JP3302780B2 - Control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission for appropriately controlling the operation timing of a friction element during a gear shift.

[0002]

2. Description of the Related Art Generally, automatic transmissions mounted on vehicles are
By combining a torque converter and a transmission gear mechanism and selectively operating a plurality of friction elements such as a clutch and a brake, the power transmission path of the transmission gear mechanism is switched to automatically shift, and 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 friction elements.

The above hydraulic control circuit is disclosed in, for example,
As shown in Japanese Patent No. 246652, a pressure regulator valve for adjusting line pressure, a manual valve for switching a range by manual operation, and a plurality of friction elements are selectively operated by switching an oil passage leading to each of the actuators. The vehicle includes a shift valve and a solenoid valve that receives a control signal corresponding to an operation state and drives each shift valve.

[0004] In such an automatic transmission, the operating state of each friction element may be set to be switched by supplying an operating oil pressure to at least two specific friction elements at a predetermined speed change. That is, the automatic transmission includes a 3-4 clutch engaged at the third speed and the fourth speed, and a 2-4 brake engaged at the second speed and the fourth speed. 3)
The hydraulic pressure for engagement is supplied to the four clutches, and the 3-4 clutch is switched from the disengaged state to the engaged state.
The shift is executed by supplying the release hydraulic pressure to the −4 brake and switching the 2-4 brake from the engaged state to the released state.

[0005]

As described above, at the time of a predetermined shift, at least two specific friction elements are supplied with hydraulic pressure to switch the operating state of each specific friction element. If the timing at which the gear changes and the timing at which the other friction element switches are not properly adjusted, a smooth shift cannot be performed. That is,
In the above example, if the release operation of the 2-4 brake is relatively too early relative to the engagement operation of the 3-4 clutch at the time of the 2-3 shift, the speed change mechanism is temporarily set in the neutral state and the engine speed is reduced. If the release operation of the 2-4 brake is too slow, a shift shock due to a drop in rotation occurs.

Therefore, at the time of the above-mentioned predetermined shift,
It is necessary to adjust the supply timing of the operating oil pressure to each of the friction elements in order to perform a smooth shift, but since the adjustment of the hydraulic pressure supply timing to each of the friction elements is merely performed individually, one of the friction elements is adjusted. The relationship between the switching timing of the second frictional element and the switching timing of the other frictional element is not always adjusted optimally, and the above-described rotation blow-up may occur.

In order to solve the above-mentioned problems, orifices are provided in oil passages leading to the actuators provided in the friction elements, and bypass passages are provided to bypass these orifices. A timing valve has been installed in Japanese Patent Application Laid-Open No. 2-76968. In such a configuration, the timing valve and its control means adjust the supply / discharge timing of the hydraulic pressure at the time of the predetermined shift, in conjunction with the action of the orifice provided in each oil passage.

However, in the control device having the above configuration, it is necessary to provide a control means for controlling the operation timing of the timing valve, and the structure is complicated, and the timing of switching the friction elements is easily shifted. There's a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the switching timing of the frictional elements is appropriately set to effectively suppress an increase in engine speed during shifting and the occurrence of a shifting shock. It is an object of the present invention to provide a control device for an automatic transmission that can perform the control.

[0010]

The invention according to claim 1 is
A control device for an automatic transmission, comprising: a friction element provided in a transmission gear mechanism for switching a power transmission path thereof; and a hydraulic control circuit for controlling a hydraulic pressure supplied to the friction element. A pressure regulating circuit for supplying a hydraulic pressure adjusted to a predetermined pressure to the friction element at an early stage of a shift, between a shift valve for discharging and a friction element, and supplying a line pressure to the friction element at a late stage of a shift. and the line pressure circuit, when the line pressure circuit and regulating pressure circuit selectively providing the selection switching means for communicating with the friction element together
To suppress the drain of the pressure regulation circuit at the later stage of shifting.
Means are provided .

