A drum brake for a construction machine

Abstract

The application relates to an engineering machinery drum brake, which comprises a mounting shell, a cross roller bearing, a cam roller flange, cam rollers, cam brake shoes, cam limiting grooves, a sector worm block, a worm and a roller connecting ring, the mounting shell comprises a worm mounting cavity, a brake component mounting cavity and brake shoe supporting columns, the inner ring of the cross roller bearing is mounted on the central bearing seat of the brake component mounting cavity, the outer ring of the cross roller bearing is provided with the sector worm block and the cam roller flange, the cam rollers are multiple, are uniformly mounted in roller holes of the cam roller flange and are in abutment with brake shoe cam surfaces of the cam brake shoes through return springs, the worm is axially fixed on the worm mounting cavity through double worm bearings, the cam brake shoes are multiple, are rotationally connected with multiple uniformly distributed brake shoe supporting columns through rotating pin shafts and the roller connecting ring connects the cam rollers in axial locking. Compared with the prior art, the engineering machinery drum brake has the advantages of good heat dissipation, good drainage and uniform wear.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicle braking technology, in particular to an engineering machinery drum brake. BACKGROUND

[0002] The drum brake is a common braking system in engineering machinery, which has a large friction contact area between the brake pad and the wheel hub, a long braking force arm, and can obtain strong braking torque, and is suitable for heavy engineering vehicle braking under low-speed heavy load conditions.

[0003] However, compared with the brake system such as the caliper brake, the traditional double-shoe drum brake has poor heat dissipation performance, is easy to accumulate heat under long-term braking work, and is easy to malfunction in high-temperature environment. Moreover, the double-shoe structure has the problem of difficulty in drainage and ventilation, and when the wheel hub is filled with water, it is not easy to drain, which affects the braking effect. In terms of braking control, the traditional drum brake adopts a push oil cylinder for driving, and the control effect is single, the control precision is poor, and the response is slow. In the braking work, the brake pad braking circle and the friction circle are not concentric, which leads to uneven wear, and the larger the wheel hub diameter, the more serious the phenomenon, so the application ability of the traditional drum brake in the scene of large-diameter wheel hub is poor. SUMMARY

[0004] The purpose of the present application is to overcome the defects of the prior art and provide an engineering machinery drum brake.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] An engineering machinery drum brake, comprising a mounting shell, a cross-roller bearing, a cam roller flange, a cam roller, a cam brake shoe, a cam limiting groove, a sector worm block, a worm and a roller connecting ring, the mounting shell comprising a worm mounting cavity, a brake component mounting cavity and a brake shoe support column, the inner ring of the cross-roller bearing is mounted on the central bearing seat of the brake component mounting cavity, the outer ring of the cross-roller bearing is mounted with the sector worm block and the cam roller flange, the cam roller has a plurality of cam rollers which are uniformly installed in the roller holes of the cam roller flange and are in contact with the brake shoe cam surface of the cam brake shoe through the return spring, the worm is axially fixed in the worm mounting cavity through the double worm bearing, the cam brake shoe has a plurality of cam brake shoes which are rotationally connected with a plurality of uniformly distributed brake shoe support columns through the rotating pin shaft, and the roller connecting ring connects the cam roller to realize axial locking.

[0007] Further, the two ports of the worm mounting cavity are respectively mounted with a driving motor and an absolute encoder, the shaft of the driving motor is connected with the shaft of the worm to realize rotary motion input, and the absolute encoder is connected with the shaft of the worm to realize position and speed feedback, thereby realizing cam brake shoe closing motion control.

[0008] Further, the driving motor, the worm and the absolute encoder form a cam pawl drum brake driving closed loop, the sector worm block reciprocates circumferentially forward and backward according to the set transmission ratio, corresponding to the brake and release processes of the brake respectively, the cam roller flange cam roller transmits force to the cam brake shoe, pushes the cam brake shoe to approach the roller brake disc around the brake shoe support column axis, and realizes the frictional contact of the brake pad and the roller brake disc.

