JP2878476B2 - Transmission 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 shift control device for an automatic transmission.

[0002]

2. Description of the Related Art In an automatic transmission mounted on a vehicle, generally, the speed is changed by changing the operation mode of a plurality of frictional engagement elements which are both operated by hydraulic pressure. I have. That is, the operation mode of the plurality of frictional fastening elements is changed to change the usage mode of the gears interposed in the power transmission path. Therefore, when there is a "shift" in the timing of the operation change between these frictional engagement elements, there arises a problem such as a shift shock or engine idling.

To cope with such a problem, Japanese Patent Laid-Open No.
As disclosed in JP-A-45157, a timing valve is provided in a hydraulic circuit of an automatic transmission, and the operating pressure of one frictional engagement element is taken into this timing valve as a pilot pressure so that the other frictional engagement element can be used. The timing of the supply of the hydraulic pressure is adjusted.

In the above publication, as another friction engagement element, a 2-4 brake, that is, a piston that separates an engagement side oil chamber and a release side oil chamber is provided, and the piston receives the hydraulic pressure in each of these oil chambers. A friction fastening element that performs a fastening operation or a releasing operation based on a force difference is disclosed. That is, the 2-4 brake performs the releasing operation by discharging the hydraulic pressure of the engagement side oil chamber,
Alternatively, the release operation is performed by supplying hydraulic pressure to the release-side oil chamber.

[0005]

However, supplying hydraulic pressure to another frictional engagement element while supplying hydraulic pressure to one frictional engagement element means that the operating pressure of the one frictional engagement element is increased. Is likely to temporarily decrease. In particular, this problem occurs when the oil temperature is low, that is, when the viscosity of the hydraulic oil is high. That is, when it becomes difficult to quickly compensate the supply of the hydraulic pressure to the other frictional engagement elements due to the influence of the pipeline resistance in the hydraulic circuit, the operating pressure of one frictional engagement element is temporarily reduced. The problem of lowering is likely to occur.

Of course, the operating pressure of one frictional fastening element is
Even if it temporarily decreases, a shift occurs in the timing of the operation change between the friction engagement element and the other friction engagement element, and a phenomenon such as shift shock or idling of the engine speed occurs. Will happen.

Therefore, an object of the present invention is to prevent a "shift" from occurring in the timing of the operation change between the one friction fastening element and the other friction fastening element even when the oil temperature is low. To provide a shift control device for an automatic transmission.

[0008]

According to the present invention, there is provided a control unit for achieving the above object.
A plurality of frictional fastening elements 201 based on the command signal from 0,
A first valve that opens and closes a hydraulic supply path that supplies hydraulic pressure to the frictional engagement element in a hydraulic circuit of the automatic transmission that is configured to obtain a desired shift speed by changing the combination of engagement and release of 202 203, a second valve 204 for opening and closing a drain pressure path for discharging the oil pressure in the friction element
And the first and second valves 203, 2
04 is based on a shift control device of an automatic transmission that is opened and closed based on a shift command signal from the control unit 200.

The plurality of friction fastening elements 201, 202
, A frictional engagement element 201 that performs an engagement operation when hydraulic pressure is supplied, an engagement side oil chamber 202a and a release side oil chamber 2
02b is separated from the oil chamber 20 by the piston 205.
2a and other frictional fastening elements 202 that perform a fastening operation or a releasing operation based on the difference in force received from the hydraulic pressure.
And a timing valve 206 for controlling a hydraulic pressure supply timing for supplying a hydraulic pressure to the release-side oil chamber 202b of the other frictional coupling element 202 in response to the operating pressure of the one frictional coupling element 201. An oil temperature detecting means 207 for detecting an oil temperature in the hydraulic circuit, and an engagement start detecting means 20 for detecting an engagement start of the one frictional engagement element 201.
8 and that the gearshift command generated by the control unit 200 is a gearshift command to a gear that involves the engagement of the one frictional engagement element 201 and the release of the other frictional engagement element 202. Upon receiving signals from the shift command discriminating means, the shift command discriminating means and the oil temperature detecting means 207, a shift command generated by the control unit 200 is used to change the engagement of the one frictional engagement element 201 and the other. When a shift command to a shift speed accompanied by release of the friction engagement element 202 is made, according to the level of the oil temperature in the hydraulic circuit,
A shift control mode switching unit that sets a first shift control mode when the oil temperature is high, and sets a second shift control mode when the oil temperature is low, wherein the first shift control mode includes:
The timing valve 206 controls the hydraulic pressure supply timing of the other frictional engagement element 202 to the release-side oil chamber 202b, and the second shift control mode receives a signal from the engagement start detection means 208. Then, when the one frictional fastening element 201 starts its fastening, the second valve 204 provided in the exhaust pressure path connected to the fastening side oil chamber 202a of the other frictional fastening element 202 is opened. It has such a configuration.

