JP2774806B2 - Shift control device for automatic transmission with lock-up clutch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a case where a shift operation is performed under predetermined conditions in an automatic transmission equipped with a torque converter having a lock-up clutch mounted on a vehicle. The present invention relates to a shift control device for an automatic transmission with a lock-up clutch, which controls a slip state of a lock-up clutch of a torque converter.

(Prior Art) In a vehicle equipped with an automatic transmission equipped with a torque converter provided with a lock-up clutch in addition to a pump impeller constituting an input element and a turbine runner constituting an output element, a vehicle having a predetermined running state is not required. Thus, energy loss in the torque converter when torque is transmitted from the engine to the wheel drive system via the automatic transmission is reduced, and torque fluctuations of the engine are transmitted to the wheel drive system via the automatic transmission to occur. In order to achieve both reduction of vehicle body vibration and slip control, the lock-up clutch in the torque converter performs a fastening state in which a rotational speed difference occurs between the pump impeller and the turbine runner, that is, a slip fastening state. What has been proposed. The slip control of the lock-up clutch in the torque converter is, for example, a shift-up operation in an automatic transmission mounted on the vehicle while the vehicle is running at a vehicle speed within a predetermined speed range. This is also performed when a speed change operation is performed.

As described above, slip control (hereinafter referred to as shift-time slip control) of the lock-up clutch, which is performed when the shift operation in a predetermined mode is performed in the automatic transmission with the lock-up clutch mounted on the vehicle, is performed when the shift is performed. The main purpose is to reduce the shock generated at the time and improve the shift feeling received by the driver of the vehicle, for example, in Japanese Patent Application No. 62-249336 previously filed by the present applicant. As described, under the slip control condition relating to the lock-up clutch, the shift operation state of the automatic transmission is detected from the detection result of the shift speed and the change in the engine speed or the turbine speed. For example, if it is determined that the shift operation is being performed, the slip engagement state of the lock-up clutch is controlled. For a lock-up control solenoid valve that controls the hydraulic pressure difference acting on the lock-up clutch, the duty of the drive pulse signal that determines the valve opening period is set so as to be constant. It has been proposed that the shift operation is performed until the shift operation is completed under the condition that the oil pressure difference acting on the up clutch is fixed. In this way, by performing the slip control during shifting, a shock based on the torque difference between the engine side and the wheel side during shifting, and
It is expected that the shock resulting from the torque increasing effect of the torque converter is alleviated.

(Problems to be Solved by the Invention) However, as described above, when the slip control during shifting is performed under the condition that the duty of the drive pulse signal for the lock-up control solenoid valve is fixed, for example, When the vehicle is in an accelerated running state and the automatic transmission performs a shift operation that is a shift-up operation from the second speed to the third speed according to a preset shift characteristic, the engine speed and the speed of the turbine runner of the torque converter are performed. That is, the turbine speed changes as indicated by the curves NE and NT in the graph shown in FIG. 7, respectively, and when the engine speed is increased immediately after the shift operation is completed, A situation in which a desired torque fluctuation occurs may be imitated, and the driver of the vehicle may feel an unpleasant shock. .

FIG. 7 is a graph in which the rotation speed N is plotted on the vertical axis and the time t is plotted on the horizontal axis, and the shift is performed under the condition that the duty of the drive pulse signal for the lock-up control solenoid valve is constant. FIG. 7 shows a change in engine speed (NE) and a change in turbine speed (NT) when a shift operation with time slip control is performed. In such a situation, the shift operation starts at time t _s . is terminated at time t _e, in the later stage of the shift operation period from time t _o to the time t _e, and the engine speed and the turbine speed is substantially matched, substantially slip occurs in the lock-up clutch Is not in a state. As a result, when the engine speed is increased immediately after the shift operation ends at the time point t _e , an undesired fluctuation of the turbine speed as indicated by X, that is, an undesired torque fluctuation occurs. become.

It should be noted that assuming that the duty of the drive pulse signal for the lock-up control solenoid valve is constant and that the lock-up clutch does not substantially slip in the latter half of the shift operation period, torque may be caused by torque A change in the surface friction coefficient of the lock-up clutch, a change in the viscosity coefficient of the hydraulic oil, and the like due to a change in the oil temperature in the converter may be considered.