According to a second aspect of the present invention, there are provided a plurality of friction elements provided in a transmission gear mechanism for switching a power transmission path thereof, and a hydraulic control circuit for controlling a hydraulic pressure supplied to these friction elements, A control device for an automatic transmission configured to supply an oil pressure to a plurality of friction elements at a predetermined speed and to switch an operation state of each friction element, comprising: a shift valve that supplies and discharges an oil pressure to each of the friction elements. A pressure adjusting circuit for supplying a hydraulic pressure adjusted to a predetermined pressure to a specific friction element at an early stage of a shift between the friction elements, and a line pressure for supplying a line pressure to the specific friction element at a late stage of a shift. A circuit and selection switching means for selectively communicating the line pressure circuit and the pressure regulating circuit with the friction element,
A second selection switching means for supplying hydraulic pressure to another friction element at a later stage of the shift, and a drain control line for supplying a hydraulic pressure for drain suppression to the pressure regulating circuit in accordance with the operation of the second selection switching means. It is characterized by having been provided.

[0012]

According to the first aspect of the present invention, the hydraulic pressure adjusted to a predetermined pressure by the pressure regulating circuit is supplied to the friction element in the initial stage of the gear shift, and the friction element is brought into a state immediately before the operation. When the line pressure is supplied from the line pressure circuit to the friction element at a later stage, the friction element shifts to the operating state.

At this time, a hydraulic pressure supply circuit for the friction element
Is changed from the pressure regulation circuit to the line pressure circuit
The drainage of the pressure regulation circuit
Ri, is wasted driving force of the hydraulic pump for supplying hydraulic pressure to each portion
Will be suppressed.

According to the second aspect of the present invention, when the second selection switching means is activated in the later stage of the shift, the pressure control circuit is operated in accordance with the hydraulic pressure supplied from the drain control line to the pressure control circuit. Will be suppressed.

[0015]

FIG. 1 schematically shows an example of the mechanical structure of an automatic transmission to which the present invention is applied. The automatic transmission 10 includes a torque converter 20, a multi-stage transmission gear mechanism 30 connected to an output side thereof, and a transmission gear mechanism 3.
A plurality of friction elements 41 to 46, such as clutches and brakes, for switching the power transmission path, and a one-way clutch 5.
1, 52.

The torque converter 20 includes a pump 22 fixed in a case 21 connected to the output shaft 1 of the engine, and a turbine disposed to face the pump 22 and driven via hydraulic oil. 23 and the pump 2
A stator 25 is provided between the turbine 2 and the turbine 23 and supported by the transmission case 11 via a one-way clutch 24 to increase the torque.

The rotational force of the turbine 23 is transmitted to the transmission gear mechanism 30 via a turbine shaft 27. Further, the torque converter 20 is provided with a lock-up clutch 26 that directly connects the input side and the output side. The engine output shaft 1 is connected to a pump shaft 12 penetrating through a turbine shaft 27, and the pump shaft 12 drives an oil pump 13 provided at the rear end of the automatic transmission. ing.

The speed change gear mechanism 30 is constituted by a Ravigneaux type planetary gear device provided on the turbine shaft 27. This planetary gear device includes a small-diameter sun gear 31 loosely fitted to a turbine shaft 27 and a turbine shaft 2 behind the small-diameter sun gear 31.
7; a plurality of short pinion gears 33 meshed with the small diameter sun gear 31;
The first half meshes with the short pinion gear 33 and the second half meshes with the large diameter sun gear 32, the long pinion gear 34, the carrier 35 rotatably supporting the short pinion gear 33 and the long pinion gear 34, and meshes with the long pinion gear 34. Ring gear 36. The output gear 14 is connected to the ring gear 36.

A forward clutch 41 and a first one-way clutch 51 are interposed between the turbine shaft 27 and the small-diameter sun gear 31, and a coast clutch 42 is interposed in parallel with the clutches 41 and 51. Have been. Further, the turbine shaft 27 and the carrier 3
A 3-4 clutch 43 is interposed between the clutch 5 and the clutch 5.
A reverse clutch 44 is interposed between the turbine shaft 27 and the large-diameter sun gear 32.

