A monotube damper assembly includes a housing presenting a wall extending between a rod end and a closed end to define a main chamber. A gas cup having a top portion and a body portion is disposed in the main chamber to divide the main chamber of the housing into a gas chamber and a fluid chamber. The gas cup includes a top portion and a body portion. A piston is disposed in the fluid chamber. A rod guide is disposed adjacent to the rod end and spaced part from the piston. A piston rod is connected to the piston. A gas damper having a cylindrical shape includes a restrictor disposed the body portion of gas cup and the top potion of the gas cup for providing additional damping force to the gas cup.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a monotube damper assembly for use in a vehicle.

2. Description of the Prior Art

Monotube damper assemblies are well known in the prior art. The U.S. Pat. No. 8,240,642 to Hamberg et al. discloses a monotube damper assembly including a housing defining a main chamber extending along a center axis between a rod end and a closed end. A gas cup is disposed in the main chamber and is slidable along the center axis to divide the main chamber into a gas chamber extending between the closed end and the gas cup for containing a high pressured gas and a fluid chamber extending between the gas cup and the rod end. A piston is disposed in the fluid chamber and is axially slidable along the center axis. A piston rod is connected to the piston and extends through the rod end. The gas cup includes a top portion and a body portion extending from the top portion and about the center axis.

SUMMARY OF THE INVENTION

The present invention provides for such monotube damper assembly for use in a vehicle including a gas damper having a restrictor disposed in the gas chamber dividing the gas chamber into an upper chamber and a lower chamber for providing additional damping force to the gas cup by limiting flow of the high pressured gas between the upper chamber and the lower chamber in response to a sliding movement of the gas cup.

The present invention improves monotube damper assembly performance by providing an additional damping force to the gas cup of the monotube damper assembly. In addition, the present invention provides for an additional dynamic pressure to the gas cup at higher velocities which results in the onset of lag happening at the higher velocity. As a result, a maximum damping can be tuned at a desired velocity for the monotube damper assembly.

DESCRIPTION OF THE ENABLING EMBODIMENT

Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a monotube damper assembly for use in a vehicle constructed in accordance with the subject invention is shown inFIG. 1.

The assembly20, as generally shown inFIG. 2, includes a housing22, as generally indicated, presenting a wall24having a tubular shape disposed annularly about a center axis A and extending between a rod end26and a closed end28to define a main chamber30,32,34. An end cap36is disposed over the closed end28and presents a first mounting ring38for attaching the housing22to the vehicle.

A gas cup40, as generally indicated, is disposed in the main chamber30,32,34adjacent to the end cap36and is slidable along the center axis A to divide the main chamber30,32,34of the housing22into a gas chamber32,34extending between the closed end28and the gas cup40for containing a high pressured gas and a fluid chamber30extending between the gas cup40and the rod end26for containing a magneto rheological fluid having a predetermined viscosity. In other words, the main chamber30,32,34is separated into the gas chamber32,34and the fluid chamber30by the gas cup40wherein the gas chamber32,34contains the high pressured gas and extends between the closed end28and the gas cup40and the fluid chamber30contains the magneto rheological fluid and extends between the gas cup40and the rod end26. Alternatively, instead of containing a magneto rheological fluid, the fluid chamber30may contain a damping fluid such as a hydraulic fluid.

The gas cup40includes a top portion42having a circular shape and a body portion44having a cylindrical shape extending annularly about the center axis A from the top portion42. The top portion42of the gas cup40presents a pair of protrusions46extending axially from the top portion42and disposed diametrically from one another across the center axis A. The body portion44of the gas cup40defines a seal groove48and a body groove50extending annularly about the center axis A and spaced from one another axially along the body portion44. A gas seal52is disposed in the seal groove48extending annularly about the body portion44of the gas cup40and in sealing engagement with the wall24of the housing22for sealing the gas chamber32,34.

A piston54, as generally indicated, having a cylindrical shape is disposed in the fluid chamber30of the housing22spaced from the gas cup40and is axially slidable along the center axis A. The piston54includes a core unit56having a cylindrical shape defining an outer surface58extending annularly about the center axis A and a core top60presenting a depression62having a cylindrical shape extending along the center axis A. The core unit56also includes a core bottom64presenting a cavity66having a cylindrical shape extending along the center axis A. The outer surface58of the core unit56presents a plurality of core grooves68extending annularly about the center axis A between the core top60and the core bottom64of the core unit56. The core unit56defines a core unit channel70extending along the center axis A and in fluid communication with the depression62and the cavity66.

The core bottom64of the core unit56defines a primary channel72,74having a L-shape in fluid communication between the cavity66and the core grooves68. The primary channel72,74includes a first passage72extending radially outwardly from the cavity66and perpendicular to the center axis A to establish fluid communication with the outer surface58of the core unit56. The primary channel72,74includes a second passage74extending along the outer surface58of the core unit56parallel to the center axis A to establish fluid communication with the core grooves68.

A stopper76is slidably disposed in the cavity66and extends along the center axis A for closing the core unit channel70. A stopper seal78is disposed annularly about the stopper76and engages the stopper76and the core unit56for securing the stopper76in the cavity66of the core unit56. A plurality of coils80are disposed in the core groove68of the core unit56and extends annularly about the core unit56and the center axis A for providing a magnetic field to change the predetermined viscosity of the magneto rheological fluid.

