Patent Description:
Vehicles generally include dampers that are used in conjunction with suspension systems to absorb vibrations that occur while driving the vehicle. In order to absorb the vibrations, dampers are generally connected between a body and the suspension system of the vehicle. A piston is located within the damper. The piston is connected to the vehicle body or the suspension of the vehicle through a piston rod. The damper also includes a damper body that is connected to the suspension system. As the damper is compressed or extended, the piston may limit the flow of damping fluid between rebound and compression chambers that are defined within the damper body in order to produce a damping force that counteracts the vibrations. By further restricting the flow of damping fluid between the rebound and compression chambers of the damper, greater damping forces may be generated by the damper.

Dampers typically include one or more valves that control the flow of fluid during extension and compression motions of the piston. Many current damper designs utilize externally mounted, electromechanical valves to control extension and compression damping. However, internal pressures in such systems can exceed design requirements.

Document <CIT> discloses a damper comprising: a pressure tube extending co-axially about the longitudinal axis and longitudinally between a first pressure tube end and a second pressure tube end; a piston slidably disposed within the pressure tube defining a rebound chamber and a compression chamber; an outer tube disposed around the pressure tube to define a fluid transport chamber between the pressure tube and the outer tube, the outer tube extending longitudinally between a first outer tube end and a second outer tube end; an intake valve assembly positioned within the outer tube and extending longitudinally between a first intake valve assembly end and a second intake valve assembly end, the intake valve assembly including at least one intermediate chamber disposed in fluid communication with the compression chamber via an intermediate passageway extending within the intake valve assembly; and an accumulation chamber positioned longitudinally between the intake valve assembly and the second outer tube end.

In accordance with one aspect of the present disclosure, a damper is provided. The damper includes a pressure tube that extends co-axially about a longitudinal axis and longitudinally between first and second pressure tube ends. The damper includes a piston slidably disposed within the pressure tube. The piston defines a rebound chamber and a compression chamber within the pressure tube. The rebound chamber is longitudinally positioned between the piston and the first pressure tube end and the compression chamber is longitudinally positioned between the piston and the second pressure tube end. The piston extends longitudinally between a first piston end that faces the rebound chamber and a second piston end that faces the compression chamber. A piston rod extends co-axially with the longitudinal axis between a first piston rod end and second piston rod end. The second piston rod end is fixedly coupled to the piston. The damper also includes an outer tube disposed around the pressure tube. The outer tube extends longitudinally between first and second outer tube ends.

The damper includes an intake valve assembly that is positioned at the second pressure tube end and an accumulation chamber that is positioned longitudinally between the intake valve assembly and the second outer tube end. An intermediate chamber is defined by the intake valve assembly at a position between the compression chamber and the accumulation chamber. The intake valve assembly includes an intermediate passageway that extends longitudinally through the intake valve assembly and that is arranged in fluid communication with the intermediate chamber and the compression chamber.

The damper has at least one control valve that is externally mounted to the outer tube. The control valve has a control valve inlet that is arranged in fluid communication with the intermediate chamber and a control valve outlet that is arranged in fluid communication with both the fluid transport chamber and the accumulation chamber. One or more rebound chamber pressure relief passageways extend through the piston from the rebound chamber to the compression chamber and one or more compression chamber pressure relief passageways extend through the intake valve assembly between the intermediate passageway and the accumulation chamber. The damper further includes a rebound chamber pressure relief valve that is configured to permit fluid flow through the rebound chamber pressure relief passageway(s) in one direction from the rebound chamber to the compression chamber when fluid pressure in the rebound chamber exceeds a blow-off pressure threshold of the rebound chamber pressure relief valve. The damper also includes a compression chamber pressure relief valve that is configured to permit fluid flow through the compression chamber pressure relief passageway(s) in one direction from the intermediate passageway to the accumulation chamber when fluid pressure in the compression chamber exceeds a blow-off pressure threshold of the compression chamber pressure relief valve.

