Electric machine and encoder therefor

Abstract

The application relates to an electric machine and an encoder thereof, the encoder comprising a first code disc assembly, a second code disc assembly and a photosensitive element, the first code disc assembly comprising a first shaft sleeve and a first code disc, the first shaft sleeve being sleeved on the outer periphery of a rotating shaft of the electric machine, the first code disc having a plurality of first code tracks spaced apart from each other in the circumferential direction; the second code disc assembly comprising a second shaft sleeve and a second code disc, the second shaft sleeve being sleeved on the outer periphery of the rotating shaft, the second code disc having a plurality of second code tracks spaced apart from each other in the circumferential direction; the encoder having a first state and a second state, when the rotating speed of the electric machine is less than or equal to a preset rotating speed, the encoder is switched from the first state to the second state, and the orthographic projection of the first code track on the photosensitive element and the orthographic projection of the second code track on the photosensitive element are mutually dislocated. Thus, the gap between the plurality of first code tracks and the plurality of second code tracks can be fully utilized to realize high-precision and high-resolution operation of the encoder when the rotating speed of the electric machine is less than or equal to the preset rotating speed.

Description

Technical Field

[0001] The present application relates to the technical field of encoders, and in particular to a motor and an encoder thereof. Background Art

[0002] An encoder is an angle and speed measurement device that integrates optical / magnetic, mechanical, and electrical methods. It converts optical signals into electrical signals through mechanical structures and signal processing circuits, thereby achieving direct or indirect measurement of various physical quantities such as angular displacement, position, and speed. The encoder is usually installed at the rear end of the motor.

[0003] In the prior art, machine tools require high positioning accuracy and high repeatability, especially in low-speed machining states. The motor is directly connected to the machine tool's screw for movement. If there is no reducer structure, the requirements for the motor are even higher. Therefore, it is necessary to make the encoder have high resolution and high precision. However, to improve the absolute accuracy and resolution of the encoder, it is necessary to increase the number of physical lines (code channels) of the encoder's code disk, but the number of physical lines is limited by the existing technical capabilities and process levels, and the physical accuracy of the code channels is limited; if the physical accuracy is improved, it is generally achieved by increasing the outer diameter of the code disk, but from the perspective of universality and cost, it cannot be adapted to motors of various calibers. Therefore, how to reasonably improve the accuracy and resolution of the encoder has become an urgent problem to be solved. Summary of the Invention

[0004] The present application provides an encoder for a motor to solve the problem of low accuracy and low resolution of the encoder when the motor speed is low.

[0005] In a first aspect, the present application provides an encoder for a motor.

[0006] In a second aspect, the present application provides a motor comprising the above-mentioned encoder.

[0007] According to an embodiment of the present application, the encoder of the motor includes a first code disc assembly, the first code disc assembly includes a first sleeve and a first code disc arranged on the first sleeve, the first sleeve is sleeved on the outer circumference of the rotating shaft of the motor, and the first code disc has a plurality of first code tracks spaced from each other along the circumferential direction; a second code disc assembly, the second code disc assembly includes a second sleeve and a second code disc arranged on the second sleeve, the second sleeve is sleeved on the outer circumference of the rotating shaft, and the second code disc has a plurality of second code tracks spaced from each other along the circumferential direction; a photosensitive element, the photosensitive element, the first code disc and the second code disc are arranged in sequence along the axial direction of the rotating shaft; the encoder has a first state and a second state, when the speed of the motor is less than or equal to the preset speed, the encoder switches from the first state to the second state, and the orthographic projection of the first code track on the photosensitive element and the orthographic projection of the second code track on the photosensitive element are staggered with each other.

[0008] According to an encoder for a motor in an embodiment of the present application, when the rotational speed of the motor is less than or equal to a preset rotational speed, the orthographic projection of the first code disk on the photosensitive element and the orthographic projection of the second code channel on the photosensitive element are offset from each other. This can fully utilize the gaps between multiple first code channels and multiple second code channels, thereby increasing the accuracy of the encoder's code disk, achieving high-precision operation of the motor at low speed, improving the resolution of the encoder, and having low cost and good adaptability.

[0009] In some embodiments, the encoder further includes: a first limit member, which is arranged on the side of the first sleeve away from the photosensitive element; a second limit member, which is arranged on the side of the second sleeve away from the photosensitive element. When the speed of the motor is greater than the preset speed, the encoder switches from the second state to the first state, and the first limit member is suitable for cooperating with the second limit member, and the orthographic projection of the first code channel on the photosensitive element coincides with the orthographic projection of the second code channel on the photosensitive element.

[0010] In some embodiments, the encoder further comprises: a first magnetic ring and a circuit board, wherein the circuit board is located on a side of the second code disk assembly away from the photosensitive element, and the first magnetic ring is fixed to the circuit board of the encoder and is located on an outer peripheral side of the rotating shaft;

[0011] The second code disc assembly is movable along the axial direction of the rotating shaft. The second code disc assembly also includes: a first coil, which is fixed to the end of the second sleeve away from the photosensitive element and is arranged opposite to the first magnetic ring. There is an attractive force between the first magnetic ring and the first coil.

