JP3411377B2 - Automotive air conditioner with clutchless compressor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner having a clutchless compressor to which engine driving force is constantly transmitted.

[0002]

2. Description of the Related Art As is well known, a general automobile air conditioner has a built-in evaporator and an intake unit that selectively takes in vehicle interior air or vehicle interior air by means of a fan driven by a motor. A cooler unit that cools air is connected to a heater unit that is provided with a heater core having a detour and that distributes air from the cooler unit to a predetermined position in the vehicle compartment after the air has a predetermined temperature.

As shown in FIG. 5, a cooling cycle 50 used in this automobile air conditioner has, as its constituent elements, a compressor 51 driven by an in-vehicle engine.
A condenser 52 that heat-exchanges the gaseous refrigerant that has been compressed by the compressor 51 and has a high temperature and high pressure with the outside air to form a high-pressure liquid refrigerant; and a moisture and dust in the refrigerant that temporarily stores the liquid refrigerant. And a liquid tank 53 for removing the gas refrigerant and the liquid refrigerant, and an evaporator 55.
Expansion valve 54 that adiabatically expands the liquid refrigerant into a low-pressure mist-like refrigerant while controlling the amount of the refrigerant so that a predetermined superheat is obtained at the outlet, and evaporates the low-pressure mist-like refrigerant into the vehicle interior. And an evaporator 55 that cools the blown air.

The compressor 51 transmits the driving force of the engine (not shown) via a belt wound around the pulley 56, and the transmission of the driving force of the engine is turned on between the shaft of the compressor 51 and the pulley 56. , A magnetic clutch 57 is provided to turn off. That is, when the compressor 51 needs to be operated, the electromagnetic coil of the magnet clutch 57 is energized to attract the clutch plate connected to the shaft to the pulley 56, and
Transmits the rotational movement of to the shaft. On the other hand, the compressor 5
When the operation of No. 1 is unnecessary, the energization of the electromagnetic coil is stopped and the clutch plate is separated from the pulley 56.
It is designed to rotate only in the air.

However, the magnetic clutch 57
Since it is composed of an electromagnetic coil and a clutch plate made of an iron plate because it requires a certain degree of rigidity, it causes an increase in the weight of the entire compressor, and the structure is complicated, so the assemblability is poor, In addition, the cost of the compressor increased.

Therefore, in recent years, various types of compressors called clutchless compressors having a structure in which a magnet clutch is not used based on a known variable displacement swash plate type compressor have been proposed (for example, Japanese Patent Laid-Open No. 3-37378). (See the official gazette). As shown in FIG. 6, the variable capacity swash plate compressor 60 changes the reciprocating stroke of the piston 5 in the cylinder according to the suction pressure Ps of the compressor 60 by the control valve Cv, and changes the discharge amount of the compressor 60. It was done.

For example, when the heat load is low and a large amount of refrigerant is unnecessary, the stroke of the piston 5 is reduced. When the heat load is low, the pressure of the refrigerant that has finished heat exchange in the evaporator 55 and returns to the compressor 60 is also low, so the pressure Ps of the suction chamber 1 is applied to the surroundings of the bellows 2.
Extends upward, closing the first valve opening 3 and widening the second valve opening 4. A part of the high-pressure refrigerant (discharge pressure Pd) that is compressed by the piston 5 and discharged from the discharge port 6 against the discharge valve 7 into the discharge chamber 34 passes through the discharge side pressure chamber 8 as shown by the arrow and is discharged to the second side. From the valve port 4, the first communication passage R1 (passage 9
It is introduced into the crank chamber 11 through a, a passage 9b, a central hole 10 and the like). As a result, the internal pressure of the crank chamber 11 (hereinafter, crank chamber pressure Pc) increases. Since the socket plate 16 and the drive swash plate 17 are supported by the pin 22 on the lug 21 provided on the shaft 18, they are displaced from the center. Therefore, the inclination of the socket plate 16 and the drive swash plate 17 from the position orthogonal to the drive shaft 18 is reduced by the action of the moment of the difference in the force acting between the cylinder side of each piston 5 and the crank chamber 11 side,
The reciprocating stroke of the piston 5 becomes smaller. As a result, the refrigerant flow rate is suppressed by reducing the refrigerant compression amount, and an appropriate refrigerant amount corresponding to a low heat load is provided.