In accordance with another aspect of the present disclosure, the rebound chamber pressure relief valve comprises at least one rebound chamber pressure relief passageway that extends through the piston from the first piston end to the second piston end, a plunger bore that extends longitudinally within the second piston rod end, a plunger extending longitudinally between a first plunger end that is slidably received in the plunger bore and a second plunger end that extends out from the plunger bore into the compression chamber, a valve head that is fixedly coupled to the second plunger end, and a spring positioned in the plunger bore that biases the plunger towards the first piston rod end such that the plunger pulls the valve head against the second piston end to obstruct fluid flow through the at least one rebound chamber pressure relief passageway in a rebound chamber pressure relief valve closed position.

In accordance with another aspect of the present disclosure, the compression chamber pressure relief valve comprises at least one compression chamber pressure relief passageway that extends through the intake valve assembly between the intermediate passageway and the accumulation chamber, a plunger cavity that extends longitudinally within the intake valve assembly, a plunger extending longitudinally between a first plunger end that is slidably received in the plunger cavity and a second plunger end that extends out from the plunger cavity into the accumulation chamber, a valve head that is fixedly coupled to the second plunger end, and a spring positioned in the plunger cavity that biases the plunger away from the second outer tube end such that the plunger pulls the valve head against the second intake valve assembly end to obstruct fluid flow through the at least one compression chamber pressure relief passageway in a compression chamber pressure relief valve closed position.

Advantageously, the way in which the rebound chamber pressure relief valve is constructed and positioned inside the piston and the second piston rod end adds rebound chamber pressure relief (i.e., blow-off) functionality to the damper over and above the flowrate capabilities of the intake valve assembly and the external control valve(s) without reducing or limiting the amount of travel permitted by the damper or increasing the overall length of the damper. Similarly, the way in which the compression chamber relief valve is constructed and positioned inside the intake valve assembly adds compression chamber pressure relief (i.e., blow-off) functionality to the damper over and above the flowrate capabilities of the intake valve assembly and the external control valve(s) without reducing or limiting the amount of travel permitted by the damper or increasing the overall length of the damper.

Wherever possible, the same reference numbers will be used throughout the drawings to refer to same or like parts.

<FIG> and <FIG> illustrate an exemplary damper <NUM> for a vehicle (not shown). The damper <NUM> contains a fluid, such as hydraulic fluid or oil, by way of example and without limitation. The damper <NUM> includes a pressure tube <NUM> that extends longitudinally between a first pressure tube end <NUM> and a second pressure tube end <NUM>. A piston <NUM> is slidably disposed within the pressure tube <NUM>. The piston <NUM> defines a rebound chamber <NUM> and a compression chamber <NUM> within the pressure tube <NUM>. Each of the rebound and compression chambers <NUM>, <NUM> contain the fluid therein. The rebound chamber <NUM> is positioned longitudinally between the piston <NUM> and the first pressure tube end <NUM> while the compression chamber <NUM> is positioned longitudinally between the piston <NUM> and the second pressure tube end <NUM>. The volume of the rebound and compression chambers <NUM>, <NUM> varies based on the movement of the piston <NUM>. The piston <NUM> has a cylindrical surface that seals against the inside of the pressure tube <NUM> and extends longitudinally between a first piston end <NUM> that faces the rebound chamber <NUM> and a second piston end <NUM> that faces the compression chamber <NUM>.

The damper <NUM> includes a piston rod <NUM>. The piston rod <NUM> is coaxially aligned with and defines a longitudinal axis A. The piston rod <NUM> extends longitudinally between a first piston rod end 135a that is configured to be connected to a component of the suspension system <NUM> or the body <NUM> of the vehicle <NUM> and a second piston rod end 135b that is connected to the piston <NUM>.

