Pedal mechanism providing variable lever ratio and brake-by-wire pedal

Abstract

The utility model provides a pedal mechanism providing a variable lever ratio and a brake-by-wire pedal, and belongs to the technical field of vehicle brake pedals, the pedal mechanism comprises a pedal arm, the two ends of the pedal arm are respectively provided with a treading part and a first rotating center; a second rotating center is arranged at one end of the swinging arm; one end of the connecting rod arm is hinged to the pedal arm, and the other end of the connecting rod arm is hinged to the other end of the swing arm; the pedal arm is in linkage connection with the swing arm through the connecting rod arm to form a four-connecting-rod structure, and when a treading part is subjected to treading force, the pedal arm rotates around a first rotating center, and then the connecting rod arm drives the swing arm to rotate around a second rotating center; the utility model has the beneficial effects that the pedal arm, the connecting rod arm and the swinging arm are designed into a four-connecting-rod structure, the treading stroke of the pedal arm determines the position of the connecting rod arm, the position of the connecting rod arm determines the lever ratio of the four-connecting-rod structure, and when the treading stroke of the pedal arm is increased, the lever ratio is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to vehicle brake pedal technical field relates to a kind of pedal mechanism and line control brake pedal providing variable lever ratio. BACKGROUND

[0002] Line control brake pedal (Brake-by-wire) is a kind of automobile brake components, and the brake (brake caliper) is worked by sending electronic signal to ECU. When traditional brake pedal is stepped on, mechanical link or hydraulic system can be fed back to pedal a pedal force (resistance).And line control brake pedal needs to be set pedal force simulator to simulate this pedal force due to the design of mechanical link or hydraulic system being cancelled.

[0003] If pedal force is simulated by spring, since the spring force is proportional to compression amount (also can be understood as pedal stroke), so the pedal force obtained is linear.And the pedal force required by line control brake pedal is nonlinear, which is embodied in actual use as follows: the greater the pedal stroke, the greater the pedal force, and the traditional spring structure cannot provide this nonlinear pedal force.

[0004] At present, there are some structures that can provide nonlinear or variable pedal force, for example, a utility model patent with application number CN201820860086.9, named pedal assembly and vehicle with same, the working principle of the pedal assembly is as follows: a crank slider mechanism is designed to provide lever ratio, the spring force is formed into pedal force feedback to pedal arm after passing through the crank slider mechanism, and the lever ratio of the crank slider mechanism changes with pedal stroke, so that nonlinear pedal force can be provided by changing the lever ratio. However, the above structure is relatively complex, and the change of lever ratio depends on the sliding of slider, and the slider is prone to jamming or wear, so there is room for improvement. UTILITY MODEL CONTENTS

[0005] The utility model aims at the above problems existing in prior art, and provides a pedal mechanism and line control brake pedal providing variable lever ratio.

[0006] The utility model can be realized by the following technical scheme: a pedal mechanism providing variable lever ratio, comprising:

[0007] Pedal arm, both ends of the pedal arm are provided with a stepping position and a first rotation center respectively;

[0008] Swing arm, one end of the swing arm is provided with a second rotation center;

[0009] Connecting rod arm, one end of the connecting rod arm is hinged with the pedal arm, and the other end of the connecting rod arm is hinged with the other end of the swing arm.

[0010] The pedal arm is linked with the swing arm through the connecting rod arm and forms a four-bar linkage structure, when the pedal position is stepped, the pedal arm rotates around the first rotation center, and then drives the swing arm to rotate around the second rotation center through the connecting rod arm.

[0011] The pedal stroke of the pedal arm determines the position of the connecting rod arm, and the position of the connecting rod arm determines the lever ratio of the four-bar linkage structure; when the pedal stroke of the pedal arm increases, the lever ratio decreases.

[0012] Preferably, the pedal position is provided as point A, the first rotation center is provided as point B, the hinge point of the pedal arm and the connecting rod arm is provided as point C, the hinge point of the swing arm and the connecting rod arm is provided as point D, and the second rotation center is provided as point E, and a straight line passing through points C and D is provided as straight line CD.

[0013] When the pedal stroke of the pedal arm increases, the perpendicular distance between point B and straight line CD increases, and the perpendicular distance between point E and straight line CD decreases, so that the lever ratio decreases.

[0014] Preferably, the swing arm is provided with a force receiving position for abutting with one end of the spring, and the force receiving position is provided as point H.

[0015] Preferably, when point A of the pedal arm is subjected to pressure, point A of the pedal arm rotates around point B together with point C, point D of the swing arm rotates around point E together with point H, and the rotating direction of the pedal arm is opposite to that of the swing arm.

