Magnetic suspension motor structure for refrigeration

Abstract

The magnetic suspension motor structure comprises a motor shell, a motor stator and a motor rotor, the left end and the right end of the motor rotor are each provided with a magnetic suspension bearing module, and the inner wall of the motor shell is provided with a cooling flow channel which corresponds to the motor stator in position and facilitates flowing of a liquid refrigerant. The right end of the cooling flow channel is connected with a communication flow channel which is beneficial for a gaseous refrigerant formed after the liquid refrigerant is gasified to flow to the right end of the interior of the motor shell. The left end of the motor housing is provided with an output flow channel, and the output flow channel facilitates the output of a gaseous refrigerant flowing from right to left in the motor housing. The cooling device is reasonable in design, through the specially-designed cooling loop, the liquid refrigerant cools the motor stator firstly, the gaseous refrigerant formed after the liquid refrigerant is gasified flows from right to left in the motor shell, and cooling of the magnetic suspension bearing, the motor rotor and the motor stator is achieved; and the overall efficiency is improved while the heat dissipation requirements of the motor and the magnetic suspension bearing are effectively ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to a refrigeration magnetic levitation motor structure. BACKGROUND

[0002] In the field of refrigeration equipment (such as central air conditioning, industrial water chiller, heat pump unit, etc.), the motor as the core power component to drive the compressor rotation, its operation efficiency, stability and energy consumption level directly determines the overall performance of the refrigeration system. The traditional refrigeration motor adopts rolling bearing or sliding bearing support structure. With the continuous improvement of the current refrigeration field application speed, the traditional motor structure has the following problems in operation: 1. High mechanical loss and energy consumption: the traditional motor has low efficiency; 2. Reliability and service life are limited: mechanical bearings need to rely on lubrication, and long-term use cannot guarantee stable operation; 3. Vibration and noise problem is prominent: mechanical friction and bearing gap will inevitably increase the vibration of the motor operation, which is difficult to meet the demand of modernization scene for low noise comfort; 4. Poor high-speed adaptability. The refrigeration system is developing towards miniaturization and high power density, and the motor speed is gradually increasing, and the traditional mechanical bearing is difficult to meet the high-speed operation requirement.

[0003] To solve the above problems, magnetic levitation bearing technology is introduced into the field of refrigeration motor. Because of the characteristics of no bearing friction loss and no need for lubrication, magnetic levitation bearing technology can easily meet the high-speed application scene of tens of thousands of revolutions. However, the existing refrigeration magnetic levitation motor still needs to be improved: on the one hand, the heat loss of part of the magnetic levitation motor is not well adapted to the heat dissipation demand of the refrigeration system, resulting in too high operating temperature rise, which affects the suspension stability; on the other hand, the suspension force regulation precision of part of the structure is low, and under the fluctuation of refrigeration working condition, the shaft displacement fluctuation is easy to appear, which increases the control complexity. SUMMARY

[0004] The present application improves the existing problems in the prior art, that is, the technical problem to be solved by the present application is to provide a refrigeration magnetic levitation motor structure, which is reasonable in design, suitable for refrigeration scene, and takes into account high efficient heat dissipation and high stability.

[0005] In order to achieve the above object, the technical scheme adopted by the present application is: a refrigeration magnetic suspension motor structure, comprising a motor shell, a motor stator and a motor rotor arranged in the motor shell and matched with each other, magnetic suspension bearing modules are arranged at the left and right ends of the motor rotor respectively, a cooling flow channel corresponding to the position of the motor stator and facilitating the flow of liquid refrigerant is arranged on the inner wall of the motor shell, a communication flow channel facilitating the flow of gaseous refrigerant formed after the gasification of liquid refrigerant to the right end inside the motor shell is connected to the right end of the cooling flow channel; an output flow channel is arranged at the left end of the motor shell, which facilitates the output of gaseous refrigerant flowing from right to left inside the motor shell.

[0006] Further, the cooling flow channel is in a spiral shape along the axial direction of the motor shell.

[0007] Further, an input flow channel for connecting with a refrigeration system is arranged at the lower part of the motor shell, the input flow channel is in communication with the left end of the cooling flow channel, and the refrigeration system introduces the external liquid refrigerant into the cooling flow channel through the input flow channel.

[0008] Further, a pneumatic shell is arranged at the left end of the motor shell, a volute is arranged in the pneumatic shell, and an impeller connected with the left end of the motor rotor is arranged in the volute; the output flow channel is arranged at the upper end of the pneumatic shell, and the gaseous refrigerant output by the output flow channel is sucked into the volute through the suction port of the impeller.

