A vehicle brake control device

Abstract

This application discloses a vehicle braking control device, including a drum frame, a leading shoe, a trailing shoe, and a cam. One end of the leading shoe and the trailing shoe are respectively provided with a first roller and a second roller that cooperate with the cam, and the other end cooperates with a pivot member, allowing the leading shoe and the trailing shoe to swing about a fixed axis. When braking, the cam rotates, pushing the first roller and the second roller outward, causing the leading shoe and the trailing shoe to swing and expand outward, resulting in friction between the leading shoe and the trailing shoe and the drum frame to achieve braking. The outer contour of the cam includes an asymmetrical S-shaped curve that makes the first roller and the second roller move equal distances or the leading shoe and the trailing shoe rotate equal angles during the swinging process. This application can achieve equal outward rotation angles (or displacements) of the leading shoe and the trailing shoe on both sides during the swinging process, thereby enabling the friction pads to achieve the best friction effect and making the brake pads open more forcefully, resulting in lighter and more sensitive operation.

Description

Technical Field

[0001] This application relates to the technical field of vehicle braking control systems or components thereof, and in particular to a vehicle braking control device. Background Technology

[0002] Among vehicle braking control devices, the leading-follower drum brake is a common automotive braking system. It applies force to the leading and following shoes or drum to brake the wheels and stop the vehicle. Its powerful braking force, long service life and wide adaptability are highly regarded.

[0003] The braking performance of a vehicle's braking control system is a crucial factor in ensuring vehicle stability and an important consideration during vehicle design. Currently, with follower shoe drum brakes, when the driver depresses the brake pedal, hydraulic fluid from the master cylinder flows through the oil lines into the wheel cylinders, increasing the fluid pressure. This pressure, via a cam, pushes the brake shoes outward around their support pins, pressing them against the rotating brake drum, thus generating braking torque to slow the vehicle down or bring it to a stop.

[0004] In a lead-follower drum brake, the cam is the key component that converts the translational motion of the external push rod into rotation and applies torque to the rollers, causing the lead and follower shoes to rotate. Therefore, studying the rotational state between the cam and the rollers is crucial. Currently used cams, when rotating, cause the rollers connected to one end of the lead and follower shoes to rotate outwards due to the cam's force, while the other end rotates around a fixed axis. The angles (or displacements) of the two rollers are unequal, and the displacements of the lead and follower shoes are also unequal (this can be termed "asymmetric opening"), resulting in the friction linings not achieving optimal friction. Furthermore, most current oscillating follower drum brakes roughly employ centrally symmetrical cams of translational follower types, further leading to asymmetric opening of the oscillating brake shoes (i.e., lead and follower shoes). Utility Model Content

[0005] To solve the above-mentioned technical problems, the purpose of this utility model is to provide a vehicle braking control device in which the two leading hooves have equal angles (or displacements) of outward rotation from the hooves.

[0006] The technical solution provided by this utility model is as follows: A vehicle braking control device includes a drum frame, a leading shoe, a trailing shoe, and a cam. One end of the leading shoe and the trailing shoe are respectively provided with a first roller and a second roller that cooperate with the cam, and the other end cooperates with a pivot member to enable the leading shoe and the trailing shoe to swing about a fixed axis. When braking, the cam rotates and pushes the first roller and the second roller to move outward, causing the leading shoe and the trailing shoe to swing and expand outward, so that the leading shoe and the trailing shoe rub against the drum frame to achieve braking. The outer contour of the cam includes an asymmetrical S-shaped curve in which the first roller and the second roller move equal distances or the leading shoe and the trailing shoe rotate equal angles during the swinging process.

[0007] Preferably, the asymmetric S-curve is obtained by obtaining the relationship between the cam rotation angle and the moving distance of the first roller / second roller or the relationship between the cam rotation angle and the rotation angle of the leading shoe / following shoe according to the required transmission ratio characteristics, and then obtaining it through the inverse solution method based on this relationship.

[0008] Preferably, the transmission ratio characteristic is constant velocity motion, constant acceleration, constant deceleration, cosine acceleration, sine acceleration, or a fifth-order polynomial.

[0009] Preferably, a support slot is provided below the drum frame, the support slot is used to install a pivot pin, the pivot pin forms a pivot member to cooperate with the leading shoe and the trailing shoe so that the leading shoe and the trailing shoe can swing around the pivot pin fixed axis.