Between the large diameter sun gear 32 and the reverse clutch 44, a 2-4 brake 45 comprising a band brake for fixing the large diameter sun gear 32 is provided.
Further, between the carrier 35 and the transmission case 11, a second one-way clutch 52 for receiving the reaction force of the carrier 35 and a low-reverse brake 46 for fixing the carrier 35 are provided in parallel.

The transmission mechanism 30 is capable of moving forward 4 by itself.
The clutch 41-44 and the brakes 45, 46 are appropriately operated based on a select operation for selecting a range and a control according to an operating state, so that a gear in the D range is provided. 1st to 4th, 1 in 2 ranges
The third speed, the first and second speeds in one range, and the reverse speed in the R range are obtained.

Here, the relationship between the operating state of each of the clutches 41 to 44, the brakes 45 and 46, and the one-way clutches 51 and 52 and the shift speed will be described. First, in first gear, while the forward clutch 41 is engaged,
The first and second one-way clutches 51 and 52 are locked, and the output rotation of the torque converter 20 is transmitted from the turbine shaft 27 to the forward clutch 41 and the first
Via the one-way clutch 51, the small-diameter sun gear 31
Is input to

The rotation is transmitted from the small diameter sun gear 31 to the ring gear 36 via the short pinion gear 33 and the long pinion gear 34 in a state where the carrier 35 is fixed by the action of the second one-way clutch 52. As a result, the small-diameter sun gear 31 and the ring gear 36
The first speed state with a large reduction ratio corresponding to the ratio of the diameter to the first speed is obtained.

Next, in the second speed, in addition to the state of the first speed, the 2-4 brake 45 is engaged, the large-diameter sun gear 32 is fixed, and the second one-way clutch 52 is idle. Therefore, the rotation transmitted from the turbine shaft 27 to the small-diameter sun gear 31 is transmitted to the long pinion gear 34 via the short pinion gear 33, and the long pinion gear 34 revolves on the large-diameter sun gear 32, so that the carrier 35 Rotates. As a result, the rotation of the ring gear 36 is increased by the rotation of the carrier 35 compared to the first speed state, and a second speed state with a smaller reduction ratio than in the first speed state is obtained.

In the third speed, the state of the second speed is changed to the second speed.
At the same time that the -4 brake 45 is released, the 3-4 clutch 43 is engaged. Therefore, the turbine shaft 27
Is input to the small-diameter sun gear 31 via the forward clutch 41 and the first one-way clutch 51, and at the same time, the carrier 35 is transmitted via the 3-4 clutch 43.
Will also be entered. As a result, the transmission gear mechanism 3
0 rotates integrally and the ring gear 36 rotates at the same speed as the turbine shaft 27 to obtain a third speed state.

At the 4th speed, the 2-4 brake 45 once released at the 3rd speed is engaged again.
Therefore, the rotation of the turbine shaft 27 is input from the 3-4 clutch 43 to the carrier 35, and the long pinion gear 34 revolves. The large-diameter sun gear 32 meshed with the long pinion gear 34
Since the pinion gear 34 is fixed by the brake 45, the long pinion gear 34 rotates while revolving with the carrier 35. As a result, the ring gear 36 meshing with the long pinion gear 34 is rotated by the rotation of the carrier 35 by an amount corresponding to the rotation of the long pinion gear 34, whereby the fourth speed in the overdrive state is obtained.

Further, in the reverse speed, the reverse clutch 44 and the low reverse brake 46 are engaged.
The rotation of the turbine shaft 27 is input to the large-diameter sun gear 32, and the carrier 35 is
Fixed to 1. For this reason, rotation is transmitted via a fixed gear train from the large-diameter sun gear 32 to the ring gear 36 via the long pinion gear 34, and the reduction ratio corresponding to the diameter ratio between the large-diameter sun gear 32 and the ring gear 36 is reduced. And the ring gear 36 is
Rotate in the opposite direction to 7.

The first one-way clutch 51 for transmitting the rotation at the first to third speeds and the second one-way clutch 52 for receiving the reaction force at the first speed run idle during coasting, so that the engine brake operates at these speeds. It will not be done, but D range 3 speed, 2 range 2, 3
In the first and second speeds of the first speed and the first range, the coast clutch 42 in parallel with the first one-way clutch 51 is engaged.
At the first speed in the range, the low / reverse brake 46 in parallel with the second one-way clutch 52 is engaged, so that engine braking is obtained at these shift speeds.

