A variable lever ratio brake pedal

Abstract

The present invention relates to a variable lever ratio brake pedal, and belongs to the technical field of automobile brake systems. The variable lever ratio brake pedal of the present invention comprises a pedal bracket, a first-stage pedal arm, a second-stage pedal arm, a T-shaped pin, a guide block and a brittle gasket. When the booster fails, the variable lever ratio brake pedal of the present invention automatically adjusts the lever ratio according to the design values ​​of the first-stage pedal arm and the second-stage pedal arm, thereby increasing the braking force, shortening the braking distance and reducing safety hazards. Moreover, the brake pedal of the present invention adopts a purely mechanical trigger structure, which is simple and reliable in structure, and can be used repeatedly after replacing the brittle gasket.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile braking systems, and in particular to a variable lever ratio brake pedal. Background Art

[0002] The brake pedal, as the name implies, is a pedal that limits power, that is, the pedal of the foot brake (service brake). The brake pedal is used to slow down and stop the car. It is one of the five major control parts of car driving. The frequency of use is very high. How the driver controls it directly affects the safety of car driving.

[0003] Figure 1-2 A brake pedal with a fixed lever ratio in the prior art is shown, wherein the brake pedal arm 1 is an integral structure, welded to the shaft sleeve 2 and connected to the pedal bracket 5 through the shaft 3 and the shaft bushing 4. When the boost fails (for example, when there is a vacuum leak or electrical abnormality), the driver steps on the pedal surface 101, and the pedal arm can only move around the shaft 3, and amplifies the driver's pedaling force with a fixed lever ratio i=b / a (for example, b=3a, then i=3), and pushes the booster push rod connected by the booster push rod hole 102 to increase the brake hydraulic pressure and implement braking.

[0004] When the power assist fails, since the brake pedal lever ratio cannot be adjusted, the braking distance is too long (normally about 40m for a speed of 100km / h, and about 130m when the power assist fails), and the deceleration is small (normally about 1g, and about 0.3g when it fails). It feels like the pedal cannot be pressed, which may lead to serious personal and property safety accidents.

[0005] In the prior art, there are many brake pedals with variable lever ratios. CN110588602A discloses a brake pedal with variable lever ratio, wherein an adjusting screw is provided at the hinge between the brake pedal arm and the booster push rod, a screw sleeve is mounted on the adjusting screw, and two locking nuts are screwed, and one end of the booster push rod is hinged with the screw sleeve. The brake pedal needs to adjust the lever ratio by loosening the locking nut, and when the vacuum booster cannot be triggered normally, the lever ratio cannot be adjusted automatically. CN206954209U discloses an anti-intrusion variable lever ratio brake pedal, wherein when the driver steps on the pedal, the pedal arm rotates around the first rotating shaft, and through the transmission of the two force rods, the swing rod is driven to rotate around the second rotating shaft, and the swing rod is connected to the booster push rod through the third pin shaft, and the pedal force is transmitted to the booster through the above transmission mechanism. The brake pedal can realize the anti-intrusion function when the car is in a frontal collision, reducing the impact of the pedal on the driver's lower limbs when the vehicle collides, and does not involve the problem that the vacuum booster is not triggered at a preset pressure.

[0006] When the booster fails, the braking distance will be too long, which poses a major safety hazard. Therefore, it is necessary to provide a brake pedal that automatically changes the lever ratio when the booster fails. Summary of the invention

[0007] In order to solve the above technical problems existing in the prior art, an object of the present invention is to provide a variable lever ratio brake pedal.

[0008] The variable lever ratio brake pedal of the present invention comprises a pedal bracket, a first-stage pedal arm, a second-stage pedal arm, a T-shaped pin shaft, a guide block and a brittle gasket; the first-stage pedal arm comprises two symmetrically arranged arm plates, and the arm plates are provided with a first rotating shaft hole, a pin shaft hole and a second rotating shaft hole in sequence from top to bottom; a rotating shaft sleeve is installed in the first rotating shaft hole of the arm plate, and a rotating shaft bushing is installed on the rotating shaft sleeves of the two arm plates, and the two arm plates are fixed to the pedal bracket rotatably around the first rotating shaft through the first rotating shaft bushing; the pin shaft rod of the T-shaped pin shaft is installed in the pin shaft holes of the two arm plates, and the guide block is sleeved on the middle vertical rod of the T-shaped pin shaft, and a coil spring is also sleeved on the middle vertical rod of the T-shaped pin shaft, and the coil spring The spring is located between the bottom of the guide block and the pin rod of the T-pin shaft; the brittle gasket is locked to the upper end of the guide block by a nut that cooperates with the guide block, and the middle vertical rod of the T-pin shaft contacts the brittle gasket, and the two side walls of the guide block are clamped and fixed by the two arm plates; the upper part of the second-stage pedal arm is provided with a second shaft through hole and a booster push rod hole from top to bottom, and the first-stage pedal arm and the second-stage pedal arm are connected and fixed by a second shaft passing through the second shaft hole and the second shaft through hole; the upper end surface of the second-stage pedal arm is a curved surface with a notch, and before the adjustment lever ratio is triggered, the pin rod of the T-pin shaft is stuck in the notch of the curved surface of the second-stage pedal arm, and the T-pin shaft is adjacent to but not in contact with the pedal bracket.