[0009] Further, the cam brake shoe is multiple and uniformly distributed in a circumferential array, the cam brake shoe comprises a brake shoe mounting hole, a brake pad, a brake shoe back plate, a cam surface of the brake shoe and a spring mounting hole, the brake shoe back plate is further provided with a reinforcing rib, and the number of the cam brake shoes and the diameter of the brake shoe back plate are modularly selected and adjusted according to the rim diameter.

[0010] Further, the cam surface of the brake shoe is located in the inner ring of the cam brake shoe, the cross section of the cam surface of the brake shoe realizes linear compression motion mode through a preset Archimedes spiral, a return spring is buckled in the spring mounting hole to keep the cam surface of the brake shoe closely combined with the cam roller, and the roller connecting ring is used for axial locking, the cam limiting groove is mounted on the cam surface of the brake shoe and is responsible for limiting the movement range of the roller, and the brake pad is combined with the brake shoe back plate by the cam brake shoe and directly participates in the brake friction.

[0011] Further, the compression dynamic behavior of the brake pad is configured according to the cam cross section curve.

[0012] Further, the sector worm block retains part of the worm teeth and is concentrically mounted at the rear end of the outer ring of the cross roller bearing, the cam roller flange is axially fixed through hole cooperation with the front end of the outer ring of the cross roller bearing, and the cam rollers evenly divided in the circumferential direction of the cam roller flange are embedded between the cam surface of the brake shoe and the cam limiting groove.

[0013] Further, the sector worm block is meshed with the worm and is provided with a self-locking function, and the sector angle of the sector worm block is greater than the rotation stroke angle of the cam roller.

[0014] Further, the outer ring of the cross roller bearing, the sector worm block, the cam roller flange, the cam roller and the roller connecting ring are connected in a closed loop and are axially locked at the end.

[0015] Further, the customization parameters of the cam brake shoe include the number of brake unit distribution, the sector angle of single sector brake shoe, the brake shoe width and the cam cross section curve.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] 1) The present application adopts a modular multi-cam brake unit, evenly distributes the cam brake unit in a circumferential array, and allows users to customize the number of cam brake units and the angle of single sector brake shoes according to the diameter of the engineering vehicle, and keeps balanced distribution, effectively improves the heat dissipation and drainage capacity of the drum brake, maintains the uniformity of wear of each brake pad, improves the braking stability and service life, and better meets the braking needs of large-diameter low-speed heavy-load engineering vehicles.

[0018] 2) The brake provided by the present application can realize driving motor power input and sensor speed feedback, realize precise electronic control, and has stable control performance; and the cam curve can be designed to customize the brake pressing mode, and the control mode is various. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 FIG. 1 is a structural schematic diagram of an engineering machinery drum brake according to an embodiment of the present application;

[0020] Figure 2 FIG. 2 is an exploded view of an engineering machinery drum brake according to an embodiment of the present application;

[0021] Figure 3 FIG. 3 is a structural schematic diagram of a cam brake shoe according to an embodiment of the present application;

[0022] Figure 4 FIG. 4 is a structural schematic diagram of a single cam brake unit according to an embodiment of the present application;

[0023] Figure 5 FIG. 5 is a structural schematic diagram of power input of a worm and gear mechanism according to an embodiment of the present application;

[0024] Figure 6a FIG. 6 is a cross-section line indication diagram of a worm and gear mechanism according to an embodiment of the present application.

[0025] Figure 6b FIG. 7 is a cross-sectional view of a worm and gear mechanism according to an embodiment of the present application.

