JP2798408B2 - Control device for lock-up clutch - Google Patents

Description

The present invention relates to a lock-up clutch control device.

(B) Conventional technology A conventional lock-up clutch control device is disclosed, for example, in Japanese Patent Application Laid-Open No. 60-241570. The torque converter of the automatic transmission shown therein has a lock-up clutch, and this lock-up clutch is completely engaged at two or more shift speeds. When shifting from a state in which a lock-up clutch of a predetermined gear is engaged to a state in which a lock-up clutch of another gear is engaged, the lock-up clutch is temporarily released. That is, the lock-up clutch is released a predetermined time after the shift command signal is output, and the lock-up clutch is re-engaged a predetermined time after this. The shift is completed while the lock-up clutch is released. This is intended to alleviate the shock during shifting.

(C) Problems to be Solved by the Invention However, in the conventional lock-up clutch control device as described above, since the lock-up clutch is released and the fluid transmission state is established at the time of gear shifting, the engine speed increases and the engine speed increases. However, there is a problem that the rotational speed of the engine is reduced in the refastening portion, and a shock is generated accordingly. In addition, the fuel consumption increases because the engine rotation speed increases, even during the shift. Japanese Patent Application Laid-Open No. 63-6746 discloses a solution to this problem.
There is one shown in Japanese Patent Publication No. That is, in this example, while the automatic transmission is performing a shift in the lock-up region, the inertia phase detecting means detects the inertia phase during the shift, and in the inertia phase, the slip amount of the torque converter is reduced to zero. And a maximum value, that is, a state between the lock-up state and the converter state (ie, a half-clutch state) by the slip control means. This prevents the converter from suddenly changing from the lock-up state to the converter state, reducing the change in the transmission state to reduce the accompanying shock.Also, even if the shift timing is shifted due to the change in the hydraulic pressure that governs the shift, it will always slip. Since the shift is performed during control, the peak torque during shifting and the engine It is possible to suppress the racing, it is capable of also reduces shock due to these.

However, the one disclosed in Japanese Patent Application Laid-Open No. 63-67461 has the following problems. In other words, in the case of an upshift, since the engine speed is reduced after the shift is completed compared to before the speed change, the speed difference is reduced so that the engine speed is not increased during the speed change as much as possible to reduce the shock, On the other hand, in the case of a downshift, since the engine speed is increased after the shift is completed as compared to before the shift, the speed difference is increased so that the engine speed is increased faster, and the response is improved. However, the method disclosed in Japanese Patent Application Laid-Open No. 63-67461 does not disclose how to set a target value of a speed difference between the engine rotation speed and the turbine rotation speed during gear shifting. There is a problem that it is not possible to alleviate the shock at the time and to improve the responsiveness at the time of the downshift.
An object of the present invention is to solve such a problem.

(D) Means for Solving the Problems According to the present invention, the set value of the speed difference between the target engine rotation speed and the turbine rotation speed at the time of gear shifting is set to a smaller value during an upshift than during a downshift. This solves the above problem. That is, the operating state of the lock-up clutch that can connect the pump impeller side and the turbine runner side of the fluid transmission device is controlled by the solenoid, and the lock-up operation region in which the lock-up clutch is fully engaged is in two or more shift speeds. When shifting from a lock-up operation region of a predetermined gear position to a lock-up operation region of another gear position, a half-clutch means during shifting that temporarily sets the lock-up clutch to a half-clutch state during gear shifting is set. The half-clutch means during shifting is configured such that the difference between the engine rotation speed detected by the engine rotation speed sensor and the turbine rotation speed detected by the turbine rotation speed sensor becomes a preset value. A lock-up clutch configured to control the operation of the solenoid. In the control device, the setting value, the upshift is obtained and characterized in that it is set smaller than that during the downshift.

(E) Operation In the case of an upshift, since the engine speed is reduced after the shift is completed compared to before the speed change, the engine speed must be prevented from rising as much as possible. Since the set value of the difference is set small at the time of the upshift, an increase in the engine speed is suppressed, and the shift shock is reduced. On the other hand, in the case of a downshift, the engine speed is increased after the shift is completed than before the shift, so the engine speed must be increased faster. As a result, the engine speed increases quickly and the responsiveness improves.

