JPH10148189A - Variable displacement scroll type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the manufacturing cost rise of a variable displacement scroll type compressor, while sufficiently ensuring closeness of an operation chamber. SOLUTION: Valve elements 13a and 13b for opening/closing bypass ports 11a and 11b are slidably arranged in the axial direction of a shaft 3, and also crowning parts 13c and 13d, protruded on an operation chamber V side with a curved surface drawn, are formed on the operation chamber V side out of the sliding direction end part of the valve elements 13a and 13b. When the bypass ports 11a and 11b are closed, the crowning parts 13c and 13d are contacted constantly with the tip part side 4c of the tooth part 4b of a movable scroll 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable capacity scroll compressor (hereinafter, abbreviated as "compressor"), and is applied to a compressor for compressing a compressible fluid such as a compressor of an air conditioner. It is effective.

[0002]

2. Description of the Related Art As a variable capacity mechanism of a general compressor,
For example, in the invention described in Japanese Patent Publication No. 1-299994,
There has been proposed a fixed scroll end plate provided with a bypass port communicating with a suction port at a portion corresponding to a compression process, and opening and closing the bypass port to change a suction volume (capacity).

[0003]

Since the working chamber of the compressor is formed by the teeth and end plates of the movable scroll and the teeth and end plates of the fixed scroll, the working chamber is sealed. In order to maintain the property, it is necessary to keep the gap between the tip of both teeth and the corresponding end plate within a predetermined value.

To cope with this need, in the invention described in the above publication, there is provided a means for making the end plane of the working chamber side of the valve body for opening and closing the bypass port coincide with the plane of the end plate of the fixed scroll. Has been taken. However, according to the means described in the above publication, the dimension L _{1 of the} valve 13 is
Since the third dimension L ₁ is necessary to manage the dimension L ₂ of the end plate portion 8a side of the fixed scroll corresponding (see FIG. 5),
This increases the manufacturing cost of the valve element and the fixed scroll, and in turn increases the manufacturing cost of the compressor.

[0005] Further, even if the two dimensions are within the manufacturing tolerance, depending on the combination of the manufacturing tolerance, as shown in FIG. 5, the end plane 131 of the valve body 13 falls below the plane 81 of the end plate 8a. May form a concave shape. In such a case, since the fluid in the working chamber V leaks through the recess, the hermeticity of the working chamber V cannot be sufficiently ensured.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to prevent a rise in the manufacturing cost of a variable displacement scroll compressor while ensuring sufficient sealing of the working chamber.

[0007]

The present invention uses the following technical means to achieve the above object. In the invention according to claim 1 or 2, the bypass port (11a, 1
1b) can be slid in the axial direction of the shaft (3), and the valve element (13a, 13b) can open and close the valve element (1b).
On the working chamber (V) side of the sliding direction ends of 3a, 13b), crowning portions (13c, 13d) projecting with a curved surface toward the working chamber (V) are formed. When closing the bypass ports (11a, 11b), the crowning portions (13c, 13d) are always in contact with the tip side (4c) of the tooth portion (4b) of the movable scroll (4). As a result, the tip side (4c) of the tooth portion (4b) of the orbiting scroll (4) and the crowning portions (13c, 13d) are formed.
Is always in contact when the bypass ports (11a, 11b) are closed, so that the working chamber (V) can be sufficiently sealed.

[0008] Also, crowning portions (13c, 13d)
Is positively brought into contact with the tip end side (4c) of the tooth part (4b) to ensure the hermeticity of the working chamber (V), so that the sliding dimensions of the valve bodies (13a, 13b) The dimension on the end plate portion (8a) side of the fixed scroll (8) corresponding to the dimension in the sliding direction is referred to as "the problem to be solved by the invention".
It is not necessary to manage strictly as in the means described in the section.
Therefore, since the manufacturing cost of the valve bodies (13a, 13b) and the fixed scroll (8) does not increase, it is possible to prevent the manufacturing cost of the variable displacement scroll compressor from increasing.

According to a second aspect of the present invention, a high hardness layer having a high hardness is formed on the surface of the crowning portions (13c, 13d). Thereby, uneven wear of the crowning portions (13c, 13d) can be prevented, so that the crowning portions (13c, 13d) can be prevented.
The occurrence of poor sealing of the working chamber (V) due to uneven wear in 3d) can be prevented. Therefore, it is possible to prevent the durability of the variable displacement scroll compressor from decreasing.

