Abstract:
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.

Description:
FIELD OF THE INVENTION 
     The present invention relates to mass dampers, and more particularly, to a mass damper for use in a hydraulic power steering system. 
     BACKGROUND OF THE INVENTION 
     In vehicle design, meeting noise and vibration requirements is increasingly important. In meeting both requirements, the design, placement, and operation of engine components in the engine compartment of a vehicle plays a significant role. 
     Generally speaking, components disposed in an engine compartment of a vehicle are subject to vibrational forces created by the engine and movement of a vehicle. For components such as hydraulic power steering hoses and the like, additional vibrational forces are created due to the pressure pulses and movement of hydraulic fluid within the system. Such additional vibrational forces can cause components to vibrate, rattle or squeak, thereby increasing passenger compartment noise and reducing occupant comfort. 
     In an effort to improve occupant comfort and reduce passenger and engine compartment noise, conventional damping systems have attempted to offset hydraulic noise through the use of tuning cables and restrictors. Tuning cables generally extend the length of a hydraulic hose and are specific to a particular hydraulic system. Specifically, conventional systems commonly include an elongate, wire wound cable, formed integrally with, or attached to, a hydraulic line and are operable to obviate the noise created by pressure pulses and/or moving fluid within the line. In essence, tuning cables serve to absorb the vibrational force created by the pressure pulses and moving hydraulic fluid and reduce the associated noise. While such systems effectively absorb vibrational forces created by pressure pulses and fluid movement, they fail to offset the additional vibrational forces caused by structural vibration. 
     Structural vibration is generally initiated by components disposed within an engine compartment of a vehicle. Such vibration generally transmits to a passenger compartment of the vehicle via systems that extend between the engine and passenger compartments. In one example, a hydraulic power steering system includes at least one hydraulic line which is attached at a first end to the engine compartment of a vehicle and at a second end at the hydraulic steering system. As previously discussed, an engine compartment of a vehicle experiences vibrational forces due to the movement of the vehicle and operation of the engine. In this regard, the first end of the hydraulic line, which is attached at the engine compartment, is subject to vibrational forces. As can be appreciated, the vibrational forces imparted on the first end of the hydraulic line tends to transfer from the attachment point to the line itself. Such structural vibration can cause the line to transmit vibration into the passenger compartment of the vehicle and create noise. 
     Therefore, a mass damper that is operable to absorb vibrational forces caused by both structural and fluid forces is desirable in the industry. Further, a mass damper that is capable of being tuned for different systems, thereby being easily transferable between different fluid lines and different systems, is desirable in the industry. 
     SUMMARY OF THE INVENTION 
     The present invention provides a power steering hose including a hose member having a first and second end and a damper disposed on the hose member. The damper is operable to attenuate noise or vibration between the first and second ends of the hose member and includes a cylindrical main body having a longitudinal axis and a bore formed in the main body. The bore is formed along the longitudinal axis of the main body and is operable to receive the hose member to fixedly attach the damper to the hose. The main body further includes a slot formed between an outer surface of the main body and the bore. The slot is operable to provide clearance for the hose member, thereby allowing the hose member to engage the bore. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a power steering hose and damper assembly in accordance with the principles of the present invention; 
         FIG. 2  is a perspective view of a damper in accordance with the principles of the present invention; 
         FIG. 3  is a plan view of the damper of  FIG. 2 ; 
         FIG. 4  is a perspective view of a second embodiment of a damper in accordance with the principles of the present invention; 
         FIG. 5  is a plan view of the damper of  FIG. 4 ; 
         FIG. 6  is a perspective view of a third embodiment of a damper in a accordance with the principles of the present invention; and 
         FIG. 7  is a plan view of the damper of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     With reference to the figures, a mass damper  10  is provided for use in attenuating and reducing vibrational noise. Mass damper  10  comprises a main body  12  having a longitudinal axis  14 , a bore  16  formed along the longitudinal axis  14 , and a slot  18  formed in the main body  12 . 
     With particular reference to  FIGS. 2 and 3 , the main body  12  is shown to include a generally cylindrical shape having a first end  20 , a second end  22 , an outer surface  24 , an inner surface  26 , and a planar surface  28 . The first and second ends  20 ,  22  are formed on opposite ends of the main body  12  and generally define an overall length of the main body  12 . The longitudinal axis  14  extends in a direction between the first and second ends  20 ,  22  and is formed generally at the midpoint of both the main body  12  and bore  16 . While a cylindrical shape is disclosed, it should be understood that the main body  12  could comprise any suitable shape, such as, but not limited to, square or rectangular, and should be considered within the scope of the invention. While the main body  12  is described as having a generally cylindrical shape, it should be understood that the shape and overall mass of the main body  12  is dictated by the particular application and system in which the mass damper  10  is used. 
