Rotary joint and device equipped with same

Abstract

The rotary joint includes a joint housing (20), a drive unit mounted within the joint housing (20), and an encoder module (30) mounted to the drive unit, the drive unit having an inner shaft (12) and an outer shaft (11) surrounding the inner shaft (12) and spaced radially from the inner shaft (12), the encoder module (30) including a first magnetic disk assembly (31) configured to rotate in synchronism with the outer shaft (11), a second magnetic disk assembly (32) configured to rotate in synchronism with the inner shaft (12), and a second magnetic disk assembly (32) configured to rotate in synchronism with the outer shaft (11). a first sensor assembly disposed adjacent to the first magnetic disk assembly (31) for detecting a movement of the magnetic disk of the first magnetic disk assembly (31), and a second sensor assembly disposed adjacent to the second magnetic disk assembly (32) for detecting a movement of the magnetic disk of the second magnetic disk assembly (32), wherein a magnetic disk surface of the first magnetic disk assembly (31) and a magnetic disk surface of the second magnetic disk assembly (32) are disposed flush with each other and are spaced apart in a radial direction by at least a predetermined distance. There is further provided an apparatus including at least one rotary joint.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority to a Chinese patent application filed on December 30, 2021, bearing application number 2021116546078 and titled "Encoder module for rotary joint, rotary joint, robot arm and robot", and a Chinese utility model application filed on December 30, 2021, bearing application number 2021234015621 and titled "Joint for robot and robot arm and robot having said joint", the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the field of robotics, and in particular to a rotary joint for a robot, and to a device equipped with such a rotary joint, such as a robot arm or a robot. [Background technology]

[0003] In short, a robot with a robot arm controls the relative motion between the components of the robot arm by means of joints. Joints are usually divided into rotational joints and translational joints (also called prismatic joints). The rotational joints are connected to two members respectively by a drive unit and are rotatable, thereby generating relative motion between the two members. In order to accurately control the movement and position of the robot arm, it is necessary to accurately measure the rotation speed of the two output shafts of the drive unit and adjust the rotation speed of each output shaft based on the measured rotation speed.

[0004] Usually, the rotation speed of the two output shafts of the drive is measured by an encoder. An encoder is a device that converts a signal into a sine wave by magnetic or optical measurement principle. Magnetic encoders can achieve a resolution as low as 1 micrometer, can withstand vibration, and are resistant to contamination and corrosion caused by dust, oil stains, water vapor, and salt spray, and are more robust and durable than optical encoders, so they are widely used in the field of robotics, where the movement position must be accurately controlled.

[0005] A magnetic encoder includes a magnetic disk, a sensor, and a conditioning circuit. The magnetic disk is already magnetized and has multiple magnetic poles distributed around its circumference, with two adjacent magnetic poles having opposite polarities. The sensor detects the change in the magnetic field as the magnetic disk rotates and converts the information into a sine wave. The sensor may be a Hall element that senses the change in voltage, or a magnetoresistance element that senses the change in the magnetic field. The conditioning circuit multiplies, divides, or interpolates the signal to generate the desired output.

[0006] In a robot joint, the two output shafts of the drive unit are usually located on both sides of the drive unit, and accordingly, two sets of magnetic encoder modules are also located on both sides of the drive unit. Each magnetic encoder module has a magnetic disk and a PCB circuit board having a sensor chip, the magnetic disk is fixed to the output shaft, and the corresponding PCB circuit board is fixedly attached to the drive unit. Summary of the Invention [Means for solving the problem]

[0007] According to one aspect of the present disclosure, there is provided a rotary joint including a joint housing, a drive unit mounted within the joint housing, and an encoder module mounted to the drive unit, the drive unit having an inner shaft and an outer shaft surrounding the inner shaft and spaced radially from the inner shaft, the encoder module including a first magnetic disk assembly configured to rotate synchronously with the outer shaft, a second magnetic disk assembly configured to rotate synchronously with the inner shaft, a first sensor assembly disposed adjacent to the first magnetic disk assembly and configured to detect movement of a magnetic disk of the first magnetic disk assembly, and a second sensor assembly disposed adjacent to the second magnetic disk assembly and configured to detect movement of the magnetic disk of the second magnetic disk assembly, wherein a magnetic disk surface of the first magnetic disk assembly and a magnetic disk surface of the second magnetic disk assembly are disposed flush with each other and are spaced radially apart by at least a predetermined distance.

[0008] In at least one embodiment of the present application, the encoder module may further include a first connecting shaft having a first end and a second end, the first end of the first connecting shaft being connected to an end of the outer shaft, a second connecting shaft having a first end and a second end, the first end of the second connecting shaft being fixedly connected to the inner shaft, and a bearing mounted between the first connecting shaft and the second connecting shaft. The first magnetic disk assembly may be fixed to the first connecting shaft. The second magnetic disk assembly may be fixed to the second connecting shaft.

[0009] In at least one embodiment of the present application, the first connecting shaft may be a hollow shaft having a first bearing locating shoulder formed on its inner circumferential surface, and / or the second connecting shaft may have a second bearing locating shoulder formed on its outer circumferential surface.

[0010] In at least one embodiment of the present application, a first connection positioning shoulder for positioning an attachment position of the first connection shaft relative to the outer shaft may be formed on an inner or outer peripheral surface of the first end of the first connection shaft.

[0011] In at least one embodiment of the present application, an additional module positioning shoulder may be formed on an outer circumferential surface of the first connecting shaft.

[0012] In at least one embodiment of the present application, a second connection positioning shoulder for positioning an attachment position of the second connection shaft relative to the inner shaft may be formed on an outer circumferential surface of the second connection shaft or an end face of the first end.

[0013] In at least one embodiment of the present application, the inner shaft may be a hollow shaft and may extend from the outer shaft by a certain length. The second connecting shaft may be a hollow shaft. The inner circumferential surface may be formed with a second connection positioning shoulder and / or a detachment auxiliary shoulder. The second connecting positioning shoulder is configured to position an attachment position of the second connecting shaft relative to the inner shaft. The detachment auxiliary shoulder is configured to separate the second connecting shaft from the inner shaft.

