A mechanical multi-turn absolute encoder and joint reduction motor

Abstract

The present invention relates to the field of multi-turn encoders and motors, and discloses a mechanical multi-turn absolute value encoder and a joint reduction motor using the encoder. The encoder comprises a stator, a rotor, and a bearing. The stator comprises a housing; a gear module comprising a transition gear set and a counting gear set; a PCB board comprising a PCB substrate, an excitation drive module, a position resolution module, a magnetic sensor, interface terminals, and a coil; the rotor comprises an input gear; and a code disk comprising a code disk substrate and a copper foil code track. The mechanical multi-turn absolute value encoder provided by the present invention solves the problems of existing joint reduction motor encoders, such as large axial dimensions, low resolution accuracy, and difficulty adapting to oil contamination. It also facilitates iterative upgrades and serialization of encoders.

Description

Technical Field

[0001] The present invention relates to the field of multi-turn encoders and motors, and in particular to a mechanical multi-turn absolute value encoder and a joint reduction motor using the encoder. Background Art

[0002] In the field of articulated reduction motors, encoders are crucial for accurately providing feedback on the motor's rotor angle and position. However, existing encoders suffer from numerous drawbacks in practical applications. While magnetic induction encoders are well-established for high-speed applications, their extended magnetic head and magnetic sensing chip at the end of the shaft not only increase the axial size but also hinder the accuracy required for accurate resolution in articulated robots. While photoelectric encoders meet high-precision requirements, they must be located at the end of the shaft, occupying axial space and failing to operate properly in oily environments. The addition of a sealed cavity increases cost, complexity, and size. While emerging inductive hollow encoders address the axial thickness issue, they can only detect absolute angle within a single turn. Adding a magnet to achieve multi-turn counting increases rotor size, shortens the life of bearings and gears, and requires additional axial installation space. Furthermore, the encoder installation process is complex and requires extensive motor modifications, resulting in high overall modification costs. These shortcomings severely restrict the application of articulated reduction motors in high-precision, compact applications, necessitating a new solution that overcomes the bottlenecks of existing technologies. Summary of the Invention

[0003] In response to the above problems, the present invention provides a mechanical multi-turn absolute encoder and a joint reduction motor, which are used to solve the problems commonly existing in the encoders used in joint reduction motors in the prior art, such as large axial size, poor solution accuracy, and difficulty in adapting to oily environments. In addition, the encoder installation process is complicated and the modification of the motor is large, resulting in high overall modification costs.

[0004] In a first aspect, the present invention discloses a mechanical multi-turn absolute encoder, comprising a stator, a rotor and a bearing, characterized in that the stator comprises: a housing, a mounting hole and a plurality of positioning holes are provided on the top of the housing, and a wire groove is provided on the outer wall of the housing; a gear module, fixed in the positioning hole on the top of the housing through one end of a gear shaft, the gear module comprising a transition gear group and a counting gear group, wherein the transition gear group and the counting gear group are engaged to transmit speed, the counting gear group is composed of an N-stage reduction gear group and a permanent magnet, and a permanent magnet is provided on the driven gear of each stage of the N-stage reduction gear group, where N is a natural number greater than or equal to 1; a PCB board, fixed to the Inside the shell, the PCB board includes a PCB substrate, an excitation drive module, a position resolution module, a magnetic sensor, an interface terminal and a coil; wherein the magnetic sensor is arranged on the upper surface of the PCB substrate and is parallel to the permanent magnet to induce magnetic field changes, the interface terminal is arranged at the wire groove of the shell, and the coil is arranged on the lower surface of the PCB substrate; the rotor includes: an input gear, which is engaged with the transition gear set for speed transmission, and a rotor mounting hole is provided on the input gear; a code disk, which is parallel to the PCB board and includes a code disk substrate and a copper foil code track; a bearing, which is arranged between the input gear and the shell and is mechanically fixed to the shell.

