JP2000177375A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the abnormal rise of discharge pressure of a working fluid by opening a first passage for connecting a discharge part to a drive chamber by a discharge displacement changing means when the discharge pressure of the working fluid is in a prescribed pressure state, and providing a diaphragm in a second passage for connecting the drive chamber to a suction part. SOLUTION: The discharge chamber 120 of a variable displacement compressor 101 having a discharge quantity variable according to the inclination of a swash plate 130 is connected to a drive chamber 110 through a heating discharge displacement changing passage 201, and a first discharge displacement changing valve 181 is interposed in the passage 201. The drive chamber 11 is connected to a suction chamber 115 through a pressure reducing passage 202, and a second discharge displacement changing valve 185 is interposed in the passage 202. When the discharge pressure of a working fluid abnormally rises in heating operation, the valve element 211 of the first discharge displacement changing valve 181 is opened by the differential pressure between the discharge pressure and the internal pressure of the drive chamber 110, while the valve element 213 of the second discharge displacement changing valve 185 is moved in throttling direction, and the inclination of a wash plate 130 is reduced to reduce the discharge capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having at least a heating circuit which operates by using a working fluid compressed by a variable displacement compressor, and more particularly to an air conditioner which rapidly increases the discharge pressure of the working fluid. The present invention relates to an air conditioner that can be suppressed.

[0002]

2. Description of the Related Art An example of this type of air conditioner is disclosed in Japanese Unexamined Patent Publication No.
No. 9630. As shown in FIG. 1, this air conditioner includes a compressor 1, a cooling circuit 51, a heating circuit 52, and a control device 83. The cooling circuit 51
The compressor 1 includes a condenser 55, a first expansion valve 57, and a heat exchanger 59 provided on a path from the discharge section D to the suction section S of the compressor 1. Is sucked into the compressor 1 via the above devices, and this cycle is repeated. The heating circuit 52 includes a bypass 5 extending from the discharge section D of the compressor 1 to the heat exchanger 59.
2a, a second expansion valve 63 provided on the bypass passage 52a, and the heat exchanger 59. The high-pressure working fluid discharged from the compressor 1
5, the refrigerant is sucked into the compressor 1 via the second expansion valve 63 and the heat exchanger 59, and this cycle is repeated. The heating circuit 52 is generally called a hot gas bypass heater. Switching between the cooling circuit 51 and the heating circuit 52 is performed by opening and closing operations of the switching valves 53a and 53b, and the opening and closing operations are controlled by the control device 83.

[0003] In the case of this type of air conditioner, when the heating circuit 52 is used, the discharge pressure of the working fluid is higher than when the cooling circuit 51 is selected. Therefore, abnormal high pressure is likely to be applied during the operation of the heating circuit 52. For example, when the rotation speed of the compressor 1 temporarily increases during the operation of the heating circuit 52, an abnormally high pressure state is likely to occur. Therefore, in the related art, a working fluid discharge passage 91 further provided with a pressure relief valve 93 is provided. The working fluid discharge passage 91 includes a heating circuit 52 and a cooling circuit 5.
The pressure relief valve 93 is opened to discharge the working fluid to the cooling circuit 51 side when the discharge pressure of the working fluid becomes abnormally high during the operation of the heating circuit 52. This prior art includes a cooling circuit 51 and a heating circuit 5.
Paying attention to the fact that 2 is selected by the switching valves 53a and 53b, when the discharge pressure becomes abnormally high during the operation of the heating circuit 52, the working fluid is discharged to the unused cooling circuit 51 side. By doing so, abnormal high pressure is not applied to the heating circuit 52.

[0004]

This conventional technique for preventing abnormal high pressure is a system in which a working fluid is discharged from an operating heating circuit 52 to an unused cooling circuit 51, and the discharge pressure during the operation of the heating circuit 52 is controlled. Can be suppressed, but the working fluid in the heating circuit 52 is discharged to the cooling circuit 51 every time the discharge pressure increases, and the heating circuit 52
It is likely that the working fluid in the interior will decrease and the heating capacity will be insufficient. Further, the conventional technology for countermeasures against abnormal high pressure causes the compressor 1 to work and discharges the working fluid that has been pressurized to a high pressure to the outside of the circuit, so that the energy efficiency is low.

Therefore, in the present invention, in order to suppress an abnormally high pressure state during the operation of the air conditioner, the working fluid in the heating circuit is discharged to the cooling circuit and the heating capacity becomes insufficient. It is an object of the present invention to solve the problem that the working fluid, which has been raised to a high pressure through work, is wastefully discharged to the outside of the heating circuit and energy efficiency deteriorates.

[0006]

Means for Solving the Problems Each of the inventions described in claims 1 to 6 is constituted as means for solving the above problems. In addition, in each invention, "squeezing" a predetermined passage includes both reducing the cross-sectional area of the passage and blocking the passage.

In the air conditioner of the first aspect, a variable displacement compressor is used as an operation source of the heating circuit. A variable displacement compressor is a compressor that can reduce the discharge capacity by increasing the pressure in a driving chamber. In this air conditioner, the discharge pressure of the working fluid is reduced by reducing the discharge capacity of the variable displacement compressor, thereby taking measures against an abnormally high discharge pressure of the working fluid. That is, a measure against abnormally high discharge pressure is achieved by utilizing the inherent characteristics of the variable displacement compressor. Specifically, when the discharge pressure of the working fluid reaches a predetermined pressure state, the discharge capacity changing unit opens the first passage connecting the discharge unit and the drive chamber to connect the discharge unit and the drive chamber. The communication state is established. Then, the compressed high-pressure working fluid is discharged from the discharge section on the high-pressure side to the drive chamber on the low-pressure side.