(F) Embodiment FIG. 2 shows an embodiment of the present invention. Torque converter 10
Has a lock-up clutch 18 in addition to the pump impeller 12, the turbine runner 14, and the stator 16. An apply chamber 20 in which the pump impeller 12, the turbine runner 14, and the like are arranged is formed on the right side of the lock-up clutch 18 in the figure, and a release chamber 22 is formed on the left side of the lock-up clutch 18 in the figure. An oil passage 24 is connected to the apply chamber 20, and an oil passage 26 is connected to the release chamber 22. The lock-up clutch 18 has a fading 30 that comes into contact with the friction surface of the cover 28 of the torque converter 10. The supply state of the hydraulic pressure to the oil passage 24 and the oil passage 26 is controlled by a lock-up control valve 32. The lock-up control valve 32 has a spool 34, a sleeve 36,
It has a plug 38 and a spring 40. The oil passages 42, 44, 46, and 46 other than the oil passages 24 and 26 described above.
48 and the oil passage 50 are also connected as shown. Oilway 42
Is supplied with a constant pressure from a torque converter relief valve 52. It should be noted that the torque converter relief valve 52 performs a pressure regulation operation using the oil pressure of an oil passage 54 to which oil pressure is supplied from a pressure regulator valve (not shown). The oil passage 44 is connected to an oil cooler 56, and the oil leaving the oil cooler 56 is used for lubrication. A constant pressure regulated by a pressure regulating valve (not shown) is supplied to the oil passage 50. Oil passage 46 branched via oil passage 50 and orifice 56
Is connected to the lock-up solenoid 58. The lock-up solenoid 58 includes a plunger 62 that closes the opening 60 of the oil passage 46 in a non-energized state. The energized state of the lock-up solenoid 58 is controlled by a duty ratio by a signal from the control unit 64. That is, the lock-up solenoid 58 is repeatedly turned on and off at a predetermined cycle, and opens the opening 60 in accordance with the ratio of the on-time, thereby adjusting the oil pressure of the oil passage 46 so as to be inversely proportional to the on-time. Signals from an engine speed sensor 66, a turbine speed sensor 68, a throttle opening sensor 70, and a vehicle speed sensor 72 are input to the control unit 64, and the control unit 64 uses the signals as described below based on these signals. The operation of the lock-up solenoid 58 is controlled.

Next, the operation of this embodiment will be described. First, control of the disengaged state, half-clutched state, and fully engaged state of the lock-up clutch 18 will be described.

The release state of the lock-up clutch 18 is realized as follows. That is, the duty ratio of the lock-up solenoid 58 is set to 0, and the opening 60 is completely closed by the plunger 62. For this reason, the same oil pressure as the oil passage 50 is generated in the oil passage 46, and this acts on the left end of the spool 34 of the lock-up control valve 32. As a result, the spool 34 is in the state shown in the figure, and the oil pressure in the oil passage 42 is supplied to the release chamber 22 through the oil passage 26, and the oil pressure in the release chamber 22 is further applied to the friction surface of the cover 28 and the facing 30.
Flows into the apply chamber 20 side through the gap between them, returns to the lock-up control valve 32 through the oil passage 24, and is then discharged to the oil passage 44. That is, the hydraulic pressure is
The air is supplied from 26 to the release chamber 22 and then discharged from the apply chamber 20 to the oil passage 24. Therefore, the release chamber 22 and the oil pressure are equal to the oil pressure of the apply chamber 20 (strictly speaking, since the apply chamber 20 side is on the downstream side, the apply chamber 20 side is slightly lower due to a flow path loss). As a result, the lock-up clutch 18 is released. That is, the torque converter 10 enters a torque converter state in which the torque is transmitted only through the fluid.

When controlling the lock-up clutch 18 to the half-clutch state from the above state, the following operation is performed. That is, when the duty ratio given to the lock-up solenoid 58 from the control unit 64 gradually increases, oil is discharged from the opening 60 in accordance with this duty ratio and the oil passage 46
Oil pressure decreases. Therefore, the hydraulic pressure acting on the left end of the spool 34 of the lock-up control valve 32 decreases, and the spool 34 and the plug 38 move leftward in the drawing. When the spool 34 and the plug 38 move to the left by a predetermined amount, the oil passage 26 slightly communicates with the drain port 72, and at the same time, the oil passage 42 communicates with the oil passage 24. Since the oil pressure of the oil passage 26 is fed back to the right end of the plug 38 via the oil passage 48, the lock-up control valve 32 is in a pressure regulating state, and the oil pressure of the oil passage 26 is
The pressure is adjusted in accordance with the hydraulic pressure acting on the left end of the spool 34 from. That is, in this state, hydraulic pressure is supplied to the torque converter 10 from the oil passage 24 to the apply chamber 20,
The hydraulic pressure in the apply chamber 20 is covered by the lock-up clutch 18
Into the release chamber 22 through the gap between
Will be exhausted. The oil pressure in the oil passage 26 is
, Ie, a hydraulic pressure that is adjusted in inverse proportion to the duty ratio of the lock-up solenoid 58. Since the oil pressure on the release chamber 22 side is lower than the oil pressure on the apply chamber 20 side, the facing 30 of the lock-up clutch 18 is pressed against the friction surface of the cover 28. The force for pressing the lock-up clutch 18 is controlled by the lock-up solenoid 58 as described above.

