WO2023246635A1

WO2023246635A1 - Centrifugal brake and lifting electric cylinder

Info

Publication number: WO2023246635A1
Application number: PCT/CN2023/100664
Authority: WO
Inventors: 胡国享; 李永成; 汤成建; 叶菁
Original assignee: 江苏恒立液压股份有限公司
Priority date: 2022-06-22
Filing date: 2023-06-16
Publication date: 2023-12-28
Also published as: CN217633566U

Abstract

The present application relates to the field of electric cylinders, and in particular to a centrifugal brake and a lifting electric cylinder. The centrifugal brake comprises: a rotor, wherein the rotor can be assembled in a rotating mode; brake blocks, wherein at least two brake blocks are provided, and the at least two brake blocks can be radially and slidably assembled on the periphery of the rotor; and annular elastic members, wherein the annular elastic members are embedded in the same axial end surface of all the brake blocks, and under the action of the annular elastic members, the brake blocks are pressed inwardly against the periphery of the rotor. The number of annular elastic members is two, and the two annular elastic members are respectively embedded in two axial end surfaces of all the brake blocks. A mounting groove is formed in the axial end surface of each brake block for the annular elastic member to embed, and the mounting groove has an opening that is configured to be gradually narrowed. The technical problems in the prior art of small braking area and low braking efficiency caused by elastic members of a centrifugal brake occupying circumferential space are solved.

Description

A centrifugal brake and electric lifting cylinder

Technical field

This application relates to the field of electric cylinders, specifically a centrifugal brake and a lifting electric cylinder.

Background technique

Electric cylinders are products designed for continuous motion, low to high loads (usually high speeds), and can be used multiple times during their service life. These products have extremely high positioning accuracy and controllability, and can be used under load conditions. Achieve precise motion control from kilogram to 50 tons. In scissor aerial work platforms, electric cylinders are often used to provide lifting driving force for the scissor structure.

For example, the document with application number CN202122404602.1 discloses a scissor-type aerial work platform, and specifically discloses: the scissor-type aerial work platform includes a chassis, a scissor-type lifting component and a lifting limit mechanism; the scissor-type aerial work platform The scissor lift assembly includes a scissor lift mechanism and an electric cylinder installed in the scissor lift mechanism; the electric cylinder installed in the scissor lift mechanism is used to drive the scissor lift mechanism to lift, in other words, This scissor-type aerial work platform uses electric cylinder-driven lifting instead of hydraulic cylinder-driven lifting. In this way, there is no need to install a hydraulic oil tank for storing hydraulic oil and complex hydraulic oil circuits. There is no oil leakage, and it is easy to maintain. It can be used during operations. Used in places with high environmental requirements.

The above-mentioned documents disclose the use of electric cylinders instead of hydraulic cylinders to drive the scissor-type lifting mechanism to lift and lower, which can be used in places with high operating environment requirements. However, there is no speed limiting device on the electric cylinder. This electric cylinder is used for scissor-type high-altitude operations. On the vehicle, when the aerial work vehicle is retracted in an emergency without power or the motor electromagnetic brake fails, the aerial work platform will accelerate back down under the action of its own weight. If the speed of the falling process is uncontrollable, it will have a negative impact on the lives of aerial work workers. There is a certain threat, so the speed of the electric cylinder must be controlled within a certain range.

In order to solve the above problems, the document with application number CN202121346841.X discloses an electric cylinder for a scissor-type aerial work vehicle, and specifically discloses: an electric cylinder for a scissor-type aerial work vehicle, including an For a forward and reverse rotating motor, the output shaft of the motor is connected to the primary gear of the multi-stage gear reduction box, and the final gear of the multi-stage gear reduction box is power transmission connected to the screw assembly in the cylinder. There is also a screw assembly in the cylinder. The piston structure component is connected to the screw assembly. The speed limiter includes a box body with an overspeed clutch. The first gear of the multi-stage gear reduction box is connected to a transmission shaft, and the other end of the transmission shaft is fixedly connected to the overspeed clutch. , the screw assembly stalls and decreases, the power passes through the multi-stage gear reduction box and accelerates in multiple stages, so that the first gear increases the speed and drives the transmission shaft and motor to accelerate and reverse. The overspeed clutch brakes the transmission shaft to limit the speed of the first gear, thereby Make the motor reverse at a constant speed; the overspeed clutch includes a shaft sleeve, and the shaft sleeve fixed sleeve is set on the transmission shaft. Mounting brackets are symmetrically arranged at both ends of the shaft sleeve. The outside of the mounting bracket is equipped with friction plates that fit with the box body. Two mounting brackets are installed. The left and right sides of the frame are connected by springs. There is also a counterweight block between the mounting frame and the shaft sleeve. A sliding pad is installed between the left and right sides of the counterweight block and the shaft sleeve.

