A screw refrigeration compressor

Abstract

The application discloses a screw refrigeration compressor, which comprises a shell, a first rotor, a second rotor and a communication shaft; the shell is provided with an air inlet and an air outlet; the first rotor and the second rotor are rotatably connected to the interior of the shell and are mutually engaged; the air inlet is communicated with an air inlet cavity formed by the engagement of the first rotor and the second rotor; the air outlet is communicated with an air outlet cavity formed by the engagement of the first rotor and the second rotor; a connecting channel is arranged between the air inlet and the air outlet; and the communication shaft is located in the connecting channel to control the on-off of the connecting channel. The screw refrigeration compressor can realize no-load starting, reduce the starting load and prolong the service life of the motor.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of compressor, and particularly relates to a screw refrigeration compressor. BACKGROUND

[0002] In the field of air conditioning and refrigeration, screw refrigeration compressors are widely used. Screw refrigeration compressor is a kind of refrigeration compressor, which is a high-speed rotary volumetric compressor. The working process of screw compressor relies on the periodic meshing of male and female rotor helical tooth surfaces, so that the male and female rotors continuously rotate to suck in gas, and the gas is accumulated between the rotors and the shell, and is compressed with the rotation of the rotors, and finally is discharged.

[0003] The screw compressor in the prior art has the following problems in use:

[0004] 1. When the screw compressor starts, the rotor rotates unstably, which causes the torque of the screw compressor to be too large in the process of starting, and in severe cases, the motor is overloaded, which shortens the service life of the motor.

[0005] 2. Since the screw compressor compresses gas by rotating the rotor, the rotor is subjected to outward radial force during compression, which increases the wear of the rotor on the bearing and affects the service life of the screw compressor.

[0006] 3. Since the screw compressor generates a large amount of heat during operation, the excessive heat will affect the efficiency of the screw compressor, so a cooler is needed to cool the screw compressor. However, the current cooler is generally placed outside the screw compressor shell, and cannot effectively cool the heat generated by the internal rotor. SUMMARY

[0007] In view of the above problems, the present application provides a screw refrigeration compressor to overcome the above problems or at least partially solve the above problems.

[0008] The screw refrigeration compressor comprises a shell, a first rotor, a second rotor and a communication shaft. The shell is provided with an air inlet and an air outlet. The first rotor and the second rotor are rotatably connected to the inside of the shell and mesh with each other. The air inlet is in communication with an air inlet cavity formed by the meshing of the first rotor and the second rotor. The air outlet is in communication with an air outlet cavity formed by the meshing of the first rotor and the second rotor. A connecting channel is provided between the air inlet and the air outlet, and the communication shaft is located in the connecting channel to control the on-off of the connecting channel.

[0009] Preferably, the screw refrigeration compressor further comprises a first pushing slider and a second pushing slider, an end of the first rotor is provided with a first rotor shaft, and an end of the second rotor is provided with a second rotor shaft; the first pushing slider and the second pushing slider are respectively in sliding connection with the shell, the first pushing slider is located on a side of the first rotor shaft away from the second rotor shaft, and the second pushing slider is located on a side of the second rotor shaft away from the first rotor shaft; the first pushing slider can be moved to be in rotational contact with the first rotor shaft and apply an action force to the first rotor shaft towards the second rotor shaft; and the second pushing slider can be moved to be in rotational contact with the second rotor shaft and apply an action force to the second rotor shaft towards the first rotor shaft.

[0010] Preferably, the screw refrigeration compressor further comprises a control rod, a first connecting rod and a second connecting rod; one end of the control rod is connected with one end of the first connecting rod and one end of the second connecting rod at the same time, the other end of the first connecting rod is connected with the first pushing slider, and the other end of the second connecting rod is connected with the second pushing slider.

[0011] Preferably, the screw refrigeration compressor further comprises a gear pump, the first rotor is provided with a first internal passage penetrating along an axial direction thereof, and the second rotor is provided with a second internal passage penetrating along an axial direction thereof; a pump outlet of the gear pump is in communication with the first internal passage, the first internal passage is in communication with the second internal passage, and the second internal passage is in communication with a liquid outlet.

