JPS6390681A - Variable capacity compressor - Google Patents

Abstract

PURPOSE:To expand the extent of capacity control by providing a first regulator for controlling the discharge capacity in response to intake pressure and a second regulator for varying discharge capacity in response to discharge pressure. CONSTITUTION:A first regulator 300 controllably opens and closes a high pressure path chamber 303 in response to intake pressure in a intake pressure chamber 301 to control discharge capacity. When pressure introduced into a high pressure path chamber 201 of a second regulator 200 exceeds a predetermined value, a valve 204 expands the area of a communicating path between an intake pressure chamber 203 and a pressure introducing path 167 and reduces pressure in a pressure chamber 151 to expand the reciprocating stroke of a piston 119. Thus, the discharge capacity can be varied with discharge pressure so that the capacity can be controlled widely from low load region to high load one.

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.

[Prior art and its problems]

BACKGROUND ART Conventionally, so-called wobble-type compressors have been known in which a swash plate is disposed at an angle with respect to a shaft, and a piston is reciprocated within a cylinder by a rocking motion based on the inclination of the swash plate. It is also known that in the one-pull type compressor, the discharge capacity of the compressor can be varied by variably controlling the inclination angle of the swash plate (see, for example, US Pat. No. 4,428,718).

In this conventional variable capacity compressor, the inclination angle of the swash plate was controlled by the suction side pressure. In other words, based on the fact that the suction side pressure varies according to the load of the refrigeration cycle, the compressor's discharge capacity is automatically adjusted by variable control of the compressor's discharge capacity according to the suction side pressure. . For example, as the cooling load increases, the pressure on the suction side increases.

Conversely, if the cooling load becomes smaller, the suction side pressure becomes lower. Based on this pressure, the pressure introduced into the pressure chamber is automatically adjusted. When the cooling load is reduced, that is, when the suction pressure is low, the control valve is driven based on the pressure fluctuation to increase the pressure supplied to the pressure chamber.

In this way, if the pressure in the pressure chamber becomes high, the angle of inclination of the swash plate becomes small, and as a result, the reciprocating stroke of the piston becomes small, and the displacement of the compressor decreases.

However, in this conventional variable displacement compressor, the pressure in the pressure chamber is controlled solely by the suction pressure, which has caused a problem in that sufficient capacity control cannot be achieved, especially at high loads.

In other words, by controlling the discharge capacity of the compressor according to the pressure on the suction side, the evaporation pressure of the evaporator is controlled to be almost constant. However, it varies depending on the cooling load. For example, during low-load operation, the amount of air taken into the evaporator is small, so frost is likely to form on the surface of the evaporator. However, when the load is high, the flow rate of air passing through the evaporator increases, so even if the evaporation pressure inside the evaporator is lowered, frost formation on the outer surface of the evaporator is suppressed. Such a state, that is, a state where the air flow passing through the evaporator is large, is a high-load operation state of the compressor, and in this state,
The pressure of the discharged refrigerant is increasing.

[Problem to be solved by the invention]

The present invention has been devised in view of the above points, and an object of the present invention is to control the pressure in the pressure chamber in accordance with the increase in the discharge pressure in a high load state where the discharge pressure increases. . That is, an object of the present invention is to enable the discharge capacity of a compressor to be variably controlled not only according to suction pressure but also according to discharge pressure.

[Configuration and operation]

In order to achieve the above object, the compressor of the present invention is provided with a pressure guiding passage for guiding a combined pressure of suction pressure and discharge pressure into the pressure chamber. A first regulator and a second regulator are provided in the middle of the pressure passage, the first regulator variably controls the pressure inside the pressure passage according to the suction pressure, and the second regulator variably controls the pressure inside the pressure passage according to the discharge pressure. It is configured to variably control the pressure inside.

That is, in the compressor of the present invention, the discharge amount of the compressor is variably controlled by the first regulator so that the suction pressure is approximately constant. In this state, the second regulator causes the discharge pressure of the compressor to exceed a predetermined value;
That is, when the compressor is in a high load state exceeding a predetermined value, the pressure inside the pressure guiding passage is controlled so that the compressor can maintain the maximum discharge capacity.

〔Example〕

An embodiment of the compressor of the present invention will be described below based on the drawings.

115 in Figure 1 is a housing made of aluminum alloy,
A plurality of cylinder spaces 117 are formed in parallel to each other inside. A pressure chamber housing 113 is disposed on the side surface of the housing 115.
13 and the housing 115, the shaft 101 is rotatably supported. That is, a bearing 158 is press-fitted into the housing 115, and this bearing supports the shaft 101.
is rotatably supported. The other end of the shaft ioi is rotationally supported by a bearing 157.

