JP2002122242A - Shaft seal device and compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong service life of a shaft seal device and improve its reliability. SOLUTION: A lip seal 30 is stored in a seal storage chamber 23 between a peripheral face 131 of a rotary shaft 13 and a front housing 12. The lip seal 30 is provided with a rubber lip ring 35 and a lip ring 36 made of resin. Diamondlike carbon films 39, 40 are provided in a slide contact part 351 of the rubber lip ring 35 coming into slide-contact with the peripheral face 131 of the rotary shaft 13 and a slide contact part 361 of the lip ring 36 made of resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft seal device and a compressor for preventing a fluid from leaking along a peripheral surface of a rotary shaft by bringing a lip ring into contact with the peripheral surface.

[0002]

2. Description of the Related Art As disclosed in Japanese Patent Application Laid-Open No. Hei 7-139633, a rubber seal element (a lip ring in the present application) is provided to prevent leakage of fluid along the peripheral surface of a rotating shaft. A shaft sealing device is used. This type of shaft sealing device is applied to, for example, a rotating shaft of a compressor constituting a refrigeration circuit.

[0003]

The sealing element is
It is pressed against the peripheral surface of the rotating shaft by the pressure of the fluid. If the pressure of the fluid is high, the friction between the seal element and the peripheral surface of the rotating shaft increases, and the seal element is easily worn by sliding contact with the peripheral surface of the rotating shaft. Wear of the sealant reduces the sealability. A decrease in the sealing performance due to wear of the sealant shortens the life of the shaft sealing device. In particular, when carbon dioxide is used as a refrigerant in a compressor, the working pressure of carbon dioxide as the fluid is a very high pressure as compared with a chlorofluorocarbon-based refrigerant. for that reason,
A seal element in a compressor using carbon dioxide as a refrigerant is easily worn.

[0004] It is an object of the present invention to extend the life of a shaft sealing device and improve reliability.

[0005]

According to the present invention, there is provided a shaft sealing device in which a lip ring is brought into contact with a peripheral surface of a rotating shaft to prevent fluid leakage along the peripheral surface. In the invention according to claim 1, a diamond-like carbon film is provided on a sliding portion of the lip ring with respect to the peripheral surface of the rotating shaft.

According to a second aspect of the present invention, in the first aspect,
The shaft sealing device includes a rubber lip ring and a resin lip ring, and at least a sliding contact portion of the rubber lip ring and a sliding contact portion of the resin lip ring with respect to a peripheral surface of the rotating shaft. On the other hand, diamond like
A carbon film was provided.

According to a third aspect of the present invention, in the second aspect,
A diamond-like carbon film was provided on a sliding portion of the rubber lip ring with respect to the peripheral surface of the rotating shaft.
In a fourth aspect of the present invention, in any one of the second and third aspects, a diamond-like carbon film is provided on a sliding contact portion of the resin lip ring with respect to a peripheral surface of the rotating shaft.

According to the first to fourth aspects of the present invention, the diamond-like carbon film which is very hard and has a very small coefficient of friction suppresses abrasion of the lip ring having the diamond-like carbon film.

According to the fifth to eighth aspects of the present invention, the compression operation body that partitions the compression chamber is moved by the rotation of the rotating shaft,
The invention of claim 5 is directed to a compressor that sucks refrigerant from a suction pressure region into the compression chamber by the operation of the compression operation body and discharges refrigerant from the compression chamber to a discharge pressure region. The leakage of the refrigerant along the peripheral surface of the rotating shaft is prevented by the shaft sealing device according to any one of claims 4 and 5.

[0010] The diamond provided on the lip ring
Like carbon film suppresses the wear of the lip ring. In a sixth aspect of the present invention, in the fifth aspect, a diamond-like carbon film is provided in a sliding contact area of the peripheral surface of the rotary shaft with respect to the shaft sealing device.