In view of such a point, the present invention provides a shift slip control for an automatic transmission including a torque converter having a lock-up clutch mounted on a vehicle, in response to an undesired torque fluctuation after a shift operation in the automatic transmission is completed. It is an object of the present invention to provide a shift control device for an automatic transmission with a lock-up clutch, which can be performed without causing a situation in which is caused.

(Means for Solving the Problems) In order to achieve the above object, a shift control device for an automatic transmission with a lock-up clutch according to the present invention is connected to an engine as shown in FIG. A shift operation in an automatic transmission including a torque converter having an input element, an output element, and a lock-up clutch capable of engaging a slip engagement state in which the input element and the output element are engaged in a relatively rotatable state is detected. A shift detecting unit, and a hydraulic supply unit that performs an operation of supplying an operating oil pressure for causing the lock-up clutch to take a slip engagement state based on a shift operation in a predetermined mode in the automatic transmission detected by the shift detecting unit. A rotational speed detecting means for detecting a rotational speed of each of an input element and an output element in a torque converter; Control means, wherein the hydraulic pressure control means detects the shift operation in a predetermined mode in the automatic transmission by the shift detection means and causes the lock-up clutch to assume a slip engagement state. The operating oil pressure supplied from the oil pressure supply means to the lock-up clutch for a period from the end of the shift operation after it is detected that the rotation speed of the output element is substantially the same as the rotation speed of the output element is reduced. , And controls the lock-up clutch to perform an operation of increasing the rotational speed difference between the input element and the output element.

(Operation) In the shift control apparatus for an automatic transmission with a lock-up clutch according to the present invention configured as described above, the shift control for shifting of an automatic transmission including a torque converter having a lock-up clutch is performed. In performing this, after the speed change operation in a predetermined mode in the automatic transmission is started, the rotation speed of the input element and the rotation speed of the output element in the torque converter become substantially the same, and the time after the end of the speed change operation In the latter period of the shift operation period of the automatic transmission up to the time point, or in addition to the period including the period immediately after the end of the shift operation, the hydraulic pressure supplied from the hydraulic supply unit to the lock-up clutch is controlled by the hydraulic control unit. Operation of increasing the rotational speed difference between the input element and the output element in the torque converter in the lock-up clutch, That is, an operation of increasing the slip ratio in the lock-up clutch is performed. As a result, at the time of the end of the shift operation in the predetermined mode in the automatic transmission, it is possible to avoid a state where the slip in the lock-up clutch does not substantially occur, and as a result, undesired after the end of the shift operation This prevents a situation in which the driver of the vehicle feels an unpleasant shock due to induction of a large torque fluctuation, and further improves the acceleration traveling performance of the vehicle after the end of the gear shifting operation.

(Embodiment) FIG. 2 shows an example of a shift control device for an automatic transmission with a lock-up clutch according to the present invention, together with a power plant of a vehicle to which the shift control device is applied.

The power plant of the vehicle shown in FIG.
The engine 10 includes, for example, an automatic transmission 20 and an automatic transmission 20.
It has four cylinders, and each of the four cylinders has an intake passage and an intake passage from an intake passage 14 in which a throttle valve 12 is disposed.
An air-fuel mixture formed with the fuel injected from the fuel injection valve arranged at 14 is supplied. Then, the torque from the engine 10 obtained by combustion of the air-fuel mixture in each cylinder is:
The power is transmitted to the wheel drive system via a power transmission path including the automatic transmission 20.

The automatic transmission 20 includes a torque converter 22, a multi-stage gear type transmission mechanism 24, and a lock-up control solenoid valve 26 that forms and supplies a working oil pressure used for controlling the transmission.
And a hydraulic circuit section 28 including the above.

