JP3285960B2 - Fluid coupling fastening force control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid coupling used for an automatic transmission and the like, and more particularly to a fastening force control device for a fluid coupling having a lock-up clutch.

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted on an automobile is equipped with a fluid coupling. As this type of fluid coupling, a torque converter having a torque conversion function is generally used. It is. In this torque converter, the input and output members of the converter are directly connected in a predetermined operating region where a torque increasing operation and a shift shock absorbing operation are not required in order to reduce deterioration of engine fuel efficiency caused by so-called slip of the converter. A lock-up clutch may be provided.

In this type of torque converter (fluid coupling), if the lock-up clutch is engaged during a deceleration state, for example, by releasing the accelerator pedal, the vibration of the engine is transmitted directly to the transmission. As a result, there is a problem that the riding comfort of the vehicle deteriorates.

In order to solve such a problem, there is a case where the torque converter is controlled to a slip state in which the lock-up clutch is half-engaged in a predetermined operation region during deceleration. In other words, if the lock-up clutch is completely released during deceleration, the engine speed will drop to idle speed,
Even if the accelerator pedal is depressed during re-acceleration after coasting, a time lag occurs in the increase in engine speed and the acceleration responsiveness deteriorates.Therefore, when the lock-up clutch is slipped to completely engage the lock-up clutch, The purpose is to improve the acceleration response at the time of re-acceleration while avoiding transmission of engine vibration to the transmission. In that case, the slip control is based on the relative speed difference between the input and output members of the torque converter,
That is, feedback control is usually performed to maintain the slip amount at a predetermined target slip amount. That is, for example, a control valve for adjusting the lock-up clutch operating oil pressure is provided, and when the actual slip amount obtained from the input and output rotation speeds of the torque converter is larger than a predetermined target slip amount, the engagement force of the lock-up clutch is reduced. By driving the control valve in an increasing direction, and when the actual slip amount is smaller than the target slip amount, the control valve is driven in a direction in which the engagement force decreases, thereby engaging the lock-up clutch in the engagement direction or By operating in the release direction, the actual slip amount is maintained at the target slip amount.

[0005] By the way, in the system in which the slip amount of the torque converter is feedback-controlled at the time of deceleration as described above, when the shift from the converter region in which the lock-up clutch is completely released to the slip region in which the lock-up clutch is half-engaged, There is a problem in that the lock-up clutch is not properly engaged.

That is, as shown in FIG. 7 , in this type of torque converter A, in a normal operation state, an outer peripheral portion of a pump D connected to an engine output shaft B via a case C moves toward the turbine E side. Hydraulic oil flows, but during deceleration, the rotation speed of the turbine E is relatively higher than the rotation speed of the pump D, and the flow direction of the hydraulic oil is reversed, as shown by the arrow a in the figure. Then, hydraulic oil flows from the outer peripheral portion of the turbine E to the pump D side. Therefore, the lock-up clutch F
The hydraulic oil in the fastening chamber G formed between the turbine E and the pump D flows along with the flow a of the hydraulic oil flowing from the turbine E to the pump D side as shown by the arrow b. The phenomenon of being sucked into the pump D occurs. Then, due to this phenomenon, the pressure in the fastening chamber G decreases,
The force for pushing the lock-up clutch F against the case inner wall surface C1 is reduced. In this case, in the initial stage of deceleration, the rotation speed of the pump D (input rotation speed) rapidly drops due to the decrease of the engine rotation, while the rotation speed of the turbine E (output rotation speed) is reduced by the inertia acting on the vehicle. The rotation speed difference between the output rotation speed and the input rotation speed increases rapidly without being substantially reduced by the force. In this case, in the slip control, for example, by supplying and discharging the hydraulic pressure (release pressure) of the release chamber H formed between the lock-up clutch F and the case C, the release pressure and the engagement pressure are appropriately balanced. Is controlled so as to control the engagement force of the lock-up clutch F. Therefore, the decrease rate of the engagement pressure due to the suction action is smaller than the decrease rate of the release pressure for operating the lock-up clutch F in the engagement direction. Becomes relatively large, and the movement of the lock-up clutch F in the engagement direction is delayed, so that the rotational speed difference further increases. In particular, when the slip control is performed by the feedback control, the movement of the lock-up clutch F in the engagement direction is further delayed due to the response delay, and the rotational speed difference is further increased to one side. Therefore, the suction action of the hydraulic oil in the fastening chamber G due to the flow in the direction a is further increased, and the transition to the slip state is further delayed, and in the worst case, the fastening may not be possible.

