Mechanical arm joint

Abstract

The invention discloses a mechanical arm joint which comprises a base, a turbine clutch assembly, a driving plate and a motor. The turbine clutch assembly is arranged in the base, an output shaft of the turbine clutch assembly is installed on the base and the base end cover through bearings, an encoder sensing element is arranged at the end, corresponding to the driving plate, of the output shaft, and the turbine clutch assembly is meshed with the worm. The driving plate is mounted on the base end cover, and an encoder corresponding to the encoder sensing element is arranged on the driving plate; the motor is connected with the worm in a driving mode, the worm is installed on the base through a bearing, the motor drives the worm to rotate, the worm drives the turbine clutch assembly, an output shaft of the turbine clutch assembly rotates, and the encoder senses position changes of the output shaft. The clutch can automatically slip when encountering certain resistance, and can continue to run according to a formulated route after the resistance disappears, so that the safety of operators is protected; the clutch has an unlocking mode, dragging teaching is light and flexible, and the clutch and the motor do not interfere with each other.

Description

Technical Field

[0001] The invention relates to a robot mechanical arm, in particular to a mechanical arm joint. Background Art

[0002] With the advancement of science and technology, robots have begun to enter the civilian industry from the industrial sector. The robot arm is the most important part of the robot, and the joint of the robot arm is the core of the robot arm. At present, the design framework of the robot arm joint is basically a combination of a frameless torque motor with a harmonic reducer or a cycloidal pinwheel reducer, and then with an encoder to achieve closed-loop control. The advantages of this structure are high precision, large load, and strong rigidity, but its disadvantages are: 1. When the machine interacts with people, the rigidity is too strong. Once the machine comes into contact with people, it will seriously collide with the operator, posing a safety hazard to the human body. 2. Conventional robot arm drag teaching (drag teaching means that the operator can directly drag the robot joints to move to the ideal posture and record it. It is the simplest way to operate the robot arm.) The conventional robot arm drag teaching is achieved by driving the motor to rotate in the direction of dragging through current loop feedback. The arm is connected to the motor part, and the drag teaching is slow and bulky. However, there are almost no worm gear solutions used in collaborative robots on the market, because the worm gear is self-locking, does not have the function of drag teaching, and is also more dangerous when interacting with people. Summary of the invention

[0003] In response to the above-mentioned existing technical problems, the present invention provides a robotic arm joint, which can automatically slip when encountering a certain resistance, and can continue to operate according to the set route after the resistance disappears, thereby protecting the safety of the operator; the clutch has an unlocking mode, and the dragging teaching is light and flexible, and does not interfere with the motor.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions: a mechanical arm joint, comprising a base, a turbine clutch assembly, a drive plate and a motor; the turbine clutch assembly is arranged in the base, the output shaft of the turbine clutch assembly is installed on the base and the base end cover through a bearing, an encoder sensing element is provided at one end of the output shaft corresponding to the drive plate, and the turbine clutch assembly is engaged with a worm gear; the drive plate is installed on the base end cover, and an encoder corresponding to the encoder sensing element is provided on the drive plate; the motor drives the worm gear connected to the worm gear, and the worm gear is installed on the base through a bearing, the motor drives the worm gear to rotate, the worm gear drives the turbine clutch assembly, the output shaft of the turbine clutch assembly rotates, and the encoder senses its position change.

[0005] The present invention further provides that the turbine clutch assembly comprises a coil contact circuit board, a compression spring, a turbine, a coil, a magnetic attraction sheet, a fixing sheet, an end fixing sheet, an output shaft and a movable sheet; an annular groove is provided inside the turbine, and a wire outlet hole is reserved, the coil is buried in the annular groove of the turbine, the wire is led out from the wire outlet and connected to the coil contact circuit board; the coil contact circuit board is fixed on one side of the turbine, a slip ring circuit board is correspondingly provided on the end cover of the base, a plurality of elastic conductive contacts are provided on the coil contact circuit board, the contacts are divided into an inner ring and an outer ring, corresponding to the metal slip ring on the slip ring circuit board on the end cover of the base, the contacts of the coil contact circuit board contact the metal slip ring on the slip ring circuit board, and then the slip ring circuit board is connected to the coil control port through a lead, and when the turbine rotates, the coil rotates along with it; a plurality of threaded holes and threaded holes with steps are provided on the end face edge of the turbine, wherein a compression spring is installed inside the threaded hole with steps, and the compression spring is The pressure is adjusted by the tightening screw; the edges of the magnetic sheet, the fixed sheet and the end fixed sheet have holes corresponding to the fixing screws, and the magnetic sheet, the fixed sheet and the end fixed sheet are fixed to the other side of the turbine by the fixing screws, the front end of the fixing screw is a thread, the middle part is a smooth rod step, and the rear end is a nut. The notches on the edges of the magnetic sheet, the fixed sheet and the end fixed sheet are as large as the smooth rod step in the middle of the fixing screw, and can slide axially on the fixing screw; the movable sheet is arranged between the magnetic sheet, the fixed sheet and the end fixed sheet, and a certain gap is left between the magnetic sheet and the turbine. Under the action of the compression spring, the magnetic sheet moves away from the turbine and squeezes the movable sheet and the fixed sheet, so that friction resistance is generated between the sheets; the output shaft is arranged at the center of the turbine and each sheet, and the turbine, the fixed sheet, the end fixed sheet and the magnetic sheet can rotate freely around the output shaft, and the movable sheet rotates with the output shaft; through the action of the compression spring, the friction between the sheets will cause the turbine clutch assembly to rotate as a whole.

