Patent Description:
Conventional piston dampers include dampers having a tube, a piston assembly (such as a piston assembly including a piston core and a piston ring positioned outward of the piston core to define a through passageway between the piston core and the piston ring), and a piston rod. The tube contains a damping fluid. The piston assembly slidably engages the tube between the closed and open end portions of the tube. The piston rod has a first end portion attached to the piston assembly and a second end portion extending outside the open end portion of the tube. A rod guide assembly is attached to the open end portion of the tube to guide the piston rod and to seal the damping fluid within the tube. A floating, hermetically-sealing gas cup (such as one made of impermeable aluminum) slidingly engages the tube to separate the damping fluid from a gas and slides (floats) to adjust for the volume change caused by the moving piston rod, thermal expansion of the damping fluid, and normal loss of damping fluid, as is known to those skilled in the art. The gas cup has a single seal disposed in fully-circumferential surface groove on the outwardly-facing circumferential surface of the gas cup.

One such a gas cup assembly is disclosed in <CIT>. The gas cup assembly includes a body having an upper surface, a lower surface, an exterior surface and an interior surface. The body defines an aperture extending through the upper surface and the lower surface of the body. A decoupler, made entirely from an elastomeric material, is located in the aperture and secured to the interior surface of the body. However, these designs tend to have durability issues caused by long-term gas leakage through large elastomeric area of the decoupler and gas permeability characteristics of the elastomeric material. Document <CIT> discloses a hydraulic single-tube vibration damper for motor vehicles with a damper cylinder which contains damping fluid and in which there slides a damping piston which is connected to a piston rod and is provided with pressure-dependent valves. Provided at that end of the damper cylinder which is located opposite the piston-rod outlet is a displaceably arranged separating piston which divides the gas-filled compensation space from the working space in a sealing manner and comprises a dimensionally stable piston part guided on the cylinder wall, and an elastic sealing part which seals the compensation space. According to the invention, the piston part and the sealing part are formed from a single component. In addition to simple mounting in the damping cylinder of the separating piston comprising a single component, the invention also permits the use of a wide variety of different forms of sealing parts. Document <CIT> discloses a sealing floating piston, in which a sealing ring extends around the outer circumference of a closed, cylindrical, rigid body, wherein the body is formed by a rigid ring, the inner cross-section of which is closed by a flexible closing element is kept locked. Document <CIT> discloses an air suspension assembly comprising: a top disposed on a center axis, a piston disposed on said center axis spaced from said top, a bellows of an elastomeric material extending about said center axis between a first end secured to said top and a second end secured to said piston connecting said top and said piston defining a first chamber extending between said top and said piston and said bellows, said piston including an upper portion defining a bore disposed on said center axis extending in gas communication with said first chamber, said piston further including a body extending outwardly from said upper portion and about said center axis to a proximal end defining a second chamber extending between said body and said upper portion, a decoupler disposed in said bore of said upper portion attached to said piston and disposed in gas communication with said first chamber and said second chamber. Said decoupler includes a partition member extending transversely across said decoupler isolating said first chamber from said second chamber and defining a first volume for said first chamber between said partition member and said top and said piston and said bellows and a second volume for said second chamber between said partition member and said body for changing pressure in said first chamber and said second chamber by varying said first volume and said second volume in response to a pressure applied to the air suspension assembly.

The present invention in its broadest aspect provides a gas cup which significantly reduces gas pressure loss over time. The present invention also provides a gas cup having variable tuning parameters, which improves the damping characteristics of a damper assembly and thereby improving the ride comfort of a user. The present invention also a gas cup including a decoupler having improved durability thereby increasing the operational life of the damper assembly. The present invention provides a damper assembly including the gas cup that improves ride comfort of a user, especially at high frequency inputs and small amplitude.

