JPH0684782B2 - Lockup controller for automatic transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic transmission that automatically shifts gears according to the operating state of an automobile or an engine, and more particularly to a lockup of an automatic transmission having a lockup function. Regarding the control device.

(Prior Art) Generally, in an automatic transmission, a plurality of gear stages are obtained by combining a torque converter and a speed change gear mechanism and switching a power transmission path of the speed change gear mechanism by selectively operating a plurality of friction members. However, a lock-up mechanism that directly connects the input side and output side of the torque converter when the vehicle speed reaches or exceeds a predetermined value is provided to reduce loss in the torque converter and improve power transmission efficiency. Things are known. This is because the engine output shaft and the speed change gear mechanism are connected by a lock-up clutch that directly connects the input side and the output side of the torque converter in a predetermined operating region that does not require the torque increasing action of the torque converter or the shock absorbing action during shifting. It is mechanically coupled, for example, a control circuit that determines the operating region and instructs the lockup clutch to be engaged or disengaged, and is turned on or off by a signal from this circuit. It is composed of a solenoid valve and a lockup valve for engaging and disengaging the clutch by supplying and discharging hydraulic pressure to and from the lockup clutch according to the operation of the valve.

However, in the automatic transmission having the lock-up function, if the gear shift is performed while the lock-up is in the ON state, the fluctuation and vibration of the acceleration of the vehicle at the time of gear shift increase, and a good ride comfort is obtained. Inhibit. Therefore, in order to effectively prevent such acceleration fluctuations and vibrations, there has been proposed a device in which the lockup is maintained in the OFF state during a shift (for example, Japanese Patent Laid-Open No. 57-76359).

However, in the ON / OFF region of the lockup, the relationship between the turbine speed and the throttle opening is usually set as shown in FIG. Assuming that the accelerator opening is constant and the vehicle speed is increasing as indicated by arrow A in FIG.
When shifting up from the 3rd gear to the 4th higher gear, the lockup is ON at the 3rd gear → OFF at the 4th gear lockup →
Transitions to 4-speed lockup ON. In other words, the lock-up ON / OFF causes a two-stage shock to the vehicle, which gives an occupant a discomfort.

In order to solve this, when the shift line from the 3rd speed to the 4th speed and the 4th speed lockup ON line are made to be the same line, for example, as shown by an arrow B in FIG. 3, the accelerator is gradually depressed. When going out, 4-speed lockup ON → 3
Fast lock-up is turned on, and the lock-up off state disappears when shifting down, which is not desirable. Also, a shift line from 3rd to 4th and lockup to 4th
The ON line may be separated from the ON line in the direction of the number of revolutions of the turbine, but in this case, the lockup ON zone (lockup zone) becomes narrower because the 4-speed lockup ON line moves to the high speed side. Cause

(Object of the Invention) The present invention solves the above problem in an automobile equipped with an automatic transmission with a lock-up function, and locks up because the rotational speed is large and the torque is small at the time of shift-up at a high-speed gear stage. In view of the small shock that may occur even when the gear is on, it is an object of the present invention to avoid the above-described shock of turning on the lockup again after the shift-up by not releasing the lockup.

(Structure of the Invention) A lockup control device for an automatic transmission according to the present invention includes a torque converter connected to an output shaft of an engine, a speed change gear mechanism disposed on an output side of the torque converter, and the speed change gear mechanism. And a plurality of friction members for obtaining a plurality of speed stages by switching the power transmission paths of the lock converter, and a lockup clutch for directly connecting the input side and the output side of the torque converter is provided, and the lockup clutch is turned on and off. In the automatic transmission having lock-up control means for controlling the lock-up control means, the lock-up control means sets a lock-up ON area at least at two high-speed adjacent gears and shifts up to a higher gear in the lock-up ON state. The lock-up on state continues when the lock-up is performed, and the lock-up is It is configured to release the pon state.

With this configuration, the shift-up at the adjacent gears at high speed is kept in the lock-up ON state, the shock due to the re-lock-up ON after the shift-up is eliminated, and the lock-up is performed because the shift-up is performed at high speed. Despite the gear shifting in the up-on state, the shock is small.

