JPH07174225A - Slip controller for lockup clutch for vehicle - Google Patents

Abstract

PURPOSE:To prevent upwash of an engine at the time of no load, prevent any shock in reengagement, and reduce its thermal load, by detecting whether it is shifted or not by a shift detection means and completely engaging a lockup clutch during shifting in the case of slip control before and after shifting. CONSTITUTION:Output of an engine 10 is transmitted from a torque converter 12 having a lockup clutch 32 connected to an input shaft 20 through a damper and an automatic transmission 14 to drive wheels via a differential gear, etc. When the oil pressure in an open-side oil chamber 36 becomes higher than that in an engagement-side oil chamber 34 in the torque converter 12, the lockup clutch 32 comes in its disengaged state so as to transmit torque at an amplification rate according to input/output rotation speed ratio of the torque converter 12. When the oil pressure in the engagement-side oil chamber 34 becomes higher, engine output is transmitted from a crankshaft 16 to the input shaft 29 via the lockup clutch 32. In the case of shifting from complete engagement to slip control and from slip control to complete engagement, a target rotation speed difference is changed gradually without any incongruity sense due to engine rotation speed changes so as to smoothly change a slip state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slip control device for a vehicle lock-up clutch, and more particularly to control during gear shifting.

[0002]

2. Description of the Related Art In an automatic vehicle having an automatic transmission, the engine output is transmitted to the automatic transmission via a hydraulic transmission such as a torque converter, but it is locked in parallel with the hydraulic transmission. The provision of an up-clutch and engaging or slip-engaging the lock-up clutch for the purpose of improving fuel efficiency and absorbing torque fluctuations is disclosed in, for example, Japanese Patent Laid-Open Nos. 62-297567 and 2-80857. Have been described. Further, when the automatic transmission has a plurality of shift speeds and the lock-up clutch is engaged and controlled at a plurality of continuous shift speeds, the shift shock is mitigated when engaging or slipping before and after shifting. In order to achieve this, it is usual to temporarily release the lockup clutch during gear shifting, but during steady running with a small throttle valve opening, the engine will blow up or lockup due to the release of the lockup clutch. Since it is easy to feel a shock due to a decrease in engine rotation speed when the clutch is re-engaged, maintaining the lock-up clutch in the engaged or slip-engaged state even during a gear shift is disclosed in, for example, Japanese Patent Laid-Open No. 1-137171. It is proposed in the bulletin.

[0003]

However, when the slip engagement state is maintained during the shift as described above, the slip amount increases during the shift, the thermal load of the lockup clutch increases, and the clutch life increases. There was a problem that it would be greatly impaired. That is, such slip control is
Generally, the clutch engagement hydraulic pressure and the like are feedback-controlled so that the rotation speed difference between the input side and the output side of the lockup clutch becomes a predetermined target rotation speed difference.
The difference in rotational speed increases due to the delay in following the change in rotational speed on the output side of the hydraulic transmission that accompanies a shift. If you increase the gain of feedback control to improve tracking,
When the change in the output side rotation speed becomes small with the end of the shift, the clutch engagement hydraulic pressure may be too high and the lockup clutch may temporarily be completely engaged.Therefore, it is possible to avoid increasing the rotation speed difference. In addition, when converging the rotation speed difference to the target rotation speed difference after the shift is completed,
It is necessary to take time and smoothly to avoid shock. In FIG. 12, slip control is performed at the time of power-on upshift with respect to the engine rotation speed NE as the input rotation speed, the turbine rotation speed Nt as the output rotation speed, the target rotation speed difference Nslip ^T thereof, and the driving torque. 6 is a time chart showing an example of a change in the case where the time t _{a to} t _b is a shift period, and the time t _{b to} t _c is a convergence period of the rotational speed difference.

The present invention has been made in view of the above circumstances, and an object thereof is to reduce the heat load of the lockup clutch while suppressing the shock at the time of shifting.

