CN1936334A

CN1936334A - Variable capacity type rotary compressor and control method thereof

Info

Publication number: CN1936334A
Application number: CN 200610122631
Authority: CN
Inventors: 邵海波
Original assignee: Midea Group
Current assignee: Guangdong Meizhi Compressor Co Ltd
Priority date: 2006-09-30
Filing date: 2006-09-30
Publication date: 2007-03-28
Anticipated expiration: 2026-09-30
Also published as: CN100441872C

Abstract

A variable-capacity rotary compressor is composed of two cylinders A and B with different working volumes, piston and slide plate in each cylinder, partition between cylinders, eccentric crankshaft for driving piston, and upper and lower bearings for supporting crankshaft. The control valve device comprises a valve seat arranged in a valve shell, a slide block pressed on the valve seat in a pressing mode, a valve bearing arranged in the valve shell and used for supporting a crankshaft, a motor driving the crankshaft to operate, two output holes A and B connected to suction pipes of sliding vane cavities A and B or two cylinders A and B, a crankshaft in the valve is connected with a valve rotor in the motor, and a valve stator driving the rotor to rotate forwards and backwards in the motor is arranged outside the valve shell. The invention has the advantages of small starting power, low noise, stable operation, good energy-saving effect and good human body comfort.

Description

Variable capacity type rotary compressor and control method thereof

Technical Field

The present invention relates to a variable capacity type rotary compressor and a control method thereof, and more particularly, to a variable capacity type rotary compressor for an air conditioning system and a control method thereof.

Background

At present, the variable frequency compressor can change the total displacement of cylinders by changing the rotating speed of the compressor, and the rotary compressor with double cylinders has extremely strong advantages in the aspect of changing the total displacement of the cylinders through capacity control. Compared with the compressor adopting the frequency conversion technology, the capacity control compressor of the same specification has the characteristics of higher efficiency, lower manufacturing cost, simpler system control, wider application range and more reliable performance.

The common double-cylinder rotary compressor adopts two cylinders with the same displacement, when the compressor works, one cylinder keeps a compressed working state all the time, the other cylinder can work or not, and the external working capacity of the whole compressor is switched in two stages between 100 percent and 50 percent. However, when the working capacity of the rotary compressor with the double cylinders is converted, the change range is large, and the energy saving performance and the comfort of human bodies are poor.

Disclosure of Invention

The invention aims to solve the technical problem of providing a three-section capacity-switching variable-capacity rotary compressor with simple and reasonable structure, low manufacturing cost, good energy-saving effect and good human body comfort and a control method thereof, so as to overcome the defects in the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows: a variable-capacity rotary compressor is composed of two cylinders A and B in the casing of compressor, piston and slide plate in each cylinder, partition between cylinders, eccentric crankshaft for driving piston, and upper and lower bearings for supporting crankshaft.

The control valve device comprises a valve seat arranged in a valve shell, a sliding block pressed on the valve seat in a pressing mode, a valve bearing arranged in the valve shell and used for supporting a crankshaft, a motor for driving the crankshaft to operate, two output holes A and B connected with a sliding sheet cavity A and B or two air cylinders A and B suction pipes, a valve rotor in the motor, and a valve stator in the motor for driving the rotor to rotate positively and negatively, wherein the sliding block is connected with the crankshaft; the side surface of the valve shell is provided with a high-pressure pipe, one end of the high-pressure pipe is communicated with a high-pressure chamber in the valve shell, and the other end of the high-pressure pipe is communicated with a high-pressure chamber of the compressor; the upper bearing, the lower bearing, the clapboard and the two cylinders A and B respectively enclose a sliding vane cavity A and a sliding vane cavity B.

One end of the output pipe A is communicated with the output hole A, the other end of the output pipe A is communicated with the sliding sheet cavity A, one end of the output pipe B is communicated with the output hole B, and the other end of the output pipe B is communicated with the sliding sheet cavity B; the output holes A and B are arranged on the valve seat at an angle of 60-120 degrees along the circumferential direction, and the through holes E and F are arranged on the sliding block at an angle of 60-120 degrees along the circumferential direction; the output holes A and B are arranged on the valve seat along the circumferential direction, and the sliding block is provided with two through holes E and F corresponding to the output holes A and B respectively along the circumferential direction; the center of the sliding block is provided with a long round hole, and when the sliding block rotates, the length of the long round hole meets the requirement that the long round hole is communicated with any one of the output holes A or B.

The control valve device also comprises a first input hole C which is arranged at the center of the first valve seat and communicated with the low-pressure side chamber of the compressor; a first long circular hole communicated with the first input hole C is formed in the center of the first sliding block, and when the first sliding block rotates, the length of the first long circular hole is enough to enable the first long circular hole to be communicated with the first input hole C to any one of the first output holes A or B; one end of the first high-pressure pipe is communicated with a high-pressure chamber of the compressor or the system, and the other end of the first high-pressure pipe is communicated with a high-pressure side chamber of the valve shell.

The above-mentioned control valve device also includes a second inlet hole C, which is set in the center of the second valve seat and communicated with the low-pressure side chamber of the compressor; a second long circular hole communicated with the second input hole C is formed in the center of the second sliding block, and when the second sliding block rotates, the length of the second long circular hole is enough to enable the second long circular hole to be communicated with the second input hole C to any one of the second output holes A or B; one end of the second high-pressure pipe is communicated with the high-pressure side cavity of the compressor, and the other end of the second high-pressure pipe is communicated with the high-pressure side cavity of the valve shell; the second crankshaft is connected with the second valve bearing through threads, the top end of the second crankshaft is connected with the valve rotor, and the bottom end of the second crankshaft is connected with a second input hole C arranged on the second valve seat after penetrating through the second valve bearing and a second long circular hole in the second sliding block; the bottom end of the second crankshaft is of an inverted cone structure, and a second input hole C matched with the second crankshaft is also of an inverted cone structure; one end of the second high-pressure pipe is communicated with the high-pressure side cavity of the compressor or the system, and the other end of the second high-pressure pipe is communicated with the high-pressure side cavity of the valve shell.

