JPH0673548U - Magnetic fluid sealing device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a magnetic fluid seal device which has a good followability of a magnetic fluid and a good sealing property even when a shaft and a housing relatively reciprocate. A magnetic fluid seal device A for supporting a shaft 1 and a housing 2 concentrically and reciprocally relative to each other, and sealing a minute gap 15, 16 between the shaft 1 and the housing 2 with a magnetic fluid 5. Then, the cylinder 3 that interlocks with the shaft 1 is provided on the outer peripheral side of the housing 2, and the magnetic force sources 12, 32 and the magnetic pole pieces 13, 14, 33, in the direction of forming the magnetic circuit 6 in the shaft 1 and the cylinder 3.
34 is installed so that the magnetic fluid 5 can be reliably held by the strong magnetic fields of the minute gaps 15 and 16.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a sealing device that requires cleanliness, for example, a magnetic fluid sealing device applied to a reciprocating mechanism in a vacuum device.

[0002]

[Prior art]

 Conventionally, as a seal device applied to a reciprocating mechanism, for example, a squeeze packing 107 such as an O-ring as shown in FIG. 2 is generally used.

However, since it is a contact type, the sliding resistance is high, and the contact surface is abraded and the durability is poor. In particular, when it is used in a reciprocating mechanism such as a vacuum device, which requires cleanliness, there arises a problem that abrasion powder scatters into the device and contaminates the device.

Therefore, it is considered to use a non-contact type magnetic fluid seal device A'as shown in FIG.

This magnetic fluid sealing device A ′ is composed of a pair of annular magnetic pole pieces 123, 124 provided at a predetermined distance in the axial direction, and a magnetic force source interposed between the magnetic pole pieces 123, 124. And 122. The outer circumferences of the magnetic pole pieces 123 and 124 are fixed to the inner circumference of the housing 102, and annular minute gaps 115 and 116 are provided between the inner circumferences of the pole pieces 123 and 124 and the outer circumference of the shaft 101. The magnetic fluid 105 is enclosed in 115 and 116 for magnetic attraction.

That is, a loop-shaped magnetic circuit 106 that returns to the magnetic force source 122 through the magnetic force source 122, the one magnetic pole piece 123, the shaft 101, and the other magnetic pole piece 124 is formed, and is formed by the magnetic flux passing through the minute gaps 115 and 116. It holds the magnetic fluid 105.

[0007]

However, in the above-described conventional magnetic fluid seal device A ′, when the shaft 101 reciprocates due to the wettability of the magnetic fluid 105, the surface of the shaft 101 passes through the minute gaps 115 and 116. The magnetic fluid 105 adheres to the area, and the magnetic fluid 105 is reduced from the inside of the minute gaps 115 and 116, so that the sealing property is deteriorated.

Therefore, conventionally, the surface of the shaft 101 is subjected to an oil repellent treatment 108 so that the magnetic fluid 105 does not adhere to the surface of the shaft 101 even when the shaft 101 moves back and forth. However, even with this structure, the magnetic fluid 105 can be reliably retained. Difficult to do.

Although the magnetic force of the magnetic force source 122 can be increased to increase the holding force of the magnetic fluid 105, there is a limit.

The present invention was made in order to solve the above-mentioned problems of the prior art. The purpose of the present invention is to provide a good sealability for magnetic fluid even if the shaft and the housing relatively reciprocate. It is to provide a magnetic fluid seal device having good properties.

[0011]

[Means for Solving the Problems]

 In order to achieve the above object, in the present invention, a shaft and a housing are concentrically supported relative to each other so that they can reciprocate relative to each other, and a gap between the shaft and the housing is sealed with a magnetic fluid. In the fluid seal device, a magnetic force source is provided on each of the housing side and the shaft side, and the magnetic force source on the housing side and the magnetic force source on the shaft side are interlocked with each other.

[0012]

[Action]

 In the magnetic fluid seal device configured as described above, a magnetic force source is provided on the outer peripheral side of the housing and inside the shaft, and the magnetic force source on the outer peripheral side of the housing is linked with the magnetic force source provided inside the shaft. As a result, the magnetic fluid is always held by the magnetic fields formed by the two magnetic force sources even when the shaft and the housing reciprocate relative to each other.

[0013]

【Example】

 The present invention will be described below based on the illustrated embodiment.

FIG. 1 shows a magnetic fluid sealing device A according to an embodiment of the present invention.

The shaft 1 is attached to the first flange 9, and the annular housing 2 provided on the outer peripheral side of the shaft 1 is O-ringed to the annular second flange 10 having an inner diameter substantially the same as the inner diameter of the housing 2. It is attached via 7, the inside of which is the pressure fluid side to be sealed, and the magnetic fluid 5 is injected into the gap between the outer peripheral surface of the shaft 1 and the inner peripheral surface of the housing 2 for sealing. And the housing 2 are supported so that they can reciprocate relative to each other.

