Self-adjusting drum brakes for electric vehicles

Abstract

The present invention discloses an automatic adjustment drum brake for electric vehicles, which includes a brake chamber housing part, a friction shoe part, a camshaft, a rocker arm, a toggle mechanism, and an automatic adjustment mechanism. A friction shoe part is provided inside the brake chamber housing part, a tooth structure is provided outside the cam body, the toggle mechanism rotates the camshaft, the automatic adjustment mechanism stays in its original position, and slides and rotates at the same angle relative to the toggle mechanism. A reset spring is provided between the toggle mechanism and the brake chamber housing part, the toggle mechanism returns under the action of the reset spring, and the camshaft maintains its angle by adjusting the automatic adjustment mechanism. The toggle mechanism and the automatic adjustment mechanism are adjusted to fit the tooth structure provided outside the cam body by a ratchet wheel. This solves the problem that the gap between the shoe part and the wheel hub of the existing brake becomes large due to long-term wear, and the brake gap adjustment is not timely and accurate, and the hand feels heavy.

Description

[Technical Field]

[0001] The present invention relates to the field of brakes for automobiles or electric vehicles, and in particular to self-adjusting drum brakes for electric vehicles. [Background technology]

[0002] In drum brakes, the rotation of the rocker arm rotates the camshaft, driving the shoes on both sides to open and press against the brake drum, preventing the wheel from rotating due to friction between the brake drum and the shoes. Over time, the brake wire becomes longer due to its elasticity, and as the shoes wear over time, the gap between the wire and the wheel hub increases, usually resulting in reduced braking performance and brake failure. While manual adjustment of the brake wire screws is often required to tighten the brake wire or replace the brakes, it is difficult to ensure timeliness and accuracy when manually adjusting the brake gap.

[0003] Automatic brake gap adjustment devices are widely used in the automotive field, but in the prior art, drum brakes are rarely used in electric vehicles, tricycles, and motorcycles.

[0004] For example, Chinese Patent No. CN106050999B discloses a crank device with an automatic brake gap adjustment function. In the crank device, a drive arm and a driven arm form a crank, and both the driven arm and the drive arm are attached to a camshaft. The driven arm is fixedly connected to the camshaft, and the drive arm is movably connected to the camshaft. The drive arm is provided with a ratchet mechanism, a threaded hole is provided in the center of a ratchet wheel, and the driven arm is provided with an adjustment screw that is threaded into the threaded hole in the ratchet wheel. The ratchet mechanism, the adjustment screw, and the position limiting block on the hub brake cover are used in combination to automatically adjust the brake gap of the hub brake. When the drive arm moves to a set angle, the tip of the ratchet pawl lever on the drive arm contacts the position limiting block, causing the ratchet pawl lever to rotate and move the ratchet pawl one tooth on the ratchet wheel.

[0005] The ratchet device designed for this type of drive-driven crank is complex and heavy, and requires adjustment in combination with a position limiting block, resulting in high braking resistance and a heavy feel. Furthermore, the adjusting screw is a straight rod-shaped part, and the rotation of the drive-driven crank around the camshaft is a circular motion, which can cause a stuck phenomenon when adjusting the rotation angle, making it inconvenient to adjust the wear gap of the shoe group later. Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the shortcomings of the prior art, the present invention provides a self-adjusting drum brake for electric vehicles, which solves the problem that the gap between the shoe parts and the wheel hub of the existing brakes becomes large due to long-term wear, which causes the brake gap adjustment to be inaccurate and timely, resulting in a heavy feel. [Means for solving the problem]

[0007] The above technical object of the present invention is achieved by the following technical means.