An upper plate82having a circular shape is disposed concentrically to the core unit56and abuts the core top60of the core unit56. The upper plate82presents an upper plate mounting aperture84extending through the upper plate82and disposed on the center axis A. The upper plate82presents a plurality of upper plate apertures86extending through the upper plate82disposed about the upper plate mounting aperture84. A lower plate88having a circular shape is disposed concentrically to the core unit56and abutting the core bottom64of the core unit56. The lower plate88presents a plurality of lower plate apertures90extending through the lower plate88and disposed about the center axis A.

A flux ring92having a cylindrical shape is disposed about and spaced from the core unit56to define a fluid channel94extending between the flux ring92and the outer surface58of the core unit56in fluid communication with the upper plate apertures86and the lower plate apertures90for allowing the magneto rheological fluid to flow through the piston54. The flux ring92presents a plurality of flux ring recesses96extending annularly about the center axis A and spaced axially from one another in the flux ring92for receiving the upper plate82of the piston54and the lower plate88of the piston54. Alternatively, the piston54may include a core unit56having a core top60and a core bottom64defining at least one fluid channel94extending from the core top60to the core bottom64of the core unit56.

A rod guide98, as generally indicated, having a cylindrical shape is disposed concentrically on the center axis A in the fluid chamber30and engages the housing22adjacent to the rod end26and spaced part from the piston54. The rod guide98defines a central bore100,102having a cylindrical shape presenting a groove section100and a pit section102extending along the center axis A. A piston rod seal104is disposed in the groove section100of the central bore100,102extending annularly about the center axis A. The rod guide98defines a plurality of rod guide grooves106extending annularly about the rod guide98and the center axis A. A rod guide seal108extends annularly about the rod guide98in each of the rod guide grooves106and engaging the wall24of the housing22for sealing the fluid chamber30.

A piston rod110extends between a mating end112and a mounting end114along the center axis A and is connected to the depression62of the core unit56of the piston54at the mating end112of the piston54. The piston rod110extends through the upper plate82the pit section102of the rod guide98and slidably engages the piston rod seal104to interconnect the core unit56with the upper plate82and the rod guide98. In other words, the piston54extends through the pit section102of the rod guide98and connects with the core unit56of the piston54for allowing the piston54to slide along the center axis A between the gas cup40and the rod guide98. The piston rod110defines a plurality of retainer grooves116extending annularly about the piston rod110adjacent to the mating end112and spaced axially apart from one another. A retainer ring118is disposed in each of the retainer grooves116and engages the core unit56and the upper plate82for securing the core unit56and the upper plate82to the piston rod110. A second mounting ring120is disposed on the mounting end114of the piston rod110for attaching the piston rod110to the vehicle.

The piston rod110defines a piston rod channel122extending through the piston rod110on the center axis A. A plurality of wires124are disposed in the piston rod channel122and extend through the core unit channel70and the primary channel72,74and electrically connected to the coils80for providing power to the coils80.

A gas damper126having a cylindrical shape includes a restrictor disposed spaced axially between the body portion44of gas cup40and the top potion of the gas cup40and dividing the gas chamber32,34into an upper chamber32extending between the top portion42of the gas cup40and the gas damper126and a lower chamber34extending between the gas damper126and the closed end28for providing additional damping force to the gas cup40by limiting flow of the high pressured gas between the upper chamber32and the lower chamber34in response to a sliding movement of the gas cup40.

The restrictor of the gas damper126presents an orifice128disposed on the gas damper126extending along the center axis A and in fluid communication with the upper chamber32and the lower chamber34for limiting flow of the high pressured gas between the upper chamber32and the lower chamber34disposed in the gas chamber32,34to provide the additional damping force to the gas cup40. In other words, during the sliding movement of the gas cup40the orifice128limits amount of the high pressured gas that can flow from the upper chamber32to the lower chamber34. By limiting the amount of the high pressured gas that can flow from the upper chamber32to the lower chamber34the additional damping force is provided to the gas cup40. The gas damper126includes a projection130extending radially outwardly from the center axis A disposed adjacent to the body portion44of the gas cup40for preventing the gas damper126disposed in the body portion44from engaging the top portion42of the gas cup40. A damper seal132is disposed between the body portion44and the gas damper126for securing the gas damper126in the body portion44of the gas cup40.

In an alternative embodiment of the present invention shown inFIG. 3, instead of having an orifice128, the restrictor of the gas damper126includes a first check valve134extending through the gas damper126parallel to the center axis A for allowing the high pressured gas in the gas chamber32,34to flow unidirectionally through the gas damper126from the lower chamber34to the upper chamber32. The gas damper126includes a second check valve136extending through the gas damper126parallel to the center axis A for allowing the high pressured gas in the gas chamber32,34to flow unidirectionally through the gas damper126from the upper chamber32to the lower chamber34.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims. The use of the word “said” in the apparatus claims refers to an antecedent that is a positive recitation meant to be included in the coverage of the claims whereas the word “the” precedes a word not meant to be included in the coverage of the claims. In addition, the reference numerals in the claims are merely for convenience and are not to be read in any way as limiting.