JP2901267B2 - Variable capacity scroll compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable displacement scroll compressor.

(Prior Art) Generally, in a variable capacity scroll compressor, a plurality of bypass holes are provided at a predetermined angular relationship at positions on a predetermined circumference of a fixed scroll member fixed in a compressor housing, In the compression process, the volume in the closed space formed by the fixed scroll member and the movable scroll member is changed by returning the fluid to the suction chamber through the bypass hole.

Such a variable displacement scroll compressor is provided with a control mechanism for opening and closing a bypass hole to change the displacement by sensing the suction pressure.

Conventionally, when controlling the opening and closing of such a plurality of bypass holes, an intermediate pressure chamber for integrating the bypass holes is provided and controlled by a single control mechanism, or a pair of control mechanisms corresponding to each of the bypass hole pairs. Is controlled by

(Problems to be Solved by the Invention) As described above, the stepwise bypass hole cannot be opened when the intermediate pressure chamber that unifies the bypass holes is provided and only the bypass flow passing therethrough is controlled. In addition, there is a problem in that the structure of the scroll compressor becomes complicated with the corresponding pair of control mechanisms.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a variable displacement scroll compressor in which a bypass hole is formed stepwise and the structure is simple.

(Means for Solving the Problems) According to the present invention, a compressor housing, a fixed scroll member fixed in the compressor housing, and a movable scroll member engaged with the fixed scroll member and performing a circular orbital motion And moving the sealed space formed by the fixed scroll member and the movable scroll member in the center direction by the circular orbital motion while reducing the volume thereof, and radially outward in the compressor housing. In a compressor for discharging a fluid taken in from a suction chamber located to a discharge chamber, the fixed scroll member has a plurality of first outwardly viewed radially inwardly of the suction chamber as viewed from a spiral body of the fixed scroll member. A bypass hole is provided,
An intermediate pressure chamber that communicates with the first bypass hole, a control hole that controls communication between the intermediate pressure chamber and the suction chamber, and an inner part of the spiral body of the fixed scroll member that is closer to the inside than the first bypass hole. A second bypass hole that is provided on one side and communicates with the suction chamber, and controls the opening of the control hole and the second bypass hole in order of the control hole and the second bypass hole according to the suction chamber pressure. And a control mechanism for closing and controlling the second bypass hole and the control hole in the order of the second bypass hole and the control hole.

(Operation) In the present invention, a plurality of bypass holes are once connected to the intermediate pressure chamber to control the communication between the intermediate pressure chamber and the suction chamber, and when the opening is sufficiently opened, the bypass hole is further provided inside as viewed in a spiral body. Since the opened and closed bypass holes are sequentially controlled by the same control mechanism, the cost can be reduced and the compression loss can be reduced to provide a structure with a wide capacity control range.

(Examples) Hereinafter, the present invention will be described with examples.

First, referring to FIG. 1, a compressor housing 1 includes a front housing 1a and a casing 1b, and a drive shaft 2 is rotatably supported on the front housing 1a.
An eccentric bush 3 is attached to one end (inner end) of the drive shaft 2. A movable scroll member 4 is mounted on the eccentric bush 3 via a bearing. In addition, the eccentric bush 3 is provided with a counter weight 5,
The front housing 1a is provided with a rotation preventing mechanism for preventing the movable scroll member 4 from rotating. The movable scroll member 4 includes a plate 41 and a spiral 42 formed on one surface of the plate 41.

A fixed scroll member 5 is fixed to the casing 1b so as to face the movable scroll member 4. The fixed scroll member 5 includes a plate body 51 and a spiral body 52 formed on one surface of the plate body 51.
The spiral body 42 and the spiral body 52 are meshed with a predetermined angular relationship.

Therefore, when the drive shaft 2 is driven, the orbiting scroll member 4 moves in a circular orbit without rotating. Thereby, the sealed space (fluid pocket) formed by the movable scroll member 4 and the fixed scroll member 5 moves toward the center while reducing its volume.

A suction chamber 6 is formed outside the movable scroll member 4 and the fixed scroll member 5, and a discharge chamber 7 is formed at the center on the right side of the fixed scroll member 5.

Here, referring also to FIG. 2 and FIG. 3, the plate 41 has a disk shape, and has a pair of bypass holes 41a and 41b. Further, a second bypass hole 41c is formed inside the first bypass holes 41a and 41b. In addition,
A discharge hole 41d communicating with the discharge chamber 7 through the discharge valve 7a is formed near the center of the plate 41, and an opening 41e is provided near the outer end of the plate 41.

The compressor housing 1 includes a bellows chamber 8 and a cylinder 9 located below the bellows chamber 8 via a partition wall 91.
Is formed, and the bellows chamber 8 communicates as shown in the figure.
It is connected to the suction chamber 6 via 81. In the bellows chamber 8, a bellows 10 whose inside is vacuumed or communicated with the atmosphere is arranged with one end (upper end) fixed, and the other end (lower end) of the bellows 10 is in contact with a ball 10a.

The partition wall 91 has through holes 91a and 91 extending vertically.
e, 91f are formed, and a valve seat 91b is provided at an upper end of the through hole 91e.
Is provided. The ball 10a is inserted into the through hole 91e.
Is inserted. A slidable push rod 91c that may also serve as an orifice is inserted into the through hole 91a. On the lower side of the push rod 91c, a passage 91d connected to the through-hole portion 91a and extending in the lateral direction is provided.
Is connected to the discharge hole 41d via the communication passage 92 and the filter 83. Further, the through-hole portion 91e is connected to the cylinder portion 9 via a communication passage 93.

