JP3288459B2 - 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 an apparatus for controlling a coupling force of a fluid coupling of an automatic transmission, and
During deceleration or downhill traveling, the locking force of the lock-up mechanism is adjusted under predetermined operating conditions by the deceleration slip control that locks the lock-up mechanism in a slip state, and the member to be locked of the lock-up mechanism is relatively rotatably fastened. The present invention relates to an apparatus for controlling a fastening force of a fluid coupling to be operated.

[0002]

2. Description of the Related Art A multi-stage automatic transmission for a vehicle having a transmission gear mechanism has been widely put to practical use. This type of automatic transmission generally includes various friction engagement elements such as a clutch or a brake for controlling the operation of the transmission gear mechanism, and the friction engagement element selectively switches a power transmission path of the transmission gear mechanism to automatically shift the power transmission path. The speed ratio of the machine is set to a desired speed ratio. The automatic transmission determines a predetermined shift speed based on a predetermined shift determination map based on a range position of the select lever, a vehicle speed, a throttle opening, and the like, and determines a power transmission path of a transmission gear mechanism corresponding to the determined shift speed. A shift control device is provided for controlling the operation of the frictional engagement element via a hydraulic control circuit to form. The range position of the manually operated select lever is detected by the output signal of the inhibitor switch.

[0003] Such an automatic transmission is provided with a torque converter constituted by a fluid coupling. The torque converter transmits the power of the engine to the transmission gear mechanism via the fluid, and enables the vehicle to run smoothly. To On the other hand, the torque converter causes energy loss due to the relative rotation between the pump and the turbine. In order to reduce such energy loss, a lock-up mechanism capable of mechanically connecting the pump and the turbine is provided in the torque converter. The lock-up mechanism generally includes a hydraulically operated damper piston spline-fitted to a turbine hub and a hydraulic circuit for operating the damper piston. The lockup mechanism mechanically and mechanically connects the turbine shaft and the torque converter cover with the damper piston. Fasten integrally.

There is known a torque converter having a lock-up mechanism of this type, which includes a fastening force control device for variably controlling the fastening force of the lock-up mechanism (Japanese Patent Publication No. 63-13060). The force control device controls the operating oil pressure of the damper piston and adjusts the pressure applied between the damper piston and the torque converter cover during a predetermined operation state, for example, during operation under engine braking such as deceleration or downhill traveling. Thereby, the damper piston and the torque converter are fastened relatively rotatably, that is, fastened in a slip state.

A vehicle engine is generally controlled by an engine control unit that controls the fuel injection timing, fuel injection amount, ignition timing, and boost pressure of the engine. The engine control unit performs a so-called fuel cut in which the fuel injection of the fuel injection valve is stopped in a predetermined operation region of the engine. To prevent overheating and improve fuel efficiency.

[0006]

However, in the conventional automatic transmission, the engine braking action cannot be adjusted by the driver's intention, and the engine braking action is automatically determined by the operating conditions. It completely depends on the cut control and the deceleration slip control of the lock-up mechanism, and the driver cannot intentionally and positively increase the engine braking effect by manual operation or suppress the engine braking effect.

In a transmission gear mechanism of an automatic transmission, generally, the third speed in the D range and the third speed in the S range are determined by a common shift determination map, and as a result, substantially the same shift mode is set. In the automatic transmission equipped with the above-described fluid coupling engagement force control device, when the vehicle is decelerated in the D range and the third speed or travels downhill, the so-called engine brake is excessively effective.

Further, when the driver switches the automatic transmission to the S range while the vehicle is traveling in the D range and the fourth speed, the speed change gear mechanism shifts down to the third speed and the gear ratio of the speed change gear mechanism is reduced. Increase. As a result, in combination with the slipping action of the lock-up mechanism, the engine braking action is promoted relatively sharply, and excessively large engine braking is applied transiently against the driver's will. You can feel.

[0009] The present invention has been made in view of the above points, and the object thereof is to provide a driver's will.
An object of the present invention is to provide a fluid coupling fastening force control device capable of selectively adjusting an engine braking effect. It is a second object of the present invention to prevent an excessive engine braking effect that may occur when decelerating in a predetermined shift mode, for example, in the D range, third speed, or when traveling downhill.

