Variable force arm brake

Abstract

The application discloses a variable-force-arm brake, relates to the technical field of brake devices, and aims to solve the problems of the existing hydraulic brake that cannot simultaneously consider labor saving and braking force and the poor locking reliability of a double-support-point brake. The brake comprises a brake shell, a piston assembly, a push rod assembly, a brake handle and a force arm switching component. The force arm switching component is provided with first and second rotation support point positions which are rotationally connected with the brake handle and the shell respectively. The brake handle is rotated at the first support point in the initial stage, and the short force arm quickly eliminates the idle stroke. The handle with the switching component is rotated at the second support point in the later stage, and the long force arm improves the braking force. Meanwhile, a groove constraint type pure geometric self-locking mechanism is adopted, and the initial stage second support point is completely self-locked without the need of elastic components. The application simultaneously considers the operation labor saving and the braking force output, reduces the kneading force, improves the braking response speed, has high locking stability, and completely eliminates the safety hazards of the locking mechanism failure.

Description

Technical Field

[0001] This invention relates to the field of braking device technology, specifically to a hydraulic brake operating device, and more particularly to a brake with a variable lever arm that dynamically changes during braking, taking into account both operating feel and braking force output. Background Technology

[0002] Brakes are the core braking components of bicycles, electric vehicles, motorcycles, and other personal transportation and sports vehicles. Their performance directly affects the feel of braking operation, response speed, braking force output efficiency, and driving safety. Currently, most mainstream hydraulic brakes adopt a structure design with a fixed single pivot point. By rotating the handle around the fixed pivot point, the push rod and piston move, establishing hydraulic pressure to achieve braking.

[0003] The existing fixed-pivot hydraulic brake lever has an irreconcilable core contradiction: the lever ratio of the brake lever is a fixed value. To achieve a smooth feel during the free stroke (the stroke before the piston eliminates the seal gap and establishes hydraulic pressure), a large lever ratio design is required, which provides sufficient braking force in the braking phase, but results in a longer free stroke and thus a slower braking response. To ensure a fast braking response, a small lever ratio design is required to quickly eliminate the free stroke, but this makes it difficult to squeeze the brake, resulting in a poor operating feel and easy hand fatigue during long rides.

[0004] To address the aforementioned issues, existing technologies have developed dual-rotation fulcrum structures for cable-operated disc brakes. However, their application scenarios are severely limited, and they cannot be adapted to hydraulic braking systems. Some improvements related to hydraulic brakes, while attempting to adjust the lever ratio, often suffer from defects such as unstable fulcrum switching transmission, lack of precise control over the switching nodes, and absence of state holding and anti-slip design. These defects result in insufficient braking precision, jerky operation, and even potential braking safety hazards.

[0005] Among other existing technologies, such as the patent with publication number CN201510830737A, the lever ratio adjustment is only achieved for cable-operated linkage brakes, with the core objective being the distribution of braking force between the front and rear wheels, which cannot be adapted to hydraulic braking systems; conventional hydraulic brake handles, such as the patent with publication number CN200820210270.5, are only fixed single-pivot structures without any design for dynamically switching the rotation pivot point, which cannot solve the industry pain point of "the inability to balance effort saving and braking force".

[0006] Furthermore, existing dual-pivot brake structures lack precise limiting and drive coordination during brake handle rotation, easily leading to problems such as pivot point movement and excessive transmission clearance. This makes it difficult to achieve smooth lever arm switching and balance the lightness of the idle stroke with the large braking force during braking. Therefore, there is an urgent need in this field for a brake solution that can adapt to hydraulic braking systems, achieve dynamic lever arm adjustment throughout the entire braking stroke, provide stable transmission, smooth switching, and ensure safety and reliability. Summary of the Invention

[0007] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the purpose of this invention is to propose a brake with a variable lever arm, achieving automatic and precise switching of the lever arm during the braking stroke, completely resolving the core contradiction of hydraulic brakes where "efficiency and braking force cannot be simultaneously achieved," while ensuring stable transmission, smooth switching, and safety and reliability, adapting to various hydraulic braking application scenarios.

[0008] The technical solution of this invention to solve its technical problem is: a brake with a variable lever arm, comprising: A brake housing having a piston chamber having a front opening and a rear opening; A piston assembly, which is movably disposed in the piston chamber; The push rod assembly is positioned at the rear end of the piston assembly, and the push rod assembly and the piston assembly form a transmission engagement. A brake handle is used to drive the push rod assembly, and the brake handle drives the piston assembly to move through the push rod assembly; A lever arm switching component has at least a first rotation fulcrum and a second rotation fulcrum; the first rotation fulcrum is connected to the brake handle through a first rotating shaft mechanism so that the brake handle and the lever arm switching component form a rotational engagement; the second rotation fulcrum is connected to the brake housing through a second rotating shaft mechanism so that the lever arm switching component and the brake housing form a rotational engagement. It also includes: A drive component is disposed on the brake handle, and the drive component moves together with the brake handle; In the initial stage of braking, there is a first stroke space between the drive component and the lever arm switching component. The drive component moves along the first stroke space and gradually approaches the lever arm switching component. During this process, the brake handle rotates around the first rotation fulcrum, and the lever arm switching component remains stationary relative to the brake housing. In the later stage of braking, the drive component contacts the lever arm switching component and forms a transmission engagement; during this process, the brake handle drives the lever arm switching component to rotate together around the second rotation fulcrum through the drive component. The brake handle has a gripping section. A first input force arm is formed between the first rotation fulcrum and the gripping section, and a second input force arm is formed between the second rotation fulcrum and the gripping section. The length of the first input force arm is less than the length of the second input force arm. Furthermore, the force arm switching component has a front section and a rear section. The driving component is in contact with the front section, and the guiding component is in contact with the rear section. Through the corresponding cooperation between the front section and the driving component, and between the rear section and the guiding component, precise driving and limiting during the rotation of the brake handle are achieved, preventing transmission deviation and ensuring the stability of the force arm switching.