[0010] The reference numerals in parentheses of the above means indicate the correspondence with the specific means described in the embodiment described later.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; (Embodiment) FIG. 1 is a sectional view showing a structure of a variable displacement scroll compressor (hereinafter, abbreviated as a compressor) according to the present embodiment, wherein 1 is a front housing (housing). A shaft 3 is rotatably supported by a bearing 2 pressed into a housing 1. The shaft 3 is configured to rotate by obtaining a driving force from a driving source such as an engine via an electromagnetic clutch (not shown) connected to one end. The shaft 3 may be directly driven by an electric motor or the like without using an electromagnetic clutch.

An eccentric portion 3a is provided at a position eccentric from the center of rotation of the shaft 3 by a predetermined amount. The eccentric portion 3a is provided on a boss portion 4c of the movable scroll 4 to be described later.
It is inserted via a bearing 5 described later. Reference numeral 4 denotes a movable school made of an aluminum alloy driven by the shaft 3. The end plate portion 4a of the movable scroll 4 has spiral tooth portions projecting from the end plate portion 4a in the axial direction of the shaft 3. 4b are formed. A boss 4c is formed substantially at the center of the end plate 4b of the movable scroll 4, and a bearing 5 is press-fitted into the boss 4c. Incidentally, this bearing 5 is a shell-type (type having no inner ring) needle roller bearing (needle bearing) composed of an outer ring and a rolling element arranged along the inner wall surface of the outer ring.
It is.

The orbiting scroll 4 is provided with an anti-rotation mechanism (not shown) for preventing the orbiting school 4 from rotating around the bearing 5, and is movable by the anti-rotation mechanism and the bearing 5. The scroll 4 revolves around the shaft 3 without rotating, using the amount of eccentricity of the eccentric portion 3a as the orbital radius as the shaft 3 rotates. Reference numeral 6 denotes a balance weight for canceling the centrifugal force of the movable scroll 4. The position of the center of gravity of the balance weight 6 is opposite to the position of the center of gravity of the movable scroll 4 across the shaft 3 in order to cancel the centrifugal force of the movable scroll 4. It is located in.

Reference numeral 7 denotes a lip seal which closes a gap between the shaft 3 and the front housing 1 and closes a refrigerant (and a lubricating oil mixed with the refrigerant) in the compressor from leaking out of the compressor. It is fixed in the front housing 1 by a clip (not shown). Reference numeral 8 denotes a fixed scroll made of an aluminum alloy fixed to the front housing 1 by bolts (not shown). The end plate 8a of the fixed scroll 8 has the end plate 8a.
From the movable scroll 4
A spiral tooth portion 8b meshing with the tooth portion 4b is formed. A plurality of working chambers V (see FIGS. 3 and 4) for sucking and compressing the refrigerant are formed by the tooth portions 4b and 8b and the end plate portions 4a and 8a of the scrolls 4 and 8, respectively. The hermeticity is maintained by a resin-made chip seal (not shown) attached to the tips of the teeth 4b and 4b.

A discharge port 9 for discharging the compressed refrigerant from the working chamber V is formed substantially at the center of the end plate portion 8a of the fixed scroll 8, and the discharge port 9 is located on the end plate portion 8a side. A discharge valve 9a for preventing the refrigerant from flowing back into the working chamber V and a valve stopper 9b for restricting the maximum opening of the discharge valve 9a are fixed to the end plate 8a by bolts (not shown). I have.

A rear housing 10 is attached to the fixed scroll 8 by bolts (not shown) at the end plate 8a of the fixed scroll 8, and the rear housing 10 and the end plate 8a allow the discharge port 9 to be formed. A discharge chamber Vd for smoothing the pressure pulsation of the refrigerant discharged from the nozzle is formed. The refrigerant smoothed in the discharge chamber Vd is:
The air is discharged from a discharge port (not shown) from the compressor to a condenser (not shown) of the air conditioner. Further, the refrigerant flowing out of the evaporator (not shown) of the air conditioner is sucked from a suction port (not shown) formed in the front housing 1 and a gap between the bearing 5 and the end plate portion 4 a of the movable scroll 4. , And is sucked into the working chamber V from the suction chamber formed at the spiral end of the tooth portion 4b (see FIGS. 3 and 4).

As shown in FIGS. 3 and 4, the end plate portion 8a of the fixed scroll 8 corresponds to a compression step in which the volume of the working chamber V is reduced. Are formed, and the bypass ports 11a and 11b are connected to communication passages 12 formed in the end plate portion 8a as shown in FIG.
The working chamber V communicates with the working chamber V side in the suction process in which the volume of the working chamber V increases through the a and 12b, that is, the suction port side.

