CN218953949U - Screw rod assembly and robot - Google Patents
Screw rod assembly and robot Download PDFInfo
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- CN218953949U CN218953949U CN202223606662.2U CN202223606662U CN218953949U CN 218953949 U CN218953949 U CN 218953949U CN 202223606662 U CN202223606662 U CN 202223606662U CN 218953949 U CN218953949 U CN 218953949U
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Abstract
The utility model provides a screw rod assembly and a robot, wherein the screw rod assembly comprises: the device comprises a screw rod, a first driving wheel, a second driving wheel, a screw rod nut inner ring, a spline nut inner ring and a magnetic device, wherein the first driving wheel can drive the screw rod nut inner ring to rotate, the second driving wheel can drive the spline nut inner ring to rotate, the magnetic device can generate magnetic force to enable the first driving wheel and the second driving wheel to generate force in opposite directions, further the spline nut inner ring generates movement or movement trend in the direction away from the screw rod nut inner ring, and the screw rod nut inner ring generates movement or movement trend in the direction away from the spline nut inner ring. According to the utility model, the axial pretightening force can be applied to the inner ring and the outer ring of the spline nut, the radial runout of the inner ring of the spline nut is reduced, and the axial pretightening force is applied to the inner ring and the outer ring of the screw nut, so that the radial runout of the inner ring of the screw nut is reduced, and the repeatability positioning precision of joints J3 and J4 of the SCARA robot is improved.
Description
Technical Field
The utility model relates to the technical field of industrial robots, in particular to a screw rod assembly and a robot.
Background
The shafts J3 and J4 of the SCARA robot are formed by ball screw splines, and the ball screw splines comprise screw rods, spline nuts and screw rod nuts, and have the following defects: (1) The spline nut and the screw nut are divided into an inner ring and an outer ring, the inner ring and the outer ring are matched similarly to a bearing, the spline nut and the screw nut have the same radial runout problem of the bearing, and the repeatability of J3 and J4 shafts is poor; (2) The radial force caused by the load is borne by the screw nut, and the service life of the screw is affected to a certain extent.
Because radial runout exists on the inner ring and the outer ring of the spline nut and the screw nut of the horizontal multi-joint robot in the prior art, the technical problems of low repeatability positioning precision of joints J3 and J4 of the SCARA robot are caused, and the like, the screw rod assembly and the robot are researched and designed.
Disclosure of Invention
Therefore, the technical problem to be solved by the utility model is to overcome the defect that the repeatability positioning precision of J3 and J4 joints is low due to radial runout of the spline nut and the inner ring and the outer ring of the screw nut of the horizontal multi-joint robot in the prior art, so as to provide the screw rod assembly and the robot.
In order to solve the above problems, the present utility model provides a screw assembly comprising:
the novel screw nut comprises a screw rod, a first driving wheel, a second driving wheel, a screw rod nut inner ring, a spline nut inner ring and a magnetic device, wherein the first driving wheel can drive the screw rod nut inner ring to rotate, the second driving wheel can drive the spline nut inner ring to rotate, the magnetic device can generate magnetic force to enable the first driving wheel and the second driving wheel to generate force in opposite directions, further the spline nut inner ring generates movement or movement trend in the direction far away from the screw rod nut inner ring, and the screw rod nut inner ring generates movement or movement trend in the direction far away from the spline nut inner ring.
In some embodiments, the magnetic device comprises a first magnetic structure and a second magnetic structure, the first magnetic structure is connected with the first driving wheel into a whole, the second magnetic structure is connected with the second driving wheel into a whole, and magnetic repulsion force is generated between the first magnetic structure and the second magnetic structure.
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.
In some embodiments, the first magnetic structure is disposed on an end face of the first drive wheel on a side facing the second drive wheel, and the second magnetic structure is disposed on an end face of the second drive wheel on a side facing the first drive wheel; the first magnetic structure is opposite to the second magnetic structure and is arranged at intervals.