[0012] Preferably, the screw refrigeration compressor further comprises a control valve; the control valve is located at the pump outlet to control a medium pressure at the pump outlet.

[0013] Preferably, the screw refrigeration compressor further comprises a control spring; the control spring is connected with the control rod to drive the control rod to move the first connecting rod and the second connecting rod, so that the first pushing slider is away from the first rotor shaft and the second pushing slider is away from the second rotor shaft; the pump outlet is in communication with a cavity in which the control rod is located, to output high-pressure medium to drive the control rod to move against the control spring.

[0014] Preferably, the control valve comprises a valve body, a valve core, a valve core spring and a one-way valve; the valve body is provided with a first valve port, a second valve port and a third valve port; the valve core is located between the first valve port and the second valve port, the valve core spring is connected with the valve core to drive the valve core to move relative to the valve body to block the first valve port; the one-way valve is located on the valve core to realize one-way communication between the third valve port and the first valve port; the valve body is rotationally connected on the shell to control the third valve port to communicate with the pump outlet and the first valve port to communicate with the first internal channel, or control the first valve port to communicate with the pump outlet and the second valve port to communicate with the first internal channel.

[0015] Preferably, the screw refrigeration compressor further comprises a control motor, and the communication shaft is provided with a through hole; the control motor is connected with the communication shaft to drive the communication shaft to reciprocating rotate relative to the shell and control the through hole to be connected with or disconnected from the connection channel.

[0016] Preferably, the screw refrigeration compressor further comprises a driving rod, a driving gear and a transmission gear; one end of the driving rod is eccentrically rotationally connected with an end surface of the communication shaft, the other end of the driving rod is eccentrically rotationally connected with an end surface of the driving gear, the driving gear is rotationally connected on the shell and is meshingly connected with the transmission gear, and the transmission gear is coaxially sleeved and fixed on an end portion of the valve body.

[0017] Preferably, the gear pump comprises a first gear and a second gear which are meshingly connected; the first gear is sleeved and fixed on the first rotor shaft and / or the second gear is sleeved and fixed on the second rotor shaft, the inlet is connected with a liquid inlet cavity formed by the first gear and the second gear in communication, and the pump outlet is connected with a liquid outlet cavity formed by the first gear and the second gear in communication.

[0018] The screw refrigeration compressor has the following beneficial technical effects:

[0019] 1. In the present application, by arranging the communication shaft between the gas inlet and the gas outlet, the communication shaft is used to control the connection channel between the gas inlet and the gas outlet to be connected or disconnected, so that when the screw refrigeration compressor is just started, the communication shaft is controlled to connect the gas inlet and the gas outlet, so that the screw compressor will not be started under load, the load during starting is reduced, the service life of the driving motor is prolonged, and after the first rotor and the second rotor rotate stably, the communication shaft is controlled to disconnect the gas inlet and the gas outlet, so that the screw refrigeration compressor works normally.

[0020] 2. In the present invention, a gear pump is provided on the rotor shaft and an internal channel is provided inside the rotor to make the rotor rotate. When the screw compressor is working, the rotation of the gear pump draws in and pumps out the cooling medium, so that the cooling medium passes through the internal channel of the rotor and directly takes away the heat generated when the rotor is working, thereby achieving a better cooling effect.

[0021] 3. In the present invention, by providing a control rod and a push slider, the control rod can be pushed by the pressure cooling medium to drive the push slider to move toward the middle, thereby applying a thrust toward the middle to the rotor shaft to balance the outward thrust of the gas on the two rotors when they are working, thereby reducing bearing wear, making the rotor rotation more stable, and improving efficiency.

[0022] 4. In the present invention, by setting a control valve, when the screw refrigeration compressor is just started, the gear pump pumps out the cooling medium, so that the cooling medium flows out through the one-way valve in the control valve, that is, the cooling medium flows without pressure, allowing the rotor to rotate without load. When the screw refrigeration compressor is working normally, the control valve rotates 180 degrees, so that the cooling medium pumped out by the gear pump passes through the valve core in the control valve, so that the cooling medium is pressurized, and then the control rod drives the slider to apply radial force to the rotor shaft, which is simple to control.