(Embodiment) FIGS. 1 (a) and 1 (b) show the construction of an embodiment of a lockup control device for an automatic transmission according to the present invention, in which an engine output shaft 1
To the torque converter 2, the speed change gear mechanisms 3, 4, 5 arranged on the output side of the torque converter 2, and a plurality of frictions for switching the power transmission paths of the speed change gear mechanisms 3, 4, 5. The torque converter has members 6, 7, 8, 9, 10, 11 and is configured to obtain a plurality of shift speeds by selectively operating the friction members 6 to 11. 2, a lock-up clutch 13 for directly connecting the engine output shaft 1 and the torque converter output shaft 12 is provided, and further, the friction members 6 to 11 are selected according to the operating state of the engine or the automobile and the shift operation of the transmission. As a means for controlling the operation and engagement / disengagement of the lock-up clutch 13, a control unit (ECU) 21 and an O
The hydraulic circuit 24 includes a plurality of shift solenoid valves 22 that are turned on and off, a lockup solenoid valve 23, and an actuator that is operated by these solenoid valves 22 and 23.

The control device 21 is composed of a microcomputer or the like, and has at least a shift control unit 21a and a shift solenoid drive unit 21a ', a lockup control unit 21b and a lockup solenoid drive unit 21b', and a throttle opening degree. The respective detection signals of the sensor 25, the turbine speed sensor 26, and the select lever sensor 27 are input, and the lockup control unit 21b and the lockup solenoid drive unit 21b 'in the control device 21 and the lockup unit are used. A lockup control means 28 for instructing and driving whether to engage or disengage the lockup clutch 13 according to an operating state such as an engine load and a vehicle speed is constituted by the solenoid valve 23 and the like. Further, as shown in FIG. 1 (b), the lock-up control section 21b comprises a lock-up judging means, a shift detecting means for a high speed upper gear, a lock-up continuing means and a releasing means thereof.

In the present invention, the lock-up control means 28 sets the lock-up ON region at two adjacent gears of at least high speed (for example, the third speed and the fourth speed) as shown in FIG.
When shifting up to a higher gear in the lock-up ON state, lock-up is ON even in areas other than the lock-up ON area
The state is continued, and when it is detected that the lockup ON region of the upper gear is entered, the control state according to the region setting is restored. Also, when shifting down from the 4th speed lockup ON state to a lower gear (3rd speed), the lockup is immediately released (OFF) when the 4th speed lockup OFF line is crossed. . It should be noted that due to changes in operating conditions in the 4th speed range, the 4th speed lockup OF
When crossing the 4th speed lockup ON line from the F state, the lockup is turned ON.

In FIG. 3, the horizontal axis represents the turbine speed and the vertical axis represents the throttle opening. The curve L ₁ is the line on the right side which is in the fourth-speed lockup ON region, and the curve L ₂ is the left side. The line in the 4th-speed lockup OFF region, the curve L ₃ indicates the line in the 3rd-speed lockup ON region on the right side, and the boundary line CA is the shift-up line from the 3rd speed to the 4th speed, and the boundary line C ₂ indicates a downshift line from 4th gear to 3rd gear. Then, such a shift pattern has the above-mentioned control device.
21 is stored as a map, and each sensor 2
Based on the input signal of 5,26,27, etc., the control device 21 controls the shift solenoid valve 22 and the lockup solenoid valve.
It is configured to output a control signal to 23 or the like.

Next, the structure of the torque converter in the automatic transmission will be described with reference to FIG. 2. The torque converter 2 is connected to the output shaft 1 of the engine through a drive plate 31 and a case 32, and the case 32 has one side. A pump 33 fixed to one side, a turbine 34 arranged opposite to the pump 33 on the other side of the case 32, and a turbine hub 35 integral with the turbine 34, one end of which is spline-fitted to form a transmission gear. A torque converter output shaft (turbine shaft) 12 protruding to the mechanism side, and a fixed shaft 36 interposed between the pump 33 and the turbine 34 and projecting into the case 32 and supported via a one-way clutch 37. And a stator 38 that has been mounted.

Then, the rotation of the engine output shaft 1 from the pump 33 to the case
The hydraulic oil filled in 32 is transmitted to the turbine 34, and the rotation of the turbine 34 is further transmitted to the transmission gear mechanism via the turbine shaft 12. Further, the stator 38 has a function of increasing the torque of the pump 33 and transmitting the torque to the turbine 34 when there is a difference in rotational speed between the pump 33 and the turbine 34.

The torque converter 2 has a lock-up clutch 13 incorporated therein. The lockup clutch 13 is disposed between the front wall portion 32a of the case 32 and the turbine 34, rotates integrally with the turbine hub 35, and is movably supported in the axial direction. And the front wall of the case 32
When the lockup releasing hydraulic pressure is supplied to the working chamber 39 provided between the lockup clutch 13 and the clutch 32a, the clutch 13 is separated from the front wall 32a of the case, and the torque converter 2 operates as described above. Although acting as a converter, when the hydraulic pressure in the working chamber 39 is discharged, the lockup clutch 13 is pressed against the case front wall portion 32a by the working oil in the case 32, and the case 32 and the turbine 34
Are coupled with each other, and the rotation of the engine output shaft 1 is directly transmitted to the turbine shaft 12 or the speed change gear mechanism to be in a lockup state.

