A lead screw assembly and robot

Abstract

The present application provides a kind of screw rod assembly and robot, screw rod assembly includes: screw rod, first transmission wheel, second transmission wheel, screw rod nut inner ring, spline nut inner ring and magnetic force device, first transmission wheel can drive screw rod nut inner ring rotation, second transmission wheel can drive spline nut inner ring rotation, magnetic force device can generate magnetic force so that first transmission wheel and second transmission wheel generate force in opposite directions, in turn make spline nut inner ring generate the movement or movement tendency to the direction of far away from screw rod nut inner ring, screw rod nut inner ring generates the movement or movement tendency to the direction of far away from spline nut inner ring.According to the present application, axial pre-tightening force can be applied to the spline nut inner and outer ring, reducing the radial runout of spline nut inner ring, while applying axial pre-tightening force to the screw rod nut inner and outer ring, reducing the radial runout of screw rod nut inner ring, thereby improving the SCARA robot J3, J4 joint repeatability positioning accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial robots, in particular to a screw rod assembly and a robot. BACKGROUND

[0002] The SCARA robot J3, J4 shaft is composed of a ball screw spline, the ball screw spline is composed of a screw rod, a spline nut and a screw nut, and has the following defects: (1) the spline nut and the screw nut are divided into an inner ring and an outer ring, the inner and outer rings are similar to the matching of a bearing, and have the same radial runout problem as the bearing, causing poor repeatability of the J3, J4 shaft; (2) the radial force brought by the load is entirely borne by the screw nut, which affects the service life of the screw rod to some extent.

[0003] Due to the radial runout of the inner and outer rings of the spline nut and the screw nut of the horizontal multi-joint robot in the prior art, the SCARA robot J3, J4 joint has low repeatability positioning accuracy, and therefore the present application designs a screw rod assembly and a robot. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to overcome the defects of the radial runout of the inner and outer rings of the spline nut and the screw nut of the horizontal multi-joint robot in the prior art, which leads to low repeatability positioning accuracy of the J3, J4 joint, so as to provide a screw rod assembly and a robot.

[0005] In order to solve the above problems, the present application provides a screw rod assembly, which comprises:

[0006] The screw rod, the first transmission wheel, the second transmission wheel, the screw nut inner ring, the spline nut inner ring and the magnetic force device, the first transmission wheel can drive the screw nut inner ring to rotate, the second transmission wheel can drive the spline nut inner ring to rotate, the magnetic force device can generate a magnetic force to make the first transmission wheel and the second transmission wheel generate forces in opposite directions, thereby making the spline nut inner ring generate movement or movement tendency away from the screw nut inner ring, and the screw nut inner ring generates movement or movement tendency away from the spline nut inner ring.

[0007] In some embodiments, the magnetic force device comprises a first magnetic structure and a second magnetic structure, the first magnetic structure is connected with the first transmission wheel as a whole, the second magnetic structure is connected with the second transmission wheel as a whole, and the first magnetic structure and the second magnetic structure generate a magnetic repulsion force.

[0008] In some embodiments, the first magnetic structure is an electromagnet or a permanent magnet, and the second magnetic structure is an electromagnet or a permanent magnet.

[0009] In some embodiments, the first magnetic structure is disposed on an end surface of a side of the first transmission wheel facing the second transmission wheel, and the second magnetic structure is disposed on an end surface of a side of the first transmission wheel facing the second transmission wheel; the first magnetic structure and the second magnetic structure are oppositely and spacedly disposed.

[0010] In some embodiments, the first magnetic structure and the second magnetic structure are both annular structures, and both allow the lead screw to pass therethrough.

[0011] In some embodiments, the lead screw nut assembly further comprises a lead screw nut outer ring, the lead screw nut outer ring is sleeved on an outer periphery of the lead screw nut inner ring, the lead screw nut inner ring is rotatable relative to the lead screw nut outer ring, and the lead screw nut outer ring further limits axial movement of the lead screw nut inner ring; the lead screw nut inner ring and the lead screw nut outer ring constitute a lead screw nut.