[0009] Furthermore, it also includes a first guide mechanism, which includes a first groove formed on the brake housing and a second groove formed on the lever arm switching member. Both the first groove and the second groove have groove openings for the drive component to enter and exit, and the first groove and the second groove are arranged facing each other, forming an arc path L1 between the first groove and the second groove. In the initial braking phase, the drive component is located in the first groove and constrained by the first groove, so that the drive component moves along the initial arc path L1, and the initial arc path L1 is centered on the first rotation fulcrum; in the later braking phase, the drive component disengages from the first groove and is released from the constraint of the first groove, so that the drive component moves away from the initial arc path L1.

[0010] The groove structure can guide and limit the movement of the drive component. The first guide mechanism guides the path trajectory in the front section of the brake, preventing the drive component from deviating or getting stuck during the movement. At the same time, it provides space for the drive component, making the overall structure more compact and adaptable to different installation scenarios.

[0011] Furthermore, it also includes a second guiding mechanism, which includes a guide rib disposed on the brake housing, the guide rib extending from the first groove toward the side where the grip section is located; the guide rib has an arc-shaped guide surface to form a rear arc path L2; In the later stage of braking, the drive component contacts the force arc guide surface, so that the drive component moves along the arc path L2, and the arc path L2 is centered on the second rotation fulcrum; during this process, the brake handle drives the power arm switching component to rotate together with the drive component around the second rotation fulcrum.

[0012] The guide ribs can guide and limit the movement of the drive components. The second guide mechanism guides the path trajectory in the later stage of braking, preventing the drive components from deviating or jamming during movement.

[0013] Furthermore, it also includes a guide component disposed on the brake handle, the guide component moves together with the brake handle, and there is a second stroke space between the guide component and the lever arm switching component; The lever arm switching component has a front section and a rear section. The driving component is in contact with the front section, and the guiding component is in contact with the rear section through a reset assembly. The first and second rotation fulcrums are both located between the front and rear sections. During the squeezing of the brake handle, the guide component moves along the second stroke space and causes the reset component to gradually approach the lever arm switching component.

[0014] This layout allows the drive components, guide components, and two rotation fulcrums to form a reasonable force transmission path, ensuring smooth lever arm switching without transmission jamming when the brake lever is turned, while optimizing force transmission efficiency and reducing energy loss.

[0015] Furthermore, the driving component is a cylindrical rib disposed on the brake handle, and the guiding component is an arc-shaped rib disposed on the brake handle. The cylindrical rib structure can reduce the frictional force when the driving component contacts the lever arm switching component, making the transmission smoother; the arc-shaped rib can form a close contact with the rear section of the lever arm switching component, improving the limiting stability and avoiding gaps between the guiding component and the lever arm switching component, which would lead to a decrease in transmission accuracy.

[0016] Furthermore, the lever arm switching component also has a receiving cavity, and the reset assembly includes a first spring and a ball bearing disposed in the receiving cavity. The receiving cavity has a cavity opening facing the guide component. The first spring is disposed between the ball bearing and the inner wall of the receiving cavity, and the first spring applies an outward force to the ball bearing so that the ball bearing is always in contact with the guide component. The cooperation between the first spring and the ball bearing serves two purposes: first, it transmits force between the brake handle and the lever arm switching component; second, it eliminates gaps during the rotation of the brake handle, provides uniform damping force, avoids hard collisions when the guide component contacts the lever arm switching component, reduces the jerky feeling of operation, and guides the movement of the guide component, ensuring the linearity of lever arm switching.

[0017] It is important to emphasize that if the curved rib adopts a regular arc shape centered on the first rotation fulcrum, the reset assembly needs to be eccentrically positioned relative to the lever arm switching component. This is so that during the later stages of braking, the movement of the reset assembly relative to the lever arm switching component is differentiated, meaning the reset assembly can be compressed and contracted. Consequently, when the brake lever is released, the reset force of the reset assembly can promote the reset of the lever arm switching component.

[0018] Furthermore, the first rotating shaft mechanism includes a first rotating section and a first fixed section; the brake handle has a first rotating hole, and the first rotating section is connected to the first rotating hole and forms a rotating fit with the brake handle; the first rotating fulcrum has a first fixed hole, and the first fixed section is connected to the first fixed hole and forms a fixed fit with the lever arm switching component. This structure achieves a stable rotating fit between the brake handle and the lever arm switching component, ensures the positional accuracy of the first rotating fulcrum, avoids gaps in the fit after long-term use, and ensures the stability of the first input lever arm; The second rotating shaft mechanism includes a second rotating section and a second fixed section. A second rotating hole is provided at the second rotating fulcrum, and the second rotating section is connected to the second rotating hole to form a rotating fit with the lever arm switching component. The brake housing has a second fixed hole, and the second fixed section is connected to the second fixed hole to form a fixed fit with the brake housing. This structure achieves a stable rotating fit between the lever arm switching component and the brake housing, ensures the load-bearing strength of the second rotating fulcrum, meets the high torque requirements of the braking section, and ensures stable output of the second input lever arm.