[0010] The present invention further suppresses excessive engine braking action that may occur transiently when the range is switched from the D range to the S range, and prevents the driver from feeling excessive deceleration when switching the range. As a third object. It is a further object of the present invention to provide a fluid coupling fastening force control device that can prevent excessive application of an engine brake while improving fuel economy by fuel cut.

[0011]

According to the present invention, there is provided a fastening force control device for controlling a fastening force of a lock-up mechanism in a fluid coupling of an automatic transmission. By a deceleration slip control for fastening the lock-up mechanism in a slip state, a fastening force of the lock-up mechanism is adjusted under predetermined operating conditions, and a fluid coupling for fastening a member to be fastened of the lock-up mechanism so as to be relatively rotatable. A deceleration slip control means for controlling a fastening force of the lock-up mechanism at the time of deceleration or downhill running; a range detection means for detecting a range position of the shift control device of the automatic transmission; Fastening force changing means for changing the fastening force of the lock-up mechanism under the deceleration slip control based on the position. Based on the position and gear position, and determines the slip control determination means the execution of the deceleration slip control,
Slip control execution means for executing deceleration slip control based on the determination result of the slip control determination means, wherein the slip control determination means performs the deceleration slip control as the highest speed stage shifts to a lower set range position. Is provided with a determination criterion in which the lower limit of the operating range in which is performed is set to a lower speed band.

According to the present invention having such a configuration,
For example, the automatic transmission executes the deceleration slip control substantially only at the fourth speed in the D range, executes the deceleration slip control only at the third speed in the S range, and further executes the deceleration slip control in the L range.
The deceleration slip control can be executed at the second speed. This makes it possible to suppress the excessive engine braking effect generally occurring in the D range, the third speed, and the like in the vehicle equipped with the conventional automatic transmission by the shift operation of the driver.

[0013]

[0014]

In a further preferred aspect of the present invention, the engine to which the automatic transmission is connected executes a fuel cut during deceleration. As a result, it is possible to reduce the engine braking effect and prevent the driver from feeling excessive deceleration while improving fuel efficiency by executing fuel cut of the engine. Another aspect of the present invention is a fastening force control device for controlling a fastening force of a lock-up mechanism in a fluid coupling of an automatic transmission, wherein the lock-up mechanism is engaged in a slip state during deceleration or traveling downhill. By the deceleration slip control, the fastening force of the lock-up mechanism is adjusted under predetermined operating conditions, and the fastening force control device of the fluid coupling for fastening the member to be fastened of the lock-up mechanism so as to be relatively rotatable. Deceleration slip control means for controlling the engagement force of the lock-up mechanism during downhill traveling, range change detection means for detecting range position change of the shift control device, and when a range position change operation for increasing the gear ratio is detected And a fastening force changing means for at least transiently reducing the fastening force of the lock-up mechanism. Provides a force control device.

Generally, when the vehicle is traveling at a relatively high speed, a range switching operation is performed, for example, a shift operation from the D range to the S range is performed. With the increase of the ratio and the execution of the deceleration slip control, a situation may occur in which the engine braking action suddenly occurs. However, according to the above-described configuration, it is possible to prevent such an abrupt engine braking action from occurring, and to avoid an excessive feeling of deceleration that the driver may transiently feel.

The control of the fastening force of the lock-up mechanism is performed, for example, by linearly and variably controlling the operating oil pressure of a hydraulic circuit for operating the lock-up mechanism, or by variably controlling the operating oil pressure stepwise. Can be implemented relatively easily.

[0018]

1 is a schematic configuration diagram of an automatic transmission controlled by a fastening force control device according to an embodiment of the present invention, and FIG. 2 is a schematic vertical sectional view showing a structure of a torque converter. In FIG. 1, an automatic transmission 1 includes a torque converter 2 configured as a fluid coupling, a transmission gear mechanism 3 driven by an output of the torque converter 2, a forward clutch 4 for switching a power transmission circuit of the transmission gear mechanism 3, a coast, The clutch 5 includes a clutch 5, a 3-4 clutch 6, a reverse clutch 7, a 2-4 brake 8, a friction engagement element including a low reverse brake 9, and first and second one-way clutches 10 and 11. By engaging or disengaging or disengaging or disengaging the coupling element and the one-way clutches 10 and 11, each driving range of the D range, S range, L range and R range, and 1 to 4 in the D range. Speed, the first to third speeds in the S range, and the first and second speeds in the L range, respectively. That.