[0010] Preferably, the leading shoe further includes a first drum brake caliper and a first friction liner located outside the first drum brake caliper. The first roller is mounted on one end of the first drum brake caliper, and the other end of the first drum brake caliper is provided with a first incomplete semicircular groove. The trailing shoe further includes a second drum brake caliper and a second friction liner located outside the second drum brake caliper. The second roller is mounted on one end of the second drum brake caliper, and the other end of the second drum brake caliper is provided with a second incomplete semicircular groove. The pivot pin includes a pin shaft. The first incomplete semicircular groove and the second incomplete semicircular groove are coaxially clearance-fitted with the pin shaft, so that the leading shoe and the trailing shoe can swing around the pivot pin.

[0011] Preferably, the outer side of the first drum brake caliper is provided with a first arc-shaped notch for installing the first friction liner, and the outer side of the second drum brake caliper is provided with a second arc-shaped notch for installing the second friction liner.

[0012] Preferably, the cam includes a cam body and a rotating shaft located on the back of the cam body. A through hole is provided above the drum frame, and the rotating shaft is accommodated in the through hole and has a clearance fit with the through hole. The two sides of the cam body include a first curved surface and a second curved surface, and the axial projection of the first curved surface and the second curved surface forms the outer contour line of the cam.

[0013] Preferably, a boss is provided between the cam body and the rotating shaft, and the size of the boss is larger than the size of the through hole.

[0014] Compared to existing technologies, the vehicle braking control device of this utility model uses an asymmetrical S-shaped curve, including the outer contour of the cam, to ensure that the first roller and the second roller move equal distances or that the leading shoe and the trailing shoe rotate equal angles during the swinging process of the leading shoe and the trailing shoe. Therefore, it can achieve equal outward rotation angles (or displacements) of the leading shoe and the trailing shoe on both sides during the swinging process of the leading shoe and the trailing shoe, thereby reducing sudden acceleration, preventing flexible or rigid impacts, reducing wear on the cam and rollers, achieving the best friction effect for the friction lining, and utilizing the actuation effect to make the brake pads open more powerfully, making it easier and more responsive to use. The cam has a larger torsional opening, higher strength, and improved safety performance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a perspective view of the vehicle braking control device according to an embodiment of the present utility model; Figure 2 for Figure 1 Front view of the vehicle braking control device shown; Figure 3 for Figure 1 A perspective view of the drum frame in the vehicle braking control device shown. Figure 4 for Figure 1 A three-dimensional view of the leading shoe in the vehicle braking control device shown. Figure 5 for Figure 1 A three-dimensional view of the brake shoe in the vehicle braking control device shown. Figure 6 for Figure 1 A three-dimensional view of the pivot pin in the vehicle braking control device shown. Figure 7 for Figure 1 A three-dimensional view of the cam in the vehicle braking control device shown. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0019] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0021] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0022] like Figures 1 to 7 As shown, this utility model embodiment provides a vehicle braking control device, including a drum frame 1, a leading shoe 2, a trailing shoe 3, a cam 3, and a pivot pin 5.

[0023] like Figure 3 As shown, in this embodiment, the upper part of the drum frame 1 is provided with a through hole 101 for mounting the rotating shaft of the cam 3, and the lower part of the drum frame 1 is provided with a support slot 102 for mounting the pivot pin 5.

[0024] like Figure 4 As shown, in this embodiment, the leading shoe 2 consists of a first drum brake caliper 203, a first friction liner 202, and a first roller 201 that cooperates with the cam 3. The first drum brake caliper 203 is provided with a first limiting support through hole 206 for limiting and rolling the first roller 201. The first drum brake caliper 203 is provided with a first incomplete semi-circular slot 204 for cooperating with the pivot pin 5, so that the first drum brake caliper 203 can rotate around the pivot pin 5 after being subjected to force. The first drum brake caliper 203 has a first arc-shaped retaining slot 205 for installing the first friction liner 202.