[0005]

In order to achieve the above object, the lock-up clutch may be completely engaged at the time of gear shifting, and the present invention, as shown in the claim correspondence diagram of FIG. a) A lock-up clutch that transmits engine output to an automatic transmission that is provided in parallel with a hydraulic transmission and has a plurality of shift speeds; and (b) a predetermined slip control condition is satisfied at a plurality of continuous shift speeds. In a slip control device for a vehicle lock-up clutch, which comprises a slip control means for slip-engaging the lock-up clutch in this case, (c) it is detected whether or not the shift stage of the automatic transmission is in a shift. When the slip control is performed before and after the gear shift detected by the gear shift detecting means and (d) the gear shift detecting means, the lockup clutch And having a slip limiting means for Chi the fully engaged.

[0006]

In such a slip control device, the shift detecting means detects whether or not a shift is in progress, and
When the slip control is performed before and after the shift, the lockup clutch is completely engaged during the shift by the slip limiting means. Therefore, unlike the case of releasing the lock-up clutch at the time of gear shifting, there is no shock caused by the engine blowing up at the time of disengagement or a decrease in the engine rotation speed at the time of re-engagement. The heat load on the lockup clutch is reduced as compared with the case where the engaged state is maintained. Since the slip control is generally performed in the low throttle valve opening and low vehicle speed range, the change in the rotational speed due to the shift is small, and even if the lockup clutch is completely engaged during the shift, a large shift shock does not occur. Note that it is possible to impose conditions such as the throttle valve opening degree and the vehicle speed being equal to or less than a predetermined value as a premise for completely engaging the lockup clutch during gear shift during slip control.

[0007]

As described above, according to the slip control device of the present invention, the thermal load of the lock-up clutch can be reduced while suppressing the shock at the time of shifting, and the clutch life can be improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. In FIG. 2, the output of the engine 10, which is an internal combustion engine, is transmitted from the torque converter 12 and the automatic transmission 14 which are fluid type transmission devices to the drive wheels through a differential gear device (not shown) and the like. The torque converter 12 includes a pump impeller 18 connected to the crankshaft 16 of the internal combustion engine 10, a turbine impeller 22 connected to the input shaft 20 of the automatic transmission 14, and a non-rotating via a one-way clutch 24. A stator wheel 28 fixed to the housing 26, which is a member, and a lockup clutch 32 connected to the input shaft 20 via a damper are provided. The lockup clutch 32 is disengaged when the hydraulic pressure in the release side oil chamber 36 is higher than that in the engagement side oil chamber 34 in the torque converter 12, and the lockup clutch 32 is amplified according to the input / output rotation speed ratio of the torque converter 12. While torque is transmitted at a rate,
When the oil pressure in the engagement side oil chamber 34 is higher than that in the release side oil chamber 36, the engagement state is established, and the engine output is transmitted from the crankshaft 16 to the input shaft 20 via the lockup clutch 32.

The automatic transmission 14 has three coaxially arranged parts.
Single pinion type planetary gear set 40, 42, 44
And the output shaft 46 connected to the carrier of the planetary gear set 42 and the ring gear of the planetary gear set 44. Some of the components of the planetary gear set 40, 42, 44 are integrally connected to each other, while the other part is selectively connected to each other by three clutches C ₀ , C ₁ , C ₂ , or The four brakes B ₀ , B ₁ , B ₂ , and B ₃ are selectively connected to the housing 26. Further, the three one-way clutches F ₀ , F ₁ and F ₂ are engaged with each other or with the housing 26 depending on the rotation direction. Since the torque converter 12 and the automatic transmission 14 are configured symmetrically with respect to the axis,
In FIG. 2, the lower side is omitted.

The clutches C _{0 to} C ₂ and the brake B
_{0 to} B ₃ (hereinafter, unless otherwise distinguished, the clutch C,
The brake B is a hydraulic friction engagement device that is engagement-controlled by a hydraulic actuator such as a multi-plate clutch or band brake, and hydraulic oil is supplied from the hydraulic control circuit 50 to the hydraulic actuator. Has become. The hydraulic control circuit 50 is provided with a large number of switching valves and the like, and the solenoids S1 and S2 are switched between energized and de-energized in accordance with signals from the control unit 52, whereby the hydraulic circuits are switched and the clutch C and the brake B are switched. Is selectively engaged and controlled, any one of the four forward gears is established as shown in FIG. Shift position "D",
"2" and "L" are operating ranges of the shift lever in the driver's seat. In the "D" range, shift control is performed in four stages from 1st to O / D, and in the "2" range, 1st to 3rd.
Is controlled in 3 steps up to 1s in the "L" range
The shift control is performed in two stages, t and 2nd. Further, by switching the manual shift valve in accordance with the operation of the shift lever, the brakes B ₁ and B ₃ are engaged in the 2nd of the “2” range, the 2nd of the “L” range, and the 1st of the “L” range, respectively. The engine brake is working.

