JP3454523B2 - Automatic transmission clutch control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch control device for an automatic transmission. 2. Description of the Related Art A conventional clutch control device for an automatic transmission is disclosed in EPC Application No. 0339663A1. In the automatic transmission shown in this figure, it is necessary to disengage the engaged clutch in the fourth speed and release the engaged brake in the fourth speed during the 4-3 shift. It is necessary to execute the engagement of the clutch and the release of the brake at a predetermined timing. If the release of the brake is performed relatively earlier than the engagement of the clutch, a neutral state occurs and so-called idling of the engine occurs, and conversely, the engagement of the clutch is performed relatively earlier than the release of the brake. Then, the brake and the clutch are both engaged (interlocked), and a large shift shock is generated. Therefore, in the above patent application,
By adjusting the oil pressure of the clutch during the 4-3 shift,
Feedback control is performed such that the input rotational acceleration matches the target value. In this case, there is a time delay from when the electronic control device outputs a signal for engaging the clutch until the clutch engaging operation is actually started. The time delay is the time from when the supply of the hydraulic pressure to the oil chamber of the clutch is started to when the piston moves toward the clutch plate and comes into contact with the piston to actually apply the pressing force. In order to cope with this time delay, the above-mentioned time delay is assumed in advance, and the clutch engagement signal is output earlier by this time. Since the time delay varies among the units of the automatic transmission, and even in the same unit, the time delay varies according to the operating conditions. Therefore, the preset time delay is corrected by learning control. [0003] In the prior art as described above, special control is required in order to cope with a delay in the engagement time of the clutch. That is, it is necessary to output the clutch engagement command signal earlier by a predetermined time, and to correct the value of the time delay by learning control. For this reason, an extra program is required in the electronic control unit, and a large amount of data needs to be stored. An object of the present invention is to solve such a problem. According to the present invention, a low oil pressure is applied to the oil chamber of the clutch in advance, and then the fact that the engine rotational speed is just before the value corresponding to the rotational speed of the shift stage is realized. The above problem is solved by increasing the oil pressure of the oil chamber of the clutch and engaging the clutch as the timing to be engaged. That is, a clutch control device for an automatic transmission according to the present invention (corresponding to claim 1 ) includes a shift valve (52), a shift solenoid valve (54) for controlling switching of the shift valve, a timing valve (58), A timing solenoid valve (60) for controlling switching of the timing valve, an accumulator (91), an electronic control unit (74), and an accumulator control pressure oil passage (9) according to a signal from the electronic control unit.
An accumulator control solenoid valve (92) capable of outputting an accumulator control pressure is provided in 3), and the accumulator has an adjustment pressure chamber (97) and a back pressure chamber (98) partitioned on both sides by a piston (95). ), The adjusting pressure chamber of the accumulator and the oil chamber (68) of the clutch are connected by a first oil passage (71), and the second oil passage is connected to the second oil passage through an orifice (90). An oil passage (70) is connected, and the shift valve can be switched between an engagement side position and a release side position according to the oil pressure from the shift solenoid valve, and when the shift valve is in the engagement side position, the line pressure is increased. The oil passage (73) is connected to the second oil passage, and is configured to drain the second oil passage at the release side position. The timing valve is configured to perform timing between the communication position and the drain position. Switching is possible in accordance with the oil pressure from the solenoid valve, and in the communication position, the accumulator control pressure oil passage is communicated with a back pressure oil passage (94) communicating with the back pressure chamber of the accumulator. The shift solenoid valve is configured to drain the oil passage, and the shift solenoid valve outputs a signal for positioning the shift valve to the engagement side or the release side by a signal from the electronic control device when the operation state is set in advance, The timing solenoid valve outputs a hydraulic pressure for switching the timing valve from the drain position to the communication position by a signal output from the electronic control device a predetermined time after the electronic control device outputs a signal for switching from the engagement side to the release side to the shift solenoid valve. The accumulator then adjusts approximately one of the adjustment pressure chambers while its piston moves. Low hydraulic pressure of,