[0012] An inner peripheral wall of the lead screw nut inner ring is provided with an internal thread, an outer peripheral wall of the lead screw is provided with an external thread, the internal thread and the external thread are matched and connected, so that a matched screw pair is formed between the lead screw nut inner ring and the lead screw; when the lead screw nut inner ring is driven to rotate, the lead screw is driven to rotate and simultaneously axially move relative to the lead screw nut inner ring.

[0013] In some embodiments, the spline nut assembly further comprises a spline nut outer ring, the spline nut outer ring is sleeved on an outer periphery of the spline nut inner ring, the spline nut inner ring is rotatable relative to the spline nut outer ring, and the spline nut outer ring further limits axial movement of the spline nut inner ring; the spline nut inner ring and the spline nut outer ring constitute a spline nut.

[0014] An inner peripheral wall of the spline nut inner ring is provided with a spline groove, an outer peripheral wall of the lead screw is provided with a spline, the spline and the spline groove are matched and connected, so that a matched rotation pair is formed between the spline nut inner ring and the lead screw; when the spline nut inner ring is driven to rotate, the lead screw is driven to rotate integrally with the spline nut inner ring, and the lead screw is axially movable relative to the spline nut inner ring.

[0015] The application further provides a robot comprising the lead screw assembly.

[0016] In some embodiments, when the lead screw assembly further comprises a lead screw nut outer ring and a spline nut outer ring:

[0017] The robot further comprises a first mechanical arm and a second mechanical arm, one end of the first mechanical arm is formed as a first rotating shaft, i.e., a J1 shaft, the first mechanical arm can rotate around the J1 shaft, the other end of the first mechanical arm is rotationally connected with one end of the second mechanical arm, forming a second rotating shaft, i.e., a J2 shaft, the second mechanical arm can rotate around the J2 shaft, the other end of the second mechanical arm is provided with the lead screw, the first transmission wheel, the second transmission wheel, the inner ring of the lead screw nut and the spline nut inner ring; the outer ring of the lead screw nut is fixedly connected with the second mechanical arm, and the outer ring of the spline nut is fixedly connected with the second mechanical arm.

[0018] In some embodiments, the second mechanical arm is further provided with a third motor and a fourth motor, the third motor can drive the first transmission wheel to rotate, and the fourth motor can drive the second transmission wheel to rotate; the first transmission wheel is a lead screw nut belt wheel, and the second transmission wheel is a spline nut belt wheel, by simultaneously driving the first transmission wheel and the second transmission wheel to rotate, the axial movement and / or rotation of the lead screw can be driven.

[0019] The lead screw assembly and the robot provided by the application have the following beneficial effects:

[0020] The magnetic force device generates forces in opposite directions on the first transmission wheel and the second transmission wheel, and further generates movement or movement tendency of the spline nut inner ring away from the lead screw nut inner ring, and generates movement or movement tendency of the lead screw nut inner ring away from the spline nut inner ring, so that the axial pre-tightening force can be applied to the spline nut inner and outer rings, the radial runout of the spline nut inner ring is reduced, the axial pre-tightening force can be applied to the lead screw nut inner and outer rings, the radial runout of the lead screw nut inner ring is reduced, and the J3 and J4 joint repeatability positioning accuracy of the SCARA robot is improved. On the other hand, the magnetic force generated by the magnetic force device effectively disperses the axial force generated by the ball screw spline end load to the spline nut, reduces the stress of the lead screw nut, and improves the service life of the lead screw nut. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a front structure diagram of the multi-joint robot (SCARA robot) of the application;

[0022] Figure 2 is Figure 1 is a partial enlarged view of the lead screw assembly part in

[0023] The reference signs are represented as:

[0024] 1, base; 2, first motor; 3, first speed reducer; 4, first mechanical arm; 5, second speed reducer; 6, second motor; 7, second mechanical arm; 8, third motor; 9, fourth motor; 10, screw rod; 11, screw nut; 111, inner ring of screw nut; 112, outer ring of screw nut; 12, spline nut; 121, inner ring of spline nut; 122, outer ring of spline nut; 13, first transmission wheel; 14, second transmission wheel; 15, first magnetic structure; 16, second magnetic structure; 17, ball. DETAILED DESCRIPTION

[0025] In the description of the present application, it should be noted that the terms "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0026] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "contact", "communication" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0027] First part: working principle of SCARA robot

