JPH0540858U - Leak inspection device for sealing element - Google Patents

Abstract

(57) [Summary] [Purpose] To grasp the difference in the amount of leakage due to the phase of the sealing element A and the axis 3 and perform highly accurate defect inspection. [Structure] Housing ₁ for tightly fitting the outer diameter portion A ₁ of the sealing element A
Casings 1 and 2 in which casings 1 and 22 are formed, and a shaft 3 which is rotatably and rotatably inserted into the housings 11 and 22 from the shaft hole 21 of the casing ₂ and contacts the inner diameter portion A ₂ of the sealing element A.
And an output port 24 opened to the second chamber 23 on the other side, and an input port 13 opened to the first chamber 12 on the one side in the axial direction of the sealing element A. The working fluid is supplied to the one chamber 12, and the shaft 3 is arbitrarily rotated so that the leakage of the working fluid from the sealing element A can be measured.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a leak inspection device for inspecting the sealing performance of sealing elements such as oil seals for sealing the shaft circumference and various packings.

[0002]

[Prior Art]

 In sealing elements such as oil seals and various packings, if there is a flaw, a sink mark during molding, or a defect such as foreign matter in the inner diameter part that is in close contact with the outer peripheral surface of the shaft, sufficient sealing performance cannot be obtained, so it is manufactured. It is necessary to inspect the quality of the inner diameter of the sealing element, and the conventional inspection is performed by visually inspecting the appearance or using a leak inspection device.

FIG. 3 shows a conventional leak inspection device used for the above inspection. In this leak inspection device, an outer diameter portion A ₁ of an oil seal A, which is a sealing element to be inspected, is placed between accommodating portions 103 and 104 formed on opposed surfaces of a pair of casings 101 and 102 that are axially opposed to each other. The inner peripheral surface of the inner diameter lip portion A ₂ of the oil seal A is fitted to the outer peripheral surface of the shaft 105 which is tightly fitted and integrally protruded from the casing 102 and finished to have substantially the same diameter dimension and surface roughness as the actual machine shaft. contacting the, in this state, the hydraulic fluid from the input port 106 opened in the casing 1 01 to the first chamber 1 07 as the rear side of the inner diameter lip portion a ₂ and the pressure supply, the front side of the inner diameter lip portion a ₂ By measuring the pressure or flow rate of the working fluid that has leaked into the second chamber 108, or by measuring the amount of pressure drop on the input side, and comparing this measured value with a preset allowable value. Seal It is intended to determine the presence or absence of a defect, such as impairing.

[0004]

[Problems to be solved by the device]

However, in the leak inspection using the above-mentioned conventional inspection device, the error in the circularity of the inner diameter lip portion A ₂ of the oil seal A or the outer peripheral surface of the shaft 105, which is the sealing element to be inspected, or the surface roughness in the circumferential direction. If there is a large amount of non-uniformity, the amount of leakage of the working fluid from between the inner diameter lip portion A ₂ and the shaft 105 may differ depending on the relative position of the oil seal A and the shaft 105 in the circumferential direction, as shown in FIG. There was no accurate inspection. That is, if the leakage amount is below the allowable value at a certain phase and it is determined as a non-defective product due to the relative phase in the assembled state of the oil seal A and the shaft 105, the phase is changed and the inspection is performed again. A gap δ may occur around the shaft and the leakage amount may exceed the allowable value. Therefore, in the conventional inspection method performed without changing the phase of the inner diameter lip portion A ₂ and the shaft 105, the defective product is regarded as a good product. There was a possibility of making a wrong decision.

The present invention has been made in view of the above problems, and an object of the present invention is to grasp the difference in the amount of leakage due to the phase of the sealing element and the shaft and perform a highly accurate defect inspection. There is nothing to do.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, a leak detecting device for a sealing element according to the present invention comprises a casing in which a housing portion for tightly fitting an outer diameter portion of a sealing element is formed, and an axial hole of the casing is airtight into the housing portion. And a shaft which is rotatably inserted into contact with the inner diameter portion of the sealing element, the input port opening to the first chamber on one axial side of the sealing element and the output port opening to the second chamber on the other side. Is provided.

