Mechanical multi-ring absolute value encoder and joint gear motor

Abstract

The invention relates to the field of multi-ring encoders and motors, and discloses a mechanical multi-ring absolute value encoder and a joint gear motor using the same, the encoder comprises a stator, a rotor and a bearing, the stator comprises: a housing; the gear module comprises a transition gear set and a counting gear set; the PCB comprises a PCB substrate, an excitation driving module, a position resolving module, a magnetic sensitive device, an interface terminal and a coil; the rotor includes an input gear; and the code disc comprises a code disc substrate and a copper foil code channel. Based on the mechanical multi-circle absolute value coding provided by the invention, the problems that the encoder of the existing joint gear motor is large in axial size, low in calculation precision, difficult to adapt to oil stains and the like are solved, and meanwhile, iterative upgrading and serialization of the encoder are also facilitated.

Description

Technical Field

[0001] The 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 joint reduction motors, encoders are crucial for accurate feedback of the motor rotor angle and position. However, existing encoders have many defects in practical applications. Although magnetic induction encoders are mature in high-speed applications, the magnetic head and magnetic induction chip protruding from the end of the shaft not only increase the axial size, but also the resolution accuracy is difficult to meet the high-precision requirements of joint robots. Although photoelectric encoders can meet high-precision requirements, they need to be arranged at the protruding end of the shaft, which not only occupies axial space, but also cannot work normally in an oily environment. The addition of a sealed cavity increases the cost and difficulty as well as the size difficulty. Although the emerging inductive hollow encoder can solve the axial thickness problem, it can only detect the absolute angle of a single turn. Adding magnets to achieve multi-turn counting will increase the rotor size, shorten the service life of bearings and gears, and require additional axial installation space. In addition, the encoder installation process is complicated, and the modification of the motor is large, resulting in high overall modification costs. These shortcomings seriously restrict the application of joint reduction motors in high-precision and compact scenarios, and a new solution is urgently needed to break through the bottleneck of existing technologies. Summary of the invention

[0003] In view of 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 of 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, wherein the stator comprises: a housing, a mounting hole and a plurality of positioning holes are arranged on the top of the housing, and a wire groove is arranged 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 meshed 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 arranged on the driven gear of each stage of the N-stage reduction gear group, and N is a natural number greater than or equal to 1; a PCB board, fixed to the In 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 arranged 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 channel; 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 of the rotor support is fixed to the input gear by screws.

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

[0007] Preferably, the reduction gear set is a small-module double gear, and the gears are axially layered and radially staggered inwardly and outwardly.

[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 prior art, the mechanical multi-turn absolute encoder provided by the present invention can meet the requirements of anti-pollution, small axial space, and single-turn 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 motor drive components and multi-turn technical gear components to flexibly set gears, but also does not limit the design of its reduction ratio due to the arrangement of the coil, which is conducive to the iterative upgrade and serialization of the encoder. It also makes room for 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 a schematic diagram of the explosion 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 partial explosion diagram of the reduction motor.

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

[0020] Description of reference numerals: 1. Stator; 11. housing, 111. positioning hole, 112. wire groove, 113. mounting hole, 114. convex shaft; 12. gear module, 121. transition gear set, 122. counting gear set, 1221. reduction gear set, 1222. magnet; 13. PCB board, 131. PCB substrate, 132. magnetic induction chip, 133. interface terminal, 134. coil, 1341. excitation coil, 1342. induction coil; 2. Rotor; 21. input gear, 211. rotor mounting hole; 22. Code disk, 221. Code disk substrate, 222. Copper foil track; 23. Rotor support; 3. Bearing; 41. Motor body; 42. Motor end cover; 5. Mounting screw. Detailed implementation manner

[0021] The present invention will be further described in detail below with reference to the accompanying drawings.

[0022] An embodiment of the present invention discloses a mechanical multi-turn absolute encoder. Refer to Figures 1 to 3 , a mechanical multi-turn absolute encoder includes a stator 1, a rotor 2 and a bearing 3. In order to save space and facilitate installation and layout, the stator 1 of the mechanical multi-turn absolute encoder is not set to be circular, and its outer contour is only one-third of a circle. The stator includes a housing 11, a gear module 12, and a PCB board 13. The rotor includes an input gear 21, a code disk 22 and a rotor support.

[0023] The top of the housing 11 is provided with a mounting hole 113 and a plurality of positioning holes 111. The outer wall of the housing 11 is provided with a wire groove 112, and the inner wall of the top is provided with a convex shaft 114.