[0019] Furthermore, the brake handle is connected to the push rod assembly via a rotary mechanism; the rotary mechanism includes a drive shaft, a rotary bearing, and a rotary connector; the brake handle has a bearing hole, and the rotary bearing is disposed in the bearing hole; the rotary connector includes a third fixed section, and the drive shaft has a third rotating section; the third rotating section is connected to the bearing inner hole of the rotary bearing and forms a rotary engagement with the rotary bearing; the drive shaft has a third fixed hole, and the third fixed section is connected to the third fixed hole and forms a fixed engagement with the drive shaft; the drive shaft has a drive hole, and the push rod assembly is connected to the drive hole and forms a fixed engagement with the drive shaft, thus the brake handle is connected to the push rod assembly via the rotary mechanism. This rotary mechanism, through the omnidirectional rotational engagement of the rotary bearing, can perfectly adapt to the rotational trajectory changes of two different rotational fulcrums, eliminate radial off-center load on the push rod assembly during lever arm switching, avoid uneven wear between the piston and piston chamber, and simultaneously convert the rotational motion of the brake handle into the linear pushing motion of the push rod, with no transmission loss, ensuring braking efficiency.

[0020] Furthermore, the piston assembly includes at least a piston body and a piston spring. The rear end of the piston body contacts the thrust assembly and forms a transmission engagement. The piston spring abuts against the inner wall of the piston chamber and the front end of the piston body. The piston spring acts on the piston body so that the piston body always has a tendency to move backward. Through the restoring force of the piston spring, in conjunction with the lever arm switching logic, the brake lever can be stably and automatically reset, ensuring that after the lever is released, all components can return to their initial state, preparing for the next braking.

[0021] The beneficial effects of this invention are as follows: First, this invention completely solves the industry pain point of hydraulic brakes where "effort saving and braking force cannot be balanced." Through automatic dynamic switching of the lever arm during the braking stroke, it achieves dynamic optimization of the leverage ratio: the initial idle stroke is centered on the first rotation fulcrum, with a shorter first input lever arm and a small leverage ratio design, making pinching easier and quickly eliminating idle stroke, thus improving the operating feel; the subsequent braking stroke is centered on the second rotation fulcrum, with a longer second input lever arm and a large leverage ratio design, resulting in a significant force amplification effect, greatly increasing braking force output and shortening braking distance. Actual testing shows that under the same braking force, the pinching force of this invention is significantly reduced compared to conventional fixed-fulcrum brakes, and the braking response speed is effectively improved.

[0022] II. The groove-constrained pure geometric self-locking unlocking mechanism completely solves the core problem of poor locking reliability in existing dual-pivot brakes. Through the constraint of the first groove on the drive component, complete self-locking of the second rotation pivot is achieved in the initial braking phase: the force exerted by the drive component on the sidewall of the groove always points towards the first rotation pivot, with no tangential component. Regardless of the clamping force, the multi-pivot linkage component will not rotate around the second rotation pivot. This self-locking mechanism requires no elastic components and is unaffected by friction, temperature, humidity, and wear, thus improving locking stability and completely eliminating the safety hazard of locking mechanism failure.

[0023] Third, the dual-guide mechanism full-stroke trajectory control technology achieves precise transmission throughout the braking process. The first guide mechanism, through the first and second grooves arranged in opposite directions, achieves pure geometric self-locking and precise guidance in the initial stage of braking, allowing the drive component to move stably along the initial arc path L1 without any radial movement. The second guide mechanism, through the arc-shaped guide surface of the guide rib, guides the drive component to move along the subsequent arc path L2 in the later stage of braking, ensuring that the lever arm switching component always rotates around the second rotation fulcrum, completely solving the problems of transmission offset and jamming in the later stage. The braking feel is linear and smooth throughout the entire stroke, without any jerking.

[0024] Fourth, through the coordinated operation of the drive component and the guide component, precise control and stable transmission of the lever arm switching are achieved. In the initial stage of braking, the drive component and the guide component move along the first and second stroke spaces respectively, ensuring that the brake handle rotates smoothly around the first rotation fulcrum. In the later stage of braking, both components simultaneously contact and transmit power to the lever arm switching component, driving the lever arm switching component to rotate around the second rotation fulcrum. This avoids transmission offset and spurring problems caused by a single drive or limit switch, ensuring smooth lever arm switching without any jerking.

[0025] Fifth, the dynamically adjustable lever arm technology is fully adapted to hydraulic braking scenarios, breaking through the limitation of existing dual-pivot structures that are only applicable to cable-operated brakes. It can be widely used in various hydraulically braked vehicles such as bicycles, electric vehicles, and motorcycles, greatly expanding its application scope. At the same time, the modular design of the lever arm switching component allows for precise optimization of lever arm parameters by adjusting the component size, without modifying the core structure of the brake housing and brake handle, significantly reducing mold opening and adaptation costs and facilitating mass production.

[0026] VI. Highly integrated structure, significantly reducing mass production costs. The self-locking, guiding, transmission, and reset functions are integrated into the cooperation between the drive component, guide component, groove, and guide rib. There is no need to set up separate locking, unlocking, and linkage mechanisms. The number of parts is reduced, the assembly process is simplified, and the processing technology is simple. The groove and guide rib can be formed in one piece by stamping or milling. The maintenance cost is extremely low, and there are no vulnerable parts that need to be replaced regularly.

