Brake pedal structure with variable lever ratio and vehicle

Abstract

The invention discloses a brake pedal structure with a variable lever ratio and a vehicle. The brake pedal structure comprises a main pedal arm, a pedal base support, a pedal rocker arm and a two-force rod. The main pedal arm is hinged to the pedal base support through a pedal main pin. One end of the pedal rocker arm is hinged with the main pedal arm through a pin shaft, and the other end is hinged with the two-force rod; the two-force rod is rotationally installed on the pedal base support through a base support pin shaft. When the main pedal arm moves under treading force, the pedal rocker arm and the two-force rod rotate in a linkage mode, the distance between a master pump pin hole in the two-force rod and a pedal master pin is dynamically changed, and therefore the lever ratio is increased firstly and then decreased along with the opening degree of the pedal. On the basis of a traditional brake pedal with a fixed lever ratio, a mechanical structure of the rocker arm and the two-force rod is additionally arranged between the pedal arm and the base support, the lever ratio of the brake pedal can be adjusted within a certain range, the increasingly stringent pedal feeling requirement is met, the cost of a brake system is not increased, and the brake pedal is very suitable for a current traditional automobile.

Description

Technical Field

[0001] This invention relates to the field of vehicle braking system technology, specifically to a variable lever ratio brake pedal structure and vehicle. Background Technology

[0002] Existing technologies primarily employ a fixed lever ratio brake pedal structure, coupled with a vacuum booster and ESC (Electronic Stability Control) system, to meet the cost control requirements of traditional automobiles. However, with the automotive industry's increasing demands for braking performance, especially the stricter limitations on caliper drag and the increased fluid requirements of the brake caliper cylinders, fixed lever ratio pedals have revealed the following serious drawbacks:

[0003] Fixed lever ratios (such as the common 3.3) cannot adapt to dynamic braking demands. During the initial braking phase, a fixed lever ratio results in excessive free travel and noticeable pedal play, affecting driver comfort and responsiveness. During the later braking phase, an unchanged lever ratio can cause a sudden increase in braking force, leading to excessive pressure, braking jerking, and reduced driving smoothness. This is because fixed lever ratio structures lack flexibility and cannot adjust the force transmission ratio according to pedal opening. In low-cost solutions using vacuum boosters and ESC, the increased fluid requirement exacerbates pedal feel imbalance and complicates matching. When the brake assist system fails (e.g., vacuum pump malfunction), the driver must rely on purely mechanical braking. With a fixed lever ratio, the braking force generated by the same pedal force is limited, extending the braking distance and threatening driving safety. Data shows that in scenarios of brake assist failure, the braking efficiency of a fixed lever ratio pedal decreases by approximately 20-30%, failing to meet emergency braking requirements. Existing variable lever ratio pedals achieve this by adjusting the length of the main pedal arm, resulting in a complex structure, low reliability, and high precision requirements, increasing manufacturing costs and failure rates. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a variable leverage ratio brake pedal structure and vehicle. Based on the traditional fixed leverage ratio brake pedal, a mechanical structure consisting of a rocker arm and a two-force bar is added between the pedal arm and the base bracket. This allows the leverage ratio of the brake pedal to be adjusted within a certain range, satisfying increasingly stringent pedal feel requirements without increasing the cost of the braking system, making it very suitable for current traditional automobiles.

[0005] The technical solution of the present invention is as follows: In a first aspect of the invention, a brake pedal structure with a variable leverage ratio is provided, comprising a main pedal arm, a pedal base bracket, a pedal rocker arm, and a two-force bar; the main pedal arm is hinged to the pedal base bracket via a pedal kingpin; one end of the pedal rocker arm is hinged to the main pedal arm via a pin, and the other end is hinged to the two-force bar; the two-force bar is rotatably mounted on the pedal base bracket via a pin on the base bracket. When the main pedal arm moves under the force of being stepped on, the pedal rocker arm and the two-force bar rotate in conjunction, causing the distance between the master pump pin hole on the two-force bar and the pedal kingpin to change dynamically, thereby realizing that the lever ratio first increases and then decreases with the pedal opening.

[0006] In some embodiments of the present invention, the pedal rocker arm is a rod, and the top end of the pedal rocker arm is rotatably mounted on the side of the main pedal arm, and the mounting position is close to the top of the main pedal arm.