[0009] The curved surface of the upper end face of the second-stage pedal arm includes an equidistant curved surface segment with a constant distance to the second rotating shaft through hole, and the distance from the equidistant curved surface segment to the second rotating shaft through hole is greater than the distance from the notch to the second rotating shaft through hole.

[0010] Among them, when the power assist fails, when the pedaling force applied by the driver is greater than the preset force value, the secondary pedal arm rotates around the axis of the booster push rod hole and pushes the middle vertical rod of the T-pin shaft through the curved surface of the secondary pedal arm to break through the brittle gasket.

[0011] Wherein, after the brake pedal triggers the adjustment lever ratio, the pin shaft rod of the T-shaped pin shaft contacts the pedal bracket, and the pin shaft rod of the T-shaped pin shaft is located on the equidistant curved surface segment.

[0012] Among them, the preset force value is 400N-500N, and the preset force value can be further adjusted by modifying the thickness and material of the brittle gasket.

[0013] Among them, the distance from the first rotating shaft to the center of gravity of the pedal surface of the pedal arm is b, and the distance from the first rotating shaft to the booster push rod hole is a, then the lever ratio of the brake pedal before the lever ratio adjustment is triggered is i=b / a.

[0014] Among them, the distance from the second rotating shaft to the center of gravity of the pedal surface of the pedal arm is d, and the distance from the second rotating shaft to the booster push rod hole is c, then the lever ratio of the brake pedal after triggering the adjustment lever ratio is i=d / c.

[0015] Wherein, the rotating shaft sleeve is welded in the first rotating shaft hole of the arm plate.

[0016] The guide block comprises a base with two side wall surfaces and a sleeve located on the base, and a through hole for accommodating the middle vertical rod is arranged in the base and the sleeve.

[0017] Wherein, a groove for accommodating the coil spring is arranged on the lower end surface of the base.

[0018] Compared with the prior art, the variable lever ratio brake pedal of the present invention has the following beneficial effects:

[0019] When the power assist fails, the variable lever ratio brake pedal of the present invention automatically adjusts the lever ratio according to the design values ​​of the first-stage pedal arm and the second-stage pedal arm, thereby increasing the braking force, shortening the braking distance, and reducing safety hazards. Moreover, the brake pedal of the present invention adopts a purely mechanical trigger structure, which is simple and reliable in structure and can be used repeatedly after replacing the brittle gasket. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional structural diagram of a brake pedal with a fixed lever ratio in the prior art.

[0021] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure along the AA direction.

[0022] Figure 3 It is a three-dimensional structural diagram of the variable lever ratio brake pedal of the present invention.

[0023] Figure 4 It is a three-dimensional structural diagram of the pedal arm assembly in the variable lever ratio brake pedal of the present invention.

[0024] Figure 5 It is an exploded view of the pedal arm assembly in the variable lever ratio brake pedal of the present invention.

[0025] Figure 6 It is a schematic diagram of the pedal trajectory state when the variable lever ratio brake pedal of the present invention is not triggered.

[0026] Figure 7 for Figure 6 Schematic diagram of the cross-sectional structure along the BB direction.

[0027] Figure 8 Schematic diagram of the state of the end of the secondary pedal arm before triggering.

[0028] Fig. 9 It is a schematic diagram of the pedal state of the variable lever ratio brake pedal triggering process of the present invention.

[0029] Fig.10 It is a schematic diagram of the state of the end of the secondary pedal arm after being triggered.

[0030] Fig.11 It is a schematic diagram of the pedal trajectory state after the variable lever ratio brake pedal of the present invention is triggered.

[0031] Fig.12 for Fig.11 Schematic diagram of the cross-sectional structure along the CC direction. DETAILED DESCRIPTION

[0032] The variable lever ratio brake pedal of the present invention will be further described below in conjunction with specific embodiments to help those skilled in the art to have a more complete, accurate and in-depth understanding of the technical solution of the present invention.

