Dynamic friction plates, wet hydraulic brakes and aerial work platforms

Abstract

The present application discloses a dynamic friction plate suitable for a wet hydraulic brake, which is generally in the shape of a disc and includes an intermediate layer and two annular friction layers. An axial hole is provided at the center of the intermediate layer for cooperating with the output shaft of the hydraulic brake. The two friction layers are respectively bonded to the two surfaces of the intermediate layer, and the inner diameters of the two friction layers are larger than the diameter of the axial hole, thereby leaving annular areas not occupied by the friction layers on the two surfaces of the intermediate layer. At least one oil stirring hole is provided in the annular area. The present application also discloses a wet hydraulic brake having the dynamic friction plate provided therein and an aerial work platform using the wet hydraulic brake. By adopting the technical solution of the present application, the dynamic friction plate can dissipate heat faster, facilitating the circulation of lubricating oil or hydraulic oil inside the wet hydraulic actuator, thereby increasing the service life of the dynamic friction plate.

Description

Technical Field

[0001] The present application relates to a dynamic friction plate, a wet hydraulic brake with the dynamic friction plate arranged inside, and an aerial work platform using the wet hydraulic brake. Background Art

[0002] A brake is a device that has the function of slowing down, stopping or keeping a moving part (or moving machinery) stopped.

[0003] like Figure 1 and Figure 2A As shown, one type of hydraulic brake 1 is a spring-braked normally closed, wet, disc-type hydraulic brake. This hydraulic brake 1 has a housing 11, a rear cover 12, and an output shaft 13. This hydraulic brake 1 also has a piston 19, a piston chamber, a spring 18, a clutch mechanism, etc. located inside the housing 11 and the rear cover 12. The clutch mechanism includes a plurality of static friction plates 20 and a plurality of dynamic friction plates 21. The outer periphery of the static friction plate 20 is fitted on the inner wall of the housing 11, and the static friction plate 20 can be made of steel, for example. The dynamic friction plate 21 is loosely fitted on the outer periphery of the output shaft 13 by, for example, a spline structure. In the axial direction of the output shaft 13, these friction plates 20 and 21 are alternately arranged and can be pressed or loosened against each other in the front-rear direction.

[0004] Specifically, the piston 19 can move back and forth under the action of the elastic force of the spring 18 and the hydraulic pressure in the piston chamber, so that the clutch mechanism engages or disengages, thereby selectively allowing the output shaft 13 to rotate or preventing the output shaft 13 from rotating. The output shaft 13 extends from the front of the housing 11 and is connected to other related components, such as the wheel hub or brake disc (not shown) of the aerial work platform / work vehicle, through a flat key 14 and a locking nut 15. The rear cover 12 is assembled behind the housing 11. The hydraulic brake 1 also has an oil port 16. The oil port 16 is connected to a hydraulic oil channel provided inside the hydraulic brake 1, and can be connected to an external hydraulic oil supply / discharge device to supply hydraulic oil to the inside of the hydraulic brake and discharge the hydraulic oil inside the hydraulic brake to the outside. It should be noted that Figure 1 and Figure 2A The oil port 16 shown in FIG. 1 has been temporarily sealed by the sealing plug 17, so that Figure 1 and Figure 2A The oil port 16 in the open state is not shown.

[0005] like Figure 2A and Figure 2BAs shown, when no hydraulic oil acts on the oil port 16, the piston 19, under the elastic force of the spring 18, presses the friction plates 20 and 21, and then the friction between the friction plates 20 and 21 generates a braking torque. When the hydraulic brake 1 needs to be released, the hydraulic oil is introduced into the oil port 16, and the piston 19, under the action of the hydraulic pressure, loosens the friction plates 20 and 21 pressed against each other, and the friction between the friction plates 20 and 21 disappears, thereby releasing the hydraulic brake 1.

[0006] In the braking process of the existing hydraulic brake of this type, a large amount of heat will be generated on the friction plate. Therefore, the heat dissipation effect of the existing friction plate is not good, and the service life is short.

