Four-axis robot

Abstract

The utility model discloses a four-axis robot. A large arm and a small arm of the four-axis robot are each internally provided with a set of synchronous belt wheel mechanism, one synchronous wheel in the large arm is fixed and does not rotate, the other synchronous wheel connected with the synchronous wheel does not rotate, and in other words, the angle between the end effector and the clamp fixedly connected to the synchronous wheel and the ground is kept unchanged; and the angle of the grabbing surface is not changed. According to the four-axis robot disclosed by the utility model, through the under-actuated design, a grabbed object is always parallel to the ground.

Description

[0001] The utility model requires the invention name is four-axis robot priority, application number is 2024102694218, application date is March 11, 2024. TECHNICAL FIELD

[0002] The utility model relates to a kind of four-axis robots, belong to industrial stacker robot field. BACKGROUND

[0003] Stacker robot is placed in tray or specified space according to certain arrangement, can realize automatic stacking according to program, can stack multiple layers.Stacker robot can greatly reduce labor intensity, save personnel cost, and has been widely applied in automatic flow line, handling stacking, container handling, machine tool feeding and discharging and other automatic handling operations.

[0004] At present, in the stacker robot, the small arm motor is mostly installed at the rotating joint of the large arm mechanism and the small arm mechanism, which leads to the self-weight of the small arm mechanism, and also leads to the large rotary inertia of the large arm mechanism.Each action of the robot is controlled by a separate motor, which is high in cost and difficult to control.The working range of the large and small arms is small due to the limitation of some special mechanical mechanisms.

[0005] Chinese utility model patent application (publication number CN112454325 A) discloses a novel multi-joint stacker robot, which comprises a foundation, a waist assembly, a large arm assembly, a small arm assembly and a wrist assembly connected in sequence, each connected assembly can rotate relative to each other, the waist assembly and the large arm assembly are connected through a first rotating joint, driving the first rotating joint can drive the large arm assembly to rotate around the waist assembly; the large arm assembly and the small arm assembly are connected through a second rotating joint, driving the second rotating joint can drive the small arm assembly to rotate around the large arm assembly; the small arm assembly and the wrist assembly are connected through a third rotating joint, driving the third rotating joint can drive the wrist to rotate around the small arm assembly; the first, second and third rotating joints can be driven individually or synchronously.The main drawbacks of CN112454325A are:

[0006] 1. The motor reducers driving the large and small arms are inside the large arm. When the large arm swings, it drives the two motor reducers to swing, so that (1) when the large arm rotates, the two motor reducers increase the self-load of the large arm, resulting in high energy consumption of the motor driving the large arm; (2) the force arm driving the small arm is the diameter of the small arm (the driving point is at the hinge between the large and small arms), which is a force-consuming lever drive, and the motor of the small arm consumes high energy; (3) the transmission driving the large and small arms is a synchronous wheel and synchronous belt transmission flexible connection, which has the disadvantages of weak load capacity, low precision, frequent maintenance and high cost.

[0007] 2. In order to keep the wrist in a vertical state, the first pulley, the second pulley and the third pulley all need to rotate around the pulley axis, and the first pulley will rotate with the large arm, so the ratio of the number of teeth of the pulleys needs to satisfy the relationship: N3 / N2=-N1 / N2-1, the mutual connection transmission requirements are complex, the assembly and debugging are difficult and the universality is not strong.

[0008] The robot arm disclosed in the prior Chinese utility model patent (publication number CN219054388U) of the applicant mainly has the following characteristics: the large arm mechanism and the small arm mechanism form parallelogram structures (parallel four-bar mechanisms) respectively, that is, the connecting line of points AEFD is a rotating parallelogram, and the connecting line of points DGHJ is a rotating parallelogram. The advantage is that a complex synchronous wheel and synchronous belt structure does not need to be arranged to keep the fixture at a certain angle relative to the horizontal plane at all times. However, the disadvantage is that the rotation range of the parallel four-bar mechanism is limited, and in the case of two sets of parallel four-bar mechanisms, the grabbing range of the robot arm will be greatly limited; in addition, arranging two sets of parallel four-bar mechanisms will increase the weight of the entire robot arm, resulting in a large rotational inertia of the robot arm and a large control difficulty. Utility model content

[0009] The utility model aims at providing a four-axis robot, which can keep the grabbed object parallel to the ground through the design of underdrive.

