engagement device is started, and the forward movement is advanced. Even if the shift lever is operated to the reverse range during traveling, the establishment of the reverse gear is reliably prevented.

[0004]

However, in the above hydraulic control device, when the shift lever is operated to the reverse range during forward traveling at a relatively low speed of, for example, about 20 to 30 km / h, the engine speed is reduced. Is 1100r.
Since it is less than pm and the discharge capacity of the hydraulic pump driven by the engine is not sufficient, operating oil is made to flow to the reverse hydraulic friction engagement device by operation to the reverse range and is consumed there. Relatedly, the source pressure output from the hydraulic pump and the signal pressure generated from it also decrease. For this reason, the operation of moving the valve element of the reverse control valve to the closed position that prevents the reverse gear stage from being established due to the action of the signal pressure is delayed, and shock due to temporary engagement of the reverse hydraulic friction engagement device is generated. There was an inconvenience. That is, the minimum pressure P _PM required to move the piston of the reverse hydraulic friction engagement device to the position where the engagement between the friction plates is generated, and the valve element of the reverse control valve to the closed position. Since there is a minimum signal pressure value P _CM required for the above, the pressure of the hydraulic oil supplied to the reverse hydraulic friction engagement device and the above signal pressure both decrease in association with the decrease in the source pressure. This is because the pressure of the hydraulic oil supplied to the reverse hydraulic friction engagement device reaches the minimum value P _PM before the signal pressure reaches the minimum value P _CM .

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a reverse hydraulic friction engagement even when a shift lever is operated to a reverse range during low speed forward traveling. An object of the present invention is to provide a hydraulic control device for an automatic transmission for a vehicle, which prevents a reverse gear from being established without causing a shock due to engagement of the device.

[0006]

To achieve the above object, the gist of the present invention is to establish a forward gear stage or a reverse gear stage in accordance with the operation of a forward or reverse hydraulic friction engagement device. In an automatic transmission for a vehicle, a hydraulic pump that outputs a source pressure for operating a hydraulic friction engagement device by being rotationally driven by an engine and a shift lever that is operated to a reverse range are used. , A switching valve for generating the R range pressure supplied to the reverse hydraulic friction engagement device from the original pressure, and an oil passage between the reverse hydraulic friction engagement device and the switching valve are opened to perform the reverse drive. It has a valve that is placed in an open position that allows the gear stage to be established and in a closed position that closes the oil passage to prevent the reverse gear stage from being established, and the valve opens when the signal pressure is applied. Switch from position to closed position And reverse control valve for recombination, the shift lever is R regardless of the traveling forward of the vehicle
A hydraulic control device comprising a signal pressure generating means for causing the signal pressure to act on the valve when operated to a range, wherein (a) an element for detecting a state where the original pressure is lower than a predetermined value. A pressure drop detection means, and (b) a source pressure increase means for increasing the source pressure by increasing the engine speed when the source pressure drop detection means detects a state where the source pressure decreases. Is included.

[0007]

With this configuration, when the source pressure drop detecting means detects the state where the source pressure drops, the source pressure raising means raises the engine rotational speed to raise the source pressure. .

[0008]

Therefore, according to the present invention, when the shift lever is operated to the reverse range during the forward traveling at a relatively low speed, the source pressure output from the hydraulic pump decreases, and the source pressure rises. Since the original pressure is increased by the means, the reverse control valve is switched to the closed position before the engagement of the reverse hydraulic friction engagement device is started. The occurrence of shock due to the temporary engagement of the device is reliably prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an automatic transmission for a vehicle to which an embodiment of the present invention is applied and a control device therefor. In the figure, the power of the engine 10 is transmitted to the drive wheels via a torque converter 12 with a lockup clutch 12, a stepped automatic transmission 14 including three sets of planetary gear units, and a differential gear device (not shown). It has become so.

