CN113565906A

CN113565906A - Dynamic friction plate, wet hydraulic brake and aerial work platform

Info

Publication number: CN113565906A
Application number: CN202010360567.5A
Authority: CN
Inventors: 何平; 李历; 李琳桦; 陈峻源; 杨茜
Original assignee: Danfoss Power Solutions Jiangsu Co Ltd
Current assignee: Danfoss Power Solutions Jiangsu Co Ltd
Priority date: 2020-04-29
Filing date: 2020-04-29
Publication date: 2021-10-29

Abstract

The application discloses a dynamic friction plate suitable for a wet hydraulic brake, which is generally disc-shaped and comprises a middle layer and two annular friction layers. And the center of the middle layer is provided with a shaft hole which is used for being matched with an output shaft of the hydraulic brake. The two friction layers are respectively joined on both surfaces of the intermediate layer, and the inner diameters of the two friction layers are larger than the diameter of the shaft hole, so that annular regions not occupied by the friction layers are left on both surfaces of the intermediate layer. At least one oil stirring hole is arranged on the annular area. The application also discloses a wet hydraulic brake with the dynamic friction plate arranged inside and an aerial work platform adopting the wet hydraulic brake. Through the technical scheme who adopts this application, can make the movable friction piece dispel the heat more fast, the inside circulation of lubricating oil or hydraulic oil at wet-type hydraulic actuator of being convenient for has increased the life of movable friction piece.

Description

Dynamic friction plate, wet hydraulic brake and aerial work platform

Technical Field

The present invention relates to a dynamic friction plate, a wet hydraulic brake in which the dynamic friction plate is provided, and an aerial work platform using the wet hydraulic brake.

Background

A brake is a device having a function of decelerating, stopping, or maintaining a stopped state of a moving member (or a moving machine).

As shown in fig. 1 and 2A, 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, and the like 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 sheet 20 is fitted on the inner wall of the housing 11, and the static friction sheet 20 may be made of steel, for example. The dynamic friction plates 21 are clearance-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, the

friction plates

20 and 21 are alternately arranged and can be pressed against or released from each other in the front-rear direction.

Specifically, the piston 19 is movable back and forth by the elastic force of the spring 18 and the hydraulic pressure in the piston chamber, so that the clutch mechanism is engaged or disengaged, and thus the output shaft 13 can be selectively allowed to rotate or prevented from rotating. An output shaft 13 extends from the front of the housing 11 and is connected by a flat key 14 and a lock nut 15 to other associated components, such as a hub or brake disc (not shown) of the aerial platform/vehicle. The rear cover 12 is fitted behind the housing 11. The hydraulic brake 1 also has an oil port 16. The oil port 16 communicates with a hydraulic oil passage provided inside the hydraulic brake 1, and may communicate with an external hydraulic oil supply/discharge apparatus to supply and discharge hydraulic oil inside the hydraulic brake to the outside. It is to be noted that the oil port 16 shown in fig. 1 and 2A has been temporarily sealed by the sealing plug 17, and thus the oil port 16 in the open state is not shown in fig. 1 and 2A.

As shown in fig. 2A and 2B, when no hydraulic oil is applied to the oil port 16, the piston 19 presses the

friction plates

20 and 21 by the elastic force of the spring 18, and thus a braking torque is generated by the frictional force between the

friction plates

20 and 21. When it is necessary to release the hydraulic brake 1, hydraulic oil is supplied to the oil port 16, the piston 19 releases the

friction plates

20 and 21 pressed against each other by the hydraulic pressure, and the frictional force between the

friction plates

20 and 21 disappears, thereby releasing the hydraulic brake 1.

In the conventional hydraulic brake of this type, a large amount of heat is generated on the friction plates during braking. Therefore, the existing friction plate has poor heat dissipation effect and short service life.

Therefore, the important matters to be considered in the design scheme of the application include: 1) how to make the heat radiate out from the friction plate more quickly to increase the service life of the friction plate; 2) how can the new design scheme reach better radiating effect under the condition of keeping all performances of current friction disc.