Further, in the present air conditioner, in conjunction with the opening of the first passage, the second passage connecting the drive chamber and the suction section is throttled. The high-pressure working fluid discharged from the discharge section into the drive chamber is retained in the drive chamber by being restricted in the second passage, so that the pressure in the drive chamber is rapidly increased. That is, as compared with the configuration in which the fixed throttle is provided in the second passage, the maximum boosting effect in the driving chamber can be obtained only by discharging a smaller amount of the working fluid from the discharge portion to the driving chamber. As a result, it is possible to obtain a limited discharge capacity reduction effect. As a result, not only does the function of reducing the amount of working fluid discharged from the discharge section into the drive chamber to minimize the deterioration of energy efficiency, but also the discharge of the working fluid from the discharge section into the drive chamber at an extremely early stage. The capacity control also works, and the responsiveness in the countermeasure against abnormally high pressure of the discharge pressure of the working fluid by the discharge capacity control is improved.

As described above, the second passage is throttled in conjunction with the opening of the first passage. As a result, the pressure in the drive chamber is increased, and the drive means reduces the discharge capacity. As a result, the discharge pressure of the working fluid is reduced. And the abnormal high pressure state of the discharge pressure of the working fluid is eliminated. In this case, the pressure in the drive chamber is quickly increased as compared with the case where the fixed throttle is provided in the second passage, so that the abnormally high discharge pressure state can be eliminated more quickly, and the overall response to the abnormally high discharge pressure countermeasures is taken. The performance is improved. After the abnormal high pressure control ends and the discharge pressure returns to normal, the first passage is closed and the second passage is opened. Then, the working fluid discharged into the drive chamber is sent to the suction section via the second passage that connects the drive chamber to the suction section, and suction, compression, and discharge are repeated again.

The technique of reducing the discharge pressure of the working fluid with good responsiveness works particularly well when the heating circuit is operated. When the heating circuit is activated, the working fluid is used at a higher pressure than when the cooling circuit is activated, so the allowable range up to the upper limit of the discharge pressure is narrowed, and even a slight increase in the discharge pressure is abnormal. This is because a high pressure state is likely to occur, and it is necessary to control the discharge pressure more strictly than when the cooling circuit is operating. According to the above configuration, the abnormally high discharge pressure state during the operation of the heating circuit can be quickly and effectively eliminated. In addition, since the working fluid of the discharge unit is discharged to the drive chamber in order to eliminate the abnormal high pressure state, some energy loss occurs, but the second passage is narrowed in conjunction with the opening of the first passage. The amount of working fluid to be sent to the drive chamber to obtain the effect of suppressing the abnormally high discharge pressure can be minimized, and the working fluid discharged into the drive chamber after the abnormally high discharge pressure has been suppressed. Is sent to the suction section and reused. Therefore, as in the related art, the problem caused by discarding the working fluid to the outside of the circuit, that is, the working fluid decreases every time an abnormally high discharge pressure is taken. Problem that the circuit operation ability is insufficient,
There is no problem that the working fluid that has been pressurized by performing the compression work is discarded out of the circuit and energy efficiency is deteriorated. In the heating circuit of the present air conditioner, it is preferable to provide a pressure reducing device such as an expansion valve between the discharge section and the heat exchanger.

[0011] In the air conditioner according to the second aspect, a cooling circuit is added to the air conditioner according to the first aspect, and a bypass circuit is provided from a discharge part of the compressor to a heat exchanger which is a component of the cooling circuit. Is configured. The heating circuit having such a configuration is generally called a hot gas bypass heater. The technique of reducing the discharge pressure of the working fluid with good responsiveness works particularly favorably at the time of operating the heating circuit when the heating circuit is configured as a hot gas bypass heater as in the air conditioner of the second aspect. Since the hot gas bypass heater is configured to bypass the cooling circuit while also using a part of the members constituting the cooling circuit, the circuit capacity is relatively small,
Therefore, the degree of increase in the discharge pressure of the working fluid tends to be sharp, and therefore, in addition to the characteristics of the heating circuit described in claim 1, quick management of the discharge pressure is more strongly required. In the heating circuit of the air conditioner, it is preferable to provide a decompression device such as an expansion valve on a bypass from the discharge section to the heat exchanger.

According to a third aspect of the present invention, the discharge capacity changing means in the air conditioner according to the first or second aspect is the first type.
And a second valve body connected to the first valve body to restrict the second passage. According to the present air conditioner, measures against the abnormally high discharge pressure of the working fluid described above are taken through the first and second valve bodies of the valve.

According to a fourth aspect of the present invention, in the air conditioner of the third aspect, the first valve body and the second valve body are connected to form a valve having an integral structure. According to the present air conditioner, measures against the abnormally high discharge pressure of the working fluid described above are taken through the valve having an integral structure, and the configuration of the air conditioner is simplified. Preferably, such a unitary valve is provided in the compressor.