The control valve device also comprises a third long circular hole arranged at the center of the third sliding block, and when the third sliding block rotates, the length of the third long circular hole is satisfied that the third long circular hole is communicated with any one of the third output holes A or B; the third sliding block is of an inverted T-shaped structure, the top of the third sliding block is connected with a third crankshaft, a middle rod-shaped part of the third sliding block is provided with a vent hole, a third valve bearing is arranged at the part, close to the center, of the valve housing and is sleeved with the middle rod-shaped part of the third sliding block, an upper cavity is defined between the upper part of the third valve bearing and the inner wall of the valve housing, a communication hole is formed in the part, located in the upper cavity, of the upper end of the vent hole, and a third high-pressure pipe is arranged on; a lower cavity is enclosed between the lower part of the third valve bearing and the inner wall of the valve shell, a third input pipe is arranged on the side surface of the lower cavity, and the third input pipe is communicated with a compressor or a system low pressure; one end of the output pipe A is communicated with the output hole A, the other end of the output pipe A is communicated with the suction pipe of the cylinder A, one end of the output pipe B is communicated with the output hole B, and the other end of the output pipe B is communicated with the suction pipe of the cylinder B; the third output holes A and B are arranged on the third valve seat along the circumferential direction, and the third sliding block is provided with two third through holes E and F corresponding to the output holes A and B along the circumferential direction.

The control valve device comprises a cylindrical cylinder arranged at the lower part of a valve shell, a fourth sliding block is arranged in the cylinder, the fourth sliding block is connected with a fourth crankshaft, the upper part of the fourth crankshaft is provided with threads, and a fourth output pipe A, a fourth output pipe B and a fourth input pipe are arranged on the side surface of the cylinder; the fourth output pipe A and the fourth output pipe B are respectively connected with a sliding vane cavity of a cylinder A and a sliding vane cavity of a cylinder B of the compressor, in addition, the fourth input pipe is connected with a suction pipe of the compressor, and a fourth high-pressure pipe arranged on a valve shell is communicated with a high-pressure cavity of the compressor; the fourth slide block is divided into an upper layer and a lower layer, the fourth crankshaft is connected with the whole fourth slide block in series, the cylindrical cylinder and the upper and lower layers of slide blocks respectively enclose an upper cavity, a middle cavity and a lower cavity, a channel communicated with the upper cavity and the lower cavity is arranged in the fourth crankshaft, the upper cavity and the lower cavity are both high-pressure cavities, the middle cavity is a low-pressure cavity, the fourth output pipe A and the fourth output pipe B are respectively communicated with the upper cavity and the lower cavity, and the fourth input pipe is communicated with the middle low-pressure cavity.

The cylinders A and B have different displacement, the back of the cylinder sliding sheet with small displacement is provided with a spring for pressing the sliding sheet on the piston side, and the back of the cylinder sliding sheet with large displacement is not provided with a spring.

A control method of a capacity-alternating rotary compressor is characterized in that a control valve device realizes three pressure switching through three steps of actions of a sliding block and finally outputs the three pressure switching to a sliding vane cavity or a cylinder of the compressor to realize three-section capacity conversion control: when the pressure switching mode is adopted, two output holes of the control valve device are respectively communicated with the sliding vane cavities of the compressor cylinders A and B, and a first input hole of the control valve device is communicated with the low-pressure side pressure of the compressor or the system, a second input hole of the control valve device is communicated with the high-pressure side of the compressor or the system, wherein the internal pressure of the shell of the compressor is taken as the high-pressure side of the system; the control valve device drives the three-step action of the sliding block arranged on the control valve device through a motor, so that the pressure of the two output holes is switched back and forth between three modes of a high-pressure side, a low-pressure side and a low-pressure side, as well as the low-pressure side and the high-pressure side, and the three-section type capacity conversion control of the compressor is realized; or when the cylinder pressure switching mode is adopted, the two output holes of the control valve device are respectively communicated with the suction pipes of the compressor cylinders A and B, the first input hole of the control valve device is communicated with the high-pressure side pressure of the compressor or the system, and the second input hole of the control valve device is communicated with the low-pressure side pressure of the compressor or the system, the control valve device drives the three-step action of the slide block arranged on the control valve device through the motor, so that the pressures of the two output holes are respectively switched back and forth between the three modes of the low-pressure side and the low-pressure side, the low-pressure side and the high-pressure side, and the high-pressure side and the low-pressure side, and the three; wherein the two cylinders A and B have different displacement sizes.

When the pressure switching mode is adopted, the control valve device drives the slider arranged on the control valve device to act in three steps through the motor, the first input hole is communicated with any one of the two output holes, or the first input hole is not communicated with the second output hole, the second input hole is communicated with the two output holes, or the second input hole is communicated with any one of the two output holes, so that the pressures of the two output holes are respectively switched back and forth between three modes of a high pressure side, a low pressure side and a high pressure side, and the three-section capacity switching control of the compressor is realized; or, when the cylinder pressure switching mode is adopted, the control valve device is communicated with the first input hole and the two output holes or any one of the two output holes through three steps of actions of driving a sliding block arranged on the control valve device by a motor; and the second input hole and any one of the two output holes are communicated at the same time or are not communicated, so that the pressures of the two output holes are switched back and forth between three modes of a low pressure side and a low pressure side, a low pressure side and a high pressure side, and a high pressure side and a low pressure side respectively, and the three-section capacity conversion control of the compressor is realized.

The three modes in the three-stage capacity conversion control can be alternately switched back and forth in sequence, or any mode in the middle can be removed, and only the rest two modes are directly switched back and forth.