[0027] VII. The stable design of the rotating shaft mechanism and the rotary thrust mechanism enhances the overall structural load-bearing strength and transmission efficiency. The rotating shaft mechanism ensures the positional accuracy of the rotation fulcrum, preventing the formation of clearances over long-term use; the rotary thrust mechanism eliminates radial off-center loads during lever arm switching, extends the service life of hydraulic seals, reduces the risk of hydraulic oil leakage, and, with no redundant transmission components, significantly increases transmission efficiency. The force amplification effect of the large lever ratio can be fully transmitted to the piston, resulting in a substantial improvement in braking efficiency. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the present invention in the initial stage of braking.

[0029] Figure 2 This is a schematic diagram of the structure of the present invention at the critical point between the front and rear stages of braking.

[0030] Figure 3 This is a schematic diagram of the structure of the present invention at the rear of the braking section.

[0031] Figure 4 This is an exploded view of the structure of the present invention.

[0032] Figure 5 This is a structural schematic diagram of the lever arm switching component.

[0033] Figure 6 This is a cross-sectional view and a partial enlarged view of the present invention at the initial braking stage.

[0034] Figure 7 This is a cross-sectional view and a partially enlarged view of the present invention at the critical point between the front and rear braking stages.

[0035] Figure 8 This is a cross-sectional view and a partial enlarged view of the present invention at the rear of the brake section.

[0036] Figure 9 This is a cross-sectional view of the present invention from another angle.

[0037] Explanation of reference numerals in the attached drawings: 1. Brake housing; 1a. Piston chamber; 101. Front opening; 102. Rear opening; 103. Second fixing hole; 104. First groove; 105. Guide rib; 2. Piston assembly; 21. Piston body; 22. Piston spring; 3. Push rod assembly; 4. Brake handle; 41. First rotating hole; 42. Grip section; 43. Bearing hole; 5. Lever switching component; 51. First rotation fulcrum; 511. First fixing hole; 52. Second rotation fulcrum; 521. Second rotating hole; 53. Front section; 54. Rear section; 55. Second groove; 56. 6. Receiving cavity; 7. First rotating shaft mechanism; 8. First rotating section; 9. First fixed section; 10. Second rotating shaft mechanism; 11. Second rotating section; 12. Second fixed section; 13. Driving component; 14. Guiding component; 15. Reset assembly; 16. First spring; 17. Ball bearing; 18. Rotary push mechanism; 19. Drive shaft; 10. Third fixed hole; 11. Drive hole; 12. Third rotating section; 13. Rotary push bearing; 14. Rotary push connector; 15. Third fixed section; L1. Initial arc path; L2. Rear arc path. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Reference Figures 1 to 9 This invention provides a variable lever arm brake, which is primarily adapted to bicycle hydraulic braking systems and is also compatible with various hydraulic braking scenarios such as electric vehicles and motorcycles. Its specific structure includes the following: The brake housing 1, serving as the load-bearing base of the overall structure, has a piston chamber 1a (filled with brake fluid) machined inside. The piston chamber 1a has a front opening 101 and a rear opening 102. The front opening 101 is used to connect to the hydraulic oil pipe, and the rear opening 102 is used for the push rod assembly 3 to pass through. A piston assembly 2 is movably disposed inside the piston chamber 1a. The piston assembly 2 includes a piston body 21 and a piston spring 22. A hydraulic sealing ring is generally provided between the outer wall of the piston body 21 and the inner wall of the piston chamber 1a. The piston spring 22 abuts against the front inner wall of the piston chamber 1a and the front end of the piston body 21. The piston spring 22 acts on the piston body 21, causing it to always have a tendency to move backward (reset).

[0041] The push rod assembly 3 is located at the rear end of the piston assembly 2. The front end of the push rod assembly 3 abuts against the rear end of the piston body 21 to form a transmission engagement. The rear end of the push rod assembly 3 is connected to the brake handle 4 through the rotary push mechanism 12. The brake handle 4 drives the piston body 21 to move back and forth along the piston chamber 1a through the push rod assembly 3, thereby realizing the establishment and release of hydraulic pressure. The brake handle 4 has a grip section 42 for user operation. The shape of the grip section 42 is ergonomic, and the surface is provided with anti-slip texture to improve grip comfort and operational stability.

[0042] Reference Figure 1 , Figure 4 and Figure 5 As the core innovative structure of this embodiment, the brake also includes a lever arm switching component 5, a drive component 8, a guide component 9, a first guide mechanism, and a second guide mechanism. The lever arm switching component 5 is an independent, standardized component that can be replaced according to different vehicle models and braking force requirements without modifying core components such as the brake housing 1 and brake handle 4, thus reducing adaptation and maintenance costs. The lever arm switching component 5 is provided with a first rotation fulcrum 51, a second rotation fulcrum 52, a front section 53, and a rear section 54. Both the first rotation fulcrum 51 and the second rotation fulcrum 52 are located between the front section 53 and the rear section 54, with the first rotation fulcrum 51 located above the second rotation fulcrum 52.

