Self-adjusting drum brake for electric vehicles

Abstract

The application discloses a self-adjusting drum brake for electric vehicles, which comprises a brake chamber shell assembly, a friction shoe block assembly, a camshaft, a rocker arm, a dialing mechanism and a self-adjusting mechanism. The inside of the brake chamber shell assembly is provided with the friction shoe block assembly. The outside of the cam body is provided with a tooth-shaped structure. The dialing mechanism dials the rotation of the camshaft. The self-adjusting mechanism keeps the original position and moves the same angle relative to the dialing mechanism. The dialing mechanism and the brake chamber shell assembly are further provided with a return spring. The dialing mechanism is reset under the action of the return spring. The camshaft keeps an angle under the adjustment of the self-adjusting mechanism. The dialing mechanism and the self-adjusting mechanism are adapted and adjusted through the tooth-shaped structure provided on the outside of the cam body. The problem that the gap between the shoe block assembly and the wheel hub becomes larger after long-time wear of the shoe block assembly of the existing brake, the brake gap is not adjusted in time and accurately, and the hand feeling is heavy is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of motor vehicle or electric vehicle brake, in particular to a self-adjusting drum brake for electric vehicle. BACKGROUND

[0002] The drum brake is driven by the rotation of the rocker arm to rotate the camshaft, drive the two side shoe assembly to open and close to the brake drum, the friction between the brake drum and the shoe group makes the wheel stop rotating. After long-term use, the brake line will be lengthened under the action of the elastic force, and the gap between the shoe assembly and the wheel hub will become larger after long-term wear. At this time, the brake performance will be reduced and the brake will fail. The brake line screw is usually adjusted manually to tighten the brake line or the brake is replaced. When adjusting the brake gap manually, it is difficult to ensure timeliness and accuracy.

[0003] The brake gap automatic adjustment device is widely used in the field of automobiles. However, it is rarely used in the drum brake of electric vehicles, tricycles and motorcycles in the prior art.

[0004] The publication number CN106050999B has an automatic adjustment brake gap function: the crank is composed of a driving arm and a driven arm, the driven arm and the driving arm are sleeved on the camshaft, the driven arm is fixedly connected with the camshaft, the driving arm is movably connected with the camshaft, the driving arm is provided with a ratchet mechanism, the center of the ratchet is provided with a threaded hole, the driven arm is provided with an adjusting screw, the adjusting screw is sleeved in the threaded hole of the ratchet, the ratchet structure, the adjusting screw and the limiting block on the hub brake cover are matched to automatically adjust the hub brake gap. When the driving arm moves to the set angle, the ratchet rocker lever head part contacts the limiting block, the ratchet rocker lever rotates, so that the ratchet moves one tooth on the ratchet.

[0005] The structure of the ratchet device designed by the driving and driven crank is complex and heavy, and the adjustment is matched with the limiting block, the resistance is large during braking, and the hand feeling is heavy. The adjusting screw is a straight rod part, the driving and driven crank rotates around the camshaft, and the adjusting rotation angle process will be stuck. It is not convenient to adjust the wear gap of the shoe group. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a self-adjusting drum brake for electric vehicle, which solves the problem that the gap between the shoe assembly and the wheel hub becomes larger after long-term wear of the shoe assembly of the existing brake, and the problems of untimely and inaccurate adjustment of the brake gap and heavy hand feeling.

[0007] In order to achieve the above purpose, the present application is realized by the following technical scheme:

[0008] The application discloses a self-adjusting drum brake for electric vehicles, which comprises a brake chamber shell assembly, a friction shoe assembly, a cam shaft and a rocker arm, the inside of the brake chamber shell assembly is provided with the friction shoe assembly, the first end of the friction shoe assembly is rotatably installed on the fixed core rotating shaft of the brake chamber shell assembly, the second end is abutted against the cam portion of one end of the cam shaft, the cam body of the other end of the cam shaft is pivotally connected in the through hole of the brake chamber shell assembly, the rocker arm and the end portion of the cam body are detachably fixed outside the brake chamber shell assembly, the outside of the cam body is provided with a tooth-shaped structure, and the self-adjusting drum brake further comprises a poking mechanism and a self-adjusting mechanism, the poking mechanism pokes the cam shaft to rotate, the self-adjusting mechanism keeps in place and moves by the same angle relative to the poking mechanism, the reset spring is further arranged between the poking mechanism and the brake chamber shell assembly, the poking mechanism is reset under the action of the reset spring, and the cam shaft keeps an angle under the adjustment of the self-adjusting mechanism.