The torque converter 12 is the engine 1
Pump impeller 18 connected to zero crankshaft 16
And a turbine impeller 22 fixed to the input shaft 20 of the automatic transmission 14 and rotated by receiving oil from the pump impeller 18, and a housing 26 which is a non-rotating member via a one-way clutch 24. Stator wheel 28
And a lockup clutch 32 connected to the input shaft 20 via a damper 30. When the oil pressure in the disengagement side oil chamber 33 is higher than the oil pressure in the engagement side oil chamber 35 in the torque converter 12, the lockup clutch 32 is disengaged, so that the input / output rotation speed ratio of the torque converter 12 is reduced. The torque is transmitted at a corresponding amplification factor. However, when the hydraulic pressure in the engagement-side oil chamber 35 is higher than that in the disengagement-side oil chamber 33, the lockup clutch 32 is brought into the engaged state, so that the input / output members of the torque converter 12, that is, the crankshaft 16 and the input. The shaft 20 is directly connected.

The automatic transmission 14 has three coaxially arranged parts.
Set of single pinion type planetary gear units 34, 36, 38
And an input shaft 20, an output gear 39 that rotates together with a ring gear of the planetary gear device 38, and a counter shaft (output shaft) 40 that transmits power between the differential gear device. Some of the components of the planetary gear units 34, 36 and 38 are not only integrally connected to each other, but also selectively connected to each other by three clutches C ₀ , C ₁ and C ₂ . Further, the planetary gear units 34, 36, 3
Some of the eight components are four brakes B ₀ , B ₁ , B
₂ and B ₃ are selectively connected to the housing 26, and further, some of the components are engaged with each other or with the housing 26 by their rotational directions by three one-way clutches F ₀ , F ₁ and F ₂ . It is supposed to be done.

Each of the clutches C ₀ , C ₁ and C ₂ and the brakes B ₀ , B ₁ , B ₂ and B ₃ is provided with, for example, a multi-plate type clutch or one band or two bands whose winding directions are opposite to each other. 2 is a hydraulic friction engagement device including band brakes and the like, which is operated by hydraulic actuators, and the operation of the hydraulic actuators is controlled by an electronic control unit 42, which will be described later.
As shown in (4), it is possible to obtain four forward gears and one reverse gear with different gear ratios I (= rotational speed of input shaft 20 / rotational speed of counter shaft 40). In FIG.
“1st”, “2nd”, “3rd”, and “O / D (overdrive)” are the forward first gear, second gear, third gear, and fourth gear, respectively. The gear ratio gradually decreases from the first gear to the fourth gear. Since the torque converter 12 and the automatic transmission 14 are configured symmetrically with respect to the axis, the lower side of the rotation axis of the input shaft 20 and the upper side of the rotation axis of the counter shaft 40 are shown in FIG. It is omitted.

The hydraulic control circuit 44 includes a shift control hydraulic control circuit for controlling the gear stage of the automatic transmission 14 and an engagement control hydraulic pressure for controlling the engagement of the lockup clutch 32. And a control circuit. As is well known, the hydraulic control circuit for gear shift control includes a first solenoid valve 46 and a second solenoid valve 48 that are turned on and off by solenoid No. 1 and solenoid No. 2, respectively. Valve 46 and second solenoid valve 4
As shown in FIG. 2, the combination of the operations of No. 8 selectively activates the clutch and the brake to establish any one of the first to fourth speed gear stages. A circle mark in FIG. 2 indicates an on state or an engaged state.

The engagement control hydraulic control circuit is turned on / off by a switching electromagnetic solenoid to generate a switching signal pressure, and a clutch switching valve (not shown) is brought into a lockup clutch released state and a lockup clutch engagement state. A third solenoid valve 50 positioned in the combined state and a reverse drive solenoid valve 54 that generates a signal pressure P _IH for blocking the establishment of the reverse gear is based on a solenoid modulator pressure described later.