According to a fifth aspect of the present invention, in the air conditioner of any one of the first to fourth aspects, the throttle of the second passage interlocked with the opening of the first passage blocks the second passage. Until you do. When the first passage is opened, the working fluid discharged from the discharge unit into the drive chamber completely stays in the drive chamber because the second passage from the drive chamber to the suction unit is blocked. Therefore, it is possible to more quickly increase the pressure in the drive chamber as compared with the case where the second passage is narrowed in the sense of reducing the cross-sectional area of the second passage. On the other hand, in the drive room of the present air conditioner, although the high-pressure working fluid is discharged from the discharge unit via the first passage, the second passage from the drive room to the suction unit is blocked.
The pressure in the drive chamber may become too high and create a high pressure condition that exceeds the sealing capability of the device. In particular, the sealing around the drive shaft of the compressor cannot withstand the high pressure in the drive chamber, which may cause problems such as leakage of working fluid. Therefore, in the present air conditioner, a third passage connecting the drive chamber and the suction unit is provided separately from the second passage. When the pressure in the driving chamber becomes a predetermined high pressure state, the pressure in the driving chamber is reduced by releasing the working fluid from the driving chamber to the suction section by connecting the third passage. This prevents a problem that the sealing ability of the device does not function due to the pressure in the drive chamber becoming too high.

In the air conditioner according to claim 6, the third passage is
The valve is opened via a valve that opens when the pressure difference between the pressure in the drive chamber and the suction pressure of the working fluid increases. By opening the third passage, the working fluid is discharged from the drive chamber to the suction section,
It is possible to prevent a problem that the sealing ability of the device does not function due to the pressure in the driving chamber becoming too high.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, an air conditioner according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG.
00 is a cooling circuit 151 and a heating circuit 1
52 and a variable displacement compressor 101 which is a driving source of both circuits
And is constituted by. Although the discharge capacity changing means as one of the components of the present invention is shown in FIG.
FIG. 2 showing the general configuration of the air conditioner 100 is not shown. The structure and operation of the discharge capacity changing means will be described later in detail. In the present embodiment, the air conditioner 100 is configured as an on-vehicle air conditioner, and the drive shaft 125 of the variable displacement compressor 101 is
70 and is driven.

The cooling circuit 151 includes the variable displacement compressor 101
The first expansion valve 157 and a condenser 155 that operates using the high-pressure working fluid compressed by the first expansion valve 157 and are disposed on a path 151 a from the discharge part D to the suction part S of the variable displacement compressor 101. , Heat exchanger 159 and accumulator 16
And 1. Heat exchanger 159 is commonly referred to as an evaporator.

The heating circuit 152 is also a variable displacement compressor 101.
The second expansion valve 163 is operated on the high-pressure and high-pressure working fluid compressed in the second step, and is disposed on a bypass 152 a that guides the working fluid discharged from the discharge part D to the heat exchanger 159.
And the heat exchanger 159 and the accumulator 161. That is, the heating circuit 152 has a structure that also serves as a part of the components of the cooling circuit 151. The heating circuit 152 having such a structure is commonly called a hot gas bypass heater.

The heat exchanger 159 is juxtaposed with the hot water heater 171. Cooling hot water from the engine 170 is circulated in the hot water heater 171 via a pipe 173.
In FIG. 2, a first on-off valve 153a and a second on-off valve 153b
Is a switching valve for selectively operating either the cooling circuit 151 or the heating circuit 152.

When the cooling circuit 151 operates, the working fluid which has been compressed by the variable capacity compressor 101 and has become high temperature and high pressure is sent to the condenser 155, where the heat of the high temperature working fluid is discarded to the outside. Liquefy. Next, the working fluid is decompressed by the first expansion valve 157 and
It is sent to 59, where it takes external heat and gasifies. The gasified working fluid is returned to the variable displacement compressor 101 via the accumulator 161 and is recirculated. When the heating circuit 152 operates, the variable displacement compressor 10
The working fluid that has been compressed at 1 and has become high temperature and high pressure is decompressed by the second expansion valve 163 and sent to the heat exchanger 159, where it releases heat to the outside. During the cycle of the heating circuit 152, the working fluid always circulates in a gaseous state through the heating circuit 152.

In the present embodiment, the heating circuit 152 is positioned as an auxiliary heating device. That is, the heat generated by the heat exchanger 159 during the operation of the heating circuit 152 is used as an auxiliary heating heat source for the hot water heater 171 described above. The heating circuit 152 is used, for example, at the time of starting the engine 170 or in a low-temperature environment such as when the outside air temperature is -20 ° C., for example, when the cooling water of the engine 170 does not have enough heat for heating.

Next, with reference to FIG. 3, the structure of the variable displacement compressor 101 for supplying high-pressure working fluid to the cooling circuit 151 and the heating circuit 152 and operating both circuits will be described.
A drive chamber 110 is formed in a housing 101 a of the variable displacement compressor 101, and a swash plate 130 is supported by a drive shaft 125 in the drive chamber 110. Swash plate 130
Is supported by the drive shaft 125, and rotates with the rotation of the drive shaft 125 while being inclined with respect to the drive shaft 125. Further, the inclination angle of the swash plate 130 with respect to the drive shaft 125 is variable. Hereinafter, approaching a state orthogonal to the drive shaft 125 is referred to as “stand up of the swash plate 130”, and approaching horizontal in the illustrated state. "The swash plate 130 sleeps."

The swash plate 130 is connected at its peripheral edge to the head of the piston 135 via a movable shoe 131. A total of six pistons 135 are arranged around the drive shaft 125 (only one piston is shown in the figure), and are inserted into the six cylinder bores 109 so as to be slidable in the left-right direction in the figure. 6 cylinder bores 1
09 is fixed by a housing 101a of the variable displacement compressor 101 in the circumferential direction. As shown, when the swash plate 130 is inclined and rotates together with the drive shaft 125,
For the piston 135 fixed in the circumferential direction,
The periphery of the swash plate 130 slides. When the peripheral edge of the swash plate 130 inclined to the piston side is located corresponding to the piston 135 (FIG. 3 shows this state), the piston 135
Is inserted deepest into the cylinder bore 109. Swash plate 1
When the peripheral edge (the peripheral edge shown in the lower part of FIG. 3) of the piston 30 that is most inclined to the opposite side of the piston is located corresponding to the piston 135 (from the state of FIG.
The piston 135 is drawn out most from the cylinder bore 109. When the drive shaft 125 makes one rotation, each piston 135 makes one reciprocation in the left-right direction in each cylinder bore 109.

