A dynamic testing device for strain of high-speed built-in permanent magnet rotor

Abstract

The application discloses a kind of high-speed built-in permanent magnet rotor strain dynamic testing device, including driving system, testing system and electric signal acquisition processing system;Driving system includes high-speed prime mover and elastic diaphragm coupling;High-speed prime mover can be through acceleration and deceleration to make it rotate stably at different rotational speed;Testing system includes high-speed slip ring device, built-in permanent magnet rotor core, strain gauge and power supply device, built-in permanent magnet rotor core is connected with the rotor of high-speed slip ring device by spline, strain gauge is pasted at the magnetic bridge of the built-in permanent magnet rotor core, elastic diaphragm coupling one end connects the rotating shaft of high-speed prime mover, the other end connects the high-speed slip ring device.The application has the characteristics of short testing cycle and high testing precision, and can obtain the change rule of permanent magnet rotor mechanical strength with rotational speed and structural parameters, to provide an effective measurement means for accurately evaluating the strength performance of permanent magnet rotor and verifying the reliability of permanent magnet rotor strength design.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electric machines, in particular to a dynamic testing device for strain of a high-speed built-in permanent magnet rotor. BACKGROUND

[0002] The high-speed built-in permanent magnet synchronous motor has the advantages of high power density, high efficiency, miniaturization, wide speed regulation range and excellent overload capacity. Therefore, it has wide application prospects in the fields of high-speed wear-resistant machine tools, air circulation refrigeration systems, energy storage flywheels and fuel cells. When the high-speed built-in permanent magnet rotor rotates at high speed, the rotor magnetic bridge needs to withstand the huge centrifugal force caused by the pole shoe and the permanent magnet, and the magnetic bridge structure is relatively weak, so the rotor structural integrity is easily damaged. Therefore, accurately measuring the mechanical strain of the built-in rotor structure and ensuring that the rotor strength meets the requirements are of great significance to the safe and reliable operation of the high-speed built-in permanent magnet synchronous motor.

[0003] Currently, there are mainly three methods to test the strength of the built-in permanent magnet rotor. The first method is reliability testing, which determines whether the rotor meets the design requirements by observing whether the prototype can run normally for a long time when rotating at high speed. The second method is plastic deformation observation, which evaluates the rotor strength by observing whether plastic deformation occurs after the built-in permanent magnet rotor core sample runs at different speeds. The third method is static equivalent experiment, which evaluates the rotor strength by observing whether plastic deformation occurs in the built-in permanent magnet rotor when a pulling force equal to the centrifugal force is applied to the auxiliary bridge of a pair of magnetic poles. The first method has a long test cycle, and the first two methods cannot reflect the change law of the rotor structural strength with the speed and structural parameters in the elastic deformation stage. The third method cannot accurately reflect the change law of the rotor core mechanical strength with the speed and structural parameters in the dynamic condition.

[0004] It can be seen that the above-mentioned schemes cannot accurately determine the change law of the rotor dynamic strength with the speed and structural parameters. The most effective method for directly testing the rotor strength is to measure the stress of the rotor structure. At present, there is a lack of a dynamic testing device for the mechanical stress of the high-speed built-in permanent magnet rotor. SUMMARY

[0005] The purpose solved by the application is to provide a dynamic testing device for strain of a high-speed built-in permanent magnet rotor, which dynamically measures the strain at the magnetic bridge of the high-speed built-in permanent magnet rotor and obtains the change law of the mechanical strength of the permanent magnet rotor with the speed and structural parameters, thereby providing an effective measurement means for accurately evaluating the strength performance of the permanent magnet rotor and verifying the reliability of the strength design of the built-in permanent magnet rotor.

[0006] In order to achieve the above-mentioned purpose, the application provides a dynamic testing device for strain of a high-speed built-in permanent magnet rotor, which adopts the technical scheme as follows:

[0007] A kind of high-speed built-in permanent magnet rotor strain dynamic testing device, including driving system, testing system and electric signal acquisition processing system;

[0008] The driving system includes high-speed prime mover and elastic diaphragm coupling;High-speed prime mover can be accelerated or decelerated to make it rotate stably at different speeds;

[0009] The testing system includes high-speed slip ring device, built-in permanent magnet rotor core, strain gauge and power supply device, the high-speed slip ring device includes multiple brushes and multiple slip rings, the built-in permanent magnet rotor core is connected with the rotor of high-speed slip ring device by spline, the strain gauge is pasted at the magnetic bridge of the built-in permanent magnet rotor core, the elastic diaphragm coupling is connected with the rotating shaft of high-speed prime mover at one end, and is connected with the high-speed slip ring device at the other end;

[0010] Single magnetic bridge strain test electric signal transmission route is: power supply device→first brush→first slip ring→strain gauge→second slip ring→second brush→electric signal acquisition processing system.