In some embodiments, the first magnetic structure and the second magnetic structure are both annular structures, each allowing the screw to pass therethrough.
In some embodiments, the screw-nut assembly further comprises a screw-nut outer ring, wherein the screw-nut outer ring is sleeved on the periphery of the screw-nut inner ring, the screw-nut inner ring can rotate relative to the screw-nut outer ring, the screw-nut outer ring also limits the axial movement of the screw-nut inner ring, and the screw-nut inner ring and the screw-nut outer ring form a screw-nut;
the screw rod is characterized in that an inner thread is arranged on the inner peripheral wall of the screw rod nut inner ring, an outer thread is arranged on the outer peripheral wall of the screw rod, and the inner thread is matched and connected with the outer thread, so that a matched screw pair is formed between the screw rod nut inner ring and the screw rod, and the screw rod nut inner ring can drive the screw rod to move axially relative to the screw rod nut inner ring and simultaneously rotate when being driven to rotate independently.
In some embodiments, the spline nut further comprises a spline nut outer ring, the spline nut outer ring is sleeved on the periphery of the spline nut inner ring, the spline nut inner ring rotates relative to the spline nut outer ring, the spline nut outer ring further limits axial movement of the spline nut inner ring, and the spline nut inner ring and the spline nut outer ring form a spline nut;
the spline nut is characterized in that a spline groove is formed in the inner peripheral wall of the spline nut inner ring, a spline is arranged on the outer peripheral wall of the screw rod, the spline is connected with the spline groove in a matched mode, a matched rotating pair is formed between the spline nut inner ring and the screw rod, the spline nut inner ring is driven to integrally rotate along with the screw rod when being driven to rotate independently, and the screw rod can axially move relative to the spline nut inner ring.
The utility model also provides a robot which comprises the screw rod assembly.
In some embodiments, when the lead screw assembly further comprises a lead screw nut outer race and a spline nut outer race:
the robot further comprises a first mechanical arm and a second mechanical arm, wherein one end of the first mechanical arm is formed into a first rotating shaft, namely 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 to form a second rotating shaft, namely a J2 shaft, the second mechanical arm can rotate around the J2 shaft, and the other end of the second mechanical arm is provided with the screw rod, the first driving wheel, the second driving wheel, the screw rod nut inner ring and the spline nut inner ring; the screw nut outer ring is fixedly connected with the second mechanical arm, and the spline nut outer ring is fixedly connected with the second mechanical arm.
In some embodiments, a third motor and a fourth motor are further arranged on the second mechanical arm, the third motor can drive the first driving wheel to rotate, and the fourth motor can drive the second driving wheel to rotate; the first driving wheel is a screw nut belt wheel, the second driving wheel is a spline nut belt wheel, and the screw is driven to axially move and/or rotate by simultaneously driving the first driving wheel and the second driving wheel to rotate.
The screw rod assembly and the robot provided by the utility model have the following beneficial effects:
according to the utility model, by arranging the magnetic device, the first driving wheel and the second driving wheel are subjected to opposite force, so that the inner ring of the spline nut is subjected to movement or movement trend in the direction away from the inner ring of the lead screw nut, the inner ring of the lead screw nut is subjected to movement or movement trend in the direction away from the inner ring of the spline nut, axial pretightening force can be applied to the inner ring and the outer ring of the spline nut, radial run-out of the inner ring of the spline nut is reduced, and meanwhile, axial pretightening force is applied to the inner ring and the outer ring of the lead screw nut, and radial run-out of the inner ring of the lead screw nut is reduced, so that the repeatability positioning precision of joints J3 and J4 of the SCARA robot is improved. On the other hand, the axial force generated by the load at the tail end of the spline of the ball screw is effectively dispersed to the spline nut by the magnetic force generated by the magnetic force device, so that the stress of the screw nut is reduced, and the service life of the screw nut is prolonged.
Drawings
FIG. 1 is a front view of an articulated robot (SCARA robot) of the present utility model;
fig. 2 is an enlarged view of a portion of the lead screw assembly of fig. 1.