[0010] In order to achieve the above-mentioned purpose, the technical scheme adopted by the utility model is:

[0011] A four-axis robot, comprising an upper assembly rotatably mounted on a base; the upper assembly comprises a support, a large arm, a small arm, a first connecting rod and a second connecting rod; one end of the large arm driven by a large arm motor reducer is hingedly connected to the support, the other end of the large arm is rotatably connected to the axis M with one end of the small arm, a small arm motor reducer mounted on the support drives the first connecting rod to rotate, the other end of the first connecting rod is rotatably connected to one end of the second connecting rod, the other end of the second connecting rod is hingedly connected to the small arm, the large arm, the first connecting rod, the second connecting rod and a section of the small arm constitute a four-bar mechanism, and the rotation of the small arm motor reducer drives the small arm to rotate through the movement of the first connecting rod and the second connecting rod; the structural characteristics are as follows:

[0012] A first synchronous pulley is fixedly installed on the support, the axis of the first synchronous pulley coincides with the rotation axis K of the large arm, and the first synchronous pulley does not rotate, and the other end of the large arm or one end of the small arm is provided with a second synchronous pulley through a first synchronous shaft; a first synchronous belt is wound around the first synchronous pulley and the second synchronous pulley, so that the second synchronous pulley does not rotate around its axis when the large arm rotates;

[0013] The first synchronous shaft is further provided with a third synchronous wheel, and the other end of the small arm is provided with a fourth synchronous wheel through a second synchronous shaft, the small arm is connected to the axis N through the second synchronous shaft, the axis of the fourth synchronous wheel coincides with the axis N, and the second synchronous belt is wound around the third synchronous wheel and the fourth synchronous wheel, so that the fourth synchronous wheel does not rotate around its axis when the small arm rotates.

[0014] The second synchronous wheel and the third synchronous wheel are coaxially arranged and directly or indirectly fixedly connected, and the axes of the second synchronous wheel and the third synchronous wheel coincide with the axis M.

[0015] Therefore, by arranging the first synchronous wheel, the second synchronous wheel and the first synchronous belt in the large arm, and arranging the third synchronous wheel, the fourth synchronous wheel and the second synchronous belt in the small arm, no matter how the large arm and the small arm rotate, the first synchronous wheel remains stationary, and the second synchronous wheel does not rotate around its axis, the third synchronous wheel fixedly connected with the second synchronous wheel also does not rotate around its axis, and the fourth synchronous wheel also does not rotate around its axis, so that the end effector, the clamp and the grasped object always remain parallel to the ground.

[0016] In addition, compared with the prior robot arm of the applicant which adopts two groups of parallel four-bar mechanisms, the parallel four-bar mechanism of the small arm is completely cancelled, the weight of the whole robot arm is reduced, and the problem of limited grasping range of the robot arm caused by the parallel four-bar mechanism is avoided.

[0017] In addition, the small arm motor speed reducer is installed on the support, the self weight of the small arm mechanism is reduced in the movement process, and the rotational inertia of the large arm mechanism is also reduced. In addition, the small arm motor speed reducer is installed on the support, the acting torque of the small arm mechanism on the large arm mechanism is reduced, the load of the large arm mechanism is reduced, the torque of the rotary motor speed reducer is also reduced, and the overturning torque of the support is reduced.

[0018] According to the embodiments of the utility model, the utility model can be further optimized, and the following is a technical scheme formed after optimization:

[0019] In one preferred embodiment, the large arm and the small arm are each provided with a synchronous belt tensioning mechanism, two rollers are installed in each synchronous belt tensioning mechanism, and the two rollers respectively abut against the corresponding synchronous belt.

[0020] In one preferred embodiment, the second synchronous shaft is connected with an end effector, the fourth synchronous wheel and the end effector are directly fixed or indirectly relatively fixed, so that the fourth synchronous wheel does not rotate around its axis when the large arm and the small arm rotate, and a clamp rotary motor speed reducer is fixedly installed on the end effector, and the output end of the clamp rotary motor speed reducer is in transmission connection with a clamp.

