JPH10184568A - Scroll compressor and its back pressure chamber pressure control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control pressure in a back pressure chamber minutely with a simple structure and with a good efficiency by providing with a pressure control means for controlling intermediate pressure for push-pressing a scroll toward the other scroll and applied in the back pressure chamber, to a target value which is decided by a function of a pressure ratio between intake pressure and discharge pressure. SOLUTION: In a back pressure chamber pressure control system, intermediate pressure between discharge pressure detected by a discharge pressure detecting means 111 and intake pressure detected by an intake pressure detecting means 112, is supplied to a back pressure chamber 82 through a back pressure control valve 100 which communicates with discharge piping 101 and intake piping 102, and non-turning scroll 51 which is floating supported is pushed toward a turning scroll 61. A target value of intermediate pressure applied on the back pressure chamber 82 is calculated by a controller 110 as the function of a pressure ratio between discharge pressure and intake pressure, it is detected by a back pressure chamber detecting means 113 whether real pressure in the back pressure chamber 82 attains a target value or not, and intermediate pressure is controlled by a controller 110 so as to match with the target value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor in which a back pressure is controlled so as to keep a gap at a tip of a wrap at an appropriate value in response to a change in a thrust force between a non-orbiting scroll and an orbiting scroll due to a change in a compression ratio. More particularly, the present invention relates to a scroll compressor that changes a back pressure in accordance with a change in a compression ratio and a back pressure chamber pressure control valve thereof.

[0002]

FIG. 6 is a diagram of a first example of the prior art,
FIG. 1 is a diagram of a vertical section and a back pressure control system of a scroll compressor disclosed in Japanese Patent Application Laid-Open No. 3-258895. In the figure, a compression mechanism 2
However, electric motors 3 are disposed below, and a lubricating oil reservoir 4 is formed at the bottom of the sealed housing 1. The compression mechanism 2 has a configuration in which a non-orbiting scroll 5 having a spiral wrap 5a on an end plate and a wrap of a orbiting scroll 6 also having a spiral wrap 6a on an end plate are combined. The orbiting scroll 6
An Oldham ring 8 for preventing rotation of the orbiting scroll 6 is provided between the frame and the frame 7. The electric motor 3 makes the orbiting scroll 6 orbit via a shaft 9. The shaft 9 is supported by a main bearing 10 and a lower bearing 11 provided on the frame 7, and its eccentric pin is fitted to a turning bearing 12 provided on the back of the turning scroll.

A main bearing 10 and a lower bearing 1 are provided in a shaft 9.
An oil supply passage 13 that guides the lubricating oil to the bearing 1 and the slewing bearing 12 is provided, and an oil supply device that sucks up the lubricating oil in the oil sump 4 and sends it to the oil supply passage 13 is provided at the shaft end of the shaft 9.

In this scroll compressor, an electric motor 3
When the orbiting scroll 6 is orbitally driven through the shaft 9, the refrigerant gas sucked through the suction port 15 from the suction pipe 14 is supplied to the fixed scroll 5 and the orbiting scroll 6.
Compressed by the action. At this time, part of the refrigerant gas flows from the compression chamber during the compression process through the communication hole 16 into the back pressure chamber 17. For this reason, the pressure in the back pressure chamber becomes an intermediate pressure between the suction pressure and the discharge pressure, and presses the orbiting scroll 6 against the non-orbiting scroll 5.

The compressed refrigerant gas is supplied to the non-orbiting scroll 5
Is discharged from a discharge port 18 at the center of the upper part of the frame 7, passes through a passage 19 formed of an axial (vertical) groove provided on the outer peripheral portion of the frame 7, cools the electric motor 3, and passes through a discharge port 20. It flows out to the discharge pipe 21. The suction pipe 14 and the discharge pipe 21 include a suction sensor 22 and a discharge sensor 23 which are pressure elements for converting respective pressures (suction pressure and discharge pressure) into current or voltage. Connected.