[0007] Therefore, the key points to be considered in the design scheme of this application include: 1) how to dissipate heat from the friction plate faster to increase the service life of the friction plate; 2) how the new design scheme can achieve better heat dissipation while retaining all the performance of the existing friction plate. Summary of the invention

[0008] In order to solve the above technical problems and potential other technical problems, according to one aspect of the present application, a dynamic friction plate for a wet hydraulic brake suitable for an aerial work platform is provided. The dynamic friction plate is generally disc-shaped. The dynamic friction plate comprises: an intermediate layer, an axial hole is arranged at the center of the intermediate layer, and the axial hole is suitable for cooperating with the output shaft of the hydraulic brake; and two annular friction layers, the two annular friction layers are respectively engaged on the two surfaces of the intermediate layer, and the inner diameter of the two annular friction layers is larger than the diameter of the axial hole, so that annular areas not occupied by the friction layers are left on the two surfaces of the intermediate layer. At least one oil stirring hole is opened on the annular area.

[0009] The at least one oil stirring hole may be in the following shapes: a circle; or an ellipse, wherein the major axis of the ellipse extends along the radial direction of the dynamic friction plate, and the minor axis of the ellipse extends perpendicularly to the radial direction of the dynamic friction plate; or a rectangle, wherein the axis of symmetry of the rectangle along the length direction extends along the radial direction of the dynamic friction plate, and the axis of symmetry of the rectangle along the width direction extends perpendicularly to the radial direction of the dynamic friction plate; or an isosceles triangle, wherein the axis of symmetry of the isosceles triangle extends along the radial direction of the dynamic friction plate, and the vertex angle of the isosceles triangle is closer to the center of the dynamic friction plate than the base of the isosceles triangle; or an isosceles trapezoid, wherein the axis of symmetry of the isosceles trapezoid extends along the radial direction of the dynamic friction plate, and the shorter base of the isosceles trapezoid is closer to the center of the dynamic friction plate than the longer base of the isosceles trapezoid; or a fan ring, wherein the axis of symmetry of the fan ring extends along the radial direction of the dynamic friction plate, and the shorter arc of the fan ring is closer to the center of the dynamic friction plate than the longer arc of the fan ring.

[0010] The number of the oil stirring holes may be more than one, and the oil stirring holes are evenly spaced and rotationally symmetrically distributed on a circle with the center of the dynamic friction plate as the center.

[0011] Specifically, the intermediate layer may be made of steel, and the friction layer may be made of a friction material. For example, the friction material may be a copper-based material formed of copper powder, or a paper-based material formed of pulp.

[0012] A plurality of grooves may be provided on the surface of the friction layer. The grooves may extend along a straight line and form a cross. Optionally, some of the plurality of grooves extend along a logarithmic spiral extending in a clockwise direction, and other grooves extend along a logarithmic spiral extending in a counterclockwise direction, and the grooves form a cross. Optionally, the plurality of grooves are distributed in a concentric circle pattern. Optionally, the plurality of grooves are distributed radially, and the center of the radiation is the center of the friction plate. Optionally, some of the plurality of grooves are distributed in a concentric circle pattern, and other grooves are distributed radially, so that the grooves form a cross.

[0013] According to another aspect of the present application, a wet hydraulic brake suitable for an aerial work platform is provided. The wet hydraulic brake comprises: a housing, a rear cover installed at the rear of the housing, an output shaft penetrating the front of the housing, a piston, a spring and a clutch mechanism. The piston can move forward and backward along the axial direction of the output shaft under the action of the elastic force of the spring and the hydraulic pressure, so that the clutch mechanism is engaged or disengaged. The clutch mechanism comprises: a plurality of static friction plates, the outer periphery of which is fitted on the inner wall of the housing; and a plurality of dynamic friction plates as described above, the axial holes of which are fitted on the outer periphery of the output shaft through splines. The static friction plates and the dynamic friction plates are arranged alternately and can move in the axial direction of the output shaft, thereby pressing or releasing each other.

[0014] Specifically, lubricating oil or hydraulic oil is poured into the housing, and the lubricating oil or hydraulic oil can immerse at least a portion of the static friction plate and the dynamic friction plate.

[0015] According to another aspect of the present application, there is provided an aerial work platform, the aerial work platform having wheels, the wheels having brakes, and the brakes are wet hydraulic brakes as described above.

[0016] By adopting the above technical solution, the present application can achieve the following beneficial effects:

[0017] 1) The heat dissipation area of ​​the dynamic friction plate is increased, so that the dynamic friction plate can dissipate heat faster.

[0018] 2) Make the lubricating oil or hydraulic oil flow more smoothly inside the brake, ensure the friction plate is evenly lubricated, and speed up the injection of lubricating oil.