Further, a shaft seal 159 is disposed between the shaft 101 and the pressure chamber housing 113, and this shaft seal 159 allows the refrigerant and lubricating oil in the pressure chamber 151 to be released from the outside along the outer periphery of the shaft 101. leakage is prevented.

A bin guide 103 is fixed to the shaft 101, and the bin guide 103 rotates together with the shaft 101. A bin 105 is connected to the bin guide 103, and this bin allows the wobble 107 to be connected to the bin guide 103.
3. Therefore, the wobble 107 rotates together with the shaft 101. On one side of Wobble 107,
A bearing 109 is provided, and the swash plate 111 is rotatably held via this bearing.

Therefore, the rotational motion of the wobble is released by the bearing 109, and the swash plate 111
The oscillating movement of the swash plate 111, which only oscillates within the pressure chamber 151, is connected to the piston 119 via the connecting rod 131.

The piston 119 is arranged to be able to slide back and forth within the cylinder chamber 117, and a connecting recess is formed in the front surface of the piston 119, and a ball 133 at the tip of the connecting rod 131 is arranged in this recess. be done. Note that the ball 133 is held by a holding plate 135. A ball 139 is also formed at the other end of the connecting rod 131, and this ball is rotatably held by the swash plate 111 via a holding plate 137.

Here, since the wobble 107 is connected by the bin 105, the wobble can be tilted with respect to the shaft 101. Therefore, the inclination angle of the swash plate 111 is also varied according to the change in the inclination angle of the wobble. A change in the inclination angle of the swash plate 111 results in a change in the reciprocating stroke of the piston 119. Note that in order for the swash plate 111 to perform only a rocking motion and not a rotational motion, the housing 115
A support rod 153 is disposed between the pressure chamber housing 113 and the pressure chamber housing 113 . This support rod 153 is connected to the swash plate 111.
The swash plate 11 is engaged with the connecting portion 155 of the swash plate 11.
1 will only move along the support rod 153.

Note that the housing 115 and the pressure chamber housing 113
A connecting hole 163 is formed in each of the connecting holes 163, and the compressor 11 is directly fixed to an automobile engine (not shown) through the connecting hole 163.

A side plate 114 is disposed at one end of the housing 115, and a side housing 116 is further disposed outside the side plate. Inside this side housing 116 is a suction chamber 141 and a discharge chamber 1.
43 is formed. The suction chamber 141 is connected to the cylinder chamber 1 through a suction hole 145 formed in the side plate 114.
It is connected to 17. A suction valve is provided on the cylinder chamber 117 side of this suction hole 145.

The discharge chamber 143 communicates with the cylinder chamber 117 via a discharge hole 147 formed in the side plate 114.

A discharge valve 1 is provided on the discharge chamber 143 side of the discharge hole 147.
49 are arranged.

The side housing 116 also includes a second regulator 3.
00 and a second regulator 200 are provided.

A vacuum bellows 302 is disposed inside the second regulator, and the outside of the vacuum bellows is a suction pressure chamber 301, into which the pressure inside the suction chamber 141 is introduced.

A spring 320 is disposed inside the vacuum bellows 302, and a connecting rod 3 is attached to the tip of the vacuum bellows 302.
21 is connected, and at the tip of this connecting rod 321,
A valve 305 is provided. The pulp 305 opens and closes between the high pressure passage chamber 303 and the pressure guiding passage 169. The high pressure passage chamber 303 is connected to the passage 304, the high pressure passage chamber 201 of the second regulator. and communicates with the discharge chamber 143 via a passage 205.

The second regulator has a diaphragm 202 inside, and one side of the diaphragm 202 receives the discharge pressure in the high pressure passage chamber 201, and the other side serves as a constant pressure chamber 220, which receives atmospheric pressure. This displacement of diaphragm 202 is transmitted to valve 204 via connecting rod 221.

This valve 204 is connected to the suction pressure chamber 203 and the pressure guiding passage 169.
This controls the opening/closing and opening area between the opening and opening area.

The suction pressure chamber 203 communicates with the suction chamber 141 via a pressure passage (not shown) in the side housing 116.

Note that the above-mentioned pressure guiding passage 169 is connected to the side plate 114.
The pressure passage 169 communicates with the pressure chamber 151 via a pressure passage 167 of the housing 115 and a pressure passage 165 formed in the shaft.

Therefore, the pressure within the pressure guiding passage is guided to the pressure chamber 151.