[0006] The present invention further provides that the length of the polished rod step in the middle of the fixing screw is slightly greater than the sum of the thicknesses of all magnetic sheets, the fixing sheet, the end fixing sheet and the movable sheet.

[0007] According to the present invention, the output shaft is a hollow circular tube with a step in the middle corresponding to the position of the center hole of each plate; the holes in the center of the fixed plate, the end fixed plate and the magnetic plate are equal to the diameter of the circumscribed circle of the step, and the inner hole of the turbine is equal to the outer diameter of the output shaft circular tube.

[0008] According to a further aspect of the present invention, the turbine and the magnetic attraction sheet are both made of strong magnetic materials, and the movable sheet, the fixed sheet and the end fixed sheet are made of weak magnetic materials.

[0009] Furthermore, in the present invention, one side of the base is a wire bin end cover, and the connecting wire of the coil passes through the coil contact circuit board and the slip ring circuit board, and is then connected to the outside through the wire bin end cover.

[0010] Furthermore, the present invention, the motor is mounted on a motor fixing seat, and the motor output shaft is connected to a coupling; the worm is fixed by a fixing nut, and the fixing nut is a hollow structure, through which the coupling passes and is connected to the worm input shaft.

[0011] According to a further aspect of the present invention, the encoder is fixed between the output shaft and the base.

[0012] According to a further aspect of the present invention, the encoder sensing element is a magnet.

[0013] The beneficial effects of adopting the above technical solution are: the arm of the present invention is rigidly connected to the turbine output shaft. When the arm encounters a large resistance (greater than the total friction of the clutch after conversion), the movable piece slips, the turbine rotates freely, and the turbine output shaft and the arm remain motionless. This automatic slipping method when encountering a certain resistance can protect personnel safety to the greatest extent during human-computer interaction; since the encoder sensing element is installed on the turbine output shaft, the free rotation of the turbine does not affect the position sensing of the encoder. Therefore, when the resistance disappears, the arm can still reach the specified angle according to the original motion plan, and can continue to operate according to the planned route after the resistance disappears.

[0014] When the robot arm needs to be dragged for teaching, the electromagnetic coil is energized, the magnetic sheet is separated from the other sheets, the clutch assembly is unlocked, the worm gear remains stationary, the arm can be dragged freely, and the encoder senses and records the position change. After breaking away from the obstruction of the worm gear clutch, the arm and the motor part do not interfere with each other, and the drag teaching process is light and flexible. After the recording is completed, the coil is powered off, the magnetic sheet absorbs the fixed sheet, and the worm gear resumes driving, which can drive the arm to move according to the previously recorded position. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the component disassembly of the present invention;

[0016] Figure 2 It is a schematic diagram of the external state of the present invention;

[0017] Figure 3 It is a schematic structural diagram of a turbine clutch assembly of the present invention;

[0018] Figure 4 It is a schematic diagram of the magnetic attraction sheet, the fixing sheet and the end fixing sheet of the present invention;

[0019] Figure 5 It is a schematic diagram of the movable sheet of the present invention;

[0020] Figure 6 is a cross-sectional view of the present invention;

