JPS6282290A - Variable capacity type compressor - Google Patents

Abstract

PURPOSE:To maintain compressor capacity at a constant level, by introducing the cooling medium pressure on the suction hole's downstream side into a pressure chamber on one side of a spool valve and the cooling medium pressure on the suction hole's upstream side into a pressure chamber on the other side of said spool valve, and opening or closing a bypass hole through controlling the spool valve based on the pressure difference. CONSTITUTION:Since the cooling medium pressure on the downstream side of a suction hole 204 is introduced into a pressure chamber 304 on one side of a spool valve 302 and the pressure on the upstream side of a suction hole 204 is introduced into a pressure chamber 305, a pressure drop produced in the cooling medium flowing through the suction hole 204 is applied between front and rear sides of the spool valve 302. Therefore, when a compressor is in a low revolving speed position, the pressure difference is not so large and the spool valve 302 is kept closing bypass holes 300, 301 by the energizing force of a spring 307. However, as the amount of the cooling medium increases resuting from high speed rotation, the pressure difference generated between the front and the rear sides of the suction hole 204 becomes large, resulting in a continuous displacement of the spool valve 302. Consequently, as number of revolution of the compressor becomes larger, the discharge amount increases or decreases, and retention of compressor capacity and power reduction are allowed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a variable capacity compressor, and is effective for use as a refrigerant compressor in, for example, an automobile air conditioner.

[Problems to be solved by conventional technology and invention]

Conventionally, various refrigerant compressors for automobile air conditioners have been proposed that are equipped with a bypass hole and a spool valve for opening and closing the bypass hole. For example, in the one described in Japanese Patent Application Laid-Open No. 58-128487, the spool valve is displaced in accordance with the cooling load. However, this method has the problem that the spool valve cannot be displaced with good response when the compressor suddenly accelerates, and the engine load required to drive the compressor cannot be reduced. In addition, other technologies have been proposed that open the bypass hole when the compressor suddenly accelerates, but in that case, the spool valve is driven based on the sensor that detects the sudden acceleration of the compressor and the electrical signal from that sensor. This has the disadvantage that the configuration of the actuator, etc., is complicated and the cost is high.

[Means for solving problems]

The present invention has been made in view of the above points, and an object of the present invention is to provide a compressor with a simple configuration and to reliably reduce the capacity of the compressor when the compressor suddenly accelerates.

Therefore, in the present invention, a pressure difference generated by a throttle provided on the suction side of the compressor is introduced before and after the spool valve, and the spool valve is moved based on the pressure difference.

[Effect]

When the compressor rotates at high speed, a large amount of fluid is sucked into the pressure chamber of the compressor, so that the fluid flow rate on the suction side increases.

Therefore, the throttle part provided on the suction side (e.g. suction hole)
The differential pressure that occurs before and after increases. Since this pressure difference is supplied before and after the spool valve, the spool valve will fluctuate when the compressor rotates at high speed. Thereby, the spool valve opens the bypass hole and the capacity of the compressor is reduced.

[Effects of the Invention] Since the discharge capacity can be reduced when the compressor rotates at high speed, the power required to drive the compressor can be reduced. Particularly at high rotation speeds when the capacity of the compressor decreases, the power is often excessive to begin with, so even if the capacity of the compressor is reduced, the capacity of the compressor as a whole is maintained in a sufficient state.

〔Example〕

FIGS. 1 and 2 show an embodiment of the present invention, in which 10
0 is a shaft which receives power from an automobile engine through an electromagnetic clutch (not shown) and rotates. 101 is
A rotor rotates integrally with a shaft, and the rotor 101 and shaft 100 are rotatably held by a bearing 102.

Reference numeral 103 denotes a cylindrical housing disposed on the outer peripheral side of the rotor, 104 a housing side plate disposed on the front side of the housing, and 105 a housing side plate disposed on the rear side of the housing. A seal is provided between the housing 103 and the housing side plates 104 and 105 by an O-ring 106. 107 is a front housing, and a gasket 10 made of asbestos is provided on the front side of the housing side plate 104.
It is fixed via 8. 109 is housing side plate 1
05 is fixed to the discharge chamber housing via a gasket 110 also made of asbestos. The aforementioned front housing 107, housing side plate 104, housing 103, housing side plate 105, and discharge chamber housing 109 are connected and fixed by fixing bolts 111. 113 is a discharge chamber cover disposed outside the housing 103.

The front housing 107 includes a shaft seal 112.
is arranged, thereby preventing the fluid inside the compressor from flowing out along the shirt 1-100.

A vane groove 200 is formed in the rotor 101,
A vane 201 is disposed within this vane groove so that both ends thereof are in contact with the inner surface of the housing 103. Therefore, the side surfaces of the two vanes 201, the outer surface of the rotor 101, the inner surface of the housing 103, and the housing side plates 104, 10
5 forms a compression chamber 202. This compression chamber 202
As the rotor 101 rotates, its volume increases and decreases. A suction hole 204 connecting the compression chamber 202 and the suction chamber 203 is formed in the housing side plate 104 at a position where the compression chamber 202 increases in volume. Further, in the portion of the housing 103 where the volume of the compression chamber 202 has decreased the most, a compression chamber 2
A discharge hole 206 is provided for discharging the refrigerant in 02 to the discharge chamber 205.

207 is a discharge valve that covers the discharge hole 206, and 208 is a stopper for this discharge valve 207. Discharge valve 207 and stopper 208 are fixed to housing 103 with bolts 209. The refrigerant discharged into the discharge hole 205 flows out to the discharge chamber housing side via the discharge passage 210.