Disclosure of Invention

To solve the above technical problems and potentially other technical problems, according to one aspect of the present application, a dynamic friction plate for a wet hydraulic brake for an aerial work platform is provided. The dynamic friction plate is generally disc-shaped. The dynamic friction plate comprises: the center of the middle layer is provided with a shaft hole which is suitable for being matched with an output shaft of the hydraulic brake; and two annular friction layers respectively engaged on both surfaces of the intermediate layer, the two annular friction layers having an inner diameter larger than that of the shaft hole, thereby leaving annular regions on both surfaces of the intermediate layer unoccupied by the friction layers. At least one oil stirring hole is formed in the annular area.

The at least one oil agitating hole may have the following shape: a circular shape; 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 is perpendicular to the radial direction of the dynamic friction plate; or the rectangle is provided with a symmetrical axis along the length direction and extends along the radial direction of the dynamic friction plate, and a symmetrical axis along the width direction of the rectangle is vertical to the radial direction of the dynamic friction plate; the symmetry axis 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 bottom edge of the isosceles triangle; or an isosceles trapezoid, a symmetry axis of the isosceles trapezoid extends along a radial direction of the dynamic friction plate, and a shorter base side of the isosceles trapezoid is closer to a center of the dynamic friction plate than a longer base side of the isosceles trapezoid; or a sector ring shape, a symmetry axis of the sector ring shape extends in a radial direction of the dynamic friction plate, and a shorter arc of the sector ring shape is closer to a center of the dynamic friction plate than a longer arc of the sector ring shape.

The number of the oil stirring holes can be more than one, and the oil stirring holes are distributed on the circumference which takes the center of the dynamic friction plate as the center of a circle at equal intervals and in a rotational symmetry mode.

In particular, the intermediate layer may be made of steel and the friction layer of friction material. For example, the friction material may be a copper-based material formed from copper powder, or a paper-based material formed from pulp.

A plurality of grooves may be provided on a surface of the frictional layer. The grooves may extend along straight lines and form a crisscross. Alternatively, some of the plurality of grooves extend along a clockwise expanding logarithmic spiral, others extend along a counterclockwise expanding logarithmic spiral, and the grooves form an intersection. Optionally, the plurality of grooves are distributed in a pattern of concentric circles. Optionally, the grooves are radially distributed, and a radial center is a center of the friction plate. Alternatively, some of the plurality of grooves are arranged in a concentric pattern and others are arranged in a radial pattern such that the grooves intersect.

According to another aspect of the present application, a wet hydraulic brake suitable for use with an aerial work platform is provided. The wet hydraulic brake includes: the clutch mechanism comprises a shell, a rear cover installed at the rear of the shell, an output shaft penetrating through the front of the shell, a piston, a spring and a clutch mechanism. The piston can move back and forth along the axial direction of the output shaft under the action of the elastic force and the hydraulic pressure of the spring, so that the clutch mechanism is engaged or disengaged. The clutch mechanism includes: a plurality of static friction plates, the outer peripheries of which are fitted on the inner wall of the case; and a plurality of dynamic friction plates as described above, the shaft holes of which are spline-fitted on the outer periphery of the output shaft. The static friction plates and the dynamic friction plates are alternately arranged and are capable of moving in the axial direction of the output shaft so as to be pressed against or released from each other.

Specifically, lubricating oil or hydraulic oil is filled in the shell, and the lubricating oil or the hydraulic oil can submerge at least one part of the static friction plate and the dynamic friction plate.

In accordance with another aspect of the present application, an aerial work platform is provided having wheels with brakes. The brake is a wet hydraulic brake as described hereinbefore.

This application can obtain following beneficial effect through adopting above-mentioned technical scheme:

1) the heat dissipation area of the dynamic friction plate is increased, so that the dynamic friction plate can dissipate heat more quickly.

2) Lubricating oil or hydraulic oil can more smoothly circulate in the brake, so that the friction plate is uniformly lubricated, and the filling speed of the lubricating oil can be increased.

3) The oil gathered at the lower part of the shell of the hydraulic brake is fully stirred, so that the temperature of the oil is reduced.

4) The oil forms a splash lubrication effect, and the service life of the dynamic friction plate is prolonged.