[0021] In the figure: 1, base, 2, bearing, 3, turbine clutch assembly, 4, slip ring circuit board, 5, base end cover, 6, drive plate, 7, worm rod, 8, fixing nut, 9, coupling, 10, motor fixing seat, 11, motor, 12, wire bin end cover, 301, coil contact circuit board, 302, clamping screw, 303, compression spring, 304, turbine, 305, coil, 306, magnetic sheet, 307, fixing sheet, 308, end fixing sheet, 309, output shaft, 310, fixing screw, 311, movable sheet. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] An embodiment of the present invention: Figure 1 and Figure 2 As shown, a mechanical arm joint includes a base 1, a turbine clutch assembly 3, a drive plate 6 and a motor 11; the turbine clutch assembly 3 is installed in the base 1 through two bearings 2, the output shaft 309 of the turbine clutch assembly 3 is installed on the base 1 and the base end cover 5 through the bearing 2, an encoder sensing element is fixed to one end of the output shaft 309 corresponding to the drive plate 6, and the turbine clutch assembly 3 is meshed with the worm 7; the drive plate 6 is installed on the base end cover 5, and an encoder corresponding to the encoder sensing element is provided on the drive plate 6; the motor 11 drives the connected worm 7, the worm 7 is installed on the base 1 through the bearing 2, the motor 11 drives the worm 7 to rotate, the worm 7 drives the turbine clutch assembly 3, the output shaft 309 of the turbine clutch assembly 3 rotates, and the encoder senses its position change. When the turbine clutch assembly 3 encounters a certain resistance, the clutch realizes automatic slipping, and after the resistance disappears, it can continue to run according to the set route to protect the safety of the operator; the turbine clutch assembly 3 has an unlocking mode, and the dragging teaching is light and flexible, and does not interfere with the motor.

[0025] In other specific embodiments of the present invention, the rest is the same as the above embodiment, except that Figure 3 , Figure 4 and Figure 5As shown, the turbine clutch assembly 3 includes a coil contact circuit board 301, a compression spring 303, a turbine 304, a coil 305, a magnetic sheet 306, a fixing sheet 307, an end fixing sheet 308, an output shaft 309 and a movable sheet 311; the turbine 304 has an annular groove inside and a wire outlet hole, the coil 305 is buried in the annular groove of the turbine 304, the wire is led out from the wire outlet and connected to the coil contact circuit board 301; the coil contact circuit board 301 is fixed on one side of the turbine 304, and the base A slip ring circuit board 4 is correspondingly arranged on the end cover 5. A plurality of elastic conductive contacts are arranged on the coil contact circuit board 301. The contacts are divided into an inner circle and an outer circle, corresponding to the metal slip ring on the slip ring circuit board 4 on the base end cover 5. The contacts of the coil contact circuit board 301 contact the metal slip ring on the slip ring circuit board, and then the slip ring circuit board 4 is connected to the control port of the coil 305 through a lead wire. When the turbine 304 rotates, the coil 305 rotates along with it. The cooperation between the coil contact circuit board and the slip ring circuit board can prevent the wire of the coil from being torn off after multiple rotations. The end face edge of the turbine 304 is provided with a plurality of threaded holes and threaded holes with steps, wherein a compression spring 303 is installed inside the threaded hole with steps, and the pressure of the compression spring 303 is adjusted by the clamping screw 302; the edges of the magnetic sheet 306, the fixing sheet 307 and the end fixing sheet 308 have holes corresponding to the fixing screws, and the magnetic sheet 306, the fixing sheet 307 and the end fixing sheet 308 are fixed to the other side of the turbine 304 by the fixing screw 310, and the front end of the fixing screw 310 is a thread, the middle part is a polished rod step, and the rear end is a nut, and the notches on the edges of the magnetic sheet 306, the fixing sheet 307 and the end fixing sheet 308 are as large as the polished rod step in the middle of the fixing screw 310, so that they can be axially moved on the fixing screw 310 Sliding; the movable sheet 311 is arranged between the magnetic sheet 306, the fixed sheet 307, and the end fixed sheet 308, and a certain gap is left between the magnetic sheet 306 and the turbine 304. Under the action of the compression spring 303, the magnetic sheet 306 moves away from the turbine 304 and squeezes the movable sheet 311 and the fixed sheet 307, so that a large friction resistance is generated between the sheets; the output shaft 309 is arranged on the turbine 304 and the center of each sheet, the turbine 304, the fixed sheet 307, the end fixed sheet 308, and the magnetic sheet 306 can rotate freely around the output shaft 309, and the movable sheet 311 rotates with the output shaft 309; through the action of the compression spring 303, the friction between the sheets will cause the turbine clutch assembly to rotate as a whole.