[0026] Marked in the figure: 1, mounting shell; 2, cross roller bearing; 3, cam roller flange; 4, cam roller; 5, cam brake shoe; 6, cam limiting groove; 7, sector worm block; 8, worm; 9, roller connecting ring; 10, driving motor; 11, absolute encoder; 12, return spring; 13, worm bearing; 14, rotating pin shaft; 15, rotating pin shaft locking nut; 21, cross roller bearing inner ring; 22, cross roller bearing outer ring; 41, roller clamp spring; 51, brake shoe mounting hole; 52, brake pad; 53, brake shoe back plate; 54, brake shoe cam surface; 55, spring mounting hole; 56, brake shoe bearing; 101, worm mounting cavity; 102, brake component mounting cavity; 103, center bearing seat; 104, brake shoe supporting column. DETAILED DESCRIPTION

[0027] The present application will be described in detail below with reference to the drawings and specific embodiments. The embodiments are implemented on the premise of the technical solutions of the present application, and give detailed implementation modes and specific operation processes, but the protection scope of the present application is not limited to the following embodiments.

[0028] Embodiment 1

[0029] The present application is a drum brake for engineering machinery, as shown in Figure 1 and Figure 2 , comprising a mounting shell 1, a cross roller bearing 2, a cam roller flange 3, a cam roller 4, a plurality of cam brake shoes 5, a cam limiting groove 6, a sector worm block 7, a worm 8 and a roller connecting ring 9, the mounting shell 1 comprises a worm mounting cavity 101 and a brake component mounting cavity 102, the cross roller bearing inner ring 21 is mounted on the central bearing seat 103 of the brake component mounting cavity 102, the cross roller bearing outer ring 22 is mounted with the sector worm block 7 and the cam roller flange 3, the cam roller 4 is uniformly mounted in the roller hole of the cam roller flange 3 and is in contact with the brake shoe cam surface 51 of the cam brake shoe 5 through the return spring 11, the worm 8 is axially fixed in the worm mounting cavity 101 through the double worm bearing 13, the plurality of cam brake shoes 5 are rotationally connected with a plurality of uniformly distributed support columns 104 through the rotating pin shaft 14, and the roller connecting ring 9 connects the cam roller 4 to realize axial locking.

[0030] As shown in Figure 3 , the number of cam brake shoes 5 is various, and they are uniformly circumferentially arrayed around the cam roller flange 3, the cam brake shoe 5 comprises a brake shoe mounting hole 51, a brake pad 52, a brake shoe back plate 53, a brake shoe cam surface 54 and a spring mounting hole 55, and the brake shoe back plate 53 is further provided with a reinforcing rib. The number of cam brake shoes 5 and the diameter of brake shoe back plate 53 can be modularly selected and adjusted according to the rim diameter, and this scheme is suitable for different diameter of wheeled engineering equipment. The brake shoe cam surface 54 is located in the inner ring of the cam brake shoe 5, and the cam surface can be designed with a section curve to preset the pressing motion mode, so as to customize the braking dynamic, for example, the cam section curve is an Archimedes spiral, which can convert the constant speed circumferential motion of the cam roller flange 3 into the radial constant speed pressing motion of the cam surface contact point.

[0031] As shown in Figure 4As shown, the single set of cam brake mechanism includes cam roller flange 3, cam roller 4, cam brake shoe 5, cam limit groove 6, return spring 11 and roller connecting ring 9. The pre-tightening force of the return spring 11 keeps the cam surface 54 of the brake shoe in close contact with the cam roller 4, and is axially locked by the roller connecting ring 9. The cam limit groove 6 can be fixed on both sides of the cam surface 54 of the brake shoe to limit the movement range of the roller. The brake pad 52 is installed on the brake shoe back plate 53. The cross roller bearing outer ring 22, the sector worm block 7, the cam roller flange 3, the plurality of cam rollers 4, and the roller connecting ring 9 are connected in a closed loop to form a brake cam mechanism, and are axially locked at the end.

[0032] As shown in Figure 5 , Figure 6a and Figure 6b , the sector worm block 7 retains part of the worm gear teeth, is installed in the recess at the rear end of the cross roller bearing outer ring 22, and the cam roller flange 3 is axially fixed with the cross roller bearing outer ring 22 through hole fitting at the front end. The extended shaft neck of the cam roller flange 3 can be lightened.

