JP2005532518A - High performance drum brake assembly for brake systems for AUTOMOTION vehicles - Google Patents

Abstract

A high performance drum brake system can substantially increase the brake output torque relative to the hydraulic input pressure or reduce the pipeline pressure required to increase the current torque rate. The brake device comprises a new lever (17) that rotates on the leading shoe (19) web. One end of the lever is in contact with the wheel cylinder piston (11), and the other end is in contact with the strut (15). The lever is in contact with the rotating cylinder piston instead of the leading shoe web and receives input from the pressurized wheel cylinder. The lever rotates on the axis of rotation (18) and pushes the strut. The trailing shoe (3) receives two inputs, the force from the wheel cylinder and the force from the strut. Both the input of the wheel cylinder and the reaction force of the strut device (15) act on the rotating shaft (18). As a result, approximately twice the force acts on the leading shoe.

Description

Detailed Description of the Invention

〔Technical field〕
The present invention relates generally to automotive technology. More specifically, the present invention mainly relates to an automobile brake system. In particular, the present invention relates to a new drum brake assembly structure for vehicle brake means.

  At the beginning of the following description, it will be understood that the following description is merely illustrative of certain forms of the invention. However, it should be noted that such specific forms are only given as examples and do not limit the scope of the present invention.

[Background Technology]
The description of the prior art gives detailed information about the prior art, methods, processes and information about the systems known in the prior art, from which it can be understood that there are drawbacks in the related art, It will be appreciated that the object of the invention is to solve or overcome the problems associated with the prior art. This forms an important feature and purpose of the invention.

  As engine engineering continues to improve, roads improve, economic speed increases, and statutory / regulatory requirements tighten, there is a need to develop safer braking systems that meet this requirement. In addition, in order to cope with the increase in vehicle weight and speed, and to provide improved braking performance, hydraulic drum brake assemblies have increased in size from φ7 to φ12 so far. And applied to practical vehicles.

  In an effort to provide a good brake system, better friction material and larger diameter drum brakes were applied primarily to the rear equipment. The emphasis of the above proposal is on brake squeak, consistency of brake lining performance, grabbing slope, early morning sharpness, and reduced braking force (high fade), high lining wear, and increased drive system.

  In addition to the increased costs associated with the above proposals, it is always a problem to accommodate larger brakes within the size of the wheels that can be used. To address the above problems, the latest structures have been studied and new proposals that can overcome the above problems have been presented.

  In addition to increasing wheel cylinder and brake diameters, Duo Servo structures have been developed to improve service and parking brake performance to a level that meets demands. In the structure of the duo servo, the sensitivity corresponding to the change of the friction level is limited.

  In addition to the proportional increase in wheel cylinder and brake diameters to meet the requirements, the problem of increased demand for actuation and related issues of packaging issues caused very large problems. It is. A reduction in pedal effort has also been achieved in a given brake system by increasing the friction level or miniaturizing the master cylinder (despite the impact of the pedal stroke).

  To address the above issues, the brake output torque required for a specific hydraulic input pressure can be increased sufficiently, reducing the pipeline pressure required to achieve the current rated torque compared to the previous one A drum-type brake assembly that can be constructed has been constructed.

  This concept overcomes all of the above constraints in meeting the required friction level, pedal effort, cost, and packaging requirements while providing all the features of a drum brake, as described in the following sections.

  As novelty of the above-mentioned invention, information published in US and European patents can be obtained, and the citation list of the patent documents shown below includes the following patent specifications.

  The PCT / United States patent application filed on March 14, 1996 by Hino Motors Co., Ltd., with a patent number WO 96/07833, provides a brake key sound by providing a rod provided on the inner surface of the rim. The present invention relates to an invention that effectively reduces.

  The European patent application with patent number 95306755, filed September 25, 1995 by Ford Motor Company, relates to the invention of the mss damper which attenuates unpleasant noise.

  The European patent application with patent number 95306755, filed April 25, 1995 by Nisshinbo Co., Ltd. relates to the invention of a colored strip as a visual indicator of brake lining wear.

  PCT / USA patent application filed on May 30, 1996 by Tokyo Parts Industry Co., Ltd., generates a key sound by setting different natural frequencies for the two shoes. The present invention relates to an invention that reduces the possibility of doing so.

  The PCT / United States patent application, filed February 4, 2003 by TRW Motors, is related to an invention relating to an actuating device with a drive motor and electronics in the operation of a parking brake.

