JP2512150B2 - Refrigeration air conditioning scroll compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a scroll compressor used in a refrigerator such as an air conditioner or a refrigerator.

2. Description of the Related Art FIG. 3 shows a vertical sectional view of a conventional scroll compressor.

A scroll compressor is a wrap (6) formed by an end plate (4) (5) and an involute upright on the end plate (4) (5) or a curve close to the involute.
An orbiting scroll (3) having (7) and a fixed scroll (2) are engaged with each other with the wraps (6) and (7) facing inward, and a discharge port (16) is arranged in the center of the fixed scroll (2). However, the orbiting scroll (3) is prevented from rotating by interposing an Oldham ring (15) with the frame (11) having the suction port (22) or with the fixed scroll (2). The shaft (8) of the orbiting scroll (3) is engaged with the eccentric part (10a) of the rotating shaft (10), and the orbiting sucrose (3) is orbited by the rotating shaft (10), so that the fixed scroll ( 2)
The fluid in the enclosed space formed by the orbiting scroll (3) is compressed.

This type of scroll compressor is disclosed in, for example, U.S. Pat. No. 3,884,599 and Japanese Patent Laid-Open No. 62-70682.

The rotary shaft (10) in a scroll compressor is normally arranged vertically, and its sliding parts (10b) (10c) are generally supported by two sets of upper and lower metal-based plain bearings (12a) (13a) and also eccentric. The part (10a) is engaged with the orbiting scroll (3) through a metal-based sliding bearing (9).

On the other hand, in the scroll compressor, the fluid pressure in the closed space formed by the fixed scroll (2) and the orbiting scroll (3) passes through the shaft (8) of the orbiting scroll (3) and the eccentric part of the rotating shaft (10). (10a),
It acts in a radial direction perpendicular to the eccentric direction.

However, the rotary shaft (10) is in a state in which it can be moved by a small amount in the radial direction within the range of the clearance existing between the rotary shaft (10) and the slide bearings (12a) (13a) facing each other. When the radial force due to the fluid pressure acts in such a state, the rotating shaft (10) moves to the upper slide bearing (1) that supports the sliding portion (10c).
2a) and lower slide bearing (13b) supporting the sliding part (10b)
It tilts in a) and rotates while being strongly pressed against each bearing (12a) (13a) while being strongly pressed.

As a result, the bearings (12a) (13a) cannot obtain sufficient oil film reaction force that can handle the load due to this fluid pressure, and the bearings (12a) (13a) make metal contact and wear increases. Occasionally, burn-in may occur.

Further, since the rotary shaft (10) is arranged vertically and has the oil sump (23) in the lower part of the chamber (1), it is possible to supply the lubricating oil to the upper bearing parts (9) (12) (13). Since it takes a long time, the oil may not be supplied in time at the time of start-up, and the bearings (12a) (13a) may run out of oil, causing wear or seizure.

As a means for improving the wear resistance and seizure resistance of the bearing portion of the scroll compressor, both of the bearing portions that support the orbiting scroll are conventionally known.
JP-A-62-70682 as means for solving oil shortage at startup
The publication discloses that an oil retaining portion is provided in order to speed up oil supply to the metal bearing. In addition, JP-A-63-
Japanese Patent No. 268993 discloses a method of forming a bearing with a ceramic material impregnated with oil.However, when a bush type bearing is formed of ceramic, it cannot be formed into a thin shape due to its brittleness. It has drawbacks such as difficulty and cost. Further, in the publication, as a conventional example, copper,
A method of applying or impregnating a self-lubricating agent such as ethylene tetrafluoride or molybdenum disulfide on the surface of a metal bearing based on aluminum, tin, or lead is shown, but oil is run out because the base is a metal. When the above occurs, the metals come into contact with each other, and wear resistance and seizure resistance cannot be said to be sufficient. Further, since the self-lubricating agent is applied to the surface or impregnated from the surface, the self-lubricating agent is easily slipped off and has a drawback that it is difficult to exert a sufficient effect for a long period of time. In addition, in Japanese Utility Model Laid-Open No. 59-114477, a self-lubricating material such as Teflon (tetrafluoroethylene) resin is used as a material for an eccentric bushing mechanism for driving an orbiting scroll to avoid metal contact and burn. Means to prevent sticking are shown. However, Teflon (ethylene tetrafluoride) has a problem that it tends to undergo thermal deformation creep at high temperatures. The ambient temperature of the compressor bearing is around 100 ° C, but the push itself generates heat due to sliding, so the temperature is considerably higher than the ambient temperature, and creep deformation occurs when a load is applied at this temperature. Means for impregnating the sintered alloy with Teflon in order to increase the deformation strength is also shown, but metal contact is unavoidable in this method as described above.