In FIG. 3, the hydraulic oil pumped from the hydraulic pump 56 rotationally driven by the engine 10 corresponds to the throttle pressure output from a throttle valve opening detection valve (not shown) by an overflow type pressure regulating valve 58. The line pressure P1 is adjusted to a predetermined value by the action of the reverse range pressure P _R. This line pressure P1 is a manual valve 60 that is switched according to the operation of a shift lever 96 described later, a solenoid modulator valve 62 that outputs a constant solenoid modulator pressure regardless of fluctuations in the line pressure P1, and a 3-4 shift valve 64. , The first solenoid valve 46, and the second solenoid valve 48. In the manual valve 60, the shift lever 96 has D, S, L
When operated in the range position, the D range pressure P _D is generated, when the shift lever 96 is operated in the L range position, S range pressure P _S is generated, and the shift lever 96 is operated in the L range position. L when
Generates range pressure P _L. Those D range pressures P _D , S
The range pressure P _S and the L range pressure P _L are supplied to the 1-2 shift valve 66 and the 2-3 shift valve 68 for operating the hydraulic friction engagement devices. Therefore, the hydraulic pump 5
The line hydraulic pressure P1 output from 6 and regulated is the source pressure for operating each hydraulic friction engagement device, and the source pressure of the signal pressure P _IH for preventing the establishment of the reverse gear. But also.

The 1-2 shift valve 66 is the second solenoid valve 48.
Are switched by the first solenoid valve 46, and the 3-4 shift valve 64 is switched by the second solenoid valve 48 and the 2-3 shift valve 68. In FIG. 3, the 1-2 shift valve 66,
On the left and right sides of the center line of the spool valve element of the 2-3 shift valve 68 and the 3-4 shift valve 64, reference numerals indicating gear stages and operating positions for establishing the gear stages are respectively shown.

Therefore, when the shift lever 96 is operated to the forward (D, S, L) range, the clutch C1 is engaged by supplying the D range pressure P _D. When the first speed gear stage is established in this state, the first solenoid valve 46 is turned on and the second solenoid valve 48 is turned off, so that each shift valve 6
Since the spool valve elements of Nos. 4, 66, and 68 are located on the side labeled "1" indicating the first gear in FIG. 3, the clutches C0 and C1 are engaged. Also,
When the second speed gear is established, both the first solenoid valve 46 and the second solenoid valve 48 are turned on, so that the spool valve elements of the shift valves 64, 66, 68 are arranged as shown in FIG.
, The clutch C0, C1 and the brake B are located on the side marked with "2" indicating the second gear.
2 are engaged. In this embodiment, the clutch C1 is
Alternatively, the clutch C1 and the brake B2 correspond to the forward hydraulic friction engagement device.

When the reverse gear is established,
Since the shift lever 96 is operated to the reverse (R) range, the reverse range pressure P _R is generated instead of the D range pressure P _D and is supplied to the 2-3 shift valve 68 and the reverse control valve 70. . The reverse control valve 70 includes a spool valve 71 that opens and closes between the manual valve 60, the 1-2 shift valve 66 and the brake B3,
A spring 72 for urging the spool valve 71 in the valve opening direction.
When, an oil chamber 73 for receiving the D range pressure P _D is a holding pressure for biasing the spool 71 in the valve opening direction, the solenoid for reverse blocking for urging the spool 71 in the valve closing direction An oil chamber 74 for receiving the signal pressure P _IH from the valve 54, and the spool valve element 71 allows the reverse range pressure P _R to be supplied to the brake B3 in its open position, but in its closed position. It is configured to prevent the reverse range pressure P _{R from} being supplied to the brake B3 and drain the inside of the brake B3.

The reverse range pressure P _R is supplied to the clutch C2 at the same time as the spool valve _element is supplied to the clutch C2 through the 2-3 shift valve 68 located at the position shown on the left side of the center line.
It is also fed to the 1-2 shift valve 66 to position its spool valve element at the position shown to the left of its centerline. When the shift lever 96 is normally operated to the reverse (R) range while the vehicle is stopped, the signal pressure P _IH for preventing the establishment of the reverse gear is not generated, and the reverse control valve 7
Since the spool valve element 0 of 0 is located in the open position, the reverse range pressure P _R is applied to the brake B3 through the reverse control valve 70 and the 1-2 shift valve 66.
Is supplied to. As a result, the clutch C0 is engaged with the clutch C2 and the brake B3, and the reverse gear is established. The clutch C0 is a 3-4 shift valve 64.
Therefore, it is engaged in the case other than the O / D gear. In this embodiment, the clutch C2 and the brake B are
3 corresponds to a reverse hydraulic friction engagement device. A throttle SS1 for controlling the flow rate is provided in each oil passage through which the hydraulic oil is supplied to the clutch C2.

