The invention relates to the field of suspension systems for controlling motion. The invention relates to the field of controllable systems for controlling motion and providing support. The invention relates to the field of controllable vehicle systems for controlling vehicle motions. More particularly, the invention relates to vehicle cab suspensions with controllable magneto-rheological fluid device having beneficial motion control.
Magneto-rheological fluid devices such as magneto-rheological fluid dampers and struts are useful in controlling or damping motion in suspension systems such as vehicle suspension systems. A typical magneto-rheological fluid damper includes a damper body with a sliding piston rod received therein. The damper body includes a reservoir that is filled with magneto-rheological fluid, i.e., non-colloidal suspension of micron-sized magnetizable particles. One or more seals are used to retain the magneto-rheological fluid within the reservoir as the piston rod reciprocates within the damper body. The damping characteristics are controlled by applying a magnetic field to the magneto-rheological fluid. A magneto-rheological fluid strut combines a magneto-rheological fluid damper function with the ability to support loads.
There is a need for controllable magneto-rheological fluid devices for supporting a load while providing motion control and vibration isolation. There is a need for vehicle cab magneto-rheological fluid devices for isolating vibrations and cab motions. There is a need for controllable magneto-rheological fluid devices which accurately and economically control and minimize vibrations. There is a need for an economically feasible method of making motion control magneto-rheological fluid devices and vehicle suspension systems. There is a need for a robust suspension system and magneto-rheological fluid devices for isolating troublesome vibrations and controlling vehicle motions. There is a need for an economic suspension system providing beneficial controlled motion and vibration isolation.
In one aspect, a controllable suspension system for controlling the relative motion between a first body and a second body includes at least one strut. The at least one strut includes a magneto-rheological fluid damper which comprises: a damper body; a piston rod guide disposed within the damper body, the piston rod guide having a passage therein for receiving a piston rod; a piston rod bearing assembly disposed in the piston rod guide to engage with and support reciprocal motion of the piston rod; at least a first piston rod seal and at least a second piston rod seal arranged to seal between the piston rod guide and the piston rod; a fluid chamber defined between the piston rod guide and the piston rod; and a piston rod guide gas charged accumulator arranged between the piston rod and the damper body.
In another aspect, a controllable suspension system for controlling the relative motion between a first body and a second body comprises: a damper body; a spring longitudinally aligned with the damper body; a piston rod guide disposed within the damper body, the piston rod guide having a passage therein for receiving a piston rod; a piston rod bearing assembly disposed in the piston rod guide to engage with and support reciprocal motion of the piston rod; at least a first piston rod seal and at least a second piston rod seal arranged to seal between the piston rod guide and the piston rod; a fluid chamber defined between the piston rod guide and the piston rod; and a piston rod guide gas charged accumulator arranged between the piston rod and the damper body.
In another aspect, a controllable suspension system for controlling the relative motion between a first body and a second body includes at least one strut. The at least one strut includes a magneto-rheological fluid damper which comprises: a damper body; a piston rod guide disposed within the damper body, the piston rod guide having a passage therein for receiving a piston rod; a piston rod bearing assembly disposed in the piston rod guide to engage with and support reciprocal motion of the piston rod; at least a first piston rod seal and at least a second piston rod seal arranged to seal between the piston rod guide and the piston rod; a fluid chamber defined between the piston rod guide and the piston rod; means for filtering fluid entering the fluid chamber; and a piston rod guide gas charged accumulator arranged between the piston rod and the damper body.
In another aspect, a method of making a controllable suspension system for controlling the relative motion between a first body and a second body comprises: providing a damper body having a reservoir for containing the magneto-rheological fluid; providing a piston rod; providing a piston rod guide disposed within the damper body, the piston rod guide having a passage therein for receiving the piston rod; providing a piston rod assembly coupled to the piston rod guide and arranged to engage and support reciprocal motion of the piston rod; providing at least a first piston rod seal and at least a piston rod seal arranged to seal between the piston rod guide and the piston rod; providing a fluid chamber defined between the piston rod guide and the piston rod; providing a piston rod guide filter arranged in a communication path between the fluid chamber and the reservoir to filter particulates out of fluid entering the fluid chamber; and providing an accumulator arranged between the piston rod guide and the damper body.