[0021] In one preferred embodiment, the third synchronizing wheel is fixedly mounted on the first synchronizing shaft and does not rotate, and the fourth synchronizing wheel is fixedly mounted on the second synchronizing shaft; the first synchronizing shaft and the second synchronizing shaft can rotate around their own axes.

[0022] In another preferred embodiment, the third synchronizing wheel is sleeved on the first synchronizing shaft, and the fourth synchronizing wheel is sleeved on the second synchronizing shaft.

[0023] In one preferred embodiment, the base further comprises a motor controller group and a cooling fan inside; the motor controller group is electrically connected with the rotating motor speed reducer, the large arm motor speed reducer, the small arm motor speed reducer, and the clamp rotating motor speed reducer.

[0024] In one preferred embodiment, the base bottom is provided with a moving wheel mechanism, which comprises a connecting plate and a universal wheel that can move up and down; one end of the connecting plate is fixedly connected with the base, and the other end of the connecting plate is threadedly connected with the universal wheel.

[0025] In one preferred embodiment, the large arm, the first connecting rod, the second connecting rod, and a section of the small arm constitute a quadrilateral structure.

[0026] In one preferred embodiment, the base is fixedly provided with a rotating motor speed reducer inside, and an output end of the rotating motor speed reducer is connected with the upper transmission.

[0027] As a specific fixed connection mode, the first synchronizing wheel is fixedly mounted on the support through a synchronizing wheel fixing seat.

[0028] Compared with the prior art, the utility model has the beneficial effects that:

[0029] 1. The utility model adopts two groups of synchronous wheels, synchronous belts, and belt transmission structures that are connected with each other, one of the synchronous wheels is fixed and does not rotate, and the other synchronous wheel connected with the belt also does not rotate, that is, the angle between the end effector fixedly connected with the synchronous wheel and the ground remains unchanged, that is, the angle of the grabbing surface is ensured to be unchanged, through the under-actuated design, the mechanism is compact, the motor for controlling the angle is saved, and the load and cost are lower.

[0030] 2. Compared with the scheme of the applicant in the prior art for solving the problem that the angle of the clamp and the angle of the ground remain unchanged through a parallel four-bar linkage mechanism, the double synchronous belt and synchronous wheel mechanism of the utility model avoids the constraint of the limit angle of the parallel four-bar linkage structure, can improve the grabbing range of the robot, and has the whole working range with the large arm driving point as the center and the length of the large arm and the small arm as the radius.

[0031] 3. The control system is installed in the base, effectively reducing the wiring length between the motor and the driver, reducing electromagnetic interference, and saving cable cost.

[0032] 4. The utility model discloses all transmission devices, driving devices, control devices are arranged in the robot, thereby the shell and the body are easy to protect, and the protection performance of the robot can be improved obviously.

[0033] 5. The utility model discloses a detachable moving wheel mechanism, which can move the robot without using large lifting equipment, thus increasing the applicability of the factory building and enabling rapid deployment.

[0034] 6. The small arm motor reducer is installed on the rotating shaft support, which reduces the weight of the small arm mechanism and the rotational inertia of the large arm mechanism during movement.

[0035] 7. The small arm motor reducer is installed on the support, which reduces the torque of the small arm mechanism on the large arm mechanism, reduces the load of the large arm mechanism, reduces the torque of the rotating motor reducer, and reduces the overturning torque of the support. Finally, this design is convenient for installation and wiring, has a small size, and has less motion space interference. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is an isometric view of the four-axis robot of the utility model;

[0037] Figure 2 is a front view of the four-axis robot of the utility model;

[0038] Figure 3 is Figure 2 the right side view of

[0039] Figure 4 is Figure 2 the left side view of

[0040] Figure 5 is Figure 3 the A-direction sectional view of

[0041] Figure 6 is Figure 3 the B-direction sectional view of

[0042] Figure 7 is Figure 2 the top view of

[0043] Figure 8 is Figure 4 the C-direction sectional view of

[0044] Figure 9 is Figure 7 the partial enlarged view of the II range in

[0045] Figure 10 yes Figure 8 A magnified view of a portion of area I;

[0046] Figure 11 yes Figure 2 H-direction sectional view;

[0047] Figure 12 yes Figure 10 Example 2;

[0048] Figure 13 yes Figure 11 Example 2;

[0049] Figure 14 This is a schematic diagram of the maximum working range of a four-axis robot according to this utility model.