[0014] In at least one embodiment of the present application, an end surface of the second end of the first connection shaft is flush with an outer end surface of the bearing, and an end surface of the second end of the second connection shaft is flush with a magnetic disk surface of the first magnetic disk assembly and a magnetic disk surface of the second magnetic disk assembly.

[0015] In at least one embodiment of the present application, the bearing may be adhered to at least one of the first connecting shaft and the second connecting shaft by an adhesive.

[0016] In at least one embodiment of the present application, the bearing may be a deep groove ball bearing, and an inner ring of the bearing may be bonded to the second connecting shaft by an adhesive.

[0017] In at least one embodiment according to the present application, the encoder module may further include a PCB circuit board on which the first sensor assembly and the second sensor assembly are mounted, the PCB circuit board being parallel to and spaced apart from a magnetic disk surface of the first magnetic disk assembly and a magnetic disk surface of the second magnetic disk assembly.

[0018] In at least one embodiment of the present application, the PCB circuit board may be fixed to at least one of an inner wall, an outer wall, and an end surface of one end of the joint housing, and the PCB circuit board is spaced a predetermined distance from the one end of the joint housing, the predetermined distance being at least greater than a total thickness of the first magnetic disk module and the second magnetic disk module.

[0019] In at least one embodiment of the present application, the PCB circuit board is directly fixed to the joint housing via at least one spacer post, each end of which is formed with an internal or external thread.

[0020] In at least one embodiment of the present application, the joint housing includes at least one boss provided on at least one of an inner wall, an outer wall and / or an end surface of the one end of the joint housing, and a screw fastener screwed into the boss. The one boss protrudes a predetermined distance from the one end of the joint housing, and a screw hole is formed in each boss. The PCB circuit board is connected by coupling the screw fastener with the boss and is fixedly connected to the joint housing.

[0021] In at least one embodiment of the present application, the PCB circuit board may have a central hole for passing a cable through.

[0022] In at least one embodiment of the present application, the first sensor assembly and / or the second sensor assembly may include a sensor and an adjustment circuit integrated on a chip, and the sensor may be a Hall sensor or a giant magnetoresistive sensor.

[0023] In at least one embodiment of the present application, the first magnetic disk assembly may include a first magnetic disk and a first mounting bracket that supports the first magnetic disk. The first mounting bracket may be attached to a second end of the first connecting shaft.

[0024] In at least one embodiment of the present application, the second magnetic disk assembly may include a second magnetic disk and a second mounting bracket that supports the second magnetic disk. The second mounting bracket may be attached to a second end of the second connecting shaft.

[0025] In at least one embodiment of the present application, the first mounting bracket and the second mounting bracket are spaced apart both in the axial direction and the radial direction. The first mounting bracket and the first connecting shaft are formed separately or integrally, and the second mounting bracket and the second connecting shaft are formed separately or integrally.

[0026] In at least one embodiment of the present application, an outer ring and / or an inner ring of the first magnetic disk may be fixed to the first mounting bracket, and an outer ring and / or an inner ring of the second magnetic disk may be fixed to the second mounting bracket.

[0027] In at least one embodiment of the present application, the drive device may include a motor and a transmission device driven by the motor, the motor being capable of driving one of the inner shaft and the outer shaft, and the transmission device being capable of driving the other of the outer shaft and the inner shaft.

[0028] In at least one embodiment of the present application, the drive unit may be mounted within the joint housing, and the encoder module may extend beyond one end of the joint housing by a predetermined length.

[0029] In at least one embodiment of the present application, the rotary joint may further include a control device configured to adjust the operation of the drive unit based on signals output from the first sensor assembly and the second sensor assembly.

[0030] According to another aspect of the present disclosure, there is provided an apparatus including at least one revolute joint as described above.

[0031] In at least one embodiment of the present application, the device includes a robot, a robotic arm, or the like.

[0032] In order to more clearly describe the technical means in the embodiments of the present application or the prior art, the following briefly describes the drawings that need to be used in the description of the embodiments or the prior art. It is obvious that the drawings in the following description are only the embodiments of the present application, and those skilled in the art can obtain other drawings based on the disclosed drawings without creative labor. [Brief description of the drawings]

[0033] [Figure 1] FIG. 2 is a partial front view showing a schematic structure and mounting method of an encoder module in a joint according to an embodiment of the present application. [Diagram 2] FIG. 2 is a partial cross-sectional view illustrating a schematic structure of an encoder module in a rotary joint according to an embodiment of the present application. [Diagram 3] 1 is a partial cross-sectional view showing a schematic structure and mounting method of a magnetic disk assembly of an encoder module in a rotary joint according to an embodiment of the present application; [Figure 4] FIG. 13 is a cross-sectional view illustrating a schematic partial mounting structure of two magnetic disk assemblies of an encoder module in a rotary joint according to an embodiment of the present application. [Diagram 5] 1 is a perspective view showing a schematic combination structure of a magnetic disk assembly and a connection shaft in an encoder module according to an embodiment of the present application; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Hereinafter, the technical means in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of them. Based on the embodiments of the present application, all other embodiments that a person skilled in the art can obtain without creative labor all belong to the protection scope of the present application.

[0035] Specific examples of the present invention will be described in detail below with reference to FIGS. 1 to 5. FIG.

[0036] 1 to 5, a rotary joint according to an embodiment of the present application includes a drive unit (not shown), a joint housing 20, and an encoder assembly 30. The drive unit is fixedly attached to the joint housing 20, and has two shafts, that is, an outer shaft 11 and an inner shaft 12, which protrude toward the same side of the drive unit and rotate about the same axis. The outer shaft 11 is a hollow shaft, which surrounds the inner shaft 12 and is radially spaced from the inner shaft. As a result, the inner shaft 12 and the outer shaft 11 rotate independently of each other.