[0007] In order to solve the problem caused by the poor responsiveness of the feedback control at the time of shifting to the slip control, the feed-forward control with excellent responsiveness is performed before the shift to the feedback control. There is an idea to control power.

For example, Japanese Patent Publication No. 1-39503 discloses that
In a torque converter in which the lock-up clutch is slip-controlled during deceleration, feed-forward control of the engagement force of the lock-up clutch is performed according to a predetermined control characteristic when shifting from the lock-up region where the lock-up clutch is completely engaged to the slip region. Along with
A technical idea of starting feedback control of the engagement force of the lock-up clutch after a predetermined period has elapsed is disclosed.

[0009]

However, in the prior art described in the above publication, the target fastening force in the feedforward control is set to a value corresponding to the target slip amount in the feedback control. At the time of shifting to, the insufficient force in the engagement chamber due to the suction action of the pump in the torque converter causes the engagement force of the lock-up clutch to be insufficient, and the above problem of poor engagement cannot be solved.

The present invention addresses the above-mentioned problem when the lock-up clutch provided in the fluid coupling is controlled to the slip state by feedback control during deceleration, and the lock-up clutch is reliably shifted from the released state to the slip state. The main purpose is to make the transition.

[0011]

According to a first aspect of the present invention, there is provided a fluid coupling fastening force control device in which a lock-up clutch that directly connects an input member and an output member of a fluid coupling is released. And a slip region for half-engaging the clutch is set,
Duty Seo fastening force of the lock-up clutch when the operating state belongs to the slip region during deceleration
In a fluid coupling fastening force control device provided with feedback control means for performing feedback control so as to maintain a predetermined target slip amount by controlling a duty ratio of a solenoid valve , an operation state shifts from the release region to the slip region. When the above duty solenoid
Release the lock-up clutch to lock the valve duty ratio
From the value in the state to the value in the fastening state
Feedforward control means for increasing rapidly in accordance with a predetermined control characteristic so also temporarily increases than engagement force corresponding to the target slip amount in the feedback control of the engagement force of the lock-up clutch by graded in width, the Deute by feedforward control means
While the duty ratio is gradually changing, the duty ratio
Duty rate limit to limit the fixed limit value
Means, input rotation speed drop amount detection means for detecting a drop amount of the input rotation speed with respect to the output rotation speed during feedforward control in the fluid coupling, and a maximum value of the drop amount detected by the detection means is a predetermined value. A control characteristic correction means for learning and correcting the predetermined gradual change width of the duty ratio with respect to the feedforward control means in a direction in which the drop amount decreases in a direction in which the drop amount decreases.

[0012] In addition, according to a second aspect of the present invention, there is provided a coupling force control device for a fluid coupling, comprising: a release area in which a lock-up clutch for directly connecting the input and output members of the fluid coupling is released; A slip region where the clutch is half-engaged is set, and when the operating state belongs to the slip region during deceleration, the engagement force of the lock-up clutch is applied to the duty solenoid valve.
A feedback control means for performing feedback control so as to maintain a predetermined target slip amount by controlling a duty ratio of the fluid coupling, wherein the operating state shifts from the release region to the slip region. The duty solenoid valve
Ratio from the value in the disengaged state of the lock-up clutch.
Gradual change in the specified width toward the value in the fastened state
Feedforward control means for increasing rapidly in accordance with a predetermined control characteristic so also temporarily increases than engagement force corresponding to the target slip amount in the feedback control of the engagement force of the lock-up clutch, the said feed
During the gradual change of the duty ratio by the forward control means,
The duty ratio does not exceed the specified limit in the direction of increasing the fastening force.
Duty ratio limiting means for limiting the rotation speed of the fluid coupling, input rotation speed drop amount detection means for detecting a drop amount of the input rotation speed with respect to the output rotation speed during feedforward control in the fluid coupling, and A predetermined gradual change of the duty ratio for the feedforward control means so that the maximum value of the drop amount falls within a predetermined range.
Control characteristic correction means for learning correction of the width is provided.

