WO2021092040A1 - Steering damper assembly - Google Patents

Steering damper assembly Download PDF

Info

Publication number
WO2021092040A1
WO2021092040A1 PCT/US2020/058923 US2020058923W WO2021092040A1 WO 2021092040 A1 WO2021092040 A1 WO 2021092040A1 US 2020058923 W US2020058923 W US 2020058923W WO 2021092040 A1 WO2021092040 A1 WO 2021092040A1
Authority
WO
WIPO (PCT)
Prior art keywords
endcap
steering damper
damper assembly
axis
working chamber
Prior art date
Application number
PCT/US2020/058923
Other languages
French (fr)
Inventor
Daniel Keil
Darrell Breese
Ben Schaller
Original Assignee
DRiV Automotive Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US16/674,608 external-priority patent/US20210131523A1/en
Application filed by DRiV Automotive Inc. filed Critical DRiV Automotive Inc.
Publication of WO2021092040A1 publication Critical patent/WO2021092040A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D7/00—Steering linkage; Stub axles or their mountings
    • B62D7/22—Arrangements for reducing or eliminating reaction, e.g. vibration, from parts, e.g. wheels, of the steering system
    • B62D7/228—Arrangements for reducing or eliminating reaction, e.g. vibration, from parts, e.g. wheels, of the steering system acting between the steering gear and the road wheels, e.g. on tie-rod
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/06—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using both gas and liquid
    • F16F9/064—Units characterised by the location or shape of the expansion chamber
    • F16F9/065—Expansion chamber provided on the upper or lower end of a damper, separately there from or laterally on the damper
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/10—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using liquid only; using a fluid of which the nature is immaterial
    • F16F9/14—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect
    • F16F9/16—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts
    • F16F9/18—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts with a closed cylinder and a piston separating two or more working spaces therein
    • F16F9/185—Bitubular units
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/3207—Constructional features
    • F16F9/3235—Constructional features of cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/3207—Constructional features
    • F16F9/3235—Constructional features of cylinders
    • F16F9/3242—Constructional features of cylinders of cylinder ends, e.g. caps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/36—Special sealings, including sealings or guides for piston-rods
    • F16F9/362—Combination of sealing and guide arrangements for piston rods
    • F16F9/364—Combination of sealing and guide arrangements for piston rods of multi-tube dampers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F2224/00—Materials; Material properties
    • F16F2224/02—Materials; Material properties solids
    • F16F2224/0225—Cellular, e.g. microcellular foam
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F2230/00—Purpose; Design features
    • F16F2230/20—Location of equilibration chamber

Definitions

  • Vehicles typically include steering systems. During operation of a vehicle, the steering system can be subject to vibrations and shocks from the driving surface. Some steering systems include a steering damper or steering stabilizer to absorb or dampen the vibrations and shocks from the driving surface.
  • Figure l is a perspective view of an example steering damper assembly.
  • Figure 2 is a side cross-sectional view of the steering damper assembly with a piston in an extended position.
  • Figure 3 is a side cross-sectional view of the steering damper assembly with the piston in a retracted position.
  • Figure 4 is a front cross-sectional view of the steering damper.
  • Figure 5 is a front cross-sectional view of another example of the steering damper.
  • Figure 6 is rear plan view of a first endcap of the steering damper.
  • Figure 7 is a side view of the first endcap.
  • Figure 8 is a front plan view of the first endcap.
  • Figure 9 is side cross-sectional view of the first endcap along line 9-9 in Figure 6.
  • Figure 10 is a cross-sectional view of a portion of the first endcap along line 10-10 in Figure 6.
  • Figure 11 is a side cross-sectional view of the first endcap along line 11-11 in Figure 7.
  • Figure 12 is a cross-sectional view of a portion of the first endcap along line 12-12 in Figure 3.
  • Figure 13 is a cross-sectional view of a portion of the first endcap along line 13-13 in Figure 3.
  • Figure 14 is a perspective view of a portion of the first endcap.
  • Figure 15 is a side cross-sectional view of a portion of the steering damper assembly with a basecap.
  • Figure 16 is a plan view of the basecap.
  • Figure 17 is a perspective view of the basecap.
  • a steering damper assembly 30 includes a cylindrical pressure tube 32 including a first endcap 34, a second endcap 36, and a tubular wall 40 defining and extending along an axis A from the first endcap 34 to the second endcap 36, the pressure tube 32 defining a working chamber 42; a piston assembly 44 disposed in the working chamber 42 and dividing the working chamber 42 into a first working chamber 46 adjacent the first endcap 34 and a second working chamber 48 adjacent the second endcap 36; a reserve tube 50 extending circumferentially around the pressure tube 32 and defining a reservoir chamber 52 that is radially between the reserve tube 50 and the pressure tube 32; a base valve 54 fluidly connecting and controlling flow between the second working chamber 48 and the reservoir chamber 52; and a piston rod 56 fixed to the piston assembly 44 and extending through the first endcap 34 of the pressure tube 32.
  • the reserve tube 50 includes a cylindrical portion 58 and a bulged portion 60.
  • the cylindrical portion 58 extends from the first endcap 34 of the pressure tube 32 toward the second endcap 36 of the pressure tube 32 and extends concentrically around the pressure tube 32, the cylindrical portion 58 having an inner radius R yi from the axis A.
  • the bulged portion 60 includes a first circumferential section 62 and a second circumferential section 64, the first circumferential section 62 having a maximum radial distance Lbuii from the axis A at most equal to the inner radius R cyi of the cylindrical portion 58, and the second circumferential section 64 having a maximum radial distance Lbui 2 from the axis A greater than the inner radius R cyi of the cylindrical portion 58.
  • the steering damper assembly 30 provides a way to mitigate negative effects of air introduced into the reservoir chamber 52.
  • the bulged portion 60 of the reserve tube 50 provides a location for air in the reservoir chamber 52 to go, which can prevent the air from traveling into the working chamber 42. Air in the working chamber 42 can cause lagging in the absorption or dampening of shocks and vibrations.
  • the shape of the reserve tube 50 with the cylindrical portion 58 and the bulged portion 60 provides an easy-to-manufacture design using a small number of parts and a small amount of material.
  • the steering damper assembly 30 has a compact shape, which helps packaging in a steering system of a vehicle.
  • the steering damper assembly 30 is mountable to the steering system of the vehicle (not shown).
  • the steering damper assembly 30 includes a first mount 66 and a second mount 68.
  • the mounts 66, 68 are each attachable to a point on the vehicle.
  • one of the mounts 66, 68 can be attached to a point that is fixed relative to a body of the vehicle, and the other of the mounts 66, 68 can be attached to a point that moves with components of the steering system relative to the body of the vehicle.
  • the steering damper assembly 30 is oriented generally horizontally, specifically, such that the axis A is oriented generally horizontally.
  • the steering damper assembly 30, also referred to as a steering stabilizer can absorb vibrations and shocks transmitted through the steering system.
  • the pressure tube 32 has a cylindrical shape defining the axis A.
  • the pressure tube 32 includes the first endcap 34, the second endcap 36, and the tubular wall 40.
  • the first endcap 34 and the second endcap 36 each have a circular shape centered on the axis A.
  • the tubular wall 40 has a circular cross-section orthogonal to the axis A, and the circular cross-section is projected from the first endcap 34 to the second endcap 36.
  • the first endcap 34 and the second endcap 36 extend radially inward from the tubular wall 40 toward the axis A.
  • the first endcap 34, the second endcap 36, and the tubular wall 40 are attached to and fixed relative to each other.
  • the pressure tube 32 defines the working chamber 42.
  • the working chamber 42 is contained within the pressure tube 32.
  • the working chamber 42 is sealed such that fluid can only flow into or out of the working chamber 42 through the base valve 54.
  • the piston assembly 44 is disposed in the working chamber 42.
  • the piston assembly 44 has a circular cross-section centered on the axis A and forming a seal with the tubular wall 40.
  • the piston assembly 44 contacts and forms a seal with the tubular wall 40 circumferentially for 360° around the axis A.
  • the piston assembly 44 divides the working chamber 42 into the first working chamber 46 and the second working chamber 48.
  • the first working chamber 46 is adjacent the first endcap 34 and is enclosed by the first endcap 34, the tubular wall 40, and the piston assembly 44.