The bottom of each cylinder bore 109 has a suction hole 1
18a and a discharge hole 123a are provided, and the suction valve 118 corresponds to the suction hole 118a, and the discharge valve 123 corresponds to the discharge hole 123a. Each suction hole 118
a communicates with the suction chamber 115, and each discharge hole 123 a communicates with the discharge chamber 120. Piston 1 by swash plate 130
When 35 moves to the left in the figure, the working fluid is
16 to suction chamber 115, suction hole 118a, suction valve 118
Through the cylinder bore 109. Then
When the piston 135 moves rightward in the figure by the swash plate 130, the sucked working fluid is compressed to a high pressure state, and the discharge hole 123a, the discharge valve 123, the discharge chamber 120
Is discharged from the discharge port 121 via the

The displacement of the variable displacement compressor 101 is determined by the stroke of the piston 135. The stroke amount of the piston 135 is determined by the inclination angle of the swash plate 130. The more the swash plate 130 lies, the greater the stroke amount of the piston 135, and the larger the displacement of the variable displacement compressor 101. Conversely, the swash plate 130
, The stroke amount of the piston 135 becomes smaller, and the displacement of the variable displacement compressor 101 becomes smaller.

The inclination angle of the swash plate 130 is
It is determined by the difference between the pressures acting on both sides, that is, the difference between the pressure in the drive chamber 110 and the pressure in the cylinder bore 109. In the present embodiment, this differential pressure is adjusted by increasing or decreasing the pressure in drive chamber 110. Drive room 1
When the pressure in 10 is increased, the swash plate 130 rises, the stroke amount of the piston 135 decreases, and the discharge capacity decreases.
When the discharge capacity decreases, the discharge pressure of the working fluid decreases and the suction pressure increases. When the pressure in the drive chamber 110 is reduced, the swash plate 130 lies down, the stroke amount of the piston 135 increases, and the discharge capacity increases. When the discharge capacity increases, the discharge pressure of the working fluid increases and the suction pressure decreases. In the present embodiment, when the discharge capacity is reduced, the high-pressure working fluid in the discharge chamber 120 is discharged to the drive chamber 110 to increase the pressure in the drive chamber 110. Conversely, when the capacity is to be increased, the working fluid in the discharge chamber 120 is prevented from being discharged to the drive chamber 110. The control for changing the discharge capacity in such a manner that the discharge chamber and the drive chamber are in a communication state or a non-communication state is defined as “insertion side control”.

In the present embodiment, different means are used for discharging the high-pressure working fluid from the discharge chamber 120 to the drive chamber 110 as described above, when the heating circuit is activated and when the cooling circuit is activated. First, the means at the time of operating the heating circuit will be described. In the variable displacement compressor 101, as shown in FIG. 3, the discharge chamber 120 and the drive chamber 110 are connected to a heating discharge capacity changing passage 201 and a cooling discharge capacity changing passage 301.
Each has been contacted. A first discharge capacity change valve 181 is provided in the middle of the heating discharge capacity change passage 201. The heating discharge capacity changing passage 201 corresponds to the “first passage” in the present invention. The drive chamber 110 and the suction chamber 115 are connected by a decompression passage 202. In the middle of the pressure reducing passage 202, a second discharge capacity changing valve 185 is provided. The pressure reducing passage 202 corresponds to the “second passage” in the present invention. The pressure reducing passage 202 and the second discharge displacement changing valve 185 provided on the pressure reducing passage 202 are used for changing the discharge displacement during operation of the heating circuit and the cooling circuit. Will be described later. The first mentioned above
Discharge capacity change valve 181 and second discharge capacity change valve 185
Is incorporated in the variable displacement compressor 101 as an integral structure. Such an integrated valve structure is defined as a “three-way valve”.

A detailed configuration of the heating discharge capacity changing passage 201 will be described. Heating displacement change passage 201 for heating
Are the first and second heating discharge capacity change passages 203,
205. The discharge chamber 120 is connected to the first compartment 221 in the first discharge capacity change valve 181 by the first heating discharge capacity change passage 203, so that the pressure in the first compartment 221 is discharged. Pressure Pd. Further, the drive chamber 110 is communicated with the second compartment 223 in the first discharge capacity change valve 181 by the second heating capacity change passage 205, and therefore the pressure in the second compartment 223 is increased. Is the pressure Pc in the drive chamber 110. When the first discharge capacity changing valve 181 is placed in the state shown in FIG. 3, the first valve body 211 is pressed in a direction to close both chambers by the urging force of the spring 211a, and the first heating discharge is performed. The capacity change passage 203 and the second heating discharge capacity change passage 205 are in a non-communicating state. When the pressure difference between the discharge pressure Pd in the first compartment 221 and the pressure Pc in the second compartment 223 is increased, the first valve body 211 is actuated by the spring 2 due to the pressure difference.
It is opened by overcoming the urging force of 11a. First valve element 21
The first valve opening condition is determined by appropriately adjusting the biasing force of the spring 211a. In the present embodiment, when the discharge pressure Pd of the working fluid at the time of operating the heating circuit becomes a predetermined high pressure state (pressure evaluated as an abnormally high pressure state), the first valve body 21
1 is set to be opened.

