JPH0350308Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a scroll type compressor for vehicle air conditioning, especially a scroll type compressor equipped with a ball-based mechanism to prevent the movable scroll from rotating. This invention relates to a mechanism for reducing compression capacity, that is, a variable compression capacity mechanism.

[Conventional technology]

Generally, in a scroll type compressor, a fixed scroll formed in a spiral shape and a movable scroll also formed in a spiral shape are provided so as to interlock with each other, and the movable scroll slides into contact with the fixed scroll while oscillating and rotating. (revolution) to obtain a compression effect. More specifically, the movable scroll is oscillated and rotated in a state in which it is constantly in sliding contact with the fixed scroll at at least two places, that is, the movable scroll is oscillated and rotated in a state in which its rotation is restricted. By doing so, a sealed compression space is formed between both scrolls, and the compression space is gradually made smaller toward the center of the spiral, thereby obtaining a compression effect. A rotation prevention mechanism using balls has previously been proposed as a method for swinging and rotating a movable scroll while its rotation is restricted. (Japanese Unexamined Patent Publication No. 57-148087) Fig. 10 is a drawing showing the specific structure, in which a fixed scroll b is fixed in a housing a, and a movable scroll c swings in opposition to the fixed scroll b. The scrolls b and c are mounted rotatably on a shaft and are interlocked with each other so that they are in sliding contact at at least two locations. And movable scroll c and housing a
A pair of rings d and e are provided facing each other on the inner wall surface of the ring, in which a large number of circular depressions f and g are formed along the circumferential direction.
A ball h is freely rotatably engaged therebetween.

[Problem that the invention attempts to solve]

However, since the compressor for vehicle air conditioning is connected to the engine at a constant rotation ratio, when the electromagnetic clutch is connected to operate the compressor, the compressor is connected at the same time as the electromagnetic clutch is connected. A state in which refrigerant gas is discharged at the full compression capacity given to the machine, that is, at the same time as startup.
This allows a 100% operating state to be obtained at the same time as the startup, so that the power transmission mechanism such as the engine and the compressor are In addition to causing the problem of applying shock to various parts of the vehicle, when the cooling load in the vehicle cabin decreases, the compression capacity cannot be reduced in response to the change, in other words, the electromagnetic clutch is disengaged. Otherwise, there is a problem in that the compression capacity cannot be reduced.

In addition, in a scroll type compressor, a method for alleviating the impact that occurs on the engine and various parts of the compressor when the compressor is started is to create a state in which the movable scroll piece does not come into sliding contact with the fixed scroll piece when the compressor is stopped. In other words, a gap is formed between both scroll pieces and no compression space is formed, and the movable scroll piece is oscillated (revolving) in such a state that no compression space is formed. Therefore, a method has been proposed in which a compression effect is not obtained during startup, in other words, a method in which the movable scroll pieces are oscillated and rotated at a revolution radius smaller than that in normal operating conditions (JP-A (No. 58-67903) However, in this proposal, since the spring is interposed in the large diameter part formed at the tip of the main shaft, the installation space for the spring is limited, and it is difficult to properly install the spring. In addition to making it difficult to insert a spring, the spring is compressed almost instantaneously when the set rotation speed is reached, that is, when the centrifugal force exceeds the biasing pressure of the spring. In other words, there is a problem in that accurate assembly precision is required, and in addition, an effective reduction in capacity cannot be obtained.

This invention is an attempt to improve the above-mentioned problems by making it possible to temporarily release some of the refrigerant gas that is in the middle of compression to the low pressure side. The problem to be solved lies in making it possible to reduce the compression capacity. That is, the present invention is a scroll type compressor equipped with a ball-based mechanism for preventing rotation of the movable scroll, in which the movable scroll, which is provided so as to be able to freely swing and rotate (revolution) by engaging the fixed scroll, is moved forward and backward through the pressure difference within the compressor. By moving and changing the orbital radius of the movable scroll, a gap is formed between the tip and peripheral surface of both scroll pieces, and a part of the refrigerant gas that is being compressed is released to the low pressure side through this gap. The specific means and effects are as follows.

[Means for solving problems]

A scroll piece of a fixed scroll in which a crankshaft part is formed at one end of a drive shaft horizontally mounted on the housing, a movable scroll is rotatably mounted on the crankshaft part, and the scroll piece of the movable scroll is fixed to the housing. At the same time, a pair of rings formed by arranging a large number of circular grooves along the circumferential direction are placed facing each other on the inner wall surfaces of the movable scroll and the housing, and a ball is inserted between each pair of facing circular grooves. In a scroll type compressor which is provided with a mechanism to prevent rotation of a movable scroll by engaging the movable scroll, the movable scroll is mounted on a shaft such that it can move forward and backward with respect to a crankshaft part and the center of rotation can be slightly deviated.