     The outer surface  24  and inner surface  26  each extend between the first and second ends  20 ,  22  of the main body  12 , as best shown in  FIG. 2 . The outer surface  24  includes a generally arcuate surface  30  forming an outer diameter of the main body  12  while the inner surface  26  similarly comprises an arcuate surface  32  and forms an inner diameter of the main body  12 . 
     The bore  16  is formed through the main body  12  and extends between the first and second ends  20 ,  22  along the longitudinal axis  14  such that a first circular opening  34  is formed on the first end  20  and a second circular opening  36  is formed on the second end  22 . As can be appreciated, the circular openings  34 ,  36  define the overall diameter of the bore  16  and are generally formed coaxially with the longitudinal axis  14 . In this manner, the bore  16  serves to define the inner limit of a thick-walled cylinder body wall  38 , a thickness of which is generally defined between the outer surface  24  and inner surface  26  of the main body  12 . 
     With particular reference to  FIG. 2 , the planar surface  28  is shown to include a first surface  40  and a second surface  42 . The first and second surfaces  40 ,  42  are formed in the outer surface  24  of the main body  12  and are formed such that the first surface  40  is generally co-planar with the second surface  42 . 
     The slot  18  is formed in the main body  12  generally along the longitudinal axis  14  and extends between the first and second ends  20 ,  22 . The slot  18  is formed through the wall  38  of the main body  12  and is disposed generally between the first and second surfaces  40 ,  42  of the planar surface  28 . The slot  18  extends from the first and second surfaces  40 ,  42  and terminates at the inner surface  26  such that an opening  44  to the bore  16  is formed in the main body  12  having a pair of chamfered surfaces  45 ,  47 . The formation of the slot  18  creates a first and second walled surface  46 ,  48  formed in the wall  38  of the housing  12 , whereby the first and second walled surface  46 ,  48  are formed generally perpendicular to the first and second surfaces  40 ,  42  of the planar surface  28 . As best shown in  FIG. 3 , the width of the slot  18 , as measured from the first walled surface  46  to the second walled surface  48 , is generally smaller than the diameter of the bore  16 . While the slot  18  is described as having a width generally smaller than the diameter of the bore  16 , it should be understood that the slot  18  could be of an equivalent diameter to that of the bore  16 , and should be considered as part of the present invention. 
     With particular reference to  FIGS. 4 and 5 , a second embodiment of the mass damper  10   a  is shown having a main body  12   a , a longitudinal axis  14 , a bore  16 , and a slot  18   a . In view of the substantial similarity in structure and function of the components associated with the mass damper  10  of  FIGS. 1–3  with respect to the mass damper  10   a , like reference numerals are used hereinafter and in the drawings to identify like components while like reference numerals containing letter extensions are used to identify those components that have been modified. 
     The main body  12   a  comprises a generally cylindrical shape and includes a bore  16 , an outer surface  24   a , and an inner surface  26 . The bore  16  extends along the longitudinal axis  14  and extends between a first and second end  20 ,  22  of the main body  12   a.    
     The slot  18   a  is formed in the main body  12   a  along the longitudinal axis  14  and extends generally between the outer surface  24   a  and inner surface  26 . In this regard, the slot  18   a  is operable to create an opening  44   a  to the bore  16 . As can be appreciated, the opening  44   a  creates a first and second walled surface  46   a ,  48   a  formed in a wall  38   a  of the main body  12   a . The first and second walled surfaces  46   a ,  48   a  are formed parallel to the longitudinal axis  14  of the main body  12   a  and extend from the outer surface  24   a  to the inner surface  26 . In this regard, the width of the slot  18   a  is generally smaller than a diameter of the bore  16 , whereby the width is measured between the first walled surface  46   a  and the second walled surface  48   a . While the slot  18   a  is described as having a width generally smaller than the diameter of the bore  16 , it should be understood that the slot  18   a  could be of an equivalent diameter to that of the bore  16 , and should be considered as part of the present invention. 
     With particular reference to  FIGS. 6 and 7 , a third embodiment of the mass damper  10   b  is shown having a main body  12   b , a longitudinal axis  14 , and a bore  16 . In view of the substantial similarity in structure and function of the components associated with the mass damper  10  with respect to the mass damper  10   b , like reference numerals are used hereinafter and in the drawings to identify like components while like reference numerals containing letter extensions are used to identify those components that have been modified. 