300 and 301 are bypass holes provided in the housing side plate 104, which communicate the compression chamber 202 and the suction chamber 203. A spool valve 302 that controls opening and closing of the bypass holes 300 and 301 is slidably disposed within the housing side plate 104. The pressure inside the compression chamber is introduced into the first pressure chamber 304 on one side of the spool valve through the first pressure introduction hole 303. Note that the first pressure introduction hole 303
is opened near the suction hole 204 in the compression chamber.

On the other hand, the pressure inside the suction chamber 203 is introduced into the second pressure chamber 305 on the other side of the spool valve 302 through the second pressure introduction hole 306. Note that the spool valve 302 is connected to the spring 30.
7 toward the first pressure chamber 304 side.

Next, the operation of the above-mentioned constituent pressure chambers will be explained.

As the shaft 100 rotates, the refrigerant in the suction chamber 203 is introduced into the compression chamber 202 through the suction hole 204 at a position where the volume of the rotor 12 increases as the shaft 100 rotates. The refrigerant introduced into the compression chamber 202 is compressed as the volume of the compression chamber 202 decreases, and the high-pressure refrigerant flows through the discharge hole 20.
6 to the discharge chamber 205 and then to the discharge chamber housing 109 side.

The bypass holes 300 and 301 are connected to the compression chamber 202 and the suction chamber 20.
In order to communicate with
Compression starts only when the value exceeds 1. Therefore, when the bypass holes 300 and 301 are open, the discharge capacity of the compressor decreases. In particular, since the spool valve 302 is continuously displaced, the degree of opening and closing of the bypass holes 300 and 301 is continuously displaced in accordance with the displacement of the spool valve 302.
Therefore, the discharge capacity of the compressor also increases and decreases continuously. In the figure, the bypass holes 300° and 301 are far apart,
According to experiments conducted by the inventors, it has been recognized that the discharge capacity fluctuates continuously even with this configuration.

A suction hole 20 is provided in the first pressure chamber 304 on one side of the spool valve.
4.Refrigerant pressure on the downstream side is introduced.1. Conversely, the second pressure chamber 30
Since the pressure on the upstream side of the suction hole 204 is introduced into the inside of the
A pressure drop that occurs when the refrigerant flow passes through the suction hole 204 is applied before and after the spool valve 302 . Therefore, in a state where the refrigerant flow rate is relatively low, that is, at a low rotational position of the compressor, the differential pressure is not so large, and the spool valve 302 is held in a state in which the bypass holes 300 and 301 are closed by the biasing force of the spring 307. .

However, as the refrigerant flow rate increases, the pressure difference generated before and after the suction hole 204 also increases, and the spool valve 302 is continuously displaced based on the pressure difference.

That is, if the differential pressure applied before and after the spool valve 302 becomes larger than the set pressure of the spring 307, the spool valve 30
2 is displaced upward in FIG. 3 against the biasing force of the spring 307.

FIG. 4 shows this state, where the solid line A shows the characteristics of a compressor without bypass holes 300 and 301, and the broken line B shows the characteristics of the compressor with the above configuration. The bypass hole 301 begins to open from point C in the figure, and the bypass hole 301 begins to open at point D.
is completely open.

Therefore, during this time, as the refrigerant flow rate increases, that is, as the compressor rotational speed increases, the discharge capacity of the compressor increases and decreases, and the overall capacity of the compressor is kept constant. As a result, as shown in the figure, the amount of effort required to drive the compressor has been significantly reduced. This means that the load applied to the engine is reduced, especially when the vehicle accelerates rapidly, and as a result, the fuel efficiency of the vehicle engine is improved.

In addition, in the above example, the pressure difference before and after the suction hole 204 was used as a means to increase the refrigerant flow rate, but the pressure difference after the throttle phloem provided on the upstream side of the compressor can also be used in addition to the suction hole 204. is also possible. For example, the front housing 107
The differential pressure before and after the suction port 400 formed in the first. Second
It may also be guided into pressure chambers 304 and 305.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of the compressor of the present invention, and shows a cross-sectional shape taken along line I-1 in FIG. FIG. 2 is a sectional view of the compressor shown in FIG. 1 taken along line nn. Figure 3 fat,
(b) is a sectional view showing the operating state of the spool valve, and FIG. 4 is a graph showing the characteristics of the compressor shown in FIG. 1. 100... shaft, 101... rotor, 103...
...Housing, 201... Vane, 204... Suction hole. 206...Discharge hole, 300, 301...Bypass hole. 302...Spool valve. Representative Patent Attorney Takashi Okabe 1st Dimensions

Claims (2)

[Claims] (1) A shaft that rotates by receiving a driving force from the outside, a rotor that rotates integrally with the shaft, a housing that surrounds the rotor, a vane that is slidably disposed on the rotor, and the rotor and the rotor. Housing: a suction hole that supplies fluid to a pressure chamber formed by the vane, a discharge hole that discharges fluid from the pressure chamber, and a bypass that is provided in the housing and communicates the pressure chamber upstream from the suction hole. A variable displacement compressor comprising a hole and a spool valve that opens and closes the bypass hole, the spool valve moving according to a pressure difference between fluids flowing into the pressure chamber. (2) The fluid pressure downstream of the suction hole is introduced into one side of the spool valve, the fluid pressure upstream of the suction hole is introduced into the other side of the spool valve, and the spool valve is connected to the front and rear of the suction hole. Claim 1 which moves according to differential pressure
Variable capacity compressor as described in section.