That is, in the present invention, when the hot water temperature is low, the control for supplying the hydraulic pressure to the release-side oil chamber 202b of the other frictional engagement element 202 is stopped, and the hydraulic pressure of the engagement-side oil chamber 202a is drained. The other frictional fastening elements 202 are released.

[0011]

Therefore, at a low oil temperature where the resistance of the pipeline cannot be neglected, oil pressure is not supplied to one frictional engagement element 202 during supply of oil pressure to one frictional engagement element 201. Therefore, it is possible to reliably prevent a temporary decrease in the operating pressure of one frictional fastening element 201.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 2 shows an outline of the automatic transmission 10. This automatic transmission 10 includes a torque converter 20, a transmission gear mechanism 30 driven by an output of the torque converter 20, and a main gear 30 as main components. A plurality of friction fastening elements 41 to 46 such as clutches or brakes for changing the usage of gears interposed in the power transmission path of the mechanism 30
And one-way clutches 51 and 52, so that, for example, in each range position of D, 2, and 1 as the travel range, for example, in the D range, each of the first to fourth speeds can be obtained.

The torque converter 20 includes a pump 22 fixed to a pump case 21 connected to the engine output shaft 1 and a pump 22 disposed opposite to the pump 22 via hydraulic oil by the pump 22. A driven turbine 23;
A stator 25 interposed between the pump 22 and the turbine 23 and supported by the transmission case 11 via a one-way clutch 24 to increase the torque; The engine output shaft 1 and the turbine 23 are provided between the turbine 23 and the pump case 21.
And a lock-up clutch 26 that is directly connected to the transmission mechanism 30. The rotation of the turbine 23 is output to the transmission mechanism 30 via a turbine shaft 27.

Here, the engine output shaft 1 has a
Pump shaft 1 extending through bin shaft 27
2 is connected to the front end of the transmission 10 by the shaft 12.
The drive of the oil pump 13 provided at the rear end portion is performed.

The speed change gear mechanism 30 is constituted by a Ravignon type planetary gear device,
7, a small-sized small sun gear 31 loosely fitted on the shaft 7, a large-diameter large sun gear 32 loosely fitted on the turbine shaft 27 at the rear of the sun gear 31, and a front half of the small sun gear 31. A long pinion gear 34 meshed with a top pinion 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 33; and a front half of the long pinion gear 34 And a ring gear 36 meshed with.

A forward clutch 41 is provided between the turbine shaft 27 and the small sun gear 31.
And a first one-way clutch 51 are interposed in series,
A cost clutch 42 is provided in parallel with the clutches 41 and 51. A 3-4 clutch 43 is interposed between the turbine shaft 27 and the carrier 35. Further, a reverse scratch 44 is interposed between the turbine shaft 27 and the large sun gear 32.

Further, between the large sun gear 32 and the reverse scratch 44, a 2-4 brake 45 composed of a band brake for fixing the large 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 roller brake 46 for fixing the carrier 35 are arranged in parallel. It is provided in. The ring gear 36 is connected to the output gear 14, and the rotational force is transmitted from the output gear 14 to left and right wheels (not shown) via a differential device.

Next, the relationship between the operating states of the frictional engagement elements 41 to 46 and the one-way clutches 51 and 52 and the gears will be described.