[0007]

[Action]

 According to the leak inspection apparatus of the present invention, the sealing element for inspection is tightly fitted in the housing formed in the casing, and the inner diameter of this sealing element is the outer circumference of the shaft rotatably inserted into the axial hole of the casing. It is fitted into the surface, and in this state, the working fluid is pressurized and supplied from the input port opened in the casing to the first chamber on the one axial side of the sealing element, and the fluid loss due to leakage from the sealing element is measured. is there. At this time, by rotating the casing and the shaft relative to each other, it is possible to perform the leak inspection while arbitrarily changing the relative phase between the sealing element and the shaft. Data is obtained.

In the above-mentioned leak test, the sealing element is measured by measuring the loss of the working fluid supplied to the first chamber on the one side in the axial direction of the sealing element while rotating the shaft and the sealing element relatively at a constant speed. It is possible to determine the defect. Also, after measuring the loss of the working fluid in the first chamber with the shaft and the sealing element stopped, the shaft and the sealing element are relatively rotated by a predetermined phase to stop, and the measurement is performed again. By repeating it, the defect can be judged from the largest measured value of the leakage amount obtained in each phase. Also, by measuring the loss of the working fluid in the first chamber while rotating the shaft and the sealing element relatively in one direction, and then measuring the loss of the working fluid in the first chamber while rotating in the opposite direction, It is also possible to grasp the difference in the amount of leakage, which is affected by the direction of the defect of the element and is influenced by the direction of rotation.

[0009]

【Example】

 FIG. 1 shows an embodiment in which the leak inspection apparatus according to the present invention is applied for leak inspection of an oil seal. A pair of casings 1 and 2 are coaxially aligned and arranged to face each other in an axial direction. , A shaft 3 rotatably inserted in the shaft hole 21 of the casing 2. The shaft 3 is rotated by a driving means such as a motor (not shown) and has a diameter and surface roughness substantially equal to those of an actual shaft. The packing 4 is provided between the shaft hole 21 and the outer peripheral surface of the shaft 3. It is sealed with.

The casing 1 is formed with a recessed portion 11 on the surface 1 a facing the casing 2, and the casing 2 has a part of the shaft hole 21 extended on the surface 2 a facing the casing 1. An oil seal A, which is a sealing element to be inspected, has an outer diameter portion A ₁ tightly fitted in a sandwiched state between the accommodating portions 11 and 22 facing each other. At the same time, the inner diameter lip portion A ₂ comes into contact with the outer peripheral surface of the shaft 3 reaching the inside of the housing portions 11 and 22.

In the assembled state shown in the drawing, the inner peripheral spaces of the housing parts 11 and 22 are divided into two chambers 12 and 23 in the axial direction by an oil seal A which is in contact with the inner side surfaces of the housing parts 11 and 22 and the outer peripheral surface of the shaft 3. Partitioned. An input port 13 is opened at the axial center of the casing 1 so as to face the first chamber 12, which is the rear side of the inner diameter lip A ₂ of the oil seal A, and the inner diameter of the oil seal A is provided in the casing 2. An output port 24 is opened facing the second chamber 23 which is the front side of the lip portion A ₂ .

Next, when performing a leak inspection of the oil seal A using the leak inspection device having the above-described configuration, first, the oil seal A is installed in the state shown in the figure, and the input port 13 is connected to a working fluid supply source (not shown). Then, a working fluid such as air, water, oil or an inert gas is injected into the first chamber 12 on the back side of the oil seal A, and a pressure is applied to the oil seal A from the back side by this working fluid. Then, the working fluid leaks into the second chamber 23 by pushing the inner diameter lip portion A ₂ of the oil seal A ₂ and then flows out from the output port 24. The amount of leakage from the oil seal A depends on whether the inner peripheral surface of the inner diameter lip portion A ₂ facing the outer peripheral surface of the shaft 3 is flawed or there is a defect a (see FIG. 2) due to sink marks or foreign matter during molding. Since they are different, it is possible to measure the loss amount of the working fluid in the first chamber 12 due to leakage, and compare the measured value with a preset allowable value to determine the presence or absence of the defective portion a. The leak amount, that is, the loss of the working fluid in the first chamber 12 is measured by detecting the flow rate or the pressure of the working fluid leaked to the second chamber 23 side, or by measuring the pressure drop amount of the working fluid applied to the first chamber 12. Is done by detecting.