[0023] 5. In the present invention, through the cooperation of the connecting rod, the driving gear and the transmission gear, when the screw refrigeration compressor is just started, the connecting shaft is in a state where the air inlet and the air outlet are connected, and the control valve is in a no-load state. When the screw refrigeration compressor is working normally, the connecting shaft is driven to rotate by the driving motor to close the air inlet and the air outlet. At the same time, the driving gear is driven to rotate by the connecting rod, and then the control valve is driven to rotate by the transmission gear, so that the control valve is in a loaded state, so that the screw refrigeration compressor can work normally. In this way, control can be completed by a driving motor, and the control is simple and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the cross-sectional structure of the screw refrigeration compressor of this embodiment;

[0025] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure in the AA direction;

[0026] Figure 3 for Figure 1 Schematic diagram of the incomplete cross-section structure in the middle BB direction;

[0027] Figure 4 for Figure 1 Schematic diagram of the cross-sectional structure in the middle BB direction;

[0028] Figure 5 forFigure 4 schematic diagram of the cross-sectional structure in the direction of C-C;

[0029] Figure 6 schematic diagram of the cross-sectional structure in the direction of C-C; Figure 4 schematic diagram of the cross-sectional structure in the direction of D-D;

[0030] Figure 7 schematic diagram of the cross-sectional structure in the direction of D-D; Figure 4 schematic diagram of the cross-sectional structure in the direction of E-E, F-F. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be further described in detail below in combination with the drawings and embodiments.

[0032] In combination with Figures 1 to 7 the drawings, the screw refrigeration compressor of the present embodiment comprises a shell 1, a first rotor 2, a second rotor 3 and a communication shaft 4. The shell 1 is of a split structure and is composed of multiple parts in a detachable connection manner. The shell 1 is provided with an air inlet 5 and an air outlet 6. The first rotor 2 and the second rotor 3 are respectively rotatably connected inside the shell 1 and are in mutual engagement. The air inlet 5 is in communication with an air inlet cavity formed by the engagement of the first rotor 2 and the second rotor 3. The air outlet 6 is in communication with an air outlet cavity formed by the engagement of the first rotor 2 and the second rotor 3. A connecting channel 7 is provided between the air inlet 5 and the air outlet 6. The communication shaft 4 is located in the connecting channel 7 to control the on-off of the connecting channel 7.

[0033] At this time, in the screw refrigeration compressor of the present embodiment, by providing the communication shaft between the air inlet and the air outlet and controlling the on-off of the connecting channel between the air inlet and the air outlet by the communication shaft, the communication shaft can be controlled to connect the air inlet and the air outlet when the screw compressor is just started, so that the screw compressor will not be started under load, the load at start is reduced, and after the first rotor and the second rotor are stably rotated, the communication shaft is controlled to disconnect the air inlet and the air outlet, so that the screw compressor can work normally.

[0034] In combination with Figure 3 and Figure 7As shown, in the screw refrigeration compressor of this embodiment, a first push slider 8 and a second push slider 9 are further included. A first rotor shaft 10 connected to a bearing is provided at the end of the first rotor 2, and a second rotor shaft 11 connected to a bearing is provided at the end of the second rotor 3. One end of the first rotor shaft 10 extends outside the housing 1 and is connected to the drive motor. The first push slider 8 and the second push slider 9 are respectively slidably connected to the housing 1. The first push slider 8 is located on a side of the first rotor shaft 10 away from the second rotor shaft 11, and the second push slider 9 is located on a side of the second rotor shaft 11 away from the first rotor shaft 10. The first push slider 8 can move to form rotational contact with the first rotor shaft 10 and apply a force to the first rotor shaft 10 toward the second rotor shaft 11. The second push slider 9 can move to form rotational contact with the second rotor shaft 11 and apply a force to the second rotor shaft 11 toward the first rotor shaft 10.

[0035] In the screw refrigeration compressor of this embodiment, by providing a first pushing slider and a second pushing slider, a thrust toward the center can be applied to the first rotor shaft and the second rotor shaft respectively, that is, a thrust is applied to the first rotor shaft and the second rotor shaft to move closer to each other, so as to balance the outward thrust generated by the compressed gas on the two rotors when they are working, thereby reducing bearing wear and allowing the two rotors to rotate more stably and improve efficiency.