Next, the means during the operation of the cooling circuit will be described. As shown in FIG. 3, the discharge chamber 120 and the drive chamber 110 are connected by a cooling discharge capacity changing passage 301. In the middle of the cooling discharge capacity change passage 301, a cooling discharge capacity change valve 18 is provided as a third discharge capacity change valve.
Three are placed. The discharge chamber 120 is connected to the cooling discharge capacity change valve 1 by the first cooling discharge capacity change passage 301a.
83. Therefore, the pressure in the first cooling discharge capacity changing passage 301a is the discharge pressure Pd. The cooling discharge capacity changing valve 183 is further connected to the drive chamber 110 through a second cooling discharge capacity changing passage 301b. Accordingly, the pressure in the second cooling discharge capacity changing passage 301b is set to the pressure Pc in the drive chamber 110. The cooling discharge capacity change valve 183 includes a valve body 305 and a solenoid 307.
Operating member 307a operated by
The bellows 305a expands and contracts due to a change in the suction pressure Ps in the suction chamber 115 detected by the solenoid valve portion having the connecting member 307b connecting the valve member 7a and the valve body 305 and the valve body 305 via the suction pressure detection path 303. Then, the bellows 305a moves the cooling valve element 305 via the connection rod 305b connected to the valve element 305, and the first cooling discharge capacity changing passage 301
a and a valve drive unit for setting the second cooling discharge capacity changing passage 301b to a communication state or a non-communication state. By controlling the exciting force of the solenoid 307, the set valve opening pressure of the valve body 305 due to the expansion and contraction of the bellows 305a can be appropriately changed. When the heating circuit is activated, the discharge capacity is changed through opening and closing of the first valve body 211 of the first discharge capacity change valve 181.
07 is energized to change the cooling discharge capacity change valve 1
83 is always closed.

Next, the structures of the pressure reducing passage 202 and the second discharge capacity changing valve 185 will be described in detail. Decompression passage 202
Is composed of first and second decompression passages 207 and 209. The drive chamber 110 is connected to the third chamber 231 of the second discharge capacity change valve 185 by the first pressure reducing passage 207.
Therefore, the pressure in the third compartment 231 is set to the pressure Pc in the drive chamber. Further, the suction chamber 115 is communicated with the fourth compartment 233 by the second decompression passage 209, so that the pressure in the fourth compartment 233 is the suction pressure Ps.

When the second discharge capacity change valve 185 is in the state shown in FIG. 3, the heating discharge capacity change passage 2 described above is used.
01, the second valve element 213 connected to the first valve element 211 by the connection bar is biased by the spring 211a in the direction of shutting off the third and fourth compartments 231 and 231.
233 in the opening direction (upward in FIG. 3),
Therefore, the first decompression passage 207 and the second decompression passage 209 are in communication with each other. As a result, the first valve body 211
Is shut off the heating discharge capacity changing passage 201 (that is, when the discharge chamber 120 and the drive chamber 110 are in a non-communication state), the second valve body 235
Are opened (that is, the drive chamber 110 and the suction chamber 115 are in communication). During the operation of the cooling circuit, the first discharge capacity change valve 181 is basically closed as described later, and therefore, the second discharge capacity change valve 185 is basically placed in an open state. become. That is, when the cooling circuit is activated, the driving room 11
0 and the suction chamber 115 are basically in a communicating state.

When the discharge pressure Pd of the working fluid increases during the operation of the heating circuit, the second valve body 213 determines the discharge pressure Pd in the first compartment 221 and the discharge pressure Pd in the second compartment 223. When the differential pressure from the pressure Pc increases and the first valve body 211 is opened, the third compartment 231 and the fourth compartment 233 interlock with the opening operation of the first valve body. Is moved in a direction (downward in FIG. 3) in which the communication path 235 is narrowed. Here, the stop of the communication path 235 is, for example,
The biasing force of the spring 211a and the spring 213a is appropriately adjusted, or the communication path 2 of the second valve body 213 is adjusted.
By interposing a spacer on the 35 side, the second valve body 2
13 is moved to a position where the communication path 235 is not completely blocked.

Next, the operation of the present air conditioner will be described.
As described above, when the cooling circuit 151 shown in FIG. 2 is operated, the working fluid that has been compressed by the variable capacity compressor 101 and has become high temperature and high pressure is supplied to the condenser 155 and the first expansion valve 1.
The refrigerant is returned to the variable displacement compressor 101 via the heat exchanger 57, the heat exchanger 159 and the accumulator 161, and is recirculated. When the heating circuit 152 shown in FIG. 2 is operated, the working fluid that has been compressed by the variable displacement compressor 101 and has become high temperature and high pressure is supplied to the second expansion valve 163, the heat exchanger 159, and the accumulator 161 on the bypass passage 152a. Is returned to the variable capacity compressor 101 and recirculated.