[0033] The two ports of the worm installation cavity 101 can respectively install the driving motor 10 and the absolute encoder 11. The motor shaft connects the worm 8 shaft to realize rotary motion input, and the absolute encoder connects the worm 8 shaft to realize position and speed feedback, which can realize precise brake pressing amount control. The sector worm block 7 is engaged with the worm 8, and the sector angle of the sector worm block 7 is greater than the rotation stroke angle of the cam roller 4.

[0034] The driving motor 10, the worm 8 and the absolute encoder 11 form a closed loop of the cam shoe drum brake drive. The brake and release processes are respectively implemented by forward and reverse rotation. The rotary motion of the worm 7 is converted into the reciprocating circumferential swing of the sector worm block 7, and then the force is transmitted to the cam brake shoe 5 through the cam roller flange 3 and the cam roller 4, which pushes the cam brake shoe 5 to move close to the roller brake disc around the brake shoe support column 104 axis, realizing the frictional contact between the brake pad 52 and the roller brake disc.

[0035] In the actual braking process, the vehicle braking ECU can control the driving motor 10, and the absolute encoder 11 feedback realizes control. The electric control algorithm can control the rotation speed of the worm 8, and drag the worm 8 to rotate the desired angle. The driving force is transmitted through the worm 8, the sector worm block 7, the cross roller bearing outer ring 22, the cam roller flange 3, the cam roller 4, the cam brake shoe 5, so as to realize the motion and force transmission route, thereby accurately and quantitatively controlling the arc-shaped brake pad 52 to press into the roller brake disc, and the friction force generated provides the braking torque. The cam brake shoe 5, the cam limiting groove 6 and the cam roller 4 can form a set of cam brake units. The engineering machinery drum brake provided by the application can include multiple sets of cam brake units, and the shape of the brake shoe cam surface 54 can be customized according to the braking dynamic demand, so as to customize the pressing dynamic behavior of the brake pad 52, such as linear, quadratic polynomial and the like.

[0036] The application disassembles the traditional two-hinged brake shoe, sets the modularized multiple cam brake units, uniformly distributes the cam brake units in a circumferential array, and users can customize the number of cam brake units and the angle of single sector brake shoe according to the diameter of the engineering vehicle, and keep balanced distribution. The block processing adopted by the brake of the application increases the heat transfer path, reduces heat accumulation, the smaller radian sector brake pad reduces the unevenness of brake wear, and the brake can be more suitable for the braking use scene of heavy load engineering vehicles with large diameter hubs. The engineering machinery drum brake in the application can effectively improve the braking life and stability of the drum brake.

[0037] In the actual release of the brake process, the vehicle braking ECU can control the driving motor 10 to reverse, through the same power transmission chain, so that multiple cam rollers 4 retreat, and the circumferential array distributed cam brake shoes 5 rotate under the joint action of the return spring 12 and the cam limiting groove 6, until they return to the initial position, finally the brake pad 52 keeps the initial gap with the roller brake disc, no friction force is generated, and the output braking torque is stopped.

[0038] The above describes the preferred embodiments of the application in detail. It should be understood that those skilled in the art can make many modifications and changes without creative labor according to the concept of the application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment on the basis of the prior art according to the concept of the application should be within the protection scope determined by the claims.