[0037] The encoder assembly 30 includes a magnetic disk assembly and a sensor assembly, and the sensor assembly may be mounted on a PCB circuit board 50, which may be mounted perpendicular to the output shaft of the drive device. Specifically, the magnetic disk assembly includes a first magnetic disk assembly 31 that rotates synchronously with the outer shaft 11 and a second magnetic disk assembly 32 that rotates synchronously with the inner shaft 12. The sensor assembly includes a first sensor assembly (not shown) that detects a change in a magnetic field caused by the rotation of the first magnetic disk assembly 31, and a second sensor assembly (not shown) that detects a change in a magnetic field caused by the rotation of the second magnetic disk assembly 32.

[0038] The PCB circuit board 50 is fixedly attached to the driving device through the connection assembly 40, for example, fixed to the joint housing 20. In one embodiment, the PCB circuit board is attached parallel to and spaced apart from the magnetic disk of the magnetic disk assembly, for example, connected to one end of the joint housing 20 and spaced apart from the one end of the joint housing 20 by a predetermined distance. The first sensor assembly and the second sensor assembly may be attached to different circuit boards, but in this application, it is proposed to be attached to the same PCB circuit board 50, which is advantageous for saving the mounting space of the PCB circuit board and simplifying the mounting.

[0039] The sensor assembly may be a sensor chip set, such as a Hall sensor chip set or a giant magnetoresistance chip set. A signal processing circuit is integrated in the chip in each sensor assembly. The signal processing circuit processes the electric signal detected by the sensor in the sensor assembly and outputs a digital signal related to the rotation speed to at least one of a control device of the joint, the robot arm having the joint, and the robot having the joint. The control device can adjust the output rotation speed of the drive device according to a predetermined program based on the received digital signal, or correct the output rotation speed of the drive device according to an error that occurs. Here, the error is the difference between the measured rotation speed and the desired rotation speed.

[0040] The drive is attached and fixed to the joint housing 20 and may be in various arrangements such as two motors, a two-shaft motor, or a motor and transmission system. The motor and transmission system includes a motor and a transmission, and the transmission may be driven by the motor or may be a reducer, a speed changer, or a speed increaser. As shown in Figures 1 and 2, the drive has two concentrically rotating shafts extending from one side thereof, namely an outer shaft 11 and an inner shaft 12. For example, the outer shaft 11 is driven to rotate by the motor, and the inner shaft 12 is driven to rotate by the transmission. The outer shaft 11 may be the drive shaft of a revolute joint, for example, the outer shaft 11 may be the motor output shaft of the revolute joint. The inner shaft 12 may be the output shaft of the revolute joint, may be connected to the output shaft of the revolute joint, or may be 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 shaft 11 and the inner shaft 12 can rotate independently.

[0041] In one embodiment, the length of the outer shaft 11 that protrudes from the drive unit is shorter than the length of the inner shaft 12 that protrudes from the drive unit; that is, as shown in Figs. 1 to 3, the outer shaft 11 is a hollow shaft, and the inner shaft 12 protrudes from the end of the hollow outer shaft 11 by a certain length. Of course, as shown in Figs. 1 to 3, the inner shaft 12 may be a hollow shaft, which not only reduces the weight of the inner shaft but also allows it to be used as a wiring shaft for a rotary joint. If necessary, the inner shaft 12 may be a solid shaft, and may be designed so that the end of the inner shaft 12 does not exceed the end of the outer shaft 11.

[0042] An end of the outer shaft 11 is connected to a first connecting shaft 61, and an end of the inner shaft 12 is connected to a second connecting shaft 62. The first connecting shaft 61 is for mounting the first magnetic disk assembly 31, and the second connecting shaft 62 is for mounting the second magnetic disk assembly 32.

[0043] Hereinafter, a mounting structure for monitoring the drive shaft and output shaft of a rotary joint by mounting the encoder assembly 30 using the first connecting shaft 61 and the second connecting shaft 62 will be described in detail with reference to Figs.

[0044] The first connecting shaft 61 is a hollow shaft, and the second connecting shaft 62 is also a hollow shaft, and the outer diameter of the second connecting shaft 62 is smaller than the inner diameter of the first connecting shaft 61 at any position in the axial direction, i.e., the first connecting shaft 61 is located radially outward of the second connecting shaft 62. In other words, the second connecting shaft 62 is located in the hollow portion of the first connecting shaft 61 and is surrounded by the hollow first connecting shaft 61, and the two are spaced apart in the radial direction.

[0045] The first connecting shaft 61 has a first end fixedly connected to an end of the outer shaft 11 and a second end for mounting the first magnetic disk assembly 31. The second connecting shaft 62 has a first end fixedly connected to an end of the inner shaft 12 and a second end for mounting the second magnetic disk assembly 32. The first connecting shaft 61 and the outer shaft 11 may be connected by an interference fit, and the second connecting shaft 62 and the inner shaft 12 may be connected by an interference fit. Also, 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, if necessary.

[0046] As a result, the first connecting shaft 61, the outer shaft 11 and the first magnetic disk assembly 31 rotate synchronously, and the rotation speed of the first magnetic disk assembly 31 is the rotation speed of the drive shaft of the rotary joint, and the second connecting shaft 62, the inner shaft 12 and the second magnetic disk assembly 32 rotate synchronously, and the rotation speed of the second magnetic disk assembly 32 is the rotation speed of the output shaft of the rotary joint.

[0047] The bearing 70 is, for example, a deep groove ball bearing, and is mounted between the first connecting shaft 61 and the second connecting shaft 62. The outer ring of the bearing 70 contacts the inner surface of the first connecting shaft 61, and the inner ring of the bearing 70 contacts the outer surface of the second connecting shaft 62. In one embodiment of the present application, the bearing 70 is mounted on the second end of the first connecting shaft 61, one end face of which is flush with the end face of the second end of the first connecting shaft 61, and the other end abuts against a bearing positioning shoulder 623 formed on the outer surface of the second connecting shaft 62. A bearing positioning shoulder 613 may be formed on the inner surface of the first connecting shaft 61. In order to strengthen the connection between the bearing 70 and the first connecting shaft 61 and the second connecting shaft 62, an adhesive, for example, adhesive 609, may be applied between the first connecting shaft 61 and the outer ring of the bearing, and between the second connecting shaft 62 and the inner ring of the bearing 70. In order to provide a strong attachment, the connection between the bearing 70 and the first connecting shaft 61 and the second connecting shaft 62 is preferably an interference fit connection.