First, the operation during the operation of the heating circuit 152 will be described in detail with reference to FIGS. When the discharge pressure Pd of the working fluid becomes a predetermined high pressure state during the operation of the heating circuit 152, the pressure difference between the discharge pressure Pd and the pressure Pc in the drive chamber 110 increases, and the first pressure is increased by the pressure difference. The 211 moves in the valve opening direction, and the first discharge displacement changing valve 181 is opened. Such a predetermined high pressure state of the discharge pressure Pd at the time of operating the heating circuit is caused, for example, by an increase in the drive input to the variable displacement compressor 101 due to a sudden increase in the rotation speed of the engine 170 (see FIG. 2). . By increasing the discharge pressure Pd, the heating discharge capacity changing passage 20 is increased.
1 is opened, and the first valve body 211 and the connecting bar 2 are opened.
The second valve body 213 integrally connected at 15 moves in the throttle direction, that is, the direction in which the pressure reducing passage 202 is throttled. As a result, the high-pressure working fluid in the discharge chamber 120 is discharged to the drive chamber 110 on the low-pressure side via the discharge capacity changing passage 201 for heating.
The pressure Pc in the drive chamber 110 is immediately increased because the pressure is limited to 16. Thereby, the swash plate 130
(That is, the inclination angle of the swash plate 130 decreases), the stroke amount of the piston 135 decreases, and the discharge capacity of the variable displacement compressor 101 decreases. As a result, the discharge pressure Pd of the working fluid decreases. As a result, the abnormal high pressure state of the discharge pressure Pd is eliminated. Here, the working fluid is discharged from the discharge chamber 120 on the high pressure side to the drive chamber 110 on the low pressure side, and the pressure reduction passage 202 that connects the drive chamber 110 and the suction part is throttled. In order to change (decrease) the pressure, the high-pressure working fluid required to increase the pressure Pc in the drive chamber is required to be a minimum. Therefore, in the early stage when the discharge of the working fluid from the discharge chamber 120 to the drive chamber 110 is started, the pressure in the drive chamber 110 is sufficiently increased, and the countermeasure against the abnormally high discharge pressure Pd is quickly taken. Will be

The discharge amount of the working fluid necessary for reducing the discharge capacity and the discharge pressure, that is, the driving chamber 11
The amount of working fluid to be discharged from the discharge section 120 to the drive chamber 110 in order to increase the pressure Pc in 0 is small enough because the pressure reducing passage 202 from the drive chamber 110 to the suction chamber 115 is restricted. . Of course, an extremely small amount is required as compared with a structure in which the working fluid is directly discharged from the discharge side to the suction side to reduce the pressure.

After the above-mentioned countermeasures against abnormally high pressure of the discharge pressure Pd of the working fluid, that is, after the discharge pressure Pd has escaped from a predetermined high pressure state, the discharge pressure Pd decreases. The first valve body 211 is moved in the valve closing direction, and the discharge chamber 120 and the drive chamber 110 are brought into a non-communication state.
Will not be released. Further, the second valve body 213 connected to the first valve body 211 is moved in the valve opening direction, and the drive chamber 11
0 and the suction chamber 115 are in communication with each other, and the high-pressure working fluid retained in the drive chamber is moved from the drive chamber 110 to the suction chamber 11.
5 will be released. As a result, the pressure Pc in the drive chamber 110 is reduced, the swash plate 130 moves in the sleeping direction (direction in which the inclination angle increases), the piston stroke increases, and the discharge capacity is restored.

Next, the operation when the cooling circuit 151 operates will be described. The cooling displacement change valve 183 shown in FIG.
When the suction pressure Ps of the working fluid is lower than a predetermined reference value during the operation of the cooling circuit 151, that is, when the suction pressure Ps is in a predetermined low pressure state, the cooling fluid discharge capacity changing passage 301 is opened.
And the working fluid is discharged from the discharge chamber 120 to the drive chamber 1.
10 to increase the pressure in the drive chamber 110 and reduce the discharge capacity of the variable displacement compressor 101 to control the suction pressure Ps to be maintained at a predetermined set pressure;
This prevents frost formation on the heat exchanger 159 (see FIG. 2) that occurs when the suction pressure Ps falls below the set pressure. Specifically, when the suction pressure Ps decreases, the bellows 305a of the cooling discharge capacity change valve 183 expands by the urging force of a spring 305c provided inside, and the valve body 305 is connected to the first cooling discharge capacity change passage 301a. It moves to a position where the second cooling discharge capacity changing passage 301b is in communication with the second cooling discharge capacity change passage 301b, and the pressure in the drive chamber 110 increases, and the capacity becomes a small capacity state. Further, when the solenoid 307 is excited by control means (not shown), an urging force in the direction opposite to the direction in which the bellows 305a extends can be applied to the valve body 305. Thus, the setting of the pressure at which the valve body 305 opens due to the change in the suction pressure Ps can be changed. When the heating circuit is used, the compressor is operated at the maximum discharge capacity, and the urging force of the solenoid 307 is increased so that the discharge capacity does not change due to the fluctuation of the suction pressure Ps. The cooling discharge capacity changing passage 301b of No. 2 is always kept closed.

By the way, when the heating circuit is operated, the discharge pressure change valve 183 must be kept closed because the first discharge capacity change valve 181 controls the increase and decrease of the discharge pressure. Since the increase / decrease of the discharge pressure is controlled by the cooling discharge capacity changing valve 183, the first discharge capacity changing valve 181 needs to be always closed. However, the first discharge capacity change valve 181 is configured to be opened by the differential pressure between the discharge pressure Pd of the working fluid and the pressure Pc in the drive chamber 110, and the cooling discharge capacity change valve 183 is used.
In the case where the discharge pressure Pd suddenly increases with respect to the pressure Pc in the drive chamber 110 despite the operation of the cooling circuit,
It is also possible that the first discharge capacity changing valve 181 is opened. However, the first discharge displacement changing valve 181
Is set to a pressure higher than the discharge pressure of the cooling circuit, the first discharge capacity changing valve 1 during the operation of the cooling circuit.
81 is less frequent, and even if the first discharge capacity change valve 181 is opened, the compressor moves to the smaller capacity side, so that the discharge pressure Pd is reduced as a result. 181 is immediately closed and has little effect.