An annular cylinder 3 is further provided on the outer peripheral side of the housing 2 so that the diameter of the shaft 1 in the vicinity of the mounting portion of the first flange 9 is large and has a substantially T-shaped cross section, so that the cylinder 3 can be connected to the shaft 1. So that the outer diameter of the annular tube 3 is approximately the same as that of the annular tube 3, the tube 3 is supported and fixed to the shaft 1, and the inner and outer peripheral surfaces of the housing 2 and the open end 21 of the housing 2 are connected to the shaft 1. The shaft 1 and the cylinder 3 are reciprocally moved relative to each other via a bearing 4 between the outer peripheral surface of the housing 2 and the inner peripheral surface of the cylinder 3 so as to be covered by the annular cylinder 3. It is supported to be free.

That is, the shaft 1 and the ring-shaped cylinder 3 are interlocked with each other and reciprocate relative to the housing 2.

A pair of ring-shaped magnetic pole pieces 13, 14 are provided inside the shaft 1 at a predetermined distance in the axial direction, and are interposed between the magnetic pole pieces 13, 14 and have a U-shaped cross section in the axial direction. The magnetic force source 12 is provided so that The outer circumferences of the magnetic pole pieces 13 and 14 are fixed so as to be exposed as the outer peripheral surface of the shaft 1, and the annular minute gaps 15 and 16 are formed between the inner peripheral surface of the housing 102 and the outer peripheral surfaces of the magnetic pole pieces 13 and 14. Was set up.

In addition, the cylinder 3 is provided with a pair of axially spaced a predetermined distance so as to face the magnetic pole pieces 13 and 14 and the magnetic force source 12 provided inside the shaft 1 so as to form the magnetic circuit 6. The annular magnetic pole pieces 33 and 34 are provided, and the magnetic force source 32 is provided so as to be interposed between the magnetic pole pieces 33 and 34 and have a U-shaped cross section in the axial direction. The outer circumferences of the magnetic pole pieces 33, 34 and the magnetic power source 32 are fixed to the inner circumference of the cylinder 3.

A loop-shaped magnetic circuit 6 is formed between the magnetic pole pieces 13 and 14 and the magnetic force source 12 provided inside the shaft 1 and the magnetic pole pieces 33 and 34 and the magnetic force source 32 provided on the inner peripheral surface of the cylinder 3. Form.

Since the magnetic circuit 6 has magnetic sources 12 and 32 on both sides of the minute gaps 15 and 16, respectively, the magnetic source 122 is provided only on the side of the conventional housing 102, and the magnetic circuit 106 is formed. In comparison, leakage of magnetic field lines can be prevented and a very strong magnetic field can be obtained.

Therefore, due to the strong magnetic field of the magnetic circuit 6, the magnetic fluid 5 injected into the annular minute gaps 15 and 16 does not adhere to the passage area on the surface of the shaft 1 and the minute gap 15 is not formed. , 16 to follow the reciprocating motion of the shaft 1 and the annular cylinder 3 and to reliably reciprocate.

With such a configuration, the injected magnetic fluid 5 is securely held by the magnetic circuit 6, and even if the shaft 1 and the annular tube 3 are interlocked with each other and reciprocally moved with respect to the housing 2. The magnetic circuit 6 formed by the shaft 1 and the ring-shaped cylinder 3 also reciprocates while holding the magnetic fluid 5, so that the magnetic fluid 5 can follow well, the sealing function is improved, and cleanliness is required. The magnetic fluid sealing device can be used even in a vacuum device.

[0024]

[Effect of device]

 The present invention has the above-described configuration and operation, and the magnetic fluid that seals the gap between the shaft and the housing when the two magnetic sources provided on the shaft and the housing are interlocked. A magnetic fluid seal device that is securely held by the strong suction force of the magnetic force source, has good followability of the magnetic fluid even when it reciprocates relatively, and can be used even in a vacuum device where cleanliness is required, with a good sealing property. Can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of a magnetic fluid seal device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a conventional sealing device.

FIG. 3 is a cross-sectional view of a main part of a conventional magnetic fluid seal device.

[Explanation of symbols]

 A, A'Magnetic fluid seal device 1,101 Shaft 2,102 Housing 3 Tube (interlocking means) 4 Bearing 5,105 Magnetic fluid 6,106 Magnetic circuit 7,107 O-ring 9 First flange 10 Second flange 12 Shaft 1 Magnetic source 13 of 14, Axis 1 magnetic pole piece 15, 16, 115, 116 Micro gap 21 End part of housing 32 Magnetic source 33 of cylinder 3 33 34 Magnetic pole piece of cylinder 3 108 Oil repellent 122 Magnetic source 123, 124 Pole piece

Claims (1)

[Scope of utility model registration request] 1. A magnetic fluid seal device which supports a shaft and a housing concentrically and relatively reciprocally relative to each other, and seals a gap between the shaft and the housing with a magnetic fluid. A magnetic fluid sealing device, wherein a magnetic force source is provided on each of the shaft sides, and the magnetic force source on the housing side and the magnetic force source on the shaft side are interlocked with each other.