JP2008032026A - Compression capacity control device of refrigerating cycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compression capacity control device of a refrigerating cycle with high response, which quickly increases the compression capacity to a predetermined value without time delay when the electromagnetic force of a solenoid-controlled valve is changed. <P>SOLUTION: A capacity control valve 20 allowing a crankcase 12 to communicate with a discharge chamber 4 and closing the crankcase from the discharge chamber is installed so as to keep the pressure difference between the pressure in the pressure regulating chamber 12 and the pressure in the discharge chamber 4 at a predetermined set value. The set pressure difference is changed by changing the electromagnetic force of the capacity control valve 20 so as to control the discharged amount of a refrigerant. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a compression capacity control device for a refrigeration cycle used in an automotive air conditioner or the like.

  Since the compressor used in the refrigeration cycle of the air conditioner for automobiles is directly connected to the engine with a belt, the rotational speed cannot be controlled. Therefore, a variable capacity compressor capable of changing the compression capacity (discharge amount) is used in order to obtain an appropriate cooling capacity without being restricted by the rotational speed of the engine.

  There are so-called swash plate type, rotary type, scroll type, etc. as variable capacity compressors, but here, the piston is reciprocated by rotating a rocking plate provided with variable inclination angle in an airtight crank chamber. A so-called swash plate type will be described as an example.

  In the swash plate type variable capacity compressor, the crank chamber that acts to change the capacity of the compressor when the internal pressure changes is a pressure regulating chamber for controlling the compression capacity, and responds to changes in the suction pressure (Ps). The crank chamber pressure (Pc) is automatically controlled to change the capacity.

  However, in order to perform capacity control based on the suction pressure (Ps) as described above, a flexible membrane material such as a diaphragm or a bellows must be movably disposed in the compression capacity control device. Large scale and high equipment cost.

  Therefore, an electromagnetic control valve is provided for communicating and closing between the crank chamber and the suction chamber so as to keep the differential pressure between the crank chamber pressure (Pc) and the suction pressure (Ps) at a predetermined differential pressure. There is one in which the differential pressure is changed by changing the electromagnetic force of the motor to control the compression capacity (Japanese Patent Laid-Open No. 5-87047). By doing so, the structure is simple and simple, and the cost of the apparatus is reduced.

FIG. 2 is a diagram showing the characteristics of the “enthalpy-refrigerant pressure” of the refrigeration cycle. The compressor is based on the pressure difference (Pc−Ps) between the crank chamber pressure (Pc) and the suction pressure (Ps). When the capacity is controlled, the discharge pressure (Pd) changes accordingly, and thereby the differential pressure (Pc−Ps) between the crank chamber pressure (Pc) and the suction pressure (Ps) further changes. It is repeated by feedback control using as a system. Therefore, when the electromagnetic force of the electromagnetic control valve is changed, there is a drawback that a time delay occurs until the discharge amount reaches a predetermined value, and the compression capacity control is not performed quickly.

  Accordingly, an object of the present invention is to provide a compression capacity control device for a refrigeration cycle having a quick response in which the compression capacity quickly reaches a predetermined value without time delay when the electromagnetic force of the electromagnetic control valve is changed.

In order to achieve the above object, the compression capacity control device of the refrigeration cycle of the present invention compresses the refrigerant sucked from the suction chamber that leads to the low-pressure refrigerant pipe and discharges it to the discharge chamber that leads to the high-pressure refrigerant pipe. In a compression capacity control device of a refrigeration cycle having a variable capacity compressor that changes the discharge amount of refrigerant according to a change in chamber pressure , an electromagnetic control valve that communicates and closes the pressure regulating chamber and the discharge chamber is provided, and electromagnetic control In the valve, the valve body urged in the opening direction by the compression coil spring communicates and closes the pressure regulating chamber and the discharge chamber based on the pressure difference between the pressure in the pressure regulating chamber and the pressure in the discharge chamber. Thus, the pressure in the pressure regulating chamber is changed, whereby the differential pressure is maintained at the set differential pressure set by changing the electromagnetic force of the electromagnetic control valve .

The pressure regulating chamber is an airtightly formed crank chamber, and an oscillating body that is provided with a variable inclination angle with respect to the rotating shaft in the crank chamber and is driven by the rotating motion of the rotating shaft to perform an oscillating motion; It may have a piston that is connected to the rocking body and reciprocates to compress the refrigerant sucked into the cylinder from the suction chamber and discharge it into the discharge chamber .

