JP2772478B2 - Clutch piston leak test method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a leak test method for inspecting an assembled state of a clutch piston in an assembly process of a clutch piston incorporated in an automatic transmission.

(Prior art) Conventionally, when a visual inspection such as a casting defect or a crack is impossible for an article having a hollow portion inside, air of a predetermined pressure is supplied, and the residual pressure of the sealing pressure is measured to measure the quality. It is known to perform a check (see Japanese Utility Model Laid-Open No. 61-10543).

This technology is also used in the process of assembling an automatic transmission, in which a clutch piston is assembled in a clutch drum, and a test is performed to determine whether or not the working chamber formed therebetween is properly sealed.

(Problems to be Solved by the Invention) In this leak test, the supply pressure is set to about 4 kg / cm ² in consideration of the fact that air is used in place of the original oil and the leakage property is higher than that of the oil. Although discrimination is made based on the residual pressure after a wrong time at a predetermined time from the air cut, those which are determined to be NG as a result of falling below the residual pressure set level are disassembled and repaired.

However, even if it was determined to be NG, it was not clear what was wrong, and if it was reassembled and the leak test was performed again, it might be normal and the productivity was hindered.

Therefore, when various tests were conducted, it was found that the seal member interposed between the clutch drum and the clutch piston did not sufficiently fit into the seal groove. Was determined to be caused by not moving to the far side.

(Means for Solving the Problem) Therefore, the present invention eliminates the erroneous determination of leaks due to poor conformity in the seal groove of the seal member, eliminates the erroneous determination in the leak test, and enables an efficient leak test. As described above, prior to supply of air at a predetermined pressure, a cycle of supplying and discharging air having a pressure higher than the predetermined air pressure is repeated a plurality of times.

(Operation) The seal member, which is mounted in the seal groove of the clutch drum or the clutch piston and has an unstable position and posture, is intermittently pressed with a pressure higher than the test air pressure. It becomes calm by adapting in the interior, and careless abnormal leakage due to poor adaptation in the subsequent leak test is eliminated.

(Effects) As is apparent from the above description, the present invention does not cause abnormal leakage due to poor fitting of the seal member by the leak test method of the clutch piston, and therefore determines only the original defect. As a result, an unnecessary post-processing operation can be omitted, and an efficient leak test can be performed.

(Example) Hereinafter, an example is described based on a drawing.

FIG. 1 is an explanatory diagram of a circuit used for a leak test, and FIG. 2 is an explanatory diagram of control showing a relationship between time and air pressure.

Is W ₁ is a clutch drum in the figure, the clutch piston W ₂ fitted in the inside, of the clutch piston, the seal member W _5, W _6, respectively in the seal groove W _3, W ₄ of the outer periphery is attached I have. The inner peripheral wall of the clutch drum W ₁ has the oil feed port W ₈ that communicates with the working chamber W ₇ partitioned by the clutch piston W _2, air supply port of the air leak test circuit 1 to be described later is connected.

The air leak test circuit 1 includes a circuit 2 for high pressure and a circuit 3 for low pressure from an air compressor P as air generating means for increasing the air pressure. For example, a pressure regulating valve 4 for regulating the pressure to 5.5 kg / cm ² and a direction switching valve 5 are interposed in the high pressure circuit 2 in series. In the low-pressure circuit 3, a pressure regulating valve 6 for regulating the pressure to 4.0 kg / cm ² and an on-off valve 7 are provided in series, and a pressure detector 8 is connected downstream of each valve. .

An air leak test is performed using this circuit 1. First, the solenoids at both ends of the directional control valve 5 are alternately excited to repeatedly supply and discharge high-pressure air three times (A
Zone), the direction switching valve 5 is set to the neutral position, the on-off valve 7 is opened, and low-pressure air is supplied for a certain period of time (B zone). Thereafter, the on-off valve 7 is closed and the working chamber W ₇ after a certain period of time is closed.
Is detected by the pressure detector 8 (C zone).

As a result, it determines that the long residual pressure predetermined value P ₁ or less, abnormal leakage occurs.

According to this leak test method, in order to act on the intermittently operating chamber W ₇ a high-pressure air, the sealing member W _5, W ₆ is stable in the sealing groove _3, W within _4, no inadvertent air leakage is .

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is an air leak test circuit used in the present invention, and FIG. 2 is a control characteristic diagram showing the relationship between time and pressure indicating steps of air supply control. .

Claims (1)

(57) [Claims] A working chamber defined by a clutch drum and a clutch piston, which is interposed between the clutch drum and the clutch piston and sealed by a seal member mounted in a seal groove, has a predetermined shape. A method of leak testing a clutch piston that supplies air pressure and detects a pressure drop state of the working chamber after the supply cut of the air pressure to determine a leak state of the working chamber. Prior to supplying a predetermined air pressure and determining a leak state of the working chamber, a cycle of supplying and discharging an air pressure larger than the predetermined air pressure to the working chamber is repeated a plurality of times. And a clutch piston leak test method.