The reference numerals are expressed as:
1. a base; 2. a first motor; 3. a first speed reducer; 4. a first mechanical arm; 5. a second speed reducer; 6. a second motor; 7. a second mechanical arm; 8. a third motor; 9. a fourth motor; 10. a screw rod; 11. a screw nut; 111. a screw nut inner ring; 112. an outer ring of the screw nut; 12. a spline nut; 121. a spline nut inner ring; 122. an outer race of the spline nut; 13. a first driving wheel; 14. a second driving wheel; 15. a first magnetic structure; 16. a second magnetic structure; 17. and (3) rolling balls.
Detailed Description
In the description of the present utility model, it should be noted that the azimuth or positional relationship indicated by the terms "inner", "outer", etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of describing the present utility model and simplifying the description, and are not indicative or implying that the apparatus or element in question must have a specific azimuth, be constructed and operated in a specific azimuth, and thus should not be construed as limiting the present utility model.
In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "contacting," and "communicating" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.
A first part: working principle of SCARA robot
As shown in fig. 1, the SCARA robot comprises a machine 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 rod nut 11 and a spline nut 12;
as shown in fig. 1, a first motor 2 is fixed on a base 1; the output shaft of the motor is connected with a first speed reducer 3; the input end of the first speed reducer 3 is connected with the output shaft of the first motor 2, and the output end of the first speed reducer is connected with the first mechanical arm 4; one end of the first mechanical arm 4 is connected with the output end of the first speed reducer 3. Under the deceleration action of the first speed reducer 3, the first motor 2 drives the first mechanical arm 4 and parts mounted on the first mechanical arm to rotate around the J1 shaft.
As shown in fig. 1, the second motor 6 is mounted on a second robot 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 deceleration action of the second speed reducer 5, the second motor 6 drives the second mechanical arm 7 and parts mounted on the second mechanical arm to rotate around the J2 shaft.
As shown in fig. 1, a third motor 8 is mounted on the second mechanical arm 7, the third motor 8 drives a screw nut 11, the screw nut 11 is assembled with a screw 10, and the screw 10 is controlled to reciprocate linearly along the J3 axis.
As shown in fig. 1, a fourth motor 9 is mounted on the second mechanical arm 7, the fourth motor 9 drives a spline nut 12 to rotate, the spline nut 12 is assembled with a screw rod 10, and the screw rod 10 can be controlled to rotate around the J4 axis under the cooperation of the screw rod nut 11.
A second part: working principle of J1 or J2 shaft of SCARA robot
The third motor 8 and the fourth motor 9 respectively drive the screw nut inner ring 111 and the spline nut inner ring 121 to enable the screw 10 to move up and down and rotate;
as shown in fig. 1-2, the lead screw nut 11 is composed of a lead screw nut inner ring 111 and a lead screw nut outer ring 112, and only one revolute pair exists between the lead screw nut outer ring 112 and the lead screw nut inner ring 111. The lead screw nut outer ring 112 is fixed with the lead screw nut mounting plate and is fixed on the second mechanical arm 7 together. The fit of the lead screw 10 and the lead screw nut inner ring 111 is a screw pair. The screw nut inner ring 111 is fixed with a screw nut belt wheel (a first driving wheel 13), and the third motor 8 drives the screw nut belt wheel to realize motion control of the screw nut inner ring 111.
As shown in fig. 1-2, the spline nut 12 is composed of a spline nut inner ring 121 and a spline nut outer ring 122, and only one revolute pair exists between the spline nut outer ring 122 and the spline nut inner ring 121. The spline nut outer ring 122 is fixed to the second arm 7. The screw rod 10 is in spline fit with the spline nut inner ring 121, and can axially move and can not rotationally move between the two. The spline nut inner ring 121 is fixed with a spline nut belt wheel (a second driving wheel 14), and the fourth motor 9 drives the spline nut belt wheel to realize motion control of the spline nut inner ring 121.