[0011] Further, the power supply device, the first brush, the first slip ring and the strain gauge, the strain gauge and the second slip ring / second brush and the electric signal acquisition processing system transmit electric signal through lead wire, the first brush and the first slip ring, the second slip ring and the second brush transmit electric signal through friction contact.

[0012] Further, the high-speed slip ring device includes stator, rotor, bearing snap ring and bearing, the rotor is connected with the stator by bearing;

[0013] The stator includes upper end cover, lower end cover, upper end cover support, brush support, sheath and brush, the upper end cover is connected with the lower end cover by upper end cover support, the brush support is connected with the lower end cover by nut;

[0014] The rotor includes slip ring rotor rotating shaft and slip ring, the slip ring is fixed on the slip ring rotor rotating shaft and rotates synchronously with the slip ring rotor rotating shaft.

[0015] Further, the upper end cover is provided with first through hole, first bearing positioning hole, lead hole and rotation stop piece, the first through hole and first bearing positioning hole are provided with multiple,

[0016] The rotation stop piece is used to prevent the lower end cover from rotating;

[0017] The lead hole is used to realize the lead connection between power supply device and brush, electric signal acquisition processing system and brush,

[0018] The first bearing positioning hole is used to realize the radial and axial positioning of bearing;

[0019] The nut passes through the first through hole to connect the upper end cover support, the brush support and the lower end cover.

[0020] Further, the upper end cover support is provided with threaded holes at two ends, and the threaded holes are used in cooperation with threaded assemblies to fix the axial distance between the upper end cover and the lower end cover.

[0021] Further, the brush support is provided with the brush through threaded assembly, so that the brush and the slip ring are in friction contact to transmit the electric signal.

[0022] Further, the lower end cover is provided with a second through hole and a second bearing positioning hole corresponding to the first through hole and the first bearing positioning hole provided on the upper end cover.

[0023] Further, the upper end of the slip ring rotor shaft is provided with a plurality of radial lead holes, an axial lead hole, a plurality of bearing snap ring grooves, a plurality of slip ring grooves, an embedded permanent magnet rotor core shaft shoulder and a plurality of splines.

[0024] The slip ring groove is used for axial positioning of the slip ring.

[0025] The bearing snap ring groove is used for axial positioning of the slip ring rotor shaft.

[0026] The axial lead hole is used for leading out the lead wire connected with the strain gauge and the slip ring.

[0027] The embedded permanent magnet rotor core shaft shoulder is used for axial positioning of the core.

[0028] The spline is used for circumferential positioning of the slip ring rotor shaft, the elastic diaphragm coupling and the permanent magnet rotor core.

[0029] Further, the thickness of the slip ring is less than the depth of the slip ring groove.

[0030] Further, the radius of the embedded permanent magnet rotor core shaft shoulder is less than the radius of the position of the magnetic bridge of the embedded permanent magnet rotor core.

[0031] The beneficial effects of the present application are:

[0032] The present application uses the method of dynamic friction contact to solve the problem of leading out the lead wire of the strain gauge pasted on the magnetic bridge of the high-speed rotating rotor, fully considers the structural features of the embedded permanent magnet rotor core, designs a reasonable dynamic strain testing device, and realizes the dynamic measurement function of the strain of the high-speed permanent magnet rotor core. The testing device has the characteristics of simple structure, low cost, short testing period and high testing precision, and can obtain the change rule of the mechanical strength of the permanent magnet rotor with the rotation speed and the structural parameters, and provides an effective measurement method for accurately evaluating the strength performance of the permanent magnet rotor and verifying the reliability of the strength design of the permanent magnet rotor. Attached Figure Description

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0034] Figure 1 A schematic diagram of the test principle of a dynamic testing device for strain of a high-speed built-in permanent magnet rotor according to an embodiment of the present invention is shown.

[0035] Figure 2 An assembly diagram of the drive system and the test system of a dynamic testing device for strain of a high-speed built-in permanent magnet rotor according to an embodiment of the present invention is shown, but the sheath is not shown in the diagram.