As shown in FIG. 1, the automatic transmission has a transmission gear mechanism 3 to which rotation is input by the turbine shaft 12.
Hydraulic circuit 24 having a hydraulic actuator for activating friction members 6 to 11 such as a plurality of clutches and brakes for switching power transmission paths of solenoid valves 5, solenoid valves 22 for selectively supplying hydraulic pressure to each actuator, The hydraulic circuit 24 is provided with a hydraulic oil supply line 41 for supplying hydraulic oil into the torque converter 2 and a hydraulic circuit 24 in the torque converter 2 as shown in FIG. A hydraulic oil discharge line 43 for discharging the heated hydraulic oil and supplying it to each lubrication portion of the transmission through an oil cooler 42, and a lock-up in a working chamber 39 in the torque converter 2 branched from the supply line 41. A lock-up release line 44 for supplying release hydraulic pressure is provided, and a lock-up valve 45 is provided so as to cross the release line 44. A control oil line 47 is guided to one end of the lockup valve 45 through an orifice 46, and a drain line 48 is provided on the downstream side of the orifice 46 in the line 47, and a solenoid for opening and closing the drain line 48. A valve 23 is provided. The solenoid valve 23 closes the drain line 48 when it is ON (excitation) and applies a control pressure to one end of the lockup valve 45. Further, at this time, the lockup valve 45 is moved from the position where the release line 44 shown in the figure is communicated against the spring 45a attached to the other end side to the position where the downstream portion 44a is communicated with the drain port 45b, As a result, the release hydraulic pressure is discharged from the working chamber 39, and the lockup clutch 13 is engaged.

Next, the operation of the lockup control by the control device 21 having the above configuration, particularly the lockup control device 28, will be described.

The control device 21 receives signals from the throttle opening sensor 25, the turbine speed sensor 26, and the select lever sensor 27 to determine whether or not the operating state is in the lockup region from the map as shown in FIG. When it is in the up region, as described above, the lockup solenoid drive unit 21
b ′ drives the lockup solenoid valve 23, and the lockup clutch 13 is engaged via the hydraulic circuit 24,
The lockup is turned on. On the other hand, when the operating state is not in the lockup region, the lockup clutch 13 is released and the lockup OFF state is set.

Here, first of all, high speed gear, for example, for the lock-up control at the fourth speed will be explained with reference to the flowchart of FIG. 4, step S ₁ operating state lockup at the current OF
It is determined whether or not the F state, if this determination is NO, that is,
If the lockup ON state in step S ₂ determines whether or not it is immediately after upshift from third speed. If it is immediately after shifting from the 3rd-speed lockup ON state to the 4th-speed, the above determination is YES, the process proceeds to step S ₃ , and the FLAG
Set to "1" (Flag) 1, the procedure proceeds to step S _4.
In step S ₄ lockup is determined whether the forced OFF condition. The forced OFF condition is, for example, when the foot brake is ON or the throttle opening is fully closed. When in this forced OFF condition shifts from OFF the lock-up at step S ₅ to step _7, in the forced proceeds to step S ₆ when not in OFF condition, where the map shown in FIG. 3 4 It is determined whether the line is on the right side of line L _{1 for} fast lockup ON. If this determination is YES, that is, when the fourth-speed lockup ON region is entered, step S ₇
, Reset FLAG1 to "0" and return,
When the determination in step S ₆ is NO, that is, when the operating condition is not on the right side of the line L ₁ , the FLAG ₁ is not reset to “0” and the process returns. Thus, in any case, the lockup ON will be continued immediately after the upshift in the lockup ON state.

Next, when a predetermined time has passed from the shift up,
The judgment in S ₂ becomes NO, the process moves to step S ₈ , FLAG 1
Is "1", and if this judgment is YES,
When the determination is NO, that is, when the operating condition is on the right side of the line L _{1 and} FLAG 1 is reset to “0” in step S _{7, the} process proceeds to step S ₄ and the same flowchart is executed. , the process proceeds to step S _9, examined here whether the operating condition is in the left side of the line L ₂ on the map. When the determination is that the NO clogging operating condition is the line L ₂ on the right side is held as it is returned to the lock-up ON, when the judgment is shifted to the left from the YES clogging line L _2, the lock at step S ₅ Up is turned off.
In other words, after a predetermined time has passed from the shift up, once the driving state enters the lockup ON region of the fourth speed, the continuation of the lockup ON state at the time of shift up is released,
After that, the lockup will be changed depending on the driving condition at that time.
ON / OFF controlled.

