JPH11108176A - Fastening force control device for lock up clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve shift feeling at the time of a shift by controlling fastening force of a clutch so as to increase the fastening force at the time of a later period larger than that of an earlier period of a shift operation, when a lock up clutch is controlled from a lock up condition into a slip condition at the time of prescribed up shift change. SOLUTION: When shift operation is transferred from torque phase to an inertia phase and respective reduction of engine and turbine rotating speed is started, a duty ratio D of a control signal outputted to a duty solenoid valve of fastening force regulating means is reduced to a first duty ratio D1. After that, when a slip rate (engine rotating speed-turbine rotating speed) is larger than a prescribed value S1, the duty ratio D is changed into a second duty ratio D2. Slip of the lock up clutch is promoted at an earlier period of shift operation, and it is rapidly transferred in a prescribed slip condition, and thereby, it is possible to suppress racing of engine rotating speed when shift operation is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock-up clutch engagement force control device provided in a torque converter of an automatic transmission, and belongs to the technical field of a vehicle automatic transmission.

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted on a vehicle combines a torque converter and a transmission gear mechanism,
The power transmission path of the transmission gear mechanism is configured to be switched by a selective operation of a plurality of friction elements such as a clutch and a brake to automatically shift to a predetermined shift speed. A lock-up clutch may be provided to directly connect an input member from the engine and an output member to the transmission gear mechanism.

The lock-up clutch is controlled in accordance with the driving state at that time according to a map set in advance using, for example, the vehicle speed of the vehicle and the throttle opening of the engine as parameters. In the low-speed load region, the input and output members are completely released (converter state), and in the low-load high-speed region where fuel efficiency is important, the two members are completely engaged (lockup state). For example, in a predetermined operation range such as a low-load low-speed range or the like, in order to secure vibration while absorbing good fuel economy performance, the two members are fastened in a state of slipping at a predetermined relative rotation speed ( (Slip state).

As disclosed in Japanese Patent Application Laid-Open No. S61-99763, for example, the slip state is controlled by adjusting the hydraulic pressure for operating the lock-up clutch by using a duty solenoid valve or the like to reduce the engagement force of the clutch. Usually, the control is performed so that the relative rotation speed between the input and output members of the torque converter, that is, the slip amount, is made to coincide with a preset target slip amount.

[0005]

By the way, even in the operation region (lock-up region) in which the above-mentioned lock-up clutch is completely engaged, the clutch may be in a slip state at the time of shifting. That is, if the gearshift operation is performed in the lockup state, at the end of the gearshift operation, a torsional vibration called swingback may occur in the drive system including the torsion damper provided in the lockup clutch, Depending on the type of shift, this may cause the shift feeling to deteriorate during the shift.

Therefore, at the time of a predetermined shift such as a 3-4 upshift during acceleration performed in the lockup region, the lockup clutch is controlled to slip only during the shift operation. The torsional vibration is absorbed by the slip of the lock-up clutch, and the deterioration of the shift feeling as described above is avoided.

In this case, this control is performed by shifting the lock-up clutch from the lock-up state to the slip state at the start of the shift, and at the start of the shift, the operating pressure for releasing the lock-up clutch is controlled by a duty solenoid valve or the like. The supply control is started or the control for lowering the operating pressure for fastening is started. At this time, the following problem occurs due to a delay in response of a change in the operating pressure to the output of the control signal. It is.

That is, as shown in FIG. 9, an upshift operation during acceleration is started, the operation shifts from a torque phase to an inertia phase, and the turbine speed, which is the engine speed and the output speed of the torque converter, is changed. When the number starts to decrease (see reference numeral a), the duty ratio of the control signal output to the duty solenoid valve (1
100% of ON-OFF cycle)
To a predetermined value α to raise the release pressure of the lock-up clutch, thereby reducing the engaging force of the clutch and shifting from the lock-up state to the slip state. Even if the duty ratio of the control signal output to the solenoid valve is rapidly reduced, the release pressure does not rise immediately, but its rise is delayed (see reference symbol A).