[0007] In some embodiments of the present invention, the two-force bar is L-shaped, one end of the two-force bar is provided with a first hinge seat, the bottom end of the pedal rocker arm is installed in the first hinge seat by a pin, and the other end of the two-force bar is provided with a hinge hole.

[0008] In some embodiments of the present invention, a second hinge seat is provided on the pedal base bracket. The second hinge seat is horizontally arranged, and the end of the two force rod with the hinge hole is installed in the second hinge seat through the base bracket pin.

[0009] In some embodiments of the present invention, the master cylinder pin hole on the two-force bar is located at the torsion angle of the L-shaped two-force bar, and the master cylinder pin hole is connected to the brake master cylinder.

[0010] In some embodiments of the present invention, the lever ratio i is calculated as i=a / b, where a is the fixed distance from the tread point of the main pedal arm to the pedal kingpin, and b is the real-time distance between the master cylinder pin hole and the kingpin.

[0011] In some embodiments of the present invention, the lever ratio variation curve is customized by adjusting the length of the two-force bar or the length of the pedal rocker arm.

[0012] In some embodiments of the present invention, the top of the main pedal arm is hinged to the pedal base bracket via a pedal kingpin, and the pedal is fixedly mounted on the bottom of the main pedal arm.

[0013] In a second aspect of the invention, a vehicle is provided, including a brake pedal structure with a variable lever ratio.

[0014] In some embodiments of the present invention, the variable lever ratio brake pedal structure is applied to the front of the vehicle body and connected to the master cylinder.

[0015] One or more technical solutions of the present invention have the following beneficial effects: (1) The present invention adds a rocker arm and a two-force bar mechanical structure between the pedal arm and the base bracket, which can adjust the leverage ratio of the brake pedal within a certain range. When the brake assist fails, the driver can press the pedal harder to bring a greater leverage ratio to improve driving safety. In addition, by changing the length of the rocker arm or the two-force bar, the leverage ratio can be adjusted within a certain range. A smaller leverage ratio at the front can solve the problem of a large pedal travel at the front, while a larger leverage ratio at the rear can solve the problem of excessive pressure at the rear. When the brake assist fails, the driver can press the pedal harder to bring a greater leverage ratio to improve driving safety.

[0016] (2) This invention improves the brake pedal feel through an innovative mechanical linkage structure. Its core principle lies in utilizing the linkage mechanism of the pedal rocker arm and the two-force bar to dynamically change the distance b between the master cylinder pin hole and the pedal kingpin with the pedal opening, thereby achieving intelligent adjustment of the lever ratio i (i=a / b). This smooth lever ratio transition allows the driver to obtain precise foot feedback, significantly improving braking control accuracy. Actual test data shows that this structure improves the pedal feel score by more than 30% and reduces free travel by 40%, making it particularly suitable for congested urban road conditions requiring frequent braking.

[0017] (3) The ingenious structural design of the present invention achieves a wide range of platform adaptability while controlling costs. The four-component linkage mechanism (main pedal arm, pedal base bracket, pedal rocker arm, and two-force bar) adopts a standardized manufacturing process, which reduces costs by about 30% compared with the electronically controlled variable lever ratio scheme. Moreover, it does not require modification of the existing vacuum booster + ESC system architecture. By adjusting the length of the two-force bar or the installation position of the pedal rocker arm, different lever ratio change curves can be customized to adapt to different vehicle models. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the variable lever ratio brake pedal structure of the present invention; Figure 2 This is a schematic diagram of the variable lever ratio brake pedal structure of the present invention. Figure 3 This is a graph showing the relationship between the brake pedal lever ratio and the pedal opening.

[0019] In the diagram: 1. Main pedal arm; 2. Pedal base bracket; 3. Pedal rocker arm; 4. Two-force bar; 5. Pedal kingpin; 6. Base bracket pin; 7. First hinge seat; 8. Second hinge seat; a. Pedal arm length; b. Straight-line distance between master cylinder pin hole and pedal kingpin; c. Distance between master cylinder pin hole and pedal kingpin during operation; d. Two-force bar length; d. Rocker arm length; α, β. Angles of pedal movement. Detailed Implementation

[0020] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] Example 1 The technical concept of this invention is as follows: Taking a commonly used fixed-lever-ratio brake pedal as an example, assuming the current fixed-lever-ratio pedal has a leverage ratio of 3.3, if a new type of brake pedal were available that could change the leverage ratio during pedal depressing, making the initial leverage ratio 2.8 and the subsequent leverage ratio 4.0, according to the lever principle, a smaller leverage ratio would inevitably lead to a reduction in travel, solving the problem of excessive pedal travel at the beginning. A larger leverage ratio at the end would result in a greater travel and a slower pressure build-up rate, solving the problem of excessive pressure at the end. From another perspective, suppose the power assist system of a car's brake system fails. When the driver depresses the pedal forcefully, under the same pedal force, a larger leverage ratio would inevitably result in greater braking pressure, thus effectively shortening the braking distance and ensuring the safety of the driver and property.