If the current lockup is OFF in the determination in step S ₁ , the process proceeds to step S ₁₀ , in which it is checked whether the operating state is on the right side of the line L ₁ on the map, and this determination is If NO, return as is,
If YES, it is determined that the lockup ON area has been entered, and the lockup is turned ON in step S ₁₁ .

According to the above control, when the third-speed lockup ON state is shifted up to the fourth speed as shown by the arrow A in FIG. 3, the lockup is not released, and even if the lockup ON is continued in this way. The shift shock is extremely small because there is little change in torque due to the upshift in the 3rd → 4th high speed stage. In addition, even if the vehicle continues to drive with the lockup ON in the hatched area in Fig. 3, in this case the accelerator opening is almost constant and the driver does not strongly request acceleration. There is no problem.

Next, the 3rd-speed lockup control will be described with reference to the flowchart of FIG. 5. In step n ₁ , it is determined whether or not the current operating state is the lockup OFF state, and if this determination is YES, that is, the lockup is performed. If it is up OFF,
Step n ₂ at examining whether from 3 speed lockup ON line L ₃ in the map of FIG. 3 to the right, and directly returned if NO, the ON the lock-up at step n ₃ If YES And return.

If the determination in step n ₁ is NO, that is, if the lockup is ON, then in step n _{4 the} fourth speed lockup
Check whether it is downshift from ON. If this determination is NO, in step n _5, it is checked whether or not it is on the left side of the 3rd-speed lockup OFF line, and if NO, the routine returns and continues the lockup ON, and if YES, the step Move to n ₆ , turn off lockup, and then step n ₇
Determine whether or not shift change at, if during the gear shift process returns to step n _6, returns when no longer in speed.

By the above control, the lockup is always released during the downshift from the 4th speed to the 3rd speed, and proper acceleration can be smoothly performed by the downshift. Also, as shown by arrow B in FIG. 3, when the 4th speed lockup ON state is crossed over the 4th speed lockup OFF line, the lockup is immediately released and controlled according to the lockup map of FIG. It

In the above description, the shift-up from the third speed to the fourth speed and the shift-down from the fourth speed to the third speed have been described. Although the throttle opening and the turbine speed are used as the input signals to the control device 21 indicating the above, a signal corresponding to the engine load and a vehicle speed signal may be used instead.

(Effects of the Invention) As described above, according to the present invention, in a vehicle equipped with an automatic transmission having a lock-up function, the lock-up on-zone is set at at least two adjacent high-speed gear stages, and the lock-up on-zone is set. When shifting up to the upper stage in the up-on state, the lock-up on state is maintained, and the lock-up is turned off when shifting down. Therefore, there is little shift shock, and it is possible to avoid the two shocks that occur when the lock-up is turned off at the time of shift-up and then the lock-up is turned on again as in the conventional case, and therefore the occupant does not feel uncomfortable. It is possible to eliminate giving, and the driving feeling becomes good.

[Brief description of drawings]

1 (a) and 1 (b) are an overall configuration diagram and a configuration diagram of a main part of a lockup control device for an automatic transmission according to an embodiment of the present invention, and FIG. 2 is a configuration diagram of a torque converter portion in the device, FIG. 3 is a graph showing ON / OFF of lockup and shift shift regions for explaining the control of the device, and FIG. 4 is a flowchart of 4th speed lockup control,
FIG. 5 is a flowchart of the third speed lockup control. 1 ... Engine output shaft, 2 ... Torque converter, 3
〜5 …… Transmission gear mechanism, 6 ～ 11 …… Friction member, 12 …… Torque converter output shaft, 13 …… Lockup clutch,
21 ... Control device, 21b ... Lockup control unit, 21b '...
… Lockup solenoid drive, 23 …… Lockup solenoid valve, 24 …… Hydraulic circuit, 28 …… Lockup control means.

Claims (1)

[Claims] 1. A torque converter connected to an output shaft of an engine, a speed change gear mechanism disposed on the output shaft of the torque converter, and a power transmission path of the speed change gear mechanism are switched to obtain a plurality of shift stages. An automatic transmission having a plurality of friction members, and a lock-up clutch that directly connects the input side and the output side of the torque converter, and a lock-up control means for turning on and off the lock-up clutch, The lock-up control means sets the lock-up on region at least at two high-speed adjacent gears, and when the gear is shifted up to a higher gear in the lock-up-on state, the lock-up on-state is maintained and the lock-up is continued. Characterized by being configured to release the lock-up on state when shifting down to a lower gear in the on state The lock-up control device for an automatic transmission that.