JP2550612B2 - Capacity control mechanism of scroll compressor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacity control mechanism for a scroll compressor that is widely used for refrigerant compression in air conditioners and the like.

(Prior Art) Conventionally, this type of capacity control mechanism is disclosed in, for example, Japanese Patent Laid-Open No. 61-29.
As disclosed in Japanese Patent No. 1792, and as shown in FIG. 7, a pair of bypass holes (M, M) are provided in a casing (K) in which a fixed scroll (X) and a movable scroll (Y) are installed. Bypass passage (R, R) to bypass to L) side
Is integrally formed in a hollow shape, and the bypass hole (M,
Control mechanism (C) including an electromagnetic valve (E) for opening and closing a valve body (V, V) disposed opposite to M) and an operating cylinder (D)
Is incorporated in one side portion of the casing (K).

Then, by opening the solenoid valve (E), the high pressure of the discharge chamber (H) is introduced to the rear surface of the operation cylinder (D) to operate the cylinder (D), and the bypass passage (R,
By blocking the communication hole (T) between R) and the suction port (L),
The intermediate pressure fluid discharged from the bypass holes (M, M) during the compression stroke is filled in the passages (R, R) to increase the internal pressure of the passages (R, R) and close the valve body (V, V). In this way, full capacity operation is performed.

On the other hand, by closing the solenoid valve (E), the cylinder (D) is restored by the spring (N), the communication hole (T) is opened, and the passages (R, R) are communicated with the suction port (L). Partial capacity operation is performed.

(Problems to be solved by the invention) However, in the above configuration, the bypass passages (R, R) that connect the bypass holes (M, M) to the suction port (L) side
And the control mechanism (C) for the valve body (V, V) that opens and closes the bypass hole (M, M), both fixed and movable scrolls (X)
The casing (K) is provided by using the casing (K) which is internally provided with (Y) and protects the exterior by concealing the inside of the compressor.
In view of maintaining the internal airtightness and the object of processing the casing (K), which is a large-sized member for partitioning the external appearance, it is difficult to construct the entire capacity control mechanism and the processing cost increases.

An object of the present invention is to provide a scroll type compression mechanism having a simple structure and improved workability by forming a mechanism for capacity control separately from a casing and mounting the mechanism on the upper surface of a fixed scroll. The point is to provide a capacity control mechanism for the machine.

(Means for Solving Problems) Therefore, the casing (1) is provided with fixed and movable scrolls (2) and (3) in which end plates (21) and (31) are provided with spiral bodies (22) and (32), respectively. The interiors are combined in a combined manner so as to face each other, and two systems of compression chambers (A) and (B) are formed between the spiral bodies (22) and (32), and suction fluid is supplied in these compression chambers (A) and (B). In addition to the compression, the compression chambers (A) and (B) in the middle of the compression stroke are communicated with the suction side through a pair of bypass holes (6A) and (6B) respectively opened in the compression chambers (A) and (B). In a displacement control mechanism of a scroll type compressor for performing displacement control, the bypass holes (6A) (6B) are provided on the upper surface side of the end plate (21) of the fixed scroll (2).
Are formed, and seat holes (2A) (2B) having a diameter larger than the diameter of the bypass holes (6A) (6B) are formed symmetrically with respect to the center (O) of the fixed scroll (2), and the bypass holes ( 6A) (6
A pair of bypass passages (8A) and (8B) for communicating B) with the suction side respectively, and a valve hole (62A) for mounting a pair of unloader pistons (9A) and (9B) for opening and closing the seat holes (2A) and (2B). ) (62B) and an unloader valve block (60) arranged symmetrically with respect to the center (S), and this valve block (60) is provided on the upper surface of the end plate (21) of the fixed scroll (2). They were installed with their centers aligned.

(Operation) A pair of bypass passages (8A) (8B), unloader pistons (9A) (9B), and the unloader pistons (9A) (9B) are installed in an unloader valve block (60) provided separately from the casing (1). Since the valve holes (62A) (62B) are formed and the unloader valve block (60) is attached to the upper surface of the end plate (21) of the fixed scroll (2),
Each bypass passage (8A) (8B) and valve hole (62A) (62
B) can be processed for this valve block (60) to improve its workability. Further, at the time of processing, the bypass passages (8A) (8B) and the valve hole (62) are processed.
Since A) and (62B) are arranged symmetrically with respect to the center (S), processing can be performed more easily with the center (S) as a reference.