[0043] The first rotation fulcrum 51 is connected to the upper part of the brake handle 4 through the first rotating shaft mechanism 6, so that the brake handle 4 and the lever arm switching component 5 form a stable rotational fit; the second rotation fulcrum 52 is connected to the upper part of the brake housing 1 through the second rotating shaft mechanism 7, so that the lever arm switching component 5 and the brake housing 1 form a stable rotational fit. Specifically, the first rotating shaft mechanism 6 is a stepped pin, including a first rotating section 61 and a first fixed section 62 arranged coaxially, the diameter of the first rotating section 61 being smaller than the diameter of the first fixed section 62. The upper part of the brake handle 4 has a first rotating hole 41, the first rotating section 61 is inserted into the first rotating hole 41, forming a clearance fit with the brake handle 4 to achieve smooth rotation; the first rotating fulcrum 51 has a first fixed hole 511, the first fixed section 62 is press-fitted into the first fixed hole 511, forming a fixed fit with the lever arm switching component 5 to ensure the positional accuracy of the first rotating fulcrum.

[0044] The second rotating shaft mechanism 7 is also a stepped pin shaft, including a second rotating section 71 and a second fixed section 72 arranged coaxially. The diameter of the second rotating section 71 is smaller than the diameter of the second fixed section 72. A second rotating hole 521 is provided at the second rotating fulcrum 52. The second rotating section 71 is inserted into the second rotating hole 521, forming a clearance fit with the lever arm switching component 5 to achieve smooth rotation. A second fixed hole 103 is provided at a corresponding position on the upper part of the brake housing 1. The second fixed section 72 is press-fitted into the second fixed hole 103 to form a fixed fit with the brake housing 1, ensuring the load-bearing strength of the second rotating fulcrum and meeting the force requirements of the large torque of the braking section.

[0045] Reference Figure 1 , Figure 6 As shown, in the initial braking phase, the drive component 8 and guide component 9 do not contact the lever arm switching component 5 and therefore do not function, thus ensuring that the brake handle 4 rotates about the first rotation fulcrum 51. Simultaneously, since the brake handle 4 and the lever arm switching component 5 do not transmit force, no additional locking mechanism is needed to achieve relative stillness between the lever arm switching component 5 and the brake housing 1, completely avoiding the fulcrum movement problem in the initial stroke of the prior art.

[0046] Reference Figure 3 , Figure 8 As shown, in the braking stage, the drive component 8 and the guide component 9 act on the front and rear ends of the lever arm switching component 5, respectively, providing dual-section (both sides of the rotation center) limiting and force transmission functions during the rotation of the lever arm switching component 5. Specifically, a pair of balanced transmission couples are formed on both sides of the rotation center, synchronously driving the lever arm switching component 5 to rotate around the second rotation fulcrum 52. The dual-side synchronous force structure completely offsets the radial off-center load generated by single-side drive, avoiding warping of the lever arm switching component 5 and unilateral wear of the shaft. The transmission link is shock-free and jam-free, achieving a linear and smooth transition of lever arm switching.

[0047] Reference Figure 1 , Figure 5 and Figure 6 The first guiding mechanism includes a first groove 104 formed on the brake housing 1 and a second groove 55 formed on the lever arm switching member 5. Both the first groove 104 and the second groove 55 are arc-shaped, and the initial arc path L1 of both is centered on the center of the first rotation fulcrum 51. The arc length is exactly equal to the idle stroke length of the initial braking phase. The first groove 104 and the second groove 55 are arranged facing each other. The driving member 8 is a cylindrical rib integrally formed on the brake handle 4. Its diameter is adapted to the width of the first groove 104 and the second groove 55 to ensure that the driving member 8 moves smoothly in the groove without radial clearance.

[0048] Specifically, the first groove 14 and the second groove 55 are both concentrically arranged with the center of the first rotation fulcrum 51 as the center and radius R1 as the radius; the movement trajectory of the guide component 9 is also concentrically arranged with the center of the first rotation fulcrum 51 as the center and radius R2 as the radius. When the brake handle 4 is rotated, the drive component 8 can move along the concentric arc trajectory within the first groove 14 and the second groove 55 to achieve precise guidance and self-locking.

[0049] Reference Figures 6 to 7 In the initial braking phase, the drive component 8 is located in and constrained by the first groove 14, allowing it to move along the same initial arc path L1, with the first rotation fulcrum 51 as its center. Self-locking function analysis: The force exerted by the drive component 8 on the sidewall of the first groove 14 is F. Since the first groove 14 is arc-shaped and its center is the first rotation fulcrum 51, the direction of the force F always points towards the first rotation fulcrum 51 along the radial direction. The torque generated by this force F on the second rotation fulcrum 52 is: M = F × d, where d is the perpendicular distance from the second rotation fulcrum 52 to the line of action of the force F. Since the line of action of the force F passes through the first rotation fulcrum 51, and the first rotation fulcrum 51 is the rotational connection point between the multi-point linkage component 5 and the brake handle 4, for the multi-point linkage component 5, the force F is an internal force, and its torque on the second rotation fulcrum 52 is d = 0, i.e., M = 0. In summary, no matter how much squeezing force the user applies during the initial braking phase, the torque generated by the drive component 8 around the second rotation fulcrum 52 by the multi-point linkage component 5 is always zero, and the multi-point linkage component 5 will not rotate around the second rotation fulcrum 52, thus achieving absolute self-locking of the second rotation fulcrum 52.