[0048] 1 to 3, a first connection positioning shoulder 611 for determining the attachment position of the first connecting shaft 61 relative to the outer shaft 11 is further formed on the inner peripheral surface of the first end of the first connecting shaft 61, and a second connection positioning shoulder 621 for determining the attachment position of the second connecting shaft 62 relative to the inner shaft 12 is further formed on the outer peripheral surface or end face of the first end of the second connecting shaft 62. As shown in FIGS. 1 and 2, when the first connecting shaft 61 is attached at a predetermined position, the end of the outer shaft 11 abuts against the first connection positioning shoulder 611, and when the second connecting shaft 62 is attached at a predetermined position, the end of the inner shaft 12 abuts against the second connection positioning shoulder 621.

[0049] However, the present application is not limited thereto, and when the sizes of the outer shaft 11 and the inner shaft 12 are appropriate, the first connection positioning shoulder portion 611 may be formed on the outer peripheral surface of the first connecting shaft 61, and the second connection positioning shoulder portion 621 may be formed on the inner peripheral surface of the second connecting shaft 62.

[0050] If the internal space of the rotary joint is sufficient, an additional module positioning shoulder 612 may be formed on the outer circumferential surface of the first connecting shaft 61. For example, a brake module can be attached to the outer circumferential surface of the first connecting shaft 61 using the additional module positioning shoulder 612. In one embodiment, the brake module can be attached between the additional module positioning shoulder 612 and the encoder assembly 30 to brake the outer shaft 11.

[0051] 1 to 5, the second connection shaft 62 is a hollow shaft, and the hollow portion is for passing wires through, so the second connection shaft 62 can be a wire-passing shaft of the joint. If the wires in the joint do not need to pass through the second connection shaft 62, the second connection shaft 62 may be a solid shaft. In the embodiments of the present application, the second connection shaft 62 may not be used for outputting torque, but may be used only for auxiliary measurement of the rotation speed of the rotating shaft of the transmission device, or may be a wire-passing shaft.

[0052] In addition, an auxiliary removal shoulder 622 may be formed on the inner peripheral surface of the second connecting shaft 62. The auxiliary removal shoulder 622 is intended to assist the separation operation of the second connecting shaft 62 and the inner shaft 12. Specifically, a stepped shaft dedicated to removal is inserted from one side of the first end of the second connecting shaft 62 and brought into contact with the auxiliary removal shoulder 622, and the second connecting shaft 62 can be separated from the inner shaft 12 by pushing the second connecting shaft 62.

[0053] The first connecting shaft 61 may be driven by a motor of a driving device to rotate, may be used as a driving shaft of a joint, may be connected to the driving shaft of a joint, or may be formed integrally with the driving shaft of a joint, i.e., the rotation speed of the first connecting shaft 61 is the rotation speed of the driving shaft of the joint. The second connecting shaft 62 may be driven by a transmission device to be connected to an output shaft of a joint or formed integrally with the output shaft of a joint. That is, the output of the transmission device may be used as an output shaft of a joint, the second connecting shaft 62 rotates in synchronization with the output shaft of a joint, and the rotation speed of the second connecting shaft 62 is the rotation speed of the output shaft of a joint. In the above embodiment, the first connecting shaft 61 may rotate in synchronization with the driving shaft of a rotating joint, and the second connecting shaft 62 may rotate in synchronization with the output shaft of a rotating joint, but the present application is not limited thereto, and if the structure of the driving device allows, the first connecting shaft 61 may rotate in synchronization with the output shaft of a rotating joint, and the second connecting shaft 62 may rotate in synchronization with the driving shaft of a rotating joint.

[0054] In some embodiments, the output shaft of the joint and the drive shaft of the joint (e.g., the motor shaft of the rotary joint) may be located on both sides of the drive device, respectively. In the embodiments shown in Figs. 1 to 5, the extension direction of the second connection shaft 62 and the first connection shaft 61 is the extension direction of the drive shaft of the joint (e.g., the motor shaft of the joint). Also, in the axial direction, the second end of the second connection shaft 62 does not exceed the second end of the first connection shaft 61. The second end of the first connection shaft 61 and the second end of the second connection shaft 62 are respectively used to mount the magnetic disk assemblies 31, 32 of the encoder assembly, so that the encoder modules or encoder assemblies mounted on the two connection shafts can be compactly mounted on the same side of the drive device along the axial direction, which is advantageous for reducing the occupied space of the encoder modules in the joint and the associated axial space. As can be understood by those skilled in the art, the associated axial space may be a necessary escape space, or may be a space left in consideration of, for example, heat dissipation problems, vibration problems, and wiring problems.

[0055] As shown in FIG. 2, at any axial position of the first connecting shaft 61 and the second connecting shaft 62, the outer diameter of the second connecting shaft 62 is smaller than the inner diameter of the first connecting shaft 61, so that the first connecting shaft 61 and the second connecting shaft 62 are radially separated from each other without direct contact with each other. This makes the rotations of the first connecting shaft 61 and the second connecting shaft 62 relatively independent, that is, 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, so that the rotation speed of the first connecting shaft 61 and the rotation speed of the second connecting shaft 62 can respectively represent the rotation speed of the drive shaft and the rotation speed of the output shaft of the joint. When the rotation speed of the first connecting shaft 61 and the rotation speed of the second connecting shaft 62 are measured by two encoder assemblies, respectively, the actual situation of the rotation speed of the drive shaft and the rotation speed of the output shaft of the joint can be accurately reflected.

[0056] 2 to 5, the rotation speed of the first connecting shaft 61 and the rotation speed of the second connecting shaft 62 respectively represent the rotation speed of the drive shaft and the rotation speed of the output shaft of the joint, but the present application is not limited thereto. That is, in the output structure of the drive device, for example, if the structure of the motor or the structure of the transmission device is permitted, the first connecting shaft 61 may 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 drive shaft of the joint (for example, the motor shaft of the joint).