[0016] Preferably, point B of the pedal arm and point E of the swing arm are located on opposite sides, respectively, point C of the pedal arm is close to the side where point E is located, and point D of the swing arm is close to the side where point B is located.

[0017] Preferably, point A, point B and point C of the pedal arm form a triangular structure, and point A, point B and point C are three vertices of the triangular structure, respectively, point D, point H and point E of the swing arm form another triangular structure, and point D, point H and point E are three vertices of the other triangular structure, respectively.

[0018] A linear control brake pedal comprises the pedal mechanism for providing variable lever ratio.

[0019] Compared with the prior art, the pedal mechanism has the following beneficial effects:

[0020] 1、The pedal arm, connecting rod arm and swing arm are designed as a four-bar linkage structure, the position of the connecting rod arm is determined by the pedal stroke of the pedal arm, the lever ratio of the four-bar linkage structure is determined by the position of the connecting rod arm, and the lever ratio decreases when the pedal stroke of the pedal arm increases.

[0021] 2、The pedal mechanism is designed as a four-bar linkage structure, so that the whole pedal mechanism is compact and efficient, unnecessary complexity is reduced, the parts are connected in a hinged manner, the smoothness and stability of movement are ensured, and the failure risk is reduced, and the design is not prone to jamming or wear, and has high reliability and durability.

[0022] 3、During the pedaling process, since the points B and E are both hinged points, the positions do not change during the whole pedaling process, and the position of the connecting rod arm changes, which causes the perpendicular distance between the point B and the straight line CD and the perpendicular distance between the point E and the straight line CD to change, and the definition formula of the lever ratio is ratio=L AB ×L E->CD / (L B->CD ×L E->FH ), from the formula, it can be seen that the lever ratio is determined by the length of the force arm between the pedal arm and the connecting rod arm and the length of the force arm between the swing arm and the connecting rod arm, that is, when the perpendicular distance between the point B and the straight line CD and the perpendicular distance between the point E and the straight line CD change, the lever ratio naturally changes. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a structure exploded view of the pedal mechanism of the utility model.

[0024] Figure 2 It is a structure schematic view of the pedal mechanism of the utility model.

[0025] Figure 3 It is a schematic view of the pedal mechanism of the utility model when the initial state of the linear control brake pedal.

[0026] Figure 4 It is a schematic view of the pedal mechanism of the utility model when the stroke limit of the linear control brake pedal.

[0027] Figure 5 It is a schematic view of the pedal mechanism of the utility model when the initial state of the linear control brake pedal.

[0028] Figure 6 It is a schematic view of the pedal mechanism of the utility model when the stroke limit of the linear control brake pedal.

[0029] Figure 7 It is a simulation simulation diagram of the pedal arm stroke and pedal force of the linear control brake pedal of the utility model.

[0030] Figure 8This is a simulation diagram of the pedal arm stroke and lever ratio of the wire-controlled brake pedal of the present invention.

[0031] In the figure, 100, pedal arm; 110, pedaling part; 120, first rotation center; 200, swing arm; 210, second rotation center; 300, connecting rod arm; 400, spring. DETAILED DESCRIPTION

[0032] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0033] like Figures 1 to 8 As shown, a pedal mechanism providing a variable leverage ratio includes: a pedal arm 100, wherein both ends of the pedal arm 100 are respectively provided with a pedaling part 110 and a first rotation center 120; a swing arm 200, wherein one end of the swing arm 200 is provided with a second rotation center 210; a connecting arm 300, wherein one end of the connecting arm 300 is hinged to the pedal arm 100, and the other end of the connecting arm 300 is hinged to the other end of the swing arm 200; the pedal arm 100 is linked to the swing arm 200 through the connecting arm 300 to form a four-bar structure, when the pedaling part 110 is subjected to a pedaling force, the pedal arm 100 rotates around the first rotation center 120, and then drives the swing arm 200 to rotate around the second rotation center 210 through the connecting arm 300; the pedaling stroke of the pedal arm 100 determines the position of the connecting arm 300, and the position of the connecting arm 300 determines the leverage ratio of the four-bar structure; when the pedaling stroke of the pedal arm 100 increases, the leverage ratio decreases.