The diamond-like carbon film on the shaft sealing device is in sliding contact with the diamond-like carbon film provided on the peripheral surface of the rotating shaft. The configuration in which the diamond-like carbon film is provided on both the rotating shaft side and the shaft sealing device side suppresses wear of both the lip ring and the rotating shaft.

According to a seventh aspect of the present invention, in any one of the fifth and sixth aspects, the compressor supplies the refrigerant from the discharge pressure area to the control pressure chamber, and supplies the refrigerant from the control pressure chamber to the suction pressure area. A variable capacity compressor that changes the discharge capacity based on the differential pressure between the control pressure of the control pressure chamber and the suction pressure of the suction pressure area, and the shaft sealing device is configured to remove the refrigerant from the control pressure chamber. The refrigerant is prevented from leaking along the peripheral surface of the rotating shaft.

[0013] Even when a control pressure having a large pressure fluctuation acts on the lip ring, the diamond-like carbon film provided in the shaft sealing device suppresses abrasion of the lip ring. The shaft sealing device of the present invention is suitable as a shaft sealing device for a variable displacement compressor.

According to an eighth aspect of the present invention, in any one of the fifth to seventh aspects, carbon dioxide is used as the refrigerant.
The shaft sealing device of the present invention is suitable as a shaft sealing device of a compressor using carbon dioxide having a high working pressure as a refrigerant.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is embodied in a variable displacement compressor will be described below with reference to FIGS. In the present embodiment, carbon dioxide is used as a refrigerant.

As shown in FIG. 1, a rotary shaft 13 is supported by a front housing 12 and a cylinder block 11 which form a control pressure chamber 121. The rotating shaft 13 obtains a rotational driving force from an external driving source (for example, a vehicle engine).
A rotation support 14 is fixed to the rotation shaft 13, and a swash plate 15 is supported so as to be slidable and tiltable in the axial direction of the rotation shaft 13. Guide pin 1 on swash plate 15
6 is fixed. The guide pin 16 is attached to the rotating support 1.
4 is slidably fitted in a guide hole 141 formed in the guide hole 141. The swash plate 15 has a guide hole 141 and a guide pin 1.
6 can be tilted in the axial direction of the rotating shaft 13 and can rotate integrally with the rotating shaft 13. The tilting of the swash plate 15 is guided by the slide guide relationship between the guide hole 141 and the guide pin 16 and the slide support action of the rotating shaft 13.

The inclination angle of the swash plate 15 can be changed based on a change in the control pressure in the control pressure chamber 121. When the control pressure in the control pressure chamber 121 increases, the tilt angle of the swash plate 15 decreases, and when the control pressure in the control pressure chamber 121 decreases, the tilt angle of the swash plate 15 increases. The refrigerant in the control pressure chamber 121 flows out to the suction chamber 191 in the rear housing 19 via a pressure release passage (not shown), and the refrigerant in the discharge chamber 192 in the rear housing 19 passes through a pressure supply passage (not shown). The pressure can be supplied to the control pressure chamber 121 via the control pressure chamber 121. A capacity control valve 2 is provided on the pressure supply passage.
5 from the discharge chamber 192 to the control pressure chamber 121.
The flow rate of the refrigerant supplied to is controlled by the capacity control valve 25. When the flow rate of the refrigerant supplied from the discharge chamber 192 to the control pressure chamber 121 increases, the control pressure in the control pressure chamber 121 increases, and when the flow rate of the refrigerant supplied from the discharge chamber 192 to the control pressure chamber 121 decreases, the control pressure chamber 121 decreases. The control pressure inside is reduced. That is, the inclination angle of the swash plate 15 is controlled by the capacity control valve 25.

The maximum inclination angle of the swash plate 15 is defined by the contact between the swash plate 15 and the rotary support 14. The minimum inclination angle of the swash plate 15 is defined by the contact between the circlip 24 on the rotating shaft 13 and the swash plate 15.