[0013]

[0014]

[0015]

According to the above arrangement, the following operation can be obtained.

That is, in any of the first and second aspects of the present invention, when the driving state shifts from the release range of the lock-up clutch to the slip range at the time of deceleration, the engagement force of the lock-up clutch becomes equal to the target slip amount in the feedback control. The feedforward control is performed according to a predetermined control characteristic so as to temporarily become larger than the corresponding fastening force. Therefore, the lock-up clutch shifts to the slip state before the input rotation speed of the fluid coupling drops too much due to the decrease of the engine rotation, and the fastening failure of the lock-up clutch due to the input rotation speed falling too much is prevented. Will be.

Although feedforward control has the advantage of excellent responsiveness, it has the disadvantage that its control characteristics are susceptible to variations in quality due to mass production and aging. In contrast, in the present invention,
When the maximum value of the drop of the input rotation speed of the fluid coupling during the feedforward control is larger than a predetermined value, the duty of the feedforward control is reduced in a direction in which the drop is reduced.
Because the predetermined gradual change of the tee rate is learned and corrected, the lock-up clutch surely shifts to the slip state without being affected by quality variation or aging due to mass production. Incorrect engagement of the lock-up clutch due to an excessive drop in the input rotation speed at the joint is reliably prevented.

In particular, according to the second invention, the predetermined gradual width of the duty ratio of the feedforward control is learned and corrected so that the maximum value of the drop amount falls within a predetermined range. In addition to the operation, the shock generated when the lock-up clutch shifts from the disengaged state to the slip state is reduced.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, referring to FIG. 1, the structure of a torque converter as a fluid coupling and a hydraulic circuit for controlling the same will be described. The torque converter 1 is fixed to one side of a case 3 connected to an engine output shaft 2. A pump 4 that rotates integrally with the engine output shaft 2, and is rotatably provided on the other side of the case 3 so as to face the pump 4. having a turbine 5 which is a scan Te <br/> over data 6 which is interposed between the pump 4 and the turbine 5, and a lock-up clutch 7 is interposed between the turbine 5 and the case 3 . And the turbine 5
Is output by a turbine shaft 8 and input to a transmission gear mechanism (not shown). When the lock-up clutch 7 is connected to the turbine shaft 8 and fastened to the case 3 The engine output shaft 2 and the turbine shaft 8 are directly connected via the case 3.

The hydraulic oil is introduced into the torque converter 1 through a lock-up valve 10 and a converter in-line 11 by a main line 9 led from an oil pump (not shown).
The lock-up clutch 7 is constantly urged in the engagement direction by the pressure (engagement pressure) of the hydraulic oil in the engagement chamber 12 formed between the turbine 5 and the lock-up clutch 7. A lock-up release line 14 led from the lock-up valve 10 is connected to a release chamber 13 formed between the case 3 and a hydraulic pressure (release pressure) from the line 14 into the release chamber 13. When the lock-up clutch 7 is released, the lock-up clutch 7 is released. Further, a converter outline 17 for sending hydraulic oil to an oil cooler 16 via a pressure holding valve 15 is connected to the torque converter 1.