In FIG. 3, the low coast modulator valve 75 is a valve for controlling the L range pressure P _L supplied to the brake B3 when the fist lever is operated to the L range. Further, 76 is an S shift valve, 77
Is a B1 orifice control valve, and 78 is a second coast modulator valve.

Returning to FIG. 1, the electronic control unit 42 controls the CP
A so-called microcomputer including a U82, a ROM 84, a RAM 86, an interface (not shown), etc., for detecting the opening degree of a throttle valve 87 provided in the intake pipe of the engine 10 and opened / closed by operating an accelerator pedal (not shown). A throttle sensor 88, an engine rotation speed sensor 90 that detects the rotation speed of the engine 10, an input shaft rotation sensor 92 that detects the rotation speed of the input shaft 20 of the automatic transmission 14, and a rotation speed of the counter shaft 40 of the automatic transmission 14. Counter shaft rotation sensor 9 to detect
4, the operating position of the shift lever 96, that is, L, S,
From the operation position sensor 98 for detecting any one of the D, N, R, and P ranges, a signal indicating the throttle valve opening θ _th , engine rotation speed N _e (pump impeller rotation speed N _P ,
That is, the input side rotation speed of the lockup clutch 32)
Signal indicating the input shaft rotation speed N _in (turbine impeller rotation speed N _T , that is, output side rotation speed of the lockup clutch 32), output shaft rotation speed N _out , shift lever 96 operating position A signal representing P _s is supplied to each.

The CPU 82 of the electronic control unit 42 is R
The first solenoid valve 46 is used to process the input signal according to the program stored in advance in the ROM 84 while utilizing the temporary storage function of the AM 86 and to execute the shift control of the automatic transmission 14.
The second solenoid valve 48 is controlled, the third solenoid valve 50 is controlled to execute the engagement control of the lockup clutch 32, and the reverse travel prevention solenoid valve 54 is controlled for the reverse inhibit control.

In the above shift control, a shift diagram corresponding to an actual shift gear is selected from a plurality of types of shift diagrams stored in advance in the ROM 84, and the running state of the vehicle, for example, the throttle valve opening is selected from the shift diagram. The shift gear is determined based on the degree θ _th and the vehicle speed calculated from the output shaft rotation speed N _out, and the first solenoid valve 4 is provided so that the shift gear is obtained.
6. By driving the second solenoid valve 48, the clutches C ₀ , C ₁ , C ₂ and the brake B ₀ of the automatic transmission 14 are driven.
, B ₁ , B ₂ , and B ₃ are controlled to establish any of the four forward gears. In the engagement control of the lockup clutch 32, the ROM 8 is previously set.
Based on the traveling state of the vehicle, for example, the output shaft rotation speed (vehicle speed) N _out and the throttle valve opening degree θ _th , the release area, the slip control area, and the engagement of the lockup clutch 32 are stored from the relationship shown in FIG. It is determined which of the areas the lockup clutch 32 is in according to this determination.
Is controlled.

In the reverse inhibit control, the shift lever 96 is operated to the reverse range when the vehicle is traveling forward with the output shaft rotational speed N _out or the vehicle speed V calculated from the output shaft rotational speed N _out exceeding a predetermined judgment reference value. If it is detected, the reverse movement preventing solenoid valve 54 is switched to the ON state, so that the reverse movement preventing solenoid valve 5 is turned on.
The signal pressure P _IH for preventing the establishment of the reverse gear from 4 is generated, and the spool valve element of the reverse control valve 70 is positioned at the closed position shown on the left side of its center line. The reverse range pressure P _R supplied to the valve 70 is further prevented from being supplied to the brake B3 through the 2-3 shift valve 68, and the reverse gear stage is also prevented from being established.