[0012] In some embodiments, the second code disk assembly further includes: a second coil and a second magnetic ring, wherein the second magnetic ring and the second coil are both disposed at an end of the second sleeve facing the photosensitive element; the first code disk assembly further includes: a third magnetic ring, wherein the third magnetic ring is fixed to an end of the first code disk assembly away from the photosensitive element, wherein the third magnetic ring, the second magnetic ring, and the second coil are sequentially arranged in the axial direction of the rotating shaft, and an attractive force is generated between the second magnetic ring and the third magnetic ring;

[0013] When the encoder is in a first state, the attraction between the second magnetic ring and the third magnetic ring is smaller than the attraction between the first magnetic ring and the first coil; when the encoder is in a second state, the attraction between the second magnetic ring and the third magnetic ring is greater than the attraction between the first magnetic ring and the first coil.

[0014] In some embodiments, a first accommodating space and a second accommodating space are constructed in the second sleeve, the first accommodating space is located on the side of the second sleeve facing away from the photosensitive element, the first coil is fixed in the first accommodating space, the second accommodating space is located on the side of the second sleeve facing the photosensitive element, and the second coil is fixed in the second accommodating space.

[0015] In some embodiments, an epoxy resin layer is provided in each of the first accommodation space and the second accommodation space, and the epoxy resin layer surrounds the first coil and the second coil to seal the first accommodation space and the second accommodation space, respectively.

[0016] In some embodiments, at least one of the first magnetic ring, the second magnetic ring, and the third magnetic ring is a ferrite member or a neodymium iron boron member.

[0017] In some embodiments, the first limiting member includes a first annular inclined surface, and the second limiting member includes a second annular inclined surface. When the encoder is in the first state, the first annular inclined surface is suitable for cooperating with the second annular inclined surface; one of the first limiting member and the second limiting member has a first protrusion, and the other of the first limiting member and the second limiting member has a first accommodating groove, and the first protrusion is suitable for cooperating in the first accommodating groove.

[0018] In some embodiments, the side of the first sleeve facing the photosensitive element has a third annular bevel, and the side of the second sleeve facing the photosensitive element has a fourth annular bevel. When the encoder is in the second state, the third annular bevel is suitable for matching with the fourth annular bevel.

[0019] In some embodiments, the slope of the third annular bevel relative to the axial direction of the rotating shaft is the same as the slope of the fourth annular bevel relative to the axial direction of the rotating shaft; or the slope of the third annular bevel relative to the axial direction of the rotating shaft is greater than the slope of the fourth annular bevel relative to the axial direction of the rotating shaft.

[0020] In some embodiments, one of the third annular bevel and the fourth annular bevel is provided with a second protrusion, and the other of the third annular bevel and the fourth annular bevel is provided with a second receiving groove, and the second protrusion is suitable for fitting into the second receiving groove.

[0021] In some embodiments, the second sleeve is located on the outer circumference of the first sleeve, and the first sleeve and the second sleeve are slidably matched via a sliding assembly.

[0022] In some embodiments, the sliding assembly comprises a sliding rail and a sliding bearing, one of the first shaft sleeve and the second shaft sleeve is provided with the sliding rail, and the other of the first shaft sleeve and the second shaft sleeve is provided with the sliding bearing, the sliding bearing being in sliding fit with the sliding rail.

[0023] In some embodiments, the outer peripheral wall of the first shaft sleeve is formed with a mounting groove, and the sliding assembly is fitted in the mounting groove.

[0024] In some embodiments, the preset rotating speed n satisfies the relationship: 0rpm < n≤ 200rpm.

[0025] Additional aspects and advantages of the present application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings, which are incorporated herein and constitute part of the specification, illustrate embodiments consistent with the application and, together with the description, serve to explain the principles of the application.

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0028] One or more embodiments are illustrated by the drawings in the corresponding drawings, which do not constitute a limitation on the embodiments, and elements with the same reference numerals in the drawings represent similar elements, unless otherwise specified, and the drawings in the drawings do not constitute a proportional limit.

[0029] Figure 1 A cross-sectional view of an encoder is provided for the embodiments of the present application, wherein the encoder is in a first state;

[0030] Figure 2 A cross-sectional view of an encoder is provided for the embodiments of the present application, wherein the encoder is in a second state;

[0031] Figure 3 A cross-sectional view of a first code disc assembly is provided for the embodiments of the present application;

[0032] Figure 4 A cross-sectional view of a second code disc assembly is provided for the embodiments of the present application;

[0033] Figure 5 A top view of a partial structure of a first code disc is provided for the embodiments of the present application;

[0034] Figure 6 A top view of a partial structure of a second code wheel provided in an embodiment of the present application;

[0035] Figure 7 An orthographic projection of a first code channel on a photosensitive element and an orthographic projection of a second code channel on a photosensitive element provided in an embodiment of the present application, wherein the encoder is in a second state;

[0036] Figure 8 A top view of a second coil provided in an embodiment of the present application;

[0037] Figure 9 A side view of a third annular inclined surface provided in an embodiment of the present application;

[0038] Figure 10 A top view of a second protrusion and a second receiving groove provided in an embodiment of the present application.

