구조해석을 이용한 차량용 브레이크 호스의 레이아웃 설계

Abstract

For modern people, automobiles are one of the most common means of transportation made for various technologies and purposes. Such a vehicle is composed of various parts such as an engine, a body, and an electric device, and operates in connection with each other for the purpose and safety of the driver. Among the various devices attached to the vehicle body, the brake system is the key device. A brake device is a device that slows down or stops a running vehicle by using frictional force, and maintains the parking state after stopping. It is the safety device that regulates the motion and potential energy of the vehicle. As the engine performance advances to increase the driving speed and the weight of the vehicle body, there are increasing number of researches on various brake systems for securing braking power. The hydraulic brake system is the common braking system that is well developed and commercially used. A brake system with a hydraulic device has a pipeline to transmit the pressure generated from the fluid. It is composed of a metal pipe and a rubber hose, which are connected depending on the purpose. In the case of a rubber hose, it is used when its elasticity and flexibility of rubber is required for the vehicle model. It is installed in the system by satisfying the specific length and radius of operation. The installed brake hose is a flexible pipeline that transmits hydraulic pressure and is defined by the peripheral device of the mounting unit, and the inside of the wheelhouse changes according to the operation of the steering wheel for vehicle rotation and braking. It should be satisfied that interference between brake hose and surrounding parts does not occur when the vehicle rotates or stops. In this study, I propose the new brake hose layout design process to solve the problems that arise when designing the layout of the brake hose. As an approach to reduce a lot of try and error and the design time, I study how to apply the results obtained from the tests to the analysis, and develop a program that automates this process so that it can be applied in the actual field. The material constant that is used in the analysis was obtained through uniaxial tensile, biaxial tensile, and pure shear tests for the rubber layer constituting the hose, and the equivalent material properties of the orthotropic material properties were obtained through the uniaxial tensile test and analysis for the partial investigation constituting the reinforcing layer. Layout analysis was performed using a program developed exclusively for layout analysis. To verify the result of the analysis, the actual deformation shape caused by twisting one end of the hose mounted in a U-shape and the layout according to the 9 phases of the brake hose implemented through a precision control robot were measured using 3D scanner. As a result of comparing the actual measurement result and the analysis result, it was confirmed that the shape of the layout obtained through the analysis well followed within maximum 10 mm difference with the actual measurement result, and when the maximum stress generated in the layout configuration and the maximum allowable stress of the material were compared, it is judged that there is no damage to the hose itself. And it was also confirmed that the role of braided layer is more greater than the rubber layer in the formation of the hose layout. Consequently, when comparing the existing layout design process with the new layout design process that have introduced structural analysis, the introduction of the new analysis step increases the progressive stages of the design process. However, the introduction of the analysis step can reduce the number of trial and error and the time of the review steps that are required for the brake hose layout design, and increase design robustness by analytically reviewing various forms of layout design for the brake hose in a limited design period.