JPH02256962A - Control device of lockup clutch - Google Patents

Abstract

PURPOSE:To place a lockup clutch in a slip condition during a speed change by providing constitution in such a way as actuating a solenoid by duty ratio preset during the speed change. CONSTITUTION:In case of not during a speed change, present gear ratio G is obtained in a device next calculating a speed Nt of a turbine runner 14 from an output shaft speed No and the gear ratio G and next a difference R between an engine speed Ne and the speed Nt, that is, a slip amount of a torque converter 10. A lockup clutch 18 is feedback controlled by comparing the speed difference R with a target speed difference S and placed in a slip condition. On the contrary, in case of during the speed change, a time from its start is measured, and the control device, clearing an in-speed change flag, when the feedback inhibition time passes, and outputting fixed duty ratio preset in accordance with a throttle opening when the inhibition time not passes, controls to the predetermined duty ratio a solenoid 58 placing the clutch 18 in a slip condition of predetermined proportion.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a control device for a lock-up clutch.

(B) Prior Art A conventional lock-up clutch control device is disclosed in, for example, Japanese Patent Laid-Open No. 60-241570. The torque converter of the automatic transmission shown in this figure has a lock-up clutch, and this lock-up clutch is fully engaged in two or more gears. When shifting from a state in which the lock-up clutch of a predetermined gear is engaged to a state in which the lock-up clutch of another gear is engaged, the lock-up clutch is temporarily released. That is, the lock-up clutch is released a predetermined time after the shift command signal is output, and the lock-up clutch is re-engaged after a predetermined time.

The gear shift is completed while this lock-up clutch is released. This is intended to alleviate shock during gear shifting.

(c) Problems to be Solved by the Invention However, the conventional lock-up clutch control device as described above has a problem in that when the lock-up clutch is released during gear shifting, the fluid transmission state is established, so the engine rotational speed increases. There is a problem in that the engine feels like it is revving, and conversely, the engine rotational speed decreases when re-engaged, resulting in a shock. Furthermore, since the engine rotational speed increases, fuel consumption also increases, although only during gear shifting. In order to solve the above-mentioned problems, the lock-up clutch may be placed in a slipping state during gear shifting.

In addition to the above, it is also necessary to keep the lock-up clutch in a slipping state during gear shifting, for example, when the lock-up clutch is constantly controlled to slip. In order to control the lock-up clutch to a slipping state during gear shifting,
It is necessary to detect the rotational speed at the input end (engine rotational speed) and the rotational speed at the output side (turbine rotational speed) of the torque converter (see Japanese Patent Laid-Open No. 61-99763).
. (Although it is possible to calculate the turbine rotational speed from the output shaft rotational speed and the gear ratio when the gear is not in use during the gearshift, this is not possible because the gear ratio is unknown during the gearshift. ) However, in order to detect the rotational speed of the turbine runner, it is necessary to install a turbine rotational speed sensor adjacent to the turbine shaft or a member that rotates integrally with it. Placing a rotational speed sensor adjacent to the turbine shaft, which is located at the (It is very difficult to locate the turbine rotation speed sensor). Further, even if it is possible to arrange a turbine rotational speed sensor, the arrangement requires space and increases the cost. The present invention aims to solve these problems.

(d) Means for Solving the Problems The present invention solves the above problems by operating a solenoid at a preset duty ratio during gear shifting. That is, the lock-up clutch control device of the present invention includes an engine, a rotation speed sensor that detects the engine rotation speed, an output shaft rotation speed sensor that detects the rotation speed of the output shaft, and a gear ratio that is detected during non-shifting. a gear ratio detection means, a turbine rotation speed calculation means for calculating the rotation speed of the turbine runner based on a signal from the output shaft rotation speed sensor and a signal from the gear ratio detection means;
Activation of the solenoid when desired during non-shifting so that the difference between the engine rotation speed detected by the engine rotation speed sensor and the turbine rotation speed calculated by the turbine rotation speed calculation means becomes a preset setting value. a non-shifting slip control means for performing feedback control, and a non-shifting slip control means for stopping the feedback control for a predetermined period of time after a shift is commanded, and controlling at least a duty ratio signal set in advance corresponding to the throttle opening degree. and a gear shift slip control means for outputting an output to the solenoid.

(e) Operation During non-shifting, the rotational speed of the turbine runner is calculated from the gear ratio obtained by the gear ratio detection means and the output shaft rotational speed. Feedback control of the lock-up clutch is performed so that the difference between the actual engine rotation speed and the calculated rotation speed of the turbine runner becomes a predetermined state. This allows the lock-up clutch to be in a slipping state during non-shifting. On the other hand, during gear shifting, a preset duty ratio is output to the solenoid, and the lock-up clutch is placed in a slipping state. Therefore, an existing output shaft rotation speed sensor can be used, and there is no need to provide a dedicated turbine rotation speed sensor.