FIG. 4 is a functional block diagram showing a main part of the reverse inhibit control of the electronic control unit 42. In the figure, when the source pressure drop detecting means 100 detects a state in which the source pressure output from the hydraulic pump 56 drops, the source pressure raising means 102 raises the rotation speed N _e of the engine 10, and The source pressure is increased.
Therefore, in a state in which the source pressure output from the hydraulic pump 56, that is, the line pressure P1 when the shift lever 96 is operated to the R range during the forward traveling at a relatively low speed, is reduced by the source pressure increasing means 102. Since the reverse control valve 70 is switched to the closed position before the engagement of the reverse hydraulic friction engagement device is started, the reverse hydraulic valve friction engagement device is temporarily stopped due to the decrease in the original pressure. The occurrence of a shock due to the positive engagement is reliably prevented.

Next, the reverse inhibit control operation of the electronic control unit 42 will be described with reference to the flowchart of FIG. In step SH1 of the routine of FIG. 5, it is determined whether the shift lever 96 has been operated to the R range.
If the determination in step SH1 is negative, this routine is ended and a main routine (not shown) is executed. However, if the determination in step SH1 is affirmative, it is determined in step SH2 whether the vehicle speed V is higher than a predetermined determination reference value V ₀ . This judgment reference value V ₀ corresponds to the upper limit value of the low vehicle speed range that does not require the reverse gear stage to be prevented from being established, and a value of about 10 km / h is adopted, for example.

If the determination in step SH2 is negative, the reverse inhibit control is not necessary and this routine is ended. However, the above step SH2
If the determination is affirmative, in step SH3, the reverse travel preventing solenoid valve 54 is turned on, the signal pressure P _IH is supplied to the oil chamber 74, and the spool valve 71 of the reverse control valve 70 is in its open position. Tries to switch to the closed position against the biasing force of the spring 72.

In the following step SH4, the shift lever 9
It is determined whether the time T _N during which 6 has been operated in the N range is smaller than a predetermined determination reference value T ₀ . When the shift lever 96 is held in the N range, the D range pressure P _D, which is the holding pressure, in the oil chamber 73 of the reverse control valve 70 is reduced to the atmospheric pressure. Since the state can be swiftly switched to the closed position, the judgment reference value T ₀ is such that the spool valve 71 can be swiftly switched to the closed position by operating the pressure in the oil chamber 73 to the N range. It is set to a value that corresponds to the time required to drop to a sufficiently low value.

If the determination in step SH4 is negative, the spool valve 7 of the reverse control valve 70
1 is in a state in which it can be quickly switched to the closed position, and it is not necessary to temporarily increase the line pressure P1 which is the output pressure of the hydraulic pump 56, so this routine is ended. However, if the determination in step SH4 is positive,
In the following step SH5, it is determined whether the engine rotation speed N _e is smaller than a predetermined determination reference value N _e0 . This judgment reference value N _e0 is such that when the shift lever 96 is operated from the forward range to the R range, the line pressure P1 which is the output pressure of the hydraulic pump 56 rotationally driven by the engine 10 is the discharge capacity of the hydraulic pump 56. Is a value corresponding to the engine rotation speed N _e which is reduced due to the lack of the pressure regulating valve 58, for example, 1100 rpm.
The value of the degree is adopted. In this embodiment, the above step S
H5 corresponds to the source pressure drop detecting means 100 that detects a state where the source pressure, which is the line pressure P1, is reduced.

If the determination in step SH5 is negative, control for temporarily increasing the source pressure is unnecessary, so this routine is ended. However, if the determination in step SH5 is affirmative, in step SH6 corresponding to the source pressure increasing means 102, the engine speed for increasing the discharge capacity of the hydraulic pump 56 to prevent the line pressure P1 from decreasing. The rising control is executed and this routine is ended. In this step SH6, for example, in idle speed control (ISC control) executed by the engine electronic control unit 110, the throttle valve is adjusted so that the actual engine speed N _e matches the target idle speed N _e ^T. The ISC valve in the bypass passage (not shown) provided in parallel with 87 is operated, but in step SH6, the target rotation speed N _e is reached.
^T the output therefrom to a signal for temporarily changing the predetermined value higher value N _e ^T + alpha than the value the electronic control unit 42 to the engine electronic control unit 110, the engine rotational speed as shown in FIG. 6 At the same time that N _e is temporarily controlled to increase, the discharge capacity of the hydraulic pump 56 is also temporarily increased to prevent the line pressure P1 from decreasing. In the engine electronic control unit 110 of this embodiment, as is clear from FIG.
In order to eliminate the control deviation caused by the temporary change of the target rotation speed N _e ^T , the drive duty value (%) of the ISC valve is a feedforward control period in which the feedforward value α is followed by the drive duty value. Is the feedback value β and the stable control period is used. As a result, the rising period of the rotation speed of the engine 10 is shortened, and suitable control characteristics are obtained.

