CN115217868B

CN115217868B - Electromagnetic brake and robot

Info

Publication number: CN115217868B
Application number: CN202210634133.9A
Authority: CN
Inventors: 陈显威; 沈晓龙
Original assignee: Shenzhen Tongchuan Technology Co ltd
Current assignee: Shenzhen Tongchuan Technology Co ltd
Priority date: 2022-06-07
Filing date: 2022-06-07
Publication date: 2024-10-01
Anticipated expiration: 2042-06-07
Also published as: CN115217868A

Abstract

An electromagnetic brake, comprising: a main shaft; the brake body is sleeved on the main shaft and is provided with an armature; the brake disc comprises a tray and a friction plate, the tray is fixedly connected to the main shaft, the friction plate is fixedly connected to the tray, and the friction plate is partially exposed out of the tray; the brake body drives the armature to be close to or far away from the friction plate, the brake body pushes out the armature, and the armature is in single-sided abutting connection with the friction plate and is braked. The application combines the friction plate and the tray into a whole to form the brake disc, and the brake disc is directly fixedly connected on the main shaft to prevent friction noise and dust from being generated due to the movement of the brake disc along the main shaft, and simultaneously, the friction surface of the brake during braking is adjusted to be one side of the friction plate, so that the dust amount generated during friction is further reduced.

Description

Electromagnetic brake and robot

Technical Field

The invention relates to the technical field of brakes, in particular to an electromagnetic brake and a robot.

Background

With the rapid development of industrial automation technology, industrial robots are becoming more and more important as an important industrial automation device, and are being used more and more widely. In the related technology of industrial robots, the control of moving parts such as joints of the cooperative robots is the most important and critical, so the design of an electromagnetic brake is also gradually paid attention to, the electromagnetic brake is a connector for transmitting the torque force of an active side to a passive side, and can be freely combined, separated or braked according to the requirement, and the electromagnetic brake has a plurality of specific implementation advantages, is an ideal automatic executing element in the modern industry, and mainly plays roles of transmitting power, controlling movement and the like in a mechanical transmission system.

In the prior art, an electromagnetic brake is used as a gesture maintaining component when the robot joint and a servo motor act and are powered off, a rotor part of the electromagnetic brake needs to rotate along with a motor shaft, but simultaneously the electromagnetic brake needs to be capable of axially moving, so that the problems of loud noise, much friction dust (the rotor moves along the axial direction and rubs with an armature), big space size and the like can occur when the traditional brake runs on a machine.

Disclosure of Invention

Accordingly, it is necessary to provide an electromagnetic brake and a robot, which solve the problems of high noise and high friction dust of the electromagnetic brake.

An electromagnetic brake, comprising:

A main shaft;

The brake body is sleeved on the main shaft and is provided with an armature; and

The brake disc comprises a tray and a friction plate, wherein the tray is fixedly connected to the main shaft, the friction plate is fixedly connected to the tray, and the friction plate is partially exposed out of the tray;

The brake body drives the armature to be close to or far away from the friction plate, the brake body pushes out the armature, and the armature is in single-sided abutting connection with the friction plate and is braked.

In one embodiment, the annular array of the brake body is provided with a plurality of guide posts, the guide posts are fixedly connected with the brake body, and the armature is in sliding connection with the guide posts.

In one embodiment, the guide post comprises a sliding body fixedly connected to the brake body and a limiting body integrally formed at the top of the sliding body, the sliding body is in sliding connection with the armature, an elastic piece is sleeved on the sliding body, and the elastic piece is respectively abutted to the brake body and the armature.

In one embodiment, the outer peripheral diameter of the limiting body is larger than the outer peripheral diameter of the sliding body, the length of the sliding body is larger than the thickness of the armature, and the plane height of the limiting body is larger than or equal to the plane height of the friction plate.

In one embodiment, the brake further comprises a bearing, wherein an inner ring of the bearing is sleeved on the main shaft, and an outer ring of the bearing is fixedly connected inside the brake body.

In one embodiment, the brake body is provided with a connector lug, and the connector lug is electrically connected with an external circuit.

In one embodiment, the outer periphery of the brake body is provided with a plurality of first notches, the outer periphery of the armature is provided with a plurality of second notches, and the first notches are matched with the second notches.

In one embodiment, the friction plate is coaxially arranged with the armature, the top surface of the friction plate is higher than the top surface of the tray, and the side surface of the friction plate is flush with the side surface of the tray.

In one embodiment, the tray is an interference fit with the spindle.

The application also provides a robot comprising an electromagnetic brake according to any of claims 1-9, which electromagnetic brake is fitted at the robot joint.

The electromagnetic brake and the robot provided by the application have at least the following beneficial effects: the friction plate and the tray are combined into a whole to form the brake disc, the brake disc is directly fixedly connected on the main shaft, friction noise and dust are prevented from being generated due to the fact that the brake disc moves along the main shaft, meanwhile, the friction surface of the brake during braking is adjusted to be a single surface of the friction plate, and the dust amount generated during friction is further reduced.

In addition, the bearing is directly arranged in the brake body, so that the space height occupied by additionally arranging the bearing can be saved.

Drawings

FIG. 1 is a cross-sectional view of an electromagnetic brake in one embodiment;

FIG. 2 is an enlarged view of a portion of FIG. 1 of the electromagnetic brake in one embodiment, FIG. 2 illustrating the exterior mating relationship of the brake body, armature and brake disc;

fig. 3 is a schematic view of the structure of a brake body and an armature of an electromagnetic brake in an embodiment.

Reference numerals illustrate:

10. An electromagnetic brake; 100. a main shaft; 110. a first step; 120. a second step; 200. a brake body; 201. a connector lug; 202. a first recess; 203. a threaded through hole; 204. a mounting groove; 210. an armature; 211. a second notch; 220. a bearing; 230. a guide post; 231. a sliding body; 232. a limiting body; 240. a bolt; 300. a brake disc; 310. a tray; 320. friction plate.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Referring to fig. 1 and 3, an electromagnetic brake 10 has the advantages of simple and compact structure, low heat generation, low noise, light weight, easy installation, wide adaptability, sensitive action, reliable braking and high speed. The electromagnetic brake 10 includes: spindle 100, brake body 200, and brake disc 300. The brake body 200 is sleeved on the main shaft 100, and the bottom of the brake body 200 is connected with the armature 210; the brake disc 300 includes a tray 310 and a friction plate 320, the tray 310 is fixedly connected to the spindle 100, the friction plate 320 is fixedly connected to the tray 310, and the friction plate 320 partially exposes the top of the tray 310; the brake body 200 drives the armature 210 to approach or depart from the friction plate 320, and when the brake body 200 is powered off, the armature 210 is pushed out, and the armature 210 and the friction plate 320 are in single-side abutting braking. The friction plate 320 and the tray 310 are integrally arranged to form the brake disc 300, so that the thickness of the whole electromagnetic brake 10 is reduced, the difficult problem of installation caused by the structural size is avoided, and the applicability of the electromagnetic brake 10 is improved. In addition, the friction plate 320 in the application is arranged in a single-sided friction mode, compared with a conventional friction mode, the friction plate has the advantage of low noise, greatly improves the working environment of the electromagnetic brake 10 and a matched device thereof, reduces the harm of industrial noise to the body of staff, and simultaneously, the single-sided arrangement mode of the friction plate 320 reduces the dust amount generated during friction, thereby being beneficial to environmental protection. The electromagnetic brake 10 is in power-off braking, the overall axial size of the electromagnetic brake 10 is small, the electromagnetic brake is lighter and thinner, the electromagnetic brake is compact in structure and convenient to install, and the braking torque is large, so that the braking requirement can be met to a great extent.

In one embodiment, the spindle 100 is a transmission output shaft of a micro motor, a servo motor and a stepping motor which are matched with the joint of the robot, the spindle 100 is in a ladder shape, the spindle 100 comprises a first step 110 and a second step 120, a bearing 220 is sleeved on the first step 110, and a brake disc 300 is fixedly connected on the second step 120.

In another embodiment, the spindle 100 is in an optical axis shape, a stepped shaft sleeve (not shown in the figure) is fixedly connected to the spindle 100 through a flat key or a spline, the shaft sleeve is fixedly connected to the bearing 220 and the brake disc 300 respectively, and after the shaft sleeve is added, the load borne by the spindle 100 is dispersed by the passage of the shaft sleeve part, so that the load of the spindle 100 is reduced, and the service life of the spindle 100 is prolonged.

In one embodiment, the brake body 200 and the armature 210 are disk-shaped or ring-shaped, with the brake body 200 having a central bore with a mounting slot 204 therein for mounting a bearing 220. The brake body 200 is provided with a connector lug 201, and the connector lug 201 is electrically connected with an external circuit and supplies power to the integral electromagnetic brake 10. An exciting coil (not shown in the figure) is arranged in the brake body 200, the exciting coil can attract or disengage the armature 210 through an exciting principle, so that the armature 210 can be far away from or close to the friction plate 320, a rated direct-current voltage of the exciting coil can be designed to be a special voltage according to user requirements in specific implementation, actuation force is ensured to be controlled, the exciting coil can attract the armature 210 tightly when the electromagnetic brake 10 is used, and preferably, the exciting coil winding uses an F-level heat-resistant grade copper wire, so that stability of working temperature is ensured.

In one embodiment, the armature 210 is made of electrical pure iron DT4, which ensures electromagnetic performance, and the armature 210 has a mesa structure with a central hole, through which the spindle 100 penetrates when installed.

In one embodiment, the brake body 200 has a plurality of guide posts 230 in an annular array, the guide posts 230 are made of low-carbon 10-grade steel, toughness and rigidity are guaranteed, the guide posts 230 are fixedly connected with the brake body 200, the armature 210 is slidably connected with the guide posts 230, specifically, the guide posts 230 are provided with threaded connection holes along the central axis, the positions of the brake body 200 corresponding to the threaded connection holes are provided with threaded through holes 203, the threaded connection holes are matched with the threaded through holes 203, the threaded connection holes are internally and threadedly connected with the threaded through holes 203 through the matched bolts 240, so that the guide posts 230 are fixedly connected with the brake body 200, and other fixing modes capable of meeting the functions in the prior art can be applied to the embodiment of the application, and the application is not limited. In addition, a stop washer or a winding of a green tape may be used for the anti-loosening treatment during the fastening of the bolts 240. Further, the guide post 230 includes a sliding body 231 fixedly connected to the brake body 200 and a limiting body 232 integrally formed at the top of the sliding body 231, the sliding body 231 is slidably connected to the armature 210, the sliding body 231 is sleeved with an elastic member (not shown in the figure), the elastic member is respectively abutted to the bottom of the brake body 200 and the top of the armature 210, and the elastic member is specifically a spring, which is a cylindrical spring with two ends of a carbon spring steel wire and is ground tightly. The electromagnetic brake 10 adopts a spring device to form braking torque, when the brake body 200 is powered off, the spring presses the armature 210 to force the friction plate 320 and the armature 210 to generate friction torque, so that the main shaft 100 can rapidly brake and stop rotating, the spring resetting time is the response time of the brake, the applying force of the spring is determined, and specific performance parameters and dimensions of the spring can be selected according to specific situations.

In another embodiment, both ends of the elastic member may be directly connected to the end surface of the actuator body 200 and the top end surface of the armature 210, and the arrangement position of the elastic member is not limited herein.

Referring to fig. 2, the outer diameter of the limiting body 232 is greater than the outer diameter of the guide post 230, the limiting body 232 is used to limit the axial sliding travel of the armature 210, so as to avoid the excessive travel of the armature 210, even beyond the normal design value, if the travel length of the armature 210 is increased above the normal value, the attractive force may be greatly reduced, thereby affecting the normal operation of the matching device, or causing adverse effects such as braking delay, etc., when the sliding travel is adjusted by the sliding body 231, it is required to ensure that the clearance between the armature 210 and the friction plate 320 is controlled within twenty percent of the specified value after the armature 210 is attracted to the brake body 200. Defining the bottom surface of the brake body 200 in fig. 2 as the base surface B, the plane height of the limiting body 232 is the distance H4 from the lowest end surface of the limiting body 232 to the base surface B, the plane height of the friction plate 320 is the distance H3 from the top end surface of the friction plate 320 to the base surface B, the plane height H4 of the limiting body 232 is greater than or equal to the plane height H3 of the friction plate 320, when the friction plate 320 rubs to a safe thickness, the limiting body 232 can prevent the armature 210 from further descending, the friction damage between the tray 310 and the friction plate 320 is avoided, in addition, the specific length of the sliding body 231 is determined by the thickness of the unused armature 210, the length H1 of the sliding body 231 is greater than the thickness H2 of the armature 210, but the larger part of the length is not too large, the sliding stroke of the armature 210 is avoided being influenced, and the arrangement mode can separate the armature 210 from the friction plate under the condition that the electromagnetic brake 10 does not need to brake, the rotation speed of the main shaft 100 is prevented from descending, and the deceleration phenomenon of a robot in normal use is avoided.

In another embodiment, a limit pin (not shown) may be used instead of the guide post 230, the limit pin is screwed in the threaded through hole 203, the armature 210 is slidably connected to a portion of the limit pin that is not screwed into the threaded through hole 203, and the sliding stroke of the armature 210 is adjusted by the depth of the limit pin screwed into the threaded through hole 203, so that other manners of performing the above-mentioned sliding guiding and limiting functions on the armature 210 in the prior art may be applied to embodiments of the present application, which are not limited herein.

In one embodiment, the outer periphery of the brake body 200 is provided with a plurality of first notches 202, the outer periphery of the armature 210 is provided with a plurality of second notches 211, the first notches 202 and the second notches 211 are matched, after the brake body 200 and the armature 210 are connected, the first notches 202 and the second notches 211 correspond to each other, when the brake body 200 is installed at a station, the first notches 202 and the second notches 211 can be used for positioning and installing the size, so that the convenience of installing the brake body 200 is improved, meanwhile, the number of the first notches 202 and the second notches 211 is multiple, under the condition that the brake body 200 and the armature 210 can bear force stably, the material loss is reduced, the production cost is reduced, and in addition, the working quality of the brake body 200 and the armature 210 is lower, and the design specification of light weight products is met.

In one embodiment, the brake further comprises a bearing 220, the bearing 220 is respectively matched with the main shaft 100 and the brake body 200, an inner ring of the bearing 220 is sleeved on the main shaft 100, an outer ring of the bearing 220 is fixedly connected in a mounting groove 204 in the brake body 200, and the bearing 220 is directly mounted in the brake body 200, so that the space height occupied by additionally mounting the bearing 220 can be saved. Since the electromagnetic brake 10 is applied to the joint of the robot, the bearing 220 can be a rolling bearing with strong axial bearing capacity and high rotation speed to meet the operation requirement of the robot. The bearing 220 can play a simple and accurate centering role when being installed, and particularly, the nominal size of the outer diameter of the bearing 220 is matched with the size of the installation groove 204 in the brake body 200, so that the concentricity of the brake body 200 is ensured, eccentric rotation of the brake body 200 during operation is prevented, and the bearing 220 is prevented from being damaged due to uneven radial stress. Preferably, when designing the brake body 200, a lightweight processing method is adopted as much as possible, so that the working quality of the brake body 200 is ensured not to cause overload of the bearing 220 in the axial direction.

In one embodiment, the friction plate 320 and the tray 310 are disk-shaped or ring-shaped, and the friction plate 320 and the tray 310 are also provided with a center hole, and the spindle 100 penetrates the center holes of the friction plate 320 and the tray 310. The interference fit of the tray 310 and the spindle 100 ensures the reliability of the integral connection of the tray 310, and simultaneously prevents friction noise and dust from being generated due to the integral movement of the brake disc 300 along the spindle 100. When the brake disc 300 is arranged, the tray 310 and the friction plate 320 can be integrally formed, so that the production and the assembly are convenient, and in addition, the tray 310 and the friction plate 320 can be fixedly connected together through countersunk pins or countersunk rivets. When the friction plate 320 is specifically arranged, the diameter of the friction plate 320 can be made as large as possible so as to obtain a better friction effect; for example, the friction plate 320 is entirely disposed on the top of the tray 310. Preferably, the friction plate 320 and the tray 310 may be provided with heat dissipation holes, especially when the friction plate 320 is large in size, the surface of the friction plate 320 will quickly heat up when the friction plate 320 contacts the armature 210 for braking, the temperature will increase with the increase of the braking time, and the hot air formed by braking will be discharged with the heat dissipation holes, thereby improving the heat dissipation efficiency and the braking efficiency at the robot joint.

In one embodiment, the friction plate 320 is disposed coaxially with the armature 210, so as to ensure that the contact area is maximized when the armature 210 contacts the friction plate 320 for braking, thereby increasing the braking effect. The tray 310 adopts electrical pure iron DT4 to ensure electromagnetic performance. The top surface of the friction plate 320 is higher than the top surface of the tray 310, so that friction braking between the armature 210 and the friction plate 320 is guaranteed when the armature 210 descends, and the tray 310 is prevented from being damaged due to dry friction between the armature 210 and the tray 310, and preferably, a wear warning mechanism can be arranged at the friction plate 320 or the tray 310, for example, the wear warning mechanism is arranged through the real-time thickness of the friction plate 320 or the tray 310, excessive wear of the friction plate 320 is prevented, and when the friction plate 320 is worn to a working safety thickness, workers are prompted to replace the friction plate 320. The side of the friction plate 320 is flush with the side of the tray 310, so that the integrity of the friction plate 320 and the tray 310 is ensured, the working stability is better, and the stress condition is more uniform.

In one embodiment, the friction plate 320 is made of a wear-resistant material, the friction material of the friction plate 320 may directly affect the whole braking process, the friction material should have a high and stable friction coefficient and good wear resistance, the friction material is classified into a metal friction material and a nonmetal friction material, the metal friction material may be cast iron, steel, bronze, powder metallurgy friction material, etc., and the specific selection of the friction material needs to be performed according to the working temperature and the temperature rising speed of the electromagnetic brake 10. Preferably, the friction plate 320 is made of a non-asbestos semi-metal friction material, which has low noise, high friction coefficient, low wear rate and environmental protection, and improves the service life of the brake. In addition, the friction material coefficient of the friction surface of the friction plate 320 is set to be about 0.4, and on the premise that the friction plate 320 can brake normally, the abrasion-resistant material is adopted to reduce the flying of friction dust of the friction plate 320 and improve the cleanliness of the operation.