J3 axis motion: the rotational movement of the lead screw 10 is restricted (since the lead screw 10 and the spline nut inner ring 121 are spline-fitted, the rotation of the lead screw 10, that is, the rotational movement of the spline nut inner ring 121, the spline nut pulley (the second transmission wheel 14) is restricted). The spindle nut inner ring 111 is rotated, and the spindle nut inner ring 111 axially moves on the spindle 10 while rotating (because the spindle 10 and the spindle nut inner ring 111 are matched by screw pairs), however, because the spindle nut inner ring 111 axially moves is limited (because the spindle nut outer ring 112 is fixed with the second mechanical arm 7 and only a rotating pair exists between the spindle nut outer ring and the spindle nut inner ring 111), the axial movement of the spindle nut inner ring 111 on the spindle 10 is converted into the axial movement of the spindle 10 on the spindle nut inner ring 111.
J4 axis motion: when the screw 10 and the screw nut inner ring 111 rotate synchronously (i.e. the spline nut inner ring 121+the spline nut pulley (the second driving wheel 14) drives the screw 10, the screw 10 and the screw nut pulley rotate synchronously along with the screw nut inner ring+the screw nut pulley), the relative position between the screw 10 and the screw nut inner ring 111 will not change, and only rotational movement exists between the screw 10 and the screw nut inner ring 111 relative to the screw nut outer ring. The screw 10 thus has only a rotational movement, i.e. the J4 axis, relative to the second mechanical arm 7.
The J3 shaft and the J4 shaft are reasonably controlled to move together, so that the screw rod can move up and down while rotating.
Third section: the utility model relates to a spline shaft of a ball screw of a SCARA robot
As shown in fig. 1-2, the present utility model provides a screw assembly comprising:
the screw rod 10, the first driving wheel 13, the second driving wheel 14, the screw nut inner ring 111, the spline nut inner ring 121 and a magnetic force device, wherein the first driving wheel 13 can drive the screw nut inner ring 111 to rotate, the second driving wheel 14 can drive the spline nut inner ring 121 to rotate, the magnetic force device can generate magnetic force to enable the first driving wheel 13 and the second driving wheel 14 to generate force in opposite directions, further the spline nut inner ring 121 generates movement or movement trend in the direction far away from the screw nut inner ring 111, and the screw nut inner ring 111 generates movement or movement trend in the direction far away from the spline nut inner ring 121.
According to the utility model, by arranging the magnetic device, the first driving wheel and the second driving wheel are subjected to opposite force, so that the inner ring of the spline nut is subjected to movement or movement trend in the direction away from the inner ring of the lead screw nut, the inner ring of the lead screw nut is subjected to movement or movement trend in the direction away from the inner ring of the spline nut, axial pretightening force can be applied to the inner ring and the outer ring of the spline nut, radial run-out of the inner ring of the spline nut is reduced, and meanwhile, axial pretightening force is applied to the inner ring and the outer ring of the lead screw nut, and radial run-out of the inner ring of the lead screw nut is reduced, so that the repeatability positioning precision of joints J3 and J4 of the SCARA robot is improved. On the other hand, the axial force generated by the load at the tail end of the spline of the ball screw is effectively dispersed to the spline nut by the magnetic force generated by the magnetic force device, so that the stress of the screw nut is reduced, and the service life of the screw nut is prolonged.
In some embodiments, the magnetic device includes a first magnetic structure 15 and a second magnetic structure 16, the first magnetic structure 15 is integrally connected with the first driving wheel 13, the second magnetic structure 16 is integrally connected with the second driving wheel 14, and a magnetic repulsive force is generated between the first magnetic structure 15 and the second magnetic structure 16. The magnetic force device is in a preferable structural form, namely comprises a first magnetic structure and a second magnetic structure, and generates magnetic repulsive force between the first magnetic structure and the second magnetic structure, so that axial pretightening force is generated on the inner ring of the spline nut to reduce radial runout of the inner ring of the spline nut, and axial pretightening force is generated on the inner ring of the screw nut to reduce radial runout of the inner ring of the screw nut, and the repeatability positioning precision of J3 joint and J4 joint is improved; and the stress of the screw rod nut is reduced, and the service life of the screw rod nut is prolonged.