The discharge chamber 143 communicates with the condenser 501 of the refrigeration cycle via a discharge passage. In addition, the capacitor 501
are receiver 505, expansion valve 502 and evaporator 5
03 and forms a refrigeration cycle together with the compressor 11. Cooled air flows through the evaporator 503 from a blower 504, and the air cooled by the evaporator is guided into the vehicle interior as cold air. Next, the operation of the compressor having the above configuration will be explained.

When the electromagnetic clutch 161 is connected, the rotational driving force of a vehicle engine (not shown) is transmitted to the shaft 101 via the electromagnetic clutch 161 .

As the shaft rotates, the wobble 107 performs a rotational oscillating motion, and the oblique vill performs a oscillating motion. The rocking motion of the swash plate 111 is transmitted to the piston 119 via the connecting rod 131, and the piston 119 is transmitted to the cylinder 117.
reciprocate within.

As the piston 119 reciprocates, the suction valve is pushed open during the suction stroke of the piston, and the low-pressure refrigerant in the suction chamber is sucked into the cylinder chamber 117 through the suction hole 145. Also, in the compression stroke of the piston 119, the cylinder chamber 117
When the refrigerant inside is compressed and reaches a predetermined pressure or higher, the refrigerant pushes open the discharge valve 149 through the discharge hole 147 and flows into the discharge chamber 143.
is discharged. The high-pressure refrigerant discharged into the discharge chamber 143 is then led to the condenser 501, where it becomes a high-temperature, high-pressure liquid refrigerant. Thereafter, it undergoes adiabatic expansion through the expansion valve 502, becoming a low-temperature, low-pressure atomized state. Thereafter, the air is evaporated in the evaporator 503, and at that time, the air to be cooled is cooled by the heat of vaporization. The low-temperature, low-pressure gaseous refrigerant evaporated in the evaporator 503 is sucked into the compressor 11 again.

The discharge capacity of this compressor is varied by changing the inclination angle of the swash plate 111. Further, the inclination angle of the swash plate 111 changes depending on the pressure within the pressure chamber 151.

That is, as the pressure within the pressure chamber 151 increases, the pressure applied to the back surface of the piston 119 also increases, and as a result, the piston 119 does not retreat much from the top dead center. In this way, if the pressure inside the pressure chamber 151 becomes high, the swash plate 11
1 becomes smaller, and the reciprocating stroke of the piston 119 also becomes smaller.

The inside of the pressure chamber 151 is controlled by the pressure guided from the pressure guiding passage 165. The pressure guiding passage 165 is connected to the high pressure passage chamber 303
It is controlled by mixing the high pressure from the suction pressure chamber 203 and the low pressure from the suction pressure chamber 203. Here, the diaphragm 202 of the second regulator has a high pressure side pressure of a predetermined value, for example, 13ksr/
Since the valve 204 is not displaced unless the pressure exceeds c11, the pressure in the pressure guiding passage 165 is mainly controlled by the second regulator 300 in medium and low operating conditions.

The second regulator controls opening and closing of the high pressure passage chamber 303 according to the suction pressure in the suction pressure chamber 301. When the load on the compressor becomes low, the suction pressure also decreases accordingly.As a result, the pressure inside the suction pressure chamber 301 decreases and the vacuum bellows 302 expands.
2 is transmitted to the valve 305 via the connecting rod 302,
As a result, the communication area between the high pressure passage chamber 303 and the pressure guiding passage 169 becomes large. As a result, the high pressure within the discharge chamber 143 flows toward the pressure guiding passages 167 and 165, and the pressure within the pressure chamber 151 increases. As a result, the angle of inclination of the swash plate 111 becomes smaller, and the reciprocating stroke of the piston 119 also becomes smaller. This reduces the discharge capacity of the compressor, and as a result, the suction pressure increases.

That is, the first regulator 300 allows the discharge capacity of the compressor to be variably controlled while always controlling the suction pressure to be substantially constant. This state is shown by solid line A in FIG.

This means that in medium and low load conditions, the suction side pressure is controlled to be substantially constant, and as a result, the evaporation pressure of the evaporator is also maintained at a substantially constant value. In this way, by maintaining the evaporation pressure of the evaporator at a constant value,
Frost formation on the outer surface of the evaporator 503 due to a decrease in suction pressure is prevented.