[0024] 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 without difference to the counting gear set 122. The transition gear is composed of two sets of gears with transmission ratios of 1:2.5 and 2.5:1 for acceleration and deceleration respectively. Among them, the small gear with a transmission ratio of 1:2.5 meshes with the input gear 21, and the large gear with a transmission ratio of 2.5:1 meshes 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 have a three-stage deceleration and is composed of 3 sets of reduction gear sets with a transmission ratio of 16:1. A magnet 1222 is bonded to the end driven wheel of each stage of the reduction gear set 1221. The magnet 1222 rotates with the reduction gear set 1221. In the layout of the gear module 12, in order to minimize the radial space occupation, the gears are axially stratified and radially staggered. This design allows the layout of the gears to overlap between different layers. One end of the gear shaft of the gear module 12 and the positioning hole 111 are initially fixed by hole-shaft fit, and then epoxy glue is injected into the positioning hole 111 to fix the gear module 12 to the housing 11 at one end.

[0025] Among them, the maximum counting number of turns of the counting gear set 122 is 4095 turns.

[0026] The PCB board 13 is bonded to the housing 11 by epoxy adhesive. The PCB board 13 includes a PCB substrate 131 made of a multi-layer PCB. A through-going fixed interface (not shown in the figure) is provided on the PCB substrate 131. The other end of the gear shaft of the transition gear set 121 is fixed in the fixed interface to achieve double-end fixation, thereby ensuring that the gear can rotate stably at high speed. Three magnetic induction chips 132 are welded on the upper surface of the PCB substrate 131. The position distribution of the magnetic induction chips 132 matches the distribution of the magnets 1222. The magnetic induction chips 132 are parallel to and face the magnets 1222, and are used to sense the magnetic field changes caused by the rotation of the magnets 1222. A coil 134 is drawn on the lower surface of the PCB substrate 131. The coil 134 includes an excitation coil 1341 and an induction coil 1342, wherein the induction coil 1342 is drawn in the excitation interval formed by the excitation coil 1341. An excitation driving module, a position solving module and an interface terminal 133 are arranged in an area other than the coil 132 drawing area and the magnetic induction chip 132 arrangement area; wherein the interface terminal 133 is arranged at the wire slot 112 of the housing 11 .

[0027] The bearing 3 is an ultra-thin deep groove ball bearing. Since the bearing 3 has extremely high precision, its inner circle is mechanically fixed to the top inner wall of the housing 11 with a convex shaft 114 through hole-shaft matching, and the outer circle of the bearing 3 matches the input gear 21.

[0028] 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 arranged on the top of the housing 11 , and the input gear is fixed on the rotor support 23 .

[0029] The code disc 22 is bonded to the rotor support 23, and the PCB board 13 is parallel and opposite. 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 arranged at intervals to form a circumferential copper foil code track 222. The copper foil code track 222 is opposite to the coil 134 for generating an eddy current effect.

[0030] The embodiment of the present invention also discloses a joint reduction motor, referring to Figure 4 , Figure 5 A joint reduction motor comprises a rotor motor and the aforementioned mechanical multi-turn absolute encoder, the rotor motor comprises 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, the mechanical multi-turn absolute encoder is fixed to the motor body 41 by means of mounting screws 5, the motor drive board is electrically connected to the PCB board 13 through cables and interface terminals 133, and the motor end cover 42 is fixed and pressed onto the rotor motor drive board by screws.

[0031] 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.

[0032] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope 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 arranged on the top of the housing, and a wire groove is arranged on the outer wall of the housing; The gear module is fixed in the positioning hole at 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 meshed to transmit speed, the counting gear set is composed of an N-stage reduction gear set and a permanent magnet, and a permanent magnet is arranged 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 meshes with the transition gear set to transmit speed, and a rotor mounting hole is provided on the input gear; A code disc, parallel to and facing the PCB board, comprising a code disc substrate and a copper foil code channel; The bearing is disposed between the input gear and the housing and is mechanically fixed to the housing.

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 of the rotor support is fixed to the input gear by screws.

3. A mechanical multi-turn absolute encoder according to claim 1, characterized in that: The stator profile circumference is smaller than two-thirds of a circle.

4. The mechanical multi-turn absolute encoder according to claim 1, characterized in that: The reduction gear set is a small-module double gear, and the gears are axially layered and radially staggered.

5. 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.

6. The mechanical multi-turn absolute encoder according to claim 1, characterized in that: 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.

7. 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.

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

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

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

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