CN220378812U - Ball screw structure and mechanical arm - Google Patents

Abstract

The utility model relates to the technical field of mechanical transmission, in particular to a ball screw structure and a mechanical arm, wherein the ball screw structure comprises a driving assembly, the driving assembly comprises a first shell and a motor, and the first shell is provided with an installation cavity; the motor comprises a rotor assembly and a stator, the stator is fixedly arranged in the mounting cavity, and the rotor assembly is arranged in the stator in a penetrating way; one end of the screw rod is fixedly inserted into the rotor assembly, and a screw nut is arranged on the screw rod; the rotary shaft of the incremental encoder is fixedly sleeved on the screw rod; the brake assembly comprises a second shell, and the other end of the screw rod is arranged in the second shell and can rotate relative to the second shell. The utility model can shorten the length, thereby reducing the weight of the lifting arm and ensuring the operation space and rigidity of the mechanical arm.

Description

Ball screw structure and mechanical arm

Technical Field

The utility model relates to the technical field of mechanical transmission, in particular to a ball screw structure and a mechanical arm.

Background

As shown in fig. 1, the laparoscopic surgical robot includes a drive box 1, a lift arm 2, a tool arm 3, an adjustment arm 4, an instrument 5, and the like, wherein the lift arm 2, the tool arm 3, and the adjustment arm 4 are mechanical arm portions.

The lifting arm 2 is close to the tail end of the mechanical arm of the laparoscopic surgery robot, the length and the weight of the lifting arm can have a great influence on the operation space and the rigidity of the mechanical arm, and the length of the lifting arm 2 directly influences the weight of the lifting arm.

In the prior art, the lifting arm 2 adopts a transmission mode that a ball screw is driven by a motor to run, the driving box 1 is driven to realize up-and-down running, and the running position of the lifting arm 2 is positioned, so that the running angle of the motor is monitored by a rotary encoder or the moving distance of a sliding block on a guide rail is monitored by a linear encoder. In addition, there may be components such as a brake and an incremental encoder on the lifting arm 2 for braking of the lifting mechanism and feedback of the motor operation.

The standard bases are arranged on two sides of the conventional ball screw structure and used for supporting the ball screw, and the locknut used for the pre-tightening bearing is arranged on the fixed supporting seat and is connected with the motor through the coupler. Likewise, the band-type brake and the encoder are also connected with the ball screw through a coupler. The use of the coupling results in an increase in the length of the entire lifting arm 2, and the weight of the lifting arm 2 increases, resulting in a decrease in the operating space and rigidity of the mechanical arm.

Therefore, a ball screw structure and a robot arm are required to solve the above-described problems.

Disclosure of Invention

The utility model aims to provide a ball screw structure and a mechanical arm, which can shorten the length, thereby reducing the weight of a lifting arm and ensuring the operation space and rigidity of the mechanical arm.

To achieve the purpose, the utility model adopts the following technical scheme:

a ball screw structure comprising:

a drive assembly including a first housing having a mounting cavity and a motor; the motor comprises a rotor assembly and a stator, the stator is fixedly arranged in the mounting cavity, and the rotor assembly is arranged in the stator in a penetrating way;

one end of the screw rod is fixedly inserted into the rotor assembly, and a screw nut is arranged on the screw rod;

the rotary shaft of the incremental encoder is fixedly sleeved on the screw rod;

the brake assembly comprises a second shell, and the other end of the screw rod is arranged in the second shell and can rotate relative to the second shell.

Further, the rotor assembly comprises an encapsulation piece and a rotor, the rotor is arranged on the encapsulation piece, the encapsulation piece is arranged in the stator in a penetrating mode, and the encapsulation piece is fixedly sleeved on the lead screw.

Further, a stop threaded hole is formed in the packaging piece, an external thread is formed in one end of the screw rod, and the screw rod is in threaded connection with the stop threaded hole.

Further, the first housing includes a first support base body, a first end cover and a second end cover, the motor is arranged in the first support base body, the first end cover and the second end cover are arranged on two ends of the first support base body, and the incremental encoder is arranged on the second end cover.