A pressure action chamber is provided on the front surface of the movable scroll in correspondence with the rotation prevention mechanism of the movable scroll, and the same pressure action chamber is selected for the high pressure side of the discharge chamber or compression chamber and the low pressure side of the suction chamber or compression chamber. be installed so that they can communicate with each other.

[Operation] By communicating the pressure chamber with the high-pressure side of the discharge chamber or compression chamber and feeding discharge gas or high-pressure gas in the middle of compression into the pressure chamber, the movable scroll is pressed toward the fixed scroll side, and both A state is obtained in which the tips of the scroll pieces are in close contact with each other, and a state in which the movable scroll oscillates with a large revolution radius is obtained in the rotation prevention mechanism using balls, and as a result, the circumferential surfaces of both scroll pieces are in close contact with each other. The state is obtained. That is, a normal operating state is obtained. In addition, by communicating the pressure chamber with the low pressure side of the suction chamber or compression chamber and feeding suction gas or low pressure gas in the middle of compression into the pressure chamber, the movable scroll is separated from the fixed scroll, and the tips of both scroll pieces are A state is obtained in which a gap (thrust gap) is formed between the two scroll pieces, and a state is also obtained in which the movable scroll oscillates with a small revolution radius in the rotation prevention mechanism using balls, and as a result, a gap is formed between the circumferential surfaces of both scroll pieces. A state is obtained in which a gap (radial gap) is formed. That is, a part of the refrigerant gas that is being compressed is released to the low pressure side, thereby achieving the effect of reducing the compression capacity.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to the illustrative drawings.

In each drawing shown in FIGS. 1 to 9, 1
indicates the housing that constitutes the outer shell of the compressor. The housing 1 is made up of a front housing 2 and a rear housing 3, and the front housing 2 has a front wall portion 2a and a peripheral wall portion 2b surrounding the outer periphery of the front wall portion 2a, and is formed into a cylindrical shape with a bottom. . The rear housing 3 also has a rear wall portion 3a and a rear wall portion 3a.
It is formed into a bottomed cylindrical shape with a peripheral wall portion 3b surrounding the outer periphery of a. That is, the housing 1 is constructed by integrally joining the openings of a front housing 2 and a rear housing 3, which are formed in a cylindrical shape with a bottom, through screwing with bolts and nuts (not shown). A fixed scroll 4 is fitted into the rear housing 3 at a substantially intermediate portion thereof. The fixed scroll 4 includes a base 4a formed in a disk shape and a scroll piece 4b spirally protruding from the base 4a toward two directions (forward) of the front housing.
A suction chamber 5 and a discharge chamber 6 are formed concentrically between the base plate 4a and the rear wall portion 3a of the rear housing 3. That is, a discharge chamber 6 is provided at the center, and a suction chamber 5 is provided at the outer periphery so as to surround the discharge chamber 6. The rear wall portion 3a of the rear housing 3 has a suction port 7 that communicates with the suction chamber 5 and is connected to a suction pipe (not shown).
A discharge port 8 that communicates with the discharge chamber 6 and connects to a discharge pipe line (not shown) is opened. Furthermore, as will be described later, scroll pieces 9b of the movable scroll 9 are provided on the scroll piece 4b of the fixed scroll 4 so as to engage with each other, and a compression chamber 10 is formed between the scroll pieces 4b and 9b. And the same compression chamber 10
The outer circumferential portion of the compression chamber 10 communicates with the suction chamber 5 through a suction hole 5' opening in the base 4a, and the central portion of the compression chamber 10 communicates with the discharge chamber 6 through a discharge hole 6' opening in the base 4a. A discharge valve 11 is attached to the discharge port 8 so as to be openable and closable. Sho 1
2 indicates a retainer for regulating the opening angle of the discharge valve 11.

