JP2002206646A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device capable of restraining acceleration of abrasion against high pressure and lessening the problem of heat generation due to frictional heat or the like to improve durability of a rotating shaft seal as a sealing device coping with high pressure of a coolant. SOLUTION: A pressure reducing seal is disposed separately from the rotating shaft seal. The pressure reducing seal is provided with a lip part formed by extending the tip part of the lip on a fluid storing chamber side on the fluid storing chamber side from the rotating shaft seal having a seal element interposed between a housing and a rotating shaft to be brought into sliding contact with the rotating shaft, and a rubber-made seal member disposed on the fluid storing chamber side from the seal element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device for a compressor for a car air conditioner.
The present invention relates to a sealing device corresponding to a compressor in which a rotating shaft rotates at high speed.

[0002]

2. Description of the Related Art A rotary shaft seal is used to prevent a fluid in a fluid storage chamber of a compressor for a car air conditioner, that is, a mixture of a refrigerant and oil acting as a lubricant from leaking from a rotary shaft sliding surface. It is well known. In recent years, refrigerant HFC has become a factor in depletion of the ozone layer.
134a is being abolished, and the next generation refrigerant C
The development of a compressor using O ₂ is underway.

[0003] However, when CO ₂ (hereinafter referred to as “new refrigerant”) is used as a refrigerant, the fluid pressure of the compressor becomes HF.
10 times or more higher than when C134a is used. Therefore, development of a rotary shaft seal corresponding to this high pressure is desired.

Conventionally, a rotary shaft seal for sealing a high-pressure refrigerant as shown in FIG. 2 is known. The rotary shaft seal 1 is interposed between a housing 6 such as a compressor and a rotary shaft 7. Then, the fluid containing the refrigerant and oil in the fluid storage chamber 8 is sealed.

[0005] The structure of the rotary shaft seal 1 is made of a material in which a rubber seal member 2 is adhered to an outer case 4 and a resin (particularly, PTFE) having a cut groove 31 formed in a sliding contact surface in sliding contact with the rotating shaft 7. The sealing element 3 is integrally formed by caulking with the outer case 4.

In other words, the rotary shaft seal 1 performs sealing by the tip portion 21 of the rubber seal member 2 abutting against the surface of the rotary shaft 7. Fluid leakage occurs. The leaked fluid is a PTF disposed on the atmosphere side 9 with respect to the rubber seal member.
The structure is to be sealed by the seal element 3 made of E, thereby preventing fluid leakage as the whole rotary shaft seal. That is, the fluid passing through the rubber seal member 2 and intervening on the sliding surface 32 of the seal element 3 is supplied to the fluid storage chamber 8 by the spiral cut groove 31 provided on the sliding surface 32 of the seal element 3. , The rotating shaft seal 1 as a whole fulfills a sealing function.

Since the fluid leaking from the rubber seal member 2 contains oil having a lubricating action, the leaked fluid is interposed between the seal element 3 and the rotating shaft surface, so that the frictional resistance is reduced. Is reduced, and wear of the seal element 3 is reduced. Therefore, the rubber seal member 2
In a configuration in which the seal is completely sealed, the lubrication effect of the rubber seal member 2 and the seal element 3 is impaired, and the life of the rotary shaft seal 1 is shortened.

[0008]

However, when a new refrigerant is used, the pressure of the refrigerant in the fluid storage chamber 8 is further increased, so that the pressure presses the surface of the rubber seal member 2 (P in FIG. Pressure)). That is, since the rubber seal member 2 is pressed by the rotating shaft 7, the rubber seal member 2
Abrasion increases, and heat generated by frictional heat between the rotating shaft surface and the tip end of the rubber seal member 2 increases.
The tip of the rubber seal member 2 is hardened, which causes a crack. Furthermore, the sealing element 3 pressed against the rubber sealing member 2 by high pressure is pressed in the direction of the rotation axis more than necessary, so that the frictional heat is increased and wear is increased. The result was worsening.

As described above, this rotary shaft seal 1
Is used to intentionally leak a small amount of fluid from the rubber seal member 2 so that the oil of the leaked fluid is used as a lubricant for the rubber seal member 2 and the seal element 3. When the member 2 is pressed against the rotating shaft 7 more than expected due to high pressure, no fluid is supplied to the sealing element 3, and the wear of the rubber sealing member 2 and the sealing element 3 is accelerated, and the rotating shaft seal 1 is There was also a problem that it did not work as designed.