     The main body  12   b  of the mass damper  10   b  includes an outer surface  24   b  and an inner surface  26   b , whereby the wall  38   b  of the main body  12   b  is defined therebetween. The bore  16  extends the length of the main body  12   b  and is formed along the longitudinal axis  14  such that the main body  12   b  forms a closed thick-walled body, here a cylinder, as shown in  FIGS. 6–7 . 
     With particular reference to  FIGS. 1–2 , the operation of the mass damper  10  will be described in detail. In view of the substantial similarity and function between the mass damper  10  with the mass damper  10   a , a detailed description of the mass damper  10   a  is foregone. 
     The mass damper  10  is operable to absorb a vibrational force exerted on a flexible member, such as a power steering hose  50 . The power steering hose  50  includes an elongate tubular member  52  formed from a suitable flexible material such as rubber or the like and having a flexible outer wall  58  and a bore  60  extending along its length. The overall length of the hose  50  is defined between first and second ends  54 ,  56 . 
     Each of the first and second ends  54 ,  56  includes a first and second fastening element  62 ,  64  for attachment to a fluid system such as a power steering system (not shown). Each fastening element  62 ,  64  includes a central opening  66 ,  68  that is continuous with bore  60  to fluidly and sealingly connect bore  60  with the fluid system. 
     The mass damper  10  is attached to the tubular member  52  of the power steering hose  50  at a predetermined location to prevent noise caused by vibrational forces exerted on the hose  50 . The location of the mass damper  10  along the tubular member  52  is specific to each application and is dependent on the type of hose  50  (diameter, material characteristics, wall thickness), length of the hose  50 , and the forces exerted thereon (magnitude, direction, frequency, internal vs. external). 
     The mass dampers  10 ,  10   a  are attached to the hose  50  generally at the bore  16  of the main body  12 . Specifically, a length of the tubular member  52  is compressed such that the tubular member  52  of the hose  50  can pass though the generally smaller opening  44  of the slot  18 . Specifically, a compressive force is applied to the flexible outer wall  58  such that its profile generally assumes a slightly smaller width than that of the slot  18 . Once the hose  50  is sufficiently compressed, the hose  50  is inserted through the slot  18  and into the bore  16  of the main body  12 . 
     Once the tubular member  52  of the hose  50  is disposed within the bore  16 , the compressive force exerted on the hose  50  is released, thereby allowing the hose  50  to once again assume its tubular or cylindrical shape. As can be appreciated, the hose  50  will naturally assume its original cylindrical shape once the compressive force exerted on the flexible outer wall  58  is released due to the nature of the flexible material of the hose  50 . 
     Mass damper  10   b , lacking the gap  18  found in mass dampers  10 ,  10   a , clearly cannot be installed on the tubular member  52  in the same manner as dampers  10 ,  10   a . Mass damper  10   b , therefore, is generally of a two-piece construction, such as two semi-cylindrical sections (not shown) that are joined around tubular member  52  so that tubular member  52  occupies bore  16 . The two semi-cylinder sections are then secured to each other such as by pins, bolts, bands or snaps, to form a solid thick-walled cylinder closely surrounding tubular member  52 . 
     In an alternative manner of installing the damper  10   b  on the hose  50 , one of the first or second ends  62 ,  64  of the hose  50  is inserted into the bore  16  of the main body  12   b  and mass damper  10   b  is moved long the length of the hose  50  until it is properly positioned thereon. As can be appreciated, the flexible outer wall  58  is operable to engage the bore  16  of the main body  12   b  and hold the mass damper  10   b  in a position along the length of the hose  50 . 
     The hose  50  includes an outer diameter, which is generally larger than the inner diameter of the bore  16 . In this regard, the mass damper  10  is effectively held in a predetermined position on the hose  50  between the first and second ends  54 ,  56  due to a force exerted by the flexible wall  58  on the inner surface  26  of the bore  16 . As previously discussed, the specific location of the mass damper  10  along the tubular member  52  of the hose  50  is determined by the material of the hose  50 , length of the hose  50 , and forces exerted on the system. 
     In any of the foregoing embodiments, the relative position of the mass damper  10 ,  10   a ,  10   b  along a length of the hose  50  is governed by first determining the vibrational forces exerted on the hose  50  and is positioned such that the damper effectively reduces vibrational noise. Vibrational noise is created when the hose  50  experiences external vibrational forces. External vibrational forces are imparted on the system generally at the first and/or second fastening elements  62 ,  64  as well as forces applied directly to the hose  50 . The mass damper  10  is operable to absorb such vibrational forces to prevent vibrational noise caused by slight movement of the hose  50 . As previously discussed, the exact location of the mass damper  10  along the hose  50  between the first and second ends  54 ,  56  is generally a function of the flexible material used in the formation of the tubular member  52  and the overall length of the hose  50 . 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.