[0039] Description of reference numerals:

[0040] 100, encoder; 200, rotating shaft;

[0041] 10. First code disk assembly; 11. First sleeve; 111. Third annular bevel; 112. Mounting groove; 113. First annular bevel; 114. First sleeve portion; 115. Second sleeve portion; 116. Slot; 117. Socket; 12. First code disk; 121. First code track; 13. Third magnetic ring;

[0042] 20. Second code disk assembly; 21. Second shaft sleeve; 211. Fourth annular inclined surface; 212. First accommodating space; 213. Second accommodating space; 214. Second annular inclined surface;

[0043] 22. Second code disk; 221. Second code track; 23. First coil; 24. Second coil; 25. Second magnetic ring;

[0044] 30. Photosensitive element; 40. Light-emitting element; 50. First magnetic ring; 60. Circuit board; 70. Sliding assembly; 71. Sliding rail; 80. Second protrusion; 90. Second receiving groove. DETAILED DESCRIPTION

[0045] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0046] The disclosure below provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, these are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0047] For ease of description, spatially relative terms may be used herein to describe the relative position or movement of one element or feature relative to another element or feature as shown in the figures, such as "inside," "outside," "above," "below," etc. Such spatially relative terms are intended to include different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures undergoes a positional flip, a change in posture, or a change in motion, the directional indications will also change accordingly. For example, an element described as "below" or "below" another element or feature will subsequently be oriented as "above" or "above" another element or feature. Thus, the example term "below" can include both above and below orientations. The device may be oriented differently (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein should be interpreted accordingly.

[0048] In order to solve the technical problems of low accuracy and low resolution of encoders during low-speed processing in the prior art, the present application provides an encoder 100 that can achieve high-precision and high-resolution operation of the encoder 100 when the motor speed is low.

[0049] Reference below Figures 1-10 The encoder 100 according to the first embodiment of the present application is described, and the encoder 100 includes: a first code wheel assembly 10, a second code wheel assembly 20, and a photosensitive element 30. In the description of the present application, "plurality" means two or more.

[0050] Specifically, if Figures 1-10As shown, the first code disk assembly 10 includes a first sleeve 11 and a first code disk 12 mounted on the first sleeve 11. The first sleeve 11 is mounted on the outer circumference of the motor's rotating shaft 200. The first code disk 12 has a plurality of first code tracks 121 spaced apart from one another along the circumferential direction. For example, the plurality of first code tracks 121 are evenly and spaced apart along the circumference of the first code disk 12. The second code disk assembly 20 includes a second sleeve 21 and a second code disk 22 mounted on the second sleeve 21. The second sleeve 21 is mounted on the outer circumference of the rotating shaft 200. The second sleeve 21 can be mounted directly or indirectly on the outer circumference of the rotating shaft 200. For example, the first sleeve 11 is mounted on the outer circumference of the rotating shaft 200, and the second sleeve 21 is mounted on the outer circumference of the first sleeve 11. Both the first sleeve 11 and the second sleeve 21 rotate with the rotating shaft 200. The second code disk 22 has a plurality of second code tracks 221 spaced apart from one another along the circumferential direction. For example, the plurality of second code tracks 221 are evenly and spaced apart in the circumferential direction of the second code wheel 22. For example, the first code track 121 and the second code track 221 are made of opaque material, and the first code wheel body and the second code wheel body are made of opaque material, but are not limited thereto.

[0051] The photosensitive element 30 , the first code disk 12 , and the second code disk 22 are sequentially arranged along the axial direction of the rotating shaft 200 . The encoder 100 may further include a light emitting element 40 , which is disposed on a side of the second code disk 22 away from the photosensitive element 30 .

[0052] The encoder 100 has a first state and a second state. When the motor speed is less than or equal to a preset speed, the encoder 100 switches from the first state to the second state. When the encoder 100 is in the second state, the orthographic projection of the first code track 121 on the photosensitive element 30 and the orthographic projection of the second code track 221 on the photosensitive element 30 are offset from each other. In other words, the orthographic projection of the first code wheel 12 on the photosensitive element 30 and the orthographic projection of the second code track 221 on the photosensitive element 30 are arranged alternately. In this case, the gaps between the multiple first code tracks 121 and the multiple second code tracks 221 can be fully utilized to increase the total number of working code tracks, thereby improving the physical accuracy of the encoder 100.

[0053] It is understood that the motor's rotating shaft 200 can drive the first and second code discs 12 and 22 to rotate. The light sensor 30 on the circuit board can convert the light transmittance of the code tracks of the operating code discs into varying electrical signals. By recording the electrical signals, the position and speed of the rotating shaft 200 can be recorded. When the first and second code discs 12 and 22 are operating, they rotate along with the motor's rotating shaft 200.