[0034] In a traditional braking system, when the driver depresses the brake pedal, the pedal's movement is transmitted to the master cylinder, which converts this action into hydraulic pressure and transmits it to the brake calipers on each wheel through hydraulic lines. As the pedal travel increases, the hydraulic pressure increases nonlinearly. Therefore, the driver will feel that the pedal force feedback increases nonlinearly with the increase in pedal travel. For a wire-controlled brake pedal, it is necessary to simulate this nonlinear pedal force by designing a pedal force simulation structure. Currently, some wire-controlled brake pedals use a crank slider structure to provide a variable lever ratio, but the crank slider structure increases the complexity of the system and potential wear points.

[0035] The pedal mechanism used in brake-by-wire pedals has the greatest feature of providing a variable leverage ratio through a four-bar linkage. This variable leverage ratio, combined with a linear spring force, creates a nonlinear pedal force. Specifically, as pedal travel increases, the leverage ratio of the four-bar linkage gradually decreases. As a result, the originally linear spring force, through this gradually changing leverage ratio, can produce nonlinear pedal force feedback.

[0036] In this brake-by-wire pedal, the pedal mechanism consists of a pedal arm 100, a connecting arm 300, and a swing arm 200. The pedal arm 100 is hinged to the pedal base, with a first rotation center 120 serving as the hinge point or axis between the two. The pedal portion 110 of the pedal arm 100 is the area directly affected by the driver. The connecting arm 300 is hinged at both ends to the pedal arm 100 and the swing arm 200, respectively. The connecting arm 300 acts as a lever and transmits motion. The swing arm 200 is hinged to the pedal base, with a second rotation center 210 serving as the hinge point or axis between the two. In an actual brake pedal, the spring 400 inside the pedal is connected to the swing arm 200. When the swing arm 200 rotates, it can compress the spring 400. The elastic force generated when the spring 400 is compressed acts on the swing arm 200 and is amplified by the connecting arm 300 and transmitted to the pedal arm 100 to form a pedal force. The lever ratio is variable, which means that the pedal force changes nonlinearly.

[0037] The operating logic and principle of the pedal mechanism's lever ratio change are as follows: When the pedal arm 100's pedal portion 110 (point A) is stepped on, the pedal arm 100 rotates about the first rotation center 120 (point B), driving the hinged link arm 300 to move. Simultaneously, the pedal arm 100, via the link arm 300, drives the swing arm 200 to rotate about the second rotation center 210 (point E). During this process, the position of the link arm 300 changes, causing changes in the moment arms between the pedal arm 100 and the link arm 300, as well as between the swing arm 200 and the link arm 300, thereby altering the lever ratio of the entire system.

[0038] Furthermore, for a brake-by-wire pedal, the pedal force is determined by both the spring force of spring 400 and the lever ratio. While the spring force of spring 400 varies linearly with the travel of pedal arm 100, the lever ratio also varies with the travel of pedal arm 100. Therefore, the resulting pedal force varies non-linearly with the travel of pedal arm 100.

[0039] The pedal mechanism features a four-bar linkage, making it compact and efficient, while reducing unnecessary complexity. Articulated connections between components ensure smooth and stable movement, minimizing the risk of failure. This design is also less susceptible to jamming and wear, ensuring high reliability and durability.

[0040] like Figures 1 to 6As shown, on the basis of the above embodiment, the treading position 110 is set as point A, the first rotation center 120 is set as point B, the hinging point of the pedal arm 100 and the connecting rod arm 300 is set as point C, the hinging point of the swing arm 200 and the connecting rod arm 300 is set as point D, the second rotation center 210 is set as point E, and the straight line passing through points C and D is set as straight line CD; when the treading stroke of the pedal arm 100 increases, the perpendicular distance between point B and straight line CD increases, and the perpendicular distance between point E and straight line CD decreases, so that the lever ratio decreases.

[0041] The specific working logic of the pedal mechanism is as follows: during treading, since points B and E are both hinging points, their positions do not change during the entire treading process, while the position of the connecting rod arm 300 changes, which leads to changes in the perpendicular distances between point B and straight line CD and between point E and straight line CD, and the definition formula of the lever ratio is ratio=L AB ×L E->CD / (L B->CD ×L E->FH ). As can be seen from the formula, the lever ratio is determined by the force arm lengths between the pedal arm 100 and the connecting rod arm 300 and between the swing arm 200 and the connecting rod arm 300, that is, when the perpendicular distances between point B and straight line CD and between point E and straight line CD change, the lever ratio naturally changes. More specifically, when the perpendicular distance between point B and straight line CD increases and the perpendicular distance between point E and straight line CD decreases, the lever ratio decreases according to the formula of the lever ratio.

[0042] On the basis of the above embodiment, the swing arm 200 is provided with a force receiving position for abutting against one end of the spring 400, and the force receiving position is set as point H.