Accordingly, the present invention provides a sealing device which responds to a high pressure of a refrigerant, which suppresses the promotion of abrasion from a high pressure, reduces the problem of heat generation due to frictional heat and the like, and improves the durability of the rotary shaft seal. An apparatus is provided.

[0011]

That is, in order to solve the above-mentioned problems, the present invention is provided between a housing and a rotating shaft.
A rotary shaft seal including a seal element that slides on the rotary shaft and a rubber seal member disposed closer to the fluid storage chamber than the seal element; and a rotary shaft seal disposed closer to the fluid storage chamber than the rotary shaft seal. A pressure reducing seal having a lip tip extending to the fluid storage chamber side along the outer peripheral surface of the rotary shaft, wherein a partition is provided between the rotary shaft seal and the pressure reducing seal. .

Further, the partition portion is provided so as to protrude integrally with the housing.
Further, the material of the pressure reducing seal is a polyamide resin.

[0013]

According to the rotary shaft seal of the present invention, the pressure reducing seal is disposed on the fluid storage chamber side of the rotary shaft seal and the partition is provided therebetween, so that the pressure of the fluid storage chamber is received by the pressure reducing seal. The partition can stably support the pressure reducing seal. As a result, even if the pressure of the fluid storage chamber becomes high, the pressure acting on the rubber seal member is reduced by the decompression seal, so that the frictional heat due to the sliding resistance of the rubber seal member is suppressed, and the rubber seal member is used. The problem of cracking due to curing can be prevented. Further, since the pressure on the rubber seal member is reduced, the pressure on the seal element is also reduced, so that the wear of the seal element is suppressed and the durability of the entire rotary shaft seal is improved.

In addition, since a partition part protruding integrally with the housing is provided and the pressure reducing seal and the rotary shaft seal are separated from each other, the influence of the frictional heat generated by the pressure reducing seal on the rotary shaft seal is small. That is, when a pressure reducing seal for reducing pressure is provided integrally with the rotary shaft seal, a small space is formed between the pressure reducing seal and the rotary shaft seal. As a result, the frictional heat generated by the pressure-reducing seal and the frictional heat generated by the rubber elastic member lose their escape areas and are confined in the space, so that the rubber elastic member may be hardened and cracked at an early stage. Such a problem can be suppressed by providing the seal separately and adjusting the distance to the rubber elastic member.

The fluid in the compressor is a mixture of refrigerant (gas) and oil (liquid). In a normal decompression seal, a fluid that is a mixture of a liquid and a gas leaks slowly but in a small amount. By using a polyamide resin as the decompression seal material, oil slowly leaks, but refrigerant leakage ( Gas leak) was found to stop.

That is, since the leakage of the refrigerant is stopped by using a polyamide resin as the material of the pressure reducing seal, the space A between the pressure reducing seal and the rotary shaft seal is a space in which almost only oil exists. Therefore, since there is almost no refrigerant kept at a high pressure, the rotary shaft seal does not need to be affected by the high pressure, so that the conventional rotary shaft seal can be applied sufficiently. Further, since the oil leaks slowly from the reduced pressure seal formed of the polyamide resin, the lubricating effect of the rotary shaft seal is not impaired.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a sealing device according to the present invention including a rotary shaft seal 1 and a pressure reducing seal 10.

The rotary shaft seal 1 of FIG. 1 is interposed between a housing 6 of a case such as a compressor and a rotary shaft 7,
It is used to seal a fluid composed of high-pressure refrigerant and oil acting as a lubricant stored in the fluid storage chamber 8 side.

As a specific configuration, a metal outer case 4 is bonded (including welding, baking, etc.) to both the outer peripheral surface of the cylindrical portion 41 and the inner flange portion 42 of the outer case 4.
It comprises an integrated rubber seal member 2, a seal element 3 with a cut groove 31, and a metal fitting 5.

The rubber sealing member 2 has a cylindrical covering portion 23 having an uneven outer peripheral surface in a free state so that a sealing effect can be obtained by utilizing elastic force on the inner peripheral surface of the housing 6.
And an inner flange coating portion 22 having a U-shaped cross section that covers both surfaces of the inner flange portion 41 on the fluid storage chamber 8 side, and protruding from the inner peripheral side of the inner flange coating portion 22 to the fluid storage chamber 8 side. Rubber lip 25
And a small protruding portion 24 which is convex in the free state in contact with the seal element 3 on the atmosphere side 9 of the inner flange covering portion 22 so that a sealing effect by the elastic force is obtained.