[0054] When the speed of the motor is less than or equal to the preset speed, the motor is in a low-speed rotation state, and the first code disk 12 and the second code disk 22 are both working. Since the orthographic projections of the multiple first code channels 121 of the first code disk 12 and the multiple second code channels 221 of the second code disk 22 on the photosensitive element 30 are staggered, the light emitted by the light-emitting component 40 can pass through the first code channels 121 and the second code channels 221. The actual light transmittance is the light transmittance of the first code channels 121 and the light transmittance of the second code channels 221, thereby achieving high-precision and high-resolution operation at a low speed of the motor.

[0055] According to the encoder 100 of the motor of the embodiment of the present application, when the rotational speed of the motor is less than or equal to the preset rotational speed, the orthographic projection of the first code disk 12 on the photosensitive element 30 and the orthographic projection of the second code channel 221 on the photosensitive element 30 are offset from each other, and the gaps between the multiple first code channels 121 and the multiple second code channels 221 can be fully utilized to increase the accuracy of the code disk of the encoder 100, realize high-precision operation of the motor at low speed, improve the resolution of the encoder 100, and have low cost and good adaptability.

[0056] In some embodiments, the encoder 100 includes a first stopper and a second stopper. The first stopper is disposed on the first sleeve 11, and the second stopper is disposed on the second sleeve 21. When the motor speed exceeds a preset speed, the encoder 100 switches from the second state to the first state. The first stopper is adapted to cooperate with the second stopper, so that the orthographic projection of the first code track 121 on the photosensitive element 30 coincides with the orthographic projection of the second code track 221 on the photosensitive element 30. The provision of the first and second stoppers ensures synchronous rotation of the first and second code discs 12 and 22, so that the orthographic projections of the first and second code tracks 121 and 221 on the photosensitive element 30 remain coincident. As the motor speed changes, the encoder 100 can switch between the first and second states, achieving adaptive encoder 100. It is understood that the second state of the encoder 100 is a high-precision state.

[0057] When the speed of the motor is greater than the preset speed, the motor is in a high-speed rotation state. The photosensitive element in the prior art will be limited by the linear speed of the code disk, which will affect the ability to collect light data. Therefore, when the motor is running at high speed, the signal frequency is too high, and the photosensitive element often needs to be customized. The disadvantages of customization are high price, long cycle, non-universal materials, and physical precision cannot be guaranteed. Even if the code disk is made using high-precision technology, when running at high speed, the photosensitive element will cause a shutdown due to the exponential increase in the sampling frequency. Therefore, in an embodiment of the present application, when in a high-speed state, the orthographic projection of the first code channel 121 on the photosensitive element 30 coincides with the orthographic projection of the second code channel 221 on the photosensitive element 30. Therefore, the setting of the second code disk 22 at this time will not increase the total number of working code channels, thereby preventing the photosensitive element 30 from shutting down, thereby increasing the service life of the photosensitive element 30.

[0058] like Figure 1 and Figure 2 As shown, the encoder 100 further includes a first magnetic ring 50 and a circuit board 60. The circuit board 60 is located on the side of the second code disk assembly 20 away from the photosensitive element 30. The first magnetic ring 50 is fixed to the circuit board 60 of the encoder 100 and is located on the outer peripheral side of the rotating shaft 200. It is understandable that the first magnetic ring 50 does not rotate with the rotation of the rotating shaft 200. The second code disk assembly 20 is along the axial direction of the rotating shaft 200 (for example, Figure 1 and Figure 2 The second code disk assembly 20 further includes a first coil 23, which is fixed to the end of the second sleeve 21 away from the photosensitive element 30 and is disposed opposite the first magnetic ring 50. An attractive force exists between the first magnetic ring 50 and the first coil 23. Thus, under the attractive force between the first magnetic ring 50 and the first coil 23, the second code disk assembly 20 can move toward the first magnetic ring 50. This allows the first and second position limiting members to cooperate with each other to ensure the stability of the overlap between the orthographic projection of the first code track 121 on the photosensitive element 30 and the orthographic projection of the second code track 221 on the photosensitive element 30.

[0059] Further, refer to Figure 1 and Figure 2The second code disc assembly 20 further comprises a second coil 24 and a second magnetic ring 25, both of which are arranged at an end of the second shaft sleeve 21 facing the photosensitive element 30. The first code disc assembly 10 further comprises a third magnetic ring 13 fixed at an end of the first code disc assembly 10 away from the photosensitive element 30. In the axial direction of the rotating shaft 200, the third magnetic ring 13, the second magnetic ring 25 and the second coil 24 are arranged in sequence, and the second magnetic ring 25 has an attractive force with the third magnetic ring 13. When the encoder 100 is in the first state, the rotating speed of the motor is greater than the preset rotating speed, the attractive force between the second magnetic ring 25 and the third magnetic ring 13 is smaller than the attractive force between the first magnetic ring 50 and the first coil 23, and the second code disc assembly 20 can move towards the first coil 23 until the first limiting part and the second limiting part limit each other to make the normal projection of the first code track 121 on the photosensitive element 30 coincide with the normal projection of the second code track 221 on the photosensitive element 30.