Therefore, the lock-up clutch is maintained in a substantially completely engaged state in the first half of the shifting operation (see reference symbol c), and suddenly starts to slip in the second half of the shifting operation, and the accelerator pedal is released. Since the stepped-up acceleration is being performed, when the speed change operation is completed and the turbine speed is reduced to the speed after the speed change is completed, a so-called increase in the engine speed occurs (see reference numeral d). This phenomenon gives the occupant an uncomfortable feeling, and the shift feeling at the time of the shift is remarkably deteriorated.

SUMMARY OF THE INVENTION The present invention addresses the above-described problem in controlling the lock-up clutch to a slip state during a predetermined shift in a lock-up region, and an object of the present invention is to improve the shift feeling during the shift. And

[0011]

In order to solve the above problems, the present invention uses the following means.

First, the invention described in claim 1 of the present application (hereinafter, referred to as a first invention) includes a lock-up state in which the input member and the output member of the torque converter are completely fastened and a converter state in which the input member and the output member are completely released. A lock-up clutch selectively controlled to one of slip states in which the members are relatively rotatably fastened, a fastening force adjusting means for adjusting a fastening force of the clutch, and a value relating to a slip amount between the two members. Traveling state detection means for detecting the traveling state of the vehicle, and controlling the state of the lock-up clutch according to the traveling state detected by the traveling state detection means,
A lock-up clutch engagement force control device for an automatic transmission, comprising: a lock-up control unit that controls the engagement force adjustment unit so that the clutch is brought into a slip state during a predetermined upshift performed in a lock-up state. In the above, when the lock-up control means controls the lock-up clutch from the lock-up state to the slip state during the predetermined up-shift, the engagement force of the clutch is larger in the latter half of the shift operation than in the first half. Thus, the present invention is characterized in that the above-mentioned fastening force adjusting means is controlled.

Further, the invention according to claim 2 (hereinafter referred to as a second invention)
The invention relates to a lock-up clutch engagement force control device for an automatic transmission similar to the first invention.
The engagement force adjusting means adjusts the engagement force of the lock-up clutch based on the value of the control signal from the lock-up control means, and the lock-up control means sets the lock-up clutch in the lock-up state during the predetermined upshift. And controlling the value of the control signal output to the engagement force adjusting means so that the engagement force of the clutch is greater in the latter half of the shifting operation than in the first half of the shifting operation. .

Further, the invention according to claim 3 (hereinafter referred to as a third invention) comprises a vehicle speed detecting means for detecting a value relating to a vehicle speed, an engine load detecting means for detecting a value relating to an engine load, a vehicle speed and an engine load. A shift control unit that controls a shift speed based on a shift characteristic preset according to a value related to a vehicle speed and a value related to a vehicle speed and an engine load detected by the two detection units; and an input member and an output member of a torque converter. A lock-up clutch selectively controlled to one of a completely engaged lock-up state, a completely released converter state, and a slip state in which both members are relatively rotatably engaged, and an engagement for adjusting the engagement force of the clutch Force adjustment means, a lock-up characteristic preset according to values relating to vehicle speed and engine load, and a lock-up characteristic detected by the two detection means. The state of the lock-up clutch is controlled based on the speed and the engine load, and the lock-up clutch is brought into a slip state when a predetermined upshift is performed by the shift control means in the lock-up state. A lock-up clutch engagement force control device for an automatic transmission, comprising: a lock-up control unit that controls the engagement force adjustment unit; wherein the lock-up control unit locks the lock-up clutch during the predetermined upshift. When controlling from the up state to the slip state, the engaging force adjusting means is controlled such that the engaging force of the clutch is larger in the latter half of the shifting operation than in the first half.

Further, the invention according to claim 4 (hereinafter referred to as a fourth aspect)
The lock-up control means according to any one of the first to third inventions, wherein the lock-up control means controls the lock-up clutch from the lock-up state to the slip state at the time of the predetermined up-shift speed change. When controlling so that the latter half of the shifting operation is larger than the latter half of the shifting operation, the late fastening force of the shifting operation is set to an intermediate value between the fastening force of the first half and the fastening force in the lock-up state, It is characterized in that the value of the fastening force adjusting means or a control signal output to the fastening force adjusting means is controlled.