In another aspect, a controllable suspension system for controlling the relative motion between a first body and a second body includes at least one magneto-rheological fluid damper. The at least one magneto-rheological fluid damper comprises: a damper body; a piston rod guide disposed within the damper body, the piston rod guide having a passage therein for receiving a piston rod; a piston rod bearing assembly disposed in the piston rod guide to engage with and support reciprocal motion of the piston rod; at least a first piston rod seal and at least a second piston rod seal arranged to seal between the piston rod guide and the piston rod; and a piston rod guide gas charged accumulator arranged between the piston rod and the damper body. The magneto-rheological fluid damper includes a reservoir for a magneto-rheological fluid provided within the damper body and a piston rod guide filter arranged in a communication path between the fluid chamber and the reservoir to filter particulates out of the magneto-rheological fluid entering the fluid chamber from the reservoir.
In another aspect, a vehicle suspension system for controlling the relative motion between a first body and a second body comprises: a damper body; a spring longitudinally aligned with the damper body; a piston rod guide disposed within the damper body, the piston rod guide having a passage therein for receiving a piston rod; a piston rod bearing assembly disposed in the piston rod guide to engage with and support reciprocal motion of the piston rod; at least a first piston rod seal and at least a second piston rod seal arranged to seal between the piston rod guide and the piston rod; a fluid chamber defined between the piston rod guide and the piston rod; a piston rod guide gas charged accumulator, said piston rod guide gas charged accumulator arranged between the piston rod and the damper body; and a piston rod guide filter.
In another aspect, a method of controlling motion between a first body and a second body comprises: providing a magneto-rheological damper fluid comprised of a plurality of magnetic particulates in a carrier fluid; providing a damper body having a reservoir for containing the magneto-rheological fluid; providing a piston rod; providing a piston rod guide disposed within the damper body, the piston rod guide having a passage therein for receiving the piston rod; providing a piston rod assembly coupled to the piston rod guide and arranged to engage and support reciprocal motion of the piston rod; providing at an outer piston rod seal arranged to seal against the piston rod; providing a piston rod guide accumulator arranged between the piston rod and the damper body; and inhibiting the magnetic particulates from the magneto-rheological fluid in the reservoir from reaching the outer piston rod seal.
The accompanying drawings, described below, illustrate typical embodiments of the invention and are not to be considered limiting of the scope of the invention, for the invention may admit to other equally effective embodiments. The figures are not necessarily to scale, and certain features and certain view of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.
The invention will now be described in detail with reference to a few preferred embodiments, as illustrated in the accompanying drawings. In describing the preferred embodiments, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the invention may be practiced without some or all of these specific details. In other instances, well-known features and/or process steps have not been described in detail so as not to unnecessarily obscure the invention. In addition, like or identical reference numerals are used to identify common or similar elements.
In an embodiment the invention includes a controllable suspension system for controlling the relative motion between a first body and a second body. Referring to
The controllable suspension system 20 includes at least one magneto-rheological fluid strut (30 in
Referring to
The damper piston 42 is supported within the longitudinal damper tubular housing 34 with an upper piston rod bearing assembly 54 disposed between the longitudinal damper tubular housing 34 and the longitudinal piston rod 52. The piston rod bearing assembly 54 has a piston rod bearing seal interface length BL with BL>HL and contact between the piston head 44 and the damper tubular housing inner wall 38 is inhibited. Preferably the bearing assembly 54 has a minimal bearing gap Bgap between the bearings 56 and the OD of the piston rod 52. As shown in
Preferably the piston 42 has a constant bearing length in that the piston head 44 has no substantial bearing contact with the housing inner wall 38, with the cantilevered piston 42 providing a single ended damper 32 as compared to a double-ended damper. Preferably the rod 52 terminates with the piston head 44, with the piston head unconnected to the housing 34 except for the single bearing assembly 54. Preferably the rod 52 and the piston head 44 are unconnected to the lower housing end 58 distal from the piston rod bearing 54 and the upper housing end 60. Preferably the only mechanical connection of the piston head 44 is with the single piston rod 52 extending to the upper bearing assembly 54, with rod 52 terminating with the piston head 44, with no contact of piston head 44 with housing inner side walls 38 or the lower damper end 58 distal from the upper damper end 60 with the bearing 54. In embodiments contact of piston head 44 is inhibited with minimized perimeter occupying axially aligned guides 95. Preferably the piston head 44 is free of internal fluid flow conduits, preferably with substantially all fluid flow between the piston head 44 and housing 34 through the fluid flow gap 50, preferably with the fluid flow gap maintained with assistance of guides 95 which assist in ensuring that substantial contact between the piston head 44, particularly the magnetic poles (96 in
Preferably the magnetorheological fluid damper 32 includes an upper volume compensator 62. The magnetorheological fluid damper volume compensator 62 preferably is proximate the piston rod bearing assembly 54. Preferably the volume compensator 62 is adjacent the upper piston rod bearing 54. Preferably the bearing holder support structure housing 55 and the volume compensator housing are integrated together to provide an upper bearing gas charged compliance member. Preferably the gas compliance volume compensator 62 is in fluid communication with the first upper variable volume magnetorheological fluid chamber 46, with the volume compensator proximate the upper bearings 56 and the piston rod 52, preferably with upper fluid chamber 46 and volume compensator 62 in use in the suspension system 20 oriented on top relative to the force of gravity to allow gas bubble migration into volume compensator 62. Preferably the damper 32 configuration provides for a dry assembly process with the magnetorheological fluid filled into the damper after the piston 42 is assembled into the housing 34, and preferably then gas pressure charging of gas compliance volume compensator 62.