[0043] It should be further noted that the other end of the spring 400 is in abutting connection with the pedal seat, and the abutting points of the two are set as point F. When the spring 400 is compressed, the distance between point F and point H decreases.

[0044] In the non-treading state, the spring 400 is in a natural stretching state, and the distance between point F and point H is the maximum; when the driver applies force at point A, the pedal arm 100 rotates around point B, drives the connecting rod arm 300 to move, the connecting rod arm 300 pushes the swing arm 200 to rotate around point E, and forces the spring 400 to be gradually compressed. With the increase of the pedal stroke, the movement of the swing arm 200 causes point H to move closer to point F, that is, the distance between point F and point H gradually decreases, and the spring force provided by the spring 400 also increases accordingly with the increase of the compression degree.

[0045] Based on the above embodiment, when point A of the pedal arm 100 is subjected to pressure, point A and point C of the pedal arm 100 rotate around point B together, and point D and point H of the swing arm 200 rotate around point E together, and the rotation direction of the pedal arm 100 is opposite to the rotation direction of the swing arm 200.

[0046] When point A is subjected to pedaling force, the pedal arm 100 rotates clockwise or counterclockwise around point B, while the swing arm 200 rotates counterclockwise or clockwise around point E. That is, by cleverly arranging the positions of the hinge points, the rotation directions of the pedal arm 100 and the swing arm 200 are opposite. Through this motion logic, when the pedal arm 100 rotates around point B, the vertical distance between point B and straight line CD increases, and the vertical distance between point E and straight line CD decreases, thereby reducing the leverage ratio when the stroke of the pedal arm 100 increases.

[0047] like Figures 1 to 8 As shown, it should be noted that the leverage ratio is defined as: ratio = L AB ×L E->CD / (L B->CD ×L E->FH ), rat io is the leverage ratio, L AB is the distance between point A and point B, L E->CD is the vertical distance between point E and line CD, L B->CD is the vertical distance between point B and line CD, L E->FH is the perpendicular distance from point E to line FH.

[0048] L AB In fact, it is the distance from the first rotation center 120 of the pedal arm 100 to the pedal part 110, so L AB It can be set to a fixed value by default. When the stroke of the pedal arm 100 increases, L E->CD Decrease, L B->CD increases, and according to the definition formula of leverage ratio, the leverage ratio decreases.

[0049] Based on the above embodiment, point B of the pedal arm 100 and point E of the swing arm 200 are located on opposite sides respectively, point C of the pedal arm 100 is close to the side where point E is located, and point D of the swing arm 200 is close to the side where point B is located.

[0050] By placing point B of the pedal arm 100 and point E of the swing arm 200 on opposite sides, while allowing point C of the pedal arm 100 to be close to the side where point E is located and point D of the swing arm 200 to be close to the side where point B is located, the purpose of this design is to allow the pedal arm 100 and the swing arm 200 to form a movement logic with opposite movement directions.

[0051] Based on the above embodiment, points A, B and C of the pedal arm 100 form a triangular structure, and points A, B and C are respectively the three vertices of one triangular structure, and points D, H and E of the swing arm 200 form another triangular structure, and points D, H and E are respectively the three vertices of another triangular structure.

[0052] This design relies on the rational allocation of points A, B, C, D, H, and E, thereby forming a four-bar linkage structure that gradually reduces the leverage ratio. In this example, the lines connecting points A, B, and C form an obtuse triangle. Points B and A are located at opposite ends of the pedal arm 100, forming the vertices of the two acute angles of the triangle. Point C is located at the bottom of the pedal arm 100, forming the vertex of the obtuse angle of the triangle. The lines connecting points D, H, and E form another obtuse triangle. Points D and E are located at opposite ends of the swing arm 200, and point H is located in the middle of the swing arm 200. Points D and E form the vertices of the two acute angles of the other obtuse triangle, and point H forms the vertex of the obtuse angle of the other obtuse triangle.

[0053] like Figures 1 to 6 As shown, based on the above embodiment, a wire-controlled brake pedal includes a pedal mechanism that provides a variable lever ratio. In addition, the wire-controlled brake pedal also includes a spring 400, which is in contact with the force-bearing part of the swing arm 200.

[0054] Brake-by-wire (BBW) pedals abandon the traditional brake pedal design that relies on hydraulic systems or mechanical linkages to generate braking force. Instead, they use electronic signals to directly control the movement of the brake calipers. However, due to the lack of physical feedback, BBW pedals require additional pedal force simulation to simulate the traditional resistance felt by the driver when depressing the pedal.