The utility model provides a ball screw assembly structure of a SCARA robot, which comprises a ball screw spline (screw rod, spline nut and screw rod nut), a spline nut belt wheel (namely a second driving wheel), a screw rod nut belt wheel (a first driving wheel), a first electromagnet (namely a first magnetic structure) and a second electromagnet (namely a second magnetic structure).
The spline nut outer ring and the screw nut outer ring are fixed;
the first electromagnet, the spline nut belt wheel and the spline nut inner ring are installed and fixed together and can rotate relative to the spline nut outer ring; the second electromagnet, the screw nut belt wheel and the screw nut inner ring are fixed together and can rotate relative to the screw nut outer ring.
Under certain conditions, the first electromagnet and the second electromagnet interact to generate opposite axial force, so that the inner ring and the outer ring of the spline nut and the inner ring and the outer ring of the screw nut generate opposite acting force, axial pre-tightening is realized, and radial runout is weakened.
The axial force from the load borne by the screw nut can be partially transferred to the spline nut by the interaction force generated by the first electromagnet and the second electromagnet, so that the stress of the balls between the inner ring and the outer ring of the screw nut is reduced to a certain extent.
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 form of construction of the first and second magnetic structures of the utility model, both of which may be permanent magnets or both of which are electromagnets or one of which is electromagnet and the other of which is permanent magnet, both of which are capable of generating a homopolar magnetic repulsive force.
In some embodiments, the first magnetic structure 15 is disposed on an end face of the first driving wheel 13 facing a side of the second driving wheel 14, and the second magnetic structure 16 is disposed on an end face of the second driving wheel 14 facing a side of the first driving wheel 13; the first magnetic structure 15 is opposite to and spaced apart from the second magnetic structure 16. The first magnetic structure and the second magnetic structure are further optimized in structure and position mode, are arranged oppositely and at intervals, can increase the strength of magnetic repulsive force between the first magnetic structure and the second magnetic structure, improve the axial pretightening force on the inner ring of the spline nut and the inner ring of the screw nut, further improve the repeatability positioning precision, and further reduce the stress of the screw nut.
In some embodiments, the first magnetic structure 15 and the second magnetic structure 16 are both annular structures, each allowing the screw 10 to pass therethrough. The first and second magnetic structures of the present utility model are further preferably both annular structures capable of allowing the screw to pass through so as to form a complete unitary structure.
As shown in fig. 1, when the end of the screw 10 is loaded, the force is transmitted from the screw 10 to the screw nut inner ring 111 to the ball 17 to the screw nut outer ring. Since the lead screw 10 is spline-fitted with the spline nut inner ring 121, there is an axial degree of freedom, and thus the force exerted by the load is entirely borne by the lead screw nut. The service life of the screw nut is reduced to a certain extent. Since there is play in the spline nut inner ring 121, the spline nut outer ring 122, and the ball fit between the two, there is some radial runout, which reduces the accuracy of repeated positioning to some extent.
The utility model therefore proposes a new SCARA robot ball screw spline shaft which is characterized by comprising a ball spline screw (screw rod 10+spline nut 12+screw rod nut 11), a spline nut pulley (second driving wheel 14), a screw nut pulley (first driving wheel 13), a first electromagnet (first magnetic structure 15) and a second electromagnet (second magnetic structure 16).
The second magnetic structure 16 is fixed to the inner spline nut ring 121 and the second driving wheel 14, and may be an electromagnet in some cases, or may be a permanent magnet in some cases, and generates an axial force with respect to the first magnetic structure 15 in an opposite direction. (the first and second electromagnets are always energized to generate repulsive force during operation)
The first magnetic structure 15 is fixed to the inner ring 111 of the lead screw nut and the first driving wheel 13, and may be an electromagnet in some cases, or may be a permanent magnet in some cases, and generates an axial force with opposite direction between the first magnetic structure and the second magnetic structure 16.