The first speed forward clutch 41 is engaged, and the first and second one-way clutches 51 and 52 are locked. For this reason, the output rotation of the torque converter 20 is controlled by the small sun gear 3 from the turbine shaft 27 via the forward clutch 41 and the first one-way clutch 51.
1 is input. In this case, the second one-way clutch 5
2, the carrier 35 is fixed by the action of 2, so that the planetary gear device 30
The rotation is transmitted to the ring gear 36 via the top pinion gear 33 and the long pinion gear 34. In other words, since it operates as a fixed gear train that does not perform the operation, a first speed state with a large reduction ratio corresponding to the ratio between the small sun gear 31 and the ring gear 36 is obtained.

Second speed In addition to the first speed state, a 2-4 brake 45 operates,
The large sun gear 32 in the planetary gear device 30 is fixed, and the second one-way clutch 52 is idle. Therefore, the rotation transmitted from the turbine shaft 27 to the small sun gear 31 is transmitted to the long pinion gear 34 via the short pinion gear 33. Here, the long pinion gear 34 revolves on the large sun gear 32 because the large sun gear 32 meshing with the long pinion gear 34 is fixed, and the carrier 35 rotates accordingly. Accordingly, the rotation of the ring gear 36 is increased by the rotation of the carrier 35 (the revolution of the long pinion gear 34) compared to the first speed state, and a second speed state having a smaller reduction ratio than in the first speed state is obtained.

In the third speed and the third speed, the 2-4 brake 4
5 is released, and the 3-4 clutch 43 is engaged. Therefore, the rotation of the turbine shaft 27 is controlled by the forward clutch 41 and the first one-way clutch 51.
Is input to the small sun gear 31 via
The signal is also input to the carrier 35 via the 3-4 clutch 43. Therefore, the entire planetary gear device 30 rotates integrally, and the ring gear 36 is rotated by the turbine shaft 27.
A third speed state in which the motor rotates at the same speed as that of the second speed is obtained.

In the fourth speed and the fourth speed, the two-speed gear is once released in the third speed.
The four brakes 45 are fastened again. Therefore, the rotation of the turbine shaft 27 is input to the carrier 35 of the planetary gear device 30 from the 3-4 clutch 43, and the long pinion gear 34 revolves. At this time, the large sun gear 32 meshed with the long pinion gear 34
Is fixed by the 2-4 brake 45, the long pinion gear 34 rotates while revolving with the carrier 35.

Accordingly, the ring gear 36 meshing with the long pinion gear 34 is rotated by the rotation of the carrier 35 (rotation of the turbine shaft 27) at an increased speed by the rotation of the long pinion gear 34. Fourth speed in the ball drive state is obtained. In this case, although the forward clutch 41 is in the engaged state, the rotation of the turbine shaft 27 is not input to the small sun gear 31 because the first one-way clutch 51 in series with the forward clutch 41 idles. Absent.

When the reversing reverse scratch 44 and the low reversing brake 46 are fastened, the rotation of the turbine shaft 27 is controlled by the above-mentioned rotation.
The rotation is transmitted to the diver gear 32 and transmitted through a fixed gear train extending from the radi gear 32 to the long pinion gear 34 and the ring gear 36.

As described above, the engagement or release of each of the friction engagement elements 41 to 46 is controlled by a hydraulic circuit (a part of which is shown in FIG. 1). Where 2
The high gear is obtained by disengaging the 3-4 clutch 43 and engaging the 2-4 brake 45. On the other hand, the third gear is the above-mentioned 3-
This is obtained by setting the four clutch 43 to the engaged state and setting the 2-4 brake 45 to the released state. Accordingly, in shifting from the second speed to the third speed, the operating state of the 3-4 clutch 43 is changed from the disengaged state to the engaged state, and the 2-4 brake 45 is engaged. Is changed to the released state.