  The PCT / United States patent application filed March 3, 1987 by Ford Motor Company relates to the invention of a dual drum brake assembly that generates high brake torque.

  The United States Patent Application No. 4333211, filed June 1, 1982 by Toyota Motor Corporation, relates to the invention of a shoe hold down device in a drum brake.

  The PCT / United States patent application filed on November 26, 1992 by Automotive Products Plc is a regulator comprising a lever member and a pawl member, wherein the lever member Further, the present invention relates to an invention for preventing the temperature rise of the regulator by providing the pawl member together with a bimetallic strip on one brake shoe.

  A careful review of the cited literature and comparison with our invention reveals that it is clear that our invention is unique and different from the cited invention.

  Accordingly, the present invention proposes a drum brake assembly for an automobile as follows. That is, it has various purposes such as supplying a braking force larger than that normally possible, handling a higher speed, a larger size, a larger weight, etc. This drum type brake assembly aims to achieve the above-mentioned object without making an irregular change in size and weight.

  Further objects and advantages of the present invention will become apparent upon consideration of the drawings and the following description.

  The foregoing description is intended to be an overview, and other features of the invention will be better understood by those skilled in the art from the following detailed description of the invention. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should recognize that other structures can be easily designed or modified based on the disclosed concepts and specific embodiments to achieve the same objectives as the present invention. In the broadest embodiment, equivalent concepts should be recognized without departing from the features and scope of the invention.

[Summary of the Invention]
The inventors have spent a great deal of effort in providing a system that meets the needs of the industry and solves the problems associated with the prior art.

  In order to achieve the above object in accordance with the first aspect and features of the invention, a system is provided in an unused space on a leading shoe in the vicinity of a wheel cylinder to provide a drum brake for an automotive brake system. Used to increase the usefulness of the assembly.

  In addition to the first aspect and feature, in accordance with the second aspect and feature of the present invention, an additional lever is arranged and the brake output for a given pipeline pressure compared to the same drum brake structure. Space is utilized by connecting to existing line shoes so that the torque increases.

  Further objects of the invention will become clear from the following description.

  The accompanying drawings are intended to assist in understanding the invention, and are incorporated in and constitute a part of the invention. The above drawings illustrate embodiments of the invention and, together with the description, illustrate the principles of the invention. The above drawings are used as examples for explaining the nature of the present invention and are not intended to limit the present invention.

  For a complete understanding of the present invention, the following description is made with reference to the accompanying drawings.

The present invention will be described in detail with reference to the accompanying drawings shown below.
FIG. 1 is a front view of a conventional drum brake assembly.
FIG. 2 shows a front view of the proposed drum brake assembly. This diagram is provided as an example of the scope of the invention and is not intended to limit the invention.
FIG. 3 shows a schematic diagram of the action of forces acting in a conventional drum brake assembly.
FIG. 4 shows a schematic diagram of the action of forces acting on the high performance drum brake mechanism.
FIG. 5 shows a three-dimensional model of a high-performance drum brake assembly.
FIG. 6 shows a three-dimensional model of the back surface of the high performance drum brake assembly.
FIG. 7 shows a three-dimensional model in which a new lever arrangement in the line reading shoe assembly is enlarged.
FIG. 8 shows a three-dimensional model of the link used for Adams analysis.
FIG. 9 is a graph showing the input / output relationship of a conventional mechanism and the input / output relationship of a high-performance mechanism at an automobile speed of 25 km / h.
FIG. 10 is a graph showing the input / output relationship of a conventional mechanism and the input / output relationship of a high-performance mechanism at an automobile speed of 50 km / h.
FIG. 11 is a graph showing the input / output relationship of a conventional mechanism and the input / output relationship of a high-performance mechanism at an automobile speed of 50 km / h.

Detailed Description of the Invention
FIG. 1 represents a conventional drum brake in the United States.

  The drum type brake assembly consists of a rear plate (1), line leading shoe (2), line trailing shoe (3), wheel cylinder assembly (4), strut assembly (5), side brake lever (6), shoe hold. A down spring (7, 8) and a shoe return spring (9, 10) are provided.