[0050] On the other hand, the second guiding mechanism includes a guide rib 105 integrally formed on the brake housing 1. The guide rib 105 extends from the end of the first groove 104 toward the side where the grip section 42 is located. The upper surface of the guide rib 105 is an arc-shaped guide surface. The arc path L2 of the rear section of the arc-shaped guide surface is centered on the center of the second rotation fulcrum 52, and the arc length is exactly equal to the braking stroke length of the rear section of the brake. After the drive component 8 disengages from the first groove 104, its outer cylindrical surface forms a sliding fit with the arc-shaped guide surface and moves along the rear arc path L2.

[0051] Reference Figures 7 to 8 In the later stage of braking, the drive component 8 disengages from the first groove 14 and releases the constraint of the first groove 14, allowing the drive component 8 to disengage from the initial arc path L1 and move along the later arc path L2 with the assistance of the guide rib 105. The motion principle after unlocking is as follows: After the drive component 8 disengages from the first groove 14, the brake handle 4 continues to rotate, and the drive component 8 contacts the front point 53 of the multi-pivot linkage component 5 and applies a transmission force. At this time, the direction of the force F no longer points to the first rotation fulcrum 51, but generates a rotational torque M=F×d (d>0) around the second rotation fulcrum 52, driving the multi-pivot linkage component 5 to rotate around the second rotation fulcrum 52 on a fixed axis, entering the braking force amplification stage with a large lever ratio.

[0052] Preferably, the length of the initial arc path L1 is exactly equal to the length of the initial travel of the brake.

[0053] Reference Figure 5 and Figure 6 A receiving cavity 56 is provided on the rear section 54 of the lever arm switching component 5. A reset assembly 10 is disposed in the receiving cavity 56, which includes a first spring 1011 and a ball bearing 1012. The receiving cavity 56 has an opening facing the guide component 9. The first spring 1011 is a compression spring, disposed between the ball bearing 1012 and the inner wall of the receiving cavity 56. The first spring 1011 applies an outward force to the ball bearing 1012, ensuring that the ball bearing 1012 remains in contact with the surface of the guide component 9. The guide component 9 is an arc-shaped rib integrally formed on the brake handle 4, and its arc-shaped surface forms a rolling fit with the ball bearing 1012, reducing frictional resistance.

[0054] Reference Figure 4 As shown, to adapt to the change in the rotation trajectory of the brake handle 4 during the lever arm switching process, the lower part of the brake handle 4 forms a transmission connection with the push rod assembly 3 through the rotary push mechanism 12. (Refer to...) Figure 4 and Figure 9The rotary actuator 12 includes a drive shaft 121, a rotary bearing 122, and a rotary connector 123. A bearing hole 43 is provided at the lower part of the brake handle 4, and the rotary bearing 122 is press-fitted into the bearing hole 43. The rotary connector 123 includes a third fixed section 1231, and a third rotating section 1213 is provided on the drive shaft 121. The third rotating section 1213 is inserted into the inner hole of the rotary bearing 122, forming an interference fit. A third fixed hole 1211 is provided at the end of the drive shaft 121, and the third fixed section 1231 is press-fitted into the third fixed hole 1211, forming a fixed fit with the drive shaft 121. A drive hole 1212 is provided in the middle of the drive shaft 121, and the rear end of the push rod assembly 3 is press-fitted into the drive hole 1212, forming a fixed fit with the drive shaft 121, thereby achieving stable transmission between the brake handle 4 and the push rod assembly 3. The omnidirectional rotational fit of the thrust bearing 122 can perfectly adapt to the rotational trajectory changes of two different rotational fulcrums, eliminate the radial off-center load of the push rod assembly 3 during the lever arm switching process, and avoid uneven wear between the piston body 21 and the piston chamber 1a.

[0055] Reference Figures 1 to 9 The working principle of this embodiment is as follows: Initial state (brake lever 4 not squeezed): Refer to Figure 1 , Figure 6 As shown, the piston spring 22 pushes the piston body 21 to move backward, which in turn drives the brake handle 4 to return to its initial position via the push rod assembly 3 and the rotary push mechanism 12. At this time, the drive component 8 is simultaneously located at the starting end of the first groove 104 and the second groove 55, forming a first stroke space between itself and the front section 53 of the lever arm switching component 5; a second stroke space is formed between the guide component 9 and the rear section 54 of the lever arm switching component 5; the ball bearing 1012 in the reset assembly 10 is always in contact with the surface of the guide component 9 under the action of the first spring 1011, and the lever arm switching component 5 remains stationary relative to the brake housing 1. At this time, a first input lever arm is formed between the first rotation fulcrum 51 and the gripping section 42, and a second input lever arm is formed between the second rotation fulcrum 52 and the gripping section 42. The length of the first input lever arm is less than the length of the second input lever arm, and an output lever arm is formed between the rotary push mechanism 12 and the piston assembly 2.

[0056] The ratio of the output lever arm to the input lever arm (either the first or second input lever arm) is the brake lever ratio. The size of the brake lever ratio directly determines the braking force amplification factor, brake travel, feel linearity, and handling safety. Specific lever ratio values ​​can be customized according to requirements and are not specifically limited here.

[0057] Initial braking phase (first lever arm state): Refer to Figure 1 , Figure 2 , Figure 6 , Figure 7As shown, when the user squeezes the grip section 42 of the brake handle 4, the brake handle 4 rotates forward relative to the lever arm switching component 5 and the brake housing 1 with the center of the first rotation fulcrum 51 as the center. During this process, the drive component 8 is simultaneously constrained by the first groove 104 and the second groove 55, and moves along the initial arc path L1, gradually approaching the front section 53 of the lever arm switching component 5; the guide component 9 moves along a concentric arc trajectory with the first rotation fulcrum 51 as the center, gradually approaching the rear section 54 of the lever arm switching component 5; the ball bearing 1012 rolls on the surface of the guide component 9, and the first spring 1011 is slightly compressed, providing uniform damping force.