  • the second working chamber 48 is adjacent the second endcap 36 and is enclosed by the second endcap 36, the tubular wall 40, and the piston assembly 44.
  • the piston assembly 44 includes a piston valve 70.
  • the piston valve 70 permits flow between the first working chamber 46 and the second working chamber 48, i.e., through the piston assembly 44, as the piston assembly 44 moves axially, i.e., translates along the axis A.
  • the piston valve 70 permits flow of fluid out of the second working chamber 48 into the first working chamber 46 to compensate for the relative change in volume between the first working chamber 46 and the second working chamber 48, and as the piston assembly 44 and piston rod 56 move axially toward the first endcap 34, the base valve 54 permits flow of fluid into the second working chamber 48 from the first working chamber 46 to compensate for the relative change in volume between the first working chamber 46 and the second working chamber 48.
  • the piston valve 70 can be sized to permit a defined rate of flow between the first working chamber 46 and the second working chamber 48.
  • the piston rod 56 is fixed to the piston assembly 44.
  • the piston rod 56 extends from the piston assembly 44 to and through the first endcap 34 of the pressure tube 32.
  • the piston rod 56 is disposed partially inside the first working chamber 46 and partially outside the pressure tube 32.
  • the piston rod 56 has a constant cross-section that is projected from the piston assembly 44 through the first endcap 34 to the first mount 66.
  • the piston assembly 44, the piston rod 56, and the first mount 66 are attached to and fixed relative to each other.
  • the first endcap 34 includes a first-endcap seal 72 extending circumferentially around the piston rod 56 and forming a seal with the piston rod 56.
  • the first-endcap seal 72 prevents fluid in the first working chamber 46 from leaking out of the pressure tube 32 along the piston rod 56.
  • the base valve 54 fluidly connects and controls flow between the second working chamber 48 and the reservoir chamber 52.
  • the base valve 54 extends through the second endcap 36.
  • the base valve 54 permits flow of fluid out of the second working chamber 48 into the reservoir chamber 52 to compensate for the additional volume in the working chamber 42 occupied by the piston rod 56, and as the piston assembly 44 and piston rod 56 move axially toward the first endcap 34, the base valve 54 permits flow of fluid into the second working chamber 48 from the reservoir chamber 52 to compensate for the reduction in volume in the working chamber 42 occupied by the piston rod 56.
  • the base valve 54 can be sized to permit a defined rate of flow between the second working chamber 48 and the reservoir chamber 52.
  • the first mount 66 provides a location to attach the steering damper assembly 30 to a steering system.
  • the first mount 66 can permit rotation in one or more dimensions of the steering damper assembly 30 relative to the component of the steering system to which the first mount 66 is attached.
  • the first mount 66 can be a pin joint, ball joint, etc.
  • the first mount 66, the piston rod 56, the piston assembly 44, and a dust shield 74 together form a rigid body, i.e., are connected to each other and fixed relative to each other.
  • the first mount 66, the piston rod 56, the piston assembly 44, and the dust shield 74 are axially movable together relative to the pressure tube 32 between a retracted position with the piston assembly 44 at a closest position to the second endcap 36, as shown in Figure 3, and an extended position with the piston assembly 44 at a farthest position from the second endcap 36, as shown in Figure 2.
  • the rigid body axially moves from the extended position to the retracted position, fluid moves from the second working chamber 48 to the first working chamber 46 through the piston valve 70, and fluid moves from the second working chamber 48 to the reservoir chamber 52 through the base valve 54.
  • the rigid body axially moves from the retracted position to the extended position, fluid moves from the first working chamber 46 to the second working chamber 48 through the piston valve 70, and fluid moves from the reservoir chamber 52 to the second working chamber 48 through the base valve 54.
  • the reserve tube 50 extends circumferentially around the pressure tube 32 and extends axially from the first endcap 34 past the second endcap 36 to the second mount 68.
  • the reserve tube 50 includes the cylindrical portion 58, the bulged portion 60, and a basecap 78.
  • the reserve tube 50 can be an integral piece, i.e., made of a single, uniform piece of material with no seams, joints, fasteners, or adhesives holding it together.
  • the reserve tube 50 defines the reservoir chamber 52.
  • the reservoir chamber 52 is radially between the reserve tube 50 and the pressure tube 32, i.e., radially inside the reserve tube 50 and radially outside the pressure tube 32.
  • the reservoir chamber 52 extends from the first endcap 34 to the basecap 78.
  • the first endcap 34 extends radially outward from the pressure tube 32 to the reserve tube 50.
  • the reservoir chamber 52 extends between the second endcap 36 and the second mount 68.
  • the reservoir chamber 52 is sealed except for the base valve 54.
  • the reservoir chamber 52 and the working chamber 42 are together completely sealed from an environment outside the reserve tube 50, i.e., there are no fluid paths between the working chamber 42 or reservoir chamber 52 and the environment outside the reserve tube 50.
  • the cylindrical portion 58 extends axially from the first endcap 34 toward the second endcap 36 and extends to the bulged portion 60.
  • the cylindrical portion 58 extends concentrically around the pressure tube 32.
  • the cylindrical portion 58 has a cylindrical shape defining the axis A.
  • the cylindrical portion 58 has a circular cross-section orthogonal to the axis A, and the circular cross-section is projected from the first endcap 34 to the bulged portion 60 along the axis A.
  • the cylindrical portion 58 has an inner radius R cyi measured from the axis A to an inner surface of the cylindrical portion 58, i.e., to a surface facing inward to the reservoir chamber 52.
  • the steering damper assembly 30 includes a foam member 76 disposed in the reservoir chamber 52.
  • the foam member 76 extends circumferentially around the pressure tube 32, extends radially outward from the pressure tube 32 to the reserve tube 50, specifically to the cylindrical portion 58 of the reserve tube 50, and extends axially from the first endcap 34 toward the second endcap 36.
  • the foam member 76 is axially spaced from the bulged portion 60.
  • the foam member 76 can be a rubber, e.g., neoprene.
  • the bulged portion 60 extends axially from the cylindrical portion 58 to the basecap 78 of the reserve tube 50.
  • the bulged portion 60 extends circumferentially relative to the axis A completely around the second endcap 36, and the bulged portion 60 is spaced from the second endcap 36.
  • the bulged portion 60 includes the first circumferential section 62 and the second circumferential section 64. The circumferential sections extend axially from the cylindrical portion 58 to the basecap 78.
  • the first circumferential section 62 extends circumferentially partially around the axis A from the second circumferential section 64 to the second circumferential section 64, and the second circumferential section 64 extends circumferentially partially around the axis A from the first circumferential section 62 to the first circumferential section 62.
  • the first circumferential section 62 faces downward, and the second circumferential section 64 faces upward; in other words, the first circumferential section 62 is disposed below the pressure tube 32, and the second circumferential section 64 is disposed above the pressure tube 32.
  • the bulged portion 60 has a constant cross- sectional shape projected along the axis A from the cylindrical portion 58 to the basecap 78.
  • the cross-sectional shape includes a first arc of circle 80 at least partially defining the first circumferential section 62, a second arc of circle 82 at least partially defining the second circumferential section 64, a first straight line 84 extending from the first arc of circle 80 to the second arc of circle 82, and a second straight line 86 extending from the first arc of circle 80 to the second arc of circle 82.
  • the straight lines 84, 86 connect tangentially to the arcs of circle 80, 82.
  • the cross-sectional shape can have a constant wall thickness following the first arc of circle 80, the second arc of circle 82, the first straight line 84, and the second straight line 86, as shown in Figures 4 and 5.
  • the cross-sectional shape can have a nonuniform wall thickness following the first arc of circle 80, the second arc of circle 82, the first straight line 84, and the second straight line 86.
  • the first arc of circle 80 can define the first circumferential section 62
  • the second arc of circle 82 and the straight lines 84, 86 can define the second circumferential section 64.
  • the first circumferential section 62 has a maximum radial distance Lbuii from the axis A at most equal to the inner radius R cyi of the cylindrical portion 58, e.g., as shown in Figure 4, equal to the inner radius R cy i.
  • the second circumferential section 64 has a maximum radial distance Lbui 2 from the axis A greater than the inner radius R cyi of the cylindrical portion 58, e.g., greater than twice the inner radius Rcyi.
