An electric machine

Abstract

The application provides a motor, and belongs to the technical field of motors.The motor comprises a shell, motor windings and a magneto-electric encoder arranged on the inner and outer sides of the shell respectively; the motor further comprises a protection structure arranged between the motor windings and the magneto-electric encoder, and the protection structure is configured to protect the magneto-electric encoder; the protection structure comprises a magnetic isolation part and a heat insulation part; the magnetic isolation part is configured to shield the alternating magnetic field generated by the motor windings from being transmitted to the magneto-electric encoder to protect the magneto-electric encoder, and the heat insulation part is configured to block the heat generated by the motor windings from being transmitted to the magneto-electric encoder to protect the magneto-electric encoder doubly. The protection structure composed of the heat insulation part and the magnetic isolation part can protect the magneto-electric encoder in the motor doubly, and the stability of the motor during operation is improved as a whole.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electric machines, and particularly relates to an electric machine. BACKGROUND

[0002] At present, the existing electric machines are generally of a rear brake structure, that is, a brake is adjacent to a magneto-encoder detection assembly. The magneto-encoder is fixed on a rotor shaft of the electric machine and is used to detect the position of a magnetic pole of the electric machine and the rotation angle and speed. The end cover on which the magneto-encoder is installed often produces heat during the operation of the stator and the brake, and has magnetism. The heat is easily transferred axially to the magneto-encoder and the end cover with magnetism, which can cause signal interference to the magneto-encoder, thereby reducing the accuracy of the signal collected by the magneto-encoder, and further affecting the precision of the speed, torque and position control of the servo motor.

[0003] Therefore, the present application is proposed. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide an electric machine.

[0005] To solve the above technical problems, the present application provides an electric machine. The electric machine comprises a machine shell, an electric machine winding and a magneto-encoder arranged on the inside and outside of the machine shell respectively.

[0006] The electric machine further comprises a protection structure arranged between the electric machine winding and the magneto-encoder. The protection structure is configured to protect the magneto-encoder.

[0007] The protection structure comprises a magnetic isolation part and a heat insulation part.

[0008] The magnetic isolation part is configured to shield the alternating magnetic field generated by the electric machine winding from being transmitted to the magneto-encoder, thereby providing a first protection for the magneto-encoder. The heat insulation part is configured to block the heat generated by the electric machine winding from being transmitted to the magneto-encoder, thereby providing a second protection for the magneto-encoder.

[0009] In the above technical solution, the protection structure is installed outside the machine shell. The magnetic isolation part of the protection structure is connected to the machine shell, and the heat insulation part of the protection structure is connected to the magneto-encoder.

[0010] In the above technical solution, the heat insulation part is installed on the magnetic isolation part, and the side of the heat insulation part connected to the magneto-encoder protrudes from the magnetic isolation part, so that a gap is left between the magneto-encoder and the magnetic isolation part.

[0011] In the above technical solution, a groove is formed on the machine shell for embedding the magnetic isolation part. The magnetic isolation part is embedded in the groove and fixedly connected to the machine shell.

[0012] In the above technical solution, the magnetic isolation part is detachably connected to the machine shell.

[0013] In the above technical solution, the screw hole is arranged on the magnetic isolation part, and the magnetic isolation plate is installed on the shell through the screw.

[0014] In the above technical solution, the magnetic isolation part and the shell are connected through glue.

[0015] In the above technical solution, the magnetic isolation part and the shell are integrally formed.

[0016] In the above technical solution, the first installation hole of the stepped type is arranged through the magnetic isolation part, the heat insulation part is embedded in the heat insulation part installation hole and at least partially protrudes out of the first installation hole, and the second installation hole is arranged through the heat insulation part and is in communication with the first installation hole.

[0017] The third installation hole is arranged on the magneto-encoder, the magneto-encoder is installed on the heat insulation part through the long shaft screw and is installed on the shell through the heat insulation part and the magnetic isolation part, and the long shaft screw is made of stainless steel.