The hydraulic control circuit 50 is also shown in FIG.
And a circuit for lockup control shown in FIG. The lockup relay valve 54 of FIG. 4 is brought into the ON state shown in the right half of the drawing when the lockup control oil pressure Psl of a predetermined pressure or more is applied to the oil chamber 56, and changes according to the output torque of the engine 10. The secondary hydraulic pressure PL2 regulated so as to act on the engagement side oil chamber 34 from the input port 58 via the port 60, and the release side oil chamber 36 via the ports 62 and 64 to the lockup control valve. 66 to the port 68. The lock-up control valve 66 includes an oil chamber 70 in which the engagement oil pressure Pon in the engagement-side oil chamber 34 acts, an oil chamber 72 in which the release oil pressure Poff in the release-side oil chamber 36 acts, and the lock-up control oil pressure. An oil chamber 74 in which Psl is actuated and a spring 77 for urging the spool valve element 76 toward the oil chambers 72, 74 are provided. 68 is the drain port 78 or the secondary hydraulic pressure PL2
Is communicated with the pressurizing port 80 in which the pressure is applied to regulate the release hydraulic pressure Poff, so that the differential pressure ΔP between the engagement hydraulic pressure Pon and the release hydraulic pressure Poff is adjusted according to the lockup control hydraulic pressure Psl. . That is, the lockup control oil pressure P
When sl is sufficiently high, the release hydraulic pressure Poff is set to a low pressure, the differential pressure ΔP increases, and the lockup clutch 32 is fully engaged. However, when the lockup control hydraulic pressure Psl decreases, the release is accompanied. The hydraulic pressure Poff becomes high pressure,
The differential pressure ΔP decreases, and the lockup clutch 32 is slip-engaged with the engaging force corresponding to the differential pressure ΔP. When the lockup control oil pressure Psl further decreases, the lockup relay valve 54 is turned off, the input port 58 and the port 62 communicate with each other, and the secondary oil pressure PL is reached.
2 is made to act on the release side oil chamber 36, while the port 60 and the discharge port 82 communicate with each other, the working oil in the engagement side oil chamber 34 is discharged to the oil cooler or the like, and the lockup clutch 32 is released. Becomes

The lockup control oil pressure Psl is adjusted by the linear solenoid valve 84 shown in FIG. The linear solenoid valve 84 has a constant modulator hydraulic pressure P.
m input oil 86, lockup control oil pressure Psl output port 88, drain port 90, lockup control oil pressure Psl feedback oil chamber 92, spool valve element 94 on the solenoid SL side. A solenoid S for urging the spool valve element 94 toward the spring 96.
The exciting current supplied to L is the control unit 5
2, the spool valve 94 is moved, and the output port 88 is communicated with the input port 86 or the drain port 90, so that the lockup control oil pressure Psl changes corresponding to the duty ratio SLU of the exciting current. Is output. In this embodiment, the larger the duty ratio SLU, the higher the lockup control oil pressure Psl, and the differential pressure ΔP and further the lockup clutch 32.
The engaging force of is increased. The output port 88 is connected to the input port 102 of the solenoid relay valve 100, and the B ₂ hydraulic pressure that engages the brake B ₂ is applied to the oil chamber 104, so that the spool valve element 106 has a spring 108. When moved to the ON position shown in the left half of the figure against the power, the hydraulic oil adjusted to the lockup control oil pressure Psl is transferred from the output port 110 to the lockup relay valve 54 and the lockup control valve 66. Supplied. B ₂ Oil pressure is OFF, that is, 2nd, 3rd, or O / D as apparent from FIG.
At shift speeds other than the shift speed, the spool valve element 106 is moved to the OFF position shown in the right half of the figure according to the urging force of the spring 108, the output port 110 is connected to the drain port 112, and the engagement of the lockup clutch 32 is performed. Control becomes impossible. The linear solenoid valve 84
The solenoid SL is supplied with an exciting current when the predetermined engagement condition is satisfied only in the D range 2nd, 3rd, or O / D gear, and the 2 range 2nd or 3rd gear, and the lockup clutch 32 is engaged or slip controlled.