The damper <NUM> also includes an outer tube <NUM> disposed annularly around the pressure tube <NUM> and includes an inner cylindrical surface <NUM> that faces and is spaced from the pressure tube <NUM>. In some embodiments, including the one shown, the outer tube <NUM> is concentrically disposed around the pressure tube <NUM> about the longitudinal axis A. The outer tube <NUM> extends longitudinally between a first outer tube end <NUM> and a second outer tube end <NUM>. The piston rod <NUM> extends longitudinally out through the first outer tube end <NUM>. The outer tube <NUM> includes a closed portion <NUM> at the second outer tube end <NUM> and a cylindrical portion <NUM> that extends from the first outer tube end <NUM> to the closed portion <NUM> at the second outer tube end <NUM>. Optionally, an attachment fitting <NUM> is mounted to the closed portion <NUM> of the outer tube <NUM>. The attachment fitting <NUM> may be provided in the form of a hole, loop, threaded stud, or other attachment structure and is configured to attach to a component of the suspension system <NUM> or the body <NUM> of the vehicle <NUM>. Optionally, a spring seat <NUM> is mounted to and extends annularly from the outer tube <NUM> at a location adjacent to the first outer tube end <NUM>. The spring seat <NUM> may be provided to configure the damper <NUM> such that it may be used in a coil-over arrangement, where the spring seat <NUM> supports one end of a coil spring of a vehicle suspension system (not shown).

The damper <NUM> includes a fluid transport chamber <NUM> that is disposed between the pressure tube <NUM> and the outer tube <NUM>. The piston rod <NUM> extends longitudinally through a rod guide <NUM>, which is positioned at the first outer tube end <NUM>. Portions of the rod guide <NUM> mate with the first outer tube end <NUM> and the first pressure tube end <NUM>. Just inboard of the rod guide <NUM>, the first pressure tube end <NUM> includes one or more openings <NUM> that provide fluid communication between the rebound chamber <NUM> and the fluid transport chamber <NUM>. Stated another way, the fluid transport chamber <NUM> is arranged in fluid communication with the rebound chamber <NUM> via the openings <NUM> in the first pressure tube end <NUM>.

The damper <NUM> further includes a cover member <NUM> that is attached to the outer cylindrical surface <NUM> of the outer tube <NUM>. By way of example and without limitation, the cover member <NUM> may be welded to the outer cylindrical surface <NUM> of the outer tube <NUM>. A collector chamber <NUM> is defined between the cover member <NUM> and the outer tube <NUM>. Thus, in accordance with this arrangement, the collector chamber <NUM> is positioned external to (i.e., radially outward of) the outer tube <NUM>. Optionally, a charge fitting <NUM> may be provided on the cover member <NUM> to provide a location where the collector chamber <NUM> can be filled or re-filled with hydraulic fluid or oil.

First and second control valves 164a, 164b are externally mounted to the cover member <NUM> on the outer tube <NUM>. Although other types of control valves can be used, in the illustrated embodiment the first and second control valves 164a, 164b are electro-mechanical valves. The operation of the first and second control valves 164a, 164b will be explained in greater detail below, but at a high level, the first and second control valves 164a, 164b regulate two fluid flow paths that can transport fluid into and out of the collector chamber <NUM>. The first control valve 264a has a first control valve axis VA1 and the second control valve 264b has a second control valve axis VA2. The first and second control valve axes VA1 and VA2 are parallel and longitudinally spaced apart from one another, are circumferentially aligned with one another along a control valve alignment axis AA, and are arranged perpendicular to the longitudinal axis A and the control valve alignment axis AA. In other words, both the first and second control valve axes VA1 and VA2 intersect the longitudinal axis A and the control valve alignment axis AA.

In the illustrated example, the collector chamber <NUM> has a limited circumferential extent that extends about the outer tube in an arc <NUM> that is less than or equal to <NUM> degrees. In other words, the collector chamber <NUM> in the illustrated example runs longitudinally along the outer tube <NUM> on each side of the control valve alignment axis AA. The outer tube <NUM> has an outer tube length OL that is measured longitudinally between the first and second outer tube ends <NUM>, <NUM> and the collector chamber <NUM> has a collector chamber length CL that is measured longitudinally between first and second collector ends <NUM>, <NUM>. The collector chamber length CL is shorter than the outer tube length OL. In other words, the collector chamber <NUM> is shorter than the outer tube <NUM> and does not run along the entire length of the outer tube <NUM>.