[0055] The characteristic of the brake-by-wire pedal is that it can provide nonlinear pedal force. In a variable lever ratio pedal mechanism, when the stroke of the pedal arm 100 increases, the lever ratio decreases. The pedal force is defined as: F pedal =F spring / ratio,F pedal is the pedal force, F spring is the elastic force of the spring 400. According to the definition formula of the pedal force, when the stroke of the pedal arm 100 increases, the elastic force F spring It increases nonlinearly, and the lever ratio decreases, so the pedal force increases nonlinearly.

[0056] In the brake process of the line control brake pedal, the point A of the pedal arm 100 is stressed, at this time, the pedal arm 100 rotates around the point B, in the initial stage of the stroke, because the compression amount of the spring 400 is small, and the lever ratio is large, so the pedal force received is relatively small; with the increase of the stroke of the pedal arm 100, although the compression amount of the spring 400 does not increase significantly, that is, the increase of the elastic force is small, but the lever ratio gradually decreases at this time, at this time, the pedal force received increases significantly; in the later stage of the stroke of the pedal arm 100, the compression amount of the spring 400 increases, and the lever ratio is relatively small, in this stage, the pedal force increases sharply, and strong brake force feedback is provided to the driver.

[0057] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications will also change accordingly.

[0058] In addition, in the present application, the description such as "first", "second", "one" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can be explicitly or implicitly included at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0059] In the present application, unless otherwise specifically defined and limited, the terms "connection", "fixing" and the like should be understood in a broad sense, for example, "fixing" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically limited. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0060] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the fact that ordinary skilled in the art can realize it, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor is it within the scope of protection required by the present application.

Claims

1. A pedal mechanism providing a variable lever ratio, characterised in that, The pedal mechanism comprises: a pedal arm (100), two ends of the pedal arm (100) are respectively provided with a treading part (110) and a first rotation center (120); a swing arm (200), one end of the swing arm (200) is provided with a second rotation center (210); a connecting rod arm (300), one end of the connecting rod arm (300) is hinged with the pedal arm (100), and the other end of the connecting rod arm (300) is hinged with the other end of the swing arm (200); the pedal arm (100) is connected with the swing arm (200) through the connecting rod arm (300) to form a four-bar linkage structure, when the treading part (110) is treaded, the pedal arm (100) rotates around the first rotation center (120), and then drives the swing arm (200) to rotate around the second rotation center (210) through the connecting rod arm (300); the treading stroke of the pedal arm (100) determines the position of the connecting rod arm (300), and the position of the connecting rod arm (300) determines the lever ratio of the four-bar linkage structure; when the treading stroke of the pedal arm (100) increases, the lever ratio decreases.

2. A pedal mechanism providing a variable lever ratio as claimed in claim 1, characterised in that: the treading part (110) is provided as point A, the first rotation center (120) is provided as point B, the hinged point of the pedal arm (100) and the connecting rod arm (300) is provided as point C, the hinged point of the swing arm (200) and the connecting rod arm (300) is provided as point D, the second rotation center (210) is provided as point E, and a straight line passing through points C and D is provided as straight line CD; when the treading stroke of the pedal arm (100) increases, the perpendicular distance between point B and straight line CD increases, and the perpendicular distance between point E and straight line CD decreases, so that the lever ratio decreases.

3. A pedal mechanism providing a variable lever ratio as claimed in claim 2, characterised in that: the swing arm (200) is provided with a stress part for abutting with one end of a spring (400), and the stress part is provided as point H.

4. A pedal mechanism providing a variable lever ratio as claimed in claim 3, characterised in that: when point A of the pedal arm (100) is pressed, point A of the pedal arm (100) rotates around point B together with point C, point D of the swing arm (200) rotates around point E together with point H, and the rotating direction of the pedal arm (100) is opposite to that of the swing arm (200).

5. A pedal mechanism providing a variable lever ratio as claimed in claim 2, characterised in that: point B of the pedal arm (100) and point E of the swing arm (200) are respectively located on opposite sides, point C of the pedal arm (100) is close to the side where point E is located, and point D of the swing arm (200) is close to the side where point B is located.

6. A pedal mechanism providing a variable lever ratio as claimed in claim 3, characterised in that: point A, point B and point C of the pedal arm (100) form a triangular structure, and point A, point B and point C are respectively three vertices of the triangular structure, and point D, point H and point E of the swing arm (200) form another triangular structure, and point D, point H and point E are respectively three vertices of the other triangular structure.

7. A brake-by-wire pedal characterized by, The pedal mechanism comprises the pedal mechanism of any one of claims 1-6.

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