JPH05332272A - Scroll compressor - Google Patents

Abstract

PURPOSE:To prevent occurrence of friction and wear even when fluorocarbon being short of lubricity is used by improving lubricating oil holding capacity of the end face part of the addendum of the laps of a scroll compressor. CONSTITUTION:A plurality of fine oil reservoir recessed parts 11 which are not opened to an operating chamber 3 and independent from each other and have a diameter (d) of 0.01-0.5mm, and a depth (h) of 0.5mm or less are formed in the end face parts of the addenda of the scroll laps 1a and 2a of a fixed scroll 1 or a revolving scroll by plastic processing or etching processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll body lubrication structure of a scroll compressor which is a kind of refrigeration / air conditioning compressor.

[0002]

2. Description of the Related Art In conventional scroll compressors used for refrigeration and air conditioning, dichlorodifluoromethane (hereinafter referred to as Freon 12) and chlorodifluoromethane (hereinafter referred to as Freon 22) are mainly used as working fluids. Freon 12 and 22 are used for lubrication of sliding parts.
A naphthenic or paraffinic mineral oil that is compatible with is used.

As is well known, the compression mechanism of a scroll compressor comprises a fixed scroll and an orbiting scroll having a spiral body of the same shape constituted by an involute curve or the like.
By rotating the orbiting scroll by ° and rotating the orbiting scroll around the fixed scroll without revolving with the orbiting radius e,
A plurality of crescent-shaped sealed volumes formed by the spiral body reduce the volume, and the working fluid is compressed. Lubrication of the sliding parts of fixed scrolls and orbiting scrolls is performed by introducing lubricating oil into the sliding parts.In particular, inside the compression mechanism where a crescent-shaped sealed volume is formed, the sliding parts are sealed. In general, the lubricating oil is mixed in the working fluid (refrigerant) to also lubricate the sliding portion of the spiral body, which also has a cooling effect. In scroll compressors, sealing and lubrication of the tooth tip surface of the spiral body is important for ensuring performance from the relationship of its motion form (swirl motion) and leakage area, but it is a well-known technique to improve the sealing property of the tooth tip surface. Are, for example, US Pat. No. 5,035,589.

By the way, in recent years, the destruction of the ozone layer due to CFCs and global warming have become problems, and the use of CFCs 12 having a high ozone depletion coefficient is gradually reduced and will be abolished in the future. It has become.

Under these circumstances, 1,1,1,2-tetrafluoroethane (hereinafter abbreviated as CFC134a) has been developed as a substitute for CFC12, and a compressor suitable for this refrigerant is practically used. Is desired.

[0006]

By the way, since the alternative refrigerant CFC 134a has almost no compatibility with mineral oil, which is a conventional lubricating oil, a polyalkylene glycol oil or a polyester oil in which CFC is soluble is used. If
There is a problem that the abrasion resistance of the sliding portion is reduced.

This is because when the conventional Freon 12 is used as a refrigerant, Cl atoms in the molecule serve as an extreme pressure agent.
While it reacts with Fe atoms of the metal base material forming the sliding portion to form an iron chloride film with good wear resistance on the surface, when CFC 134a is used, there are no Cl atoms, so iron chloride One of the causes is that such a film is not formed.

In the scroll compressor using the Freon 134a, the problem that the sliding portion of the compression mechanism is worn easily occurs.
In particular, the tooth tip surface of the spiral body is difficult to form an oil film due to the lubricating oil due to the swirling motion, and if oil runs out, not only the seal function (radial sealing) of the tooth tip surface section of the spiral body is impaired, but also significant friction occurs. It was revealed from the experiments conducted by the inventors of the present invention that there is a problem that the wear increases and the performance and reliability of the compressor deteriorate. In order to achieve an effective radial seal, this problem is applied to a scroll compressor of the type in which pressure is applied to the orbiting scroll or the fixed scroll to reduce the gap between the tooth tip surfaces of the scroll to obtain the radial seal. Remarkable. In contrast, the structure disclosed in U.S. Pat.No. 5,035,589 has a large number of linear grooves formed on the tooth tip surface portion of the spiral body to reduce internal leakage of the working fluid in the radial direction of the spiral body. However, since the groove opens in the working chamber, the effect of retaining oil was small, and the problems of friction and wear due to oil shortage were unavoidable.

An object of the present invention is to improve the reliability of the sliding portion of the compression mechanism of the scroll compressor when using the alternative refrigerant Freon 134a.