In the cylinder block 11, the rotating shaft 13
A plurality of cylinder bores 111 (only one is shown in FIG. 1) are arranged around the. The piston 17 is housed in each cylinder bore 111. The piston 17 serving as a compression operation body defines a compression chamber 112 in the cylinder bore 111. Rotational movement of the swash plate 15 that rotates integrally with the rotation shaft 13 is converted into reciprocating movement of the piston 17 via the shoe 18, and the piston 17 reciprocates in the cylinder bore 111.

The refrigerant in the suction chamber 191 in the suction pressure region is sucked from the suction port 201 on the valve plate 20 to the suction port on the valve forming plate 21 by the reciprocating operation of the piston 17 (moving from right to left in FIG. 1). The valve 211 is pushed back and flows into the compression chamber 112. The refrigerant flowing into the compression chamber 112 is moved from the discharge port 202 on the valve plate 20 to the discharge valve 221 on the valve forming plate 22 by the forward movement of the piston 17 (moving from left to right in FIG. 1).
And is discharged into the discharge chamber 192 which is the discharge pressure region.

The discharge chamber 192 and the suction chamber 191 are connected via an external refrigerant circuit 26. The refrigerant flowing from the discharge chamber 192 to the external refrigerant circuit 26 returns to the suction chamber 191 via the condenser 27, the expansion valve 28, and the evaporator 29.

A seal accommodating chamber 23 is formed between the peripheral surface 131 of the rotating shaft 13 and the front housing 12, and a lip seal 30 as a shaft sealing device is provided in the seal accommodating chamber 2.
3 housed.

The lip seal 30 includes a ring case 31
A rubber O-ring 32 fitted in the concave ridge 311 on the outer peripheral side of the ring case 31, and a pair of ring-shaped holding brackets 33 and 34 disposed on the inner periphery of the ring case 31.
And the rubber lip ring 3 held by the holding bracket 33
5, a resin-made lip ring 36 held by a holding metal member 34, and a ring-shaped reinforcing metal member 37 for reinforcing the rubber lip ring 35. The resin lip ring 36 is made of a fluorine resin, for example, polytetra
Made of fluoroethylene. The position of the ring case 31 is restricted between the end surface 231 of the seal housing chamber 23 and the circlip 38 attached to the peripheral surface 232 of the seal housing chamber 23. O-ring 32 is ring case 3
1 and the peripheral surface 23 of the seal accommodating chamber 23
And 2 are joined. The lip ring 36 made of resin is
The holding member 33 is located between the pair of holding members 33 and 34.
Is disposed between a rubber lip ring 35 and a resin lip ring 36.

As shown in FIG. 2, in a state where the lip seal 30 is assembled in the seal accommodating chamber 23 and the rotary shaft 13 is passed through the lip seal 30, the inner peripheral side of the rubber lip ring 35 and the resin lip ring 36 is the rotating shaft 1
3 is in contact with the peripheral surface 131. A diamond-like carbon film 39 is formed on a sliding contact portion 351 of the rubber lip ring 35 which is in sliding contact with the peripheral surface 131 of the rotating shaft 13 by a vapor deposition method. A diamond-like carbon film 40 is formed on the sliding contact portion 361 of the resin lip ring 36 that is in sliding contact with the peripheral surface 131 of the rotating shaft 13 by a vapor deposition method.

The sliding portion 361 of the resin lip ring 36
Is formed with a spiral groove 362 as shown in FIG. The resin lip ring 36 before the assembly of the lip seal 30 is a flat ring as shown in FIG. The spiral groove 362 is formed after the diamond-like carbon film 40 is provided on the resin lip ring 36 as shown in FIG. The spiral groove 362 is formed on the peripheral surface 131 of the rotating shaft 13 by the relative rotation with the rotating shaft 13.
And the lubricating oil between the sliding contact portion 361 is returned to the control pressure chamber 121 side.