On the other hand, when the heat load is large and a large amount of refrigerant is required, the stroke of the piston 5 is increased. When the heat load is high, the suction pressure Ps of the refrigerant that returns to the compressor 60 after the heat exchange in the evaporator 55 is also increased, so that it flows from the suction chamber 1 through the communication hole 12 into the bellows chamber 13 of the control valve Cv. The bellows 2 contracts due to the gas pressure to open the first valve opening 3 and opens the second valve opening 4
Close. The refrigerant in the crank chamber 11 is the second communication passage R.
2 (collectively referred to as the passage 14 and the cylinder passage 15) flows to the suction chamber 1 side. As a result, the crank chamber pressure Pc decreases and becomes almost equal to the suction pressure Ps, and due to the action of the moment of the difference in the forces acting on the cylinder side of each piston 5 and the crank chamber 11 side, from the position orthogonal to the drive shaft 18. The inclination of the socket plate 16 and the drive swash plate 17 increases, and the reciprocating stroke of the piston 5 increases. If compression is performed in this state, the amount of discharged refrigerant increases, and the refrigerant flow rate becomes appropriate according to a high heat load.

[0009]

In such a variable capacity swash plate compressor 60, structurally, the inclination angles of the socket plate 16 and the drive swash plate 17 are set to zero (a state of standing upright with respect to the drive shaft 18). Compression capacity to zero. However, if the inclination angle of the drive swash plate 17 remains zero, the back pressure of the piston 5 cannot be obtained when the compressor 60 is started. Therefore, in order to obtain a predetermined discharge amount even at the time of start-up, the minimum inclination angle is designed, the return spring 39 including a coil spring is used, or both are used to minimize the discharge amount. The inclination angle is obtained so that the discharged refrigerant amount does not become zero.

Thus, the variable capacity swash plate compressor 6
In a 0-based clutchless compressor, the inclination angle of the drive swash plate 17 and the like cannot be completely zero. Therefore, in the cooling cycle 50 to which this type of clutchless compressor is applied, the engine is driven. In such a case, even if the heat load on the evaporator 55 is small, the evaporator 55 will work a little, so there is a problem that the evaporator 55 freezes.

In order to solve such a problem, the clutchless compressor disclosed in the above publication is provided with a passage opening / closing device formed of an electromagnetic valve that closes a passage leading to the suction port of the compressor, and connects the suction chamber and the crank chamber. There is a thin tube. The cross-sectional area of the flow path of the thin tube is set in a predetermined range so that a fluid resistance is generated, and the refrigerant in the crank chamber is designed to be reduced in pressure and guided to the suction chamber. Then, when the operation of the automobile air conditioner is stopped, the passage opening / closing device closes the passage leading to the intake port, and the refrigerant in the crank chamber is reduced in pressure through a thin tube to be guided into the intake chamber. It operates so as to secure the refrigerant flow path to the chamber (corresponding to the flow path indicated by the first communication passage R1 in FIG. 6). As a result, the inclination angle of the drive swash plate 17 and the like is forcibly minimized, and the lubricating oil is circulated while the refrigerant is circulated inside the compressor.

[0012]

However , depending on the operating conditions of the vehicle air conditioner or the operation of the occupant, the operation of the vehicle air conditioner may be stopped under the condition that the drive swash plate 17 or the like is inclined at the maximum inclination angle. There is also. When the passage opening / closing device is actuated to block the passage leading to the suction port even though the compressor is performing a great work, as in such a case, the operating conditions of the compressor change abruptly. It is also one of the factors that reduce the durability of the compressor due to damage.

Since the clutchless compressor is always driven by the engine, when the automobile air conditioner is not in operation, in order to improve fuel economy,
It is necessary to keep the required torque of the compressor at a small value. In order to reduce the required torque in the variable displacement swash plate compressor, it is necessary to keep the drive swash plate 17 and the like at the minimum tilt angle.

Further, the lubricating oil circulates in the cooling cycle together with the refrigerant discharged from the compressor, but if the passage leading to the inlet is blocked, the lubricating oil will not return to the compressor and the durability of the compressor will be deteriorated. There is a risk of

[0016] The present invention has been made to solve the problems associated with the prior art, a motor vehicle air conditioner having a clutchless compressor which is based on a variable capacity swash plate type compressor, a variable capacity swash Board type
A clutchless compressor consisting of a presser
While keeping the required torque at a small value, the evaporator
A first object of the present invention is to provide a vehicle air conditioner capable of achieving antifreeze .