The torque converter 2 is disposed so as to face a case 20 connected to an engine output shaft 15 of a multi-cylinder engine (not shown), a pump 21 fixed in the case 20, and the pump 21. A turbine 22 driven by a pump 21 via hydraulic oil, a stator 24 disposed between the turbine 22 and the pump 21 and supported by a casing 16 of the transmission via a one-way clutch 23, A lock-up clutch 25 is provided between the turbine 22 and the engine 22. The lock-up clutch 25 can selectively connect the engine output shaft 15 and the turbine 22.

The torque converter 2 transmits the rotation of the case 20 to the turbine 22 via the fluid, and the rotation of the turbine 22 is transmitted to the transmission gear mechanism 3 via the turbine shaft 26. A pump shaft 17 that passes through the inside of the turbine shaft 26 is connected to the engine output shaft 15, and the pump shaft 17 drives an oil pump 18 disposed at a rear end of the automatic transmission 1.

The torque converter 2 also mechanically connects the case 20 and the turbine shaft 26 by engaging the lock-up clutch 25, so that the rotation of the engine output shaft 15 is controlled by the turbine through the lock-up clutch 25. It can be transmitted directly to the shaft 26. FIG.
As shown in FIG. 5, the lock-up clutch 25 includes a damper piston 25a that is hydraulically operated and a torsion damper 25b that absorbs fluctuations in engine torque during lock-up. An operating hydraulic chamber 2F formed between the damper piston 25a and the case 20 communicates with the oil passage 30, and an operating hydraulic chamber 2R formed between the damper piston 25a and the turbine 22 communicates with the oil passage 31. are doing. Oilway 3
Reference numerals 0 and 31 are connected to a hydraulic circuit (not shown) for a working fluid, and the hydraulic circuit includes a lock-up control valve (not shown) for controlling engagement of the lock-up clutch 25. When an AT control unit (not shown) of the automatic transmission determines lock-up under predetermined operating conditions, the lock-up control valve is shifted to supply hydraulic oil to the hydraulic pressure chamber 2R via the oil passage 31 and The operating oil in the operating hydraulic chamber 2F is discharged through the oil passage 30. As a result, the pressure in the working hydraulic chamber 2F decreases, and the damper piston 25a frictionally engages with the case 20. Thus, the case 20 and the turbine shaft 26 are mechanically and integrally connected to each other through the lock-up clutch 25. You.

Further, the lock-up control valve is controlled by the AT control unit to operate the hydraulic pressure chamber 2R.
Can be variably controlled, whereby the engagement force of the lock-up clutch 25, that is,
A so-called deceleration slip control for adjusting the frictional engagement force between the damper piston 25a and the case 20 to fasten the damper piston 25a and the case 20 in a slip state is performed. The torque converter 2 under the deceleration slip control is transmitted from the case 20 through the lock-up clutch 25 to the turbine shaft 2.
The frictional engagement force between the damper piston 25a and the case 20 is adjusted to variably control the torque transmitted to the case 6.

As shown in FIG. 1, the transmission gear mechanism 3 is composed of a Ravigneaux type planetary gear device, and has a small diameter small sun gear 30 loosely fitted on a turbine shaft 26.
And a large-diameter large sun gear 31 which is disposed behind the small sun gear 30 and is loosely fitted on the turbine shaft 26.
A plurality of short pinion gears 32 meshing with the small sun gear 30; a long pinion gear 33 having a first half meshing with the plurality of short pinion gears 32 and a second half meshing with the large sun gear 31; a plurality of short pinion gears 32; The long pinion gear 33 includes a carrier 34 that rotatably supports the carrier 33 and a ring gear 35 that meshes with the front half of the long pinion gear 33.