The bypass ports 11a and 11b are provided with aluminum valves 13a and 13b for opening and closing the bypass ports 11a and 11b, respectively, so as to be slidable in the axial direction of the shaft 3. Body 13a, 13
On the working chamber V side among the ends in the sliding direction of b, crowning portions 13c and 13d which have been subjected to a crowning process and drawn to the working chamber V side with a curved surface are formed.

In addition, at least the surface of the crowning portions 13c and 13d of the valve bodies 13a and 13b is subjected to abrasion resistance such as nickel plating or hard anodizing to form a high hardness layer having a higher hardness than other portions. Surface treatment. By the way, 14a and 14b are cylinder parts on which the valve bodies 13a and 13b slide, and the back chambers 15a and 15b formed by the cylinder parts 14a and 14b and the valve bodies 13a and 13b
Are communicated with the discharge chamber Vd by the communication passages 16a, 16b, 17, and 18 formed at the center.

Incidentally, the communication passage 18 also serves as a fixed throttle, and reduces the pressure of the refrigerant discharged from the discharge chamber Vd to a predetermined pressure and guides the refrigerant to the back chambers 15a and 15b. In addition, back room 1
5a and 15b communicate with the suction port side through a solenoid valve 19 which is open when not energized.
During 0% operation (maximum capacity operation), the solenoid valve 19 is closed, and during variable capacity (small capacity) operation, the solenoid valve 19 is opened.

The reference numerals 20a and 20b denote valve bodies 13a and 1b.
3b on the back chambers 15a, 15b side (bypass port 11a,
11b is a coil spring that applies an elastic force to the opening direction (side where 11b opens). Next, the operation and characteristics of the compressor according to the present embodiment will be described. 1. Variable capacity (small capacity) operation (see FIG. 2) In the variable capacity operation state, the solenoid valve 19 is opened. This allows
Since the back chambers 15a and 15b communicate with the suction port side, the back chamber 1
The pressure in 5a, 15b decreases, and the coil springs 20a, 2b
The valve bodies 13a, 13b move to the rear housing 10 side by the elastic force of 0b, and the bypass ports 11a, 11b
Is opened.

Therefore, as shown in FIGS. 3 and 4, the refrigerant suction state is maintained until the working chamber V stops communicating with the bypass ports 11a and 11b. For this reason, the suction capacity of the compressor in this operating state is the volume of the working chamber V when the working chamber V stops communicating with the bypass ports 11a and 11b. Then, the suction capacity of the compressor in this operating state becomes smaller when the volume of the working chamber V becomes largest (expanded), that is, becomes smaller than the state at the end of the suction step. Become.

2. During maximum capacity operation (see FIG. 1) In the maximum capacity operation state, the solenoid valve 19 is closed. Thereby, the refrigerant pressure of a predetermined pressure is guided to the back chambers 15a and 15b, and overcomes the elastic force of the coil springs 20a and 20b, and the valve bodies 13a and 13b are connected to the bypass ports 11a and 11b.
While closing b, the crowning portions 13c and 13d are pressed so as to come into contact with the distal end side of the tooth portion 4b of the movable school 4 (the distal end of the tooth portion 4b and the tip seal) 4c.

At this time, the contact point between the tip end side 4c of the tooth portion 4b and the crowning portions 13c, 13d is displaced along the curved surfaces of the crowning portions 13c, 13d as the movable scroll 4 revolves. Since the pressure of the refrigerant (gas) acts on 15a and 15b and the crowning portions 13c and 13d are formed, the valve bodies 13a and 13b are brought into contact with each other in accordance with the displacement of the contact portion. Slide while maintaining.

Therefore, the tip side 4c of the tooth portion 4b and the crowning portions 13c, 13d are always in contact with each other during the maximum capacity operation, that is, when the bypass ports 11a, 11b are closed. The hermeticity of the working chamber V can be sufficiently ensured. Also, crowning part 1
Since the hermeticity of the working chamber V is secured by positively contacting the tip portions 4c of the tooth portions 4b with the 3c and 13d, the sliding direction dimensions of the valve bodies 13a and 13b and the sliding direction dimensions It is not necessary to strictly manage the size of the fixed scroll 8 on the end plate portion 8a side corresponding to the above, as in the means described in the section "Problems to be Solved by the Invention". Therefore, since the manufacturing costs of the valve bodies 13a and 13b and the fixed scroll 8 do not increase, it is possible to prevent the manufacturing cost of the compressor from increasing.