Table 1 below summarizes the relationship between the operation of each of the friction elements 41 to 46 and the one-way clutches 51 and 52 and the shift speed.

[0030]

[Table 1]

The essential part of the hydraulic control circuit 60 for supplying and discharging the hydraulic pressure to the actuators of the friction elements 41 to 46 will be described with reference to FIG. Here, among the above actuators, the hydraulic actuator of the 2-4 brake 45 includes a servo piston having a servo release chamber 61 and a servo apply chamber (not shown), and hydraulic pressure is supplied only to the servo apply chamber. In this case, the 2-4 brake 45 is engaged, otherwise, the 2-4 brake 45 is engaged.
Is configured to be released. Further, the actuators of the other friction elements 41 to 44 and 46 are composed of ordinary hydraulic pistons, and are adapted to fasten the friction elements when hydraulic pressure is supplied.

The hydraulic control circuit 60 includes, as main components, a pressure regulator valve 63 for adjusting the pressure of the hydraulic oil discharged from the oil pump 13 to the main line 62 to a predetermined line pressure (PL pressure), and a manual valve. Manual valve 64 for selecting a range by operation
And a 1-2 shift valve (not shown) which operates in accordance with the shift speed to supply / discharge hydraulic pressure to / from each of the friction elements 41 to 46, and each shift of a 2-3 shift valve 65 and a 3-4 shift valve 66. And a valve.

The manual valve 64 has an input port e through which line pressure is introduced from the main line 62 and a first port e.
To the fourth output ports a to d, and the input port e corresponds to the first and second output ports a and b in the D range and the second range according to the movement of the spool 62a. The three output ports a and c are connected to the fourth output port d in the R range. First to fourth output lines are connected to the output ports a to d, respectively.

The 2-3, 3-4 shift valve 6
The spools 65a, 66a of the spools 5a, 66a are urged to the right in the figure by springs (not shown), and pilot ports 65b, 66b are provided on the right side of the spools 65a, 66a. The pilot ports 65b and 66b of the 2-3 shift valve and 3-4 shift valves 65 and 66 are connected to the second and third pilot lines 67 and 68, respectively, branched from the first output line. In addition, the pilot line 6
7 and 68 have second and third solenoid valves 6 respectively.
9, 70 are provided.

The second and third solenoid valves 69, 7
0 indicates pilot lines 67 and 6 when each is ON.
8 to drain the pilot pressure in the pilot ports 65b and 66b, so that the spool 65
a, 66a are located on the right side of the figure, and when the switch is off, the pilot port 65
The spools 65a and 66a are positioned on the left side in the drawing by introducing pilot pressure to the spools b and 66b.

The second and third solenoid valves 69, 7
The first solenoid valve provided on the pilot line of the 0-shift valve and the 1-2 shift valve (not shown) controls the control output from the control circuit based on a map set in advance corresponding to the vehicle speed and the throttle opening of the engine. O according to the signal
N, OFF control is performed, and by operating each shift valve in accordance with the N / OFF control, engagement and release of the friction elements 41 to 46 are performed so as to obtain a shift speed corresponding to an operation state. ON, O of the first to third solenoid valves
The relationship between the FF and the combination pattern is set as shown in Table 2 below.

[0037]

[Table 2]

Of the first to fourth output lines connected to the output ports a to d of the manual valve 62, the second output line 72 communicating with the main line 62 in the D and 2 ranges is a 2-3 shift line. The second solenoid valve 69 is turned off (spool 65
a is the left position), the second output line 7
2 communicates with the 3-4 clutch line 73. This 3-4
The clutch line 73 reaches the 3-4 clutch 43 via the one-way orifice 74. Accordingly, the hydraulic pressure is supplied to the 3-4 clutch 43 at the 3rd speed of the D range and the 3rd speed of the 2 range where the second solenoid valve 69 is turned off.