It is one aspect of the present invention to provide a gas cup for a damper assembly. The gas cup comprises a body including an upper surface, a lower surface, an exterior surface and an interior surface. The body defines an aperture extending through the upper surface and the lower surface. A decoupler is located in the aperture and secured to the body. A bridging member is located between the decoupler and the body and coupled to the decoupler and the body. The decoupler and the bridging member are made from materials having different elasticity to allow the decoupler to move in the aperture in response to a volumetric change in the damper assembly and to provide variable tuning of the damper assembly. The gas cup further includes at least one stopper located in said aperture and coupled to said interior surface for restricting movement of said decoupler, wherein said at least one stopper includes an upper stopper and a lower stopper, said upper stopper being located adjacent to said upper surface and coupled to said body for restricting an axial movement of said decoupler toward said upper surface, and said lower stopper being located adjacent to said lower surface and coupled to said body for restricting an axial movement of said decoupler toward said lower surface, wherein said upper stopper defines a first orifice bounded by a first periphery, said first periphery extends about a center axis and includes at least one first peak and at least one first trough.

It is another aspect of the present invention to provide a damper assembly. The damper assembly comprises a housing extending along a center axis between an opened end and a closed end defining a space extending therebetween. A piston is slidably disposed in the space dividing the space into a compression chamber and a rebound chamber. A piston rod guide is located in the rebound chamber in sealing engagement with the opened end. A piston rod extends into the rebound chamber and is coupled to the piston for moving the piston in the space between a compression stroke and a rebound stroke. A gas cup includes a body slidably located in the compression chamber dividing the compression chamber into a gas compartment and a fluid compartment. The body includes an upper surface, a lower surface, an exterior surface and an interior surface. The body defines an aperture extending through the upper surface and the lower surface. A decoupler is located in the aperture and secured to the body. A bridging member is located between the decoupler and the body and is coupled to the decoupler and the body. The decoupler and the bridging member are made from materials having different elasticity to allow the decoupler to move in the aperture in response to a volumetric change in the damper assembly and to provide variable tuning of the damper assembly.

Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a damper assembly <NUM> for use in a vehicle constructed in accordance with one embodiment of the present invention is generally shown in <FIG>.

<FIG> illustrates a fragment of an exemplary vehicle suspension including the damper assembly <NUM> being attached to a vehicle chassis <NUM> via a top mount <NUM> and a number of screws <NUM> disposed on a periphery of an upper surface of the top mount <NUM>. The top mount <NUM> connects to a coil spring <NUM>. The damper assembly <NUM> connects to the steering knuckle <NUM> supporting vehicle wheel <NUM>.

As best illustrated in <FIG>, the damper assembly <NUM> comprises a housing <NUM>, having a generally cylindrical shape, disposed on a center axis A and extending between an opened end <NUM> and a closed end <NUM>. The housing <NUM> defines a space <NUM>, <NUM>, <NUM> extending along the center axis A between the opened end <NUM> and the closed end <NUM> for containing a working fluid. A mounting ring <NUM>, having a generally circular shape, couples to the closed end <NUM> for securing the housing <NUM> to the vehicle.

A piston <NUM>, having a generally cylindrical shape, slidably disposed in the space <NUM>, <NUM>, <NUM> dividing the space <NUM>, <NUM>, <NUM> into a compression chamber <NUM>, <NUM> and a rebound chamber <NUM>. The compression chamber <NUM>, <NUM> extends between the closed end <NUM> and the piston <NUM>. The rebound chamber <NUM> extends between the opened end <NUM> and the piston <NUM>.

A gas cup <NUM> includes a body <NUM>, having a generally cylindrical shape, slidably located in the compression chamber <NUM>, <NUM> and spaced apart from the piston <NUM>. The gas cup <NUM> divides the compression chamber <NUM>, <NUM> into a gas compartment <NUM> and a fluid compartment <NUM>. The gas compartment <NUM> extends between the closed end <NUM> and the gas cup <NUM> for containing a gas. It should be noted that the gas can be pressurized in the gas compartment. The fluid compartment <NUM> extends between the gas cup <NUM> and the piston <NUM> for containing the working fluid. In other words, the gas cup <NUM> separates the working fluid and the pressurized gas to compensate for the volumetric change in the fluid compartment <NUM> and the rebound chamber <NUM> to absorb pressure pulse, damp hydraulic impact, and store energy to provide a damping force. It should be noted that the applications can be included in passive shock absorber, semi-active suspension systems, active suspension systems, hydraulic pump, actuator, and accumulator which operates with fluids such as oil and water.