The invention according to claim 5 (hereinafter referred to as the fifth invention)
The lock-up control means according to any one of the first to fourth inventions, when the lock-up clutch controls the lock-up clutch from the lock-up state to the slip state at the time of the predetermined up-shift, when the torque converter is engaged.
After the slip amount between the output members becomes equal to or more than a predetermined value, the value of the engagement force adjusting means or the control signal output to the engagement force adjustment means is controlled so that the engagement force of the lock-up clutch becomes larger than before. It is characterized by doing.

According to a sixth aspect of the present invention, the lock-up control means locks the lock-up clutch during a predetermined upshift. When controlling from the up state to the slip state, after the rotational speed of the output member of the torque converter has decreased to a rotational speed higher than the rotational speed after the end of the shift by a predetermined rotational speed, the engagement force of the lock-up clutch becomes lower than before. It is characterized in that the value of the fastening force adjusting means or the control signal output to the fastening force adjusting means is controlled so as to increase.

According to a seventh aspect of the present invention, the lock-up control means locks the lock-up clutch during a predetermined up-shift operation. When controlling from the up state to the slip state, turning on the torque converter,
When the slip amount between the output members becomes a predetermined value or more,
After the earlier one of the times when the rotation speed of the output member of the torque converter has decreased to the rotation speed higher than the rotation speed after the end of the shift by a predetermined rotation speed, the engagement force of the lock-up clutch becomes larger than before. Thus, the present invention is characterized in that the value of the fastening force adjusting means or the control signal output to the fastening force adjusting means is controlled.

With the above configuration, the following effects can be obtained according to the present invention.

First, according to the first aspect, when a predetermined upshift is performed in the lockup state,
When the lock-up clutch is controlled to be in the slip state, the engagement force of the clutch is controlled so as to be relatively small in the first half of the shifting operation and to be larger in the second half of the shifting operation. Is promoted, and the state immediately shifts to a predetermined slip state.

[0021] Therefore, in the first half of the speed change operation, the vehicle is almost completely engaged, and the engine speed at the end of the speed change operation, such as when suddenly starting to slip in the second half, is suppressed.

Further, according to the second aspect, the engagement force adjusting means adjusts the engagement force of the lock-up clutch based on the value of a control signal from the lock-up control means, such as a duty solenoid valve. The operation of the first invention is obtained in the automatic transmission having the structure described above.
According to the third invention, the shift control and the lock-up control are
In an automatic transmission performed based on characteristics preset in accordance with values related to vehicle speed and engine load and values related to vehicle speed and engine load detected by each detection unit,
The operation of the first invention is obtained.

Further, according to the fourth aspect of the invention, when the lock-up clutch is controlled from the lock-up state to the slip state during the predetermined up-shift in the lock-up state, the engaging force of the clutch firstly changes the speed of the shift operation. Is controlled in such a manner that the value becomes larger than the former period but smaller than the lock-up state in the latter period of the shifting operation, so that the shifting operation is performed in the same manner as in the first to third inventions. The slip of the lock-up clutch is promoted in the first half, and the torsional vibration due to the above-mentioned swing back at the end of the shift is effectively suppressed.

According to the fifth aspect of the present invention, the control point in time at which the engagement force of the lock-up clutch is shifted from a small state in the first half of the shift operation to a large state in the second half of the shift operation is defined as a point in time when the slip amount exceeds a predetermined value. According to the sixth aspect of the invention, this time is the time when the rotational speed of the output member of the torque converter has decreased to a rotational speed higher by a predetermined rotational speed than the rotational speed after the end of the speed change. The transition from the small state to the large state is performed at an appropriate timing.

According to the seventh aspect of the present invention, the control point in time at which the engagement force of the lock-up clutch is shifted from a small state in the first half of the shifting operation to a large state in the latter half of the shifting operation is defined as a point in time when the slip amount exceeds a predetermined value. The time at which the rotational speed of the output member of the torque converter has decreased to a rotational speed higher by a predetermined rotational speed than the rotational speed after the end of the gear shift is the earlier one, and therefore, the state in which the fastening force is small at an appropriate timing without delay. Will be shifted to a large state.

[0026]

Embodiments of the present invention will be described below.

First, the overall mechanical structure of the automatic transmission 10 according to the present embodiment will be described with reference to the skeleton diagram of FIG.