FIGS. 1 and 2 show the hydraulic circuit attached to the automatic transmission 10 with the engagement of the 3-4 clutch 43 and the 2-
The circuit portion related to the release of the 4-brake 45 is extracted and shown. Here, the 2-4 brake 45
As shown in FIG. 1 and FIG.
A piston 68 is provided in the body of the piston 6.
8, the inside of the main body is connected to the release-side oil chamber 67A and the fastening-side oil chamber 6
7B and two rooms. An operating rod 69 is provided integrally with the piston 68, and when the operating rod 69 is extended (moves upward in the drawing), the 2-4 brake 45 is in a fastened state. Conversely, when the operating rod 69 moves for a shortening (moves downward in the figure), the 2-4 brake 45
Is released. That is, the 2-4 brake 45 is
When the hydraulic pressure is supplied to the release-side oil chamber 67A, the release state is established. Alternatively, when the oil pressure of the engagement side oil chamber 67B is discharged, the state becomes the released state. In the drawing, reference numeral 70 denotes a spring for urging the piston 68 to the release side. Actuator 67 for such a 2-4 brake 45
Is known in the art, and therefore, a more detailed description will be omitted.

In FIG. 2, reference numeral 100 denotes a 3-4 clutch line leading to the 3-4 clutch 43.
The other end of the clutch line 100 is a 2-3 shift valve 1
No. 01 is connected to a port a, and a check valve 102 is interposed in the vicinity of the port a. This check valve 102 has a 2-
The arrangement is such that the supply of hydraulic pressure from the 3-shift valve 101 side to the 3-4 clutch 43 is allowed, while the flow in the reverse direction is prohibited.

The 3-4 clutch line 100
Is provided with a bypass line 104 in parallel with the one-way orifice 103, and a bypass valve 105 is interposed in the bypass line 104.

In the 2-3 shift valve 101, an output line 107 connected to the manual valve 106 is connected to a port b of the 2-3 shift valve 101. The output line 107 is such that the manual valve 106 takes the D range position or the 2 range position. In this case, the pump communicates with a main line (not shown) connected to a pump (not shown). And the above 2
The port a and the port b of the -3 shift valve 101 are communicated when the first solenoid valve 108 is turned off.
7, and 2-3 are supplied to the 3-4 clutch 43 through the shift valve 101 and the 3-4 clutch line 100 (3-
4 clutch 43).

One end of a source pressure supply line 108 is connected to the 3-4 clutch line 100 between the check valve 102 and the connection portion of the bypass line 104, and the other end of the source pressure supply line 108 The other end is connected to the port a of the 3-4 shift valve 109. The 3-4 shift valve 109 has a release pressure supply line 111 at port b.
The other end of the release pressure supply line 111 is connected to the release side oil chamber 68A of the 2-4 brake 45.

Port a of the 3-4 shift valve 109
And port b, the second solenoid valve 110 is OFF
When this is done, the line pressure is supplied from the 3-4 clutch line 100 to the release pressure supply line 111 through the original pressure supply line 108, and this line pressure is supplied to the release pressure supply line 111. Through line 111,
The oil is supplied to the release side oil chamber 68A of the 4 brake 45 (2-
Release of 4 brake 45).

The release pressure supply line 111
Is the 2-3 timing valve 11 provided in the middle of the
2 to open and close. That is, the release pressure supply line 111 is connected to the port a and the port b of the 2-3 timing valve 112, and these ports are connected.
The port a and the port b are communicated when the spool 112a moves to the right, and when the spool 112a moves to the left, the communication between the port a and the port b is made. Will be shut off.

The 2-3 timing valve 112 has a left end chamber 112A and a right end chamber 112B with the spool 112a interposed therebetween, and a port c opening to the left end chamber 112A.
Is connected to a first pilot line 113 connected to the 3-4 clutch line 100. On the other hand, a port d opening to the right end chamber 112B is connected to the release pressure supply line 111 (the 2-3 timing valve 112).
A second pilot line 114 connected to the (2-4 brake 45 side) is connected to the first and second pilot lines 113 and 114. Orifices 115 and 116 are interposed in the first and second pilot lines 113 and 114, respectively. I have.

Such a 2-3 timing valve 112
, The release-side oil chamber 6 of the 2-4 brake 45
The hydraulic pressure is supplied to the release-side oil chamber 68A under the balance between the hydraulic pressure in the 8A and the operating pressure of the 3-4 clutch 43. The release timing of the 2-4 brake 45 is adjusted.

