TWI426012B - Gear backlash adjusting mechanism and industrial robot using same - Google Patents

Description

Gear backlash adjusting device and industrial robot using the same

The invention relates to a gear backlash adjusting device and an industrial robot using the same, in particular to an adjusting device for adjusting a backlash of a spur gear and an industrial robot using the adjusting device and using a gear mechanism for transmission.

Industrial robots usually include a plurality of wrist units connected in series, and wrist units provided at the ends thereof, such as a sixth rotating shaft of a six-axis robot, can be equipped with jigs, cutting tools, and detectors to perform various actions. Each wrist unit is rotated about an axis by a drive element. Each drive element includes a motor and gear mechanism.

The motion accuracy, load carrying capacity, and smoothness of the motion of the industrial robot wrist unit are affected by the meshing condition of the gear mechanism. If the backlash of the gear pair of the gear mechanism is large, during the transmission process, especially during frequent forward and reverse running, the gear pair is easy to produce impact, which will result in increased vibration and wear, reducing the accuracy and shortening of the gear transmission. The life of the gear mechanism. For the spur gear mechanism, because it is usually centered, when there is an error in the gear processing or installation process, a backlash will occur, so that the gear can not be rotated and meshed at the correct position during operation, which will reduce the transmission accuracy and the life of the gear mechanism. . The conventional technology mostly improves the manufacturing precision of the gear to achieve the purpose of reducing the backlash. However, this method not only directly increases the manufacturing cost of the gear, but also makes it difficult to adjust the backlash.

In view of the above, it is necessary to provide an adjustment device that eliminates the backlash of the spur gear and an industrial robot that uses the adjustment device and uses a gear mechanism for transmission.

A gear backlash adjusting device for adjusting a backlash of a spur gear device connected to a bevel gear device in an industrial robot, the spur gear device including a first gear and a second gear that mesh with each other. The bevel gear device includes two bevel gears that mesh with each other, wherein a bevel gear includes a gear shaft, and one of the second gear ends is provided with an axially receiving hole, and the gear shaft extends into the receiving hole and is coupled to the first The two gears are non-rotatingly coupled and the second gear is movable in the axial direction of the gear shaft. The first gear is fixed along its axial position, the displacement coefficients of the first gear and the second gear are linearly changed in the axial direction, and the larger end and the smaller end of the first gear shifting coefficient are respectively shifted from the second gear The smaller end of the bit coefficient and the larger end are correspondingly engaged, the gear backlash adjusting device includes an elastic member, the elastic member is sleeved on the gear shaft, and the second gear is sleeved on the elastic member by the receiving hole The elastic member is located between the second gear and the gear shaft, and the elastic member provides an elastic force that biases the second gear axially against the first gear.

Further, an industrial robot includes a first wrist unit rotatable about a first axis, a second wrist unit rotatable about a second axis, a first motor for driving the first wrist unit, and a first transmission chain, and And driving the second motor and the second transmission chain of the second wrist unit, the first axis is orthogonal to the second axis, and at least one of the first transmission chain and the second transmission chain comprises a spur gear device and a bevel gear device. The spur gear device includes a first gear and a second gear that mesh with each other. The bevel gear device includes two bevel gears that mesh with each other, wherein a bevel gear includes a gear shaft, and one of the second gear ends is provided with an axially receiving hole, and the gear shaft extends into the receiving hole and is coupled to the first a two-gear rotation connection, the second gear being axially movable along the gear shaft move. The industrial robot further includes a gear backlash adjusting device for adjusting a backlash of the spur gear device, the first gear is fixed along an axial position thereof, and the first gear and the second gear linearly change in a displacement coefficient in the axial direction, And the larger end and the smaller end of the first gear shifting coefficient respectively mesh with the smaller end and the larger end of the second gear shifting coefficient, the gear backlash adjusting device includes an elastic member, and the elastic member is sleeved on The second gear is sleeved on the elastic member by the accommodating hole, and the elastic member is located between the second gear and the gear shaft, and the elastic member provides axial displacement of the second gear To resist the elastic force of the first gear.

The displacement coefficient of the first gear and the second gear of the industrial robot in the axial direction changes linearly, and the second gear meshes with the first gear, and the elastic force is applied in the axial direction by the elastic member, so that the second gear can be axially Moving to abut against the first gear, thereby eliminating the backlash between the first gear and the second gear, so that the first gear and the second gear smoothly mesh, improving the stability and motion precision of the industrial robot transmission, and improving the spur gear The service life of the device.