When this low oil pressure acts on the oil chamber of the clutch, the piston is moved from the initial stop position on the clutch release position side to the operation start position where the pressing force is applied to the clutch plate (67), but the piston is moved toward the clutch disengagement position. The electronic control unit is set so that the clutch is not started to be engaged in proportion to the force of the return spring (66) to be pushed, and the electronic control unit determines that the engine rotational speed is immediately before the value corresponding to the rotational speed of the shift speed. And outputting a signal to the shift solenoid valve to position the shift valve on the engagement side. In addition, the code | symbol in a parenthesis shows the corresponding member of 1st Example mentioned later. According to the first aspect of the invention, when the shift valve is at the release side position, the first oil passage is drained,
Since no oil pressure acts on the oil chamber of the clutch, the piston of the clutch is pushed by the return spring to the initial stop position, and the clutch plate is released. When a shift signal is output from the electronic control unit in this state, the shift solenoid valve is operated by this, and the shift valve is switched to the engagement side. This allows the second
The line pressure acts on the oil passage, and a hydraulic pressure is also generated in the first oil passage. This hydraulic pressure is a low hydraulic pressure adjusted by the accumulator. This low oil pressure causes the clutch piston to
This is set to a value that moves the clutch plate to a position immediately before the pressing force acts on the clutch plate. In this state, when a predetermined time elapses and the rotational speed of the engine comes to just before the rotational speed appropriate for the gear after the shift, the electronic control unit switches the timing solenoid valve and switches the timing valve to the communication side. Thereby, the accumulator control pressure oil passage is connected to the back pressure chamber of the accumulator, and the hydraulic pressure of the first oil passage rises. Since the oil chamber of the clutch is filled with oil,
Simultaneously with the switching of the timing valve, the piston applies a pressing force to the clutch plate, and the clutch is engaged. Since the oil chamber of the clutch is filled with oil, there is no time delay until the engagement is started, and the clutch can be engaged at the set timing. In the above description of the present specification, the term clutch is used in addition to a normal one that connects two rotating members, and one in which one member is fixed, that is, a so-called brake, has a basic function. Since this is the same, this shall be included. FIG. 2 shows a forward 4-speed reverse 1 with overdrive.
1 shows a power transmission mechanism of a high-speed automatic transmission as a skeleton diagram. The power transmission mechanism includes an input shaft 13 to which torque from an engine output shaft 12 is transmitted via a torque converter 10;
Output shaft 14, which transmits driving force to the final drive device,
A first planetary gear set 15, a second planetary gear set 16, a reverse clutch 18, a high clutch 20, a low clutch 24, a low and reverse brake 26, a band brake 28,
And a low one-way clutch 29. In addition,
The torque converter 10 has a lock-up clutch 11 built therein. The first planetary gear set 15 includes a sun gear S1 and
The planetary gear set 16 includes an internal gear R1 and a carrier PC1 that supports a pinion gear P1 that meshes with both gears S1 and R1 at the same time.
And a carrier PC2 that supports a pinion gear P2 that meshes with the carrier PC2. The carrier PC1 can be connected to the input shaft 13 via the high clutch 20, and the sun gear S1 can be connected to the input shaft 13 via the reverse clutch 18. The carrier PC1 can also be connected to the internal gear R2 via the low clutch 24. The sun gear S2 is always connected to the input shaft 13,
Further, the internal gear R1 and the carrier PC2 are always connected to the output shaft 14. The low and reverse brake 26 can fix the carrier PC1,
The band brake 28 can fix the sun gear S1. The low one-way clutch 29 rotates the carrier PC1 forward (rotation in the same direction as the engine output shaft 12).