[0050] in:

[0051] 1-Base; 2-Rotary motor reducer; 3-Support; 4-Boom motor reducer; 5-Arm motor reducer; 6-Boom; 7-Arm; 8-End effector; 9-Clamping rotary motor reducer; 10-Clamping; 11-First link; 12-Second link; 13-Synchronous pulley fixing seat; 14-First synchronous pulley; 15-First synchronous belt; 16-Synchronous belt tensioning mechanism; 17-Second synchronous pulley; 18-Third synchronous pulley; 19-Second synchronous belt; 20-Fourth synchronous pulley; 21-First synchronous shaft; 22-Second synchronous shaft; 23-Motor controller assembly; 24-Cooling fan; 25-Moving wheel mechanism; 26-Connecting plate; 27-Universal wheel. Detailed Implementation

[0052] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other. For ease of description, the terms "upper," "lower," "left," and "right" appearing below only indicate that they correspond to the upper, lower, left, and right directions in the accompanying drawings and do not limit the structure.

[0053] Example 1

[0054] like Figure 1 and 2 As shown, the four-axis robot in this embodiment includes a base 1, a rotary motor reducer 2, and a support 3. The fixed end of the rotary motor reducer 2 is fixedly installed on the base 1, and its output end is connected to the upper structure of the robot for transmission. Driving the rotary motor reducer 2 can realize the overall rotation of the upper structure of the robot around the axis J.

[0055] like Figure 2 , 3As shown in Figure 5, the superstructure of a four-axis robot includes a support 3, a large arm motor reducer 4, a small arm motor reducer 5, a large arm 6, a small arm 7, a first link 11, and a second link 12. The support 3 is hinged to one end of the large arm 6 at point D, which is on axis K. The fixed end of the large arm motor reducer 4 is fixedly connected to one side of the support 3, and the output end of the large arm motor reducer 4 is drively connected to one end of the large arm 6, driving the large arm motor reducer 4 to rotate, thereby driving the large arm 6 to rotate around axis K. The other end of the large arm 6 is rotatably connected to one end of the small arm 7 at point G, which is on axis M. The other side of the support 3 is fixedly connected to the fixed end of the small arm motor reducer 5, and the output end of the small arm motor reducer 5 is drively connected to one end of the first link 11. For ease of description, the rotation point is referred to as point D. It should be noted that the actual point of rotation may not be point D. That is, the drive arm motor reducer 5 rotates, thereby causing the first connecting rod 11 to rotate around the axis L. The axis L and the axis K may or may not be collinear. The other end of the first connecting rod 11 is rotatably connected to one end of the second connecting rod 12 at point E. The other end of the second connecting rod 12 is rotatably connected to the forearm 7 at point F. At this time, the upper arm 6, the first connecting rod 11, the second connecting rod 12, and a section of the forearm 7 form a quadrilateral structure. When the drive arm motor reducer 5 rotates, it causes the first connecting rod 11 and the second connecting rod 12 to move, thereby causing the forearm 7 to rotate around the axis M.

[0056] like Figure 2 , 3 As shown in Figures 6, 7, 8, 9, and 10, the upper structure of a four-axis robot further includes a synchronous pulley fixing seat 13, a first synchronous pulley 14, a first synchronous belt 15, a synchronous belt tensioning mechanism 16, a second synchronous pulley 17, a third synchronous pulley 18, a second synchronous belt 19, a fourth synchronous pulley 20, a first synchronous shaft 21, and a second synchronous shaft 22. The support 3 is fixedly connected to one end of the synchronous pulley fixing seat 13, and the other end of the synchronous pulley fixing seat 13 is fixedly connected to the first synchronous pulley 14. The axis of the first synchronous pulley 14 coincides with the axis K and remains fixed relative to the support 3.