According to the present invention, so as to maintain the differential pressure between the pressure of the pressure and ejection outlet chamber of the pressure regulating chamber to a predetermined pressure difference, the electromagnetic control valve that communicates and blocks the between the regulating chamber and the discharge chamber is provided Since the set differential pressure is changed by changing the electromagnetic force of the electromagnetic control valve so that the discharge amount of the refrigerant is controlled, it is based on the magnitude of the discharge pressure itself that fluctuates due to the volume control. Therefore, when the electromagnetic force of the electromagnetic control valve is changed, the compression capacity quickly reaches a predetermined value without time delay, and the compression capacity control with quick response is performed. Can do.

Referring to the drawings that explains the embodiment of the present invention.
In FIG. 1, reference numeral 10 denotes a swash plate type variable capacity compressor, which is used in an air conditioning refrigeration cycle of an automobile. As the refrigerant, general R134A or the like is used, but the present invention may be applied to a refrigeration cycle using carbon dioxide as a refrigerant.

  Reference numeral 11 denotes a rotating shaft that is disposed in an airtight crank chamber 12 (pressure-regulating chamber) and is rotationally driven by a driving pulley 13. The rotating shaft 11 is inclined with respect to the rotating shaft 11 and is disposed in the crank chamber 12. The swinging plate 14 swings according to the rotation of the rotating shaft 11.

  A piston 17 is disposed in a reciprocating manner in a cylinder 15 disposed in the periphery of the crank chamber 12, and the piston 17 and the swing plate 14 are connected by a rod 18.

  Therefore, when the swing plate 14 swings, the piston 17 reciprocates in the cylinder 15, and a low-pressure (suction pressure Ps) refrigerant is sucked into the cylinder 15 from the suction chamber 3. The refrigerant that has been compressed to a high pressure (discharge pressure Pd) is discharged into the discharge chamber 4.

  Refrigerant is fed into the suction chamber 3 from the upstream evaporator (not shown) side via the suction pipe 1, and from the discharge chamber 4 to the downstream condenser (not shown) side. High-pressure refrigerant is sent out via the discharge pipe 2.

The inclination angle of the swing plate 14 changes depending on the pressure (Pc) in the crank chamber 12, and the refrigerant discharge amount (that is, the compression capacity) from the cylinder 15 changes depending on the tilt angle of the swing plate 14.
Reference numeral 20 denotes an electromagnetic solenoid control capacity control valve (electromagnetic control valve) for automatically controlling the crank chamber pressure (Pc) to control the compression capacity. 21 is an electromagnetic coil, and 22 is a fixed iron core.

  The movable iron core 23 and the valve body 25 are arranged in a state of passing through the fixed iron core 22 and are connected by a rod 24 that can advance and retreat in the axial direction, and are biased by compression coil springs 27 and 28 from both ends. . Reference numeral 29 denotes an O-ring for sealing.

  The valve seat 26 is formed between the crank chamber communication passage 5 communicating with the crank chamber 12 and the discharge chamber communication passage 6 communicating with the discharge chamber 4, and the valve body 25 is connected to the valve seat from the crank chamber communication passage 5 side. 26 is arranged to face 26. The crank chamber communication path 5 and the suction pipe line 1 communicate with each other through a narrow leak path 7.

  With such a configuration, the differential pressure (Pd−Pc) between the discharge pressure (Pd) and the crank chamber pressure (Pc) acts on the valve body 25 in the opening direction, and the electromagnetic force of the capacity control valve 20 in the closing direction. A force (including the biasing force of the compression coil springs 27 and 28) acts.

  Therefore, in a state where the current value supplied to the electromagnetic coil 21 is constant and the electromagnetic force of the capacity control valve 20 is constant, the pressure difference (Pd−Pc) between the discharge pressure (Pd) and the crank chamber pressure (Pc) varies. Thus, the valve body 25 is opened and closed, and the differential pressure (Pd−Pc) is maintained constant, whereby the crank chamber pressure (Pc) is controlled to a value corresponding to the discharge pressure (Pd), and the compression capacity (discharge amount) is increased. Maintained constant.

  And if the electromagnetic current of the capacity control valve 20 is changed by changing the value of the energization current to the electromagnetic coil 21, the differential pressure (Pd-Pc) kept constant correspondingly changes, and thereby the compression capacity (Discharge amount) is kept constant at different levels.