[0009] Further, the volute and the magnetic suspension bearing module located on the left side have a left side flow space facilitating the flow of gaseous refrigerant, the left side flow space is in communication with the output flow channel, and the gaseous refrigerant passing through the magnetic suspension bearing module located on the left side enters the output flow channel through the left side flow space.

[0010] Further, the impeller is a closed impeller, and the middle part of the impeller is locked and fixed to the left end of the motor rotor through the cooperation of a locking screw and a locking nut.

[0011] Further, a tail end cover is arranged at the right end of the motor shell, the tail end cover and the magnetic suspension bearing module located on the right side have a right side flow space facilitating the flow of gaseous refrigerant, and the gaseous refrigerant output by the communication flow channel enters the right side flow space and then passes through the magnetic suspension bearing module located on the right side.

[0012] Further, the magnetic suspension bearing module comprises a bearing mounting seat fixed in the motor shell, a position sensor is arranged in the bearing mounting seat, a radial magnetic suspension coil is arranged on the side of the position sensor facing the motor stator, and an axial magnetic suspension coil is arranged on the side of the position sensor facing away from the motor stator.

[0013] Further, the left and right ends of the motor rotor are respectively connected with auxiliary bearings, and the auxiliary bearings are installed on the magnetic suspension bearing module through bearing pressing plates.

[0014] Further, the motor rotor is a surface-mounted permanent magnet motor rotor, the motor shell is made of aluminum-magnesium alloy by casting processing, and the motor shell and the motor stator are installed through interference fit by heating.

[0015] Compared with the prior art, the application has the following effects: the application has reasonable design, liquid refrigerant is used to cool the motor stator through the specially designed cooling circuit, gaseous refrigerant formed after the liquid refrigerant is vaporized flows from right to left inside the motor shell, and the magnetic suspension bearing, the motor rotor and the motor stator are cooled, the heat dissipation requirement of the motor and the magnetic suspension bearing is effectively ensured, the overall efficiency is increased, and the refrigeration system energy efficiency, reliability and maintenance cost are improved. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic view of a front cross-sectional structure of an embodiment of the application; Figure 2 is a schematic view of a cooling circuit of an embodiment of the application; Figure 3 is Figure 1 is an enlarged schematic view of A in the figure.

[0017] In the figure: 1-motor shell; 2-motor stator; 3-motor rotor; 4-magnetic suspension bearing module; 41-bearing mounting seat; 42-axial magnetic suspension coil; 43-position sensor; 44-radial magnetic suspension coil; 5-tail end cover; 6-auxiliary bearing; 7-bearing pressing plate; 8-pneumatic shell; 9-impeller; 10-locking screw; 11-locking nut; 12-cooling flow channel; 13-communication flow channel; 14-output flow channel; 15-input flow channel; 16-left side flow space; 17-right side flow space; 18-suction port of the impeller; 19-volute. DETAILED DESCRIPTION

[0018] The application will be further described in detail below in combination with the drawings and specific embodiments.

[0019] In the description of the application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0020] As shown in Figures 1 to 3 The application is a refrigeration magnetic suspension motor structure, which is designed to adapt to refrigeration scenarios and take into account high heat dissipation and high stability. The structure comprises a motor shell 1, a motor stator 2 and a motor rotor 3 arranged inside the motor shell 1 and adapted to each other. The motor stator 2 is installed inside the motor shell 1, and the motor rotor 3 penetrates the motor stator 2 along the left-right direction. Magnetic suspension bearing modules 4 are arranged at the left and right ends of the motor rotor 3, respectively. The magnetic suspension bearing modules 4 at both ends generate magnetic force to keep the motor rotor 3 in a suspended state at all times. Further specifically, the inner wall of the motor shell 1 is provided with a cooling flow channel 12 corresponding to the position of the motor stator 2 and facilitating the flow of liquid refrigerant. The liquid refrigerant flowing in the cooling flow channel 12 dissipates heat for the motor stator 2, and the liquid refrigerant vaporizes after absorbing heat. The right end of the cooling flow channel 12 is connected with a communication flow channel 13, which facilitates the flow of gaseous refrigerant formed after the vaporization of the liquid refrigerant from left to right to the right end inside the motor shell 1. The left end of the motor shell 1 is provided with an output flow channel 14, which facilitates the output of the gaseous refrigerant flowing from right to left inside the motor shell 1. When working, the liquid refrigerant flowing in the cooling flow channel 12 dissipates heat for the motor stator 2, and the liquid refrigerant vaporizes after absorbing heat. The gaseous refrigerant formed after vaporization flows to the right end inside the motor shell 1 through the communication flow channel 13, and then flows from right to left inside the motor shell 1, first passing through the magnetic suspension bearing module 4 located on the right side, then passing through the motor stator 2 and the motor rotor 3, and finally passing through the magnetic suspension bearing module 4 located on the left side, to complete the cooling of the above components and then output from the output flow channel 14.