[0010]

SUMMARY OF THE INVENTION In a scroll compressor according to the present invention, a fixed scroll and an orbiting scroll, each having a spiral body of the same shape, are engaged with each other by rotating them by 180 ° without rotating the orbiting scroll with respect to the fixed scroll. In a scroll compressor that revolves around an orbiting radius e and lubricates a sliding portion with lubricating oil, at least one of the fixed scroll or the orbiting scroll has a tooth tip surface portion with a diameter of 0.01 to 0. It is characterized by the formation of many fine depressions with a depth of 0.5 mm and a depth of 0.5 mm or less.

[0011]

By forming a plurality of independent fine recesses in the tooth tip surface of the spiral body without opening to the working chamber, the lubricating oil mixed in the working fluid (refrigerant) is retained in the recesses by the capillary phenomenon. The lubricity is improved, the problems of friction and wear due to oil shortage are solved, and particularly, the reliability of the compression mechanism sliding portion of the scroll compressor using the alternative refrigerant CFC 134a can be improved.

[0012]

Embodiments of the present invention will be described in detail below with reference to embodiments shown in the drawings.

FIG. 1 is a cross-sectional view of a main part of a scroll compressor according to the present invention, which corresponds to a II-II cross section of FIG. 2 which is a cross-sectional view in the length direction of the scroll compressor. FIG. 3 is a plan view of the orbiting scroll viewed from the orbiting scroll side. FIG. 4 is an enlarged cross-sectional view of the tooth tip surface portion of the scroll of the fixed scroll or the orbiting scroll, which corresponds to the I-I cross section of FIGS. 1 and 3.

In the figure, reference numeral 1 denotes a fixed scroll, which comprises a fixed scroll 1a and an end plate 1b. Reference numeral 2 denotes a revolving scroll, which is composed of a revolving scroll 2a and an end plate 2b. The fixed spiral body 1a and the swirl spiral body 2a are configured by a smooth spiral structure having substantially the same shape and height. Reference numeral 3 is a working chamber formed between the scrolls 1 and 2, and 4 and 5 are suction ports and discharge ports of the working fluid formed in the fixed scroll 1. A crankshaft 6 drives the orbiting scroll 2 and is rotatably supported on the frame 8 by bearings 7. A bearing 9 for supporting the driven shaft 2c of the orbiting scroll 2 is provided at the end of the crankshaft 6. An Oldham ring 10 prevents the orbiting scroll 2 from rotating.
As a result, the crankshaft 6 is rotated by a motor (not shown), and the driven shaft 2c of the orbiting scroll 2 is eccentrically moved around the axis of the crankshaft 6 by the rotation of the crankshaft 6. Oldham Ring 10
Is converted into a turning motion by the action of. Reference numeral 11 denotes an oil sump concave portion formed on the tooth tip surface portions of the scrolls 1a and 2a of the fixed scroll 1 and the orbiting scroll 2, respectively, having a diameter d of 0.01 to 0.5 mm and a depth h of 0.5 mm or less. It consists of a plurality of independent spheres.

The compression operation of the scroll compressor according to the present invention configured as above will be described. Motor (not shown)
The crankshaft 6 is rotated by energizing the rotating shaft 2, and the orbiting scroll 2 makes an orbiting motion around the fixed scroll 1 without revolving around the orbiting radius e without rotating, and the working fluid sucked from the suction port 4 (CFC 134a). Is both scrolls 1,
The fluid enters the working chamber 3, which is a crescent-shaped sealed volume formed by the two spiral bodies 1a and 2a, and the volume is reduced as the crankshaft 6 rotates, so that the fluid is compressed. Then, the compressed fluid is finally discharged from the discharge port 5.

Lubrication inside the compression mechanism in which a crescent-shaped sealed volume, which is a sliding portion of the fixed scroll 1 and the orbiting scroll 2, is formed is carried out by using polyalkylene glycol oil compatible with the flon 134a in the flon 134a as a working fluid. , Performed by mixing a lubricating oil such as polyester oil. As a result, the oil introduced into the working chamber 3 is transferred to the scroll body 1 of each of the fixed scroll 1 and the orbiting scroll 2.
Fine oil sump recesses 1 formed on the tooth tip surfaces of a and 2a
It is held in the inside of 1 by a capillary phenomenon, and is used for lubrication and sealing of the sliding portion of the spiral body. Therefore, the scroll body 1 of each of the fixed scroll 1 and the orbiting scroll 2 is
The problem of running out of oil on the tooth tip surfaces of a and 2a is solved, and the reliability of the scroll compressor can be ensured even with the alternative refrigerant CFC 134a, which has severe lubrication conditions. Further, even in the scroll compressor using the present Freon 22, it is possible to improve the sealing performance of the tooth tip surface portion of the spiral body which has an important effect on the performance, reduce the internal leakage of the working fluid, and improve the performance of the compressor. You can

