Magnetic liquid sealing device

Patent metadata

Field	Value
Publication number	US-11466780-B2
Application number	US-202117212027-A
Country	US
Kind code	B2
Filing date	Mar 25, 2021
Priority date	Jan 13, 2021
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

A magnetic liquid sealing device is provided. The magnetic liquid sealing device includes a housing, a rotating shaft, a pole shoe, a permanent magnet, and a first sealing ring. The rotating shaft is provided with an annular first stop portion, the pole shoe has a first end face and a second end face opposite to each other in an axial direction of the rotating shaft, and the permanent magnet is fitted over the rotating shaft. The first sealing ring is fitted over the rotating shaft, and includes a first part and a second part. The first part is sealedly fitted with at least one of the first end face and an inner peripheral surface of the housing, and an inner end of the second part is a first free end movably arranged along the axial direction of the rotating shaft.

First claim

The invention claimed is:

1. A magnetic liquid sealing device, comprising:
a housing defining a cavity therein;
a rotating shaft rotatably arranged in the cavity and provided with an annular first stop portion and an annular second stop portion, the first stop portion and the second stop portion being spaced apart along an axial direction of the rotating shaft;
a first pole shoe and a second pole shoe fitted over the rotating shaft, the first pole shoe and the second pole shoe being spaced apart along the axial direction of the rotating shaft, the first pole shoe having a first end face and the second pole shoe having a second end face opposite to each other in the axial direction of the rotating shaft, the first end face being arranged between the first stop portion and the second end face in the axial direction of the rotating shaft, the second end face being arranged between the second stop portion and the first end face in the axial direction of the rotating shaft, and a magnetic fluid being filled between the first pole shoe and the rotating shaft and between the second pole shoe and the rotating shaft;
a permanent magnet fitted over the rotating shaft, the permanent magnet being arranged between the first pole shoe and the second pole shoe in the axial direction of the rotating shaft;
a first sealing ring fitted over the rotating shaft, the first sealing ring comprising a first part and a second part, the first part being connected to or integrated with the second part, the first part being arranged at an outer side of the second part in an inner-outer direction, the first part being sealedly fitted with at least one of the first end face and an inner peripheral surface of the housing, the second part having an inner end and an outer end opposite to each other in the inner-outer direction, the inner end of the second part being a first free end movably arranged along the axial direction of the rotating shaft, the first free end having a first initial position in which the first free end is spaced apart from the first stop portion and adjacent to the first stop portion in the axial direction of the rotating shaft, and a first sealing position in which the first free end sealedly abuts against the first stop portion, wherein the first free end is movable between the first initial position and the first sealing position based on a pressure difference between a pressure at the first end face and an external pressure of the first sealing ring; and
a second sealing ring fitted over the rotating shaft, the second sealing ring comprising a third part and a fourth part, the third part being connected to or integrated with the fourth part, the third part being arranged at an outer side of the fourth part in the inner-outer direction, the third part being sealedly fitted with at least one of the second end face and the inner peripheral surface of the housing, the fourth part having an inner end and an outer end opposite to each other in the inner-outer direction, the inner end of the fourth part being a second free end movably arranged along the axial direction of the rotating shaft, the second free end having a second initial position in which the second free end is spaced apart from the second stop portion and adjacent to the second stop portion in the axial direction of the rotating shaft, and a second sealing position in which the second free end sealedly abuts against the second stop portion, wherein the second free end is movable between the second initial position and the second sealing position based on a pressure difference between a pressure at the second end face and an external pressure of the second sealing ring.

2. The magnetic liquid sealing device according to claim 1 , wherein the first free end is arranged between the first stop portion and the first end face in the axial direction of the rotating shaft, and the second part is configured to be elastically deformed such that the first free end moves along the axial direction of the rotating shaft, and
the second free end is arranged between the second stop portion and the second end face in the axial direction of the rotating shaft, and the fourth part is configured to be elastically deformed such that the second free end moves along the axial direction of the rotating shaft.

3. The magnetic liquid sealing device according to claim 2 , wherein a cross section of the second part comprises a first section portion and a second section portion arranged on both radial sides of the rotating shaft, and each of the first section portion and the second section portion has a substantial C shape, and
a cross section of the fourth part comprises a third section portion and a fourth section portion arranged on both radial sides of the rotating shaft, and each of the third section portion and the fourth section portion has a substantial C shape.

4. The magnetic liquid sealing device according to claim 2 , wherein the first part is provided with a first mounting groove, and the outer end of the second part is arranged in the first mounting groove with an interference fit,
the third part is provided with a second mounting groove, and the outer end of the fourth part is arranged in the second mounting groove with an interference fit.

5. The magnetic liquid sealing device according to claim 2 , further comprising a first elastic member configured to exert an elastic force facing away from the first end face to the first free end and a second elastic member configured to exert an elastic force facing away from the second end face to the second free end.

6. The magnetic liquid sealing device according to claim 5 , wherein each of the first elastic member and the second elastic member is a compression spring, the first elastic member is arranged between the first end face and the first free end, and the second elastic member is arranged between the second end face and the second free end.

7. The magnetic liquid sealing device according to claim 6 , further comprising a first sealing gasket and a second sealing gasket, an outer peripheral surface of the first pole shoe being provided with a first annular groove, the first sealing gasket being fixedly mounted in the first annular groove, an outer peripheral surface of the first sealing gasket being fitted with the inner peripheral surface of the housing, an outer peripheral surface of the second pole shoe being provided with a second annular groove, the second sealing gasket being fixedly mounted in the second annular groove, and an outer peripheral surface of the second sealing gasket being fitted with the inner peripheral surface of the housing.

Assignees

• Univ Tsinghua

Inventors

• Li Decai
• Ren Sijie
• Li Yingsong
• Han Pengdong

Classifications

• F16J15/3456

  without external means for pressing the ring against the face, e.g. slip-ring with a resilient lip · CPC title

• F16J15/43 Primary

  kept in sealing position by magnetic force · CPC title

• F16J15/3452

  the pressing force resulting from the action of a spring · CPC title