JPH0650837A - Apparatus for inspecting air leak - Google Patents

Abstract

PURPOSE:To ensure sealing and to conduct precise inspection even when there is some nonuniformity in a state of joining of an object of inspection to a joining end face part, by a method wherein a connecting member sending out compressed air is pressed on and joined to the object of inspection by a pressing member. CONSTITUTION:When a spindle motor 18, an object of inspection, is set on a receiving member 11 of a holding means 20 and a switch 5 of a control box 3 is pushed, compressed air is sent out to an air cylinder 14 from a compressor 1 through a sending-out passage 15. Then a cylinder rod 19 lowers and presses the motor 18. Thereby the motor 18 is fixed to the holding means 20 and joined surely to a connecting member 17. When a switch 4 of the control box 3 is pushed subsequently, the compressed air from the compressor 1 is sent out to the connecting member 17 through a sending-out passage 16 and sent into the motor 18. Thereafter a computer 8 monitors an air pressure detected by a pressure gage 2 and computes the degree of lowering of the air pressure, and when a value of change in relation to a prescribed value is large, this is judged as an air leak fault.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air leak inspection device for inspecting an air leak of an object to be inspected by sending compressed air to the object to be inspected and detecting the atmospheric pressure of the sent air.

[0002]

2. Description of the Related Art For example, a spindle motor used in a magnetic disk drive or the like is equipped with a magnetic fluid seal in order to prevent unclean air from flowing into the disk chamber. When checking the sealing function of such a spindle motor, an air leak inspection device is used. When inspecting a fixed shaft type spindle motor, for example, the air leakage inspection device connects a connection pipe having a size substantially equal to the shaft diameter to the through hole of the shaft communicating with the inside of the motor,
Compressed air is sent to this connecting pipe, and the presence or absence of air leakage is inspected by the change in air pressure.

[0003]

However, the connecting surface of the connecting pipe, and particularly the end surface portion of the through hole of the shaft, is not necessarily machined with high precision, and the spindle motor is used as an air leakage inspection device. On the other hand, they are not necessarily positioned and connected. That is, these often have a predetermined variation. Therefore, when the connection between the through hole of the shaft and the connecting pipe is not good, air leaks from this joint portion, and it is impossible to inspect the spindle motor as the inspection object for accurate air leakage.

The present invention has been made in view of the above problems existing in the prior art. The problem is that the bonding state with the connection end face portion of the object to be inspected is slightly varied. Even if there is, there is a need to provide an air leakage inspection device capable of reliably sealing the joint portion and realizing an accurate air leakage inspection.

[0005]

In order to achieve the above-mentioned object, an air leakage inspection apparatus of the present invention comprises a holding means for holding and fixing the inspected object having a tubular detection hole, and the holding means. An air leakage inspection device for inspecting the object to be inspected for air leakage, comprising: pressure feeding means for feeding compressed air to the pressure feeding means; and pressure detection means provided in communication with the pressure feeding means; Is a fixing member, a connection member that is supported so as to be movable relative to the fixing member, and that is joined to the detection hole of the inspection object and sends out compressed air, and presses the inspection object. And a pressing member for joining the connecting member; and the connecting end portion of the connecting member,
It has a taper shape that expands in the opening direction from the small diameter portion to the large diameter portion over the entire circumference, an elastic annular member is externally fitted to the small diameter portion of the connecting end, and the outer edge portion of the elastic annular member is held by the fixing member. When the pressing member presses the inspection object, the detection hole of the inspection object is joined to the connection end portion of the connection member, and the connection member retreats with respect to the fixing member. Provided is an air leakage inspection device, wherein an elastic annular member moves from a small diameter portion of a connection end portion to a large diameter portion to seal a joint between the detection hole and the connection end portion. .

