JPH0272224A - Sealing device for air rotary joint - Google Patents

Abstract

PURPOSE:To prevent any oil leakage in an oil seal from occurring and lubricate a seal ring as well as to make improvements in sealability by installing the seal reing, lowering the extent of pressure in lubricating oil flowing into an oil chamber and being pressed to the side of a sleeve under pressure, and making it so as to feed the seal ring with the lubricating oil. CONSTITUTION:Compressed being fed out of an air hose 70 flows into a space 54 from an air inflow port 69, flowing into an air chamber from this space 54 by way of an inlet port 40 and a passage 42, while the compressed air in the space 54 is sealed on a seal surface 79 of a seal ring 64. In addition, lubricating oil flows into this seal surface 79 from a clearance 78, lubricating this ring 64, and simultaneously the extent of sealability on the seal surface 79 is improved. On the other hand, lubricating oil fed out of a lubricating oil hose 75 flows into an oil chamber 72 from a lubricating oil inlet 74, and it flow into another oil chamber 73 by way of lubricating oil passages 80, 82, 81, then it returns from a lubricating oil outlet 76 and flows out to a hose 77. Since oil pressure in this lubricating system is low as a range of 0.1-0.2kg/cm<2>, any oil leakage from an oil seal 71 will not happen at all.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sealing device for an air rotary joint that supplies compressed air to pneumatic equipment such as an air clutch.

(Prior art and its problems) A conventional air rotary joint is constructed as shown in FIG. 2.

In FIG. 2 showing an automobile air clutch which is a type of pneumatic equipment, 10 is a flywheel on the engine side. A clutch cover 12 is fixed to the flywheel 10, and the pressure force generated by the annular pneumatic actuator to 14 (pneumatic equipment) of the clutch cover 12 is transmitted to the pressure plate 161 and the pressure plate 16. A clutch valve 18 is sandwiched between the flywheel 10.

The clutch disc 18 is spline-fitted to a human power shaft 20 of a transmission (not shown) disposed downstream of the air clutch. A cylindrical shaft 24 is fitted onto the outer periphery of the human power shaft 20 via a bush 22. The clutch cover 12 is fitted to the right end of the cylindrical shaft 24 in the drawing.

The left end of the cylinder shaft 24 is surrounded by a cover 26, and a chamber 28 is formed inside the bar 26.

There are two air seals 30a between the cover 26 and the cylinder shaft 24.
~30C are interposed, and air leakage is prevented by air seals 30a~30c, which will be described in detail later.

On the other hand, a control valve 32 operated by a clutch pedal 31 is connected to the cover 26, and the control valve 32 allows compressed air flowing from a compressor 34 via a pressure regulating valve 36 to a chamber 38 between an air seal 30a and an air seal 30b. The tube passes through the artificial hole 40 of the cylinder shaft 24 and flows into the passage 42 .

Further, an outlet hole 44 is connected to the left end of the passage 42, and the outlet hole 44 is connected to an air chamber 48 of the pneumatic actuator 14 through a passage 46 formed within the thickness of the clutch cover 12. .

However, since the lips of the air seals 30a to 30C are pressed against the cylindrical shaft 24 by the pressure of lubricating oil, oil leaks are likely to occur, and if the leaked oil enters the air clutch, the clutch may slip and become stuck (1-7). .

(Objective of the Invention) An object of the present invention is to provide a sealing device for an air rotary joint that can prevent leakage of lubricating oil.

(Structure of the Invention) (1) Technical Means The present invention provides an air rotary joint that supplies compressed air from the outside to pneumatic equipment through a rotating shaft, in which annular rings are formed at intervals in the axial direction so as to sandwich the air inlet of the rotating shaft. sleeves are fixed to two locations on the outer peripheral surface of the rotating shaft, and both sleeves are formed with annular flange portions extending radially outward so as to surround the air inlet. A substantially annular main cover that surrounds the space between the sleeves is provided rotatably with respect to the sleeve and fixed with respect to an external fixed member, and is connected to the main sleeve so as to cover the other sleeve in the radial direction. A substantially annular sub-cover is provided to surround the outer periphery, an annular seal ring is provided to press against each side of the flange facing the space, and a spring member is provided for press-contacting the seal ring to the side of the flange. an oil seal forming an air inlet in the main cover and an annular oil chamber communicating with a sealing surface between the seal ring and the side surface of the flange portion between the covers and the sleeves; A lubricating oil outlet communicating with the oil chamber is formed in one of both covers, a lubricating oil outlet communicating with the oil chamber is formed in the other cover, and a lubricating oil passage connecting both oil chambers is formed within the wall thickness of both covers. This is a sealing device for an air rotary joint, characterized in that the lubricating oil is supplied to the sealing surface by flowing low-pressure lubricating oil to both oil chambers.