[0028] As shown in Figure 1 , the SCARA robot comprises a base 1, a first motor 2, a first speed reducer 3, a first mechanical arm 4, a second speed reducer 5, a second motor 6, a second mechanical arm 7, a third motor 8, a fourth motor 9, a screw rod 10, a screw nut 11, a spline nut 12;

[0029] As shown in Figure 1 , the first motor 2 is fixed on the base 1; the motor output shaft is connected with the first speed reducer 3; the first speed reducer 3, the input end is connected with the output shaft of the first motor 2, and the output end is connected with the first mechanical arm 4; the first mechanical arm 4, one end is connected with the output end of the first speed reducer 3. Under the action of the first speed reducer 3, the first motor 2 drives the first mechanical arm 4 and the parts mounted thereon to rotate around the J1 axis.

[0030] As shown in Figure 1As shown, the second motor 6 is installed on the second mechanical arm 7. The input end of the second speed reducer 5 is connected with the motor output shaft of the second motor 6, and the output end is connected with the first mechanical arm 4. Under the action of the second speed reducer 5, the second motor 6 drives the second mechanical arm 7 and the parts installed thereon to rotate around the J2 axis.

[0031] As shown in the figure, Figure 1 The third motor 8 is installed on the second mechanical arm 7, and the third motor 8 drives the screw nut 11, which is assembled with the screw rod 10, to control the screw rod 10 to move linearly along the J3 axis.

[0032] As shown in the figure, Figure 1 The fourth motor 9 is installed on the second mechanical arm 7, and the fourth motor 9 drives the spline nut 12 to rotate, which is assembled with the screw rod 10, and under the cooperation of the screw nut 11, the screw rod 10 can be controlled to rotate around the J4 axis.

[0033] Second part: working principle of SCARA robot J1 or J2 axis

[0034] Generally, the J3 axis and the J4 axis of the SCARA robot are driven by the third motor 8 and the fourth motor 9 respectively to drive the screw nut inner ring 111 and the spline nut inner ring 121, so that the screw rod 10 moves up and down and rotates;

[0035] As shown in the figure, Figures 1-2 The screw nut 11 is composed of a screw nut inner ring 111 and a screw nut outer ring 112, and there is only one rotary pair between the screw nut outer ring 112 and the screw nut inner ring 111. The screw nut outer ring 112 is fixed with the screw nut mounting plate, and the two are fixed on the second mechanical arm 7. The cooperation between the screw rod 10 and the screw nut inner ring 111 is a screw pair. The screw nut inner ring 111 is fixed with the screw nut pulley (the first transmission pulley 13), and the third motor 8 drives the screw nut pulley to realize the movement control of the screw nut inner ring 111.

[0036] As shown in the figure, Figures 1-2 The spline nut 12 is composed of a spline nut inner ring 121 and a spline nut outer ring 122, and there is only one rotary pair between the spline nut outer ring 122 and the spline nut inner ring 121. The spline nut outer ring 122 is fixed with the second mechanical arm 7. The screw rod 10 and the spline nut inner ring 121 are spline-fitted, and they can move axially but not rotate. The spline nut inner ring 121 is fixed with the spline nut pulley (the second transmission pulley 14), and the fourth motor 9 drives the spline nut pulley to realize the movement control of the spline nut inner ring 121.

[0037] J3 axis movement: the rotation movement of the screw rod 10 is limited (as the screw rod 10 and the spline nut inner ring 121 are in spline fit, the rotation of the screw rod 10 is limited, i.e. the rotation movement of the spline nut inner ring 121 and the spline nut belt wheel (the second transmission wheel 14) is limited). The spline nut inner ring 111 is rotated, and the spline nut inner ring 111 will rotate and move axially on the screw rod 10 (because: the screw rod 10 and the spline nut inner ring 111 are in screw fit), however, as the axial movement of the spline nut inner ring 111 is limited (because: the spline nut outer ring 112 is fixed with the second mechanical arm 7, and only a rotation pair exists between the spline nut inner ring 111 and the spline nut outer ring 112), the axial movement of the spline nut inner ring 111 on the screw rod 10 is converted into the axial movement of the screw rod 10 on the spline nut inner ring 111.