  • the second mount 68 provides a location to attach the steering damper assembly 30 to the steering system.
  • the second mount 68 can permit rotation in one or more dimensions of the steering damper assembly 30 relative to the component of the steering system to which the second mount 68 is attached.
  • the second mount 68 can be a pin joint, ball joint, etc.
  • the second mount 68, the reserve tube 50, and the pressure tube 32 together form a rigid body.
  • the first mount 66, the piston rod 56, the piston assembly 44, and the dust shield 74 move axially together relative to the second mount 68, the reserve tube 50, and the pressure tube 32.
  • the dust shield 74 is fixed relative to the piston rod 56 and extends from the piston rod 56.
  • the dust shield 74 includes a conical portion 88 and a cylindrical portion 90.
  • the conical portion 88 extends radially outward from the piston rod 56 at the first mount 66, and the conical portion 88 extends axially from the first mount 66 toward the second mount 68.
  • the cylindrical portion 90 extends from the conical portion 88 away from the first mount 66 toward the second mount 68.
  • the cylindrical portion 90 of the dust shield 74 extends circumferentially around the cylindrical portion 58 of the reserve tube 50.
  • the cylindrical portion 90 of the dust shield 74 has a cylindrical shape positioned concentrically around the cylindrical portion 58 of the reserve tube 50, i.e., centered around the axis A.
  • the end of the cylindrical portion 90 of the dust shield 74 axially closest to the second mount 68 is not directly attached to any other components of the steering damper assembly 30.
  • An inner radius Rdust of the cylindrical portion 90 of the dust shield 74 can be smaller than the maximum radial distance Lbuii from the axis A to the second circumferential section 64 of the bulged portion 60 of the reserve tube 50, as shown in Figure 4.
  • the bulged portion 60 can extend outside of the inner radius Rdust of the dust shield 74, as shown in Figure 4, or the bulged portion 60 can extend no farther than the inner radius Rdust of the dust shield 74, as shown in Figure 5.
  • the dust shield 74 is axially movable relative to the pressure tube 32 between the retracted position and the extended position, along with the first mount 66, the piston rod 56, and the piston assembly 44.
  • the dust shield 74 in the extended position exposes a portion, e.g., more than half of an axial length, of the cylindrical portion 58 of the reserve tube 50, and the dust shield 74 in the extended position exposes the bulged portion 60 of the reserve tube 50.
  • the dust shield 74 in the retracted position as shown in Figure 3, mostly or entirely covers, e.g., covers more than half of an axial length of, the cylindrical portion 58 of the reserve tube 50.
  • the dust shield 74 in the retracted position exposes the bulged portion 60 of the reserve tube 50.
  • the dust shield 74 exposes the bulged portion 60 of the reserve tube 50 regardless of the position of the dust shield 74.
  • the dust shield 74 in the retracted position can cover the cylindrical portion 58 of the reserve tube 50 and can at least partially cover the bulged portion 60 of the reserve tube 50.
  • the steering damper assembly 30 includes oil 92 as a working fluid.
  • the oil 92 fills the working chamber 42 and fills a majority of the reservoir chamber 52.
  • the oil 92 fills the reservoir chamber 52 between the pressure tube 32 and the cylindrical portion 58 of the reserve tube 50, and the oil 92 incompletely fills the reservoir chamber 52 between the pressure tube 32 and the bulged portion 60 of the reserve tube 50; in particular, the oil 92 fills the reservoir chamber 52 between the first circumferential section 62 and extends above the pressure tube 32 in the second circumferential section 64 but leaves an air pocket 94 at a top of the second circumferential section 64. If air is introduced to the reservoir chamber 52, the air will travel through the oil 92, which is denser, to the air pocket 94, which is at
  • the first endcap 34 is a unitary piece.
  • the first endcap 34 includes a first portion 96 and a second portion 98.
  • the first portion 96 and the second portion 98 are axially adjacent each other.
  • the first portion 96 has a tubular shape centered on the axis A
  • the second portion 98 has a tubular shape centered on the axis A.
  • the largest outer diameter of the second portion 98 is greater than the largest outer diameter of the first portion 96.
  • the first endcap 34 includes a corner 100 extending in a circle concentrically around the axis A.
  • the first portion 96 and the second portion 98 meet at the corner 100.
  • the first endcap 34 includes a tunnel 102 centered on the axis and extending axially fully through the first endcap 34.
  • the first portion 96 includes a first cylindrical outer surface 104 axially adjacent the comer 100, a second cylindrical outer surface 106 axially adjacent to the first cylindrical outer surface 104, and a first frustoconical outer surface 108 axially adjacent to the second cylindrical outer surface 106.
  • the first cylindrical outer surface 104 extends axially from the corner 100 to the second cylindrical outer surface 106, and the second cylindrical outer surface 106 extends axially from the first cylindrical outer surface 104 to the first frustoconical outer surface 108.
  • the first cylindrical outer surface 104 has a diameter greater than a diameter of the second cylindrical outer surface 106.
  • the first portion 96 includes, e.g., a chamfer 110 connecting the first cylindrical outer surface 104 and the second cylindrical outer surface 106.
  • the first frustoconical outer surface 108 extends axially and radially inward from the second cylindrical outer surface 106.
  • the second portion 98 includes a radial surface 112, a second frustoconical outer surface 114, and a third cylindrical outer surface 116.
  • the second portion 98 includes a recess 118 extending along an entirety of the comer 100.
  • the recess 118 extends into the radial surface 112.
  • the radial surface 112 is flat and extends radially outward from the recess 118.
  • the second frustoconical outer surface 114 extends axially and radially outward from the radial surface 112 to the third cylindrical outer surface 116.
  • the third cylindrical outer surface 116 extends axially from the second frustoconical outer surface 114.
  • the second portion 98 includes a plurality of cutouts 120, e.g., six cutouts 120.
  • the cutouts 120 extend axially into the second frustoconical outer surface 114 and the third cylindrical outer surface 116.
  • the cutouts 120 are evenly spaced circumferentially around the axis A.
  • the cutouts 120 can provide a flow path for small-volume flow through the tunnel 102 past a bearing (not shown) holding the piston rod 56 and then radially outward past a seal (not shown) to the cutouts 120.
  • the tubular wall 40 axially abuts the radial surface 112.
  • the tubular wall 40 can contact and form an interference fit with the first cylindrical outer surface 104.
  • the cylindrical portion 58 of the reserve tube 50 extends around and contacts the third cylindrical outer surface 116.
  • the first cylindrical outer surface 104 includes a plurality of axial grooves 122, e.g., eight.
  • Each axial groove 122 is elongated parallel to the axis A from a first end 124 located at the chamfer 110 to a second end 126 located at the recess 118.
  • Each first end 124 is open to the working chamber 42, specifically the first working chamber 46.
  • Each second end 126 is open to the recess 118.
  • Each axial groove 122 can have a V-shaped cross-sectional shape orthogonal to the direction of elongation, and the cross- sectional shape can be uniform from the first end 124 to the second end 126.
  • the axial grooves 122 can be evenly spaced circumferentially around the axis A.
  • the radial surface 112 includes at least one radial groove 128, e.g., two or three.
  • the number of axial grooves 122 is greater than the number of radial grooves 128.
  • Each radial groove 128 is circumferentially offset from the axial grooves 122 about the axis A.
  • Each radial groove 128 is elongated from a first end 130 located at the recess 118 to a second end 132 located at an outer edge of the radial surface 112.
  • Each radial groove 128 extends from inside the tubular wall 40 to outside the tubular wall 40.
  • the first end 130 is open to the recess 118.
  • Each radial groove 128 can have a V- shaped cross-sectional shape orthogonal to the direction of elongation, and the cross-sectional shape can be uniform from the first end 130 to the second end 132.
  • Each radial groove 128 can extend upward from the recess 118 when the steering damper assembly 30 is installed.
  • Each radial groove 128 can extend in the same radial direction from the axis A as the first circumferential portion 62 of the bulged portion 60 of the reserve tube 50.