In addition, at the time of 3-2 downshift, 4-2 downshift, 3-1 downshift or 4-1 downshift, the second solenoid valve 69 is turned on.
As a result, the spool 65a of the 2-3 shift valve 65 is located on the left side, so that the hydraulic pressure in the 3-4 clutch line 73 is drained. An accumulator 75 acts as a shock absorber when the 3-4 clutch operates.

The second solenoid valve 69 branches off from the 3-4 clutch line 73 and turns off (spool 64a
Is turned to the left position), the branch line 73a communicating with the second output line 72 is guided to the 3-4 shift valve 66, and the third solenoid valve 70 is turned off (spool 6).
When 6a is at the left position), it communicates with the servo release line 77 via the first line 76 and a selection switching means including a 2-3 timing valve 78 described later.
This servo release line 77 has a 2-4 brake 45
Is connected to the release port 45b.

The 3-4 shift valve 66, 2
-3 timing valve 78, pressure regulating valve 80
A second line 79 provided in parallel with the first line 76 is provided. The hydraulic pressure adjusted to a predetermined pressure by the pressure regulating valve 80 in an initial stage at the time of 2-3 shifting, which will be described later, is applied to the servo release line 77. Through the release port 45b. That is,
The pressure regulating valve 80 performs the pressure regulating function by adjusting the opening ratio of the drain port in accordance with the throttle modulator pressure (PM pressure) supplied from a throttle modulator valve 88 described later. It is configured to:

A branch line 81 branched from the servo release line 77 is provided downstream of the 2-3 timing valve 78. The branch line 81 communicates with a coast clutch line 86 via a second selection switching means including a coast timing valve 83, a one-way orifice 84 and a ball valve 85, and reaches the coast clutch 42. On the other hand, the branch line 81 branches from the downstream side of the coast timing valve 83 and is connected to one end 80 b of a spool 80 a of the pressure regulating valve 80.
Is provided with a drain control line 87 communicating with.

The hydraulic control circuit 60 is provided with a throttle modulator valve 88 for controlling the pressure regulator valve 63 by applying a throttle modulator pressure (PM pressure) to the pressure increasing port of the pressure regulator valve 63. Is provided. The throttle modulator valve 88 is configured to generate a throttle modulator pressure corresponding to a duty ratio of a duty solenoid valve. The duty ratio is set according to the throttle opening of the engine,
A throttle modulator pressure corresponding to the throttle opening is applied to the pressure regulator valve 63.

In addition to the above configuration, the hydraulic control circuit 60 includes a release port 45b for the 3-4 clutch 43 and the 2-4 brake 45 at the time of 2-3 upshift.
When the engagement of the 3-4 clutch 43 and the release of the 2-4 brake 45 are performed by supplying the hydraulic pressure to the 3-4 clutch 43, the bypass valve 89 for adjusting the operation timing of the 3-4 clutch 43 is provided.
Is provided. This bypass valve 89 is 3-4
The one-way orifice 74 provided in the clutch line 73 is provided in a bypass line 90 which bypasses the one-way orifice 74. The hydraulic pressure downstream of the one-way orifice 73 is introduced into one end of the spool 89a, and the other end of the spool 89a is supplied to the other end of the spool 89a. , Throttle modulator valve 8
Eight throttle modulator pressures (PM pressures) are introduced.

When the hydraulic pressure of the 3-4 clutch line 73 rises above a predetermined value and the spool 89a of the bypass valve 89 moves to the left, the bypass line 90 is cut off. Therefore, 3-
In the case where the four clutch 43 is switched from the disengaged state to the engaged state, when the supply of the hydraulic pressure to the 3-4 clutch 43 is started, the hydraulic pressure is promptly supplied by the bypass line 90. The supply of hydraulic pressure is moderated by the orifice 74, and thus the engagement timing of the 3-4 clutch 43 during the 2-3 shift-up shift is adjusted.