[0017]

A second object of the present invention is to provide a vehicle air conditioner capable of preventing the evaporator from freezing while enhancing the durability of the clutchless compressor.

[0019]

SUMMARY OF THE INVENTION To achieve the first object, the present invention according to claim 1 is a clutchless compressor in which the driving force of a vehicle-mounted engine is always transmitted through a pulley, and the clutchless compressor. A condenser that heats the gaseous refrigerant that has been compressed by the compressor and has become high temperature and high pressure with the outside air to form a high pressure liquid refrigerant, and an expansion valve that adiabatically expands this liquid refrigerant into a low pressure atomized refrigerant, In an automobile air conditioner having an evaporator that vaporizes the low-pressure mist-like refrigerant and cools the air blown into the vehicle compartment, the clutchless compressor includes a suction chamber and a clan.
The first valve port and the discharge chamber that communicate with the crank chamber, and the crank chamber
Control valve for opening / closing the second valve opening
It is composed of a variable capacity swash plate compressor that changes the reciprocating stroke of the piston in the cylinder according to the suction pressure to change the discharge capacity by performing it according to the fluctuation of the suction pressure. A bypass passage that takes in the liquid refrigerant from the end portion of the region and returns the taken-in liquid refrigerant to the clutchless compressor by bypassing at least the expansion valve, and causing the liquid refrigerant to flow down the bypass passage path or down the expansion valve. When the operation of the air conditioner for a vehicle is stopped, the flow passage of the refrigerant is switched from the flow passage through the expansion valve to the flow passage through the bypass passage. A control means for operating the flow path switching means, and the compressor comprising a variable capacity swash plate compressor. The chitchless compressor is provided with a communication hole that communicates the discharge chamber and the crank chamber, and an opening / closing unit that opens and closes the communication hole, and the control unit, when stopping the operation of the vehicle air conditioner, An air conditioner for a vehicle having a clutchless compressor, characterized in that the opening / closing means is controlled so as to open the communication hole so as to connect the discharge chamber and the crank chamber.

[0020]

Claim 2 for achieving the second object.
In the present invention described, the control device controls the opening / closing means to open the communication hole when the operation of the vehicle air conditioner is stopped, and then the flow passage of the liquid refrigerant flows through the bypass passage. It is characterized in that the flow path switching means is operated so as to switch to the flow path.

Further, it is preferable that the bypass passage is configured to return the liquid refrigerant taken in to the clutchless compressor by bypassing the expansion valve and the evaporator.

[0023]

According to the structure of claim 1, when the operation of the vehicle air conditioner is stopped, the flow passage of the refrigerant is switched from the flow passage through the expansion valve to the flow passage through the bypass passage. The refrigerant is not adiabatically expanded by the expansion valve and is returned to the clutchless compressor.
This prevents the evaporator from freezing,
Furthermore , when stopping the operation of the air conditioner for automobiles
A communication hole is opened in the crank chamber and the crank chamber has the same pressure as the discharge chamber.
Therefore, depending on the function of the variable capacity swash plate compressor,
Therefore, the amount of discharged refrigerant is kept to a minimum. According to
Therefore, the required torque is kept at a small value.

[0024]

According to the second aspect of the present invention, when the operation of the vehicle air conditioner is stopped, after the amount of refrigerant discharged from the variable capacity swash plate compressor is minimized,
The flow passage of the liquid refrigerant is switched to the flow passage that flows through the bypass passage. Therefore, the mechanical damage to the clutchless compressor due to the switching of the operating state is reduced, and the durability of the clutchless compressor is improved.

According to the third aspect of the present invention, the liquid refrigerant flows while bypassing the expansion valve and the evaporator when the operation of the vehicle air conditioner is stopped. Therefore, freezing of the evaporator is basically eliminated.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a cooling cycle used in an automobile air conditioner having a clutchless compressor, and FIG. 2 shows a variable capacity swash plate type compressor constituting the clutchless compressor shown in FIG. It is a cross-sectional view of an essential part, and members common to those shown in FIGS. 5 and 6 are denoted by the same reference numerals, and the description thereof is partially omitted.