[0008] The present invention provides a self-adjusting drum brake for electric vehicles, including a brake chamber housing component, a friction shoe component, a camshaft, and a rocker arm. A friction shoe component is provided inside the brake chamber housing component, with a first end of the friction shoe component rotatably attached to a centering shaft of the brake chamber housing component and a second end abutting a cam portion at one end of the camshaft. A cam body at the other end of the camshaft is pivotally mounted within a through-hole in the brake chamber housing component. The rocker arm and the ends of the cam body are detachably fixed to the outside of the brake chamber housing component, and a toothed structure is provided on the outside of the cam body. The self-adjusting drum brake for electric vehicles further includes a toggle mechanism and an automatic adjustment mechanism. The toggle mechanism rotates the camshaft, and the automatic adjustment mechanism remains in its original position and slides and rotates at the same angle relative to the toggle mechanism. A reset spring is provided between the toggle mechanism and the brake chamber housing component, and the toggle mechanism returns to its original position under the action of the reset spring, allowing the camshaft to maintain its angle through adjustment by the automatic adjustment mechanism.

[0009] In a further improvement, the toggle mechanism is a first ratchet device provided on the rocker arm, and the automatic adjustment mechanism is a second ratchet device provided on the brake chamber housing component, the first ratchet device including a first ratchet wheel and a first compression spring, and the second ratchet device including a second ratchet wheel and a second compression spring, the first ratchet wheel and the second ratchet wheel each being matched with a toothed structure. A brake wire connection portion is provided on one end of the rocker arm, and a fixing hole is provided on the other end, a first profile groove is provided inside the fixing hole, an opening on one side of the first profile groove communicates with the fixing hole, and a second profile groove is provided on one side of the brake chamber housing component, an opening on one side of the second profile groove communicates with a through-hole. The first ratchet device is installed in the first profile groove, and the second ratchet device is installed in the second profile groove.

[0010] As a further improvement, the first ratchet wheel and the second ratchet wheel are respectively provided with ratchet teeth and a positioning pivot, the ratchet teeth are meshed with tooth-like structures, the first profile groove and the second profile groove are provided with positioning hole groove structures, and the positioning pivot is matched with the positioning hole groove structures.

[0011] As a further improvement, the first side of the first ratchet wheel is in close contact with one side of the first deformed groove, a compression spring limiting portion is provided on the second side of the first ratchet wheel, the first compression spring abuts between the compression spring limiting portion and the first deformed groove, and the second ratchet wheel is provided with a first side, a second side, and a compression spring limiting portion.

[0012] As a further improvement, the first profiled groove is further provided with a first baffle, the first baffle being adapted to cover the first profiled groove, and the second profiled groove being covered by a second baffle.

[0013] As a further improvement, the first ratchet wheel and the second ratchet wheel are arranged in a mirror-symmetrical structure above and below the camshaft.

[0014] As a further improvement, the cam body has a two-stage tooth structure, an upper and lower, a cylindrical middle section, a circumferential annular groove at the end, and a locking device that engages with the rocker arm is provided within the annular groove.

[0015] As a further improvement, the brake chamber housing part is further provided with a lug structure, and the lug structure is provided with a brake wire mounting structure, which, together with the wire holding structure of the rocker arm, forms a manual wear gap adjustment structure. [Effects of the Invention]

[0016] The present invention has the following beneficial effects.

[0017] 1. The combined toggle mechanism and automatic adjustment mechanism, along with the interaction between the reset spring and the camshaft, prevent the camshaft from resetting after the friction shoe wears. Meanwhile, the rocker arm resets to compensate for the gap between the friction shoe and the brake drum after it wears, keeping the gap constant and ensuring that the brake rocker arm is always within an effective and controllable range, always maintaining the normal gap between the friction shoe and the wheel hub. After the friction shoe wears, it can be automatically adjusted by applying the brakes in the forward direction. The wear gap adjustment is flexible, fast, and accurate, ensuring rider safety and making it easier to use.