On the other hand, the lock-up valve 10 has a spool 10a and a spring 10b for urging the spool 10a rightward in the drawing, and at both sides of an output port 10c to which the lock-up release line 14 is connected. A pressure regulating port 10d to which the main line 9 is connected and a drain port 10e are provided. A control line 18 for applying a pilot pressure to the spool 10a is connected to the right end of the valve 10 in the drawing.
A duty solenoid valve 20 is provided on a drain line 19 branched from the control line 18.
The duty solenoid valve 20 opens and closes the drain line 19 in a very short cycle by repeating ON and OFF at a duty ratio (ON time ratio during one ON-OFF time) D according to the input signal, thereby controlling the control line 18. Is adjusted to a value corresponding to the duty ratio D. This pilot pressure is applied to the spool 10a of the lock-up valve 10 in a direction opposing the urging force of the spring 10b, and
a, the release pressure in the lock-up release line 14 acts in the same direction as the biasing force of the spring 10b. The spool 10a moves due to the relationship between the hydraulic pressure and the biasing force, and the lock-up occurs. Release line 14
Is communicated with the main line 9 (pressure adjusting port 10d) or the drain port 10e, so that the lock-up release pressure is controlled to a value corresponding to the pilot pressure, that is, the duty ratio D of the duty solenoid valve 20. ing. Here, when the duty ratio D is a minimum value (for example, 0%), the amount of exhaust pressure from the control line 18 is maximized, and the pilot pressure or the release pressure is minimized, so that the lock-up clutch 7 is completely engaged. And
Further, when the duty ratio D is the maximum value (for example, 100%), the exhaust pressure amount becomes minimum, and the pilot pressure or the release pressure becomes maximum, so that the lock-up clutch 7 is completely released. I have. At a duty ratio D intermediate between the maximum value and the minimum value, the lock-up clutch 7 is brought into a slip state, and in this state, the release pressure is adjusted according to the duty ratio D, whereby the slip amount of the lock-up clutch 7 is adjusted. Is controlled.

Next, a control system for controlling the engagement force of the lock-up clutch 7 will be described. As shown in FIG. 2, this control system has a controller 21. The controller 21 includes a signal from a lock-up switch 22 operated by a driver, a signal from a vehicle speed sensor 23 for detecting the vehicle speed of the vehicle, and a throttle sensor 24 for detecting the throttle opening of the engine.
, A signal from an engine speed sensor 25 for detecting the engine speed, and a signal from a turbine speed sensor 26 for detecting the speed of the turbine shaft 8, based on these signals. The control of the torque converter 1 (lock-up clutch 7) is performed, or at the request of the driver.

That is, as shown in FIG. 3, the controller 21 stores the actual vehicle speed V and the throttle speed in a lock-up map in which the lock-up region L and the deceleration slip region S are set in advance using the vehicle speed and the throttle opening as parameters. The torque converter 1 is locked or slipped when the operating state belongs to the lock-up region L or the slip region S by comparing the operating state indicated by the opening degree θ. In the area C, a duty control signal is output to the duty solenoid valve 20 so as to set the converter state. Note that the deceleration slip region S is set over the middle and high vehicle speed regions.

In this embodiment, deceleration slip control when the operating state shifts from the converter region to the slip region is performed as follows in accordance with the flowchart shown in FIG.

That is, the controller 21 determines in step S
After reading various signals in step 1, the value of the slip control flag FS is determined in step S2. This slip control flag FS is set to 1 when the operating state belongs to the deceleration slip region S in the lock-up map in FIG. 3, and is reset to 0 otherwise.

When the controller 21 determines that the value of the slip control flag FS is 1, the process proceeds to step S3, and this time the feed forward control flag F
The current value of F is determined. The feedforward control flag FF is set to 1 when the operation state shifts from the converter area C to the deceleration slip area S, for example, and is reset to 0 when a predetermined time has elapsed from that point. .