Returning to FIG. 2, the control unit 52 includes a CPU, a RAM, a ROM, an input / output interface circuit, etc., and uses the temporary storage function of the RAM while performing signal processing according to a program stored in the ROM in advance. The solenoid S1 and S2 are switched between energized and de-energized to change the gear stage of the automatic transmission 14, and the exciting current supplied to the solenoid SL is duty-controlled to engage or slip the lockup clutch 32. Control. The control unit 52 is supplied with rotation speed signals SNt and SNo representing the rotation speed Nt of the input shaft 20, that is, the rotation speed N of the turbine impeller 22 and the rotation speed No of the output shaft 46 from the pair of rotation speed sensors 120 and 122. From the neutral start switch 124 arranged on the shift valve, the “D”,
A shift range signal SR representing a shift range such as "2" or "L" is supplied. Further, a rotation speed signal SNE representing the engine rotation speed NE is supplied from the rotation speed sensor 126 provided in the engine 10, and the engine 1
A throttle valve opening signal Sθ representing the throttle valve opening θ is supplied from a throttle sensor 128 provided in a throttle valve for adjusting the intake air amount of 0.

Next, the lockup control performed by the control unit 52 will be specifically described with reference to the flowcharts of FIGS.

FIG. 6 relates to normal lock-up control, and is executed only when the gear stage of the automatic transmission 14 is 2nd, 3rd, or O / D gear stage. Automatic transmission 14
The gear position is determined by the output state of the exciting current to the solenoids S1 and S2, for example. In step S1 of FIG. 6, it is determined whether or not the flag F1 which is set to “1” in step R6 of FIG. 7 and set to “0” in step R8 is “0”.
When 1 = 0, steps S2 and below are executed, but F1 =
In the case of 1, step S8 is executed. In step S8, the duty ratio SLU is set to 100%, and the exciting current of the solenoid SL is output at the duty ratio SLU to set the lockup control hydraulic pressure Psl to a high pressure to completely engage the lockup clutch 32. In step S2, it is set to "1" in step R10 of FIG.
It is determined whether or not the flag F2 which is set to "0" in "0" is "0",
If F2 = 0, steps S3 and below are executed, but F2
When = 1, step S9 is executed. In step S9, the duty ratio SLU is set to 0%, the lockup control hydraulic pressure Psl is set to a low pressure, and the lockup relay valve 54 is turned on.
By setting the FF state, the lockup clutch 32
Is released.

In step S3 executed when both flags F1 and F2 are "0", it is determined whether the running state of the vehicle is in the completely engaged region, and if it is not the completely engaged region, slip control is performed in step S4. Determine whether it is a region. The complete engagement region and the slip control region are determined for each shift speed using the throttle valve opening θ and the output shaft rotation speed No as parameters, as shown in FIG.
Are stored in storage means such as. The slip control area is
It is set in the low throttle valve opening and low vehicle speed (corresponding to the output shaft rotation speed No.) range that does not require a large torque. The throttle valve opening θ and the output shaft rotation speed No.
The condition regarding is equivalent to a predetermined slip control condition. Then, in the case of the complete engagement region, the step S8 is executed to completely engage the lockup clutch 32, and in the case of the slip control region, steps S5 and thereafter are executed to slip the lockup clutch 32. When the lockup clutch 32 is not in the complete engagement region or the slip control region, that is, in the disengagement region, the step S9 is executed to bring the lockup clutch 32 into the disengaged state.