[0009] Further improvement lies in that the poking mechanism is a first ratchet device arranged on the rocker arm, the self-adjusting mechanism is a second ratchet device arranged on the brake chamber shell assembly, the first ratchet device comprises a first ratchet and a first compression spring, the second ratchet device comprises a second ratchet and a second compression spring, and the first ratchet and the second ratchet are respectively matched with the tooth-shaped structure; one end of the rocker arm is provided with a brake cable connecting portion, the other end is provided with a fixing hole, a first special-shaped groove is arranged in the inside of the fixing hole, the opening of one side of the first special-shaped groove is communicated with the fixing hole, one side of the brake chamber shell assembly is provided with a second special-shaped groove, and the opening of one side of the second special-shaped groove is communicated with the through hole; the first ratchet device is installed in the first special-shaped groove, and the second ratchet device is installed in the second special-shaped groove.

[0010] Further improvement lies in that the first ratchet and the second ratchet are respectively provided with ratchet teeth and a positioning pivot, the ratchet teeth are engaged with the tooth-shaped structure, the first special-shaped groove and the second special-shaped groove are provided with a positioning hole groove structure, and the positioning pivot is matched with the positioning hole groove structure.

[0011] Further improvement lies in that the first side surface of the first ratchet is attached to the side surface of the first special-shaped groove, the second side surface of the first ratchet is provided with a compression spring limiting portion, the first compression spring is abutted between the compression spring limiting portion and the first special-shaped groove, and the second ratchet is provided with a first side surface, a second side surface and a compression spring limiting portion.

[0012] Further improvement lies in that the first special-shaped groove is further provided with a first baffle, the first baffle is matched to cover the first special-shaped groove, and the second special-shaped groove is matched to cover a second baffle.

[0013] Further improvement lies in that the first ratchet and the second ratchet are arranged as upper and lower mirror image symmetrical structures along the cam shaft.

[0014] Further improvement lies in that the cam body is arranged in two-section tooth shape structure, the middle section is cylindrical structure, and the end is provided with a circumferential annular groove, and the annular groove is provided with a buckle member for buckling connection with the rocker arm.

[0015] Further improvement lies in that the lug structure is further provided on the brake chamber housing assembly, and a brake cable installation structure is arranged on the lug structure and connected with the brake cable connecting part of the rocker arm to form a manual wear gap adjusting structure.

[0016] The present application has the following advantages:

[0017] The combination of the shifting mechanism and the self-adjusting mechanism, the interaction between the return spring and the cam shaft makes the cam shaft not reset after the wear of the friction shoe block assembly, and the rocker arm is reset, which is used to compensate the gap between the friction shoe block assembly and the brake drum after the wear of the friction shoe block assembly, so that the gap is kept constant, the brake rocker is always in an effective and controllable range, the normal gap between the friction shoe block assembly and the wheel hub is always kept, the automatic adjustment is realized through the forward direction brake after the wear of the friction shoe block assembly, the wear gap adjusting is flexible, fast, accurate and timely, and the safety of the rider is ensured, and the application is more humanized.

[0018] The shifting mechanism and the self-adjusting mechanism are arranged on the ratchet device on the rocker arm and the brake chamber housing assembly and the toothed structure on the cam shaft, so that the adjusting process is flexible, fast, accurate and timely. The ratchet device is composed of a ratchet and a compression spring matched in an open special-shaped groove, has a stable structure, vibration and buffering effect, keeps the gap constant, and can effectively prevent the jamming caused by the too small gap adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a self-adjusting drum brake structure diagram for electric vehicle.

