JPH0799155B2 - Variable capacity scroll compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fixed scroll housed in a housing,
The present invention relates to a variable capacity scroll type compressor that forms a closed space whose volume is reduced based on the revolution of a movable scroll between a movable scroll that is non-rotatably and revolvable so as to face the fixed sroll, and is particularly used for automobile cooling. The present invention relates to a variable capacity scroll type compressor suitable for a compressor used in an apparatus.

[Prior Art] A variable displacement scroll compressor shown in FIG. 4 is disclosed in Japanese Patent Laid-Open No. 60-101295. This scroll compressor is provided with bypass holes 43, 44 at a position closer to the inside than the outermost end of the spiral portion 42 of the fixed scroll 41, and connects the bypass holes 43, 44 and the suction chamber 45 with a check valve 46. An intermediate pressure chamber (bypass chamber) 47 communicating via the intermediate pressure chamber 47 and the intermediate pressure chamber 47 for selectively connecting the intermediate pressure chamber 47 and the suction chamber 45.
An opening / closing valve mechanism 48 for controlling the amount of discharge gas introduced from the discharge chamber 50 via a conduit 49 for operating the opening / closing valve mechanism 48 provided on the output side of 47. Is opened and closed to control the pressure in the intermediate pressure chamber 47, thereby opening and closing the check valve 46 and increasing the compression capacity when the on-off valve mechanism 48 is closed.

[Problems to be Solved by the Invention] However, in the conventional compressor, the control of the on-off valve mechanism 48 for opening and closing the check valve 46 is performed by turning on and off the discharge pressure introduction using the solenoid valve 51. There is a problem that the structure becomes complicated. In addition, in the variable mechanism that uses the bypass passage, when the rotation speed of the compressor is in the high speed region, the closed space whose volume is decreasing momentarily passes through the inlet of the bypass passage. Compared to the case of 1, the refrigerant gas is less likely to be returned to the suction pressure region via the bypass passage. Therefore, when used in a vehicle air conditioner,
During high-speed operation, the variable bypass effect does not work so much that the engine is cooled too much, and the only way to prevent overcooling is to disengage the clutch that transmits the rotation of the engine to the drive shaft and stop the operation of the compressor. Preventing supercooling by turning the clutch on and off not only makes the variable capacity meaningless, but also has the disadvantage that the driving feeling of the vehicle deteriorates. If the inlet of the bypass passage is enlarged in order to enhance the variable effect in the high speed region, the amount of refrigerant gas recirculation in the low speed region becomes too large and the variable effect becomes too effective. If the introduction port of the bypass passage is made smaller for the purpose of optimization, there is a problem that the variable effect in the high speed region becomes small.

The present invention has been made in view of the above problems,
It is an object of the present invention to provide a variable capacity scroll compressor capable of providing an appropriate variable effect in the entire range from low speed to high speed.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a fixed scroll housed in a housing, and a movable scroll provided so as to be non-rotatable and revolvable so as to face the fixed scroll. In a scroll-type compressor that forms a closed space whose volume decreases due to the revolution of the orbiting scroll, a spool that is operated based on the refrigerant gas pressure is provided on the introduction passage for introducing the refrigerant gas into the compressor. A suction throttle mechanism that can change the passage cross-sectional area is provided, and the base end of the fixed scroll is located at a position corresponding to the volume decreasing region of the closed space that moves to the center side of the spiral part erected at the lower end of the base end of both scrolls. A bypass hole that penetrates the wall and communicates with a bypass chamber provided on the back side of the fixed scroll is provided, and the bypass chamber and the suction throttle mechanism are connected by a pipe line. In addition, the suction throttle mechanism is provided with a passage that allows the pipe to communicate with the suction pressure region when the spool moves in a direction that reduces the passage cross-sectional area of the suction gas passage.

[Operation] In the variable mechanism by opening / closing the bypass, the variable effect decreases as the rotational speed increases, whereas in the suction throttle mechanism, the passage resistance of the refrigerant gas increases and the variable effect increases as the rotational speed increases. According to the present invention, when the cooling load is large, the spool of the suction throttle mechanism moves in a direction of increasing the passage cross-sectional area of the introduction passage, and at this time, the pipeline connecting the bypass chamber and the suction throttle mechanism is in a state of communication with the suction pressure region. Is blocked. In this state, the bypass hole is closed and the variable bypass mechanism has the maximum capacity. On the other hand, when the cooling load is small, the spool of the suction throttle mechanism moves in the direction in which the passage cross-sectional area of the introduction passage decreases, and at this time, the pipe line connecting the bypass chamber and the suction throttle mechanism is in communication with the suction pressure region. In this state, the compressed gas can be bypassed from the bypass hole. Then, the variable action of the suction throttle mechanism works effectively in the high speed region, and the variable action of the bypass mechanism works effectively in the low speed region. That is, the two mechanisms mutually compensate for the variable action in the rotation speed region where the respective variable effects are difficult to be exerted, and an appropriate variable action is performed in the entire region from the low speed region to the high speed region.

