JP2008202526A - Scroll compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll compressor in which seizure is prevented from occurring. <P>SOLUTION: In this scroll compressor, a fixed scroll 60 having a fixed side lap 62 and a rotary scroll 2 having a rotary side lap 2b are installed in a housing H1 with both laps engaged with each other. The fixed scroll 60 is secured to the housing H1 side. The back pressure of the rotary scroll 2 is supported by a thrust receiving surface 30 on the housing H1 side. A softening coating (a softening member) 33 softened by heat is installed between the rotary scroll 2 and the thrust receiving surface 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a scroll compressor that can be used in an air conditioner.

  The scroll compressor includes a fixed scroll fixed to the housing side composed of a rear case and a front case, and a turning scroll that turns with respect to the fixed scroll. Both scrolls are provided upright on an end plate and an inner surface thereof. The spiral wrap of the fixed scroll and the spiral wrap of the orbiting scroll are meshed with the spiral wrap of the fixed scroll and the spiral wrap of the orbiting scroll is meshed with the spiral wrap of the orbiting scroll. And a fluid sucked into the compression chamber from a suction chamber disposed outside the spiral scroll of the fixed scroll or the orbiting scroll is compressed by a change in volume of the compression chamber, Outside the end plate of the fixed scroll through a discharge port provided at the center of the end plate of the fixed scroll. It ejected the eclipse discharge valve is opened.

The orbiting scroll is supported by a thrust plate (thrust sliding bearing) fixed to the housing side, and the orbiting scroll slides on the thrust plate. Therefore, when the dry operation is performed when the compressor is restarted after a long-term stop, abnormal wear or seizure of the sliding surface of the thrust plate becomes a problem. As a countermeasure against this problem, by applying a coating film of a solid lubricant to the sliding surface of the thrust plate, abnormal wear and seizure of the sliding surface can be prevented (see, for example, Patent Document 1).
Japanese Patent No. 3364016

  In the compressor, heat may be generated due to compression and sliding heat of the refrigerant, and the member may thermally expand. During normal operation, the refrigerant is cooled by flowing. However, if the refrigerant flow rate becomes less than the specified amount due to some abnormality, the refrigerant compression ratio is increased and the cooling effect by the refrigerant is lost, so that the scroll temperature is increased. For this reason, the orbiting scroll and the fixed scroll extend in the axial direction due to thermal expansion, and the tooth tip (lap tip) of the orbiting scroll and the fixed scroll comes into contact with the tooth bottom (fixed side end plate, or orbiting side end plate). The fixed scroll is stretched. If the operation is continued in this state, the scroll temperature further increases due to frictional heat, and thermal expansion is promoted. As a result, seizure may occur at the scroll tooth tip / bottom and the thrust bearing. In a scroll compressor, in order to improve the compression performance, it is necessary to make the tip gap as small as possible and reduce gas leakage. However, if the tip gap is made small, the tip surface of the spiral wrap is the wrap tooth of the counterpart scroll member. There is a risk of touching the bottom and causing seizure. For this reason, the chip gap is set in the conflicting demands between improving performance and ensuring reliability.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a scroll compressor capable of preventing the occurrence of seizure.

  According to a first aspect of the present invention, a fixed scroll having a fixed side wrap and a rotary scroll having a turning side wrap are provided in a housing in a state where both the wraps are engaged with each other, and the fixed scroll is provided. In a scroll type compressor that is fixed to the housing side and supports the back pressure of the orbiting scroll by a thrust pressure receiving surface on the housing side, the softening is caused by heat between the orbiting scroll and the thrust pressure receiving surface. A softening member is provided.

  When the scroll temperature rises excessively, the surface pressure supported by the thrust pressure receiving surface increases due to thermal expansion acting between the orbiting scroll and the fixed scroll. In this case, when the softening member is softened, the increase in the surface pressure can be mitigated, and seizure at the scroll tooth tip / bottom, thrust bearing, and the like can be prevented.

  A thrust plate that is a sliding bearing is provided between the orbiting scroll and the thrust pressure receiving surface, and the softening member is located between the thrust plate and the thrust pressure receiving surface, and the thrust plate The same action and effect can be obtained also by fixing to either one of the thrust pressure receiving surfaces. The softening member can be selected from those that soften at a temperature of 130 ° C. or higher and 150 ° C. or lower, which is a temperature at which seizure occurs. For example, the softening member can be a resin such as polyethylene or polyester resin. After cooling and returning to normal operation, the softening member hardens with the clearance slightly widened, and normal operation can be obtained. The clearance displacement at this time is slight.