In the present embodiment, the working fluid once pressurized by the variable capacity compressor 101 to discharge the pressurized working fluid to the driving chamber 110 is slightly inferior in energy efficiency. The discharge pressure is reduced rapidly, and the working fluid is supplied to the heating circuit 152.
There is no waste of energy such as being thrown out, and there is no shortage of working fluid for operating the heating circuit 152.

According to the present embodiment, in order to suppress the abnormally high pressure state during the operation of the heating circuit, the working fluid in the heating circuit is discharged to the cooling circuit, and the heating capacity is insufficient. There is no problem that the working fluid which is made to work by the machine and is pressurized to a high pressure is wastefully discharged to the outside of the heating circuit and energy efficiency is extremely deteriorated. Moreover,
Rather than discharging the working fluid from the discharge side to the suction side and reducing the discharge pressure by the direct action of the discharge, a small amount of the working fluid is discharged to the drive chamber to increase the pressure in the drive chamber. A configuration that reduces the discharge pressure by reducing the inclination angle of the swash plate, reducing the piston stroke, and reducing the discharge capacity, that is, discharging by reducing the work of the variable displacement compressor using a small amount of working fluid. The configuration for reducing the pressure is adopted, and the waste of energy imposed for suppressing the abnormally high pressure state of the discharge pressure is minimized. Further, in conjunction with the operation of discharging the working fluid from the discharge side to the drive chamber, the throttle is formed between the drive chamber and the suction chamber, so that the drive chamber can be quickly pressurized by discharging a small amount of the working fluid, and the discharge pressure can be reduced. It is possible to obtain a good response in countermeasures against abnormal high pressure.

As shown in FIG. 3, although the drive chamber 110 is in communication with the suction chamber 115 via the pressure reducing passage 202, the working fluid discharged from the discharge chamber 120 does not discharge the drive fluid during discharge pressure control. Since it is not retained in the suction chamber 110 and is not directly discharged to the suction chamber 120, the suction pressure Ps is prevented from rising due to the direct influence of the discharge of the high-pressure working fluid. The reduction effect will last for a relatively long time. In this sense, the release of the working fluid to the drive chamber 110 in the present embodiment has a meaning that the drive chamber 110 can be used substantially as a reserve tank.

In this embodiment, the first and second displacement control valves 181 and 185 are installed in the compressor as three-way valves having an integral structure that operates by differential pressure. Is possible. For example, the first valve body 2
Although 11 is configured as a differential pressure valve that opens with a differential pressure between the discharge pressure Pd and the pressure Pc in the drive chamber 110, a low pressure side parameter is appropriately selected from, for example, atmospheric pressure, vacuum pressure, suction pressure, and the like. It is possible to use the differential pressure valve used in the above. Instead of a differential pressure valve, it is also possible to use an electromagnetic valve that is opened and closed by external control. In addition, the first and second discharge capacity change valves 181 and 185 are configured separately, and the second discharge capacity change valve 185 is connected to the pressure Pc in the drive chamber and other low-pressure side parameters (for example, atmospheric pressure, vacuum pressure). , Suction pressure, etc.)
The valve may be configured to open and close with a differential pressure between the variable displacement compressor and the first and / or second discharge displacement changing valve provided outside the variable displacement compressor. The air conditioner is configured to have a cooling circuit and a heating circuit. However, since it is mainly during the operation of the heating circuit that measures against abnormally high discharge pressure are required, the cooling circuit may be omitted. is there.

(Modification) A modification of the present embodiment will be described with reference to FIG. This modification example relates to a modification example in which the drive chamber 110 and the suction chamber 115 are connected to each other by a passage other than the pressure reducing passage 202 in the variable displacement compressor 101 according to the present embodiment. A passage connecting the drive chamber 110 and the suction chamber 115 other than the decompression passage 202 includes:
FIG. 4 shows the relief passage 403.
A relief valve 409 is provided in the middle of the relief passage 403. The relief valve 409 is provided in the drive room side compartment 41.
3. The suction chamber side compartment 415, the valve body 411 that sets both chambers in communication or non-communication state, and the valve body 411 in a non-communication direction (a direction in which both chambers are shut off and a downward direction in FIG. 4). And a biasing spring 417. The condition for opening the relief valve 409 is as follows.
When the pressure in the drive chamber 110 exceeds a predetermined pressure set for the sealing withstand pressure of the device, the pressure Pc in the drive chamber 110 is increased.
The biasing force of the spring 417 is appropriately adjusted so as to be opened based on the pressure difference between the pressure and the suction pressure Ps. In the present modification, a second discharge displacement changing valve 185a different from the above embodiment is used. Here, the first valve body 2
When the first valve body 12 moves in a direction (downward in FIG. 4) to open the heating discharge capacity changing passage 201, the first valve body 21
The springs 212a and 212b are connected so that the second valve body 213a connected to
Has been adjusted. Discharge capacity change passage 2 for heating
01 is opened and the pressure reducing passage 202 is shut off, so that high-pressure working fluid flows from the discharge chamber 120 to the drive chamber 11.
And the driving chamber 110 and the suction chamber 115
Are completely disconnected from each other, and the pressure in the drive chamber 110 is increased more quickly than in the case where the pressure reducing passage 202 is restricted. Therefore, from the viewpoint of countermeasures against abnormal high pressure of the discharge pressure of the working fluid, control with further improved responsiveness can be performed as compared with the above embodiment.