(2) The lubrication port flowing at low pressure in the working oil chamber flows into the sealing surface and lubricates the sealing surface.

Since the lubrication port only flows at low pressure, oil leaks are less likely to occur.

(Example) In FIG. 1 showing an air clutch for an automobile employing the present invention, parts indicated by the same reference numerals as in FIG. 2 indicate the same or equivalent parts.

In FIG. 2, the cylinder shaft 24 (rotating shaft) is connected to the inner cylinder 50 and the outer cylinder 51.
A passage 42 is formed between the inner cylinder 50 and the outer cylinder 51. Sleeves 52 having an abbreviated cross section are fixed to the outer circumferential surface of the outer cylinder 51 at two locations in the axial direction, sandwiching the inlet hole 40 of the passage 42, by, for example, press fitting. A flange portion 53 extending radially outward is integrally formed on the sleeve 52, and the sleeves 52 face each other so as to sandwich the artificial hole 40 and form a space 54. The flange portion 53 is in pressure contact with the annular projection 51a of the outer cylinder 51.

The main cover 5 is located radially outward of the sleeve 52 at two locations.
5. A sub-cover 56 is provided. The main cover 55 has a substantially annular shape that is continuous over the entire circumference so as to surround the space 54 and the outside of the sleeve 52 on the right side. Main cover 5
A connecting plate 57 made of spring steel is connected to the outer peripheral surface of the clutch housing 58 with bolts 57a, and the connecting plate 57 is connected to a clutch housing 58 (fixing member). An air inlet 69 is perforated at one location in the circumferential direction of the main cover 55, and an air hose 70 is connected to the six air inlets.

A substantially annular sub-cover 56 is connected to the left end surface of the main cover 55 via a packing 60. The sub cover 56 has a first
Four portions 61 are formed at a plurality of locations at positions different from the sectional positions shown in the figure, and the sub cover 56 and the main cover 55 are connected by bolts 62 in the recessed portions 61.

Note that the main cover 55 and the sub-cover 56 are not limited to the illustrated structure, and the main cover 55 may surround the space 54 and the sleeve 52 on the left side, and the sub-cover 56 may surround the sleeve 52 on the right side.

A continuous annular seal ring 64 is in pressure contact with each side surface 63 of the flange portion 53 over the entire circumference.

The seal ring 64 is made of a highly wear-resistant material such as ceramic or carbon. Note that the material of the seal ring 64 can also be made of other materials.

A pin 65 that connects to the main cover 55 and the sub cover 56 is fitted into the outer side surface of the seal ring 64.
An O-ring 66 is attached to the outer circumferential surface of. A steel annular spring holder 6 is provided on the inner side of the seal ring 64.
7 is fitted, and between both spring holders 67 is a coil spring 6 that presses the seal ring 64 against the side surface 63.
8 (spring member) is compressed.

A rubber annular oil seal 71 is provided on the inner circumferential surface of the main cover 55 and the sub-cover 56 and is in sliding contact with the outer circumferential surface of the sleeve 52.
are provided respectively, and the oil seals 71 form annular oil chambers 72 and 73. The oil chambers 72, 73 communicate with a sealing surface 79 of the seal ring 64 through a small gap 78. A lubricating oil-filled lower 4 is bored at one location in the circumferential direction of the main cover 55 , and a lubricating oil feeding hose 75 is connected to the lubricating oil-filled lower 4 communicating with the oil chamber 72 . Similarly, a lubricating oil outlet hole is bored at one location in the circumferential direction of the sub cover 56, and a lubricating oil return hose 77 is connected to the lubricating oil outlet hole communicating with the oil chamber 73.