[0021] In this embodiment, the cooling flow channel 12 is in a spiral shape along the axis direction of the motor shell. By designing a spiral cooling flow channel, the flow path of the liquid refrigerant can be extended to facilitate sufficient absorption of heat and contact vaporization, thereby improving the heat dissipation effect of the motor stator.

[0022] In this embodiment, the lower part of the motor shell 1 is provided with an input flow channel 15 for connecting with the refrigeration system along the radial direction. The input flow channel 15 is in communication with the left end of the cooling flow channel 12. By utilizing the characteristics of the refrigeration cycle system, the refrigeration system introduces the external liquid refrigerant into the cooling flow channel 12 through the input flow channel 15. The communication flow channel is arranged at the lower part of the motor shell and extends along the axis direction of the motor shell.

[0023] In this embodiment, the left end of the motor housing 1 is provided with a one-piece cast processing pneumatic shell 8, which is fixed on the motor housing 1 by bolt connection; the pneumatic shell 8 is provided with a volute 19, a pressure expansion flow channel and other compression refrigeration structure forms, the volute 19 is provided with an impeller 9 connected with the left end of the motor rotor 3; the output flow channel 14 is arranged on the upper end of the pneumatic shell 8 and extends along the axis direction of the pneumatic shell 8, the output port of the output flow channel 14 is located on the same side with the suction port 18 of the impeller, the gaseous refrigerant output by the output flow channel 14 is sucked into the suction port 18 of the impeller, so that the gaseous refrigerant reenters the refrigeration system circulation.

[0024] In this embodiment, the impeller 9 is a precision cast closed impeller, which can realize high-efficiency and high-performance airflow transmission. Further, the middle part of the impeller 9 is locked and fixed on the left end of the motor rotor 3 through the cooperation of the locking screw 10 and the locking nut 11.

[0025] In this embodiment, the volute 19 and the magnetic suspension bearing module 4 located on the left side have a left flow space 16 for facilitating the flow of gaseous refrigerant, the left flow space 16 is communicated with the output flow channel 14, and the gaseous refrigerant passing through the magnetic suspension bearing module 4 located on the left side enters the output flow channel 14 through the left flow space 16.

[0026] In this embodiment, the right end of the motor housing 1 is provided with a tail end cover 5, which is fixed on the motor housing 1 by bolt connection to form a closed motor structure.

[0027] In this embodiment, the tail end cover 5 and the magnetic suspension bearing module 4 located on the right side have a right flow space 17 for facilitating the flow of gaseous refrigerant, the gaseous refrigerant output by the communication flow channel 13 enters the right flow space 17 and then passes through the magnetic suspension bearing module 4 located on the right side.

[0028] In this embodiment, the magnetic suspension bearing module 4 includes a bearing mounting seat 41 fixed in the motor housing 1 by bolts, the bearing mounting seat 41 is provided with a position sensor 43, the position sensor 43 is provided with a radial magnetic suspension coil 44 facing the side where the motor stator 2 is located, and the position sensor 43 is provided with an axial magnetic suspension coil 42 facing away from the side where the motor stator 2 is located; further, the axial magnetic suspension coil 42, the position sensor 43 and the radial magnetic suspension coil 44 are fixed in the bearing mounting seat 41 by thermal assembly, and the axial magnetic suspension coil 42, the position sensor 43 and the radial magnetic suspension coil 44 are sleeved on the outside of the motor rotor. The magnetic suspension bearing module is composed of a bearing mounting seat, an axial magnetic suspension coil, a position sensor and a radial magnetic suspension coil; the left and right magnetic suspension bearing modules are the same, which realizes universality and interchangeability, enhances assembly efficiency and reliability, and reduces subsequent maintenance and replacement cost.

[0029] The working principle of the magnetic suspension motor is that the magnetic force generated by the magnetic suspension bearing modules 4 installed at both ends is used to keep the motor rotor 3 in a suspended state at all times. When the motor is running, the position sensor 43 of the magnetic suspension bearing module 4 can detect the position change of the rotor shaft in real time, and transmit the position signal to the bearing controller. The bearing controller converts the collected position signal into a control signal, controls the current size in the magnetic suspension coil, and drives the motor rotor 3 shaft to return to the center position. When the motor is running, no matter whether the motor rotor is subjected to radial or axial load, the rotor can always be in a stable equilibrium state, ensuring the smooth running of the motor.