[0018] 2. The toggle mechanism and automatic adjustment mechanism are installed on the rocker arm and match the ratchet device of the brake chamber housing part and the tooth structure of the camshaft, making the brake adjustment process flexible, fast, accurate, and timely. The ratchet device consists of a ratchet wheel and a compression spring fitted into an open groove, making the structure strong and stable and providing vibration and buffering functions. Maintaining a constant gap can effectively prevent sticking caused by too small a gap. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram of the structure of an automatically adjusting drum brake for an electric vehicle. [Figure 2] 1 is a cross-sectional view of a self-adjusting drum brake for an electric vehicle. [Figure 3] 1 is an exploded schematic view of a self-adjusting drum brake for an electric vehicle. [Figure 4] FIG. 1 is a schematic diagram showing the positions of a toggle mechanism and an automatic adjustment mechanism of an automatic adjustment drum brake for an electric vehicle. [Figure 5] 1 is a structural schematic diagram of a toggle mechanism and an automatic adjustment mechanism of an automatic adjustment drum brake for an electric vehicle. [Figure 6] FIG. 1 is a structural schematic diagram of a rocker arm of an automatically adjusting drum brake for an electric vehicle. [Figure 7]1 is a structural schematic diagram of a brake chamber housing of a self-adjusting drum brake for an electric vehicle. [Figure 8] FIG. 1 is a structural schematic diagram of a camshaft of an automatically adjusting drum brake for an electric vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0020] In order to better understand the present invention, the present invention will be described in more detail below with reference to the accompanying drawings. However, this embodiment is only used to explain the present invention and does not limit the protection scope of the present invention. It is clear that the described embodiments are only a part of the embodiments of the present invention, and are not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] The present invention will now be described in more detail with reference to the accompanying drawings and embodiments.

[0022] 1 to 3 show one embodiment of a self-adjusting drum brake for an electric vehicle. The self-adjusting drum brake for an electric vehicle includes a brake chamber housing component 10, a friction shoe component 20, a camshaft 30, and a rocker arm 40. The friction shoe component 20 is provided inside the brake chamber housing component 10. A first end of the friction shoe component 20 is rotatably attached to a centering shaft 11 of the brake chamber housing component 10. A second end of the friction shoe component 20 abuts against a cam portion 31 at one end of the camshaft 30. A cam body 32 at the other end of the camshaft 30 is pivotally attached within a through-hole 12 of the brake chamber housing component 10. The rocker arm 40 and the ends of the cam body 32 are detachably fixed to the outside of the brake chamber housing component 10. A toothed structure 33 is provided on the outside of the cam body 32. The self-adjusting drum brake for an electric vehicle further includes a toggle mechanism 50 and an automatic adjustment mechanism 60. The toggle mechanism 50 rotates the camshaft 30, and the automatic adjustment mechanism 60 remains in its original position and slides and rotates at the same angle relative to the toggle mechanism 50, a reset spring 70 is provided between the toggle mechanism 50 and the brake chamber housing component 10, the toggle mechanism 50 returns to its original position under the action of the reset spring 70, and the camshaft 30 maintains its angle through adjustment by the automatic adjustment mechanism 60. By combining a toggle mechanism, automatic adjustment mechanism, and camshaft of this structure, the friction shoe component 20 is maintained in a slightly open state, and brake clearance caused by wear of the friction shoe component 20 is compensated for and adjusted, thereby realizing an adjust-free function that does not require manual adjustment.

[0023] As shown in Figures 4 and 5, the toggle mechanism 50 is a first ratchet device 51 provided on the rocker arm 40, and the first ratchet device 51 includes a first ratchet wheel 52 and a first compression spring 53, and the automatic adjustment mechanism 60 is a second ratchet device 61 provided on the brake chamber housing part 10, and the second ratchet device 61 includes a second ratchet wheel 62 and a second compression spring 63, and the first ratchet wheel 52 and the second ratchet wheel 62 are respectively provided with ratchet teeth 524, 624 that mesh with the toothed structure 33. A brake wire connection portion 41 is provided at one end of the rocker arm 40, and a fixing hole 42 is provided at the other end. A first profile groove 43 is provided inside the fixing hole 42, and one opening of the first profile groove 43 communicates with the fixing hole 42. The first ratchet device 51 is installed in the first profile groove 43, and ratchet teeth 524 pass through the opening and engage with the toothed structure 33 of the camshaft 30. A second profile groove 13 is provided on one side of the brake chamber housing part 10, and one opening of the second profile groove 13 communicates with the through hole 12. The second ratchet device 61 is installed in the second profile groove 13.

