JPH09310687A - Scroll type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the abrasion of the thrust load support face of a scroll type compressor by an inexpensive means. SOLUTION: A groove part 6d is provided on the circumference of the back face of an end plate part 6b being one of supporting faces for thrust load acting on a movable scroll 6, and pressurized fluid is led through a communicating hole 6e which pierces the end plate part 6b from a high pressure working chamber 8a in a central part to the groove part 6d for attaining the shortest distance, and a back pressure space is formed between the flat end face part 3a of a front housing 3 being the other side of the support face and the groove part 6d to support the thrust load of the movable scroll 6. Since pressurized fluid in the groove part 6d turns into a thin film and flows out into a suction chamber 7f, a low friction thrust load supporting means supported floatingly on the fluid is therefore realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll type compressor suitable for use as a refrigerant compressor in, for example, an air conditioner for automobiles, and more particularly to improvement of thrust load supporting means in the scroll type compressor. is there.

[0002]

2. Description of the Related Art In a scroll compressor, a thrust load is inevitably applied to a movable scroll during operation due to its structural characteristics. In order to support this thrust load, the back surface of the end plate portion of the movable scroll and the flat end surface portion of a part of the housing facing the back surface are used as sliding surfaces, and they are slidably engaged. Is. In order to reduce the sliding friction on the thrust load supporting surface, for example, lubricating oil is supplied to the sliding portion of the thrust load supporting surface, or in some cases, a large number of small balls are provided between the thrust load supporting surfaces. By interposing it, sliding friction is converted into rolling friction.

However, even if such measures are taken,
When the scroll type compressor is used as a refrigerant compressor of an air conditioner, for example, liquid compression that tends to occur when the air conditioner is started in winter or insufficient lubrication causes excessive thrust load support surface. Thrust load acts or frictional sliding of the surface or rolling of the ball starts when the lubricating oil runs out, so the thrust load supporting surface receives a severe load, and the sliding or rolling surface Since a large frictional force acts on the bearing, a large amount of wear and surface roughness are generated, and as a result, there is a problem in that the thrust load supporting surface and thus the reliability of the scroll compressor are deteriorated.

As described in Japanese Utility Model Laid-Open No. 1-95584, a flat sliding contact surface is formed on the housing side at a position facing the back surface of the end plate portion of the movable scroll, and this sliding contact surface is formed. By providing a peripheral groove and introducing a part of the compressed gas taken out from the discharge port side into the peripheral groove via a passage provided on the housing side, the movable scroll is moved by the compressed gas supplied to the peripheral groove. Although a means for applying a pressing force to the peripheral groove has been proposed in this example, since the peripheral groove is provided on the housing side, not only the passage for supplying the compressed gas to the peripheral groove becomes longer, but also various parts are provided. Since it is necessary to take a complicated path that penetrates, there is a problem that the manufacturing cost of the scroll compressor increases.

[0005]

SUMMARY OF THE INVENTION The present invention addresses the above-mentioned problems in the prior art and enables a scroll type compressor to be smoothly started even in the state of liquid compression or insufficient lubrication. An object of the present invention is to provide an improved thrust load supporting means for a scroll compressor, which can improve the reliability of the scroll compressor by solving the problems of wear and surface roughness on the thrust load supporting surface. There is. Further, the present invention can suppress the increase in manufacturing cost due to the provision of the thrust load supporting means as much as possible in achieving the above-mentioned object, or avoid the increase in the size of the scroll compressor. It is also intended to provide a means by which

[0006]

The present invention provides a scroll compressor described in each of the claims as a means for solving the above problems.

In the scroll compressor according to the first aspect of the present invention, a groove portion is formed on the circumference around the center on the back surface of the end plate portion of the movable scroll which is one surface constituting the thrust load supporting surface. In addition, the groove and the high pressure working chamber are connected by a communication hole penetrating the end plate portion of the movable scroll, and a part of the fluid compressed from the high pressure working chamber is supplied to the groove during operation. Therefore, the compressed fluid is introduced into the groove portion at the shortest distance by the communication hole penetrating the end plate portion, and is formed by the groove portion and the flat end surface portion provided inside the housing as the thrust load supporting surface on the other side. By generating back pressure in the space, the movable scroll is pushed back in the axial direction against the thrust load, and the thrust load acting on the movable scroll is supported. In addition, the fluid compressed from the space of the groove flows out into the suction chamber, but at that time, since a thin fluid film is formed between the thrust load supporting surfaces, this fluid film causes the thrust load supporting surface to cause metal friction. Since the movable scroll is supported by the housing in a floating manner with respect to the thrust load without causing the friction, the friction force becomes extremely small, and the abrasion and the roughening of the thrust load supporting surface are reliably prevented.