In the first embodiment, the following effects can be obtained. (1-1) The rubber lip ring 35 and the resin lip ring 36 slidably contacting the peripheral surface 131 of the rotating shaft 13 prevent the refrigerant from leaking from the control pressure chamber 121 along the peripheral surface 131 of the rotating shaft 13. To prevent. The O-ring 32 prevents leakage of the refrigerant from the control pressure chamber 121 along the peripheral surface 232 of the seal accommodating chamber 23.

The pressure in the control pressure chamber 121 is controlled by a rubber lip ring 35 and a resin lip ring 36.
3 is pressed against the peripheral surface 131. The diamond-like carbon films 39 and 40 of the sliding portions 351 and 361 are in direct contact with the peripheral surface 131 of the rotating shaft 13. The diamond-like carbon films 39 and 40 are very hard and have a very small coefficient of friction. Since the diamond-like carbon films 39 and 40 having such properties come into contact with the peripheral surface 131 of the rotating shaft 13, wear of the rubber lip ring 35 and the resin lip ring 36 is suppressed. Suppression of wear of the lip rings 35 and 36 leads to a longer life of the lip seal 30.

(1-2) Since the friction coefficient of the diamond-like carbon films 39 and 40 is extremely small, the rotation shaft 1
3 and the lip seal 30 have small frictional resistance. Therefore, power loss due to frictional resistance is very small, and power for driving the compressor can be reduced.

(1-3) As the abrasion of the slidable area of the peripheral surface 131 of the rotating shaft 13 with respect to the lip rings 35 and 36 progresses, the sealing performance of the lip seal 30 decreases. In particular, in the case of using carbon dioxide as a refrigerant whose operating pressure is much higher than that of a chlorofluorocarbon-based refrigerant, the conventional configuration in which the lip ring without the diamond-like carbon films 39 and 40 directly contacts the peripheral surface 131 of the rotating shaft 13 Then, the progress of wear of the lip ring is rapid. Since the friction coefficient of the diamond-like carbon films 39 and 40 is extremely small, wear of the sliding contact area on the rotating shaft 13 side that slides on the diamond-like carbon films 39 and 40 is also suppressed.

(1-4) The rubber lip ring 35 is easily thermally degraded, and the sealing performance of the thermally degraded rubber lip ring 35 is reduced. Generally, the contact area of the resin lip ring 36 with the rotating shaft 13 is larger than that of the rubber lip ring 35. Therefore, the resin lip ring 3
The heat generated by the sliding contact between the rotary shaft 13 and the rotary shaft 13 is larger than the heat generated by the sliding contact between the rubber lip ring 35 and the rotary shaft 13. To suppress the heat generation of the resin lip ring 36,
This contributes to suppressing thermal deterioration of the adjacent rubber lip ring 35. The diamond-like carbon film 40 reduces heat generation in the sliding portion of the resin lip ring 36 and suppresses thermal degradation of the adjacent rubber lip ring 35.

(1-5) The control pressure in the control pressure chamber 121 may be equivalent to the discharge pressure, and the control pressure in the control pressure chamber 121 fluctuates greatly. When the control pressure having large pressure fluctuation acts on the rubber lip ring 35, and when there is no diamond-like carbon film 39, the rubber lip ring 3
No. 5 is liable to wear. The lip seal 30 including the diamond-like carbon film 39 is particularly suitable as a shaft sealing device for a variable displacement compressor.

Next, a second embodiment shown in FIG. 4 will be described. The same components as those in the first embodiment are denoted by the same reference numerals. The diamond-like carbon film 39A is
The diamond-like carbon film 40A has penetrated into the bonding region between the rubber lip ring 35 and the holding bracket 33, and has entered the bonding region between the resin lip ring 36 and the holding bracket 34. In.

Carbon dioxide is used at a higher pressure than fluorocarbon refrigerants. The carbon dioxide can penetrate into the inside of the rubber, which is the material of the rubber lip ring 35, and the inside of the fluorine resin, which is the material of the resin lip ring 36. In particular, rubber, which is a material of the rubber lip ring 35, easily transmits carbon dioxide.

