JPH07239284A - Leak inspection device - Google Patents

Abstract

PURPOSE:To provide a leak inspection device capable of inspecting even a fine flaw, capable of instantly feeding back the data of product abnormality to a process and capable of realizing the automation of an inspection process. CONSTITUTION:A leak inspection device inspecting the leakage of a dust cover 4 having a lip part 1, a skirt part 2 and a film part 3 has the first jig 5 fitted to the skirt part, the second jig 6 fitted to the lip part 1 and made relatively movable so as to approach and separate with respect to the first jig 5 and the vacuum pump 7 sucking the lip part 1 and skirt part 2 respectively connected to first and second base stands. Further, an air pump 8 generating positive pressure in the space S formed by the first and second jigs 5, 6 and the dust cover 4 and a pressure gauge 9 inspecting the pressure state of the space S set to posite pressure are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting a leak of an object which forms a sealed space inside when it is assembled to an object, and is used, for example, for a leak inspection of a film portion of a dust cover of a ball joint. The present invention relates to a preferable leak inspection device.

[0002]

2. Description of the Related Art For example, a ball joint composed of a ball having a swing shaft and a housing is provided with a dust cover for preventing dust and water from entering the sliding portion and maintaining sliding performance. It is installed. This type of dust cover has an internal space formed by fixing the mounting part at one end to the housing and the mounting part at the other end to the swing shaft, and fills lubricating oil such as grease as necessary. To be done.

As described above, in the ball joint which is frequently used in the suspension system of an automobile, the housing and the swing shaft swing relatively violently, and therefore the dust cover whose both ends are fixed between them. Also excellent durability is required. For example, if a defective material filling occurs during molding of the dust cover, that portion may become a thin film and may be damaged during use. Therefore, leakage inspection of the film portion is performed on the molded dust cover.

[0004]

However, in the conventional leak inspection, the visual evaluation by an inspector is the mainstream, and it is extremely difficult to find a fine film defect or a defect such as a thin film phenomenon. Therefore, as a sampling inspection, a durability test with a dust cover attached to the actual ball joint was conducted, but it is difficult to feed back the occurrence of film defects to the process in real time, and it also leads to automation of the inspection process. There was a problem of not having.

The present invention has been made in view of the above-mentioned problems of the prior art. It is possible to detect even minute defects and to immediately feed back information on product defects to the process. An object of the present invention is to provide a leak inspection device that can realize the automation of the inspection process.

[0006]

In order to achieve the above object, a leak inspection apparatus of the present invention is a leak inspection apparatus for performing a leak inspection of an inspection object having an attachment portion and a film portion,
A first jig fitted to one of the mounting portions and a second jig fitted to the other of the mounting portions and capable of moving toward and away from the first jig relatively. A tool, a negative pressure source connected to the first base and the second base to adsorb the respective mounting portions, and the first jig, the second jig, and the object to be inspected. A positive pressure source for making a positive pressure in the space, and a verification means for verifying a pressure state of the space made positive by the positive pressure source are provided.

[0007]

[Function] When performing a leak inspection of a film part of an object to be inspected,
First, one of the attachment parts of the inspection object is fitted to the first jig. Next, the second jig is brought close to the first jig and the second jig is fitted to the other mounting portion of the object to be inspected. As a result, a space defined by the first jig, the second jig, and the inspection object is formed inside the inspection object.

When the object to be inspected is set on the first jig and the second jig in this way, the attachment portion of the object to be inspected is then adsorbed by the negative pressure source. Since the mounting portion of the object to be inspected has a structure in which the sealing performance is ensured when it is assembled to the object to be assembled, the inside of the space is sealed by suction by the negative pressure source.

From this state, a positive pressure source is used to make the space of the object to be inspected positive, and a pressure is applied to the film portion of the object to be inspected from the inside. If there is a fine defect in the film portion, the pressure in the space of the object to be inspected decreases, and if there is no defect, the initial value of the internal pressure is maintained. Such a pressure state is monitored for a certain period of time by the verification means, and if a pressure decrease is observed, it is assumed that there is a defect in the film portion.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a device configuration diagram showing a leak inspection device according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of an essential part for explaining a mounting state of an inspection object of the embodiment. First, the leak inspection device of the present invention will be described by exemplifying a dust cover of a ball joint as an inspection object.

As shown in FIGS. 1 and 2, the dust cover 4 according to the present embodiment is a cylindrical rubber product having both ends opened, and has a small-diameter mounting portion (lip portion).
1 is fitted and attached to the swing shaft of the ball. A seal lip 1a is formed on the inner peripheral surface of the mounting portion 1 so as to be in close contact with the swing shaft of the ball to ensure sealing performance.
In addition, "10" shown in FIG. 2 is a metal ring insert-molded in order to enhance the strength of the mounting portion. On the other hand, the mounting portion 2 mounted on the housing side of the ball joint
The structure is formed into various shapes depending on the shape of the housing and the fixing means, but the mounting portion (skirt portion) 2 of the present embodiment is formed with a flange 2a that spreads outward, and for example, a fixing band is provided inside the flange 2a. Is installed.