  That is, when the electromagnetic force of the capacity control valve 20 is decreased, the differential pressure (Pd−Pc) that is kept constant decreases, so that the crank chamber pressure (Pc) increases in a direction approaching the discharge pressure (Pd). The discharge amount becomes small.

  Conversely, when the electromagnetic force of the capacity control valve 20 is increased, the differential pressure (Pd−Pc) that is kept constant increases, so that the crank chamber pressure (Pc) decreases in a direction away from the discharge pressure (Pd). The discharge amount becomes large.

  The compression capacity control performed based on the differential pressure (Pd−Pc) between the discharge pressure (Pd) and the crank chamber pressure (Pc) in this way is the discharge pressure (Pd) that varies directly by the capacity control. Since it is based on the size of itself, feedback control is performed only by the compressor 10 portion. As a result, when the energization current value to the electromagnetic coil 21 changes, there is no time delay until the discharge amount reaches a predetermined value, and rapid compression capacity control is performed.

  The control of the energization current value to the electromagnetic coil 21 is performed by inputting detection signals from a plurality of sensors for detecting various conditions such as an engine, a temperature inside and outside the vehicle, an evaporator sensor, and the like to a control unit 40 incorporating a CPU and the like. A control signal based on the calculation result is sent from the control unit 40 to the electromagnetic coil 21 and performed. The drive circuit for the electromagnetic coil 21 is not shown.

It is a longitudinal cross-sectional view which shows the whole structure of the compression capacity control apparatus of the refrigerating cycle of the 1st Embodiment of this invention. It is a diagram which shows the characteristic of "enthalpy-refrigerant pressure" of a refrigerating cycle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Suction line 2 Discharge line 3 Suction chamber 4 Discharge chamber 5 Crank chamber communication path 6 Discharge chamber communication path 10 Compressor 12 Crank chamber (pressure regulation chamber)
20 Capacity control valve (Electromagnetic control valve)
21 Electromagnetic coil 22 Fixed iron core 23 Movable iron core 25 Valve element 26 Valve seat 28 Compression coil spring

Claims (3)

A variable capacity compressor that compresses the refrigerant sucked from the suction chamber that leads to the low-pressure refrigerant pipe and discharges it to the discharge chamber that leads to the high-pressure refrigerant pipe, and changes the discharge amount of the refrigerant by the pressure change in the pressure regulating chamber; In the compression capacity control device of the refrigeration cycle,
An electromagnetic control valve for communicating and closing between the pressure regulating chamber and the discharge chamber is provided,
In the electromagnetic control valve, the valve body urged in the opening direction by a compression coil spring has a pressure difference between the pressure regulating chamber and the discharge chamber based on a pressure difference between the pressure in the pressure regulating chamber and the pressure in the discharge chamber. The pressure in the pressure regulating chamber is changed by communicating and closing between them, so that the differential pressure is maintained at a set differential pressure set by changing the electromagnetic force of the electromagnetic control valve. A compression capacity control device for a refrigeration cycle. A crank chamber in which the pressure regulating chamber is formed in an airtight manner, a swinging body that is provided with a variable inclination angle with respect to the rotating shaft in the crank chamber and is driven by the rotating motion of the rotating shaft to swing. 2. The compression capacity control device for a refrigeration cycle according to claim 1, further comprising a piston that is reciprocally connected to the rocking body to compress refrigerant sucked into the cylinder from the suction chamber and discharge the refrigerant into the discharge chamber. Capacity control of a variable capacity compressor that compresses the refrigerant sucked from the suction chamber that leads to the low-pressure refrigerant pipe and discharges it to the discharge chamber that leads to the high-pressure refrigerant pipe and changes the discharge amount of the refrigerant according to the pressure change in the pressure regulating chamber In the valve
  A valve seat formed between a first space communicating with the discharge chamber and a second space communicating with the pressure regulating chamber;
  A valve element disposed to open and close the valve seat in the second space;
  A compression coil spring that biases the valve body in the opening direction;
  An electromagnetic solenoid for setting a set differential pressure at which the differential pressure between the pressure in the discharge chamber and the pressure regulating chamber should be kept constant by urging the valve body in the closing direction by electromagnetic force;
  A capacity control valve for a variable capacity compressor.

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