  The wheel cylinder assembly (4) is fixed to the rear plate (1) with screws. The line leading shoe (2) and the line trailing shoe (3) are connected to the rear plate by a shoe hold down spring (7, 8) and a shoe return spring (9, 10). When the wheel cylinder assembly (4) is pushed in, the pistons (11, 12) in the wheel cylinder (4) push the line leading shoe (2) and the line trailing shoe (3), and the shoe return spring (9 , 10) The line leading shoe (2) and the line trailing shoe (3) are pushed against the rotation of the brake drum while withstanding the force of 10). In the line leading shoe (2) and the line trailing shoe (3), the wheel is decelerated by the resistance force generated against the brake drum. When the pressure is removed, the shoe return springs (9, 10) facilitate the pulling back of the line leading shoe (2) and the line trailing shoe (3) and return them to the normal (released) position. The wheel becomes free.

  FIG. 2 represents the high performance drum brake assembly of the present invention.

  Conventional drum brake assemblies are known to have a linear input / output relationship, and output amplification can be achieved by increasing the diameter of the wheel cylinder, increasing the friction level, It is known that attempts have been made by increasing the diameter itself. A prominent feature of the present invention is that a new lever is provided on the leading shoe web. Thereby, the output from the drum type brake assembly can be increased. It can be understood that the present invention uses the space on the web of the leading shoe located near the wheel cylinder. The leading shoe is connected to the line shoe in order to increase the output torque.

  In order to embody this idea of utilizing the space of a conventional drum brake assembly, structural improvements have been made to the leading shoe web. Details of the improvement will be described below.

  The configuration of the high performance drum brake assembly is shown in FIG. The newly added lever (17) has its one end supported by the wheel cylinder piston (11) and the other end supported by the strut (15). Rotate. This new lever (17) is in contact with the wheel cylinder piston (11) instead of the line leading shoe (19) and receives input from the depressed wheel cylinder assembly (4).

  The female push rod (20) of the strut assembly (15) is released at the entrance to accept the line leading shoe (19) and the width of the new lever (17) at the entrance.

  The new lever (17) has one end contacting the piston (11) of the wheel cylinder assembly (4) and the other end contacting the strut assembly (15). Rotate. This new lever (17) is in contact with the wheel cylinder assembly (4) piston (11) instead of the line leading shoe (19) and receives input from the pushed wheel cylinder assembly (4).

  When the wheel cylinder assembly (4) operates, the new lever (17) rotates about the rotation axis (18) and pushes the strut assembly (15). The line trailing shoe (3) now receives two inputs. That is, one is the force from the wheel cylinder assembly (4) and the other is the force from the strut assembly (15). Both are mechanically actuated by a new lever (17). The reaction force from the line trailing shoe (3) is transmitted as an input to the line leading shoe (19) via the straddled assembly (15). Both the input of the wheel cylinder assembly (4) and the reaction force of the strut assembly (15) act on the rotating shaft (18). As a result, almost twice the force acts on the leading shoe. The balance of the new lever (17) is achieved by the combined force of the force from the wheel cylinder assembly (4) and the reaction force from the strut assembly (15). This brake system needs to have a mechanism for automatic adjustment, and must be operated via a side brake mechanism or a service brake while the pressure is released.

  3 and 4 show the input from the wheel cylinder assembly (4) acting on the line leading shoe (19) and the line trailing shoe (3) in the conventional drum type brake assembly and the high performance drum type brake assembly. Represents pressure.

  FIGS. 5, 6, and 7 represent a three-dimensional model of a high performance drum brake assembly showing an assembly of several parts that make up the drum brake assembly of the present invention. FIG. 6 shows the assembly of the new lever in the brake assembly. FIG. 7 is an enlarged view of the arrangement of the levers in the line leading shoe assembly.

  To confirm the principle, a simple link model of the drum brake assembly was simulated using software, Adams / View 12.0, and the model is shown in FIG. The line leading shoe and the line trailing shoe are represented by a link (100) and a link (101), respectively. The strut (106) is positioned to pass the link while the link (100) and the link (101) are grounded. The new lever (102) is against the link (100) with one end in contact with the wheel cylinder input (104) and the other end in contact with the strut input end (105). And rotate (103). The above coupling structure is made by Adams / View 12.0, which is a kinematics simulation to understand the transfer mechanism.

  The new lever (102) is rotated relative to the link (100) by a revolute joint (108). Due to the transmission of force from the new lever (102) to the strut (106), the joint (109) of the parallel movement rotates.

  For simulation purposes, input pressure was applied to a new lever (102) and link (101) as shown. In simulation, the output pressure is received at the joint (108) along the axis of the strut (106).