Although the suction pressure is kept almost constant by the regulator 300 as described above, the discharge pressure varies greatly depending on the load, as shown in FIG. That is, as the load decreases, the discharge pressure also decreases. In such a state, if the discharge capacity of the compressor decreases, the discharge pressure further decreases. Therefore, as shown in FIG. 21, the discharge pressure increases (varies) in response to changes in load. In FIG. Note that the solid line B in FIG. The air temperature will also rise.The broken line B in FIG. 2 and the broken line A in FIG.

That is, the broken lines B and A in this state indicate the control response in the conventional compressor.

In the compressor of this example, since the second regulator 200 is provided, when the high pressure is lower than the predetermined pressure, the second regulator 200
Apart from the control of the regulator, a pressure signal from the second regulator is also led to the pressure guiding passage 167,165.

That is, if the high pressure introduced into the high pressure passage chamber 201 of the second regulator exceeds a predetermined value, the diaphragm 202
is displaced, and based on this displacement, the pulp 204 moves into the suction pressure chamber 2.
The communication passage area between 03 and the pressure guiding passage 167 is increased.

As a result, the pressure in the pressure chamber 151 is reduced to the pressure guiding passage 165.1.
67 and escapes to the suction pressure chamber 203 side, thereby reducing the pressure inside the pressure chamber 151. Due to this pressure drop in the pressure chamber 151, the reciprocating stroke of the piston 119 becomes thicker. In other words, in this state, the reciprocating stroke of the piston regulated by the first regulator generates an even larger reciprocating stroke. This state is shown by the solid line in Fig. 3. When the discharge pressure reaches the predetermined pressure (13 kg/c+fl) in this way, the discharge capacity of the compressor is further increased.As a result, the suction pressure is The pressure will be lower than the predetermined pressure determined by the refrigeration cycle 300.As the suction pressure decreases, the evaporation pressure of the evaporator also decreases.However, in such a state, the high load state of the refrigeration cycle Therefore, since a large amount of cooling air flows into the evaporator 503, even if the evaporation pressure decreases, as shown by the dotted line in Fig. 3,
The temperature of the air blown from the evaporator is maintained at a predetermined temperature or higher.

Therefore, even if the evaporation pressure is lowered, frost formation on the outer surface of the evaporator 503 is prevented.

[Effects of the Invention] As explained above, the compressor of the present invention includes, in addition to the first regulator that controls the discharge capacity according to the suction pressure, the second regulator that varies the discharge capacity of the compressor according to the discharge pressure. This allows for optimal control of compressor capacity over a wide range of applications, from low load ranges to high load ranges.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the compressor of the present invention, and Fig. 2 shows the discharge pressure of the compressor, which is variably controlled to keep the suction pressure constant, and the evaporative lake blowout of the refrigeration cycle in which the compressor is used. Shows the relationship with air temperature. FIG. 3 is an explanatory diagram showing the relationship between the high pressure and the low pressure of the compressor shown in FIG. 1, and the temperature of the air blown from the evaporator. 11...Compressor, 101...Shaft, 107...
- Wobble, 111... Swash plate, 113... Pressure chamber housing, 115... Housing, 116... Side housing, 117... Cylinder, 119... Piston, 141... Suction chamber, 143...Discharge chamber, 1
65,167°169...Pressure passage, 200...Second regirator, Issue 300...Second regirator. 'Kuni

Claims (1)

[Claims] a housing forming a cylinder chamber therein; a piston slidably disposed within the cylinder chamber; a shaft rotatably supported by the housing; and a swash plate having a variable inclination angle with respect to the shaft. A connecting rod connecting the swash plate and the piston, a pressure chamber formed in the housing and housing the swash plate and the connecting rod, communicating with the cylinder chamber through a suction hole to guide fluid toward the cylinder chamber. a suction chamber, a discharge chamber that communicates with the cylinder chamber through a discharge hole and from which fluid is discharged from the cylinder chamber, a pressure guiding passage that guides the pressure in the suction chamber and the discharge chamber to the pressure chamber, and this pressure guiding passage. a first regulator disposed midway to control the fluid pressure guided to the pressure guiding passage in accordance with a pressure related to the suction chamber pressure; and a first regulator disposed midway in the pressure guiding passage to control the fluid pressure guided to the pressure guiding passage in accordance with a pressure related to the discharge chamber pressure. a second regulator that controls the pressure introduced into the pressure guiding passage according to the pressure, and the first regulator increases the pressure introduced into the pressure guiding passage as the pressure related to the suction pressure decreases. The variable displacement compressor is characterized in that the second regulator is controlled to reduce the pressure guided to the pressure guiding passage when the pressure related to the pressure in the discharge chamber becomes equal to or higher than a predetermined pressure. .