With additional reference to <FIG>, the damper <NUM> includes an intake valve assembly <NUM> that is disposed inside the outer tube <NUM> and extends longitudinally between a first intake valve assembly end <NUM> and a second intake valve assembly end <NUM>. The intake valve assembly <NUM> includes an adapter body <NUM> at the first intake valve assembly end <NUM>, a first intake valve body 155a that abuts the adapter body <NUM>, a second valve body 155b that abuts the first intake valve body 155a, a divider body 155c at the second intake valve assembly end <NUM>, and a retainer body 155d that is positioned longitudinally between the second intake valve body 155b and the divider body 155c in an abutting arrangement. The retainer body 155d includes a tubular stem <NUM> that extends longitudinally towards the first intake valve assembly end <NUM> and defines an intermediate passageway 158a therein. The adapter body <NUM> is press-fit onto the second pressure tube end <NUM>. In addition, the adapter body <NUM> and the first and second intake valve bodies 155a, 155b are slid over and supported by the tubular stem <NUM> of the of the retainer body 155d and a retainer ring <NUM> snaps into a circumferentially extending groove in the tubular stem <NUM> to secure the adapter body <NUM> and the first and second intake valve bodies 155a, 155b on the tubular stem <NUM> of the of the retainer body 155d. The first and second intake valve bodies 155a, 155b and the divider body 155c abut the inner cylindrical surface <NUM> of the outer tube <NUM> to define first and second intermediate chambers 159a, 159b inside the outer tube <NUM>.

The first intermediate chamber 159a is positioned longitudinally between the first and second intake valve bodies 155a, 155b and the second intermediate chamber 159b is positioned longitudinally between the second intake valve body 155b and the divider body 155c. An accumulation chamber <NUM> is positioned longitudinally between the divider body 155c and the second outer tube end <NUM>. Thus, the first intake valve body 155a forms a partition between the first intermediate chamber 159a and the fluid transport chamber <NUM>, the second intake valve body 155b forms a partition between the first and second intermediate chambers 159a, 159b, and the divider body 155c forms a partition between the second intermediate chamber 159b and the accumulation chamber <NUM>.

The intake valve assembly <NUM> also includes a first intake valve 165a that is mounted to the first intake valve body 155a and a second intake valve 165b that is mounted to the second intake valve body 155b. The intermediate passageway 158a in the tubular stem <NUM> of the of the retainer body 155d extends longitudinally through the intake valve assembly <NUM> from the first intake valve assembly end <NUM>, through adapter body <NUM>, through the first and second intake valve bodies 155a, 155b, and through the retainer body 155d to the second intake valve assembly end <NUM>. As such, the intermediate passageway 158a extends longitudinally through the intake valve assembly <NUM> and is arranged in fluid communication with the compression chamber <NUM> and the second intermediate chamber 159b.

The first intake valve 165a controls fluid flow through the intake valve assembly <NUM> between the first intermediate chamber 159a and the fluid transport chamber <NUM> while the second intake valve 165b controls fluid flow through the intake valve assembly <NUM> between the first intermediate chamber 159a and the second intermediate chamber 159b, which leads to the intermediate passageway 158a and ultimately the compression chamber <NUM>.

In accordance with the illustrated embodiment, the damper <NUM> includes an accumulator insert <NUM> that is disposed within the second outer tube end <NUM>. The accumulator insert <NUM> includes an accumulator sleeve <NUM>, a floating piston <NUM>, and a pressurized chamber (e.g., a gas chamber) <NUM>. The accumulator sleeve <NUM> is positioned inside the outer tube <NUM> and extends between a closed end <NUM> adjacent to the second outer tube end <NUM> and an open end <NUM> adjacent to the intake valve assembly <NUM>. The floating piston <NUM> is preassembled inside the accumulator sleeve <NUM> in a sliding fit. The pressurized chamber <NUM> is separated from the accumulation chamber <NUM> by the floating piston <NUM>. Therefore, the accumulation chamber <NUM> is positioned longitudinally between the intake valve assembly <NUM> and the floating piston <NUM> and the pressurized chamber <NUM> is positioned longitudinally between the floating piston <NUM> and the closed end <NUM>. The pressurized chamber <NUM> contains a pressurized fluid, such as a gas, that operates to bias the floating piston <NUM> towards the intake valve assembly <NUM>.