The spool 78a of the 2-3 timing valve 78 provided on the servo release line 77
Is connected to a line 91 communicating with the 3-4 clutch line 73, and a throttle modulator pressure (PM pressure) is introduced to the other end 78c.
One of the first line 76 and the second line 79 is moved to the servo release line 77 by the control hydraulic pressure including the hydraulic pressure in the 3-4 clutch line 73 introduced through the line 91 and the action of the throttle modulator pressure. And the servo release pressure is regulated.

That is, the above-mentioned 3-4 clutch line 73
In the initial stage at the time of the 2-3 shift in which the oil pressure in the inside is low, the spool 78a of the 2-3 timing valve 78 moves the one end portion 78b side (left side) according to the throttle modulator pressure.
And the second line 79 is the servo release line 77
The hydraulic pressure adjusted to a predetermined pressure by the pressure regulating valve 80 is supplied to the servo release chamber 45a via the second line 79.

When the oil pressure in the 3-4 clutch line 73 increases in the latter stage of the 2-3 shift, the spool 7 of the 2-3 timing valve 78 is operated in accordance with the oil pressure.
8a is displaced to the other end 78c side (right side), and the first line 7
6 communicates with the servo release line 77,
The high line pressure in the second output line 72 is supplied to the servo release chamber 45a via the first line 76.

When the line pressure is supplied into the servo release chamber 45a and the 2-4 brake 45 is released, the hydraulic pressure in the servo release line 77 is applied to the coast clutch line 86 via the branch line 81. The coast clutch 42 is supplied to the engaged state. Then, the hydraulic pressure in the branch line 81 is changed to the drain control line 8
7, one end 8 of the spool 80a of the pressure regulating valve 80
By supplying the pressure to 0b, the operation of the pressure regulating valve 80 is prohibited and the drain of the hydraulic pressure is stopped.

As described above, the 3-4 shift valve 66 for controlling the supply and discharge of the hydraulic pressure to and from the servo release line 77 at the time of the 2-3 shift, and the 2-3 timing valve for controlling the supply timing of the hydraulic pressure to the servo release line 77. 78 and a first line 76 for supplying line pressure.
And a pressure regulating circuit comprising a second line 79 provided with a pressure regulating valve 80 are provided in parallel, and the pressure is adjusted to a predetermined pressure by the pressure regulating circuit 79 having the pressure regulating valve 80 at the initial stage of the 2-3 shift. After the supplied hydraulic pressure is supplied to the servo release line 77, the line pressure is supplied from the line pressure circuit 76 to the servo release circuit 77 from the line pressure circuit 76 by a selection switching means including a 2-3 timing valve at a later stage of the shift. With this configuration, it is possible to perform a smooth shift without causing a shift shock.

That is, as shown in FIG. 3, at a time point T2 when a predetermined time has elapsed from the shift start time point T1, the servo release pressure is increased from 0 to the release pressure at a stretch. -4 brake 45
Cannot be immediately moved to the released state,
As a result, it has not been possible to prevent the occurrence of a retraction shock in which the drop in the acceleration (G waveform) of the vehicle temporarily increases.

On the other hand, as shown in FIG. 4, the hydraulic pressure adjusted to the set pressure immediately before the release of the 2-4 brake 45 by the pressure regulating valve 80 of the pressure regulating circuit at the shift start time T1 is used as the servo release pressure. After acting, the above 3-4
Engagement time T3 of 3-4 clutch 43 at which predetermined hydraulic pressure is supplied from clutch line 73 to 3-4 clutch 43
According to the present invention, in which the line pressure circuit including the first line 76 is connected to the servo release line 77 to supply the line pressure to the servo release chamber 45b, the servo release pressure is quickly released to the release pressure. As a result, the occurrence of the retraction shock can be prevented.

Further, in the above embodiment, 2-3 times of the D range
In the hydraulic control circuit 60 including the coast clutch 42 that operates together with the 2-4 brake 45 at the time of shifting,
As shown in FIG. 2, a drain control unit for a pressure regulating valve 80 including a drain control line 87 communicating with one end 80 a of the pressure regulating valve 80 is provided in a branch line 81 that supplies hydraulic pressure to the coast clutch 42. In the latter stage of the 2-3 shift, the pressure regulating valve 80 is operated in response to the hydraulic pressure supplied from the drain control means when the second selection switching means including the coast timing valve 83 is operated.
Is fixed to the drain prohibited state.

