CN114193507A

CN114193507A - Encoder module for rotary joint, robot arm and robot

Info

Publication number: CN114193507A
Application number: CN202111654607.8A
Authority: CN
Inventors: 宋庭科; 安然; 王轩; 陈柏彦
Original assignee: Flexiv Robotics Ltd
Current assignee: Flexiv Robotics Ltd
Priority date: 2021-12-30
Filing date: 2021-12-30
Publication date: 2022-03-18

Abstract

Disclosed are an encoder module for a rotary joint, a robot arm and a robot. An encoder module is mounted in a revolute joint comprising a drive arrangement having radially spaced inner and outer shafts, the encoder module comprising: a first connecting shaft, the first end of which is connected with the tail end of the outer shaft; the first end of the second connecting shaft is fixedly connected with the inner shaft; a first disk assembly fixed to the first connecting shaft; a second disc assembly fixed to the second connecting shaft; a first sensor assembly disposed adjacent to the first disk assembly; a second sensor assembly disposed adjacent to the second disk assembly, wherein the disk surfaces of the first and second disk assemblies are coplanar and radially spaced apart by at least a predetermined distance. In the revolute joint according to this application, the encoder module not only saves articular axial space, and the clearance adjustment between sensor and the disk is convenient moreover, and the installation and the dismantlement of encoder module are efficient.

Description

Encoder module for rotary joint, robot arm and robot

Technical Field

The application relates to the field of robots, in particular to an encoder module for a rotary joint, a rotary joint with the encoder module, a robot arm with the rotary joint and a robot.

Background

In general, robots having robotic arms rely on joints to control the relative motion between the components of the robotic arms. Joints are generally divided into rotational joints and translational joints (also referred to as prismatic joints). The rotary joint can be respectively connected with the two components to rotate by utilizing a driving device so as to enable the two components to generate relative motion. In order to accurately control the movement and position of the robot arm, it is necessary to accurately measure the rotational speeds of the two output shafts of the driving device and adjust the rotational speed of each output shaft according to the measured rotational speeds.

Typically, encoders are used to measure the rotational speed of the two output shafts of the drive. An encoder is a device that converts a signal into a sine wave by magnetic or optical measurement principles. The magnetic encoder can realize a resolution as low as 1 μm, has vibration resistance, is not afraid of pollution and corrosion of dust, oil stain, water vapor, salt mist and the like, is more robust and durable than an optical encoder, and is thus widely used in the field of robots requiring precise control of a movement position.

The magnetic encoder includes a magnetic disk, a sensor, and an adjustment circuit. The magnetic disk is magnetized, and a plurality of magnetic poles are distributed on the circumference of the magnetic disk, and the polarities of the adjacent two magnetic poles are opposite. The transducer is used to detect the change in the magnetic field as the disk rotates and convert this information into a sine wave. The sensor may be a hall effect device that senses voltage changes or may be a magnetoresistive device that senses magnetic field changes. The conditioning circuitry multiplies, divides, or interpolates the signals to produce the desired output.

In a joint of a robot, two output shafts of a driving device are usually located on two sides of the driving device, and correspondingly, two sets of magnetic encoder modules are also located on two sides of the driving device respectively. Each magnetic encoder module has a magnetic disc and a PCB circuit board with a sensor chip, wherein the magnetic disc is fixed to the output shaft and the corresponding PCB circuit board is mounted to remain fixed relative to the drive device.

Disclosure of Invention

According to the first aspect of this application, provide a rotary joint's that easy to assemble and dismantle encoder module, have this encoder module structure's rotary joint and have this rotary joint's arm and robot.

In accordance with at least one embodiment of the present application, there is provided an encoder module for a revolute joint that includes a drive device having an inner shaft extending toward a same side and an outer shaft surrounding and radially spaced from the inner shaft, the encoder module comprising: a first connecting shaft having a first end and a second end, the first end of the first connecting shaft for connecting with an end of the outer shaft; the first end of the second connecting shaft is used for being fixedly connected with the inner shaft; a first disk assembly secured to the first connecting shaft; a second disc assembly fixed to the second connecting shaft; a first sensor assembly disposed adjacent to the first disk assembly; a second sensor assembly disposed adjacent to the second disk assembly, wherein the disk surfaces of the first and second disk assemblies are disposed coplanar and radially separated by at least a predetermined distance.

The encoder module may further include a bearing installed between the first connecting shaft and the second connecting shaft.

The first connecting shaft is a hollow shaft and may be formed with a first bearing positioning shoulder on an inner circumferential surface thereof, and/or the second connecting shaft may be formed with a second bearing positioning shoulder on an outer circumferential surface thereof.

A first coupling positioning shoulder may be formed on an inner circumferential surface or an outer circumferential surface of the first end of the first coupling shaft for positioning a mounting position of the first coupling shaft with respect to the outer shaft.

An additional module positioning shoulder may be formed on an outer circumferential surface of the first connecting shaft.

A second connecting positioning shoulder may be formed on an outer peripheral surface of the second connecting shaft or an end surface of the first end, for positioning a mounting position of the second connecting shaft with respect to the inner shaft.

The second connecting shaft is a hollow shaft, and a second connecting and positioning shoulder and/or a disassembly assisting shoulder can be formed on the inner peripheral surface, the second connecting and positioning shoulder is used for positioning the mounting position of the second connecting shaft relative to the inner shaft, and the disassembly assisting shoulder is used for separating the second connecting shaft from the inner shaft.

