Fluid-borne noise suppression in an automotive power steering system
AssigneeDana Corporation
InventorGail M. Cunningham
Life of this patent
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Abstract
A method of dampening fluid-borne noise in an automotive power steering system in accordance with a presently preferred embodiment of the invention contemplates provision of a power steering fluid hose having a laminated inner tube surrounded by a reinforcing outer tube. The inner tube has a resilient inner layer with a radial thickness T1 and a resilient outer layer with a radial thickness T2. The inner layer is softer than the outer layer and is bonded by vulcanization to the outer layer. The radial thicknesses T1 and T2 have a ratio selected to dampen fluid-borne noise within a preselected frequency range by elastic expansion of the inner and outer layers.
Claims7
A method of using a power steering fluid hose for dampening fluid-borne noise in automotive power steering system which comprises the steps of:
- (a) directing power steering fluid through a power steering fluid hose having a laminated inner tube surrounded by a reinforcing outer tube,
- (b) selecting the materials and radial thickness dimensions of said laminated inner tube to provide a resilient inner layer having good noise dampening properties with a radial thickness T1 and a resilient outer layer with a radial thickness T2 and having lesser noise dampening characteristics than said inner layer but capable of providing hoop strength reinforcement under adverse high temperature conditions,
- (c) selecting said inner layer material to have a softer durometer value than said outer layer
- (d) bonding said inner layer by vulcanization to said outer layer, and
- (e) selecting by empirical determination a ratio of said radial thicknesses T1 and T2 found to maximize dampening of fluid-borne noise in said system within a preselected frequency range by elastic radial expansion of said inner and outer layers.
A method of making a power steering pressure hose having a predetermined fluid-borne noise dampening characteristics, which comprises the steps of:
- (a) providing a laminated inner tube having an inner layer with a radial thickness T1 and an outer layer with a radial thickness T2, said inner layer having a hardness in the range of about 70 to 80 durometer, and said radial thickness T1 having a ratio to said outer thickness T2 in the range of about 30:70 to 70:30,
- (b) surrounding said inner tube with an outer reinforcing tube and
- (c) selecting by empirical determination a ratio of said radial thicknesses within said range to maximize dampening of fluid-borne noise by elastic radial expansion of said inner and outer layers.
Dependencies are inferred from the claim text.