JPH04316763A - Transmission torque capacity control device for lock up mechanism - Google Patents

Abstract

PURPOSE:To reduce transmission torque capacity of a lock up clutch for a given time starting from a time at which deceleration is switched to acceleration during lock up and to manage an input to a lock up damper to a constantly proper value, in a lock up mechanism to apply lock up control on a torque converter. CONSTITUTION:A lock up mechanism 22 comprising a lock up clutch 13, a lock up damper 14, and a damper spring 15 is operated in the direction of an arrow mark A when a converter actuating pressure is fed to an oil chamber 30 to separate a converter cover 12 away from the lock up clutch 13. When a converter actuating pressure is fed to an oil chamber 31, the lock up mechanism is operated in the direction of an arrow mark B to fasten the two members against each other. The converter actuating pressure is controlled by means of a command to a lock up solenoid 23 of an ECU 26 by means of input signals to sensors 27-29. Transmission torque capacity of the lock up clutch is reduced only for a given time A starting from a time at which deceleration is switched to acceleration during lock up operation, and an excessive input to the lock up damper 14 is suppressed to provide an increased life.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention performs lock-up control on a torque converter that transmits engine output to an automatic transmission, and can cope with excessive input by controlling the transmission torque capacity of the lock-up mechanism to an appropriate value. The present invention relates to a transmission torque capacity control device for a lockup mechanism.

0002

[Prior Art] As a conventional lock-up mechanism transmission torque capacity control device of this type, for example, Nissan Motor Co., Ltd.
“RE4RO1A Type Automatic Transmission Maintenance Manual (A261)” published in March 1986 by
CO7) I-13, 14, 28, 29, 3
Some are listed on pages 0, 74, and 75. In this conventional example, the torque converter receives power from the engine through hydraulic oil when the lock-up mechanism is released (when inactive) and through a lock-up clutch when the lock-up mechanism is engaged (when activated). Transmitted to automatic transmission. At this time, when the lockup clutch of the lockup mechanism is engaged, lockup control is performed to eliminate slippage of the converter and increase transmission efficiency.

0003

[Problems to be Solved by the Invention] However, in the above conventional example, when a sudden acceleration operation is performed during lock-up, the torque is transmitted through the engine → torque converter → lock-up clutch → lock-up damper → automatic transmission. The input to the lockup mechanism based on the engine output may become excessive, and especially when switching from deceleration to acceleration during lockup, the transmission torque applied to the lockup damper may suddenly change. There is a risk that the torque will increase to near the damper damage limit torque. Although it is possible to consider measures to increase the strength of the lock-up damper, there is a trade-off problem in that increasing the strength reduces the damping effect.

The present invention solves the above-mentioned problem by reducing the transmission torque capacity of the lockup mechanism to prevent excessive input from being transmitted to the lockup damper when an acceleration operation is performed from a deceleration state during lockup. The purpose is to

[0005]

[Means for Solving the Problems] For this purpose, the lockup mechanism transmission torque capacity control device of the present invention provides a lockup mechanism that performs lockup control on a torque converter as a fluid coupling that transmits engine output to an automatic transmission. In a vehicle system that controls a mechanism according to the driving state of the vehicle, a transmission torque capacity reducing means is provided for reducing the transmission torque capacity of the lockup mechanism when the lockup mechanism is switched from a deceleration state to an acceleration state. It is characterized by:

[0006]

[Operation] According to the present invention, while the torque converter functions as a fluid coupling to transmit engine output to the automatic transmission, the transmission torque capacity reducing means changes the driving state of the vehicle from the deceleration state to the acceleration state during lockup. When switched, the lockup mechanism is controlled to reduce the transmission torque capacity. As a result, the torque capacity transmitted from the lockup clutch to the lockup damper within the lockup mechanism is suppressed to a predetermined value or less corresponding to the damper damage limit torque, and the torque capacity transmitted to the lockup damper is appropriately controlled. can be kept at a value.

[0007]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the configuration of a first embodiment of a transmission torque capacity control device for a lockup mechanism according to the present invention, and numeral 10 in the figure indicates a torque converter. Torque converter 1
0 is a converter cover 12 located near an engine (not shown) and connected to the engine by a boss 11 for attaching a drive plate, and a back surface 12a of the converter cover.
A lockup clutch 13 located on the side, a lockup damper (torsion damper) 14 fitted to the lockup clutch 13, and a damper spring supported by the lockup damper 14 so as to be movable in the radial direction (vertical direction in the drawing). 15, a pump impeller 16 coupled to the converter cover 12, a stator 20 coupled to the input shaft 17 of the automatic transmission, and a one-way clutch 19 spline-fitted to the input shaft 17.
The turbine runner 18 as an output member is coupled to the turbine runner 18, and is configured similarly to the conventional example (RE4RO1A type) described above.

