TWI468274B - Scara type robot - Google Patents

Description

Plane articulated robot

The present invention relates to a robot, and more particularly to a planar articulated industrial robot.

Planar articulated robots are one of the most widely used assembly robots and are designed for vertical mounting operations, such as plugging components on printed circuit boards. This type of robot has four joints: a three-level rotating joint and a vertical sliding joint, so that the gripping elements can be positioned in the horizontal direction and inserted or rotated in the vertical direction. The planar rotating joint can be relaxed to make small adjustments along the position of the hole when inserting the component, and is flexible, so it is called a Selective Compliance Assembly Robot Arm (SCARA).

A planar articulated robot comprising a base, a boom and an arm. A spindle and a stepping motor for driving the spindle are provided in the arm. The main shaft is provided with a spline fixed by a spline, and is driven by the belt between the stepping motor and the stepping motor. However, the use of the pulley drive is likely to cause the motor inertia ratio to be too large to be easily controlled, resulting in poor rigidity; and the belt is easily deformed when the spindle rotates at a high speed, resulting in low positioning accuracy.

In view of this, it is necessary to provide a planar articulated robot with better rigidity and higher precision.

A planar articulated robot that includes a base, a boom and an arm. The base has a first rotating shaft and a first motor that drives the first rotating shaft to rotate. One end of the boom can be used by the first shaft Rotatingly connected to the base. The arm includes a second rotating shaft and a second motor that drives the second rotating shaft, and is rotatably coupled to the other end of the boom by the second rotating shaft. The arm further includes a fixing base for fixing the second motor, a third motor fixed to the fixing seat, a third rotating shaft driven by the third motor, a screw rod movably connected to the fixing base, and a transmission device connecting the third rotating shaft and the screw rod a nut connected to the screw rod, a fourth motor fixedly connected to the nut, a fourth rotating shaft driven by the fourth motor, and a bearing assembly disposed on the fixing seat and extending through the fourth rotating shaft, the bearing assembly including a linear bearing, The sleeve and the rolling bearing, the fourth rotating shaft is disposed in the linear bearing, the sleeve is sleeved and fixed to the linear bearing, and the rolling bearing is disposed between the sleeve and the fixing seat. The friction between the fourth rotating shaft and the linear bearing is greater than the friction between the inner and outer rings of the rolling bearing, so that the linear bearing and the sleeve can form a whole with the fourth rotating shaft and rotate relative to the fixed seat under the limitation of the rolling bearing. .

Each of the rotating shafts of the above-mentioned planar articulated robot is directly driven and connected to each motor, and the conventional pulley, spline and other transmission mechanisms are omitted, and the rigidity is good and the precision is high.

100‧‧‧ Robot

10‧‧‧ Pedestal

20‧‧‧Big

30‧‧‧ Arm

11‧‧‧First shaft

13‧‧‧First motor

31‧‧‧second shaft

32‧‧‧second motor

33‧‧‧ Third shaft

34‧‧‧third motor

35‧‧‧Transmission

36‧‧‧Spindle

37‧‧‧ nuts

38‧‧‧fourth motor

39‧‧‧fourth shaft

40‧‧‧ bearing assembly

41‧‧‧Linear bearings

43‧‧‧ sleeve

45‧‧‧ rolling bearings

47‧‧‧ card ring

301‧‧‧ fixed seat

302‧‧‧Shell

351‧‧‧First pulley

353‧‧‧Second pulley

355‧‧‧Land

361‧‧‧ rail seat

363‧‧‧rails

371‧‧‧Connecting plate

373‧‧‧ Slider

364‧‧‧screw

365‧‧ ‧block

381‧‧‧Reducer

391‧‧‧connection hole

411‧‧‧ card slot

431‧‧‧ snap groove

FIG. 1 is a schematic diagram of a transmission principle of a planar articulated robot according to an embodiment of the present invention.

2 is a schematic perspective view of a planar articulated robot according to an embodiment of the present invention.

3 is a partial perspective view of the arm of the planar articulated robot shown in FIG. 2.

4 is a schematic cross-sectional view of the arm of the planar articulated robot shown in FIG. 2 taken along the IV-IV direction.

Figure 5 is a partial enlarged view of a portion V shown in Figure 4.

The planar articulated robot of the present invention will be further developed in conjunction with the drawings and embodiments. Step details.

Referring to FIG. 1 and FIG. 2 simultaneously, the robot 100 of the embodiment of the present invention is a planar articulated robot including a base 10, a boom 20 and an arm 30. The base 10 is used to mount the robot 100 to the ground or the table, and is internally provided with a first rotating shaft 11 and a first motor 13 that drives the rotation of the first rotating shaft 11. One end of the boom 20 is rotatably disposed on the base 10 by the first rotating shaft 11. A second rotating shaft 31 and a second motor 32 for driving the rotation of the second rotating shaft 31 are disposed in the arm 30. The arm 30 is rotatably disposed on the other end of the boom 20 by the second rotating shaft 31.