[0024] By combining the ratchet device, torsion spring, and toothed structure of the camshaft, when the camshaft 30 is rotated through a certain angle and the friction shoe assemblies 20 are spread apart to apply the brake, the rocker arm returns to its original position under the action of the reset spring. When the friction shoe assemblies wear, the camshaft does not return to its original position under the action of the automatic adjustment mechanism, and the brake gap increased due to the wear of the shoe assemblies is automatically adjusted to compensate. One opening of the second profile groove 13 communicates with the through hole 12, and one opening of the first profile groove 43 communicates with the fixing hole 42. This allows the ratchet wheel installed there to reliably engage with the toothed structure of the camshaft.

[0025] 4 to 7, the first ratchet wheel 52 and the second ratchet wheel 62 are provided with positioning pivots 520 and 620, respectively. Positioning hole groove structures 430 and 130 are provided in the first deformed groove 43 and the second deformed groove 13, respectively. The positioning pivots 520 and 620 are fitted to the positioning hole groove structures 430 and 130. A first side surface 521 of the first ratchet wheel 52 is in close contact with one side surface of the first deformed groove 43, and a compression spring limiting portion 523 is provided on a second side surface 522 of the first ratchet wheel 52. The first compression spring 53 abuts between the compression spring limiting portion 523 and the other side surface of the first deformed groove 43. The second ratchet wheel 62 is provided with a first side surface 621, a second side surface 622, and a compression spring limiting portion 623 corresponding to the first ratchet wheel 52. The first ratchet wheel 52 and the second ratchet wheel 62 are arranged vertically along the camshaft 30 in a mirror-symmetrical structure.

[0026] This ensures that the ratchet wheel is firmly connected to the profile groove, ensuring reliable braking and return. During braking, the first compression spring abuts between the compression spring limiting portion 523 and the other side of the first profile groove 43, and the first side 521 of the first ratchet wheel 52 is in close contact with one side of the first profile groove 43. The ratchet teeth 520 move the toothed structure 33 of the camshaft 30 through the rocker arm 40, causing the camshaft 30 to rotate. At this time, the first compression spring 53 serves to stably support the ratchet wheel 52. The second ratchet wheel 62 is installed in the second profile groove 13 of the brake chamber housing part 10 and is vertically symmetrical to the first ratchet wheel 52. During braking, the rocker arm 40 moves the camshaft 30 and rotates together, so the brake chamber housing part 10 does not move, and as a result, in order to maintain the second ratchet wheel 62 in its original position, the sliding teeth need to maintain their original positions relative to the camshaft 30. At this time, the second compression spring 63 plays a role in oscillating the sliding teeth of the second ratchet wheel 62.

[0027] When braking is completed, the rocker arm 40 returns due to the reaction force of the reset spring 70, and the sliding teeth of the first ratchet wheel 52 return due to the action of the first compression spring 53 and the reset spring 70. At this time, the first compression spring 53 serves to vibrate the sliding teeth of the first ratchet wheel 52. After the camshaft 30 rotates a small angle when the rocker arm 40 returns, the second ratchet wheel 62 comes into close contact with one side of the second profile groove 13 and then engages with the tooth structure of the camshaft 30 to prevent the camshaft 30 from rotating and returning, allowing the friction shoe assembly 20 to compensate for wear gaps caused by braking. Here, the second compression spring 63 provides a cushioning effect when the second ratchet wheel 62 engages after rotating a small angle when the rocker arm returns. In other words, if the wear gap is too small and is less than one tooth pitch, the teeth will not slip and will be cushioned by the compression spring, so the brake gap will be kept constant and sticking due to too small gap adjustment can be effectively prevented. Therefore, the structural dimensions of the second ratchet wheel 62, the second compression spring 63, and the second profile groove 13 here can be set as needed.

[0028] 3, the first profile groove 43 is further provided with a first baffle 44, the first baffle 44 is adapted to cover the first profile groove 43, and the second baffle 14 is adapted to cover the second profile groove 13. This design makes the structure stronger, more reliable, and less likely to collapse.

[0029] As shown in Figure 8, the cam body 32 has two stages of upper and lower tooth structures 33, the middle part is cylindrical, and the end part is provided with a circumferential annular groove 34, in which a locking member 80 is provided to engage with the rocker arm 40. The overall connection of the brake is strong and reliable, and assembly and maintenance are easy.

