CN112706187A

CN112706187A - Normally open type pneumatic flexible spherical brake

Info

Publication number: CN112706187A
Application number: CN201911029895.0A
Authority: CN
Inventors: 武广斌; 耿德旭; 刘洪波; 赵云伟; 刘齐
Original assignee: Beihua University
Current assignee: Beihua University
Priority date: 2019-10-25
Filing date: 2019-10-25
Publication date: 2021-04-27
Anticipated expiration: 2039-10-25
Also published as: CN112706187B

Abstract

The invention discloses a normally open type pneumatic flexible spherical brake, which belongs to a mechanical braking device and is used for a robot joint or a small braking device; the brake can solve the problems of large volume, inflexibility, single braking direction and the like of the conventional mechanical, hydraulic, electromagnetic and combined braking system; the structure is characterized in that the brake is provided with a left hemispherical ball seat and a right hemispherical ball seat which share a spherical center, a spherical brake framework, a mandrel, a drum-shaped driving air bag, a floating brake plate and other parts; the brake braking force is generated by pressure fluid filled in the drum-shaped driving air bag; the drum-shaped driving air bag pushes the floating brake plate and the ball seat to generate acting force, so that the aim of multi-directional space braking is fulfilled; the braking force of the brake is determined by the pressure of the charged fluid; the brake is in a non-braking state when not working; the preset of the joint torque can be realized through the adjustment of the braking torque.

Description

Normally open type pneumatic flexible spherical brake

Technical Field

The invention relates to a pneumatic flexible brake with a pose keeping function, which is used on a robot wrist and a joint.

Background

The robot technology is widely applied in the fields of industry, military, medical treatment and the like, and is one of the national important strategic technologies; the flexibility and the accuracy of the operation of the robot are determined by the robot arm and the joint, and the braking performance of the robot arm and the joint influences the positioning precision and the pose maintaining capability of the end effector; the current driving mode of the robot joint brake mainly comprises the following steps: hydraulic, electromagnetic, pneumatic, and the like; the hydraulic brake has larger braking torque, is mainly used for heavy robot joints, but has larger volume and needs huge hydraulic systems and equipment; the electromagnetic brake has larger volume, difficult adjustment of braking torque and inflexible application; the pneumatic brake has compact structure, convenient control and cleaning, and is widely used at present; a brake which has space pose holding capacity, can realize multidirectional space braking and has adjustable braking torque is urgently needed so as to meet the special requirements of the structure, the braking performance and the control requirement of the brake of a robot joint.

Disclosure of Invention

The invention aims to solve the problems of uncontrollable braking torque and multidirectional space braking of the current brake, and provides a brake capable of realizing joint space pose keeping and braking functions; the brake consists of a spherical floating brake device and a drum driver; the spherical floating brake device is characterized in that the spherical floating brake device is arranged between the upper flange and the lower flange of the brake, and the central axis of the spherical floating brake device is positioned on the geometric center connecting line of the upper flange and the lower flange of the brake; the spherical floating brake device is composed of a plurality of adjusting bolts, nuts, a left hemispherical ball seat, a right hemispherical ball seat, an upper limit end cover, a lower limit end cover, a fixed nut, a gasket, a core shaft, a floating brake plate and a spherical brake framework; through holes which are uniformly distributed are reserved in the geometric center position of the lower flange of the brake, and the lower flange is fixedly connected to threaded holes which are uniformly distributed in the bottom of the framework of the spherical brake by bolts, so that the central axis of the framework of the spherical brake is superposed with the connecting line of the geometric centers of the upper flange and the lower flange; the spherical brake framework is a hollow-out multi-half spheroid, the upper edge of the spherical brake framework is provided with a circular platform for positioning the assembly position of the upper limit end cover, four same trapezoidal windows are uniformly and symmetrically distributed on the multi-spheroid, and an arc-shaped upright post is formed between the adjacent windows; the cross section of the arc-shaped upright post is a T-shaped section; the narrow end of the arc-shaped upright post faces outwards, and the wide end faces inwards; a floating brake plate with the same shape as the trapezoidal window is arranged between two adjacent arc T-shaped stand columns; the two adjacent arc T-shaped stand columns can limit the floating brake plate to move towards the center of the sphere along the radial direction, so that the floating brake plate can only move away from the center of the sphere along the radial direction; the floating brake plate has a thin spherical surface sheet body with the appearance consistent with that of windows uniformly distributed on a spherical brake framework, the body structure of the floating brake plate is a part of a spherical surface, and the diameter of the floating brake plate is the same as that of the spherical brake framework; the position of the spherical center of the floating brake plate after installation is superposed with the position of the spherical center of the spherical brake framework; the central position of the lower end of the spherical brake framework is provided with a threaded hole, the central position is fixedly connected with a mandrel by adopting threads, the central axis of the mandrel is superposed with the central axis of the spherical brake framework, the mandrel is provided with threads at two ends of a stepped shaft, and the lower end threads are connected with the central threaded hole of the spherical brake framework and limit the axial movement of the mandrel; the mandrel is fixed on the spherical brake framework; a lower limiting end cover is arranged on a shaft shoulder at the lower end of the mandrel, and the lower limiting end cover is parallel to the lower flange after installation; an upper limiting end cover is arranged on a shaft shoulder at the upper end of the mandrel, and the upper limiting end cover is parallel to the lower flange after installation; the drum-shaped driving air bag is arranged between the upper limit end cover and the lower limit end cover and is characterized in that the drum-shaped driving air bag is a drum-shaped thin-wall hollow high-elasticity bag body, the end faces of the upper end and the lower end of the drum-shaped driving air bag are parallel, four grooves are arranged in the radial direction, and the width and the phase position of each groove are the same as the width of the inner side of the arc-shaped stand column; when the drum-shaped driving air bag is installed, the groove is assembled on the arc-shaped upright post, and the arc-shaped upright post is used for limiting the circumferential deformation and displacement of the drum-shaped driver; the outer sides of the floating brake plate and the spherical brake framework are provided with brake ball seats, and each brake ball seat is composed of a left hemispherical brake ball seat and a right hemispherical brake ball seat; the left and right half ball brake ball seats are provided with adjusting gaskets and bolts; the brake ball seat is in clearance fit with the spherical brake framework, and a movement clearance is reserved between the floating brake plate and the left and right hemispherical brake ball seats; the upper end of the left and right hemispherical brake ball seats is fixed with a brake upper flange; the bottom of the drum-shaped driving air bag is provided with a gas inlet; when the pressure of the charged gas is increased, the drum-shaped driving air bag expands and deforms, the axial deformation of the drum-shaped driving air bag is restrained, and only the radial expansion deformation is realized; the radial expansion deformation pushes the floating brake plate to brake the ball seat to move outwards along the radial direction; when the pressure reaches a certain value, the floating brake plate is contacted with the left and right hemispherical brake ball seats on the outer side; when the charging pressure is continuously increased, the positive pressure of the floating brake plate on the left and right hemispherical brake ball seats on the outer side is increased, the friction force between the floating brake plate and the ball seats is increased, and the braking force is increased; when the normally open type pneumatic flexible spherical brake is in a working state, the brake has good braking effect on the axial torque, the radial torque and the resultant torque; when the pressure of the charged gas is reduced, the drum-shaped driving air bag resets under the elastic acting force of the drum-shaped driving air bag; therefore, the positive pressure of the floating brake plate on the left and right hemispherical brake ball seats at the outer side is reduced, the friction force between the floating brake plate and the ball seats is reduced, the braking force is reduced until the braking force is reduced to zero, and the braking function is lost; according to the working requirement, the brake torque of the brake can be adjusted by adjusting the input air pressure of the drum-shaped driving air bag; the invention has the advantages that the brake has small volume, flexible movement and adjustable braking torque, and can brake in multiple directions; the device can adapt to the working states of different loads; the method has great popularization and application values in the application fields of bionic robots, special equipment and the like, and has good development prospects.

Drawings

FIG. 1 is a sectional view of the general structure of a normally open type pneumatic flexible ball brake;

FIG. 2 is an exploded view of a normally open pneumatic flexible ball brake;

Detailed Description

The invention is described in further detail below with reference to the following figures and specific examples:

as shown in fig. 1, the invention provides a normally open type pneumatic flexible spherical brake, which is provided with a left hemispherical brake ball seat 3, a right hemispherical brake ball seat 6, an upper limit end cap 10, a drum-shaped driving air bag 11, a lower limit end cap 12, a mandrel 13, a floating brake plate 14, a spherical brake framework 15, a plurality of connecting bolts, nuts and gaskets; connecting the bottom end threaded shaft of the mandrel 13 to the central threaded hole at the lower end of the spherical brake framework 15, so that the spherical center of the spherical brake framework 15 is coincided with the central axis of the mandrel 13; a central hole of the lower limiting end cover 12 penetrates through the mandrel 13 and is assembled on a shaft shoulder at the bottom of the mandrel 13; the end face of the lower limit end cover 12 is ensured to be parallel to the end face of the bottom of the spherical brake framework 15; mounting the drum drive airbag 11 to the central position of the mandrel 13 through the central hole of the drum drive airbag 11, and the drum drive airbag 11 is positioned above the lower limit end cover 12; four grooves which are uniformly distributed on the drum-shaped driving air bag 11 are respectively arranged on four arc-shaped stand columns of the spherical brake framework 15, and the arc-shaped stand columns limit the drum-shaped driving air bag 11 not to circumferentially rotate; mounting the upper limit end cover 10 above the drum-shaped driving air bag 11, and enabling the shoulder surface of the upper limit end cover 10 to be superposed with the cross section of the upper end surface of the spherical brake framework 15; the bottom surface of the boss of the upper limit end cover 10 sinks below the cross section of the upper end surface of the spherical brake framework 15; assembling the gasket 9 on the mandrel 13 and installing the gasket above the upper limit end cover 10; a nut 8 is used for locking the fixing gasket 9 and the upper limiting end cover 10; installing a floating brake plate 14 in a groove formed by assembling a spherical brake framework 15 and a drum-shaped driving air bag 11 by adopting a clearance fit method; the left hemisphere braking ball seat 3, the right hemisphere braking ball seat 6, the positioning pin 5, the adjusting bolt 7 and the adjusting pad 4 form a braking ball seat; the braking ball seat is arranged on the outer sides of the spherical brake framework 15 and the floating brake plate 14, and the braking ball seat is assembled with the spherical brake framework 15 and the floating brake plate 14 in a clearance fit manner; the adjusting bolt 7 and the adjusting gasket 4 can adjust the gap between the ball seat and the spherical brake framework 15; when the ball seats are assembled, the coincidence of the ball centers of the left hemisphere braking ball seat 3 and the right hemisphere braking ball seat 6 with the spherical brake framework 15 needs to be ensured; the upper flange 2 and the lower flange 16 of the domestic brake are connected by bolts.