The capacity of the capacitor required for operation of the motor of the above-mentioned capacity-sharing rotary compressor adopts two kinds of sizes of Rc2 and Rc3, wherein Rc3 < Rc2, if the compressor of three-stage capacity control is divided into three types according to the operating capacity, the minimum operating capacity mode corresponds to the capacitor Rc3 with smaller capacity, the larger operating capacity mode corresponds to the capacitor Rc2 with larger capacity, and the maximum operating capacity mode corresponds to the superposition of the capacitor with smaller capacity and the capacitor with larger capacity Rc3+ Rc 2; or the capacity of the motor run capacitor is switched without changing the capacity mode of the compressor.

The invention adopts three-step control to enable the pressure in the slide sheet cavity or control the pressure of the cylinder to be independently switched between high pressure and low pressure, wherein, the basic key of the three steps is that two output holes for pressure switching and one input hole for low pressure or high pressure are arranged on the slide block,

when the sliding vane cavity pressure switching mode is used, the two output hole pressures are switched between the high pressure side and the high pressure side, the high pressure side and the low pressure side, and the low pressure side and the high pressure side.

When the cylinder pressure switching manner is used, the two outlet port pressures are switched between the low pressure side and the low pressure side, the low pressure side and the high pressure side, and the high pressure side and the low pressure side.

When the compressor or the system is in operation, the refrigerating capacity can be steplessly adjusted in unit time by controlling the change of the working time in each mode.

The invention has the advantages of small starting power, low noise, stable operation, good energy-saving effect and good human body comfort.

Drawings

Fig. 1 is a schematic structural diagram according to an embodiment of the present invention.

FIG. 2 is a schematic view of a compressor and a control valve with a sliding vane pressure switching mode, partially cut away and enlarged.

Fig. 3-5 are schematic views of the cross-sectional views X-X in fig. 2 showing three enlarged operating states.

FIG. 6 is an enlarged cross-sectional structural schematic view of the control valve at low reversing torque.

Fig. 7 is a schematic view of the cross-section Y-Y in fig. 6.

Fig. 8 is a partial sectional enlarged structural view of a compressor and a control valve of a cylinder pressure switching system.

Fig. 9 is a schematic view of the cross-sectional structure Z-Z in fig. 8.

FIG. 10 is a partial operation circuit diagram of a compressor

Fig. 11-13 are schematic sectional enlarged structural views of a piston control valve with a sliding vane chamber pressure switching mode.

Detailed Description

The invention is further described with reference to the following figures and examples.

In the figure, 1 is a rotary compressor, 2 is a high pressure outlet pipe, 3 is a condenser, 4 is an expansion valve, 5 is an evaporator, 6 is a reservoir, 7 is a control valve, 10 is a cylinder A, 11 is a cylinder B, 12 is a partition plate, 13 is an upper bearing, 14 is a lower bearing, 15 is a sliding vane cavity A, 16 is a sliding vane cavity B, 17 is a spring, 21 is a cylindrical shell,

22 is a first valve seat, 22' is a second valve seat, 22 "is a third valve seat,

23 is a first slide, 23 'is a second slide, 23 "is a third slide, 23'" is a fourth slide,

23.1 is a first through hole F, 23.1 'is a second through hole F, 23.1' is a third through hole F,

23.2 is a first through hole E, 23.2 'is a second through hole E, 23.2' is a third through hole E,

24 is a first crankshaft, 24 'is a second crankshaft, 24 "is a third crankshaft, 24'" is a fourth crankshaft,

25 is a first valve bearing, 25' is a second valve bearing, 42 is a third valve bearing,

26 is a valve rotor, 27 is a valve stator,

output line A at 28, output line A at 28' ″ is the fourth output line A,

output tube B at 29, fourth output tube B at 29' ″,

30 is a first high-pressure pipe, 30 'is a second high-pressure pipe, 30 "is a third high-pressure pipe, 30'" is a fourth high-pressure pipe,

31 is an input pipe, 31' ″ is a fourth input pipe,

32 is a first slotted hole, 32 'is a second slotted hole, 32' is a third slotted hole,

33 is a first output aperture A, 33 ' is a second output aperture A, 33 ' is a third output aperture A, 33 ' is a fourth output aperture A,

34 is a first output aperture B, 34 'is a second output aperture B, 34 "is a third output aperture B, 34'" is a fourth output aperture B,

35 for the first input aperture C, 35 'for the second input aperture C, 35' ″ for the fourth input aperture C,

37 is a vent hole, 38 is an upper chamber, 39 is a lower chamber, 40 is a suction pipe a, 41 is a suction pipe B, 43 is a third inlet pipe C, 45 is a communication hole,

50 is a cylindrical cylinder, 51 is a channel, 52 is an upper cavity, and 53 is a lower cavity.

Referring to fig. 1, a refrigeration cycle system of the variable displacement rotary compressor mounted in a cooling and heating air conditioner will be described. The compressor 1 sucks low-pressure gas from the accumulator, compresses the gas, and discharges high-pressure gas from the high-pressure discharge pipe 2. Then, the liquid refrigerant condensed by the condenser 3 is depressurized by the expansion valve 4, evaporated by the evaporator 5, changed into a low-pressure refrigerant, returned to the accumulator 6, sucked by the compressor again, and compressed. Here, the control valve device 7 is installed outside the compressor, and functions to make the variable capacity type rotary compressor having two cylinders operate, and the independent cylinders continue to be operated for compression or stop operation, so that the refrigerating capacity is switched to three stages in the operation of the compressor. Thus, the two cylinder displacements are different.