  • the axial grooves 122, the recess 118, and the at least one radial groove 128 provide a path for air to travel from the working chamber 42 to the reservoir chamber 52. As the piston assembly 44 moves back and forth in the working chamber 42, air can be worked out of the working chamber 42 into the reservoir chamber 52. In combination with the bulged portion 60, the path provided by the axial grooves 122, the recess 118, and the at least one radial groove 128 can effectively manage air inside the steering damper assembly 30. Once air travels from the working chamber 42 to the reservoir chamber 52, the air can travel to the bulged portion 60, which can prevent the air from reentering the working chamber 42.
  • Orienting the at least one radial groove 128 upward can improve the efficiency with which air travels from the working chamber 42 to the reservoir chamber 52.
  • the steering damper assembly 30 can expel air in fewer strokes of the piston assembly 44 because of the orientation.
  • the steering damper assembly 30 includes the basecap 78.
  • the basecap 78 contacts the second endcap 36 and the reserve tube 50.
  • the basecap 78 can be a separate component from the reserve tube 50.
  • the basecap 78 is generally disc shaped and is centered on the axis A.
  • the second mount 68 is attached to the basecap 78.
  • the basecap 78 includes a contacting surface 134.
  • the contacting surface 134 faces toward the working chamber 42 and first mount 66 along the axis A, and the contacting surface 134 faces away from the second mount 68 along the axis A.
  • the contacting surface 134 contacts, e.g., abuts, the second endcap 36.
  • the contacting surface 134 can be spaced from the axis A.
  • the contacting surface 134 extends circumferentially partially around the axis A, e.g., more than 180°, e.g., approximately 270°.
  • the basecap 78 includes a central surface 136.
  • the central surface 136 faces toward the working chamber 42 and first mount 66 along the axis A, and the central surface 134 faces away from the second mount 68 along the axis A.
  • the central surface 136 is spaced from the second endcap 36.
  • the central surface 136 is farther from the second endcap 36 along the axis A than the contacting surface 134 is.
  • the central surface 136 extends radially inward from the contacting surface 134 to the axis A.
  • the basecap 78 includes a recessed surface 138.
  • the recessed surface 138 faces toward the working chamber 42 and first mount 66 along the axis A, and the contacting surface 134 faces away from the second mount 68 along the axis A.
  • the recessed surface 138 is spaced from the second endcap 36.
  • the recessed surface 138 is farther from the second endcap 36 along the axis A than the contacting surface 134 is.
  • the recessed surface 138 extends circumferentially from the contacting surface 134 to the contacting surface 138, at a same radial distance from the axis A as the contacting surface 134.
  • the recessed surface 138 also extends radially outward from the central surface 136.
  • the recessed surface 138 is positioned vertically downward from the axis A.
  • the recessed surface 138 is positioned in an opposite direction from the axis A as the second circumferential section 64 of the bulged portion 60, e.g., the second circumferential section 64 is vertically upward from the axis A and the recessed surface 138 is vertically downward from the axis A.
  • the recessed surface 138 is positioned in an opposite direction from the axis A as the at least one radial groove 128, i.e., the at least one radial groove 128 is positioned vertically upward from the axis A and the recessed surface 138 is vertically downward from the axis A.
  • the basecap 78 and the second endcap 36 form a seal 140 extending circumferentially partially around the axis A.
  • the contacting surface 134 forms the seal 140 with the second endcap 36.
  • the seal 140 formed by the basecap 78 and the second endcap 36 extends circumferentially more than 180° around the axis A.
  • the basecap 78 forms the seal 140 with the second endcap 36 by the contacting surface 134 continuously contacting the second endcap 36 circumferentially around the axis A more than 180°.
  • the seal 140 extends less than 360° around the axis A.
  • the seal 140 extends from the recessed surface 138 circumferentially around the axis A to the recessed surface 138.
  • the seal 140 prevents fluid, e.g., oil 92, or air bubbles from flowing from the region between the second endcap 36 and the central surface 136 to the reservoir chamber 52 radially outside the second endcap 36.
  • fluid e.g., oil 92
  • the orientation of the recessed surface 138 i.e., that the recessed surface 138 is downward from the axis A, can prevent air in the reservoir chamber 52 from being pulled through the base valve 54 into the working chamber 42 when the piston assembly 44 moves from the retracted position to the extended position. Air tends to rise to the top of the reservoir chamber 52, and the orientation of the recessed surface 138 downward helps ensure that pure fluid, e.g., pure oil 92, is drawn into the working chamber 42.
  • This orientation of the recessed surface 138 downward can improve the efficiency with which air travels from the working chamber 42 to the reservoir chamber 52 by preventing backflow of air, especially when combined with the second circumferential section 64 of the bulged portion 60 and/or the recess 118 and grooves 122, 128.

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Abstract

A steering damper assembly (30) includes a cylindrical pressure tube (32) defining a working chamber (42); a piston assembly (44) disposed in the working chamber (42); a reserve tube (50) extending circumferentially around the pressure tube (32) and defining a reservoir chamber (52) that is radially between the reserve tube (50) and the pressure tube (32); a base valve (54) fluidly connecting the working chamber (42) and the reservoir chamber (52); and a piston rod (56) fixed to the piston assembly (44). The first endcap (34) includes a cylindrical outer surface (96), a radial surface (112) extending radially outward from the cylindrical outer surface (96), and a recess (118) between the cylindrical outer surface (96) and the radial surface (112). The tubular wall (40) contacts the cylindrical outer surface (96) and abuts the radial surface (112). The cylindrical outer surface (96) includes at least one axial groove (112) extending to the recess (118). The radial surface (112) includes at least one radial groove (128) extending to the recess (118).

Description

STEERING DAMPER ASSEMBLY
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This patent application claims priority to and all the benefits of U.S. Patent Application No. 16/674,608 filed on November 5, 2019, U.S. Provisional Patent Application No. 62/932,122 filed on November 7, 2019, and U.S. Provisional Patent Application No. 63/109,651 filed on November 4, 2020 which applications are herein incorporated by reference in their entireties.
BACKGROUND
[0002] Vehicles typically include steering systems. During operation of a vehicle, the steering system can be subject to vibrations and shocks from the driving surface. Some steering systems include a steering damper or steering stabilizer to absorb or dampen the vibrations and shocks from the driving surface.
BRIEF DESCRIPTION OF THE DRAWINGS [0003] Figure l is a perspective view of an example steering damper assembly.
[0004] Figure 2 is a side cross-sectional view of the steering damper assembly with a piston in an extended position.
[0005] Figure 3 is a side cross-sectional view of the steering damper assembly with the piston in a retracted position.
[0006] Figure 4 is a front cross-sectional view of the steering damper.
[0007] Figure 5 is a front cross-sectional view of another example of the steering damper.
[0008] Figure 6 is rear plan view of a first endcap of the steering damper.
[0009] Figure 7 is a side view of the first endcap.
[0010] Figure 8 is a front plan view of the first endcap.
[0011] Figure 9 is side cross-sectional view of the first endcap along line 9-9 in Figure 6.
[0012] Figure 10 is a cross-sectional view of a portion of the first endcap along line 10-10 in Figure 6.
[0013] Figure 11 is a side cross-sectional view of the first endcap along line 11-11 in Figure 7.
[0014] Figure 12 is a cross-sectional view of a portion of the first endcap along line 12-12 in Figure 3.
[0015] Figure 13 is a cross-sectional view of a portion of the first endcap along line 13-13 in Figure 3. [0016] Figure 14 is a perspective view of a portion of the first endcap.
[0017] Figure 15 is a side cross-sectional view of a portion of the steering damper assembly with a basecap.
[0018] Figure 16 is a plan view of the basecap.
[0019] Figure 17 is a perspective view of the basecap.
DETAILED DESCRIPTION
[0020] With reference to the Figures, a steering damper assembly 30 includes a cylindrical pressure tube 32 including a first endcap 34, a second endcap 36, and a tubular wall 40 defining and extending along an axis A from the first endcap 34 to the second endcap 36, the pressure tube 32 defining a working chamber 42; a piston assembly 44 disposed in the working chamber 42 and dividing the working chamber 42 into a first working chamber 46 adjacent the first endcap 34 and a second working chamber 48 adjacent the second endcap 36; a reserve tube 50 extending circumferentially around the pressure tube 32 and defining a reservoir chamber 52 that is radially between the reserve tube 50 and the pressure tube 32; a base valve 54 fluidly connecting and controlling flow between the second working chamber 48 and the reservoir chamber 52; and a piston rod 56 fixed to the piston assembly 44 and extending through the first endcap 34 of the pressure tube 32. The reserve tube 50 includes a cylindrical portion 58 and a bulged portion 60. The cylindrical portion 58 extends from the first endcap 34 of the pressure tube 32 toward the second endcap 36 of the pressure tube 32 and extends concentrically around the pressure tube 32, the cylindrical portion 58 having an inner radius R yi from the axis A. The bulged portion 60 includes a first circumferential section 62 and a second circumferential section 64, the first circumferential section 62 having a maximum radial distance Lbuii from the axis A at most equal to the inner radius Rcyi of the cylindrical portion 58, and the second circumferential section 64 having a maximum radial distance Lbui 2 from the axis A greater than the inner radius Rcyi of the cylindrical portion 58.