By the way, in the present modified example, the pressure reducing passage 202 is shut down instead of being throttled when the abnormally high discharge pressure is dealt with, and the pressure in the drive chamber 110 is increased more quickly. A measure is needed in case the pressure Pc becomes too high in relation to the guaranteed withstand pressure of the device. In that respect, the relief passage 403 described above is used.
And the relief valve 409 plays a major role. That is, the pressure Pc in the drive chamber 110 is equal to the suction pressure P
It is configured to open when it becomes larger than s,
When the inside of the driving chamber 110 has reached a predetermined high pressure state, the relief valve 409 is opened, and as a result, the driving chamber 110 and the suction chamber 115 are in communication with each other.
, The working fluid is relieved to the suction chamber 115. As a result, an abnormally high pressure state in the drive chamber 110 is avoided, and a high pressure state in which the sealing of the apparatus cannot be endured is avoided in the drive chamber 110.

The other configuration of the variable displacement compressor 401 used in this modification is the same as the configuration in the above embodiment, and the configuration of the cooling and heating circuit to which the variable displacement compressor 401 is connected is also described. Are equivalent. Therefore, a detailed description is omitted for convenience.

The air conditioner 401 according to this modification has a cooling circuit and a heating circuit. However, since the countermeasure against the abnormally high discharge pressure is required mainly during the operation of the heating circuit, the cooling circuit is omitted. A configuration is also possible.

In each of the above-described embodiments and the modified examples, the piston 135 is disposed only on one side of the swash plate 130 in FIGS. Although the description has been made using the type, it is also possible to configure a double-headed piston type variable displacement compressor that reciprocates by connecting pistons to both sides of a swash plate, for example.

[0048]

According to the present invention, the working fluid in the heating circuit is discharged to the cooling circuit in order to suppress the abnormally high pressure state during the operation of the air conditioner, and the heating capacity becomes insufficient. This solves the problem that the working fluid was pressurized to a high pressure and the working fluid was wasted to the outside of the heating circuit, and the energy efficiency was very poor.
Further, in the present invention, when the discharge pressure is in an abnormally high pressure state, the working fluid is discharged from the discharge portion to the drive chamber, and the passage connecting the drive chamber and the suction portion in conjunction with the discharge is narrowed. Therefore, the amount of the working fluid flowing out of the driving chamber can be reduced, the pressure in the driving chamber can be quickly increased, and the time required for suppressing the abnormally high discharge pressure of the working fluid can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of a conventional air conditioner.

FIG. 2 is a sectional view schematically showing a structure of an air conditioner according to the present embodiment.

FIG. 3 is a cross-sectional view illustrating a detailed structure of a variable displacement compressor in the air conditioner according to the present embodiment.

FIG. 4 is a cross-sectional view showing a detailed structure of a variable displacement compressor in an air conditioner according to a modification of the present embodiment.

[Explanation of symbols]

 Reference Signs List 101 compressor 110 drive chamber 115 suction chamber 120 discharge chamber 125 drive shaft 130 swash plate 135 piston 181 first discharge capacity change valve 183 cooling discharge capacity change valve 185 second discharge capacity change valve 201 heating discharge capacity change passage 202 Decompression passage 301 Cooling discharge capacity change passage

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiyuki Nakane 2-1-1 Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation (72) Inventor Kazuo Murakami 2-1-1, Toyota-cho, Kariya-shi, Aichi Stock F-term (reference) in Toyota Industries Corporation 3L011 AC01

Claims (6)

[Claims] 1. A compressor having a compressor, a heating circuit, and a discharge capacity changing means, wherein the compressor has a suction part for sucking a working fluid, a discharge part for discharging a compressed working fluid, and a drive chamber. A driving means for reducing the discharge capacity when the pressure in the drive chamber is increased, a first passage connecting the discharge section to the drive chamber, and a second path connecting the drive chamber to the suction section. 2, the heating circuit has at least a heat exchanger in a path from the discharge unit to the suction unit, and the discharge capacity changing unit is configured to control the discharge pressure of the working fluid to a predetermined pressure state. The air conditioner according to claim 1, wherein the first passage is opened when it becomes, and the second passage is narrowed in conjunction with the opening of the first passage. 2. The air conditioner according to claim 1, wherein a condenser disposed on a path from the discharge section to the suction section and a heat exchanger disposed downstream of the condenser. An air conditioner, further comprising a cooling circuit, wherein the heating circuit includes a bypass from the discharge section to the heat exchanger and a heat exchanger in the cooling circuit. 3. The air conditioner according to claim 1, wherein the discharge capacity changing unit has a valve, the valve including a first valve body that opens the first passage, An air conditioner, comprising: a second valve element that narrows the second path when the first valve element opens the first path. 4. The air conditioner according to claim 3, wherein the second valve body is connected to the second passage when the first valve body opens the first passage. An air conditioner having an integrated structure in which the first valve body and the second valve body are connected so as to reduce the pressure. 5. The air conditioner according to claim 1, wherein a third passage connecting the drive chamber and the suction section is formed, and the first passage is connected to the first passage. The restriction of the second passage in conjunction with the opening of the passage is the second passage.
Until the pressure in the drive chamber reaches a predetermined high pressure state.
An air conditioner, characterized in that a passage is opened. 6. The air conditioner according to claim 5, wherein the third passage is provided with a valve that opens when a pressure difference between a pressure in the drive chamber and a suction pressure of the working fluid increases. An air conditioner characterized by being opened.