As shown in FIG. 1, the cooling cycle 70 of the present embodiment includes a clutchless compressor 71 to which the driving force of an on-vehicle engine is constantly transmitted, and a gas compressed by the clutchless compressor 71 to a high temperature and high pressure. A condenser 52 for exchanging heat of the liquid refrigerant with the outside air into a high-pressure liquid refrigerant, and a liquid tank 53 for temporarily storing the liquid refrigerant to remove water and dust in the refrigerant and separate the gas refrigerant and the liquid refrigerant. An expansion valve 54 that adiabatically expands the liquid refrigerant into a low-pressure atomized refrigerant, and an evaporator 55 that vaporizes the low-pressure atomized refrigerant and cools the air blown into the vehicle compartment. 72e (generic name of 72e).

Particularly, in the cooling cycle 70 of the present embodiment, the liquid refrigerant is taken in from the end of the liquid refrigerant region of the cooling cycle 70, the expansion valve 54 and the evaporator 55 are bypassed, and the refrigerant is returned to the compressor 71. A bypass passage 73 is provided. This bypass passage 7
The refrigerant intake port 73a of No. 3 faces the refrigerant pipe 72d between the liquid tank 53 and the expansion valve 54, and the refrigerant outlet port 73a.
b is exposed to the refrigerant pipe 72a on the outlet side of the evaporator 55.

The term "end portion of the liquid refrigerant region" means a portion before the adiabatic expansion of the liquid refrigerant in the expansion valve 54, and the installation position of the bypass passage 73 is limited to the illustrated example. It is not something that will be done. For example, the refrigerant pipe 72c between the condenser 52 and the liquid tank 53
Alternatively, the expansion valve 54 may be modified so that the liquid refrigerant immediately before being adiabatically expanded can be taken out. Further, in order to prevent the evaporator 55 from freezing, it is sufficient to flow the liquid refrigerant at least by bypassing the expansion valve 54. Therefore, the refrigerant outlet port 73b of the bypass passage 73 is connected to the expansion valve 54.
It may be exposed to the refrigerant pipe 72e between the evaporator 55 and the evaporator 55.

Further, in the cooling cycle 70, the liquid refrigerant is made to flow down the bypass passage 73, or the expansion valve 5
4 and a flow path switching means 74 for selectively switching whether to flow down the evaporator 55. As shown in the drawing, the flow path switching means is composed of a three-way valve 74, which is, for example, an electromagnetic valve. The three-way valve 74
Based on an ON signal, which is an external signal, the refrigerant flow passage is operated so as to be a flow passage that flows through the expansion valve 54 and the evaporator 55, and based on the OFF signal, the refrigerant flow passage flows through the bypass passage 73. Is operated.

The flow path switching means 74 is not limited to the illustrated example. For example, a flow path through which the liquid refrigerant flows can be selected by providing an on-off valve on the way of the bypass passage 73 and on the way of the refrigerant conduit 72d between the refrigerant intake port 73a of the bypass passage 73 and the expansion valve 54. Can be switched to each other.

Next, a variable displacement swash plate type compressor which constitutes a clutchless compressor will be described with reference to FIGS.

This variable capacity swash plate compressor is shown in FIG.
As shown in FIG. 5, five cylinder chambers 33 are opened in the cylinder block 30. As shown in FIG. 2, the piston 5 is provided in each of the cylinder chambers 33. A cylinder head 31 and a housing 32 are attached to the cylinder block 30.
The suction chamber 1 into which the refrigerant returned from the evaporator 55 or the bypass passage 73 flows, and the discharge chamber 34 from which the refrigerant sucked from the suction chamber 1 by the piston 5 is compressed and then discharged are formed. The suction port formed in the suction chamber 1 has a suction conduit 7 communicating with the evaporator 55.
2a is connected, and a discharge conduit 72b communicating with the condenser 52 is connected to the discharge port opened in the discharge chamber 34. Then, the refrigerant returned from the evaporator 55 or the bypass passage 73 into the suction chamber 1 through the suction conduit 72a resists the suction valve 37 by the forward movement of the piston 5 into the cylinder chamber 33 formed in the cylinder block 30. Is sucked through the suction port 38 formed in the valve plate 35. On the other hand, the refrigerant compressed by the backward movement of the piston 5 is discharged from the discharge port 6 formed in the valve plate 35 into the discharge chamber 34 against the discharge valve 7 and the discharge conduit 72b.
Through to the condenser 52.

