Suspension unit for a motor vehicle shock absorber

Claim 2

A suspension unit for a vehicle, having a body structure and wheel supporting means, comprising a cylinder having formed therein a cylinder chamber filled with pressurized fluid, an inlet passageway opening into said cylinder chamber and communicating with a source of pressurized fluid and an outlet passageway opening into said cylinder chamber and communicating with a drain line, a piston axially slidable in said cylinder chamber, a piston rod connected to said piston and extending externally of said cylinder, a free piston axially slidably fitted in said cylinder chamber, between said piston and said inlet and outlet passageways opening into said cylinder chamber, and having formed therein a passageway providing fluid communication therethrough, a first control valve having a valve head for controlling fluid communication between said cylinder chamber and said inlet passageway, said valve head being operable responsive to the axial movement, in one direction, of said free piston to provide said fluid communication between said cylinder chamber and said inlet passageway, a second control valve having a valve head for controlling fluid communication between said cylinder chamber and said outlet passageway, said valve head of said second control valve being operable responsive to the axial movement, in another direction, of said free piston to provide said fluid communication between said cylinder chamber and said outlet passageway, a first detecting member disposed between said free piston and said valve head of said first control valve and operable to detect axial movement of said free piston in excess of a predetermined limit to move said valve head to a position to provide communication between said inlet passageway and said cylinder chamber, a second detecting member disposed between said free piston and said valve head of said second control valve and operable to detect axial movement of said free piston in excess of a predetermined limit to move said valve head to a position to provide communication between said outlet passageway and said cylinder chamber, a first preloaded spring disposed between an end wall of said cylinder chamber and said free piston to bias said free piston toward said piston, and a second preloaded spring disposed between said free piston and said piston to bias said free piston toward the end wall of said cylinder chamber, said first and second preloaded springs cooperating with each other to hold said free piston in a position in which said first and second detecting members are prevented from moving said valve heads of said first and second control valves, respectively.

Claim 3

A suspension unit as claimed in claim 1, further comprising vehicle level adjusting means for adjusting the total length of the suspension unit.

Claim 4

A suspension unit as claimed in claim 2, in which said piston rod has an axial bore open at one end to said cylinder chamber and at the other end communicating with said source of pressurized fluid and in which said vehicle level adjusting means comprise a floating piston axially slidabLe in said bore in the piston rod for defining a control fluid chamber between said floating piston and said other end of said bore, said floating piston receiving at its upper surface said second preloaded spring, and a control fluid regulator valve unit for selectively providing fluid communication between said control fluid chamber and said source of pressurized fluid.