In step S5 executed in the case of the slip control region, the target slip state is determined from the data map stored in advance in the RAM or the like with the throttle valve opening θ and the turbine rotation speed Nt as parameters as shown in FIG. 9, for example. The feedforward control value FWD of the obtained duty ratio SLU is calculated by map interpolation. In the target slip state, the rotation speed difference Nslip (= NE-Nt) between the engine rotation speed NE and the turbine rotation speed Nt is, for example, 5
The slip state may be a constant target rotational speed difference Nslip ^{T of} about 0 rpm, but a different target rotational speed difference Nslip ^T may be set depending on the throttle valve opening θ and the turbine rotational speed Nt. . The data map of the feedforward control value FWD is obtained in advance by experiments or the like with the duty ratio SLU at which the rotational speed difference Nslip becomes the target rotational speed difference Nslip ^T , using the throttle valve opening θ and the turbine rotational speed Nt as parameters. is there. In the next step S6, based on the deviation ΔN (= Nslip−Nslip ^T ) between the current rotation speed difference Nslip and the target rotation speed difference Nslip ^T , the feedback correction value FB for reducing the deviation ΔN is set in the PID operation or the like. It is calculated according to the feedback control formula of. Then, in step S7, the feedback correction value FB is added to the feedforward control value FWD to obtain the duty ratio SLU, and the exciting current of the solenoid SL is duty-controlled with the duty ratio SLU, whereby the lockup control hydraulic pressure Psl is obtained. Adjust the pressure. By adjusting the lockup control oil pressure Psl in this way, the lockup clutch 32 is slip-controlled so that the rotation speed difference Nslip becomes the target rotation speed difference Nslip ^T.

It should be noted that at the time of transition from full engagement to slip control, or transition from slip control to full engagement, the target rotational speed difference Nslip is set so that the driver does not feel uncomfortable due to fluctuations in the engine rotational speed NE. ^The slip state is changed smoothly by gradually changing ^T.

On the other hand, FIG. 7 relates to lock-up control during shifting of the automatic transmission 14. First, step R
1, the shift determination is performed based on a shift map stored in advance in the RAM or the like with the throttle valve opening θ and the vehicle speed V (corresponding to the output shaft rotation speed No) as parameters, as shown in FIG. In Step R2, Step R
It is determined whether or not the gear shift is determined in step 1 by, for example, a flag that indicates whether or not the next gear is set, and if it is determined that the gear shift is performed, step R is performed.
Perform 3 or less. In step R3, the output state of the exciting current for exciting the solenoids S1 and S2 is switched according to FIG. 3 to switch the gear stage of the automatic transmission 14 to the next gear stage set in step R1. After the output state of the exciting current is switched, the engaging hydraulic pressure of the clutch C and the brake B is changed to change the automatic transmission 1
It takes a considerable amount of time until the fourth gear is actually switched, and steps R4 and thereafter are executed during that time.

In step R4, it is judged whether or not the new shift stage is in the slip control region after the shift based on the set region of FIG. 8 which is determined for each shift stage. If it is not the slip control region, step R9 The following is executed, but if it is the slip control region, steps R5 and thereafter are executed. In step R9, it is determined whether or not the inertia phase has started, for example, by determining whether or not the ratio between the turbine rotation speed Nt and the output shaft rotation speed No is substantially equal to the gear ratio i _a of the gear stage before the gear shift. When the phase starts, the flag F2 is set to "1" in step R10. When the flag F2 becomes "1", the determination in step S2 of FIG. 6 becomes NO,
In step S9, the lockup clutch 32 is released. In the following step R7, it is determined whether or not the inertia phase has ended, for example, by determining whether or not the ratio of the turbine rotation speed Nt to the output shaft rotation speed No substantially matches the gear ratio i _b of the gear after the gear shift. When the inertia phase is completed, the flag F2 is set to "0" in step R9. Thus, if the slip control range is not reached after the shift, the flag F2 = 0 is set only during the inertia phase, that is, during the shift period of the automatic transmission 14, and the lockup clutch 32 is forcibly released.