A crank chamber 11 is formed in the housing 32. In this crank chamber 11,
A drive mechanism M for driving the piston 5 and the like are provided, and lubricating oil O for lubricating mechanically sliding parts of the drive mechanism M and the like is filled. Here, the mechanical sliding portion means the drive shaft 18
And the radial bearings 19a and 19b for supporting the thrust bearing 19c, the drive swash plate 17, the thrust bearing 20a and the radial bearing 20b provided between the drive swash plate 17 and the socket plate 16, and the like.

The control valve Cv has the same structure as that described above, and controls the opening and closing of the first valve opening 3 and the second valve opening 4 in accordance with the fluctuation of the heat load of the evaporator 55, that is, the fluctuation of the suction pressure Ps. To do. Control valve Cv
By controlling the opening and closing of the valve openings 3 and 4 by
The reciprocating stroke of the piston 5 is changed according to the suction pressure Ps to control the displacement of the compressor 71.

Furthermore, in the variable displacement swash plate type compressor of this embodiment, as shown in FIGS.
4 and the crank chamber 11, a communication hole 75 is formed in the cylinder block 30 and the valve plate 35. Further, the inlet portion 7 of the communication hole 75 facing the discharge chamber 34
6, an opening / closing means 77 for opening / closing the inlet portion 76 is provided. This opening / closing means is composed of an opening / closing valve 77 such as an electromagnetic valve, and a valve body 79 for opening / closing the inlet portion 76 is provided at the tip of the operating rod 78.

The on-off valve 77 is operated to close the inlet portion 76 of the communication hole 75 on the basis of an on signal which is an external signal, and is operated to open the inlet portion 76 on the basis of an off signal. When the opening / closing valve 77 opens the inlet portion 76 based on the OFF signal, a part of the high pressure refrigerant in the discharge chamber 34 is directly introduced into the crank chamber 11 through the communication hole 75. This allows
The crank chamber pressure Pc is forcibly increased and the inclination angle of the socket plate 16 and the drive swash plate 17 is changed by the action of the moment of the difference between the forces acting on the cylinder side of each piston and the crank chamber 11 side. The minimum tilt angle is determined by the balance with the elastic force of.
That is, by opening the inlet portion 76 with the opening / closing valve 77, the drive swash plate 17 is operated by the action of the control valve Cv.
The drive swash plate 17 and the like are forcibly moved to the position of the minimum tilt angle without waiting for the control of the tilt angle.

As shown in FIG. 1, a three-way valve 74 as a flow path switching means and an opening / closing valve 77 as an opening / closing means.
Is connected to a control device (control means) 80, and the operations of the three-way valve 74 and the opening / closing valve 77 are controlled based on a control signal from the control device 80. An air conditioner switch 81 for instructing the operation or stop of the vehicle air conditioner is connected to the control device 80. The air conditioner switch 81 is provided on a control panel installed on an instrument panel in the vehicle compartment. Further, the motor 83 for driving the blower fan 82 built in the intake unit is also connected to the control device 80, and the air conditioner switch 8
The driving of the motor 83 is turned on and off in conjunction with the on / off operation of 1.

The operation timings of the three-way valve 74 and the opening / closing valve 77 in the control device 80 are set as follows. When the occupant turns off the air conditioner switch 81 and stops the drive motor 83 of the blower fan 82 to stop the operation of the vehicle air conditioner, the control device 80 first outputs an off signal to open the opening / closing valve 77. To do. As a result, the drive swash plate 17 and the like are forcibly moved to the position of the minimum tilt angle. After operating for a predetermined time under this state, the control device 80 operates the three-way valve 74 to switch the flow passage of the refrigerant from the flow passage flowing through the expansion valve 54 and the evaporator 55 to the flow passage flowing through the bypass passage 73. Open / close valve 77
The time from opening the valve to operating the three-way valve 74 is
For example, it is preferable to set it to about 30 seconds.

Next, the operation of this embodiment will be described.