The integrated circuit 24 calculates the optimum pressure in the back pressure chamber 17 for the suction pressure and the discharge pressure based on the electric signals sent from the suction sensor 22 and the discharge sensor 23. On the other hand, the integrated circuit 24 calculates the actual pressure in the back pressure chamber 17 based on the suction pressure and the discharge pressure, the position of the communication hole 16, and the like. On the other hand, the back pressure chamber 17 and the discharge pipe 21
And a bypass pipe 27 for connecting the
Reference numeral 7 denotes a hydrodynamic resistance means (in this example, a capillary tube 2).
8) and a solenoid valve 26 are provided.

When the actual pressure calculated by the integrated circuit 24 becomes lower than the optimum pressure by a certain level or more, the integrated circuit 24 opens the solenoid valve 26 and opens the discharge pipe 21 and the back pressure chamber 1.
7 is communicated. Thereby, a part of the refrigerant gas in the discharge pipe 21 flows into the back pressure chamber 17. For this reason, the pressure in the back pressure chamber 17 causes a pressure rise corresponding to the length and the inner diameter of the capillary 28, approaches the optimum pressure, and pushes down the gas for the orbiting scroll 6 during the compression process in the scroll. The pushing force of the gas in the back pressure chamber 17 is balanced, and the orbiting scroll 6 is operated without detaching from the non-orbiting scroll 5.

That is, in this embodiment, a communication hole 16 for connecting a compression chamber formed by both scrolls and a back pressure chamber 17 of the orbiting scroll is provided in the end plate of the orbiting scroll. Are communicated via a path via a solenoid valve and a resistance means, and when one or both of a predetermined suction pressure and a discharge pressure are sensed, the solenoid valve is opened and the back pressure chamber 17 is opened.
Means for increasing the pressure in proportion to the discharge pressure.

FIG. 7 is a diagram of a second example of the prior art, and is a control system diagram of an actuator section of a vehicle clutch drive unit disclosed in Japanese Patent Publication No. 7-56308.
This is not related to scroll compressors, but is cited because it includes techniques available for pressure control.

In FIG. 1, the actuator section includes a pressure source 31 in which air as a compressible fluid is stored in a compressed state, a hydraulic cylinder 32, and first and second normally closed solenoid valves 33 and 34. And a pressure adjusting device 35 comprising: The fluid pressure cylinder 32 is a cylinder tube 32
a having a piston 36 housed therein.
Is biased by a spring 37 in the direction of arrow X. The chamber 38 of the cylinder tube 32a is connected to the pressure adjusting device 35, and the compressed air from the pressure source 31 is supplied to the chamber 38 by opening only the first normally closed solenoid valve 33. Thus, the pressure in the chamber 38 rises and the piston 3
When the lever 6 is moved in the direction of the arrow Y against the force of the spring 37, the clutch release lever connected to the operating rod 39 is operated, and the clutch is operated in the direction of disengaging the clutch. On the other hand, when only the second normally closed solenoid valve 34 is opened, the chamber 38 is opened to the atmospheric pressure, the piston 36 moves in the direction of the arrow X, and the clutch is operated in the direction for connecting the clutch. Opening / closing control of these electromagnetic valves 33, 34 is performed in response to a pulse signal applied to each of the exciting coils 33a, 34a. That is, the drive signal is
It is composed of a first pulse signal Pa for opening and closing control of the first normally closed solenoid valve 33 and a second pulse signal Pb for opening and closing control of the second normally closed solenoid valve 34. Applies the first pulse signal Pa to the exciting coil 33a, thereby opening and closing the first normally closed solenoid valve 33 in a pattern corresponding to the waveform of the first pulse signal Pa, and intermittently compressing air pressure into the chamber 38. Put in. On the other hand, when the clutch is engaged, the second pulse signal Pb is
a, whereby the second normally closed solenoid valve 34 is opened and closed in a pattern corresponding to the waveform of the second pulse signal Pb, and an operation of intermittently releasing the pressure in the chamber 38 is performed.

That is, in this embodiment, as an actuator using a compressible fluid, an actuator for controlling the opening and closing time of a solenoid valve for supplying a fluid from a pressure source and a solenoid valve for discharging a fluid from a controlled space are controlled. It is.