[0060] When the encoder 100 is in the second state, the rotating speed of the motor is less than or equal to the preset rotating speed, and the attractive force between the second magnetic ring 25 and the third magnetic ring 13 is greater than the attractive force between the first magnetic ring 50 and the first coil 23. That is, when the rotating speed of the motor changes from high speed to low speed, the second code disc assembly 20 can move towards the third magnetic ring 13 under the action of the attractive force between the second magnetic ring 25 and the third magnetic ring 13, and the normal projection of the first code track 121 on the photosensitive element 30 and the normal projection of the second code track 221 on the photosensitive element 30 are misaligned with each other, so that the gap between the code tracks can be used to improve the accuracy of the encoder 100 when running at low speed.

[0061] It can be understood that the relationship between the normal projections of the first code track 121 and the second code track 221 on the photosensitive element 30 can be switched according to the actual rotating speed of the motor by the driving assembly. In the example as shown in FIG. 1, Figure 1-Figure 2 the relationship between the normal projections of the first code track 121 and the second code track 221 on the photosensitive element 30 can be switched according to the actual rotating speed of the motor by the cooperation of the first coil 23, the second coil 24, the first magnetic ring 50, the second magnetic ring 25 and the third magnetic ring 13 of the driving assembly. Of course, in other examples, the switching can be realized by a crank slider or other structure of the driving assembly.

[0062] In some embodiments, as Figure 4As shown, a first accommodating space 212 and a second accommodating space 213 are constructed in the second sleeve 21. The first accommodating space 212 is located on the side of the second sleeve 21 facing away from the photosensitive element 30. The first coil 23 is fixed in the first accommodating space 212. The second accommodating space 213 is located on the side of the second sleeve 21 facing the photosensitive element 30. The second coil 24 is fixed in the second accommodating space 213. The first accommodating space 212 and the second accommodating space 213 can respectively provide magnetic fields for the first coil 23 and the second coil 24 to cooperate with the first magnetic ring 50 and the third magnetic ring 13 to drive the second code disk assembly 20 to move along the axial direction of the motor shaft 200. At the same time, it can provide installation positions for the first coil 23 and the second coil 24, ensuring the installation stability and operating stability of the first coil 23 and the second coil 24, thereby ensuring the operating stability of the encoder 100.

[0063] Furthermore, an epoxy resin layer is provided within both the first and second accommodating spaces 212, 213. The epoxy resin layer surrounds the first and second coils 23, 24 to seal the first and second accommodating spaces 212, 213. Epoxy resin has excellent insulating properties, ensuring the stability of the magnetic field generated by the first and second coils 23, 24. It also has high adhesion and provides a good sealing effect.

[0064] For example, at least one of the first magnetic ring 50, the second magnetic ring 25, and the third magnetic ring 13 is a ferrite or a neodymium iron boron. For example, the first magnetic ring 50, the second magnetic ring 25, and the third magnetic ring 13 can all be ferrite or neodymium iron boron. Ferrite or neodymium iron boron parts have good magnetic properties and can further cooperate with the first magnetic ring 50 and the third magnetic ring 13 to drive the second code disk assembly 20 to move along the axial direction of the motor's rotating shaft 200 to control the relationship between the positive projections of the first code channel 121 and the second code channel 221 on the photosensitive element 30, thereby improving the adaptability of the encoder 100. Of course, the first coil 23 and the second coil 24 can be wound in a group of four, but this does not represent a limitation to this. The materials of the first magnetic ring 50, the second magnetic ring 25, and the third magnetic ring 13 can be flexibly selected according to actual needs to make the encoder 100 more applicable.

[0065] In some embodiments, as Figure 1 and Figure 2As shown, the first stopper includes a first annular bevel 113, and the second stopper includes a second annular bevel 214. When the encoder 100 is in the first state, the first annular bevel 113 is adapted to cooperate with the second annular bevel 214. One of the first stopper and the second stopper has a first protrusion (not shown), and the other of the first stopper and the second stopper has a first receiving groove (not shown). The first protrusion is adapted to fit within the first receiving groove. Thus, after the second code disk assembly 20 moves toward the first magnetic ring 50, the first annular bevel 113 and the second annular bevel 214 cooperate with each other to generate a tangential force, so that the first protrusion can fit within the first receiving groove, so that the orthographic projections of the first code track 121 and the second code track 221 on the photosensitive element 30 can remain in an overlapping state.

[0066] In some embodiments, as Figure 3 、 Figure 4 as well as Figure 9 As shown, the first sleeve 11 has a third annular bevel 111 on the side facing the photosensitive element 30, and the second sleeve 21 has a fourth annular bevel 211 on the side facing the photosensitive element 30. When the encoder 100 is in the second state, the third annular bevel 111 is suitable for cooperating with the fourth annular bevel 211. It can be understood that the cross-sections of the third annular bevel 111 and the fourth annular bevel 211 in the radial direction of the rotating shaft 200 are annular. When the rotating shaft 200 of the motor switches from a high speed to a low speed, the second code disc assembly 20 is suitable for moving toward the direction of the photosensitive element 30, and when the third annular bevel 111 and the fourth annular bevel 211 cooperate with each other to stop, a tangential force can be generated to rotate the second code disc assembly 20 in the circumferential direction and to cause the positive projection of the first code disc 12 on the photosensitive element 30 and the positive projection of the second code channel 221 on the photosensitive element 30 to be misaligned with each other, forming a tangential force as shown in FIG. Figure 7 The orthographic projection is shown to achieve high-precision operation of the motor at low speeds.