The accumulator sleeve <NUM> extends longitudinally between the second outer tube end <NUM> and the intake valve assembly <NUM> such that the closed end <NUM> of the accumulator sleeve <NUM> abuts (i.e., contacts) the closed portion <NUM> of the second outer tube end <NUM> and such that the open end <NUM> of the accumulator sleeve <NUM> abuts the divider body 155c of the intake valve assembly <NUM>. Accordingly, the intake valve assembly <NUM> is clamped between the open end <NUM> of the accumulator sleeve <NUM> and the second pressure tube end <NUM> of pressure tube <NUM>. In accordance with this arrangement, the first and second intake valve bodies 155a, 155b and the divider body 155c do not need to be mechanically attached to the outer tube <NUM> (such as by welding) because the intake valve assembly <NUM> is held in place by the accumulator sleeve <NUM> and the pressure tube <NUM>.

With reference to <FIG>, the first control valve 164a has a first control valve inlet 170a that is arranged in fluid communication with the fluid transport chamber <NUM> between the inner and outer tubes <NUM>, <NUM> and a first control valve outlet 172a that is arranged in fluid communication with the collector chamber <NUM>. A first control valve port <NUM> in the outer tube <NUM> is arranged in fluid communication with and extends between the fluid transport chamber <NUM> and the first control valve inlet 170a. The second control valve 164b has a second control valve inlet 170b that is arranged in fluid communication with the second intermediate chamber 159b and a second control valve outlet 172b that is arranged in fluid communication with the collector chamber <NUM>. A second control valve port <NUM> in the outer tube <NUM> is arranged in fluid communication with and extends between the second intermediate chamber 159b and the second control valve inlet 170b. The first control valve 164a therefore regulates fluid flow from the fluid transport chamber <NUM> to the collector chamber <NUM> and the second control valve 164b regulates fluid flow from the second intermediate chamber 159b to the collector chamber <NUM>.

One or more accumulator ports <NUM> in the outer tube <NUM> are arranged in fluid communication with and extend between the collector chamber <NUM> and the accumulation chamber <NUM>, while one or more open ports <NUM> in the outer tube <NUM> are arranged in fluid communication with and extend between the collector chamber <NUM> and the first intermediate chamber 159a. In other words, the accumulator chamber <NUM> is arranged in fluid communication with the collector chamber <NUM> via the accumulator port(s) <NUM> in the outer tube <NUM> and the first intermediate chamber 159a is arranged in fluid communication with the collector chamber <NUM> via the open port(s) <NUM> in the outer tube <NUM>. The accumulator port(s) <NUM> and open port(s) <NUM> in the outer tube <NUM> are provided in the form of open holes, slots, or apertures that are not open or closed by a valve. As such, fluid may freely flow between the collector chamber <NUM> and the accumulation chamber <NUM> and between the collector chamber <NUM> and the first intermediate chamber 159a.

In the open position, the first control valve 164a allows fluid communication between the fluid transport chamber <NUM> and the collector chamber <NUM>. More particularly, the first control valve inlet 170a is in fluid communication with the fluid transport chamber <NUM> and the first control valve outlet 172a is in fluid communication with the collector chamber <NUM>. First valve member 171a allows selective fluid communication between the first control valve inlet 170a and the first control valve outlet 172a and therefore selective fluid flow between the fluid transport chamber <NUM> and the collector chamber <NUM>, which ultimately regulates fluid flow from the rebound chamber <NUM> to the compression chamber <NUM>.