Further, a first support bearing is fixedly arranged in the mounting cavity, the lead screw is fixedly arranged in the inner ring of the first support bearing in a penetrating mode, and one end of the packaging piece is abutted to the inner ring of the first support bearing.

Further, still include band-type brake subassembly, band-type brake subassembly includes band-type brake coil and connecting axle, the fixed setting of band-type brake coil is in the second shell, the connecting axle wears to establish in the band-type brake coil, and with lead screw coaxial line connection, be provided with armature on the connecting axle, absolute value encoder's pivot passes through the connecting axle with lead screw coaxial line connection.

Further, a connecting hole is formed in one end, away from the driving assembly, of the screw rod, and one end of the connecting shaft is fixedly arranged in the connecting hole in a penetrating mode.

Further, the device also comprises an absolute value encoder which is arranged on one side of the second housing far away from the first housing, and a rotating shaft of the absolute value encoder is connected with the screw rod.

Further, the rotating shaft of the absolute value encoder is a hollow shaft, and the rotating shaft of the absolute value encoder is fixedly sleeved on one end of the connecting shaft.

The mechanical arm comprises an executing piece and the ball screw structure, wherein the executing piece is fixedly connected with a nut in threaded connection with a screw rod, and the screw rod can be driven to rotate so as to drive the nut to drive the executing piece to reciprocate along the axial direction of the screw rod

The utility model has the beneficial effects that:

according to the ball screw structure provided by the utility model, the motor is arranged in the mounting cavity of the first shell, the stator of the motor is fixedly arranged in the first shell, the rotor assembly of the motor is arranged in the stator in a penetrating way, one end of the screw rod is fixedly connected with the rotor assembly, the incremental encoder is fixedly arranged on the first shell, the rotating shaft of the incremental encoder is fixedly connected with one end of the screw rod, the other end of the screw rod is rotatably arranged in the second shell, and the absolute encoder is connected with the screw rod. Through with lead screw and rotor subassembly lug connection, the shaft coupling between lead screw and the motor has been cancelled, the shaft coupling between increment encoder and the lead screw has been cancelled, the locknut of ball screw fixing base to shorten the length of ball screw structure, reduce the weight of the lifting arm that uses ball screw structure, guarantee the operating space and the rigidity of arm.

The mechanical arm provided by the utility model comprises the ball screw structure, so that the length can be shortened, the weight of the lifting arm is reduced, and the operation space and the rigidity of the mechanical arm are ensured.

Drawings

FIG. 1 is a schematic view of a prior art laparoscopic surgical robot;

FIG. 2 is a schematic view of a ball screw structure according to the present utility model;

FIG. 3 is an exploded view of a first housing and screw in a ball screw configuration in accordance with the present utility model;

FIG. 4 is a cross-sectional view of a first housing in a ball screw configuration of the present utility model;

FIG. 5 is an exploded view of a second housing and screw in a ball screw configuration in accordance with the present utility model;

fig. 6 is a cross-sectional view of a second housing in a ball screw configuration of the present utility model.

In the figure:

1. a drive box; 2. a lifting arm; 3. a tool arm; 4. an adjustment arm; 5. an instrument;

21. a screw rod; 22. a first housing; 2201. a seal ring; 2202. a first end cap; 2203. a first support bearing; 2204. a first supporting seat body; 2205. a second end cap; 2206. a stator; 2207. a package; 2208. an incremental encoder; 2209. a second support bearing; 23. a second housing; 2301. a third support bearing; 2302. a second supporting seat body; 2303. a connecting shaft; 2304. band-type brake coil; 2305. supporting the end cover; 2306. a fourth support bearing; 2307. an absolute value encoder.