[0067] When the third annular bevel 111 and the fourth annular bevel 211 cooperate with each other, the action force between the third annular bevel 111 and the fourth annular bevel 211 will provide a tangential force to drive the second code disc assembly 20 to rotate along the circumferential direction of the rotating shaft 200 to ensure that the first code disc 12 and the second code disc 22 are both working and the orthographic projection of the first code disc 12 on the photosensitive element 30 and the orthographic projection of the second code channel 221 on the photosensitive element 30 are staggered with each other, thereby increasing the number of code channels during low-speed rotation to improve the accuracy of the encoder 100.

[0068] Furthermore, one of the third annular inclined surface 111 and the fourth annular inclined surface 211 has a second protrusion 80, and the other of the third annular inclined surface 111 and the fourth annular inclined surface 211 has a second receiving groove 90. The second protrusion 80 is adapted to fit within the second receiving groove 90, thereby enabling the orthographic projection of the first code disk 12 on the photosensitive element 30 and the orthographic projection of the second code track 221 on the photosensitive element 30 to be offset from each other. Thus, the relative positions of the first code disk 12 and the second code disk 22 in the circumferential direction can be limited to ensure that the second protrusion 80 fits within the second receiving groove 90, thereby enabling the orthographic projection of the first code disk 12 on the photosensitive element 30 and the orthographic projection of the second code track 221 on the photosensitive element 30 to be offset from each other, thereby improving the operating stability of the encoder 100 at low motor speeds.

[0069] In some embodiments, the inclination of the third annular bevel 111 relative to the axial direction of the rotating shaft 200 is the same as the inclination of the fourth annular bevel 211 relative to the axial direction of the rotating shaft 200; or the inclination of the third annular bevel 111 relative to the axial direction of the rotating shaft 200 is greater than the inclination of the fourth annular bevel 211 relative to the axial direction of the rotating shaft 200. Both of these configurations can ensure that the third annular bevel 111 and the fourth annular bevel 211 cooperate firmly with each other, ensuring that the first code wheel assembly 10 and the second code wheel assembly 20 can rotate synchronously, thereby achieving high-precision setting of the low speed of the motor.

[0070] In some embodiments, the second sleeve 21 is located on the outer periphery of the first sleeve 11, and the first sleeve 11 and the second sleeve 21 are slidably engaged via a sliding assembly 70. The provision of the sliding assembly 70 facilitates the movement of the second code disk assembly 20 relative to the first code disk assembly 10, and the second code disk assembly 20 can be driven to move without excessively high magnetic fields or changes in attractive forces, and the movement is smooth, thereby improving the stability of the encoder 100.

[0071] In some examples, the sliding assembly 70 includes a slide rail 71 and a sliding bearing (not shown). The slide rail 71 is provided on one of the first sleeve 11 and the second sleeve 21, and the sliding bearing is provided on the other of the second sleeve 21 and the first sleeve 11. The sliding bearing slides in cooperation with the slide rail 71. For example, the slide rail 71 is provided on the first sleeve 11, and the sliding bearing is provided on the second sleeve 21 so that the sliding bearing slides in cooperation with the slide rail 71. The sliding assembly 70 thus configured slides more smoothly and stably, further improving the stability of the encoder 100. Of course, in other embodiments, the sliding assembly 70 can also be a combination of a slider and a slide rail 71, a combination of a slide rail 71 and a pulley, etc., which are not limited here.

[0072] In some embodiments, the outer peripheral wall of the first shaft sleeve 11 is formed with a mounting groove 112, and the sliding assembly 70 is fitted in the mounting groove 112. In this way, on the one hand, the mounting reliability of the sliding assembly 70 can be improved, and on the other hand, the occupied space can be reduced, which is conducive to the miniaturization design of the encoder 100. For example, the side wall of the mounting groove 112 facing the third annular slope 111 is connected with the third annular slope 111, so as to further improve the smoothness of the sliding of the second code disc assembly 20, facilitate the cooperation between the third annular slope 111 and the fourth annular slope 211, and ensure the stability of the cooperation between the third annular slope 111 and the fourth annular slope 211. For example, as shown in Figure 1 and Figure 3 The first shaft sleeve 11 can include a first shaft sleeve part 114 and a second shaft sleeve part 115, the first shaft sleeve part 114 is located on the side of the second shaft sleeve part 115 facing the photosensitive element 30, the first shaft sleeve part 114 is interference-fitted with the second shaft sleeve part 115, the mounting groove 112 can be formed on the second shaft sleeve part 115, the second shaft sleeve part 115 has a slot 116 in one of the first shaft sleeve parts 114, the second shaft sleeve part 115 has a socket 117 in the other of the first shaft sleeve parts 114, the socket 117 is plug-fitted with the slot 116, so as to facilitate positioning, and meanwhile, the cooperation between the first shaft sleeve part 114 and the second shaft sleeve part 115 can be more stable.