For example, in the refrigeration operation of the air conditioner, when rapid refrigeration is required, such as in hot weather in midsummer, when the compressor is required to exert the highest refrigeration capacity, the air conditioner operates according to the maximum mode; when the room temperature is reduced to be close to the target temperature, the operation of the compressor is switched to intermediate capacity, the compressor is operated according to an intermediate mode, and the refrigerating capacity is reduced; when the room temperature further reaches the target temperature, the operation needs to be switched to the low refrigeration capacity operation, and the operation is carried out according to the minimum mode. Therefore, the refrigerating capacity is switched at any time according to the refrigerating load, so that comfortable air conditioning can be performed, the waste of the refrigerating capacity can be prevented, and the efficiency of the air conditioner is improved.

In other words, the capacity variable type rotary compressor, that is, the rotary compressor with capacity control has the same capacity control function as the rotary compressor using the inverter.

The method for switching the control capability of the dual-cylinder rotary compressor will be described as follows, i.e. a "sliding vane chamber pressure switching mode" and a "cylinder pressure switching mode".

The following first describes the vane chamber pressure switching mode, and then the cylinder pressure switching mode.

Sliding vane cavity pressure switching mode

When the work and stop of the cylinder are controlled by the pressure switching mode of the sliding vane cavity, the pressure switching of the sliding vane cavity between high pressure and low pressure needs to be sealed at first. If the vane chamber is on the high pressure side, as in a conventional rotary compressor, the vanes compress the outer circumferential surface of the piston. However, if the vane cavity is on the low pressure side, the vane does not slide out of the vane cavity without a compression effect. In this case, the piston rotates but does not compress, and idles.

Referring to fig. 2 to 5, the twin-cylinder rotary compressor is provided with two cylinders a10 and B11, whose vane chambers (i.e., the cavity portions of the back of the vanes) are sealed by a partition plate 12, and upper and

lower bearings

13 and 14 in the cylinders, which constitute a vane chamber a15 and a vane chamber B16. Wherein, the cylinder sliding vane cavity B with small displacement is provided with a spring 17 pressing the sliding vane on the piston side, the control valve device 7 attached outside the shell of the compressor comprises a first valve seat 22 arranged in the valve shell 21, a first sliding block 23 pressed on the first valve seat 22, the first sliding block 23 connected with a first crankshaft 24, a first valve bearing 25 arranged in the valve shell 21 for supporting the first crankshaft 24, a motor for driving the first crankshaft 24 to run, the first crankshaft 24 connected with a valve rotor 26 in the motor, and a valve stator 27 driving the rotor to rotate positively and negatively arranged outside the valve shell 21; the motor is a stepping motor, and can detect the rotation angle of the valve rotor. The first valve seat 22 is provided with a first output hole A33 and a first output hole B34 which are connected with a sliding vane cavity A15 and a sliding vane cavity B16, and the first output holes A33 and B34 are arranged on the first valve seat 22 along the circumferential direction at an angle of 60-120 degrees; the first through holes E23.2 and F23.1 are arranged on the first sliding block 23 along the circumferential direction at an angle of 60-120 degrees, and the first through holes E23.2 and F23.1 correspond to the first output holes A and B respectively; the side surface of the valve shell 21 is provided with a first high-pressure pipe 30, one end of which is communicated with a high-pressure chamber in the valve shell 21, and the other end of which is communicated with the high-pressure chamber of the compressor; the control valve means further comprises a first inlet hole C35, placed in the centre of the first seat 22, communicating with the chamber on the low pressure side of the compressor; the first slider 23 is provided at the center with a first oblong hole 32 communicating with the first input hole C35, wherein the first oblong hole 32 has a length sufficient to communicate the first input hole C35 to any one of the first output holes a33 or B34. One end of the output pipe A28 is communicated with the first output hole A33, the other end is communicated with the slide sheet cavity A15, one end of the output pipe B29 is communicated with the first output hole B34, and the other end is communicated with the slide sheet cavity B16. The inside of the cylindrical housing 21 is a high pressure side, the input pipe 31 is connected to a low pressure side such as a suction pipe, and the first input hole C35 is a low pressure side.

The first oblong hole 32 of the first slider 23 is sealed, and since the first input hole C35 is a low pressure side, the pressure of the first oblong hole is low.

The first slider 23 rotates at an interval of 60 to 120 degrees by a stepping motor, and 120 degrees is selected in the embodiment.

When the control valve is in the maximum mode, see fig. 3, the first oblong hole 32 has a rotation angle of 0 °. That is, the first oblong hole 32 is 120 ° apart from the first output hole a33 and the first output hole B34, respectively, and therefore does not communicate with the first output hole a33 or the first output hole B34. However, since the first output holes a33 and B34 are aligned with the first through holes E23.2 and F23.1 of the first slider, the two holes are opened, and the pressure of the first output holes a and B is the same as the internal pressure of the cylindrical case 21, and is on the high pressure side.

When the first slider 23 rotates 120 ° clockwise, the intermediate mode is entered, see fig. 4, the first oblong hole 32 communicates with the first output hole B34, and the first output hole B34 is on the low pressure side. On the other hand, since the first output port a33 is open, the first output port a33 is on the high pressure side.

The minimum mode is entered when the first slider 23 is rotated further 120 deg. in the clockwise direction. At this time, the first oblong hole 32 communicates with the first output hole a33, and the first output hole a33 is on the low pressure side. On the other hand, the first output hole B34 is in an open state, and the first output hole B34 is on the high pressure side.

When the first oblong hole 32 of the first slider 23 is in the maximum mode and is in a position not communicating with the first output hole a33 or B34, the output pipe a28 and the output pipe B29 are on the high pressure side, and the vane chamber a and the vane chamber B are on the high pressure side. The cylinders A and B are provided with sliding sheets which slide out and are switched into a normal compression working state.

When the first oblong hole 32 of the first slider 23 is in the neutral mode, the first slider 23 is in a position in which it communicates with the first output hole B34, and the output pipe B29 is on the low pressure side, but the output pipe a28 is on the high pressure side, so that the vane chamber a is on the high pressure side and the vane chamber B is on the low pressure side. Therefore, the cylinder A slides out to be in a normal compression working state. However, the vane of the cylinder B cannot slide out, and is accommodated in the vane chamber without being compressed.