A third example of the prior art is Japanese Utility Model Laid-Open No. 5-1457.
No. 9. This is because, in a scroll compressor in which a fixed scroll or an orbiting scroll is pressed against the other scroll by the pressure of a fluid introduced into a back pressure chamber formed on the back side of either scroll, A load sensor is provided on the contact surface between the fixed scroll and the orbiting scroll to suppress indoor pressure fluctuations, always maintain the optimal back pressure load regardless of changes in operating conditions, and enable high-efficiency operation. And a valve for controlling the pressure in the back pressure chamber so that the load on the contact surface detected by the sensor enters the optimum efficiency zone.

[0013]

The first conventional example has the following disadvantages. (1) Since the refrigerant supplied from the discharge pressure section to the back pressure chamber flows into the closed space formed by the two scrolls and is discharged after being compressed, power consumption increases and efficiency decreases. (2) The pressure in the back pressure chamber acts on the back pressure chamber area by applying a force equal to the sum of the thrust force generated by the pressure and the area in each of the plurality of closed spaces formed by the non-orbiting scroll and the orbiting scroll. The pressure required is desirable. However, the pressure of the refrigerant supplied to the back pressure chamber is determined by the characteristics of the resistance means set in advance and the resistance of the communication hole connecting the closed space formed by the back pressure chamber and the scroll. Discharge pressure. Further, the discharge pressure is mainly determined by the outside air temperature, and the suction pressure is determined by the evaporator temperature, so that the suction pressure and the discharge pressure change independently of each other. The thrust generated by the scroll is a function of the suction pressure and the discharge pressure. Thus, since there is a difference between the required pressure of the back pressure chamber pressure and the actual supply pressure, the control of the gap at the tip of the wrap becomes incomplete.

When the second conventional example is applied to a scroll compressor, since the volume of the back pressure chamber as the controlled space is extremely small, the controlled space is controlled by the operation of the supply-side solenoid valve or the discharge-side solenoid valve. There is a drawback that the pressure response is large and an arbitrary pressure intermediate between the supply pressure and the discharge pressure cannot be created.

In the third conventional example, there is a disadvantage that the structure of the load sensor installation portion on the contact surface between the end plates of both scrolls is complicated. In addition, in the literature disclosing this example,
The structure of the valve is not shown.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the above-mentioned techniques, and thereby provides a scroll compressor and a back-pressure chamber control valve which can efficiently control the back-pressure chamber pressure with a simple structure and can control the back-pressure chamber pressure finely. It is intended to provide.

[0017]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems and relates to a scroll compressor having the following features and a back pressure chamber pressure control valve thereof.

(1) A pair of a non-orbiting scroll and an orbiting scroll are meshed with each other, and the orbiting scroll is driven to revolve orbit, so that the volume of a compression chamber formed between the two scrolls is sequentially reduced to compress gas. In the scroll compressor, a back pressure chamber that applies an intermediate pressure between the suction pressure and the discharge pressure to at least the back surface of the one scroll and presses the scroll axially toward the other scroll is formed. A scroll compressor comprising pressure control means for controlling an intermediate pressure applied to a back pressure chamber to a target value determined by a function of a pressure ratio between a suction pressure and a discharge pressure.

(2) The pressure control means detects the suction pressure and the discharge pressure, calculates the pressure ratio, and calculates the target value from a predetermined function based on the pressure ratio.
A controller that outputs a control signal after comparing with the pressure in the back pressure chamber; and supplies an output signal from the controller and supplies a set amount of discharge gas into the back pressure chamber, or sets a set amount of gas in the back pressure chamber. The scroll compressor according to the above (1), further comprising a control valve that discharges the pressure in the back pressure chamber to the target value by discharging the pressure to the suction side.

(3) The control valve includes a valve body movable to three positions and a cavity having a set volume provided in the valve body, and the cavity is formed by moving the valve body. Switching between the back pressure chamber, the suction side, and the discharge side to supply the back pressure chamber with an amount of gas corresponding to the volume of the cavity for each movement, or The scroll compressor as described in the above item (2), wherein the scroll compressor is exhausted from the outlet.