In this torque converter 10, the lockup clutch 13, lockup damper 14, and damper spring 15 constitute a lockup mechanism 22. This lockup mechanism 22 performs lockup control using converter operating pressure supplied from a hydraulic circuit 25 comprising a lockup solenoid 23 and a lockup control valve 24. This converter operating pressure is determined by the engine control computer (hereinafter referred to as ECU).
26 is controlled by a command signal to the lock-up solenoid 23, which is determined as described in detail below based on input signals from a fully closed throttle switch 27, a vehicle speed sensor 28, and a throttle sensor 29.

The torque converter 10 receives power from the engine through hydraulic oil when the lockup is released (when inactive) and through the lockup clutch 13 when the lockup is engaged (when activated). input shaft 1
7. That is, when the lockup is released, the torque converter operating pressure supplied from the lockup control valve 24 of the hydraulic circuit 25 is supplied to the oil chamber 30 between the converter cover 12 and the lockup clutch 13, as shown by the leftward arrow A in the figure. Clutch facing 21 stuck to lock-up clutch 13 due to
is separated from the converter cover 12. At this time, the engine driving force is converted from converter cover 12 to pump impeller 1.
6→hydraulic oil→turbine runner 18, and the torque converter 10 becomes fluidly connected. On the other hand, when the lock-up is engaged, the lock-up control valve 24
The operating pressure supply circuit is switched, and the torque converter operating pressure is supplied to the pump impeller 16, turbine runner 18, and stator 20 side, reaches the oil chamber 31 between the lockup clutch 13 and the lockup damper 14, and is then transferred to the converter cover 12. And the oil chamber 30 between the lockup clutch 13 is no longer supplied. At this time, the force acting on the lock-up clutch 13 from the left side (arrow B pointing to the right in the figure)
) is larger than the force acting from the right side, the clutch facing 21 of the lockup clutch 13 and the converter cover 12 are connected, and the power transmission efficiency is improved compared to when the lockup is released. In addition, the clutch facing 21 of the lock-up clutch 13 and the converter cover 1
Until the two are completely connected (hereinafter referred to as slip lock-up time), a predetermined relative rotation (
Feedback control is implemented to cause friction (slip), and power is transmitted in a frictionally engaged state (half-clutch state).

By the way, in this example, when performing the above-mentioned lock-up control, the durability of the lock-up mechanism at the time of excessive input due to acceleration operation from a deceleration state, etc. is taken into consideration.
The transmission torque capacity reduction control, which is the aim of the present invention, is also carried out. For this transmission torque capacity reduction control, the ECU 26 receives the O signal from the throttle fully closed switch 27.
N, a signal representing the OFF state, a signal representing the vehicle speed V from the vehicle speed sensor 28, and a throttle opening TH from the throttle sensor 29 (this can be considered to have a substantially linear relationship with the accelerator opening). ), and the ECU 26 executes the control program shown in FIG. 2 based on these input signals.

That is, first, in step 101 of the flowchart of FIG. 2, the above-mentioned signals are read from each of the sensors 27 to 29, and in step 102, it is determined whether or not a lock-up state has occurred. This determination can be made, for example, by searching a pre-stored map based on the vehicle speed V and throttle opening TH, and if the driving state of the vehicle at that time corresponds to the lock-up area in the map, the vehicle is in a lock-up state (lock-up state). ). If No in this determination, it is not in lockup and is not subject to the transmission torque capacity reduction control of this example, so step 103
The lock-up clutch 1 of the lock-up mechanism 22
A command is given to set the transmission torque capacity of No. 3 to zero. This command is issued by the ECU 26 to the lock-up solenoid 23 as described in the RE4RO1A maintenance manual.
By controlling the duty of the converter, the lock-up control valve 24 is switched so that the converter operating pressure acts as shown by arrow A in FIG.