[0038] J4 axis movement: when the screw rod 10 rotates synchronously with the spline nut inner ring 111 (i.e. the spline nut inner ring 121 + the spline nut belt wheel (the second transmission wheel 14) drives the screw rod 10 to rotate synchronously with the spline nut inner ring + the spline nut belt wheel), the relative position between the screw rod 10 and the spline nut inner ring 111 will not change, and the screw rod 10 and the spline nut inner ring 111 only have rotation movement relative to the spline nut outer ring. Therefore, the screw rod 10 only has rotation movement relative to the second mechanical arm 7, i.e. J4 axis.

[0039] Reasonable control of the J3 axis and the J4 axis together can realize the rotation and up-down movement of the screw rod.

[0040] Third part: the present application - a SCARA robot ball screw spline shaft

[0041] As shown in Figures 1-2 , the present application provides a screw rod assembly, which comprises:

[0042] The screw rod 10, the first transmission wheel 13, the second transmission wheel 14, the spline nut inner ring 111, the spline nut inner ring 121 and the magnetic force device, the first transmission wheel 13 can drive the spline nut inner ring 111 to rotate, the second transmission wheel 14 can drive the spline nut inner ring 121 to rotate, the magnetic force device can generate magnetic force to make the first transmission wheel 13 and the second transmission wheel 14 generate force in opposite directions, thereby making the spline nut inner ring 121 generate movement or movement trend in the direction away from the spline nut inner ring 111, and the spline nut inner ring 111 generates movement or movement trend in the direction away from the spline nut inner ring 121.

[0043] The application can generate the axial pre-tightening force on the inner and outer circles of the spline nut, reduce the radial run-out of the inner circle of the spline nut, simultaneously generate the axial pre-tightening force on the inner and outer circles of the screw nut, reduce the radial run-out of the inner circle of the screw nut, thereby improving the J3, J4 joint repeatability positioning accuracy of the SCARA robot. On the other hand, the magnetic force generated by the magnetic force device effectively disperses the axial force generated by the ball screw spline end load to the spline nut, reduces the stress of the screw nut, and improves the service life of the screw nut.

[0044] In some embodiments, the magnetic force device comprises a first magnetic structure 15 and a second magnetic structure 16, the first magnetic structure 15 is connected with the first transmission wheel 13 as a whole, the second magnetic structure 16 is connected with the second transmission wheel 14 as a whole, and the first magnetic structure 15 and the second magnetic structure 16 generate magnetic repulsion. This is the preferred structure form of the magnetic force device of the application, that is, it comprises a first and a second magnetic structure, and generates magnetic repulsion between the two, thereby generating an axial pre-tightening force on the inner circle of the spline nut to reduce the radial run-out of the inner circle of the spline nut, generating an axial pre-tightening force on the inner circle of the screw nut to reduce the radial run-out of the inner circle of the screw nut, improving the J3, J4 joint repeatability positioning accuracy; and reducing the stress of the screw nut and improving its service life.

[0045] The application provides a SCARA robot ball screw assembly structure, which comprises a ball screw spline (screw rod + spline nut + screw nut), a spline nut pulley (i.e. a second transmission wheel), a screw nut pulley (a first transmission wheel), a first electromagnet (i.e. a first magnetic structure), and a second electromagnet (i.e. a second magnetic structure).

[0046] The outer circle of the spline nut and the outer circle of the screw nut are fixed;

[0047] The first electromagnet, the spline nut pulley and the inner circle of the spline nut are fixed and installed together and can rotate relative to the outer circle of the spline nut; the second electromagnet, the screw nut pulley and the inner circle of the screw nut are fixed and installed together and can rotate relative to the outer circle of the screw nut.

[0048] Under certain conditions, the first electromagnet and the second electromagnet interact to generate axial forces in opposite directions, so that the inner and outer circles of the spline nut and the inner and outer circles of the screw nut generate opposite forces, realize axial pre-tightening and weaken radial run-out.

[0049] The interaction force generated by the first electromagnet and the second electromagnet can transfer part of the axial force of the load on the screw nut to the spline nut, thereby reducing the stress of the balls between the inner and outer rings of the screw nut.