The forward clutch 4 and the first one-way clutch 10 are arranged in series in a power transmission path between the turbine shaft 26 and the small sun gear 30, and are arranged in parallel with the forward clutch 4 and the first one-way clutch 10. , A coast clutch 5 is disposed. Further, the 3-4 clutch 6 is connected to the turbine shaft 2.
The reverse clutch 7 is provided on a power transmission path between the turbine shaft 26 and the large sun gear 31. Further, a band brake for fixing the large sun gear 31, that is, a 2-4 brake 8 is provided in a power transmission path between the large sun gear 31 and the reverse clutch 7, and a second brake that supports the reaction force of the carrier 34. One-way clutch 1
1 and a low reverse brake 9 for fixing the carrier 34
Are arranged in parallel between the carrier 34 and the casing 16 of the transmission. The ring gear 35 is the output gear 1
9 is connected to the output gear 19.
And transmitted to left and right wheels (not shown) via a differential device or the like (not shown).

Forward clutch 4, Coast clutch 5, 3-4 clutch 6, Reverse clutch 7, 2-4
A desired shift mode is obtained by engaging or disengaging the friction engagement element including the brake 8 and the low reverse brake 9 and the one-way clutches 10 and 11 as shown in the following table, or operating or not operating. .

[0026]

[Table 1] FIG. 3 is a schematic block diagram of a vehicle control device including the fastening force control device according to the present embodiment. The vehicle control device includes an AT control unit E1 for controlling the hydraulic circuit of the automatic transmission and an engine control unit E2 for controlling the operation of the multi-cylinder engine, and the AT control unit E1 according to the present embodiment. A fastening force control device is provided. The AT control unit E1 and the engine control unit E2 include a throttle opening sensor 100 for detecting a throttle opening, a vehicle speed sensor 102 for detecting a vehicle speed, a pressure sensor 104 for detecting a negative pressure of an intake manifold of the engine, and an engine output shaft 15.
The respective detection results of the output shaft rotation speed sensor 106 for detecting the rotation speed of the turbine shaft 26 and the turbine shaft rotation speed sensor 108 for detecting the rotation speed of the turbine shaft 26 are input. Further, an inhibitor switch 110 of a select lever is connected to the AT control unit E1.

The AT control unit E1 determines a required shift mode based on the range position of the select lever, the throttle opening and the vehicle speed detected by the throttle opening sensor 100 and the vehicle speed sensor 102, and determines the friction engagement element. By engaging or releasing, the power transmission path of the transmission gear mechanism is set to a required transmission mode. Further, the AT control unit E1 includes deceleration slip control means. The deceleration slip control means is based on the intake manifold negative pressure detected by the pressure sensor 104 and the engine speed detected by the output shaft speed sensor 106. When it is determined that the engine is operating in a predetermined operating region where the intake manifold negative pressure is relatively large and the engine speed is relatively low, the deceleration slip control is executed and the turbine shaft speed sensor 108 The engagement force of the lock-up clutch 25, that is, the force between the damper piston 25a and the case 20 is adjusted so that the difference between the rotation speed of the turbine shaft 26 detected by the above and the engine rotation speed matches the desired set rotation speed difference. The frictional engagement force is adjusted via a hydraulic circuit.

The engine control unit E2 controls the fuel injection timing of the engine 200, the fuel injection amount, the ignition timing, the boost pressure, etc., based on the detection results of the throttle opening sensor 100, the vehicle speed sensor 102, and the like. The engine control unit E2 also includes a fuel cut control unit that executes a fuel cut under predetermined operating conditions.
The fuel injection from the fuel injection valve of the engine is stopped to the fuel cut limit rotation speed, and the engine is operated at a high engine rotation speed and a low intake air amount during deceleration of the vehicle or during engine braking action during downhill running. To improve fuel efficiency while preventing overheating under conditions.

FIG. 4 is a flowchart schematically showing a subroutine for controlling the engagement force of the lock-up mechanism in the AT control unit E1. The AT control unit E1 detects the current manual setting range of the select lever by the inhibitor switch 110, and when the setting range is located in the S range, a first slip control determination map (hereinafter, referred to as a first determination map). Is selected (S2, S4), and when the set range is located in the D range, a second slip control determination map (hereinafter, referred to as a second determination map) is selected (S1, S4).
3).