(4) A valve body, a valve body movably provided at three positions in the valve body, a drive mechanism for moving the valve body to three positions, and a valve body provided at the valve body A hollow portion having a set volume, and three different pressure connection ports provided in the valve body and separately connected to the hollow portion when the valve body moves to three positions, respectively. By moving, after connecting the hollow portion to any of the connection ports, by switching and connecting to another adjacent connection port,
A back pressure chamber pressure control valve for a scroll compressor, wherein gas is supplied and exhausted by moving an amount of gas corresponding to the volume of the valve body cavity for each switching movement.

(5) The driving mechanism is a pair of electromagnetic coils, and by energizing / de-energizing the same pair of electromagnetic coils,
(4) The valve body described above, wherein the valve body is held by a carrier made of a slidable magnetic material, and the valve body is slidable to three positions by controlling the energization of the electromagnetic coil. Back pressure chamber pressure control valve for scroll compressor.

(6) The driving mechanism is a stepping motor, the valve body is mounted on a rotating shaft of the stepping motor, and the valve body is rotatable to three positions by rotation control of the stepping motor. A back pressure chamber pressure control valve for a scroll compressor according to the above mode (4).

[0024]

FIG. 1 is a longitudinal sectional view of a main part of a hermetic scroll compressor according to an embodiment of the present invention, and is a diagram of a back pressure control system. First, the configuration of the compressor section will be described. In the figure, 41 is a closed housing, 42 is a suction port provided on the side of the housing, 43 is a discharge cover provided on the top of the housing, 44
Is a discharge port provided in the cover, and 45 is a frame fixedly held in the housing. 51 is a non-orbiting scroll, 52 is an end plate, 53 is a spiral wrap provided on the end plate, and 54 is a discharge port provided on the end plate. 61 is an orbiting scroll, 62 is its end plate, 63 is a spiral wrap provided on the end plate, 64
Is a boss provided on the end plate. The spiral wraps of the two scrolls mesh with each other to form a compression chamber 65 therein. Reference numeral 71 denotes a shaft, and 72 denotes an upper bearing provided on the frame. The upper bearing rotatably supports the shaft 71 together with a lower bearing (not shown). The shaft is driven by an electric motor (not shown). 73
Is an eccentric pin provided at the tip of the shaft;
Reference numeral 4 denotes a slewing bearing provided on the boss 64 of the slewing bearing and fitted with an eccentric pin; 75, a thrust bearing provided on the frame 45 for receiving the thrust of the slewing scroll; An Oldham ring that is provided in between and prevents rotation of the orbiting scroll and allows revolving. 81 is a floating support portion provided on the frame for floatingly supporting the non-orbiting scroll, 82 is a back pressure chamber provided between the non-orbiting scroll 51 and the discharge cover 43, and 83 is a pressure supply to the back pressure chamber. The back pressure chamber communication hole is provided in the discharge cover to perform the operation.

In this compressor, the rotation of the shaft 71 causes the orbiting scroll to revolve by the action of the eccentric pin 73 and the Oldham ring 76. Refrigerant gas is sucked from the suction port 42, enters the compression chamber from the outer periphery of the both meshing portions via a passage (not shown), is compressed by the inward movement of the compression chamber, and is compressed by the discharge port 54 and the discharge port 44.
Is discharged to the outside. In the process of compressing the refrigerant, the non-orbiting scroll and the orbiting scroll move in directions away from each other due to the pressure of the compressed refrigerant gas, thereby reducing the compression efficiency. In order to prevent this, gas pressure is supplied from the outside to the back pressure chamber 82 through the back pressure chamber communication hole 83, and the non-orbiting scroll, which is floatingly supported, is pressed against the orbiting scroll.

Next, the configuration of the back pressure chamber pressure control system will be described. In FIG. 1, 100 is a back pressure control valve, 101 is a discharge pipe connected to the discharge port 44, 102 is a suction pipe connected to the suction port 42, 103 is a supply pipe connecting the discharge pipe 101 and the control valve 100, and 104 is a supply pipe. A discharge pipe 105 connecting the suction pipe 102 and the control valve 100, and a back pressure chamber communication hole 83 connected to the back pressure chamber 82
Back pressure pipe connecting the control valve 100 and the control valve 100; 110, a controller; 111, a discharge pressure detecting means connected to the discharge pipe 101;
12 is a suction pressure detecting means connected to the suction pipe 102, 113
Is a back pressure chamber pressure detecting means connected to the back pressure pipe 105, and 114 is a control signal output means for sending a command signal from the controller 110 to the control valve 100.