[0005] Preferably, it further comprises a rotor support, wherein the lower end platform of the rotor support is bonded to the code disc, and the upper end is fixed to the input gear by screws.

[0006] Preferably, the stator profile circumference is smaller than two-thirds of a circle.

[0007] Preferably, the reduction gear set is a small-module duplex gear set, with the gears arranged in layers in the axial direction and staggered inwards and outwards in the radial direction.

[0008] Preferably, the other end of the gear shaft of the transition gear set is also fixed on the PCB substrate of the PCB board to achieve double-end fixation.

[0009] Preferably, the counting gear set is composed of a 3-stage reduction gear set and 3 permanent magnets, the transmission ratio of the reduction gear set is 16:1, and the maximum number of counting turns of the counting gear set is 4095 turns.

[0010] Preferably, the transition gear set includes two sets of gears meshing with each other and having transmission ratios of 1:2.5 and 2.5:1.

[0011] Preferably, the magnetic sensitive device is one of a magnetic induction chip, a Hall element, ANR, TMR, and GMR.

[0012] Preferably, the coil includes an excitation coil and an induction coil, and the induction coil is directly opposite to the copper foil code track.

[0013] In the second aspect, the present invention discloses a joint reduction motor, including a rotor motor and a mechanical multi-turn absolute encoder as described in any of the above items; the rotor motor includes a motor body, a motor drive plate and a motor end cover; the mechanical multi-turn absolute encoder is fixed to the motor body and electrically connected to the motor drive plate through a cable, and the motor end cover is fixed and pressed onto the rotor motor body by screws.

[0014] Compared with the existing technology, the mechanical multi-turn absolute value encoder provided by the present invention can meet the requirements of anti-pollution, small axial space, and single and multi-turn high-precision detection. The stator contour circumference of the inductive sensor does not exceed two-thirds of the circle and does not occupy the space of the entire circle. While being able to fully record the absolute position of the rotor angle, it not only makes room for the motor drive components and multi-turn technical gear components to flexibly set the gears, but also does not limit the design of its reduction ratio due to the arrangement of the coils, which is conducive to the iterative upgrade and serialization of the encoder. It also makes room for the motor drive components, further reduces the axial size of the joint reduction motor, and makes installation simple and convenient. The shortened axial space has little effect on the wear of high-precision gears and bearings, ensuring their service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is an exploded diagram of a mechanical multi-turn absolute encoder.

[0016] Figure 2 It is another exploded diagram of a mechanical multi-turn absolute encoder.

[0017] Figure 3 It is a partial exploded diagram of a mechanical multi-turn absolute encoder.

[0018] Figure 4 This is a schematic diagram of the explosion of the reduction motor part.

[0019] Figure 5 This is a schematic diagram of the reduction motor explosion.

[0020] Description of reference numerals:

[0021] 1. Stator;

[0022] 11. Housing, 111. Positioning hole, 112. Wire trough, 113. Mounting hole, 114. Protruding shaft;

[0023] 12. Gear module, 121. Transition gear set, 122. Counting gear set, 1221. Reduction gear set, 1222. Magnet;

[0024] 13. PCB board, 131. PCB substrate, 132. magnetic induction chip, 133. interface terminal, 134. coil, 1341. excitation coil, 1342. induction coil;

[0025] 2. Rotor;

[0026] 21. Input gear, 211. Rotor mounting hole;

[0027] 22, code disk, 221, code disk substrate, 222 copper foil code channel;

[0028] 23. Rotor support;

[0029] 3. Bearings;

[0030] 41. Motor body; 42. Motor end cover;

[0031] 5. Install the screws. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below with reference to the accompanying drawings.

[0033] One embodiment of the present invention discloses a mechanical multi-turn absolute encoder, referring to Figures 1 to 3 A mechanical multi-turn absolute encoder includes a stator 1, a rotor 2, and a bearing 3. To save space and facilitate installation and layout, the stator 1 is not circular; its outer contour is only one-third of a circle. The stator includes a housing 11, a gear module 12, and a PCB 13. The rotor includes an input gear 21, a code disk 22, and a rotor support.