[0020] Figure 2 It is a sectional view of a self-adjusting drum brake for electric vehicle.

[0021] Figure 3 It is an exploded view of a self-adjusting drum brake for electric vehicle.

[0022] Figure 4 It is a position diagram of a shifting mechanism and a self-adjusting mechanism of a self-adjusting drum brake for electric vehicle.

[0023] Figure 5 It is a structure diagram of a shifting mechanism and a self-adjusting mechanism of a self-adjusting drum brake for electric vehicle.

[0024] Figure 6 It is a rocker arm structure diagram of a self-adjusting drum brake for electric vehicle.

[0025] Figure 7It is a kind of self-regulating drum brake shell structure diagram of electric vehicle.

[0026] Figure 8 It is a kind of self-regulating drum brake camshaft structure diagram of electric vehicle.

[0027] Figure identification: brake chamber shell assembly 10, friction block assembly 20, camshaft 30, rocker arm 40, actuating mechanism 50, self-regulating mechanism 60, return spring 70, buckle 80, fixed core shaft 11, through hole 12, second special-shaped groove 13, second baffle 14, lug structure 15, cam portion 31, cam body 32, toothed structure 33, annular groove 34, brake cable connection portion 41, fixing hole 42, first special-shaped groove 43, first baffle 44, first ratchet device 51, first ratchet, first compression spring 53, first side 521, second side 522, compression spring limiting portion 523, second ratchet device 61, second ratchet, second compression spring 63, first side 621, second side 622, compression spring limiting portion 623, ratchet 524, 624, positioning pivot 520, 620, positioning hole groove structure 430, 130. DETAILED DESCRIPTION

[0028] In order to deepen the understanding of the present application, the present application will be further described in detail below in conjunction with the drawings, and the present embodiment is only used to explain the present application, and does not constitute the limitation to the protection scope of the present application. Obviously, the described embodiment is only a part of the embodiment of the present application, rather than all the embodiments. Based on the embodiment in the present application, all other embodiments obtained by the person skilled in the art without making creative labor belong to the protection scope of the present application.

[0029] The present application will be further described in detail below in conjunction with the drawings and the embodiment.

[0030] As Figures 1-3An embodiment of self-adjusting drum brake for electric vehicle is given, which comprises brake chamber assembly 10, friction shoe assembly 20, cam shaft 30 and rocker arm 40. The friction shoe assembly 20 is arranged inside the brake chamber assembly 10. The first end of the friction shoe assembly 20 is rotatably mounted on the fixed core rotating shaft 11 of the brake chamber assembly 10. The second end of the friction shoe assembly 20 abuts against the cam portion 31 at one end of the cam shaft 30. The other end of the cam shaft 30 is pivotally connected to the cam body 32 in the through hole 12 of the brake chamber assembly 10. The rocker arm 40 is detachably fixed to the outside of the brake chamber assembly 10 at the end of the cam body 32. The cam body 32 is provided with a toothed structure 33 on the outside. The self-adjusting drum brake further comprises a poking mechanism 50 and a self-adjusting mechanism 60. The poking mechanism 50 pokes the cam shaft 30 to rotate. The self-adjusting mechanism 60 remains in place and slides by the same angle relative to the poking mechanism 50. The poking mechanism 50 is further provided with a return spring 70 between the poking mechanism 50 and the brake chamber assembly 10. The poking mechanism 50 is reset under the action of the return spring 70. The cam shaft 30 is kept at an angle under the adjustment of the self-adjusting mechanism 60. Under the combined action of the poking mechanism, the self-adjusting mechanism and the cam shaft with such a structure, the friction shoe assembly 20 is kept slightly open. The brake gap caused by the wear of the friction shoe assembly 20 is compensated and adjusted, so that the adjustment-free function is realized without manual adjustment.