Claim 5

A suspension unit as claimed in claim 1, in which said cylinder further includes a cylinder head having formed therein said inlet and outlet passageways, and in which said cylinder head further includes in said inlet passageway a first chamber communicating with said source of pressurized fluid and a second chamber communicating at one end with said first chamber and at the other end with said cylinder chamber, and a third chamber communicating at one end with a drain line through a first auxiliary passageway having a restriction therein and at the other end with said cylinder chamber and said cylinder head also includes in the outlet passageway a fourth chamber communicating with said drain line and a fifth chamber communicating at one end with said fourth chamber and at the other end with said cylinder chamber and said cylinder head still further includes a second auziliary passage communicating with said cylinder chamber and with said drain line through a passageway with a restrictor provided therein, and further comprising an inlet valve having a valve head situated in said first chamber and a piston having a body portion axially slidable in said first and second chambers and a flange portion provided at one end of said body portion, said valve head mounted on said piston, said body portion of the piston being hermetically and slidably received in the inlet passageway between said first and second chambers thereby to shut off fluid communication therebetween through the inlet passageway, said flange portion of the piston dividing said second chamber into an upper and a lower portions and being hermetically and slidably received in said second chamber thereby to shut off fluid communication between the upper portion and lower portion of said second chamber, said upper portion of the second chamber communicating with said third chamber, said lower portion of the second chamber communicating with said cylinder chamber, said piston having a passage therein providing communication between said first chamber and the lower portion of said second chamber, and a spring seated on said flange portion for urging at all times said inlet valve in the direction of opening said inlet passageway, and in which said first control valve is situated in said third chamber and further including a spring normally urging said first valve to a position to block fluid communication between said third chamber and said cylinder chamber, said first detecting member having a predetermined length and projecting from said valve head into said cylinder chamber to detect the axial movement of said free piston exceeding a predetermined limit thereby to open said first valve, the spring of said inlet valve and the sectional area of said flange portion of the piston of said inlet valve being selected so that when said first control valve is closed to shut off fluid communication between said cylinder chamber and said upper portion of the second chamber the total force caused by the fluid pressure acting on the bottom surface of said flange portion exceeds the total force of said spring of the inlet valve acting on the upper surface of said flange portion thereby to close said inlet valve and when said first control valve is opened to provide fluid communication between said cylinder chamber and said upper portion of said second chamber thereby to apply fluid pressure on the upper surface of said flange portion of said piston of said inlet valve the sum of the total force caused by the fluid pressure and the total force of the spring of the inlet valve acting on the upper surface of said flange portion exceeds the force caused by the fluid prEssure acting on the bottom surface of said flange portion thereby to open said inlet valve, and further comprising an outlet valve having a valve head situated in said fourth chamber and a piston having a body portion axially slidable in said fourth and fifth chambers and a flange portion provided at one end of said body portion, said valve head being seated on said piston, said body portion of the piston being hermetically and slidably received in the outlet passageway between said fourth and fifth chambers thereby to shut off fluid communication therebetween through said outlet passageway, said flange portion of the piston of the outlet valve dividing said fifth chamber into an upper and a lower portions and hermetically and slidably received in said fifth chamber thereby to shut off fluid communication between the upper portion and the lower portion of said fifth chamber directly, said upper portion of the fifth chamber communicating with said second auxiliary passageway between said restrictor of the second auxiliary passageway and said cylinder chamber, said lower portion of the fifth chamber communicating with said cylinder chamber through a passage, said piston of the outlet valve having a passage therein providing communication between said fourth chamber and the lower portion of said fifth chamber, and a spring seated on said flange portion of the piston of said outlet valve for urging at all times said outlet valve in a direction of opening said outlet passageway, and in which said second control valve normally closes said second auxiliary passageway, the spring of said outlet valve and the sectional area of said flange portion of the piston of said outlet valve being selected so that when said second control valve is closed to shut off fluid communication between said cylinder chamber and said upper portion of the fifth chamber the total force caused by the fluid pressure acting on the bottom surface of said flange portion of the piston of said outlet valve exceeds the total force of said spring of the outlet valve acting on the upper surface of said flange portion of the piston of said outlet valve thereby to close said outlet valve and when said second control valve is opened to provide fluid communication between said cylinder chamber and said upper portion of said fifth chamber thereby to apply fluid pressure to the upper surface of said flange portion of said piston of said outlet valve the sum of the total force of the spring of the outlet valve acting on the upper surface of the flange portion of said outlet valve exceeds the total force caused by the fluid pressure acting on the bottom surface of said flange portion of the piston thereby to open said outlet valve.

Claim 6

A suspension unit as claimed in claim 4, in which said second control valve has and a spring urging said second valve at all times in a direction of closing said second auxiliary passage, and in which said second detecting member projects from said valve head toward said free piston and having a detecting head received in a recess formed in said free piston and slidable relative thereto, said recess being provided with an engaging portion for engaging with said detecting member when the axial movement of said free piston exceeds a predetermined limit.

Claim 7

A suspension unit as claimed in claim 4, in which said second auxiliary passageway communicates with said cylinder chamber between said free piston and the piston and includes a sixth chamber for receiving said second control valve, and in which said second valve has a spring for urging said second valve at all time in the direction of closing said second auxiliary passage, said second detecting member projects from said valve head of said second valve into said cylinder chamber between said free piston and the piston, said second detecting member having a predetermined length and detecting the axial movement of said free piston exceeding a predetermined limit to open said second valve thereby to provide communication between said upper portioN of said fifth chamber and the cylinder chamber between the free piston and the piston.

Claim 8

A suspension unit as claimed in claim 1, in which said piston has formed therethrough a restricted passage for providing fluid communication therethrough thereby to damper the impact of bumps transferred to said suspension unit.

Claim 9

A suspension unit as claimed in claim 1, in which said cylinder and said piston rod are connected to said body structure and said wheel supporting means, respectively.

Claim 10

A suspension unit as claimed in claim 1, in which said first control valve includes a spring urging said valve head to a position to block said fluid communication between said inlet passageway and said cylinder chamber and said second control valve includes a spring urging said valve head to a position to block said fluid communication between said outlet passageway and said cylinder chamber, and in which said first detecting member projects from said valve head toward said free piston to engage said free piston moved in excess of said predetermined limit to open said first control valve and said second detecting member projects from said valve head toward said free piston and having a detecting head which is received in a recess fromed in said free piston, said recess having a portion engaging said detecting head of said second detecting member when the axial movement of said free piston exceeds a predetermined limit.