[0019] 3) Fully stir the oil gathered at the lower part of the hydraulic brake housing to reduce the oil temperature.

[0020] 4) Make the oil form a splash lubrication effect and increase the service life of the dynamic friction plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to facilitate readers to understand the technical solution of the present application, the present application is described in more detail below based on exemplary embodiments and in conjunction with the accompanying drawings. The same or similar reference numerals are used in the accompanying drawings to represent the same or similar components. It should be understood that the accompanying drawings are only schematic, and the sizes and proportions of the components in the accompanying drawings are not necessarily accurate.

[0022] Figure 1 is a schematic perspective view of a hydraulic brake according to an embodiment of the present application.

[0023] Figure 2A It is cut along the vertical center plane Figure 1 Cross-sectional view of the hydraulic brake in FIG.

[0024] Figure 2B yes Figure 2A A partial enlarged view of area B in FIG.

[0025] Figure 3A and Figure 3B They are Figure 2A A three-dimensional view and a front view of the dynamic friction plate in the hydraulic brake.

[0026] Figure 3C It is along Figure 3B A cross-sectional view of the dynamic friction plate taken along plane CC in FIG.

[0027] Figure 3D yes Figure 3C A partial enlarged view of area D in FIG.

[0028] Figure 4A , Figure 4B , Figure 4C , Figure 4D , Figure 4E , Figure 4F and Figure 4G They are respectively front views of dynamic friction plates according to other embodiments of the present application. DETAILED DESCRIPTION

[0029] Reference has been made to the “Background Technology” section of this specification. Figure 1 , Figure 2A and Figure 2BThe overall structure of a hydraulic brake 1 according to an embodiment of the present application is described. The applicant needs to particularly point out that the above content is both a description of the background technology of the present application and a part of the specific implementation method of the present application. The present application does not repeat this part here just for the purpose of simplicity.

[0030] Next, we will refer to FIG. 3A to FIG. 3D The configuration of the dynamic friction plate 21 in the hydraulic brake 1 will be described. Figure 3A and Figure 3B They are Figure 2A A stereoscopic view and a front view of the dynamic friction plate 21 in the hydraulic brake 1. Figure 3C It is along Figure 3B A cross-sectional view of the dynamic friction plate 21 taken along plane CC in FIG. Figure 3D yes Figure 3C A partial enlarged view of area D in FIG.

[0031] like Figure 3A , Figure 3B and Figure 3C As shown, the dynamic friction plate 21 is generally disc-shaped and includes an intermediate layer 22 and two annular friction layers 23. An axial hole is provided at the center of the intermediate layer 22. A spline groove is provided on the inner periphery of the axial hole and is suitable for forming a clearance fit with the spline on the output shaft 13 of the hydraulic brake 1.

[0032] The friction layer 23 is made of friction material. For example, the friction material is a copper-based material formed by copper powder, or a paper-based material formed by pulp. A plurality of grooves 24 are provided on the surface of the friction layer 23. These grooves 24 extend along a straight line and form a cross.

[0033] like Figure 3C and Figure 3D As shown, two annular friction layers 23 are respectively bonded on two surfaces of the middle layer 22. The inner diameters of the two annular friction layers 23 are larger than the diameter of the shaft hole, so that annular areas 26 not occupied by the friction layers 23 are left on two surfaces of the middle layer 22.

[0034] At least one oil stirring hole 25 is provided in the annular area. Figure 3A and Figure 3B As shown, nine oil stirring holes 25 are provided on the annular region 26, and each of the oil stirring holes 25 is a circular hole. Preferably, the oil stirring holes 25 are evenly spaced and rotationally symmetrically distributed on a circle with the center of the dynamic friction plate 21 as the center. In order to open the oil stirring holes 25 on the annular region, the processing method used may be stamping, drilling, etc.

[0035] By adopting this dynamic friction plate 21, the following beneficial effects can be achieved:

[0036] 1) Lubricating oil or hydraulic oil (for lubrication / cooling) is stored in the lower part of the hydraulic brake housing 11, so the friction plates 20 and 21 are partially immersed in the lubricating oil or hydraulic oil (so the brake is called a wet hydraulic brake). It should be noted that the hydraulic oil used to drive the piston 19 to move is not connected to the lubricating oil or hydraulic oil in the housing. The oil stirring hole 25 fully stirs the oil gathered in the lower part of the housing 11 of the hydraulic brake 1 to reduce the oil temperature.