[0021] The steering damper assembly 30 provides a way to mitigate negative effects of air introduced into the reservoir chamber 52. The bulged portion 60 of the reserve tube 50 provides a location for air in the reservoir chamber 52 to go, which can prevent the air from traveling into the working chamber 42. Air in the working chamber 42 can cause lagging in the absorption or dampening of shocks and vibrations. Moreover, the shape of the reserve tube 50 with the cylindrical portion 58 and the bulged portion 60 provides an easy-to-manufacture design using a small number of parts and a small amount of material. Finally, the steering damper assembly 30 has a compact shape, which helps packaging in a steering system of a vehicle.
[0022] With reference to Figure 1, the steering damper assembly 30 is mountable to the steering system of the vehicle (not shown). The steering damper assembly 30 includes a first mount 66 and a second mount 68. The mounts 66, 68 are each attachable to a point on the vehicle. For example, one of the mounts 66, 68 can be attached to a point that is fixed relative to a body of the vehicle, and the other of the mounts 66, 68 can be attached to a point that moves with components of the steering system relative to the body of the vehicle. When mounted, the steering damper assembly 30 is oriented generally horizontally, specifically, such that the axis A is oriented generally horizontally. The steering damper assembly 30, also referred to as a steering stabilizer, can absorb vibrations and shocks transmitted through the steering system.
[0023] With reference to Figures 2 and 3, the pressure tube 32 has a cylindrical shape defining the axis A. The pressure tube 32 includes the first endcap 34, the second endcap 36, and the tubular wall 40. The first endcap 34 and the second endcap 36 each have a circular shape centered on the axis A. The tubular wall 40 has a circular cross-section orthogonal to the axis A, and the circular cross-section is projected from the first endcap 34 to the second endcap 36. The first endcap 34 and the second endcap 36 extend radially inward from the tubular wall 40 toward the axis A. The first endcap 34, the second endcap 36, and the tubular wall 40 are attached to and fixed relative to each other.
[0024] The pressure tube 32 defines the working chamber 42. The working chamber 42 is contained within the pressure tube 32. The working chamber 42 is sealed such that fluid can only flow into or out of the working chamber 42 through the base valve 54.
[0025] The piston assembly 44 is disposed in the working chamber 42. The piston assembly 44 has a circular cross-section centered on the axis A and forming a seal with the tubular wall 40. The piston assembly 44 contacts and forms a seal with the tubular wall 40 circumferentially for 360° around the axis A. The piston assembly 44 divides the working chamber 42 into the first working chamber 46 and the second working chamber 48. The first working chamber 46 is adjacent the first endcap 34 and is enclosed by the first endcap 34, the tubular wall 40, and the piston assembly 44. The second working chamber 48 is adjacent the second endcap 36 and is enclosed by the second endcap 36, the tubular wall 40, and the piston assembly 44.
[0026] The piston assembly 44 includes a piston valve 70. The piston valve 70 permits flow between the first working chamber 46 and the second working chamber 48, i.e., through the piston assembly 44, as the piston assembly 44 moves axially, i.e., translates along the axis A. As the piston assembly 44 and piston rod 56 move axially toward the second endcap 36, the piston valve 70 permits flow of fluid out of the second working chamber 48 into the first working chamber 46 to compensate for the relative change in volume between the first working chamber 46 and the second working chamber 48, and as the piston assembly 44 and piston rod 56 move axially toward the first endcap 34, the base valve 54 permits flow of fluid into the second working chamber 48 from the first working chamber 46 to compensate for the relative change in volume between the first working chamber 46 and the second working chamber 48. The piston valve 70 can be sized to permit a defined rate of flow between the first working chamber 46 and the second working chamber 48.
[0027] The piston rod 56 is fixed to the piston assembly 44. The piston rod 56 extends from the piston assembly 44 to and through the first endcap 34 of the pressure tube 32. The piston rod 56 is disposed partially inside the first working chamber 46 and partially outside the pressure tube 32. The piston rod 56 has a constant cross-section that is projected from the piston assembly 44 through the first endcap 34 to the first mount 66. The piston assembly 44, the piston rod 56, and the first mount 66 are attached to and fixed relative to each other.
[0028] The first endcap 34 includes a first-endcap seal 72 extending circumferentially around the piston rod 56 and forming a seal with the piston rod 56. The first-endcap seal 72 prevents fluid in the first working chamber 46 from leaking out of the pressure tube 32 along the piston rod 56.
[0029] The base valve 54 fluidly connects and controls flow between the second working chamber 48 and the reservoir chamber 52. The base valve 54 extends through the second endcap 36. As the piston assembly 44 and piston rod 56 move axially toward the second endcap 36, the base valve 54 permits flow of fluid out of the second working chamber 48 into the reservoir chamber 52 to compensate for the additional volume in the working chamber 42 occupied by the piston rod 56, and as the piston assembly 44 and piston rod 56 move axially toward the first endcap 34, the base valve 54 permits flow of fluid into the second working chamber 48 from the reservoir chamber 52 to compensate for the reduction in volume in the working chamber 42 occupied by the piston rod 56. The base valve 54 can be sized to permit a defined rate of flow between the second working chamber 48 and the reservoir chamber 52. [0030] The first mount 66 provides a location to attach the steering damper assembly 30 to a steering system. The first mount 66 can permit rotation in one or more dimensions of the steering damper assembly 30 relative to the component of the steering system to which the first mount 66 is attached. For example, the first mount 66 can be a pin joint, ball joint, etc. [0031] The first mount 66, the piston rod 56, the piston assembly 44, and a dust shield 74 (described below) together form a rigid body, i.e., are connected to each other and fixed relative to each other. The first mount 66, the piston rod 56, the piston assembly 44, and the dust shield 74 are axially movable together relative to the pressure tube 32 between a retracted position with the piston assembly 44 at a closest position to the second endcap 36, as shown in Figure 3, and an extended position with the piston assembly 44 at a farthest position from the second endcap 36, as shown in Figure 2. As the rigid body axially moves from the extended position to the retracted position, fluid moves from the second working chamber 48 to the first working chamber 46 through the piston valve 70, and fluid moves from the second working chamber 48 to the reservoir chamber 52 through the base valve 54. As the rigid body axially moves from the retracted position to the extended position, fluid moves from the first working chamber 46 to the second working chamber 48 through the piston valve 70, and fluid moves from the reservoir chamber 52 to the second working chamber 48 through the base valve 54.
[0032] The reserve tube 50 extends circumferentially around the pressure tube 32 and extends axially from the first endcap 34 past the second endcap 36 to the second mount 68. The reserve tube 50 includes the cylindrical portion 58, the bulged portion 60, and a basecap 78. The reserve tube 50 can be an integral piece, i.e., made of a single, uniform piece of material with no seams, joints, fasteners, or adhesives holding it together.
[0033] The reserve tube 50 defines the reservoir chamber 52. The reservoir chamber 52 is radially between the reserve tube 50 and the pressure tube 32, i.e., radially inside the reserve tube 50 and radially outside the pressure tube 32. The reservoir chamber 52 extends from the first endcap 34 to the basecap 78. The first endcap 34 extends radially outward from the pressure tube 32 to the reserve tube 50. The reservoir chamber 52 extends between the second endcap 36 and the second mount 68. The reservoir chamber 52 is sealed except for the base valve 54. The reservoir chamber 52 and the working chamber 42 are together completely sealed from an environment outside the reserve tube 50, i.e., there are no fluid paths between the working chamber 42 or reservoir chamber 52 and the environment outside the reserve tube 50. [0034] The cylindrical portion 58 extends axially from the first endcap 34 toward the second endcap 36 and extends to the bulged portion 60. The cylindrical portion 58 extends concentrically around the pressure tube 32. The cylindrical portion 58 has a cylindrical shape defining the axis A. The cylindrical portion 58 has a circular cross-section orthogonal to the axis A, and the circular cross-section is projected from the first endcap 34 to the bulged portion 60 along the axis A. The cylindrical portion 58 has an inner radius Rcyi measured from the axis A to an inner surface of the cylindrical portion 58, i.e., to a surface facing inward to the reservoir chamber 52.