The main cover 55 and the sub cover 56 have a lubricating oil passage 80.81 bored in a position different from the lubricating oil inlet lower 4 and the lubricating oil outlet lower alour so as to communicate with the oil chamber 72,73. ．．
81 is connected by a lubricating oil passage 82 passing through the packing 60. The outer peripheral end of the lubricating oil passage 80.81 is a ball 84.
It is blocked. Therefore, the oil chambers 72 and 73 communicate with the lubricating oil passages 80 to 82, and the oil chambers 72 and 73 are in communication with each other through the lubricating oil passages 80 to 82, and approximately 0.1 to 0.2 kg/c-
Low-pressure lubrication flows from the lubricant feed hose 75 to the lubricant return hose 77.

Note that the lubricating oil filling lower 4 may be provided on the sub cover 56 and the lubricating oil outlet lower 7 may be formed on the main cover 55.

Next, the effect will be explained. Compressed air supplied from the air hose 70 flows into the space 54 through the air inlet 69, and flows from the space 54 into the space 48 through the artificial hole 40, passages 42, 44, 46 in sequence. The compressed air in the space 54 is sealed by seven sealing surfaces of the seal ring 64. Lubricating oil flows into the seven seal surfaces from a gap 78 communicating with the oil chambers 72 and 73 to lubricate the seal ring 64 and improve the sealing performance of the seal surface 79.

On the other hand, the lubricating oil sent from the lubricating oil feed hose 75 flows into the oil chamber 72 through the lubricating oil lower 4, sequentially flows through the lubricating oil passages 80, 82, and 81, flows into the oil chamber 73, and the lubricating oil flows into the oil chamber 73. The lubricant oil flows out from the output lower part to the lubricant return hose 77. The oil pressure of this lubrication system is 0.1~ enough to flow the lubricating oil.
Since the pressure is low at 0.2 kg/c-, the oil seal 71
There will be no oil leakage.

(Effects of the Invention) As explained above, in the air rotary joint sealing device according to the present invention, since the lubricating oil flowing into the oil chambers 72 and 73 is at a low pressure, oil leakage from the oil seal 71 can be prevented. For example, leaked oil will not adversely affect the operation of pneumatic equipment such as an air clutch.

A seal ring 64 is provided that presses against the side surface 63 of the sleeve 52, and the oil chamber 72.73 and the seal surface 79 are communicated with each other through a gap 78, for example, so as to supply lubricating oil to the seal surface 79 of the seal ring 64. can be lubricated, and the sealing performance of the seven sealing surfaces can be improved.

4. Drawing III (ill explanation) Fig. 1 is a schematic vertical cross-sectional view of an air clutch adopting the present invention;
FIG. 2 is a structural diagram showing a conventional example.

DESCRIPTION OF SYMBOLS 10... Flywheel, 12... Clutch cover 14... Pneumatic actuator 16... Pressure plate, 20... Input shaft, 24... Cylinder shaft, 42... Passage, 52...・Sleeve, 55...Main cover 56...Sub-cover 64...Seal ring, 71...Oil seal, 72,

Claims (1)

[Claims] In an air rotary joint that supplies compressed air from the outside to pneumatic equipment through a rotating shaft, annular sleeves are fixed at two locations on the outer peripheral surface of the rotating shaft at intervals in the axial direction so as to sandwich the air inlet of the rotating shaft, An annular flange extending radially outward is formed on both sleeves so as to surround the air inlet, and a substantially annular main cover is provided on the sleeve so as to surround the radial outer periphery of one of the sleeves and the space between the two sleeves. A substantially annular sub-cover is provided, which is rotatable relative to the main sleeve and fixed relative to the external fixed member, and is connected to the main sleeve and surrounds the outer periphery of the other sleeve in the radial direction.
an annular seal ring is provided so as to be in pressure contact with each side of the flange portion facing the space, a spring member is provided to press the seal ring with the side surface of the flange portion, and an air inlet is formed in the main cover; An oil seal forming an annular oil chamber communicating with the seal surface between the seal ring and the side surface of the flange is provided between both covers and both sleeves, and a lubricating oil inlet communicating with the oil chamber is provided in one of both covers. A lubricating oil outlet communicating with the oil chamber is formed on the other cover, and a lubricating oil passage connecting both oil chambers is formed within the wall thickness of both covers, allowing low-pressure lubricating oil to flow into both oil chambers. A sealing device for an air rotary joint, characterized in that lubricating oil is supplied to the sealing surface.