[0031] As Figure 4 , 5 shown, the poking mechanism 50 is a first ratchet device 51 arranged on the rocker arm 40. The first ratchet device 51 comprises a first ratchet and a first compression spring 53. The self-adjusting mechanism 60 is a second ratchet device 61 arranged on the brake chamber assembly 10. The second ratchet device 61 comprises a second ratchet and a second compression spring 63. The first ratchet and the second ratchet are respectively provided with ratchet teeth 524 and 624 which are engaged with the toothed structure 33. One end of the rocker arm 40 is provided with a brake cable connecting portion 41. The other end of the rocker arm 40 is provided with a fixing hole 42. A first special-shaped groove 43 is arranged inside the fixing hole 42. The first special-shaped groove 43 is open on one side and communicates with the fixing hole 42. The first ratchet device 51 is arranged in the first special-shaped groove 43. The ratchet teeth 524 pass through the opening and are engaged with the toothed structure 33 of the cam shaft 30. One side of the brake chamber assembly 10 is provided with a second special-shaped groove 13. The second special-shaped groove 13 is open on one side and communicates with the through hole 12. The second ratchet device 61 is arranged in the second special-shaped groove 13.

[0032] By employing the interaction between the combined ratchet mechanism, torsion spring, and the toothed structure of the camshaft, the camshaft 30 is rotated by an angle, and the friction shoe assembly 20 is opened for braking. The rocker arm then returns to its original position under the action of the return spring. However, after the friction shoe assembly wears down, the camshaft does not return to its original position under the action of the self-adjusting mechanism, thus achieving self-adjustment compensation for the increased braking clearance caused by wear of the shoe assembly. One side of the second irregular groove 13 communicates with the through hole 12, and one side of the first irregular groove 43 communicates with the fixing hole 42; this ensures reliable meshing between the ratchet installed therein and the toothed structure of the camshaft.

[0033] like Figures 4-7 The first and second ratchet wheels shown are respectively provided with positioning pivots 520 and 620. Positioning hole and slot structures 430 and 130 are provided within the first irregular groove 43 and the second irregular groove 13, respectively. The positioning pivots 520 and 620 are adapted to the positioning hole and slot structures 430 and 130. The first side 521 of the first ratchet wheel is in contact with one side of the first irregular groove 43. The second side 522 of the first ratchet wheel is provided with a compression spring limiting part 523. The first compression spring 53 abuts between the compression spring limiting part 523 and the other side of the first irregular groove 43. The second ratchet wheel has a first side 621, a second side 622, and a compression spring limiting part 623 corresponding to the first ratchet wheel. The first and second ratchet wheels are configured as mirror images of each other along the camshaft 30.

[0034] This ensures a secure connection between the ratchet and the groove, and reliable braking and resetting. During braking, the first compression spring abuts against the compression spring limiting part 523 and the other side of the first groove 43. The first side 521 of the first ratchet fits against one side of the first groove 43. The ratchet 520, driven by the rocker arm 40, moves the tooth structure 33 of the camshaft 30, causing the camshaft 30 to rotate. At this time, the first compression spring 53 provides stability and support for the ratchet 52. The second ratchet is installed in the second groove 13 of the brake box housing assembly 10, symmetrically positioned above and below the first ratchet. During braking, since the rocker arm 40 drives the camshaft 30 to rotate together, and the brake box housing assembly 10 remains stationary, the second ratchet needs to slide relative to the camshaft 30 to maintain its original position. At this time, the second compression spring 63 provides vibration and sliding action for the second ratchet.

[0035] When the braking is over, the rocker arm 40 is reset under the counterforce of the reset spring 70, the first ratchet wheel is reset under the action of the first compression spring 53 and the reset spring 70, at this time, the first compression spring 53 plays a role of vibrating the ratchet wheel 52, the second ratchet wheel is engaged with the toothed structure of the cam shaft 30 after being combined with one side of the second special-shaped groove 13 after rotating a small angle when the rocker arm 40 is reset, thereby preventing the cam shaft 30 from rotating and resetting, so that the wear gap of the friction shoe assembly 20 caused by braking is compensated, the second compression spring 63 plays a role of buffering when the second ratchet wheel 63 is engaged again after rotating a small angle when the rocker arm is reset, that is, when the wear gap is too small to be one tooth pitch, the ratchet wheel is not vibrated but buffered through the compression spring, so that the braking gap is kept constant, and the jamming caused by the too small gap adjustment can be effectively prevented, therefore, the structure size of the second ratchet wheel, the second compression spring 63 and the second special-shaped groove 13 is set as required.