The electric cylinder in the above document can limit the speed by braking the transmission shaft through the overspeed clutch, but its overspeed clutch adopts the form of a double-plate centrifugal block, and the spring is located between the two centrifugal blocks in the circumferential direction, occupying the circumferential space. The braking area of the centrifugal block is small, and the centrifugal brake assembly has many components, making the assembly complex and costly.

Contents of the invention

In order to solve the technical problems in the prior art that the elastic parts of centrifugal brakes occupy circumferential space, resulting in small braking area and low braking efficiency, this application provides a centrifugal brake and lifting electric cylinder, which solves the above technical problems. The technical solution of this application is as follows:

A centrifugal brake consisting of:

A rotor that can be assembled as it rotates;

Brake blocks, there are at least two brake blocks, and at least two brake blocks are radially slidably assembled on the outer circumference of the rotor;

An annular elastic member is embedded in the same axial end surface of all brake blocks. Under the action of the annular elastic member, the brake blocks are pressed inwardly against the outer periphery of the rotor.

In the centrifugal brake of the present application, by setting the annular elastic member embedded in the axial end surface of the brake pad, the annular elastic member does not need to occupy the circumferential space, and the extension length of the brake pad in the circumferential direction can be increased, thereby increasing the The braking area is large and the braking efficiency is high; in addition, the annular elastic part is embedded in the axial end face of the brake block, so the annular elastic part does not need to be connected and installed, which is convenient to install, and the annular elastic part does not occupy the axial space. Conducive to compact structure and miniaturization.

According to an embodiment of the present application, there are two annular elastic members, and the two annular elastic members are respectively embedded on the two axial end surfaces of all brake pads.

According to an embodiment of the present application, a mounting groove is formed on the axial end surface of the brake pad to embed the annular elastic member, and the opening of the mounting groove is configured to be constricted.

According to one embodiment of the present application, a sliding portion extends from the inner circumference of the brake pad, and at least two slide grooves are provided on the outer circumference of the rotor. The sliding portion of the brake pad can extend into the sliding groove. Sliding fit in the groove.

According to an embodiment of the present application, the brake block includes a weight block and a friction plate, so The counterweight block is in sliding fit with the rotor, and the friction plate is assembled on the outer peripheral surface of the counterweight block.

According to an embodiment of the present application, there are three brake blocks, and the three brake blocks can be assembled into a ring shape.

An electric lifting cylinder includes:

motor;

Telescopic cylinder, the telescopic cylinder includes a cylinder barrel and a piston structure, and the piston structure is slidably assembled in the cylinder barrel;

A screw assembly, the screw assembly extends into the piston structure, the motor drives the screw assembly to move, and the piston structure moves along the cylinder barrel driven by the screw assembly;

A centrifugal brake that limits the rotational speed of the motor.

According to one embodiment of the present application, the motor drives the screw assembly to work through a gearbox. The gearbox includes an outer box, and a primary gear and a final gear are assembled in the outer box. The primary gear The output shaft of the motor is connected with the first-stage gear through a plurality of intermediate gears, and the final gear is connected with the screw assembly with rotation.

According to an embodiment of the present application, a gear shaft extends from the first-stage gear, and the rotor of the centrifugal brake is engaged with the gear shaft in rotation.

According to an embodiment of the present application, the centrifugal brake is assembled in the outer box, and a mating surface that matches the centrifugal brake is formed in the outer box.