[0034] A mounting hole 113 and a plurality of positioning holes 111 are provided on the top of the housing 11 , a wire groove 112 is provided on the outer wall of the housing 11 , and a protruding shaft 114 is provided on the inner wall of the top.

[0035] The gear module 12 includes a transition gear set 121 and a counting gear set 122. The transition gear set 121 is used to transmit the received speed to the counting gear set 122 without distinction. The transition gear is composed of two groups of gears for acceleration and deceleration with transmission ratios of 1:2.5 and 2.5:1 respectively. The small gear with a transmission ratio of 1:2.5 is engaged with the input gear 21, and the large gear with a transmission ratio of 2.5:1 is engaged with the counting gear set 122 to transmit the speed of the input gear 21 to the counting gear set 122; the counting gear set 122 is set to 3-stage reduction, consisting of 3 groups of reduction gear sets with a transmission ratio of 16:1. A magnet 1222 is bonded to the driven wheel at the end of each stage of the reduction gear set 1221, and the magnet 1222 rotates with the reduction gear set 1221. In terms of layout, in order to minimize the radial space occupancy, the gears are axially layered and radially staggered inward and outward. This design allows the layout of the gears to overlap between different layers. One end of the gear shaft of the gear module 12 is initially fixed to the positioning hole 111 through hole-shaft matching, and then epoxy glue is injected into the positioning hole 111 to fix the gear module 12 on the housing 11 at one end.

[0036] The maximum number of counting turns of the counting gear set 122 is 4095 turns.

[0037] PCB board 13 is bonded to housing 11 with epoxy adhesive. PCB board 13 includes a PCB substrate 131 made of multiple layers of PCB. PCB substrate 131 is provided with a through-hole fixing interface (not shown). The other end of the gear shaft of transition gear set 121 is fixed in the fixing interface, achieving double-end fixation and ensuring high-speed and stable rotation of the gear. Three magnetic sensing chips 132 are welded to the upper surface of PCB substrate 131. The position and distribution of magnetic sensing chips 132 match the distribution of magnets 1222. Magnetic sensing chips 132 are parallel and aligned with magnets 1222, and are used to sense changes in the magnetic field caused by the rotation of magnets 1222. Coils 134 are drawn on the lower surface of PCB substrate 131. Coils 134 include an excitation coil 1341 and an induction coil 1342. Induction coil 1342 is drawn within the excitation range formed by excitation coil 1341. The excitation drive module, the position calculation module and the interface terminal 133 are arranged in the area outside the coil 132 drawing area and the magnetic induction chip 132 arrangement area; wherein the interface terminal 133 is set at the wire groove 112 of the housing 11.

[0038] The bearing 3 is an ultra-thin deep groove ball bearing. Since the bearing 3 itself has extremely high precision, its inner circle is mechanically fixed to the top inner wall of the housing 11 through a hole-shaft fit. The outer circle of the bearing 3 is fitted with the input gear 21.

[0039] The circumference of the rotor mounting hole 221 on the end surface of the input gear 21 is arranged on the same axis as the mounting hole 113 provided on the top of the housing 11 , and the input gear is fixed on the rotor support 23 .

[0040] The code disc 22 is bonded to the rotor support 23, and the PCB board 13 is parallel to it. The code disc 22 includes a code disc substrate 221 and a copper foil code track 222. The copper foil code track 222 is etched on the code disc substrate 221 according to a specific code value. The metal copper foil and the insulating medium are spaced apart to form a circumferential copper foil code track 222. The copper foil code track 222 is opposite to the coil 134 to generate an eddy current effect.