[0025] like Figure 5 As shown, in this embodiment, the brake shoe 4 consists of a second drum brake caliper 403, a second friction liner 402, and a second roller 401 that cooperates with the cam 3. The second drum brake caliper 403 has a second limiting support through hole 406 for limiting and rolling the second roller 401, and a second non-fully semi-circular slot 404 for cooperating with the pivot pin 5, so that the second drum brake caliper 403 can rotate around the pivot pin 5 after being subjected to force. The second drum brake caliper 403 has a second arc-shaped bayonet 405 for mounting the second friction liner 402.

[0026] like Figure 6 As shown, in this embodiment, the pivot pin 5 is used to limit the leading shoe 2 and the trailing shoe 4 at both ends. It is a shaft-type part with a pin 501, which is coaxially clearance-fitted with the first incomplete semicircular slot 204 of the leading shoe 2 and the second incomplete semicircular slot 404 of the trailing shoe 4 to form a pivot, allowing the leading shoe 2 and the trailing shoe 4 to rotate around the pivot pin 5. Of course, in other embodiments, the pivot pin may not be provided, and other structures (such as a protruding shaft set on the drum frame) may be used, as long as a pivot can be formed to allow the leading shoe and the trailing shoe to swing around a fixed axis.

[0027] like Figure 7 As shown, in this embodiment, the cam 3 is an asymmetrical S-shaped curve cam, including a cam body 300. The back of the cam body 300 has a boss 301, which is then connected to a rotating shaft 302. The rotating shaft 302 engages with the through hole 101 of the drum frame 1 via a clearance fit, allowing the cam 3 to rotate within the through hole 101. The size of the boss 301 is larger than the size of the through hole 101 to isolate the cam body 300 from the drum frame 1.

[0028] The cam body has a first curved surface 303 and a second curved surface 304 on both sides. The axial projection of the first curved surface 303 and the second curved surface 304 forms the outer contour line of the cam. This outer contour line includes an asymmetrical S-shaped curve that makes the moving distance of the first roller 201 and the second roller 401 equal or the rotation angle of the lead shoe 2 and the follower shoe 4 equal during the swinging process. It should be noted that the moving distance of the first roller 201 and the second roller 401 and the rotation angle of the lead shoe 2 and the follower shoe 4 are two different characterizing parameters, but the final effect is the same. Therefore, this specification sometimes only selects one of them for description. The two ends of the first curved surface 303 and the second curved surface 304 are also provided with chamfers (such as...). Figure 7 As shown, the two ends of the second curved surface 304 are respectively provided with a first chamfer 305 and a second chamfer 306.

[0029] The asymmetric S-curve is derived by obtaining the relationship between the cam rotation angle and the travel distance of the first / second roller, or the relationship between the cam rotation angle and the rotation angle of the leading / following shoe, based on the required transmission ratio characteristics. This relationship is then used inverse kinematics to obtain the characteristic. Since the leading and following shoes are oscillating components, the resulting profile is an asymmetric S-curve. This transmission ratio characteristic can be constant velocity motion, constant acceleration, constant deceleration, cosine acceleration, sine acceleration, or a fifth-order polynomial (and other characteristics, depending on design requirements).

[0030] In use, the aforementioned vehicle braking control device has a brake chamber (or brake cylinder) fixedly mounted on the top of the drum bracket 1. The brake chamber converts gas pressure into mechanical force, pushing the chamber push rod forward. The adjusting arm and the rotating shaft 302 of the cam 3 convert the translational displacement of the push rod into rotational displacement, causing the cam 3 to rotate and thus apply force to the first roller 201 and the second roller 401. During braking, the starting cam 3 and the first roller 201 and the second roller 401 are rigidly connected and move together by the cooperation of the first curved surface 303 and the second curved surface 304. As cam 3 rotates, the first roller 201 and the second roller 401 begin to rotate along the corresponding curved surfaces, simultaneously driving the first drum brake caliper 203 and the second drum brake caliper 403 to expand outwards, and rotating around the pivot pin 5 as a fixed axis. Due to the specific asymmetrical S-shaped curves on both sides of cam 3 (an asymmetrical S-shaped curve that makes the first roller and the second roller move equal distances or the leading shoe and the following shoe rotate equal angles during the swing of the leading shoe and the following shoe), when cam 3 rotates through a certain angle, the leading shoe 2 and the following shoe 4 on both sides can achieve equal displacements in their outward expansion movement, and there will be no situation where different displacements lead to large differences in torque. This achieves the purpose of deceleration by generating a counter-torque through the mutual friction between the first friction lining 202, the second friction lining 402, and the outer brake drum. It should be noted that in this embodiment, the first curved surface 303 and the second curved surface 304 of the cam 3 can achieve a constant transmission ratio. When the cam 3 rotates, the displacement (angle) of the leading shoe 2 and the trailing shoe 4 can increase linearly with a certain transmission ratio (at this time, the transmission ratio is constant), that is, to achieve smoother and gentler braking. In the later stage of the braking stroke, a smaller force can be used to obtain a larger torque, or when the cam 3 rotates rapidly, the leading shoe 2 and the trailing shoe 4 expand outward faster to meet the needs of emergency braking. When the maximum rotation angle of the cam 3 is reached, the first roller 201 and the second roller 401 can be well limited by the limiting effect and will not be misaligned and disengaged. After the braking operation is completed, the cam 3 begins to rotate in the opposite direction to reset, and at the same time, the leading shoe 2 and the trailing shoe 4 also begin to reset around the pivot pin 5, and the friction pads on both sides also disengage from the outer brake drum. Finally, it returns to its original position, ready for the next braking operation.