[0006]

When the pressing member presses the inspection object when the inspection object is inspected, the detection hole of the inspection object is joined to the connecting member,
Accordingly, the connecting member also moves in the pressing direction. In this case, the connecting member moves backward with respect to the fixed member. On the other hand, the elastic annular member is fitted onto the connecting end of the connecting member, and the outer edge of the elastic annular member is held by the fixing member. Therefore, due to the backward movement of the connecting member, the elastic annular member moves from the small-diameter portion to the large-diameter portion of the connecting end while being gripped (laddered) by the fixing member. An elastic annular member is externally fitted to the joint between the detection hole of the object to be inspected and the connection end. The joint portion is sealed by the outer fitting of the elastic annular member.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the air leakage inspection apparatus according to the present invention will be described with reference to FIGS. Figure 1
It is a schematic diagram showing the whole air leakage inspection device of the present invention.
In FIG. 1, this device is for inspecting a spindle motor having a magnetic fluid seal for air leakage. The member 18 is a spindle motor as an inspection object. The spindle motor 18 is attached to the holding means 20. The holding means 20 is the spindle motor 18
Receiving member 11 for directly receiving and holding
And a connecting member 17 which is provided inside the fixing member 10 and is connected to the spindle motor 18, and which is an air pressure member for pressing the spindle motor 18 from the top to the bottom of the drawing. It is composed of a cylinder 14. The member 1 is a compressor which is a pressure-feeding means, and the compressed air generated by this is sent out to the connecting member 17 of the holding means 20 through the delivery path 16. Similarly, the compressed air is sent out to the air cylinder 14 via the sending passage 15. The air cylinder 14 is supported by the arms 13 of the columns 12 that are erected on the fixing member 10. Then, the cylinder rod 19 is supported so as to be vertically movable by sending out the compressed air.

The member 2 is a pressure gauge as a pressure detecting means provided integrally with the compressor 1 and in communication with the delivery passage 16 of the compressor 1. The member 3 is a control box and has a switch 5 and a switch 4,
It is connected to the pressure gauge 2 via a lead wire 6. Further, the pressure gauge 2 is connected to a microcomputer 8 via a lead wire 7. When the spindle motor 18 is placed on the receiving member 11 and the switch 5 of the control box 3 is pressed,
Compressed air is sent from the compressor 1 to the air cylinder 14 via the sending path 15. Then, the cylinder rod 19 descends in the downward direction of the figure and presses the spindle motor 18. As a result, the spindle motor 18 is held and fixed to the holding means 20, and is securely joined to the connecting member 17. Next, when the switch 4 of the control box 3 is pressed, the compressed air is sent out from the compressor 1 through the delivery passage 16 to the connecting member 17 inside the fixing member 10.
At this time, the compressed air is sent from the connecting member 17 into the spindle motor 18 for a certain period of time. After sending out the compressed air, the microcomputer 8 monitors the air pressure detected by the pressure gauge 2 for a certain period of time, calculates the degree of decrease thereof, and judges that the air leakage is defective if the change value is large with respect to a predetermined value. To do.

Next, the spindle motor 18 holds the holding means 2.
The state of being attached to 0 will be described in more detail with reference to FIGS. 2 to 4. FIG. 2 is an enlarged cross-sectional view of the holding means 20, and FIG. 3 is an enlarged cross-sectional view of a part of the holding means 20. 2 and 3, in the fixing member 10, the upper base 69 and the lower base 35 have the male screw 3
It is fixed integrally by 7. An O-ring 36 is provided on these joint surfaces 70 for both vibration prevention and sealing. The central portions of the upper base 69 and the lower base 35 respectively corresponding to each other are integrally provided with a cylindrical portion 29 and a cylindrical portion 71, which have a cylindrical shape. The male screw 34 is provided on the annular collar portion 38 of the upper base 69 at three positions at equal angles of 120 degrees in the circumferential direction. (One is drawn on the right side in FIG. 2.) A spring 33 is fitted into the male screw 34, and the lower end 2 of the flange portion of the receiving member 11 is inserted through the spring 33.
It is fixed to 7). Also, the cylindrical portion 29 of the upper base 69
A sleeve bearing is provided between the outer peripheral surface 30 of the base member and the inner peripheral surface 28 of the receiving member 11, so that the receiving member 11 is elastically urged upward with respect to the upper base 69. It is urged and movable in the vertical direction in the figure. The receiving member 11 has a hole 74 provided coaxially with the axis 73, and the hub collar 24 of the spindle motor 18 is positioned and placed in the annular groove 25 at the peripheral edge thereof. .

