JPH02223690A - Volume varying mechanism for scroll type compressor - Google Patents

Abstract

PURPOSE:To stably achieve a proper variable effect throughout the whole region of a rotation speed by a method wherein a suction throttle mechanism, a pressure reducing mechanism, and a compression starting delay mechanism are provided, and are controlled by means of a control valve mechanism. CONSTITUTION:A throttle spool 16 is energized in a direction in which the pass section area of an introduction passage 1a, i.e. a direction in which the volume of a control pressure chamber S1 is reduced, through the force of a press spring 17. Opening and closing spools 18a and 18b are opened and closed through control of the feed of a refrigerant gas pressure to control pressure chambers S2 and S3 on the reverse side to press springs 19a and 19b. The feed of a refrigerant gas pressure to the control pressure chambers S2 and S3 is controlled by a control valve mechanism 21. This constitution enables achievement of a proper variable effect throughout the whole region of a rotation speed.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a variable capacity mechanism in a scroll compressor used as a vehicle air conditioner or the like. [Prior Art] In the scroll type compressor disclosed in Japanese Patent Application Laid-Open No. 61-2917.92, the volume of the closed space that moves to the starting end side of the spiral section provided upright on the base end wall of the fixed scroll is reduced. The intermediate region and the suction pressure region are connected by a bypass passage from the back side of the base end wall of the fixed scroll, and a bypass opening/closing mechanism that can open and close the bypass passage using refrigerant gas pressure is interposed on the bypass passage. This bypass opening/closing mechanism includes a piston that opens and closes the bypass passage, and an electromagnetic valve that controls the introduction of discharged refrigerant gas into a cylinder chamber that accommodates the piston. When the magnetic valve is open, the discharged refrigerant gas flows into the cylinder chamber,
The piston is biased toward the bypass passage closing position against the action of the spring. When the solenoid valve is in the closed state, the discharge refrigerant gas is prevented from flowing into the cylinder chamber, and the piston is biased to the bypass passage open position by the action of the spring. Therefore, when the solenoid valve is closed, the refrigerant gas in the process of being compressed is returned to the suction pressure region, and the discharge capacity can be reduced. [Problem B to be solved by the invention] However, when the rotational speed of the compressor is in a high speed region, the closed space whose volume is decreasing momentarily passes through the entrance of the bypass passage, so the It is difficult for refrigerant gas to flow back into the suction pressure region through the bypass passage compared to when the speed is rotating. Therefore, in order to increase the variable effect in the high speed region, for example, by increasing the inlet of the bypass passage, it is possible to increase the flow rate in the low speed region. If the recirculation amount of refrigerant gas becomes too large at There was a problem in that the cooling capacity in the area was left over and the variable effect became small. Furthermore, in the scroll compressor disclosed in Japanese Patent Publication No. 63-32993, a plurality of bypass passages are provided in the bottom plate of the fixed scroll, and gas is bypassed from the suction side before the start of compression and during compression. , these bypass passages alone cannot be used in high-speed rotation ranges or in areas where the cooling load is small.
When there is excess cooling capacity and the suction pressure drops, resulting in a high compression ratio or when the vehicle gets too cold, the Magneto Clasochi, which turns off the switch depending on the cooling load or the temperature inside the vehicle, turns on and off, causing unpleasant air leaks and There was a problem in that abnormal noise was generated and transmitted into the passenger compartment. An object of the present invention is to provide a variable capacity mechanism for a scroll compressor that can appropriately control the capacity of the compressor according to the cooling load even in a high speed rotation range or when the cooling load is small. [Means for Solving the Problems 1] In order to achieve the above-mentioned object, the present invention includes a suction passage whose passage cross-sectional area can be changed using refrigerant gas pressure on the introduction passage for introducing refrigerant gas into the compressor. With an aperture mechanism,
a bypass passage that passes through the base wall of the fixed scroll and connects the suction pressure region with the region where the volume is decreasing after the start of compression of the closed space that moves to the start end side of the spiral section provided upright on the base end wall of both scrolls; At the same time, a pressure reduction mechanism is provided on the bypass passage that can open and close the bypass passage using refrigerant gas pressure, and a fixed scroll is used to separate the volume decreasing region before the start of compression of the sealed space and the suction pressure region. A bypass passage is provided that penetrates and connects the base end wall, and a compression start delay mechanism that can open and close the bypass passage using refrigerant gas pressure is interposed on the bypass passage, and a compression start delay mechanism that can open and close the bypass passage using refrigerant gas pressure is installed. Alternatively, a method is adopted in which each of the mechanisms described