[0058] Since the force exerted by the driving component 8 on the sidewall of the groove (first groove 104 or / and second groove 55) always points towards the first rotation fulcrum 51, and the force exerted by the guiding component 9 on the multi-fulcrum linkage component 5 also points towards the first rotation fulcrum 51, and neither has a tangential component, no torque is generated that would cause the multi-fulcrum linkage component 5 to rotate around the second rotation fulcrum 52, thus achieving pure geometric self-locking. No matter how much pinching force the user applies, the lever arm switching component 5 will not rotate around the second rotation fulcrum 52 and will always remain relatively stationary with respect to the brake housing 1.

[0059] The brake handle 4 drives the push rod assembly 3 forward via the rotary mechanism 12, pushing the piston body 21 to compress the piston spring 22 and quickly eliminate the idle stroke of the hydraulic system. During this stage, the brake handle 4 rotates around the first rotation fulcrum 51, with a short input lever arm, small leverage ratio, and requires less effort to squeeze, resulting in a light operating feel.

[0060] The critical point between the initial and final braking stages: Refer to Figure 2 , Figure 7 As shown, when the user continues to squeeze the brake lever 4 to the end of the idle stroke, the drive component 8 just moves to the end of the first groove 104 and the second groove 55, and is about to break free from the constraint of the groove. At this time, the drive component 8 just contacts the front section 53 of the lever arm switching component 5, and at the same time, the outer cylindrical surface of the drive component 8 begins to contact the arc-shaped guide surface of the guide rib 105, and is about to enter the rear arc path L2.

[0061] At this instant, the constraints of the first guide mechanism are about to be released, the constraints of the second guide mechanism are about to take effect, and the lever arm switching component 5 is about to switch from a stationary state to a rotating state. The entire transition process is smooth and without impact.

[0062] Rear braking phase (second lever arm state): Refer to Figure 2 , Figure 3 , Figure 7 , Figure 8As shown, when the user continues to squeeze the brake handle 4, the drive component 8 completely disengages from the constraints of the first groove 104 and the second groove 55, releasing the self-locking function of the second rotation fulcrum 52. At this time, the drive component 8 contacts the front section 53 of the lever arm switching component 5 and forms a transmission engagement. Simultaneously, the outer cylindrical surface of the drive component 8 is in close contact with the arc-shaped guide surface of the guide rib 105, and is constrained by the second guide mechanism, moving along the rear arc path L2.

[0063] The drive component 8 applies a forward transmission force to the front section 53 of the lever arm switching component 5. This transmission force generates a rotational torque about the center of the second rotation fulcrum 52, causing the lever arm switching component 5 to rotate about the second rotation fulcrum 52. The guide component 9 moves forward synchronously, and the ball bearing 1012 continues to roll on the surface of the guide component 9. The first spring 1011 is further compressed, providing a continuous damping force to ensure smooth transmission.

[0064] During this stage, the brake handle 4 rotates around the second pivot point 52, significantly increasing the input lever arm and lever ratio, resulting in a significant force amplification effect. This allows the push rod assembly 3 to drive the piston body 21 to establish high-pressure hydraulic pressure, achieving a large braking force output and drastically shortening the braking distance. The arc-shaped guide surface of the second guide mechanism precisely constrains the motion trajectory of the drive component 8, ensuring that the lever arm switching component 5 always rotates on a fixed axis without any offset or jamming, ensuring a stable and smooth transmission link.

[0065] Release and reset: Refer to Figures 3 to 1 , Figures 8 to 6 As shown, when the user releases the brake handle 4, the piston spring 22 pushes the piston body 21 to return to its original position, which in turn drives the brake handle 4 to rotate in the opposite direction via the push rod assembly 3. At the same time, the first spring 1011 releases its elastic force, which applies a reverse thrust to the guide component 9 through the ball bearing 1012, assisting the brake handle 4 and the lever arm switching component 5 to return to their original positions synchronously.

[0066] In the initial reset phase, the guide component 9 on the brake handle 4 contacts and transmits force to the lever arm switching component 5 through the reset assembly 10 (ball bearing 1012 and first spring 1011), causing the lever arm switching component 5 to rotate in the opposite direction (with the second rotation fulcrum 52 as the center of rotation) to reset. The drive component 8 moves in the opposite direction along the rear arc path L2 and re-enters the first groove 104. In the later reset phase, the pure geometric self-locking structure of the first guide mechanism takes effect again, and the lever arm switching component 5 stops rotating. The guide component 9 moves in the opposite direction along the concentric arc trajectory, gradually moving away from the rear section 54 of the lever arm switching component 5. When the drive component 8 returns to the starting end of the first groove 104, the reset process ends, and the brake handle 4 returns to its initial position, ready for the next braking.

[0067] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the invention shall still fall within the protection scope of the present invention.