Means for Solving the Problems The present invention has been made based on the above matters,
Bimetal (1
9) A slide bearing in which a graphite or polyamideimide resin (21) mixed with graphite (20) is impregnated and fired is used.

Further, the surface of the bearing bush is finished by cutting and used.

Action The action of the present invention is to prevent seizure and wear, which is good for the self-lubricating action of graphite under extremely strict lubrication conditions.

The rotating shaft tilts due to the action of fluid pressure during compression of the scroll compressor, and the bearing is in one-side contact with the bearing, and even when the oil film cannot be formed, the bearing is made of resin,
The surface of the rotating shaft and the surface of the bearing bush are not in contact with each other, so that seizure hardly occurs. In addition, since guaphytes are uniformly distributed in the resin, the solid lubrication action can prevent wear and seizure.

Further, since the heat resistance of the resin is as high as 250 ° C. or higher, when the sliding condition such as a non-lubricated state at the time of starting is severe, there is no deformation or deterioration even if the push becomes a high temperature due to sliding heat, A highly reliable bearing can be provided.

Further, by finishing the bush surface by cutting, the precision of the bearing can be improved, and a sliding surface on which graphite is evenly distributed can be provided, and wear resistance and seizure resistance can be further improved.

Example Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a scroll compressor provided with an embodiment of the present invention, in which (1) is a chamber, (2) is a fixed scroll, and (3) is an orbiting scroll.

The fixed scroll (2) and the orbiting scroll (3) are intermeshed with disk-shaped end plates (4) and (5) and spiral wraps (6) and (7) formed upright on the end plates facing inward. Has been done.

The orbiting scroll (3) has a shaft (8) formed below the end plate (5).

The shaft (8) engages with the eccentric part (10a) of the rotary shaft (10) via a slide bearing (9).

The sliding parts (10b) (10c) of the rotating shaft (10) are supported by an upper slide bearing (12b) and a lower slide bearing (13b) mounted on the frame (11).

The rotating shaft (10) is rotated by an electric motor (14).

Due to the rotation of the rotating shaft (10), the orbiting scroll (3) is prevented from rotating by the Oldham ring (15) and makes an orbiting motion.

Gas is sucked and compressed into the fixed scroll (2) and the orbiting scroll (3) by the orbiting motion, discharged from the discharge port (16) into the chamber (17), and discharged from the discharge pipe (18). It

The lubricating oil in the oil sump (23) in the lower part of the chamber (1) passes through the hole of the rotary shaft (10) and the upper plain bearing (9).
It is supplied to (12b) and (13b).

If there is no lubricating oil in the slide bearings (9) (12b) (13b) or the holes of the rotating shaft (10) at the time of start-up, the time until the lubricating oil is supplied from the lower oil sump (23) is The bearing becomes unlubricated.

By the compression action of the fluid trapped by the fixed scroll (2) orbiting scroll (3), the sliding portion (3) passes through the orbiting scroll (3), the slide bearing (9), and the eccentric portion (10a) of the rotating shaft (10). The loads acting on 10b) and (10c) are received by the slide bearings (12b) and (13b).

The fluid pressure in the closed space depends on the eccentric part (10
In (a), since it acts in the radial direction perpendicular to the eccentric direction, the rotating shaft (10) tilts by the amount of the acting load and the clearance of the slide bearings (12b) (13b), and the upper slide bearing (12b). Upper and lower plain bearings (13b)
It becomes a single contact at the bottom of.

If the surface pressure locally applied to the bearing increases due to one-sided contact, it becomes difficult to form a sufficient oil film, and the sliding part (10
The oil film on the sliding surface of b) (10c) and the sliding bearings (12b) and (13b) will be broken and will be in solid contact.