A slide ball bearing 51 is attached to the inner peripheral surface 49 of the cylindrical portion 29 of the upper base 69, and the connecting member 17 is supported movably in the up and down direction in the figure via the slide ball bearing 51. The lower side of the connecting member 17 in the drawing, the cylindrical end portion 41,
The bottom surface is closed, and a spring 43 is attached to the outer peripheral surface 50. One end of the spring 43 is connected to a C ring provided on a part of the outer peripheral surface 50, and the other end is in contact with the bottom surface portion 72 of the lower base 35. Therefore, the connecting member 17
Is elastically urged upward in the drawing by a spring 43, and is movably provided in the vertical direction in the drawing with respect to the fixing member 10 including the upper and lower bases 69 and 35. Connection member 1
A hole 44 is provided at substantially the center of 7, and is connected to the hole 45 of the cylindrical portion 71 of the lower base 35 by the delivery passage 46, and further by the delivery passage 16, the compressor 1 (see FIG. 1).
(Shown in).

The connecting member 17 has a hole portion 63 penetrating therethrough, and is provided coaxially with the axis 73.
A connecting portion 65 is integrally fixed to the upper end of the connecting member 17 in the figure. That is, a male screw is provided on the outer peripheral surface of the connection lower portion 57, and a female screw is provided on the inner peripheral surface 40 of the connection member 17 correspondingly, and these are screwed together and integrally fixed. The connection end portion 56 located at the upper end of the connection portion 65 has
A large diameter portion 59 and a small diameter portion 58 are formed with a joint surface 54 that is joined to the detection hole 31 (joint surface 53) of the spindle motor 18 as its upper end surface. That is, the connection end portion 56 has a taper shape that spreads in the opening direction over the entire circumference, and has a large diameter portion 59.
And a small diameter portion 58. The opening 60 (the portion 75 in the illustrated example) of the cylindrical portion 29 (of the upper base 69) corresponding to the connecting end portion 56 is formed coaxially with the axis 73, and the inner diameter dimension thereof is the outer diameter of the large diameter portion 59. Smaller size, small diameter part 58
It is set to be larger than the outer diameter of. A rubber O-ring, which is an elastic annular member, is fitted between the stepped portion 62 of the opening 60 and the small diameter portion 58.

As shown in FIG. 3, the spindle motor 18
The joint surface 53 of the detection hole 31 of the
The state of joining to No. 4 will be further described with reference to FIG. The air cylinder 14 shown in FIG. 2 is operated, and the cylinder rod 19 moves downward along the axis 73.
Then, the tip end portion 21 of the cylinder rod 19 presses the shaft end portion 23 of the spindle motor 18, and accordingly, the receiving member 11 descends (against the elastic bias of the spring 33). Then, as shown in FIG. 4A, the lower end portion of the shaft 22 of the spindle motor 18 and the detection hole 31 (joint surface 53) come into contact with the joint surface 54 of the connection end portion 56. Further, when the cylinder rod 19 descends, the connecting member 17 (including the integrally connected connecting end portion 56) descends against the elastic bias of the spring 43. Then, the O-ring 55 externally fitted to the connection end portion 56 moves according to the downward movement of the connection end portion 56 in the drawing.
While being handled (laddered) by the stepped portion 62, the connection end portion 56 moves from the small diameter portion 58 to the large diameter portion 59.