[0057] The one end of the first synchronous shaft 21 is sleeved with the other end of the big arm 6, the axis of the first synchronous shaft 21 coincides with the axis M, the second synchronous wheel 17 is coaxially fixedly connected with the first synchronous shaft 21, the second synchronous wheel 17 is connected with the first synchronous wheel 14 through the first synchronous belt 15, at this time, no matter how the big arm 6 rotates, the second synchronous wheel 17 will not rotate around the axis M, because the synchronous wheel and the synchronous belt transmission need one of the synchronous wheels to rotate, if one synchronous wheel is fixed relative to the axis and does not rotate, then the other synchronous wheel connected through the belt will not rotate, so the second synchronous wheel 17 will not rotate around the axis M; the third synchronous wheel 18 is coaxially fixedly connected with the first synchronous shaft 21 through the key, the other end of the small arm 7 is sleeved with the second synchronous shaft 22, the axis of the second synchronous shaft 22 is N, the fourth synchronous wheel 20 is coaxially fixedly connected with the second synchronous shaft 22 through the key, the third synchronous wheel 18 and the fourth synchronous wheel 20 are connected with the second synchronous belt 19 through the belt, because the first synchronous shaft 21 will not rotate around the axis M, then the third synchronous wheel 18 fixedly connected with the first synchronous shaft 21 will not rotate around the axis M, and the fourth synchronous wheel 20 will not rotate around the axis N, so no matter how the small arm 7 rotates around the axis M, the fourth synchronous wheel 20 will not rotate around the axis N, then the second synchronous shaft 22 will not rotate around the axis N; the big arm 6 and the small arm 7 are further provided with the synchronous belt tensioning mechanism 16, two rollers are installed in the synchronous belt tensioning mechanism 16, the two rollers are pressed to the outer sides of the first synchronous belt 15 and the second synchronous belt 19 respectively, the tightness of the first synchronous belt 15 and the second synchronous belt 19 is adjusted by adjusting the distance between the two rollers, so that the tightness of the synchronous belt is adjusted.

[0058] As Figure 2 , 7 , 9, 11, the upper part of a four-axis robot further comprises an end effector 8, a clamp rotating motor reducer 9, and a clamp 10. The end effector 8 is fixedly connected with the second synchronous shaft 22 through a key, the end effector 8 is fixedly connected with the fixed end of the clamp rotating motor reducer 9, the output end of the clamp rotating motor reducer 9 is in transmission connection with the clamp 10, and driving the clamp rotating motor reducer 9 to rotate can make the clamp 10 and the object gripped thereby rotate around the axis P.

[0059] As described above, no matter how the big arm 6 and the small arm 7 rotate, the second synchronous shaft 22 will not rotate around the axis, then the end effector 8, the clamp rotating motor reducer 9, the clamp 10 and the object gripped thereby always keep the angle unchanged relative to the ground, if the clamp 10 keeps horizontal to the ground, then it can be ensured that the robot always keeps parallel to the ground when carrying the object.

[0060] As Figure 1 , 2As shown in FIG. 1, 2 and 3, the base 1 further comprises a motor controller group 23 and a cooling fan 24 inside. The motor controller group 23 is electrically connected with the rotary motor reducer 2, the large arm motor reducer 4, the small arm motor reducer 5 and the clamp rotary motor reducer 9. The cooling fan 24 is installed inside the base 1 for air exchange between the inside and outside of the base 1. The motor controller group 23 installed inside the base 1 can reduce the length of the wire between the motor and the driver, reduce electromagnetic interference, save the cost of cable and make the wire neat.

