JP3022692B2 - Leak inspection 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 leak inspection apparatus for performing a leak inspection based on fluid loss, and is used in powder metallurgy.

[0002]

2. Description of the Related Art A typical manufacturing process in powder metallurgy is as follows.
The mixing step, the forming step, the sintering step, the straightening step, the processing or surface treatment step, and the inspection step are performed in this order. In the mixing step, raw material powder such as a metal is mixed. In the forming step, the raw material powder is compressed and formed by a powder forming press. In the sintering step, the green compact after the forming step is heated and sintered. In the straightening step, the sintered body after the sintering step is recompressed by a straightening press to have a predetermined shape and dimensions. In the processing or surface treatment process, quenching, cutting, polishing, and the like are performed.

As described above, conventionally, the inspection process has been performed as a final process, but this has the following problems. First, even for a defective product in a certain process, all the intermediate processes up to the subsequent inspection process are performed. However, this is wasteful, and the processing cost of the intermediate process is unnecessary. Further, the lead time required for the inspection process is wasted.

Incidentally, there is a leak inspection as one of the inspection processes. Here, an example of a conventional leak inspection apparatus will be described with reference to FIG. Reference numeral 1 denotes a sintered body part (hereinafter, referred to as a work) which is an inspection object. The work 1 is a piston part for a shock absorber, has a cylindrical shape, and has an end face part 2 at an upper part in the drawing. An opening 3 is provided at the center of the end face portion 2. An annular projection 4 is formed on the end face 2 surrounding the opening 3. In the regular shape, the lower surface a and the upper surface b of the work 1 are both flat and parallel to each other. The leak inspection apparatus has a metal lower valve 6 and a metal upper valve 7 which is located above and lowers the lower valve 6. The upper surface of the lower valve 6 and the lower surface of the upper valve 7 are both flat and horizontal. And the upper valve 7
Is formed with a spout 8 opening to the lower surface thereof.
The jet port 8 jets air. And
In the leak inspection, after the work 1 is carried onto the lower valve 6, the upper valve 7 descends, and the lower surface of the upper valve 7 contacts the upper end surface of the work 1. More specifically, the distal end surface of the annular projection 4 of the work 1 surrounds the ejection port 8 and contacts the lower surface of the upper valve 7. Next, air is blown out from the outlet 8. At this time, the air pressure is detected, and if this pressure falls below a predetermined value, the work 1
The work 1 is determined to be defective, assuming that there is an air leak due to damage to the work.

[0005]

As described above, in the production process of powder metallurgy, there has been a problem that the inspection process has conventionally been the final process, so that there is much waste.

Therefore, for example, it is conceivable to attach an in-line type leak inspection device to the straightening press and perform a leak inspection of the work 1 immediately before the straightening process. However,
Before the straightening process, the lower end 1a and the upper end 1b of the work 1
Burrs or protrusions of about 0.03 to 0.1 mm are generated. At the same time, the flatness and parallelism of the lower end 1a and the upper end 1b of the work 1 are also deteriorated. The flatness and parallelism are originally improved by straightening, and burrs are also removed by straightening and subsequent processing or surface treatment. However, before the correction process, the presence of the burrs or the poor flatness and parallelism may cause a problem that if a leak test is performed in this state, the work 1 that can be a good product is erroneously determined as a defective product. That is, if the burrs are within the allowable range or the flatness or the parallelism before the straightening process, but the burrs are large to some extent, or the flatness or the parallelism becomes a certain value or more, the work 1 which can be a non-defective product. Is erroneously determined to be defective.

[0007] The present invention is intended to solve such a problem, and the presence of burrs or poor flatness or parallelism that can be improved in a subsequent process, such as immediately before a straightening process in powder metallurgy, is reduced. It is an object of the present invention to provide a leak inspection device capable of accurately performing a leak inspection without erroneously determining a bonded part as a defective product.

[0008]

In order to achieve the above object, the present invention comprises a pair of valves which approach and move away from each other and sandwich a sintered part which is an object to be inspected. In a leak inspection apparatus having an ejection port for ejecting a fluid toward a body part, the valve includes a base, a valve body supported by the base, a valve body interposed between the base and the valve body, and a valve body with respect to the base. And a second elastic member provided on the valve body and in contact with the sintered body component.