The torque converter 22 is shown in FIG.
As shown in detail with a portion related to the operation control of the torque converter 22 in 28, a drive plate 30 that is rotationally driven by an output portion 10a in the engine 10
And a pump impeller 32 connected to the drive plate 30 and rotating therewith, a turbine runner 34 in which torque from the engine 10 is transmitted through the pump impeller 32, and between the pump impeller 32 and the turbine runner 34. A stator 36, and a one-way clutch 38 disposed between the stator 36 and a fixed portion of the torque converter 22.The turbine hub 40 is disposed between the drive plate 30 and the turbine runner 34. Torsion damper 42 spline-fitted to
A lock-up clutch 44 is connected to the torsion damper 42 via a coil spring 42a. The lock-up clutch 44 is entirely arranged to be close to and away from the drive plate 30, and is adapted to rotate together with the turbine runner 34.

A lock-up clutch 44 is provided between the drive plate 30 and the turbine runner 34 in the torque converter 22.
The back pressure chamber 48 and the internal pressure chamber 50
Is formed, and the back pressure chamber 48 is supplied with a hydraulic pressure that presses the lock-up clutch 44 away from the drive plate 30 through the oil passage 51 from the hydraulic circuit unit 28,
In addition, hydraulic pressure that presses the lock-up clutch 44 in a direction to approach the drive plate 30 is supplied to the internal pressure chamber 50 from the hydraulic circuit unit 28 through the oil passage 52. When the value of the oil pressure in the internal pressure chamber 50 is higher than the value of the oil pressure in the back pressure chamber 48 by a predetermined value or more, the lockup clutch 44
In the drawing, the pump impeller 32 is pressed to the right, thereby being frictionally engaged with the drive plate 30 to take a fastening state in which the pump impeller 32 and the turbine runner 34 are engaged with each other. When the value of the oil pressure in the back pressure chamber 48 is lower than the value of the oil pressure in the back pressure chamber 48 by a predetermined value or more, it is pushed to the left in FIG.
Is released from the frictional engagement with the pump impeller.
It is assumed that a release state is set in which the 32 and the turbine runner 34 are disengaged. In addition, lock-up clutch 44
When the pressure difference between the oil pressure in the back pressure chamber 48 and the oil pressure in the internal pressure chamber 50 is within a predetermined range, the pump impeller 32 and the turbine runner 34 are engaged in a relatively rotatable state. The slip engagement state with the drive plate 30 is taken, and the slip ratio with respect to the drive plate 30 decreases as the pressure difference increases. The internal pressure chamber 50 is connected to an oil cooler 55 through an oil passage 54 provided with a check valve 53.

A lock-up shift valve 56 and a lock-up control solenoid valve 26 for performing a slip control for controlling a slip engagement state of the lock-up clutch 44 are provided at portions of the hydraulic circuit unit 28 related to the operation control of the torque converter 22. Is provided. The lock-up shift valve 56 includes a spool 57 provided with lands 57a, 57b and 57c, and a spring 58 for urging the spool 57 rightward in FIG.
And ports a, b, c, d, e, f, g opened and closed by the spool 57.
And h. And ports a and f are oil passages
51 is connected to the back pressure chamber 48, port b is connected to an oil cooler 55 via an oil passage 64, and port c is connected to the internal pressure chamber 50 via an oil passage 52. An oil pump 64 is connected to an oil passage 64 through a branch oil passage 65, and ports d and e are connected through an oil passage 63 and further through a pressure regulating valve 61.
A port g is connected to an oil pump 62 through an oil passage 60 provided with a lock-up control solenoid valve 26, and a port h is connected to an oil pan T.

The speed change mechanism 24 is provided with various types of frictional engagement elements such as a planetary gear portion and a clutch or a brake for obtaining four forward steps and one reverse step. The release hydraulic pressure is
It is selectively supplied as appropriate via various control valves or shift valves provided therein. As a result, each frictional engagement element is set to the engaged state or the released state, and D that constitutes a P range (parking range), an R range (reverse range), an N range (neutral range), and a forward range. A range (drive range), an S range, and an L range, and first to fourth speeds in the forward range can be obtained.