[0073] In some embodiments, the preset rotating speed n satisfies the relationship: 0rpm < n≤ 200rpm. For example, the preset rotating speed n can be 0rpm < n≤ 100rpm. The preset rotating speed n can be 100rpm, or can be 50rpm. When the preset rotating speed n is within the above range, the rotating speed of the motor is lower, which can make the encoder 100 have higher precision and better applicability.

[0074] The operation principle of the encoder 100 of the embodiments of the present application will be described below in combination with Figures 1-10

[0075] ​When the motor is running at low speed, the first code disc assembly 10 and the second code disc assembly 20 can run synchronously. When the motor enters the high-speed state from the low-speed state (for example, the motor speed in the high-speed state is 100rpm-8000rpm), the second code disc assembly 20 and the first code disc assembly 10 initially rotate together, wherein the first coil 23 of the second code disc assembly 20 cuts the magnetic field of the first magnetic ring 50 to generate an induced current, and further generates an induced magnetic field in the second accommodating space 213 of the second sleeve 21. The magnetic field offsets the magnetic force of the second magnetic ring 25, and at the same time, generates a downward attraction to attract the first magnetic ring 50; at this time, the attraction between the first magnetic ring 50 and the first coil 23 is greater than the second magnetic ring 50. Due to the attraction between the third magnetic ring 13 and the second magnetic ring 25, the second code disk assembly 20 moves downward until the first annular inclined surface 113 cooperates with the second annular inclined surface 214. The first protrusion and the first accommodating groove cooperate with each other to limit the relative position of the first code disk 12 and the second code disk 22 in the circumferential direction. At this time, the second coil 24 begins to cut the magnetic field of the third magnetic ring 13 to offset the magnetic field of the second magnetic ring 25; the first code disk assembly 10 and the second code disk assembly 20 rotate synchronously with the rotating shaft 200, and the orthographic projections of the first code channel 121 and the second code channel 221 on the photosensitive element 30 can remain overlapping.

[0076] When the motor enters low-speed operation from a high-speed state (for example, the motor speed in the low-speed state is 0-100rpm), the second coil 24 cuts the magnetic field of the third magnetic ring 13. Affected by the speed, the induced current decreases, and the induced electromotive force decreases, so it cannot offset the magnetic field of the second magnetic ring 25. The second magnetic ring 25 and the third magnetic ring 13 are attracted by the magnetic field. At this time, the attraction between the first magnetic ring 50 and the first coil 23 is less than the attraction between the third magnetic ring 13 and the second magnetic ring 25. The second code disk assembly 20 moves upward until the third annular inclined surface 111 of the first shaft sleeve 11 and the fourth annular inclined surface 211 of the second shaft sleeve 21 cooperate with each other and cause the second code disk assembly 20 to rotate relative to the first code disk assembly 10 in the circumferential direction until the second protrusion 80 and the second accommodating groove 90 cooperate with each other to limit the relative positions of the first code disk assembly 10 and the second code disk assembly 20 in the circumferential direction, so that the code channels of the first code disk 12 and the second code disk 22 are formed as follows. Figure 7 The staggered structure shown makes full use of the gap and increases the code disk accuracy of the encoder 100. At this time, the first code disk assembly 10 and the second code disk assembly 20 rotate synchronously. The photosensitive element 30 and the like generate an electrical signal through the combination of the first code disk 12 and the second code disk 22.

[0077] According to an embodiment of the second aspect of the present application, the motor includes the encoder 100 described in the above embodiment. According to the motor of the embodiment of the present application, when the rotational speed of the motor is less than or equal to the preset rotational speed, the orthographic projection of the first code disk 12 on the photosensitive element 30 and the orthographic projection of the second code track 221 on the photosensitive element 30 are misaligned with each other, which can fully utilize the gaps between the multiple first code tracks 121 and the multiple second code tracks 221, increase the accuracy of the code disk of the encoder 100, achieve high-precision operation of the motor at low speed, improve the resolution of the encoder 100, and have low cost and good adaptability.

[0078] The stator core, brake and other components and operations of the motor according to the embodiment of the present application are well known to those skilled in the art and will not be described in detail here.

[0079] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0080] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0081] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. An encoder for a motor, characterized in that: include: a first code disc assembly, the first code disc assembly comprising a first sleeve and a first code disc disposed on the first sleeve, the first sleeve being sleeved on an outer circumference of a rotating shaft of the motor, the first code disc having a plurality of first code tracks spaced apart from each other along a circumferential direction; a second code disc assembly, the second code disc assembly comprising a second sleeve and a second code disc disposed on the second sleeve, the second sleeve being sleeved on the outer circumference of the rotating shaft, the second code disc having a plurality of second code tracks spaced apart from each other along a circumferential direction; A photosensitive element, wherein the photosensitive element, the first code disk, and the second code disk are sequentially arranged along the axial direction of the rotating shaft; The encoder has a first state and a second state. When the speed of the motor is less than or equal to a preset speed, the encoder switches from the first state to the second state, and the orthographic projection of the first code channel on the photosensitive element and the orthographic projection of the second code channel on the photosensitive element are offset from each other.