The end surface of the second end of the first connecting shaft is flush with the outer end surface of the bearing, and the end surface of the second end of the second connecting shaft is flush with the disk surface of the first disk assembly and the disk surface of the second disk assembly.

The bearing may be bonded to at least one of the first connecting shaft and the second connecting shaft by an adhesive.

The bearing can be a deep groove ball bearing, and the inner ring of the bearing can be bonded with the second connecting shaft through an adhesive.

The encoder module may further include a PCB circuit board mounting the first sensor assembly and the second sensor assembly, wherein the PCB circuit board is parallel to and spaced apart from the disk surfaces of the first disk assembly and the second disk assembly.

The first disk assembly may include a first disk and a first mounting bracket supporting the first disk, and the first mounting bracket may be mounted at the second end of the first connecting shaft.

The second disc assembly may include a second disc and a second mounting bracket supporting the second disc, and the second mounting bracket may be mounted at the second end of the second connecting shaft.

The first mounting bracket is spaced apart from the first mounting bracket both axially and radially, wherein the first mounting bracket and the first connecting shaft are separately or integrally formed, and the second mounting bracket and the second connecting shaft are separately or integrally formed.

The outer and/or inner races of the first disc may be secured to the first mounting bracket and the outer and/or inner races of the second disc may be secured to the second mounting bracket.

According to some embodiments of the present application, there is provided a revolute joint for a robot having a joint housing, the drive device, and the encoder module for a revolute joint.

The drive means may comprise a motor and a transmission driven by the motor, wherein the motor may drive one of the inner shaft and the outer shaft and the transmission may drive the other of the outer shaft and the inner shaft.

The driving device may be installed in the joint housing, and the encoder module may protrude by a predetermined length with respect to one end of the joint housing.

The revolute joint may further comprise control means for adjusting the operation of the drive means on the basis of the signals output by the first and second sensor assemblies.

According to some embodiments of the present application, there is provided a robot arm for a robot comprising at least one revolute joint for a robot as described above.

According to some embodiments of the application, there is provided a robot comprising at least one revolute joint for a robot as described above.

In the encoder module, the revolute joint, arm and the robot for revolute joint according to the embodiment of this application, the axial space of joint is not only saved to the encoder module, and the clearance adjustment convenient and fast between sensor and the disk moreover, the installation and the dismantlement of encoder module are efficient.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application. In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a partial sectional view schematically showing the structure of an encoder module in a rotary joint according to an embodiment of the present application;

FIG. 2 is a partial cross-sectional view schematically illustrating the structure and mounting of a disc assembly of an encoder module in a revolute joint according to an embodiment of the present application;

FIG. 3 is a cross-sectional view schematically illustrating a partial mounting structure of two disc assemblies of an encoder module in a revolute joint according to an embodiment of the present application;

fig. 4 is a perspective view schematically showing a combination structure of a disc assembly and a connecting shaft in an encoder module according to an embodiment of the present application.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and that modifications may be made by one skilled in the art without departing from the spirit and scope of the application and it is therefore not intended to be limited to the specific embodiments disclosed below.

Specific embodiments according to the present application will be described in detail below with reference to fig. 1 to 4.

As shown in fig. 1 to 4, a revolute joint according to one embodiment of the present application includes a drive device (not shown), a joint housing 20, and an encoder assembly 30. The drive means is fixedly mounted in a joint housing 20 which has two shafts, an outer shaft 11 and an inner shaft 12, which extend out towards the same side of the drive means and rotate about the same axis. The outer shaft 11 is a hollow shaft that surrounds and is radially spaced from the inner shaft 12. Thereby, the

inner shafts

11 and 12 rotate independently of each other.

The encoder assembly 30 includes a disc assembly and a sensor assembly, wherein the sensor assembly may be mounted on a PCB circuit board 50 and the PCB circuit board 50 may be mounted perpendicular to the axis of the output of the drive device. Specifically, the disk assembly includes a first disk assembly 31 that rotates in synchronization with the outer shaft 11 and a second disk assembly 32 that rotates in synchronization with the inner shaft 12. The sensor assembly includes a first sensor assembly for detecting a change in a magnetic field generated by the first disc assembly 31 due to rotation, and a second sensor assembly for detecting a change in a magnetic field generated by the second disc assembly 32 due to rotation.

The PCB circuit board 50 is mounted in fixed relation to the drive means, for example to the joint housing 20, by means of the connection assembly 40. In one embodiment, the PCB circuit board is installed parallel to and spaced apart from the magnetic disks of the disk assembly, for example, connected to one end of the joint housing 20 while being spaced apart from the one end of the joint housing 20 by a predetermined distance. Although the first sensor assembly and the second sensor assembly may be mounted on different circuit boards, it is advocated in this application to mount them on the same PCB circuit board 50, which is advantageous in saving the mounting footprint of the PCB circuit board and simplifying the mounting.