[0036] As shown in Figure 3 : the first special-shaped groove 43 is further provided with a first baffle 44, the first baffle 44 is adapted to cover the first special-shaped groove 43, and the second special-shaped groove 13 is adapted to cover the second baffle 14. In this way, the structure is more firm and reliable, and is not easy to fall apart.

[0037] As shown in Figure 8 : the cam body 32 is provided with two upper and lower toothed structures 33, a middle section is a cylindrical structure, and the end is provided with a circumferential annular groove 34, the annular groove 34 is provided with a buckle 80 for buckling connection with the rocker arm 40; the brake is firmly and reliably connected as a whole, and is convenient to assemble and maintain.

[0038] The two toothed structures 33 can be provided as opposite direction ratchets, which are adapted to the ratchets 524 and 624 of the first ratchet wheel and the second ratchet wheel; in this way, the structure is more convenient and reasonable when the ratchets are vibrated and engaged and clamped, and the transmission is reliable. Alternatively, the cam body 32 can be mainly provided as a full tooth structure, the full tooth is divided into two opposite direction ratchets, or the ratchets 524 and 624 of the first ratchet wheel and the second ratchet wheel are provided as opposite direction ratchets and are used in cooperation with the toothed structure of the same direction on the cam shaft.

[0039] More preferably, the brake chamber housing assembly 10 is further provided with a lug structure 15, the lug structure 15 is provided with a brake cable installation structure and a brake cable connecting part 41 of the rocker arm 40 to form a manual wear gap adjustment structure. In this way, the manual gap adjustment and the automatic gap adjustment are combined to adjust, the product adjustment performance is more convenient and superior, the safety of the rider is ensured, and the product is more humanized and rationalized.

[0040] The action principle of the application is as follows:

[0041] Braking: the rocker arm 40 is pulled, the first side surface 521 of the first ratchet wheel is in contact with one side surface of the first special-shaped hole 43, the external toothed structure 33 on the camshaft 30 is engaged with the ratchet teeth 524 on the first ratchet wheel under force, the camshaft 30 is driven to rotate, the second ratchet wheel rotates with the camshaft 30 under the action of the second compression spring 63, the sliding teeth of the second ratchet wheel do not move relative to the brake chamber housing assembly 10, and the rotation of the camshaft 30 is not affected, so that the friction shoe block assembly 20 rotates with the camshaft 30 and is stretched, and the brake effect is realized;

[0042] After braking: the rocker arm 40 is released, the rocker arm 40 is reset under the action of the reset spring 70, at this time, the second side surface 522 of the first ratchet wheel is in contact with the first compression spring 53, the first ratchet wheel rotates under the action of the first compression spring 53, the rocker arm 40 is reset, and the rocker arm 40 returns to the position before braking; the first side surface 621 of the second ratchet wheel is in contact with the side surface of the second special-shaped hole 13 of the brake chamber housing assembly 10, the second ratchet teeth 624 are engaged with the toothed structure 33 of the camshaft 30, the camshaft 30 is prevented from resetting, the camshaft 30 is not reset, the shoe block is in a stretched state at an angle, and the brake gap caused by the wear of the friction shoe block assembly 20 is compensated and adjusted;

[0043] Such reciprocation: after the next shoe block wear, the drum brake operates according to the same principle, the rocker arm is automatically reset, the shoe block is always stretched, and the maintenance-free purpose is realized.

[0044] The embodiments of the present application disclose the preferred embodiments, but are not limited thereto, and those skilled in the art can easily understand the spirit of the present application according to the above-mentioned embodiments, and make different inferences and changes, as long as they do not deviate from the spirit of the present application, and are within the protection scope of the present application.