The controller 21 determines in step S3 that the current value of the feedforward control flag FF is 1
When it is determined that the value of the feedforward control flag FF is satisfied, the process proceeds to step S4 to determine the previous value of the feedforward control flag FF. When it is determined that the previous value of the feedforward control flag FF is 0 indicating the non-feedforward control state, that is, when it is determined that the feedforward control is the first feedforward control, the process proceeds to step S5, and the process proceeds to step S5. Duty lower limit value D
B is compared with a value obtained by subtracting the duty reduction value ΔD from 100, and the larger of the two is set as the duty ratio D to be output to the duty solenoid valve 20, and in step S6, the actual engine speed NE is calculated from the actual engine speed NE. A value obtained by subtracting the turbine rotational speed NT is set as the minimum relative rotational speed △ NS of the pump 4 with respect to the turbine 5. Here, the duty reduction value ΔD is set to a large value so that the duty ratio D decreases rapidly.

On the other hand, when the controller 21 determines in step S4 that the previous value of the feedforward control flag FF is 1, the controller 21 proceeds to step S7.
Then, the duty lower limit value DB is compared with a value obtained by subtracting the duty reduction value △ D from the current duty ratio D, and the larger one of them is set as the duty ratio D. That is, the duty ratio D is prevented from becoming smaller than the duty lower limit value DB. The duty lower limit value DB has been experimentally determined in advance so that the lock-up clutch 7 reliably shifts from the disengaged state to the engaged state.

Next, the controller 21 proceeds to step S8.
To calculate the relative rotational speed △ N of the pump 4 with respect to the turbine 5 at that time by subtracting the turbine rotational speed NT from the actual engine rotational speed NE, and set in step S6 in step S6. The minimum relative rotational speed {NS} is compared with the relative rotational speed {N determined in step S8, and the current relative rotational speed {
If N is smaller than the minimum relative rotation speed △ NS, step S10 is executed to replace the relative rotation speed △ N with the minimum relative rotation speed △ NS. That is, the maximum value of the amount of decrease in the rotation speed of the pump 4 with respect to the rotation speed of the turbine 5 during the feedforward control is determined.

Then, the feedforward control flag F
When F is switched to 0 indicating the non-feedforward control state, the flow shifts to feedback control as described later.

The progress up to the transition to the feedback control will be described with reference to the time chart of FIG.

That is, when the operation state shifts from the converter area C to the deceleration slip area S as shown by the arrow (a) in FIG. 3 by the full release operation of the accelerator pedal, the slip control flag FS and the feedforward control flag FF Are respectively switched from 0 to 1 and the control is shifted to the feedforward control, and the duty ratio D is rapidly reduced according to the duty reduction value △ D until the duty ratio D reaches the duty lower limit value DB. In this case, since the relationship between the duty ratio D and the engagement force of the lock-up clutch 7 is set so that the engagement force increases as the duty ratio D decreases as described above, Accordingly, the fastening force increases rapidly. Accordingly, the engine speed NE passes through the turbine speed NT and temporarily decreases and then increases again as shown by the symbol (a). As a result, the lock-up clutch 7 shifts to the slip state without fail, and a poor connection due to the engine speed NE dropping too much is avoided.

In this embodiment, when the feedforward control is completed, the following control operation is performed.

That is, when the controller 21 returns to the flowchart of FIG. 4 and determines in step S3 that the current value of the feedforward control flag FF is 0 indicating the non-feedforward control state, it branches to step S11. As in step S4, the previous value of the feedforward control flag FF is determined. Then, when it is determined that the previous value of the feedforward control flag FF is 1 indicating the feedforward control state, that is, when it is determined that the feedforward control has been completed, step S12 is executed to execute the control for the feedforward control. After performing the characteristic learning correction, step S13 is executed to shift to a predetermined feedback control. That is, the controller 21 calculates, for example, the relative rotation speed ΔN of the pump 4 with respect to the turbine 5 from the engine rotation speed NE and the turbine rotation speed NT, and calculates the relative rotation speed ΔN as a predetermined target relative rotation speed (target slip speed). amount)
If it is larger than ΔN0, the lock-up clutch 7
In the direction in which the fastening force of the lock-up valve 10 increases.
When the relative rotation speed ΔN is smaller than the target relative rotation speed ΔN0, the lock-up valve 10 is driven in a direction in which the engagement force is reduced, thereby engaging the lock-up clutch 7 in the engagement direction. Alternatively, it is operated in the release direction to maintain the relative rotation speed of the pump 4 with respect to the turbine 5 at the target relative rotation speed.