The first determination map is set so as to determine the execution of the deceleration slip control in the S range in a predetermined operation range based on the throttle opening and the vehicle speed. The predetermined operating range in the first determination map is within a range of the third speed operating range in the shift determination map of the AT control unit E1, and the deceleration operating range in the third speed operating range, for example, the throttle opening is a predetermined value. The following operating ranges are set.

The second determination map is set so as to determine the execution of the deceleration slip control in the D range in a predetermined operation range based on the throttle opening and the vehicle speed. The predetermined operating range set in the second determination map is AT
The first unit includes a first operating region corresponding to the third speed in the shift determination map of the control unit E1, and a second operating region corresponding to the fourth speed operating region in the shift determination map.
The second operating range is set to a decelerating operating range in the third and fourth speed operating ranges, for example, an operating range in which the throttle opening is equal to or less than a predetermined value.

In the S range, the AT control unit E1 makes a slip control determination using the first determination map based on the throttle opening and the vehicle speed (S4, S4).
6). When the driver releases the accelerator or the vehicle is traveling on a downhill and the vehicle is traveling in a driving state in which the deceleration slip control is to be executed, that is, the current throttle opening and the vehicle speed are the first. When the vehicle is in the predetermined operation range set in the determination map, the AT control unit E1 executes the deceleration slip control (S8). The AT control unit E1 further releases the deceleration slip control when the vehicle accelerates or gets out of a downhill and shifts to an operation state in which the deceleration slip control should be released (S10).

The AT control unit E1 also operates in the D range based on the throttle opening and the vehicle speed.
Slip control determination is performed using the determination map (S3, S3
5) When the vehicle is running in an operating state in which deceleration slip control should be executed, that is, the current throttle opening and vehicle speed are in the first operating range or the second operating range set in the second determination map. At this time, deceleration slip control is executed (S7),
On the other hand, when the vehicle shifts to the driving state in which the deceleration slip should be released, the deceleration slip control is released (S9).

The deceleration slip control means of the AT control unit E1 controls the intake manifold negative pressure, the engine speed and the engine speed when the operating state of the vehicle corresponds to a predetermined operating range of the first determination map or a second operating range of the second determination map. Based on the speed, a desired target speed difference between the speed of the turbine shaft 26 and the engine speed is set. The slip control means further sets an operating oil pressure to achieve the engagement force of the lock-up clutch 25 corresponding to the target rotational speed difference, and reduces the oil pressure supplied to the operating oil pressure chamber 2R by the lock-up control valve. Adjust to the set hydraulic pressure. Thus, the deceleration slip control in the S range 3rd speed and the D range 4th speed allows the damper piston 25a
The frictional engagement force between the and the case 20 is adjusted.

On the other hand, the deceleration slip control means of the AT control unit E1 controls the turbine shaft 26 when the operating state of the vehicle corresponds to the first operating range of the second determination map.
The desired target rotational speed difference between the rotational speed of the engine and the engine rotational speed is set in the same manner, but the hydraulic pressure is set to a hydraulic pressure lower than the hydraulic pressure corresponding to the target rotational speed difference, and the lock-up control valve is used. , Damper piston 25
a and the case 20 is adjusted to a relatively low frictional engagement force. Thus, in the deceleration slip control in the D range and the third speed, the damper piston 25a and the case 20
Is reduced.

As a modification, when the driving state of the vehicle corresponds to the first operating range of the second determination map, the damper piston 2
The AT control unit E1 may be configured so as to completely release the case 5a and the case 20. in this way,
In the above embodiment, the AT control unit E1 determines the frictional engagement force between the damper piston 25a constituting the lock-up mechanism and the case 20 when decelerating or traveling downhill.
Variable control by deceleration slip control means,
The range position of the select lever is detected, and the friction engagement force between the damper piston 25a and the case 20 is reduced by the deceleration slip control in the D range / third speed, or the damper piston 25a and the case 20 are released. Therefore, the driver can intentionally adjust the engine braking action by changing the engagement force of the lock-up mechanism under the deceleration slip control by the selective range switching operation (D range-S range) of the select lever. In addition, in the deceleration slip control of the D range and the third speed, the damper piston 25a and the case 2
Since the frictional engagement force with zero is reduced, the excessive engine braking effect generally occurring in the D range and third speed in the vehicle equipped with the conventional automatic transmission can be reduced.