The rubber lip portion 25 has a tip portion 21 which gradually decreases in diameter toward the fluid storage chamber 8 side and has a tip portion 21 slidably in contact with the outer peripheral surface of the rotary shaft 7. Has a substantially circular arc shape, and the circular arc portion is the rotating shaft 7 during assembly.
Is brought into contact with the outer peripheral surface.

The seal element 3 is in the shape of an annular flat plate in a natural state, and is held between an outer case 4 to which a rubber seal member 2 is adhered and a metal fitting 5. When the distal end of the seal element 3 is inserted into the rotary shaft 7 so as to bend toward the fluid storage chamber, the outer peripheral surface of the rotary shaft 7 is deformed into contact with a certain width to form a sliding surface 32. The sliding surface 32 is provided with a spiral cut groove 31.

Next, the decompression seal 10 shown in FIG. 1 is a U-shaped ring having a U-shaped cross section. The opening 30 is disposed so as to face the fluid storage chamber 8 side. It has a lip portion 20 in contact. The lip portion 20 extends from the decompression seal main body 40 toward the fluid storage chamber 8 in an enlarged manner, and the tip of the lip portion 20 is in contact with the outer peripheral surface of the rotating shaft 7 so as to be sealable.

The material constituting the pressure reducing seal 10 is as follows.
There is no particular limitation as long as the sealing can be performed while receiving the high pressure of the fluid storage chamber 8, but PTFE, polyamide resin and the like are mentioned as examples. Examples of polyamide resins include polyhexamethylene adipamide (nylon 6
6), polyhexamethylene azeramide (nylon 6
9), polyhexamethylene sebasamide (nylon 61
0) and polyhexamethylene dodecanoamide (nylon 612), poly-bis- (p-aminocyclohexyl) methane dodecanoamide, polytetramethylene adipamide (nylon 46) or polyamides resulting from ring cleavage of lactams; Polycaprolactam (nylon 6), and polylauryl lactam. Further, polyamides produced by polymerizing at least two kinds of amines or acids used in producing the above-mentioned polymer, for example, polymers produced from adipic acid, sebacic acid, and hexamethylenediamine can be used. . Blends of polyamides, such as blends of nylon 66 and nylon 6, include copolymers such as nylon 66/6. In addition, when a polyamide resin is used as a material, injection molding becomes possible, so that it can be formed at a lower cost as compared with the case of using PTFE which is formed by cutting, and when a fluid composed of a liquid and a gas is sealed, A major feature is that there is no gas leakage.

The arrangement of the rotary shaft seal 1 and the pressure reducing seal 10 is determined by a partition 61 integrated with the housing.
The decompression seal 10 needs to be disposed on the fluid storage chamber 8 side, but the distance between the two seals is not particularly limited. For example, the space A may be separated to the extent that the space A does not become unnecessarily high in temperature due to the frictional heat generated by the sliding resistance of the pressure reducing seal 10 and the rubber seal member 2.

Here, the partitioning portion 61 has a surface facing the fluid storage chamber 8 so that the pressure-reducing seal 10 that has received pressure can be moved to the atmosphere side 9.
Is regulated to move to. Further, by extending the partitioning portion 61 to the vicinity of the outer peripheral surface of the rotating shaft 7, the pressure-reducing seal 1
Even if 0 receives a high pressure, the posture can be stably maintained.

Next, the sealing function of the sealing device of the present invention will be described. When the fluid composed of the refrigerant and the oil is maintained at a high pressure in the fluid storage chamber 8, the opening 30 of the pressure reducing seal 10 that is stably held by the partitioning portion 61 receives pressure, and the opening 30 is moved from the natural state. Open. As the opening is opened, the force with which the lip portion 20 is pressed against the outer peripheral surface of the rotating shaft 7 increases, and the sealing force increases, so that the fluid in the fluid storage chamber 8 can be prevented from leaking.

Here, when the rotating shaft 7 rotates, frictional heat is generated due to friction between the pressure reducing seal 10 and the rotating shaft 7, and a slight oil leakage from the pressure reducing seal 10 occurs.
In the case of this embodiment, since the pressure-reducing seal 10 is made of a polyamide resin, the leakage is almost oil (liquid). Since this oil passes through the contact surface between the lip portion 20 of the pressure reducing seal 10 and the rotating shaft 7, it also has a lubricating effect.