On the other hand, a pressure acting chamber 13 is formed in the front housing 2 adjacent to the aforementioned compression chamber 10, and a boss 14 is integrally provided on the front wall 2a of the front housing 2 and protrudes from the center thereof. The drive shaft 1 is connected to the boss 14 via a pair of bearings 15 and 16 and a mechanical seal 17.
8 is rotatably supported. The drive shaft 18 has one end protruding outside the front housing 2 and connected to an electromagnetic clutch (not shown), while the other end faces the pressure chamber 13 and a balance weight 19 is mounted thereon. A crankshaft portion 20 is also provided. The above-mentioned movable scroll 9 is rotatably mounted on the crankshaft portion 20 via an eccentric bush 20'. That is, the movable scroll 9 has a base 9a formed in a disk shape, and a fixed scroll 4 from the base 9a.
The scroll piece 9 consists of a scroll piece 9b that protrudes spirally in the direction (rearward direction) and a bearing cylinder 9c that protrudes forward from the base plate 9a.
b is provided so as to be able to swing and rotate while slidingly contacting the scroll piece 4b on the fixed scroll 4 side at least at two or more places. Furthermore, the scroll piece 9b can freely move back and forth in the front and rear directions with respect to the scroll piece 4b on the fixed scroll 4 side, and the swing radius can be changed over a minute range via the eccentric bush 20'. provided as possible. That is, the scroll piece 9b on the side of the movable scroll 9 is provided so as to be able to move toward and away from the base 4a and the scroll piece 4b on the side of the fixed scroll 4, respectively. Further, an annular groove 21 is formed on the outer peripheral portion of the base 4a of the fixed scroll 4 so as to face the base 9a on the movable scroll 9 side. And the same annular groove 2
1, a seal piece 22 is inserted into the annular groove 21 so as to be freely retractable, and a spring 23 is interposed in the annular groove 21.
is provided so as to be in constant pressure contact with the base 9a on the movable scroll 9 side through the biasing action of the spring 23.

Further, a rotation prevention mechanism for the movable scroll 9 is provided in the pressure chamber 13 . That is, a movable ring 24 is fixed to the front side of the base 9a of the movable scroll 9, and a large number of circular grooves 24' are formed in the movable ring 24, while the front housing 2
A fixed ring 25 is fixed to the movable ring 24 so as to face the movable ring 24, and the fixed ring 25 is similarly provided with a number of circular grooves 25'. A ball 2 is placed between each pair of circular grooves 24' and 25' facing each other.
6 is freely rotatably engaged.

Further, a pressure guiding path 27 is extended from the same pressure action chamber 13, and a switching valve 28 is provided at the tip thereof, and a plurality of pressure guiding paths 27a and 27b are branched and extended from the switching valve 28, One pressure guide path 27a is provided to communicate with the suction chamber 5, and the other pressure guide path 27b is provided to communicate with the discharge chamber 6, respectively.

Next, its effect will be explained.

In FIG. 1, the pressure channel 2 is
7 and the pressure guiding path 27b are in communication, that is, the discharge chamber 6 and the pressure action chamber 13 are in communication. The discharge pressure in the discharge chamber 6 is sent into the pressure action chamber 13, and a state is obtained in which the movable scroll 9 is pressed toward the fixed scroll 4 by the discharge pressure. As the movable scroll 9 is pressed in the direction of the fixed scroll 4 in this way, the tip of the scroll piece 9b on the movable scroll 9 side touches the base 4a on the fixed scroll 4 side, and the scroll piece 9b on the fixed scroll 4 side On the one hand, the distal end portions of the movable ring 24 and the fixed ring 25 are in close contact with the base 9a on the movable scroll 9 side.
A state in which the balls 26 engaged between each pair of circular grooves 24' and 25' carved in the grooves rotate with a large radius R, that is, the movable scroll 9 moves its scroll piece 9b toward the fixed scroll 4 side. Scroll piece 4b
A state of rocking rotation (revolution) can be obtained with parts in close sliding contact at at least two places. And like this, both scroll pieces 4
The movable scroll 9 swings while the tip portions of the scroll pieces 4b, 9b are in close contact with the opposing bases 9a, 4a, and the circumferential surfaces of both the scroll pieces 4b, 9b are in close sliding contact at at least two places. By rotating (revolving), the normal compression state (100%
operation status) is obtained.

In addition, at the time of startup, during liquid compression, or in a state where the vehicle interior is over-cooled, the valve 28 is switched so that the pressure guide path 27 and the pressure guide path 27a communicate with each other,
That is, a state is obtained in which the suction chamber 5 and the pressure action chamber 13 communicate with each other. Since the suction chamber 5 and the pressure chamber 13 are in communication with each other in this way, a pressure difference is created between the pressure chamber 13 and the compression chamber 10, and this pressure difference causes the movable scroll 9 to move into the pressure chamber 13. A state of moving backward to the side is obtained. As the movable scroll 9 moves backward toward the pressure action chamber 13 in this manner, a gap (thrust gap C ) is formed, while the distance between the fixed ring 25 and the movable ring 24 is narrowed, and the balls 26 that engage between each pair of circular grooves 24', 25' carved in both rings 24, 25 have a small radius. In other words, a gap (radial gap) exists between the scroll piece 9b of the movable scroll 9 and the scroll piece 4a on the fixed scroll 4 side.
C′), and a state of oscillating rotation (revolution) is obtained. In this way, there is a thrust gap C between the tip ends of both scroll pieces 4b, 9b and the opposing bases 9a, 4a, and a radial gap C' between the circumferential surfaces of both scroll pieces 4b, 9b. When the movable scroll 9 rotates (revolutions), a part of the refrigerant gas that is being compressed is released to the low pressure side, that is,
It has the effect of reducing cooling capacity.