[First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the front housing 1 and the rear housing 2 are joined and fixed by sandwiching an annular fixed substrate 3, and a large diameter portion 4a of a rotary shaft 4 housed in the front housing 1
An eccentric shaft 5 is projectingly provided in the rear housing 2.
A balance weight 6 and a bush 7 are rotatably supported on the eccentric shaft 5, and a movable scroll 8 is rotatably supported on the bush 7. A fixed scroll 9 is accommodated and fixed in the rear housing 2 in a state of facing the movable scroll 8, and the base end walls 8a and 9a of both scrolls 8 and 9 and the spiral portion 8 are provided.
A closed space (compression space) P is formed by b and 9b.

A fixed ring 10 is fixed to the fixed base plate 3 facing the movable scroll 8, and a plurality of circular revolution position restriction holes 10a are formed in the fixed ring 10 at equal intervals. On the back surface of the base wall 8a of the orbiting scroll 8, the revolution position regulating hole 10 is formed.
A movable ring 11 having the same number of circular revolution position restricting holes 11a facing the a is fixed. Revolution position control hole 10
Disc-shaped shoes 12a and 12b having a smaller diameter than that are accommodated in a and 11a, and a ball 13 is interposed between the opposing shoes 12a and 12b. The shoes 12a and 12b and the ball 13 are pressed and fitted between the fixed base plate 3 and the movable scroll 8 by a compression reaction, and are apparently integrated. Then, as shown by the chain line in FIG. 2, all the shoes 12a, 12b circulate around the periphery of the revolution position regulating holes 10a, 11a in the same direction while being sandwiched between the revolution position regulating holes 10a, 11a by the revolution of the eccentric shaft 5. However, the movable scroll 8 revolves around its axis without rotating.

The front housing 1 is formed with an introduction passage 14 for introducing a refrigerant gas into the suction chamber 1a, and the fixed substrate 3 is provided with a suction chamber.
A passage 3a is formed for guiding the refrigerant gas introduced into 1a between the scrolls 8 and 9. At the center of the base end wall 9a of the fixed scroll 9, there is formed a discharge port 9c which communicates with a discharge chamber 15 provided on the back side of the base end wall 9a and which is openably closed by a discharge valve 16. . A bypass chamber 17 is formed on the rear side of the fixed scroll 9 so as to be separated from the discharge chamber 15, and the base end wall 9a of the fixed scroll 9 is spirally erected on the base end walls 8a and 9a of both scrolls 8 and 9. A bypass hole 18 communicating with the bypass chamber 17 is formed at a position corresponding to the volume decreasing region of the closed space P that moves to the center side of the portions 8b and 9b. A check valve 19 is arranged in the bypass chamber 17 so that the bypass hole 18 can be opened and closed.

A suction throttle mechanism 20 is arranged on the introduction passage 14. The housing 21 of the suction throttle mechanism 20 is formed with an introduction portion 21a which is orthogonal to the introduction passage 14 and also serves as a storage portion for storing the spool 22, and a storage chamber 21b which is continuous with the introduction portion 21a. The communication passage 21c communicates with the introduction passage 14. A spool 22 is slidably accommodated in the introduction portion 21a at a position corresponding to the communication portion 21c, and the accommodation chamber 21
The spring 23 interposed in the b b urges the communicating portion 21 c in the direction of decreasing the passage cross-sectional area. The spring 23 is interposed between the pair of spring bearings 24a and 24b, and the biasing force can be adjusted by changing the position of one spring bearing 24a with the adjusting screw 25.

Further, the bypass chamber 17 and the suction throttle mechanism 20 are connected by a pipe line 26, and the housing 21 of the suction throttle mechanism 20 has a through hole 27a for communicating the pipe line 26 and the introduction portion 21a, and the suction portion 21a. A through hole 27b that communicates with the introduction passage 14 as a pressure region is formed, and the spool 22 allows the two through holes 27a and 27b to communicate with each other when the spool 22 moves in a direction that reduces the passage cross-sectional area of the communication portion 21c. A bypass passage 28 is formed. Both through holes 27a, 27
The b and the bypass passage 28 form a passage that communicates the pipeline 26 with the suction pressure region.

Next, the operation of the compressor configured as described above will be described.

When the spiral portion 8b of the orbiting scroll 8 revolves clockwise in FIG. 2 while locally contacting the spiral portion 9b of the fixed scroll 9 as the rotary shaft 4 rotates, the contact portions of both spiral portions 8b, 9b are The closed space P which moves toward the center on the inner peripheral surface of the spiral portion 9b and is formed between the two contact portions gradually compresses the refrigerant gas introduced into the compressor from the introduction passage 14 and gradually moves toward the center side. The moved and compressed refrigerant gas is discharged into the discharge chamber 15 from the discharge port 9c which is openably closed by the discharge valve 16.