At this time, if the inner diameter lip portion A _{2 of} the oil seal A or the roundness error or the surface roughness of the outer peripheral surface of the shaft 3 is large, the phase of the oil seal A and that of the shaft 3 cause the working fluid to move. Since the leak amount is different, an accurate quality judgment cannot be made unless the phase of the inner diameter lip portion A ₂ and the shaft 3 is changed. Therefore, the working fluid is pressurized and supplied to the first chamber 12, and the shaft 3 is continuously rotated at a constant speed, for example, one rotation or more in the arrow X direction in the drawing, and the leakage amount at this time is measured. The presence or absence of defects can be accurately determined. In this case, the amount of leakage that gradually changes as the shaft 3 rotates is continuously measured to determine whether or not the measured value may exceed the allowable value, or the total amount of leakage during rotation of the shaft 3. Judge from.

As another inspection method, a working fluid is injected from the input port 13 into the first chamber 12, pressure is applied to the oil seal A from the rear side, and the leakage amount of the leakage is measured when the shaft 3 is stopped. After performing the measurement, rotate the shaft 3 in the direction of the arrow X by an arbitrary angle (for example, 90 °), stop at that position, and measure the amount of leakage again, for any number of times (for example, 3 times). It is also possible to make a pass / fail judgment by repeatedly comparing the maximum value of the measured values with the allowable value.

As still another inspection method, the shaft 3 is continuously rotated at a constant speed for one rotation or more in the direction of the arrow X in the drawing at a constant speed, the leak amount at this time is measured, and then the shaft 3 is rotated along the arrow X. Similarly, rotate in the opposite direction and measure the amount of leakage at this time. In this case, similar to the above, even if the leak amount of the working fluid is different depending on the mutual phases of the oil seal A and the shaft 3, it is possible to make an accurate judgment as to whether or not the measured value depends on the directionality of the defective portion a. The effect that the uncertain factor of can be eliminated can be obtained. That is, as shown in FIG. 2, if the defect portion a existing in the inner diameter lip portion A ₂ of the oil seal A has directionality, the amount of leakage varies depending on the rotation direction of the shaft 3, but the shaft 3 rotates in the normal and reverse directions. By making the measurements respectively, it is possible to prevent such an erroneous determination due to the difference in the leakage amount.

Although the illustrated embodiment has been described only for the case where the oil seal is an inspection target, the present invention can be similarly applied to the leak inspection of other sealing elements such as various packings.

[0017]

[Effect of the device]

 According to the leak inspection device for a sealing element of the present invention, it is possible to detect the difference in the leakage amount in each phase by measuring the leakage amount while arbitrarily changing the relative phase of the sealing element and the shaft. It is possible to accurately determine the presence or absence of a defective portion of the sealing element, and in addition, it is possible to detect the difference in the amount of leakage depending on the rotation direction depending on the directionality of the defect of the sealing element.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a leak inspection apparatus according to the present invention, together with a mounted state of an oil seal A which is a sealing element to be inspected.

FIG. 2 is a perspective view of a partially cut oil seal having a defect.

FIG. 3 is a cross-sectional view showing an example of a conventional leak inspection device together with a mounted state of an oil seal A which is a sealing element to be inspected.

FIG. 4 is a cross-sectional view taken along line I-I of FIG.

[Explanation of symbols]

1, 2 Casing 1a, 2a Opposite surface 3 Shaft 4 Packing 11, 22 Storage part 12 First chamber 13 Input port 21 Shaft hole 23 Second chamber 24 Output port A Oil seal (sealing element) A ₁ Outer diameter part A ₂ Inner diameter Lip part (inner diameter part) a Defect part

Claims (1)

[Scope of utility model registration request] 1. Casings 1 and 2 formed with housings ₁₁ and 22 for tightly fitting an outer diameter portion A ₁ of a sealing element A, and airtight from shaft holes 21 of the casing 2 into the housings 11 and 22. And a shaft 3 which is rotatably and rotatably inserted to contact the inner diameter portion A ₂ of the sealing element A and which is opened to a first chamber 12 on one axial side of the sealing element A to supply a working fluid. Output port 2 opening to the port 13 and the second chamber 23 on the other side
4. The leak inspection device for a sealing element, which is provided with 4.