As best shown in <FIG>, the body <NUM> defines an aperture <NUM> extending along the center axis A and through the body <NUM> to allow fluid communication between the gas compartment <NUM> and the fluid compartment <NUM>. The body <NUM> includes an upper surface <NUM>, a lower surface <NUM>, an exterior surface <NUM>, and an interior surface <NUM>. The upper surface <NUM> faces the piston <NUM>. The lower surface <NUM> faces the closed end <NUM>. The exterior surface <NUM> extends between the upper surface <NUM> and the lower surface <NUM> and annularly about the center axis A facing the housing <NUM>. The interior surface <NUM> is radially spaced from the exterior surface <NUM> extending between the upper surface <NUM> and the lower surface <NUM> and annularly about the center axis A to define the aperture <NUM>. The exterior surface <NUM> defines a pair of grooves <NUM>, <NUM> including an upper groove <NUM> and a lower groove <NUM>. The upper groove <NUM> and the lower groove <NUM> are axially spaced apart from one another extending annularly about the body <NUM>. The upper groove <NUM> is located adjacent to the upper surface <NUM>. The lower groove <NUM> is located adjacent to the lower surface <NUM>. A guiding ring <NUM> is located in the upper groove <NUM> extending about the center axis A for engaging the housing <NUM>. A seal ring <NUM> is located in the lower groove <NUM> extending about the center axis A and in an abutment relationship with the housing <NUM> for preventing gas in the gas compartment for leaking between the exterior surface <NUM> of the body <NUM> and the housing <NUM>.

A decoupler <NUM>, having a generally circular shape, is located in the aperture <NUM> and secured to the interior surface <NUM> of the body <NUM> to separate the gas compartment <NUM> from the fluid compartment <NUM> for compensating volumetric fluid change in the fluid compartment <NUM> and the rebound chamber <NUM>. At least one stopper <NUM>, <NUM> is located in the aperture <NUM> coupled to the interior surface <NUM> for restricting movement of the decoupler <NUM>. The at least one stopper <NUM>, <NUM> includes an upper stopper <NUM> and a lower stopper <NUM>. The upper stopper <NUM> is located adjacent to the upper surface <NUM> coupled to the interior surface <NUM> of the body <NUM> for restricting an axial movement of the decoupler <NUM> toward the upper surface <NUM>. The lower stopper <NUM> is located adjacent to the lower surface <NUM> coupled to the interior surface <NUM> of the body <NUM> for restricting an axial movement of the decoupler toward the lower surface <NUM>.

Referring back to <FIG>, the damper assembly <NUM> includes a piston rod guide <NUM> is located in the rebound chamber <NUM> and adjacent to the opened end <NUM> of the housing <NUM>. The piston rod guide <NUM> is in sealing engagement with the opened end <NUM> of the housing <NUM> to close the space <NUM>, <NUM>, <NUM>. The piston rod guide <NUM> defines a bore <NUM>, having a generally cylindrical shape, extending along the center axis A and in communication with the rebound chamber <NUM>.

A piston rod <NUM>, having a generally cylindrical shape, extends along the center axis A, through the bore <NUM>, and into the rebound chamber <NUM> to a distal end <NUM>. The piston rod <NUM> couples to the piston <NUM> for moving the piston <NUM> in the space <NUM>, <NUM>, <NUM> between a compression stroke and a rebound stroke. The compression stroke is defined as the piston rod <NUM> and the piston <NUM> move towards the closed end <NUM>. The rebound stroke is defined as the piston rod <NUM> and the piston <NUM> move toward the opened end <NUM>. A projection <NUM> extends outwardly from the distal end <NUM> of the piston rod <NUM> and through the piston <NUM> to a terminal end <NUM>, spaced part from the piston <NUM>, to couple the piston <NUM> to the piston rod <NUM>. The piston <NUM> defines a hole <NUM>, having a generally cylindrical shape, extending along the center axis A and receiving the projection <NUM> to allow the projection <NUM> to extend through the piston <NUM>. A retaining member <NUM> is disposed at the terminal end <NUM> coupled to the projection <NUM> to secure the piston <NUM> to the piston rod <NUM>.