[0030] In this embodiment, the left and right ends of the motor rotor 3 are respectively connected with auxiliary bearings 6, and the motor rotor 3 can rotate smoothly on the auxiliary bearings 6. The auxiliary bearings 6 are installed on the magnetic suspension bearing modules 4 through bearing pressing plates 7. Specifically, the auxiliary bearings 6 are arranged in the axial magnetic suspension coil 42, and the bearing pressing plate 7 is arranged on the upper cover of the auxiliary bearing 6. The bearing pressing plate 7 is fixed on the axial magnetic suspension coil 42 by bolt connection, so as to realize the installation of the auxiliary bearing on the magnetic suspension bearing module 4. The bearing pressing plate 7 keeps the auxiliary bearing 6 stable during the operation of the motor rotor, avoiding position change due to vibration. Preferably, the auxiliary bearing 6 is a high-speed ceramic ball bearing. The auxiliary bearing 6 is installed on the magnetic suspension bearing modules 4 at both sides, which supports the motor rotor when the motor is not started, and can withstand a certain axial impact load. At the same time, when the magnetic suspension bearing fails at high speed, the auxiliary bearing 6 can withstand at least 20 times of high-speed drop working condition.

[0031] In this embodiment, the motor rotor 3 is a surface-mounted permanent magnet motor rotor. In order to ensure the high-speed friction performance, the surface roughness is required to be 0.8 μm.

[0032] In this embodiment, the motor housing 1 is made of aluminum-magnesium alloy casting processing, and the inside is processed with a surface and a threaded hole for installing the motor stator, the magnetic suspension bearing module and the like. The cooling flow channel and the communication flow channel in the motor housing are cast together with the motor housing.

[0033] In this embodiment, the motor housing 1 and the motor stator 2 are installed by interference fit through heating. Specifically, the magnetic suspension bearing module 4 on the right side is connected and installed in the motor housing 1 through the bolt, the right end of the motor rotor 3 passes through the motor stator 2, and is fixed on the magnetic suspension bearing module 4 on the right side. The magnetic suspension bearing module 4 on the left side passes through the left end of the motor rotor 3, and is fixed on the motor housing 1 by bolt connection.

[0034] As Figure 2As shown, the cooling circuit is schematically illustrated as follows: the motor housing 1 is provided with a spiral cooling flow channel 12, and the liquid refrigerant in the refrigeration system circulation enters the spiral cooling flow channel 12 from the lower part of the motor housing 1 (i.e. the input flow channel 13), and then the spiral cooling flow channel 12 cools the motor stator 2. The liquid refrigerant is gasified after absorbing heat in the spiral cooling flow channel 12, and enters the right side of the motor housing 1. The gaseous refrigerant sequentially passes through the magnetic suspension bearing module 4 located on the right side, the motor stator 2, the motor rotor 3, and the magnetic suspension bearing module 4 located on the left side from the inside of the motor housing 1, and completes the cooling of the above components. Finally, the gaseous refrigerant returns to the impeller 9 side through the output flow channel 14 in the pneumatic housing 8, and reenters the refrigeration system circulation through the suction port 18 of the impeller. The cooling flow space is formed by the cooling flow channel, the communication flow channel, the output flow channel and the space inside the motor housing, and the special refrigerant compatibility design is realized, so that the refrigerant can be introduced into the motor for cooling, the refrigeration system circulation system is fully utilized, and the overall efficiency is effectively ensured while the motor heat dissipation demand is ensured.

[0035] The advantages of the present application are: (1) The motor runs reliably and stably, and the magnetic suspension bearing module and the high-speed motor structure are combined together in a small housing space. The magnetic suspension bearing adopts a modular assembly design, the coil and the position sensor are sequentially assembled in the special bearing mounting seat, the left and right magnetic suspension bearings are universal and interchangeable, the assembly efficiency and reliability are further enhanced, and the subsequent maintenance and replacement cost is reduced. The reasonable space structure and wire layout further improve the anti-interference ability of the electrical system under the premise of reducing the equipment volume, so that the equipment can run stably and reliably for a long time.

[0036] (2) The motor uses a special refrigerant compatibility design, so that the refrigerant can be introduced into the motor for cooling, the refrigeration system circulation system is fully utilized, and the overall efficiency is effectively ensured while the motor heat dissipation demand is ensured.