[0036] Figure 3 A schematic diagram of the assembly of a high-speed slip ring device according to an embodiment of the present invention is shown, wherein (a) is a top view and (b) is a cross-sectional view AA;

[0037] Figure 4 A schematic diagram of the lower end cover according to an embodiment of the present invention is shown, (a) is a front view, (b) is a left view, and (c) is a BB cross-sectional view. In the front view, the hole near the center is a brush bracket through hole, the right side of the hole is a lead wire hole, the other three are through holes for mounting the upper end cover bracket, and the radial hole is a bearing positioning hole.

[0038] Figure 5 The diagram shows a schematic of the upper end cap bracket according to an embodiment of the present invention, (a) being a front view and (b) being a CC cross-sectional view;

[0039] Figure 6 A schematic diagram of a brush holder according to an embodiment of the present invention is shown, (a) being a bottom view, (b) a front view, and (c) a DD cross-sectional view;

[0040] Figure 7 This diagram illustrates the assembly of the lower end cover, brush bracket, and upper end cover bracket according to an embodiment of the present invention.

[0041] Figure 8 A schematic diagram of the slip ring rotor shaft according to an embodiment of the present invention is shown, (a) is a front view, (b) is a left view, and (c) is an EE cross-sectional view. The nine radial lead holes are connected to the axial lead holes, six of which are at the slip ring slots and three at the permanent magnet rotor core shoulder.

[0042] Figure 9 A schematic diagram of a slip ring according to an embodiment of the present invention is shown, (a) being a front view and (b) a left view;

[0043] Figure 10 Fig. 1 shows a schematic diagram of an upper end cover according to an embodiment of the present application, (a) is a front view, (b) is a left view, (c) is a F-F sectional view, the axial hole is a through hole for installing an upper end cover bracket, and the radial hole is a bearing positioning hole;

[0044] Figure 11 Fig. 4 shows a schematic diagram of a strain gauge installation position according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] The above and other advantages and effects of the present application will become readily apparent to those of ordinary skill in the art from the description set forth below and the accompanying drawings. The present application can be applied or implemented in other different embodiments, and the details in the description can be modified or changed based on different views and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0046] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more; the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like is based on the orientation or positional relationship shown in the drawings, and 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. In addition, the terms "first", "second", "third" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0047] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0048] The specific embodiments of the present application are described in detail below with reference to the accompanying drawings and embodiments.

[0049] Because of the structure and size limit, the built-in permanent magnet rotor magnetic bridge is the position of the maximum strain, so it is the most easily damaged, so only need to measure the built-in permanent magnet rotor magnetic bridge strain. The basic principle of rotor strain test: high-speed prime mover (such as pneumatic motor, high-speed motor, etc.) is connected with high-speed slip ring rotor shaft through elastic diaphragm coupling, the built-in permanent magnet rotor core is connected to the slip ring rotor shaft through spline, so that the built-in permanent magnet rotor core and high-speed slip ring rotor shaft rotate synchronously with the high-speed prime mover, the power supply device is connected with the brush on the slip ring stator, and then the brush is connected with the slip ring to provide power for the strain gauge through the friction contact, the strain gauge attached to the built-in permanent magnet rotor core magnetic bridge transmits the strain information to the electric signal acquisition and processing system in the form of electric signal through the lead, so as to realize the dynamic measurement of the high-speed built-in permanent magnet rotor magnetic bridge strain.

[0050] On this basis, the embodiment of the application provides a kind of dynamic testing device of high-speed built-in permanent magnet rotor strain, by Figure 1 It is known that the dynamic testing device of high-speed built-in permanent magnet rotor strain includes driving system, test system, electric signal acquisition and processing system, wherein the driving system and test system assembly schematic diagram are as Figure 2 As shown.

[0051] The driving system includes high-speed prime mover 1 and elastic diaphragm coupling 2. High-speed prime mover can be accelerated or decelerated to make it rotate stably at different speeds; one end of elastic diaphragm coupling 2 is connected with high-speed prime mover shaft, and the other end is connected with high-speed slip ring device.

[0052] The test system includes high-speed slip ring device, built-in permanent magnet rotor core 5, strain gauge 6 and power supply device. The built-in permanent magnet rotor core 5 rotates synchronously with the high-speed slip ring rotor part through spline, and the strain gauge 6 is attached to the magnetic bridge of the built-in permanent magnet rotor core 5. The electric signal transmission route of single magnetic bridge strain test is: power supply device→first brush→first slip ring→strain gauge→second slip ring→second brush→electric signal acquisition and processing system (here, the description of first and second only represents that the first brush / slip ring and the second brush / slip ring are not the same slip ring or brush), the power supply device and the brush, the slip ring and the strain gauge, the brush and the electric signal acquisition and processing system transmit electric signal through lead, and the brush and the slip ring transmit electric signal through friction contact.