Based on the above technical solution, the technical effects that this application can achieve are:

1. In the centrifugal brake of this application, by setting the annular elastic member embedded in the axial end surface of the brake block, the annular elastic member does not need to occupy the circumferential space, and the extension length of the brake block in the circumferential direction can be increased, thereby enabling The braking area is increased and the braking efficiency is high; in addition, the annular elastic part is embedded on the axial end face of the brake block, so the annular elastic part does not need to be connected and installed, which is convenient for installation, and the annular elastic part does not occupy the axial direction. space, which is conducive to compact structure and miniaturization; further set up two annular elastic members, and the two annular elastic members are respectively embedded on the two axial end faces of all brake blocks to ensure that all brake blocks are aligned in the axial direction. force balance;

2. The centrifugal brake of this application is equipped with a mounting groove on the axial end face of the brake block to assemble the annular elastic member. The annular elastic member can be embedded in the brake block without axially protruding from the brake block. The block causes the volume to increase; further, the opening of the installation groove is configured to be constricted, which can prevent the annular elastic member from escaping from the installation groove during high-speed rotation and ensure the stability of the overall structure of the centrifugal brake;

3. In the centrifugal brake of this application, a sliding part is formed on the brake block, and the sliding part slides with the chute on the rotor to ensure that the rotor and the brake block can rotate together, and the brake block can slide radially relative to the rotor. ;

4. When the lifting electric cylinder of this application uses a centrifugal brake to limit the motor speed, when the rotor speed is low, the centrifugal force < the pulling force of the annular elastic member, and the centrifugal brake rotates synchronously with the output shaft of the motor; the centrifugal force > the pulling force of the annular elastic member , the centrifugal force generated by the brake block causes the brake block to contact the mating surface in the outer box to generate a braking torque. When the generated braking torque is equal to the reverse torque generated by gravity, the equilibrium speed is reached;

5. The lifting electric cylinder of this application is equipped with a motor to drive the screw assembly through a gear box. The outer box of the gear box is equipped with gears for transmission, which can achieve multi-level acceleration; in addition, the separation is The central brake is also installed in the outer box and cooperates with the gear shaft of the first-level gear to limit the speed of the motor. At the same time, there is no need to set up an additional brake housing, which reduces costs; and the brake does not need to protrude from the outer box. , to facilitate the assembly of the overall structure.

Description of the drawings

Figure 1 is a schematic structural diagram of the centrifugal brake of the present application;

Figure 2 is an exploded view of the centrifugal brake;

Figure 3 is a schematic structural diagram of the rotor;

Figure 4 is a schematic structural diagram of the brake pad;

Figure 5 is a side view of the brake pad;

Figure 6 is a schematic structural diagram of the counterweight block;

Figure 7 is a schematic structural diagram of the electric cylinder of the present application;

Figure 8 is an enlarged view of part A of Figure 7;

Figure 9 is an enlarged view of part B of Figure 7;

In the picture: 1-rotor; 11-assembly hole; 12-slide; 13-stop; 14-positioning step; 2-brake block; 21-counterweight; 211-installation part; 2111-installation slot; 212 -Sliding part; 22-friction plate; 3-annular elastic member; 4-motor; 5-telescopic cylinder; 51-cylinder; 52-piston structure; 521-piston; 522-piston rod; 6-screw assembly; 61 -Screw rod; 611-bearing sleeve; 612-bearing; 613-inner support; 62-nut; 7-mounting barrel; 8-gear box; 81-outer box; 82-first-level gear; 821-gear shaft; 83-Final gear; 84-Intermediate gear; 9-Electromagnetic brake; 91-Manual release switch; 10-Rod head connector.

Detailed ways

The technical methods in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. The application is clearly and completely described. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application or its application or uses. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular forms are also intended to include the plural forms unless the context clearly indicates otherwise. Furthermore, it will be understood that when the terms "comprises" and/or "includes" are used in this specification, they indicate There are features, steps, operations, means, components and/or combinations thereof.

The relative arrangement of components and steps, numerical expressions, and numerical values set forth in these examples do not limit the scope of the application unless specifically stated otherwise. At the same time, it should be understood that, for convenience of description, the dimensions of various parts shown in the drawings are not drawn according to actual proportional relationships. Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods and devices should be considered a part of the specification. In all examples shown and discussed herein, any specific values are to be construed as illustrative only and not as limiting. Accordingly, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters refer to similar items in the following figures, so that once an item is defined in one figure, it does not need further discussion in subsequent figures.

In the description of this application, it should be understood that the directions indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" etc. The positions or positional relationships are generally based on the orientations or positional relationships shown in the drawings, which are only for the convenience of describing the present application and simplifying the description. Without explanation to the contrary, these positional words do not indicate or imply the referred devices or devices. Components must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be construed as limiting the scope of the present application; the orientation words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

For the convenience of description, spatially relative terms can be used here, such as "on...", "on...", "on the upper surface of...", "above", etc., to describe what is shown in the figure. The spatial relationship between one device or feature and other devices or features. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a feature in the figure is turned over, then one feature described as "above" or "above" other features or features would then be oriented "below" or "below" the other features or features. under other devices or structures". Thus, the exemplary term "over" may include both orientations "above" and "below." The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In addition, it should be noted that the use of words such as "first" and "second" to define parts is only to facilitate the distinction between corresponding parts. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood. To limit the scope of protection of this application.

As shown in Figures 1-9, this embodiment provides a centrifugal brake, including a rotor 1 and a brake block 2. The rotor 1 can be assembled with rotation, and the brake block 2 is radially slidably assembled on the rotor 1. The annular elastic member 3 provides restoring force for all brake pads 2. When the rotor speed is low, The centrifugal force on the brake pad 2 is less than the tensile force of the annular elastic member 3. The brake pad 2 is pressed against the rotor 1 under the action of the annular elastic member 3; when the rotation speed reaches a certain value, the centrifugal force on the brake pad 2 is greater than Due to the tensile force of the annular elastic member 3, the brake pad 2 overcomes the tensile force of the annular elastic member 3 and slides radially away from the rotor 1. The outer peripheral surface of the brake pad 2 contacts the mating surface to generate braking torque.

The rotor 1 is cylindrical, and an assembly hole 11 is formed in the middle of the rotor 1. In order to facilitate the assembly of the rotor 1 as it rotates, a flat keyway can be extended on one side of the assembly hole 11. In this way, when the rotor 1 is assembled on the braked shaft When it is on, the rotor 1 can be assembled on the braked shaft with the rotation through the cooperation of the flat key and the flat keyway.

In order to slide and assemble the brake block 2, concave slide grooves 12 are formed on the outer peripheral surface of the rotor 1. There are at least two slide grooves 12. The at least two slide grooves 12 are evenly distributed on the outer peripheral surface of the rotor 1. Adjacent slide grooves 12 are formed on the outer peripheral surface of the rotor 1. There are stops 13 between the grooves 12 to act as a partition. The chute 12 can radially slide and cooperate with the brake block 2, and the rotor 1 can drive the brake block 2 to rotate through the chute 12. The shape of the chute 12 is not limited. In this embodiment, the chute 12 is provided as an installation groove, and there are three chute 12 .

As a preferred technical solution of this embodiment, in order to facilitate the positioning of the rotor 1 when it is assembled on the braked shaft, a positioning step 14 is provided extending from one axial end of the rotor 1 .

The brake blocks 2 are slidably assembled on the rotor 1. The brake blocks 2 can be in the shape of an arc-shaped block as a whole. There are at least two brake blocks 2. The at least two brake blocks 2 are slidably assembled on the chute 12 in one-to-one correspondence. , all the brake blocks 2 can basically form a ring shape when spliced together. The brake block 2 includes a counterweight block 21 and a friction plate 22. The counterweight block 21 is an arc-shaped block, and the friction plate 22 is assembled on the outer peripheral surface of the counterweight block 21. Specifically, the counterweight block 21 includes a mounting part 211 and a sliding part along the radial direction. 212. The sliding part 212 is inserted into the chute 12 to realize the sliding assembly of the brake block 2 on the rotor 1; a mounting groove 2111 is formed on the axial end surface of the mounting part 211 to assemble the annular elastic member 3. The outer peripheral surface of the mounting part 211 The friction plate 22 is fixedly assembled on the upper part. In this embodiment, the number of brake blocks 2 is three, and the three brake blocks 2 can be assembled into a ring shape.

As a preferred technical solution of this embodiment, the axial thickness of the mounting part 211 is greater than the axial thickness of the sliding part 212, and both axial ends of the mounting part 211 protrude from the sliding part 212. In this way, when the sliding part 212 is slidably inserted into the chute, 12, under the action of the annular elastic member 3, the inner circumferential surface of the mounting portion 211 that is in contact with the sliding portion 212 can abut against the notch of the slot 12 to play a limiting role.

As a preferred technical solution of this embodiment, the mounting groove 2111 is arc-shaped. The mounting groove 2111 extends from one circumferential end of the mounting portion 211 to the other end. The mounting groove 2111 penetrates the axial end surface of the mounting portion 211 from the circumferential direction. Further preferably, the opening of the installation groove 2111 is configured to be constricted, that is, the radial width inside the installation groove 2111 is greater than the radial width at the groove opening. In this way, when assembling the annular elastic member 3, the annular elastic member 3 can be appropriately squeezed to Assemble the annular elastic member 3 into the installation groove 2111. During use, due to the shrinkage arrangement of the installation groove 2111, the annular elastic member 3 is not easy to come out of the installation groove 2111. The mounting grooves 2111 on the same axial end surface of all brake pads 2 are located in the same circumferential direction. Preferably, mounting grooves 2111 are provided on both axial ends of the mounting portion 211 of each brake pad 2, and the two mounting grooves 2111 on each brake pad 2 are located in the same circumferential direction.

The annular elastic member 3 is assembled in the installation groove 2111 of the brake block 2. The annular elastic member 3 can be embedded in the installation groove 2111 of all the brake blocks 2 on the same axial end face. The annular elastic member 3 will not be installed from the installation groove 2111. The groove 2111 protrudes axially. Compared with the adjacent ones in the prior art The brake pads 2 are connected and matched circumferentially by elastic members. The annular elastic member 3 in this embodiment is in the shape of a closed ring and adopts embedded assembly. There is no need to provide a connection structure, and the annular elastic member 3 does not need to occupy the adjacent brake pad 2. The circumferential space between them will not limit the braking area of the brake pad 2. The braking area of the brake pad 2 in this embodiment is increased and the braking efficiency is high.

As a preferred technical solution of this embodiment, there are two annular elastic members 3, and the two annular elastic members 3 are respectively assembled on both axial ends of all brake blocks 2 to ensure the axial balance of the overall structure of the centrifugal brake. .

This embodiment also provides an electric lifting cylinder, which includes a motor 4, a telescopic cylinder 5 and the aforementioned centrifugal brake. The motor 4 drives the telescopic cylinder 5 to perform telescopic movement by driving the screw assembly 6, and the centrifugal brake is used to limit the motor 4 of rotational speed.

The motor 4 is a motor that can rotate forward and reverse. The motor 4 drives the screw assembly 6 to move through the gearbox 8 . Specifically, the gearbox 8 includes an outer box 81. The outer box 81 is equipped with a primary gear 82 and a final gear 83. The primary gear 82 and the final gear 83 are driven and matched through a number of intermediate gears 84. 82 is connected with the output shaft of the motor 4 with the rotation, and the final gear 83 is connected with the screw assembly 6 with the rotation. In terms of specific assembly, the output shaft of the motor 4 can be set to extend into the outer box 81 to connect with the first-stage gear 82; one end of the screw rod 61 in the screw assembly 6 can extend into the outer box 81 and connect with the final gear 83. connect. Preferably, the motor 4, the screw assembly 6 and the telescopic cylinder 5 are assembled on the same side of the outer box 81.

As a preferred technical solution of this embodiment, an electromagnetic brake 9 with a manual release switch 91 is installed at the rear end of the motor 4. When the motor is powered off, pressing the manual release switch 91 causes the screw assembly 6 to stall and descend.

The telescopic cylinder 5 includes a cylinder tube 51 and a piston structure 52. The piston structure 52 is slidably assembled on In the cylinder 51, the piston structure 52 includes a piston 521 and a piston rod 522. The piston 521 is in sliding fit with the inner wall of the cylinder 51. The piston rod 522 is fixedly connected to the piston 521. There is a gap between the piston rod 522 and the inner wall of the cylinder 51. There is a gap.

As a preferred technical solution of this embodiment, the cylinder tube 51 of the telescopic cylinder 5 is a cylindrical body with both ends open. The bottom of the telescopic cylinder 5 is arranged close to the outer box 81 , and one end of the cylinder tube 51 close to the outer box 81 passes through The installation barrel 7 is fixedly connected to the outer box 81; the other end of the cylinder barrel 51 is provided with a limiter, the piston rod 522 extends from the other end of the cylinder barrel 51, and is connected with the rod head connector 10.

As a preferred technical solution of this embodiment, the piston structure 52 is a hollow structure to facilitate the assembly of the screw assembly 6 and ensure the driving effect of the screw assembly 6 on the piston structure 52 .

The screw assembly 6 includes a threaded screw 61 and a nut 62. The screw 61 is rotated and assembled. Driven by the final gear 83, the rotation of the screw 61 drives the nut 62 on it to perform linear reciprocating motion. The nut 62 drives the piston. The structure 52 makes linear reciprocating motion along the cylinder 51 .

During assembly, one end of the screw rod 61 that matches the final gear 83 is rotated and assembled on the installation barrel 7. Specifically, the screw rod 61 is tightened with a bearing sleeve 611, and the bearing sleeve 611 is rotated and assembled on the installation sleeve 7 through the bearing 612. on the inner wall. The other end of the screw rod 61 extends into the interior of the piston structure 62. The other end of the screw rod 61 is slidably matched with the inner wall of the piston rod 522 through the inner support 613. The screw rod 61 can rotate relative to the piston rod 522, and the piston rod 522 can rotate relative to the piston rod 522. The screw rod 61 moves linearly. Preferably, the bearing 612 may be, but is not limited to, a single row tapered roller bearing. The nut 62 is threadedly assembled on the screw rod 61 , and the nut 62 is fixedly connected to the piston 521 of the piston structure 52 .

The centrifugal brake is assembled in the outer box 81, and a cavity is separated inside the outer box 81 for assembly. The centrifugal brake limits the rotation speed of the motor 4 by acting on the gear shaft of the primary gear 82 . Specifically, the primary gear 82 is connected to the output shaft of the motor 4, the gear shaft 821 of the primary gear 82 extends into the cavity of the outer box 81, and the centrifugal brake is assembled on the gear shaft of the primary gear. During assembly, the assembly hole 11 of the rotor 1 is matched with the gear shaft 821 with a flat key. The end of the gear shaft 821 away from the primary gear 82 is rotationally supported on the wall of the outer box 81 through the bearing. The positioning boss 14 on the rotor 1 It rests on the bearing to position the centrifugal brake so that there is an axial gap between the brake block 2 and the inner wall of the outer box 81 so that the two will not come into contact to cause friction and thus affect the operation of the centrifugal brake.

The separated cavity of the outer box 81 has a mating surface, and the mating surface is in clearance fit with the outer circumferential surface of the centrifugal brake. When the rotor 1 rotates at a low speed, the centrifugal force < the tensile force of the annular elastic member, and the centrifugal brake rotates synchronously with the output shaft of the motor; When the centrifugal force is greater than the tensile force of the annular elastic member, the centrifugal force generated by the brake block 2 causes the brake block 2 to contact the mating surface in the outer box to generate a braking torque until the generated braking torque is equal to the reverse torque generated by gravity. That is, the equilibrium speed is reached.

The electric cylinder of this embodiment is applied to a scissor-type aerial work vehicle. When it rises, the motor 4 is powered on and runs at rated speed. The motor 4 passes through the gearbox 8 and drives the piston rod 522 of the piston structure 52 to rise until the external load (Aerial work vehicle) reaches the highest position. At this time, the motor 4 is powered off, and the electromagnetic brake 9 holds the rotor shaft of the motor 4 tightly to prevent the piston rod 522 from falling back. During this process, the centrifugal brake does not limit the speed.