[0012] In the determination of step 102, Yes
During the lockup, the state of the throttle fully closed switch is checked in the next step 104. Here, if the throttle fully closed switch is ON and the deceleration state is present, step 10
5, the flag FLAG is set and the timer T is reset (FLAG=1, T=0), and step 106
A command is issued to set the transmission torque capacity of the lock-up clutch 13 to a. This command, for example, causes the ECU 26 to control the duty of the lock-up solenoid 23 and switch the lock-up control valve 24 so that the converter operating pressure acts as shown by arrow B in FIG. Further, if it is determined in step 104 that the accelerating state is with the throttle fully closed switch OFF, the state of the flag FLAG is checked in step 107. If FLAG=1 here, this corresponds to the case of acceleration from a deceleration state, which is the object of the transmission torque capacity reduction control of this example, and therefore, in the next step 108, timer T is incremented (T=T+1). The timer T is incremented when the predetermined time A has elapsed and the determination in step 109 is Y.
The process is repeated until es (T>A), and a command is issued to set the transmission torque capacity to a during a predetermined time A at step 106. Then, when the predetermined time A has passed and the determination in step 109 becomes Yes, the flag F is determined in step 110.
After resetting LAG (FLAG = 0), a command is issued in step 111 to make the transmission torque capacity b larger than a (b>a).

The operation of the above control will be explained with reference to FIG. A lock-up mechanism 22 is used for a torque converter 10 as a fluid coupling that transmits engine output to an automatic transmission.
During lockup, where lockup control is being performed,
Control is Yes -1 in steps 101-102 in FIG.
04, and during deceleration, select Yes- in step 104.
105-106-101-102-104 Yes-
By repeating the loop 105-106, the transmission torque capacity of the lock-up clutch 13 is brought to a low value a as shown by the solid line in FIG. If an acceleration operation is performed at instant t1 while the deceleration state continues, the determination in step 104 is N.
o, so the control is Step 104 No-107 Yes-108-109 No-106-101-1
The loop of No in steps 02-104 is repeated, and the transmission torque capacity is maintained at a until the predetermined time A has elapsed (in this loop, the ECU 26 functions as a transmission torque capacity reducing means). At instant t2, when a predetermined time A has elapsed from instant t1, the determination in step 109 is Yes, so flag F is set in step 110.
After resetting LAG, in step 111, the transmission torque capacity of the lock-up clutch is set to b, which is a higher value than a, as shown by the solid line in FIG. In the case of the conventional example described above, the transmitted torque capacity becomes b during lockup, regardless of acceleration or deceleration, as shown by the dotted line in FIG.

The above control results in a half-clutch state in which slippage occurs between the lock-up clutch 13 and the converter cover 12, so as shown by the solid line in FIG. 3, the conventional lock-up clutch shown by the dotted line in FIG. It is possible to cut the output that exceeds the damage limit of the lock-up damper. As a result, the input to the lockup damper can always be suppressed to an appropriate torque capacity below the damper damage limit torque, and the life of the lockup damper can be improved.

[0015]

As described above, the transmission torque capacity control device for the lockup mechanism of the present invention reduces the transmission torque capacity of the lockup mechanism to prevent excessive input from occurring when an acceleration operation is performed from the deceleration state during lockup. Since transmission to the up-damper is prevented, the torque capacity transmitted from the lock-up clutch to the lock-up damper within the lock-up mechanism is suppressed to a predetermined value or less corresponding to, for example, the damper damage limit torque, and the lock-up damper The torque capacity transmitted to the engine can be maintained at an appropriate value.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a first embodiment of a transmission torque capacity control device for a lockup mechanism according to the present invention.

FIG. 2 is a flowchart showing a control program for transmission torque reduction control by the engine control computer in the same example.

FIG. 3 is a diagram for explaining the operation of the same example.

[Explanation of symbols]

10 Torque converter 12 Converter cover 13 Lockup clutch 14 Lockup damper 15 Damper spring 22 Lockup mechanism 23 Lockup solenoid 24 Lockup control valve 25 Hydraulic circuit 26 Engine control computer (ECU) 27
Throttle fully closed switch 28 Vehicle speed sensor 29 Throttle sensor

Claims (1)

[Claims] Claim 1: A vehicle system that controls a lock-up mechanism that performs lock-up control on a torque converter as a fluid coupling that transmits engine output to an automatic transmission according to the driving state of the vehicle, wherein the lock-up deceleration state is controlled. A transmission torque capacity control device for a lockup mechanism, comprising a transmission torque capacity reducing means for reducing the transmission torque capacity of the lockup mechanism when the lockup mechanism is switched from an acceleration state to an acceleration state.