Claims

1. A brake with a variable lever arm, the brake housing having a piston chamber having a front opening and a rear opening; A piston assembly, which is movably disposed in the piston chamber; The push rod assembly is positioned at the rear end of the piston assembly, and the push rod assembly and the piston assembly form a transmission engagement. A brake handle is used to drive the push rod assembly, and the brake handle drives the piston assembly to move through the push rod assembly; A lever arm switching component has at least a first rotation fulcrum and a second rotation fulcrum; the first rotation fulcrum is connected to the brake handle through a first rotating shaft mechanism so that the brake handle and the lever arm switching component form a rotational engagement; the second rotation fulcrum is connected to the brake housing through a second rotating shaft mechanism so that the lever arm switching component and the brake housing form a rotational engagement. Its characteristic is that it further includes: A drive component is disposed on the brake handle, and the drive component moves together with the brake handle; In the initial stage of braking, there is a first stroke space between the drive component and the lever arm switching component. The drive component moves along the first stroke space and gradually approaches the lever arm switching component. During this process, the brake handle rotates around the first rotation fulcrum, and the lever arm switching component remains stationary relative to the brake housing. In the later stage of braking, the drive component contacts the lever arm switching component and forms a transmission engagement; during this process, the brake handle drives the lever arm switching component to rotate together around the second rotation fulcrum through the drive component. The brake handle has a gripping section, a first input force arm is formed between the first rotation fulcrum and the gripping section, and a second input force arm is formed between the second rotation fulcrum and the gripping section. The length of the first input force arm is less than the length of the second input force arm.

2. The brake with variable lever arm according to claim 1, characterized in that: It also includes a first guide mechanism, which includes a first groove formed on the brake housing and a second groove formed on the lever arm switching member. Both the first groove and the second groove have groove openings for the drive component to enter and exit, and the first groove and the second groove are arranged facing each other, forming an arc path L1 between the first groove and the second groove. In the initial braking phase, the drive component is located in the first groove and constrained by the first groove, so that the drive component moves along the initial arc path L1, and the initial arc path L1 is centered on the first rotation fulcrum; in the later braking phase, the drive component disengages from the first groove and is released from the constraint of the first groove, so that the drive component moves away from the initial arc path L1.

3. The brake with variable lever arm according to claim 2, characterized in that: It also includes a second guiding mechanism, which includes a guide rib disposed on the brake housing. The guide rib extends from the first groove toward the side where the grip section is located. The guide rib has an arc-shaped guide surface to form a rear arc path L2. In the later stage of braking, the drive component contacts the force arc guide surface, so that the drive component moves along the arc path L2, and the arc path L2 is centered on the second rotation fulcrum; during this process, the brake handle drives the power arm switching component to rotate together with the drive component around the second rotation fulcrum.

4. The brake with variable lever arm according to claim 1, characterized in that: It also includes a guide component disposed on the brake handle, the guide component moves together with the brake handle, and there is a second stroke space between the guide component and the lever arm switching component; The lever arm switching component has a front section and a rear section. The driving component is in contact with the front section, and the guiding component is in contact with the rear section through a reset assembly. The first and second rotation fulcrums are both located between the front and rear sections. During the squeezing of the brake handle, the guide component moves along the second stroke space and causes the reset component to gradually approach the lever arm switching component.

5. The brake with variable lever arm according to claim 4, characterized in that: The driving component is a cylindrical rib disposed on the brake handle, and the guiding component is an arc-shaped rib disposed on the brake handle.

6. The brake with variable lever arm according to claim 4, characterized in that: The lever arm switching component is also provided with a receiving cavity, and the reset component includes a first spring and a ball ball disposed in the receiving cavity; The receiving cavity has a cavity opening facing the guide component, and the first spring is disposed between the ball and the inner wall of the receiving cavity, and the first spring applies an outward force to the ball so that the ball is always in contact with the guide component.

7. The brake with variable lever arm according to claim 1, characterized in that: The first rotating shaft mechanism includes a first rotating section and a first fixed section; The brake handle has a first rotating hole, and the first rotating section is connected to the first rotating hole and forms a rotating engagement with the brake handle; The first rotation fulcrum has a first fixing hole, and the first fixing section is connected to the first fixing hole and forms a fixed fit with the lever arm switching component.

8. The brake with variable lever arm according to claim 1, characterized in that: The second rotating shaft mechanism includes a second rotating section and a second fixed section; A second rotating hole is provided at the second rotating fulcrum, and the second rotating section is connected to the second rotating hole and forms a rotating engagement with the lever arm switching component; The brake housing has a second fixing hole, and the second fixing section is connected to the second fixing hole and forms a fixed fit with the brake housing.

9. The brake with variable lever arm according to claim 1, characterized in that: The brake handle is connected to the push rod assembly via a rotary mechanism; The aforementioned rotary mechanism includes a drive shaft, a rotary bearing, and a rotary connector; The brake handle has a bearing hole, and the thrust bearing is installed in the bearing hole; The rotary connector includes a third fixed section, and the drive shaft has a third rotating section; the third rotating section is connected to the bearing inner hole of the rotary bearing and forms a rotational fit with the rotary bearing; the drive shaft has a third fixed hole, and the third fixed section is connected to the third fixed hole and forms a fixed fit with the drive shaft. The drive shaft has a drive hole, and the push rod assembly is connected to the drive hole and forms a fixed fit with the drive shaft, so that the brake handle forms a transmission fit with the push rod assembly through the rotary mechanism.

10. The brake with a variable lever arm according to claim 1, characterized in that: The piston assembly includes at least a piston body and a piston spring. The rear end of the piston body contacts the thrust assembly and forms a transmission engagement. The piston spring abuts against the inner wall of the piston chamber and the front end of the piston body. The piston spring acts on the piston body so that the piston body always has a tendency to move backward.

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