This control system determines the intermediate pressure between the discharge pressure detected by the discharge pressure detecting means 111 and the suction pressure detected by the suction pressure detecting means 112 by using a back pressure control valve connected to the discharge pipe and the suction pipe. The non-orbiting scroll 51, which is supplied to the back pressure chamber 82 via 100 and is supported by floating, presses the orbiting scroll 61 toward the orbiting scroll 61. The target value of the intermediate pressure applied to the back pressure chamber is calculated by the controller 110 as a function of the pressure ratio between the discharge pressure and the suction pressure, and determines whether the actual pressure of the back pressure chamber has reached this target value. The pressure is detected by the pressure chamber pressure detecting means 113 and is controlled by the controller 110 so as to match the target value.

FIGS. 2A and 2B are two views of the first embodiment of the back pressure control valve 100, wherein FIG. 2A is a longitudinal sectional view and FIG. 2B is a horizontal sectional view. This is a three-position switching solenoid valve. In the figure, 103 is the aforementioned supply pipe, 104 is the discharge pipe, and 105 is the back pressure pipe. 201 is a supply valve cylinder, 202 is a lid of the cylinder 201 connected to the supply pipe 103, 203 is a valve port, and the inner peripheral edge is a valve seat. Reference numeral 204 denotes a ball valve, and reference numeral 205 denotes a spring that presses the ball valve against a valve seat.
A supply valve 206 is configured by the above components. At a position symmetrical with the supply valve 206, a symmetrical discharge valve 206 'is provided.
Is configured. The discharge valve 206 ′ includes a cylinder 201 ′, a lid 202 ′, and a valve port 20 corresponding to each part of the supply valve 206.
3 ', a ball valve 204' and a spring 205 '.

Reference numeral 211 denotes the cylindrical bodies 201 and 201 'on both sides.
Is a base fixed to a lower side of the inner surface of the cylinder. Reference numeral 213 denotes a through hole provided at the center of the base, and the lower end thereof communicates with the back pressure tube 105. 21 shown in FIG.
Reference numerals 4 and 214 ′ denote grooves provided at symmetrical positions with the through hole 213 interposed therebetween, and both ends thereof open to the internal space of the cylinder 211. Reference numeral 221 denotes a carrier which is loosely fitted inside the cylinder 211 so as to be movable in the axial direction, and is made of a magnetic material. Reference numeral 222 denotes a slide valve that is loosely fitted in the concave portion of the carrier.
Reference numeral 3 denotes a pressing spring for pressing the slide valve toward the base 212, reference numeral 224 denotes a hollow provided at the center of the slide valve 222, and reference numerals 225 and 225 'denote carriers 22.
The rods 226 and 226 'provided on both sides of 1 are balancing springs provided between the carrier 221 and the left and right cylinders 201 and 201'. When the electromagnetic coil described later is de-energized, the left and right forces of the carrier 221 are balanced by the balance spring, and the carrier 221 occupies a central position in the cylinder 211, and the cavity 224 and the through hole 213 of the base face each other. 227
Is a central valve chamber formed in the cylinder. This is a space where both ends are limited by the valve ports 203 and 203 'on both sides. In the figure, the left and right spaces of the base and the carrier communicate with each other on the sides of the base 212 and the carrier 221, so that the left and right spaces of the base and the carrier form an integrated central valve chamber 227. Since the carrier 221 is loosely fitted in the central valve chamber 227, it can move in the central valve chamber in the left-right direction in the figure.
Both ends of the grooves 214, 214 'are always open to the central valve chamber space. 231, 231 'are a pair of electromagnetic coils provided in the cylinder side part.

In the three-position switching solenoid valve, the two electromagnetic coils are not energized or, when energized, are always selectively energized on one side only. Thereby, this solenoid valve can take three states.