Is arranged in a direction that allows but does not allow reverse rotation (rotation in the opposite direction to normal rotation). The automatic transmission described above operates the clutches 18, 20 and 24 and the brakes 26 and 28 in various combinations to operate the components (S1, S2, R1, R2, PC1, PC1, And PC2)
Of the input shaft 1 can be changed.
The rotation speed of the output shaft 14 with respect to the rotation speed 3 can be variously changed. By operating the clutches 18, 20 and 24 and the brakes 26 and 28 in a combination as shown in FIG. 3, four forward speeds and one reverse speed can be obtained. In FIG. 3, the symbols .DELTA. Indicate operating clutches and brakes, and .alpha.1 and .alpha.2 are ratios of the number of teeth of the sun gears S1 and S2 to the number of teeth of the internal gears R1 and R2, respectively. 14 is a ratio of the rotation speed of the input shaft 13 to the rotation speed of the input shaft 14. FIG. 1 shows a hydraulic circuit for controlling the operation of the low clutch 50. This hydraulic circuit includes a 3-4 shift valve 52, a shift solenoid valve 54, a timing valve 58, a timing solenoid valve 60, a one-way orifice 90, an accumulator 91, an accumulator control solenoid valve 92, and the like. Low clutch 5
0 has a drum 64, a piston 56, a return spring 66, and a clutch plate 67. When hydraulic pressure acts on the oil chamber 68, the piston 65 moves to the left in FIG. 1 against the force of the return spring 66, and applies a pressing force to the clutch plate 67, which can be brought into the engaged state. . A play is provided in the stroke of the piston 65, and the piston 65 can actually apply a pressing force to the clutch plate 67 after performing the stroke for the play. The 3-4 shift valve 52 can be switched between a fourth speed position (release position) and a third speed position (engagement position) in accordance with the hydraulic pressure acting from the shift solenoid valve 54 via the oil passage 69. . 3-4 shift valve 52
Connects the second oil passage 70 to the drain port at the fourth speed position. Further, the 3-4 shift valve 52 connects the second oil passage 70 with an oil passage 73 to which the line pressure is supplied at the third speed position. The shift solenoid valve 54 can switch between a state in which oil pressure is output to the oil passage 69 and a state in which the oil pressure in the oil passage 69 is drained in response to an electric signal from the electronic control unit 74. The timing valve 58 can switch between a communication position and a drain position according to the oil pressure of the oil passage 76. In the communication position, the timing valve 58 is connected to the back pressure oil passage 94 and the accumulator control pressure oil passage 9.
3 while the back pressure oil passage 94 is drained at the drain position. The timing solenoid valve 60 can switch between a state in which oil pressure is output to the oil passage 76 and a state in which the oil pressure in the oil passage 76 is drained by an electric signal from the electronic control device 74. The accumulator 91 has a cylinder 94, a piston 95, and a spring 96. The cylinder 94 is adjusted by the piston 95 to the pressure adjusting chamber 9.
7 and a back pressure chamber 98. A first oil passage 71 is connected to the adjustment pressure chamber 97, and a back pressure oil passage 94 is connected to the back pressure chamber 98.
Is connected. The first oil passage 71 is also connected to the oil chamber 68 of the low clutch 50. Further, the first oil passage 7
1 is connected to the second oil passage via a one-way orifice 90. The one-way orifice 90 is arranged so as to generate a throttle effect when oil flows from the second oil passage 70 to the first oil passage 71. Accumulator control solenoid valve 9
2 can control the hydraulic pressure of the accumulator control pressure oil passage 93 in accordance with a signal from the electronic control device 74 as described later. Next, the operation of this embodiment will be described.
First, the shift from the fourth speed to the third speed will be described. 4th
In the high speed state, the timing solenoid valve 60
6 and the timing valve 58 is at the drain position. The shift solenoid valve 54 outputs oil pressure to the oil passage 69, and the 3-4 shift valve 52 is in the fourth speed position.