[0018] In the above technical solution, the material of the magnetic isolation part is a magnetic conductor, and the heat insulation part is a thermal insulator.

[0019] In the above technical solution, the magnetic isolation part is a circular plate made of 45# steel, and the heat insulation part is a plastic heat insulation block arranged on the circular plate.

[0020] In the above technical solution, the shell includes a shell body with an opening and an end cover arranged on the opening of the shell body.

[0021] The motor winding includes a rotating shaft, a front bearing, a stator, a rear bearing and a brake arranged along the axis of the rotating shaft in sequence.

[0022] The rotating shaft has a first axial end and a second axial end, the end cover is arranged away from the first axial end, and the protection structure is fixedly installed on the surface of the end cover.

[0023] The carbon steel shaft sleeve is arranged in the magneto-encoder, the shaft hole is arranged through the magnetic isolation part, and the second axial end of the rotating shaft is connected to the carbon steel shaft sleeve through the shaft hole.

[0024] In the above technical solution, the motor is a servo motor.

[0025] Compared with the prior art, the above technical solution has the following beneficial effects:

[0026] The protective structure composed of the heat insulation part and the magnetic shielding part can effectively reduce the heat transfer from the motor to the magneto-encoder during the operation of the motor, reduce the temperature rise of the magneto-encoder, so that the motor design can not be limited by the excessive temperature rise of the encoder, and the power density of the motor is improved. The performance and stability of the motor during operation will be further improved, and at the same time, the influence of the alternating magnetic field generated by the brake emergency brake on the magneto-encoder can be shielded, ensuring that the signal picked up by the magneto-encoder is the accurate and effective speed and angle information of the motor, and ensuring the accuracy of the motor speed, torque and position control.

[0027] Secondly, the magnetic shielding part in the application is easy to realize in the processing technology, and has low assembly requirement, can effectively shield the influence of external alternating magnetic field on the magneto-encoder 3, and greatly reduces the manufacturing cost of the motor.

[0028] The specific embodiments of the application will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0029] The accompanying drawings are part of the present application and serve to provide a further understanding of the present application, the schematic embodiments of the present application and the description thereof serve to explain the present application, but do not constitute an improper limitation on the present application. Obviously, the accompanying drawings in the following description are only some embodiments, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings. In the drawings:

[0030] Figure 1 is a schematic diagram of the internal structure of the motor embodiment of the present application;

[0031] Figure 2 is Figure 1 is a schematic diagram of the internal structure when the protective structure and the magneto-encoder are connected in the embodiment;

[0032] Figure 3 is Figure 2 is a schematic diagram of the three-dimensional structure of the protective structure in the embodiment;

[0033] Figures 1-3 In the embodiment: 1-housing, 11-housing, 12-end cover, 2-motor winding, 21-rotating shaft, 22-front bearing, 23-stator, 24-rear bearing, 25-brake, 3-magneto-encoder, 41-magnetic shielding part, 42-heat insulation part,

[0034] It should be noted that these drawings and written descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0035] In the description of the present application, it should be pointed out that the terms "in", "out" and the like indicate the position or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element 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 present application.

[0036] In the description of the present application, it should be pointed out that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "contact", "communication" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0037] At present, the existing motor is generally a brake rear structure, that is, the brake is adjacent to the magneto-encoder detection assembly. The magneto-encoder is fixed on the motor rotor shaft, which is used to detect the motor magnetic pole position, angle and speed. The end cover of the magneto-encoder is often heated due to the heat generated by the stator and the brake during operation and has magnetism, and the heat is easily transmitted axially to the magneto-encoder and the end cover with magnetism, which can interfere with the magneto-encoder, thereby reducing the accuracy of the magneto-encoder signal acquisition, and further affecting the precision of the speed, torque and position control of the servo motor. The present application can isolate the magnetic field and heat generated in the machine shell by setting the protection structure, avoiding the transmission of the magnetic field and heat to the magneto-encoder and affecting the operating efficiency of the motor.