According to the above configuration, it is possible to reliably prevent the drainage of the pressure regulating valve 80 from being continued when unnecessary, without providing a solenoid valve or the like, and to waste the driving force of the oil pump 13 with a simple configuration. Can be effectively suppressed.

The drain control line 87 is replaced with a spool 80 of the pressure regulating valve 80 as shown in FIG.
A drain control line 93 having a fifth solenoid valve 92 is provided at one end 80b of the pressure control valve 80a by turning off the fifth solenoid valve 92 at a later stage of the 2-3 shift. May be fixed to the drain prohibited state.

In the example shown in FIG. 5, a third line 94 is provided for connecting the second line 79 located downstream of the pressure regulating valve 80 and the coast timing valve 83. Then, while shifting the 2-4 brake 45 from the engaged state to the released state, the coast clutch 42
At the time of the 4-3 shift in which the state is shifted from the release state to the engagement state,
The hydraulic pressure in the second line 79 is supplied to the coast timing valve 83 via the third line 94, and the operation state of the pressure regulating valve 80 provided in the second line 79 is controlled by the fifth solenoid 92. With this configuration, it is possible to effectively prevent the occurrence of coasting downshoot when the coast clutch 42 is engaged.

That is, in the conventional example shown in FIG. 6, a predetermined time has elapsed from the shift start time Ta, and the operating time T of the coast clutch 42 when the servo release pressure has risen to the set pressure.
b, the supply of the line pressure to the coast clutch 42 is started so that the coast clutch 42 is shifted to the engaged state at a stretch. Therefore, it is possible to avoid occurrence of a coasting downshoot when the coast clutch 42 is engaged. You can do things you couldn't do.

On the other hand, in the above embodiment, as shown in FIG.
Hydraulic pressure solution is supplied to the servo release chamber 45b via the
Rose to pressure relief, 2-4 operation time Tb of coast clutch 42 the brake is shifted to the released state, the hydraulic pressure third line 94 in the second line 79 is adjusted to a predetermined pressure by the pressure regulating valve 80 Coast clutch line 8 through
After the coast pressure is increased to the predetermined pressure, the line pressure introduced into the second line 79 is reduced to the coast clutch at the shift end time Tc when the fifth solenoid 92 is turned off. The coast clutch 42 is supplied to the line 86 and shifts to the engaged state.

Further, in the control hydraulic circuit 60 including the fifth solenoid 92 for controlling the operation state of the pressure regulating valve 80, as shown in FIG. -4 control valve 95
And the 3-4 control valve 95
And a connection line consisting of a fourth line 96 connecting the drain control line 93 having the fifth solenoid 92 to the drain control line 93.

In this case, as shown in Table 3 below,
At the time of the 4-1 shift, the 3-1 shift, or the 2-1 shift, an intermediate shift region is provided in which the fifth solenoid 92 is temporarily turned ON, and the 3-4 clutch 43 is connected via the 3-4 control valve 95. In this configuration, the shift responsiveness during the downshift is improved, and the occurrence of a shift shock can be effectively prevented.

[0061]

[Table 3]

[0062]

As described above, according to the present invention, the shift valve for controlling the supply and discharge of the hydraulic pressure to and from the friction element at the time of gear shifting and the hydraulic pressure adjusted to a predetermined pressure at the initial stage of the gear shift are provided between the friction element and the shift element. And a line pressure circuit for supplying a line pressure to the friction element at a later stage of the gear shift, and both circuits are selectively connected to the friction element by selection switching means. With this configuration, at the time of shifting start, the line pressure is applied to the friction element via the line pressure circuit at a predetermined time while the oil pressure adjusted to the set pressure immediately before the operation by the pressure adjustment circuit is applied to the friction element. By supplying, the friction element can be activated early. Therefore, it is possible to effectively prevent the occurrence of a retraction shock in which the acceleration of the vehicle body suddenly decreases during the shift, and to perform a smooth shift without causing a shift shock .