  Compared to conventional drum brakes, the above Adams simulation can confirm our above considerations regarding the pressure amplification on the link (100) and link (101). The link (100) receives approximately twice the pressure at the joint (108) and the link (101) receives pressure through the shaft of the strut (106) in addition to the wheel cylinder input pressure (110). .

[Prominent features of high performance drum brake assembly]
1) The high-performance drum brake assembly for an automobile brake system further includes a lever located on the leading shoe web and contacting the wheel cylinder piston.

  2) Compared to the same mechanism, the above high performance drum brake assembly is designed to increase the brake torque for a given pipeline pressure or to achieve a rated brake torque mechanism. Needs to be substantially weakened.

  In order to verify the high-performance mechanism, a hydraulic automatic adjustment device having a diameter of 282 mm × 50.8 mm was developed for the purpose of trial production. The mechanism has a new feature that it is a brake that pulls forward. For testing to compare disparities in brake output torque, the conventional hydraulic self-adjusting device with a diameter of 282 mm × 50.8 mm, a forward pull drum brake assembly is also taken up. In the conventional mechanism and the high-performance mechanism, the wheel cylinder diameter, the position of the friction lining, the degree of friction lining, and the test inertia are the same for the dynamometer test.

  An inertia dynamometer test was conducted to compare the input / output relationship between the conventional mechanism and the high performance mechanism.

  The dynamometer test was carried out on different cars at the same speed and pressure. At each speed, the initial brake temperature is 80 ° C. and hydraulic pressure is applied to the brake assembly in increments of 10 bar from 20 bar to 80 bar. The input hydraulic pressure and the brake output torque at each speed and pressure are recorded and shown using a graph.

  9, 10 and 11 show the relationship between the input hydraulic pressure and the brake output torque at the speed of 50 km / h and the speed of 75 km / h in the same vehicle equipped with the conventional mechanism or the high performance mechanism. With respect to the conventional mechanism, the graph displaying the input pressure and the output brake torque is represented by a square legend. In the same test, the results obtained by the new mechanism are represented by a triangle legend. From the results of the test, it can be confirmed that the brake output torque in the high-performance mechanism has increased by about 60%. Reverse direction performance is also achieved, and an approximately 40% increase in brake output torque is observed. The increase in output is consistent with theoretical predictions, with marginal differences due to friction loss on the rotating shaft, drum distortion, friction material sensitivity to speed, pressure, and temperature.

  The increase in brake torque of the high performance mechanism under the test parameters is due to a newly developed concept, as explained in the detailed description of the preferred embodiment of the present invention.

  The output brake torque obtained by the high performance mechanism is substantially larger than that by the conventional brake.

  Generally, when a brake is applied to a heavy vehicle, the size (diameter) of the brake increases to obtain a higher brake torque. However, in the case of this newly developed drum brake assembly, it is possible to easily reduce the packaging while maintaining the outer dimensions.

  While the above description includes a number of limitations, these should not be construed as limitations on the scope of the invention, but are examples of preferred embodiments of the invention. The terms and expressions used herein are for the purpose of description and are not intended to limit the invention. This is because there is no intention of excluding equivalents having the features shown and described. It will also be appreciated that several different embodiments of the invention are possible without departing from the scope of the invention. For example, the “high performance drum brake” mechanism of the present invention can obtain a brake output torque at a lower pressure. Therefore, the thickness of the housing wall covering the wheel cylinder can be optimized. The mechanism can also be applied to an air-driven drum brake assembly that increases the brake output torque for a predetermined input air pressure.

  The present invention, which is a “high performance drum brake” mechanism, can output a brake torque substantially higher than that of a conventional drum brake assembly without having to increase the size of the drum brake and the size of the wheel. As a result, materials and costs can be saved and the device can be miniaturized.

  Accordingly, the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the illustrated embodiments.

[Advantages of the Invention]
1) The above high-performance mechanism can be applied to a conventional drum brake assembly, and can increase the brake torque for a predetermined pipeline pressure, or realize a rated brake torque mechanism with a substantially low pipeline pressure be able to.

  2) The high-performance mechanism can be applied to all existing types of drum brake assemblies.

  3) Compared to the equivalent mechanism, the high performance drum brake mechanism / assembly is smaller in terms of packaging.

  4) Compared to equivalent mechanisms, the high performance drum brake mechanisms / assemblies can output rated brake torque by using lower friction linings.