The automatic transmission 10 includes, as main components, a torque converter 20 and a transmission gear mechanism driven by an output of the converter 20 (hereinafter, the engine side is referred to as front and the anti-engine side as rear). And a plurality of friction elements 51 to 40 such as clutches and brakes for switching a power transmission path formed by the planetary gear mechanisms 30 and 40.
55 and a one-way clutch 56, whereby the first to fourth speeds in the D range and the first to third speeds in the S range are provided.
The first and second speeds in the speed range and the L range and the reverse speed in the R range are obtained.

The torque converter 20 is a pump 2 fixed in a case 21 connected to the engine output shaft 1.
2 and the pump 22
And a stator 25 interposed between the pump 22 and the turbine 23 and supported by the transmission case 11 via a one-way clutch 24 to increase the torque. And a lock-up clutch 26 provided between the case 21 and the turbine 23 and directly connecting the engine output shaft 1 and the turbine 23 via the case 21. And
The rotation of the turbine 23 is output to the planetary gear mechanisms 30 and 40 via a turbine shaft 27.

Here, behind the torque converter 20, an oil pump 12 driven by the engine output shaft 1 via a case 21 of the torque converter 20 is arranged.

On the other hand, the first and second planetary gear mechanisms 30,
Reference numeral 40 denotes sun gears 31 and 41, and a plurality of pinions 32 ... 32 meshed with the sun gears 31 and 41.
42 ... 42 and these pinions 32 ... 32, 42 ... 4
2 and pinion carriers 33, 43, and internal gears 34, 44 meshing with the pinions 32,.

The turbine shaft 27 and the first
A forward clutch 51 is provided between the planetary gear mechanism 30 and the sun gear 31, a reverse clutch 52 is provided between the turbine shaft 27 and the sun gear 41 of the second planetary gear mechanism 40, and a turbine shaft 27 is provided with the second planetary gear mechanism. A 3-4 clutch 53 is interposed between the pinion carrier 43 and the pinion carrier 40, and a 2-4 brake 54 for fixing the sun gear 41 of the second planetary gear mechanism 40 is provided.

Further, the internal gear 34 of the first planetary gear mechanism 30 and the pinion carrier 43 of the second planetary gear mechanism 40 are connected, and a low reverse brake 55 and a one-way clutch are provided between the internal gear 34 and the transmission case 11. 5
6 are arranged in parallel, and the pinion carrier 33 of the first planetary gear mechanism 30 and the internal gear 44 of the second planetary gear mechanism 40 are connected, and the output gear 13 is connected to these.

The output gear 13 is meshed with the first intermediate gear 62 on the idle shaft 61 constituting the intermediate transmission mechanism 60, and the second intermediate gear 63 on the idle shaft 61 and the differential gear. The input gear 71 of the differential gear 70 meshes with the rotation of the output gear 13 and is input to the differential case 72 of the differential 70.
The left and right axles 73, 74 are driven via the zero.

The relationship between the operating states of the friction elements 51 to 55 such as the clutches and brakes and the one-way clutch 56 and the gears is summarized in Table 1 below.

[0036]

[Table 1] Note that the torque converter 20 shown in the skeleton diagram of FIG. 1 is specifically configured as shown in FIG. 2. The torque converter 20 will be described in detail. A pump 22 composed of a number of blades provided integrally with the case 21 in a half of the case 21 on the opposite side to the engine, Pump 22
A turbine 23, which is composed of a large number of blades, and is disposed in an inner peripheral portion between the pump 22 and the turbine 23, and is supported by the transmission case 11 via a one-way clutch 24 and has a predetermined shape. And a stator 25 composed of a large number of blades rotatable only in the direction. The boss 23a of the turbine 23 is spline-coupled to the turbine shaft 27.
, The rotation of the turbine 23 is taken out to the side opposite to the engine.

In the case 21, the turbine 2
A lock-up clutch 26 that rotates integrally with the motor 3 and is slidable in the axial direction with respect to the turbine 23 is built in. The lock-up clutch 26 is disposed so as to face the flat portion 21a on the engine side in the case 21. When the lock-up clutch 26 is fastened to the case flat portion 21a, the lock-up clutch 26 Thus, the engine output shaft 1 and the turbine shaft 27 are connected.