[0057] As described above, in the embodiments of the present application, the transmission ratio of the transmission device in the drive mechanism may be 1 or more, or may be 1 or less. That is, the transmission device may be a reducer, a speed increaser, or a speed changer having both speed increase and speed decrease transmission capabilities, as necessary. Therefore, the ratio of the rotation speed between the drive shaft of the joint and the output shaft of the joint may be 1 or more, or may be 1 or less.

[0058] As described above, the encoder assembly 30 includes a magnetic disk assembly and a sensor assembly. A mounting structure of the encoder assembly 30 in a joint according to an embodiment of the present application will be described in detail below with reference to Figs.

[0059] As shown in FIGS. 1 to 5, the encoder assembly 30 includes a first magnetic disk assembly 31 attached to a first connecting shaft 61, and a second magnetic disk assembly 32 attached to a second connecting shaft 62. The first magnetic disk assembly 31 includes a first magnetic disk 311 and a first mounting bracket 312 to which the first magnetic disk 311 is attached. The first mounting bracket 312 is an annular member having an inner hole, and is fitted and fixed to the second end of the first connecting shaft 61 via the inner hole. To secure the attachment, it is preferable that the first mounting bracket 312 and the first connecting shaft 61 are connected by an interference fit.

[0060] The outer ring of the first magnetic disk 311 may be fixed to the annular portion of the first mounting bracket 312 by a screw or other screw fastener. Thus, when the first connecting shaft 61 rotates, the first magnetic disk assembly 31 consisting of the first mounting bracket 312 and the first magnetic 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 integrated member.

[0061] The second magnetic disk assembly 32 includes a second magnetic disk 321 and a second mounting bracket 322 to which the second magnetic disk 321 is attached. The second mounting bracket 322 is an annular member having an inner hole, and is fitted and fixed to the second end of the second connecting shaft 62 through the inner hole. In order to secure the attachment, it is preferable that the second mounting bracket 322 and the second connecting shaft 62 are connected by an interference fit. The outer ring of the second magnetic disk 321 may be fixed to the annular portion of the second mounting bracket 322 by a screw fastener such as a screw. As a result, when the second connecting shaft 62 rotates, the second magnetic disk assembly 32 consisting of the second mounting bracket 322 and the second magnetic 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 a further embodiment, the second connecting shaft 62 and the second mounting bracket 322 may be formed as an integrated member.

[0062] In this embodiment, the distance between the mounting position of the first mounting bracket 312 on the first connecting shaft 61 and the end face of the first magnetic disk 311 is greater than the distance between the position of the second mounting bracket 322 on the second connecting shaft 62 and the end face of the second magnetic disk 321. The first mounting bracket 312 may include a first magnetic disk mounting portion, a first connecting shaft mounting portion having an inner hole, and a connecting portion connecting the first and second mounting brackets. As shown in Figs. 1 to 3, the connecting portion may be formed as an inclined portion so as to secure a mounting space for the second mounting bracket 322 in the axial direction, thereby preventing interference in either the axial direction or the radial direction between the first mounting bracket 312 and the second mounting bracket 322, which would affect the rotation speed of the magnetic disk, or prevent magnetic field interference between the two magnetic disks. The inclination angle of the connecting portion may be 90 degrees or more. The connecting portion may also be formed in a curved shape.

[0063] In this embodiment, the first magnetic disk 311 and the second magnetic disk 321 are mounted to the first connecting shaft 61 and the second connecting shaft 62 via the first mounting bracket 312 and the second mounting bracket 322, respectively, but as can be understood by those skilled in the art, for example, if the size of the inner hole of the second magnetic disk 321 is appropriate, it is possible to consider directly mounting the second magnetic disk 321 to the second connecting shaft 62. That is, the form in which the first magnetic disk 311 and the second magnetic disk 321 are fixedly connected to the first connecting shaft 61 and the second connecting shaft 62, respectively, may be any mounting structure that can ensure that the first magnetic disk 311 and the second magnetic disk 321 rotate synchronously with the first connecting shaft 61 and the second connecting shaft 62, respectively, and is not limited to the above-mentioned form.

[0064] Furthermore, the flush mounting of the first magnetic disk 311 and the second magnetic disk 321 is advantageous in reducing the axial space occupied by or associated with the encoder assembly 30 in the joint. As shown in Figures 2 and 3, the first magnetic disk 311 may be located radially outboard of the second magnetic disk 321, and the first magnetic disk 311 and the second magnetic disk 321 may be radially spaced apart to avoid magnetic field interference between them that may distort the electrical signal received by the corresponding sensor assembly.

[0065] As described above, the encoder assembly 30 further includes a first sensor assembly mounted adjacent to the first magnetic disk 311 and a second sensor assembly mounted adjacent to the second magnetic disk 321. The first sensor assembly is configured to detect the rotational motion of the first magnetic disk 311, and the second sensor assembly is configured to detect the rotational motion of the second magnetic disk 321. Although not explicitly shown, 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) can face the first magnetic disk 311, and the second sensor assembly (particularly, the sensor of the second sensor assembly) can face the second magnetic disk 321. The first sensor assembly generates a digital signal related to the rotation speed of the first connecting shaft 61 based on an electrical signal generated by the rotation of the first magnetic disk 311, and the second sensor assembly generates a digital signal related to the rotation speed of the second connecting shaft 62 based on an electrical signal generated by the rotation of the second magnetic disk 321. A control device for at least one of the joint, the robot arm, and the robot receives these digital signals from the first sensor assembly and the second sensor assembly, and can provide feedback control or adjustment control to the drive device of the joint as necessary, thereby accurately controlling the specific movement of the joint and the robot arm or robot having the joint.

[0066] In the above embodiment, the first sensor assembly and the second sensor assembly are mounted on the same PCB circuit board 50, which not only improves the circuit integration and saves the occupied space and escape space of the PCB circuit board, but also reduces heat dissipation problems, reduces the length of wiring, and simplifies wiring connections.