100‧‧‧Industrial robot

11‧‧‧Four wrist unit

12‧‧‧ fifth wrist unit

13‧‧‧ sixth wrist unit

14‧‧‧First drive chain

15‧‧‧Second drive chain

112, 113‧‧‧ fork branch

1121, 1131‧‧‧ Gear mounting holes

1123, 1133‧‧‧5th shaft mounting hole

114‧‧‧Connecting Department

1142‧‧‧ Hollow

121‧‧‧ Sixth shaft mounting hole

141‧‧‧First drive shaft

142, 152‧‧‧ cylindrical gear unit

143‧‧‧First bevel gear unit

142a, 152a‧‧‧ first gear

142b, 152b‧‧‧ second gear

143a, 143b, 153a, 153b 154a, 154b‧‧‧ bevel gear

1412‧‧‧through holes

151‧‧‧Second drive shaft

153‧‧‧Second bevel gear unit

154‧‧‧ Third bevel gear unit

20‧‧‧Gear backlash adjustment device

1421, 1423‧‧‧ first end

1422, 1424‧‧‧ second end

21, 22‧‧‧ elastic parts

146‧‧‧ Gear shaft

1425‧‧‧ accommodating holes

1 is a perspective view of a wrist unit of an industrial robot according to an embodiment of the present invention.

2 is a cross-sectional view of the wrist unit of the industrial robot shown in FIG. 1 taken along the II-II direction.

Figure 3 is a partial enlarged view of a cross-sectional view of the wrist unit shown in Figure 2.

The gear backlash adjusting device of the present invention and the industrial robot using the adjusting device will be further described in detail below with reference to the accompanying drawings and specific embodiments, and a six-axis industrial robot will be described as an example.

1 and 2 show the office of the wrist unit of the industrial robot 100 according to the embodiment of the present invention. Department diagram. The industrial robot 100 is a six-axis industrial robot including a base, a bracket rotatably disposed on the base, a boom rotatably disposed at one end of the bracket, and a connecting wrist rotatably disposed on the boom. Not shown in the drawings. The industrial robot 100 further includes a fourth wrist unit 11 rotatably coupled to the connecting wrist, a fifth wrist unit 12 rotatable about the fifth axis A and supported by the fourth wrist unit 11, rotatable about the sixth axis B and The sixth wrist unit 13 supported by the five wrist unit 12 is configured to drive a first motor (not shown) of the fifth wrist unit 12 and the first transmission chain 14, and a second motor for driving the sixth wrist unit 13 ( The figure is not shown) and the second transmission chain 15. The fifth axis A is orthogonal to the sixth axis B. The front end of the sixth wrist unit 13 can be mounted with an actuator such as a jig, a cutter or a detecting instrument.

The fourth wrist unit 11 is a generally fork-shaped housing that includes a bifurcated branch 112, 113 and a connecting portion 114 that connects the bifurcated branches 112, 113. The connecting portion 114 is provided with a hollow portion 1142, and the fork branches 112, 113 are respectively provided with gear mounting holes 1121, 1131. The hollow portion 1142 and the gear mounting holes 1121, 1131 are substantially parallel to each other and both extend in a direction perpendicular to the fifth axis A. The binary branches 112, 113 also respectively open fifth axis mounting holes 1123, 1133 extending in the direction of the fifth axis A and coaxially disposed.

The fifth wrist unit 12 is substantially cylindrical and disposed between the two branches 112, 113, and the two ends thereof are rotatably disposed in the fifth shaft mounting holes 1123, 1133, respectively. The fifth wrist unit 12 has a sixth shaft mounting hole 121 extending in the sixth axis B direction along the axial direction. The sixth wrist unit 13 is rotatably disposed within the sixth shaft mounting hole 121 such that the sixth wrist unit 13 is rotatable about the sixth axis B and is rotatable about the fifth axis A following the fifth wrist unit 12.

The first drive chain 14 is for transmitting power of the first motor to the fifth wrist unit 12 such that the fifth wrist unit 12 is rotatable about the fifth axis A. The first transmission chain 14 includes a first The drive shaft 141, the spur gear device 142, and the first bevel gear device 143.

The first motor and the spur gear device 142 are respectively disposed at two ends of the first transmission shaft 141. The spur gear unit 142 includes a first gear 142a and a second gear 142b that mesh with each other. The specific structure of the spur gear unit 142 will be described in detail later. The first bevel gear device 143 includes two bevel gears 143a, 143b that mesh with each other, and the bevel gear 143a includes a gear shaft 146. Wherein, the first gear 142a is fixed to the first transmission shaft 141, the second gear 142b is non-rotatably connected to the gear shaft 146 and is movable along the axial direction thereof; the bevel gear 143b is fixedly disposed with respect to the fifth wrist unit 12 to drive the fifth The wrist unit 12 rotates about a fifth axis A. The first transmission shaft 141 opens a uniform through hole 1412 in the axial direction.