The sensor assembly may be a sensor chipset, such as a hall sensor chipset or a giant magnetoresistive chipset. Signal processing circuitry is integrated in the chip in each sensor assembly. The signal processing circuit processes an electric signal sensed by a sensor in the sensor unit to output a digital signal relating to the rotational speed to a control device of at least one of a joint, a robot arm having the joint, and a robot having the joint. The control means may adjust the output rotation speed of the drive means according to a predetermined program based on the received digital signal, or correct the output rotation speed of the drive means according to the generated error. Here, the error refers to a difference between the measured rotational speed and the desired rotational speed.

The drive is mounted and fixed in the joint housing 20 and may be a dual motor, a dual shaft motor or a motor and transmission system or other various configurations. The motor and transmission system includes a motor and a transmission, which may be driven by the motor and may be a speed reducer, a transmission or a speed increasing device. As shown in fig. 1, the drive device extends towards one side thereof with two concentrically rotating shafts, i.e. an outer shaft 11 and an inner shaft 12. For example, the outer shaft 11 is driven to rotate by a motor, and the inner shaft 12 is driven to rotate by a transmission. The outer shaft 11 may be the drive shaft of the revolute joint, for example, the outer shaft 11 may be directly the motor output shaft of the revolute joint. The inner shaft 12 may be or be connected to or part of the output shaft of the revolute joint. The outer shaft 11 surrounds the inner shaft 12 and is radially spaced from the inner shaft 12 so that the outer and

inner shafts

11, 12 can rotate independently of each other.

In one embodiment, the outer shaft 11 extends from the drive means a shorter length than the inner shaft 12 extends from the drive means, i.e. as shown in fig. 1 and 2, the outer shaft 11 is a hollow shaft and the inner shaft 12 extends a certain length from the end of the hollow outer shaft 11. It is obvious that the inner shaft 12 can also be designed as a hollow shaft, as shown in fig. 1 and 2, which not only reduces the weight of the inner shaft, but also serves as a spool for the revolute joint. It is also possible, if necessary, to design the inner shaft 12 as a solid shaft or to design the inner shaft 12 so that its end does not extend beyond the end of the outer shaft 11.

The outer shaft 11 has an end connected to the first connecting shaft 61, and the inner shaft 12 has an end connected to the second connecting shaft 62. The first connecting shaft 61 is used for mounting the first disc assembly 31, and the second connecting shaft 62 is used for mounting the second disc assembly 32.

The mounting structure of the encoder assembly 30 to monitor the drive shaft and the output shaft of the rotary joint using the first connecting shaft 61 and the second connecting shaft 62 will be described in detail below with reference to fig. 1 to 4.

The first connecting shaft 61 is a hollow shaft, the second connecting shaft 62 is also a hollow shaft, and at any position in the axial direction, the outer diameter of the second connecting shaft 62 is smaller than the inner diameter of the first connecting shaft 61, that is, the first connecting shaft 61 is located on the radial outer side of the second connecting shaft 62. That is, the second connecting shaft 62 is located in a hollow portion of the first connecting shaft 61, surrounded by the hollow first connecting shaft 61, and spaced apart therefrom in the radial direction.

The first connecting shaft 61 has a first end fixedly connected to the end of the outer shaft 11 and a second end for mounting the first disc assembly 31. The second connecting shaft 62 has a first end fixedly connected to the end of the inner shaft 12 and a second end for mounting the second disc assembly 32. The first connecting shaft 61 and the outer shaft 11 may be connected by interference fit, and the second connecting shaft 62 and the inner shaft 12 may be connected by interference fit. In addition, if necessary, an adhesive may be applied between the first connecting shaft 61 and the outer shaft 11 and/or between the second connecting shaft 62 and the inner shaft 12.

Thereby, the first connecting shaft 61, the outer shaft 11 and the first disk assembly 31 rotate synchronously, and the rotation speed of the first disk assembly 31 is the rotation speed of the driving shaft of the rotary joint; the second connecting shaft 62, the inner shaft 12 and the second disc assembly 32 rotate synchronously, and the rotation speed of the second disc assembly 32 is the rotation speed of the output shaft of the rotary joint.

A bearing 70, such as a deep groove ball bearing, is mounted between the first connecting shaft 61 and the second connecting shaft 62. The outer race of the bearing 70 contacts the inner surface of the first connecting shaft 61, and the inner race of the bearing 70 contacts the outer surface of the second connecting shaft 62. Preferably, a bearing 70 is installed at the second end of the first connecting shaft 61 with an end surface of one end flush with an end surface of the second end of the first connecting shaft 61 and the other end abutting against a bearing positioning shoulder 623 formed on the outer surface of the second connecting shaft 62. A bearing positioning shoulder 613 may also be formed on the inner surface of the first connecting shaft 61. In order to secure the connection of the bearing 70 with the first connecting shaft 61 and the second connecting shaft 62, an adhesive, such as 609 glue, may also be applied between the outer race of the first connecting shaft 61 and the bearing and the inner race of the second connecting shaft 62 and the bearing 70. In order to ensure a firm mounting, the connection between the bearing 70 and the first connecting shaft 61 and the second connecting shaft 62 is preferably an interference fit connection.

Further, as shown in fig. 1 and 2, a first coupling positioning shoulder 611 for positioning the mounting position of the first coupling shaft 61 with respect to the outer shaft 11 is also formed on the inner peripheral surface of the first end of the first coupling shaft 61, and a second coupling positioning shoulder 621 for positioning the mounting position of the second coupling shaft 62 with respect to the inner shaft 12 is also formed on the outer peripheral surface or the end surface of the first end of the second coupling shaft 62. As shown in fig. 1, when the first connecting shaft 61 is mounted in place, the end of the outer shaft 11 abuts against the first connection positioning shoulder 611, and when the second connecting shaft 62 is mounted in place, the end of the inner shaft 12 abuts against the second connection positioning shoulder 621.

