JP2923073B2 - Lockup device failure detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure detecting device for a lock-up device.

[0002]

2. Description of the Related Art A lock-up clutch is a device capable of connecting a pump impeller of a fluid transmission with a turbine runner. By fastening this, slippage of the fluid transmission device can be eliminated (see, for example, JP-A-63-172058). If such a lock-up clutch fails and does not operate at all, it will always be in a fluid transmission state. In this case, there is a problem such as a decrease in transmission efficiency, but other parts are not secondarily damaged. However, when the lock-up clutch is in a failure state in which the lock-up clutch is operated by insufficient hydraulic pressure, the lock-up clutch continues to rotate in a frictional state, and a large amount of heat is generated. As a result, the temperature of the hydraulic oil increases, which may adversely affect other seal members, clutches, brakes, and the like. An object of the present invention is to solve such a problem.

[0003]

SUMMARY OF THE INVENTION According to the present invention, when the rotation speed difference between the rotation speed of the pump impeller and the rotation speed of the turbine runner is equal to or greater than a predetermined value and the temperature of the hydraulic oil rapidly increases, The above problem is solved by determining that the lockup device has failed. That is, a failure detection device for a lock-up device according to the present invention includes a pump rotation speed sensor that detects a rotation speed of a pump impeller, a turbine rotation speed sensor that detects a rotation speed of a turbine runner, a rotation speed of a pump impeller, and a rotation speed of a turbine runner. Calculating means for calculating a rotation speed difference from the rotation speed of the hydraulic fluid, slip determination means for determining whether or not the rotation speed difference is equal to or greater than a predetermined value in a state where the lock-up device is commanded to be engaged, and An oil temperature sensor for detecting a temperature, an oil temperature change rate calculating means for calculating a change rate of the oil temperature detected by the oil temperature sensor, and a slip speed determining means for determining that the rotational speed difference is equal to or more than a predetermined value, and If it is determined that the change rate of the oil temperature obtained by the change rate calculating means is equal to or more than a predetermined value in the direction of increasing the oil temperature, the lock-up device is disabled. And a, and failure determining means for determining that.

[0004]

When the lock-up device is fastened in a normal state, there is no slippage between the pump impeller and the turbine runner, and both rotate at the same rotation speed. If slippage of the lock-up device occurs for some reason, a rotation speed difference occurs between the pump impeller and the turbine runner. If a rotational speed difference equal to or greater than a predetermined value occurs and the temperature of the hydraulic oil rapidly increases, it is determined that the lockup device has failed. Thereby, for example, a warning is given to the driver,
Appropriate response actions can be taken automatically.

[0005]

FIG. 2 shows an embodiment of the present invention. Engine 1
0 is connected to a torque converter 2 having a lock-up clutch 40 (lock-up device).
It has 0. The lock-up clutch 40 can connect the pump impeller 42 and the turbine runner 44.
The control unit 18 of the automatic transmission 12 includes a pump rotation speed sensor 24, a turbine rotation speed sensor 26,
And a signal from the oil temperature sensor 28. The pump rotation speed sensor 24 can detect the rotation speed of the pump impeller 42 (this is the same as the rotation speed of the engine 10, so the pump rotation speed sensor 24 is actually an engine rotation speed sensor). Turbine rotation speed sensor 2
Reference numeral 6 can detect the rotation speed of the turbine runner 44.
The oil temperature sensor 28 can detect the temperature of the hydraulic oil of the automatic transmission 12.

[0006] Regarding the failure of the lockup device, the control unit 18 makes a determination according to the control flow shown in FIG. First, the lock-up clutch 40
It is determined whether or not the engagement command is output (step 100). If the engagement command is output, it is determined whether or not each sensor is normal (the same 102). The rotational speed NP is read (104), the rotational speed NT is read from the turbine rotational speed sensor 26 (106), and the temperature of the hydraulic oil is read from the oil temperature sensor 28 (108). Next, a difference S between the two rotational speeds is calculated (110). That is, S =
Perform NP-NT calculation. Next, it is determined whether the calculated S is larger than a predetermined value S1 (112).
If S is greater than S1, the oil temperature rise rate R is calculated (114). The increase rate R of the oil temperature is obtained from the difference between the oil temperature of the current routine and the oil temperature of the previous routine. It is determined whether the oil temperature rise rate R thus obtained is equal to or greater than a predetermined value R1 (116), and if it is equal to or greater than the predetermined value R1, it is determined that a failure has occurred, and a failure flag F is set (11).
8). On the other hand, if the conditions are not satisfied in steps 100, 102, 112, and 116, the failure flag F is not set. Step 110 constitutes an arithmetic means, step 114 constitutes an oil temperature change rate judging means, step 112 constitutes a slip judging means, and step 116 constitutes a failure judging means. Eventually, if the control causes slippage of a predetermined amount or more between the pump impeller 42 and the turbine runner 44 and the temperature of the hydraulic oil rapidly rises, it is determined that a failure has occurred. If it is determined that a failure has occurred, the driver can be notified of this by, for example, an alarm unit, and can be configured not to output an engagement command for the lock-up clutch 40 regardless of, for example, operating conditions. Thereby, it is possible to prevent the occurrence of secondary damage due to the temperature rise of the hydraulic oil.

[0007]

As described above, according to the present invention, when there is more than a predetermined slippage between the pump impeller and the turbine runner and the temperature of the hydraulic oil rises rapidly, the lock-up device is used. Is determined, the failure of the lockup device can be reliably determined, and based on this, the occurrence of secondary damage can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between components of the present invention.

FIG. 2 is a diagram showing an embodiment of the present invention.

FIG. 3 is a diagram showing a control flow.

[Explanation of symbols]

 18 Control unit 24 Pump rotation speed sensor 26 Turbine rotation speed sensor 28 Oil temperature sensor 40 Lock-up clutch (lock-up device)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 61/14

Claims (1)

(57) [Claims] 1. A failure detection device for a lock-up device capable of fastening a pump impeller and a turbine runner, wherein a pump rotation speed sensor detects a rotation speed of the pump impeller and a turbine rotation speed sensor detects a rotation speed of the turbine runner. Calculating means for calculating a rotation speed difference between the rotation speed of the pump impeller and the rotation speed of the turbine runner; and determining whether the rotation speed difference is equal to or greater than a predetermined value in a state where the lock-up device is commanded to be engaged. Slip determining means for determining; an oil temperature sensor for detecting the temperature of the hydraulic oil; oil temperature change rate calculating means for calculating a change rate of the oil temperature detected by the oil temperature sensor; Is greater than or equal to a predetermined value, and the rate of change of the oil temperature determined by the oil temperature change rate calculating means is equal to or greater than a predetermined value in the direction of increasing the oil temperature And a failure judging means for judging that the lock-up device has failed when it is determined that the lock-up device has failed.