[0033] Example 1

[0034] In view of the technical problem that when the current brake system fails to assist (feeling that the pedal cannot be pressed), the braking distance is too long and the deceleration is small, which easily induces major safety accidents, this embodiment provides a variable lever ratio brake pedal, such as Figure 3-5As shown, it includes a pedal bracket 5, a first-stage pedal arm 6, a second-stage pedal arm 7, a T-shaped pin 8, a guide block 10 and a brittle gasket 11. The first-stage pedal arm 6 includes two symmetrically arranged arm plates, and the arm plates are provided with a first shaft hole 61, a pin hole 62 and a second shaft hole 63 in sequence from top to bottom. A shaft sleeve 2 is assembled (for example, welded) in the first shaft hole 61 of the arm plate, and a shaft bushing 4 is assembled on the shaft sleeves 2 of the two arm plates, and the two arm plates are fixed to the pedal bracket 5 rotatably around the first shaft 3 by passing through the first shaft 3 of the shaft bushing 4. The pin shaft rod of the T-shaped pin shaft 8 is installed in the pin shaft holes 62 of the two arm plates, and the guide block 10 is sleeved on the middle vertical rod of the T-shaped pin shaft 8, and a coil spring 9 is also sleeved on the middle vertical rod of the T-shaped pin shaft 8, and the coil spring 9 is located between the bottom of the guide block 10 and the pin shaft rod of the T-shaped pin shaft 8. The brittle gasket 11 is locked to the upper end of the guide block 10 by a nut 12 matched with the guide block 10, and the middle vertical rod of the T-shaped pin 8 contacts the brittle gasket 11, and the two side walls of the guide block 10 are clamped and fixed by the two arm plates. The upper part of the second-stage pedal arm 7 is provided with a second shaft through hole 71 and a booster push rod hole 102 in sequence from top to bottom, and the first-stage pedal arm 6 and the second-stage pedal arm 7 are connected and fixed by the second shaft 13 passing through the second shaft hole 63 and the second shaft through hole 71. The upper end surface of the second-stage pedal arm 7 is a curved surface 107 with a notch, and the pin rod of the T-shaped pin 8 is stuck on the notch of the curved surface 107 of the second-stage pedal arm 7, and the T-shaped pin 8 is adjacent to the pedal bracket 5 but not in contact. In this embodiment, the guide block 10 includes a base with two side wall surfaces and a sleeve located on the base, the base and the sleeve are provided with through holes for accommodating the middle vertical rod, and a groove for accommodating the coil spring is provided on the lower end surface of the base.

[0035] like Figure 6-12 As shown, when the driver steps on the pedal surface 101 when the power assist fails, the pedal arm assembly first moves around the first rotation axis 3 and amplifies the driver's pedal force with a fixed lever ratio i=b / a (e.g. b=3a, i=3). Figure 6 The initial position 103 of the secondary pedal arm 7 moves to a preset force value (e.g., 450N) without assistance and the variable lever brake pedal is not triggered. When the pedal is difficult to continue to be stepped on, as the driver's pedal force further increases and exceeds the preset force value (e.g., 450N), the secondary pedal arm 7 rotates around the axis of the booster push rod hole 102 and passes through the curved surface 107 (e.g., Figure 8As shown in FIG. 1 , the middle vertical rod of the T-shaped pin 8 is pushed to break through the brittle gasket 11, thereby driving the T-shaped pin 8 and the first pedal arm 6 to rotate in the opposite direction around the first rotating shaft 3 until the T-shaped pin contacts the pedal bracket 5. In this process, the pedal arm is Figure 6 When the position 104 is in the unassisted state and the variable lever ratio mechanism is not triggered, it moves to the triggered position 106. The driver's pedaling force continues to increase, and the secondary pedal arm 7 tends to rotate around the axis of the booster push rod hole 102, but the T-pin 8 is blocked by the pedal bracket 5. The T-pin 8 is connected to the secondary pedal arm 7 through the curve 107 at the end of the secondary pedal arm 7, and the secondary pedal arm 7 is connected to the primary pedal arm 6 through the second rotating shaft 13, so that the primary pedal arm 6 will not continue to rotate in the reverse direction. After that, the secondary pedal arm 7 can only rotate around the secondary pedal arm rotating shaft 13, and as shown in Figure 9, the distance e from the secondary pedal arm end curve 107 that contacts the T-pin to the second rotating shaft 13 is equal, so that when the secondary pedal arm 7 continues to rotate around the second rotating shaft 13, the T-pin 8 and the primary pedal arm 6 will not be linked. After that, the pedal increases the driver's pedaling force with a lever ratio of i=d / c (for example, c=2a / 5, d=12a / 5, then i=6), and pushes the booster push rod connected to the booster push rod hole 102 to continue to increase the brake fluid pressure, thus implementing stronger braking. Fig.11 and 12 shown.