The oil leaking from the pressure reducing seal 10 passes through the space A and is sealed by the rotary shaft seal 1. That is, since the fluid storage chamber 8 and the space A are shut off by the pressure reducing seal 10, the atmospheric pressure of the space A in FIG. Since the leakage of the refrigerant as a factor is suppressed, the pressure in the space A does not become high. Therefore, the rubber seal member 2 of the rotary shaft seal 1 can be sealed without being pressed more than necessary to the outer peripheral surface of the rotary shaft 7, and the oil leaking from the pressure reducing seal 10 acts as a lubricant of the rotary shaft seal 1. . Further, the tip portion 21 of the rubber sealing element 2
By intentionally leaking a very small amount of oil to the seal element 3 side, for example, in a round shape, the oil can be actively used as a lubricant for the seal element 3.

The oil leaking from the rubber seal member 2 is sealed by the seal element 3. That is,
The leaked oil acts as a lubricant by intervening on the sliding surface 32 of the seal element 3. Since a dynamic effect is caused and the interposed oil is pushed back to the fluid storage chamber 8 side, the oil does not leak to the atmosphere side 9.

The embodiment of the present invention has been described above.
The design can be freely changed without departing from the gist of the present invention.
For example, an example in which a U-ring having a U-shaped cross section is used as the pressure reducing seal 10 has been described. However, a seal having a lip extending along the outer peripheral surface of the rotating shaft 7 toward the fluid storage chamber 8 may be used. It is not particularly limited. For example, a seal member having only a lip shown in FIG. 3 is also applicable.

Further, the rotary shaft seal 1 has been described as having a rubber seal member 2 and a seal element 3 respectively, but it is needless to say that a rotary shaft seal having a plurality of each may be used.

[0033]

According to the sealing device of the present invention as described above, the decompression seal is provided on the fluid storage chamber side of the rotary shaft seal. The pressure experienced is reduced. Therefore, the durability of the seal of the compressor is improved by the sealing device of the present invention.

Further, since the rotary shaft seal and the pressure reducing seal are provided separately, the respective distances, that is, the volume of space between the rotary shaft seal and the pressure reducing seal can be easily adjusted. Therefore, even if the sealing member is in sliding contact with the rotating member to generate frictional heat, the problem of hardening of the rubber member and generation of cracks due to heat generation can be avoided.

By molding the pressure reducing seal with a polyamide resin, a small amount of oil leaks slowly and the gaseous refrigerant hardly leaks, so that the pressure load on the rotary shaft seal can be reduced and the lubricating effect is impaired. Absent. In addition, by using a polyamide resin as a material, injection molding becomes possible, so that cutting molding can be omitted, and the production cost of a reduced-pressure seal can be reduced.

[Brief description of the drawings]

FIG. 1 is a view showing a sealing device of the present invention.

FIG. 2 is a view showing a conventional rotary shaft seal.

FIG. 3 is a diagram showing another embodiment of the present invention.

[Description of Signs] 1 rotary shaft seal, 2 rubber seal member, 3 seal element, 4 outer case, 5 metal fittings, 6 housing, 7 rotary shaft, 8 fluid storage chamber, 9 atmosphere side, 10 pressure reducing seal, 20
Lip part, 21 tip part, 22 inner flange covering part, 23 cylindrical covering part, 24 small protrusion, 25 rubber lip part, 30 opening, 31
Notch groove, 32 sliding surface, 40 pressure reducing seal body, 41 outer cylinder, 42 inner flange, 61 partition

Claims (3)

[Claims] 1. A rotary shaft seal including a seal element interposed between a housing and a rotary shaft and slidably contacting the rotary shaft, and a rubber seal member disposed closer to the fluid storage chamber than the seal element. And a decompression seal provided on the fluid storage chamber side of the rotary shaft seal and having a lip tip extending toward the fluid storage chamber along the outer peripheral surface of the rotary shaft. A sealing device, wherein a partition portion is provided between the seal and the seal. 2. The sealing device according to claim 1, wherein the partition portion is provided so as to protrude integrally with the housing. 3. The sealing device according to claim 1, wherein the pressure reducing seal is made of a polyamide resin.