  5) Compared to the equivalent mechanism, the high performance drum brake mechanism / assembly can output the rated brake torque by using a smaller diameter wheel cylinder.

  6) Compared to an equivalent mechanism, the high performance drum brake assembly can increase the output obtained by the brake assembly by using a low friction lining. The brake assembly can easily cope with many problems such as maintenance of lining performance, grabbing, reduction of braking force, noise, and effectiveness of braking in the early morning.

It is a front view of the conventional drum type brake mechanism. It is a front view of the drum type brake mechanism of the present invention. It is the schematic of the force which acts in the conventional drum type brake mechanism. It is the schematic of the force which acts in a high performance drum type brake mechanism. It is a perspective view which shows the three-dimensional model of a high performance drum type brake mechanism. It is a perspective view which shows the three-dimensional model of the back surface of a high performance drum type brake assembly. It is a perspective view which shows the three-dimensional model which expanded and showed arrangement | positioning of the new lever on a line reading shoe. It is a perspective view showing the three-dimensional model of the link used for the Adams analysis. It is a graph showing the input / output relationship of a conventional mechanism and the input / output relationship of a high-performance mechanism at an automobile speed of 25 km / h. It is a graph showing the input / output relationship of a conventional mechanism and the input / output relationship of a high-performance mechanism at an automobile speed of 50 km / h. It is a graph showing the input / output relationship of a conventional mechanism and the input / output relationship of a high-performance mechanism at an automobile speed of 75 km / h.

Claims (12)

A high performance drum brake assembly for an automobile brake system,
The above drum brake assembly
A high-performance drum brake assembly characterized in that, by providing a member in an unused space on the leading shoe near the wheel cylinder, a higher brake output torque can be produced compared to a conventional drum brake mechanism.   The high-performance drum brake assembly according to claim 1, wherein the brake output torque is increased by arranging an additional lever connected to the existing line leading shoe in the unused space. The brake assembly includes a new lever that rotates with the web of the leading shoe,
One end of the lever is in contact with the wheel cylinder piston,
The other end is connected to the strut assembly,
2. The high performance drum brake assembly according to claim 1, wherein the lever is in contact with the piston instead of the line leading shoe web. Back plate,
With the above line reading shoe,
Line trailing shoes,
A shoe return spring,
Side brake lever,
With a shoe hold down spring,
2. A new lever can be provided to produce a larger output brake torque compared to the conventional drum brake assembly without increasing the diameter of the wheel cylinder and the diameter of the brake. High performance drum brake assembly as described in 1. The wheel cylinder is fixed to the rear plate with mounting screws,
The line shoe assembly is fixed to the rear plate by a shoe hold spring.
Line shoe assemblies are fixed to each other by shoe return springs,
2. The high-performance drum brake assembly according to claim 1, wherein the conventional drum brake is further provided with a lever that rotates on a web of the leading shoe. When the wheel cylinder assembly operates, the lever rotates around its axis of rotation, pushing the trailing shoe with the strut,
The trailing shoe receives two inputs, an input from the wheel cylinder assembly and an input from the strut assembly, and is mechanically operated by a new lever.
2. The high performance according to claim 1, wherein the force transmitted to the leading shoe is approximately doubled as a result of the input of the wheel cylinder and the reaction force of the strut acting on the rotating shaft. Drum brake assembly. By increasing the output obtained by the brake assembly, a low friction lining can be used,
The high-performance drum brake assembly according to claim 2, wherein the brake assembly can easily cope with many problems such as maintenance of lining performance, grabbing, reduction of braking force, and effectiveness of braking in the early morning. .   The output brake torque can be increased without increasing the diameter of the brake, so that the brake can be packaged to a usable wheel size. High performance drum brake assembly.   Incorporating the high performance drum brake assembly instead of the conventional brake saves raw materials, thus saving money, and provides the same output brake torque with the smaller diameter wheel cylinder The high-performance drum brake assembly according to any one of claims 1 to 4, wherein the high-performance drum brake assembly is provided.   6. The high-performance drum type according to claim 5, wherein the required hydraulic pressure can be reduced by incorporating the brake, and therefore, the required pedal acting force can be reduced and the regulation condition can be satisfied comfortably. Brake assembly.   The high-performance drum brake assembly according to claim 6, wherein the brake has an advantage that the output brake torque can be increased substantially linearly with respect to a predetermined hydraulic input pressure. .   A high performance drum brake assembly for an automotive brake system, fully described in the accompanying figures.

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