Further, in addition to the above configuration, as shown in FIG.
In order to control the operation of the hydraulic circuit unit 28, a control unit 100 that supplies a drive signal Cf is provided to a lock-up control solenoid valve 26 built in the hydraulic circuit unit 28. The control unit 100 has a throttle valve 12
A detection signal St obtained from a throttle opening sensor 71 for detecting the opening of the vehicle, a detection signal Sv obtained from a vehicle speed sensor 72 for detecting the vehicle speed, and a transmission mechanism provided in the hydraulic circuit unit 28
24, a detection signal Ss obtained from a shift position sensor 73 that is connected to a manual valve for controlling the shift lever and detects an operation position of a shift lever operated by a driver.
And an engine speed sensor 74 for detecting the engine speed.
, And a detection signal Sm obtained from a turbine speed sensor 75 that detects the speed of the turbine runner 34. In addition, the control unit
Other detection signals Sx are also supplied to 100, and another drive signal Cx used for controlling the automatic transmission 20 is transmitted from the control unit 100.

The control unit 100 controls the speed change of the transmission mechanism 24 in the automatic transmission 20 and the operation control of the lock-up clutch 44 provided in the torque converter 22 based on the various detection signals described above.

When the shift control of the transmission mechanism 24 and the operation control of the lock-up clutch 44 are performed by the control unit 100, for example, in the case of the D range running state, the data is mapped and stored in the internal memory of the control unit 100. As shown in FIG.
The shift line L in the shift pattern diagram represented by the throttle opening Th on the vertical axis and the vehicle speed V on the horizontal axis
The opening degree of the throttle valve 12 represented by the detection signal St and the vehicle speed represented by the detection signal Sv are collated with a, Lb, Lc, Ld, Le, and Lf to determine whether a shift-up condition or a shift-down condition is satisfied. Further, the opening degree of the throttle valve 12 represented by the detection signal St on the lock-up operation line Lg and the vehicle speed represented by the detection signal Sv are collated to determine whether or not the lock-up operation condition is satisfied. The opening of the throttle valve 12 represented by the detection signal St on the control execution line Ls and the vehicle speed represented by the detection signal Sv are collated to determine whether the slip control condition for the lock-up clutch 44 is satisfied.

Shift lines La, Lb, and Lc in FIG. 4 relate to upshifting from first gear to second gear, second gear to third gear, and third gear to fourth gear, respectively. Lf relates to downshifting from 2nd gear to 1st gear, 3rd gear to 2nd gear, and 4th gear to 3rd gear, respectively. The lock-up operation line Lg indicates that the lock-up clutch 44 An operation region in which an engagement state for bringing the turbine runner 34 into engagement with the turbine runner 34 is to be taken. Further, the slip control execution line Ls is determined by the value Va of the vehicle speed V to the value Vb of the vehicle speed V and the value Ta of the throttle opening Th. , The operation range in which the slip control of the lock-up clutch 44 is to be performed.

When it is detected that the upshift condition or the downshift condition is satisfied, the control unit 100 selectively sends out the drive signal Cx so as to cause the transmission mechanism 24 to switch the gear position. Thus, the speed change control for the speed change mechanism 24 is performed.

Further, the control unit 100 controls the operation of the lock-up clutch 44, when it is detected that the lock-up operation condition and the slit control condition including the later-described shift control condition during shifting are not satisfied, Solenoid valve for lock-up control of drive signal Cf
No supply to 26. Therefore, when neither the lock-up operation condition nor the slit control condition is satisfied, the lock-up control solenoid valve 26 is maintained in the closed state, and the hydraulic oil from the oil pump 62 causes a decrease in hydraulic pressure. Lock-up shift valve through oil line 60 without
The oil pressure is supplied from the pressure regulating valve 61 to the port g in the port 56 and to each of the ports d and e in the lock-up shift valve 56. As a result, in the lock-up shift valve 56, the spool 57 assumes the position shown in FIG. 3, and the ports b, e, and h are closed by the land portions 57a, 57b, and 57c of the spool 57. Further, the port c and the port d are communicated with each other, and the operating oil obtained from the pressure regulating valve 61 at the port c is supplied to the internal pressure chamber 50 of the torque converter 22 through the oil passage 52. At this time,
Since the port f of the torque converter 22 connected to the back pressure chamber 48 through the oil passage 51 is shut off from the port h, the hydraulic oil in the back pressure chamber 48 is not discharged, and the hydraulic oil in the internal pressure chamber 50 is not discharged. When the oil pressure becomes equal to or higher than a predetermined pressure, the hydraulic oil in the internal pressure chamber 50 flows through an oil passage 54 provided with a check valve 53 to an oil cooler.
Discharged to 55.