[0023] Therefore, this embodiment proposes to change the leverage ratio by altering the distance between the master cylinder pin hole and the pedal kingpin. The superior pedal feel of new energy vehicles is constantly challenging that of traditional gasoline-powered vehicles. Given the ever-shrinking cost targets and increasingly demanding performance goals, achieving a better pedal feel by changing the brake pedal leverage ratio is a sound approach, delivering a superior experience at a limited cost.

[0024] In a typical embodiment of the present invention, a brake pedal structure with a variable lever ratio is proposed, such as... Figure 1 As shown, it includes a main pedal arm 1, a pedal base bracket 2, a pedal rocker arm 3, and a two-force bar 4; the main pedal arm 1 is hinged to the pedal base bracket 2 via a pedal main pin 5; one end of the pedal rocker arm 3 is hinged to the main pedal arm 1 via a pin, and the other end is hinged to the two-force bar 2; the two-force bar 2 is rotatably mounted on the pedal base bracket 2 via a base bracket pin 6; When the main pedal arm moves under the force of being stepped on, the pedal rocker arm and the two-force bar rotate in conjunction, causing the distance between the master pump pin hole on the two-force bar and the pedal kingpin to change dynamically, thereby realizing that the lever ratio first increases and then decreases with the pedal opening.

[0025] In actual use, when the driver presses the brake pedal, the pedal arm 1 moves forward, pushing the rocker arm 3, which in turn pushes the two-force bar 4 forward. Since the other end of the two-force bar is fixed to the pedal base bracket via the base bracket pin 6, it continuously rotates around the base bracket pin 6 during its movement. As the pedal opening increases, the distance b between the master cylinder pin hole and the pedal master pin also continuously changes, initially decreasing and then increasing, corresponding to a leverage ratio that initially increases and then decreases.

[0026] Specifically, the leverage ratio i is calculated using the formula i = a / b, where a is the fixed distance from the pedal arm's tread point to the pedal kingpin, and b is the real-time distance between the master cylinder pin hole and the kingpin. The leverage ratio variation curve is customized by adjusting the length of the two-force bar or the pedal rocker arm. Figure 2 As shown, because the two-force bar connects to the brake master cylinder, the distance *b* between the master cylinder pin hole and the pedal kingpin is constantly changing. Since the distance *a* between the pedal arm's tread point and the main shaft is constant, the leverage ratio *i* = *a* / *b* will continuously change. Assuming the pedal is pressed forward by an angle *β*, the distance *c* between the master cylinder pin hole and the pedal kingpin is *b* / *cosβ*; the corresponding leverage ratio *i* = *(a*cosβ)* / *b*. As the pedal opening increases, the leverage ratio first increases and then decreases. This aligns with the earlier point that a smaller leverage ratio at the beginning solves the problem of excessive pedal travel at the beginning, while a larger leverage ratio at the end solves the problem of excessive pressure at the end. Figure 3 As shown, as the brake pedal arm rotates, the straight-line distance between the master cylinder pin hole and the pedal kingpin first decreases and then increases, corresponding to the pedal lever ratio first increasing and then decreasing.

[0027] Since the distance b between the master cylinder pin hole and the pedal kingpin is affected by the length of the lever and rocker arm, the lever ratio can be adjusted within a certain range by adjusting the length of the lever and rocker arm, so as to achieve a customized lever ratio change curve according to different application needs.

[0028] In this embodiment, the pedal rocker arm is a rod with pin holes at both ends. The top end of the pedal rocker arm is rotatably mounted on the side of the main pedal arm, and the mounting position is close to the top of the main pedal arm.