However, the present application is not limited thereto, and in the case where the sizes of the outer shaft 11 and the inner shaft 12 are appropriate, the first connection positioning shoulder 611 may also be formed on the outer peripheral surface of the first connecting shaft 61, and the second connection positioning shoulder 611 may also be formed on the inner peripheral surface of the second connecting shaft 62.

In the case where the inner space of the revolute joint is sufficient, an additional module positioning shoulder 623 may also be formed on the outer peripheral surface of the first connecting shaft 61. For example, the brake modules may be mounted on the outer circumferential surface of the first connecting shaft 61 using the additional module positioning shoulder 623. In one embodiment, a brake module can be mounted between the attachment module positioning shoulder 623 and the encoder assembly 30 to brake the outer shaft 11.

In the embodiment shown in fig. 1-4, the second connecting shaft 62 is a hollow shaft, and a hollow portion thereof is used for passing the wiring harness, so that the second connecting shaft 62 can be used as a joint wire passing shaft. The second connecting shaft 62 may also be a solid shaft in the case where the wire harness in the joint does not need to pass through via the second connecting shaft 62. In the embodiment of the present application, the second connecting shaft 62 may be used not for outputting torque but only for assisting in measuring the rotational speed of the rotating shaft of the transmission or as a spool.

Further, a detachment assisting shoulder 622 may be formed on an inner peripheral surface of the second connecting shaft 62. The detachment assisting shoulder 622 is used to assist the separation operation of the second connecting shaft 62 from the inner shaft 12. Specifically, the second connecting shaft 62 can be separated from the inner shaft 12 by inserting a stepped shaft dedicated for disassembly from the first end side of the second connecting shaft 62 against the disassembly assisting shoulder 622 and pushing the second connecting shaft 62.

The first connecting shaft 61 may be driven in rotation by a motor of the drive means, may be used as a drive shaft for a joint or may be connected to or integrated with a drive shaft for a joint, i.e. the rotational speed of the first connecting shaft 61 is the rotational speed of the drive shaft for a joint. The second connecting shaft 62 may be driven by a transmission, connected to or integrated with the output shaft of the joint. That is, the output of the transmission may be used as the output shaft of the joint, the second connecting shaft 62 rotates in synchronization with the output shaft of the joint, and the rotation speed of the second connecting shaft 62 is the rotation speed of the output shaft of the joint. In the above embodiment, the first connecting shaft 61 may rotate in synchronization with the drive shaft of the revolute joint, and the second connecting shaft 62 may rotate in synchronization with the output shaft of the revolute joint, but it should be noted that the present application is not limited thereto, and the first connecting shaft 61 may rotate in synchronization with the output shaft of the revolute joint, and the second connecting shaft 62 may rotate in synchronization with the drive shaft of the revolute joint, as the structure of the drive device allows.

In some embodiments, the output shaft of the joint and the drive shaft of the joint (e.g., a motor shaft that is a rotary joint) may be located on either side of the drive device. In the embodiment shown in fig. 1-4, the direction of extension of the second connecting shaft 62 and the first connecting shaft 61 is the direction of extension of the drive shaft of the joint (e.g., joint motor shaft). Further, the second end of the second connecting shaft 62 does not exceed the second end of the first connecting shaft 61 in the axial direction. The second end of the first connecting shaft 61 and the second end of the second connecting shaft 62 are respectively used for mounting the

disc assemblies

31 and 32 of the encoder assembly, so that the encoder modules or the encoder assemblies mounted on the two connecting shafts can be compactly mounted on the same side of the driving device along the axial direction, and the reduction of the axial space occupied by and involved in the encoder modules in the joint is facilitated. It will be appreciated by those skilled in the art that the axial space involved may be a necessary relief space, for example, a space reserved for heat dissipation, vibration, and wiring considerations.

As shown in fig. 1, at any position of the first connecting shaft 61 and the second connecting shaft 62 in the axial direction, the outer diameter of the second connecting shaft 62 is smaller than the inner diameter of the first connecting shaft 61, and therefore, the two are spaced apart in the radial direction without direct contact with each other. Thus, the rotation of the first connecting shaft 61 and the second connecting shaft 62 is relatively independent, i.e. the rotation of the first connecting shaft 61 does not interfere with the rotation of the second connecting shaft 62, and the rotation of the second connecting shaft 62 does not interfere with the rotation of the first connecting shaft 61, whereby the rotational speed of the first connecting shaft 61 and the rotational speed of the second connecting shaft 62 may represent the rotational speed of the drive shaft and the rotational speed of the output shaft of the joint, respectively. When the two encoder assemblies are used for measuring the rotating speed of the first connecting shaft 61 and the rotating speed of the second connecting shaft 62 respectively, the actual conditions of the rotating speed of the driving shaft of the joint and the rotating speed of the output shaft can be accurately reflected.