Claims

1. A normally open type pneumatic flexible spherical brake is characterized in that a spherical floating brake device is arranged on the central axis of an upper flange and a lower flange; the spherical floating brake device consists of a ball seat and a ball head; the ball seat is composed of a spherical thin-wall left half ball seat, a spherical thin-wall right half ball seat, a plurality of bolts and an adjusting gasket; the ball head consists of an upper limit end cover, a drum-shaped driving air bag, a lower limit end cover, a stepped mandrel, a floating brake plate and a spherical brake framework; a central hole of the drum-shaped driving air bag penetrates into the stepped mandrel, an upper limiting end cover and a lower limiting end cover are respectively arranged at the upper end and the lower end of the drum-shaped driving air bag, the top of the upper limiting end cover is fastened by a gasket and a nut, the other end of the mandrel is fixed on a central threaded hole at the bottom of an internal cavity of the spherical brake framework by threads, and a plurality of floating brake plates are uniformly distributed at the window of the spherical brake framework; the ball seat and the ball head are assembled in a clearance fit manner, and after assembly, the ball centers of the ball seat and the ball head are superposed and are positioned on the central axis of the upper flange and the lower flange; the size of the gap between the ball seat and the ball head can be adjusted through the adjusting gasket and the adjusting bolt; after the driving air bag is filled with pressure gas, the floating brake plate is pushed to press the ball seat by radial expansion, and braking force is generated.

2. The normally open pneumatic flexible spherical brake of claim 1, wherein the spherical brake skeleton is a hemispherical hollow metal part; the top of the spherical brake framework is a torus, a plurality of arc-shaped stand columns are uniformly distributed below the torus, the cross sections of the stand columns are of a T-shaped structure, the narrow surface ends of the arc-shaped stand columns are positioned on the peripheral surface of the spherical brake framework, and the wide surface ends are positioned on the inner side surface of the spherical brake framework; a plurality of trapezoidal windows with the same shape are formed on the upper end surface and the lower end surface of the two arc-shaped positioning columns and the framework of the spherical brake; the bottom of the spherical brake framework is provided with a threaded hole, and the central axis of the threaded hole is superposed with the central axis of the spherical brake framework and used for connecting threads at the bottom of the mandrel; mounting threaded holes are distributed around the central threaded hole and used for connection and fixation; a through hole is formed in the middle of the two fixing threaded holes and used for allowing a fluid pipeline to pass through; the skeleton can be made of carbon steel, aluminum alloy, engineering plastics and composite materials.

3. The normally open pneumatic flexible ball brake of claim 1, wherein the floating brake plate is a laminar spherical surface plate; the size of the outer shape of the brake is the same as that of the window on the spherical brake framework; the ball-shaped surface of the floating brake plate body has the same radius as the outer spherical surface of the ball brake.

4. The normally open pneumatic flexible ball brake of claim 1, wherein the number of the floating brake plates is the same as the number of the framework windows, and can be 2, 3, 4, 5 or 6; can be made of carbon steel, aluminum alloy, engineering plastics and composite materials.

5. The normally open pneumatic flexible spherical brake as claimed in claim 1, wherein the drum-shaped driving air bag is a pressure-resistant drum-shaped hollow thin-wall high-elasticity single bag body, the shape of which is the same as that of the framework inner cavity, and the bottom of the bag body is provided with a vent hole; a through hole is arranged between the upper end surface and the lower end surface of the drum-shaped driving air bag, and the diameter of the through hole is the same as that of the mandrel; grooves with the same number as the arc-shaped upright columns on the framework of the spherical brake are arranged on the spherical surface between the upper end surface and the lower end surface of the drum-shaped driving air bag, and the width of each groove is the same as the size of the wide end of each arc-shaped upright column; can be made of elastic materials such as latex, rubber, silica gel, AB glue and the like.