In FIG. 2, reference numeral 117 denotes 3-4
2-3 accumulator for buffering when the clutch 43 is engaged
The 2-3 accumulator 117 is connected to the 3-4 clutch line 100 via a one-way orifice 118. In the release pressure supply line 111, the 2-3 timing valve 11
A one-way orifice 119 is interposed in the line on the side of the 2-4 brake 45 relative to 2.

In FIG. 1, reference numeral 120 denotes a control unit constituted by a microcomputer, for example.
U, POM, RAM, etc. are provided. This control
Signals from the sensors 121 to 124 are input to the console unit 120. The sensor 121 detects a vehicle speed. The sensor 122 detects a throttle opening (engine load). The sensor 123 detects the temperature of the hydraulic oil in the hydraulic circuit. The sensor 124 detects the rotation speed of the turbine shaft 27.

The control unit 120 generates a shift control signal based on the vehicle speed and the throttle opening, and the shift control signal is generated by the first and second solenoid valves 1 and 2.
It is sent to various solenoid valves in the hydraulic circuit such as 08 and 110. As is known, the shift control signal is generated by comparing the detected vehicle speed and the detected throttle opening with an upshift line or a downshift line in a shift map (not shown).

The upshift control from the second speed to the third speed will be described below. For convenience of explanation, the contents of the circuit shown in FIG. 1 will be described first. The same elements as those included in the circuit of FIG. 2 among the elements shown in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. Will be described only.

The apply line 130 of the 2-4 brake 45 is connected to the fastening side oil chamber 67B, and the other end of the apply line 130 is connected to the port a of the 1-2 shift valve 131. An orifice 133 is provided in the middle of the apply line 130. The 1-2 shift valve 131 is provided by the O of the third solenoid valve 132.
N, operated by OFF, the third solenoid valve 1
When the port 32 is turned off, the port a and the drain port
B, and conversely, the third solenoid valve 1
When the switch 32 is turned on, the communication between the port a and the drain port b is cut off. Therefore, when the third solenoid valve 132 is turned off, 2-4
The oil pressure in the engagement side oil chamber 67B of the brake 45 is discharged from the drain port b of the 1-2 shift valve 131 through the apply line 130.

The apply line 130 is provided with a bypass line 134 for bypassing the orifice 133, and a 3-2 timing valve 135 is interposed in the bypass line 134. That is, the bypass line 134 is connected to the 2-4 brake 45 side line 1
34a is connected to the port a of the 3-2 timing valve 135, and the 1-2 shift valve 131 side line 134b is connected to the port b of the 3-2 timing valve 135. An orifice 136 is provided on the 2-4 brake side line 134a, and a one-way orifice 137 is provided on the 1-2 shift valve side line 134b.

The 3-2 timing valve 135 is operated by turning on and off the fourth solenoid valve 138. When the fourth solenoid valve 138 is turned off, the ports a and b communicate with each other. Conversely, when the fourth solenoid valve 138 is turned on, the port a is disconnected from the port b while being connected to the drain port c. Therefore, the fourth
When the solenoid valve 138 is turned on, 2-4
The hydraulic pressure of the engagement side oil chamber 67B of the brake 45
The fuel is discharged from the drain port b of the 3-4 timing valve 135 through the brake side bypass line 134a.

FIG. 1 shows the state when the second solenoid valve 110 of the 3-4 shift valve 109 is turned on. When the second solenoid valve 110 is turned on, the 3-4 shift valve is shifted. Port of valve 109
The port c and the port d are communicated. And this port c
3-4 clutch line 110 is connected to
The output line 107 is connected to the gate d. Therefore, when the second solenoid valve 110 is turned on, the output line 107 passes through the path formed by the port c and the port d of the 3-4 shift valve 109 and the 3-4 clutch line 110, and then passes through the path formed by the 3-4 clutch line 110. -4 clutch 43 is supplied with hydraulic pressure.