[0067] As shown in FIG. 1 and FIG. 2, the PCB circuit board 50 is attached in parallel to the first magnetic disk 311 and the second magnetic disk 321, and is fixedly connected to one end of the joint housing through the connection assembly 40. The connection assembly 40 is interposed between one end of the joint housing and the PCB circuit board 50, one end of which is connected to one end of the joint housing and the other end of which is connected to the PCB circuit board 50, thereby maintaining a certain distance between the PCB circuit board 50 and one end of the joint housing. The certain distance is slightly larger than the designed overhang length of the first magnetic disk assembly 31 and the second magnetic disk assembly 32 from one end of the joint housing. When both of the two sensor assemblies are attached to the PCB circuit board 50, it is necessary to ensure a suitable gap between the end faces of the first magnetic disk assembly 31 and the second magnetic disk assembly 32 and the sensor assembly on the PCB circuit board 50 so that the first sensor assembly and the second sensor assembly can accurately detect the rotation speed of the first magnetic disk 311 and the second magnetic disk 321. In one embodiment of the present application, the designed overhang length may be greater than the thickness of the magnetic disk assembly (i.e., the total thickness of the first magnetic disk assembly and the second magnetic disk assembly). In the present application, the thickness of the magnetic disk assembly may refer to the distance between the magnetic disk surface of the magnetic disk assembly and the rear surface of its mounting bracket, and the magnetic disk assembly can be removed by clamping the thickness of the magnetic disk assembly. In other words, the thickness of the magnetic disk assembly is the thickness that can be clamped at the outer periphery of the magnetic disk assembly. As shown in FIG. 2, in the present application, for a magnetic disk assembly including both the first magnetic disk assembly 31 and the second magnetic disk assembly 32 arranged flush with each other, the thickness of the magnetic disk assembly refers to the thickness of the first magnetic disk assembly 31 located radially outward.

[0068] When mounting the first magnetic disk assembly 31 and the second magnetic disk assembly 32, first, the first connecting shaft 61 is mounted on the outer shaft 11 so that the end of the outer shaft 11 abuts against the first connecting position shoulder 611, then the second connecting shaft 62 is connected to the inner shaft 12 so that the end of the inner shaft 12 abuts against the second connecting position shoulder 621, then the inner ring of the bearing 70 is coated with adhesive 609 and press-fitted between the first connecting shaft 61 and the second connecting shaft 62, then the first magnetic disk 311 is mounted on the first mounting bracket 312 to form the first magnetic disk 311. The disk assembly 31 is formed, the second magnetic disk 321 is attached to the second mounting bracket 322 to form the second magnetic disk assembly 32, the first magnetic disk assembly 31 is fitted to the first connecting shaft 61, the second magnetic disk assembly 32 is fitted to the second connecting shaft 62, and then the two magnetic disk assemblies 31 and 32 are simultaneously pressed into the first connecting shaft 61 and the second connecting shaft 62 respectively connected to the inner shaft 12 and the outer shaft 11 of the driving device along the axial direction using the magnetic disk pressing jig 14 as shown in FIG. By simultaneously pressing the two magnetic disk assemblies 31 and 32 using the magnetic disk pressing jig 14, it can be ensured that the distance from the end face of the two magnetic disks (i.e., the magnetic disk surface facing the PCB circuit board 50 or the sensor assembly) to the end face of the joint housing and the coplanarity of the two magnetic disks (i.e., the magnetic disk surface) meet the requirements.

[0069] After the magnetic disk assemblies are attached at a predetermined position, the magnetic 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 connection assembly 40, and the gap between the PCB circuit board 50 and the end faces (i.e., the magnetic disk surfaces) of the two magnetic disks is adjusted. By ensuring an appropriate gap between the PCB circuit board 50 and the end faces of the two magnetic disks, each sensor assembly can accurately detect the magnetic field change caused by the rotation of the corresponding magnetic disk assembly and output a digital signal related to the number of rotations of the corresponding connection shaft, thereby obtaining the number of rotations information of the drive shaft of the rotary joint and the output shaft of the rotary joint. After the encoder module is attached at a predetermined position, as shown in FIG. 1 and FIG. 2, the encoder module or encoder assembly may be attached in a state of overhanging by a predetermined length from one end of the joint housing so as to facilitate subsequent removal of the encoder module.

[0070] The connection assembly 40 may include spacer pillars, such as cylindrical or hexagonal spacer pillars, and each end of each spacer pillar may be formed with a female thread or a male thread. The spacer pillar may have one end screwed to one end of the joint housing, and the other end screwed to the PCB circuit board 50. More specifically, the spacer pillar may have one end connected to at least one of the end face, inner wall or outer wall of one end of the joint housing, and the other end screwed to the PCB circuit board 50 by another screw, bolt or nut. When one end of the spacer pillar is connected to the inner wall or outer wall of one end of the joint housing, a corresponding inner or outer protrusion may be formed on the inner or outer wall of the joint housing. The inner or outer protrusion may have a through hole or a screw hole for connection. The connection assemblies 40 are at least two, for example, three, four, five, six or more. The number of connection assemblies 40 can be determined according to the size of the joint housing, the shape and weight of the PCB circuit board, and the specifications of the spacer pillars.

[0071] The connection assembly 40 is not limited to a spacer post having a female thread or a male thread at both ends. For example, the connection assembly 40 may further include at least one boss that protrudes axially from at least one of the inner wall, the outer wall, and / or the end face of one end of the joint housing, and a screw fastener that is screwed into the boss. The boss protrudes a predetermined distance from one end of the joint housing and is integrally formed with the joint housing, and a screw hole is formed in the boss. The PCB circuit board 50 is connected by coupling the screw fastener with the boss so that the PCB circuit board 50 is fixed to the joint housing at a predetermined distance from the one end of the joint housing, and is fixedly connected to the joint housing.