The second drive chain 15 is used to transmit the power of the second motor to the sixth wrist unit 13 to rotate the sixth wrist unit 13 about the sixth axis B. The second transmission chain 15 includes a second transmission shaft 151, a spur gear device 152, a second bevel gear 153, and a third bevel gear 154.

The second transmission shaft 151 is disposed through the through hole 1412 of the first transmission shaft, and the two ends of the second transmission shaft 151 extend outward from the through hole 1412. The second motor and the spur gear unit 152 are respectively mounted at the two ends of the second transmission shaft 151. The first motor and the second motor are respectively disposed on two axial sides of the fourth wrist unit 11. The spur gear unit 152 is similar to the spur gear unit 142 and includes a first gear 152a and a second gear 152b that mesh with each other. The first gear 142a is axially offset from the first gear 152a. The second bevel gear device 153 includes two intermeshing bevel gears 153a, 153b. The third bevel gear 154 includes two intermeshing bevel gears 154a, 154b. Wherein, the first gear 152a is relatively fixed to the second transmission shaft 151, the second gear 152b is interlocked with the bevel gear 153a and is movable along the axial direction thereof; the bevel gear 153b is fixedly disposed with respect to the bevel gear 154a; the bevel gear 154b is opposite to the sixth The wrist unit 13 is fixedly arranged to drive the sixth wrist unit 13 around The six axis B rotates.

FIG. 3 shows a gear backlash adjusting device 20 for adjusting an industrial robot. The manner in which the backlash of the spur gear units 142, 152 is adjusted by the gear backlash adjusting device 20 is similar. Hereinafter, the backlash adjusting device of the spur gear unit 142 will be described as an example. In the present embodiment, the first gear 142a and the second gear wheel 142b of the spur gear unit 142 are straight tooth involute gears.

The first gear 142a includes a first end 1421 and a second end 1422. From the first end 1421 to the second end 1422, the displacement coefficient of the first gear 142a linearly increases. In other words, the cylindrical surface of the top of the first gear 142a is tapered, and the tooth thickness thereof increases linearly with the displacement coefficient. The first end 1421 is a large diameter end and the second end 1422 is a small diameter end.

The second gear 142b includes a first end 1423 and a second end 1424. From the first end 1423 to the second end 1424, the displacement coefficient of the second gear 142b is linearly decreased. In other words, the cylindrical top surface of the second gear 142b is tapered, and the tooth thickness thereof linearly decreases with the displacement coefficient. The first end 1423 is a small diameter end and the second end 1424 is a large diameter end. The first end 1423 of the second gear 142b and the first end 1421 of the first gear 142a, the second end 1424 of the second gear 142b and the second end 1422 of the first gear 142a are respectively engaged.

Preferably, the taper of the first gear 142a and the second gear 142b is less than or equal to 5 degrees to maintain a better meshing condition.

In order to adjust the backlash between the first gear 142a and the second gear 142b, the elastic member 21 of the preset elastic force in the gear backlash adjusting device 20 can provide an elastic force along the axial direction of the second gear 142b, so that the first gear 142a and the first gear The two gears 142b abut each other to eliminate the backlash between the first gear 142a and the second gear 142b.

In this embodiment, the first gear 142a is fixed in the axial direction, and the second gear 142b It can be moved in the axial direction. The second gear 142b is non-rotatably coupled to the gear shaft 146 by a key and moves axially relative to the key. The second end 1424 of the second gear 142b defines an axial receiving hole 1425, and the gear shaft 146 extends into the receiving hole 1425. The elastic member 21 is sleeved on the gear shaft 146, and the second gear 142b is sleeved on the elastic member 21 via the receiving hole 1425. The elastic member 21 is located between the second gear 142b and the gear shaft 146, and the elastic member 21 is received in the elastic member 21. The inside of the hole 1425 is accommodated and elastically resists the second gear 142b. The elastic member 21 may be selected from a helical compression spring that is sleeved on a gear shaft 146 that is coupled to the second gear 142b.