As described above, according to this embodiment, when the source pressure drop detecting means 100 detects a state in which the source pressure output from the hydraulic pump 56 drops, the source pressure raising means 102 causes the engine to rise. Since the rotational speed N _{e of} 10 is increased and the original pressure thereof is increased, the discharge capacity of the hydraulic pump 56 is likely to be insufficient due to the shift lever 96 being operated to the R range during forward traveling at a relatively low speed. even in a state, as shown in FIG. 6, the discharge capacity of the hydraulic pump 56 is raised the engine speed N _e by the original pressure increasing means 102 is increased, the reverse hydraulic friction engagement device The reverse control valve 70 is switched to the closed position before the engagement starts. Therefore, it is possible to reliably prevent the occurrence of a shock due to temporary engagement of the reverse hydraulic frictional engagement device due to the reduction of the original pressure.

Incidentally, in the conventional device which does not include the steps SH4 to SH6 as in the present embodiment, the shift lever 96 during forward traveling at a low vehicle speed of about 20 to 30 km / h in which the discharge capacity of the hydraulic pump 56 is low. Is operated from the forward travel (D, S, L) range to the R range, the reverse range pressure P _R is supplied to the clutch C2 through the 2-3 shift valve 68, and at the same time, the reverse control valve 70 is closed. Since the reverse range pressure P _R is supplied to the brake B3 through the reverse control valve 70 during the period until switching, a relatively large amount of hydraulic oil is consumed, and the discharge capacity of the hydraulic pump 56 is insufficient and the line pressure is reduced. P1 and the signal pressure P _IH generated therefrom decrease as shown by the alternate long and short dash line in FIG. In general, if the discharge capacity of the hydraulic pump 56 is sufficient, the throttle SS1 is provided, so for example, in the clutch C2 shown in FIG.
The signal pressure P _IH supplied to the chamber 74 of the reverse control valve 70 is spooled before reaching the minimum pressure P _PM required to move the 20 to the position shown by the broken line that causes the engagement between the friction plates 122. the valve member 71 is to reach the minimum pressure P _CM required to move to the closed position, but when the signal pressure P _{the IH} decreases as described above, the spool valve element 71 of the reverse control valve 70 a signal pressure P _{the IH} Since the operation of moving to the closed position is delayed by the action of, there is a disadvantage that a shock occurs due to the temporary establishment of the reverse gear.

Next, another embodiment of the present invention will be described. In the following description, the same parts as those in the above-described embodiment will be designated by the same reference numerals and the description thereof will be omitted.

The shift lever 96 shown in FIG. 8 is equipped with a switch 132 which is switched by a knob button 130 which is pressed when operating from the forward traveling range or N range to the R range or P range.
A signal S _NO indicating that the knob button 130 has been operated is output from 32. The electronic control unit 42 in the present embodiment operates according to the flowchart shown in FIG. 9 to temporarily increase the discharge capacity of the hydraulic pump 56 prior to the on-operation of the reverse travel preventing solenoid valve 54. In response to the operation, the increase in the rotation speed of the engine 10 is started.