Detailed Description

The technical scheme of the utility model is further described below with reference to the attached drawings and the embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the drawings related to the present utility model are shown.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixed or removable, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. 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.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the process of designing the mechanical arm of the laparoscopic surgery robot, in order to shorten the length and thus reduce the weight of the lifting arm and ensure the operation space and rigidity of the mechanical arm, as shown in fig. 2-6, the utility model provides a ball screw structure. The ball screw structure includes a drive assembly, a brake assembly, a screw 21, and an incremental encoder 2208.

Wherein the drive assembly comprises a motor and a first housing 22, the first housing 22 having a mounting cavity; the motor includes a rotor assembly and a stator 2206, the stator 2206 being fixedly disposed in the mounting cavity, the rotor assembly being disposed through the stator 2206. One end of the screw 21 is fixedly inserted into the rotor assembly. The brake assembly comprises a second shell 23, the other end of the screw rod 21 is arranged in the second shell 23, the screw rod 21 can rotate relative to the second shell 23, and a screw nut is arranged on the screw rod 21; the incremental encoder 2208 is disposed at one side of the first housing 22, and a rotating shaft of the incremental encoder 2208 is fixedly sleeved on the screw 21.

Through with lead screw 21 and rotor subassembly lug connection, the shaft coupling between lead screw 21 and the motor has been cancelled, the shaft coupling between incremental encoder 2208 and the lead screw 21 has been cancelled, the locknut of ball screw fixing base to shorten the length of ball screw structure, reduce the weight of the lifting arm that uses the ball screw structure, guarantee the operating space and the rigidity of arm. The incremental encoder 2208 is an encoder capable of generating a signal based on the rotational movement of the screw 21, and performs incremental calculation for each pulse in a scale manner for measuring the linear movement. By adopting the incremental encoder 2208, the position of the screw on the screw 21 can be obtained according to the rotation angle of the screw 21, thereby realizing accurate control of the movement of the screw.

Further, the rotor assembly includes a package 2207 and a rotor, the rotor is disposed on the package 2207, the package 2207 is disposed in the stator 2206 in a penetrating manner, and the package 2207 is fixedly sleeved on the screw 21. By arranging the packing 2207, the installation of the rotor is facilitated, and the packing 2207 is directly connected with the screw 21, so that the installation of the screw 21 is facilitated. In the process of rotor rotation, the screw rod 21 can be directly driven to rotate without a coupler and a standard locknut.

Further, a stop threaded hole is formed in the packaging piece 2207, one end of the screw rod 21 is provided with an external thread, and the screw rod 21 is in threaded connection with the stop threaded hole. In order to prevent relative rotation between the screw 21 and the package 2207, a set screw is provided on the package 2207, and the set screw abuts against the screw 21, thereby preventing rotation.

Further, the first housing 22 includes a first support body 2204, a first end cover 2202 and a second end cover 2205, the motor is disposed in the first support body 2204, the first end cover 2202 and the second end cover 2205 are disposed on both ends of the first support body 2204, and the incremental encoder 2208 is disposed on the second end cover 2205. By designing the first housing 22 in three parts, installation of the motor, incremental encoder 2208 is facilitated. And after the fault occurs, the motor is convenient to overhaul or replace.

Further, a first support bearing 2203 is fixedly arranged in the mounting cavity, the lead screw 21 is fixedly arranged in an inner ring of the first support bearing 2203 in a penetrating manner, one end of the packaging piece 2207 is abutted to the inner ring of the first support bearing 2203, and sealing rings 2201 are arranged at two ends of the first support bearing 2203. Specifically, two first support bearings 2203 are arranged in parallel, the first support bearings 2203 are angular contact ball bearings, the sealing rings 2201 are lip-type sealing rings 2201, lubricating oil of the first support bearings 2203 can be prevented from leaking by arranging the sealing rings 2201, in the process of installing the first support bearings 2203, the inner ring of the first support bearings 2203 is abutted tightly in the process of connecting the screw rod 21 with the packaging piece 2207, and after the first end cover 2202 is installed, the outer ring of the first support bearings 2203 is fixed. Through setting up first support bearing 2203, can support lead screw 21, at lead screw 21 pivoted in-process, eliminate radial rocking, can reduce the friction moreover, guarantee lead screw 21 relative first shell 22 pivoted smoothness nature, first support bearing 2203 and first end cover 2202 cooperation limit the position of lead screw 21 moreover, avoid lead screw 21 to shift in the axial, guarantee that signature 21 is connected with the encapsulation 2207 is stable. In order to further ensure an effective support of the threaded spindle 21, a second support bearing 2209 is provided on the second end cap 2205, the threaded spindle 21 being arranged in the second support bearing 2209.

Further, the ball screw structure further comprises a band-type brake assembly, the band-type brake assembly comprises a band-type brake coil 2304 and a connecting shaft 2303, the band-type brake coil 2304 is fixedly arranged in the second housing 23, the connecting shaft 2303 penetrates through the band-type brake coil 2304 and is coaxially connected with the screw rod 21, an armature is arranged on the connecting shaft 2303, and a rotating shaft of the absolute value encoder 2307 is coaxially connected with the screw rod 21 through the connecting shaft 2303. Specifically, the brake coil 2304 is controlled to be powered on or powered off, so that the lead screw 21 can be controlled to stop or release the brake through the connecting shaft 2303. Because the connecting shaft 2303 is directly connected with the screw rod 21, a coupler between the screw rod 21 and the connecting shaft 2303 and a bearing at one end of the band-type brake are omitted, and the length of the ball screw structure can be further shortened while the function of the band-type brake is ensured. The absolute value encoder 2307 is fixedly connected with the screw 21 through a connecting shaft 2303, so that the absolute value encoder 2307 is convenient to install.

Further, a connecting hole is formed in one end, away from the driving component, of the screw rod 21, and one end of the connecting shaft 2303 is fixedly arranged in the connecting hole in a penetrating mode. The connecting shaft 2303 is matched with the connecting hole to realize rigid and fixed connection of the screw rod 21 and the connecting shaft 2303, so that the connecting shaft 2303 is convenient to install. In other embodiments, in order to prevent relative rotation between the screw 21 and the connection shaft 2303, a screw hole communicating with the connection hole may be formed in the screw 21, and a jackscrew may be mounted in the screw hole, and the jackscrew abuts against the connection shaft 2303 to prevent mutual rotation. In other embodiments, a connecting hole may be formed at one end of the connecting shaft 2303, and the end of the screw 21 away from the driving component is fixedly disposed in the connecting hole, which is not limited herein.

Further, an absolute value encoder 2307 is mounted on the second housing 23, the absolute value encoder 2307 is provided on a side of the second housing 23 away from the first housing 22, and a rotation shaft of the absolute value encoder 2307 is connected to the screw 21. The absolute value encoder 2307 can detect the rotation angle of the screw 21, so that the position of the nut on the screw 21 can be indirectly acquired. The absolute value encoder 2307 is matched with the incremental encoder 2208 together, so that the rotation angle of the screw 21 can be detected and verified, closed-loop control of screw rotation is realized, the accuracy of screw position control and detection is improved, and the risk caused by single fault is avoided.

Further, the rotation shaft of the absolute value encoder 2307 is a hollow shaft, and the rotation shaft of the absolute value encoder 2307 is fixedly sleeved on one end of the connection shaft 2303. With the above arrangement, the installation of the absolute value encoder 2307 is facilitated.

Further, the second housing 23 includes a second supporting seat body 2302 and a supporting end cover 2305, the band-type brake coil 2304 is fixedly disposed on the supporting end cover 2305 and is located in the second supporting seat body 2302, a third supporting bearing 2301 is disposed in the second supporting seat body 2302, and one end of the screw rod 21 is inserted into the third supporting bearing 2301. By providing the third support bearing 2301, the screw 21 can be supported separately, so that in the process of rotating the screw 21, the shake of the screw 21 in the radial direction is eliminated, and the fluency of the rotation of the screw 21 relative to the second housing 23 is ensured. The fourth support bearing 2306 is provided on the support end cap 2305, and the connection shaft 2303 is inserted into the fourth support bearing 2306, so that the smoothness of rotation of the connection shaft 2303 along with the screw 21 can be ensured by providing the fourth support bearing 2306.

