Power Steering Hose Research Articles

Numerical investigation of swaging process characteristics of fabric braided power steering hose

The power steering hose in automotive power steering system is composed of a rubber hose and two metal fittings. The rubber hose is reinforced by fabric braided layers, while metal fittings are firmly clamped to both ends of rubber hose by the special swaging job. Since the main function of power steering hose is to circulate internal oil without oil leakage, the swaging process of metal fitting should be elaborately designed based on the profound investigation of process characteristics. However, owing to the complex micro structure of braided layers, the swaging process has been investigated either by time- and cost-consuming experiment or by the simple numerical analysis in which the braided layers are simplified as an isotropic solid. To overcome the demerit of experiment and to improve the accuracy of numerical method, an effective numerical analysis method by considering the anisotropy of braided layer is presented in this paper. The braided layers are modeled as an orthotropic solid and their equivalent material properties are derived by utilizing the homogenization method. Through the numerical experiments, the difference between the simple isotropic model and the current orthotropic one is compared, and the swaging process characteristics are investigated to the helix angle.

Effect of Dimensions of Crimped Portion upon Sealing Performance of Hydraulic Brake Hose by Applying Three-Dimensional FEM Analysis

Usually, development of automobile brake hose and power steering hose has been realized through investigating several actual prototype hoses experimentally. Recently, high durability for brake hose has been required because periodic renewing the brake hoses has not been requested anymore. In this study, three-dimensional FEM analysis has been applied to the crimped portion of hydraulic brake hose in order to investigate the effects of manufacturing errors upon the sealing performance. In order to evaluate the sealing performance, the normal stress σr appearing between the inner rubber and nipple is mainly considered. Then, the sealing performance is investigated when the manufacturing error is included for the crimped portion of hydraulic brake hose. It is found that maximum stress between the nipple and inner rubber decreases by less than 30% when the manufacturing errors are smaller than the upper limit of tolerance. It may be concluded that the error may causes deterioration of sealing performance of hydraulic brake hose.

New metal fitting geometry and optimization of the swaging parameters for an automobile power steering hose

To solve the power steering (PS) hose oil leakage problem in automobile applications, a new geometry design of the metal fitting is required, and the swaging conditions applied to the PS hose should be optimized. In this study, a new metal fitting geometry for the PS hose was proposed. A CAE simulation for both the proposed and the conventional metal fittings was conducted, and both the stress and the strain in the PS hose were compared. An experimental verification was also performed with these two different metal fittings. Additionally, the swaging conditions were optimized by the durability cycle time, which was measured in an impulse test of the swaged PS hose. For a more economical production, practical working conditions were also recommended and experimentally verified.

Effect of Dimensions of Crimped Portion upon Sealing Performance of Hydraulic Brake Hose by Applying Three-Dimensional FEM Analysis

Usually, development of automobile brake hose and power steering hose has been realized through investigating several actual prototype hoses experimentally. Recently, high durability for brake hose has been required because periodic renewing the brake hoses has not been requested anymore. In this study, three-dimensional FEM analysis has been applied to the crimped portion of hydraulic brake hose in order to investigate the effects of manufacturing errors upon the sealing performance. In order to evaluate the sealing performance, the normal stress σr appearing between the inner rubber and nipple is mainly considered. Then, the sealing performance is investigated when the manufacturing error is included for the crimped portion of hydraulic brake hose. It is found that maximum stress between the nipple and inner rubber decreases by less than 30% when the manufacturing errors are smaller than the upper limit of tolerance. It may be concluded that the error may causes deterioration of sealing performance of hydraulic brake hose.

It is not always the seal

According to media reports, Honda is recalling some models of its Acura in the USA and Asia because of a defect in the O-ring gasket and power-steering hose.

FEM Analysis for Sealing Performance of Hydraulic Pressure Brake Hose Caulking Portion

Usually, development of automobile brake hose and power steering hose has been realized through evaluating several actual prototype hoses experimentally. Recently, high durability and high development effect for brake hose has been required because periodic exchange for the brake hose has not been requested any more. In this study, therefore, stress analysis by FEM is performed to the crimped portion of hydraulic pressure brake hose in order to promote the development of the automobile hoses more efficiently. It is found that large normal stresses σr in the radial direction appear at the crimped portion between the nipple and inner rubber. The results suggest that several grooves on the nipple surface may be useful because they cause large σr, which may improve the sealing performance. The effect of permanent deformation of the rubber on the sealing performance is discussed by assuming initial deformation of the rubber at the crimped portion.

FEM Analysis for Sealing Performance of Hydraulic Brake Hose Crimped Portion and Its Life Estimation

Usually, development of automobile brake hose and power steering hose has been realized through investigating several actual prototype hoses experimentally. Recently, high durability for brake hose has been required because periodic renewing the brake hoses has not been requested anymore. In this study, FEM stress analysis has been applied to the crimped portion of hydraulic brake hose in order to promote the development of the automobile hoses more efficiently. It is found that large normal stresses σn, which may be helpful for the sealing performance, appear at the crimped portion between the nipple and inner rubber. The results suggest that several grooves putting at the surface of nipple are effective for causing large σn, which may improve the sealing performance and hose life. The effect of compression set of the rubber on the sealing performance is investigated, and the life of hydraulic brake hose is estimated form the maximum stress appearing near the groove on the nipple.