Claims

1. A self-adjusting drum brake for an electric vehicle, comprising a brake box housing assembly (10), a friction shoe assembly (20), a camshaft (30), and a rocker arm (40), wherein the friction shoe assembly (20) is provided inside the brake box housing assembly (10), the first end of the friction shoe assembly (20) is rotatably mounted on the centering shaft (11) of the brake box housing assembly (10), and the second end abuts against the cam portion (31) at one end of the camshaft (30), the other end of the camshaft (30) is pivotally connected to the cam body (32) in the through hole (12) of the brake box housing assembly (10), the rocker arm (40) is detachably fixed to the end of the cam body (32) on the outside of the brake box housing assembly (10), and the cam body (32) is provided with a toothed structure (33) on the outside, characterized in that: It also includes a toggle mechanism (50) and a self-adjusting mechanism (60). The toggle mechanism (50) toggle the camshaft (30) to rotate. The self-adjusting mechanism (60) remains in place and slides at the same angle relative to the toggle mechanism (50). A return spring (70) is also provided between the toggle mechanism (50) and the gate housing assembly (10). The toggle mechanism (50) is reset under the action of the return spring (70). The camshaft (30) is maintained at an angle under the adjustment of the self-adjusting mechanism (60). The actuating mechanism (50) is a first ratchet device (51) mounted on the rocker arm (40), and the self-adjusting mechanism (60) is a second ratchet device (61) mounted on the brake box housing assembly (10). The first ratchet device (51) includes a first ratchet and a first compression spring (53), and the second ratchet device (61) includes a second ratchet and a second compression spring (63). The first ratchet and the second ratchet are respectively adapted to the toothed structure (33); one end of the rocker arm (40) is provided with a brake cable connection part ( 41), and a fixing hole (42) is provided at the other end. A first irregular groove (43) is provided inside the fixing hole (42). One side of the first irregular groove (43) is connected to the fixing hole (42). A second irregular groove (13) is provided on one side of the gate box housing assembly (10). One side of the second irregular groove (13) is connected to the through hole (12). The first ratchet device (51) is installed in the first irregular groove (43), and the second ratchet device (61) is installed in the second irregular groove (13). The first ratchet and the second ratchet are respectively provided with ratchet teeth (524, 624) and positioning pivots (520, 620). The ratchet teeth (524, 624) mesh with the tooth structure (33). The first irregular groove (43) and the second irregular groove (13) are provided with positioning hole groove structures (430, 130). The positioning pivots (520, 620) are adapted to the positioning hole groove structures (430, 130). The first ratchet has a first side surface (521) that fits against one side of the first irregular groove (43). The second side surface (522) of the first ratchet is provided with a compression spring limiting part (523). The first compression spring (53) abuts between the compression spring limiting part (523) and the first irregular groove (43). The second ratchet is provided with a first side surface (621), a second side surface (622) and a compression spring limiting part (623).

2. The self-adjusting drum brake for an electric vehicle according to claim 1, characterized in that: The first irregular groove (43) is also provided with a first baffle (44), the first baffle (44) is adapted to cover the first irregular groove (43), and the second irregular groove (13) is adapted to cover the second baffle (14).

3. The self-adjusting drum brake for an electric vehicle according to claim 1, characterized in that: The first ratchet and the second ratchet are configured as mirror images of each other along the camshaft (30).

4. The self-adjusting drum brake for an electric vehicle according to claim 1, characterized in that: The cam body (32) is configured as a toothed structure with two upper and lower sections, a cylindrical structure in the middle section, and a circumferential annular groove (34) at the end. The annular groove (34) is provided with a buckle (80) to buckle and connect with the rocker arm (40).

5. The self-adjusting drum brake for an electric vehicle according to claim 1, characterized in that: The gate box housing assembly (10) is also provided with a lug structure (15), and the lug structure (15) is provided with a brake cable threading structure and a brake cable connection part (41) of the rocker arm (40) to form a manual wear gap adjustment structure.

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