In this embodiment, the learning correction processing is performed as follows in accordance with the flowchart of FIG.

That is, the controller 21 determines in step S
At 21, it is determined whether or not the minimum relative rotational speed △ NS of the pump 4 with respect to the turbine 5 during the feedforward control is greater than a predetermined allowable lower limit △ N1 set on a lower rotational speed side than the turbine rotational speed NT. . The allowable lower limit value △ N1 is a fluctuation value that changes so as to be at a constant interval with respect to the turbine rotational speed NT as shown in FIG. Then, the controller 21, when it is determined that the minimum relative rotational speed △ N S is not greater than the allowable lower limit value △ N1, the duty reduction value by performing the steps S22 △ predetermined duty reduction value correction value D △ D0 Is added.

On the other hand, when the controller 21 determines in the step S21 that the minimum relative rotation speed ΔNS is larger than the allowable lower limit value ΔN1, the controller 21 proceeds to the step S21.
23, it is determined whether or not the relative rotation speed NS is smaller than a predetermined allowable upper limit value N2 (> N1). Also in this case, the allowable upper limit value ΔN 2 is set to a lower rotation speed side than the turbine rotation speed NT, and
It changes so as to be at a constant interval with respect to the turbine speed NT. Then, the controller 21 determines the minimum relative rotational speed △
NS is when it is determined to be not less than the allowable upper limit △ N2 executes a step S24 to subtract the duty reduction value correction value △ D 0 from the duty reduction value △ D.

By learning and correcting the duty reduction value ΔD, the following operation and effect can be obtained.

That is, the minimum relative rotational speed ΔN of the pump 4 with respect to the turbine 5 during feedforward control
S, that is, the maximum value of the drop amount of the engine speed NE is shown in FIG.
(B), the upper limit line L defined by the allowable lower limit value ΔN1 and the allowable upper limit value ΔN2.
2 and L1, the duty ratio D is reduced in accordance with the duty reduction value △ D ′ (> △ D) in the next feedforward control. Changes with a steeper slope than the previous time, as shown by the symbol (c). As a result, the engagement force of the lock-up clutch 7 is increased more rapidly than the previous time, and accordingly, the engine speed NE is not excessively reduced, and the engagement failure of the lock-up clutch 7 is more reliably prevented. Will be.

On the other hand, when the maximum value of the drop amount of the engine speed NE is larger than the shaded area sandwiched by the upper and lower lines L2 and L1, as shown by the symbol (d).
In the next feedforward control, the duty ratio D is reduced in accordance with the duty reduction value △ D ”(<） D). Therefore, the duty ratio D is more gradual than the previous time, as indicated by the symbol (e). As a result, the engagement force of the lock-up clutch 7 is gradually increased with respect to the previous time.
Excessive fastening shock is also prevented.

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

As described above, according to the present invention, the engagement force control of the fluid coupling in which the lock-up clutch provided in the fluid coupling is controlled to the slip state by the feedback control in the predetermined operation region at the time of deceleration. In the device, when the operating state shifts from the release area of the lock-up clutch to the slip area during deceleration, the engagement force of the lock-up clutch temporarily becomes larger than the engagement force corresponding to the target slip amount in the feedback control. Since the feedforward control is performed in accordance with the predetermined control characteristics, the lock-up clutch shifts to the slip state before the input rotation speed of the fluid coupling drops too much due to the decrease of the engine rotation.
This prevents the lock-up clutch from being poorly engaged due to the input speed dropping too much.

In particular, according to the present invention, when the maximum value of the drop amount of the input rotational speed of the fluid coupling during the feed forward control is larger than a predetermined value, the duty ratio of the feed forward control is reduced in a direction in which the drop amount decreases. Predetermined grading of
Because the width is learned and corrected, the lock-up clutch shifts to the slip state without being affected by quality variation or aging due to mass production, and the input rotation speed drops too much. Poor fastening of the lock-up clutch is reliably prevented.