[0036] The variable lever ratio brake pedal of this embodiment can automatically increase the brake pedal lever ratio by mechanical means when the boost fails, thereby increasing the braking force and shortening the braking distance under the same pedal force. The brake pedal structure of this embodiment adopts a purely mechanical trigger structure, which is simple and reliable, and can be used repeatedly after replacing the brittle gasket 11.

[0037] For ordinary technicians in this field, the specific embodiments are only illustrative descriptions of the present invention. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A variable lever ratio brake pedal, characterized in that: The pedal bracket comprises a pedal arm, a first-stage pedal arm, a second-stage pedal arm, a T-shaped pin, a guide block and a brittle gasket; the first-stage pedal arm comprises two symmetrically arranged arm plates, the arm plates being provided with a first shaft hole, a pin hole and a second shaft hole in sequence from top to bottom; a shaft sleeve is installed in the first shaft hole of the arm plate, and shaft bushings are installed on the shaft sleeves of the two arm plates, and the two arm plates are fixed to the pedal bracket rotatably around the first shaft through a first shaft passing through the shaft bushing; the T-shaped pin The pin shaft rod is installed in the pin shaft holes of the two arm plates, and the guide block is sleeved on the middle vertical rod of the T-shaped pin shaft, and a coil spring is sleeved on the middle vertical rod of the T-shaped pin shaft, and the coil spring is located between the bottom of the guide block and the pin shaft rod of the T-shaped pin shaft; the brittle gasket is locked to the upper end of the guide block by a nut matched with the guide block, and the middle vertical rod of the T-shaped pin shaft contacts the brittle gasket, and the two side walls of the guide block are clamped and fixed by the two arm plates; the second-stage pedal The upper part of the plate arm is provided with a second shaft through hole and a booster push rod hole in sequence from top to bottom, the first-stage pedal arm and the second-stage pedal arm are connected and fixed by a second shaft passing through the second shaft hole and the second shaft through hole; the upper end surface of the second-stage pedal arm is a curved surface with a clamping notch, and before the adjustment lever ratio is triggered, the pin shaft rod of the T-shaped pin shaft is clamped in the clamping notch of the curved surface of the second-stage pedal arm, and the T-shaped pin shaft is adjacent to the pedal bracket but not in contact; the curved surface of the upper end surface of the second-stage pedal arm includes a notch to the second shaft through hole. An equidistant curved surface segment with a constant hole distance, and the distance from the equidistant curved surface segment to the second rotating shaft through hole is greater than the distance from the card notch to the second rotating shaft through hole; when the power assist fails, the pedaling force applied by the driver is greater than the preset force value, the secondary pedal arm rotates around the axis of the booster push rod hole and pushes the middle vertical rod of the T-type pin shaft through the curved surface of the secondary pedal arm to break through the brittle gasket; after the brake pedal triggers the adjustment lever ratio, the pin shaft rod of the T-type pin shaft contacts the pedal bracket, and the pin shaft rod of the T-type pin shaft is located on the equidistant curved surface segment.

2. The variable lever ratio brake pedal according to claim 1, characterized in that: The preset force value is 400N-500N, and the preset force value can be adjusted by modifying the thickness and material of the brittle gasket.

3. The variable lever ratio brake pedal according to claim 1, characterized in that: The distance from the first rotating shaft to the center of gravity of the pedal surface of the pedal arm is b, and the distance from the first rotating shaft to the booster push rod hole is a. Then the lever ratio of the brake pedal before the lever ratio adjustment is triggered is i=b / a.

4. The variable lever ratio brake pedal according to claim 1, characterized in that: The distance from the second rotating shaft to the center of gravity of the pedal surface of the pedal arm is d, and the distance from the second rotating shaft to the booster push rod hole is c, then the lever ratio of the brake pedal after triggering the adjustment lever ratio is i=d / c.

5. The variable lever ratio brake pedal according to claim 1, characterized in that: The rotating shaft sleeve is welded in the first rotating shaft hole of the arm plate.

6. The variable lever ratio brake pedal according to claim 1, characterized in that: The guide block comprises a base with two side wall surfaces and a sleeve located on the base. Through holes for accommodating the middle vertical rod are arranged in the base and the sleeve.

7. The variable lever ratio brake pedal according to claim 6, characterized in that: A groove for accommodating the coil spring is arranged on the lower end surface of the base.

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