A piston 11 is arranged in the cylinder section 9, and the piston 11 is urged upward by a predetermined urging force by a coil spring 12 arranged in the cylinder section 9. The pair of bypass holes 41a and 41b are connected to the intermediate pressure chamber 13 via a check valve 13a, and the intermediate pressure chamber 13 is connected to a lower portion of the cylinder section 9 via a control hole 131. Bypass hole 41
c is the intermediate pressure chamber 13 and the cylinder 9 through the bypass 13b.
Is connected to the cylinder part 9 above the connection point with the cylinder part 9. The lower end of the cylinder 9 communicates with the suction chamber 6 via the opening 41e.

When the drive shaft 2 is driven as described above, the fluid taken into the sealed space moves to the center while being compressed, and is discharged to the discharge chamber 7 through the discharge hole 41d. This discharge gas is given to the passage 91d via the communication passage 92 and the filter 83,
The push rod 91c is pushed upward. For this reason, the ball 10a is pushed upward by the push rod 91c,
The force is applied in the direction in which a contacts the valve seat 91b, and thus the force is applied in the direction in which the through-hole portion 91f is closed.
Therefore, when the pressure of the discharge gas is high, the control set suction pressure decreases.

The discharge gas is supplied to the upper portion of the cylinder 9 via the orifice and the communication passage 93.

When the compressor capacity is large with respect to the heat load, the pressure of the gas flowing into the suction chamber 6 becomes small because the high-pressure discharge gas has a large loss in the refrigerant circuit. As a result, the bellows communicating with the suction chamber 6 The pressure in the chamber 8 decreases, and the bellows 10 expands. As a result, the push rod 91c is pushed downward, and the ball 10a separates from the valve seat 91b. Therefore, the suction chamber 6
Communicates with the upper portion of the cylinder portion 9. As a result, the pressure in the upper part of the cylinder part 9 decreases, and the coil spring 12
The urging force pushes the piston portion 11 upward, and first, the control hole 131 is opened. That is, the bypass holes 41a and
41b is substantially opened, and a part of the gas in the closed space is returned to the suction chamber 6 through the bypass holes 41a and 41b, the intermediate pressure chamber 13, the control hole 131, and the cylinder section 9. Further, when the pressure in the upper part of the cylinder portion 9 decreases, the bypass passage 13b, that is, the bypass hole 41c is opened, and a part of the gas is returned to the suction chamber 6. In this way, the scroll compressor operates at a low compression capacity.

When the compressor capacity is small with respect to the heat load, the pressure of the gas flowing into the suction chamber 6 increases, and as a result, the bellows
10 shrinks, the ball 10a comes into contact with the valve seat 91b, and the through hole 91f
Is closed. Accordingly, the pressure in the upper part of the cylinder part 9 gradually increases, and the piston part 11 is pushed downward.
As a result, the bypass passage 13b and the control hole 131 are gradually closed in this order, that is, the bypass hole 41c and the bypass hole 4c.
1a and 41b are gradually closed, increasing the compression capacity.

In this way, the compression capacity is changed by controlling the opening and closing of the bypass hole by driving the piston based on the pressure of the discharge gas and the pressure of the suction gas.

(Effects of the Invention) As described above, in the present invention, a plurality of bypass holes on the outer side as viewed from the spiral body of the fixed scroll member are connected to the intermediate pressure chamber and connected together to the piston chamber. As seen from the above, only one bypass hole on the inside is required, so that it can be directly connected to the piston chamber (cylinder). Therefore, only one control mechanism is required, cost is low, compression loss is small, and the capacity control range A wide structure can be realized.

[Brief description of the drawings]

1 is a sectional view showing an embodiment of a variable displacement scroll compressor according to the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a line BB of FIG. It is sectional drawing. 1 ... compressor housing, 1a ... front housing,
1b Casing, 2 ... Drive shaft, 3 ... Eccentric bush, 4 ... Movable scroll member, 5 ... Counter weight, 5 ... Fixed scroll member, 6 ... Suction chamber, 7 ...
Discharge chamber, 8 Bellows chamber, 9 Cylinder section, 10
Bellows, 11 Piston part, 12 Coil spring, 13
... intermediate pressure chamber.

Continuation of the front page (56) References JP-A-61-291792 (JP, A) JP-A-58-128487 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F04C 18 / 02 311

Claims (1)

(57) [Claims] A fixed scroll member fixed in the compressor housing; a movable scroll member engaged with the fixed scroll member to perform a circular orbital movement; The closed space formed by the movable scroll member is moved toward the center by the circular orbital motion while reducing its volume, and the fluid taken in from the suction chamber located radially outward in the compressor housing is discharged. In the compressor that discharges into the chamber, the fixed scroll member is provided with a plurality of first bypass holes radially inward of the suction chamber and outwardly as viewed from the spiral body of the fixed scroll member. 1
An intermediate pressure chamber communicating with the bypass hole, a control hole for controlling the communication between the intermediate pressure chamber and the suction chamber, and a control hole provided inside the first bypass hole as viewed from the spiral body of the fixed scroll member. A second bypass hole communicating with the suction chamber, the control hole and the second
A control mechanism that controls the opening of the control hole and the second bypass hole in the order of the bypass holes, and controls the closing of the second bypass hole and the control hole in the order of the second bypass hole and the control hole. A variable displacement scroll compressor, comprising: