CN220822813U

CN220822813U - Electric cylinder

Info

Publication number: CN220822813U
Application number: CN202322520612.0U
Authority: CN
Inventors: 张学成; 杨志刚
Original assignee: Beijing Chenyang Automation Technology Co ltd
Current assignee: Beijing Chenyang Automation Technology Co ltd
Priority date: 2023-09-15
Filing date: 2023-09-15
Publication date: 2024-04-19
Anticipated expiration: 2033-09-15

Abstract

The application provides an electric cylinder, which comprises a motor and a nut screw pair; the motor is a rotary motor and comprises a stator and a rotor; the rotor is of a hollow structure; the rotor is fixed with the nut of the nut screw pair or is formed by the nut of the nut screw pair; the outer edge of the nut screw pair is sleeved and fixed with a mounting sleeve; the stator is coaxially and cooperatively provided with a plunger cylinder at the outer edge thereof; the mounting sleeve and the plunger cylinder are radially and axially positioned and mounted at two ends through a pair of bearings; the cylinder barrel is sleeved on the outer side of the plunger barrel; the cylinder barrel is integrally fixed with a screw of the nut screw pair at one end of the cylinder barrel; an anti-rotation guide mechanism is arranged between the plunger cylinder and the cylinder barrel so as to prevent the plunger cylinder from rotating. The electric cylinder has compact and simple structure and small volume.

Description

Electric cylinder

Technical Field

The application relates to a linear actuator, in particular to an electric cylinder.

Background

The linear actuator is an important mechanical base part in the field of mechanical engineering and is widely applied to various industrial products. Among the linear actuators, an electric linear actuator, or an electric cylinder, is a new type of linear actuator that is in the spotlight. The common characteristics are that the motor is used as a power source, the rotary motion of the rotary motor is converted into linear motion through the conversion mechanism, and the thrust and the speed are output.

In order to increase the output thrust, the rotary motion of the motor is generally converted into linear motion with larger output thrust through a speed reducer, so that the structure of the electric cylinder is complex and the volume is large. There is an example in which the rotary motion of the motor is directly converted into output linear motion through a screw-nut mechanism to constitute an integrated electric cylinder, but the output stroke of such an electric cylinder is greatly limited due to the difficulty in machining the internal thread of the nut, and the general stroke is not more than 250mm. The output thrust is also small, and is difficult to be more than 50kN due to the lead limitation of the lead screw.

Disclosure of utility model

In view of the above, the present application aims to provide an electric cylinder which is compact.

The application relates to an electric cylinder, which comprises a motor and a nut screw pair; the motor is a rotary motor and comprises a stator and a rotor; the rotor is of a hollow structure; the method is characterized in that:

The rotor is fixed with the nut of the nut screw pair or is formed by the nut of the nut screw pair; the outer edge of the nut screw pair is sleeved and fixed with a mounting sleeve;

the stator is coaxially and cooperatively provided with a plunger cylinder at the outer edge thereof;

The mounting sleeve and the plunger cylinder are radially and axially positioned and mounted at two ends through a pair of bearings;

The cylinder barrel is sleeved on the outer side of the plunger barrel; the cylinder barrel is integrally fixed with a screw of the nut screw pair at one end of the cylinder barrel;

an anti-rotation guide mechanism is arranged between the plunger cylinder and the cylinder barrel so as to prevent the plunger cylinder from rotating.

Preferably, the anti-rotation guide mechanism is a linear rolling guide rail; the linear rolling guide rail comprises a guide rail body, a guide rail sliding block, a mounting seat and a mounting bar block;

The guide rail sliding block is fastened with the outer edge of the plunger cylinder through the mounting seat; the guide rail body is installed and fastened on the installation bar block, and is fastened on the cylinder barrel through the installation bar block.

Preferably, a plurality of anti-rotation guide mechanisms are provided between the plunger barrel and the cylinder barrel.

Preferably, two anti-rotation guide mechanisms are symmetrically arranged between the plunger barrel and the cylinder barrel.

The application relates to an electric cylinder, which comprises a motor and a nut screw pair; the motor is a rotary motor and comprises a stator and a rotor; the rotor is of a hollow structure;

A through hole is formed in the center of the screw rod of the nut screw rod pair, and an anti-rotation guide mechanism is arranged in the through hole;

One end of the anti-rotation guide mechanism is fastened with the stator.

Preferably, the anti-rotation guide mechanism is an optical axis and is in sliding fit with a through hole in the center of a screw of the nut screw pair.

Preferably, the anti-rotation guide mechanism is an optical axis, and a linear bearing is arranged in a through hole in the center of a screw rod of the nut screw rod pair; the optical axis is in sliding fit with the through hole through the linear bearing.

The electric cylinder adopts an integrated structure integrating the driving mechanism and the executing mechanism, so that the volume of the working device can be compact to the greatest extent, the mechanism is simplified, the space is saved, and the weight is reduced.

Drawings

FIG. 1 is a schematic diagram of the structural composition and operation of an electric cylinder of the present application;

FIG. 2a is a schematic view of the basic structure of the electric cylinder of the present application, and FIG. 2b is a schematic view of the sectional structure of the electric cylinder of the present application along the line A-A;

FIG. 3 is a schematic cross-sectional view of the electric cylinder of the present application along the line B-B;

FIG. 4 is a schematic diagram of the travel of the electric cylinder of the present application;

FIG. 5 is a schematic view of the installation of the anti-rotation mechanism of the electric cylinder of the present application on the plunger;

FIG. 6a is a schematic view of an anti-rotation mechanism of the electric cylinder of the present application; FIG. 6b is a schematic cross-sectional view of the electric cylinder of the application along line C-C;

FIG. 7 is a schematic diagram of another embodiment of the present application;

Fig. 8 is a schematic structural view of a further embodiment of the present application.

Detailed Description

The electric cylinder according to the present application will be described in detail with reference to the accompanying drawings.

The rolling screw nut pair 4 is positioned in the center of the working device, and the outer edge of the nut is sleeved with a fixed mounting sleeve 7. The mounting sleeve 7 is prevented from rotating relative to each other by means of a key on the nut, and axial positioning of the two is achieved by means of a shoulder and a tightening screw 71. The rotor of the motor 3 is arranged on the outer edge of the mounting sleeve 7; and the stator is sleeved outside the rotor. The outer edge of the stator is coaxially matched with the plunger barrel 5 and is fastened together. The plunger barrel 5 and the mounting sleeve 7 are mounted in radial and axial positioning by means of a pair of bearings 6. The bearing 6 must be able to withstand axial forces as well as radial forces. Depicted in fig. 1 as a pair of angular contact ball bearings. It can of course be any bearing that can withstand the load, achieve positioning, and meet the requirements of revolution.

In fig. 2a, for fastening the bearing, this is achieved by means of bearing caps 53 and 51 and fastening is performed by means of screws 52. This mounting ensures that the rotor and stator of the motor are coaxial and that the required air gap of the motor can be ensured.

The cylindrical outer edge of the plunger barrel 5 is connected with the cylinder barrel 2 through the anti-rotation guide mechanism 1. The anti-rotation guide mechanism 1 is used for preventing the plunger barrel 5 from rotating, but allowing the plunger barrel 5 to move in the axial direction. The anti-rotation guide mechanism 1 in fig. 2b is a linear rolling guide. The slide blocks of the guide rails are fastened with the outer edge of the plunger cylinder 5 through the mounting seat 12, and the slide blocks are fixed on the mounting seat 12. The guide rail is mounted and fastened on the mounting bar 11, and is fastened on the cylinder 2 by the mounting bar 11. The cylinder barrel 2 is fastened with one end of a screw rod of the rolling screw nut pair 4 through the end cover 21 and the expansion sleeve 22, and the fastening ensures that the screw nut pair and the motor are concentric.

For the connection of the motor wires, a socket 23 is mounted on the cylinder 2. To accommodate the wires, sufficient space is left between the end cap 21 and the bearing cap 53.

More than 1 anti-rotation guide may be mounted in the circumferential direction, as in fig. 2b another anti-rotation guide is mounted in the diagonal direction. In the axial direction, the guide anti-rotation mechanism needs a sufficient length to meet the output stroke length of the plunger barrel 5. As in fig. 2a, 3, a linear guide mechanism is provided with two slides. The distance l taken by the two sliders, as shown in fig. 4, should meet multiple requirements for positioning, lateral force bearing and guiding. If two sliders are insufficient, a plurality of sliders may be additionally installed. The anti-rotation guide mechanism is arranged on the cylinder barrel and the plunger barrel, and the structure schematic diagram is shown in fig. 5. The anti-rotation guide mechanism 1 is a set of linear guide rails. The slider is mounted on a slider mount 12 which is in turn mounted in a blind slot 54 on the outer edge of the plunger barrel 5. The effect after installation is that the direction of movement of the guide rail is parallel to the axis of the plunger barrel 5. If two sets of guiding anti-rotation mechanisms are installed, the two sets of guiding anti-rotation mechanisms are symmetrically installed on the other side of the outer edge of the plunger barrel 5. The installation of the guide anti-rotation mechanism 1 on the cylinder is shown in fig. 6 a. The guide rails of the guide anti-rotation mechanism are mounted on guide rail mounting bars 11, and they (guide rail mounting bars 11, guide rail slider, slider mount 12) enter from the radial direction of the cylinder as a whole and are mounted and fixed. The guide rail mounting bar block is fixed on the cylinder barrel 2 through a screw, and the slide block mounting seat 12 is fixedly arranged on the plunger barrel 5.

The stroke length L of the working device is only required to be appropriately increased depending on the application requirements. The length of the working device, the minimum value is mainly determined by the length of the motor and other auxiliary devices in the device.

The end of the cylinder 2 is provided with a dust-proof and mechanical limit cap 24.

In order to prevent possible screw oscillation, a radial limit bearing is arranged at the other end of the screw and ensures axial positioning. The figures use shoulders and circlips for positioning. The radial limit bearing is a deep groove ball bearing, and the outer circular surface of the radial limit bearing is in sliding contact with the inner circular surface of the rotor mounting sleeve. Namely, when the mounting sleeve 7 and the plunger barrel 5 move linearly together, the outer ring of the radial limiting bearing moves relative to the inner circular surface of the rotor mounting sleeve.

When in operation, the rotor of the motor 3 drives the nut of the screw-nut pair 4 to do rotary motion, and the angular velocity omega; the screw-nut pair 4 rotates around a screw fixed with the cylinder barrel 2 and simultaneously moves linearly (the movement direction is determined by the rotation direction of the motor and the rotation direction of the screw thread); the motor 3 as a whole, the rotation of the rotor, through the bearing 6, causes a rectilinear movement of the whole motor 3 along the screw, and therefore of the stator of the motor. The output plunger 5, which is fixed with the stator of the motor, moves linearly with the stator of the motor at a speed v. The stator of the motor and the output plunger 5 can only move linearly and cannot rotate due to the constraint of the anti-rotation guide mechanism 1.

The cylinder 2 and the output plunger 5 are a pair of relatively straight moving members, and one is assumed to be a fixed end, and the other is an output end. However, when the output is used for high-speed and high-frequency motion output, the output plunger body is used as a fixed end, and the cylinder barrel is used as a motion end, so that the influence of vibration and acceleration of the motor and related components in the plunger body can be reduced.

In particular, the motor may be a plurality of motors connected in series to constitute a power source with a larger power and a larger torque output, because of the need for a simple length production.

In particular, another embodiment of the integrated electric cylinder is shown in fig. 7. Its composition and movement relationship is substantially similar to the device described above, but the end of the screw is loaded, and the screw typically acts as the output member. The obvious difference is that the screw is provided with an inner hole for installing an anti-rotation and guiding mechanism. The anti-rotation and guiding mechanism is fixed together with the motor stator at the end. When the device works, the screw rod moves linearly along the guiding and anti-rotation mechanism. The guiding and anti-rotation mechanism can be a sliding fit of an optical axis and a central hole of the screw rod, or can be a linear bearing arranged in the screw rod hole, and any mechanism with the guiding and anti-rotation functions. The lead screw as the output member is provided with a special protection device as necessary to prevent contamination, dust, and the like. The structure has the advantages that under certain conditions, the outline size can be smaller, namely more compact; the screw and nut pair with larger specification can be used for overcoming the load and reducing the requirement on the performance of the screw. The defects are that the center through hole of the filament lever is difficult to process, and the installation mechanism is not easy; the rigidity of the anti-rotation mechanism is reduced during a long stroke; the screw needs special protection to avoid dust and pollution.

Another particular example is:

An electric cylinder using a circulating planetary roller screw is shown in fig. 8. Unlike the electric cylinder described above, only the lead screw 4 is replaced with a planetary roller lead screw. This embodiment is to increase the output carrying capacity. In particular, planetary roller screws, such as circulating planetary roller screws and differential planetary roller screws, can be used, and the actual lead of the planetary roller screws is far smaller than the physical lead, so that the planetary roller screws have large bearing capacity and are equivalent to a speed reducer. As with the ball screw having a minimum lead of 20mm for a dynamic load of 190kN, the lead of the roller screw is only 1mm, which corresponds to a speed reducer employing a reduction ratio of 20.

The electric cylinder of the application has the following advantages:

1. The integrated structure integrates the driving mechanism and the executing mechanism, so that the volume of the working device can be compact to the greatest extent, the mechanism is simplified, the space is saved, and the weight is reduced.

2. The travel of the working device is not limited as long as the length of the screw allows. The problems that the internal thread is difficult to process and the length is difficult to be large, so that a large stroke cannot be realized are solved.

3. By adopting a proper anti-rotation guide mechanism, the problems of output friction and protection of the plunger are avoided, and the processing amount can be reduced. Because the motor stator and cylinder are coupled together by the anti-rotation guide mechanism, at least costly heat treatment and finishing steps, including motor stator outer surfaces, plunger outer surfaces, are not required.

4. And a special reverse type screw rod is not required, and any type screw rod can be adopted, so long as the cost performance is reasonable. Therefore, the structure of the screw rod is simplified, and the cost is reduced.

5. The electric cylinder only needs to be connected with a wire, and can be like a hydraulic cylinder: the hydraulic oil cylinder has the advantages of similar appearance, similar movement relation, even higher performance index, lower cost and suitability for the needs of the electric age, but completely avoids the problems of complex structure, difficult maintenance, low efficiency, leakage, noise, huge oil source system, complex oil pipe connection and the like of the hydraulic oil cylinder.

6. By adopting the small-lead planetary roller screw, a speed reducer can be omitted, high thrust output can be realized, and the stroke can be unrestricted. The small lead screw can have the performance of large bearing capacity and high mechanical efficiency.

Unless defined otherwise, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application relates. The materials, methods, and examples mentioned herein are illustrative only and not intended to be limiting.

Although the present application has been described in connection with specific embodiments thereof, those skilled in the art will appreciate that various substitutions, modifications and changes may be made without departing from the spirit of the application.

Claims

1. An electric cylinder comprises an electric motor and a nut screw pair; the motor is a rotary motor and comprises a stator and a rotor; the rotor is of a hollow structure; the method is characterized in that:

2. The electric cylinder according to claim 1, characterized in that:

The anti-rotation guide mechanism is a linear rolling guide rail; the linear rolling guide rail comprises a guide rail body, a guide rail sliding block, a mounting seat and a mounting bar block;

3. The electric cylinder according to claim 2, characterized in that:

a plurality of anti-rotation guide mechanisms are arranged between the plunger cylinder and the cylinder barrel.

4. A cylinder as claimed in claim 3, wherein:

two anti-rotation guide mechanisms are symmetrically arranged between the plunger cylinder and the cylinder barrel.

5. An electric cylinder comprises an electric motor and a nut screw pair; the motor is a rotary motor and comprises a stator and a rotor; the rotor is of a hollow structure; the method is characterized in that:

One end of the anti-rotation guide mechanism is fastened with the stator.

6. The electric cylinder according to claim 5, characterized in that:

the anti-rotation guide mechanism is an optical axis and is in sliding fit with a through hole in the center of a screw rod of the nut screw rod pair.

7. The electric cylinder according to claim 5, characterized in that:

The anti-rotation guide mechanism is an optical axis, and a linear bearing is arranged in a through hole in the center of a screw rod of the nut screw rod pair; the optical axis is in sliding fit with the through hole through the linear bearing.