Further, the AT control unit E1 is
The configuration may be such that the deceleration slip control is not executed in the D range and third speed. In this case, the AT control unit E1 executes the deceleration slip control at the fourth speed in the D range, and executes the deceleration slip control at the third speed in the S range. That is, as the range shifts from the D range to the S range,
The lower limit of the operating range in which the deceleration slip control is to be performed is set on the low speed side. As a result, an excessive engine braking effect that can occur in the third range of the D range can be eliminated by the driver's shift operation.

Further, in the above-described embodiment, the engine control unit E2 is configured to perform the fuel cut control during the deceleration of the vehicle or during the engine braking operation during the downhill running, so that the engine fuel cut is controlled. It is possible to suppress the occurrence of an excessive engine braking effect while improving the fuel efficiency by the control. FIG. 5 is a flowchart schematically showing another embodiment of the subroutine for controlling the engagement force of the lock-up mechanism.

Similarly to the above-described embodiment, the AT control unit E1 detects the current manual setting range of the shift lever by the inhibitor switch 110 and determines whether the setting range is located in the D range or the S range. Is determined (S11, S12). When the shift lever is in the D range, the AT control unit E1 executes the second routine described above substantially in accordance with the same routine as that of the above-described embodiment (see S3, S5, S7, S9, and S9).
The deceleration slip control is determined based on the determination map (S21 to S24). When the shift lever is in the S range, substantially the same routine as in the above-described embodiment (FIGS. 4, S4, 6, 8, and 10), the deceleration slip control is determined based on the first determination map (S1).
2 to S16, S18). That is, D range, 4th gear or 3rd gear
When the vehicle decelerates in the third speed and the third speed, or when the vehicle is traveling on a downhill, the deceleration slip control is executed, while the vehicle accelerates or the vehicle exits the downhill. Then, the deceleration slip control is released. Also, D
In the deceleration slip control in the range third speed, the frictional engagement force between the damper piston 25a and the case 20 is reduced.

Further, in this example, when the range is switched to the S range by operating the select lever while the vehicle is operating in the D range, 4th speed, the AT control unit E1
Temporarily prohibits the deceleration slip control in order to avoid the sudden occurrence of the engine braking action (S15,
S17). That is, when the deceleration slip control has been executed in the D range before the predetermined time t (S15), even if the operation state in which the deceleration slip control should be executed is determined by the first determination map, the execution of the deceleration slip control is performed. Is prohibited (S17).

As described above, in the fastening force control device of this embodiment, the AT control unit E1 uses the lock-up control valve to reduce the frictional engagement force between the damper piston 25a and the case 20 constituting the lock-up mechanism. Alternatively, when the range position is switched from the D range to the S range by the shift operation of the select lever while performing variable control during downhill traveling, a predetermined time t
During the period, execution of the deceleration slip control is prohibited. Accordingly, when the driver performs a shift operation from the D range to the S range and the shift speed is shifted down from the fourth speed to the third speed, the execution of the deceleration slip control is temporarily prohibited, so that the shift down is performed. An abrupt occurrence of the engine braking effect accompanying the increase in the gear ratio and the execution of the deceleration slip control is prevented. Thus, according to the fastening force control device of the present embodiment, it is possible to prevent the engine braking action from being excessively effective due to the shift operation, and to prevent the driver from feeling excessive deceleration during the shift operation.

[0042]

According to the first aspect of the present invention, the engagement control device for the fluid coupling is provided with a lock under the deceleration slip control by the shift operation of the select lever, that is, the selective range switching. Change the fastening force of the up mechanism,
The engine braking effect by the power transmission between the transmission gear mechanism and the engine can be adjusted. Therefore, it is possible to provide a fluid coupling fastening force control device capable of selectively adjusting the engine braking action according to the driver's will.