[0061] As shown in FIG. 1, 2 and 3, the base 1 further comprises a motor controller group 23 and a cooling fan 24 inside. The motor controller group 23 is electrically connected with the rotary motor reducer 2, the large arm motor reducer 4, the small arm motor reducer 5 and the clamp rotary motor reducer 9. The cooling fan 24 is installed inside the base 1 for air exchange between the inside and outside of the base 1. The motor controller group 23 installed inside the base 1 can reduce the length of the wire between the motor and the driver, reduce electromagnetic interference, save the cost of cable and make the wire neat. Figure 1 、 2 As shown in FIG. 1, 2 and 3, the base 1 further comprises a moving wheel mechanism 25 at the lower part. The moving wheel mechanism 25 is composed of a connecting plate 26 and universal wheels 27. One end of the connecting plate 26 is bolted to the bottom of the base 1, and the other end is threadedly connected with the universal wheels 27. When the robot needs to be moved as a whole, the universal wheels 27 are rotated downward respectively to lift the robot to a certain height, so that the robot can be moved without a gantry crane. When the position is determined, the universal wheels 27 are rotated upward respectively to lower the base 1 of the robot to the ground, so that the robot can be deployed conveniently and quickly.

[0062] As shown in FIG. 1, 2 and 3, the base 1 further comprises a motor controller group 23 and a cooling fan 24 inside. The motor controller group 23 is electrically connected with the rotary motor reducer 2, the large arm motor reducer 4, the small arm motor reducer 5 and the clamp rotary motor reducer 9. The cooling fan 24 is installed inside the base 1 for air exchange between the inside and outside of the base 1. The motor controller group 23 installed inside the base 1 can reduce the length of the wire between the motor and the driver, reduce electromagnetic interference, save the cost of cable and make the wire neat. Figure 10 、 Figure 11 As shown in FIG. 1, 2 and 3, the base 1 further comprises a motor controller group 23 and a cooling fan 24 inside. The motor controller group 23 is electrically connected with the rotary motor reducer 2, the large arm motor reducer 4, the small arm motor reducer 5 and the clamp rotary motor reducer 9. The cooling fan 24 is installed inside the base 1 for air exchange between the inside and outside of the base 1. The motor controller group 23 installed inside the base 1 can reduce the length of the wire between the motor and the driver, reduce electromagnetic interference, save the cost of cable and make the wire neat.

[0063] ① The second synchronous wheel 17 is sleeved with the first synchronous shaft 21, and the third synchronous wheel 18 is fixedly connected with the second synchronous wheel 17.

[0064] ② The third synchronous wheel 18 is sleeved with the first synchronous shaft 21, and the second synchronous wheel 17 is fixedly connected with the third synchronous wheel 18.

[0065] ③ The second synchronous wheel 17 is fixedly connected with the first synchronous shaft 21, and the third synchronous wheel 18 is fixedly connected with the first synchronous shaft 21 or the third synchronous wheel 18 is fixedly connected with the second synchronous wheel 17.

[0066] As shown in FIG. 1, 2 and 3, the base 1 further comprises a motor controller group 23 and a cooling fan 24 inside. The motor controller group 23 is electrically connected with the rotary motor reducer 2, the large arm motor reducer 4, the small arm motor reducer 5 and the clamp rotary motor reducer 9. The cooling fan 24 is installed inside the base 1 for air exchange between the inside and outside of the base 1. The motor controller group 23 installed inside the base 1 can reduce the length of the wire between the motor and the driver, reduce electromagnetic interference, save the cost of cable and make the wire neat. Figure 11 As shown in FIG. 1, 2 and 3, the base 1 further comprises a motor controller group 23 and a cooling fan 24 inside. The motor controller group 23 is electrically connected with the rotary motor reducer 2, the large arm motor reducer 4, the small arm motor reducer 5 and the clamp rotary motor reducer 9. The cooling fan 24 is installed inside the base 1 for air exchange between the inside and outside of the base 1. The motor controller group 23 installed inside the base 1 can reduce the length of the wire between the motor and the driver, reduce electromagnetic interference, save the cost of cable and make the wire neat.

[0067] ① The fourth synchronous wheel 20 is sleeved with the second synchronous shaft 22, and the end effector 8 is fixedly connected with the fourth synchronous wheel 20.

[0068] ② The end effector 8 is sleeved with the second synchronous shaft 22, and the fourth synchronous wheel 20 is fixedly connected with the end effector 8.

[0069] ③ The fourth synchronous pulley 20 is fixedly connected to the second synchronous shaft 22, and the end effector 8 is fixedly connected to the fourth synchronous pulley 20 or the end effector 8 is fixedly connected to the second synchronous shaft 22.