In step R5, which is executed in the case of the slip control area after the shift, whether or not the slip control is currently being executed is judged from the contents of the duty ratio SLU and the flag indicating that step S7 in FIG. If control is in progress, flag F1 is set to "1" in step R6, and if slip control is not in progress, flag F1 is set in step R10.
Let 2 be "1". When the flag F1 becomes "1", the determination in step S1 of FIG. 6 becomes NO, and step S8
When the flag F2 becomes "1" while the lockup clutch 32 is completely engaged in step S9, the lockup clutch 32 is released in step S9 as described above. The flags F1 and F2 are "0" at step R8 when the inertia phase is completed and the determination at step R7 is YES.
Is set to "1" only during the inertia phase, that is, during the shift period of the automatic transmission 14. As a result, when slip control is performed before and after shifting, the flag F1 becomes "1" only during the shifting period and the lock-up clutch 32 is in the fully engaged state, but before the shifting is in the fully engaged or released state. If slip control is to be performed after shifting, flag F
2 becomes "1" and the lockup clutch 32 is released.

As described above, in the lockup control of this embodiment, when slip control is performed before and after shifting,
Since the lock-up clutch 32 is completely engaged only during the gear shift period, the engine 1 at the time of disengagement, such as when the lock-up clutch 32 is disengaged at the time of gear shift.
No shock is generated due to a rise of 0 or a decrease in the engine speed NE at the time of re-engagement, and the heat load of the lock-up clutch 32 is increased as compared with the case where the slip engagement state is maintained even during a gear shift. Is reduced and the clutch life is improved. Further, since the slip control region is set to a low throttle valve opening and a low vehicle speed region that do not require a large torque, the change range of the engine rotation speed NE and the turbine rotation speed Nt due to the shift is small, and the lock is performed during the shift. Even if the up clutch 32 is completely engaged, a large shift shock does not occur.

FIG. 11 shows the engine rotational speed NE and the turbine rotational speed N when slip control is performed according to the present embodiment before and after shifting during power-on upshift.
In the time chart showing an example of changes in t, the target rotational speed difference Nslip ^T , and the driving torque, time t _{2 to} t ₃ is a shift period, that is, an inertia phase time, and the lockup clutch 32 is completely engaged. There is. Time t _{1 to} t
₂ , t _{3 to} t ₄ are, respectively, at the time of transition from slip control to full engagement and at the transition from full engagement to slip control.
This is a period during which the target rotational speed difference Nslip ^T is gradually changed in order to prevent the driver from feeling uncomfortable due to the change in the engine rotational speed NE that accompanies the change in the slip state. On the other hand, FIG. 12 is a time chart in the case where the gear shift is performed while the slip control is being performed. The gear speed difference Nslip between the engine rotation speed NE and the turbine rotation speed Nt during the gear shift is shown.
And the heat load on the lockup clutch 32 increases.

In this embodiment, the control unit 52
Of the series of signal processing by S.
The portion that executes S5, S6, and S7 constitutes the slip control means together with the linear solenoid valve 84 and the like. Further, the portion that executes steps R2 and R7 in FIG. 7 corresponds to the shift detecting means, and the portion that executes steps R4, R5, R6 in FIG. 7 and steps S1 and S8 in FIG. 6 corresponds to the slip limiting means. .

Although one embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above-described embodiment, when the lockup clutch 32 is completely engaged before and after shifting, the flag F2 is set to "1" only during the inertia phase by executing step R9 and subsequent steps after step R4. The lockup clutch 32 is temporarily disengaged and the gearshift is performed while the lockup clutch 32 is completely engaged under certain conditions, such as when the throttle valve opening θ is equal to or less than a predetermined value. You can It is possible to perform slip engagement or complete engagement during a shift even if the shift is completely engaged before the shift and slip engaged after the shift, or if the slip engagement before the shift is completed and the shift is completely engaged after the shift. Is.

Further, in the above embodiment, step R4 and subsequent steps are executed at all shifts, but step R4 and subsequent steps are executed only in the case of a power-on upshift in which the accelerator is stepped on. You can

Further, in the above embodiment, the complete engagement area and the slip control area in FIG. 8 are set for each gear, but the throttle valve opening θ and the output shaft rotation speed are constant regardless of the kind of the gear. It is also possible to completely engage or perform slip control in the No area, and in that case there is no change in the lockup control before and after shifting, so there is no need to determine whether it is in the slip control area after shifting. If the slip control is being performed before the shift, the lockup clutch 32 may be completely engaged during the shift.