[0035] The steering damper assembly 30 includes a foam member 76 disposed in the reservoir chamber 52. The foam member 76 extends circumferentially around the pressure tube 32, extends radially outward from the pressure tube 32 to the reserve tube 50, specifically to the cylindrical portion 58 of the reserve tube 50, and extends axially from the first endcap 34 toward the second endcap 36. The foam member 76 is axially spaced from the bulged portion 60. The foam member 76 can be a rubber, e.g., neoprene.
[0036] The bulged portion 60 extends axially from the cylindrical portion 58 to the basecap 78 of the reserve tube 50. The bulged portion 60 extends circumferentially relative to the axis A completely around the second endcap 36, and the bulged portion 60 is spaced from the second endcap 36. The bulged portion 60 includes the first circumferential section 62 and the second circumferential section 64. The circumferential sections extend axially from the cylindrical portion 58 to the basecap 78. The first circumferential section 62 extends circumferentially partially around the axis A from the second circumferential section 64 to the second circumferential section 64, and the second circumferential section 64 extends circumferentially partially around the axis A from the first circumferential section 62 to the first circumferential section 62. When the steering damper assembly 30 is mounted to the steering system, the first circumferential section 62 faces downward, and the second circumferential section 64 faces upward; in other words, the first circumferential section 62 is disposed below the pressure tube 32, and the second circumferential section 64 is disposed above the pressure tube 32.
[0037] With reference to Figures 4 and 5, the bulged portion 60 has a constant cross- sectional shape projected along the axis A from the cylindrical portion 58 to the basecap 78. The cross-sectional shape includes a first arc of circle 80 at least partially defining the first circumferential section 62, a second arc of circle 82 at least partially defining the second circumferential section 64, a first straight line 84 extending from the first arc of circle 80 to the second arc of circle 82, and a second straight line 86 extending from the first arc of circle 80 to the second arc of circle 82. The straight lines 84, 86 connect tangentially to the arcs of circle 80, 82. The cross-sectional shape can have a constant wall thickness following the first arc of circle 80, the second arc of circle 82, the first straight line 84, and the second straight line 86, as shown in Figures 4 and 5. Alternatively, the cross-sectional shape can have a nonuniform wall thickness following the first arc of circle 80, the second arc of circle 82, the first straight line 84, and the second straight line 86. The first arc of circle 80 can define the first circumferential section 62, and the second arc of circle 82 and the straight lines 84, 86 can define the second circumferential section 64. The first circumferential section 62 has a maximum radial distance Lbuii from the axis A at most equal to the inner radius Rcyi of the cylindrical portion 58, e.g., as shown in Figure 4, equal to the inner radius Rcyi. The second circumferential section 64 has a maximum radial distance Lbui 2 from the axis A greater than the inner radius Rcyi of the cylindrical portion 58, e.g., greater than twice the inner radius Rcyi. [0038] Returning to Figures 2 and 3, the second mount 68 provides a location to attach the steering damper assembly 30 to the steering system. The second mount 68 can permit rotation in one or more dimensions of the steering damper assembly 30 relative to the component of the steering system to which the second mount 68 is attached. For example, the second mount 68 can be a pin joint, ball joint, etc. The second mount 68, the reserve tube 50, and the pressure tube 32 together form a rigid body. The first mount 66, the piston rod 56, the piston assembly 44, and the dust shield 74 move axially together relative to the second mount 68, the reserve tube 50, and the pressure tube 32.
[0039] The dust shield 74 is fixed relative to the piston rod 56 and extends from the piston rod 56. The dust shield 74 includes a conical portion 88 and a cylindrical portion 90. The conical portion 88 extends radially outward from the piston rod 56 at the first mount 66, and the conical portion 88 extends axially from the first mount 66 toward the second mount 68. The cylindrical portion 90 extends from the conical portion 88 away from the first mount 66 toward the second mount 68. The cylindrical portion 90 of the dust shield 74 extends circumferentially around the cylindrical portion 58 of the reserve tube 50. The cylindrical portion 90 of the dust shield 74 has a cylindrical shape positioned concentrically around the cylindrical portion 58 of the reserve tube 50, i.e., centered around the axis A. The end of the cylindrical portion 90 of the dust shield 74 axially closest to the second mount 68 is not directly attached to any other components of the steering damper assembly 30. An inner radius Rdust of the cylindrical portion 90 of the dust shield 74 can be smaller than the maximum radial distance Lbuii from the axis A to the second circumferential section 64 of the bulged portion 60 of the reserve tube 50, as shown in Figure 4. The bulged portion 60 can extend outside of the inner radius Rdust of the dust shield 74, as shown in Figure 4, or the bulged portion 60 can extend no farther than the inner radius Rdust of the dust shield 74, as shown in Figure 5.
[0040] The dust shield 74 is axially movable relative to the pressure tube 32 between the retracted position and the extended position, along with the first mount 66, the piston rod 56, and the piston assembly 44. The dust shield 74 in the extended position, as shown in Figure 2, exposes a portion, e.g., more than half of an axial length, of the cylindrical portion 58 of the reserve tube 50, and the dust shield 74 in the extended position exposes the bulged portion 60 of the reserve tube 50. The dust shield 74 in the retracted position, as shown in Figure 3, mostly or entirely covers, e.g., covers more than half of an axial length of, the cylindrical portion 58 of the reserve tube 50. In one example, with the cross-sectional shape of the bulged portion 60 shown in Figure 4, the dust shield 74 in the retracted position exposes the bulged portion 60 of the reserve tube 50. In other words, the dust shield 74 exposes the bulged portion 60 of the reserve tube 50 regardless of the position of the dust shield 74. In another example, with the cross-sectional shape of the bulged portion 60 shown in Figure 5, the dust shield 74 in the retracted position can cover the cylindrical portion 58 of the reserve tube 50 and can at least partially cover the bulged portion 60 of the reserve tube 50.
[0041] With reference to Figures 2-5, the steering damper assembly 30 includes oil 92 as a working fluid. The oil 92 fills the working chamber 42 and fills a majority of the reservoir chamber 52. When the steering damper assembly 30 is oriented so that the axis A is oriented horizontally and the second circumferential section 64 faces upward, e.g., when the steering damper assembly 30 is installed in the steering system, the oil 92 fills the reservoir chamber 52 between the pressure tube 32 and the cylindrical portion 58 of the reserve tube 50, and the oil 92 incompletely fills the reservoir chamber 52 between the pressure tube 32 and the bulged portion 60 of the reserve tube 50; in particular, the oil 92 fills the reservoir chamber 52 between the first circumferential section 62 and extends above the pressure tube 32 in the second circumferential section 64 but leaves an air pocket 94 at a top of the second circumferential section 64. If air is introduced to the reservoir chamber 52, the air will travel through the oil 92, which is denser, to the air pocket 94, which is at a highest location of the reservoir chamber 52, rather than possibly traveling into the working chamber 42.
[0042] With reference to Figures 6-11, the first endcap 34 is a unitary piece. The first endcap 34 includes a first portion 96 and a second portion 98. The first portion 96 and the second portion 98 are axially adjacent each other. The first portion 96 has a tubular shape centered on the axis A, and the second portion 98 has a tubular shape centered on the axis A. The largest outer diameter of the second portion 98 is greater than the largest outer diameter of the first portion 96. The first endcap 34 includes a corner 100 extending in a circle concentrically around the axis A. The first portion 96 and the second portion 98 meet at the corner 100. The first endcap 34 includes a tunnel 102 centered on the axis and extending axially fully through the first endcap 34.