When the first oblong hole 32 of the first slider 23 is in the minimum mode, it is in a position of communication with the first output hole a33, the output pipe B29 is on the high pressure side, the output pipe a28 is on the low pressure side, the cylinder a is in the non-operating state, and the cylinder B is in the operating state.

For the switch combination of the double cylinders, three kinds of capacity control can be carried out. In addition, as described above, the modes can be switched in the order of 1, 2 and 3 by rotating the sliders by 120 degrees, respectively,

if the reciprocating switching between the maximum mode and the middle mode is required, namely the reciprocating switching operation from the maximum mode to the middle mode is carried out, the sliding block is firstly rotated by 120 degrees clockwise from the maximum mode to the middle mode and then rotated by 240 degrees back to the maximum mode. In cycles, the maximum mode and the intermediate mode may be repeated, such that the slider is rotated 240 ° in order to omit the intermediate unwanted minimum mode. This is a very important function in actual system control.

Referring to fig. 6-7, the second oblong hole 32 ' of the second slider 23 ' is a low pressure side, but the exterior of the second slider 23 ' is a high pressure side. Therefore, the second slider 23 'is pressed above the second valve seat 22', and a thrust force is generated. When the torque of the stepping motor is sufficiently large, the second slider 23 'can be rotated against the thrust force, but when the torque is small, the second slider 23' cannot be driven to rotate. If the internal and external pressures of the second slider 23 'can be balanced, the second slider 23' can be driven to rotate under the condition of small moment.

The second crankshaft 24 ' is connected with the second valve bearing 25 ' through a screw thread, the top end of the second crankshaft is connected with the valve rotor 26, and the bottom end of the second crankshaft is connected with a second input hole C35 ' arranged on the second valve seat 22 ' after passing through the second valve bearing 25 ' and a second long round hole 32 ' on the second slider 23 '; the bottom end of the second crankshaft 24 'is in a reverse tapered structure, and the second input hole C35' matched with the bottom end of the second crankshaft is also in a reverse tapered structure. Since the second crankshaft 24 'is screw-coupled to the second valve bearing 25', the second input hole C35 'can be opened or closed while the second crankshaft 24' moves up and down when the valve rotor 26 rotates.

The second inlet hole C35' is often open when the compressor is running. When the compressor switches the mode during operation, the second input hole C35 'is closed by the second crankshaft 24' rotating to the right. Therefore, the internal pressure of the second slider 23 'is high regardless of the position of the second slider 23' in the maximum mode, the middle mode, or the minimum mode; that is, since the volume of the space of the second slider 23 ' is small, the gas sealing of the surface of the second valve seat 22 ' is not sufficiently tight, and the second slider 23 ' does not generate a thrust even when the internal pressure of the second slider 23 ' is on the high pressure side, the second slider 23 ' can be freely rotated with a small moment.

When the second slider 23 'is rotated to a predetermined position, the second crankshaft 24' is rotated leftward to open the second input hole C35 ', so that the second oblong hole 32' of the second slider 23 'is a low pressure side, and a stopping force is generated to the second slider 23' again, so that the second slider 23 'is fixed to the second valve seat 22' again. The mode switching is thus completed.

When one cylinder of the double-cylinder rotary compressor starts to compress, the shell pressure starts to rise, and the slide sheet of the other cylinder slides out simultaneously to compress. Thus, the spring in one of the cylinders may be omitted.

If a spring is arranged in the cylinder with small displacement, the compression at the starting is started from the cylinder with small displacement, the starting load is small, and the advantages of reducing the motor torque and reducing the vibration of the compressor are achieved.

For the same reasons as described above, it is recommended that the compressor be stopped by switching to a cylinder having a smaller displacement and then stopping the compressor. If the minimum mode is a state as a minimum capacity, the minimum mode is used for stopping, and the vibration generated when the compressor is stopped can be minimized.

Referring to fig. 8, the cylinder pressure switching manner is a method of switching the pressure of a suction pipe connected to a cylinder inlet between a low pressure and a high pressure. If the pressure is low, normal compression is possible, but if the pressure is high, the vane and the piston cannot be pressed and are accommodated in the vane chamber. That is, the piston is idle, but can rotate, and is not compressed.

The third slide block 23 'is in an inverted T-shaped structure, the top of the third slide block is connected with the third crankshaft 24', the rod-shaped part in the middle of the third slide block is provided with a vent hole 37, the lower end of the vent hole 37 is provided with a third input hole C35 ', the part of the valve housing 21 near the center is provided with a third valve bearing 42 which is sleeved with the rod-shaped part in the middle of the third slide block 23', an upper chamber 38 is enclosed between the upper part of the third valve bearing 42 and the inner wall of the valve housing 21, the part of the upper end of the vent hole 37, which is positioned in the upper chamber 38, is provided with a communicating; a lower chamber 39 is defined between the lower part of the third valve bearing 42 and the inner wall of the valve housing 21, a third input pipe 43 is arranged on the side surface of the lower chamber 39, and the third input pipe 43 is communicated with an outlet of the liquid reservoir 6. The communication hole 45 and the third input hole 35 "are on the high pressure side; the lower chamber 39 being the low pressure side

The third slider 23 "will rotate at 120 deg. intervals in a clockwise direction as shown in fig. 3-5. The method of three-stage capacity control by the cylinder pressure switching method is basically the same as the sliding vane chamber pressure switching method, but the difference is that the pressures of the output port and the input port are opposite.