In the shift control from the second speed to the third speed, different control is performed depending on the oil temperature when the hydraulic oil is at normal temperature and when it is at low temperature. Incidentally, the ON / OFF combination patterns of the solenoid valves 108 and the like in the second speed state are as follows. Solenoid pattern in 2nd speed state (2nd speed pattern) 1st solenoid valve 108 (ON) 2nd solenoid valve 110 (ON) 3rd solenoid valve 132 (ON) 4th solenoid valve 138 (OFF)

The ON / OFF combination patterns of the solenoid valves 108 and the like in the third speed state are as follows. Solenoid pattern in 3rd speed state (3rd speed pattern) 1st solenoid valve 108 (OFF) 2nd solenoid valve 110 (OFF) 3rd solenoid valve 132 (ON) 4th solenoid valve 138 (OFF) 3 When the high speed solenoid pattern is taken, the engagement of the 3-4 clutch 43 and the release of the 2-4 brake 45 are performed in the state of FIG.

An example of the shift control from the second speed to the third speed will be described with reference to flowcharts shown in FIGS. In FIG. 4, in step S1 (hereinafter, step numbers are denoted by reference numerals "S"), it is determined whether or not there is a 2-3 shift command.
Proceeding to 2, it is determined whether the operating oil is higher than a predetermined temperature. When it is determined as YES in S2, it is determined that the oil temperature is in the normal temperature state, and the process proceeds to S3 to perform the control for the normal temperature. That is, the solenoid pattern is changed to the third speed pattern.

In S2, when the determination is NO, it is determined that the oil temperature is in a low temperature state, and the process proceeds to S4.
After performing the low-temperature control described later (FIG. 5), the routine proceeds to S3, where the solenoid pattern is changed to the third-speed pattern.

FIG. 5 shows the contents of the low-temperature control in S4. In this low-temperature control, first, in step S10, the second-speed solenoid pattern is changed to the low-temperature solenoid pattern shown below. Low temperature solenoid pattern First solenoid valve 108 (OFF) Second solenoid valve 110 (ON) Third solenoid valve 132 (ON) Fourth solenoid valve 138 (OFF) When this low temperature solenoid pattern is taken, 1
The engagement of the 304 clutch 43 is started in the mode shown in FIG.
Since the third solenoid valve 132 is ON and the fourth solenoid valve 138 is OFF, the 2-4 brake 45 is not released.

Then, in the next S11, it is determined whether or not the 3-4 clutch 43 has started engaging.
The start of engagement of the 3-4 clutch 43 is, as is known,
It is detected from a change in the rotation speed of the turbine shaft 27.
If it is determined YES in S11, S
Proceeding to 12, the third solenoid valve 132 is turned off
And the release of the 2-4 brake 45 is started. Then, in step S11, the third solenoid valve 132
When a predetermined time T ₀ elapses after turning OFF (S1
(3, S14), the process proceeds to S3 (FIG. 4), and the solenoid pattern is changed to the third speed pattern.

The embodiment of the present invention has been described above.
When it is necessary to increase the release speed of the four brakes 45, for example, when the change in the number of revolutions of the turbine shaft 27 is large, the third solenoid valve 132 is turned off in step S12 (FIG. 5) at the same time. 4th
The drain valve b of the 3-4 timing valve 135 may be opened by switching the solenoid valve 138 to ON.

[0050]

As is apparent from the above description, according to the present invention, even when the oil temperature is low, it is possible to reliably prevent a temporary decrease in the operating pressure of one frictional fastening element. Therefore, it is possible to reliably prevent the operation change timing between one friction fastening element and another friction fastening element from being affected by the oil temperature.

[Brief description of the drawings]

FIG. 1 shows a hydraulic circuit of an automatic transmission at a low oil temperature.
FIG. 3 is a circuit diagram extracting and showing circuit portions related to -3 upshift.

FIG. 2 shows a hydraulic circuit of an automatic transmission at a low oil temperature;
FIG. 3 is a circuit diagram extracting and showing circuit portions related to -3 upshift.

FIG. 3 is an overall configuration diagram of the automatic transmission.

FIG. 4 is a flowchart showing an example of shift control in a 2-3 upshift.