In this case, since the communication hole for guiding the fluid compressed in the working chamber to the groove portion provided on the back surface of the end plate portion of the movable scroll is formed penetrating the end plate portion of the movable scroll, the communication hole is formed. Not only becomes the shortest length, but also the processing for providing the communication hole becomes very simple, and the increase in cost due to the process becomes slight. Moreover, since the communication hole does not penetrate other parts, it does not affect the arrangement of other parts and the design freedom of the scroll compressor is limited by the installation of the communication hole. There is no fear.

According to another aspect of the scroll compressor of the present invention, the groove portion provided on the back surface of the end plate portion of the movable scroll is formed as a plurality of arcs, and the rotation preventing mechanism substantially forms the groove portion. Since it is provided between the arcuate groove portions on the same circumference, it is not necessary to increase the barrel diameter of the scroll compressor to provide the groove portions, and the entire size can be reduced.

In the scroll compressor according to the third aspect, since the groove is formed as a single annular shape, the communication hole connecting the groove and the central high pressure working chamber is also 1 It becomes possible to make a book. Therefore, the manufacturing process for cutting or boring the groove portion and the communication hole is simplified, and the manufacturing cost is reduced.

According to another aspect of the scroll compressor of the present invention, in order to enhance the sealing property of the space formed by the groove portion provided on the back surface of the end plate portion of the movable scroll, the seal ring is provided along the peripheral edge of the groove portion. Since such a sealing material is provided, the volume efficiency of the scroll compressor is improved.

[0012]

1 and 2 show the entire structure of a scroll type compressor which is a first embodiment of the present invention. Reference numeral 1 denotes a shaft which is rotationally driven by an engine (not shown), and a crank portion 1a is formed at one end thereof. The shaft center of the crank portion 1a is eccentric by a predetermined amount with respect to the shaft center of the rotating shaft portion 1b of the other shaft 1. The shaft 1 is rotatably supported by a front housing 3 via a radial bearing 2 at its rotary shaft portion 1b. The front housing 3 is formed with a flat end surface portion 3a on the right end side, and an intake port 3b for receiving a fluid to be compressed is opened in a central space 3c for accommodating the radial bearing 2.

Inside the central space 3c, the power transmission mechanism portion 4 is attached to the crank portion 1a of the shaft 1 by means such as a spline. The power transmission mechanism section 4 includes a balance weight section 4a and a cylindrical bush section 4
It consists of b. The bush portion 4b supports the movable scroll 6 via a needle bearing 5 so as to be relatively rotatable. The movable scroll 6 has a spiral blade portion 6a.
And a disc-shaped end plate portion 6b integrated therewith, and a cylindrical boss portion 6c formed so as to project in the axial direction behind the end plate portion 6b. As described above, the bush portion 4b rotatably supports the bush portion 4b.

Corresponding to the features of the present invention, a groove portion 6d is formed on the rear surface of the end plate portion 6b of the movable scroll 6 in at least a part of the circumference of an imaginary circle centered on the boss portion 6c. The groove portion 6d is substantially closed by the flat end surface portion 3a of the front housing 3 to form a groove-shaped space, and the communication hole 6 formed by punching the end plate portion 6b.
Through e, a part of the fluid compressed by the compressor itself is supplied, so that between the back surface of the end plate portion 6b of the movable scroll 6 and the flat end surface portion 3a of the front housing 3. Further, a fluid bearing for supporting the thrust load acting on the movable scroll 6 is formed. In the first embodiment, as shown in FIG. 2, the groove portion 6d is provided as an arcuate shape whose circumference is divided into several parts, and the communication hole 6e is opened in each arcuate space.