[0026] In combination with the above embodiments, the working principle of the present invention is as follows Figure 3 and Figure 6As shown, under normal circumstances, the turbine clutch assembly 3 as a whole rotates together under the drive of the worm 7, and the output shaft 309 outputs torque. When the external force on the output shaft 309 is greater than the total friction of the clutch, the movable sheet 311 slips, the turbine 304 rotates freely, and the output shaft 309 follows the external force, that is, the arm part automatically slips to protect the safety of the operator. Since the encoder sensing element is installed on the turbine output shaft, the free rotation of the turbine does not affect the position sensing of the encoder. When the resistance disappears, the external force on the output shaft 309 is less than the total friction of the clutch, and the motor resumes control of the output shaft 309. The arm can still reach the specified angle according to the original motion plan and continue to run according to the set route. When the robot arm needs to be dragged for teaching, the coil 305 is energized, the turbine 304 and the magnetic sheet 306 are both strong magnetic materials, and the movable sheet 311, the fixed sheet 307 and the end fixed sheet 308 are weak magnetic materials. The magnetic attraction piece 306 is subjected to a magnetic force greater than the elastic force of the compression spring 303, and will be sucked back to fit the turbine 304. Since the length of the light rod step in the middle of the fixing screw 311 is slightly larger, all the pieces are no longer pressed tightly, the friction disappears, and the output shaft 309 can rotate freely, that is, the arm part automatically slips, allowing the turbine clutch assembly 3 to be unlocked, the turbine 304 and the worm 7 to remain stationary, the arm can be dragged freely, and the position change is sensed and recorded by the encoder; after the recording is completed, the coil 305 is powered off, and the magnetic attraction piece 306 is compressed by the elastic force of the compression spring 303 to contact the fixed piece 307, and the turbine 304 and the worm 7 resume driving, which can drive the arm to move to the previously recorded position.

[0027] This multi-piece clutch structure can output greater friction as much as possible under smaller spring pressure. From the friction formula f=μN, it can be seen that the magnitude of friction depends only on the friction coefficient and the normal pressure. When the spring applies pressure to the magnetic suction piece 306, it can be seen from Newton's third law that each subsequent piece receives equal action and reaction force, so there is an equal friction in each friction pair, and the total friction is equal to the sum of the spring elastic force × friction coefficient × the number of friction pairs. Therefore, the friction will increase accordingly for each additional movable piece 311 and fixed piece 307, and can be adjusted according to the actual situation.

[0028] In other specific embodiments of the present invention, the rest is the same as the above embodiment, except that Figure 3 As shown, the length of the middle polished rod step of the fixing screw 310 is slightly larger than the sum of the thicknesses of all the magnetic sheets 306 , the fixing sheet 307 , the end fixing sheet 308 and the movable sheet 311 , ensuring a certain gap between the magnetic sheet 306 and the turbine 304 .

[0029] In other specific embodiments of the present invention, the rest is the same as the above embodiment, except that Figure 3As shown, the output shaft 309 is a hollow circular tube with a step in the middle corresponding to the position of the center hole of each sheet; the holes in the center of the fixed sheet 307, the end fixed sheet 308, and the magnetic sheet 306 are equal to the diameter of the circumscribed circle of the step, and the inner hole of the turbine 304 is equal to the outer diameter of the circular tube of the output shaft 309. It is ensured that the turbine 304, the fixed sheet 307, the end fixed sheet 308, and the magnetic sheet 306 can rotate freely around the output shaft 309, and the movable sheet 311 rotates with the output shaft 309.

[0030] In other specific embodiments of the present invention, the rest is the same as the above embodiment, except that Figure 1 As shown, one side of the base 1 is a wire bin end cover 12, and the connecting wire of the coil 305 is connected to the outside through the coil contact circuit board 301 and the slip ring circuit board 4, and then connected to the outside through the wire bin end cover 12, so the wiring is safe and reliable.

[0031] In other specific embodiments of the present invention, the rest is the same as the above embodiment, except that Figure 1 As shown, the motor 11 is mounted on the motor fixing seat 10, and the output shaft of the motor 11 is connected to the coupling 9; the worm 7 is fixed by a fixing nut 8, and the fixing nut 8 is a hollow structure, through which the coupling 9 passes and is connected to the worm input shaft. The coupling is safe and reliable, and is easy to assemble, disassemble and maintain.

[0032] In other specific embodiments of the present invention, the rest is the same as the above embodiment, except that Figure 1 As shown, the encoder is fixed between the output shaft 309 and the base 1, and can directly record the position change of the output shaft.

[0033] In other specific embodiments of the present invention, the rest is the same as the above embodiment, except that Figure 1 As shown, the encoder sensing element is a magnet, and of course other suitable solutions such as photoelectric sensing elements can also be used instead.