Further, the bypass holes (6A) (6B) are opened to seat holes (2A) (2B) having a diameter larger than the diameter of the bypass holes (6A) (6B), and these seat holes (2A) (2B) are provided. Is formed symmetrically with respect to the center (O) of the fixed scroll (2), and the valve block (60) is attached to the upper surface of the end plate (21) of the fixed scroll (2) with its center aligned, Since the seat holes (2A) (2B) are opened and closed by the unloader pistons (9A) (9B), the bypass holes (6A) (6B) are asymmetric with respect to the center (O) of the fixed scroll (2). Even if the seat block is opened to the above position, the displacement can be absorbed by the seat holes (2A) and (2B), the mounting direction of the valve block (60) does not need to be restricted, and the mounting error can be surely prevented. However, even if the opening position of each bypass hole (6A) (6B) changes depending on the model, the valve block (60 Since widened range that can be directly applied to heterogeneous without changing the dimensions, is the attained generic of capacity control mechanism.

Further, regarding the airtightness of each part constituting the capacity control mechanism, since the valve block (60) is arranged on the end plate (21) of the fixed scroll (2) in the casing (1),
Since it is only necessary to consider the airtightness inside the valve block (60) and the airtightness between the valve block (60) and the end plate (21), the airtightness is improved.

(Embodiment) The structure shown in Fig. 1 is a fixed type in which a spiral body (22) conforming to the involute shape is projectingly provided on an end plate (21) through a frame (10) in a closed casing (1). The scroll (2) and the movable scroll (3), which also has a scroll (32) projecting on the end plate (31) and which conforms to the involute shape, are internally mounted in combination so as to face each other, and the drive shaft of the motor (4). A movable scroll (3) is provided via an eccentric rotation part (5) provided with a counterweight (51) and a swing link (52) driven by (40) and an Oldham ring (53) constituting a rotation preventing mechanism. Is orbitally driven with respect to the fixed scroll (2), and suction fluid taken in from the suction ports (11) and (11) is formed between the spiral bodies (22) and (32) to form two compression chambers (A) (B). ), And is discharged from the discharge hole (12).

In the end plate (21) of the fixed scroll (2), as clearly shown in FIG. 3, a pair of bypass holes (6) respectively opened in the compression chambers (A) and (B) in the middle of the compression stroke.
A) (6B) and a pair of suction communication holes (7A) (7B) communicating with the suction ports (11) (11).

The bypass holes (6A) (6B) are spiral bodies (22) (32).
A pair of sliding contact points (PA) (PB) along the tangential direction of the same pass through the holes (6A) and (6B) at the same time, and two compression chambers (A) and (B) secured inside from the passing point. It is installed at a position where pressure can be balanced between them. In this case, since the center of the basic circle (22a) forming the involute of the scroll (22) is generally placed at the center (O) of the fixed scroll (2), the two bypass holes (6A) (6B) are The opening will be in an asymmetrical position with respect to the center (O). In FIG. 3, white arrows indicate the moving directions of the sliding contacts (PA) (PB) due to the rotation of the movable scroll (2).

And a pair of bypass passages (8A) and (8B) for communicating the bypass holes (6A) and (6B) with the suction communication holes (7A) and (7B), respectively, and a pair of opening and closing the bypass passages (8A) and (8B). The unloader valve block (60) including the unloader pistons (9A) and (9B) is formed, and the valve block (60) is attached to the upper surface of the end plate (21) of the fixed scroll (2).

As clearly shown in FIGS. 4 and 5, the valve block (60) has a silencer muffler (61) integrally covering the discharge hole (12) in the central portion thereof, and the piston (9) is provided on both left and right sides thereof.
A) A port cover (63) in which valve holes (62A) (62B) that freely slide inside A (9B) and the bypass passages (8A) (8B) continuous with the valve holes (62A) (62B) are arranged symmetrically with respect to the center (S) ) Is provided. The sound deadening muffler (61) includes a discharge valve (13) that is opened and closed by an increase in internal pressure in the compression chamber on the innermost side of the spiral, that is, a compression chamber communicating with the discharge hole (12), and its valve retainer (14).
A discharge chamber (16) which is internally provided with a discharge valve block (15) including and is partitioned on the upper surface side of the fixed scroll (2).
Through the communication hole (64). An external discharge pipe (17) is connected to the discharge chamber (16).