[0050] In some embodiments, the first magnetic structure 15 is an electromagnet or a permanent magnet, and the second magnetic structure 16 is an electromagnet or a permanent magnet. This is a further preferred structure of the first and second magnetic structures of the application, both of which can be permanent magnets or electromagnets, or one can be an electromagnet and the other can be a permanent magnet, all of which can generate the same magnetic repulsion force.

[0051] In some embodiments, the first magnetic structure 15 is arranged on the end face of the side of the first transmission wheel 13 facing the second transmission wheel 14, and the second magnetic structure 16 is arranged on the end face of the side of the first transmission wheel 13 facing the second transmission wheel 14. The first magnetic structure 15 and the second magnetic structure 16 are arranged opposite and spaced apart. This is a further preferred structure and position of the first and second magnetic structures of the application, which are arranged opposite and spaced apart, can increase the strength of the magnetic repulsion force between them, improve the axial pre-tightening force of the spline nut inner ring and the screw nut inner ring, further improve the repeatability positioning accuracy, and further reduce the stress of the screw nut.

[0052] In some embodiments, the first magnetic structure 15 and the second magnetic structure 16 are both annular structures, both of which can allow the screw rod 10 to pass through. The first and second magnetic structures of the application are further preferred to be annular structures that can allow the screw rod to pass through, forming a complete and integral structure.

[0053] As shown in Figure 1 When the end of the screw rod 10 is under load, the force transmission process is screw rod 10→screw nut inner ring 111→balls 17→screw nut outer ring. Because the screw rod 10 and the spline nut inner ring 121 are in spline engagement, there is an axial degree of freedom, so the force applied by the load is entirely borne by the screw nut. This reduces the service life of the screw nut to some extent. Because the spline nut inner ring 121, the spline nut outer ring 122, and the balls between them have a certain amount of play, there is a certain amount of radial runout, which reduces the repeatability positioning accuracy to some extent.

[0054] Therefore, the application proposes a new SCARA robot ball screw spline shaft, which is characterized by a ball spline screw (screw rod 10 + spline nut 12 + screw nut 11), a spline nut pulley (second transmission wheel 14), a screw nut pulley (first transmission wheel 13), a first electromagnet (first magnetic structure 15), and a second electromagnet (second magnetic structure 16).

[0055] The second magnetic structure 16 is fixed to the inner ring of the spline nut 121 and the second transmission wheel 14. In some cases, it can be an electromagnet, and in some cases, it can be a permanent magnet. It generates an axial force in the opposite direction between it and the first magnetic structure 15. (During operation, the first and second electromagnets are always energized to generate repulsive force.)

[0056] The first magnetic structure 15 is fixed together with the inner ring 111 of the screw nut and the first transmission wheel 13 . In some cases, it can be an electromagnet, and in some cases, it can be a permanent magnet. It generates an axial force in opposite directions with the second magnetic structure 16 .

[0057] The first magnetic structure 15 and the second magnetic structure 16 are electromagnets or permanent magnets depending on the situation. When the first magnetic structure 15 is an electromagnet, the second magnetic structure 16 can be an electromagnet or a permanent magnet. When the second magnetic structure 16 is an electromagnet, the first magnetic structure 15 can be an electromagnet or a permanent magnet. An axial, opposite force is generated between the first magnetic structure 15 and the second magnetic structure 16. This force can change according to the load conditions, so that the spline nut 12 and the screw nut 11 are evenly stressed.

[0058] The gravity generated by the load is partially transferred to the spline nut assembly through the first magnetic structure 15 and the second magnetic structure 16. On the one hand, the force on the screw nut 11 is reduced, and on the other hand, when the force is transmitted

[0059] When the spline nut inner ring 121 is passed, it is equivalent to applying an axial preload to the spline nut 12, which can reduce the clearance between the spline nut inner ring 121, the spline nut outer ring 122, and the ball 17 (refer to the deep groove ball bearing

[0060] The principle of applying axial preload to the bearings) reduces radial runout and increases the repeatability of the J3 and J4 axes to a certain extent.