Preferably the strut 30 includes a longitudinal air gas spring 64, with the longitudinal gas spring 64 aligned with the longitudinal damper tubular housing longitudinally extending axis 36. Preferably the strut 30 includes the strut air spring 64 and the magneto-rheological fluid damper 32 aligned with the common center axis 36 and packaged together with the gas spring 64 encompassing the damper 32, with the upper end of the damper including the piston rod 52, substantially housed within the gas spring 64. Preferably the upper end of the strut 30 includes an upper strut end head member 66 (also shown in
Referring again to
Preferably volume compensator 62 is adjacent the upper piston rod bearing assembly 54, preferably with the bearing holder support structure 55 and volume compensator housing cavity 82 integrated to provide an upper damper rod bearing gas charged compliance member. Preferably the rod bearing gas charged compliance member support structure 55 includes a gas compliance charging conduit 90 for filling the cavity 82 with a pressurized gas, preferably after the piston has been assembled into the housing and bearing and the damper has been filled with the magnetorheological fluid. Preferably the volume compensator 62 is in fluid communication with the adjacent damper fluid chamber 46 through a plurality of fluid volume compensating conduits (92 in
Referring to
Referring again to
In a preferred embodiment the suspension system 20 is a cab suspension system with two back cab struts 30 and the front of the vehicle cab is mounted without such controllable cantilevered magnetorheological fluid damper struts 30, such as hard mount or mounted with noncontrolled elastomer mounts. In a preferred cab suspension system 20 embodiment with two rear back cab struts 30 and the front of the vehicle cab is mounted without such controllable cantilevered magnetorheological fluid damper struts 30, the struts 30 are self controlled and autonomous with each having its own circuit board control system, with the strut control system sharing and communicating its sensor data, such as its processed accelerometer information, with each other through the electrical communication connection 78 link to control roll of the cab body. In preferred embodiments the controllable magnetorheological fluid damper struts 30 are self controlled and autonomous with each having its own circuit board control system 72 housed in its upper strut end head member 66, with the struts control system sharing its sensor data through its electrical communication connection 78 to control a motion of the cab relative to the frame, such as to control roll, or with a four point strut suspension controlling roll and pitch of the cab with the four self controlled sensor data sharing struts 30. In a preferred embodiment, as illustrated in
In an embodiment the invention includes a controllable damper for controlling motion. The controllable damper 32 provides for the controlling or relative motion between a first body 22 and a second body 24, preferably with the damper controlling motion in a vehicle, most preferably in a suspension system 20 between a vehicle frame and the vehicles cab. In alternative embodiments the damper 32 provides for controlling motion in non-vehicle stationary suspensions. The controllable damper 32 includes a longitudinal damper tubular housing 34 having a longitudinally extending axis 36. The longitudinal damper tubular housing 34 has an inner wall 38 for containing a magnetorheological fluid 40 within the tubular housing, with the damper housing having an upper damper end 60 and a lower damper end 58. The controllable damper 32 includes a cantilevered single ended damper piston 42. The damper piston 42 includes a piston head 44 movable within the damper tubular housing 34 along a longitudinal stroke length of the tubular housing, with the damper piston head 44 providing a first upper variable volume magnetorheological fluid chamber 46 and a second lower variable volume magnetorheological fluid chamber 48. The damper piston head 44 has a fluid flow gap 50 between the first upper variable volume magnetorheological fluid chamber 46 and the second lower variable volume magnetorheological