In FIG. 9, in step SJ1, it is determined whether or not the shift lever 96 is operated to the N range. If the determination in step SJ1 is negative, it is determined in step SJ2 whether or not the shift lever 96 is operated to the R range, and this step SJ2 is performed.
If the determination is negative, the engine rotation increase control is stopped in step SJ3 because the vehicle is starting or traveling forward, and then the reverse control control routine of step SJ4 is executed to end this routine. . The reverse control control routine of step SJ4 is to turn on the reverse movement preventing solenoid valve 54 when the shift lever 96 is operated from the forward traveling range to the R range during forward traveling at a predetermined vehicle speed or higher,
For example, it is configured by steps excluding steps SH4 to SH6 in the flowchart of FIG.
If the vehicle is traveling backward, step S
Since the determination of J2 is affirmative, this routine is ended after the execution of step SJ4.

If the determination in step SJ1 is affirmative, it is determined in step SJ5 whether or not the knob button 130 has been pressed. If the determination in step SJ5 is positive, the vehicle speed V is previously set in step SJ6. It is determined whether or not it is larger than the determined determination reference value V ₀ , and if the determination in step SJ6 is affirmative, in the subsequent step SJ7 the N range holding time T _N
Is smaller than a predetermined determination reference value T ₀ , and if the determination in step SJ7 is affirmative, in the subsequent step SJ8, the engine rotation speed N _e is a predetermined determination reference value N _e0. Is lower than that. If any of the determinations in steps SJ5 to SJ8 is denied, step SJ9
In step SJ4, the step SJ4 is executed after the engine speed increase control is stopped.
If all the judgments in J8 are affirmed, step SJ
After the engine speed increase control is started in step 10, step SJ4 is executed.

Therefore, while the vehicle is stopped, the shift lever 9
In the state where 6 is operated to the N range, the determination at step SJ1 is affirmative, but the determination at step SJ5 or SJ6 is negative, so step SJ4 is executed through step SJ9. However, when the shift lever 96 is operated to the R range during forward traveling of the vehicle at a relatively low speed, the knob button 130 is pressed and passed through the N range. Therefore, the steps SJ1, SJ5, SJ6, Since the determinations of SJ7 and SJ8 are affirmative, the reverse control routine of step SJ4 is executed after the engine speed increasing control is started in step SJ10. This engine speed increase control is executed in the same manner as step SH6 of FIG. 5 described above. In this embodiment, the steps SJ1, SJ5,
SJ6, SJ7 and SJ8 are the source pressure drop detecting means 100.
The step SJ10 corresponds to the source pressure increasing means.

According to this embodiment, as in the above-described embodiments, the step SJ corresponding to the source pressure drop detecting means 100 is performed.
When the state in which the source pressure output from the hydraulic pump 56 decreases is detected by 1, SJ5, SJ6, SJ7, SJ8, step SJ1 corresponding to the source pressure increasing means 102.
Since the source pressure is increased rotational speed N _e of the engine 10 is being raised by 0, the discharge capacity of the hydraulic pump 56 is by shift lever 96 is operated to the R range during the relatively slow forward travel Even in a state where the shortage is likely to occur, the engine rotation speed N _e is increased and the discharge capacity of the hydraulic pump 56 is increased. Therefore, the reverse control valve is provided before the engagement of the reverse hydraulic friction engagement device is started. 70 is switched to the closed position, and the shock due to the temporary engagement of the reverse hydraulic frictional engagement device is reliably prevented.

Further, according to this embodiment, since the engine speed increasing control is started before shifting to the R range,
Compared with the embodiment shown in FIG. 5, there is an advantage that the response delay of the increase of the engine speed is reduced, and the shock can be surely prevented also in this respect.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other modes.

For example, step SH6 of the above-described embodiment.
Alternatively, the engine rotation speed increase control in step SJ10 is executed by switching the target rotation speed of the ISC control of the engine electronic control unit 110 to a value higher by a predetermined value. Instead, the opening θ of the throttle valve 87 is changed. _Even if a means for increasing the engine speed N _e by temporarily increasing _th by a predetermined value, temporarily increasing the fuel injection amount, or temporarily changing the ignition timing is adopted. Good.

In the engine speed increase control of the above-described embodiment, the electronic control unit 110 for engine temporarily increases the engine speed N _e according to the command from the electronic control unit 42. 42 is ISC
The valve, the throttle valve 87, or the fuel injection valve may be directly operated and controlled.