When the occupant turns on the air conditioner switch 81 in order to operate the automobile air conditioner, the blower fan 8
2 starts driving, and the air outside the vehicle compartment or the air inside the vehicle compartment is selectively taken in by the intake unit, and this air is cooled by exchanging heat with the refrigerant flowing through the evaporator 55 built into the cooler unit, and then flows down to the heater unit. To do. In the heater unit, air from the cooler unit is made to flow to the heater core and the detour at a predetermined ratio to reach a predetermined temperature, and then the air is distributed to a predetermined position in the vehicle compartment.

In the cooling cycle 70, the clutchless compressor 71, to which the driving force of the vehicle-mounted engine is constantly transmitted via the belt and the pulley 56, compresses the refrigerant.
The compressed high-temperature high-pressure gaseous refrigerant exchanges heat with the outside air in the condenser 52 to become a high-pressure liquid refrigerant, and this liquid refrigerant is temporarily stored in the liquid tank 53 and mixed into the refrigerant. Water and dust are removed and the gas refrigerant and the liquid refrigerant are separated. The liquid refrigerant flowing out of the liquid tank 53 is stored in the expansion valve 54.
At, adiabatic expansion results in a low-pressure low-temperature atomized refrigerant. The atomized refrigerant exchanges heat with the air blown into the vehicle compartment in the evaporator 55 to be vaporized, and then returns to the suction chamber 1 of the compressor 71. In the cooling cycle 70,
Such a refrigerant flow is repeated.

During operation of the vehicle air conditioner, in the clutchless compressor 71 composed of a variable displacement swash plate compressor, the reciprocating stroke of the piston 5 is changed according to the suction pressure Ps, and the capacity of the discharge amount of the compressor 71 is changed. The control is performed as follows.

The heat load on the evaporator 55 is low and the pressure of the refrigerant returned to the compressor 71, that is, the suction pressure P.
When s is low, the control valve Cv closes the first valve opening 3 and opens the second valve opening 4. Therefore, a part of the high pressure refrigerant discharged into the discharge chamber 34 is partially discharged from the discharge side pressure chamber 8 →
It flows from the second valve port 4 to the first communication passage R1 and is introduced into the crank chamber 11, the inclination angle of the socket plate 16 and the drive swash plate 17 is reduced, and the reciprocating stroke of the piston 5 is reduced. As a result, the amount of discharged refrigerant is reduced, and the amount of refrigerant is appropriate according to the low heat load.

On the other hand, when the heat load on the evaporator 55 is large and the suction pressure Ps is high, the control valve Cv opens the first valve port 3 and closes the second valve port 4.
Therefore, the refrigerant in the crank chamber 11 flows to the suction chamber 1 side through the second communication passage R2, the crank chamber pressure Pc decreases and becomes almost equal to the suction pressure Ps, and the socket plate 16 and the drive swash plate 17 The tilt angle increases and the reciprocating stroke of the piston 5 increases. As a result, the amount of discharged refrigerant increases, and the flow rate of the refrigerant becomes appropriate according to the high heat load.

Next, a case where the operation of the automobile air conditioner is stopped will be described.

When the occupant turns off the air conditioner switch 81, the drive of the blower fan 82 is stopped and the air distribution into the passenger compartment is stopped. The clutchless compressor 71 is constantly transmitted with the drive of the engine, and further, the socket plate 16
Since the drive swash plate 17 has a non-zero inclination angle even at the minimum inclination angle, it slightly performs work and discharges the refrigerant. Therefore, if the atomized refrigerant that has become low in temperature due to adiabatic expansion in the expansion valve 54 continues to flow in the evaporator 55, the evaporator 55 freezes because heat exchange with the air is no longer performed in the evaporator 55. Will be invited.

Therefore, in the vehicle air conditioner of this embodiment, when the operation of the vehicle air conditioner is stopped, the control device 80 first outputs an off signal to the opening / closing valve 77 to open the opening / closing valve 77. . As a result, the opening / closing valve 77 moves backward with respect to the inlet portion 76, and the inlet portion 7 of the communication hole 75 is moved.
6 is opened. Then, a part of the high pressure refrigerant in the discharge chamber 34 is directly introduced into the crank chamber 11 through the communication hole 75, so that the drive swash plate 1 is operated by the control valve Cv.
Even without waiting for the control of the inclination angle of 7 or the like, the drive swash plate 17 or the like is forcibly and quickly moved to the position of the minimum inclination angle.

Further, when the refrigerant is introduced into the crank chamber 11 through the communication hole 75, the lubricating oil is supplied to the mechanical sliding portion of the drive mechanism M and the like, and smooth operation is ensured.