Claims

1. An engineering machine drum brake, characterised in that, The application relates to a cammed shoe drum brake, which comprises a mounting shell (1), a cross roller bearing (2), a cam roller flange (3), cam rollers (4), cammed brake shoes (5), cam limiting grooves (6), a sector worm block (7), a worm (8) and a roller connecting ring (9), wherein the mounting shell (1) comprises a worm mounting cavity (101), a brake component mounting cavity (102) and brake shoe supporting columns (104), the cross roller bearing inner ring (21) is mounted on the central bearing seat (103) of the brake component mounting cavity (102), the cross roller bearing outer ring (22) is mounted with the sector worm block (7) and the cam roller flange (3), the cam rollers (4) are uniformly mounted in roller holes of the cam roller flange (3) and are in close contact with cammed shoe cam surfaces (54) of the cammed brake shoes (5) through return springs (12), the cammed brake shoes (5) are rotationally connected with a plurality of uniformly distributed brake shoe supporting columns (104) through rotating pin shafts (14), the cammed brake shoes (5) are uniformly circumferentially arranged and comprise the cammed shoe cam surfaces (54), the cammed shoe cam surfaces (54) are located in inner rings of the cammed brake shoes (5), the cross section of the cammed shoe cam surfaces (54) realizes linear pressing motion mode through a preset Archimedes spiral, the cammed shoe cam surfaces (54) are provided with the cam limiting grooves (6) and are responsible for limiting the movement range of the cam rollers (4), the circumferentially divided cam rollers (4) of the cam roller flange (3) are embedded between the cammed shoe cam surfaces (54) and the cam limiting grooves (6), the sector worm block (7) is engaged with the worm (8), the sector angle of the sector worm block (7) is greater than the rotation stroke angle of the cam rollers (4), the sector worm block (7) reciprocatingly and circumferentially swings in a positive and negative mode according to a set transmission ratio and corresponds to brake and release processes of the brake, force is transmitted to the cammed brake shoes (5) through the cam roller flange (3) and the cam rollers (4), the cammed brake shoes (5) are pushed to move close to a roller brake disc around the brake shoe supporting columns (104), frictional contact between brake pads (52) and the roller brake disc is realized, the worm (8) is axially fixed in the worm mounting cavity (101) through double worm bearings (13), and the roller connecting ring (9) connects the cam rollers (4) and realizes axial locking.

2. A drum brake for a construction machine according to claim 1, wherein Two ports of the worm mounting cavity (101) are respectively provided with a driving motor (10) and an absolute encoder (11), the shaft of the driving motor (10) is connected with the shaft of the worm (8) to realize rotation motion input, the absolute encoder (11) is connected with the shaft of the worm (8) to realize position and speed feedback, and cammed brake shoe (5) closing motion control is realized.

3. A drum brake for a mobile machine according to claim 2 wherein, The driving motor (10), the worm (8) and the absolute encoder (11) form a cammed shoe drum brake driving closed loop.

4. The drum brake for mobile machines defined in claim 1, wherein The cam brake shoe (5) further comprises a brake shoe mounting hole (51), a brake pad (52), a brake shoe back plate (53) and a spring mounting hole (55), the brake shoe back plate (53) is further provided with a reinforcing rib, the number of the cam brake shoe (5) and the diameter of the brake shoe back plate (53) are modularly selected and adjusted according to the rim diameter.

5. A drum brake for a mobile machine as set forth in claim 4 wherein, The return spring (12) is buckled in the spring mounting hole (55) to keep the brake shoe cam surface (54) closely contact with the cam roller (4), the cam brake shoe (5) contacts the brake pad (52) to the brake shoe back plate (53) and directly participates in the brake friction.

6. The drum brake for mobile machines defined in claim 4 wherein, The pressing dynamic behavior of the brake pad (52) is configured according to the cam cross-sectional curve.

7. The drum brake for mobile machines defined in claim 1 wherein, The sector worm block (7) retains part of the worm gear teeth and is concentrically installed at the rear end of the cross roller bearing outer ring (22), the cam roller flange (3) is axially fixed by being axially fixed with the front end of the cross roller bearing outer ring (22).

8. The drum brake for mobile machines defined in claim 1 wherein, The sector worm block (7) and the worm (8) are provided with a self-locking function.

9. The drum brake for mobile machines defined in claim 1 wherein, The cross roller bearing outer ring (22), the sector worm block (7), the cam roller flange (3), the cam roller (4) and the roller connecting ring (9) are connected in a closed loop and axially locked at the end.

10. The drum brake for mobile machines defined in claim 1, wherein, The customization parameters of the cam brake shoe (5) include the number of brake unit distribution, the sector angle of single sector brake shoe, the brake shoe width and the cam cross-sectional curve.

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