Patent Application
20080210486
1. Field of the Invention
The present application relates to an energy attenuation device for a liquid-conveying line, especially one that is adapted to convey a pressurized liquid therethrough.
Such a device is particularly suitable for placement in such a liquid-conveying line for the attenuation of pressure pulses in the liquid, especially in the hydraulic system of the power steering unit of a vehicle. However, the device of the present application would also be suitable for other hydraulic fluids.
2. Prior Art Statement
In hydraulic systems where the operating liquid is circulated by a pump, the pulsations of pressure that are generated by the pump are transmitted through the conduits and result in noise and/or vibration being produced by the hydraulic fluid. In the case of power steering fluid in vehicles, such noise and/or vibration is caused, for example, when vehicles are being parked or unparked at idle or very low speeds of movement of the vehicle, such as by barely moving into and out of a parking space or the like while the wheels of the vehicle are being turned by the power steering mechanism thereof. In particular, substantial noise and/or vibration (shudder) can be produced in such a situation when the power steering fluid passes through the power steering mechanism from the fluid pump to the effective steering structure. Further background in this area can be obtained from U.S. Pat. No. 3,323,305, Klees, whereby this U.S. patent is being incorporated into this disclosure by this reference thereto.
It is therefore an object of the present application to provide a new device for attenuating energy in a liquid-conveying line, in particular in a line that conveys fluid under pressure.
This object is realized by an energy attenuation device that comprises metal tubing disposed in the liquid-conveying line, a spring disposed in the metal tubing, and a spring-retaining means associated with the metal tubing to prevent or limit movement of the spring in the metal tubing in a downstream direction.
Other objects, uses and advantages of this invention are apparent from a reading of the specification in conjunction with the accompanying schematic drawings, which form a part thereof and wherein:
While the various features of this invention are hereinafter illustrated and described as providing a sound or energy attenuation device for an automotive power steering system, it is to be understood that the various features of this invention can be utilized singly or in various combinations thereof to provide an energy attenuation device for other systems that convey liquid, especially liquid under pressure. Therefore, this invention is not to be limited to only the embodiments illustrated in the drawings, because the drawings are merely utilized to illustrate one of the wide varieties of usages of this invention.
Referring now to the drawings in detail,
In order to greatly reduce noise, such as from resonance, for example in the pressure line 2 or in the return line 4, and thereby to eliminate or at least greatly reduce the power steering noise or vibration generated by the power steering pump 1 and/or by the power steering gear 3, the energy attenuation device of this application is disposed either in the return line 4, between the gear 3 and the reservoir 5 or the pump 1, or in the pressure line 2, between the steering pump 1 and the gear 3. In addition, it would also be conceivable to dispose the energy attenuation device of the present application in both the return line 4 and the pressure line 2.
Various exemplary embodiments of the energy attenuation device of the present application, which is indicated generally by the reference numeral 10, and components and arrangements thereof, are illustrated in the drawings and will be described in detail subsequently.
Although in the embodiment illustrated in
At any rate, the spring-retaining means 14 is merely intended to prevent or limit movement of the spring 12 in the tubing T in a downstream direction, but still allow flow of liquid through the tubing T.
It is to be understood that characteristics such as length, thickness, tension, number of coils per unit length, etc. of the spring 12 of the energy attenuation device 10 of the present application can vary in conformity with existing requirements. In addition, the spring 12 can be made of any suitable material, such as metal, especially stainless steel, or plastic. The tubing T, on the other hand, is made of metal, such as steel, aluminum, or a copper/nickel alloy. By way of example only, the tubing T can have an outer diameter of 0.95 cm (⅜ inch) or 1.27 cm (½ inch). Of course, the diameter can also be smaller or larger.
As indicated previously, the spring 12 could have a limited movement within the tubing T. In such a case, the outer diameter of the spring 12 would be at least slightly less than the inner diameter of the tubing T, as illustrated in
Although in the embodiments illustrated in
Although in the illustrated embodiments the springs 12 have been shown in straight sections of the tubing T, they could also be disposed in bent or curved sections of the tubing.
The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.