According to the second aspect of the present invention, the lower limit of the operation range in which the deceleration slip control is to be executed is further reduced as the highest speed shifts to the range position set lower. By setting the band to the range of, for example, the engagement force control device executes the deceleration slip control substantially only in the fourth speed in the D range, and executes the deceleration slip control only in the third speed in the S range. Can be configured. Therefore, by such a fastening force control device, it is possible to prevent an excessive engine braking effect that may occur when the vehicle is decelerated in the D range, third speed, or the like, or travels downhill.

According to the third aspect of the present invention, for example, in the D range and the third speed, the lock-up fastening force is released or set relatively low.
In the range-third speed, the lock-up fastening force is set to a relatively high value because the fastening force is applied or set relatively high.
It is possible to suppress an excessive engine braking action that can occur at a speed or the like.

According to the configuration of the present invention described in claim 4, a situation in which the engine braking action suddenly occurs due to a range switching operation, for example, a shift operation from the D range to the S range, is avoided. As a result, it is possible to prevent the occurrence of a sudden engine braking action that may occur at the time of the shift operation, and to avoid an excessive feeling of deceleration due to the excessive effect of the engine braking action.

According to the configuration of the present invention described in claim 5, it is possible to suppress the engine braking effect and prevent the driver from feeling excessive deceleration while improving fuel efficiency by cutting fuel.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an automatic transmission controlled by a fastening force control device according to an embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional view showing the structure of the torque converter shown in FIG.

FIG. 3 is a schematic block diagram illustrating a configuration of a fastening force control device according to the present invention.

FIG. 4 is a flowchart schematically showing a subroutine for controlling a fastening force of a lock-up mechanism in an AT control unit.

FIG. 5 is a flowchart schematically showing another embodiment of a subroutine for controlling a fastening force of a lock-up mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Automatic transmission 2 Torque converter 2F, 2R Working hydraulic chamber 3 Transmission gear mechanism 15 Engine output shaft 20 Case 22 Turbine 25 Lock-up clutch 25a Damper piston 25b Torsion damper 26 Turbine shaft 30, 31 Oil passage 100 Throttle opening sensor 102 Vehicle speed Sensor 104 Pressure sensor 106 Output shaft speed sensor 108 Turbine shaft speed sensor E1 AT control unit E2 Engine control unit

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-260464 (JP, A) JP-A-63-318361 (JP, A) JP-A-63-178662 (JP, U) JP-A-6-178662 30558 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 61/14

Claims (3)

(57) [Claims] 1. A fastening force control device for controlling a fastening force of a lock-up mechanism in a fluid coupling of an automatic transmission, wherein a deceleration slip control for engaging the lock-up mechanism in a slip state during deceleration or downhill traveling. Thus, the fastening force of the lock-up mechanism is adjusted under predetermined operating conditions, and the fastening force control device of the fluid coupling for relatively fastening the member to be fastened of the lock-up mechanism in a relatively rotatable manner. Deceleration slip control means for controlling the time of deceleration or downhill traveling, range detection means for detecting the range position of the shift control device of the automatic transmission,
A fastening force changing means for changing a fastening force of the lock-up mechanism under deceleration slip control based on the detected range position, wherein the fastening force changing means performs deceleration slip control based on the range position and the gear position. And a slip control executing means for executing a deceleration slip control based on a result of the determination by the slip control determining means. And a determination criterion in which the lower limit of the operating range in which the deceleration slip control is to be executed is set to a lower speed range as the vehicle shifts to the range position. 2. A deceleration slip control for controlling a fastening force of a lock-up mechanism in a fluid coupling of an automatic transmission, wherein the deceleration slip control engages the lock-up mechanism in a slip state during deceleration or traveling on a downhill. Thus, the fastening force of the lock-up mechanism is adjusted under predetermined operating conditions, and the fluid-coupling fastening force control device that fastens the member to be fastened to the lock-up mechanism so as to be relatively rotatable. Deceleration slip control means for controlling the engagement force of the lock-up mechanism, range change detection means for detecting a change in the range position of the shift control device, and at least a transient state when a range position change operation for increasing the gear ratio is detected. And a fastening force changing means for reducing the fastening force of the lock-up mechanism. . 3. The control device according to claim 1, wherein the fluid coupling is connected to an engine that performs fuel cut during deceleration or downhill traveling.