[0037] 2) Make the oil form a splash lubrication effect, thereby increasing the service life of the friction plate.

[0038] 3) The oil stirring hole 25 allows the lubricating oil or hydraulic oil to flow more smoothly inside the hydraulic brake 1, ensuring uniform lubrication of the friction plate and accelerating the oil injection speed. Specifically, Figure 1 and Figure 2A 1 shows the normal use posture of the hydraulic brake 1. However, during the assembly process of the hydraulic brake 1, especially during the oil filling process, the hydraulic brake 1 is in a state where the output shaft 13 is vertically downward. Figure 2A The hydraulic brake 1 is rotated 90 degrees counterclockwise from the perspective shown. In this state, if the dynamic friction plate 21 is not provided with the stirring hole 25, the oil poured during the assembly of the hydraulic brake 1 can only slowly penetrate along the very narrow gap between the dynamic / static friction plate and the housing 11 and the output shaft 13, so it may affect the assembly efficiency, and the oil may not fully penetrate between the friction plates when the user just starts using it after leaving the factory. This situation is more serious in winter when the oil viscosity is high. On the contrary, when the dynamic friction plate 21 is provided with the stirring hole 25, the poured oil can be poured downward quickly to avoid affecting the assembly efficiency and the user's use.

[0039] 4) The oil can flow along the grooves 24 provided on the surface of the friction layer 23, thereby enhancing the friction performance, taking away the heat generated by the friction and the friction material that falls off. Specifically, the friction material will inevitably wear out during use, and the friction material that falls off is generally in the form of small particles or microparticles. If these particles exist between the friction plates, it will cause an effect similar to "rolling friction" between the friction plates, reducing the friction coefficient.

[0040] [Modifications]

[0041] FIG. 4A to FIG. 4G They are front views of the dynamic friction plate 21 according to other embodiments (ie, modified examples) of the present application.

[0042] Specifically, although the shape, number and layout of the oil stirring holes 25 and the pattern of the grooves 24 on the friction layer 23 are described above, the above description is not restrictive. Those skilled in the art can modify the above structure as appropriate. For example, in addition to being circular, the oil stirring holes 25 can also be in the following shapes:

[0043] Rectangle, such as Figure 4A As shown, the symmetry axis of the rectangle along the length direction extends along the radial direction of the dynamic friction plate 21, and the symmetry axis of the rectangle along the width direction extends perpendicular to the radial direction of the dynamic friction plate; or

[0044] An isosceles triangle, such as Figure 4B As shown, the symmetry axis of the isosceles triangle extends along the radial direction of the dynamic friction plate 21, and the vertex angle of the isosceles triangle is closer to the center of the dynamic friction plate 21 than the base of the isosceles triangle; or

[0045] Isosceles trapezoid, such as Figure 4C As shown, the symmetry axis of the isosceles trapezoid extends along the radial direction of the dynamic friction plate 21, and the shorter base of the isosceles trapezoid is closer to the center of the dynamic friction plate 21 than the longer base of the isosceles trapezoid; or

[0046] Oval, such as Figure 4D As shown, the major axis of the ellipse extends along the radial direction of the dynamic friction plate 21, and the minor axis of the ellipse extends perpendicular to the radial direction of the dynamic friction plate 21; or

[0047] A fan ring shape, wherein the axis of symmetry of the fan ring shape (not shown in the figure) extends along the radial direction of the dynamic friction plate, and the shorter arc of the fan ring shape is closer to the center of the dynamic friction plate than the longer arc of the fan ring shape.

[0048] It can be noted that, according to actual needs, the number of the oil stirring holes 25 can be 6, 7, 8 or 9, etc.

[0049] In addition, if Figure 4D As shown, some of the plurality of grooves 24 extend along a spiral extending in a clockwise direction (eg, a logarithmic spiral), and other grooves extend along a spiral extending in a counterclockwise direction (eg, a logarithmic spiral), and these grooves intersect.

[0050] In addition, if Figure 4E As shown, the plurality of grooves 24 may be distributed in a concentric circle pattern.

[0051] In addition, if Figure 4F As shown, the plurality of grooves 24 may be distributed radially, with the center of the radiation being the center of the dynamic friction plate 21 .