The tooth portions 4b of the valve bodies 13a and 13b
Parts 13c, 13 that come into contact with the tip side 4c of the
Since d has been subjected to a wear-resistant surface treatment to form a high-hardness layer, uneven wear of the crowning portions 13c and 13d can be prevented. Therefore, the working chamber V caused by uneven wear of the crowning portions 13c and 13d, etc.
Of the compressor can be prevented, so that the durability of the compressor can be prevented from lowering.

When the discharge pressure of the compressor (the pressure in the back chambers 15a, 15b) rises above a predetermined pressure during the maximum capacity operation, the electromagnetic pressure is adjusted so that the pressure in the back chambers 15a, 15b becomes the predetermined pressure. The valve 19 may be opened. This is back room 15
When the internal pressure of the valve bodies 13a, 13b rises, the valve bodies 13a, 13b
The pressing force of the (crowning portions 13c, 13d) pressing the tip side 4c of the tooth portion 4b becomes excessively large, and the tooth portion 4b
This is because of the damages.

In the above-described embodiment, the two bypass ports 11a and 11b are connected to the suction port through the communication passage 12a.
b may be independently connected to the suction port side. In the above-described embodiment, the two valve bodies 13a and 13b are simultaneously opened and closed. However, the present invention is applicable to both valve bodies 13a and 13b.
Can be independently applied to open / close control to perform a capacity (intermediate capacity) operation between the maximum capacity operation and the variable capacity (small capacity) operation. In this case, at least the crowning portion of the valve body of the closed bypass port always comes into contact with the tooth portion 4b of the movable scroll 4.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of a variable displacement scroll compressor (at the time of maximum displacement operation).

FIG. 2 is an axial sectional view of a variable displacement scroll compressor (at the time of variable displacement operation).

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a cross-sectional view taken along the line AA of FIG. 1 showing a state where the phase is shifted by 180 ° from FIG. 3;

FIG. 5 is an explanatory diagram illustrating a problem to be solved by the invention.

[Explanation of symbols]

1: Front housing (housing), 2: Bearing, 3
... shaft, 4 ... movable scroll, 5 ... bearing, 6 ... balance weight, 7 ... lip seal, 8 ... fixed scroll, 9 ... discharge port, 10 ... rear housing, 11a, 11
b: bypass port, 12a, 12b: communication passage, 13
a, 13b ... valve body, 13c, 13d ... crowning part,
14a, 14b ... cylinder part, 15a, 15b ... back chamber,
16a, 16b, 17, 18 ... communication passage, 19 ... solenoid valve.
20a, 20b ... coil springs.

Claims (2)

[Claims] 1. A housing (1, 10), a shaft (3) rotatably supported in the housing (1, 10), and a fixed scroll (8) fixed to the housing (1, 10). A spiral tooth portion (8b) formed on the end plate portion (8a) of the fixed scroll (8) and projecting from the end plate portion (8a) in the axial direction of the shaft (3); A movable scroll (4) driven by (3); and an end plate (4a) of the movable scroll (4). The end of the movable scroll (4) protrudes in the axial direction of the shaft (3). Teeth (8b) of the fixed scroll (8)
A spiral-shaped tooth (4b) meshing with the scroll, a working chamber (V) formed by the two scrolls (4, 8) and sucking and compressing a fluid, and an end plate (8a) of the fixed scroll (8). The working chamber (V) is provided at a portion corresponding to a compression step in which the volume of the working chamber (V) is reduced.
A bypass port (11a, 11b, which communicates with the working chamber (V) side during a suction process in which the volume of the working chamber (V) is increased;
11b), a valve element (13a, 13b) disposed slidably in the axial direction of the shaft (3) and opening and closing the bypass port (11a, 11b); and a valve element (13a, 13b). And a crowning portion (13c, 13d) formed on the working chamber (V) side of the sliding direction end, and protruding with a curved surface toward the working chamber (V) side. ) Always closes the bypass port (11a, 11b) at the distal end side (4) of the tooth portion (4b) of the movable scroll (4).
c) a scroll compressor of a variable displacement type, wherein the scroll compressor is in contact with c). 2. A high-hardness layer having a higher hardness than other portions is formed on the surface of the crowning portions (13c, 13d) of the valve bodies (13a, 13b). 2. The variable displacement scroll compressor according to 1.