Although the rotational speed of the first connecting shaft 61 and the rotational speed of the second connecting shaft 62 represent the rotational speed of the drive shaft and the rotational speed of the output shaft of the joint, respectively, in the embodiment shown in fig. 1 to 4, the present application is not limited thereto. That is, in the output structure of the driving device, for example, the structure of the motor and the structure of the transmission allow, the first connecting shaft 61 may also be arranged to rotate in synchronization with the output shaft of the joint, and the second connecting shaft 62 may be arranged to rotate in synchronization with the driving shaft of the joint (for example, joint motor shaft).

Further, as described above, in the embodiment of the present application, the gear ratio of the transmission in the driving device may be greater than or equal to 1, and may also be less than or equal to 1. That is, the transmission device may be a speed reducer, a speed increasing device, or even a speed changing device having both speed increasing and speed reducing transmission capabilities, as necessary. Thus, the ratio of the rotational speeds of the drive shaft of the joint and the output shaft of the joint may be 1 or more, or 1 or less.

As previously mentioned, the encoder assembly 30 includes a disc assembly and a sensor assembly. The mounting structure of the encoder assembly 30 in the joint according to the embodiment of the present application will be described in detail with reference to fig. 1 to 4.

As shown in fig. 1 to 4, the encoder assembly 30 includes a first disc assembly 31 mounted on a first connecting shaft 61 and a second disc assembly 32 mounted on a second connecting shaft 62. The first disk assembly 31 includes a first disk 311 and a first mounting bracket 312 for mounting the first disk 311. The first mounting bracket 312 is an annular member having an inner bore through which it is sleeve-fixed to the second end of the first connecting shaft 61. In order to ensure the firm installation, the first mounting bracket 312 is connected with the first connecting shaft 61 by interference fit.

The outer race of first magnetic disk 311 may be secured to the annular portion of first mounting bracket 312 using threaded fasteners such as screws. Thus, when the first connecting shaft 61 rotates, the first disk assembly 31 composed of the first mounting bracket 312 and the first disk 311 rotates in synchronization with the first connecting shaft 61. That is, the rotation speed of the first magnetic disk 311 is the rotation speed of the drive shaft of the joint. In a further embodiment, the first connecting shaft 61 and the first mounting bracket 312 may be formed as an integral member.

The second disk assembly 32 includes a second disk 321 and a second mounting bracket 322 for mounting the second disk 311. The second mounting bracket 312 is an annular member having an inner bore through which it is sleeve-fixed to the second end of the second connecting shaft 62. In order to ensure the firm installation, the second mounting bracket 322 is suitably connected with the second connecting shaft 62 by interference fit. The outer race of the second magnetic disk 321 may be secured to the annular portion of the second mounting bracket 322 using threaded fasteners such as screws. Thus, when the second connecting shaft 62 rotates, the second disk assembly 32 composed of the second mounting bracket 322 and the second disk 321 rotates in synchronization with the second connecting shaft 62. That is, the rotation speed of the second magnetic disk 321 is the rotation speed of the output shaft of the joint. In further embodiments, the second connecting shaft 62 and the second mounting bracket 322 may also be formed as an integral member.

In the present embodiment, the distance between the mounting position of the first mounting bracket 312 on the first connecting shaft 61 and the end surface of the first magnetic disk 311 is larger than the distance between the position of the second mounting bracket 322 on the second connecting shaft 62 and the end surface of the second magnetic disk 321. The first mounting bracket 312 may include a first disk mounting portion, a first connecting shaft mounting portion having an inner bore, and a connecting portion connecting the two. As shown in fig. 1 and 2, the connection portion may be formed as an inclined portion to reserve an installation space for the second mounting bracket 322 in the axial direction, so as not to cause any interference between the first mounting bracket 312 and the second mounting bracket 322 in the axial direction or the radial direction to affect the rotation speed of the magnetic disk or to cause magnetic field interference between two magnetic disks. The inclination angle of the connection portion may be greater than or equal to 90 degrees. Further, the connecting portion may be formed in a curved shape.

In the present embodiment, although the first and second

magnetic disks

311 and 321 are mounted on the first and second connecting

shafts

61 and 62, respectively, by the first and second mounting

brackets

312 and 322, it will be understood by those skilled in the art that, for example, in the case where the inner hole of the second magnetic disk 321 is appropriate in size, it is contemplated that the second magnetic disk 321 may be directly mounted on the second connecting shaft 62. That is, the manner in which the first and second

magnetic disks

311 and 321 are fixedly connected to the first and second connecting

shafts

61 and 62, respectively, is not limited to the manner described above, as long as any mounting structure that can ensure the first and second

magnetic disks

311 and 321 rotate in synchronization with the first and second connecting

shafts

61 and 62, respectively, is permissible.

Still further, the mounting of first and

second disks

311, 312 to be coplanar facilitates reducing the axial space occupied or involved by encoder assembly 30 in the joint. As shown in fig. 1 and 2, first magnetic disk 311 may be located radially outward of second magnetic disk 321, and first magnetic disk 311 and second magnetic disk 321 may be radially spaced apart to avoid magnetic field interference therebetween, resulting in distortion of the electrical signal received by the corresponding sensor assembly.