[0036] Combine Figure 7 As shown, the screw refrigeration compressor of this embodiment further includes a control rod 13, a first connecting rod 14, and a second connecting rod 15. The control rod 13 is slidably connected to the housing 1, and one end is simultaneously rotationally connected to one end of the first connecting rod 14 and one end of the second connecting rod 15. The other end of the first connecting rod 14 is rotationally connected to the first push slider 8, which is linearly slidably connected to the housing 1. The other end of the second connecting rod 15 is rotationally connected to the second push slider 9, which is linearly slidably connected to the housing 1.

[0037] At this time, by driving the control rod to move back and forth, the first connecting rod and the second connecting rod can respectively drive the first pushing slider to move back and forth, thereby controlling the effect of the first pushing slider on the first rotor shaft and the effect of the second pushing slider on the second rotor shaft.

[0038] In this embodiment, both the first pushing slider and the second pushing slider adopt a structural design of arc-shaped contact surface to increase the contact area between the pushing slider and the corresponding rotor shaft, thereby improving the stability of applying force to the rotor shaft.

[0039] Combine Figure 3 and Figure 4As shown, the screw refrigeration compressor of this embodiment also includes a gear pump consisting of a first gear 16 and a second gear 17. Furthermore, a first internal channel 18 is provided on the first rotor 2 along its axial direction and extends through the first rotor shaft 10. A second internal channel 19 is provided on the second rotor 3 along its axial direction and extends through the second rotor shaft 11. A liquid inlet cavity formed by the meshing of the first gear 16 and the second gear 17 communicates with a liquid inlet 20. A liquid outlet cavity formed by the meshing of the first gear 16 and the second gear 17 serves as the pump outlet 12 of the gear pump and communicates with the first internal channel 18. The first internal channel 18 and the second internal channel 19 are connected via an auxiliary channel located on the housing 1. The second internal channel 19 communicates with a liquid outlet 21 on the housing 1.

[0040] At this time, in the screw refrigeration compressor of this embodiment, by setting internal channels inside the two rotors respectively, the cooling medium output by the gear pump can pass through the internal channels of the two rotors in turn, directly taking away the heat generated by the two rotors when working, thereby achieving a better cooling effect.

[0041] Furthermore, in this embodiment, the first gear 16 is sleeved and fixed on the first rotor shaft 10, and the second gear 17 is sleeved and fixed on the second rotor shaft 11. In this case, when the first rotor and the second rotor rotate, the first gear and the second gear can be driven to rotate synchronously, thereby achieving synchronous output of the cooling medium.

[0042] In addition, the screw refrigeration compressor of this embodiment is further provided with a control valve located at the pump outlet of the gear pump to control the medium pressure at the pump outlet. Thus, when the first and second rotors begin to rotate, the control valve can be used to cause the gear pump to rotate at a low load, thereby reducing energy consumption. When the first and second rotors rotate stably, the control valve can be used to cause the gear pump to rotate at a high load, thereby outputting pressurized cooling medium and improving the cooling efficiency of the first and second rotors.

[0043] Combine Figure 1 and Figure 7 As shown, the screw refrigeration compressor of this embodiment is further provided with a control spring 22. The control spring 22 is connected to the control rod 13, driving the control rod 13 to move the first connecting rod 14 and the second connecting rod 15, thereby moving the first push slider 8 away from the first rotor shaft 10 and the second push slider 9 away from the second rotor shaft 11. Simultaneously, the pump outlet 12 of the gear pump communicates with the cavity 23 where the control rod 13 is located, outputting high-pressure medium to drive the control rod 13 to move against the control spring 22.

[0044] At this time, by controlling the cooling medium pressure of the pump outlet of the gear pump, the control spring driven control rod can be moved back and forth to control the reciprocating movement of the push slider relative to the corresponding rotor shaft, thereby exerting a thrust on the rotor shaft.