The thrust gap C and the radial gap C' are set within a range where a compression effect can be obtained and the differential pressure necessary to move the movable scroll 9 forward and backward can be secured. Moreover, the pressure sent into the pressure action chamber 13 is not limited to the discharge pressure and the suction pressure, and it is also possible to send pressure in the middle of compression.

[Effect of idea]

The present invention is constructed as described above, and is a scroll type compressor equipped with a mechanism for preventing rotation of a movable scroll using balls as described above, which can freely swing and rotate (revolution) by engaging a fixed scroll.
By moving the movable scroll installed in the compressor forward and backward through the pressure difference within the compressor and changing the orbital radius of the movable scroll, a gap is formed between the tip and circumferential surface of both scroll pieces, and through this gap By making it possible to release a portion of the refrigerant gas during compression to the low pressure side, it has become possible to obtain the effect of reducing the compression capacity with a simple structure. By allowing part of the refrigerant gas that is being compressed to escape to the low pressure side in this way, it is possible to alleviate the impact during startup and liquid compression, and also to prevent the electromagnetic clutch from overheating in the event of excessive cooling. It has now become possible to reduce the capacity in stages without cutting off the battery.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing the entire scroll type compressor according to the present invention, FIG. 2 is a side sectional view showing the same operating state, FIG. 3 is a sectional view taken along line A-A in FIG. 5 and 5 are enlarged cross-sectional views of the main parts showing the operating state of the rotation prevention mechanism part of the movable scroll, and Figs. 6 to 9 are enlarged views of the main parts showing the operating state of the interlocking part of the movable scroll and the fixed scroll. FIG. Further, FIG. 10 is a drawing showing a conventional structure, and is a side sectional view showing the entire scroll type compressor equipped with a rotation prevention mechanism using balls. DESCRIPTION OF SYMBOLS 1...Housing, 2...Front housing, 2a...Front wall part, 2b...Peripheral wall part, 3...Rear housing, 3a...Rear wall part, 3b...Peripheral wall part, 4...Fixed scroll, 4a ...Foundation, 4b
...Scroll piece, 5...Suction chamber, 5'...Suction hole, 6...Discharge chamber, 6'...Discharge hole, 7...Suction port, 8...Discharge port, 9...Movable scroll, 9a
...Base, 9b...Scroll piece, 9c...Bearing cylinder, 10...Compression chamber, 11...Discharge valve, 12...
...retainer, 13...pressure action chamber, 14...boss, 15...bearing, 16...bearing,
17... Mechanical seal, 18... Drive shaft, 19... Balance weight, 20... Crankshaft section, 20'... Eccentric bushing, 2
1... Annular groove, 22... Seal piece, 23... Spring, 24... Movable ring, 24'... Circular groove, 2
5...Fixing ring, 25'...Circular groove, 26...
Ball, 27, 27a, 27b... Pressure path, 28
...Switching valve.

Claims (1)

[Scope of utility model registration request] A fixed scroll in which a crankshaft part is formed at one end of a drive shaft horizontally mounted on the housing, a movable scroll is rotatably mounted on the crankshaft part, and a scroll piece of the movable scroll is fixed to the housing. A pair of rings formed by disposing a large number of circular grooves along the circumferential direction are arranged facing each other on the inner wall surfaces of the movable scroll and the housing, and a ball is inserted between each pair of circular grooves facing each other. In a scroll type compressor which is provided with a rotation prevention mechanism for the movable scroll by engaging the movable scroll, the shaft frame is arranged such that the movable scroll can move forward and backward with respect to the crankshaft part and the center of rotation can be slightly deviated. On the other hand, a pressure action chamber is provided on the front surface of the movable scroll in correspondence with the rotation prevention mechanism, and the same pressure action chamber is selected for the high pressure side of the discharge chamber or compression chamber and the low pressure side of the suction chamber or compression chamber. A variable compression capacity mechanism in a scroll compressor, which is configured to be able to communicate with each other.