As shown in FIG. 6, the port cover (63) has an elongated hole (65) as shown in FIG. 6, and a gasket (66) formed by compressing a material such as asbestos into a thin plate is interposed. , The upper lid (67) is bolted.

A control pressure introducing pipe (68) that is selectively switched between a high pressure side and a low pressure side is connected to the center of the upper lid (67), and a valve hole (62A) is provided through a gap of the vent hole (65). The control pressure is introduced to the back pressure chambers (69A) (69B) of the pistons (9A) (9B) in (62B).

The unloader piston (9A) (9B) has a large diameter part (9
This is a so-called poppet type in which a valve seat (93) made of resin or the like is integrated with a caulking pin (94) at the tip of a valve body (90) having 1) and a small diameter portion (92). The seal ring (95) fitted around the large diameter part (91) maintains the sealing property between each back pressure chamber (69A) (69B) side and the bypass passage (8A) (8B) side,
Also, the stepped portion (96) between the large diameter portion (91) and the small diameter portion (92).
In each piston (9A) (9B) bypass hole (6A) (6B)
The coil springs (18) for urging in the opening direction are in contact with each other.

Then, as shown in FIG. 2, the unloader valve block (60) has its center (S) aligned with the center (O) of the fixed scroll (2) and is bolted to the upper surface of the end plate (21). ing.

On the other hand, the bypass hole (6
A) (6B) around, seat holes (2A) (2B) having a larger diameter than the bypass holes (6A) (6B) are provided symmetrically with respect to the center (O), and the seat holes (2A) (2B), the piston (9
Valve seat (4A) for seating each valve seat (93) of A) (9B)
(4B) so that each piston (9A) (9B) symmetrically arranged in the center (O) can open and close each bypass hole (6A) (6B) asymmetrically arranged in the same center (O). ing.

With the above configuration, when high pressure is introduced from the introduction pipe (68) into each back pressure chamber (69A) (69B), each piston (9A)
(9B) moves against the spring (18), seats its seat (93) on the valve seats (4A) (4B) to close the bypass holes (6A) (6B), and The communication from 6A) and (6B) to the suction side is cut off, compression is performed in the entire range from the suction port (11) to the discharge hole (12), and operation at full capacity is performed.

On the other hand, when each back pressure chamber (69A) (69B) is opened to the low pressure side, each piston (9A) (9B) is returned to the open side by the spring (18), and the bypass holes (6A) (6B) are drawn into the suction port. By communicating with the (11) side and bypassing the intermediate pressure fluid in the middle of the compression stroke to the suction side, low capacity partial capacity operation is performed.

In this case, the bypass passage (8
A) (8B) and pistons (9A) and (9B) for communicating or blocking the bypass passage to the suction side are arranged in the unloader valve block (60), and the valve block (60) is fixed scroll (2). Since it has a structure to be mounted on the upper surface of the end plate (21) of, the internal valve holes (62A) (62B) of each bypass passage (8A) (8B) and each piston (9A) (9B) are processed by this valve. The block (60) can be used as a target, and the processing convenience is improved compared to the case where a conventional casing is processed, and at the time of processing, only the confidentiality of each part constituting the capacity control mechanism is maintained. Therefore, the confidentiality can be improved.

Also, a valve hole (62A) that guides each piston (9A) (9B).
(62B) and the bypass passages (8A) and (8B) are symmetrically arranged with respect to the center (S) of the valve block (60), and the center (S) is matched with the center (O) of the fixed scroll (2). The bypass holes (6A) and (6B) that are to be installed asymmetrically with respect to the center (O) and are to be opened asymmetrically with respect to the bypass holes (6A) and (6B) are intermediately seated holes (2A) and (2B). Since it absorbs it, there is no need to restrict the left and right mounting directions of the valve block (60), and it is possible to reliably prevent a mounting error due to a mistake in the left and right.

Moreover, the seat holes (2A) and (2B) are bypass holes (6A).
(6B) has a large diameter to absorb the positional deviation, and the valve block (60) that constitutes the capacity control mechanism is a separate member from the casing (1). Even if the size of the scrolls (2) and (3) changes due to the change and the opening positions of the bypass holes (6A) and (6B) change, the valve block (60) can be applied to different models without changing the dimensions. Therefore, the capacity control mechanism can be generalized.