[0043] The first portion 96 includes a first cylindrical outer surface 104 axially adjacent the comer 100, a second cylindrical outer surface 106 axially adjacent to the first cylindrical outer surface 104, and a first frustoconical outer surface 108 axially adjacent to the second cylindrical outer surface 106. The first cylindrical outer surface 104 extends axially from the corner 100 to the second cylindrical outer surface 106, and the second cylindrical outer surface 106 extends axially from the first cylindrical outer surface 104 to the first frustoconical outer surface 108. The first cylindrical outer surface 104 has a diameter greater than a diameter of the second cylindrical outer surface 106. The first portion 96 includes, e.g., a chamfer 110 connecting the first cylindrical outer surface 104 and the second cylindrical outer surface 106. The first frustoconical outer surface 108 extends axially and radially inward from the second cylindrical outer surface 106.
[0044] The second portion 98 includes a radial surface 112, a second frustoconical outer surface 114, and a third cylindrical outer surface 116. The second portion 98 includes a recess 118 extending along an entirety of the comer 100. The recess 118 extends into the radial surface 112. The radial surface 112 is flat and extends radially outward from the recess 118. The second frustoconical outer surface 114 extends axially and radially outward from the radial surface 112 to the third cylindrical outer surface 116. The third cylindrical outer surface 116 extends axially from the second frustoconical outer surface 114.
[0045] The second portion 98 includes a plurality of cutouts 120, e.g., six cutouts 120. The cutouts 120 extend axially into the second frustoconical outer surface 114 and the third cylindrical outer surface 116. The cutouts 120 are evenly spaced circumferentially around the axis A. The cutouts 120 can provide a flow path for small-volume flow through the tunnel 102 past a bearing (not shown) holding the piston rod 56 and then radially outward past a seal (not shown) to the cutouts 120.
[0046] The tubular wall 40 axially abuts the radial surface 112. The tubular wall 40 can contact and form an interference fit with the first cylindrical outer surface 104. The cylindrical portion 58 of the reserve tube 50 extends around and contacts the third cylindrical outer surface 116.
[0047] With reference to Figures 8 and 12-14, the first cylindrical outer surface 104 includes a plurality of axial grooves 122, e.g., eight. Each axial groove 122 is elongated parallel to the axis A from a first end 124 located at the chamfer 110 to a second end 126 located at the recess 118. Each first end 124 is open to the working chamber 42, specifically the first working chamber 46. Each second end 126 is open to the recess 118. Each axial groove 122 can have a V-shaped cross-sectional shape orthogonal to the direction of elongation, and the cross- sectional shape can be uniform from the first end 124 to the second end 126. The axial grooves 122 can be evenly spaced circumferentially around the axis A. [0048] The radial surface 112 includes at least one radial groove 128, e.g., two or three. The number of axial grooves 122 is greater than the number of radial grooves 128. Each radial groove 128 is circumferentially offset from the axial grooves 122 about the axis A. Each radial groove 128 is elongated from a first end 130 located at the recess 118 to a second end 132 located at an outer edge of the radial surface 112. Each radial groove 128 extends from inside the tubular wall 40 to outside the tubular wall 40. The first end 130 is open to the recess 118. The second end 132 is open to the reservoir chamber 52. Each radial groove 128 can have a V- shaped cross-sectional shape orthogonal to the direction of elongation, and the cross-sectional shape can be uniform from the first end 130 to the second end 132. Each radial groove 128 can extend upward from the recess 118 when the steering damper assembly 30 is installed. Each radial groove 128 can extend in the same radial direction from the axis A as the first circumferential portion 62 of the bulged portion 60 of the reserve tube 50.
[0049] The axial grooves 122, the recess 118, and the at least one radial groove 128 provide a path for air to travel from the working chamber 42 to the reservoir chamber 52. As the piston assembly 44 moves back and forth in the working chamber 42, air can be worked out of the working chamber 42 into the reservoir chamber 52. In combination with the bulged portion 60, the path provided by the axial grooves 122, the recess 118, and the at least one radial groove 128 can effectively manage air inside the steering damper assembly 30. Once air travels from the working chamber 42 to the reservoir chamber 52, the air can travel to the bulged portion 60, which can prevent the air from reentering the working chamber 42.
[0050] Orienting the at least one radial groove 128 upward can improve the efficiency with which air travels from the working chamber 42 to the reservoir chamber 52. The steering damper assembly 30 can expel air in fewer strokes of the piston assembly 44 because of the orientation.
[0051] With reference to Figures 15-17, the steering damper assembly 30 includes the basecap 78. The basecap 78 contacts the second endcap 36 and the reserve tube 50. The basecap 78 can be a separate component from the reserve tube 50. The basecap 78 is generally disc shaped and is centered on the axis A. The second mount 68 is attached to the basecap 78. [0052] The basecap 78 includes a contacting surface 134. The contacting surface 134 faces toward the working chamber 42 and first mount 66 along the axis A, and the contacting surface 134 faces away from the second mount 68 along the axis A. The contacting surface 134 contacts, e.g., abuts, the second endcap 36. The contacting surface 134 can be spaced from the axis A. The contacting surface 134 extends circumferentially partially around the axis A, e.g., more than 180°, e.g., approximately 270°. [0053] The basecap 78 includes a central surface 136. The central surface 136 faces toward the working chamber 42 and first mount 66 along the axis A, and the central surface 134 faces away from the second mount 68 along the axis A. The central surface 136 is spaced from the second endcap 36. The central surface 136 is farther from the second endcap 36 along the axis A than the contacting surface 134 is. The central surface 136 extends radially inward from the contacting surface 134 to the axis A.
[0054] The basecap 78 includes a recessed surface 138. The recessed surface 138 faces toward the working chamber 42 and first mount 66 along the axis A, and the contacting surface 134 faces away from the second mount 68 along the axis A. The recessed surface 138 is spaced from the second endcap 36. The recessed surface 138 is farther from the second endcap 36 along the axis A than the contacting surface 134 is. The recessed surface 138 extends circumferentially from the contacting surface 134 to the contacting surface 138, at a same radial distance from the axis A as the contacting surface 134. The recessed surface 138 also extends radially outward from the central surface 136.
[0055] When the steering damper assembly 30 is installed, the recessed surface 138 is positioned vertically downward from the axis A. The recessed surface 138 is positioned in an opposite direction from the axis A as the second circumferential section 64 of the bulged portion 60, e.g., the second circumferential section 64 is vertically upward from the axis A and the recessed surface 138 is vertically downward from the axis A. The recessed surface 138 is positioned in an opposite direction from the axis A as the at least one radial groove 128, i.e., the at least one radial groove 128 is positioned vertically upward from the axis A and the recessed surface 138 is vertically downward from the axis A.
[0056] The basecap 78 and the second endcap 36 form a seal 140 extending circumferentially partially around the axis A. Specifically, the contacting surface 134 forms the seal 140 with the second endcap 36. The seal 140 formed by the basecap 78 and the second endcap 36 extends circumferentially more than 180° around the axis A. The basecap 78 forms the seal 140 with the second endcap 36 by the contacting surface 134 continuously contacting the second endcap 36 circumferentially around the axis A more than 180°. The seal 140 extends less than 360° around the axis A. The seal 140 extends from the recessed surface 138 circumferentially around the axis A to the recessed surface 138. Along the circumferential extend of the seal 140, the seal 140 prevents fluid, e.g., oil 92, or air bubbles from flowing from the region between the second endcap 36 and the central surface 136 to the reservoir chamber 52 radially outside the second endcap 36. [0057] The orientation of the recessed surface 138, i.e., that the recessed surface 138 is downward from the axis A, can prevent air in the reservoir chamber 52 from being pulled through the base valve 54 into the working chamber 42 when the piston assembly 44 moves from the retracted position to the extended position. Air tends to rise to the top of the reservoir chamber 52, and the orientation of the recessed surface 138 downward helps ensure that pure fluid, e.g., pure oil 92, is drawn into the working chamber 42. This orientation of the recessed surface 138 downward can improve the efficiency with which air travels from the working chamber 42 to the reservoir chamber 52 by preventing backflow of air, especially when combined with the second circumferential section 64 of the bulged portion 60 and/or the recess 118 and grooves 122, 128.
[0058] The disclosure has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. The adjectives “first” and “second” are used throughout this document as identifiers and are not intended to signify importance, order, or quantity. Many modifications and variations of the present disclosure are possible in light of the above teachings, and the disclosure may be practiced otherwise than as specifically described.