[0053] The assembly structure diagram of high-speed slip ring device is as Figure 3The high-speed slip ring device includes a rotor, a stator, a bearing snap ring 3 and a bearing 15. The rotor part mainly includes a slip ring rotor shaft 13, a slip ring 8, and the pin part mainly includes an upper end cover 4, a lower end cover 9, an upper end cover support 7, a brush support 11, a sheath 14, and a brush 12. The slip ring 8 is fixed on the slip ring rotor shaft 13 and rotates synchronously with the slip ring rotor shaft 13. The rotor and the stator are connected through the bearing 15. The upper end cover 4 and the lower end cover 9 are connected through the upper end cover support 7. The brush support 11 is connected with the lower end cover 9 through a nut.

[0054] The schematic view of the lower end cover 9 is shown in Fig. 4. Figure 4 As shown in Fig. 4, the lower end cover 9 is provided with three through holes, three bearing positioning holes, a lead hole and a rotation stopping piece 10. The rotation stopping piece 10 prevents the lower end cover from rotating. The lead hole is used to connect the lead wires between the power supply device and the brush and between the data acquisition and processing system and the brush. The bearing positioning hole is used to position the bearing in the radial and axial directions. The nut passes through the through hole to connect the upper end cover support, the brush support and the lower end cover.

[0055] The schematic view of the upper end cover support 7 is shown in Fig. 5. Figure 5 As shown in Fig. 5, the upper end cover support 7 is provided with threaded holes at both ends, which are used to fix the axial distance between the upper end cover and the lower end cover.

[0056] The schematic view of the brush support 11 is shown in Fig. 6. Figure 6 As shown in Fig. 6, the brush support 11 is provided with threaded holes. The brush support is used to fix the brush by means of threads, so that the brush 12 keeps in friction contact with the slip ring 8 to transmit the electric signal. The assembly schematic view of the lower end cover 9, the upper end cover support 7 and the brush support 11 is shown in Fig. 7. Figure 7

[0057] The schematic view of the slip ring rotor shaft 13 is shown in Fig. 8. Figure 8 As shown in Fig. 8, the slip ring rotor shaft 13 is provided with nine radial lead holes, one axial lead hole, three bearing snap ring grooves, six slip ring grooves, one built-in permanent magnet rotor iron core shaft shoulder and two splines. The slip ring groove is used to position the slip ring in the axial direction. The bearing snap ring groove is used to position the slip ring rotor shaft in the axial direction. The lead hole is used to lead out the lead wire connected with the strain gauge and the slip ring. The built-in permanent magnet rotor iron core shaft shoulder is used to position the iron core in the axial direction. The spline is used to position the slip ring rotor shaft, the elastic diaphragm coupling and the permanent magnet rotor iron core in the circumferential direction.

[0058] The schematic view of the slip ring 8 is shown in Fig. 9. Figure 9 As shown in Fig. 9, the thickness of the slip ring 8 is less than the depth of the slip ring groove of the high-speed slip ring rotor shaft.

[0059] The schematic view of the upper end cover 4 is shown in Fig. 10. Figure 10 As shown in Fig. 10, the upper end cover 4 is provided with three through holes and three bearing positioning holes.

[0060] ​Strain gauges are attached to the built-in permanent magnet rotor core gap bridge to measure the strain, and the attachment diagram is shown in Figure 11

[0061] The notes of the test process are as follows:

[0062] (1) The elastic diaphragm coupling is connected to the high-speed prime mover and the slip ring rotor shaft, and the shaft concentricity should be ensured.

[0063] (2) The selection of the strain gauge attachment position should meet the following conditions: first, the region where the maximum strain of the permanent magnet rotor gap bridge structure is generated; second, the region where the strain gauge is easily attached. Therefore, for the typical V-shaped built-in rotor structure, it is recommended that the strain gauge be attached to the central gap bridge region. Third, in order to ensure that the entire rotating tool assembly has good symmetry and reduce the initial imbalance of the assembly, the attachment regions of the strain gauges should be symmetrically distributed in the circumferential direction of the rotor core, and the connected leads should also be symmetrically distributed.

[0064] (3) The built-in permanent magnet rotor core shaft shoulder radius of the slip ring rotor shaft should be smaller than the radius of the position where the built-in permanent magnet rotor core gap bridge is located, in order to facilitate the arrangement of the strain gauges.