The piston <NUM> has a compression surface <NUM> and a rebound surface <NUM>. The compression surface <NUM> is located in the compression chamber <NUM>, <NUM> facing the closed end <NUM>. The rebound surface <NUM> is located in the rebound chamber <NUM> facing the opened end <NUM>. The piston <NUM> defines a plurality of channels <NUM>, <NUM> for allowing the working fluid to flow through the piston <NUM> during the compression stroke and the rebound stroke. The plurality of channels <NUM>, <NUM> includes a set of compression channels <NUM> and a set of rebound channels <NUM> extending through the piston <NUM> for allowing the working fluid to flow through the piston <NUM> during the compression stroke and the rebound stroke. The set of compression channels <NUM>, located adjacent to an outer surface <NUM> of the piston <NUM>, is disposed about the center axis A and circumferentially spaced from one another. The compression channels <NUM> extend from the compression surface <NUM> to the rebound surface <NUM> in a parallel relationship with the center axis A. The set of rebound channels <NUM>, radially spaced apart from the set of compression channels <NUM> extends from the compression surface <NUM> to the rebound surface <NUM> parallel to the center axis A.

A compression valve <NUM> includes a plurality of discs, each having a generally circular shape, disposed on the rebound surface <NUM> of the piston <NUM> covering the set of compression channels <NUM> for limiting working fluid flow through the piston <NUM> during the compression stroke to provide a damping force during the compression stroke. A rebound valve <NUM> includes a plurality of discs, each having a generally circular shape, disposed on the compression surface <NUM> covering the rebound channels <NUM> for limiting working fluid flow through the piston <NUM> during the rebound stroke to provide a damping force during the rebound stroke.

Referring back to <FIG>, a bridging member <NUM> is located between the decoupler <NUM> and the interior surface <NUM> of the body <NUM> coupled to the decoupler <NUM> and the body <NUM> to secure the decoupler <NUM> to the body <NUM>. The decoupler <NUM> and the bridging member <NUM> are made from materials having different elasticity to allow the decoupler <NUM> to move in the aperture <NUM> in response to a volumetric change in the damper assembly <NUM> and to provide variable tuning of the damper assembly <NUM>. For example, the decoupler <NUM> can be made from a rigid material and the bridging member <NUM> can be made from an elastic material to allow the decoupler <NUM> to move in the aperture <NUM> in response to the volumetric change in the fluid compartment <NUM> and the rebound chamber <NUM>.

According to an embodiment of the present invention, the decoupler <NUM> can be made from a lightweight rigid material while the bridging member <NUM> can be made from an elastomeric material. In other words, the flexible material used in the gas cup <NUM> is the bridging member <NUM>. According to an embodiment of the present invention, the decoupler <NUM> may not entirely comprise of an elastomeric material. For example, the center of the decoupler <NUM> can be thin aluminum plate wherein engineered rubber/elastomeric material can be bonded to an outer edge of the aluminum plate for movement and component travel. It should be noted that rubber/elastomeric material's shape and compound can be key to the decoupler's <NUM> functionality and durability. With this arrangement, the present invention significant reduces potential gas loss/leak in the gas compartment <NUM> due to the gas permeability characteristics of a decoupler <NUM> of a conventional gas cup which is made entirely from an elastomeric material. According to an embodiment of the present invention, the bridging member <NUM> extends radially inwardly from the interior surface <NUM> toward the center axis to a bridging member end <NUM>. The bridging member end <NUM> is coupled to the decoupler <NUM>. According to an embodiment of the present invention, bridging member end <NUM> defines a slot <NUM> extending annularly about the center axis A and the decoupler <NUM> is received in the slot <NUM>.

The upper stopper <NUM> extends radially inwardly toward the center axis A having an arcuate shaped cross-section with a first curvature whereby the first curvature of the upper stopper <NUM> matches a deformation of the bridging member <NUM> toward the upper surface <NUM> of the body <NUM>. The lower stopper <NUM> extends radially inwardly toward the center axis A and having an arcuate shaped cross-section with a second curvature whereby the second curvature of the lower stopper <NUM> matches a deformation of the bridging member <NUM> toward the lower surface <NUM> of the body <NUM>. In other words, the uniquely shaped stoppers <NUM>, <NUM> are installed adjacent to both upper and lower sides of the decoupler <NUM>. According to an embodiment of the present invention, the stoppers <NUM>, <NUM> can be made of rigid material and securely positioned in the gas cup <NUM>. The primary purpose of the stoppers <NUM>, <NUM> is to limit the axial movement of the bridging member <NUM> and the decoupler <NUM> and to protect the bridging member <NUM> and the decoupler <NUM> from being overstretched during the compression stroke and the rebound stroke. It should be appreciated that the first curvature of the upper stopper <NUM> and a second curvature of the lower stopper <NUM> are designed to match the deformed shape of the bridging member <NUM> even after the decoupler <NUM> contacts the stoppers <NUM>, <NUM> this is because the working fluid pressure can continue to apply to the bridging member <NUM>. Accordingly, this arrangement can be used when the gas cup <NUM> needs to temporarily support charged gas pressure until fluid is filled in the fluid compartment <NUM> and the rebound chamber <NUM> wherein the fluid compartment <NUM> and the rebound chamber <NUM> and the gas compartment <NUM> reach equilibrium pressure. Without the curvature, the bridging member <NUM> can be overstretched until it bottoms out the stoppers <NUM>, <NUM> and thereby, reducing the operational life of the damper assembly <NUM>.