The lock-up clutch 26
Is a chamber behind the clutch 26 in the case 21;
That is, the chamber is urged in the fastening direction by the pressure of the hydraulic oil in the rear chamber 26a with respect to the case flat portion 21a, and is provided between the lock-up clutch 26 and the case flat portion 21a, that is, the front chamber. The slip is released by the operating pressure supplied to the front chamber 26b, and the slip state is controlled by adjusting the operating pressure supplied to the front chamber 26b.

Here, the structure of the control portion of the lock-up clutch 26 in the hydraulic circuit provided in the automatic transmission 10 will be briefly described as shown in FIG.
The hydraulic circuit 80 is provided with a lock-up control valve 81 for controlling the supply and discharge of operating pressure to the rear chamber 26a and the front chamber 26b of the lock-up clutch 26, and the valve 81 is adjusted to a constant pressure from a hydraulic source. A line 82 for supplying the converter pressure, a line 83 for supplying the pilot pressure, and a duty solenoid valve 8.
4 is connected to a line 85 for supplying the control pressure generated in Step 4.

When the pilot pressure is not supplied from the line 83, the spool 81a is positioned on the right side in the drawing by the urging force of the spring 81b as shown in FIG. The clutch 26 is released by supplying it to the front chamber 26b of the lock-up clutch 26 via the pump 86 (in the converter state). When the pilot pressure is supplied, the spool 81a The converter pressure is supplied to the rear chamber 26a of the lock-up clutch 26 via the line 87 by moving to the left on the drawing against the urging force of the clutch 81b, whereby the clutch 26 is engaged. (Locked up).

In this engaged state, the control pressure generated by the duty solenoid valve 84 and supplied through the line 85 is supplied to the front chamber 26b through the lock-up control valve 81 and the line 86. The control pressure is supplied to the front chamber 26b while a constant converter pressure is being supplied to the rear chamber 26a of the lock-up clutch 26, so that the engagement force of the clutch 26 or the pump 22 of the torque converter 20 The amount of slip with the turbine 23 is controlled according to the magnitude of the control pressure (slip state).

On the other hand, as shown in FIG. 3, the automatic transmission 10 is provided with a control unit 100 for controlling the shift and controlling the lock-up clutch 26 as described above. A signal from a vehicle speed sensor 101 for detecting a vehicle speed of the vehicle, a throttle opening sensor 1 for detecting an engine throttle opening
02, a signal from a shift position sensor 103 for detecting a shift position (range) selected by the driver, and a signal from an engine speed sensor 104 for detecting an engine speed which is an input speed of the torque converter 20. A signal, a signal from a turbine speed sensor 105 that detects the turbine speed, which is the output speed of the torque converter 20, and the like are input.

The control unit 100
Sets the gear position based on the traveling state of the vehicle indicated by the signals from the sensors 101 to 105, in particular, the vehicle speed and the throttle opening, and a shift map previously set using the vehicle speed and the throttle opening as parameters. Then, a control signal is output to a plurality of shift solenoid valves 106... 106 provided in the hydraulic circuit 80 so that the shift speed can be obtained.

The control unit 100
Similarly, a lock-up map such as that shown in FIG. 4 is set in advance by using the traveling state of the vehicle indicated by the signals from the sensors 101 to 105, in particular, the vehicle speed and the throttle opening, and the vehicle speed and the throttle opening as parameters. The control region of the lock-up clutch 26 is determined on the basis of the above conditions, and the lock-up of the hydraulic circuit 80 is controlled such that the lock-up clutch 26 is controlled to one of a converter state, a lock-up state, and a slip state according to the region. A control signal is output to the up duty solenoid valve 84.

In this case, as shown in FIG. 4, the lockup area set on the high vehicle speed side includes the 3-4 upshift shift line set in the shift map. Is performed in the lock-up state, at this time, the control unit 100 performs control to shift the lock-up clutch 26 to the slip state.

Next, the control of the lock-up clutch 26 by the control unit 100, in particular, the operation of the slip control during the 3-4 upshift in the lock-up state will be specifically described.