[0061] By applying an axial preload, the radial clearance can be reduced, thereby reducing the radial wobble of the screw and improving the repeatability. The degree of concentration required to reach a stable position is the repeatability.

[0062] In some embodiments, the outer ring of the screw nut 112 is further included.

[0063] The screw nut inner ring 111 is provided on the outer circumference of the screw nut inner ring 111. The screw nut inner ring 111 can rotate relative to the screw nut outer ring 112. The screw nut outer ring 112 also limits the axial movement of the screw nut inner ring 111. The screw nut inner ring 111 and the screw nut outer ring 112 constitute the screw nut 11;

[0064] The inner peripheral wall of the inner ring 111 of the screw nut is provided with an internal thread, and the outer peripheral wall of the screw 10 is provided with an internal thread.

[0065] An external thread is provided on it, and the internal thread is matched with the external thread, so that a matching spiral pair is formed between the inner ring 111 of the screw nut and the screw 10. When the inner ring 111 of the screw nut is driven to rotate alone, it drives the screw 10 to move axially relative to the inner ring 111 of the screw nut and can also rotate.

[0066] The present invention effectively forms a screw nut through the structure of the screw nut inner ring and the screw nut outer ring,

[0067] The outer ring of the nut is used to fix the second robot arm to support the inner ring of the screw nut. The inner ring of the screw nut can rotate relative to the outer ring of the screw nut, that is, the inner ring of the screw nut is driven to rotate by the first transmission wheel. The inner ring of the screw nut and the screw are connected by a spiral pair, that is, a threaded connection, and because the outer ring of the screw nut is connected to the screw

[0068] The inner ring of the nut is axially limited, so that when the inner ring of the screw nut rotates, the screw 5 is driven by the spiral pair to rotate and move axially (the inner ring of the screw nut is axially fixed), realizing the axial movement and

[0069] The rotating ones are: an internal thread is set on the inner wall of the inner ring of the screw nut, and an external thread is set at the corresponding position on the screw, so that the internal and external threads are matched with each other, and the screw can be driven to rotate by the rotation of the inner ring of the screw nut and can also move up and down along the axis.

[0070] In some embodiments, a spline nut outer ring 122 is further included, wherein the spline nut outer ring 122 is sleeved on the outer periphery of the spline nut inner ring 121, and the spline nut inner ring 121 is relative to the spline nut.

[0071] The female outer ring 122 rotates, and the spline nut outer ring 122 also limits the axial movement of the spline nut inner ring 121. The spline nut inner ring 121 and the spline nut outer ring 122 form the spline nut 12;

[0072] A spline groove is provided on the inner circumferential wall of the spline nut inner ring 121, and a spline is provided on the outer circumferential wall of the screw rod 10. The spline is matched with the spline groove, so that a matching rotating pair is formed between the spline nut inner ring 121 and the screw rod 10. When the spline nut inner ring 121 is driven to rotate alone, it drives the screw rod 10 to rotate integrally with the spline nut inner ring 121, and the screw rod 10 can move axially relative to the spline nut inner ring 121.

[0073] The present application effectively forms a spline nut through the structure of the spline nut inner ring and the spline nut outer ring, the spline nut outer ring is used for being fixed with the second mechanical arm to support the spline nut inner ring, the spline nut inner ring can rotate relative to the spline nut outer ring, that is, the spline nut inner ring is driven to rotate by the second transmission wheel, the spline nut inner ring and the screw rod are connected in a rotating pair, that is, spline connection, and the spline nut outer ring axially limits the spline nut inner ring, so that when the spline nut inner ring rotates, the screw rod is only driven to rotate by the rotating pair (the spline nut inner ring is axially fixed), and effective driving of the rotation of the screw rod is realized; and the inner wall of the spline nut inner ring is provided with a spline groove, and the corresponding position of the screw rod is provided with a spline, so that the spline cooperates with the spline groove, and the screw rod can be driven to only rotate by the rotation of the spline nut inner ring, and the screw rod can move up and down along the axis relative to the spline nut inner ring.

[0074] The present application also provides a robot comprising the screw rod assembly.