Working principle: when the robot matched with the electromagnetic brake 10 is in a working state, the electromagnetic brake 10 is in a silent state as a whole, in the state, the brake body 200 is electrified, so that an exciting coil in the brake body 200 is attracted to the armature 210, at the moment, the spring is compressed, the armature 210 overcomes the elastic force of the spring, the top surface of the armature 210 is mutually abutted with the bottom surface of the brake body 200, and a working gap is reserved between the armature 210 and the friction plate 320, so that the main shaft 100 can normally operate; when the robot matched with the electromagnetic brake 10 is in a state to be stopped, the electromagnetic brake 10 is in a braking state as a whole, in this state, the brake body 200 is powered off, the spring is in a reset state and pushes the armature 210 away from the brake body 200, the armature 210 descends along the sliding part of the sliding column, the top surface of the armature 210 is separated from the bottom surface of the brake body 200, the armature 210 is in contact with the friction plate 320 for braking until the main shaft 100 is completely stopped, and the protection of the robot joint is realized. Thus, the whole main shaft 100 braking process is completed. When the electromagnetic brake 10 enters the next working cycle, after the exciting coil is electrified, the armature 210 is attracted to the brake body 200 under the action of electromagnetic force, so that the friction plate 320 is released, the purpose of releasing braking is achieved, normal operation of the matching device is facilitated, and meanwhile, preparation is made for the next braking.

It should be noted that, when the electromagnetic brake 10 is installed and used, components that interfere with use, such as moisture and oil, should be avoided as much as possible in the working environment, and in particular, if the friction part cannot be adhered with substances, such as moisture and oil, the friction torque force is avoided from being greatly lost, and the sensitivity of braking is reduced, it is preferable that a moisture-proof or waterproof cover body is covered outside the whole electromagnetic brake 10 to improve the internal stability of the electromagnetic brake 10 during operation, and the cover body may be a stamped or injection molded shell structure, or a cast molded shell structure, for example.

The application also provides a robot, which comprises the electromagnetic brake 10, wherein the robot is provided with a multi-stage robot joint, the electromagnetic brake 10 is arranged in the robot joint, a driving piece for driving the joint to move is arranged at the robot joint, the driving piece is provided with a micro motor, a servo motor, a stepping motor and the like, and a transmission output shaft of the driving piece can extend into the electromagnetic brake 10 and is connected with a brake disc 300 and a bearing 220 of the electromagnetic brake 10.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. An electromagnetic brake, comprising:

A main shaft;

The brake body is sleeved on the main shaft and is provided with an armature, the brake body is provided with a plurality of guide posts in an annular array, the guide posts are fixedly connected with the brake body, the armature is in sliding connection with the guide posts, the guide posts comprise a sliding body fixedly connected with the brake body and a limiting body integrally formed at the top of the sliding body, the sliding body is in sliding connection with the armature, the peripheral diameter of the limiting body is larger than that of the sliding body, the limiting body is used for limiting the axial sliding stroke of the armature, the length of the sliding body is larger than that of the armature, and the plane height of the limiting body is larger than or equal to that of a friction plate; and

2. The electromagnetic brake as recited in claim 1, wherein the slider body is sleeved with an elastic member that abuts the brake body and the armature, respectively.

3. The electromagnetic brake of claim 1, further comprising a bearing, wherein an inner ring of the bearing is sleeved on the main shaft, and an outer ring of the bearing is fixedly connected inside the brake body.

4. The electromagnetic brake of claim 1, wherein the brake body is provided with a connector lug that is electrically connected to an external circuit.

5. The electromagnetic brake of claim 1, wherein the outer periphery of the brake body is provided with a plurality of first notches and the outer periphery of the armature is provided with a plurality of second notches, the first notches being adapted to the second notches.

6. The electromagnetic brake of claim 1, wherein the friction plate is disposed coaxially with the armature, a top surface of the friction plate is higher than a top surface of the tray, and a side surface of the friction plate is flush with a side surface of the tray.

7. The electromagnetic brake of claim 1, wherein the tray is an interference fit with the spindle.

8. A robot comprising an electromagnetic brake according to any of claims 1-7, said electromagnetic brake being fitted at a robot joint.