(1) De-energization: FIG. 2 shows the non-energized state of the electromagnetic coil. The carrier 221 is a balance spring 22
6, 226 ′, it is located at the center of the central valve chamber 227, and the cavity 224 of the slide valve 222 communicates with the through hole 213 of the base 212. The through hole 213 is a hole communicating with the back pressure chamber 82 of the scroll compressor.

(2) Energizing the right electromagnetic coil 231 in FIG. 2: At this time, a magnetic force acts on the gap between the cylinder 211 and the carrier 221, and the carrier moves rightward in FIG. Cavity 224 is the base 212
Stop at a position overlapping the groove 214 of FIG. At this time, the ball valve 204 is pushed rightward by the rod 225 to be separated from the valve seat, and the valve port 203 is opened. As a result, the central valve room 2
27 communicates with the discharge pipe 101 (FIG. 1),
The pressure of 7 becomes the discharge pressure (high pressure), and the pressure of the cavity 224 of the slide valve becomes the discharge pressure (high pressure) via the groove 214. At this time, the through hole 213 connected to the back pressure chamber 82 (FIG. 1) is closed by the slide valve 222.

(3) Energizing the left electromagnetic coil 231 'in FIG. 2: At this time, a magnetic force acts on the gap between the cylinder 211 and the carrier, the carrier 221 moves to the left in the figure, and the slide valve The cavity 224 of 222 is the base 21
It stops at the position overlapping the second groove 214 '. At this time, the rod 225 'pushes the ball valve 204' to the left and separates from the valve seat, opening the valve port 203 '. As a result, the central valve chamber 227 communicates with the suction pipe 102 (FIG. 1), the pressure of the central valve chamber 227 becomes the suction pressure (low pressure), and the pressure of the slide valve cavity 224 becomes the suction pressure (low pressure) via the groove 214 '. ). At this time, the through hole 213 connected to the back pressure chamber 82 (FIG. 1) is closed by the slide valve 222.

By the above three operations, the cavity 224 is formed.
Communicates with the back pressure chamber when not energized, communicates with the discharge pipe when the electromagnetic coil 231 is energized, and communicates with the suction pipe when the electromagnetic coil 231 'is energized. By performing this operation between two adjacent stationary positions, the refrigerant at the discharge pressure is supplied to the back pressure chamber by the cavity 224.
And the pressure of the back pressure chamber pressure corresponding to the volume of the cavity 224 can be discharged from the back pressure chamber to reduce the pressure. By repeating this operation, the refrigerant is supplied to the back pressure chamber little by little or discharged from the back pressure chamber,
The back pressure chamber pressure can be any pressure between the discharge pressure and the suction pressure.

FIG. 3 is a functional block diagram of the back pressure control device. The discharge pressure Pd is detected by the discharge pressure detecting means 111.
The suction pressure Ps is detected by the suction pressure detecting means 112, the pressure ratio φ = Pd / Ps and the back pressure chamber target value Pmo = f (φ) are calculated and stored in the controller 110, and are stored. Pmo and back pressure chamber pressure detecting means 11
3 to compare with the actual value Pm of the back pressure chamber,
A control signal is output to the back pressure control valve 100 via the control signal output means 114 so that the actual pressure Pm of the back pressure chamber approaches the target value Pmo. The valve driving means includes electromagnetic coils 231 and 23
1 '. The target value Pmo of the back pressure chamber pressure is given by an upwardly convex quadratic function relating to the pressure ratio φ: Pmo = aφ ² + bφ + c, a <0.

FIG. 4 is a flowchart of the control performed by the above function. The detection of the discharge pressures Pd and Ps, the calculation of the pressure ratio φ, and the calculation of the target value Pmo of the back pressure chamber pressure are performed, the pressure Pm of the back pressure chamber is detected, and the difference ΔPm = Pm
-Pmo is required. When ΔPm is larger than the predetermined error ε and positive (the actual value is larger than the target value), the back pressure control valve is driven to the discharge side. When ΔPm is larger than the predetermined error ε and negative (the actual value is smaller than the target value), the back pressure control valve is driven to the supply side. In each case, the back pressure chamber pressure Pm is detected, and the process is repeated until the back pressure chamber pressure falls within the error of the target value (| ΔPm | ≦ ε). If the back pressure chamber pressure falls within the error of the target value, the discharge pressure P of the compressor
d. Return to the beginning of the flow chart and repeat the above process in preparation for fluctuations in the suction pressure Ps.