[0075] In some embodiments, when the screw rod assembly further comprises a screw rod nut outer ring 112 and a spline nut outer ring 122:

[0076] The robot further comprises a first mechanical arm 4 and a second mechanical arm 7, one end of the first mechanical arm 4 is formed into a first rotating shaft, that is, a J1 shaft, the first mechanical arm 4 can rotate around the J1 shaft, the other end of the first mechanical arm 4 is rotationally connected with one end of the second mechanical arm 7 to form a second rotating shaft, that is, a J2 shaft, the second mechanical arm 7 can rotate around the J2 shaft, and the other end of the second mechanical arm 7 is provided with the screw rod 10, the first transmission wheel 13, the second transmission wheel 14, the screw rod nut inner ring 111 and the spline nut inner ring 121; the screw rod nut outer ring 112 is fixedly connected with the second mechanical arm 7, and the spline nut outer ring 122 is fixedly connected with the second mechanical arm 7.

[0077] This is a further preferred structure of the horizontal screw rod assembly of the present application, one end of the first mechanical arm is formed into a rotatable J1 shaft, the first mechanical arm rotates around the J1 shaft, the other end of the first mechanical arm is rotationally connected with one end of the second mechanical arm to form a J2 shaft, so that the second mechanical arm can rotate around the J2 shaft, and the J1 shaft and the J2 shaft are both rotating, which can realize the effect of rotating at multiple different positions, and improve the freedom and flexibility of the robot work; the present application further comprises the structure of the screw rod, the sleeve, the friction plate and the transmission wheel at the other end of the second mechanical arm, which can effectively control the screw rod to rotate, that is, to rotate around the J4 shaft and to move axially along the J3 shaft, further improving the freedom of the robot work, and the spline and the screw rod nut outer ring are both fixedly connected with the second mechanical arm, which can support the spline and the screw rod nut inner ring, thereby driving the screw rod to rotate around the J4 and / or move axially along the J3 shaft.

[0078] In some embodiments, the second mechanical arm 7 is further provided with a third motor 8 and a fourth motor 9, the third motor 8 can drive the first transmission wheel 13 to rotate, and the fourth motor 9 can drive the second transmission wheel 14 to rotate; the first transmission wheel 13 is a screw nut belt wheel, and the second transmission wheel 14 is a spline nut belt wheel, by driving the first transmission wheel 13 and the second transmission wheel 14 to rotate at the same time, the screw rod 10 is driven to move axially and / or rotate. This is a further preferred structure of the horizontal screw rod assembly of the present application, that is, the third motor and the fourth motor are arranged on the second mechanical arm, respectively used for driving the first and second transmission wheels to rotate, and then effectively driving the screw rod to move axially and rotate through the screw rod and the spline nut inner ring, achieving the purpose of precise control.

[0079] The application provides a SCARA robot, which can apply appropriate axial pre-tightening force to the spline nut and the inner and outer rings of the screw nut on the ball screw spline, reduces the radial runout, and improves the J3 and J4 joint repeatability positioning accuracy of the SCARA robot. On the other hand, the axial force generated by the load at the end of the ball screw spline is dispersed to the spline nut, the stress on the screw nut is reduced, and the service life of the screw nut is improved.

[0080] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application. The above only describes the preferred embodiments of the present application, and it should be pointed out that, for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be regarded as the protection scope of the present application.

Claims

1. A lead screw assembly, characterized by: Comprising: a lead screw (10), a first transmission wheel (13), a second transmission wheel (14), a lead screw nut inner ring (111), a spline nut inner ring (121) and a magnetic device, the first transmission wheel (13) can drive the lead screw nut inner ring (111) to rotate, the second transmission wheel (14) can drive the spline nut inner ring (121) to rotate, the magnetic device can generate a magnetic force to make the first transmission wheel (13) and the second transmission wheel (14) generate a force in opposite directions, thereby making the spline nut inner ring (121) generate a movement or movement trend away from the lead screw nut inner ring (111), and the lead screw nut inner ring (111) generates a movement or movement trend away from the spline nut inner ring (121); The magnetic device comprises a first magnetic structure (15) and a second magnetic structure (16), the first magnetic structure (15) is connected with the first transmission wheel (13) as a whole, the second magnetic structure (16) is connected with the second transmission wheel (14) as a whole, and the first magnetic structure (15) and the second magnetic structure (16) generate a magnetic repulsion force.