As shown in FIG. 2, the plain bearings (12b) (13b) are
Bimetal (1
9) A structure in which a polyimide or polyamide-imide resin (21) mixed with graphite (20) is impregnated and fired on the top. The plain bearings (12b) (13
After b) is press-fitted into the frame (11), an appropriate amount of its surface is removed by cutting and finished to a predetermined dimensional accuracy.

Since the bases of the slide bearings (12b) and (13b) are made of resin, even if they make solid contact, the surface of the rotating shaft and the surface of the bearing bush do not come into metal-to-metal contact and seizure hardly occurs. . Further, since the graphite (20) is uniformly distributed in the resin (21), wear and seizure can be prevented by its solid lubricating action.

In addition, the precision of the bearing can be improved by finishing the push surface by cutting, and a sliding surface in which graphite is evenly distributed can be provided on the fired surface.
The wear resistance and seizure resistance can be further improved. The self-lubrication effect of graphite can prevent seizure.

In addition, the bearing of the present invention is a solid sintered bimetal (19).
Since it has a structure in which graphite (20) and resin (21) are impregnated and fired on the top, the plate thickness can be 1.5 to 3.0 mm, and there is no cracking or cracking during press fitting. Therefore, the bearing bush can be made thinner than when it is made of a ceramic or carbon stripping material.

The ambient temperature of the refrigeration air conditioning compressor bearing is around 100 ° C, and the actual bearing temperature is several tens of degrees higher than the ambient temperature.
The temperature is 60 ° C, and self-lubricating resin such as tetrafluoroethylene is used for bearings.

However, as described above, when a high surface pressure is applied in a non-lubricated state at the time of start-up, the temperature of the bearing portion becomes 200 ° C. or higher, and the resin strength such as ethylene tetrafluoride remarkably decreases due to thermal deformation.

The present invention is a resin having heat resistance of 250 ° C. or higher and self-lubricating property (for example, polyimide having a heat distortion temperature of 270 ° C. to 360 ° C., 26
Graphite is mixed into 0 to 273 ° C (polyamide imide) and impregnated and fired, so that not only does it not wear or seize even in a non-lubricated state at the time of startup, but also it does not cause thermal deformation.

That is, since the heat resistance of the resin (21) is as high as 250 ° C. or higher, when the sliding condition is unlubricated at the time of starting or the like and the sliding condition is severe, the bush deforms due to the sliding heat even if it is in a high temperature
It is possible to provide a highly reliable bearing that does not deteriorate.

Effects of the Invention As described in detail above, according to the present invention, seizure and wear of the bearing can be prevented even under severe lubrication conditions, and the life and reliability of the scroll compressor can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a scroll compressor provided with an embodiment of the present invention, FIG. 2 is an internal sectional view of a journal bearing in the compressor, and FIG. 3 is a vertical sectional view of a conventional scroll compressor. is there. 1 ... Chamber, 2 ... Fixed scroll, 3 ... Orbiting scroll, 4, 5 ... End plate, 6, 7 ... Wrap, 8 ...
Shaft, 12b, 13b …… Slide bearing, 14 …… Motor, 15 …… Oldham ring, 16 …… Discharge port, 19 …… Bimetal, 20…
… Graphite, 21… Resin.

Continuation of the front page (56) References JP-A-62-70682 (JP, A) JP-A-63-268993 (JP, A) Actually developed JP-A-59-114477 (JP, U)

Claims (2)

(57) [Claims] 1. A fixed scroll (2) and an orbiting scroll (3) for vertically forming a wrap (6) (7) having spirally wound inner and outer surfaces on an end plate (4) (5), said wrap (6). The fixed scroll (2) is fixed, and the shaft (8) of the orbiting scroll (3) is engaged with the eccentric part (10) of the rotating shaft (10).
a) and is rotated by the Oldham ring (15) to prevent its rotation, and the rotary shaft (10) rotates the bushes (12b) (13b) engaged with the frame (11). In the scroll compressor supported through, the bushes (12b) (13b) are impregnated and fired with a polyimide resin or a polyamide-imide resin mixed with graphite (20) on a bimetal (19) that is jointly sintered. A scroll compressor for refrigeration and air conditioning, which uses sliding bearings. 2. A scroll compressor for refrigerating and air conditioning according to claim 1, wherein the surfaces of the bushes (12b) (13b) are cut.