Therefore, in such a case, in the torque converter 22, the lock-up clutch 44 is separated from the drive plate 30 and is in the released state, and the torque converter 22 assumes a converter state in which power transmission is performed via fluid. It is said.

On the other hand, when it is detected that the lockup operation condition is satisfied, the control unit 100 supplies the drive signal Cf to the lockup control solenoid valve 26,
Thus, the lock-up control solenoid valve 26 is opened.

When the lock-up control solenoid valve 26 is opened, the oil pressure of the hydraulic oil supplied from the oil pump 62 to the port g of the lock-up shift valve 56 is reduced, while the port d of the lock-up shift valve 56 is decreased. And e are supplied with hydraulic pressure from the pressure regulating valve 61. As a result, the spool 57 in the lock-up shift valve 56
3 is moved rightward in FIG. 3 according to the biasing force of the spring 58, so that the port c and the port d of the lock-up shift valve 56 are communicated, and the port f and the port h are communicated. Is supplied to the internal pressure chamber 50 of the torque converter 22 through the oil passage 52, and the hydraulic oil in the back pressure chamber 48 passes through the oil passage 51. Exit port 56 from port f to port h.
From the oil pan T.

Therefore, when the drive signal Cf is supplied to the lock-up control solenoid valve 26, the torque converter 22
In this case, the hydraulic pressure in the back pressure chamber 48 becomes lower than the hydraulic pressure in the internal pressure chamber 50, and the differential pressure causes the lock-up clutch 44 to be pressed toward the drive plate 30 to be frictionally engaged with the drive plate 30. In the engaged state, the torque converter 22 assumes a lock-up state in which the pump impeller 32 and the turbine runner 34 are engaged.

Further, when it is detected that the slip control condition is satisfied, the control unit 100 supplies the drive signal Cf to the lock-up control solenoid valve 26,
The lock-up control solenoid valve 26 is intermittently opened, and the drive signal Cf is changed according to the slit control condition, so that the lock-up control solenoid valve 26 that is intermittently opened is opened. Control is performed to change the period during which the state is maintained.

As a result, the degree of decrease in the hydraulic pressure of the hydraulic oil supplied from the oil pump 62 to the port g of the lock-up shift valve 56 changes, and after the hydraulic oil in the back pressure chamber 48 passes through the oil passage 51, the lock-up shift Move valve 56 from port f to port h
And the discharge amount upon discharging from the port h to the oil pan T changes, and accordingly, the differential pressure between the hydraulic pressure in the internal pressure chamber 50 of the torque converter 22 and the hydraulic pressure in the back pressure chamber 48 increases. As a result, the frictional engagement force of the lock-up clutch 44 with the drive plate 30 changes. As a result, the lock-up clutch 44
The pump impeller 32 and the turbine runner 34 are engaged in a relatively rotatable state, and the slip ratio at that time is changed according to the drive signal Cf. Thus, the slip control of the lock-up clutch 44 is performed.

Among the slip control conditions, in particular, the above-described shift slip control condition is, for example, a condition in which the throttle opening degree represented by the detection signal St and the vehicle speed represented by the detection signal Sv are shown in FIG. The shift-up condition is satisfied based on the fact that the vehicle is in the area surrounded by the slip control execution line Ls in the shift pattern diagram and the vehicle speed represented by the detection signal Sv and the throttle opening indicated by the detection signal Sv. This is achieved by performing a shift operation that is a shift-up operation in the transmission mechanism 24 of the machine 20. Accordingly, in the D range running state, the control unit 100 determines that the throttle opening indicated by the detection signal St is equal to or less than Ta and , The vehicle speed represented by the detection signal Sv
When the vehicle is in the vehicle speed range from Va to Vb, and the upshift according to the shift line La, Lb or Lc is to be performed, the slip control of the lockup clutch 44 as described above is performed. Thus, the slip control during shifting is performed.