The interior surface <NUM> of the body <NUM> defines an upper recess <NUM> and a lower recess <NUM>. The upper recess <NUM> is located in the fluid compartment <NUM> and adjacent to the upper surface <NUM> of the body <NUM> and extending annularly about the center axis A for receiving the upper stopper <NUM> and secure the upper stopper <NUM> to the interior surface <NUM> of the body <NUM>. The lower recess <NUM> is located in the gas compartment <NUM> extending annularly about the center axis A for receiving the lower stopper <NUM> and secure the lower stopper to the interior surface of the body <NUM>. In other words, the upper stopper <NUM> and the lower stopper <NUM> are installed in the upper and lower side of the decoupler <NUM>. The stoppers <NUM>, <NUM> can be made of rigid material and securely positioned in the gas cup <NUM>. The main purpose of the stoppers <NUM>, <NUM> is to protect rubber bridge being overstretched during the operation. According to an embodiment of the present invention, an inner diameter of the stoppers <NUM>, <NUM> are smaller than a diameter of the decoupler <NUM> whereby the decoupler <NUM> movement in both axial directions are restricted once the decoupler <NUM> contact stoppers <NUM>, <NUM>. The bridging member <NUM> is designed to provide certain stiffness to meet a specific application requirements wherein the gas cup <NUM> will move in the compression chamber <NUM>, <NUM> before the disc fully contacts the stoppers <NUM>, <NUM>. In the event of extreme conditions such as high-speed input, the axial movement of the decoupler <NUM> is restricted by the stoppers <NUM>, <NUM> to prevent the bridging member <NUM> from being overstretched.

The bridging member <NUM>, the decoupler <NUM>, and the stoppers <NUM>, <NUM> also offer variable tuning options for the gas cup <NUM> and the damping assembly <NUM> to improve ride comfort of the user. For instance, during the operation of the damper assembly <NUM>, a force of greater than 8N during the compression stroke or rebound stroke can move the gas cup <NUM> inside the housing <NUM>. As the gas cup <NUM> slides in the housing <NUM>, the gas cup <NUM> is able to provide an additional damping force to compensate for the volumetric change in the housing <NUM> caused by the compression stroke and the rebound stroke. In the event that the force is less than 8N, i.e. when the vehicle is traveling on a smooth road, the bridging member <NUM>, the decoupler <NUM>, and the stoppers <NUM>, <NUM> can provide the damping force to compensate for the small volumetric change in the housing <NUM> caused by the compression stroke and the rebound stroke.

According to an embodiment of the present invention, the tuning can be achieved by varying the elasticity of the bridging member <NUM> and/or the decoupler <NUM>. For example, to increase the axial movement of the bridging member <NUM> and/or the decoupler <NUM>, a more elastic material can be used to form the bridging member <NUM> and/or the decoupler <NUM>. This arrangement allows the bridging member <NUM> and the decoupler <NUM> to compensate for greater volumetric changes in the housing <NUM> caused by the compression stroke and the rebound stroke, i.e. when vehicle is traveling on a rougher road. On the other hand, to reduce the axial movement of the bridging member <NUM> and/or the decoupler <NUM>, the bridging member <NUM> and/or the decoupler <NUM> can be made from a less elastic material. This arrangement allows the bridging member <NUM> and the decoupler <NUM> to compensate for a smaller volumetric change in the housing <NUM>, i.e. when vehicle is traveling on a smoother road.