[0031] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A vehicle braking control device, characterized in that, The device includes a drum frame, a leading shoe, a trailing shoe, and a cam. One end of the leading shoe and the trailing shoe are respectively provided with a first roller and a second roller that cooperate with the cam, and the other end cooperates with a pivot to enable the leading shoe and the trailing shoe to swing about a fixed axis. When braking, the cam rotates and pushes the first roller and the second roller to move outward, causing the leading shoe and the trailing shoe to swing and expand outward, so that the leading shoe and the trailing shoe rub against the drum frame to achieve braking. The outer contour of the cam includes an asymmetrical S-shaped curve in which the first roller and the second roller move equal distances or the leading shoe and the trailing shoe rotate equal angles during the swinging process.

2. The vehicle braking control device as described in claim 1, characterized in that, The asymmetric S-curve is obtained by determining the relationship between the cam rotation angle and the moving distance of the first / second roller or the cam rotation angle and the rotation angle of the leading / following shoe based on the required transmission ratio characteristics, and then derived by inverse kinematics based on this relationship.

3. The vehicle braking control device as described in claim 2, characterized in that, The transmission ratio characteristic is constant velocity motion, constant acceleration, constant deceleration, cosine acceleration, sine acceleration, or a fifth-order polynomial.

4. The vehicle braking control device as described in claim 1, 2, or 3, characterized in that, The drum frame is provided with a support slot at the bottom, which is used to install a pivot pin. The pivot pin forms a pivot to cooperate with the leading shoe and the trailing shoe so that the leading shoe and the trailing shoe can swing around the pivot pin's fixed axis.

5. The vehicle braking control device as described in claim 4, characterized in that, The leading shoe also includes a first drum brake caliper and a first friction liner located outside the first drum brake caliper. The first roller is mounted on one end of the first drum brake caliper, and the other end of the first drum brake caliper is provided with a first incomplete semicircular groove. The trailing shoe also includes a second drum brake caliper and a second friction liner located outside the second drum brake caliper. The second roller is mounted on one end of the second drum brake caliper, and the other end of the second drum brake caliper is provided with a second incomplete semicircular groove. The pivot pin includes a pin shaft. The first incomplete semicircular groove and the second incomplete semicircular groove are coaxially and clearance-fitted with the pin shaft, so that the leading shoe and the trailing shoe can swing around the pivot pin.

6. The vehicle braking control device as described in claim 5, characterized in that, The first drum brake caliper has a first arc-shaped notch on its outer side for installing the first friction liner, and the second drum brake caliper has a second arc-shaped notch on its outer side for installing the second friction liner.

7. The vehicle braking control device as described in claim 1, 2, or 3, characterized in that, The cam includes a cam body and a rotating shaft located on the back of the cam body. A through hole is provided above the drum frame, and the rotating shaft is accommodated in the through hole and has a clearance fit with the through hole. The two sides of the cam body include a first curved surface and a second curved surface, and the axial projection of the first curved surface and the second curved surface forms the outer contour line of the cam.

8. The vehicle braking control device as described in claim 7, characterized in that, A boss is also provided between the cam body and the rotating shaft, and the size of the boss is larger than the size of the through hole.

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