Further, in the above embodiment, when the slip control is performed before and after the gear shift, the lockup clutch 32 is always completely engaged during the gear shift, but the throttle valve opening θ and the vehicle speed V are equal to or less than a predetermined value. It is also possible to set other execution conditions such as, and if the conditions are not satisfied, the gear may be shifted in the slip state or may be released in the gear shift.

In the above embodiment, the throttle valve opening θ
The feedforward control value FWD has been calculated from a data map using the turbine rotation speed Nt as a parameter. However, instead of the throttle valve opening θ, other values corresponding to the engine output such as the intake air amount and the intake back pressure can be obtained. Parameters can be used, and correction can be performed by the changing speed of the accelerator operation amount or the changing speed of the vehicle speed V. Feedforward control value FW by fuzzy reasoning
It is also possible to obtain D.

In the above embodiment, the duty ratio SLU is feedback-controlled according to the deviation ΔN. However, the duty ratio SLU is controlled according to whether the deviation ΔN is positive or negative.
The method of correcting the duty ratio SLU is appropriately determined, for example, by increasing or decreasing by a constant value.

The hydraulic circuits and valves shown in FIGS. 4 and 5 for slip control of the lockup clutch 32 are merely examples, and various circuit configurations capable of controlling the differential pressure ΔP can be adopted. The configuration of the lockup clutch 32 itself can also be appropriately changed as necessary.

Further, in the above embodiment, the torque converter 1 is used.
Although 2 was used, other fluid transmissions such as fluid couplings could be used.

Further, although in the above-described embodiment, the automatic transmission 14 having four forward gears is provided, the automatic transmission 14 is merely an example, and the number of gears and the structure thereof may be appropriately changed.

Although not illustrated one by one, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of the present invention.

FIG. 2 is a diagram showing an example of a vehicle power transmission device having a slip control device according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating an engagement operation of a clutch and a brake for establishing each shift speed of the automatic transmission of FIG.

4 is a circuit diagram showing, together with FIG. 5, a hydraulic circuit for controlling the lockup clutch of FIG. 2.

5 is a circuit diagram showing, together with FIG. 4, a hydraulic circuit for controlling the lockup clutch shown in FIG. 2;

FIG. 6 is a flowchart illustrating an operation when controlling the lockup clutch in the embodiment of FIG.

FIG. 7 is a flowchart illustrating an operation of the automatic transmission during shifting in the embodiment of FIG.

FIG. 8 is a diagram illustrating an example of a complete engagement region and a slip control region determined in steps S3 and S4 of FIG.

9 is a diagram illustrating an example of a data map used when calculating a feedforward control value FWD in step S5 of FIG.

FIG. 10 is a diagram illustrating an example of a shift map used when making a shift determination in step R1 of FIG.

FIG. 11 is an example of a time chart showing changes in each part when the lockup clutch is controlled according to the flowcharts of FIGS. 6 and 7.

FIG. 12 is a time chart when slip control of the lock-up clutch is performed during gear shift, and is a diagram corresponding to FIG. 11.

[Explanation of symbols]

 10: Engine (engine) 12: Torque converter (fluid type transmission) 14: Automatic transmission 32: Lockup clutch 52: Control unit 84: Linear solenoid valve Steps S1, S8, R4 to R6: Slip limiting means Step S4 to S7: Slip control means Steps R2, R7: Shift detection means

Claims (1)

[Claims] 1. A lock-up clutch for transmitting engine output to an automatic transmission having a plurality of shift speeds provided in parallel with a fluid transmission, and a predetermined slip control condition being satisfied at a plurality of continuous shift speeds. In a slip control device for a vehicle lock-up clutch, which comprises a slip control means for slip-engaging the lock-up clutch in this case, a shift detection means for detecting whether or not the shift stage of the automatic transmission is in shift. And a slip limiting means for completely engaging the lock-up clutch at the time of the shift when slip control is performed before and after the shift detected by the shift detecting means. Slip control device.