FIG. 5 is a flowchart showing an example of a 2-3 upshift speed change control at a low oil temperature.

FIG. 6 is a conceptual diagram showing a basic configuration of the present invention.

[Explanation of symbols]

Reference Signs List 10 automatic transmission 43 3-4 clutch (one friction engagement element) 45 2-4 brake (other friction engagement element) 67B engagement-side oil chamber 108 first solenoid valve 109 3-4 shift valve (source pressure supply) Timing adjusting means) 110 second solenoid valve 112 2-3 timing valve (timing valve) 120 control unit 130 apply line 131 1-2 shift valve 135 3-4 timing valve

Continuation of the front page (56) References JP-A-64-69851 (JP, A) JP-A-2-80854 (JP, A) JP-A-2-203074 (JP, A) JP-A-62-106156 (JP, A) JP-A-2-97761 (JP, A) JP-A-2-42251 (JP, A) JP-A-2-42259 (JP, A) JP-A-61-45157 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (3)

(57) [Claims] A hydraulic circuit of an automatic transmission adapted to obtain a desired gear by changing a combination of engagement or disengagement of a plurality of frictional engagement elements based on a gearshift command signal from a control unit. A first valve that opens and closes a hydraulic pressure supply path that supplies oil pressure to the frictional engagement element, and a second valve that opens and closes an exhaust pressure path that discharges oil pressure in the frictional element
Wherein the first and second valves are opened and closed based on a shift command signal from the control unit, wherein a hydraulic pressure is applied to the plurality of frictional engagement elements. One frictional engagement element that performs an engagement operation when supplied, and a piston that separates the engagement-side oil chamber and the release-side oil chamber performs an engagement operation or a release operation based on a difference in force received from the oil pressure in each of these oil chambers. And a hydraulic pressure supply timing for supplying a hydraulic pressure to the release-side oil chamber of the other frictional engagement element in response to the operating pressure of the one frictional engagement element. A timing valve, an oil temperature detecting means for detecting an oil temperature in the hydraulic circuit, an engagement start detecting means for detecting an engagement start of the one friction engagement element, and a variable generated by the control unit. Shift command discriminating means for discriminating that the command is a shift command to a shift speed accompanied by engagement of the one frictional engagement element and release of the other frictional engagement element; Upon receiving a signal from the detecting means, the shift command generated by the control unit is a shift command to a shift speed with engagement of the one friction engagement element and release of the other friction engagement element, Shift control mode switching means for setting a first shift control mode when the oil temperature is high and setting a second shift control mode when the oil temperature is low, according to the level of the oil temperature in the hydraulic circuit;
Wherein the first shift control mode controls the hydraulic pressure supply timing of the other frictional engagement element to the release-side oil chamber by the timing valve. The second shift control mode includes the engagement mode. In response to a signal from the start detecting means, when the one frictional engagement element starts engaging, the second valve provided in the exhaust pressure path connected to the engagement side oil chamber of the other frictional engagement element A shift control device for an automatic transmission, wherein 2. The friction engagement device according to claim 1, further comprising: a second valve provided in an exhaust path connected to an engagement-side oil chamber of the another friction engagement element; A shift control device for an automatic transmission, further comprising: a hydraulic discharge speed changing unit configured to change a speed at which a hydraulic pressure of an engagement side oil chamber of the element is discharged. 3. The method according to claim 1, wherein the fastening of the one friction fastening element is performed by supplying hydraulic pressure, and the fastening of the one friction fastening element is performed by discharging hydraulic pressure. The other frictional fastening element is engaged by supplying hydraulic pressure to the engagement-side oil chamber in a state where the hydraulic pressure in the release-side oil chamber is released. Is released when hydraulic pressure is supplied to the release-side oil chamber regardless of hydraulic supply / discharge to / from the engagement-side oil chamber, and the release of the hydraulic pressure is performed regardless of supply / discharge of hydraulic pressure to / from the release-side oil chamber. A shift control device for an automatic transmission, wherein the shift control device is set to be performed even when the hydraulic pressure of the engagement-side oil chamber is discharged.