fluid chamber 48 with a piston head fluid flow interface length HL, preferably with the gap 50 having a width Pgap between the piston head OD and inner surface ID of the tubular housing 34. The damper piston 42 has a longitudinal piston rod 52 for supporting the piston head 44 within the longitudinal damper tubular housing 34. Preferably the cantilevered piston rod 52 is the only mechanical support for supporting the piston head within the damper housing with a bearing. The piston 42 is supported within the longitudinal damper tubular housing with an upper piston rod bearing assembly 54 disposed between the longitudinal damper tubular housing 34 and the longitudinal piston rod 52. The piston rod bearing assembly 54 having a piston rod bearing seal interface length BL, wherein contact between the piston head 44 and the damper tubular housing inner wall 38 is inhibited. Preferably the piston head 44 is a wearbandfree piston head, with the magnetorheological fluid flow gap width Pgap maintained between piston head OD sides and tubular housing inner wall with no wear band or seal on the piston head or between the piston OD sides and the inner wall. Preferably the damper 32 minimizes off state resistance a minimized parasitic drag and resistance. Preferably the off state energy dissipation of damper 32 when no controlling current is supplied to the piston head EM coil 94 is minimized by inhibiting contact between the piston head and housing wall while maintaining the predetermined magnetorheological fluid flow gap cylindrical shell of length HL and thickness Pgap. Preferably the piston 42 has a constant bearing length BL in that the piston head 44 has no bearing contact with the housing inner wall 38. Preferably the damper 32 is a single ended damper as compared to a double ended damper, preferably with the rod 52 terminating with the piston head 44, with the piston head otherwise unconnected to the housing and the lower housing end 58 distal from the piston rod bearing 54, preferably with the only mechanical connection of the piston head 44 with the single piston rod extending to the upper bearing assembly, with the rod terminating in the piston head. Preferably the piston head 44 is free of internal fluid flow conduits inside the piston head OD, preferably with substantially all fluid flow of the magnetorheological fluid 40 between the piston head and the housing through the magnetorheological fluid flow gap 50. Preferably the controllable damper 32 cantilevered piston length BL is greater than the piston head cylindrical shell gap length HL.
Preferably the controllable magnetorheological fluid damper 32 includes an upper damper volume compensator 62. The volume compensator 62 is proximate the piston rod bearing assembly 54. Preferably the gas compliance volume compensator 62 is adjacent the upper piston rod bearing 54, preferably with the bearing holder support structure 55 and the volume compensator housing cavity 82 integrated into an upper bearing gas charged compliance member. Preferably the gas compliance volume compensator 62 is in fluid communication with the first upper variable volume magnetorheological fluid chamber 46, with the volume compensator proximate the upper bearing and the piston rod, preferably with upper fluid chamber 46 and volume compensator 62 in use oriented on top of lower fluid chamber 48 relative to the force of gravity to allow gas bubble migration upward into volume compensator 62. Preferably the damper 32 provides for a dry assembly process with magnetorheological fluid filled after the piston 42 is assembled in the housing 34, preferably through a lower housing end opening 59, then gas pressure charging of the gas compliance volume compensator 62 through an upper end conduit 90. Preferably the piston rod bearing assembly bearing holder support structure 55 includes fluid flow conduits 92 to allow flow of fluid into and out of the volume compensator, preferably with conduits 92 providing for greater flow than the magnetorheological piston head gap 50, preferably with relatively high flow into and out of the volume compensator as compared to piston head flow, with relatively low resistance to flow into volume compensator.
Preferably the controllable magnetorheological fluid damper 32 includes an upper strut end head member 66 with an electrical power input 68. Preferably the upper strut end head member houses the damper control system 72 with electronic control circuit board 74. In a preferred embodiment the power input is included with a multiple wire array connector 78, such as a CAN bus electrical connector 78, preferably with the multiple wire electrical connection providing for receiving outside the strut damper control signals in addition to electrical power input that generates the magnetorheological fluid controllable magnetic field. Preferably the upper strut end head member houses the damper control sensor system, preferably including the upper head end of the magnetostrictive longitudinal sensor 80 that is aligned axis 36 and housed within the piston rod 52. Preferably the upper strut end head member housing includes the control system for also controlling leveling with the gas spring with a leveling valve 76 for controlling pneumatic leveling of the strut 30. Preferably the strut and damper with the upper strut end head member 66 is an intelligent self-contained damper system with the head member containing the electronics control system circuit boards 74 that receives sensor inputs such as from the magnetostrictive sensor 80 and accelerometers 120, and controls the electrical current supplied to the piston head EM coil 94 through the current supply wire circuit 100 to control the damper 32, preferably with the control electronics including accelerometer sensors 120, preferably an at least one accelerometer axis acceleration sensed, preferably with a first accelerometer axis 122 aligned with the damper axis 36 (shown in
Preferably the controllable magnetorheological fluid damper upper piston rod bearing assembly 54 includes a bearing holder support structure 55 which receives a first upper bearing 56, a distal second lower bearing 56, and a piston rod seal 53 to provide the piston rod bearing seal interface length BL. Preferably the controllable magnetorheological fluid damper upper piston rod bearing assembly 54 includes bearing holder 55 which receives at least first bearing 56 and a compliance member cavity 82 for receiving a volume compensator gas compliance member 84. Preferably the controllable magnetorheologicai fluid damper upper piston rod bearing assembly 54 includes bearing holder 55 which receives at least first bearing 56 and a sensor target magnet holder 86 which receives a target magnet 88 for producing a sensor signal in the proximate magnetostrictive sensor 80 in the non-magnetic piston rod 52, to provide a sensed measurement of the location of the target magnet along the length of sensor 80 to provide a measurement of the stroke position of the piston head in the damper housing that is used as an input into the damper electronic control system.
Preferably the controllable magnetorheological fluid damper piston head 42 includes an insulating encapsulant injected pressurized polymer overmolded electromagnetic coil 94, with the piston head, overmolded electromagnetic coil and magnetic poles ODs sized to provide the predetermined gap Pgap with the housing inner wall ID, with the gap 50 maintained to inhibit contact with the wall 38 and to provide the fluid flow gap with the coil 94 producing a magnetic field for controlling magnetorheological fluid flow through the gap. The controllable piston head electromagnetic coil 94, upper and lower magnetic poles 96 with a variable applied current producing a controlling magnetic field for controlling the flow of magnetorheological fluid 40 between the upper and lower chambers 46 and 48, with the electromagnetic coil 94 comprised of an electrically insulated injected pressurized polymer overmolded electromagnetic magnetorheological fluid coil 94. The preferred modular component injected pressurized polymer overmolded electromagnetic magnetorheological fluid coil 94 is shown in
In an embodiment the invention includes a method of making a controllable suspension system for controlling the relative motion between a first body and a second body. Preferably the invention provides a method of making a controllable vehicle suspension system for controlling the relative motion between a first vehicle body and a second vehicle body, most preferably a method of making a vehicle cab suspensions for controlling the motion between a first body cab 22 and a second body frame 24. The method includes providing the longitudinal damper tubular housing having a longitudinally extending axis, the longitudinal damper tubular housing 34 having inner wall 38 for containing a magnetorheological fluid within the tubular housing. The provided longitudinal damper tubular housing 34 has a first upper end 60 and a second distal lower end 58, with the housing centered about axis 36. The method includes providing piston rod bearing assembly 54 having piston rod bearing seal interface length BL for supporting damper piston 42 within the longitudinal damper tubular housing 34. The method includes providing cantilevered damper piston 42 including piston head 44 and longitudinal piston rod 52. Cantilever piston rod 52 supports the piston head 44 within the longitudinal damper tubular housing, with the upper piston rod bearing assembly 54 disposed between the longitudinal damper tubular housing and the longitudinal piston rod. The method includes disposing the piston rod bearing assembly 54 in the longitudinal damper tubular housing 34 proximate the first upper end 60. The method includes receiving the damper piston longitudinal piston rod 53 in the piston rod bearing assembly 54, wherein the piston head 44 is movable within the damper tubular housing along the longitudinal length of the tubular housing, with the damper piston head providing a first upper variable volume magnetorheological fluid chamber 46 and a second lower variable volume magnetorheological fluid chamber 48, the damper piston head having a fluid flow gap 50 between the first upper variable volume magnetorheological fluid chamber and the second lower variable volume magnetorheological fluid chamber with a piston head fluid flow interface length HL with contact between the piston head and the damper tubular housing inner wall inhibited. The method includes providing magnetorheological damper fluid 40 and disposing the magnetorheological damper fluid 40 in the damper tubular housing 34. The damper provides for controlling the relative motion between the first body 22 and the second body 24. Preferably the method includes providing the longitudinal air strut gas spring 64, and aligning the longitudinal strut gas spring with the longitudinal damper tubular housing longitudinally extending axis 36 with the strut air spring and magnetorheological damper aligned and packaged together with the gas spring encompassing the magnetorheological damper, preferably with the upper end 60 and the piston rod 52 substantially housed within the gas spring 64, preferably with the upper end of strut including the upper strut end head member 66 for attachment to the uppermost first or second body. Preferably the upper strut end head member 66 includes the electrical power input and the compressed air gas input, along with the strut control system with electronic control circuit boards 74, gas spring air sleeve leveling valve 76. In preferred embodiments the upper strut end head member 66 includes the CAN-Bus electrical connection for receiving outside the strut control signals in addition to electrical power input into the strut. In preferred embodiments the upper strut end head member 66 includes the damper sensor system with the end of magneto-strictive longitudinal sensor 80 that is aligned and housed within the piston rod. Preferably the piston rod bearing assembly 54 is provided with the piston rod bearing seal interface length BL greater than the HL. Preferably the upper volume compensator 62 is provided and disposed proximate the piston rod bearing assembly 54. Preferably the upper piston rod bearing assembly includes the bearing holder which receives the first upper bearing and the distal second lower bearing to provide the piston rod bearing seal interface length BL. Preferably the upper piston rod bearing assembly includes the bearing holder which receives the at least first bearing and includes the compliance member cavity for receiving the volume compensator gas compliance member. Preferably the upper piston rod bearing assembly includes the bearing holder which receives the at least first bearing and has the sensor target magnet holder which receives the target magnet for the magnetostrictive sensor in the non-magnetic piston rod. Preferably the magnetorheological fluid damper includes the upper volume compensator, with the volume compensator proximate the piston rod bearing. Preferably at least a first cantilevered magnetorheological fluid damper, and at least a second cantilevered magnetorheological fluid damper are disposed between the first body and the second body. Preferably the at least a third cantilevered magnetorheological fluid damper is disposed between the first body and the second body.
Preferably the invention includes the method of making the controllable damper for controlling motion. Preferably the method includes providing the longitudinal damper tubular housing having the longitudinally extending axis, the longitudinal damper tubular housing having the inner wall for containing the magnetorheological fluid within the tubular housing, the longitudinal damper tubular housing having the first upper end and the second distal lower end. The method includes providing the piston rod bearing assembly, the piston rod bearing assembly having the piston rod bearing seal interface length BL for supporting the damper piston within the longitudinal damper tubular housing. The method includes providing the cantilevered damper piston, the damper piston including the piston head and the longitudinal piston rod for supporting the piston head within the longitudinal damper tubular housing. The method includes disposing the piston rod bearing assembly in the longitudinal damper tubular housing proximate the first upper end. The method includes receiving the damper piston longitudinal piston rod in the piston rod bearing assembly, wherein the piston head is movable within the damper tubular housing along the longitudinal length of the tubular housing, with the damper piston head providing the first upper variable volume magnetorheological fluid chamber and the second lower variable volume magnetorheological fluid chamber, the damper piston head having the fluid flow gap between the first upper variable volume magnetorheological fluid chamber and the second lower variable volume magnetorheological fluid chamber with the piston head fluid flow interface length HL, with HL<BL and contact between the piston head and the damper tubular housing inner wall inhibited. Preferably the method includes providing the upper volume compensator, and disposing the volume compensator proximate the piston rod bearing assembly. Preferably the method includes providing the upper strut end head member with the electrical power input and disposing the strut end head member proximate the damper tubular housing first end. Preferably the method includes providing the upper piston rod bearing assembly with the bearing holder support structure which receives the first upper bearing and the distal second lower bearing to provide the piston rod bearing seal interface length BL. Preferably the method includes providing the upper piston rod bearing assembly with the bearing holder support structure which receives at least the first bearing and includes the compliance member cavity for receiving the volume compensator gas compliance member. Preferably the method includes providing the upper piston rod bearing assembly with the bearing holder support structure which receives at least the first bearing and includes the sensor target magnet holder which receives the target magnet. Preferably the method includes providing the piston head with the injected pressurized polymer overmolded electromagnetic coil.
In an embodiment the invention includes a method of making a controllable damper for controlling motion. The method includes providing a longitudinal damper tubular housing 34 having a longitudinally extending axis 36. The provided longitudinal damper tubular housing 34 has an inner wall 38 for containing a magnetorheological fluid 40 within the tubular housing. The longitudinal damper tubular housing 34 has a first upper end 60 and a second distal lower end 58. The method includes providing a piston rod bearing assembly 54, the piston rod bearing assembly having a piston rod bearing seal interface length BL for supporting a damper piston 42 within the longitudinal damper tubular housing 34. The method includes providing a damper piston 42, the damper piston including a magnetorheological fluid piston head 44 and a longitudinal piston rod 52 for supporting the piston head within the longitudinal damper tubular housing 34. The magnetorheological fluid piston head 44 includes an insulating injected pressurized polymer overmolded electromagnetic magnetorheological fluid coil 94. The controllable magnetorheological fluid damper piston insulating encapsulant injected pressurized polymer overmolded electromagnetic coil 94 and magnetic poles 96 preferably having ODs sized to provide the predetermined gap 50 Pgap with the housing inner wall ID, with the gap 50 maintained to inhibit contact with the wall 38 and to provide the fluid flow gap 50 with the coil 94 producing a magnetic field for controlling magnetorheological fluid flow through the gap. The controllable piston head electromagnetic coil 94, upper and lower magnetic poles 96 with a variable applied current producing a controlling magnetic field for controlling the flow of magnetorheological fluid 40 between the upper and lower chambers 46 and 48, with the electromagnetic coil 94 comprised of the modular component electrically insulated injected pressurized polymer overmolded electromagnetic magnetorheological fluid coil 94. The preferred modular component injected pressurized polymer overmolded electromagnetic magnetorheological fluid coil 94 is shown in
Preferably the received core member 114 includes an inner core center chamber 118 centered inside the core and extending pole member OD, the inner core center chamber 118 receiving the lower piston rod end and preferably the overmolded coil wire pin connectors 108, preferably with the sealing member 98 between the lower rod end and overmolded coil 94, preferably with the inner core center chamber and the lower piston rod end having mating attachment means, preferably such as matching threads for attaching the piston rod 52 with the piston head 44. Preferably the overmolded EM coil 94 includes a longitudinal center axis hub member 124 with the EM coil wire pins 108 and a radially extending wire coil connecting arm structure spokes (126 in
The magneto-rheological fluid damper 200 includes a damper body 202. In this example, the damper body 202 is made of several parts, including a cylinder part 202a and end caps 202b, 202c. However, these parts may be integrated to form a unitary body in alternate embodiments. The end caps 202b, 202c are coupled to distal ends of the cylinder part 202a. The cylinder part 202a is preferably a hydraulic cylinder. The cylinder part 202a contains a reservoir of magneto-rheological fluid (not shown) and a piston (not shown). The piston is coupled to a piston rod 214, which extends through the end cap 202b. The piston rod 214 extends through the end cap 202b and includes a rod end 203 for coupling to a frame or other devices.
In
Referring to
The annular body 210 includes an inner annular recess 218 circumscribing the passage 212 for receiving the piston rod 214. A filtering media 220, which may be annular in shape, is disposed within the annular recess 218. The magnetic field generator 217 described above may be included in the filtering media 220, for example, arranged in a pocket or otherwise supported on or in the filtering media 220. In one example, the filtering media 220 is made of a porous non-magnetic, corrosion-resistant material. In one example, the porous filtering media 220 has pore size less than or equal to 250 nm. In one example, the porous filtering media 220 is made of porous stainless steel having pore size less than or equal to 250 nm. The filtering media 220 includes a pocket 222 inside of which is disposed an inner piston rod seal 224. The annular body 210 includes a pocket 226 inside of which is disposed an outer piston rod seal 228. The inner and outer piston rod seals 224, 228 are arranged to engage the wall of the piston rod 214, thereby forming inner and outer seals between the piston rod guide 206 (or annular body 210) and the piston rod 214. The seals 224, 228 may be made of suitable sealing materials such as elastomeric materials.
The filtering media 220 may include a pocket 230 for receiving a piston rod bearing assembly 232. When the piston rod 214 is received in the passage 212, the piston rod bearing 232 is arranged between the piston rod 214 and the filtering media 220. Further, the piston rod bearing 232 engages with and supports reciprocal motion of the piston rod 214. Any suitable piston rod bearing 232 capable of supporting reciprocal motion of the piston rod 214 may be used. For example, Glacier Garlock DU or DP-4 bearings, available from AHR International, may be used. These bearings offer a smooth low friction bearing surface and are self-lubricating. The permanent magnet 217 or other suitable magnetic field generating component may be placed above the piston rod bearing 232, as shown in
A fluid chamber 234 is formed between the filtering media 220, the inner piston rod seal 224, the piston rod bearing 232, and the piston rod 214. The fluid chamber 234 is in communication with the reservoir 208 containing the magneto-rheological fluid. Preferably in operation, magneto-rheological fluid enters the inner annular recess 218 through ports 236 in the base of the piston rod guide 106 and flows through the filtering media 220 into the filtered fluid chamber 234. That is, the filtering media 220 is disposed in a communication path between the reservoir 108 and the fluid chamber 234. The filtering media 220 strains or filters out the magnetizable particles in the magneto-rheological fluid and allows the filtered carrier fluid to enter the fluid chamber 234. In a preferred embodiment, the permanent magnet 217 is mounted at an end of the filtering media 220 to collect magnetic particle dust left unfiltered by the filtering media 220, preferably providing magnetic filtering of magnetic particles thereby ensuring that the outer piston rod seal 228 is exposed to only filtered non-particulate clear carrier fluid. Protecting the outer seal 228 from particulates prolongs the useful life of the seal. In a preferred embodiment, the filtering media 220 inhibits the migration of magnetic particles from the inner piston rod seal 224 to the outer seal 228, with the outer seal filtered non-particulate clear carrier fluid having less than one percent of the magnetizable (iron) particle fraction of the magneto-rheological fluid contacting the inner piston rod seal 224. The filtering media 220 preferably provides a static charge pressure between the two seals 224, 228, and preferably provides that the inner seal 224 is only exposed to fluid dynamic pressure and that the outer seal 228 is only exposed to static pressure. By exposing the outer seal 228 to only static fluid pressure, air ingestion into the reservoir 108 is prevented.
The annular body 210 of the piston rod guide 206 further includes an outer annular recess 238. A diaphragm or bladder 240 is mounted in the outer annular recess 238 and abuts an inner wall 242 of the damper body 202 of the damper body 202. The diaphragm 240 defines an air-volume which functions as an accumulator 242. In use, the accumulator 244 is charged with an inert gas such as nitrogen. Although not shown, a port may be provided in the inner wall 242 of the damper body 202 or in the annular body 210 through which gas can be supplied into the accumulator 244. The diaphragm 240 is exposed to the magneto-rheological fluid in the reservoir 208 through a gap between the annular body 210 of the piston rod guide 206 and the inner wall 242 of the damper body 202. The accumulator 242 serves to minimize pressure transients in the magneto-rheological fluid in the reservoir 208, thereby minimizing the risk of cavitation or negative pressure. Thus, the accumulator 244 minimizes pressure transients while the porous filter media 220 filters out pressure transients from the outer piston rod seal 228. The combined effect is low charge pressures, e.g., on the order of 200 to 300 psig, without risk of air ingestion and with minimal risk of cavitation. Preferably the piston rod guide 206 includes and houses an accumulator, preferably a gas charged accumulator.
It will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from the spirit and scope of the invention. Thus, it is intended that the invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. It is intended that the scope of differing terms or phrases in the claims may be fulfilled by the same or different structure(s) or step(s).
This application is a continuation-in-part of application Ser. No. 11/742,911, filed May 1, 2007, which claims the benefit of U.S. Provisional Application No. 60/796,567, filed May 1, 2006, all of which the benefit are claimed and are herein incorporated by reference. This application is a continuation-in-part of International Application No. PCT/US07/83937, filed Nov. 7, 2007, which claims the benefit of U.S. Provisional Application No. 60/984,212, filed Oct. 31, 2007, and application Ser. No. 11/742,911, filed May 1, 2007, all of which the benefit are claimed and are herein incorporated by reference.
Number | Date | Country | |
---|---|---|---|
60796567 | May 2006 | US | |
60984212 | Oct 2007 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 11742911 | May 2007 | US |
Child | 12610690 | US | |
Parent | PCT/US07/83937 | Nov 2007 | US |
Child | 11742911 | US |