When the shift control during shift is performed, the control unit 100 controls the drive signal Cf supplied to the lock-up control solenoid valve 26 when the shift operation of shifting up is not performed in the transmission mechanism 24. About the solenoid valve for lock-up control
The drive signal Cf is calculated by adding a correction duty value ΔDpa obtained based on a correction value map previously stored in the built-in memory to the reference duty value Dp to determine the duty DF for determining the period during which the 26 is in the open state. Is sent to the lock-up control solenoid valve 26 as a signal having a pulse width corresponding to the calculated duty DF = Dp + ΔDpa.

Then, when it is detected in the transmission mechanism 24 that a shift operation for shifting up from second gear to third gear is performed, the control unit 100 controls the engine speed Ne during the shift operation. It is detected whether or not the rotational speed difference ΔN (ΔN = Ne−Nt) between the engine speed and the turbine rotational speed Nt is zero. If the rotational speed difference ΔN is not zero, the drive signal Cf Is set as Dp + ΔDpa as described above, and the drive signal Cf
To the lock-up control solenoid valve 26 as a signal having a pulse width corresponding to the duty DF = Dp + ΔDpa.

Thereafter, during the shifting operation, when the rotation speed difference ΔN becomes zero, that is, when the engine rotation speed Ne and the turbine rotation speed Nt
Is equal to, the duty DF of the drive signal Cf is set to a constant value Da smaller than Dp + ΔDpa without using a correction value map, and the hydraulic pressure and the back pressure in the internal pressure chamber 50 of the torque converter 22 are set. The drive signal Cf is sent to the lock-up control solenoid valve 26 as a signal having a pulse width corresponding to the duty DF = Da in order to reduce the pressure difference between the oil pressure in the chamber 48 and maintain the pressure difference constant.

In this manner, when the pressure difference between the oil pressure in the internal pressure chamber 50 and the oil pressure in the back pressure chamber 48 of the torque converter 22 is such that the drive signal Cf is a signal having a pulse width corresponding to the duty DF = Dp + ΔDpa As a result, the slip ratio of lock-up clutch 44 is increased.

Further, after that, after the elapse of a period set from the start of the shift operation to the shift operation period or more, that is, after the set time after the end of the shift operation,
The duty DF for the drive signal Cf is calculated again by adding the correction duty value ΔDpa obtained based on the correction value map to the reference duty value Dp,
The drive signal Cf is sent to the lock-up control solenoid valve 26 as a signal having a pulse width corresponding to the calculated duty DF = Dp + ΔDpa.

In this way, under the gear shift slip control operation, the engine speed Ne and the turbine speed Nt are:
In the graph shown in FIG. 5, the curves NE 'and N
It changes as represented by T '. FIG. 5 shows that the rotational speed N is plotted on the vertical axis and the time t is plotted on the horizontal axis. In this case, the fluctuation operation starts at time t _s ′ and at time t _e ′ The gear shifting operation has been completed
It has been. The engine rotation speed Ne and the turbine rotation speed Nt have a predetermined rotation speed difference ΔN at the time point t _s ′ at which the shift operation is started, but the shift operation period
At time t _o ′ during Tu, after the time t _o ′, after the end of the shifting operation period Tu up to the time t _e ′, and after the end of the shifting operation after the time t _e ′, the predetermined time is again set. Of rotation speed differences ΔN. At this time, during the gear shift operation period Tu, the drive signal is kept until the time point t _o ′ at which the engine speed Ne and the turbine speed Nt match.
Cf is converted into a signal having a pulse width corresponding to the duty DF = Dp + ΔDpa, and is sent to the lock-up control solenoid valve 26. From the time t _o ′, the gear shift operation is performed beyond the time t _e at which the gear shift operation ends. In a period Tw measured from the start time t _s ′ to a time t _x where a period To longer than the shift operation period Tu passes, the drive signal Cf has a duty DF = Da.
Is a signal having a pulse width corresponding to, it is transmitted to the lock-up control solenoid valve 26, further, at the time t _x after, again, the drive signal Cf duty DF = Dp + delta
A signal having a pulse width corresponding to Dpa is sent to the lock-up control solenoid valve 26.