  According to the scroll compressor of the present invention, when the temperature of the scroll rises, the softening member that supports the back pressure of the scroll softens and acts between the orbiting scroll and the fixed scroll due to thermal expansion, and the thrust pressure receiving surface The surface pressure supported by is absorbed. Therefore, burn-in between the turning scroll and the fixed scroll can be prevented.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a scroll compressor 1 according to this embodiment. The housing H1 is formed by combining the front case 40 and the rear case 50. The rear case 50 is a substantially hollow cylindrical member, and is fixed so that the front case 40 covers one opening. The front case 40 is formed with an opening through which the rotary shaft 6 passes, and a scroll described later is enclosed therein, and the front case 40 and the rear case 50 are fixed with the rotary shaft 6 protruding from the front case 40. .

  The scroll compression mechanism C housed in the housing H1 formed by combining the front case 40 and the rear case 50 described above includes the fixed scroll 60, the orbiting scroll 2, the Oldham link 3 that is a rotation preventing mechanism for the orbiting scroll 2, and the rotating shaft 6. And a main bearing 7 that pivotally supports the shaft. The fixed scroll 60 has a spiral wrap 62 standing on a substantially circular fixed side end plate 61.

The fixed scroll 60 is provided with a through hole serving as a discharge port 9 in the center of the fixed side end plate 61. The discharge port 9 is a portion that discharges the high-pressure fluid compressed by the scroll compression mechanism C. The discharge port 9 is attached with a discharge valve 10 that is opened and closed by the action of the pressure of the high-pressure fluid. Yes.
The discharge valve 10 is made of an elastic member, and the movable range in the opening direction is restricted by the retainer 11. The discharge valve 10 closes the discharge port 9 in close contact with the valve seat 12 in a natural state where no pressure is received. However, in a state where pressure is received from the inside of the discharge port 9, the discharge port 9 can be opened because the free end side that is in close contact with the valve seat 12 is separated by elastic deformation. Therefore, when the pressure in the discharge port 9 decreases, the discharge port 9 can be automatically closed by the elasticity of the discharge valve 10 itself.

The orbiting scroll 2 includes an orbiting side end plate 2a and a spiral wrap 2b standing on the inner surface thereof, and an eccentric bush 15 orbits in a boss 14 standing on the outer surface of the orbiting side end plate 2a. The bearings 16 are rotatably fitted through the bearings 16. An eccentric pin 17 protruding from the fixed scroll side end of the rotating shaft 6 is rotatably fitted in the hole formed in the eccentric bush 15.
The orbiting scroll 2 is eccentric by a predetermined distance from the fixed scroll 60 described above, and is displaced by an angle of 180 degrees to engage the spiral wraps 2b and 62, thereby forming a plurality of sealed spaces P therein. It can be formed.

  Reference numeral 19 denotes a flat plate-shaped thrust plate, which supports the orbiting scroll 2 by the sliding contact of the back surface of the orbiting scroll 2. The thrust plate 19 is made of a thin steel plate such as an SK material, and is supported by a thrust pressure receiving surface 30 formed on the inner side surface of the front case 40. The thrust plate 19 is prevented from rotating with respect to the thrust pressure receiving surface 30 so that it does not turn along with the orbiting scroll 2 even during the revolution orbiting motion of the orbiting scroll 2.

  The orbiting scroll 2 receives the driving force from the driving source (not shown) to the rotating shaft 6, so that the Oldham link is connected to the orbiting scroll 2 via the revolution turning mechanism including the rotating shaft 6, the eccentric pin 17, the eccentric bush 15, and the boss 14. Rotating and turning on a circular orbit with a turning radius while being prevented from rotating by 3.

Therefore, a fluid such as refrigerant gas compressed by the scroll compressor enters the sealed housing H1 from a suction port (not shown), and is sucked into the sealed space P through a fluid passage (not shown). While this fluid is compressed as the volume of the sealed space P decreases due to the revolving orbiting motion of the orbiting scroll 2 and the position of the sealed space P moves to the discharge port 9 side in the center, At the center of the scroll compression mechanism C, the discharge valve 10 is pushed open from the discharge port 9 provided on the fixed side end plate 61 of the fixed scroll 60 and guided to a pipe (not shown) and discharged to the outside of the scroll compressor. Is done.
A thrust load acts on the orbiting scroll 2 by the compressed gas in the sealed space P. This thrust load is supported by the thrust pressure receiving surface 30 via the thrust plate 19.