(F) Embodiment FIG. 2 shows an embodiment of the present invention. Torque converter 10
has a lock-up clutch 18 in addition to a pump impeller 12, a turbine runner 14, and a stator 16. An apply chamber 20 in which the pump impeller 12, turbine runner 14, etc. are arranged is formed on the right side of the lock-up clutch 18 in the figure, and a release chamber 22 is formed on the left side of the lock-up clutch 18 in the figure. An oil passage 24 is connected to the apply chamber 20, and the release chamber 22
An oil passage 26 is connected to.

Note that the lock-up clutch 18 is connected to the torque converter 1.
It has a facing 30 that contacts the friction surface of the cover 28 of 0. The state of oil pressure supply to the oil passages 24 and 26 is controlled by a lock-up control valve 32. Lockup control valve 32 includes a spool 34, a sleeve 36, a plug 38, and a spring 40. In addition, oil passages 42, 44, 46, 48, and 50 other than the above-mentioned oil passages 24 and 26
Both are connected as shown.

A constant pressure is supplied to the oil passage 42 from a torque converter relief valve 52. Incidentally, the torque converter relief valve 52 performs a pressure regulating function using the oil pressure of an oil passage 54 that is supplied with oil pressure from a pressure regulator valve (not shown). The oil passage 44 is connected to an oil cooler 56, and the oil exiting the oil cooler 56 is used for lubrication.

A constant pressure regulated by a pressure regulating valve (not shown) is supplied to the oil passage 50. Oil passage 50 and orifice 56
The branched oil passage 46 is connected to a lock-up solenoid 58. The lock-up solenoid 58 includes a plunger 62 that closes the opening 60 of the oil passage 46 in a de-energized state.
The energization state is controlled by the duty ratio by a signal from the control unit 64. That is, the lock-up solenoid 58 is repeatedly turned on and off at a predetermined period, and opens the opening 60 in accordance with the ratio of the on-time, thereby regulating the oil pressure in the oil passage 46 so as to be inversely proportional to the on-time. The control unit 64 includes an engine rotation speed sensor 66 and an output shaft rotation speed sensor (vehicle speed sensor) 68.
, and the throttle opening sensor 70 are input manually, and the control unit 64 controls the operation of the lock-up solenoid 58 as described later based on these signals.

Next, the operation of this embodiment will be explained.

First, control of the lock-up clutch 18 in its released state, closed state, and fully engaged state will be explained.

The released state of the lock-up clutch 18 is realized as follows. That is, the lock-up solenoid 58 has a duty ratio of 0, and the opening 60 is connected to the plunger 62.
completely shut down. Therefore, the same hydraulic pressure as in the oil passage 50 is generated in the oil passage 46, and stiffness acts on the left end of the spool 34 of the lock-up control valve 32. Therefore, the spool 34 is in the state shown in the figure, and the oil pressure in the oil passage 42 is applied to the release chamber 22 through the oil passage 26.
Furthermore, the hydraulic pressure of this release chamber 22 is supplied to the cover 2.
It flows into the apply chamber 20 side through the gap between the friction surface of No. 8 and the facing 30, then returns to the lock-up control valve 32 through the oil passage 24, and then through the oil passage 44.
is discharged to. That is, hydraulic pressure is supplied from the oil passage 26 to the release chamber 22, and then from the apply chamber 20 to the oil passage 24.
is discharged to. Therefore, the oil pressure in the release chamber 22 and the oil pressure in the apply chamber 20 are the same (note that, strictly speaking, the apply chamber 20 side is on the downstream side, so the apply chamber 20 side is slightly lower due to flow path loss). As a result, the lock-up clutch 18 becomes released.

That is, the torque converter 10 enters a torque converter state in which rotational force is transmitted only through fluid.

When controlling the lock-up clutch 18 from the above state to the slip state, the following operation is performed. That is,
When the duty ratio given to the lock-up solenoid 58 from the control unit 64 is gradually increased, oil is discharged from the opening 60 and the oil pressure in the oil passage 46 decreases in accordance with this duty ratio. Therefore, the hydraulic pressure acting on the left end of the spool 34 of the lock-up control pulp 32 decreases, and the spool 34 and plug 38 move leftward in the figure. When the spool 34 and the plug 38 move leftward by a predetermined amount, the oil passage 26 becomes slightly in communication with the drain boat 72, and at the same time, the oil passage 42 becomes in communication with the oil passage 24. The oil pressure of the oil passage 26 is the same as that of the oil passage 4.
8 to the right end of the plug 38, the lock-up control valve 32 is in a pressure regulating state, and the oil pressure in the oil passage 26 is fed back to the right end of the plug 38 through the oil passage 46.
The pressure is regulated in accordance with the oil pressure acting on the left end of 4. That is, in this state, hydraulic pressure is supplied to the torque converter 10 from the oil passage 24 to the apply chamber 20, and the hydraulic pressure in the apply chamber 2o is supplied to the lock-up clutch 18 and the cover 2.
8, enters the release chamber 22, and is discharged from the oil passage 26. The oil pressure in the oil passage 26 is the oil pressure in the oil passage 46, that is, the lock-up solenoid 58
The hydraulic pressure is adjusted in inverse proportion to the duty ratio. Since the oil pressure on the release chamber 22 side is lower than the oil pressure on the apply chamber 20 side, the facing 30 of the lock-up clutch 18 is pressed against the friction surface of the cover 28. The force for pressing the lock-up clutch 18 is controlled by the lock-up solenoid 58 as described above.