Claim 11

A suspension unit for a vehicle, having a body structure and wheel supporting means, comprising a cylinder having formed therein a cylinder chamber filled with pressurized fluid, an inlet passageway opening into said cylinder chamber and communicating with a source of pressurized fluid and an outlet passageway opening into said cylinder chamber and communicating with a drain line, a piston axially slidable in said cylinder chamber, a piston rod connected to said piston and extending externally of said cylinder, a free piston axially slidably fitted in said cylinder chamber between said piston rod and said inlet and outlet passageways opening into said cylinder chamber and having formed therein a passageway providing fluid communication therethrough, a first control valve having a valve head for controlling fluid communication between said cylinder chamber and said inlet passageway, said valve head being operable responsive to the axial movement, in one direction, of said free piston to provide said fluid communication between said cylinder chamber and said inlet passageway, a second control valve having a valve head for controlling fluid communication between said cylinder chamber and said outlet passageway, said valve head of said second control valve being operable responsive to the axial movement, in another direction, of said free piston to provide said fluid communication between said cylinder chamber and said outlet passageway, a first preloaded spring disposed between an end wall of said cylinder chamber and said free piston to bias said free piston toward said piston, and a second preloaded spring disposed between said free piston and said piston to bias said free piston toward the end wall of said cylinder chamber, said first and second preloaded spring cooperating with each other to hold said free piston in a balanced position, in which said first control valve further includes a detecting member projecting from said valve head and a spring urging said first control valve to a position to block said fluid communication between said cylinder chamber and said inlet passageway, said detecting member extending toward said free piston to detect the axial movement of said free piston in excess of a predetermined limit to actuate said valve head to a position to provide said fluid communication between said cylinder chamber and said inlet passageway, and said second control valve further includes a valve stem projecting from said valve head, a detecting member provided at one end of said valve stem to detect the axial movement of said free piston to actuaTe said valve head to a position to provide said fluid communication between said cylinder chamber and said outlet passageway, and a spring urging said second control valve to a position to block said fluid communication between said cylinder chamber and said outlet passageway, said detecting member of said control valve being received in a recess formed in said free piston, said recess having a portion engaging said detecting member of said second control valve when the axial movement of said free piston exceeds a predetermined limit.

Claim 12

A suspension unit for a vehicle, having a body structure and wheel supporting means, comprising a cylinder having formed therein a cylinder chamber filled with pressurized fluid, an inlet passageway opening into said cylinder chamber and communicating with a source of pressurized fluid and an outlet passageway opening into said cylinder chamber and communicating with a drain line, a piston axially slidable in said cylinder chamber, a piston rod connected to said piston and extending externally of said cylinder, a free piston axially slidably fitted in said cylinder chamber between said piston rod and said inlet and outlet passageways opening into said cylinder chamber and having formed therein a passageway providing fluid communication therethrough, a first control valve having a valve head for controlling fluid communication between said cylinder chamber and said inlet passageway, said valve head being operable responsive to the axial movement, in one direction, of said free piston to provide said fluid communication between said cylinder chamber and said inlet passageway, a second control valve having a valve head for controlling fluid communication between said cylinder chamber and said outlet passageway, said valve head of said second control valve being operable responsive to the axial movement, in another direction, of said free piston to provide said fluid communication between said cylinder chamber and said outlet passageway, a first preloaded spring disposed between an end wall of said cylinder chamber and said free piston to bias said free piston toward said piston, and a second preloaded spring disposed between said free piston and said piston to bias said free piston toward the end wall of said cylinder chamber, said first and second preloaded spring cooperating with each other to hold said free piston in a balanced position, in which said first control valve further includes a detecting member projecting from said valve head and a spring urging said first control valve to a position to block said fluid communication between said cylinder chamber and said inlet passageway, said detecting member extending toward said free piston to detect the axial movement of said free piston in excess of a predetermined limit to actuate said valve head to a position to provide said fluid communication between said cylinder chamber and said inlet passageway, and said second control valve further includes a valve stem projecting from said valve head, a detecting member provided at one end of said valve stem to detect the axial movement of said free piston to actuaTe said valve head to a position to provide said fluid communication between said cylinder chamber and said outlet passageway, and a spring urging said second control valve to a position to block said fluid communication between said cylinder chamber and said outlet passageway, said detecting member of said control valve being received in a recess formed in said free piston, said recess having a portion engaging said detecting member of said second control valve when the axial movement of said free piston exceeds a predetermined limit.