As previously described, the encoder assembly 30 also includes a first sensor assembly mounted adjacent the first disk 311 and a second sensor assembly mounted adjacent the second disk 321. The first sensor assembly is used to detect rotational movement of the first magnetic disk 311 and the second sensor assembly is used to detect rotational movement of the second magnetic disk 321. Although not explicitly shown, both the first sensor assembly and the second sensor assembly are mounted on a PCB circuit board 50, which will be described in detail below. That is, the first sensor assembly (particularly, the sensor of the first sensor assembly) may face the first magnetic disk 311, and the second sensor assembly (particularly, the sensor of the second sensor assembly) may face the second magnetic disk 321. The first sensor assembly generates a digital signal regarding the rotational speed of the first spindle 61 based on the electrical signal generated by the rotation of the first magnetic disk 311, and the second sensor assembly generates a digital signal regarding the rotational speed of the second spindle 62 based on the electrical signal generated by the rotation of the second magnetic disk 321. The control means of at least one of the joint, the robot arm and the robot may receive these digital signals from the first sensor assembly and the second sensor assembly to feedback control or adjust control of the drive means of the joint as required, thereby precisely controlling the joint and the specific motion of the robot arm or robot having the joint.

In the above embodiment, the first sensor assembly and the second sensor assembly are mounted on the same PCB 50, which not only improves the integration of the circuit, saves the occupied space and the avoiding space of the PCB, but also reduces the heat dissipation problem, reduces the length of the wire harness, and simplifies the connection of the wire harness.

As shown in fig. 1, the PCB circuit board 50 is installed parallel to the first magnetic disk 311 and the second magnetic disk 321, and is fixedly coupled to one end of the joint housing by the coupling assembly 40. The connection assembly 40 is interposed between one end of the joint housing and the PCB circuit board 50, and has one end connected to one end of the joint housing and the other end connected to the PCB circuit board 50, and maintains a certain interval between the PCB circuit board 50 and one end of the joint housing. The spacing is slightly greater than the designed extension of the first and

second disc assemblies

31 and 32 relative to one end of the joint housing. When both sensor assemblies are mounted on the PCB 50, it is necessary to ensure that a proper gap is maintained between the end surfaces of the first and

second disk assemblies

31 and 32 and the sensor assemblies on the PCB 50 so that the

sensor assemblies

31 and 32 can accurately detect the rotation speeds of the first and second

magnetic disks

311 and 321. Preferably, the design protrusion length is greater than the thickness of the disc assembly. In this application, the thickness of the disc assembly may refer to a distance between the disc surface of the disc assembly and the rear surface of the mounting bracket thereof, and the disc assembly can be detached by clamping the thickness of the disc assembly. In other words, the thickness of the disc assembly means the thickness that can be clamped at the outer circumference of the disc assembly. For disc assemblies in this application that include both first disc assemblies 31 and second disc assemblies 32 in a coplanar arrangement, the thickness of a disc assembly refers to the thickness of the disc assembly 31 that is radially outward.

In mounting the first disc assembly 31 and the second disc assembly 32, the first connecting shaft 61 is first mounted to the outer shaft 11, so that the tip of the outer shaft 11 abuts the first connecting locating shoulder 611, the second connecting shaft 62 is then connected to the inner shaft 12, so that the end of the inner shaft 12 abuts the second connecting locating shoulder 621, then the inner ring of the bearing 70 is glued 609 and pressed between the first connecting shaft 61 and the second connecting shaft 62, first disk assembly 31 is then formed by mounting first disk 311 on first mounting bracket 312, and the second disk 321 is mounted on the second mounting bracket 322 to form the second disk assembly 32, the first disk assembly 31 is fitted over the first connecting shaft 61, the second disk assembly 32 is fitted over the second connecting shaft 62, then, the two

disc assemblies

31 and 32 are simultaneously press-fitted in the axial direction onto the two connecting

shafts

61 and 62 connected to the inner shaft 12 and the outer shaft 11 of the driving device, respectively, using a disc press-fitting jig 14 such as that shown in fig. 2. By simultaneously press-fitting the two

disk assemblies

31 and 32 using the disk press-fitting jig 14, it is possible to ensure that the distance from the end surfaces of the two disks (i.e., the disk surfaces facing the PCB 50 or the sensor assembly) to the end surface of the joint housing and the coplanarity of the two disks (i.e., the disk surfaces) meet requirements.

After the disk assembly is mounted in place, the disk press-fitting jig 14 is removed, and then the PCB circuit board 50 is fixed (e.g., fixed to the joint housing or the drive device) using the connecting assembly 40 and the gap between the PCB circuit board 50 and the end surfaces of the two disks (i.e., the disk surfaces) is adjusted. By ensuring that the gap between the PCB 50 and the end surfaces of the two disks is appropriate, each sensor assembly can accurately detect the change in the magnetic field of the corresponding disk assembly due to rotation, thereby outputting a digital signal regarding the rotational speed of the corresponding connecting shaft, thereby obtaining rotational speed information of the drive shaft of the revolute joint and the output shaft of the revolute joint. After the encoder module is installed in place, as shown in fig. 1, the encoder module or encoder assembly may be installed to extend a predetermined length relative to one end of the joint housing to facilitate subsequent removal of the encoder module.