[0037] If the present application discloses or involves mutually fixed connected parts or structural members, unless otherwise stated, the fixed connection can be understood as: detachable fixed connection (such as bolt or screw connection), and can also be understood as: non-detachable fixed connection (such as riveting, welding), of course, the mutual fixed connection can also be replaced by an integral structure (such as using casting process to integrally form and manufacture) (except for obvious cases that cannot use integral forming process).

[0038] In addition, the terms used to represent the position relationship or shape in any of the above disclosed technical solutions of the present application include the approximate, similar or close state or shape unless otherwise stated.

[0039] Any of the components provided herein can be assembled components or unitary components manufactured by an integral molding process.

[0040] Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalent replacements; without departing from the spirit of the technical solutions of the present application, they should be covered in the technical solution range of the present application claimed.

Claims

1. A magnetic levitation motor structure for refrigeration, comprising a motor housing (1), a motor stator (2) and a motor rotor (3) disposed inside the motor housing (1) and adapted thereto, wherein magnetic levitation bearing modules (4) are respectively disposed at the left and right ends of the motor rotor (3), characterized in that: The inner wall of the motor housing (1) is provided with a cooling channel (12) corresponding to the position of the motor stator (2) to facilitate the flow of liquid refrigerant. The right end of the cooling channel (12) is connected to a connecting channel (13) to facilitate the flow of gaseous refrigerant formed after the liquid refrigerant is vaporized to the right end of the motor housing (1). The left end of the motor housing (1) is provided with an output channel (14) to facilitate the output of gaseous refrigerant flowing from right to left inside the motor housing (1).

2. The magnetic levitation motor structure for refrigeration according to claim 1, characterized in that: The cooling channel (12) is spiral-shaped along the axial direction of the motor housing (1).

3. A magnetic levitation motor structure for refrigeration according to claim 1 or 2, characterized in that: The lower part of the motor housing (1) is provided with an input channel (15) for connecting to the refrigeration system. The input channel (15) is connected to the left end of the cooling channel (12). The refrigeration system introduces external liquid refrigerant into the cooling channel (12) through the input channel (15).

4. The magnetic levitation motor structure for refrigeration according to claim 1, characterized in that: A pneumatic housing (8) is provided at the left end of the motor housing (1), and a volute (19) is provided inside the pneumatic housing (8). An impeller (9) connected to the left end of the motor rotor (3) is provided inside the volute (19). The output channel (14) is provided at the upper end of the pneumatic housing (8), and the gaseous refrigerant output from the output channel (14) is drawn in by the air intake (19) of the impeller.

5. The magnetic levitation motor structure for refrigeration according to claim 4, characterized in that: The volute (19) and the magnetic levitation bearing module (4) located on the left side have a left flow space (16) to facilitate the flow of gaseous refrigerant. The left flow space (16) is connected to the output channel (14). The gaseous refrigerant passing through the magnetic levitation bearing module (4) located on the left side enters the output channel (14) through the left flow space.

6. The magnetic levitation motor structure for refrigeration according to claim 4, characterized in that: The impeller (9) is a closed impeller, and the middle part of the impeller (9) is locked to the left end of the motor rotor (3) by the locking screw (10) and the locking nut (11).

7. The magnetic levitation motor structure for refrigeration according to claim 1, characterized in that: The motor housing (1) is provided with a tail end cover (5) at the right end. There is a right flow space (17) between the tail end cover (5) and the magnetic levitation bearing module (4) located on the right side to facilitate the flow of gaseous refrigerant. The gaseous refrigerant output from the connecting channel (13) enters the right flow space (17) and passes through the magnetic levitation bearing module (4) located on the right side.

8. The magnetic levitation motor structure for refrigeration according to claim 1, characterized in that: The magnetic levitation bearing module (4) includes a bearing mounting base (41) fixed inside the motor housing (1). A position sensor (43) is provided inside the bearing mounting base (41). A radial magnetic levitation coil (44) is provided on the side of the position sensor (43) facing the motor stator (2), and an axial magnetic levitation coil (42) is provided on the side of the position sensor (43) facing away from the motor stator (2).

9. The magnetic levitation motor structure for refrigeration according to claim 1, characterized in that: The left and right ends of the motor rotor (3) are respectively connected to auxiliary bearings (6), and the auxiliary bearings (6) are installed on the magnetic levitation bearing module (4) through bearing pressure plate (7).

10. The magnetic levitation motor structure for refrigeration according to claim 1, characterized in that: The motor rotor (3) is a surface-mounted permanent magnet motor rotor; the motor housing (1) is made of aluminum-magnesium alloy casting; the motor housing (1) and the motor stator (2) are installed by interference fit through heating.

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