[0034] Of course, the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the main technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A robotic arm joint, characterized in that: Includes a base, a turbine clutch assembly, a drive plate and a motor; The turbine clutch assembly is arranged in the base, the output shaft of the turbine clutch assembly is mounted on the base and the base end cover through a bearing, an encoder sensing element is arranged at one end of the output shaft corresponding to the driving plate, and the turbine clutch assembly is meshed with the worm gear; The driving plate is mounted on the end cover of the base, and an encoder corresponding to the encoder sensing element is provided on the driving plate; The motor drives the worm gear, which is mounted on a base through a bearing. The motor drives the worm gear to rotate, and the worm gear drives the turbine clutch assembly. The output shaft of the turbine clutch assembly rotates, and the encoder senses its position change.

2. A mechanical arm joint according to claim 1, characterized in that: The turbine clutch assembly includes a coil contact circuit board, a compression spring, a turbine, a coil, a magnetic sheet, a fixing sheet, an end fixing sheet, an output shaft and a movable sheet; The turbine has an annular groove inside and a wire outlet hole. The coil is buried in the annular groove of the turbine, and the wire is led out from the wire outlet and connected to the coil contact circuit board. The coil contact circuit board is fixed on one side of the turbine, and a slip ring circuit board is correspondingly arranged on the base end cover. There are a number of elastic conductive contacts on the coil contact circuit board. The contacts are divided into an inner circle and an outer circle, which correspond to the metal slip ring on the slip ring circuit board on the base end cover. The contacts of the coil contact circuit board contact the metal slip ring on the slip ring circuit board, and then the slip ring circuit board is connected to the coil control port through a lead. When the turbine rotates, the coil rotates with it. The end face edge of the turbine is provided with a plurality of threaded holes and threaded holes with steps, wherein a compression spring is installed inside the threaded hole with steps, and the compression spring is adjusted in pressure by a clamping screw; the edges of the magnetic sheet, the fixed sheet and the end fixed sheet are provided with holes corresponding to the fixing screws, and the magnetic sheet, the fixed sheet and the end fixed sheet are fixed to the other side of the turbine by the fixing screws, the front end of the fixing screw is a thread, the middle part is a bare rod step, and the rear end is a nut, and the gaps at the edges of the magnetic sheet, the fixed sheet and the end fixed sheet are as large as the bare rod step in the middle of the fixing screw, and can slide axially on the fixing screw; the movable sheet is arranged between the magnetic sheet, the fixed sheet and the end fixed sheet, and a certain gap is left between the magnetic sheet and the turbine, and under the action of the compression spring, the magnetic sheet moves away from the turbine and squeezes the movable sheet and the fixed sheet, so that friction resistance is generated between the sheets; the output shaft is arranged at the center of the turbine and each sheet, and the turbine, the fixed sheet, the end fixed sheet and the magnetic sheet can rotate freely around the output shaft, and the movable sheet rotates with the output shaft; through the action of the compression spring, the friction between the sheets will cause the turbine clutch assembly to rotate as a whole.

3. A mechanical arm joint according to claim 2, characterized in that: The length of the polished rod step in the middle of the fixing screw is slightly greater than the sum of the thicknesses of all the magnetic suction plates, the fixing plates, the end fixing plates and the movable plates.

4. A mechanical arm joint according to claim 2, characterized in that: The output shaft is a hollow circular tube with a step in the middle corresponding to the position of the center hole of each plate; the holes in the center of the fixing plate, the end fixing plate and the magnetic plate are equal to the diameter of the circumscribed circle of the step, and the inner hole of the turbine is equal to the outer diameter of the output shaft circular tube.

5. A mechanical arm joint according to claim 2, characterized in that: The turbine and the magnetic attraction sheet are both made of strong magnetic materials, and the movable sheet, the fixed sheet and the end fixed sheet are made of weak magnetic materials.

6. A mechanical arm joint according to claim 2, characterized in that: One side of the base is a wire bin end cover, and the connecting wire of the coil contacts the circuit board and the slip ring circuit board through the coil, and is then connected to the outside through the wire bin end cover.

7. A mechanical arm joint according to claim 1 or 2, characterized in that: The motor is mounted on a motor fixing seat, and the motor output shaft is connected to a coupling; the worm is fixed by a fixing nut, and the fixing nut is a hollow structure, through which the coupling passes and is connected to the worm input shaft.

8. A mechanical arm joint according to claim 1 or 2, characterized in that: The encoder is fixed between the output shaft and the base.

9. A mechanical arm joint according to claim 1 or 2, characterized in that: The encoder sensing element is a magnet.

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