(Effect of the invention) As described above, in constructing the capacity control mechanism in the present invention, the bypass holes (6A) and (6B) are opened on the upper surface side of the end plate (21) of the fixed scroll (2), and the bypass holes are formed. (6A)
Seat holes (2A) and (2B) having a diameter larger than that of (6B) are formed symmetrically with respect to the center (O) of the fixed scroll (2), and the bypass holes (6A) and (6B) are respectively provided on the suction side. A pair of bypass passages (8A) (8B) communicating with the seat hole (2A)
(2B) open / close pair of unloader pistons (9A) (9
An unloader valve block (60), which is arranged symmetrically with respect to the center (S), with valve holes (62A) and (62B) for accommodating B) is formed separately from the casing (1), and this valve block (6
0) is attached to the upper surface of the end plate (21) of the fixed scroll (2) with its center aligned, so that the bypass passages (8A) (8B) and the valve holes (62A) (62B) are machined. This valve block (60) can be used as a target to improve its workability, and during processing, the bypass passages (8A) (8B) and the valve holes (62A) (62B) are mainly used. Since they are arranged symmetrically with respect to (S), processing can be performed more easily with the center (S) as a reference.

Further, the bypass holes (6A) (6B) are opened to seat holes (2A) (2B) having a diameter larger than the diameter of the bypass holes (6A) (6B), and these seat holes (2A) (2B) are opened. Fixed scroll (2)
Of the fixed scroll (2) is formed symmetrically with respect to the center (O) of the fixed scroll (2).
Align the centers with the upper surface of the
Since (2B) is opened and closed by the unloader pistons (9A) and (9B), even if the bypass holes (6A) and (6B) are opened asymmetrically with respect to the center (O) of the fixed scroll (2), The seat holes (2A) and (2B) can absorb the positional deviation, no restriction is required in the mounting direction of the valve block (60), and the mounting error can be reliably prevented.
Even if the opening position of each bypass hole (6A) (6B) changes depending on the model, the valve block (60) can be applied to different models without changing its dimensions, so it is a general-purpose capacity control mechanism. It can be realized.

Further, regarding the airtightness of each part constituting the capacity control mechanism, since the valve block (60) is arranged on the end plate (21) of the fixed scroll (2) in the casing (1),
Since it is only necessary to consider the airtightness inside the valve block (60) and the airtightness between the valve block (60) and the end plate (21), the airtightness can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a scroll type compressor having a capacity control mechanism of the present invention, FIG. 2 is a plan view of the II arrow, and FIG. 3 is the same.
Fig. 4 is an enlarged cross-sectional view of the main part from III-III, Fig. 4 is a vertical cross-sectional view of the main part around the unloader valve block, Fig. 5 is a bottom view of the valve block, and Fig. 6 is a gasket which is one component of the valve block. FIG. 7 is a vertical sectional view of a conventional example. (1) …… Casing (2) …… Fixed scroll (3) …… Movable scroll (6A) (6B) …… Bypass hole (8A) (8B) …… Bypass passage (9A) (9B) …… Unloader piston (21) (31) …… End plate (22) (32) …… Vortex body (A) (B) …… Compression chamber (60) …… Unloader valve block (2A) (2B) …… Seat hole (62A) (62B) …… Valve hole (O) …… Fixed scroll center (S) …… Valve block center

Claims (1)

(57) [Claims] 1. A casing (1) is provided with fixed and movable scrolls (2) and (3) in which end plates (21) and (31) are provided with scrolls (22) and (32), respectively. The two compression chambers (A) and (B) between the spiral bodies (22) and (32).
To compress the intake fluid in these compression chambers (A) and (B), and to open the compression chambers (A) and (B) in the compression stroke to the compression chambers (A) and (B), respectively. In a displacement control mechanism of a scroll compressor, which is connected to the suction side through a pair of bypass holes (6A) (6B) to control the displacement, an upper surface of an end plate (21) of the fixed scroll (2). On the side, the bypass holes (6A) (6B) are opened, and the seat holes (2A) (2B) having a diameter larger than the diameter of the bypass holes (6A) (6B) are attached to the center (O) of the fixed scroll (2). ), And a pair of bypass passages (8A) and (8B) that connect the bypass holes (6A) and (6B) to the suction side, respectively, and the seat hole (2
A) A pair of unloader pistons that open and close (2B) (9A)
Centered on the valve hole (62A) (62B) that houses (9B) (S)
An unloader valve block (60) is formed symmetrically with respect to the valve block (60), and the valve block (60) is attached to the upper surface of the end plate (21) of the fixed scroll (2) with its center aligned. Capacity control mechanism of the scroll type compressor.