[0045] In combination Figure 1 As shown in the embodiment, the control valve specifically includes a valve body 24, a valve core 25, a valve core spring 26 and a one-way valve 27. The valve body 24 is provided with a first valve port 28, a second valve port 29 and a third valve port 30, the valve core 25 is located between the first valve port 28 and the second valve port 29, and the valve core spring 26 is connected with the valve core 25 to drive the valve core 25 to move relative to the valve body 24 to block the first valve port 28. The one-way valve 27 is in the form of a spring ball valve and is located on the valve core 25 to realize one-way communication between the third valve port 30 and the first valve port 28. The valve body 24 is rotationally connected to the shell 1 to control the communication between the third valve port 30 and the pump outlet 12 of the gear pump and the communication between the first valve port 28 and the first internal passage 18 through the transition passage 36, or to control the communication between the first valve port 28 and the pump outlet 12 of the gear pump and the communication between the second valve port 29 and the first internal passage 18 through the transition passage 36.

[0046] At this time, by rotating the valve body relative to the shell, the cooling medium pressure of the pump outlet of the gear pump can be adjusted, that is, the output pressure of the gear pump is adjusted. When the valve body is rotated to the third valve port in communication with the pump outlet of the gear pump and the first valve port in communication with the first internal passage, the cooling medium output by the gear pump can flow to the first valve port through the one-way valve in a low-load manner when flowing to the third valve port, and then flow out through the first internal passage and the second internal passage, while the cooling medium output by the gear pump cannot drive the control rod to move against the control spring, so that the push slider is away from the rotor shaft, the rotor shaft can rotate under no load, and the energy consumption is reduced. When the valve body is rotated to the first valve port in communication with the pump outlet of the gear pump and the second valve port in communication with the first internal passage, the cooling medium output by the gear pump can flow to the second valve port in the form of a load pressure by driving the valve core to overcome the valve core spring when flowing to the first valve port, and then flow out through the first internal passage and the second internal passage, while the cooling medium output by the gear pump can drive the control rod to move against the control spring, so that the push slider moves to provide a thrust to the rotor shaft, and the rotation of the rotor is more stable.

[0047] In combination Figure 1 As shown in the embodiment, the screw refrigeration compressor further includes a control motor 31, and the communication shaft 4 is provided with a through hole 32. The control motor 31 is fixed on the shell 1 and connected with the communication shaft 4 to drive the communication shaft 4 to reciprocating rotate relative to the shell 1 in the connection passage 7, so as to control the opening and closing of the through hole 32 and the connection passage 7, and further control the opening and closing relationship between the inlet 5 and the outlet 6 through the connection passage 7.

[0048] In combination Figure 1 And Figure 2 As shown in the screw refrigeration compressor of the embodiment, a driving rod 33, a driving gear 34 and a transmission gear 35 are further included. One end of the driving rod 33 is eccentrically connected with the end surface of the communication shaft 4 extending out of the shell 1, the other end of the driving rod 33 is eccentrically connected with the end surface of the driving gear 34, the driving gear 34 is rotationally connected on the shell 1 and is in meshing connection with the transmission gear 35, and the transmission gear 35 is coaxially sleeved and fixed on the end of the valve body 24 extending out of the shell 1.

[0049] At this time, the valve body is driven to rotate by the driving rod while the communication shaft is driven to rotate by the control motor, so as to change the pressure control of the cooling medium output by the gear pump through the control valve. Specifically, when the control motor drives the communication shaft to rotate to connect the communication channel, i.e. when the screw refrigeration compressor is in the starting state, the valve body is driven to rotate to the position shown in Figure 1 , i.e. the third valve port is in communication with the pump outlet of the gear pump, and the first valve port is in communication with the first internal channel, so that the push block is in a position away from the rotor shaft, and the rotor shaft can rotate freely; when the control motor drives the communication shaft to rotate 90 degrees to cut off the communication channel, i.e. when the screw refrigeration compressor is in the stable working state, the valve body is driven to rotate 180 degrees from the position shown in Figure 1 , i.e. the first valve port is switched to be in communication with the pump outlet of the gear pump, and the second valve port is in communication with the first internal channel, so that the cooling medium pressure output by the gear pump corresponds to the force of the valve core spring, and the cooling medium can push the control rod to overcome the control spring to move the push block to a position abutting against the rotor shaft, so as to apply a mutual approaching thrust to the two rotor shafts to balance the outward thrust of the gas on the two rotors during working, thereby reducing the bearing wear, and making the two rotors rotate more stably and improving the efficiency.