[0052] In addition, if Figure 4GAs shown, multiple grooves 24 can be distributed in a “丰” shape, that is, some of the multiple grooves 24 are distributed in a concentric circle pattern, and some other grooves are distributed radially, so that these grooves form intersections.

[0053]

Industrial Applicability

[0054] The wet hydraulic brake of the present application can be used as a brake for wheels of various aerial work platforms (such as AWP scissor platforms).

[0055] In the above, the technical objectives, technical solutions and technical effects of the present application have been described in detail with reference to specific embodiments. It should be understood that the above embodiments are merely exemplary and not restrictive. Any modifications, equivalent replacements, improvements, etc. made by those skilled in the art within the spirit and principles of the present application are included within the protection scope of the present application.

Claims

1. A wet hydraulic brake (1), the wet hydraulic brake being suitable for an aerial work platform, the wet hydraulic brake comprising: A housing (11), a rear cover (12) mounted at the rear of the housing, an output shaft (13) passing through the front of the housing, a piston (19), a spring (18) and a clutch mechanism, wherein the piston can move forward and backward along the axial direction of the output shaft under the action of the elastic force of the spring and the hydraulic pressure, so that the clutch mechanism is engaged or disengaged. Wherein, the clutch mechanism comprises: a plurality of static friction plates (20), the outer peripheries of the static friction plates being fitted on the inner walls of the housing (11); and A plurality of dynamic friction plates (21), the shaft holes of the dynamic friction plates being spline-fitted on the outer periphery of the output shaft (13), The static friction plate (20) and the dynamic friction plate (21) are arranged alternately and are movable in the axial direction of the output shaft, thereby being pressed or loosened against each other. The dynamic friction plate is generally in the shape of a disk, and comprises: an intermediate layer (22), wherein an axial hole is provided at the center of the intermediate layer, the axial hole being suitable for cooperating with an output shaft (13) of the hydraulic brake; and two annular friction layers (23), the two annular friction layers being respectively bonded to two surfaces of the intermediate layer, the inner diameters of the two annular friction layers being larger than the diameter of the shaft hole, thereby leaving an annular area (26) on the intermediate layer that is not occupied by the friction layer, Wherein, at least one oil stirring hole (25) is opened on the annular area, and the processing method adopted for opening the oil stirring hole (25) is punching or drilling. The invention is characterized in that the at least one oil stirring hole (25) has the following shape: An isosceles trapezoid, wherein the symmetry axis of the isosceles trapezoid extends along the radial direction of the dynamic friction plate, and the shorter base of the isosceles trapezoid is closer to the center of the dynamic friction plate than the longer base of the isosceles trapezoid; or A fan ring shape, wherein the axis of symmetry of the fan ring extends along the radial direction of the dynamic friction plate, and the shorter arc of the fan ring shape is closer to the center of the dynamic friction plate than the longer arc of the fan ring shape.

2. The wet hydraulic brake (1) according to claim 1, characterized in that: A plurality of oil stirring holes (25) are distributed at equal intervals and in a rotationally symmetrical manner on a circumference with the center of the dynamic friction plate as the center.

3. The wet hydraulic brake (1) according to claim 1, characterized in that: The intermediate layer is made of steel, and the friction layer is made of friction material. The friction material is a copper-based material formed of copper powder, or a paper-based material formed of pulp.

4. The wet hydraulic brake (1) according to claim 1 or 2, characterized in that: A plurality of grooves are arranged on the surface of the friction layer.

5. The wet hydraulic brake (1) according to claim 4, characterized in that: A plurality of grooves extend along straight lines and form a cross; or Some of the plurality of grooves extend along a logarithmic spiral extending in a clockwise direction, and other grooves extend along a logarithmic spiral extending in a counterclockwise direction, and the grooves form a cross; or Multiple grooves are distributed in a concentric circle pattern; or The plurality of grooves are radially distributed, and the center of the radiation is the center of the friction plate; or Some of the plurality of grooves are distributed in a concentric circle pattern, and other grooves are distributed in a radial pattern, so that the grooves form an intersection.

6. The wet hydraulic brake (1) according to claim 1, characterized in that: Lubricating oil or hydraulic oil is poured into the housing, and the lubricating oil or hydraulic oil is capable of submerging at least a portion of the static friction plate (20) and the dynamic friction plate (21).

7. An aerial work platform, the aerial work platform having wheels, the wheels having brakes, It is characterized in that The brake is a wet hydraulic brake (1) according to any one of claims 1-6.

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