[0038] In order to further illustrate the technical solutions in the present application, the following specific embodiments are provided in combination with the drawings. Figures 1-3

[0039] Embodiment 1

[0040] Before the motor in the embodiments of the present application is described, the conventional motor is first introduced.

[0041] The main components of the conventional motor with encoder include: shaft, machine shell, stator, brake, rear end cover and magneto-encoder. Because the motor has high requirements for corrosion resistance and light weight, the machine shell and the end cover are made of aluminum ADC12 material, and the shaft is made of 45# steel with good structural strength. The working principle of the motor is that the stator is connected with alternating current, and the alternating magnetic field generated thereby interacts with the rotor core magnetic field, thereby driving the rotation of the shaft, and the magneto-encoder at the end of the shaft detects the motor speed and angle information, and feeds back these information to the servo drive controller, thereby realizing the precise control of the servo motor.

[0042] ​Because of the heat loss of motor, such as iron loss and copper loss, the motor will generate a lot of heat through the rear end cover and the rotor shaft to the encoder part in a long time running. The alternating magnetic field will be generated in the process of the brake being powered and losing power. The high temperature of the encoder and the alternating magnetic field from the outside will affect the detection of the encoder signal and damage the encoder, and then cause the motor to work abnormally.

[0043] In order to solve the above-mentioned problems, the motor provided in the embodiments of the present application is shown in Figure 1 The motor includes a shell 1, a motor winding 2 and a magneto-encoder 3 arranged on the inside and outside of the shell 1 respectively. Specifically, a magneto-encoder mounting shell is arranged outside the magneto-encoder 3 so that the magneto-encoder 3 can work in the magneto-encoder mounting shell.

[0044] The motor further includes a protection structure 4 arranged between the motor winding 2 and the magneto-encoder 3. The protection structure 4 is configured to protect the magneto-encoder 3. Specifically, the protection structure includes a magnetic shielding part 41 and a heat shielding part 42. The magnetic shielding part 41 is configured to shield the alternating magnetic field generated by the motor winding 2 in operation from being transmitted to the magneto-encoder 3 to provide a first protection for the magneto-encoder 3. The heat shielding part 42 is configured to block the heat generated by the motor winding 2 in operation from being transmitted to the magneto-encoder 3 to provide a second protection for the magneto-encoder 3.

[0045] Compared with the conventional motor, the motor in the embodiments of the present application can shield the influence of the alternating magnetic field generated by the motor winding 2 in operation on the magneto-encoder 3 under the action of the magnetic shielding part 41 in the protection structure 4, so as to ensure that the signal picked up by the magneto-encoder is the accurate and effective speed and angle information of the motor. The heat generated by the motor winding 2 in operation can be effectively reduced from being transmitted to the magneto-encoder 3 under the action of the heat shielding part 42 in the protection structure 4, so as to reduce the temperature of the magneto-encoder 3 in operation, and make the design power density of the motor not limited to the upper limit of the temperature rise of the magneto-encoder 3, thereby ensuring the stable and safe operation of the motor.

[0046] In order to make the technical scheme of the present application more clearly understood, the protection structure 4 will be described in detail as follows:

[0047] As shown in Figure 1 In the embodiments of the present application, the protection structure 4 is installed outside the shell 1. The magnetic shielding part 41 in the protection structure 4 is connected with the shell 1, and the heat shielding part 42 in the protection structure 4 is connected with the magneto-encoder 3.

[0048] Specifically, as shown in Figure 2As shown, the thermal insulation part 42 is installed on the magnetic isolation part 41, and the side of the thermal insulation part 42 connected with the magneto- electric encoder 3 protrudes from the magnetic isolation part 41 to leave a gap between the magneto- electric encoder 3 and the magnetic isolation part 41, so as to increase and isolate the distance and contact between the magneto- electric encoder 3 and the shell 1, block the heat transfer from the motor itself to the magneto- electric encoder 3 when the motor is running, and effectively reduce the temperature of the magneto- electric encoder 3 when running, so as to ensure that the motor can run stably.