[0072] As shown in FIG. 2, the PCB circuit board 50 has a central hole 51 for passing a cable or a wire. The end of the second connection shaft 62 does not extend to the PCB circuit board 50 or does not penetrate the PCB circuit board 50, but is spaced apart from the PCB circuit board 50 in the axial direction of the driving device and is flush with the magnetic disk surface of the magnetic disk assembly. As can be seen from the above description, the first mounting bracket 312 and the second mounting bracket 322 are located on one side of the first magnetic disk and the second magnetic disk and are connected thereto without any gap in the axial direction, and the PCB circuit board 50 is located on the other side of the first magnetic disk and the second magnetic disk and is spaced apart from the first magnetic disk and the second magnetic disk. By compactly arranging the PCB circuit board and the first magnetic disk assembly and the second magnetic disk assembly attached to the first connection shaft 61 and the second connection shaft 62, respectively, the axial space occupied in the rotary joint of the encoder module can be effectively reduced.

[0073] In one embodiment, the connection assembly 40 may be a spacer post or a boss and screw fastener, and two kinds of connection assemblies may be simultaneously applied to connect the PCB circuit board 50 and one end of the joint housing 20 in one joint.

[0074] To facilitate installation and removal, the spacer post may be a hexagonal stud with a male thread at one end and a female thread at the other end. The hexagonal stud may be screwed into the end face of one end of the joint housing at one end, and may be screwed through a through hole penetrating the PCB circuit board 50 at the other end. By changing the screw-in depth of one end of the hexagonal stud, the distance between the PCB circuit board 50 and one end of the joint housing can be adjusted to adjust the gap between the magnetic disk assembly and the sensor assembly.

[0075] In the above embodiment, when removing the encoder module, first, the PCB circuit board 50 is removed, and then the first magnetic disk assembly 31 and the second magnetic disk assembly 32 can be simultaneously removed from the first connecting shaft 61 and the second connecting shaft 62, respectively, using a magnetic disk removal jig. Then, the second connecting shaft 62 and the bearing 70 are simultaneously removed using the stepped shaft described above, and finally the first connecting shaft 61 is removed.

[0076] In the embodiment of the present application, a step (i.e., a shoulder) for mounting a bearing is formed at the end of the first connecting shaft and the second connecting shaft adjacent to the magnetic disk mounting bracket, thereby ensuring the coaxiality of the two elongated shafts protruding from the driving device in the joint housing and the rigid support capacity for the two shafts, and not hindering the independent rotation of the two shafts, ensuring the concentric mounting of the encoder module with the driving shaft and the output shaft of the rotary joint, and avoiding the occurrence of asymmetry or angle error. The above structure further improves the robustness of the encoder module against shock and vibration. At the same time, the end faces of the second ends of the two connecting shafts are flush with the corresponding magnetic disk surfaces, thereby maximally shortening the length of the elongated shafts, reducing the processing difficulty of the product, and simplifying the installation and adjustment of the encoder module.

[0077] In addition, the mounting of the encoder module bearings, input magnetic disk bracket, and output magnetic disk bracket can all be achieved by combining stepped shaft positioning and interference fitting, as well as by using an adhesive application mounting method, simplifying the assembly structure of the encoder module and making installation and removal even easier.

[0078] In the embodiments of the present application, the specific position of one end of the joint housing to which the connection assembly is connected can be reasonably 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 magnetic disk assembly in the encoder assembly, and is not limited to a fixed position.

[0079] According to at least one embodiment of the present application, the connection method between the PCB circuit board and the joint housing not only facilitates the installation and removal of the PCB circuit board and the encoder assembly, but also facilitates the adjustment of the gap between the sensor assembly on the PCB circuit board and the end surface of the magnetic disk in the encoder assembly, further improving the assembly efficiency of the joint.

[0080] In addition, the input and output magnetic disks (i.e., the first and second magnetic disks) in the encoder module of the joint are arranged on the same end surface, and only one PCB circuit board is used, which fully utilizes the radial space, greatly saves the axial space of the joint, improves the system integration, and contributes to the miniaturization of the product design. At the same time, the two magnetic disks can be installed, adjusted, and removed at the same time using the same tool, improving the installation accuracy and efficiency.

[0081] In addition, by concentrating and arranging 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 magnetic disk and the sensor on the PCB circuit board is further simplified (because the requirement for the gap between the magnetic disk and the sensor is very strict). The above arrangement method allows for accurate press-fitting using a magnetic disk mounting jig, reducing the step of adjusting the gap, and such an encoder module structure is more suitable for harsh industrial environments with extreme temperatures, humidity, and particle contamination.

[0082] In the description of the present application, the orientations or positional relationships indicated by terms such as "center," "longitudinal," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and the like are orientations or positional relationships shown in the drawings, and are used only to facilitate or simplify the description of the present application, and are not intended to represent or imply that the devices or parts shown necessarily have a specific orientation or a specific oriented structure and operation, and therefore should not be construed as limiting the present application.

[0083] Additionally, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply a relative importance or to imply a number of the technical features depicted. Thus, a feature qualified as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of this application, unless otherwise clearly and specifically limited, "plurality" means at least two, e.g., two, three, etc.

[0084] In this application, unless otherwise clearly specified and limited, the terms "attached", "coupled", "connected" and the like should be understood in a broad sense, for example, may be a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, an internal communication between two members, or an interactive relationship between two members. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific situation.

[0085] In this application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include direct contact between the first feature and the second feature, or indirect contact between the first feature and the second feature via an intermediate medium. Furthermore, a first feature being "above," "above," and "on the upper surface" of a second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the horizontal height of the first feature is higher than that of the second feature. A first feature being "below," "below," and "on the lower surface" of a second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the horizontal height of the first feature is lower than that of the second feature.

[0086] It should be noted that when an element is referred to as being "fixed" or "mounted" on another element, it may be directly on the other element, or there may be intervening elements present. When an element is referred to as being "connected" to another element, the element may be directly connected to the other element, but there may also be intervening elements present between them. The terms "vertical," "horizontal," "up," "down," "left," "right," and similar terms used herein are for illustrative purposes only and do not represent the only embodiments.

[0087] The technical features of the above-mentioned embodiments can be combined in any combination. For the sake of brevity, all possible combinations of the technical features of the above-mentioned embodiments are not described, but all such combinations should be considered to be within the scope of the present specification.