Drawings

To facilitate the reader's understanding of the technical aspects of the present application, the present application is described in more detail below based on exemplary embodiments and with reference to the accompanying drawings. The same or similar reference numbers are used in the drawings to refer to the same or similar parts. It should be understood that the drawings are merely schematic and that the dimensions and proportions of elements in the drawings are not necessarily precise.

Fig. 1 is a schematic perspective view of a hydraulic brake according to an embodiment of the present application.

Fig. 2A is a cross-sectional view of the hydraulic brake of fig. 1 taken along a vertical center plane.

Fig. 2B is a partially enlarged view of the region B in fig. 2A.

Fig. 3A and 3B are a perspective view and a front view, respectively, of a dynamic friction plate in the hydraulic brake in fig. 2A.

FIG. 3C is a cross-sectional view of the dynamic friction plate taken along plane C-C in FIG. 3B.

Fig. 3D is a partially enlarged view of the region D in fig. 3C.

Fig. 4A, 4B, 4C, 4D, 4E, 4F and 4G are front views of dynamic friction plates according to other embodiments of the present application, respectively.

Detailed Description

The general configuration of a hydraulic brake 1 according to one embodiment of the present application has been described in the "background" section of the present specification with reference to fig. 1, 2A, and 2B. The applicant hereby gives notice that this section is both a description of the background art of the present application and forms part of a specific embodiment of the present application. This application is for the sake of brevity only and is not repeated here.

The configuration of the dynamic friction plates 21 in the hydraulic brake 1 will be described next with reference to fig. 3A to 3D. Fig. 3A and 3B are a perspective view and a front view, respectively, of the dynamic friction plate 21 in the hydraulic brake 1 in fig. 2A. Fig. 3C is a sectional view of the dynamic friction plate 21 taken along the plane C-C in fig. 3B. Fig. 3D is a partially enlarged view of the region D in fig. 3C.

As shown in fig. 3A, 3B, and 3C, the dynamic friction plate 21 is generally disc-shaped and includes an intermediate layer 22 and two annular friction layers 23. A shaft hole is provided in the center of the intermediate layer 22. The inner periphery of the shaft hole is provided with spline grooves and is suitable for forming clearance fit with the splines on the output shaft 13 of the hydraulic brake 1.

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

As shown in fig. 3C and 3D, two annular friction layers 23 are respectively bonded on both surfaces of the intermediate layer 22. The two annular friction layers 23 have an inner diameter greater than the diameter of the shaft bore, leaving annular regions 26 on both surfaces of the intermediate layer 22 that are not occupied by the friction layers 23.

At least one oil stirring hole 25 is formed in the annular region. As shown in fig. 3A and 3B, 9 oil stirring holes 25 are opened in the annular region 26, and each oil stirring hole 25 is a circular hole. Preferably, the oil stirring holes 25 are distributed at equal intervals and in rotational symmetry on a circumference centered on the center of the dynamic friction plate 21. In order to open the oil stirring holes 25 in the annular region, the machining method may be punching, drilling, or the like.

By adopting the dynamic friction plate 21, the following beneficial effects can be obtained:

1) lubricating oil or hydraulic oil (for lubrication/cooling) is stored in the lower portion of the hydraulic brake housing 11, and thus the

friction plates

20 and 21 are partially soaked in the lubricating oil or hydraulic oil (so the brake is referred to as a wet hydraulic brake). It should be noted that the hydraulic oil used to drive the movement of the piston 19 is not in communication with the lubricating oil or hydraulic oil in the housing. The oil stirring hole 25 sufficiently stirs the oil collected at the lower portion of the housing 11 of the hydraulic brake 1, so that the temperature of the oil is reduced.

2) The oil forms a splash lubrication effect, so that the service life of the friction plate is prolonged.