[0049] In particular, in order not to occupy more space of the motor when installing the protection structure 4, in the embodiment of the application, a groove is formed on the shell 1 for embedding the magnetic isolation part 42. When installing the protection structure 4, the magnetic isolation part 42 is embedded in the groove and fixedly connected with the shell 1.

[0050] The following will specifically describe how the magnetic isolation part 41 is installed on the shell 1.

[0051] As shown in the figure, Figure 3 In the embodiment of the application, the magnetic isolation part 41 is detachably connected with the shell 1. Specifically, screw holes are formed on the magnetic isolation part 41. Preferably, three groups of screw holes are formed. When installing the magnetic isolation part 41, the magnetic isolation part 41 is installed on the shell 1 by screws, that is, the screws pass through the screw holes on the magnetic isolation part 41 to fixedly install the magnetic isolation part 41 in the groove at the end of the shell 1.

[0052] It should be noted that in some alternative embodiments, the magnetic isolation part 41 can also be fixedly installed on the shell 1 by other ways, for example, the magnetic isolation part 41 can be fixedly connected with the shell 1 by glue, and for example, the magnetic isolation part 41 can also be integrally formed. As long as the magnetic isolation part 41 can be fixedly installed on the shell 1, the specific installation way of the magnetic isolation part 41 is not limited in the embodiment. In the embodiment of the application, the magnetic isolation part 41 is detachably installed on the shell 1 mainly to facilitate the subsequent replacement and maintenance of the magnetic isolation part 41.

[0053] The following will specifically describe how the thermal insulation part 42 is installed on the magnetic isolation part 41.

[0054] As shown in the figure, Figure 3As shown, the first mounting hole of the magnetic isolation portion 41 is a stepped hole, the thermal insulation portion 42 is embedded in the thermal insulation portion mounting hole and at least partially protrudes out of the first mounting hole, the second mounting hole is formed in the thermal insulation portion 42 and is in communication with the first mounting hole, and the third mounting hole is formed in the magneto- electric encoder 3. The magneto-electric encoder 3 is installed on the thermal insulation portion 42 through a long shaft screw and is installed on the casing 1 through the thermal insulation portion 42 and the magnetic isolation portion 41. Since the bracket of the magneto-electric encoder 3 is made of metal material, the long shaft screw is made of stainless steel (non-magnetic). It should be noted that the first mounting hole is set to be stepped in the embodiment of the present application, which is mainly to prevent the thermal insulation portion 42 from being separated from the first mounting hole when the thermal insulation portion 42 is installed in the first mounting hole. Of course, in some alternative embodiments, the first mounting hole can also be set to be a through hole with equal inner diameter. When the first mounting hole is a hole with equal inner diameter, the thermal insulation portion 42 and the first mounting hole are in interference fit.

[0055] The material and shape of the magnetic isolation portion 41 and the thermal insulation portion 42 will be described in detail below.

[0056] The material of the magnetic isolation portion 41 is a magnetic conductor, and the thermal insulation portion 42 is a thermal insulator. Preferably, the magnetic isolation portion 41 is a circular plate made of 45# steel, and the thermal insulation portion 42 is a plastic thermal insulation block arranged on the circular plate. The magnetic isolation portion 41 made of 45# steel has good shielding effect on the alternating magnetic field generated during the operation of the motor. Since the plastic material is a poor conductor of heat, its thermal conductivity is much smaller than that of metal material. Therefore, the thermal insulation portion 42 made of plastic material can effectively prevent the heat generated by the motor from being transmitted to the magneto-electric encoder 3. It should be noted that the magnetic isolation portion 41 (i.e. the circular plate made of 45# steel) in the embodiment of the present application is easy to process and has low assembly requirements. It can effectively shield the influence of external alternating magnetic field on the magneto-electric encoder 3 while greatly reducing the manufacturing cost of the motor.