[0088] The above examples only describe some embodiments of the present application, and although the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent of the present application. It should be noted that those skilled in the art may make various modifications and improvements to the present application without departing from the spirit of the present application, and both of these modifications and improvements are within the scope of protection of the present application. Therefore, the scope of protection of the patent of the present application should be based on the scope of the attached claims.

Claims

1. a joint housing, a drive mechanism mounted within the joint housing, and an encoder module mounted to the drive mechanism; The drive device has an inner shaft and an outer shaft surrounding the inner shaft and radially spaced from the inner shaft, The encoder module includes: a first magnetic disk assembly configured to rotate synchronously with the outer shaft; a second magnetic disk assembly configured to rotate synchronously with the inner shaft; a first sensor assembly disposed adjacent to the first magnetic disk assembly and configured to detect movement of a magnetic disk of the first magnetic disk assembly; a second sensor assembly disposed adjacent to the second magnetic disk assembly and configured to detect movement of a magnetic disk of the second magnetic disk assembly; A rotary joint, wherein a magnetic disk surface of the first magnetic disk assembly and a magnetic disk surface of the second magnetic disk assembly are arranged flush with each other and are spaced apart from each other in a radial direction by at least a predetermined distance.

2. The encoder module includes: a first connecting shaft having a first end and a second end, the first end of the first connecting shaft being connected to a terminal end of the outer shaft; a second connecting shaft having a first end and a second end, the first end of the second connecting shaft being fixedly connected to the inner shaft; a bearing mounted between the first connecting shaft and the second connecting shaft, the first magnetic disk assembly is fixed to the first connecting shaft; The rotary joint according to claim 1 , wherein the second magnetic disk assembly is fixed to the second connecting shaft.

3. 3. The rotary joint according to claim 2, wherein the first connecting shaft is a hollow shaft and has a first bearing positioning shoulder formed on its inner circumferential surface, and / or the second connecting shaft has a second bearing positioning shoulder formed on its outer circumferential surface.

4. 4. The rotary joint according to claim 3, wherein a first connection positioning shoulder for positioning an attachment position of the first connection shaft relative to the outer shaft is formed on an inner circumferential surface or an outer circumferential surface of the first end of the first connection shaft.

5. The rotary joint according to claim 3 , wherein an additional module positioning shoulder is formed on an outer circumferential surface of the first connecting shaft.

6. 4. The rotary joint according to claim 3, wherein a second connection positioning shoulder for positioning an attachment position of the second connection shaft relative to the inner shaft is formed on an outer circumferential surface of the second connection shaft or on an end face of the first end.

7. 4. The rotary joint according to claim 3, wherein the inner shaft is a hollow shaft and protrudes from the outer shaft by a certain length, and the second connection shaft is a hollow shaft, and a second connection positioning shoulder for positioning an attachment position of the second connection shaft with respect to the inner shaft and / or a removal auxiliary shoulder for separating the second connection shaft from the inner shaft is formed on the inner circumferential surface.

8. 3. The rotary joint according to claim 2, wherein an end face of a second end of the first connection shaft is flush with an outer end face of the bearing, and an end face of the second end of the second connection shaft is flush with a magnetic disk surface of the first magnetic disk assembly and a magnetic disk surface of the second magnetic disk assembly.

9. The rotary joint according to claim 2 , wherein the bearing is adhered to at least one of the first connection shaft and the second connection shaft by an adhesive.

10. 2. The rotary joint of claim 1, wherein the encoder module structure further includes a PCB circuit board on which the first sensor assembly and the second sensor assembly are mounted, the PCB circuit board being parallel to and spaced apart from a magnetic disk surface of the first magnetic disk assembly and a magnetic disk surface of the second magnetic disk assembly.

11. 11. The rotating joint according to claim 10, wherein the PCB circuit board is fixed to at least one of an inner wall, an outer wall, and an end face of one end of the joint housing, and the PCB circuit board is spaced a predetermined distance from the one end of the joint housing.

12. The rotary joint according to claim 11 , wherein the predetermined distance is greater than at least a total thickness of the first magnetic disk module and the second magnetic disk module.

13. 12. The rotating joint according to claim 11, wherein the PCB circuit board is directly fixed to the joint housing via at least one spacer post, and each end of each spacer post is formed with an internal or external thread.

14. 12. The rotating joint according to claim 11, wherein the joint housing includes at least one boss provided on at least one of an inner wall, an outer wall and / or an end face of the one end of the joint housing, and a screw fastener screwed into the boss, the one boss protruding a predetermined distance from the one end of the joint housing, a screw hole is formed in each boss, and the PCB circuit board is connected by coupling the screw fastener with the boss and fixedly connected to the joint housing.

15. The rotary joint of claim 11, wherein the PCB circuit board has a central hole for passing a cable therethrough.

16. 11. A rotary joint according to claim 10, wherein the first sensor assembly and / or the second sensor assembly comprises a sensor, which is a Hall sensor or a giant magnetoresistance sensor, and a conditioning circuit integrated on a chip.

17. the first magnetic disk assembly includes a first magnetic disk and a first mounting bracket supporting the first magnetic disk, the first mounting bracket being attached to the second end of the first connecting shaft; 3. The rotary joint of claim 2, wherein the second magnetic disk assembly includes a second magnetic disk and a second mounting bracket supporting the second magnetic disk, the second mounting bracket being attached to the second end of the second connecting shaft.

18. 2. The rotary joint according to claim 1, wherein the drive device includes a motor and a transmission device driven by the motor, the motor drives one of the inner shaft and the outer shaft, and the transmission device drives the other of the outer shaft and the inner shaft, the drive device is mounted within the joint housing, and the encoder module is detached from the drive device by extending a predetermined length from one end of the joint housing.

19. The revolute joint of claim 1 , further comprising a controller configured to adjust operation of the drive mechanism based on signals output from the first sensor assembly and the second sensor assembly.

20. An apparatus comprising at least one revolute joint according to any one of the preceding claims.

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