[0070] Based on the above, the inventor concludes that: the second synchronous pulley 17 and the third synchronous pulley 18 are coaxial and directly or indirectly fixedly connected, and the axes of the second synchronous pulley 17 and the third synchronous pulley 18 coincide with the axis M.

[0071] Example 2

[0072] like Figure 12 As shown, unlike Embodiment 1, the first synchronous shaft 21 is fixedly connected to the hinge joint of the upper arm or forearm, and the second synchronous wheel 17 is fitted onto the first synchronous shaft 21. Therefore, the second synchronous wheel 17 and the first synchronous shaft 21 are not fixedly connected and can rotate relative to each other. The third synchronous wheel 18 is fixedly connected to the second synchronous wheel 17 and fitted onto the first synchronous shaft 21. It should be noted that the second synchronous wheel 17 and the third synchronous wheel 18 are directly or indirectly fixedly connected relative to each other and coaxially connected. This axis must coincide with the axis M of the hinge joint between the upper and lower arms.

[0073] Similarly, such as Figure 13 As shown, the second synchronous shaft 22 is fixedly connected to the hinge of the forearm 7, and the fourth synchronous wheel 20 is fitted to the second synchronous shaft 22. Therefore, the fourth synchronous wheel 20 and the second synchronous shaft 22 are not fixedly connected and can rotate relative to each other. The end effector 8 is fixedly connected to the fourth synchronous wheel 20.

[0074] like Figure 12 , Figure 13 As shown, in some embodiments, the first synchronous shaft 21 is fixedly connected to the upper arm 6 or the lower arm 7, specifically in the following two cases:

[0075] In the first scenario, the second synchronous pulley 17 is fitted with the first synchronous shaft 21, and the third synchronous pulley 18 is fixedly connected to the second synchronous pulley 17.

[0076] In the second scenario, the third synchronous pulley 18 is fitted with the first synchronous shaft 21, and the second synchronous pulley 17 is fixedly connected to the third synchronous pulley 18.

[0077] like Figure 13 As shown, in some other embodiments, the second synchronous shaft 22 is fixedly connected to the forearm 7, specifically in the following two cases:

[0078] In the first case, the fourth synchronous pulley 20 is assembled with the second synchronous shaft 22, and the end effector 8 is fixedly connected to the fourth synchronous pulley 20.

[0079] In the second scenario, the end effector 8 is assembled with the second synchronous shaft 22, and the fourth synchronous pulley 20 is fixedly connected to the end effector 8.

[0080] In summary, the second synchronizing wheel 17 is coaxial with the third synchronizing wheel 18 and is directly or indirectly fixedly connected, and the axis of the second synchronizing wheel 17 and the third synchronizing wheel 18 coincides with the axis M. The fourth synchronizing wheel 20 is directly or indirectly fixedly connected with the end effector 8, and the axis of the fourth synchronizing wheel 20 is on the axis N. Except that the first synchronizing wheel 14 is fixed and does not rotate, the other synchronizing wheels rotate around the axis when the large arm and the small arm 7 rotate, that is, in the plane, the first synchronizing wheel 14 is a fixed star wheel, and the synchronizing wheels connected with the first synchronizing wheel 14 through the synchronizing belt are planet wheels.

[0081] Embodiment 3

[0082] Different from the embodiment 1, since the fourth synchronizing wheel 20 does not rotate around the axis N, the end effector 8 is fixedly connected with the fourth synchronizing wheel 20, and the angle invariability can also be met.

[0083] The above-mentioned embodiments should be understood as merely illustrating the present application, and should not be used to limit the scope of the present application. After reading the present application, those skilled in the art can make various equivalent modifications to the embodiments, and all the modifications fall within the scope of the appended claims of the present application.