[0050] Among different embodiments, according to different designs and use environments, the transmission ratio between the driving gear and the transmission gear can be adjusted to change the rotational angle relationship between the communication shaft and the valve body, so as to meet the use requirements of different working conditions.

[0051] In combination Figures 1 to 7 As shown in the screw refrigeration compressor of the embodiment, the specific working process is as follows:

[0052] When the screw refrigeration compressor of the embodiment starts to work, the driving motor is started to drive the first rotor shaft 10 to rotate, and the first rotor 2 is driven to rotate, and under the cooperation between the first rotor 2 and the second rotor 3, the second rotor 3 and the second rotor shaft 11 are driven to rotate synchronously, and the first gear 16 and the second gear 17 are driven to rotate. At this time, the control motor 31 drives the communication shaft 4 to rotate to the state that the through hole 32 and the connecting channel 7 are in communication, that is, the intake port 5 and the exhaust port 6 are directly communicated through the connecting channel 7, so that the first rotor 2 and the second rotor 3 are in the state of idle rotation. The rotation of the first gear 16 and the second gear 17 introduces the cooling medium from the inlet 20, and pumps the cooling medium through the first gear 16 and the second gear 17. At this time, the valve body 24 is in communication with the first internal channel 18 through the first valve port 28, and the third valve port 30 is in communication with the pump outlet 12 of the gear pump, so that the cooling medium at the pump outlet 12 directly flows to the first valve port 28 through the one-way valve 27, flows to the outlet 21 through the first internal channel 18 and the second internal channel 19, and completes the cooling of the first rotor 2 and the second rotor 3, so that the first gear 16 and the second gear 17 are in the state of idle rotation.

[0053] When the first rotor 2 and the second rotor 3 are stably rotated, the control motor 31 is started to drive the communication shaft 4 to rotate by 90 degrees to the state that the through hole 32 and the connecting channel 7 are disconnected, that is, the connecting channel 7 between the intake port 5 and the exhaust port 6 is disconnected, so that the gas enters through the intake port 5, is compressed by the first rotor 2 and the second rotor 3, and is then discharged through the exhaust port 6. At the same time, the rotation of the communication shaft 4 drives the valve body 24 to rotate by 180 degrees through the driving rod 33, the driving gear 34 and the transmission gear 35, so that the first valve port 28 is switched to be in communication with the pump outlet 12 of the gear pump, and the second valve port 29 is in communication with the first internal channel 18, so that the pressure of the cooling medium pumped out of the first gear 16 and the second gear 17 to the pump outlet 12 is increased until the valve core 25 can overcome the valve spring 26 to flow from the first valve port 28 to the second valve port 29, and then flow to the outlet 21 through the first internal channel 18 and the second internal channel 19 to complete the cooling of the first rotor 2 and the second rotor 3. At the same time, the cooling medium with increased pressure flows to the cavity 23 and drives the control rod 13 to overcome the control spring 22 to move, so that the first pushing block 8 and the second pushing block 9 are respectively driven by the first connecting rod 14 and the second connecting rod 15 to move towards the first rotor shaft 10 and the second rotor shaft 11 respectively and apply radial force to the first rotor shaft 10 and the second rotor shaft 11 respectively, so as to overcome the outward radial force of the compressed gas on the first rotor 2 and the second rotor 3, so that the first rotor 2 and the second rotor 3 rotate more stably, and the service life of the bearing is prolonged.