2. The motor encoder according to claim 1, characterized in that: Also includes: a first limiting member, the first limiting member being arranged on a side of the first sleeve away from the photosensitive element; The second limit member is arranged on the side of the second sleeve away from the photosensitive element. When the speed of the motor is greater than the preset speed, the encoder switches from the second state to the first state. The first limit member is suitable for cooperating with the second limit member. The orthographic projection of the first code channel on the photosensitive element coincides with the orthographic projection of the second code channel on the photosensitive element.

3. The motor encoder according to claim 2, characterized in that: The encoder further includes: a first magnetic ring and a circuit board, wherein the circuit board is located on a side of the second code disk assembly away from the photosensitive element, and the first magnetic ring is fixed to the circuit board of the encoder and is located on the outer circumference of the rotating shaft; The second code disc assembly is movable along the axial direction of the rotating shaft, and the second code disc assembly further comprises: The first coil is fixed to an end of the second sleeve away from the photosensitive element and is arranged opposite to the first magnetic ring. There is an attractive force between the first magnetic ring and the first coil.

4. The motor encoder according to claim 3, characterized in that: The second code disc assembly further includes: a second coil and a second magnetic ring, wherein the second magnetic ring and the second coil are both provided at an end of the second sleeve facing the photosensitive element; The first code disk assembly further includes: a third magnetic ring, the third magnetic ring being fixed to an end of the first code disk assembly away from the photosensitive element, wherein the third magnetic ring, the second magnetic ring, and the second coil are arranged in sequence in the axial direction of the rotating shaft, and an attractive force is generated between the second magnetic ring and the third magnetic ring; When the encoder is in the first state, the attraction between the second magnetic ring and the third magnetic ring is smaller than the attraction between the first magnetic ring and the first coil; when the encoder is in the second state, the attraction between the second magnetic ring and the third magnetic ring is greater than the attraction between the first magnetic ring and the first coil.

5. The motor encoder according to claim 4, characterized in that: A first accommodating space and a second accommodating space are constructed in the second sleeve. The first accommodating space is located on the side of the second sleeve facing away from the photosensitive element, and the first coil is fixed in the first accommodating space. The second accommodating space is located on the side of the second sleeve facing the photosensitive element, and the second coil is fixed in the second accommodating space.

6. The motor encoder according to claim 5, characterized in that: An epoxy resin layer is provided in each of the first accommodation space and the second accommodation space. The epoxy resin layer surrounds the first coil and the second coil to seal the first accommodation space and the second accommodation space respectively.

7. The motor encoder according to claim 4, characterized in that: At least one of the first magnetic ring, the second magnetic ring and the third magnetic ring is a ferrite component or a neodymium iron boron component.

8. The motor encoder according to claim 7, characterized in that: The first limiting member includes a first annular inclined surface, and the second limiting member includes a second annular inclined surface. When the encoder is in the first state, the first annular inclined surface is suitable for matching with the second annular inclined surface. One of the first limiting member and the second limiting member has a first protrusion, and the other of the first limiting member and the second limiting member has a first receiving groove, and the first protrusion is suitable for fitting into the first receiving groove.

9. The motor encoder according to claim 1, characterized in that: The first sleeve has a third annular bevel on its side facing the photosensitive element, and the second sleeve has a fourth annular bevel on its side facing the photosensitive element. When the encoder is in the second state, the third annular bevel is suitable for matching with the fourth annular bevel.

10. The motor encoder according to claim 9, characterized in that: The inclination of the third annular inclined surface relative to the axial direction of the rotating shaft is the same as the inclination of the fourth annular inclined surface relative to the axial direction of the rotating shaft; or The inclination of the third annular inclined surface relative to the axial direction of the rotating shaft is greater than the inclination of the fourth annular inclined surface relative to the axial direction of the rotating shaft.

11. The motor encoder according to claim 9, characterized in that: One of the third annular slope and the fourth annular slope is provided with a second protrusion, and the other of the third annular slope and the fourth annular slope is provided with a second receiving groove, and the second protrusion is suitable for fitting into the second receiving groove.

12. The motor encoder according to claim 9, characterized in that: The second shaft sleeve is located on the outer circumference of the first shaft sleeve, and the first shaft sleeve and the second shaft sleeve are slidably matched through a sliding assembly.

13. The motor encoder according to claim 12, characterized in that: The sliding assembly includes a sliding rail and a sliding bearing. The sliding rail is provided on one of the first shaft sleeve and the second shaft sleeve, and the sliding bearing is provided on the other of the second shaft sleeve and the first shaft sleeve. The sliding bearing is in sliding engagement with the sliding rail.

14. The motor encoder according to claim 12, characterized in that: An installation groove is formed on the outer peripheral wall of the first sleeve, and the sliding assembly is fitted in the installation groove.

15. The motor encoder according to claim 1, characterized in that: The preset rotation speed n satisfies the relationship: 0 rpm < n ≤ 200 rpm.

16. A motor, characterized in that: Comprising an encoder according to any one of claims 1-15.

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