[0029] In this embodiment, the two-force bar is L-shaped. One end of the two-force bar 4 is provided with a first hinge seat 7. The bottom end of the pedal rocker arm is installed in the first hinge seat through a pin. The other end of the two-force bar 4 is provided with a hinge hole. Further, a second hinge seat 8 is provided on the pedal base bracket 2. The second hinge seat 8 is horizontally arranged. The end of the two-force bar 4 with the hinge hole is installed in the second hinge seat through a base bracket pin 6.

[0030] In this embodiment, the master cylinder pin hole on the two-force bar is located at the torsion angle of the L-shaped two-force bar, and the master cylinder pin hole is connected to the brake master cylinder.

[0031] In this embodiment, the top of the main pedal arm is hinged to the pedal base bracket via a pedal master pin, and the pedal is fixedly installed at the bottom of the main pedal arm.

[0032] This invention adds a rocker arm and a two-force bar between the pedal arm and the base bracket, which allows for adjustment of the brake pedal's leverage ratio within a certain range. When brake assist fails, the driver can apply more pressure to the pedal, resulting in a higher leverage ratio and improved driving safety. Furthermore, by changing the length of the rocker arm or two-force bar, the leverage ratio can be adjusted within a certain range; a lower leverage ratio at the beginning solves the problem of excessive pedal travel at the beginning, while a higher leverage ratio at the end solves the problem of excessive pressure at the end. When brake assist fails, the driver can apply more pressure to the pedal, resulting in a higher leverage ratio and improved driving safety.

[0033] Example 2 In one typical embodiment of the present invention, a vehicle is provided, including the variable lever ratio brake pedal structure of Embodiment 1, wherein the variable lever ratio brake pedal structure is applied to the front of the vehicle body and connected to the master cylinder of the brake.

[0034] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A brake pedal structure with a variable lever ratio, characterized in that, It includes a main pedal arm, a pedal base bracket, a pedal rocker arm, and a two-force bar; the main pedal arm is hinged to the pedal base bracket via a pedal main pin; one end of the pedal rocker arm is hinged to the main pedal arm via a pin, and the other end is hinged to the two-force bar; the two-force bar is rotatably mounted on the pedal base bracket via a pin on the base bracket; When the main pedal arm moves under the force of being stepped on, the pedal rocker arm and the two-force bar rotate in conjunction, causing the distance between the master pump pin hole on the two-force bar and the pedal kingpin to change dynamically, thereby realizing that the lever ratio first increases and then decreases with the pedal opening.

2. The brake pedal structure with variable lever ratio as described in claim 1, characterized in that, The pedal rocker arm is a rod with pin holes at both ends. The top end of the pedal rocker arm is rotatably mounted on the side of the main pedal arm, and the mounting position is close to the top of the main pedal arm.

3. The brake pedal structure with variable lever ratio as described in claim 1, characterized in that, The two-force bar is L-shaped. One end of the two-force bar is provided with a first hinge seat. The bottom end of the pedal rocker arm is installed in the first hinge seat through a pin. The other end of the two-force bar is provided with a hinge hole.

4. The brake pedal structure with variable lever ratio as described in claim 3, characterized in that, The pedal base bracket is provided with a second hinge seat, which is horizontally positioned. The end of the two force rod with the hinge hole is installed in the second hinge seat through the base bracket pin.

5. The brake pedal structure with variable lever ratio as described in claim 3, characterized in that, The master cylinder pin hole on the two-force member is located at the torsion angle of the L-shaped two-force member, and the master cylinder pin hole is connected to the brake master cylinder.

6. The brake pedal structure with variable lever ratio as described in claim 1, characterized in that, The lever ratio i is calculated using the formula i=a / b, where a is the fixed distance from the pedal arm's tread point to the pedal kingpin, and b is the real-time distance between the master cylinder pin hole and the kingpin.

7. The brake pedal structure with variable lever ratio as described in claim 6, characterized in that, Customize the lever ratio variation curve by adjusting the length of the lever arm or the pedal rocker arm.

8. The brake pedal structure with variable lever ratio as described in claim 1, characterized in that, The top of the main pedal arm is hinged to the pedal base bracket via a pedal kingpin, and the pedal is fixedly installed at the bottom of the main pedal arm.

9. A vehicle, characterized in that, The brake pedal structure includes the variable lever ratio as described in any one of claims 1-8.

10. The vehicle as claimed in claim 9, characterized in that, The variable lever ratio brake pedal structure is applied to the front of the vehicle body and connected to the master cylinder.

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