Next, the duty ratio of the lock-up solenoid 58 is set to 10
At 0%, the opening 60 is completely released. For this reason,
The oil pressure in the oil passage 46 becomes 0, and the spool 34 is completely switched to the left side in the drawing. In this state, hydraulic pressure is supplied from the oil passage 24 to the apply chamber 20, and the lock-up clutch
Since 18 is completely fastened, almost no oil flows out to oil passage 26.

Next, control of the lock-up clutch 18 according to the present invention will be described. Lock-up clutch 18 as described above
Is controlled in combination with the shift of the automatic transmission.

That is, the region where the lock-up clutch 18 is engaged is set according to the shift speed and the throttle opening. For example, the lock-up clutch 18 is completely engaged in the high throttle opening region of the third speed and the fourth speed. In this case, in the case of the 2-3 shift, the lock-up clutch 18 is engaged simultaneously with the shift. On the other hand, 3-4 shift and 4
In the case of the third shift, a shift from the gear in the locked-up engagement state to another gear in the locked-up engagement state is performed. During such a shift, half-clutch control of the lock-up clutch 18 is performed according to a control flow as shown in FIG. That is, first, it is determined whether or not a shift start has been commanded, and if so, it is determined whether or not the commanded shift is an upshift,
In the case of an upshift, _Su is set as the value of the target speed difference S, and in the case of a downshift, _Sd is set. The speed difference is a difference between the rotation speed of the pump impeller 12 and the rotation speed of the turbine runner 14. The value of S _u is set smaller than the value of S _d . Then, the actual engine speed N _e from each engine rotational speed sensor 66 and turbine speed sensor 68 (which is equal to the rotational speed of the pump impeller 12) and data of revolving speed N _t of the turbine runner 14. Then, performing the calculation of the actual speed difference R = N _e -N _t. The actual speed difference R obtained in this way is compared with the target speed difference S, and when R is larger than S, a signal for operating the solenoid 58 so as to reduce the oil pressure in the release chamber _Tr is output. , R is smaller than S, a signal for operating the solenoid 58 to increase the oil pressure in the release chamber _Tr is output.

As a result, the speed difference of the lock-up clutch 18 is controlled to a preset value during gear shifting by the above control, and the lock-up clutch 18 is brought into a half-clutch state. This allows the lock-up clutch during shifting
The increase in the engine rotation speed due to the change in the operation state of 18 is suppressed, the shock is reduced, and the fuel consumption of the engine is reduced. Note that the speed difference is reduced during upshifting (ie, the slip amount is reduced), and the speed difference is increased during downshifting (ie, the slip amount is increased).
This is done for the following reasons. In other words, in the case of an upshift, since the engine rotation speed is reduced after the shift is completed as compared to before the shift, the engine rotation speed is prevented from increasing during the shift as much as possible to reduce the shock.
On the other hand, the downshift is a shift in which the engine speed increases after the shift is completed as compared to before the shift, so that the slip amount is increased so that the engine speed increases faster, and the response is improved.

(G) Effects of the Invention As described above, according to the present invention, the set value of the target difference between the engine rotation speed and the turbine rotation speed at the time of gear shifting is smaller in an upshift than in a downshift. By setting this value, an increase in the engine speed is suppressed during an upshift, and shift shocks can be reduced.At the same time, an engine speed can be increased quickly during a downshift, improving responsiveness. it can.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between components of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, and FIG. 3 is a diagram showing a control flow. 18: Lock-up clutch, 58: Lock-up solenoid, 66: Engine speed sensor, 68: Turbine speed sensor.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 61/14

Claims (1)

(57) [Claims] An operating state of a lock-up clutch capable of connecting a pump impeller side and a turbine runner side of a fluid transmission device is controlled by a solenoid, and a lock-up operating region in which the lock-up clutch is in a completely engaged state is two or more. When the gear is set to the shift speed, and when shifting from the lock-up operation region of the predetermined gear to the lock-up operation region of another gear, the lock-up clutch is temporarily shifted to the half-clutch state during the shift. The clutch has a clutch means, and the half-clutch means during shifting is configured so that a difference between the engine rotation speed detected by the engine rotation speed sensor and the turbine rotation speed detected by the turbine rotation speed sensor is set to a preset value. Lock-up clutch configured to control the operation of the solenoid so that The control device switch, the setting value, the upshift is set smaller than the downshift, lockup clutch control apparatus which is characterized in that.