The connection assembly 40 may include spacer columns, such as cylindrical or hex-shaped spacer columns, wherein each end of each spacer column may be formed with internal or external threads. One end of the spacer may be threadedly coupled to one end of the joint housing, and the other end of the spacer may be threadedly coupled to the PCB 50. More specifically, one end of the spacer may be connected with at least one of an end surface, an inner wall, or an outer wall of one end of the joint housing, and the other end of the spacer may be screw-connected with the PCB circuit board 50 by an additional screw, bolt, or nut. When one end of the isolation column is connected with the inner wall or the outer wall of one end of the joint shell, corresponding inner bulges or outer bulges can be formed on the inner wall or the outer wall of the joint shell. Through holes or screw holes may be formed in the inner protrusion or the outer protrusion for connection. The connecting members 40 are at least two, preferably 3, 4, 5, 6 or more. The number of the connecting members 40 may be determined according to the size of the joint housing and the shape and weight of the PCB circuit board and the specification of the isolating column.

The connection assembly 40 is not limited to an isolation post having internal or external threads on both ends. For example, the connection assembly 40 may further include at least one boss projecting axially on at least one of an inner wall, an outer wall, and/or an end surface of one end of the joint housing and a threaded fastener threadedly coupled with the boss. The boss protrudes a predetermined distance with respect to one end of the joint housing and is integrally formed with the joint housing, wherein a screw hole is formed in the boss. The PCB circuit board 50 is connected and fixedly connected to the joint housing by the coupling between the screw fastener and the boss, which allows the PCB circuit board 50 to be fixed to the joint housing in such a manner as to be spaced apart from one end of the joint housing by a predetermined distance.

As shown in fig. 1, the PCB circuit board 50 has a central hole for passing a cable or a wire harness therethrough. The end of the second connecting shaft 62 does not extend to the PCB 50 or pass through the PCB 50, but is spaced apart from the PCB 50 in the axial direction of the drive device and flush with the disk surface of the disk assembly. As can be seen in conjunction with the foregoing description, the first mounting bracket 312 and the second mounting bracket 322 are located on one side of the first disk and the second disk and are axially connected without a gap therebetween, while the PCB 50 is located on the other side of the first disk and the second disk and is axially spaced therefrom. Through the compact arrangement of the PCB and the first disk assembly and the second disk assembly respectively arranged on the first connecting shaft 61 and the second connecting shaft 62, the occupation of the axial space of the encoder module in the rotary joint can be effectively reduced.

In one embodiment, the connection assembly 40 may be a standoff post, and may also be a post and threaded fastener, and both types of connection assemblies may be used simultaneously for connection of the PCB 50 to one end of the joint housing 20 in one joint.

In order to facilitate installation and disassembly, the isolation column can be a hexagonal stud with an external thread at one end and an internal thread at the other end. One end of the hex stud may be screwed into the end surface of one end of the knuckle housing and the other end may be screwed through a through hole in the PCB 50. By changing the screwing depth of one end of the hexagonal stud, the distance between the PCB 50 and one end of the joint housing can be adjusted to adjust the gap between the disc assembly and the sensor assembly.

In the above embodiment, when disassembling the encoder module, the PCB 50 may be disassembled and then the first and

second disc assemblies

31 and 32 may be simultaneously disassembled from the first and second connecting

shafts

61 and 62 by using the disc disassembling jig. The second connecting shaft 62 and the bearing 70 are then removed simultaneously using the aforementioned stepped shaft, and finally the first connecting shaft 61 is removed.

In the embodiment of the application, the steps (namely, shaft shoulders) for mounting the bearings are formed at the positions, close to the disk mounting bracket, of the tail ends of the first connecting shaft and the second connecting shaft, so that the coaxiality of two slender shafts extending out of the driving device in the joint shell and the rigid supporting capacity of the two shafts are guaranteed, the two shafts are not hindered from rotating independently, the concentric installation of the encoder module and the driving shaft and the output shaft of the rotary joint is guaranteed, and the occurrence of asymmetry or angle error is avoided. The structure also improves the robustness of the encoder module to impact and vibration. Meanwhile, the end surfaces of the second ends of the two connecting shafts are respectively flush with the surfaces of the corresponding magnetic disks, so that the length of the slender shaft is shortened to the maximum extent, the processing difficulty of a product is reduced, and the installation and adjustment of the encoder module are simplified.

In addition, the installation of the bearing, the input disk support and the output disk support of the encoder module can adopt the installation mode of combining step shaft positioning and interference press fit and simultaneously coating an adhesive, the assembly structure of the encoder module is simplified, and the installation and the disassembly are further facilitated.

In the embodiment of the present application, the specific position of the one end of the joint housing to which the connection assembly is connected may be properly selected according to the size and structure of the joint housing, the size and structure of the PCB circuit board, and the size of the first disc assembly in the encoder assembly, without being limited to a certain fixed position.

According to at least one embodiment of the application, the connection mode of the PCB and the joint shell not only facilitates the installation and the disassembly of the PCB and the encoder assembly, but also facilitates the adjustment of the gap between the end surfaces of the sensor assembly on the PCB and the magnetic disc in the encoder assembly, and further improves the assembly efficiency of the joint.

In addition, the input magnetic disc and the output magnetic disc (namely, the first magnetic disc and the second magnetic disc) in the joint encoder module are arranged on the same end face and only one PCB is used, so that the radial space can be fully utilized, the axial space of the joint is greatly saved, and the system integration is improved to be beneficial to the miniaturization design of products. Simultaneously, two magnetic disks can be installed simultaneously, the position is adjusted simultaneously, the magnetic disks are dismounted simultaneously, and the same tool jig is used, so that the installation precision and the installation efficiency are improved.