Further, as in the embodiment, by learning and correcting a predetermined gradual change width of the duty ratio of the feedforward control so that the maximum value of the drop amount falls within a predetermined range, in addition to the above-described operation, Shock generated when the lock-up clutch is shifted from the disengaged state to the slip state is also reduced.

[Brief description of the drawings]

FIG. 1 is a drawing showing a structure of a torque converter and a hydraulic control circuit thereof.

FIG. 2 is a control system diagram of a torque converter.

FIG. 3 is a map showing a control area.

FIG. 4 is a flowchart illustrating slip control.

FIG. 5 is a time chart illustrating the operation of the embodiment.

FIG. 6 is a flowchart illustrating learning correction of control characteristics used for feedforward control.

FIG. 7 is an outline of a torque converter showing a conventional problem .
It is a block diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Torque converter 2 Engine output shaft 7 Lock-up clutch 8 Turbine shaft 10 Lock-up valve 20 Duty solenoid valve 21 Controller 25 Engine rotation sensor 26 Turbine rotation sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-141528 (JP, A) JP-A-2-163566 (JP, A) JP-A-1-98760 (JP, A) JP-A-4- 64768 (JP, A) JP-A-1-279157 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 61/14

Claims (2)

(57) [Claims] A release area in which a lock-up clutch that directly connects an input member and an output member of a fluid coupling is released, and a slip area in which the clutch is half-engaged are set. Deyute the engagement force of the lock-up clutch when belonging to the area
A fluid coupling fastening force control device provided with feedback control means for performing feedback control so as to maintain a predetermined target slip amount by controlling a duty ratio of an solenoid valve. When the duty shifts from the release area to the slip area, the duty
The duty ratio of the solenoid valve locks up the clutch
From the value in the released state to the value in the engaged state
Feedforward control means for gradually increasing the engagement force of the lock-up clutch in accordance with a predetermined control characteristic so as to temporarily increase the engagement force of the lock-up clutch by temporarily changing the engagement force corresponding to the target slip amount in the feedback control by gradually changing the engagement force with a constant width ; , The feed forward control means
While the duty ratio is gradually changing, the duty ratio
Duty ratio that limits the specified value to not exceed
Limiting means, input rotation speed drop amount detection means for detecting a drop amount of the input rotation speed with respect to the output rotation speed during feedforward control in the fluid coupling, and a maximum value of the drop amount detected by the detection means is predetermined. A control characteristic correction means for learning and correcting a predetermined gradual change width of the duty ratio with respect to the feedforward control means in a direction in which the drop amount decreases when the value is larger than the value. Force control device for a fluid coupling. 2. A disengagement region in which a lock-up clutch that directly connects the input and output members of the fluid coupling is released, and a slip region in which the clutch is half-engaged are set. Deyute the engagement force of the lock-up clutch when belonging to the area
A fluid coupling fastening force control device provided with feedback control means for performing feedback control so as to maintain a predetermined target slip amount by controlling a duty ratio of an solenoid valve. When the duty shifts from the release area to the slip area, the duty
The duty ratio of the solenoid valve locks up the clutch
From the value in the released state to the value in the engaged state
Feedforward control means for gradually increasing the engagement force of the lock-up clutch in accordance with a predetermined control characteristic so as to temporarily increase the engagement force of the lock-up clutch by temporarily changing the engagement force corresponding to the target slip amount in the feedback control by gradually changing the engagement force with a constant width ; , The feed forward control means
While the duty ratio is gradually changing, the duty ratio
Duty ratio that limits the specified value to not exceed
Limiting means, input rotation speed drop amount detection means for detecting a drop amount of the input rotation speed with respect to the output rotation speed during feedforward control in the fluid coupling, and a maximum value of the drop amount detected by the detection means is predetermined. The above data for the feed-forward control means to be within the range.
And a control characteristic correction means for learning and correcting a predetermined gradual change width of the duty ratio .