Therefore, the second oil passage 70 is drained. Therefore, the first oil passage 71 is also drained, no oil pressure acts on the oil chamber 68 of the clutch 50, the piston 65 does not move to the engagement side, and the low clutch 50 is in the released state.
When the electronic control unit 74 determines from the fourth speed state that the operating condition is such that the shift from the fourth speed to the third speed should be performed based on the throttle opening signal, the vehicle speed signal, and the like, the shift solenoid valve 54 is electrically operated. When the signal is output, the shift solenoid valve 54 switches to a state in which the oil pressure in the oil passage 69 is drained. This switches the 3-4 shift valve 52 to the third speed position. Therefore, the oil passage 73 communicates with the second oil passage 70. When the oil passage 73 communicates with the second oil passage 70, the line pressure of the oil passage 73 is supplied to the second oil passage 70.
The hydraulic pressure supplied to the second oil passage 70 is supplied to the one-way orifice 90.
Is supplied to the first oil passage 71 via the The oil pressure in the first oil passage 71 acts on the adjustment pressure chamber 97 of the accumulator 91 to move the piston 95. Since the force of the spring 96 is set to be very small, the oil pressure in the first oil passage 71 is kept at a very low value while the piston 95 is moving. The value of the oil pressure is set so as to balance the force of the return spring 66 when the piston 65 of the clutch 50 is moved to a position immediately before the pressing force acts on the clutch plate 67. Accordingly, no pressing force acts on the clutch plate 67 while the piston 95 of the accumulator 91 is moving. In this state, when the engine rotation speed increases and immediately before the rotation speed corresponding to the third speed, the electronic control unit 74 outputs an electric signal to the timing solenoid valve 60 to drain the oil pressure in the oil passage 76. Therefore, the timing valve 58 is switched to the communication side, and the accumulator control pressure oil passage 93 communicates with the back pressure oil passage 94. Therefore, the accumulator control pressure acts on the back pressure chamber 98. Since the accumulator control pressure is set to a high value (this oil pressure can be controlled as a function of time by the accumulator control solenoid valve 92), the oil pressure in the adjustment pressure chamber 97 increases accordingly. The oil pressure acts on the oil chamber 68 of the clutch 50 via the first oil passage 71. As a result, the piston 65 exerts a pressing force on the clutch plate 67, and the low clutch 50 is engaged. Since the piston 65 of the low clutch 50 has moved to a position immediately before applying a pressing force to the clutch plate 67, the low clutch 50 is engaged after an electric signal is output from the electronic control unit 74 to the timing solenoid valve 60. The time until is very short. Therefore, even if no special control is performed, the low clutch 50 due to a temperature change or a change over time can be used.
, The variation in the engagement timing is reduced, and the fluctuation of the shift shock can be reduced. Further, since the engagement timing of the low clutch 50 does not change, it is not necessary to set a long drag time (a state in which the clutch is slid in a half-clutch state) of the band brake 28, and the durability of the band brake 28 can be improved. Next, the shift from the third speed to the fourth speed will be described. When the operating condition for shifting from the third speed state to the fourth speed state is reached, the electronic control unit 74 outputs an electric signal to the shift solenoid valve 54, and the shift solenoid valve 54 outputs a hydraulic pressure to the oil passage 69. With this, 3-
The 4-shift valve 52 switches to the fourth speed position, and the second oil passage 70 communicates with the drain port. Therefore, the oil pressure in the oil chamber 68 of the low clutch 50 is drained through the first oil passage 71, the one-way orifice 90, the second oil passage 70, and the 3-4 shift valve 52. The state of decrease in the oil pressure of the first oil passage 71 during this time can be controlled by the accumulator 96 and the accumulator control solenoid valve 92. As a result, the low clutch 50 is released, and at the same time, the band brake 28 (not shown in FIG. 1) is engaged to realize the fourth speed state. During or after the low clutch 50 is released, the timing solenoid valve 6
0 is switched by an electric signal from the electronic control unit 74, and the oil pressure is output to the oil passage 76. This switches the timing valve 58 to the drain position. As described above, according to the present invention, a low hydraulic pressure is applied to the piston of the clutch in advance to move the clutch plate to the engagement start position.