In the slip state, as described above, while the constant converter pressure is being supplied to the rear chamber 26a of the lock-up clutch 26, the front chamber 2
When the control pressure supplied to the lock-up clutch 26 is adjusted by the duty solenoid valve 84, the engagement force or slip amount of the lock-up clutch 26 is controlled.
In that case, the duty solenoid valve 84
The smaller the duty ratio of the input control signal is, the higher the generated control pressure is, and accordingly, the engagement force of the lock-up clutch 26 is reduced. Therefore, in the control for shifting from the lockup state to the slip state, the duty ratio is reduced.

Now, the operating state is in the lock-up area of the map shown in FIG. 4, and in this state, the operating state crosses the 3-4 upshift line and the shift control of the 3-4 upshift is started. Shall be.

At this time, the control unit 100
Starts the lock-up control shown in the flowchart of FIG. 5 in parallel with the above-mentioned shift control.
It is determined whether the shift operation has shifted from the torque phase to the inertia phase. Then, as indicated by reference numeral in FIG. 6, when the inertia phase is started and the engine speed and the turbine speed start to decrease,
In step S2, the duty ratio D of the control signal output to the duty solenoid valve 84 is reduced from 100% in the previous lock-up state to a predetermined first duty ratio D1.

As a result, a control pressure corresponding to the first duty ratio D1 is supplied to the front chamber 26b of the lock-up clutch 26, and the engagement force of the clutch 26 changes from the fully engaged state to the first duty ratio D1. The value is reduced to the corresponding value, and the clutch 26 shifts to the slip state.

After that, the control unit 100
In step S3, it is determined whether or not the slip amount S (engine speed-turbine speed) has become larger than a predetermined value S1 (see FIG. 6), or the turbine speed Nt is determined by a predetermined speed n from the speed Nt1 after the shift is completed. It is determined whether or not the rotation speed is lower than the rotation speed (see FIG. 6), and if either of them is satisfied, step S4 is executed, and the duty ratio D is set to be larger than the first duty ratio D1 and to be larger than 100%. Switches to a small second duty ratio D2, and outputs a control signal of the duty ratio D2 to the duty solenoid valve 84.

After that, steps S5 and S6 are executed, and the duty ratio D is increased at a constant increase rate d1 until the predetermined time T elapses after the duty rate D is switched to the second duty rate D2. At the same time, if the predetermined time T has elapsed, steps S7 and S8 are executed, and the duty ratio D is set to an increase rate d2 larger than the increase rate d1.
And increase until it reaches 100%.

Thus, as shown in FIG. 6, after the duty ratio D is reduced from 100% to the first duty ratio D1 at the start of the inertia phase, the duty ratio D becomes larger than the first duty ratio D1 during the shifting operation. 2 is changed to the duty ratio D2, and thereafter, is gradually increased at an increasing rate d1 until a predetermined time elapses, and is further increased at a further increasing rate d2 when a predetermined time T elapses, and is changed after the shifting operation is completely completed. It will be returned to the same 100% as before.

As shown in FIG. 7, the first duty ratio D1 output at the start of the inertia phase and the second duty ratio D2 switched from the first duty ratio D1 during the shifting operation are both: The larger the engine torque is, the larger the value is, so that the lock-up clutch 26 is likely to slip. If the engine torque is large, the engagement force is increased, so that the slip state is almost constant regardless of the torque. Is obtained.

As shown in FIG. 8, the turbine speed Nt at the time of switching the duty ratio from the first duty ratio D1 to the second duty ratio D2 during the shift operation is added to the rotation speed Nt1 after the shift is completed. The predetermined rotational speed n is set to a larger value as the turbine rotational speed before the shift is higher, so that the duty ratio D is switched without delay even at high speed.

As described above, at the start of the inertia phase at the time of the 3-4 upshift in the lock-up state, the control is output to the duty solenoid valve 84 so that the lock-up clutch 26 shifts to the slip state. The duty ratio D of the signal is controlled. In contrast to the control of the duty ratio D, the slip control pressure actually supplied to the front chamber 26b of the lock-up clutch 26 does not immediately change. A response delay occurs when the clutch 26 shifts to the predetermined slip state.