Rubber lip ring 35 and holding bracket 33
The diamond-like carbon film 39A that has penetrated into the bonding region between
To prevent carbon dioxide from permeating through. In addition, the diamond-like carbon film 40A that has entered the bonding region between the resin lip ring 36 and the holding fitting 34
Prevents the permeation of carbon dioxide through the lip ring 36 made of resin.

Next, a third embodiment shown in FIG. 5 will be described. The same reference numerals are used for the same components as those in the first embodiment. In the third embodiment, before assembling the lip seal 30, a diamond-like carbon film 39B is formed by vapor deposition on the entire surface of the rubber lip ring 35, and the entire surface of the resin lip ring 36 is formed. A diamond-like carbon film 40B is formed by evaporation. In this embodiment, the permeation of carbon dioxide in the rubber lip ring 35 and the permeation of carbon dioxide in the resin lip ring 36 are more reliably performed than in the second embodiment.

Next, a fourth embodiment shown in FIG. 6 will be described. The same reference numerals are used for the same components as those in the first embodiment. In the fourth embodiment, after assembling the lip seal 30, the entire surface of the lip seal 30 is coated with diamond.
Like carbon film 41 is formed by vapor deposition. In this embodiment, the same effects as in the third embodiment can be obtained.

Next, a fifth embodiment shown in FIG. 7 will be described. The same components as those in the second embodiment are denoted by the same reference numerals. In the fifth embodiment, the diamond-like carbon is formed in the sliding contact area of the peripheral surface 131 of the rotating shaft 13 which contacts the sliding contact part 351 of the rubber lip ring 35 and the sliding contact part 361 of the resin lip ring 36. The film 42 is formed by vapor deposition. The diamond-like carbon films 39A and 40A on the lip seal 30 side are in sliding contact with the diamond-like carbon film.

The diamond-like carbon film 42 on the side of the rotating shaft 13 suppresses wear of the rotating shaft 13 in the sliding contact area with the lip rings 35 and 36. In addition, a diamond-like carbon film 39 having extremely small friction is used.
The configuration in which the A, 40A and the diamond-like carbon film 42 are in sliding contact with each other is more effective in suppressing heat generation and reducing frictional resistance than in the above embodiments.

In the present invention, the following embodiments are also possible. (1) The resin lip ring 36 is less likely to be worn than the rubber lip ring 35, and the rubber lip ring 35 is solely responsible for the sealing function. Therefore, the influence of the abnormal wear of the resin lip ring 36 is small compared to the abnormal wear of the rubber lip ring 35. Therefore,
Even if the lip seal 30 is provided with a diamond-like carbon film only on the rubber lip ring 35 side, the life is extended and the reliability is improved.

(2) A diamond-like carbon film is provided only on the resin lip ring 36 side. In addition to suppressing the abrasion of the resin lip ring 36, the effect of reducing the heat generation at the sliding portion of the resin lip ring 36 and suppressing the deterioration of the rubber of the adjacent rubber lip ring 35 is obtained. .

(3) When a diamond-like carbon film is provided on the rotating shaft 13 side, a rubber lip ring 3
The diamond-like carbon film is provided only in the sliding contact area of the peripheral surface 131 of the rotating shaft 13 in contact with the sliding contact portion 351 of No. 5.

(4) When a diamond-like carbon film is provided on the rotating shaft 13 side, a resin lip ring 3
The diamond-like carbon film is provided only in the sliding contact area of the peripheral surface 131 of the rotating shaft 13 in contact with the sliding contact portion 361 of No. 6.

(5) When a diamond-like carbon film is provided on the rotating shaft 13 side, the peripheral surface 131 of the rotating shaft 13
Provide a diamond-like carbon film throughout. That is, the peripheral surface 131 of the rotating shaft 13 that contacts the swash plate 15
, The rotating shaft 1 that slides on the swash plate 15 when the swash plate tilt angle is changed
3 is provided with a diamond-like carbon film in the region of the peripheral surface 131.