If the minimum cooling capacity is the minimum mode, then it is easy to know that decreasing the displacement of cylinder B will result in a decrease in the minimum cooling capacity of the entire compressor. However, given the total displacement of cylinders A + B, if the displacement of cylinder B is reduced alone, the displacement of cylinder A will increase, with less capacity difference between the maximum and intermediate modes; on the other hand, the difference in the capacity between the intermediate mode and the minimum mode becomes large. The variable range of capacity that can be achieved by the compressor can be broadened if the minimum cooling capacity is minimized, but the balance of capacity differences between the modes is worsened, with the immediate drawback that the effect of the three-stage capacity control is generally diminished.

The following shows the relationship between minimum mode operation (at minimum capacity) and COP (which is the energy efficiency ratio of the compressor, i.e. the ratio of the cooling capacity of the compressor to the input electric power) when the total displacement of the cylinders a + B is constant and the displacement of the cylinder B is varied. Here, the experimental results and the simulation results show that the seasonal energy consumption is the best when Vd is 1, Vd1 is 0.6 to 0.7, and Vd2 is 0.4 to 0.3, where Vd is equal to the displacement of the cylinder a (Vd1) + the displacement of the cylinder B (Vd 2). For example, if the displacement of cylinder A is 7.0cc and the displacement of cylinder B is 3.0cc, then when cylinders A and B are compressed (maximum mode), the displacement is 10cc, operating at 100% capacity; only compression cylinder a (mid mode), 7.0cc displacement, run at 70% capacity; only compression cylinder B (minimum mode), displacement 3.0cc, was operated at 30% capacity.

Referring to fig. 10, in the rotary compressor, in order to increase torque of a motor of the compressor and increase efficiency, a run capacitor RC is generally used, but it is required to optimize a capacity of the capacitor according to a running load of the compressor. Therefore, in the three-stage capacity control rotary compressor, it is also necessary to select an optimum capacitor capacity according to each mode. In the figure, a method of selecting a capacitor capacity for improving efficiency when controlling cost increase is shown, that is, Rc3 is selected in a minimum mode with the smallest operating load, Rc2 is selected in an intermediate mode with a smaller operating load, and Rc2+ Rc3 is selected in a maximum mode with the largest load, so that the capacitor capacity is expanded.

However, if the outdoor temperature is very high during the cooling operation of the air conditioner, the operation load is greater than the compressor capacity, or the voltage is abnormally low. In such abnormal situations, the maximum mode operation may not be continued, but only the intermediate mode operation may be switched. However, when the motor torque is insufficient in the middle mode operation, the capacity of the operation capacitor can be selected to be the same as that of the maximum mode, and the capacity of the operation capacitor can be selected to be Rc2+ Rc3, so that the motor torque insufficiency can be compensated.

In contrast, when the operation load of the compressor is small in the maximum mode or the middle mode operation, the middle mode, the minimum mode run capacitor, may be used to improve the motor efficiency, respectively. In order to improve the efficiency of the compressor and the motor, at least two kinds of operation capacitors should be prepared and an optimal operation capacitor combination should be selected.

The lower panel shows the stepless adjustment of capacity by varying the operating time in each mode within a segment to vary the compressor or system. Setting the cold quantity per unit time of the cylinder A + the cylinder B as Q' and the cold quantity per unit time of the cylinder A as Qa; the cooling capacity of the cylinder B in unit time is Qb; during the running time T, the running time in the cylinder A + cylinder B mode is T'; the operation time in the cylinder A mode is Ta; the operation time of the cylinder B operation mode is Tb; the refrigeration capacity of the compressor during time T is then: q '× T' + Qa × Ta + Qb × Tb; the compressor has shutdown time within the time T, so that T is more than or equal to T' + Ta + Tb; because the cold quantity of the compressor or the system in each mode is different, the cold quantity of the compressor is infinitely adjusted from the minimum 0 to the maximum Q' × T by changing the composition proportion of the running time in the unit time in each mode and combining the stop of the compressor.

Referring to fig. 11-13, the aforementioned slider operation is rotational, and the slider reciprocating operation will be briefly described. The control valve device comprises a cylindrical cylinder 50 arranged at the lower part of a valve shell 21, a fourth slide block 23 ' is arranged in the cylinder, the fourth slide block 23 ' is connected with a fourth crankshaft 24 ', the upper part of the fourth crankshaft 24 ' is provided with threads, and a fourth output pipe A28 ', a fourth output pipe B29 ' and a fourth input pipe 31 ' are arranged at the side surface of the compressor cylinder; a fourth high pressure tube 30'; a fourth output pipe a28 '″ and a fourth output pipe B29' ″ are respectively connected to sliding vane chambers of cylinders a and B of the compressor, and in addition, the fourth input pipe 31 '″ is connected to a compressor suction pipe, and the fourth high pressure pipe 30' ″ is communicated with a high pressure chamber of the compressor; the fourth slider 23 ' is divided into an upper layer and a lower layer, the fourth crankshaft 24 ' is connected with the whole slider in series, the cylindrical cylinder 50 and the sliders in the upper layer and the lower layer respectively enclose an upper cavity, a middle cavity and a lower cavity, a channel 51 for communicating the upper cavity 52 with the lower cavity 53 is arranged in the fourth crankshaft 24 ', and the upper cavity and the lower cavity are both high-pressure chambers, namely high-pressure sides Pd; the middle cavity is a low pressure chamber, i.e., the low pressure side Ps, and the fourth outlet pipe a28 '"and the fourth outlet pipe B29'" are respectively communicated with the upper and lower high pressure cavities, and the fourth inlet pipe is communicated with the middle low pressure cavity. The fourth slider 23' ″ has a disc shape at both ends, and has a small clearance from the cylindrical cylinder wall when moving up and down. On the other hand, the upper crankshaft of the fourth slider 23 ' ″ is threaded, and when the valve rotor 26 rotates the fourth crankshaft 24 ' ″, the fourth slider 23 ' ″ can move up and down. The fourth output pipes A28 'and B29' in piston stroke 1, on the low pressure side, are in maximum mode; the fourth output line A28 '"for Stroke 2 is on the high side and the fourth output line B29'" is on the low side, for mid mode; stroke 3 is reversed, with the fourth output tube B29 '"on the high side, but the fourth output tube A28'" on the low side, in the minimum mode.