In this case, similarly to a normal scroll compressor, a fixed scroll 7 is provided which is opposed to the movable scroll 6 at an eccentric position and meshes with the phase shifted by 180 degrees in the rotational direction. The fixed scroll 7 includes a spiral blade portion 7a having a shape similar to that of the movable scroll 6, and an end plate portion 7b integrated with the blade portion 7a. End plate 7
In b, a discharge port 7c for discharging the compressed fluid to the outside and a discharge valve port 7d opening at the center are formed in a part of the outer circumference thereof. Further, the fixed scroll 7 is provided with a housing portion 7e integrally connected to the front housing 3 by means (not shown) on the outer peripheral portion thereof, and further, two spiral blade portions 6a are provided inside the housing portion 7e. , 7a is formed on the outer peripheral side of the front housing 3, and the suction chamber 7f is formed in the central space 3 of the front housing 3.
c and the suction port 3b are always in communication.

A spiral blade portion 6a of the movable scroll 6
The fixed scroll 7 and the spiral blades 7a mesh with each other to form a plurality of crescent-shaped working chambers 8 for taking in and compressing the fluid between the spiral blades 6a, 7a. In the common central region of the two scrolls 6 and 7, only one high pressure working chamber 8a is formed in which the pressure of the compressed fluid is highest. The discharge valve port 7d formed in the end plate portion 7b of the fixed scroll 7 is positioned so as to be opened to the high pressure working chamber 8a. A bolt 9 is placed behind the end plate portion 7b of the fixed scroll 7.
The rear housing 10 is integrally attached by this. A discharge chamber 10a is formed inside the rear housing 10 and is in constant communication with the above-mentioned discharge port 7c.

Besides, in FIG. 1, 11 is a shaft 1.
A shaft seal device which is provided between the rotary shaft portion 1b and the front housing 3 to prevent the fluid to be compressed from leaking from the central space 3c of the front housing 3 to the outside.
2 is a bolt that attaches the reed check valve 13 that closes the above-described discharge valve port 7d from the discharge chamber 10a side to the end plate portion 7b together with the plate-shaped stopper 13a for limiting the valve opening amount; An example of a rotation prevention mechanism that allows the movable scroll 6 to revolve but prevents rotation is illustrated. As shown in FIG. 2, the rotation preventing mechanism 14 in this case includes the rear surface of the end plate portion 6b of the movable scroll 6 and the end surface portion 3a of the front housing 3.
Is a type that uses a plurality of pairs in which pins axially projecting from each other engage with each other, and this pair of pins is
The groove 6d formed in the end plate portion 6b of the movable scroll 6 is provided at four locations on the same circumference, avoiding the position of the groove 6d.

Since the scroll compressor of the first embodiment is constructed in this way, when the shaft 1 is rotationally driven by the engine, the movable scroll 6 will move relative to the fixed scroll 7 as in the ordinary compressor. Revolve without rotation. Therefore, when the working chamber 8 formed between the spiral blade portions 6a, 7a of the two scrolls 6 and 7 opens to the suction chamber 7f, a fluid such as a refrigerant to be compressed is taken from the suction chamber 7f, Further, the orbiting of the movable scroll 6 closes the working chamber 8, and the volume of the working chamber 8 gradually decreases while moving toward the centers of the two scrolls 6 and 7, so that the fluid in the working chamber 8 gradually increases. Compressed. When the working chamber 8 has the smallest volume and opens in the central high-pressure working chamber 8a, the fluid compressed in the working chamber 8 pushes the check valve 13 from the high-pressure working chamber 8a and the discharge valve port 7d. It opens, flows out to the discharge chamber 10a, and is guided to the outside from the discharge port 7c.

In this way the two scrolls 6 and 7
When the fluid is compressed in the working chamber 8 formed between the spiral blades 6a, 7a, a so-called thrust load Fs in the axial direction acts on the movable scroll 6 as shown in FIG. In the conventional scroll compressor, the thrust load Fs is supported by the sliding engagement between the back surface of the end plate portion 6b of the movable scroll 6 and the flat end surface portion 3a of the front housing 3 as sliding surfaces. Is normal. Then, in order to reduce such sliding friction on the thrust load supporting surface, lubricating oil is supplied or, in some cases, a large number of small balls are interposed between the thrust load supporting surfaces to convert the sliding friction into rolling friction. I am trying.