[0065] The above embodiments are only used to illustrate the present application, and are not limited to the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, therefore all equivalent technical solutions also belong to the scope of the present application, and the patent protection scope of the present application should be defined by the claims.​

Claims

1. A dynamic testing device for strain of a high-speed built-in permanent magnet rotor, characterized in that, This includes a drive system, a testing system, and an electrical signal acquisition and processing system; The drive system includes a high-speed prime mover and a flexible diaphragm coupling; the high-speed prime mover can be accelerated or decelerated to make it rotate stably at different speeds. The testing system includes a high-speed slip ring device, an internal permanent magnet rotor core, strain gauges, and a power supply device. The high-speed slip ring device includes multiple brushes and multiple slip rings. The internal permanent magnet rotor core is connected to the rotor of the high-speed slip ring device via a spline. The strain gauges are attached to the magnetic isolation bridge of the internal permanent magnet rotor core. One end of the elastic diaphragm coupling is connected to the shaft of the high-speed prime mover, and the other end is connected to the high-speed slip ring device. The electrical signal transmission route for a single magnetic bridge strain test is as follows: power supply device → first brush → first slip ring → strain gauge → second slip ring → second brush → electrical signal acquisition and processing system; The high-speed slip ring device includes a stator, a rotor, a bearing retainer, and a bearing, wherein the rotor and the stator are connected by the bearing; The stator includes an upper end cover, a lower end cover, an upper end cover bracket, a brush bracket, a sheath, and brushes. The upper end cover and the lower end cover are connected by the upper end cover bracket, and the brush bracket and the lower end cover are connected by nuts. The rotor includes a slip ring rotor shaft and a slip ring, wherein the slip ring is fixed on the slip ring rotor shaft and rotates synchronously with the slip ring rotor shaft; The upper end of the slip ring rotor shaft is provided with multiple radial lead holes, one axial lead hole, multiple bearing retainer grooves, multiple slip ring grooves, a built-in permanent magnet rotor core shoulder, and multiple splines. The slip ring groove is used to achieve axial positioning of the slip ring; The bearing retaining ring groove is used to achieve axial positioning of the slip ring rotor shaft; The axial lead hole is used to bring out the lead wires that are connected to the strain gauge and slip ring. The built-in permanent magnet rotor core shoulder is used to achieve axial positioning of the core. The spline is used to achieve circumferential positioning of the slip ring rotor shaft, the elastic diaphragm coupling, and the permanent magnet rotor core.

2. The dynamic testing device for high-speed built-in permanent magnet rotor strain as described in claim 1, characterized in that, The power supply device transmits electrical signals with the first brush, the first slip ring and the strain gauge, the strain gauge and the second slip ring, and the second brush and the electrical signal acquisition and processing system through lead wires. The first brush and the first slip ring, and the second slip ring and the second brush transmit electrical signals through frictional contact.

3. The dynamic testing device for high-speed built-in permanent magnet rotor strain as described in claim 1, characterized in that, The lower end cover is provided with a first through hole, a first bearing positioning hole, a lead wire hole, and an anti-rotation plate. Multiple first through holes and first bearing positioning holes are provided. The anti-rotation plate is used to prevent the lower end cover from rotating. The lead hole is used to realize the lead connection between the power supply device and the brush, and between the electrical signal acquisition and processing system and the brush. The first bearing positioning hole is used to achieve radial and axial positioning of the bearing; The nut passes through the first through hole to connect the upper end cover bracket, the brush bracket, and the lower end cover.

4. The dynamic testing device for high-speed built-in permanent magnet rotor strain as described in claim 1, characterized in that, The upper end cover bracket has threaded holes at both ends, which are used to fix the axial distance between the upper end cover and the lower end cover by engaging with the threaded assembly.

5. The dynamic testing device for high-speed built-in permanent magnet rotor strain as described in claim 1, characterized in that, The brush is threadedly mounted on the brush holder so that the brush and the slip ring maintain frictional contact to transmit electrical signals.

6. The dynamic testing device for high-speed built-in permanent magnet rotor strain as described in claim 3, characterized in that, The lower end cover is provided with a second through hole and a second bearing positioning hole, which correspond to the first through hole and the first bearing positioning hole provided on the upper end cover.

7. The dynamic testing device for high-speed built-in permanent magnet rotor strain as described in claim 1, characterized in that, The thickness of the slip ring is less than the depth of the slip ring groove.

8. The dynamic testing device for high-speed built-in permanent magnet rotor strain as described in claim 1, characterized in that, The radius of the shoulder of the built-in permanent magnet rotor core is smaller than the radius of the location of the magnetic isolation bridge of the built-in permanent magnet rotor core.

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