Next, set the duty ratio of the lock-up solenoid 58 to 1.
00%, the opening 60 is completely opened. Therefore, the oil pressure in the oil passage 46 becomes 0, and the spool 34 is completely switched to the left side in the figure. In this state, oil pressure is supplied from the oil passage 24 to the apply chamber 20 and the lock-up clutch 18 is completely engaged, so that almost no oil flows into the oil passage 26.

Next, control of the lock-up clutch 18 according to the present invention will be explained.

For example, when shifting from a gear position in which the lock-up clutch 18 is in a slipping state to another gear position in which the lock-up clutch 18 is in a slipping state, control is performed according to the control flow shown in FIG. That is, first, the engine rotation speed signal Ne from the engine rotation speed sensor 66, the output shaft rotation speed signal NO from the output shaft rotation speed sensor 68, and the throttle opening signal from the throttle opening sensor 70 are read (step 10).
0). Next, it is determined whether or not the gear is being shifted (step 102).
, if the gear is not being changed, the current gear ratio G is determined (step 104). Next, output shaft rotation speed No. and gear ratio G
The rotational speed (Nt=GXNo) of the turbine runner is calculated from (step 106). Next, the difference between the engine rotational speed Ne and the calculated turbine rotational speed Nt, that is, the torque converter slip amount R=N e - N t is calculated (step 108). Next, the speed difference R is compared with a preset target speed difference S (
Step 110), if R is larger than S, output a signal to operate the solenoid 58 to lower the oil pressure in the release chamber 22. On the other hand, if R is smaller than S, the pressure in the release chamber 22 is output. A signal is output to activate the solenoid 58 to increase the oil pressure (step 114).

On the other hand, if the gear is being shifted in step 102, the time from the start of gear shifting is measured (step 116), and then the predetermined feedback prohibition time (this is the time required for gear shifting, which is set in advance) has elapsed. If the time has elapsed, the shift flag is cleared (step 120), and the process proceeds to step 104. If the feedback prohibition time has not elapsed, a preset constant duty ratio is output according to the throttle opening (step 122). As a result, by the above-described control, the speed difference of the lock-up clutch 18 is feedback-controlled to a preset value during non-shifting, and the lock-up clutch 18 is placed in a slipping state. On the other hand, during gear shifting, the solenoid 58 is controlled to a predetermined duty ratio, and the lock-up clutch 18 is brought into a slipping state at a predetermined ratio.

In the above embodiment, a constant duty ratio is output in step 122, but the first time t1 is
The second duty ratio D2 (for example, D2>DI) may be output for the remaining time t2. Furthermore, as in the embodiment shown in FIG. 4, until the sign of the rate of change in engine speed changes (for example, while the engine speed is increasing as the gear shift progresses).
The first duty ratio may be set as D2, and thereafter (after the engine speed starts to decrease) the second duty ratio may be set as D2 (steps 124 to 128).

(g) As described in detail, according to the present invention, the feedback control of the lock-up clutch slip is stopped and a preset duty ratio is output to the lock-up control solenoid. It is possible to control the lock-up clutch to a slipping state even during gear shifting without requiring a turbine rotational speed sensor.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the relationship between the constituent elements of the present invention, Fig. 2 is a diagram showing an embodiment of the invention, Fig. 3 is a diagram showing a control flow, and Fig. 4 is a diagram showing another control flow. It is. Figure 1

Claims (1)

[Scope of Claims] 1. In a lock-up clutch control device in which the operating state of a lock-up clutch capable of connecting a pump impeller side and a turbine runner side of a fluid transmission device is controlled by a solenoid whose duty ratio is controlled, an engine An engine rotation speed sensor that detects the rotation speed, an output shaft rotation speed sensor that detects the rotation speed of the output shaft, a gear ratio detection means that detects the gear ratio during non-shifting, and a signal from the output shaft rotation speed sensor. a turbine rotation speed calculation means for calculating the rotation speed of the turbine runner based on the signal from the gear ratio detection means; and a turbine rotation speed calculated by the engine rotation speed detected by the engine rotation speed sensor and the turbine rotation speed calculation means. non-shifting slip control means for feedback-controlling the operation of the solenoid in a desired case during non-shifting so that the difference between the two and A lock-up clutch comprising: slip control means during gear shifting that stops feedback control of the slip control means and outputs a preset duty ratio signal to a solenoid corresponding to at least a throttle opening degree. control device. 2. The duty ratio set in the slip control means during a shift is a constant first duty ratio for t_1 hours after the shift is commanded, and is a constant second duty ratio for t_2 hours after the lapse of t_1 hours. 2. A control device for a lock-up clutch according to item 1. 3. The duty ratio set in the slip control means during gear shifting is the first duty ratio from when the gear shift is commanded until the sign of the rate of change in engine speed changes, and after the sign changes, the duty ratio is the second duty ratio. 2. The lock-up clutch control device according to claim 1, wherein the lock-up clutch is a