After operating for a predetermined time in this state, the control device 80 outputs an off signal to the three-way valve 74, and the refrigerant flow passage flows from the flow passage that flows through the expansion valve 54 and the evaporator 55 to the bypass passage 73. The three-way valve 74 is operated so as to switch to the flow path. Then, the liquid tank 53
The liquid refrigerant that has flowed out of the compressor is taken into the bypass passage 73 through the three-way valve 74, bypasses the expansion valve 54 and the evaporator 55, is guided to the outlet side refrigerant conduit 72 a of the evaporator 55, and is sucked into the suction chamber 1 of the compressor 71. Return to. Therefore, the adiabaticly expanded low-temperature refrigerant does not flow into the evaporator 55, so that the evaporator 55 does not freeze.

When the automobile air conditioner is not in operation, the communication hole 75 is opened and a part of the high-pressure refrigerant in the discharge chamber 34 is introduced into the crank chamber 11, so that the operating condition of the vehicle fluctuates. However, the drive swash plate 17 and the like are reliably maintained at the position of the minimum inclination angle. Therefore, the required torque of the variable displacement swash plate compressor is kept at a small value, and the fuel efficiency of the vehicle can be improved.

When the air conditioner switch 81 is turned on and switched to the operating state from the stopped state of the automobile air conditioner, the control unit 80 controls the three-way valve 74 and the opening / closing valve 77 in the reverse order of the above procedure. Control operation. That is, first, the control device 80 outputs an ON signal to the three-way valve 74, and controls the three-way valve 74 so that the flow passage of the refrigerant is switched from the flow passage flowing through the bypass passage 73 to the flow passage flowing through the expansion valve 54 and the evaporator 55. Activate. After operating for a predetermined time in this state, the control device 80 outputs an ON signal to the opening / closing valve 77 to close the opening / closing valve 77 to open the communication hole 75.
The entrance 76 of the is closed. After that, the normal operation is performed as described above.

[0055] As described above, according to the automotive air conditioner of this embodiment, capacity variable swash plate compressor 7
Since the cooling cycle 70 can be easily configured by using the clutchless compressor based on 1,
Prevention of freezing of the evaporator 55 can be achieved easily and at low cost.

Further, when the automobile air conditioner is stopped, the on-off valve 77 is opened to introduce a part of the high-pressure refrigerant in the discharge chamber 34 directly into the crank chamber 11 through the communication hole 75. The swash plate 17 and the like are forcibly and quickly moved to the position of the minimum inclination angle. Therefore, even when the operation of stopping the operation of the vehicle air conditioner is performed under the state where the drive swash plate 17 and the like are inclined at the maximum inclination angle, first, the drive swash plate 17 and the like are set to the minimum inclination angle. Since the refrigerant passage is switched to the bypass passage 73 side later, the compressor 71 is less likely to be mechanically damaged, and the durability can be improved.

When the vehicle air conditioner is not in operation, the drive swash plate 17 and the like are reliably maintained at the position of the minimum tilt angle, so that the required torque of the variable capacity swash plate compressor 71 is kept at a small value. The fuel efficiency of the vehicle can be improved.

The lubricating oil circulating in the refrigerant cycle 70 together with the refrigerant is also returned to the compressor 71, so that the durability of the compressor 71 is improved.

[0059]

As described above, according to the first aspect of the present invention, there is provided a vehicle air conditioner having a clutchless compressor based on a variable displacement swash plate compressor, the vehicle air conditioner. Stop working
When opening, the control means opens and closes so that the communication hole is opened.
Since the stage is controlled, the discharge of the variable capacity swash plate compressor
The amount of refrigerant can be reliably minimized, and the required torque
To prevent the evaporator from freezing, while keeping the
Can be achieved.

[0060]

When the operation of the automobile air conditioner is stopped as in the second aspect of the invention, the flow passage of the liquid refrigerant is changed to the bypass passage after the discharge refrigerant amount of the variable capacity swash plate compressor is minimized. By switching to the flow path that flows through, the mechanical damage to the clutchless compressor due to the switching of the operating state is reduced,
It is possible to achieve freeze prevention of the evaporator while further enhancing the durability of the clutchless compressor.