The above is an example of switching the three-stage mode by switching the pressures of the delivery pipes a28 ' "and B29 '" to three states by reciprocating the circular plate-shaped fourth slider 23 ' "up and down in the cylinder.

Claims

1. A variable-capacity rotary compressor comprises two cylinders A and B (10 and 11) arranged in a compressor shell, wherein a piston and a slide sheet are respectively arranged in the two cylinders, a partition plate (12) is arranged between the cylinders, an eccentric crankshaft for driving the piston and upper and lower bearings (13 and 14) for supporting the crankshaft are also arranged in the compressor shell, and the variable-capacity rotary compressor is characterized in that a control valve device for controlling the capacity conversion of three sections of the compressor is arranged outside the compressor shell.

2. A variable capacity type rotary compressor according to claim 1, wherein the control valve means comprises a valve seat provided in a valve housing (21), and a slider press-fitted on the valve seat, the slider being connected to a crankshaft, a valve bearing provided in the valve housing for supporting the crankshaft, a motor for driving the crankshaft to operate, the valve seat being provided with two output ports a and B connected to suction pipes of vane chambers a and B (15 and 16) or two cylinders a and B (10 and 11), the crankshaft being connected to a valve rotor (26) in the motor, a valve stator (27) for driving the rotor to rotate in forward and reverse directions in the motor being provided outside the valve housing (21); the side surface of the valve shell (21) is provided with a high-pressure pipe, one end of the high-pressure pipe is communicated with a high-pressure chamber in the valve shell (21), and the other end of the high-pressure pipe is communicated with the high-pressure chamber of the compressor; the upper bearing, the lower bearing, the partition plate and the two cylinders A and B respectively enclose sliding vane cavities A and B (15 and 16).

3. A variable capacity rotary compressor according to claim 2, wherein the output pipe a has one end communicating with the output port a and the other end communicating with the vane chamber a (15), and the output pipe B has one end communicating with the output port B and the other end communicating with the vane chamber B (16); the output holes A and B are arranged on the valve seat at an angle of 60-120 degrees along the circumferential direction, and the through holes E and F are arranged on the sliding block at an angle of 60-120 degrees along the circumferential direction; the output holes A and B are arranged on the valve seat along the circumferential direction, and the sliding block is provided with two through holes E and F corresponding to the output holes A and B respectively along the circumferential direction; the center of the sliding block is provided with a long round hole, and when the sliding block rotates, the length of the long round hole meets the requirement that the long round hole is communicated with any one of the output holes A or B.

4. A variable capacity type rotary compressor according to claim 3, wherein said control valve means further comprises a first input hole C (35) provided at the center of the first valve seat (22) and communicating with a chamber on a low pressure side of the compressor; a first long circular hole (32) communicated with the first input hole C (35) is formed in the center of the first sliding block (23), and when the first sliding block rotates, the length of the first long circular hole is enough to communicate the first input hole C with any one of the first output holes A (33) or B (34); one end of the first high-pressure pipe (30) is communicated with the high-pressure side cavity of the compressor, and the other end of the first high-pressure pipe is communicated with the high-pressure side cavity of the valve shell (21).

5. A variable capacity type rotary compressor according to claim 3, wherein said control valve means further comprises a second inlet hole C (35 ') provided at the center of the second valve seat (22') to communicate with a chamber on a low pressure side of the compressor; a second long circular hole (32 ') communicated with the second input hole C (35 ') is formed in the center of the second sliding block (23 '), and when the second sliding block rotates, the length of the second long circular hole is enough to communicate the second input hole C with any one of the second output holes A (33 ') or B (34 '); one end of the second high-pressure pipe (30') is communicated with the high-pressure side cavity of the compressor, and the other end is communicated with the high-pressure side cavity of the valve shell (21); the second crankshaft (24 ') and the second valve bearing (25') are connected through threads, the top end of the second crankshaft is connected with the valve rotor (26), and the bottom end of the second crankshaft is connected with a second input hole C (35 ') arranged on the second valve seat (22') after passing through the second valve bearing and a second long circular hole (32 ') formed in the second sliding block (23'); the bottom end of the second crankshaft is of an inverted cone structure, and a second input hole C matched with the second crankshaft is also of an inverted cone structure; the second high pressure pipe (30') has one end communicating with the high pressure side chamber of the compressor or system and the other end communicating with the high pressure side chamber of the valve housing (21).

6. A variable capacity type rotary compressor according to claim 3, wherein said control valve means further comprises a third elongated hole (32") provided at the center of the third slider (23") and having a length sufficient to communicate with either one of the third output holes a (33") or B (34") when the third slider is rotated; the third sliding block (23 ') is of an inverted T-shaped structure, the top of the third sliding block is connected with a third crankshaft (24'), a middle rod-shaped part of the third sliding block is provided with a vent hole (37), a part of the valve housing (21) close to the center is provided with a third valve bearing (42) which is sleeved with the middle rod-shaped part of the third sliding block, an upper cavity (38) is enclosed between the upper part of the third valve bearing and the inner wall of the valve housing, the part of the upper end of the vent hole, which is located in the upper cavity, is provided with a communication hole (45), and the side surface of the upper cavity is provided with a third; a lower cavity (39) is enclosed between the lower part of the third valve bearing and the inner wall of the valve shell, a third input pipe (43) is arranged on the side surface of the lower cavity, and the third input pipe is communicated with a compressor or a low-pressure outlet of a system; one end of the output pipe A is communicated with the output hole A, the other end of the output pipe A is communicated with the suction pipe of the cylinder A (10), one end of the output pipe B is communicated with the output hole B, and the other end of the output pipe B is communicated with the suction pipe of the cylinder B (111); the third output holes A and B are arranged on the third valve seat along the circumferential direction, and the third sliding block is provided with two third through holes E and F corresponding to the output holes A and B along the circumferential direction.