above is controlled by operating a control valve according to the rotation speed of the compressor. [Function] By adopting the above means, in the pressure reduction mechanism, the higher the rotation speed, the smaller the variable effect becomes, but in the suction throttling mechanism, the higher the rotation speed, the greater the resistance to passage of refrigerant gas, and the variable effect becomes larger. Moreover, the compression delay mechanism provides an effective variable effect before the compression starts. Therefore, by linking the opening/closing control of the pressure reduction mechanism, which has a large variable effect in the low speed range, and the suction throttle control of the suction throttle mechanism, which has a large variable effect in the high speed range, both mechanisms can achieve their respective variable effects. mutually compensate for the variable effect in the rotational speed range where it is difficult to achieve, and together with the variable effect before the start of compression of the compression start delay mechanism, achieve an appropriate variable effect in the entire range from the low speed range to the high speed range. be able to. [Example 1] An example embodying the present invention will be described below with reference to FIGS. 1 and 2. As shown in FIG. 1, a front housing 1 and a rear housing 2 are joined and fixed with an annular fixed substrate 3 in between, and a large diameter portion 4a of a rotating shaft 4 housed in the front housing 1 has a An eccentric shaft 5 is provided to protrude into the rear housing 2, and a balance weight 6 and a bush 7 are rotatably supported on the eccentric shaft 5. A movable scroll 8 is rotatably supported on the bush 7, and a fixed scroll 9 is housed and fixed in the rear housing 2 so as to face and join the movable scroll 8. 8a. A closed space P is formed by the spiral portion 9a and the spiral portions 8b and 9b. The fixed ring 10 fixed on the surface of the fixed substrate 3 facing the movable scroll 8 has a plurality of circular revolution position regulating holes 10a transparent therethrough at equally spaced positions. The movable ring 11 fixed to the back side of 8a includes
A similar revolution position regulating hole 11a is transparently provided corresponding to the revolution position regulating hole 10a. Each revolution position regulation hole 10a, l
la has disc-shaped shoes 12A and 12B with a smaller diameter than this.
are inserted, and a ball 13 is interposed between the opposing shoes 12A and 128. The shoes 12A, 12B and the ball 13 are press-fitted between the fixed base plate 3 and the movable scroll 8 due to the compression reaction, and are apparently integrated. Shoes 12A and 12B are revolution position regulating holes 10a. The shoe 12A has a circular movable area within the lla. The movable diameter of 12B is set to match the revolution radius of the eccentric shaft 5. Therefore, as shown by the two-dot chain line in FIG. 2, all the shoes 12A, 12B are sandwiched between the revolution position regulating holes 10a, lla in the same direction by the revolution of the eccentric shaft 5, and the revolution position regulating holes 10a, lla The movable scroll 8 revolves around the periphery of the movable scroll 8 without rotating. An introduction passage 1a for introducing refrigerant gas is provided on the peripheral wall of the front housing 1, and the refrigerant gas introduced into the front housing 1 from the introduction passage 1a passes through a passage on the fixed base plate 3 to both scrolls 8. , 9 into the closed space P between them. As the movable scroll 8 revolves, the volume of the closed space P decreases as it moves toward the starting end of the spiral portion 8b. As a result, the refrigerant gas in the closed space P is compressed, and the refrigerant gas compressed between both scrolls 8 and 9 is passed from the base end wall 9a of the fixed scroll 9 through the discharge port 9e, which is releasably closed by the discharge valve 14. The liquid is discharged into the discharge chamber 15 on the back side. A throttle spool 16 is disposed on the introduction passage la so as to be slidable in the orthogonal direction, and a small diameter portion 16a is formed in the center of the throttle spool 16 with the same length as the diameter of the introduction passage 1a. A pressure spring 17 is interposed in a chamber closed by one large diameter portion of the throttle spool 16, and the accommodation chamber of the other large diameter portion serves as a control pressure chamber S1. The throttle spool 16 is urged by a pressure spring 17 in a direction that reduces the passage cross-sectional area of the introduction passage ia, that is, in a direction that causes a reduction in the volume of the control pressure chamber S1. Between the fixed scroll 9 and the rear housing 2, there is an intermediate pressure chamber 2a connected to the suction chamber of the rear housing 2;
A pair of holes 9c and 9d are formed in the base end wall 9a of the fixed scroll 9 so as to be adjacent to each other with the wall of the spiral portion 9b placed therebetween. As shown in FIG. 2, one passage 9c has both scrolls 8,
9 is provided at a position after starting compression, and the other port 9
d is provided at a position before both scrolls 8 and 9 start compression. As shown in FIG. 1, one of the ports 9c is connected to the intermediate pressure chamber 2a via the bypass path L1, and the other port 9d is connected to the intermediate pressure chamber 2b via the bypass path L2. Opening/closing spools 18a and 18b are located on the bypass passages Ll and L2, in which the passages L1 and L2 connect the closed space P and the intermediate pressure chambers 'la and 'lb, respectively, L2. The bypass passage Li is opened and closed by pressing springs 19a and 19b.