[0057] Finally, the overall working principle of the motor in the embodiment of the present application will be described. Before introducing the overall working principle of the motor, the internal elements of the motor will be described in detail. Figure 1As shown, first, the motor in the embodiment of the application is a servo motor, of course, in some alternative embodiments, the motor can also be a stepper motor installed with a magneto-encoder, in the embodiment of the application, the specific form of the motor is not limited, wherein the motor housing 1 includes a shell 11 with an opening and an end cover 12 arranged at the opening of the shell 11, the above-mentioned protection structure is installed at the end cover 12, wherein the above-mentioned motor winding 2 includes a rotating shaft 21 arranged in the motor housing 1 and a front bearing 22, a stator 23, a rear bearing 24 and a brake 25 arranged along the axis of the rotating shaft 21 in sequence, wherein the rotating shaft 21 has a first axial end and a second axial end, the end cover 21 is arranged away from the first axial end, the protection structure 2 is fixedly installed on the surface of the end cover 12, the magneto-encoder 3 is provided with a carbon steel shaft sleeve 31, the magnetically isolated part 41 is provided with an axial hole, and the second axial end of the rotating shaft 21 is connected to the carbon steel shaft sleeve through the axial hole.

[0058] When the motor is working, the stator 23 is connected to alternating current, and the alternating magnetic field generated thereby interacts with the rotor core magnetic field, thereby driving the rotating shaft 21 to rotate and work, the magneto-encoder 3 at the end of the rotating shaft 21 detects the motor speed and angle information, and feeds back these information to the servo drive controller, thereby realizing precise control of the servo motor. The brake 25 inside the motor generates an alternating magnetic field when the motor is running, in the embodiment of the application, the magnetically isolated part 42 (i.e. the circular magnetically isolated plate) arranged between the magneto-encoder 3 and the end cover 12 can have a good shielding effect on the alternating magnetic field generated by the brake 25, and because the servo motor has heat loss such as iron loss and copper loss, therefore, the motor generates a lot of heat when running for a long time, which is transmitted through the end cover 12, the rotating shaft 21 and the magneto-encoder 3 part, in the embodiment of the application, the heat insulation part 42 (i.e. the heat insulation block) made of plastic material can effectively insulate the heat generated by the motor from being transmitted to the magneto-encoder 3.

[0059] Compared with the traditional motor, the motor in the embodiment of the application changes the mounting mode of the magneto-encoder 3 and the end cover 12, and changes the direct assembly of the magneto-encoder 3 on the end cover. The alternating magnetic field generated by the motor brake 25 is shielded by the magnetic isolation part 41 arranged on the end cover 12, and then the heat insulation part 42 (i.e. the heat insulation block) is arranged between the magneto-encoder 3 and the magnetic isolation part 41, which can increase the axial distance between the magneto-encoder 3 and the end cover 12, the magneto-encoder 3 and the heat insulation part 42 only have a small area of contact, the heat conduction contact area with the magnetic isolation part 41 (i.e. the circular magnetic isolation plate made of 45# steel) is reduced, and the bottom of the magneto-encoder 3 is in a suspended state, which is beneficial to heat dissipation, effectively reduces the heat generated by the motor and the brake 25 itself during operation to the magneto-encoder 3, thereby reducing the temperature of the magneto-encoder 3 during operation, and the design power density of the motor is not limited to the upper limit of the temperature rise of the magneto-encoder 3, which ensures the stable and safe operation of the motor. In summary, through the above settings, the influence of external alternating magnetic field and heat on the magneto-encoder 3 can be reduced, thereby achieving the purpose of protecting the magneto-encoder 3 and ensuring the accuracy of motor speed, torque and position control.