2. The lead screw assembly according to claim 1, wherein: The first magnetic structure (15) is an electromagnet or a permanent magnet, and the second magnetic structure (16) is an electromagnet or a permanent magnet.

3. The lead screw assembly according to claim 1, wherein: The first magnetic structure (15) is arranged on the end face of the side of the first transmission wheel (13) facing the second transmission wheel (14), the second magnetic structure (16) is arranged on the end face of the side of the first transmission wheel (13) facing the second transmission wheel (14), and the first magnetic structure (15) and the second magnetic structure (16) are oppositely and spacedly arranged.

4. The lead screw assembly according to any one of claims 1-3, wherein: The first magnetic structure (15) and the second magnetic structure (16) are both annular structures and can allow the lead screw (10) to pass through.

5. The lead screw assembly according to any one of claims 1-3, further comprising a lead screw nut outer ring (112), the lead screw nut outer ring (112) is sleeved on the outer periphery of the lead screw nut inner ring (111), the lead screw nut inner ring (111) can rotate relative to the lead screw nut outer ring (112), the lead screw nut outer ring (112) also limits the axial movement of the lead screw nut inner ring (111), and the lead screw nut inner ring (111) and the lead screw nut outer ring (112) constitute a lead screw nut (11). ​ The inner peripheral wall of the screw nut inner ring (111) is provided with an internal thread, the outer peripheral wall of the screw rod (10) is provided with an external thread, the internal thread matches the external thread, so that a matched screw pair is formed between the screw nut inner ring (111) and the screw rod (10), and when the screw nut inner ring (111) is driven to rotate, the screw rod (10) is driven to move axially relative to the screw nut inner ring (111) and also rotate.

6. The screw rod assembly according to claim 5, characterized in that: Further comprising a spline nut outer ring (122), the spline nut outer ring (122) is sleeved on the outer periphery of the spline nut inner ring (121), the spline nut inner ring (121) rotates relative to the spline nut outer ring (122), the spline nut outer ring (122) also limits the axial movement of the spline nut inner ring (121), and the spline nut inner ring (121) and the spline nut outer ring (122) constitute a spline nut (12). The inner peripheral wall of the spline nut inner ring (121) is provided with a spline groove, the outer peripheral wall of the screw rod (10) is provided with a spline, the spline matches the spline groove, so that a matched rotation pair is formed between the spline nut inner ring (121) and the screw rod (10), and when the spline nut inner ring (121) is driven to rotate, the screw rod (10) rotates integrally with the spline nut inner ring (121), and the screw rod (10) can move axially relative to the spline nut inner ring (121).

7. A robot, characterized by: The screw rod assembly according to any one of claims 1-6.

8. The robot according to claim 7, characterized in that: When the screw rod assembly further comprises a screw nut outer ring (112) and a spline nut outer ring (122): The robot further comprises a first mechanical arm (4) and a second mechanical arm (7), one end of the first mechanical arm (4) is formed into a first rotation shaft, that is, a J1 shaft, the first mechanical arm (4) can rotate around the J1 shaft, the other end of the first mechanical arm (4) is rotationally connected with one end of the second mechanical arm (7), forming a second rotation shaft, that is, a J2 shaft, the second mechanical arm (7) can rotate around the J2 shaft, the other end of the second mechanical arm (7) is provided with the screw rod (10), the first transmission wheel (13), the second transmission wheel (14), the screw nut inner ring (111) and the spline nut inner ring (121); the screw nut outer ring (112) is fixedly connected with the second mechanical arm (7), and the spline nut outer ring (122) is fixedly connected with the second mechanical arm (7).

9. The robot according to claim 8, characterized in that: The second mechanical arm (7) is further provided with a third motor (8) and a fourth motor (9), the third motor (8) can drive the first transmission wheel (13) to rotate, the fourth motor (9) can drive the second transmission wheel (14) to rotate; the first transmission wheel (13) is a screw nut belt wheel, the second transmission wheel (14) is a spline nut belt wheel, by simultaneously driving the first transmission wheel (13) and the second transmission wheel (14) to rotate, the screw rod (10) is driven to move axially and / or rotate.

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