[0030] The two-stage tooth structure 33 can be provided as ratchet teeth in opposite directions that match the ratchet teeth 524, 624 of the first ratchet wheel 52 and the second ratchet wheel 62. This structure is more convenient and rational in terms of the transmission between the sliding teeth and the meshing teeth, and the transmission is more reliable. The cam body 32 can also be configured as a full-tooth structure divided into two stages of ratchet teeth in opposite directions. Alternatively, the ratchet teeth 524, 624 of the first ratchet wheel 52 and the second ratchet wheel can be arranged in opposite directions to cooperate with tooth structures in the same direction on the camshaft.

[0031] More preferably, the brake chamber housing part 10 is further provided with a lug structure 15, and the lug structure 15 is provided with a brake wire mounting structure, which, together with the wire retaining structure 41 of the rocker arm 40, forms a manual wear gap adjustment structure. This arrangement allows for a combination of manual and automatic gap adjustment, making the product's adjustment performance more convenient and excellent, ensuring rider safety and making it more user-friendly and rational.

[0032] The operating principle of the present invention is as follows.

[0033] During braking, when the rocker arm 40 is swung, the first side surface 521 of the first ratchet wheel 52 receives a force and comes into close contact with one side surface of the first profile groove 43, and the ratchet teeth 524 of the first ratchet wheel 52 engage with the toothed structure 33 of the camshaft 30, thereby driving the camshaft 30 to rotate. The second ratchet wheel 62 rotates together with the camshaft 30 under the action of the second compression spring 63, and the sliding teeth do not move relative to the brake chamber housing part 10 and do not affect the rotation of the camshaft 30. As the camshaft 30 rotates, the friction shoe part 20 is pushed apart, achieving a braking effect.

[0034] After braking is completed, the rocker arm 40 is released, and the rocker arm 40 returns to its original position due to the torsion spring 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, and the sliding teeth of the first ratchet wheel rotate and return together with the rocker arm 40 under the action of the first compression spring 53, returning the rocker arm 40 to its pre-brake position. The first side surface 621 of the second ratchet wheel 62 is in close contact with the side surface of the second profile groove 13 of the brake chamber housing component 10, and the second ratchet teeth 624 engage with the tooth structure 33 of the camshaft 30, preventing the camshaft 30 from returning. When the camshaft 30 does not return, the shoes remain open by a certain angle, thereby compensating for and adjusting the brake clearance of the friction shoe component 20 that has increased due to brake wear.

[0035] Repeating this process, after the shoe wears out the next time, the operating principle of the drum brake will be the same as above, the rocker arm will automatically return and the shoe will remain open, thus achieving the purpose of maintenance-free operation.

[0036] The present invention is not limited to the preferred embodiments disclosed above. Those skilled in the art can understand the spirit of the present invention based on the above embodiments and can easily make various extensions and modifications, but as long as they do not deviate from the spirit of the present invention, they shall all fall within the protection scope of the present invention. [Explanation of symbols]

[0037] Brake chamber housing part 10, friction shoe part 20, camshaft 30, rocker arm 40, toggle mechanism 50, automatic adjustment mechanism 60, reset spring 70, locking device 80, centering shaft 11, through hole 12, second profile groove 13, second baffle 14, lug structure 15, cam portion 31, cam body 32, tooth structure 33, annular groove 34, brake wire connection part 41, fixing hole 42, first profile groove 43, First baffle 44, first ratchet device 51, first ratchet wheel 52, first compression spring 53, first side surface 521, second side surface 522, compression spring limiting portion 523, second ratchet device 61, second ratchet wheel 62, second compression spring 63, first side surface 621, second side surface 622, compression spring limiting portion 623, ratchet teeth 524, 624, positioning pivots 520, 620, positioning hole groove structures 430, 130.