However, when the scroll type compressor is used as, for example, a refrigerant compressor of an air conditioner, as described above, in the liquid compression that tends to occur when the air conditioner is started in winter, or in the state of insufficient lubrication, , The thrust load supporting surface is subjected to excessive load, and frictional sliding of the surface and ball rolling start when the lubricating oil runs out. There is a problem that the reliability of the thrust load supporting surface is remarkably lowered due to abrasion and surface roughness.

However, in the first embodiment of the present invention, even under such a condition, the compressed fluid generated in the high pressure working chamber 8a passes through the communication hole 6e, and the end which is the thrust load supporting surface. Since the fluid is guided to the groove portion 6d formed between the back surface of the plate portion 6b and the flat end surface portion 3a, the compressed fluid is introduced from the groove portion 6d into the suction chamber 7f or the front housing 3.
When flowing out to the central space 3c of the front housing 3, a thin film of fluid is formed between the thrust load supporting surfaces and a back pressure Pf is generated in the space within the groove 6d, so that the flat end surface 3a of the front housing 3 is As with so-called fluid bearings, the movable scroll 6 is supported in a floating state with respect to the thrust load Fs, so the friction acting between the thrust load supporting surfaces is greatly reduced, and the wear and roughening of the thrust load supporting surface is ensured. To be prevented. Therefore, the reliability of the thrust load supporting surface is significantly improved.

In the scroll type compressor of the present invention,
By supplying a part of the compressed fluid between the thrust load supporting surfaces in this manner, one of them is supported in a floating state with respect to the other, so that one of the fluids compressed between the two scrolls 6 and 7 is supported. The part is consumed on the thrust load bearing surface, but the energy loss therefor is small and negligible. This is because a part of the compressed fluid supplied to the thrust load supporting surface is not discharged to the outside but immediately returns to the suction chamber 7f, so that the precompressed fluid is pressurized in the working chamber 8. This is because it will happen. FIG. 3 shows the result of trial calculation of the reduction amount of the thrust load Fs and the reduction of the volume efficiency due to the increase of the dead volume in the first embodiment.

In the example shown in FIG. 3, when a thrust load Fs of 300 kgf is applied to the orbiting scroll 6 in a normal operation state, all thrust loads Fs are balanced by the back pressure Pf to allow sliding between metal surfaces. Even if there is no dynamic friction, the reduction in volumetric efficiency due to the practice of the present invention is only about 3%. Further, in the first embodiment, since the four arc-shaped groove portions 6d in the end plate portion 6b of the movable scroll 6 are arranged on substantially the same circumference as the rotation prevention mechanism 14, the groove portion 6d is provided. There is no need to increase the barrel diameter of the scroll compressor. In order to support the movable scroll 6 in a well-balanced manner with respect to the thrust load Fs, it is preferable to arrange the three to four arc-shaped groove portions 6d evenly distributed around the boss portion 6c.

Therefore, according to the first embodiment of the present invention, the reliability of the thrust load bearing surface can be improved even in a severe operating condition where liquid compression or insufficient lubrication occurs such as when the air conditioner is started in winter. It is possible to provide a small scroll type compressor that can be sufficiently secured.

FIG. 4 shows a main part of a scroll type compressor as a second embodiment of the present invention. In the first embodiment,
Between the back surface of the end plate portion 6b of the movable scroll 6, which is one of the thrust load supporting surfaces, and the flat end surface portion 3a of the front housing 3, which is the other, a circular arc shape formed on the back surface of the end plate portion 6b. It may be said that no special seal is provided around the groove 6d and that it depends on a lubricating oil component such as refrigerating machine oil contained in a fluid such as a refrigerant to be compressed. In the second embodiment, the groove 6d
In order to improve the sealing performance of the space 15 formed by the above, a characteristic is that a seal ring 16 molded from a material such as synthetic resin is provided so as to be fitted along the peripheral edge of the arc-shaped groove portion 6d. As a result, the same effect as that of the first embodiment can be obtained, and the volumetric efficiency of the scroll compressor can be further enhanced.