[0009]

In the leak inspection apparatus of the present invention, at the time of inspection, first, a pair of valves are brought close to each other, and a sintered body part to be inspected is sandwiched by these valves. In this state, a fluid is ejected from the ejection port of one of the valves toward the sintered component. Here, if there is leakage of the fluid, for example, the pressure of the fluid decreases on the one valve side, so that the quality of the sintered body component is determined. By the way, for example, when an inspection is performed before the correction process of powder metallurgy, even a sintered part that can be a good product originally has burrs or poor flatness or parallelism, but the valve is attached to the valve body. Since the provided second elastic material is in contact with the sintered component, the second elastic material surely comes into close contact with the sintered component even if there is a burr within an allowable range or poor flatness. . With this,
Even if the degree of parallelism falls within the allowable range, the first elastic member is interposed between the valve body and the base, and the valve body can be tilted in any direction with respect to the base. The second elastic material surely comes in close contact with the sintered component. Thus,
It is possible to prevent the sintered part from being determined as a defective product even if there are burrs within the allowable range or poor flatness or parallelism. That is, it is possible to prevent a sintered body component that can be a good product from being determined as a defective product.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a leak inspection apparatus according to the present invention. Since the sintered body part (work) 1 to be inspected is the piston part for the shock absorber shown in FIG. 2 described above, the corresponding parts are denoted by the same reference numerals and description thereof will be omitted.

The present inspection apparatus includes a lower valve 11 and an upper valve 12 that sandwich the work 1 from above and below in a press-fit state.
The lower valve 11 is a disk-shaped metal valve body on a base 16.
17 support. The base 16 is formed by fixing a second substrate 19 on a first substrate 18 with bolts. Second
The substrate 19 has a through hole 20 through which the valve body 17 is fitted with a slight gap.
An inward flange 21 is formed on the upper part of the peripheral surface.
On the other hand, a flange 22 is formed in the middle part of the peripheral surface of the valve body 17, and the inward flange 21 of the second substrate 19 is opposed to the flange 22 from above from above, so that the valve The main body 17 is retained. A rubber O-ring 23 as a first elastic material is interposed between the lower surface of the flange 22 and the upper surface of the first substrate 18. Due to the O-ring 23, a small gap C1 of about 0.1 mm is generated between the upper surface of the first substrate 18 and the lower surface of the valve body 17 facing the first substrate 18 in a natural state. , Can be slightly tilted in any direction with respect to the base 16. Further, a flat elastic plate 24 as a second elastic material is attached to the upper surface of the valve body 17. The elastic plate 24 is made of a urethane material, which is a rubber.
It is located lower with a height difference C2 of about 0.1 mm.

The upper valve 12 also has a disk-shaped metal valve body 27 supported on a base 26. The base
Reference numeral denotes a holding frame 29 fixed to the lower surface of the substrate by bolts. The holding frame 29 has the valve body 27 fitted therein with a slight gap.
Are formed at the lower portion of the inner peripheral surface. This inward flange 30
, From below, contacts the periphery of a flat elastic plate 31 as a second elastic material attached to the lower surface of the valve main body 27 to prevent the valve main body 27 from coming off with respect to the base 26. Also,
An upward step surface 32 formed on the upper peripheral portion of the valve body 27
A rubber O-ring 33 as a first elastic material is interposed between the O-ring 33 and the lower surface of the substrate 28. Due to the O-ring 33, a minute gap C3 of about 0.1 mm is generated between the lower surface of the substrate 28 and the upper surface of the valve body 27 facing the substrate 28 in the natural state. , Can be slightly tilted in any direction. Further, the elastic plate 31
Is made of a urethane material which is a rubber, and has a lower surface which is horizontal in a natural state. The substrate 28 of the upper valve 12 is connected to a rod cylinder 37 for driving up and down via a floating joint 36, so that the upper valve 12 moves up and down above the lower valve 11. The upper valve 12 has an air inlet 38 formed on a side surface of the valve body 27, and an outlet 39 communicating with the air inlet 38 and opening to the center of the lower surface of the elastic plate 31. I have. Although not shown in the air inlet 38,
An air circuit including an air source and a pressure gauge is connected.

The leak inspection apparatus is used in powder metallurgy, and is mounted on a straightening press in an inline manner.

Next, the operation of the above configuration will be described. The leak inspection is performed in the powder metallurgy manufacturing process immediately before the straightening process after the sintering process. First, the work 1 is laterally moved on the substrate 18 in the direction indicated by the arrow A by the resin transport plate (not shown), and is placed on the center of the lower valve 11 on the elastic plate 24. Next, the upper valve 12 descends together with the rod cylinder 37 as shown by the arrow B, and the elastic plate 31 of the upper valve 12 contacts the upper surface of the work 1 as shown by the chain line. In addition, the tip of the annular projection 4 of the work 1 surrounds the ejection port 39 and contacts the lower surface of the elastic plate 31. Thus, the work 1 is sandwiched between the elastic plates 24 and 31 of the two valves 11 and 12 in a press-fit state. In this state, air pressure is applied to the air inlet 38 to blow air from the outlet 39 of the upper valve 12 into the work 1. At this time, the air pressure is detected, and if this pressure falls below a predetermined value, the work 1
The work 1 is determined to be defective, assuming that there is an air leak due to damage to the work. On the other hand, if the air pressure does not fall below the predetermined value, the work 1 is determined to be non-defective. After the inspection, after the upper valve 12 is raised together with the rod cylinder 37, the inspected work 1 is carried out from above the elastic plate 24 of the lower valve 11 in the direction indicated by the arrow A, and the next work 1 is It is carried on and the inspection is repeated. The inspection is performed at a rate of, for example, one every 0.6 seconds.
0.02 kg. Then, the work 1 determined to be defective is removed, and the work 1 determined to be non-defective is sent to a straightening press and straightened.