Further, in the above-mentioned embodiment, the decrease of the original pressure output from the hydraulic pump 56, that is, the line pressure P1 is detected by judging whether or not the condition for generating it is satisfied. The pressure sensor may be used to detect the actual decrease of the line pressure P1.

Further, the automatic transmission 14 of the above-mentioned embodiment is
3 sets of single pinion type planetary gear units 34, 36, 3
8 and a hydraulic friction engagement device C for engaging these elements
It was a mechanism that 4 forward gears and 1 reverse gear were established by 0, C1, C2, B0, B1, B2 and B3, but the configurations of these planetary gear units and hydraulic friction engagement devices were variously changed. It is also possible to use it as an auxiliary transmission such as a continuously variable transmission.

Further, the reverse movement preventing solenoid valve 5 of the above-mentioned embodiment.
4 can also be shared with the third solenoid valve 50 that executes the engagement control of the lockup clutch 32. That is, when the reverse range is executed and the vehicle speed is changed from the D range to the R range, the third solenoid valve 50 is turned on.
Even in this state, by applying the R range pressure so as to prevent the movement of the spool valve element of the lock-up relay valve (not shown), the reverse blocking can be achieved without engaging the lock-up clutch 32. Further, in normal D range traveling, the reverse control valve 70 is acted on by the D range pressure so as not to be in the reverse travel prevention state at the time of lockup. As a result, the reverse solenoid valve 54 and the third solenoid valve 50 can be shared by one solenoid valve.

The above description is merely an embodiment of the present invention, and the present invention can be variously modified without departing from the gist thereof.

[Brief description of drawings]

FIG. 1 is a diagram showing a vehicle power transmission device to which a hydraulic control device for an automatic transmission for a vehicle according to an embodiment of the present invention is applied.

2 is a diagram showing a relationship between a gear stage established in the automatic transmission of FIG. 1 and an operating state of a hydraulic friction engagement device.

FIG. 3 is a diagram illustrating a configuration of a main part of the hydraulic control circuit of FIG.

FIG. 4 is a functional block diagram illustrating an essential part of the operation of the electronic control device of FIG.

5 is a flowchart illustrating a control operation of the electronic control device of FIG.

FIG. 6 is a time chart illustrating the operation of the electronic control device of FIG.

FIG. 7 is a diagram illustrating an operating state of a piston in the clutch C2 in FIG.

FIG. 8 is a diagram illustrating a configuration of a shift lever according to another embodiment of the present invention.

9 is a flow chart for explaining the operation of the electronic control unit in the embodiment of FIG.

[Explanation of symbols]

10: Engine 14: Automatic transmission 56: Hydraulic pump 60: Manual valve (switching valve) 70: Reverse control valve 96: Shift lever 100: Source pressure drop detecting means 102: Source pressure increasing means Brake B2, Clutch C1: For forward movement Hydraulic friction engagement device Brake B3, clutch C2: reverse hydraulic engagement device

Claims (1)

[Claims] 1. An automatic transmission for a vehicle, wherein a forward gear stage or a reverse gear stage is established in accordance with the operation of a forward or reverse hydraulic frictional engagement device, the hydraulic frictional engagement being driven by rotation of an engine. A hydraulic pump that outputs an original pressure for operating the device and an R range pressure supplied to the reverse hydraulic friction engagement device based on the operation of the shift lever to the reverse range from the original pressure. A switching valve to be generated, an oil path between the reverse hydraulic frictional engagement device and the switching valve is opened to allow an establishment of a reverse gear stage, and the oil path is closed to establish a reverse gear stage. A reverse control valve having a valve positioned in a closed position that blocks the valve, and the valve is switched from the open position to the closed position by applying a signal pressure; The shift A hydraulic pressure control device comprising: a signal pressure generating unit that applies the signal pressure to the valve when the bar is operated to the R range, and an element that detects a state in which the original pressure falls below a predetermined value. And a source pressure increase means for increasing the source pressure by increasing the engine rotation speed when a state where the source pressure decreases is detected by the source pressure decrease detection means. A hydraulic control device for an automatic transmission for a vehicle, comprising: