Classifications

• • 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
  • F16F9/50—Special means providing automatic damping adjustment, i.e. self-adjustment of damping by particular sliding movements of a valve element, other than flexions or displacement of valve discs; Special means providing self-adjustment of spring characteristics
  • F16F9/504—Inertia, i.e. acceleration,-sensitive means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
  • B60G17/06—Characteristics of dampers, e.g. mechanical dampers
  • B60G17/08—Characteristics of fluid dampers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2300/00—Indexing codes relating to the type of vehicle
  • B60G2300/07—Off-road vehicles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2300/00—Indexing codes relating to the type of vehicle
  • B60G2300/12—Cycles; Motorcycles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2500/00—Indexing codes relating to the regulated action or device
  • B60G2500/04—Indexing codes relating to the regulated action or device using inertia type valves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2800/00—Indexing codes relating to the type of movement or to the condition of the vehicle and to the end result to be achieved by the control action
  • B60G2800/16—Running
  • B60G2800/162—Reducing road induced vibrations

Definitions

• shock absorber design in the past is to provide for adjustable rebound resistance.
• a high degree of adjustability in both compression and extension resistance from the exterior of shock absorbers has been achieved in the dual adjustment through the piston rod of the shock absorber of our co- pending patent application.
• Serial No.07/270,010 filed November 14, 1988.
• we have learned that a high degree of adjustability of the shock absorber is highly effective when the track or road conditions are predictable and when the mechanic making the adjustment is thoroughly familiar with the effects of the adjustment.
• shock absorber can be designed employing inertia responsive valving to provide automatic adjustment, not only in compression but in rebound or extension as well and remarkably improve the overall shock absorber performance.
• inertia responsive valving in the shock absorber is of even more importance in the rebound or extension stroke.
• failure of a suspension system to track dips in the terrain can have greater disturbance to the vehicle stability than encountering a bump.
• the failure to track a dip means that the wheel loses contact with the surface momentarily to be followed by striking the opposite side of the dip.
• the net result us an unnecessarily rough ride and loss of traction. This is accomplished in our invention since the extension stroke inertia valve ride on a light spring which neutralizes the weight of the inertia valve allowing the inertial force to overcome the spring and more longitudinally to open a larger orifice in the extension circuit and thereby make the extension stroke cycle smoother.
• both the compression and rebound inertia responsive characteristic may be adjusted externally since both can be located in the piston assembly with access via the piston rod. In an alternate embodiment of this invention, adjustability is also disclosed.
• Fig. 1 is a longitudinal sectional view of the piston and piston rod assembly of one embodiment of this invention employing a pair of inertial responsive valve members but with no inertia forces acting, e.g. smooth ride;
• Fig. 1A is a longitudinal sectional view similar to Fig. 1 with the shock absorber in a different operational condition, namely with extension inertia force present;
• Fig. IB is a longitudinal sectional view similar to Figs 1 and 1A with compression inertia force present;
• Figs. 2A and B together are an exploded view of an entire shock absorber including the piston and piston rod of the embodiment of Fig. 1;
• Fig. 3 is a simplified elevational view of a wheel- shock absorber combination encountering different types of discontinuities in the surface traveled;
• Fig. 4 is a fragmentary longitudinal sectional view of the piston and piston rod assembly of a second embodiment of this invention with both compression and inertia responsive valves both located in the piston rod;
• Figs. 5 A, B and C are a series of fragmentary longitudinal sectional views of the piston rod-inertial responsive valve combination of Fig. 4 shown in three different operational conditions;
• Fig. 6 is a fragmentary longitudinal sectional view of the piston and piston rod assembly of a third embodiment of this invention with two inertial responsive valve members, both located in the piston;
• Fig. 7 is a fragmentary longitudinal sectional view of the piston and piston rod assembly of a fourth embodiment of this invention, similar to the embodiment of Fig. 6 but with different flow paths on compression and rebound operating strokes; and Fig. 8 is a fragmentary longitudinal sectional view of the piston and piston rod assembly of a fifth embodiment of this invention employing a single inertial responsive valve located in the piston rod.
• a totally self contained automatic terrain condition adjusting shock absorber 10 in Figs. 2A and 2B is shown including a body 11 having an end cap 12 with an end fitting 13 designed to mount on the sprung portion of a vehicle.
• the body 11 has a single tubular wall which defines the shock absorber cylinder. It may be fabricated from aluminum with a hard anodize coating or mild steel and typically will have wall thickness of 0.125 and an overall length, depending upon the application of from 6" to 18" in length.
• the upper end of the tubular portion of the body 11 may be welded or in threaded engagement with the end cap 12.
• the body has an internal end seal (unshown) with a coaxial opening through which a hollow piston rod 14 extends with its end fitting 15 similar to end fitting 13.
• Fitting 15 is designed to be lowermost when mounted on the vehicle and engages an unsprung portion, namely the wheel suspension.
• the upper end region of the piston rod 14 carries a piston 16 of generally recessed disk shape and having an annual recess 20 in which a T seal 21 is supported by a pair or back-up rings 22 and 23.
• the seal 21 provides an effective seal for hydraulic fluid contained within the shock absorber 10 within the upper chamber 24, above the piston 16 and in lower chamber 25 below the piston 16.
• the only flow paths between the chambers 24 and 25 is through the piston assembly 30 which includes the piston rod 15 and piston 16.
• the piston 16 includes a plurality or radially displaced through apertures 31, for example, 8 in number, two of which are shown by dashed lines in Fig. 1.
• the lower side of the apertures 31 are all simultaneously closed by washer shaped check valve 32 which is retained by lower stop 33 a shim washer and spring fastener 34, commonly referred to as a Circlip.
• the apertures 31 allow normal flow from chamber 24 to chamber 25 during compression stroke (upward in the drawing, Fig. 2) movement of the piston 16.
• the piston 16 is secured to the piston rod 15 by threads 40 and clip 41.
• the piston rod 14, as may be seen in Fig. 1, extends through the piston 16 and carries an inertial mass member 42 in slidable engagement with the outer surface of the piston rod 14.
• the mass member 42 is biased outward (upward in the drawing) by captured spring 43 thereby mass member 42 is maintained in near weightlessness when in its closed position and a series of ports 44 open in the wall of the piston rod 14. This allows communication between the chamber 24 and a chamber 25 via channel 45, annular groove 46 in a tubular rod insert 50 within the wall of piston rod 14 and radial ports 51 whenever the mass member 42 is in the position shown in Fig. 1 uncovering ports 44.
• the upper limit of movement of mass member 42 is defined by clip 56 at the outer end of piston rod 14.
• the spring 43 tends to counteract the weight of the mass member 42 so that it responds to abrupt downward movement of the piston 16 and rod 14 to open the ports 44.
• a check valve assembly comprising tubular check valve 52, its bias spring 53, its stop 54 and spring clip retainer 55.
• the spring 53 normally biases the check valve 52 in its closed position as shown in Fig. 1 to be opened only when the pressure within chamber 25 exceeds that of chamber 24, on the extension or rebound stroke with the piston and rod moving downward in the drawing.
• a second check valve in the form of a ball 60 with its bias spring 61 is located within the piston 14 and retained by stop 62.
• This check valve 60 closes port 63 in fluted tubular member 64.
• the flutes of member 64 are in press fit engagement with the inner wall 14i of the piston rod 14 and the space between the flutes allows upward flow of fluid to ports 51 after passing downward through passage 50p of tubular member 50, past check valve 60 by depressing its spring 61, down through passage 65 in the stop 62, through radial ports 66 and ports 70 before beginning reverse flow through the flutes to port 51. This flow occurs on upward normal movement of the piston 16 and rod 14.
• the ports 70 are restricted.
• a second inertial responsive member Located below the check valve 60 and its assembly within the hollow portion of the piston rod 14 is a second inertial responsive member, namely a sleeve valve 80 which is biased against stop 62 by spring 81.
• the spring 81 may have a spring constant greater than is required to merely balance the weight of the sleeve 80 since a "weightless" inertia responsive valve is not as important on the compression stroke as we have found to be needed for the rebound or extension stroke.
• Guide 82 is secured to the bottom of the piston rod 14 recess and is in slip fit relationship with member 80.
• the inertia responsive member 80 Upon rapid compression stroke, the inertia responsive member 80 remains in place in space and the rod 14 moves upward fully opening the communication between passage 65, port 66 and the return flow passages of fluted member 64 to ports 51. This reduces the resistance to compression stroke flow on rapid compression stroke movement.
• the shock absorber of Figs. 1 and 2 is normally installed as shown with the fitting 13 at the top, secured to the body or chassis of the vehicle and the fitting 15 secured as by a through bolt to a portion of the wheel suspension.
• the upper end of the shock absorber is secured to the chassis and the lower end of the shock absorbed is secured via a through bolt to the suspension.
• the upper end of the shock absorber is typically attached to the chassis and the lower end secured to the wheel suspension.
• the mounting in each case is typically the same.
• the upper ends of the two shock absorbers are pivoted from opposite sides of the frame and the lower or piston rod ends are pivoted on the rear suspension swing arm.
• the coil- over-shock embodiment of this invention is preferred.
• the shock absorber reacts like a conventional shock absorber except that due to its simplicity, lack of double walls and relatively massive porting, runs cool and provides a smooth ride.
• the stiff rebound resistance causes the suspension to extend and the rapid rebound or extension opens the rebound bypass path so that the wheel tracks the fading side of the bump without losing ground contact .
• a suspension system employing the shock absorber of this invention can track the more difficult type of terrain anomaly, namely the dip as illustrated in Fig. 3 D.
• a rapid extension is required to follow the terrain.
• a rapid falling away of the road surface has been the nemesis of racing drivers and road drivers, as well, without full recognition of the problem or the needed solution.
• the rebound inertia responsive valve allows the wheel to track the dip and consequently have it in ground contact when it reaches the other side rather than striking the rear face of the dip after having lost road contact.
• the need for rapid compression on reaching the rear face of the dip a accomplished by the inertia responsive compression valve member 80. Therefore the cooperation between the rebound or extension inertia valve to allow tracking of the dip and the rapid release of compression stiffness by the compression inertia responsive valve allows the wheel to fully track both bumps and dips.
• the inertia responsive valves are virtually insensitive to deceleration or lateral accelerations as incurred in rapid braking and abrupt turns. Therefore, the suspension employing this shock absorber does not respond to either of these normal driving maneuvers with any inertia responsive change in characteristics.
• the porting controlled by the inertia responsive valves is radially designed and the valve operators are sleeve like structures of generally equal top and bottom surface areas. They are not pressure responsive to any detectable degree. Therefore, the truly are fully inertia responsive in both modes of shock absorber operation, compression and rebound and insensitive to the various other forces to which the shock absorber and its internal hydraulic fluid are subjected.
• FIG. 4 Such an embodiment is shown in Fig. 4 in which a piston 116 operating within cylinder similar to cylinder 11 of Figs. 1 and 2 and not shown in Fig. 4.
• the piston 116 includes a series of through apertures 120 similar to the corresponding apertures 31 of Fig. 1 as well as a spring washer 121 acting as a check valve blocking flow upward in the drawing, Fig. 4.
• a parallel flow path from upper chamber 24 to lower chamber 25 is included in the annular wall 116A of piston 116 including a check valve 122 with its associated bias spring 123 and stop 124.
• the piston rod 114 is hollow at its upper end with an annular recess 114R in which a pair of coaxial inertial responsive sleeve valve members 125 and 130 are located.
• Valve member 125 the compression stroke responsive member, is secured by clip 126 within the cup shaped recess 131 of the extension stroke inertia responsive valve member 130.
• Valve member 125 is biased upward by spring 127 against retainer ring 132 which acts as a stop for the maximum upward position of compression inertia valve member 125.
• port 133 is aligned with annular extending through port 134 of the rebound inertia valve 130. Therefore, in its normal at rest position as shown in Fig. 4, the compression inertia valve 125 allows restricted flow between chamber 24 and 25 via piston recess 114R, passage 135, port 133 in valve member 125, port 134 and port 170 in piston rod 114.
• Valve 130 includes a plurality of side ports 141 normally aligned with ports 142 in valve member 125.
• FIG. 6 another embodiment of this invention may be seen in which both a compression inertia responsive and a rebound inertia responsive valve may be found, both within the piston 216 with the compression inertia valve 225 acting to control the flow through a port 226 in the piston 216 while rebound inertia responsive valve 230 is located coaxially within the piston 216, encircling the piston rod 214 and controlling the flow through port 234 in the piston rod 214.
• a single check valve 260 with its bias spring 261 and stop 262 prevent compression stroke flow through the piston rod 214.
• Normal extension flow r passes from chamber 25 via port 251 in the piston rod 214, through central passage 265, past open check valve 260, through port 244 in the piston rod 214 through recess 234and into chamber 24.
• Abrupt extension flow This embodiment places both inertia responsive valves 225 and 230 in the same space, the recess in the head of the piston 216 in non interfering positions and both relatively unresponsive to pressure changes within the chamber 24 since they, again control radially extending ports and present virtually identical surface area, top and bottom.
• Fig. 7 we have illustrated a dual compression- extension inertia responsive piston assembly in which the piston 316 is recessed and a rebound inertia responsive valve 330 is slidably mounted in the piston 316and normally biased upward by spring 331 shown in its no inertia force present condition.
• Fig. 8 illustrates, perhaps the simplest, yet the most important feature of this invention in that it provides normal compression responsive operation with inertia responsive rebound or extension operation.
• a relatively simple, inexpensive piston 416 is shown threaded on piston rod 414.
• the piston 416 includes T seal 421 and a plurality, for example, 8, through ports 431 all closed by ring check valve 432 which is spring biased closed by a plurality of helical springs 433 resting on retainer ring 434.
• the check valve 432 allows relatively free compression stroke flow in the direction of the c arrow.
• Fig. 2 shows an entire shock absorber and it is to be recognized that each of the embodiments of these figures will be incorporated in an entire shock absorber in accordance with well known shock absorber manufacturing practices including selecting dimensions, orifice sizes, seals and operating fluids for the particular application.
• the test vehicle was a 1981 Class 10 off road race car Class 10 which is unlimited in suspension and restricted in engine size to 1650cc. Because of the age of the test vehicle, it should not be considered as a front running car because of limited wheel travel (10" travel in front 11" travel in rear) as opposed to current state of the art vehicles have up to 20" travel in front, 24" travel in rear.
• the test vehicle won a 3rd in class and 7th overall using one of these shock absorbers and 2 conventional shock absorbers on each rear wheel. I n the next race, the same vehicle won first in class and 3rd overall this using the same configuration as in the earlier test. At this point, we felt that this reliability of this new design was sufficiently well enough to run with only these shock absorbers, at least in the race.
• the shock absorber of this invention adjusts the dampening characteristics with respect to vehicle inertia not just spring and impact forces as in conventional shock absorbers. This feature allows the vehicle to maintain a very parallel relationship with the terrain with increased control and improved directional stability.
• shock absorbers of this invention resulted in another first place and in the process was much faster than unlimited class cars with 3000cc engine and state of the art suspensions.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fluid-Damping Devices (AREA)

Applications Claiming Priority (1)

Publications (2)

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ID=22225647

Family Applications (1)

Country Status (3)

Families Citing this family (10)

Citations (4)

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• 1991
  • 1991-07-02 EP EP91918233A patent/EP0591205A4/fr not_active Withdrawn
  • 1991-07-02 JP JP3516936A patent/JPH06508671A/ja active Pending
  • 1991-07-02 WO PCT/US1991/004708 patent/WO1993001426A1/fr not_active Application Discontinuation

Patent Citations (4)

Non-Patent Citations (3)

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