Claims

CLAIMS What is claimed is:
1. A steering damper assembly comprising: a cylindrical pressure tube including a first endcap, a second endcap, and a tubular wall defining and extending along an axis from the first endcap to the second endcap, the pressure tube defining a working chamber; a piston assembly disposed in the working chamber and dividing the working chamber into a first working chamber adjacent the first endcap and a second working chamber adjacent the second endcap; a reserve tube extending circumferentially around the pressure tube and defining a reservoir chamber that is radially between the reserve tube and the pressure tube; a base valve fluidly connecting and controlling flow between the second working chamber and the reservoir chamber; and a piston rod fixed to the piston assembly and extending through the first endcap of the pressure tube; wherein the first endcap includes a cylindrical outer surface, a radial surface extending radially outward from the cylindrical outer surface, and a recess between the cylindrical outer surface and the radial surface; the tubular wall contacts the cylindrical outer surface and abuts the radial surface; the cylindrical outer surface includes at least one axial groove extending to the recess; and the radial surface includes at least one radial groove extending to the recess.
2. The steering damper assembly of claim 1, wherein the at least one radial groove is elongated from a first end open to the recess to a second end open to the reservoir chamber.
3. The steering damper assembly of claim 2, wherein a cross-sectional shape of the at least one radial groove is uniform from the first end to the second end.
4. The steering damper assembly of one of claims 1-3, wherein the at least one axial groove is elongated from a first end open to the working chamber to a second end open to the recess.
5. The steering damper assembly of claim 4, wherein a cross-sectional shape of the at least one axial groove is uniform from the first end to the second end.
6 The steering damper assembly of one of claims 1-5, wherein the at least one radial groove is circumferentially offset from the at least one axial groove.
7. The steering damper assembly of one of claims 1-6, wherein the at least one radial groove extends from inside the tubular wall to outside the tubular wall.
8. The steering damper assembly of one of claims 1-7, wherein the tubular wall forms an interference fit with the cylindrical outer surface.
9. The steering damper assembly of one of claims 1-8, wherein the recess extends into the radial surface.
10. The steering damper assembly of one of claims 1-9, wherein the cylindrical outer surface is a first cylindrical outer surface; the first endcap includes a first portion and a second portion; the first portion includes the cylindrical outer surface; the second portion includes the radial surface and a third cylindrical outer surface; the first portion and the second portion are axially adjacent each other; and the reserve tube extends around and contacts the third cylindrical outer surface.
11. The steering damper assembly of one of claims 1-10, wherein the reserve tube includes a cylindrical portion and a bulged portion; the cylindrical portion extends from the first endcap of the pressure tube toward the second endcap of the pressure tube and extends concentrically around the pressure tube, the cylindrical portion having an inner radius from the axis; and the bulged portion includes a first circumferential section and a second circumferential section, the first circumferential section having a maximum radial distance from the axis at most equal to the inner radius of the cylindrical portion, and the second circumferential section having a maximum radial distance from the axis greater than the inner radius of the cylindrical portion.
12. The steering damper assembly of claim 11, wherein the at least one radial groove extends in a same radial direction from the axis as the first circumferential portion of the bulged portion of the reserve tube.
13. The steering damper assembly of one of claims 1-12, further comprising a basecap contacting the second endcap and the reserve tube, wherein the base valve extends through the second endcap, and the basecap and the second endcap form a seal extending circumferentially partially around the axis.
14. The steering damper assembly of claim 13, wherein the seal formed by the basecap and the second endcap extends circumferentially more than 180° around the axis.
15. The steering damper assembly of claim 13 or 14, wherein the basecap includes a contacting surface forming the seal with the second endcap and a recessed surface spaced from the second endcap and extending from the contacting surface, and the recessed surface is positioned in an opposite direction from the axis as the at least one radial groove is.
16. A steering damper assembly comprising: a cylindrical pressure tube including a first endcap, a second endcap, and a tubular wall defining and extending along an axis from the first endcap to the second endcap, the pressure tube defining a working chamber; a piston assembly disposed in the working chamber and dividing the working chamber into a first working chamber adjacent the first endcap and a second working chamber adjacent the second endcap; a reserve tube extending circumferentially around the pressure tube and defining a reservoir chamber that is radially between the reserve tube and the pressure tube; a base valve fluidly connecting and controlling flow between the second working chamber and the reservoir chamber; and a piston rod fixed to the piston assembly and extending through the first endcap of the pressure tube; wherein the reserve tube includes a cylindrical portion and a bulged portion; the cylindrical portion extends from the first endcap of the pressure tube toward the second endcap of the pressure tube and extends concentrically around the pressure tube, the cylindrical portion having an inner radius from the axis; and the bulged portion includes a first circumferential section and a second circumferential section, the first circumferential section having a maximum radial distance from the axis at most equal to the inner radius of the cylindrical portion, and the second circumferential section having a maximum radial distance from the axis greater than the inner radius of the cylindrical portion.
17. The steering damper assembly of claim 16, further comprising a dust shield fixed relative to the piston rod and extending circumferentially around the cylindrical portion of the reserve tube.
18. The steering damper assembly of claim 17, wherein the dust shield is axially movable relative to the pressure tube with the piston rod between a retracted position and an extended position; and the dust shield in the extended position exposes a portion of the cylindrical portion of the reserve tube and exposes the bulged portion of the reserve tube.
19. The steering damper assembly of claim 18, wherein the dust shield in the retracted position exposes the bulged portion of the reserve tube.
20. The steering damper assembly of one of claims 16-19, further comprising a basecap contacting the second endcap and the reserve tube, wherein the base valve extends through the second endcap, the basecap and the second endcap form a seal extending circumferentially partially around the axis, the basecap includes a contacting surface forming the seal with the second endcap and a recessed surface spaced from the second endcap and extending from the contacting surface, and the recessed surface is positioned in an opposite direction from the axis as the second circumferential section of the bulged portion.
PCT/US2020/058923 2019-11-05 2020-11-04 Steering damper assembly WO2021092040A1 (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US16/674,608 2019-11-05
US16/674,608 US20210131523A1 (en) 2019-11-05 2019-11-05 Steering damper assembly with bulged portion
US201962932122P 2019-11-07 2019-11-07
US62/932,122 2019-11-07
US202063109651P 2020-11-04 2020-11-04
US63/109,651 2020-11-04

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB579390A (en) * 1943-11-04 1946-08-01 Monroe Auto Equipment Co Improvements in or relating to hydraulic shock absorbers
DE1146705B (en) * 1962-05-09 1963-04-04 Boge Gmbh Hydraulic twin-tube vibration damper with ventilation, especially for motor vehicles
DE7904259U1 (en) * 1979-02-16 1979-06-07 Fichtel & Sachs Ag, 8720 Schweinfurt Hydropneumatic twin-tube vibration damper with multi-part piston rod guide
GB2111637A (en) * 1981-11-04 1983-07-06 Woodhead Ltd Jonas Hydropneumatic shock absorbers with gas return passage
US20120048664A1 (en) * 2009-04-28 2012-03-01 Kayaba Industry Co., Ltd. Multi-cylinder hydraulic shock absorber
US20120091678A1 (en) * 2009-05-19 2012-04-19 Buettner Josef Stabilizing device for steered trailing axles of vehicles

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB579390A (en) * 1943-11-04 1946-08-01 Monroe Auto Equipment Co Improvements in or relating to hydraulic shock absorbers
DE1146705B (en) * 1962-05-09 1963-04-04 Boge Gmbh Hydraulic twin-tube vibration damper with ventilation, especially for motor vehicles
DE7904259U1 (en) * 1979-02-16 1979-06-07 Fichtel & Sachs Ag, 8720 Schweinfurt Hydropneumatic twin-tube vibration damper with multi-part piston rod guide
GB2111637A (en) * 1981-11-04 1983-07-06 Woodhead Ltd Jonas Hydropneumatic shock absorbers with gas return passage
US20120048664A1 (en) * 2009-04-28 2012-03-01 Kayaba Industry Co., Ltd. Multi-cylinder hydraulic shock absorber
US20120091678A1 (en) * 2009-05-19 2012-04-19 Buettner Josef Stabilizing device for steered trailing axles of vehicles

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