Next, a method of manufacturing the oil sump recess 11 formed on the tooth tip surface portion of the spiral body, which is a feature of the present invention, will be described with reference to FIG. The oil sump recess 11 has a large number of minute depressions on the tooth tips of the spiral body, and is difficult in terms of processing cost by ordinary machining such as cutting, but easy by plastic working such as coining or etching. To be produced. FIG. 5 schematically shows the case of coining as an example, in which 12 is an upper die of pressing coining and a hemispherical projection 12a is formed on the lower surface. Reference numeral 13 is a scroll material processed into the fixed scroll 1 or the orbiting scroll 2. As shown in FIG. 5A, the upper die 12 is pressed into the scroll material 13 by a press, and as shown in FIG. 5B, the protrusion 12a of the upper die 12 becomes a recess and is plastically worked. In (c), the oil sump recess 11 is processed by removing the material raised around the depression by grinding or the like.

FIGS. 6 and 7 are enlarged cross-sectional views of the tooth tip surface portion of the scroll of the fixed scroll or the orbiting scroll, showing another embodiment of the oil reservoir recess. FIG. 6 shows a substantially conical oil sump concave portion 11a. With such a shape, the volume of the depression becomes small, and the pushing force (pressing force) in plastic working can be reduced. FIG. 7 shows a substantially cylindrical oil sump recess 11b having a shape suitable for etching. With such a shape, the volume of the depression is increased, and the oil holding capacity of the oil reservoir recess 11b can be enhanced.

FIG. 8 is a plan view of an orbiting scroll showing another embodiment of the oil sump recess. FIG. 9 is a cross-sectional view of the tooth tip surface portion of the spiral body showing another embodiment of the oil sump recessed portion.
It corresponds to the III-III cross section. In this embodiment, the oil sump recess 11c is formed in a part of the tooth tip surface of the swirling spiral body 2a by an independent crosshatch-shaped oil groove that does not open to the working chamber. With such a shape, since the oil grooves communicate with each other, it is possible to improve the oil retaining capacity as compared with the embodiment shown in FIG.

In the embodiments described so far, the scroll is configured such that one scroll is fixed and the other scroll makes an orbital motion without rotating at an arbitrary turning radius. The present invention can also be applied to a double-rotating scroll compressor having a motion form equivalent to the above motion.

[0021]

According to the present invention, the working fluid is formed by forming a plurality of independent fine oil reservoir recesses that do not open to the working chamber at least in the tooth tip surface portion of one spiral body of the fixed scroll or the orbiting scroll. Lubricating oil mixed in the (refrigerant) is retained in the recesses by the capillary phenomenon to improve the lubricity, and the problems of friction and wear due to oil shortage are solved.
Further, as a result, the sealability of the tooth tip end surface portion of the spiral body is improved, the internal leakage of the working fluid can be reduced, and the performance of the compressor can be improved, and the scroll compressor corresponding to the use of the alternative refrigerant Freon 134a can be provided. Can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a scroll compressor according to the present invention.

FIG. 2 is a longitudinal sectional view of the scroll compressor according to the present invention.

FIG. 3 is a plan view of an orbiting scroll according to the present invention.

FIG. 4 is a cross-sectional view of the tooth tip surface portion of the spiral body according to the present invention, which corresponds to the II cross section of FIGS. 1 and 3;

FIG. 5 is an explanatory view of a method for manufacturing an oil sump recess formed on the tooth tip surface portion of the spiral body according to the present invention.

FIG. 6 is a sectional view of a tooth tip surface portion of another spiral body according to the present invention.

FIG. 7 is a sectional view of a tooth tip surface portion of another spiral body according to the present invention.

FIG. 8 is a plan view of another orbiting scroll according to the present invention.

FIG. 9 is a sectional view of a tooth tip surface portion of another spiral body according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fixed scroll, 1a ... Fixed scroll body, 1b ... Fixed end plate, 2 ... Orbiting scroll, 2a ... Swirl scroll body, 2b ... Swirl end plate, 3 ... Working chamber, 4 ... Suction port, 5 ... Discharge port, 11 …
Oil sump recess.

Claims (1)

[Claims] 1. A fixed scroll and an orbiting scroll, each having a spiral body of the same shape, are engaged with each other by rotating them by 180 ° so that the orbiting scroll revolves at an orbiting radius e without rotating with respect to the fixed scroll. A scroll compressor in which sliding parts are lubricated by oil, wherein a plurality of recesses are formed in a tooth tip surface portion of the spiral body of the fixed scroll and / or the orbiting scroll. ..