At this time, the pressure adjustment is performed at a later stage of the shift.
Drain suppression means for suppressing the drain of the circuit is provided.
Therefore, the line that communicates with the friction element
When the pressure regulator circuit is switched to the line pressure circuit,
Due to the continued operation and drainage
To effectively reduce waste of driving power of the oil pump
It has the effect that can be done.

In particular, in a control device for an automatic transmission configured to supply hydraulic pressure to a plurality of friction elements during a predetermined shift, a predetermined hydraulic pressure is supplied to a specific friction element such as a 2-4 brake or the like. An operation of a second selection switching means including a pressure regulating circuit and a drain control line for suppressing drainage of the pressure regulating circuit, and including a coast timing valve for controlling supply of hydraulic pressure to another friction element such as a coast clutch. Therefore, if the oil pressure for drain suppression is supplied to the pressure regulating circuit via the drain control line at the later stage of the gear shift, the oil pump can be simply configured without providing a solenoid valve or the like. It is possible to prevent the driving force from being consumed.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing the entire structure of an automatic transmission to which a control device according to the present invention is applied.

FIG. 2 is a circuit configuration diagram showing a main part of the control device.

FIG. 3 is a time chart showing a control state of hydraulic pressure at the time of 2-3 shift in a conventional example.

FIG. 4 is a time chart illustrating a control state of hydraulic pressure during a 2-3 shift according to the embodiment of the present invention.

FIG. 5 is a circuit diagram showing another embodiment of the control device.

FIG. 6 is a time chart showing a control state of hydraulic pressure at the time of 4-3 shift in a conventional example.

FIG. 7 is a time chart showing a control state of the hydraulic pressure at the time of the 4-3 shift in the embodiment shown in FIG. 5;

FIG. 8 is a circuit configuration diagram showing still another embodiment of the control device.

[Explanation of symbols]

Reference Signs List 10 automatic transmission 30 transmission gear mechanism 42 coast clutch (friction element) 43 3-4 clutch (friction element) 45 2-4 brake (friction element) 60 hydraulic control circuit 65 2-3 shift valve 66 3-4 shift valve 78 2-3 Timing valve (selection switching means) 76 First line (line pressure circuit) 79 Second line ( pressure regulation circuit) 80 Pressure regulation valve 83 Coast timing valve (second selection switching means) 87, 93 Drain control line ( Drain control means) 96 4th line (connection line)

Claims (2)

(57) [Claims] 1. A control device for an automatic transmission, comprising: a friction element provided in a transmission gear mechanism for switching a power transmission path thereof; and a hydraulic control circuit for controlling a hydraulic pressure supplied to the friction element. A shift valve for supplying / discharging hydraulic pressure to / from the element, a pressure regulating circuit for supplying a hydraulic pressure adjusted to a predetermined pressure to the friction element in an initial stage of shifting, and a line pressure in a late stage of shifting between the friction element. A line pressure circuit for supplying the friction element; and a selection switching means for selectively communicating the line pressure circuit and the pressure adjustment circuit with the friction element, and suppressing drainage of the pressure adjustment circuit at a later stage of the shift.
A control device for an automatic transmission, characterized in that a control means is provided . A plurality of friction elements provided in the transmission gear mechanism for switching a power transmission path thereof, and a hydraulic control circuit for controlling a hydraulic pressure supplied to the friction elements, wherein a plurality of friction elements are provided during a predetermined gear shift. A control device for an automatic transmission configured to switch the operation state of each friction element by supplying hydraulic pressure to the element, comprising: a shift valve that supplies and discharges a hydraulic pressure to each of the friction elements; In the meantime, a pressure regulating circuit for supplying a hydraulic pressure adjusted to a predetermined pressure to a specific friction element at an early stage of a shift, a line pressure circuit for supplying a line pressure to the specific friction element at a late stage of a shift, Selection switching means for selectively communicating the circuit and the pressure regulating circuit with the friction element, and second selection switching means for supplying hydraulic pressure to other friction elements at a later stage of the shift; and second selection switching means. For operation And a drain control line for supplying a hydraulic pressure for drain suppression to the pressure regulating circuit in response to the control signal.