. It is biased in the direction of opening L2. The opening/closing spools 18a, 18b are provided with pressing springs 19a919.
Control pressure chamber s2 on the opposite side to b. It is opened and closed by controlling the supply of refrigerant gas pressure to the control pressure chamber s2.s3. The supply of refrigerant gas pressure to s3 is controlled by a control valve mechanism 21. In the same control valve mechanism 21, a ball valve 23 in a valve housing 22 is connected to a diaphragm 2 via a rod 23a.
A suction chamber in the rear housing 2 is connected to an input boat 22a on the peripheral surface of the pulp housing 22, and a discharge chamber 15 is connected to an input boat 22b on the lower surface. One output port 22c on the peripheral surface of the pulp housing 22 has a control pressure chamber S.
1 is connected to the other output capo) 22d, and a control pressure chamber s2. s3 is connected. An introduction passage 1a is connected to a pressure chamber 226 that is closed off in the pulp housing 22 by the diaphragm 24, and the suction refrigerant gas pressure before the throttle spool 16 is introduced into the pressure chamber 22e. When the suction pressure introduced into the pressure chamber 226 is high, that is, when the cooling load is high, the diaphragm 24 is pushed up, and the ball valve 23 closes one input boat 22a and closes the other input boat 2.
Open 2b. As a result, the discharged refrigerant gas in the discharge chamber 15 is transferred to each control pressure chamber s1. s2. s3, and the control pressure chambers Si, s2. The pressure of s3 increases to a level equivalent to the discharge pressure. When the suction pressure is low, or when the cooling load is low, the diaphragm 24 is pushed down, and the ball valve 23 closes the input port 22b side and opens the input port 1-22a side. As a result, the suction chambers in the rear housing 2 are connected to each control pressure chamber sl. s2. s3, and the control pressure chamber s1. s2. The pressure of s3 decreases to the equivalent of the suction pressure. When the control pressure chamber Sl reaches a high pressure equivalent to the discharge pressure, the throttle spool 16 moves against the pressure spring 17, and only the small diameter portion 16a of the throttle spool 16 is located on the introduction passage la. In this state, the passage cross-sectional area in the introduction passage 1a becomes maximum. Moreover, when the control pressure chamber S2 reaches a high pressure equivalent to the discharge pressure,
The opening/closing spool 18a moves against the pressure spring 19a,
Bypass passage L1 is closed. As a result, the refrigerant gas in the closed space P, which is in the process of decreasing in volume after compression, will not flow back to the suction pressure region via the bypass passage Ll.
When the control pressure chamber S3 reaches a high pressure equivalent to the discharge pressure, the bypass passage L2 is similarly closed, and the refrigerant gas in the closed space P before compression does not flow back from the bypass passage L2 to the suction pressure region. , the capacity of the compressor remains the same,
Sufficient cooling capacity is demonstrated. When the control pressure chamber S1 reaches a low pressure equivalent to the suction pressure, the large diameter portion of the throttle spool 16 protrudes onto the introduction passage la, and the passage cross-sectional area in the introduction passage 1a is narrowed. When the control pressure chamber S2 reaches a low pressure equivalent to the suction pressure, the opening/closing spool 18a moves in the opening direction by the action of the pressure spring 19a, and the bypass passage L1 is opened. Refrigerant gas in space P flows through bypass passage L
1 to the suction pressure region. When the control pressure chamber S3 becomes low pressure equivalent to the suction pressure, the bypass passage L is opened in the same way.