[0041] The embodiment of the present invention also discloses a joint reduction motor, referring to Figure 4 、 Figure 5A joint reduction motor includes a rotor motor and the aforementioned mechanical multi-turn absolute encoder. The rotor motor includes a motor body 41, a motor drive board (not shown in the figure) and a motor end cover 42; the mounting hole 113 on the rotating housing 11 is aligned with the rotor mounting hole 211 on the end face of the input gear 21, and the mechanical multi-turn absolute encoder is fixed to the motor body 41 by installing screws 5. The motor drive board is electrically connected to the PCB board 13 through a cable and an interface terminal 133, and the motor end cover 42 is fixed and pressed onto the rotor motor drive board by screws.

[0042] Since the motor body 41 , the motor drive plate and the motor end cover 42 in the technical solution are existing technologies, their structures are not described in detail here.

[0043] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A mechanical multi-turn absolute encoder, comprising a stator, a rotor and a bearing, characterized in that: The stator comprises: A housing, wherein a mounting hole and a plurality of positioning holes are provided on the top of the housing, and a wire groove is provided on the outer wall of the housing; The gear module is fixed in the positioning hole on the top of the housing through one end of the gear shaft. The gear module includes a transition gear set and a counting gear set, wherein: The transition gear set and the counting gear set are engaged to transmit speed. The counting gear set is composed of an N-stage reduction gear set and a permanent magnet. A permanent magnet is provided on the driven gear of each stage of the N-stage reduction gear set, where N is a natural number greater than or equal to 1. A PCB board is fixed in the housing, and the PCB board includes a PCB substrate, an excitation drive module, a position resolution module, a magnetic sensor, an interface terminal and a coil; wherein, The magnetic sensor is arranged on the upper surface of the PCB substrate and is parallel to the permanent magnet to sense the change of the magnetic field. The interface terminal is arranged at the wire groove of the shell. The coil is arranged on the lower surface of the PCB substrate. The rotor comprises: An input gear meshing with the transition gear set to transmit speed, the input gear being provided with a rotor mounting hole; A code disk, parallel to and facing the PCB board, including a code disk substrate and a copper foil code channel; a bearing, disposed between the input gear and the housing and mechanically fixed to the housing; The stator profile circumference is smaller than two-thirds of a circle.

2. A mechanical multi-turn absolute encoder according to claim 1, characterized in that: It also includes a rotor support, the lower end platform of the rotor support is bonded to the code disc, and the upper end is fixed to the input gear by screws.

3. The mechanical multi-turn absolute encoder according to claim 1, characterized in that: The reduction gear set is a small-module double gear, with the gears arranged in layers in the axial direction and staggered inwards and outwards in the radial direction.

4. The mechanical multi-turn absolute encoder according to claim 1, characterized in that: The other end of the gear shaft of the transition gear set is also fixed on the PCB substrate of the PCB board to achieve double-end fixation.

5. The mechanical multi-turn absolute encoder according to claim 1, characterized in that: The counting gear set is composed of a three-stage reduction gear set and three permanent magnets. The transmission ratio of the reduction gear set is 16:1, and the maximum number of counting turns of the counting gear set is 4095 turns.

6. The mechanical multi-turn absolute encoder according to claim 1, characterized in that: The transition gear set includes two sets of gears meshing with each other at transmission ratios of 1:2.5 and 2.5:

1.

7. The mechanical multi-turn absolute encoder according to claim 1, characterized in that: The magnetic sensing device is one of a magnetic sensing chip, a Hall element, ANR, TMR, and GMR.

8. The mechanical multi-turn absolute encoder according to claim 1, characterized in that: The coil includes an excitation coil and an induction coil, and the induction coil is directly opposite to the copper foil code track.

9. A joint reduction motor, characterized in that: It comprises a rotor motor and a mechanical multi-turn absolute encoder according to any one of claims 1 to 8; the rotor motor comprises a motor body, a motor drive board and a motor end cover; the mechanical multi-turn absolute encoder is fixed to the motor body and electrically connected to the motor drive board via a cable, and the motor end cover is fixed and pressed onto the rotor motor body by screws.

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