Mechanical Behaviors of a Power Steering Hose Assembly during the Swaging Process

In this study, finite element analyses for the mechanical behaviors of a power steering hose assembly during the swaging process were performed in order to investigate the stress level of hose components according to jaw strokes, and to examine the effect of friction coefficient on the contact force. The physical properties such as Mooney-Rivlin constants of rubber materials and the work-hardening data of the steel were obtained through the experiments, and the contact conditions identical to the swaging process were taken into account. Two reinforced layers included in the hose were modeled with axisymmetric rebar elements in the general-purpose program, MSC MARC2000. The updated Lagrange formulation and the large displacement option were employed in the analysis. The result interpretations were focused on the rubber components which are in contact with the metal components, because of their important roles in the hose efficiency.

Swaging process of power steering hose: Its finite element analysis considering the stress relaxation

Abstract Rubber layers in the power steering hose display the stress relaxation after the swaging forming load is released. This paper presents the nonlinear finite element analysis of the swaging process of the power steering hose by considering the stress relaxation in terms of a Prony series expansion. Numerical results illustrating the theoretical work confirm that the stress relaxation of rubber layers cannot be ignored for the reliable numerical simulation of the swaging process.

Prediction of Effective Mechanical Properties of Reinforced Braid by 3-D Finite Element Analysis

The numerical prediction of the effective mechanical properties of the reinforced braid inserted in automobile power steering hose is addressed. The key role of the reinforced braid layer is to suppress the excessive radial expansion of the hose subject to high pressure and temperature. The reinforced braid layer is in the structure composed of wrap and fill tows inclined to each with the specific helix angle. In order to predict the effective mechanical properties, we construct a 3-D finite element model of the unit cell (or RVE) of the reinforced braid in a periodic pattern, in which the detailed geometry of individual fiber tows is fully modeled. By making use of the superposition method and the 3-D finite element analysis, the effective mechanical properties are predicted. Numerical experiments illustrating the theoretical work are also presented.

Power steering noise and vibration attenuator

A noise and vibration attenuator for a power steering hose is disposed on the flexible tubular portion of the hose. The damper is operable to attenuate noise or vibration found in the hose and includes a cylindrical main body having a central bore on the longitudinal axis of the main body. The bore is operable to receive the flexible tubular portion of the hose and fix the position of the damper on the hose. The main body can include a slot formed through the main body to the bore, operable to provide clearance for the hose member to be inserted from the side of the cylinder into the bore. The main body can also be solid, requiring that the hose be inserted into the bore in a longitudinal direction.

Nonlinear finite element analysis of swaging process for automobile power steering hose

The power steering system of automobile is activated by high pressure filled within the power steering hose that is connected between the oil pump and the steering gear box with the metal fittings. The main function of the steering hose is to circulate oil without any oil leakage, for which both the hose and the metal fitting are swaged firmly. The swaging job of the steering hose with the metal fittings is performed with two sets of dies composed of specific jaws, and this job leads to the large deformation of both the rubber hose and the metal fitting. Thus, this swaging process is characterized by geometry, material and boundary nonlinearities. In this context, the current study intends to investigate the swaging process characteristics through the nonlinear finite element analysis.

상세 유한요소 모델을 이용한 섬유 보강사의 등가물성 유도

Reinforced braid layer (RBL) in automobile power steering hose plays an important role in power steering system. When the working oil is applied to the power steering hose, RBL suppresses rubber hose deformation from internal pressure and heat expansion. RBL is woven textile composites having a double-row structure of nylon cords twisted with the specific helix angle. In this paper. effective material properties of RBL are estimated using a detailed 3-D finite element model considering its complicated geometry. Numerical experiments based on a superposition method are carried out to simulate uniaxial tensile loading condition.<br/>

자동차용 파워스티어링 호스의 스웨이징 공정 유한요소해석

The nonlinear finite element analysis for deformation characteristics of a power steering hose during the swaging process is performed in order to investigate the stress and the strain levels of the hose components. Power steering hose consists of components such as rubber hose, nylon, nipple and sleeve. Moreover, the numerical analysis requires the consideration of material, geometry and boundary nonlinearities. To evaluate the rubber hose strength, the measured stresses and strains are compared with tension and compression test data. Contact force is also a principal factor to examine whether rubber hose is break away from sleeve and nipple or not.br/

내압을 받는 파워스티어링 호스의 유한요소해석

The objective of this paper is to numerically examine the mechanical behavior of the swaged power steering(PS) hose subject to internal pressure. PS hose experiences a large internal pressure change in operating, so it`s material part has to resist a cyclic expansion and compression without causing oil leakage. This cyclic pressure is intimately associated with fatigue failure of PS hose. In this study, we compare two types of PS hose. The numerical investigation is composed of three steps; swaging analysis, low and high pressure analyses. The comparative numerical results provide the basic data for the optimal PS design.

Hydrogenated NBR (HNBR) in Power Steering Hose

This paper considers the relative performance of HNBR, NBR, CSM and CM Elastomers in a power steering environment. Also discussed are the effects of oxidised fluids and additive packages on the elastomer compound. The paper highlights recent changes in requirements for hoses in power steering applications and describes how HNBR can help hose manufacturers meet these requirements.

Hydrogenated NBR (HNBR) in Power Steering Hose

This paper considers the relative performance of HNBR, NBR, CSM and CM Elastomers in a power steering environment. Also discussed are the effects of oxidised fluids and additive packages on the elastomer compound. The paper highlights recent changes in requirements for hoses in power steering applications and describes how HNBR can help hose manufacturers meet these requirements.