In this manner, the time point t _o ′ during the speed change operation period Tu.
From the end of the gear shift operation period Tu to the time point t _e ′ and the time point
In the period after the end of the shifting operation from t _e ′ to time t _x ,
The drive signal Cf is a signal having a pulse width corresponding to the duty DF = Da and sent to the lock-up control solenoid valve 26. As a result, the hydraulic pressure in the internal pressure chamber 50 of the torque converter 22 and the hydraulic pressure in the back pressure chamber 48 And the slip ratio in the lock-up clutch 44 is increased, so that the engine speed Ne and the turbine speed Nt have a predetermined speed difference ΔN during such a period. As a result, at the end of the shift operation, it is possible to avoid a state where substantially no slippage occurs in the lock-up clutch 44. This prevents the driver from feeling unpleasant shock, and further improves the acceleration traveling performance of the vehicle after the shift operation is completed. Is will be.

Control unit 10 that performs the control operation as described above
0 is configured using, for example, a microcomputer. An example of a program executed by the microcomputer in such a case for performing the slip control during shifting will be described with reference to the flowchart in FIG.

In the program shown in the flowchart of FIG. 6, after the start, various detection signals S
t, Sv, Ss, Sn, Sm, Sx, etc.
At 102, it is determined whether a slip control condition is satisfied. The determination on such a slip control condition is, for example, under the condition that the vehicle is in the D range running state.
The determination is made by determining whether the throttle opening represented by the detection signal St and the vehicle speed represented by the detection signal Sv are within the range surrounded by the slip control execution line Ls in the shift pattern diagram shown in FIG. Will be As a result, when it is determined that the slip control condition is satisfied, in the process 103, the turbine speed Nt calculated based on the detection signal Sm is calculated from the engine speed Ne calculated based on the detection signal Sn. Then, the rotation speed difference ΔN is calculated.

Subsequently, in decision 104, it is determined whether or not the upshift is performed in the transmission mechanism 24 of the automatic transmission 20. Such an upshift is determined by comparing the throttle opening represented by the detection signal St and the vehicle speed represented by the detection signal Sv with the transmissions La, Lb and Lc in the shift pattern diagram shown in FIG. Will be If it is determined that the state is not a state in which the upshift is performed, the process 105
03 is compared with the correction value map to determine the corresponding correction duty value ΔDpa. Subsequently, in process 106, the correction duty value ΔDpa is added to the reference duty value Dp, and the duty DF = Dp + ΔDpa
And proceeds to process 107. In the process 107, the duty DF calculated in the process 106 = Dp + ΔDpa
Is generated and supplied to the lock-up control solenoid valve 26, and the process returns to the process 101.

If it is determined in the decision 104 that upshifting is to be performed, the process 108 is started.
After the built-in timer is started, it is determined in decision 109 whether or not the rotational speed difference ΔN calculated in the process 103 has become zero, and it is determined that the rotational speed difference ΔN has not become zero. Process 105
And the operation in each of the subsequent steps is performed as described above.

When it is determined in the decision 109 that the rotation speed difference ΔN has become zero, the duty DF is set to a value Da smaller than Dp + ΔDpa calculated in the process 106 in the process 110, and in the next process 111, the process A drive signal Cf having a pulse width corresponding to the duty DF = Da set at 110 is formed and supplied to the lock-up control solenoid valve 26.

Next, in decision 112, it is determined whether or not the measurement time J of the built-in timer is equal to or longer than the time Jo corresponding to the elapse of the period To set to be equal to or longer than the shift operation period Tu, and the timer measurement is performed. If the time J is shorter than the time Jo, the process returns to the process 110, and the operation in the process 110 and the process 111 and the determination in the decision 112 are repeated. When it is determined in the decision 112 that the measured time J of the timer is equal to or longer than the time Jo, in the process 113, the timer is stopped, and then the process proceeds to the process 105, and the operation in each step thereafter is performed as described above. To do.