7. A variable capacity type rotary compressor according to claim 2, wherein the control valve means comprises a cylinder (50) having a cylindrical shape and provided at a lower portion of the valve housing (21), a fourth slider (23 *) provided in the cylinder, the fourth slider being connected to a fourth crankshaft (24 *), an upper portion of the fourth crankshaft being threaded, a side surface of the cylinder being provided with a fourth outlet pipe a (28 *), a fourth outlet pipe B (29 *) and a fourth inlet pipe (31 *); the fourth output pipe A and the fourth output pipe B are respectively connected with sliding vane cavities of cylinders A and B (10 and 11) of the compressor, in addition, the fourth input pipe is connected with a suction pipe of the compressor, and a fourth high-pressure pipe (30 *) arranged on a valve shell is communicated with a high-pressure cavity of the compressor; the fourth sliding block is divided into an upper layer and a lower layer, the fourth crankshaft is connected with the whole fourth sliding block in series, the cylindrical cylinder and the upper and lower layers of sliding blocks respectively enclose an upper cavity, a middle cavity and a lower cavity, a channel (51) for communicating the upper cavity with the lower cavity (52 and 53) is arranged in the fourth crankshaft, the upper cavity and the lower cavity are both high-pressure chambers, the middle cavity is a low-pressure chamber, the fourth output pipe A and the fourth output pipe B are respectively communicated with the upper cavity and the lower cavity, and the fourth input pipe is communicated with the middle low-pressure chamber.

8. A variable capacity type rotary compressor according to claim 1 or 2, wherein the cylinders a and B (10 and 11) have different displacements, and the back of the vane of the cylinder having the small displacement has a spring (17) for pressing the vane to the piston side, and the back of the vane of the cylinder having the large displacement has no spring.

9. A control method of a variable-capacity rotary compressor is characterized in that: the control valve device realizes three kinds of pressure switching through the actions of three steps of the sliding block, and finally outputs the three kinds of pressure switching to a sliding sheet cavity or a cylinder of the compressor to realize three-section type capacity switching control:

when the pressure switching mode is adopted, two output holes of the control valve device are respectively communicated with the sliding vane cavities of the compressor cylinders A and B, and a first input hole of the control valve device is communicated with the low-pressure side pressure of the compressor or the system, a second input hole of the control valve device is communicated with the high-pressure side of the compressor or the system, wherein the internal pressure of the shell of the compressor is taken as the high-pressure side of the system; the control valve device drives the three-step action of the sliding block arranged on the control valve device through a motor, so that the pressure of the two output holes is switched back and forth between three modes of a high-pressure side, a low-pressure side and a low-pressure side, as well as the low-pressure side and the high-pressure side, and the three-section type capacity conversion control of the compressor is realized;

or,

when the cylinder pressure switching mode is adopted, two output holes of the control valve device are respectively communicated with suction pipes of a compressor cylinder A and a compressor cylinder B, a first input hole of the control valve device is communicated with the high-pressure side pressure of the compressor or the system, and a second input hole of the control valve device is communicated with the low-pressure side pressure of the compressor or the system, the control valve device drives a sliding block arranged on the control valve device to act in three steps through a motor, so that the pressures of the two output holes are respectively switched back and forth between three modes of the low-pressure side and the low-pressure side, the low-pressure side and the high-pressure side, and the high-pressure side and the low-pressure side, and the three;

wherein the two cylinders A and B have different displacement sizes.

10. The method as claimed in claim 9, wherein when the sliding vane chamber pressure switching mode is adopted, the control valve device is operated in three steps by driving a slider disposed thereon by a motor to communicate with the first input hole and either one of the two output holes, or neither one of the two output holes, and simultaneously communicate with the second input hole and both of the two output holes, or communicate with the second input hole and either one of the two output holes, so that the pressures of the two output holes are switched back and forth between three modes of a high pressure side and a high pressure side, a high pressure side and a low pressure side, and a low pressure side and a high pressure side, respectively, thereby realizing three-stage capacity switching control of the compressor;

or,

when the cylinder pressure switching mode is adopted, the control valve device drives the sliding block arranged on the control valve device to act in three steps through the motor, and the first input hole and the two output holes or any one of the two output holes are communicated; and the second input hole and any one of the two output holes are communicated at the same time or are not communicated, so that the pressures of the two output holes are switched back and forth between three modes of a low pressure side and a low pressure side, a low pressure side and a high pressure side, and a high pressure side and a low pressure side respectively, and the three-section capacity conversion control of the compressor is realized.

11. The method as claimed in claim 9, wherein three modes of the three-stage capacity switching control are alternately switched back and forth in sequence, or any one of the three modes is eliminated, and the three modes are directly switched back and forth only between the remaining two modes.

12. The method as claimed in claim 9, wherein the capacity of the capacitor required for operation of the motor of the variable capacity type rotary compressor is two kinds of Rc2 and Rc3, wherein Rc3 < Rc2, and if the three-stage capacity controlled compressor is sequentially divided into three according to the operation capacity, the minimum operation capacity mode corresponds to the capacitor Rc3 of smaller capacity, the greater operation capacity mode corresponds to the capacitor Rc2 of larger capacity, and the maximum operation capacity mode corresponds to the superposition Rc3+ Rc2 of the capacitor of smaller capacity and the capacitor of larger capacity; or the capacity of the motor run capacitor is switched without changing the capacity mode of the compressor.

13. The method as set forth in claim 9, wherein the length of time of operation in each mode is arbitrarily controlled, so that the operation time in each mode can be adjusted to realize stepless adjustment of the refrigerating capacity of the compressor or system per unit time.