FIGS. 5A and 5B are two views of a second embodiment of the back pressure control valve 100 in the above embodiment (FIG. 1), wherein FIG. 5A is a longitudinal sectional view, and FIG. It is sectional drawing. This control valve is a three-position switching stepping motor driven electric valve. In the figure, the upper half is a drive motor unit, and the lower half is a valve unit.

In the upper half drive motor section, 301 is a motor housing, 302 is a motor stator, 303 is a motor rotor, 304 is a shaft, 305 is a ball bearing that supports the shaft, and 306 supplies current to the motor. It is an electric wire. These components constitute a drive motor unit.

In the lower half valve section, 311 is a container of the valve section, and 312 is a supply pipe 10 connected to a lower portion of the valve section container.
3 and the other end thereof communicates with the discharge pipe 101 (FIG. 1). Reference numeral 105 denotes a back pressure pipe communicating with the back pressure chamber 82 (FIG. 1). Although not shown in FIG. (A), in FIG. (B), together with the supply pipe 103 and the back pressure pipe 105, the discharge pipe 10 is indicated by a dotted line.
4 are also shown. Supply pipe 103, discharge pipe 1
04, the back pressure pipe 105 is opened to the inside of the valve container by communication holes 103 ', 104', 105 'on the bottom surface of the valve container. In FIG. 7A, reference numeral 312 denotes a disk provided inside the valve container. This disk is connected to and driven by the shaft 304 of the motor. Reference numeral 313 denotes a pivot fixed to the center of the bottom surface of the valve container, which is inserted into a concave hole on the lower surface of the disk 312 and holds the center of rotation of the disk. Reference numeral 314 denotes a stopper fixed near the outer periphery of the inner surface of the valve container, and engages with the notch 315 shown in FIG. In FIG. (B), the disk 312 includes
When the motor is not energized, the back pressure pipe communication hole 10
A cavity 316 is provided at a position corresponding to 5 ′.

The stepping motor rotates by the number of supplied pulsed voltages in units of an angle defined by the number of poles. Since the shaft 304 rotates at an angle corresponding to the rotation angle, the disk 312 also rotates by the same angle. Further, by changing the direction of the phase difference of the pulsed voltage supplied to the stepping motor, the direction of rotation can be changed. By utilizing these functions, the cavity 316 on the lower surface of the disk can be made to correspond to one of the supply pipe communication hole 103 ', the discharge pipe communication hole 104', and the back pressure pipe communication hole 105 '. By this operation, the first
As in the case of the example, the refrigerant in the back pressure chamber 82 is increased or decreased,
The pressure in the back pressure chamber can be appropriately controlled.

[0041]

According to the present invention, a three-position switching solenoid valve or a three-position switching electric valve, which is controlled while detecting the pressure of each part by a controller, is used to move the discharge pressure to the back pressure chamber by moving a small cavity defined in advance. Supply the same amount of refrigerant or discharge the same amount of refrigerant at the back pressure chamber pressure,
The back pressure chamber pressure is arbitrarily controlled, the gap between the wraps of the orbiting scroll and the non-orbiting scroll is properly maintained, and the scroll compressor can be operated in a good state.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view and a back pressure chamber pressure control system diagram of a scroll compressor according to an embodiment of the present invention.

FIGS. 2A and 2B are diagrams showing a first embodiment of a back pressure chamber pressure control valve and a drive unit thereof in the embodiment, where FIG. 2A is a longitudinal sectional view and FIG. 2B is a horizontal sectional view.

FIG. 3 is a functional block diagram in the embodiment.

FIG. 4 is a control flowchart in the embodiment.

FIGS. 5A and 5B are diagrams showing a second embodiment of the back pressure chamber pressure control valve and the driving unit thereof in the embodiment, where FIG. 5A is a longitudinal sectional view and FIG. 5B is a sectional view taken along line AA of FIG. .

FIG. 6 is a diagram of a first example of the prior art, showing a longitudinal sectional view of a scroll compressor and a system diagram of a back pressure chamber pressure control.