FIG. 5 shows a main part of a scroll type compressor as a third embodiment of the present invention. This embodiment focuses on reducing the cost as compared with the above-described embodiments, and the groove portion 6d formed on the back surface of the end plate portion 6b of the movable scroll 6 is shown in FIG. 2 and FIG. It is characterized in that it has a single annular shape without being divided into a plurality of arc-shaped portions, and that it has only one communication hole 6e communicating with the high-pressure working chamber 8a. Thereby, the groove 6d
It is possible to reduce the processing cost for cutting or boring the communication hole 6e as compared with other embodiments. The dashed circle 17 in FIG. 5 indicates the outer circumference of the movable scroll 6.

However, if the groove portion 6d is formed in a continuous annular shape as described above, the groove portion 6d cannot be provided on substantially the same circumference as the rotation preventing mechanism 14 as in the above-described embodiments. , As illustrated in FIG.
It is necessary to move the rotation preventing mechanism 14 to the inside of the groove 6d or to provide the rotation preventing mechanism 14 at an appropriate position outside the groove 6d. In some cases, it may be necessary to increase the barrel diameter of the scroll compressor. Therefore, although it is somewhat disadvantageous in this respect, the same effect as in the case of the first embodiment can be obtained at low cost. Furthermore, by using another suitable type of rotation preventing mechanism 14, the boss portion 6c of the movable scroll 6 is prevented.
It is also possible to provide a rotation prevention mechanism at a position close to.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view showing the overall configuration of a scroll compressor according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional side view of the first embodiment.

FIG. 3 is a diagram illustrating an example of a result of trial calculation of a decrease in volumetric efficiency according to implementation of the present invention.

FIG. 4 is a cross-sectional side view showing a main part of the second embodiment.

FIG. 5 is a transverse side view showing a main part of the third embodiment.

[Explanation of symbols]

 3 ... Front housing 3a ... Flat end face part 3b ... Suction port 3c ... Central space 4b ... Bushing part 5 ... Needle bearing 6 ... Movable scroll 6a ... Spiral blade part 6b ... End plate part 6c ... Boss part 6d ... Groove part 6e ... Communication hole 7 ... Fixed scroll 7a ... Spiral blade part 7b ... End plate part 7c ... Discharge port 7d ... Discharge valve port 7f ... Suction chamber 8 ... Working chamber 8a ... High pressure working chamber 10 ... Rear housing 10a ... Discharge chamber 13 ... Check valve 15 ... Space 16 ... Seal ring

Claims (4)

[Claims] 1. A fixed scroll forming a part of the housing, which has a suction chamber and a discharge chamber respectively formed in the housing, a spiral vane portion formed on a fixed end plate portion, and a movable scroll. Movable scroll having spiral blades formed on the end plate of the scroll and engaging with the fixed scroll to form a plurality of working chambers for compressing a fluid between the spiral blades. A check valve as a discharge valve provided between the high pressure working chamber and the discharge chamber, which is formed in common in the center of the two scrolls, and allows the movable scroll to revolve and prevent rotation. A rotation preventing mechanism provided between the housing and the movable scroll, and a flat end surface portion formed inside the housing and the back surface of the end plate portion of the movable scroll. A thrust load supporting surface, a groove portion formed around the center of the movable scroll on the back surface of the end plate portion of the movable scroll, and the end plate for connecting the groove portion and the high pressure working chamber in the shortest distance. A scroll type compressor having a communication hole formed by penetrating the portion. 2. The groove portion is formed as a plurality of arc-shaped ones, and the rotation preventing mechanism is provided between the arc-shaped groove portions on substantially the same circumference as the groove portion. The scroll type compressor according to claim 1, wherein the scroll type compressor is provided. 3. The groove portion is formed as a single annular shape, and the rotation preventing mechanism is provided at different positions in the radial direction with respect to the groove portion. Scroll compressor. 4. The scroll according to claim 1, wherein a sealing material is provided along a peripheral edge of the groove portion in order to enhance a sealing property of a space formed by the groove portion. Type compressor.