By the way, before the straightening step, even if the work 1 can be a non-defective product after straightening, processing or surface treatment, burrs may be generated at the lower end or the upper end.
The lower surface and the upper surface may have poor flatness or mutual parallelism. On the other hand, in the lower valve 11 and the upper valve 12, since the elastic plates 24 and 31 made of urethane material are pressed against the lower surface and the upper surface of the work 1, respectively, the existence of burrs within the allowable range and the flatness of the lower surface and the upper surface are considered. However, the elastic plates 24 and 31 are securely adhered to the lower surface and the upper surface of the work 1 without any gap. At the same time, rubber O-rings 23 and 33 are interposed between the valve bodies 17 and 27 and the bases 16 and 26 that support the valve bodies 17, 27 even if the lower surface and the upper surface have poor parallelism within the allowable range. And the valve bodies 17, 27 slightly tilt in any direction with respect to the horizontal plane,
The elastic plates 24 and 31 securely adhere to the lower and upper surfaces of the work 1 without any gap. In this way, even if there are burrs within the allowable range or poor flatness or parallelism, the valve
By being able to respond to 11 and 12, it is possible to prevent the work 1 from being determined as a defective product.

As described above, according to the configuration of the above embodiment, the burrs and deformations which can be improved in the subsequent steps are reduced.
Despite performing a leak test before the straightening process in
It is possible to prevent the work 1 that can be a good product from being determined as a defective product. That is, even before the correction process, the leak test can be accurately performed. By performing the leak inspection before the correction process, there is no waste in performing the processes after the correction process on the defective product, and the waste of the processing cost can be reduced. In addition, since the leak inspection device is mounted on the straightening press in an in-line manner, waste of lead time required for the inspection process can be reduced. In addition, conventional automatic straightening devices,
In particular, since the transport unit can be used as it is, the production cost can be reduced. In the valves 11 and 12, the valve body
The O-rings 23 and 33 are used to enable the tilting of the members 17 and 27. However, the O-rings 23 and 33 can increase the stability as means for enabling the tilting.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made. First, the sintered body component to be inspected is not limited to the one in the embodiment. And, for example, an orifice (concave groove)
For the workpieces marked with, the leak inspection can be performed immediately before, and the target of the leak inspection can be greatly expanded as compared with the related art. In the above embodiment, the valve bodies 17 and 27 are both tiltably supported on the bases 16 and 26 via the O-rings 23 and 33 in both the lower valve 11 and the upper valve 12. May be only one of the lower valve and the upper valve.

[0018]

According to the present invention, in a leak inspection apparatus in which a sintered body part is sandwiched between a pair of valves and a fluid is ejected from one valve toward the sintered body part, the valve has a first base. By supporting the valve body via the elastic material, the valve body can be tilted in an arbitrary direction, and the valve body is provided with the second elastic material which is in contact with the sintered body component. Even just before the process, even if the presence of burrs that can be improved in the subsequent process or poor flatness or parallelism is present in the sintered part, the leak inspection can be accurately performed without erroneously determining this as a defective product. . Further, since the leak inspection can be performed before the correction process, it is possible to eliminate the waste of performing the processes after the correction process on the defective product. At the same time, it is possible to perform a leak test even on a sintered body part having an orifice formed on an end face in a straightening process, and the number of products subjected to the leak test is increased.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a leak inspection apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing an example of a conventional leak inspection device.

[Explanation of symbols]

 Reference Signs List 1 work (sintered body part) 11 lower valve 12 upper valve 16 base 17 valve body 23 O-ring (first elastic material) 24 elastic plate (second elastic material) 26 base 27 valve body 31 elastic plate (second Elastic material) 33 O-ring (first elastic material) 39 Spout

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01M 3/26 G01M 3/04

Claims (1)

(57) [Claims] 1. A leak inspection apparatus comprising: a pair of valves approaching and separating from each other and sandwiching a sintered body component to be inspected, and one of the valves having an ejection port for ejecting a fluid toward the sintered body component. Wherein the valve comprises a base, a valve body supported by the base, a first elastic member interposed between the base and the valve body and capable of tilting the valve body relative to the base in an arbitrary direction; A second elastic member provided on the valve body and in contact with the sintered body part.