Claims

1. A four-axis robot, comprising a rotatable upper assembly mounted on a base (1); the upper assembly comprising a support (3), a large arm (6), a small arm (7), a first connecting rod (11), a second connecting rod (12); one end of the large arm (6) driven by a large arm motor reducer (4) is hinged to the support (3), the other end of the large arm (6) is rotatably connected to the small arm (7) at an axis M, a small arm motor reducer (5) mounted on the support (3) drives the first connecting rod (11) to rotate, the other end of the first connecting rod (11) is rotatably connected to one end of the second connecting rod (12), the other end of the second connecting rod (12) is hinged to the small arm (7), the large arm (6), the first connecting rod (11), the second connecting rod (12), and a section of the small arm (7) constitute a four-bar linkage mechanism, and rotation of the small arm motor reducer (5) drives the small arm (7) to rotate through the movement of the first connecting rod (11) and the second connecting rod (12); characterized in that: a first synchronous wheel (14) is fixedly mounted on the support (3), the axis of the first synchronous wheel (14) coincides with the rotation axis K of the large arm (6), and the first synchronous wheel (14) does not rotate by itself, the other end of the large arm (6) or one end of the small arm (7) is provided with a second synchronous wheel (17) through a first synchronous shaft (21); a first synchronous belt (15) is wound around the first synchronous wheel (14) and the second synchronous wheel (17), so that the second synchronous wheel (17) does not rotate by itself when the large arm (6) rotates; a third synchronous wheel (18) is further mounted on the first synchronous shaft (21), and a fourth synchronous wheel (20) is mounted on the other end of the small arm (7) through a second synchronous shaft (22), the small arm (7) and the second synchronous shaft (22) are connected at an axis N, the axis of the fourth synchronous wheel (20) coincides with the axis N, a second synchronous belt (19) is wound around the third synchronous wheel (18) and the fourth synchronous wheel (20), so that the fourth synchronous wheel (20) does not rotate by itself when the small arm (7) rotates; the second synchronous wheel (17) and the third synchronous wheel (18) are coaxially arranged and directly or indirectly fixedly connected, the axes of the second synchronous wheel (17) and the third synchronous wheel (18) both coincide with the axis M. an end effector (8) is connected to the second synchronous shaft (22), the fourth synchronous wheel (20) and the end effector (8) are directly fixed or indirectly relatively fixed, so that the fourth synchronous wheel (20) does not rotate by itself when the large arm (6) and the small arm (7) rotate; a clamp rotary motor reducer (9) is fixedly mounted on the end effector (8), and an output end of the clamp rotary motor reducer (9) is drivingly connected to a clamp (10).

2. The four-bar robot of claim 1, wherein, the third synchronous wheel (18) is fixedly mounted on the first synchronous shaft (21), and the third synchronous wheel (18) does not rotate by itself, the fourth synchronous wheel (20) is fixedly mounted on the second synchronous shaft (22); the first synchronous shaft (21) and the second synchronous shaft (22) can rotate by themselves around their respective axes.

3. The four-bar robot of claim 1, wherein, ​ 4. The four-bar robot of claim 1, wherein, The third synchronous wheel (18) is sleeved on the first synchronous shaft (21), and the fourth synchronous wheel (20) is sleeved on the second synchronous shaft (22).

5. The four-bar robot of claim 1, wherein, The base (1) further comprises a motor controller group (23) and a heat dissipation fan (24) inside; the motor controller group (23) is electrically connected with the rotary motor speed reducer (2), the large arm motor speed reducer (4), the small arm motor speed reducer (5) and the clamp rotary motor speed reducer (9).

6. The four-bar robot of claim 1, wherein, The base (1) is provided with a moving wheel mechanism (25) at the bottom, the moving wheel mechanism (25) comprises a connecting plate (26) and a universal wheel (27) which can move up and down; one end of the connecting plate (26) is fixedly connected with the base (1), and the other end of the connecting plate (26) is threadedly connected with the universal wheel (27).

7. The four-bar robot of claim 1, wherein, The rotary motor speed reducer (2) is fixedly installed in the base (1), and an output end of the rotary motor speed reducer (2) is connected with the upper transmission.

8. The four-bar robot of claim 1, wherein, The large arm (6) and the small arm (7) are both provided with a synchronous belt tensioning mechanism (16), and two roller wheels are installed in each synchronous belt tensioning mechanism (16), and the two roller wheels respectively abut against corresponding synchronous belts.

9. The four-bar robot of claim 1, wherein, The first synchronous wheel (14) is fixedly installed on the support (3) through a synchronous wheel fixing seat (13).

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