The first magnetic structure 15 and the second magnetic structure 16 are electromagnets or permanent magnets according to 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 and opposite acting force is generated between the first magnetic structure 15 and the second magnetic structure 16, the force can be changed according to the load situation, and the stress of the spline nut 12 and the lead screw nut 11 is uniform.
The gravity generated by the load is partially transferred to the spline nut assembly by the first 15 and second 16 magnetic structures. On the one hand, the stress condition of the screw nut 11 is relieved, on the other hand, when the force is transmitted to the spline nut inner ring 121, the axial pretightening force is applied to the spline nut 12, the play among the spline nut inner ring 121, the spline nut outer ring 122 and the balls 17 (the principle of applying the axial pretightening force by referring to the deep groove ball bearing) can be reduced, the radial runout is reduced, and the repeated positioning precision of the J3 and J4 shafts is increased to a certain extent.
By applying the axial pretightening force, radial play can be reduced, so that shaking of the screw rod in the radial direction is reduced, and the repeated positioning accuracy is improved. The concentration of the stable position is reached, i.e. the positioning accuracy is repeated.
In some embodiments, the screw-nut outer ring 112 is further included, the screw-nut outer ring 112 is sleeved on the outer periphery 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 further limits axial movement of the screw-nut inner ring 111, and the screw-nut inner ring 111 and the screw-nut outer ring 112 form a screw-nut 11;
an internal thread is arranged on the inner peripheral wall of the screw nut inner ring 111, an external thread is arranged on the outer peripheral wall of the screw rod 10, and the internal thread is matched and connected with the external thread, so that a matched screw pair is formed between the screw nut inner ring 111 and the screw rod 10, and the screw nut inner ring 111 can drive the screw rod 10 to axially move relative to the screw nut inner ring 111 and simultaneously rotate when being independently driven to rotate.
The screw nut is effectively formed by the structures of the screw nut inner ring and the screw nut outer ring, the screw nut outer ring is used for being fixed on the second mechanical arm to support the screw nut inner ring, the screw nut inner ring can rotate relative to the screw nut outer ring, namely, the screw nut inner ring is driven to rotate by the first driving wheel, the screw nut inner ring and the screw are connected through screw pairs, namely, the screw nut outer ring axially limits the screw nut inner ring, so that when the screw nut inner ring rotates, the screw is driven to rotate through the screw pairs and can also axially move (the screw nut inner ring is axially fixed), and the axial movement and rotation of the screw are realized; the inner wall of the inner ring of the screw rod nut is provided with an internal thread, and the corresponding position on the screw rod is provided with an external thread, so that the internal thread and the external thread are matched and connected, and the screw rod can be driven to rotate through the rotation of the inner ring of the screw rod nut and simultaneously can move up and down along the axial direction.
In some embodiments, the spline nut further comprises a spline nut outer ring 122, the spline nut outer ring 122 is sleeved on the 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 further limits axial movement of the spline nut inner ring 121, and the spline nut inner ring 121 and the spline nut outer ring 122 form a spline nut 12;
spline grooves are formed in the inner peripheral wall of the spline nut inner ring 121, splines are arranged on the outer peripheral wall of the screw rod 10 and are connected with the spline grooves in a matching mode, so that a matched revolute pair is formed between the spline nut inner ring 121 and the screw rod 10, the spline nut inner ring 121 drives the screw rod 10 to integrally rotate along with the spline nut inner ring 121 when being independently driven to rotate, and the screw rod 10 can axially move relative to the spline nut inner ring 121.