Such a dust cover 4 is mainly made of a rubber material and is manufactured by, for example, an injection molding method.
Accordingly, when the molten rubber is injected into the cavity, if the material is hindered from wrapping around, a partial defect will occur in the dust cover. Also, if air is mixed in the molten material, pinholes etc. will be generated, and various product defects that deteriorate the sealing performance even when molding is performed without properly controlling injection conditions, cooling conditions, etc. May occur.

Therefore, the leak inspection of the dust cover 4 is performed by using the leak inspection apparatus of the present invention described below. This inspection is performed after molding the dust cover and before mounting the dust cover on the ball joint. The leak inspection by the leak inspection apparatus of the present invention may be a sampling inspection, but it can also be performed on all manufactured dust covers.

As shown in FIG. 1, the leak inspection apparatus of this embodiment has two jigs 5 and 6 which are relatively movable toward and away from each other. The skirt portion 2 of the dust cover is fitted to the first jig 5, and the lip portion 1 of the dust cover is fitted to the second jig 6. In this embodiment, the first
The jig 5 is fixed, and the second jig 6 is provided so as to be vertically movable with respect to the first jig 5 by the fluid cylinder 11 or the like.
However, as long as the first jig 5 and the second jig 6 can relatively move toward and away from each other, the present invention is not limited to this embodiment, and the second jig 6 can be fixed. And the first jig 5
May be movable, or both 5 and 6 may be movable.

The first jig 5 is formed with a convex portion 13 into which the skirt portion 2 of the dust cover 4 is fitted, and the side surface of the convex portion 13 regulates the inner surface of the dust cover 4 so that the ball Make sure the body is in the proper posture to be attached to the joint. Around the foot of the convex portion 13, a concave portion 14 is formed entirely or partially, and is connected to a vacuum pump (negative pressure source) 7 through a through hole 15 penetrating the first jig 5. ing. In this embodiment, the concave portions 14 are partially formed around the base of the convex portion 13, and the through holes 15 communicating with the respective concave portions 14 are connected to the vacuum pump 7, respectively. As a result, when the skirt portion 2 of the dust cover is fitted into the convex portion 13 and the vacuum pump 7 is operated, the end surface of the skirt portion 2 covering the concave portion 14 is adsorbed by the first jig 5.

On the other hand, the second jig 6 provided above the above-mentioned first jig 5 is composed of a main body 6a and a slide plate 6b movable vertically with respect to the main body 6a. Is moved toward and away from the first jig 5 together with the slide plate 6b by the fluid cylinder 11. Further, the slide plate 6b is a member for removing the lip portion 1 of the dust cover from the second jig 6 after the leakage inspection is completed, and the slide plate 6b is attached to the main body 6a by the fluid cylinder 12 provided in the main body 6a. Move up and down.

The second jig 6 is formed with a convex portion 16 that fits into the lip portion 1 of the dust cover, and the side surface of the convex portion 16 has an annular concave portion for adsorbing the lip portion 1. 17 are formed. The positioning of the lip portion 1 and the second jig 6 is performed by the positioning surface 18 formed around the foot of the convex portion 16, and when the upper surface of the lip portion 1 and the positioning surface 18 come into contact with each other, the annular concave portion is formed. 17 faces the inner surface of the lip portion 1. The annular recess 17 communicates with the through holes 20 formed in the second jig 6 through the through holes 19 formed in four equal distributions, and the through holes 20 are connected to the vacuum pump 7. There is. As a result, when the vacuum pump 7 is operated, negative pressure acts on the annular recess 17 via the through holes 20 and 19, and the lip portion 1 is attracted to the second jig 6.

A through hole 21 is provided in a space S formed by the first jig 5, the second jig 6 and the dust cover 4.
Air is supplied from the air pump (positive pressure source) 8 via the. The air pump 8 supplies the air of a predetermined pressure into the space S of the dust cover, so that the first jig 5
Further, a positive pressure is applied from the inside of the dust cover 4 suction-held by the second jig 6, thereby bulging the film portion 3 of the dust cover and observing the pressure change. Therefore, it is preferable to set the supply pressure from the air pump 8 according to the specifications and uses of the dust cover 4.

The verification means 9 provided in the air pump 8 comprises, for example, a pressure gauge, and observes the internal pressure of the dust cover 4 to which a positive pressure is applied. Then, after the pressure inside the dust cover S reaches a predetermined value by the air pump 8,
The state of the pressure value is detected. In addition to the pressure gauge, the verification means 9 may use, for example, another pressure sensor or a flow meter.