Additionally, the tuning of the gas cup <NUM> can be achieved by varying the distances of the stoppers <NUM>, <NUM> relative to the bridging member <NUM> and the decoupler <NUM>. In other words, the upper stopper <NUM> and the lower stopper <NUM> are independently movable relative to the bridging member <NUM> and the decoupler <NUM> to adjust the amplitude of the axial movement of the bridging member <NUM> and the decoupler <NUM>. For example, to restrict the axial movement of the bridging member <NUM> and the decoupler <NUM>, the stoppers <NUM>, <NUM> can be closer to the bridging member <NUM> and the decoupler <NUM>. On the other hand, to increase the axial movement of the bridging member <NUM> and the decoupler <NUM>, the upper stopper <NUM> and the lower stopper <NUM> can be axially spaced apart from the bridging member <NUM> and the decoupler <NUM>. In summary, the tuning of the gas cup <NUM> can be achieved by varying three different parameters, e.g. the material composition of the decoupler <NUM>, the material composition of the bridging member <NUM>, and/or the distance of the stoppers <NUM>, <NUM> relative to the bridging member <NUM> and the decoupler <NUM>. These arrangements offer different tuning options for the gas cup <NUM> and the damper assembly <NUM>.

The upper stopper <NUM> defines a first orifice <NUM> bounded by a first periphery <NUM>. The first orifice <NUM> is in fluid communication with the fluid compartment <NUM>. According to an embodiment of the present invention, the first periphery <NUM> of the first orifice <NUM> extends sinusoidally and annularly about the center axis A. According to an embodiment of the present invention, the first periphery <NUM> defines a plurality of first peaks <NUM> and a plurality of first troughs <NUM> disposed about the center axis A. The lower stopper <NUM> defines a second orifice <NUM> bounded by a second periphery <NUM>. The second orifice <NUM> is in fluid communication with the gas compartment <NUM>. According to an embodiment of the present invention, the second periphery <NUM> of the second orifice <NUM> extending sinusoidally and annularly about the center axis A. According to an embodiment of the present invention, the second periphery <NUM> defines a plurality of second peaks <NUM> and a plurality of second troughs <NUM> located about the center axis A. In other words, the first orifice <NUM> and the second orifice <NUM> both can have a flower shape. The flower shape is employed to maximize fluid flow into the gas cup <NUM> to help improve response to the pressure fluctuation while limiting the movement of the bridging member <NUM>.

Claim 1:
A gas cup (<NUM>) for a damper assembly (<NUM>) comprising:
a body (<NUM>) including an upper surface (<NUM>), a lower surface (<NUM>), an exterior surface (<NUM>) and an interior surface (<NUM>);
said body (<NUM>) defining an aperture (<NUM>) extending through said upper surface (<NUM>) and said lower surface (<NUM>);
a decoupler (<NUM>) located in said aperture (<NUM>) and secured to said body (<NUM>); and
a bridging member (<NUM>) located between said decoupler (<NUM>) and said body and coupled to said decoupler (<NUM>) and said body (<NUM>), said decoupler (<NUM>) and said bridging member (<NUM>) being made from materials having different elasticity to allow said decoupler (<NUM>) to move in said aperture (<NUM>) in response to a volumetric change in the damper assembly (<NUM>) and to provide variable tuning of the damper assembly (<NUM>),
wherein the gas cup (<NUM>) further includes at least one stopper (<NUM>, <NUM>) located in said aperture (<NUM>) and coupled to said interior surface (<NUM>) for restricting movement of said decoupler (<NUM>),
wherein said at least one stopper (<NUM>, <NUM>) includes an upper stopper (<NUM>) and a lower stopper (<NUM>), said upper stopper (<NUM>) being located adjacent to said upper surface (<NUM>) and coupled to said body (<NUM>) for restricting an axial movement of said decoupler (<NUM>) toward said upper surface (<NUM>); and
said lower stopper (<NUM>) being located adjacent to said lower surface (<NUM>) and coupled to said body (<NUM>) for restricting an axial movement of said decoupler (<NUM>) toward said lower surface (<NUM>),
characterized in that
said upper stopper (<NUM>) defines a first orifice (<NUM>) bounded by a first periphery (<NUM>), said first periphery (<NUM>) extends about a center axis and includes at least one first peak (<NUM>) and at least one first trough (<NUM>).