The spline nut is effectively formed by the structures 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, namely, the spline nut inner ring is driven to rotate by the second driving wheel, the spline nut inner ring and the screw rod are connected through a rotating pair, namely, spline connection is realized, and the spline nut inner ring is axially limited by the spline nut outer ring, so that when the spline nut outer ring rotates, the screw rod is driven to rotate only through the rotating pair (the spline nut inner ring is axially fixed), and the effective driving of the rotation of the screw rod is realized; and spline grooves are formed in the inner wall of the inner ring of the spline nut, and splines are arranged at corresponding positions on the screw rod, so that the splines are matched and connected with the spline grooves, the screw rod can be driven to only rotate through rotation of the inner ring of the spline nut, and the screw rod can move up and down along the axial direction relative to the inner ring of the spline nut.
The utility model also provides a robot which comprises the screw rod assembly.
In some embodiments, when the lead screw assembly further includes a lead screw nut outer race 112 and a spline nut outer race 122:
the robot further comprises a first mechanical arm 4 and a second mechanical arm 7, wherein one end of the first mechanical arm 4 is formed into a first rotating shaft, namely a J1 shaft, the first mechanical arm 4 can rotate around the J1 shaft, the other end of the first mechanical arm 4 is rotatably connected with one end of the second mechanical arm 7 to form a second rotating shaft, namely 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 driving wheel 13, the second driving wheel 14, the screw rod 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.
The horizontal screw rod assembly is in a further preferable structural form, a rotatable J1 shaft is formed at one end of the first mechanical arm, 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, the second mechanical arm can rotate around the J2 shaft, the J1 shaft and the J2 shaft are both rotated, the effect of rotating at a plurality of different positions can be achieved, and the degree of freedom and the degree of flexibility of the robot work are improved; the utility model further discloses a structure that the screw rod, the sleeve, the friction plate and the driving wheel are arranged at the other end of the second mechanical arm, so that the screw rod can be effectively controlled to rotate, namely rotate around the J4 shaft and axially move along the J3 shaft, the working freedom degree of the robot is further improved, and the spline and the screw nut outer ring are fixedly connected with the second mechanical arm, so that the spline and the screw nut inner ring are supported, and the screw rod is driven to rotate around the J4 shaft and/or axially move along the J3 shaft.
In some embodiments, a third motor 8 and a fourth motor 9 are further disposed on the second mechanical arm 7, the third motor 8 can drive the first driving wheel 13 to rotate, and the fourth motor 9 can drive the second driving wheel 14 to rotate; the first driving wheel 13 is a screw nut belt wheel, the second driving wheel 14 is a spline nut belt wheel, and the first driving wheel 13 and the second driving wheel 14 are simultaneously driven to rotate so as to drive the screw rod 10 to axially move and/or rotate. The horizontal screw rod assembly is in a further preferable structural form, namely, a third motor and a fourth motor are arranged on the second mechanical arm and are respectively used for driving the first driving wheel and the second driving wheel to rotate, so that the screw rod is effectively driven to axially move and rotate through the screw rod and the inner ring of the spline nut, and the aim of accurate control is achieved.
The utility model provides a SCARA robot, which can apply proper axial pretightening force to spline nuts on ball screw splines and inner and outer rings of the screw nuts, reduce radial runout of the ball screw nuts, and improve repeatability positioning accuracy of joints J3 and J4 of the SCARA robot. On the other hand, axial force generated by the load at the tail end of the ball screw spline is dispersed to the spline nut, so that the stress of the screw nut is reduced, and the service life of the screw nut is prolonged.
The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the utility model. The foregoing is merely a preferred embodiment of the present utility model, and it should be noted that it will be apparent to those skilled in the art that modifications and variations can be made without departing from the technical principles of the present utility model, and these modifications and variations should also be regarded as the scope of the utility model.
Claims (10)
1. A lead screw assembly, characterized in that: comprising the following steps:
lead screw (10), first drive wheel (13), second drive wheel (14), lead screw nut inner circle (111), spline nut inner circle (121) and magnetic means, first drive wheel (13) can drive lead screw nut inner circle (111) rotate, second drive wheel (14) can drive spline nut inner circle (121) rotate, magnetic means can produce magnetic force so that first drive wheel (13) with second drive wheel (14) produce the power of opposite direction, and then make spline nut inner circle (121) produce towards keeping away from movement or the motion trend of lead screw nut inner circle (111) direction, lead screw nut inner circle (111) produce towards keeping away from movement or the motion trend of spline nut inner circle (121) direction.