In addition, by centralizing the encoder modules for the drive shaft (e.g., joint motor shaft) and output shaft of the joint at one end of the joint housing, adjustment of the gap between the disk and the sensor on the PCB circuit board is further simplified (since the gap between the disk and the sensor is very critical). The arrangement mode can use the precise press mounting of the magnetic disk mounting jig, the link of adjusting the gap is reduced, and the encoder module structure is more suitable for severe industrial environments with extreme temperature, humidity and particle pollution.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and the like are used in the indicated orientations and positional relationships based on the drawings, merely to facilitate description of the application and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. An encoder module for a rotary joint, the rotary joint including a drive device having an inner shaft extending toward a same side and an outer shaft surrounding the inner shaft and radially spaced from the inner shaft, the encoder module comprising:

a first connecting shaft having a first end and a second end, the first end of the first connecting shaft for connecting with an end of the outer shaft;

the first end of the second connecting shaft is used for being fixedly connected with the inner shaft;

a first disk assembly secured to the first connecting shaft;

a second disc assembly fixed to the second connecting shaft;

a first sensor assembly disposed adjacent to the first disk assembly;

a second sensor assembly disposed adjacent to the second disk assembly,

wherein the disk surfaces of the first disk assembly and the second disk assembly are arranged to be coplanar and radially separated by at least a predetermined distance.

2. The encoder module of claim 1, wherein the encoder module further comprises a bearing mounted between the first connecting shaft and the second connecting shaft.

3. The encoder module of claim 2, wherein the first connecting shaft is a hollow shaft and is formed with a first bearing locating shoulder on an inner peripheral surface thereof, and/or a second bearing locating shoulder is formed on an outer peripheral surface of the second connecting shaft.

4. The encoder module of claim 3, wherein a first coupling locating shoulder is formed on an inner or outer peripheral surface of the first end of the first coupling shaft for locating a mounting position of the first coupling shaft relative to the outer shaft.

5. The encoder module of claim 3 or 4, wherein an additional module positioning shoulder is formed on an outer peripheral surface of the first connecting shaft.

6. The encoder module of claim 3, wherein a second coupling positioning shoulder is formed on an outer peripheral surface of the second coupling shaft or an end surface of the first end for positioning a mounting position of the second coupling shaft with respect to the inner shaft.

7. The encoder module of claim 3, wherein the second connecting shaft is a hollow shaft, and the inner peripheral surface is formed with a second connection positioning shoulder for positioning an installation position of the second connecting shaft with respect to the inner shaft and/or a removal assisting shoulder for separating the second connecting shaft from the inner shaft.

8. The encoder module of claim 2, wherein an end surface of the second end of the first coupling shaft is flush with an outer end surface of the bearing, and an end surface of the second end of the second coupling shaft is flush with a disk surface of the first disk assembly and a disk surface of the second disk assembly.

9. The encoder module of claim 2, wherein the bearing is bonded to at least one of the first connecting shaft and the second connecting shaft by an adhesive.

10. The encoder module of claim 2, wherein the bearing is a deep groove ball bearing, and an inner race of the bearing is bonded to the second connecting shaft with an adhesive.

11. The encoder module of claim 1, wherein the encoder module structure further comprises a PCB circuit board on which the first sensor assembly and the second sensor assembly are mounted, wherein the PCB circuit board is parallel to and spaced apart from the disk surfaces of the first disk assembly and the second disk assembly.

12. The encoder module of claim 1, wherein the first disk assembly comprises a first disk and a first mounting bracket supporting the first disk, the first mounting bracket being mounted to the second end of the first connecting shaft.

13. The encoder module of claim 1 or 11, wherein the second disc assembly comprises a second disc and a second mounting bracket supporting the second disc, the second mounting bracket being mounted at the second end of the second connecting shaft.

14. The encoder module of claim 13, wherein the first mounting bracket is spaced apart from the first mounting bracket both axially and radially, wherein the first mounting bracket and the first connecting shaft are separately or integrally formed, and wherein the second mounting bracket and the second connecting shaft are separately or integrally formed.

15. The encoder module of claim 13, wherein the outer and/or inner race of the first disk is secured to the first mounting bracket and the outer and/or inner race of the second disk is secured to the second mounting bracket.

16. A revolute joint for a robot having a joint housing, a drive arrangement as claimed in claim 1 and an encoder module for a revolute joint as claimed in any one of claims 1 to 15.

17. The revolute joint for a robot of claim 16, wherein the drive means comprises a motor and a transmission driven by the motor, wherein the motor drives one of the inner shaft and the outer shaft and the transmission drives the other of the outer shaft and the inner shaft.

18. The revolute joint for a robot of claim 16, wherein the drive means is mounted within the joint housing, the encoder module extending a predetermined length relative to one end of the joint housing.

19. The revolute joint for a robot of claim 16, further comprising control means for adjusting the operation of the drive means based on the signals output by the first and second sensor assemblies.

20. A robot arm for a robot comprising at least one revolute joint for a robot as claimed in any one of claims 16 to 19.

21. A robot comprising at least one revolute joint for a robot according to any one of claims 16 to 19.