Claims

1. A screw refrigeration compressor, characterized in that: The invention comprises a housing, a first rotor, a second rotor, and a connecting shaft; the housing is provided with an air inlet and an air outlet; the first rotor and the second rotor are respectively rotatably connected to the interior of the housing and mesh with each other; the air inlet is communicated with an air inlet cavity formed by the meshing of the first rotor and the second rotor, and the air outlet is communicated with an air outlet cavity formed by the meshing of the first rotor and the second rotor; a connecting channel is provided between the air inlet and the air outlet, and the connecting shaft is located in the connecting channel to control the opening and closing of the connecting channel; The screw refrigeration compressor further includes a first pushing slider and a second pushing slider, wherein a first rotor shaft is provided at an end portion of the first rotor, and a second rotor shaft is provided at an end portion of the second rotor; the first pushing slider and the second pushing slider are respectively slidably connected to the housing, the first pushing slider being located on a side of the first rotor shaft away from the second rotor shaft, and the second pushing slider being located on a side of the second rotor shaft away from the first rotor shaft; the first pushing slider is capable of moving to rotationally contact with the first rotor shaft and applying a force to the first rotor shaft toward the second rotor shaft; The second push slider is movable into rotational contact with the second rotor shaft and applies a force to the second rotor shaft toward the first rotor shaft.

2. The screw refrigeration compressor according to claim 1, characterized in that The screw refrigeration compressor also includes a control rod, a first connecting rod and a second connecting rod; one end of the control rod is simultaneously connected to one end of the first connecting rod and one end of the second connecting rod, the other end of the first connecting rod is connected to the first pushing slider, and the other end of the second connecting rod is connected to the second pushing slider.

3. The screw refrigeration compressor according to claim 2, characterized in that: The screw refrigeration compressor also includes a gear pump, wherein the first rotor is provided with a first internal channel extending along its axial direction, and the second rotor is provided with a second internal channel extending along its axial direction; the pump outlet of the gear pump is connected to the first internal channel, the first internal channel is connected to the second internal channel, and the second internal channel is connected to the liquid outlet.

4. The screw refrigeration compressor according to claim 3, characterized in that: The screw refrigeration compressor further comprises a control valve; the control valve is located at the pump outlet to control the medium pressure at the pump outlet.

5. The screw refrigeration compressor according to claim 4, characterized in that: The screw refrigeration compressor also includes a control spring; the control spring is connected to the control rod to drive the control rod to drive the first connecting rod and the second connecting rod to move, so that the first push slider is away from the first rotor shaft and the second push slider is away from the second rotor shaft; the pump outlet is connected to the cavity where the control rod is located to output high-pressure medium to drive the control rod to overcome the control spring and move.

6. The screw refrigeration compressor according to claim 5, characterized in that The control valve includes a valve body, a valve core, a valve core spring and a one-way valve; the valve body is provided with a first valve port, a second valve port and a third valve port; the valve core is located between the first valve port and the second valve port, and the valve core spring is connected to the valve core to drive the valve core to move relative to the valve body to block the first valve port; the one-way valve is located on the valve core and is used to connect the third valve port and the first valve port in one direction; the valve body is rotatably connected to the housing to control the third valve port to be connected to the pump outlet and the first valve port to be connected to the first internal channel, or to control the first valve port to be connected to the pump outlet and the second valve port to be connected to the first internal channel.

7. The screw refrigeration compressor according to claim 6, characterized in that The screw refrigeration compressor also includes a control motor, and a through hole is provided on the connecting shaft; the control motor is connected to the connecting shaft to drive the connecting shaft to rotate back and forth relative to the shell, thereby controlling the opening and closing of the through hole and the connecting channel.

8. The screw refrigeration compressor according to claim 7, characterized in that: The screw refrigeration compressor also includes a driving rod, a driving gear and a transmission gear; one end of the driving rod is eccentrically connected to the end face of the connecting shaft, and the other end of the driving rod is eccentrically connected to the end face of the driving gear. The driving gear is rotationally connected to the housing and meshes with the transmission gear. The transmission gear is coaxially sleeved and fixed to the end of the valve body.

9. The screw refrigeration compressor according to claim 3, characterized in that: The gear pump includes a first gear and a second gear that are meshed together; the first gear is sleeved and fixed on the first rotor shaft and / or the second gear is sleeved and fixed on the second rotor shaft, the liquid inlet is connected to the liquid inlet cavity formed by the meshing of the first gear and the second gear, and the pump outlet is connected to the liquid outlet cavity formed by the meshing of the first gear and the second gear.

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