2 is opened, and the refrigerant gas in the closed space P before the start of compression is recirculated from the bypass passage L2 to the suction pressure region. Therefore, the capacity of the compressor becomes sufficiently small, and the cooling capacity can be significantly reduced. That is, the aperture spool 16, the pressure spring 17, and the control royal S
1; a pressure reduction mechanism including an opening/closing spool 18a, a pressure spring 19a, and a control pressure chamber S2;
Opening/closing spool 18b, pressure spring 19b, and control pressure chamber S3
The compression start delay mechanism is controlled in conjunction with the supply of either discharge pressure or suction pressure by the control valve mechanism 21. Therefore, the pressure reduction mechanism that operates after the start of compression has a variable effect that becomes smaller as the rotation speed increases;
The higher the rotation speed, the greater the resistance to passage of refrigerant gas and the greater the variable effect.Using this mechanism in combination with the suction throttle mechanism compensates each other for the variable effect in the rotation speed region where each variable effect is difficult to achieve, and also makes it possible to start compression. By combining a compression start delay mechanism that delays the start of compression by previously releasing refrigerant gas from the bypass passage L2, the cooling capacity can be effectively controlled in the entire rotation range. Bypass passage L1. The opening/closing of L2 and the throttle adjustment of the introduction passage 1a are performed by switching between introducing the discharge pressure and introducing the suction pressure in accordance with the detection of the suction pressure before the throttle which reflects the cooling load. In other words, the suction pressure before throttling, which reflects the cooling load, is not directly used as a driving force for variable action, but is used for switching control of the control valve mechanism 21, and the supply pressure is switched between the discharge pressure and the suction pressure. One control valve mechanism 21 that performs control
The configuration that incorporates this makes it possible to control both the pressure reduction mechanism and the suction throttle mechanism reliably and with high precision, and it is easy to optimize the compensation effect of the variable effect in the entire range from low speed range to high speed range. In this way, the capacity reduction rate of the compressor can be improved in the entire range from low speed to high speed, and stable capacity variation can be achieved. Therefore, even in a high speed range or in an area where the cooling load is small, the suction pressure does not drop to a high compression ratio, and unpleasant squeaks and abnormal noises do not occur due to turning on and off of the magnetic clutch. The present invention is not limited to the above-mentioned embodiments, and can be configured as follows, for example, without departing from the spirit of the invention. Either the suction pressure or the discharge pressure is controlled in the control pressure chambers sl, s2. s
It can be supplied to 3.

【Effect of the invention】

As described in detail above, the present invention is equipped with a suction throttle mechanism, a pressure reduction mechanism, and a compression start delay mechanism, and these are controlled by one control valve mechanism, so that an appropriate variable effect can be achieved over the entire rotational speed range. It has excellent effects that can be achieved stably.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are diagrams showing embodiments of the present invention,
Figure 1 is a side sectional view of the scroll compressor, Figure 2 is the
It is a sectional view taken along the line AA in the figure. The movable scroll 8, the fixed scroll 9, the base end wall 9a, the throttle spool 16 and the control pressure chamber S that constitute the suction throttle mechanism.
1. Opening/closing spool 18a and 1 constituting the pressure reduction mechanism
llli pressure chamber S2, opening/closing spool 18b constituting the compression start delay mechanism, control pressure chamber S3, control valve mechanism 21, sealed space P

Claims (1)

[Claims] 1. In a scroll-type compressor that forms a closed space between a fixed scroll and a movable scroll that faces the fixed scroll and revolves non-rotatably, the capacity of which decreases based on the revolution of the movable scroll, refrigerant gas is introduced into the compressor. A suction throttling mechanism whose passage cross-sectional area can be changed using the refrigerant gas pressure is interposed on the introduction passage for the purpose of this, creating a sealed space that transitions to the starting end of the spiral part erected on the base end walls of both scrolls. A bypass passage is provided to connect the volume decreasing region after the start of compression and the suction pressure region through the base end wall of the fixed scroll, and a bypass passage is provided on the bypass passage that can be opened and closed using refrigerant gas pressure. A bypass passage is provided which passes through the base end wall of the fixed scroll and connects the volume reduction region of the sealed space before the start of compression and the suction pressure region through a pressure reduction mechanism, and a refrigerant is disposed on the bypass passage. A compression start delay mechanism that can open and close the bypass passage using gas pressure is interposed, and each of the mechanisms is controlled by actuation of a control valve according to the suction refrigerant gas pressure before throttling, the cooling load, or the compressor rotation speed. Variable capacity mechanism in scroll compressor.