For your information, the force in the direction of release of the return spring and fishing
Do not start the fastening operation at the same time.
The rotational speed is just before the value corresponding to the rotational speed of the gear.
When to actually engage the clutch
Therefore, since the clutch engagement is commanded, the clutch engagement can be started immediately at a desired timing, and the shift timing can be accurately controlled.
If not required the construction of a special electronic control system for the
The above effect can be obtained .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a first embodiment of the present invention. FIG. 2 is a diagram showing a skeleton diagram of the automatic transmission. FIG. 3 is a diagram showing a combination of elements acting at each shift speed of the automatic transmission. [Description of Signs] 50 Low clutch 52 3-4 shift valve (shift valve) 54 shift solenoid valve 58 timing valve 60 timing solenoid valve 67 clutch plate 68 oil chamber 70 second oil passage 71 first oil passage 73 line pressure oil passage 74 Electronic control unit 90 Orifice 91 Accumulator 92 Accumulator control solenoid valve 93 Accumulator control pressure oil passage 95 Piston 97 Adjusting pressure chamber 98 Back pressure chamber

Continuation of the front page (56) References JP-A-2-261960 (JP, A) JP-A-61-109941 (JP, A) JP-A-3-41258 (JP, A) JP-A-3-48063 (JP, A) , A) JP-A-63-289359 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 61/04

Claims (1)

(57) [Claim 1] A clutch which is engaged by applying a pressing force to a clutch plate by moving a piston against a force of a return spring by a hydraulic pressure acting on an oil chamber. A clutch control device for an automatic transmission having a shift valve, a shift solenoid valve for controlling switching of the shift valve, a timing valve, a timing solenoid valve for controlling switching of the timing valve, an accumulator, an electronic control device, An accumulator control solenoid valve capable of outputting an accumulator control pressure to an accumulator control pressure oil passage in response to a signal from the electronic control unit.The accumulator has a regulating pressure chamber and a back pressure which are respectively partitioned on both sides of the accumulator by a piston. The accumulator has an adjustment pressure chamber and a The first oil passage is connected to the oil chamber of the switch, the second oil passage is connected to the first oil passage via an orifice, and the shift valve is engaged according to the hydraulic pressure from the shift solenoid valve. It is possible to switch between the side position and the release side position, connect the line pressure oil passage to the second oil passage when in the engagement side position, and drain the second oil passage in the release side position. The timing valve can be switched between a communication position and a drain position according to the hydraulic pressure from the timing solenoid valve, and in the communication position, the accumulator control pressure oil passage communicates with the back pressure chamber of the accumulator. It is configured to communicate with the back pressure oil passage that is being operated, and to drain the back pressure oil passage at the drain position, and the shift solenoid valve is in the preset operating state If the electronic control unit outputs a signal to position the shift valve on the engagement side or the release side by a signal from the electronic control unit, the timing solenoid valve outputs a signal from the electronic control unit to the shift solenoid valve for switching from the engagement side to the release side to the shift solenoid valve. After a predetermined time, a signal output from the electronic control unit outputs a hydraulic pressure for switching the timing valve from the drain position to the communication position, and the accumulator adjusts the piston while the piston is moving. When the low oil pressure acts on the oil chamber of the clutch, the piston is moved from the initial stop position on the clutch release position side to the operation start position where the pressing force is applied to the clutch plate, but the return spring presses the piston toward the clutch release position. The size is set so that the clutch will not start engaging with the force. The electronic control unit outputs a signal to the shift solenoid valve so as to position the shift valve on the engagement side when the engine rotation speed is immediately before the value corresponding to the rotation speed of the shift speed. Transmission clutch control device.