The arm 30 further includes a third rotating shaft 33, a third motor 34, a transmission 35, a lead screw 36, a nut 37, a fourth motor 38, a fourth rotating shaft 39, and a bearing assembly 40. The third motor 34 can drive the third shaft 33 to rotate. The transmission 35 is coupled to the third shaft 33 and the lead screw 36, respectively. The nut 37 is sleeved on the lead screw 36. The fourth motor 38 is fixed to the nut 37. The fourth rotating shaft 39 is driven and connected by the fourth motor 38 and is passed through the bearing assembly 40.

Referring to FIG. 3 and FIG. 4 simultaneously, the arm 30 further includes a fixing base 301 and a housing 302 mounted on the fixing base 301 and covering the other parts. The second motor 32, the third motor 34 and the bearing assembly 40 are fixedly mounted on the fixing base 301. The screw rod 36 is rotatably mounted on the fixing base 301 by a connecting seat (not shown). The overall center of gravity of 30 is lower and closer to the boom 20 to reduce inertia and increase rigidity. The transmission 35 includes a first pulley 351, a second pulley 353, and a belt 355. The first pulley 351 is sleeved and fixed to the third rotating shaft 33. The second pulley 353 is sleeved and fixed to the bottom end of the screw 36. The belt 355 is coupled to the first pulley 351 and the second pulley 353, respectively, and can transmit power from the first pulley 351 to the second pulley 353.

In order to ensure the accuracy of the nut 37 moving axially along the screw 36, the arm 30 further includes a rail seat 361, a rail 363, a connecting plate 371, and a slider 373. The rail seat 361 is fixed to the solid The seat 301 is located between the third motor 34 and the lead screw 36 to save internal space as much as possible. The guide rail 363 is substantially a strip parallel to the lead screw 36 and is fixed to the rail mount 361 by a plurality of screws 364. The connecting plate 371 is sleeved at one end and fixed to the nut 37, and is fixed to the slider 373. The fourth motor 38 is fixedly mounted to the other end of the connecting plate 371. The slider 373 is movably engaged with the guide rail 363, and when the nut 37 moves axially along the screw shaft 36, the slider 373 is slidable along the guide rail 363. In order to prevent the nut 37 from falling off from the top of the screw 36 when moving upward, a stopper 365 which can abut against the nut 37 is fixed to the top end of the screw 36. In the present embodiment, the screw 36 is a ball screw, and the nut 37 is a ball nut.

In order to reduce the rotational speed of the fourth motor 38 and increase the output torque, the third arm 30 further includes a speed reducer 381. The speed reducer 381 is fixed to the connecting plate 371 and disposed between the fourth motor 38 and the fourth rotating shaft 39. In the present embodiment, the fourth motor 38 is a low inertia servo motor, and the speed reducer 381 is a solid shaft harmonic reducer.

A connecting hole 391 is formed at the end of the fourth rotating shaft 39. Various types of end effectors, such as clamps, detecting devices, tools, and the like, may be coupled to the fourth rotating shaft 39 via the connecting holes 391.

Referring to FIG. 5, the bearing assembly 40 includes a linear bearing 41, a sleeve 43, two rolling bearings 45, and two snap rings 47. The fourth rotating shaft 39 is bored in the linear bearing 41. The axial frictional force between the fourth rotating shaft 39 and the linear bearing 41 is small, so that the fourth rotating shaft 39 can slide up and down in the axial direction inside the linear bearing 41. An annular card slot 411 is defined in each of the upper and lower ends of the linear bearing 41. The two snap rings 47 are respectively inserted into the two card slots 411. The sleeve 43 is sleeved on the linear bearing 41 and located between the two snap rings 47. Thereby, the sleeve 43 and the linear bearing 41 are fixed together. A stepped engagement groove 431 is defined in each of the upper and lower ends of the sleeve 43. The two rolling bearings 45 are respectively sleeved on both ends of the sleeve 43 , and the inner ring of the rolling bearing 45 is engaged and fixed to the engaging groove 431 . The outer ring of the rolling bearing 45 is fixed to the fixing base 301. The friction between the inner and outer rings of the rolling bearing 45 is smaller than between the fourth rotating shaft 39 and the linear bearing 41 Friction. In the present embodiment, the rolling bearing 45 is a deep groove ball bearing having a low cost.