[0060] The above only describes the preferred embodiments of the application and does not limit the application in any form. Although the application has been disclosed as above, it is not intended to limit the application. Any person skilled in the art can make some changes or modifications to the above-mentioned technical content without departing from the scope of the technical solution of the application, and any simple modification, equivalent change and modification of the above-mentioned embodiments according to the technical essence of the application are still within the scope of the application.

Claims

1. An electric machine characterized in that, The motor comprises a shell (1) and a motor winding (2) and a magneto-encoder (3) outside the shell (1) arranged in the shell (1) respectively; The motor further comprises a protection structure (4) arranged between the motor winding (2) and the magneto-encoder (3), and the protection structure (4) is configured to protect the magneto-encoder (3); The protection structure comprises a magnetic isolation part (41) and a heat insulation part (42); The magnetic isolation part (41) is configured to shield the alternating magnetic field generated by the motor winding (2) from being transmitted to the magneto-encoder (3) to provide a first protection for the magneto-encoder (3), and the heat insulation part (42) is configured to block the heat generated by the motor winding (2) from being transmitted to the magneto-encoder (3) to provide a second protection for the magneto-encoder (3); The protection structure (4) is mounted outside the shell (1), the magnetic isolation part (41) in the protection structure (4) is connected with the shell (1), and the heat insulation part (42) in the protection structure (4) is connected with the magneto-encoder (3); The heat insulation part (42) is mounted on the magnetic isolation part (41), and a side of the heat insulation part (42) connected with the magneto-encoder (3) protrudes from the magnetic isolation part (41) to leave a gap between the magneto-encoder (3) and the magnetic isolation part (41); A first mounting hole is formed through the magnetic isolation part (41), the heat insulation part (42) is embedded in the first mounting hole and at least partially protrudes out of the first mounting hole, and a second mounting hole is formed through the heat insulation part (42) and communicates with the first mounting hole; A third mounting hole is formed through the magneto-encoder (3), and the magneto-encoder (3) is mounted on the heat insulation part (42) through a long-shaft screw and mounted on the shell (1) through the heat insulation part (42) and the magnetic isolation part (41).

2. The electric machine of claim 1, wherein, A groove is formed in the shell (1) for embedding the heat insulation part (42), and the heat insulation part (42) is embedded in the groove and fixedly connected with the shell (1).

3. The electric machine of claim 2, wherein, The magnetic isolation part (41) is detachably connected with the shell (1), or a screw hole is formed in the magnetic isolation part (41), the magnetic isolation part (41) is mounted on the shell (1) through a screw, or the magnetic isolation part (41) is connected with the shell (1) through glue, or the magnetic isolation part (41) is integrally formed with the shell (1).

4. The electric machine of claim 3, wherein, The first mounting hole is a stepped hole, and the long-shaft screw is made of stainless steel.

5. The electric machine of claim 4, wherein, The magnetic isolation part (41) is made of a magnetic conductor, and the heat insulation part (42) is a thermal insulator.

6. The electric machine of claim 5, wherein, The magnetic isolation part (41) is a circular plate made of 45# steel, and the heat insulation part (42) is a plastic heat insulation block arranged on the circular plate.

7. The electric machine of claim 5 or 6, characterized in that The shell (1) comprises a shell body (11) with an opening and an end cover (12) arranged on the opening of the shell body (11); The motor winding (2) comprises a rotating shaft (21) and a front bearing (22), a stator (23), a rear bearing (24) and a brake (25) arranged along an axis of the rotating shaft (21) in sequence; The rotating shaft (21) has a first axial end and a second axial end, the end cover (21) is arranged away from the first axial end, and the protection structure (2) is fixedly installed on the surface of the end cover (12); The magnetic electric encoder (3) is internally provided with a carbon steel shaft sleeve (31), the shaft hole (411) is penetrated and arranged on the magnetic isolation part (41), and the second axial end of the rotating shaft (21) is connected to the carbon steel shaft sleeve through the shaft hole (411).

8. The electric machine according to any one of claims 1-6, wherein the electric machine is a servo motor.

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