Further, the lead of the lead screw 21 can be reduced, the output torque requirement of the motor and the braking torque requirement of the band-type brake assembly can be reduced, and the radial dimension and the axial dimension of the motor and the band-type brake assembly can be further reduced, so that the requirements of reducing the length, the width and the weight of the lifting arm can be met.

The embodiment also provides a mechanical arm, which comprises an executing piece and the ball screw structure, wherein the executing piece is fixedly connected with a screw nut in threaded connection with the screw rod, and the screw rod 21 rotates to drive the screw nut to drive the executing piece to reciprocate along the axial direction of the screw rod 21. The screw 21 is directly connected with the motor rotor, so that the length of the ball screw structure can be shortened, the weight of the lifting arm using the ball screw structure is reduced, and the operation space and the rigidity of the mechanical arm are ensured.

It is to be understood that the above examples of the present utility model are provided for clarity of illustration only and are not limiting of the embodiments of the present utility model. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the utility model are desired to be protected by the following claims.

Claims (10)

1. Ball structure, its characterized in that includes:

a drive assembly including a first housing having a mounting cavity and a motor; the motor comprises a rotor assembly and a stator, the stator is fixedly arranged in the mounting cavity, and the rotor assembly is arranged in the stator in a penetrating way;

one end of the screw rod is fixedly inserted into the rotor assembly, and a screw nut is arranged on the screw rod;

the rotary shaft of the incremental encoder is fixedly sleeved on the screw rod;

the brake assembly comprises a second shell, and the other end of the screw rod is arranged in the second shell and can rotate relative to the second shell.

2. The ball screw structure of claim 1, wherein the rotor assembly comprises a package and a rotor, the rotor is disposed on the package, the package is threaded into the stator, and the package is fixedly sleeved on the screw.

3. The ball screw structure according to claim 2, wherein the package is provided with a stop screw hole, one end of the screw is provided with an external thread, and the screw is screwed with the stop screw hole.

4. The ball screw structure of claim 1, wherein the first housing comprises a first support base body, a first end cap, and a second end cap, the motor is disposed in the first support base body, the first end cap and the second end cap are disposed on both ends of the first support base body, and the incremental encoder is disposed on the second end cap.

5. The ball screw structure according to claim 3, wherein a first support bearing is fixedly arranged in the mounting cavity, the screw is fixedly arranged in an inner ring of the first support bearing in a penetrating manner, and one end of the packaging piece is abutted with the inner ring of the first support bearing.

6. The ball screw structure according to any one of claims 1-5, further comprising a band-type brake assembly, wherein the band-type brake assembly comprises a band-type brake coil and a connecting shaft, the band-type brake coil is fixedly arranged in the second housing, the connecting shaft is arranged in the band-type brake coil in a penetrating manner and is coaxially connected with the screw, an armature is arranged on the connecting shaft, and a rotating shaft of the absolute value encoder is coaxially connected with the screw through the connecting shaft.

7. The ball screw structure according to claim 6, wherein a connecting hole is formed at one end of the screw, which is far away from the driving assembly, and one end of the connecting shaft is fixedly penetrated in the connecting hole.

8. The ball screw structure according to claim 6, further comprising an absolute value encoder provided on a side of the second housing remote from the first housing, and a rotation shaft of the absolute value encoder is connected to the screw.

9. The ball screw structure according to claim 8, wherein the rotating shaft of the absolute value encoder is a hollow shaft, and the rotating shaft of the absolute value encoder is fixedly sleeved on one end of the connecting shaft.

10. The mechanical arm is characterized by comprising an executing piece and the ball screw structure as claimed in any one of claims 1-9, wherein the executing piece is fixedly connected with a nut in threaded connection with a screw rod, and the screw rod can be driven to rotate so as to drive the nut to drive the executing piece to reciprocate along the axial direction of the screw rod.