Only the operation of the arm 30 will be described below, and the rest of the mechanism of the robot 100, such as the base 10 and the boom 20, be similar to the existing robot. When the fourth rotating shaft 39 is required to perform linear motion, the third motor 34 drives the third rotating shaft 33 to rotate, drives the first pulley 351 to rotate, and drives the second pulley 353 to rotate via the belt 355, thereby finally driving the screw 36 to rotate. The nut 37 disposed on the lead screw 36 drives the connecting plate 371 to move axially along the screw rod 36, thereby driving the fourth motor 38, the speed reducer 381 and the fourth rotating shaft 39 to linearly move together, and driving the slider 373 along the guide rail. 363 sliding. Since the axial friction between the fourth rotating shaft 39 and the linear bearing 41 is small, the fourth rotating shaft 39 can move in the axial direction within the linear bearing 41. When the fourth rotating shaft 39 is required to perform a rotational motion, the fourth motor 38 is decelerated by the speed reducer 381 to drive the fourth rotating shaft 39 to rotate. When the fourth rotating shaft 39 rotates, since the frictional force between the fourth rotating shaft 39 and the linear bearing 41 is greater than the friction between the inner and outer rings of the rolling bearing 45, the linear bearing 41 and the sleeve 43 will form a whole with the fourth rotating shaft 39. Rotating relative to the fixed seat 301 under the restriction of the rolling bearing 45.

Compared with the conventional robot, the fourth rotating shaft 39 of the present embodiment is directly driven and connected with the fourth motor 38, and the conventional pulley, spline and other transmission mechanisms are omitted, so that the precision is high, the rigidity is good, and the response speed is fast. Experiments have shown that the maximum load of the robot 100 of the present embodiment is 20 kg, and an eccentric amount of 100 mm or more is allowed.

It can be understood that the rolling bearing 45 can also be a deep groove ball bearing, for example, an angular contact ball bearing, a cylindrical roller bearing, etc.; the number of the rolling bearings 45 can also be one or more than two. If the linear bearing 41 of the bearing assembly 40 is directly connected to the rolling bearing 45, the sleeve 43 can also be omitted. If the frictional force between the fourth rotating shaft 39 and the linear bearing 41 is smaller than the frictional force of the rolling bearing 45, the fourth rotating shaft 39 rotates in the linear bearing 41.

If the rotational speed of the fourth motor 38 is low, the speed reducer 381 can also be omitted. If the top end of the lead screw 36 is fixed to the fixing base 301 of the arm 30, the guide rail 363, the rail seat 361 and the slider 373 can also be omitted.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

100‧‧‧ Robot

10‧‧‧ Pedestal

11‧‧‧First shaft

13‧‧‧First motor

20‧‧‧Big

30‧‧‧ Arm

31‧‧‧second shaft

32‧‧‧second motor

33‧‧‧ Third shaft

34‧‧‧third motor

35‧‧‧Transmission

36‧‧‧Spindle

37‧‧‧ nuts

38‧‧‧fourth motor

39‧‧‧fourth shaft

40‧‧‧ bearing assembly

Claims (8)

a planar articulated robot comprising: a base having a first rotating shaft and a first motor rotating by the first rotating shaft of the driving item; and a boom having one end rotatably coupled to the first rotating shaft The base is coupled; and the arm includes a second rotating shaft and a second motor for driving the second rotating shaft, the arm is rotatably connected to the other end of the large arm by the second rotating shaft; The arm further includes a fixing base for fixing the second motor, a third motor fixed to the fixing seat, a third rotating shaft driven by the third motor, a screw rod movably connected to the fixing base, and the connecting rod a third rotating shaft, a transmission device of the screw rod, a nut movably connected to the screw rod, a fourth motor fixedly connected to the nut, a fourth rotating shaft driven by the fourth motor, and a fourth rotating shaft mounted on the fixing base and provided for the first rotating shaft a four-rotor bearing assembly, the bearing assembly includes a linear bearing, a sleeve and a rolling bearing, the fourth rotating shaft is disposed in the linear bearing, the sleeve is sleeved and fixed to the linear bearing, and the rolling bearing is disposed on the sleeve Between the barrel and the holder, the Four of friction between the shaft and the linear bearing is greater than the frictional force between the inner and outer rings of the rolling bearing, thereby enabling the linear bearing and the sleeve and the fourth shaft can be formed integrally relative to the fixed seat to limit rotation of the rolling bearing. The planar articulated robot of claim 1, wherein the arm further comprises a rail and a slider, the rail is fixed relative to the fixing bracket and parallel to the screw rod, and the slider is fixedly connected with the nut, The slider is movably connected to the rail. The planar articulated robot of claim 2, wherein the arm further comprises a rail seat, the rail seat is fixed on the fixing seat and located between the third motor and the screw rod, the rail is fixed On the rail seat. A planar articulated robot as claimed in claim 2, wherein: the arm further comprises The connecting plate and the fourth motor are fixedly connected to the nut by the connecting plate. The plane joint type robot according to claim 1, wherein the arm further comprises a speed reducer, wherein the fourth shaft is connected to the fourth motor by the speed reducer, and the speed reducer is a solid shaft harmonic reducer. . The planar articulated robot of claim 1, wherein a sidewall of each of the two ends of the linear bearing is respectively provided with a card slot, and the bearing assembly further comprises a second snap ring, and the two snap rings are respectively inserted into the two card slots. Inside, and the sleeve is located between the two snap rings. The planar articulated robot of claim 1, wherein the rolling bearing is a deep groove ball bearing. The planar articulated robot of claim 1, wherein the fourth motor is a low inertia servo motor.