FIG. 7 is a diagram of a second example of the related art, and is a control system diagram of an actuator section of a vehicle clutch drive unit.

[Explanation of symbols]

 41 Housing 42 Inlet 43 Discharge cover 44 Discharge port 45 Frame 51 Non-orbiting scroll 52 End plate 53 Spiral wrap 61 Orbiting scroll 62 End plate 63 Spiral wrap 64 Boss 65 Compression chamber 81 Floating support part 82 Back pressure chamber 83 Back Pressure chamber communication hole 100 Back pressure control valve 101 Discharge pipe 102 Suction pipe 103 Supply pipe 103 'Supply pipe communication hole 104 Drain pipe 104' Drain pipe communication hole 105 Back pressure pipe 105 'Back pressure pipe communication hole 110 Control device (Controller) 111 Discharge Pressure detecting means 112 Suction pressure detecting means 113 Back pressure chamber pressure detecting means 114 Control signal output means 201, 201 'Cylindrical body 202, 202' Lid 203, 203 'Valve port 204, 204' Ball valve 205, 205 'Spring 211 Cylinder 212 Base 213 Penetration 214, 214 'Groove 221 Carrier 222 Slide valve 223 Pressing spring 224 Cavity 225, 225' Rod 226, 226 'Balancing spring 227 Central valve chamber 301 Motor container 302 Stator 303 Rotor 304 Shaft 305 Ball bearing 306 Electric wire 311 Valve container 312 Disk 313 Pivot 314 Stopper 315 Notch 316 Cavity

Claims (6)

[Claims] 1. A scroll for compressing gas by meshing a pair of a non-orbiting scroll and an orbiting scroll and driving the orbiting scroll to revolve orbit, thereby sequentially reducing the volume of a compression chamber formed between the two scrolls. In the compressor, a back pressure chamber for applying an intermediate pressure between the suction pressure and the discharge pressure to at least the back surface of the one scroll and pressing the scroll in the axial direction toward the other scroll is formed. A scroll compressor comprising pressure control means for controlling an intermediate pressure applied to a pressure chamber to a target value determined by a function of a pressure ratio between a suction pressure and a discharge pressure. 2. The pressure control means detects a suction pressure and a discharge pressure and calculates a pressure ratio thereof, and calculates the target value from a predetermined function based on the pressure ratio. A controller that outputs a control signal after comparison with the pressure of the controller, and receives an output signal from the controller and supplies a set amount of discharge gas into the back pressure chamber, or supplies a set amount of gas in the back pressure chamber to the suction side. 2. The scroll compressor according to claim 1, further comprising a control valve for discharging the pressure in the back pressure chamber to approach the target value. 3. The control valve includes a valve body movable to three positions and a cavity having a set volume provided in the valve body, and the cavity is moved by moving the valve body. The back pressure chamber,
Switching connection between the suction side and the discharge side, and for each movement,
3. The scroll compressor according to claim 2, wherein an amount of gas corresponding to the volume of the cavity is supplied to or exhausted from the back pressure chamber. 4. A valve body, a valve body movably provided at three positions in the valve body, a drive mechanism for moving the valve body to three positions, and a setting provided on the valve body The valve body includes a cavity having a volume, and three different pressure connection ports which are provided in the valve body and communicate with the cavity separately when the valve moves to three positions. Thereby, after connecting the hollow portion to any of the connection ports,
A scroll, characterized in that by switching connection to another adjacent connection port, each time a switching movement is performed, an amount of gas corresponding to the volume of the valve body cavity is moved, and air supply and exhaust are performed. Back pressure chamber pressure control valve for compressor. 5. The driving mechanism is a pair of electromagnetic coils,
By energizing / de-energizing the pair of electromagnetic coils, the valve body is held by a carrier made of a slidable magnetic material.
The back pressure chamber pressure control valve of a scroll compressor according to claim 4, wherein the back pressure chamber can be slid to a position. 6. A stepping motor as the driving mechanism, wherein the valve element is mounted on a rotation shaft of the stepping motor, and the valve element is rotatable to three positions by rotation control of the stepping motor. Claim 4
A back pressure chamber pressure control valve for a scroll compressor according to item 1.