When the cooling load is high and the suction pressure is high, the spool 22
Is held at the maximum capacity position where the passage cross-sectional area of the communication portion 21c is maximized against the biasing force of the spring 23. In this state, the bypass passage 28 of the spool 22 is in a state where the communication with both the through holes 27a and 27b is blocked, that is, the bypass passage 28 is closed, and the refrigerant gas in the bypass chamber 17 passes through the pipe line 26. It is in a state where it cannot flow back into the introduction passage 14 as the suction pressure region. Therefore, the check valve 19 is held in a position to close the bypass hole 18, and the compressor is operated at the maximum capacity.

On the contrary, when the suction pressure becomes small, that is, when the cooling load is small, the spool 22 is held at the throttle position where the passage cross-sectional area of the communication portion 21c becomes small by the urging force of the spring 23 as shown in FIG. In this state, the bypass passage 28 of the spool 22 is in communication with both the through holes 27a and 27b, that is, the bypass passage 28 is open, and the refrigerant gas in the bypass chamber 17 has the pipeline 26, the through hole 27a, and the bypass passage 28. It is in a state where it can flow back to the introduction passage 14 as a suction pressure region through the through hole 27b. Then, when the compressor is operated in the high speed region in this state, the capacity reducing action through the bypass hole 18 constituting the bypass variable mechanism is small, but the capacity reducing action by the throttle effect of the spool 22 is effective. work. On the other hand, when the compressor is operated in the low speed region, the capacity reducing action due to the throttling effect of the spool 22 decreases, but the capacity reducing action via the bypass hole 18 works effectively. That is, the suction throttle mechanism and the bypass variable mechanism compensate each other for the variable action in the rotation speed region where it is difficult to exert the respective variable effects, and the appropriate variable action is performed in the entire region from the low speed region to the high speed region. Therefore, when used in a vehicle air conditioner, it is not necessary to stop the operation of the compressor by disengaging the clutch that transmits the rotation of the engine to the rotating shaft 4 due to excessive cooling during high-speed operation. It is possible to surely avoid the inconvenience that the driving feeling of the vehicle is deteriorated due to the impact.

Further, since the means for operating the suction throttle and the variable bypass mechanism is composed of one spool 22, the structure becomes simple.

The present invention is not limited to the above embodiment,
For example, as shown in FIG. 3, by increasing the diameter of the through hole 27a formed in the absorption throttle mechanism 20 or by making it into a long hole, the action of the bypass variable mechanism is achieved even in the middle of the movement of the spool 22 toward the large capacity side. By expanding the possible area to adjust the bypass amount, the front housing 1 and the suction throttle mechanism can be adjusted.
The housing 21 of 20 may be integrally formed, or the through hole 27b may be communicated with another suction pressure region instead of being communicated with the introduction passage 14.

[Effects of the Invention] As described in detail above, according to the present invention, the variable action of the suction throttle mechanism in the high speed range and the variable action of the bypass mechanism in the high speed range work effectively, and both mechanisms have their respective functions. Muting the variable effects in the rotation speed range where the variable effect is difficult to exert mutually compensates for each other, and the appropriate variable effects are performed in the entire range from the low speed range to the high speed range. It is no longer necessary to operate the compressor by disengaging the clutch that transmits the rotation of the engine to the rotating shaft and stopping the operation of the compressor. To be avoided. Further, since the bypass opening / closing mechanism and the suction throttle mechanism are interlocked and controlled by one spool, the structure of the capacity varying mechanism is simplified and the device can be downsized.

[Brief description of drawings]

1 and 2 show a first embodiment embodying the present invention. FIG. 1 is a sectional view, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. FIG. 4 is a sectional view of an example suction throttle mechanism, and FIG. 4 is a partial sectional view of a conventional device. Front housing 1, suction chamber 1a, rear housing 2,
Movable scroll 8, fixed scroll 9, base end walls 8a, 9a,
Spiral parts 8b, 9b, introduction passage 14, bypass chamber 17, bypass hole 1
8, suction throttle mechanism 20, introduction part 21a, accommodation chamber 21b, communication part 21
c, spool 22, spring 23, pipe line 26, through hole 2 forming the passage
7a, 27b and bypass passage 28, closed space P.

Claims (1)

[Claims] 1. A hermetically sealed space, which is reduced in volume based on the revolution of a movable scroll, is provided between a fixed scroll housed in a housing and a movable scroll that is provided so as to be non-rotatable and revolvable so as to face the fixed scroll. In the scroll compressor to be formed, an intake throttle mechanism whose passage cross-sectional area can be changed by a spool operated based on the refrigerant gas pressure is provided on an introduction passage for introducing refrigerant gas into the compressor, and both scrolls are provided. Bypass chamber that penetrates the base end wall of the fixed scroll and is provided on the back side of the fixed scroll at a position corresponding to the volume decreasing region of the closed space that moves to the center side of the spiral portion erected on the base end wall of the fixed scroll. A bypass hole communicating with the bypass chamber is provided, and the bypass chamber and the suction throttle mechanism are connected by a pipe line. The spool has a passage cross-sectional area of the suction gas passage in the suction throttle mechanism. Variable displacement scroll type compressor provided with a passage communicating the suction pressure region of the conduit when moving in the direction of small.