When the scissor aerial work vehicle is withdrawn in an emergency or the motor fails, the manual release switch 91 of the electromagnetic brake 9 needs to be pulled, the electromagnetic brake 9 is opened, the platform begins to accelerate back down under the action of its own weight, and the screw rod 61 accelerates to rotate, driving the final stage Gear 83 rotates and passes through gear box 8 After the multi-stage acceleration of the gear inside, the first-stage gear 82 accelerates and rotates, driving the centrifugal brake to rotate synchronously. When the speed reaches the centrifugal brake speed limit value, that is, when the centrifugal force > the spring tension, reverse braking torque begins to be generated, and the piston rod of the electric cylinder The retrieval of 522 was blocked, eventually causing the scissor aerial work vehicle to descend at a constant speed.

The embodiments of the present application have been described in detail above in conjunction with the accompanying drawings. However, the present application is not limited to the above-mentioned embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, other modifications can be made without departing from the purpose of the present application. various changes.

Claims

A centrifugal brake is characterized by including:

Rotor (1), the rotor (1) can be assembled with rotation;

Brake blocks (2), there are at least two brake blocks (2), and at least two brake blocks (2) are radially slidably assembled on the outer circumference of the rotor (1);

Annular elastic member (3). The annular elastic member (3) is embedded in the same axial end surface of all brake blocks (2). Under the action of the annular elastic member (3), the brake block (2) Press inwardly on the outer circumference of the rotor (1).
A centrifugal brake according to claim 1, characterized in that there are two annular elastic members (3), and the two annular elastic members (3) are respectively embedded in all brake blocks (2). on both axial end faces.
A centrifugal brake according to any one of claims 1-2, characterized in that the axial end surface of the brake block (2) is provided with a mounting groove (2111) to embed the annular elastic member (2111). 3), the opening of the installation groove (2111) is configured with a constriction.
A centrifugal brake according to claim 1, characterized in that a sliding part (212) extends from the inner circumference of the brake block (2), and at least two sliding parts are provided on the outer circumference of the rotor (1). Groove (12), the sliding portion (212) of the brake block (2) can extend into the chute (12) for sliding fit.
A centrifugal brake according to claim 1, characterized in that the brake block (2) includes a counterweight block (21) and a friction plate (22), and the counterweight block (21) and the rotor (1) Sliding fit, the friction plate (22) is assembled on the outer peripheral surface of the counterweight block (21).
A centrifugal brake according to claim 1, characterized in that the brake There are three moving blocks (2), and the three braking blocks (2) can be assembled into a ring shape.
An electric lifting cylinder is characterized by including:

motor(4);

Telescopic cylinder (5). The telescopic cylinder (5) includes a cylinder barrel (51) and a piston structure (52). The piston structure (52) is slidably assembled in the cylinder barrel (51);

Screw assembly (6). The screw assembly (6) extends into the piston structure (52). The motor (4) drives the screw assembly (6) to move. The piston structure (52) Move along the cylinder (51) driven by the screw assembly (6);

The centrifugal brake according to any one of claims 1 to 6, which limits the rotation speed of the motor (4).
An electric lifting cylinder according to claim 7, characterized in that the motor (4) drives the screw assembly (6) to work through a gearbox (8), and the gearbox (8) includes an outer The outer box (81) is equipped with a first-stage gear (82) and a final-stage gear. Several intermediate gears are passed between the first-stage gear (82) and the last-stage gear (84). (83) Transmission coordination, the output shaft of the motor (4) is connected with the first-stage gear (82) with the rotation, and the last-stage gear (84) is connected with the screw assembly (6) with the rotation.
An electric lifting cylinder according to claim 8, characterized in that the first-stage gear (82) extends with a gear shaft (821), and the rotor (1) of the centrifugal brake rotates in conjunction with the gear. on axis (821).
An electric lifting cylinder according to any one of claims 8-9, characterized in that the centrifugal brake is installed in the outer box (81), and the outer box (81) A mating surface for mating with the centrifugal brake is formed inside.