Claims

1. A self-adjusting drum brake for an electric vehicle, comprising a brake chamber housing component (10), a friction shoe component (20), a camshaft (30), and a rocker arm (40), A friction shoe component (20) is provided inside the brake chamber housing component (10), a first end of the friction shoe component (20) is rotatably attached to a centering shaft (11) of the brake chamber housing component (10), a second end of the friction shoe component (20) is in contact with a cam portion (31) at one end of a camshaft (30), a cam body (32) at the other end of the camshaft (30) is pivoted in a through hole (12) of the brake chamber housing component (10), the rocker arm (40) and the end of the cam body (32) are detachably fixed to the outside of the brake chamber housing component (10), and a toothed structure (33) is provided on the outside of the cam body (32), The self-adjusting drum brake for an electric vehicle further includes a toggle mechanism (50) and an automatic adjustment mechanism (60), wherein the toggle mechanism (50) rotates the camshaft (30), the automatic adjustment mechanism (60) remains in its original position and slides and rotates at the same angle relative to the toggle mechanism (50), a reset spring (70) is provided between the toggle mechanism (50) and the brake chamber housing part (10), the toggle mechanism (50) returns under the action of the reset spring (70), and the camshaft (30) maintains its angle by adjustment of the automatic adjustment mechanism (60), The cam body (32) has a two-stage tooth structure, with an upper and lower stage, a cylindrical structure in the middle, and a circumferential annular groove (34) at the end, and a locking member (80) that engages with the rocker arm (40) is provided within the annular groove (34). Self-adjusting drum brakes for electric vehicles.

2. The toggle mechanism (50) is a first ratchet device (51) provided on the rocker arm (40), and the automatic adjustment mechanism (60) is a second ratchet device (61) provided on the brake chamber housing part (10), the first ratchet device (51) including a first ratchet wheel (52) and a first compression spring (53), the second ratchet device (61) including a second ratchet wheel (62) and a second compression spring (63), and the first ratchet wheel (52) and the second ratchet wheel (62) are respectively fitted with toothed structures (33); A brake wire connection portion (41) is provided at one end of the rocker arm (40), a fixing hole (42) is provided at the other end, a first deformed groove (43) is provided inside the fixing hole (42), one opening of the first deformed groove (43) is connected to the fixing hole (42), a second deformed groove (13) is provided on one side of the brake chamber housing part (10), one opening of the second deformed groove (13) is connected to the through hole (12), 2. The self-adjusting drum brake for an electric vehicle according to claim 1, wherein the first ratchet device (51) is installed in a first profile groove (43) and the second ratchet device (61) is installed in a second profile groove (13).

3. 3. The self-adjusting drum brake for an electric vehicle according to claim 2, wherein the first ratchet wheel (52) and the second ratchet wheel (62) are provided with ratchet teeth (524), (624) and positioning pivots (520), (620), respectively, the ratchet teeth (524), (624) mesh with toothed structures (33), the first profile groove (43) and the second profile groove (13) are provided with positioning hole groove structures (430), (130), and the positioning pivots (520), (620) are fitted with the positioning hole groove structures (430), (130).

4. 3. The self-adjusting drum brake for an electric vehicle according to claim 2, wherein a first side surface (521) of the first ratchet wheel (52) is in close contact with one side surface of the first profile groove (43), a compression spring limiting portion (523) is provided on a second side surface (522) of the first ratchet wheel (52), the first compression spring (53) abuts between the compression spring limiting portion (523) and the first profile groove (43), and the second ratchet wheel (62) is provided with a first side surface (621), a second side surface (622), and a compression spring limiting portion (623).

5. 3. The self-adjusting drum brake for an electric vehicle according to claim 2, wherein a first baffle (44) is provided in the first profile groove (43), the first baffle (44) covers the first profile groove (43), and the second profile groove (13) is covered by a second baffle (14).

6. 3. The self-adjusting drum brake for an electric vehicle according to claim 2, wherein the first ratchet wheel (52) and the second ratchet wheel (62) are arranged in a mirror-symmetrical structure above and below along the camshaft (30).

7. 2. The self-adjusting drum brake for an electric vehicle according to claim 1, wherein the brake chamber housing component (10) is further provided with a lug structure (15), the lug structure (15) is provided with a brake wire mounting structure, and the brake wire mounting structure, together with a wire pressing structure (41) of the rocker arm (40), forms a manual wear gap adjustment structure.

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