When a backlash is generated between the first gear 142a and the second gear 142b, the elastic member 21 pushes against the second gear 142b to move the second gear 142b in the axial direction dd because the first gear 142a and the second gear 142b are tapered. After the second gear 142b moves a certain distance, it abuts against the second gear 142b, thereby eliminating the backlash. Similar to the second gear 142b, the second gear 152b receives an elastic member 22 at one end to abut the second gear 152b to eliminate the backlash. The above adjustment can be automatically performed, that is, when the spur gear device 142, 152 is operated, if the backlash changes due to changes in working conditions or environment, the elastic members 21, 22 can automatically adjust the positions of the second gear 142b, 152b in the axial direction, respectively. The backlash is eliminated, so that when the industrial robot 100 is in operation, the spur gear units 142, 152 can be kept substantially zero clearance, thereby improving the smoothness of the transmission, the motion accuracy, and the service life of the spur gear units 142, 152.

In summary, the present invention complies with the requirements of the invention patent, and submits a patent application according to law. However, the above is only a preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art will be included in the following claims.

142a‧‧‧First gear

142b‧‧‧second gear

20‧‧‧Gear backlash adjustment device

1421, 1423‧‧‧ first end

1422, 1424‧‧‧ second end

21‧‧‧Flexible parts

146‧‧‧ Gear shaft

1425‧‧‧ accommodating holes

Claims (8)

A gear backlash adjusting device for adjusting a backlash of a spur gear device connected to a bevel gear device in an industrial robot, the spur gear device comprising a first gear and a second gear meshing with each other, the improvement being: the bevel gear device Including two intermeshing bevel gears, wherein one of the bevel gears includes a gear shaft, one end of the second gear is provided with an axially receiving hole, the gear shaft extends into the receiving hole and stops with the second gear Connecting, the second gear is movable along an axial direction of the gear shaft, and the first gear is fixed along an axial position thereof, and the first gear and the second gear linearly change in a displacement coefficient in the axial direction, and the first The larger end and the smaller end of the gear shifting coefficient respectively mesh with the smaller end and the larger end of the second gear shifting coefficient, and the gear backlash adjusting device comprises an elastic member, and the elastic member is sleeved on the gear shaft The second gear is sleeved on the elastic member by the receiving hole, and the elastic member is located between the second gear and the gear shaft, and the elastic member provides axial offset of the second gear to abut against a gear Stretch. The gear backlash adjusting device according to claim 1, wherein the first gear and the second gear are straight tooth involute gears. The gear backlash adjusting device of claim 1, wherein the elastic member is a compression spring. An industrial robot comprising a first wrist unit rotatable about a first axis, a second wrist unit rotatable about a second axis, a first motor for driving the first wrist unit and a first drive chain, and for driving a second motor and a second drive chain of the second wrist unit, the first axis is orthogonal to the second axis, and at least one of the first drive chain and the second drive chain comprises a spur gear device and a bevel gear device, the spur gear The device includes a first gear and a second gear that mesh with each other, wherein the bevel gear device includes two bevel gears that mesh with each other, wherein one of the bevel gears includes a gear shaft, and one of the second gear ends is provided with an axial capacity Hole, this a gear shaft extends into the accommodating hole and is non-rotatably connected to the second gear, the second gear is movable along an axial direction of the gear shaft, and the industrial robot further includes a gear for adjusting a backlash of the spur gear device a backlash adjusting device, the first gear is fixed along its axial position, the first gear and the second gear linearly change in the axial direction, and the first gear shifting coefficient has a larger end and a smaller end respectively Cooperating with the smaller end of the second gear shifting coefficient and the larger end, the gear backlash adjusting device includes an elastic member, the elastic member is sleeved on the gear shaft, and the second gear is formed by the receiving hole sleeve Provided on the elastic member, the elastic member is located between the second gear and the gear shaft, and the elastic member provides an elastic force for axially offsetting the second gear to abut against the first gear. The industrial robot of claim 4, wherein the first gear and the second gear are straight tooth involute gears. The industrial robot of claim 4, wherein the elastic member is a compression spring. The industrial robot of any one of claims 4 to 6, wherein the first transmission chain comprises a spur gear device and a first transmission shaft, and the first gear of the spur gear is fixedly disposed at one end of the first transmission shaft The first motor is disposed at the other end of the first transmission shaft; the second transmission chain includes another spur gear device and a second transmission shaft, and the second transmission shaft and the first transmission shaft are mutually sleeved, the first motor The first gear of the spur gear device in the second transmission chain is fixedly disposed at one end of the second transmission shaft, and the second motor is disposed at the other end of the second transmission shaft. The industrial robot of claim 7, wherein the first gears respectively disposed on the first transmission shaft and the second transmission shaft are axially offset.