3) The oil stirring hole 25 enables lubricating oil or hydraulic oil to flow more smoothly inside the hydraulic brake 1, so that the friction plate is guaranteed to be uniform in lubrication, and the filling speed of the oil can be increased. Specifically, fig. 1 and 2A show the normal use posture of the hydraulic brake 1. However, during assembly of the hydraulic brake 1, particularly during filling of oil, the hydraulic brake 1 is in a state where the output shaft 13 is directed vertically downward, that is, in a state where the hydraulic brake 1 is rotated 90 degrees counterclockwise in the perspective shown in fig. 2A. In this state, if the oil agitating holes 25 are not formed in the dynamic friction plates 21, oil poured during the assembly of the hydraulic brake 1 may slowly infiltrate only along very narrow gaps between the dynamic/static friction plates and the housing 11 and the output shaft 13, so that the assembly efficiency may be deteriorated, and the oil may not sufficiently infiltrate between the friction plates when a user starts using the hydraulic brake immediately after the factory shipment. This is especially the case in winter where the viscosity of the oil is high. On the contrary, under the condition that oil stirring hole 25 is opened on dynamic friction piece 21, the filled oil can be filled downwards rapidly, avoiding influencing packaging efficiency and user's use.

4) The oil may flow along the surface of the frictional layer 23 provided with a plurality of grooves 24, thereby enhancing frictional performance, removing heat generated by friction, and removing dropped friction material. In particular, the friction material inevitably wears in use, and the falling friction material is generally in the form of small particles or granules. If these particles are present between the friction plates, an effect similar to "rolling friction" is caused between the friction plates, reducing the friction coefficient.

[ PROFILE EXAMPLES ]

Fig. 4A to 4G are front views of the dynamic friction plate 21 according to other embodiments (i.e., modifications) of the present application, respectively.

Specifically, although the shape, number, and layout of the oil agitating holes 25 and the pattern of the grooves 24 on the friction layer 23 are described in the foregoing, the above-described case is not limitative. Those skilled in the art may modify the above-described structure as appropriate. For example, the oil agitating holes 25 may have the following shape in addition to the circular shape:

a rectangle, as shown in fig. 4A, the longitudinal axis of symmetry of which extends in the radial direction of the dynamic friction plate 21 and the width axis of symmetry of which extends perpendicular to the radial direction of the dynamic friction plate; or

An isosceles triangle, as shown in fig. 4B, the symmetry axis of which extends in the radial direction of the dynamic friction plate 21, and the vertex angle of which is closer to the center of the dynamic friction plate 21 than the base of which; or

An isosceles trapezoid, as shown in fig. 4C, the symmetry axis of which extends in the radial direction of the dynamic friction plate 21, and the shorter base of which is closer to the center of the dynamic friction plate 21 than the longer base of which; or

An ellipse shape, as shown in fig. 4D, the major axis of which extends in the radial direction of the dynamic friction plate 21 and the minor axis of which extends perpendicular to the radial direction of the dynamic friction plate 21; or

A sector ring shape (not shown in the figure) having a symmetry axis extending in a radial direction of the dynamic friction plate, and a shorter arc of the sector ring shape being closer to a center of the dynamic friction plate than a longer arc of the sector ring shape.

It is noted that the number of the oil agitating holes 25 may be 6, 7, 8, or 9, etc., according to actual needs.

In addition, as shown in fig. 4D, some of the plurality of grooves 24 extend along a clockwise-expanding spiral (e.g., logarithmic spiral), others extend along a counterclockwise-expanding spiral (e.g., logarithmic spiral), and the grooves form intersections.

Additionally, as shown in FIG. 4E, the plurality of grooves 24 may be distributed in a concentric circular pattern.

In addition, as shown in fig. 4F, the plurality of grooves 24 may be radially distributed, and the radial center is the center of the dynamic friction plate 21.

Additionally, as shown in fig. 4G, the plurality of grooves 24 may be arranged in a "torx" pattern, i.e., some of the plurality of grooves 24 are arranged in a concentric pattern and some of the plurality of grooves are arranged in a radial pattern such that the grooves intersect.

[ INDUSTRIAL APPLICABILITY ]

The wet hydraulic brake of the present application may be used as a brake for the wheels of a variety of aerial work platforms (e.g., AWP scissor platforms).

The technical objects, technical solutions and technical effects of the present application have been described in detail above with reference to specific embodiments. It should be understood that the above-described embodiments are exemplary only, and not limiting. Any modification, equivalent replacement, improvement and the like made by those skilled in the art within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A dynamic friction plate (21) adapted for use in a wet hydraulic brake (1) of an aerial work platform, the dynamic friction plate being generally disc-shaped, the dynamic friction plate comprising:

an intermediate layer (22) provided with a shaft hole at the center thereof, the shaft hole being adapted to mate with an output shaft (13) of the hydraulic brake; and

two annular friction layers (23) respectively engaged on both surfaces of the intermediate layer, the two annular friction layers having an inner diameter larger than the diameter of the shaft hole so as to leave an annular region (26) on the intermediate layer unoccupied by the friction layers,

the oil mixing device is characterized in that at least one oil mixing hole (25) is formed in the annular area.

2. Dynamic friction plate (21) according to claim 1, characterized in that said at least one oil stirring hole is shaped as follows:

a circular shape; or

The long axis of the ellipse extends along the radial direction of the dynamic friction plate; or

The symmetry axis of the rectangle along the length direction extends along the radial direction of the dynamic friction plate; or

An isosceles triangle, wherein the symmetry axis 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 bottom edge of the isosceles triangle; or

An isosceles trapezoid, a symmetry axis of the isosceles trapezoid extending along a radial direction of the dynamic friction plate, and a shorter base side of the isosceles trapezoid being closer to a center of the dynamic friction plate than a longer base side of the isosceles trapezoid; or

A sector ring shape, a symmetry axis of the sector ring shape extending along a radial direction of the dynamic friction plate, and a shorter arc of the sector ring shape being closer to a center of the dynamic friction plate than a longer arc of the sector ring shape.

3. Dynamic friction plate (21) according to claim 1 or 2, characterized in that the number of oil stirring holes is more than one, these oil stirring holes being equally spaced, rotationally symmetrically distributed on a circumference centered on the center of the dynamic friction plate.

4. Dynamic friction plate (21) according to claim 1 or 2, characterized in that said intermediate layer is made of steel and said friction layer is made of friction material,

the friction material is a copper-based material formed from copper powder or a paper-based material formed from pulp.

5. Dynamic friction plate (21) according to claim 1 or 2, characterized in that a plurality of grooves are provided on the surface of the friction layer.

6. Dynamic friction plate (21) according to claim 3, characterized in that a plurality of grooves are provided on the surface of the friction layer.

7. Dynamic friction plate (21) according to claim 5,

the grooves extend along straight lines and form crisscross intersections; or

Some of the plurality of grooves extend along a clockwise expanding logarithmic spiral, others extend along a counterclockwise expanding logarithmic spiral, and the grooves form an intersection; or

The grooves are distributed in a concentric circle mode; or

The grooves are radially distributed, and the radiation center is the center of the friction plate; or

Some of the plurality of grooves are arranged in a concentric pattern and others are arranged in a radial pattern such that the grooves intersect.

8. Dynamic friction plate (21) according to claim 6,

the grooves extend along straight lines and form crisscross intersections; or

The grooves are distributed in a concentric circle mode; or

9. A wet hydraulic brake (1) adapted for use on an aerial work platform, comprising: a housing (11), a rear cover (12) mounted at the rear of the housing, an output shaft (13) penetrating the front of the housing, a piston (19), a spring (18), and a clutch mechanism, the piston being movable back and forth in the axial direction of the output shaft under the elastic force and hydraulic pressure of the spring so that the clutch mechanism is engaged or disengaged,

characterized in that, the clutching mechanism includes:

a plurality of static friction plates (20) whose outer peripheries are fitted on an inner wall of the case (11); and

a plurality of dynamic friction plates (21) according to any one of claims 1 to 8, the shaft holes of which are spline-fitted on the outer periphery of the output shaft (13),

wherein the static friction plates (20) and the dynamic friction plates (21) are alternately arranged and are movable in the axial direction of the output shaft so as to be pressed against or released from each other.

10. Wet hydraulic brake (1) according to claim 9, characterized in that said housing is filled with a lubricating oil or hydraulic oil capable of submerging at least a portion of said static (20) and dynamic (21) pads.

11. An aerial work platform, the work vehicle having wheels with brakes,

characterized in that the brake is a wet hydraulic brake (1) according to claim 9 or 10.