As shown in FIG. 4B, the O-ring 55 is fitted on the joint portion 68, and the diameter of the O-ring 55 is greatly expanded. Therefore, the contracting force of the O-ring 55 causes the outer peripheral portion of the joint portion 68 to more firmly adhere. Thus, the compressed air communicating with the compressor 1 passes through the delivery passage 16, the internal space 47 of the connecting member 17, and the hole 64 of the shaft 22 to communicate with the internal space 32 of the spindle motor 18. Therefore, even if the joining surface 53 of the detection hole 31 of the spindle motor 18 and the joining surface 54 of the connecting end portion 56 are not in a very good joined state, it is possible to reliably seal them. Therefore, air leakage does not occur even when the positioning accuracy with which the object to be inspected is mounted or the bonding surface processing accuracy is not so good. The large-diameter portion 5 at the connection end portion 56
According to the present embodiment, the taper shape formed by 9 and the small diameter portion 58 has the gradient set as follows. That is, the angle sandwiched between the contour line defined on the axis 73 of the tapered surface and the axis 73 is 40 degrees to 4 degrees.
5 degrees is desirable. Of course, it goes without saying that the O-ring can be freely selected depending on the material and elasticity (contraction) rate.

After the air leak inspection for a predetermined time is completed,
When the cylinder rod 19 of the air cylinder 14 rises, the connecting member 17 and the receiving member 11 rise with respect to the fixing member 10 due to the elastic force of the spring 43 and the spring 33. At that time, the O-ring 55 of the connection end 56
Moves back from the large diameter portion 59 to the small diameter portion 58 due to the contracting force. Therefore, even when a large number of inspection objects are inspected in a short time, reliable work can be performed and highly reliable inspection can be performed.

As described above, design changes and modifications can be freely made without departing from the spirit of the present invention.

[0016]

Since the air leakage inspection apparatus of the present invention has the above-mentioned structure, it has the following effects. That is, even if there is variation in the shape or processing accuracy of the joint surface of the inspection hole of the inspection object, or if there is variation in the positioning at the time of joining, air leakage does not occur at the joint portion. Therefore, an air leak inspection device capable of performing an air leak inspection with high workability can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an entire air leakage inspection device according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the air leakage inspection apparatus according to the embodiment of the present invention, which is an enlarged view of a part of FIG. 1.

FIG. 3 is an enlarged sectional view of an essential part showing an enlarged part of FIG.

FIG. 4 is an enlarged sectional view of an essential part showing the operation of the air leakage inspection device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor (pressure feeding means) 2 Pressure gauge (pressure detection means) 3 Control box 8 Microcomputer 10 Fixing member 18 Spindle motor (inspection object) 20 Holding means 31 Detection hole 55 O-ring (elastic annular member) 56 Connection end 58 Small diameter part 59 Large diameter part

Claims (1)

[Claims] 1. A holding means having a tubular detection hole for holding and fixing the object to be inspected, a pressure feeding means for feeding compressed air to the holding means, and a pressure detection provided in communication with the pressure feeding means. An air leakage inspection device for inspecting the object to be inspected for air leakage, wherein the holding means is supported by a fixing member and relatively movable with respect to the fixing member,
A connection member that joins the detection hole of the inspection object and sends out compressed air, and a pressing member that presses the inspection object and joins the detection hole and the connection member, the connection end of the connection member The portion has a taper shape that spreads in the opening direction from the small diameter portion to the large diameter portion over the entire circumference, and an elastic annular member is externally fitted to the small diameter portion of the connection end, and the outer edge portion of the elastic annular member is fixed to the fixed portion. When the pressing member presses the inspection object, the detection hole of the inspection object is joined to the connection end of the connection member, and the connection member moves backward with respect to the fixed member. Then, the elastic annular member moves from the small diameter portion of the connection end portion to the large diameter portion to seal the joint portion between the detection hole and the connection end portion.