The structure of the thrust plate 19 is shown in detail in FIG.
The thrust plate 19 includes a thin steel plate 31 such as an SK material. A coating film 32 is formed on the side surface of the orbiting scroll 2 of the steel plate 31 by applying and firing a solid lubricant based on PTFE [tetrafluoroethylene resin]. A softening coating (softening member) 33 is formed on the other side surface of the steel plate 31 (the thrust pressure receiving surface 30 side). A thrust plate 19 is constituted by the steel plate 31, the coating film 32, and the softening coating 33.

  The softening coating 33 is a material such as a resin that softens at a temperature of about 130 ° C. or higher and 150 ° C. or lower. In the present embodiment, polyethylene or polyester resin is used. The softening coating 33 is a coating applied to the surface of the steel plate 31 or a sheet-like material fixed to the steel plate 31. The thickness of the softening coating 33 is several tens of μm.

In the scroll compressor configured as described above, when the scroll temperature rises, the tooth tips (wraps 2b and 62) of the orbiting scroll 2 and the fixed scroll 60 are caused to thermally expand due to thermal expansion (fixed side end plate 61, orbiting side). In contact with the end plate 2a), the swivel and fixed scrolls are stretched.
In this embodiment, when such a temperature condition is met, the softening coating 33 melts and acts between the orbiting scroll 2 and the fixed scroll 60 due to thermal expansion to reduce the surface pressure supported by the thrust plate 19. Absorb. Thereafter, after returning to normal operation, the softening coating 33 is cured with the clearance slightly widened, and a normal action can be obtained. The clearance displacement at this time is slight.

  Thus, according to the scroll compressor of this embodiment, when the temperature of the scroll rises, the softening coating 33 melts, so that the orbiting scroll 2 and the fixed scroll 60 can be prevented from seizing.

  Although the softening coating 33 is provided on the thrust plate 19 in the above embodiment, the softening coating 33 is provided on the thrust pressure receiving surface 30 side (for example, application or sheet-like material is fixed). Of course it is good.

It is sectional drawing which showed the scroll type compressor which concerns on this invention. It is the expanded sectional view which showed the thrust plate periphery in the scroll type compressor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Scroll type compressor, 2 ... Revolving scroll, 2a ... Revolving side end plate, 2b ... Wrap, 3 ... Oldham link, 6 ... Rotating shaft, 7 ... Main bearing, 9 ... Discharge port, 10 ... Discharge valve, 11 ... Retainer, 12 ... Valve seat, 14 ... Boss, 15 ... Eccentric bush, 16 ... Slewing bearing, 17 ... Eccentric pin, 19 ... Thrust plate, 30 ... Thrust receiving surface, 31 ... Steel plate, 32 ... Coating film, 33 ... Softening coating (Softening member), 40 ... front case, 50 ... rear case, 60 ... fixed scroll, 61 ... fixed side end plate, 62 ... wrap, H1 ... housing, C ... scroll compression mechanism, P ... sealed space

Claims (4)

A fixed scroll having a fixed-side wrap and a turning scroll having a turning-side wrap are provided in a housing in a state where both the wraps are engaged with each other, the fixed scroll is fixed to the housing side, and the turning scroll is fixed. In the scroll type compressor that supports the back pressure of the housing at the thrust receiving surface on the housing side,
A scroll compressor comprising a softening member that is softened by heat between the orbiting scroll and the thrust pressure receiving surface.   A thrust plate that is a sliding bearing is provided between the orbiting scroll and the thrust pressure receiving surface, and the softening member is located between the thrust plate and the thrust pressure receiving surface, and the thrust plate The scroll compressor according to claim 1, which is fixed to any one of the thrust pressure receiving surface and the thrust pressure receiving surface.   The scroll compressor according to claim 1 or 2, wherein the softening member softens at a temperature of 130 ° C or higher and 150 ° C or lower.   The scroll compressor according to claim 3, wherein the softening member is a resin.

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