Next, the operation will be described. The leak inspection of the film portion 3 of the dust cover is performed as follows. First, the skirt portion 2 of the dust cover is fitted into the convex portion 13 of the first jig 5, and then the second jig 6 is lowered with respect to the first jig 5 to move the second jig 6 to the second jig 6. The convex portion 16 of the jig is fitted into the lip portion 1 of the dust cover. At this time, the dust cover 4 and the second jig 6 are positioned by bringing the upper surface of the lip portion 1 into contact with the positioning surface 18 formed on the second jig. As a result, inside the dust cover 4,
A space S defined by the first jig 5, the second jig 6, and the dust cover 4 is formed.

When the dust cover 4 is set on the first jig 5 and the second jig 6 in this way, the vacuum pump 7
By this, the lip portion 1 and the skirt portion 2 of the dust cover are attracted. However, this adsorption is caused by the dust cover 4 described above.
You may go at the time of setting. In this case, since the lip portion 1 and the skirt portion 2 of the dust cover have a structure in which sealing performance is ensured when they are assembled to the swing shaft of the ball joint and the housing, the space S is sucked by the vacuum pump 7. The inside will be sealed.

From this state, the air pump 8 is used to supply air into the space S of the dust cover to make a positive pressure, and the film portion 3 of the dust cover is internally pressurized. if,
If the film portion 3 has a fine defect, the pressure in the space S of the dust cover decreases, and if there is no defect, the initial value of the internal pressure is maintained. Such a pressure state is monitored by the pressure gauge 9 for a certain period of time, and if a pressure decrease is observed, it is called to the outside that the film portion 3 has a defect.

When the inspection is completed, the vacuum pump 7 and the air pump 8 are stopped, the fluid cylinder 11 is operated, and the second jig 6 is raised. At this time, the fluid cylinder 12 is operated to push down the lip portion 1 of the dust cover with the slide plate 6b (shown by a chain double-dashed line in FIG. 2), and the lip portion 1 is separated from the convex portion 16 of the second jig 6. . As a result, the dust cover 4 that has been inspected is always left on the first jig 5 side, which is effective in automating unloading and the like.

It should be noted that the embodiments described above are described for facilitating the understanding of the present invention, and not for limiting the present invention. Therefore, each element disclosed in the above-described embodiments is intended to include all design changes and equivalents within the technical scope of the present invention.

For example, the product accuracy of the lip portion 1 and the skirt portion 2 may be inspected by utilizing suction by the vacuum pump 7. That is, the vacuum pump 7 is provided with a verification means such as a pressure gauge, and the negative pressure changes when the lip portion 1 and the skirt portion 2 of the dust cover are attached to the first jig 5 and the second jig 6, respectively. The condition is observed by the pressure gauge. If there is a problem in forming the lip portion 1 or the skirt portion 2, the lip portion 1 or the skirt portion 2 is not properly adsorbed, so that a leakage occurs on the adsorption surface. Therefore, the degree of vacuum of the piping system of the vacuum pump 7 does not increase, and if this is detected by the pressure gauge, it can be applied to the inspection of the product accuracy of the lip portion and the skirt portion.

[0026]

In the leak inspection apparatus of the present invention, since the attachment portion of the inspection object is sucked by the negative pressure source and a positive pressure is applied to the inside of the inspection object to detect the presence or absence of leakage by the pressure change. It is also possible to find fine defects that cannot be visually detected. Moreover, since the leakage inspection is performed by the inspection object alone without incorporating it into the actual object, the information about the product defect can be immediately fed back to the process. Moreover, since the presence or absence of leakage is determined by the suction holding using the mounting portion of the object to be inspected and the detection of the pressure fluctuation, automation of the inspection process can be expected without complicated operations.

[Brief description of drawings]

FIG. 1 is a device configuration diagram showing a leak inspection device according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part for explaining a mounting state of an object to be inspected of the same embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lip part (mounting part) 1a ... Seal lip 2 ... Skirt part (mounting part) 2a ... Tsuba 3 ... Membrane part 4 ... Dust cover (inspection object) 5 ... 1st jig 6 ... 2nd jig 6a ... Main body 6b ... Slide plate 7 ... Vacuum pump (negative pressure source) 8 ... Air pump (positive pressure source) 9 ... Pressure gauge (verification means) 10 ... Ring 11, 12 ... Fluid cylinder 13 ... Convex portion 14 ... Recessed portion 15 ... through hole 16 ... convex portion 17 ... annular concave portion 18 ... positioning surface 19, 20, 21 ... through hole S ... space

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G01M 3/04 L

Claims (1)

[Claims] 1. A leak inspection apparatus for performing a leak inspection of an inspection object (4) having mounting portions (1, 2) and a film portion (3), wherein a first fixing member fitted to one of the mounting portions. A tool (5) and a second jig (6) fitted to the other of the mounting portions and provided so as to be able to move toward and away from the first jig relatively,
It is formed by a negative pressure source (7) connected to the first base and the second base and adsorbing the respective mounting portions, the first jig, the second jig, and the object to be inspected. A positive pressure source (8) for making the positive pressure in the space (S) and a verification means (9) for verifying the pressure state of the space made positive by the positive pressure source. Leak inspection device.