Further, according to the third aspect of the present invention, when the operation of the vehicle air conditioner is stopped, the liquid refrigerant flows by-passing the expansion valve and the evaporator, so that the evaporator is frozen. It can be fundamentally prevented from occurring.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a cooling cycle used in an automobile air conditioner having a clutchless compressor.

FIG. 2 is a cross-sectional view of essential parts showing a variable displacement swash plate type compressor that constitutes the clutchless compressor shown in FIG.

3 is a sectional view of the cylinder block taken along line 3-3 of FIG.

FIG. 4 is a sectional view taken along line 4-4 of FIG.

FIG. 5 is a configuration diagram showing a cooling cycle used in a general automobile air conditioner.

FIG. 6 is a cross-sectional view showing a clutchless type variable displacement swash plate compressor.

[Explanation of symbols]

5 ... Piston 11 ... Crank chamber 33 ... Cylinder 34 ... Discharge chamber 50, 70 ... Cooling cycle 52 ... Condenser 53 ... Liquid tank 54 ... Expansion valve 55 ... Evaporator 56 ... Pulley 71 ... Clutchless compressor (Clutchless type variable capacity swash plate type) Compressor 73 ... Bypass passage 74 ... Three-way valve (flow path switching means) 75 ... Communication hole 77 ... Open / close valve (opening / closing means) 80 ... Control means Cv ... Control valve Ps ... Suction pressure Pd ... Discharge pressure Pc ... Crank chamber pressure

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-58-78051 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60H 1/32 624 F04B 27/14 F04B 35 / 00

Claims (3)

(57) [Claims] 1. The driving force of an in-vehicle engine is a pulley (56).
Clutchless compressor (7
1), a condenser (52) that heat-exchanges the gaseous refrigerant that has been compressed by the clutchless compressor (71) and has become high temperature and high pressure with the outside air to form a high pressure liquid refrigerant, and adiabatic expansion of this liquid refrigerant. An air conditioner for a vehicle, comprising: an expansion valve (54) for converting the low-pressure atomized refrigerant into a low-pressure atomized refrigerant; and an evaporator (55) for cooling the air blown into the vehicle interior by vaporizing the low-pressure atomized refrigerant. Install the compressor (71) in the suction chamber
A first valve port that connects (1) and the crank chamber (11)
(3) and the discharge chamber (34) and the crank chamber (11)
Control valve for opening / closing control of the communicating second valve (4)
It should be performed according to the fluctuation of suction pressure (Ps) by the valve (Cv).
By the piston (5) in the cylinder (33)
The variable displacement swash plate compressor is configured to change the reciprocating stroke of the compressor according to the suction pressure (Ps) to change the discharge capacity. Further, the liquid refrigerant is taken in from the end of the liquid refrigerant region of the cooling cycle (70), A bypass passage (73) for returning the taken-in liquid refrigerant to at least the expansion valve (54) and returning it to the clutchless compressor (71); and flowing the liquid refrigerant through the bypass passage path (73), or the expansion valve (73). 54), the flow path switching means (74) for selectively switching whether or not to flow down the flow path, and the flow path of the refrigerant from the flow path flowing through the expansion valve (54) when the operation of the vehicle air conditioner is stopped. Control means (80) for operating the flow passage switching means (74) so as to switch to the flow passage that flows through the bypass passage (73).
And a communication hole (75) for connecting the discharge chamber (34) and the crank chamber (11) to the clutchless compressor (71) composed of a variable displacement swash plate compressor, and the communication hole (75). An opening / closing means (77) for opening and closing is provided, and the control means (80) communicates the discharge chamber (34) with the crank chamber (11) when the operation of the vehicle air conditioner is stopped. In order to open the communication hole (75), the opening / closing means (77) is controlled so as to open the communication hole (75). 2. The control device (80) controls the communication hole (75) when the operation of the air conditioner for a vehicle is stopped.
After controlling the opening / closing means (77) to open the opening, the flow passage switching means (74) is operated so that the flow passage of the liquid refrigerant is switched to the flow passage flowing through the bypass passage (73). An air conditioner for a vehicle, comprising the clutchless compressor according to claim 1. 3. The bypass passage (73) is configured to return the taken-in liquid refrigerant to the clutchless compressor (71) by bypassing the expansion valve (54) and the evaporator (55). An air conditioner for an automobile, comprising the clutchless compressor according to claim 1 or 2.