2. The screw assembly of claim 1, wherein:
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 driving wheel (13) into a whole, the second magnetic structure (16) is connected with the second driving wheel (14) into a whole, and magnetic repulsive force is generated between the first magnetic structure (15) and the second magnetic structure (16).
3. A screw assembly according to claim 2, 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.
4. A screw assembly according to claim 2, wherein:
the first magnetic structure (15) is arranged on the end face of the first driving wheel (13) facing one side of the second driving wheel (14), and the second magnetic structure (16) is arranged on the end face of the second driving wheel (14) facing one side of the first driving wheel (13); the first magnetic structure (15) is opposite to the second magnetic structure (16) and is arranged at intervals.
5. A screw assembly according to claim 2, wherein:
the first magnetic structure (15) and the second magnetic structure (16) are annular structures, and can allow the screw rod (10) to pass through the annular structures.
6. The screw assembly of claim 1, wherein:
the screw nut comprises a screw nut inner ring (111), and is characterized by further comprising a screw nut outer ring (112), wherein the screw nut outer ring (112) is sleeved on the periphery 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), and the screw nut inner ring (111) and the screw nut outer ring (112) form a screw nut (11);
the screw rod is characterized in that an inner thread is arranged on the inner peripheral wall of the screw rod nut inner ring (111), an outer thread is arranged on the outer peripheral wall of the screw rod (10), and the inner thread is matched and connected with the outer thread, so that a matched screw pair is formed between the screw rod nut inner ring (111) and the screw rod (10), and the screw rod nut inner ring (111) can drive the screw rod (10) to move axially and simultaneously rotate when being driven to rotate independently.
7. The lead screw assembly of claim 6, wherein:
the spline nut comprises a spline nut inner ring (121), and is characterized by further comprising a spline nut outer ring (122), wherein the spline nut outer ring (122) is sleeved on the 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) form a spline nut (12);
spline grooves are formed in the inner peripheral wall of the spline nut inner ring (121), splines are arranged on the outer peripheral wall of the screw rod (10), the splines are connected with the spline grooves in a matched mode, a matched revolute pair is formed between the spline nut inner ring (121) and the screw rod (10), the spline nut inner ring (121) is driven to integrally rotate along with the screw rod (10) when driven to rotate independently, and the screw rod (10) can axially move relative to the spline nut inner ring (121).
8. A robot, characterized in that: comprising a screw assembly according to any one of claims 1-7.
9. The robot of claim 8, wherein:
when the lead screw assembly further includes a lead 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), wherein one end of the first mechanical arm (4) is formed into a first rotating shaft, namely 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, namely 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 a screw rod (10), a first driving wheel (13), a second driving wheel (14), a screw rod nut inner ring (111) and a 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).
10. The robot of claim 9, wherein:
a third motor (8) and a fourth motor (9) are further arranged on the second mechanical arm (7), the third motor (8) can drive the first driving wheel (13) to rotate, and the fourth motor (9) can drive the second driving wheel (14) to rotate; the first driving wheel (13) is a screw nut belt wheel, the second driving wheel (14) is a spline nut belt wheel, and the first driving wheel (13) and the second driving wheel (14) are driven to rotate simultaneously so as to drive the screw rod (10) to axially move and/or rotate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223606662.2U CN218953949U (en) | 2022-12-30 | 2022-12-30 | Screw rod assembly and robot |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223606662.2U CN218953949U (en) | 2022-12-30 | 2022-12-30 | Screw rod assembly and robot |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218953949U true CN218953949U (en) | 2023-05-02 |
Family
ID=86136677
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202223606662.2U Active CN218953949U (en) | 2022-12-30 | 2022-12-30 | Screw rod assembly and robot |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218953949U (en) |
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2022
- 2022-12-30 CN CN202223606662.2U patent/CN218953949U/en active Active
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