However, as described above, the control unit 100 controls the duty ratio D so as to increase the slip amount in the first half of the shifting operation from the start of the inertia phase to a predetermined time, and therefore, the control unit 100 is shown in FIG. As shown by g, the control pressure rises relatively quickly, and as a result, the slip of the lock-up clutch 26 is promoted,
The state immediately shifts to the predetermined slip state.

Then, the duty ratio D is switched so that the slip amount becomes small at a predetermined time during the shift operation, and the duty ratio D is controlled so as to gradually return from this state to the lock-up state in the later stage of the shift operation. Therefore, after shifting to the predetermined slip state in the first half of the shifting operation as described above, in the second half of the shifting operation, the engine speed and the turbine speed decrease while maintaining an appropriate slip state. Then, as indicated by the symbol ク, the engine speed smoothly matches the turbine speed Nt1 after the turbine speed has decreased to the speed Nt1 after the shift is completed, that is, after the shift operation is completed.

As described above, while absorbing torsional vibration at the end of the shift, especially in the case of an upshift during acceleration, a situation in which the slip amount suddenly increases at the end of the shift and the engine speed rises. It is surely prevented.

[0060]

As described above, according to the present invention, a predetermined upshift is performed in a lock-up state in which a lock-up clutch that directly connects an input member and an output member of a torque converter provided in an automatic transmission is completely engaged. Is performed, when the lock-up clutch is controlled to be in the slip state, the engagement force of the clutch is controlled to be relatively small in the first half of the shifting operation and to be larger in the second half of the shifting operation. In the first half of the shifting operation, the slip of the lock-up clutch is promoted, and the state immediately shifts to the predetermined slip state.

Therefore, due to the response delay of the operating pressure,
It is possible to prevent the engine speed from rising at the end of the shift operation, such as when the gearshift operation is almost completely engaged in the first half of the shift operation and suddenly starts to slip in the second half of the shift operation. As a result, the shift is performed satisfactorily, and the shift feeling given to the occupant is improved.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing a configuration of an automatic transmission according to an embodiment of the present invention.

FIG. 2 is a lock-up clutch and a hydraulic circuit diagram for controlling the lock-up clutch.

FIG. 3 is a control system diagram of a lock-up clutch.

FIG. 4 is a map showing a control area of a lock-up clutch.

FIG. 5 is a flowchart illustrating a control operation of a lock-up clutch during upshifting.

FIG. 6 is a time chart showing changes in respective values under the control of FIG. 5;

FIG. 7 is a characteristic diagram of first and second duty ratios used in the control of FIG. 5;

FIG. 8 is a characteristic diagram of a predetermined rotation speed.

FIG. 9 is a time chart showing a conventional problem.

DESCRIPTION OF SYMBOLS 10 Automatic transmission 20 Torque converter 22 Input member (pump) 23 Output seat (turbine) 26 Lock-up clutch 84 Fastening force adjusting means (duty solenoid valve) 100 Lock-up control means, shift control means (Control) unit)

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kenji Sawa 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd.

Claims (7)