On the other hand, if it is determined in the decision 102 that the slip control condition is not satisfied, the process proceeds to a process 114, and in the process 114, a control program for control other than the slip control of the lock-up clutch 44 for the torque converter 22 is executed. Execute and return to process 101.

In the above-described example, it is determined whether the rotation speed difference ΔN has become zero in the decision 109. However, instead of such a determination, in the decision 109,
A determination may be made as to whether the rotational speed difference ΔN has become a relatively small value.

(Effects of the Invention) As is clear from the above description, according to the shift control device for an automatic transmission with a lock-up clutch according to the present invention,
In performing the shift slip control for the automatic transmission including the torque converter having the lock-up clutch, the latter half of the shift operation period in which the shift operation in a predetermined mode is performed in the automatic transmission related to the shift slip control. Alternatively, during a period in which a period after the end of the shift operation is added thereto, the slip ratio of the lock-up clutch is increased, so that at the end of the shift operation in a predetermined manner, the lock-up clutch is substantially locked up. This prevents the clutch from slipping. Therefore, it is possible to prevent a situation in which undesired torque fluctuation is induced after the shift operation in the predetermined mode in the automatic transmission related to the shift control during shifting, and the driver of the vehicle feels uncomfortable shock. And
Further, the acceleration traveling performance of the vehicle after the end of the fluctuation operation is improved.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram showing a shift control device of an automatic transmission with a lock-up clutch according to the present invention in accordance with the claims, and FIG. 2 is a shift control of the automatic transmission with a lock-up clutch according to the present invention. FIG. 3 is a schematic configuration diagram showing an example of a control device together with a power plant of a vehicle to which the control device is applied, FIG. 3 is a schematic configuration diagram showing a main part of the example shown in FIG.
FIG. 5 and FIG. 5 are characteristic diagrams for explaining the operation of the example shown in FIG. 2, and FIG. 6 is a diagram showing the case where a microcomputer is used for the control unit in the example shown in FIG. FIG. 7 is a flow chart showing an example of a control program executed by a computer. FIG. 7 is a characteristic diagram used for explaining a shift slip control in an automatic transmission having a conventionally proposed torque converter having a lock-up clutch. In the figure, 10 is an engine, 20 is an automatic transmission, 22 is a torque converter, 24 is a transmission mechanism, 26 is a solenoid valve for lock-up control, 28 is a hydraulic circuit, 30 is a drive plate, 32 is a pump impeller, and 34 is Turbine runner, 44 is a lock-up clutch, 48 is a back pressure chamber, 50 is an internal pressure chamber, 56 is a lock-up shift valve, 71 is a throttle opening sensor, 72 is a vehicle speed sensor, 73 is a shift position sensor, and 74 is an engine speed. A sensor, 75 is a turbine speed sensor, and 100 is a control unit.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 61/14

Claims (1)

(57) [Claims] 1. A torque converter having an input element and an output element connected to an engine, and a lock-up clutch capable of establishing a slip engagement state in which the input element and the output element are engaged in a relatively rotatable state. Shift detecting means for detecting a shift operation in the automatic transmission; and causing the lock-up clutch to assume the slip engagement state based on the shift detecting means detecting a shift operation in a predetermined mode in the automatic transmission. Hydraulic pressure supply means for supplying an operating hydraulic pressure for the motor, rotational speed detecting means for detecting respective rotational speeds of the input element and the output element in the torque converter, and the shift detecting means detecting the shift operation. And the lock-up clutch assumes the slip-engaged state. From the hydraulic pressure supply means to the lock-up clutch for a period from the end of the shift operation to the point in time after it is detected that the rotational speed of the input element and the rotational speed of the output element have become substantially the same. Hydraulic pressure control means for controlling the hydraulic pressure supplied to the lock-up clutch to perform an operation of increasing the rotational speed difference between the input element and the output element. Control device for automatic transmission with lock-up clutch.