(6) The present invention is applied to a shaft sealing device including only a rubber lip ring. (7) The present invention is applied to a shaft sealing device including only a resin lip ring. (8) The present invention is applied to a shaft sealing device that prevents refrigerant from leaking along a rotating shaft from a suction pressure region in a compressor.

(9) The present invention is applied to a shaft sealing device for preventing fluid leakage along a rotating shaft other than a compressor.

[0046]

As described above in detail, according to the present invention, the diamond lip ring slides against the peripheral surface of the rotating shaft.
Since the like carbon film is provided, there is an excellent effect that the life of the shaft sealing device can be extended and the reliability can be improved.

[Brief description of the drawings]

FIG. 1 shows a first embodiment, and is a side sectional view of the entire compressor in which a main part enlarged sectional view is incorporated.

FIG. 2 is an enlarged sectional view of a main part.

FIG. 3A is a front view showing a state in which a diamond-like carbon film is formed by vapor deposition on a resin lip ring before assembling a lip seal. (B) is a front view showing the state where the spiral groove was formed.

FIG. 4 is an enlarged sectional view of a main part showing a second embodiment.

FIG. 5 is an enlarged sectional view of a main part showing a third embodiment.

FIG. 6 is an enlarged sectional view of a main part showing a fourth embodiment.

FIG. 7 is an enlarged sectional view of a main part showing a fifth embodiment.

[Explanation of symbols]

112: Compression chamber. 121 ... Control pressure chamber. 13 ... Rotary axis. 1
31 ... peripheral surface. 191, a suction chamber which is a suction pressure region. 192
... Discharge chamber which is a discharge pressure region. 30: Lip seal which is a shaft sealing device. 35 ... rubber lip ring. 36 ... Rip ring made of resin. 351, 361: sliding contact portion. 39,4
0, 39A, 40A, 39B, 40B, 41, 42 ... diamond-like carbon film.

Claims (8)

[Claims] 1. A shaft sealing device for preventing a fluid from leaking along a peripheral surface of a rotary shaft by bringing the lip ring into contact with a peripheral surface of the rotary shaft.・ Shaft sealing device with like carbon film. 2. The shaft sealing device includes a rubber lip ring and a resin lip ring, and a sliding portion of the rubber lip ring on a peripheral surface of the rotating shaft and a resin lip ring. The shaft sealing device according to claim 1, wherein a diamond-like carbon film is provided on at least one of the sliding contact portions. 3. The shaft sealing device according to claim 2, wherein a diamond-like carbon film is provided on a sliding portion of the rubber lip ring with respect to a peripheral surface of the rotating shaft. 4. The shaft sealing device according to claim 2, wherein a diamond-like carbon film is provided on a sliding portion of the resin lip ring with respect to a peripheral surface of the rotating shaft. . 5. A compression operation body that partitions a compression chamber is moved by rotation of a rotation shaft, and the operation of the compression operation body draws refrigerant from a suction pressure region into the compression chamber, and from the compression chamber to a discharge pressure region. A compressor for discharging a refrigerant, wherein the shaft sealing device according to any one of claims 1 to 4 prevents leakage of the refrigerant along a peripheral surface of the rotating shaft. 6. The compressor according to claim 5, wherein a diamond-like carbon film is provided in a sliding contact area of said rotating shaft with respect to said shaft sealing device. 7. A compressor supplies a refrigerant from a discharge pressure area to a control pressure chamber, extracts a refrigerant from the control pressure chamber to a suction pressure area, and controls the control pressure of the control pressure chamber and the suction of the suction pressure area. 6. A variable displacement compressor that changes a discharge capacity based on a pressure difference from a pressure, wherein the shaft sealing device prevents refrigerant leakage from the control pressure chamber along a peripheral surface of the rotating shaft. Item 7. The compressor according to any one of items 6. 8. The compressor according to claim 5, wherein carbon dioxide is used as a refrigerant.