[Claims] 1. A torque converter is selectively controlled to one of a lock-up state in which an input member and an output member of a torque converter are completely engaged, a converter state in which the input member is completely released, and a slip state in which both members are relatively rotatably fastened. Lock-up clutch, engagement force adjusting means for adjusting the engagement force of the clutch, traveling state detecting means for detecting a traveling state of the vehicle including a value relating to a slip amount between the two members, and traveling state detecting means A lock which controls the state of the lock-up clutch in accordance with the traveling state detected in step (a) and controls the engagement force adjusting means so as to shift the clutch into a slip state during a predetermined upshift performed in the lock-up state. A lock-up clutch engagement force control device for an automatic transmission, the lock-up control device comprising: When the lock-up clutch is controlled from the lock-up state to the slip state at the time of the predetermined upshift, the clutch control means is configured to make the engagement force of the clutch greater in the latter half of the shifting operation than in the first half. An engagement force control device for a lock-up clutch, wherein the engagement force control unit is controlled. 2. The torque converter is selectively controlled to one of a lockup state in which an input member and an output member of a torque converter are completely engaged, a converter state in which the input member is completely released, and a slip state in which both members are relatively rotatably fastened. Lock-up clutch, engagement force adjusting means for adjusting the engagement force of the clutch, traveling state detecting means for detecting a traveling state of the vehicle including a value relating to a slip amount between the two members, and traveling state detecting means A lock which controls the state of the lock-up clutch in accordance with the traveling state detected in step (a) and controls the engagement force adjusting means so as to shift the clutch into a slip state during a predetermined upshift performed in the lock-up state. And a control device for controlling the engagement force of the lock-up clutch in the automatic transmission provided with the engagement control device. The means adjusts the engagement force of the lock-up clutch based on the value of the control signal from the lock-up control means, and the lock-up control means shifts the lock-up clutch from the lock-up state to the slip state during the predetermined upshift. When controlling
An engagement force control device for a lock-up clutch, wherein a value of a control signal output to the engagement force adjusting means is controlled so that the engagement force of the clutch is greater in the latter half of the shifting operation than in the first half. 3. A vehicle speed detecting means for detecting a value relating to a vehicle speed, an engine load detecting means for detecting a value relating to an engine load, a shift characteristic preset according to a value relating to a vehicle speed and an engine load, and both of the detecting means. Shift control means for controlling the gear position based on the detected values relating to the vehicle speed and the engine load, a lockup state in which the input member and the output member of the torque converter are completely engaged, and a converter state in which the input member and the output member are completely released. A lock-up clutch selectively controlled to one of slip states in which the clutch is relatively rotatable, a fastening force adjusting means for adjusting the fastening force of the clutch, and a lock-up clutch set in advance according to values relating to vehicle speed and engine load. Based on the lock-up characteristics and the values relating to the vehicle speed and the engine load detected by the two detection means. Lock-up control means for controlling the state of the clutch, and controlling the engagement force adjusting means so as to bring the lock-up clutch into a slip state when a predetermined upshift is performed by the shift control means in the lock-up state. Wherein the lock-up control means controls the lock-up clutch from a lock-up state to a slip state during the predetermined upshift, An engagement force control device for a lock-up clutch, wherein the engagement force adjusting means is controlled so that the engagement force of the clutch is greater in the latter half of the shifting operation than in the first half. 4. When the lock-up control means controls the lock-up clutch from a lock-up state to a slip state at the time of a predetermined up-shift, the engagement force of the clutch is larger in the latter half of the shift operation than in the first half. Control to output to the fastening force adjusting means or the fastening force adjusting means so that the latter fastening force of the shifting operation is set to an intermediate value between the earlier fastening force and the fastening force in the lock-up state. The engagement force control device for a lock-up clutch according to any one of claims 1 to 3, wherein the value of the signal is controlled. 5. The lock-up control means, when controlling the lock-up clutch from a lock-up state to a slip state during a predetermined up-shift, has made the slip amount between the input and output members of the torque converter equal to or more than a predetermined value. After that, the value of the engagement force adjusting means or a control signal output to the engagement force adjusting means is controlled so that the engagement force of the lock-up clutch becomes larger than before. The engagement force control device for a lock-up clutch according to any one of the above. 6. The lock-up control means, when controlling the lock-up clutch from a lock-up state to a slip state during a predetermined up-shift, changes the rotational speed of the output member of the torque converter from the rotational speed after the shift is completed by a predetermined rotational speed. After the number of revolutions has decreased to a high value, the value of the control signal output to the engagement force adjusting means or the engagement force adjustment means is controlled so that the engagement force of the lock-up clutch becomes larger than before. The engagement force control device for a lock-up clutch according to any one of claims 1 to 4. 7. The slip-up amount between the input and output members of the torque converter when the lock-up control means controls the lock-up clutch from the lock-up state to the slip state at the time of the predetermined up-shift speed has become greater than or equal to a predetermined value. After the earlier of the time point and the time point at which the rotational speed of the output member of the torque converter has decreased to a rotational speed higher than the rotational speed after the end of the shift by a predetermined rotational speed, the engagement force of the lock-up clutch is higher than before. The control of the engagement force of the lock-up clutch according to any one of claims 1 to 4, wherein the value of the engagement force adjustment means or a control signal output to the engagement force adjustment means is controlled so as to increase. apparatus.