In the open position, the second control valve 164b allows fluid communication between the second intermediate chamber 159b and the collector chamber <NUM>. More particularly, the second control valve inlet 170b is in fluid communication with the second intermediate chamber 159b and the second control valve outlet 172b is in fluid communication with the collector chamber <NUM>. Second valve member 171b allows selective fluid communication between the second control valve inlet 170b and the second control valve outlet 172b and therefore selective fluid flow between the second intermediate chamber 159b and the collector chamber <NUM>, which ultimately regulates fluid flow from the compression chamber <NUM> to both the fluid transport chamber <NUM> and the accumulation chamber <NUM>.

As shown in <FIG>, when the piston <NUM> moves towards the intake valve assembly <NUM> during a compression stroke, the volume of the compression chamber <NUM> decreases. The second control valve 164b is actuated to the open position during compression strokes of the damper <NUM> to regulate fluid flow from the second intermediate chamber 159b to the collector chamber <NUM>. Specifically, the degree of opening of the second control valve 164b may be regulated to adjust the compression damping characteristics of the damper <NUM>. At the same time, the first control valve 164a is in the closed position during compression strokes of the damper <NUM>. As a result, there is no communication of fluid directly between the fluid transport chamber <NUM> and the collector chamber <NUM> during a compression stroke.

During a compression stroke, a compression flow path P1 is defined inside the damper <NUM>, where fluid in the compression chamber <NUM> flows through the intermediate passageway 158a in the first intake valve assembly <NUM> and into the second intermediate chamber 159b. Fluid in the second intermediate chamber 159b flows to the second control valve inlet 170b and passes through the second control valve port <NUM> in the outer tube <NUM>. Fluid from the second control valve inlet 170b flows to the second control valve outlet 172b because the second control valve 164b is in the open position and fluid from the second control valve outlet 172b flows into the collector chamber <NUM>. The fluid flowing into the collector chamber <NUM> flows into the accumulation chamber <NUM> via the accumulation port(s) <NUM> in the outer tube <NUM> and into the first intermediate chamber 159a via the open port(s) <NUM> in the outer tube <NUM>. If the pressure differential between the first intermediate chamber 159a and the fluid transport chamber <NUM> exceeds the break pressure of the first intake valve 165a, the first intake valve 165a will open and fluid will flow through a first set of intake orifices 158b in the first intake valve body 155a and into the fluid transport chamber <NUM>. Some of the fluid in the fluid transport chamber <NUM> then flows through the openings <NUM> in the first pressure tube end <NUM> and into the rebound chamber <NUM>, which increases in volume during compression strokes. Also, as a greater length of the piston rod <NUM> moves into the rebound chamber <NUM> during a compression stroke, the volume of the fluid that is displaced by the piston rod <NUM> increases. The fluid that is displaced by the piston rod <NUM> (i.e., the rod volume) flows into the collector chamber <NUM>, through the accumulator port(s) <NUM>, and into the accumulation chamber <NUM>, which causes the floating piston <NUM> to move away from the intake valve assembly <NUM>, increasing the size of the accumulation chamber <NUM>.

As shown in <FIG>, when the piston <NUM> moves away from the intake valve assembly <NUM> during an extension/rebound stroke, the volume of fluid in the compression chamber <NUM> increases. The first control valve 164a is actuated to the open position during extension strokes of the damper <NUM> to regulate fluid flow from the fluid transport chamber <NUM> to the collector chamber <NUM>. Specifically, the degree of opening of the first control valve 164a may be regulated to adjust the extension/rebound damping characteristics of the damper <NUM>. At the same time, the second control valve 164b is in the closed position during extension strokes of the damper <NUM>. As a result, there is no communication of fluid directly between the second intermediate chamber 159b and the collector chamber <NUM> during an extension stroke.

During an extension/rebound stroke, a rebound flow path P2 is defined inside the damper <NUM>, where fluid in the rebound chamber <NUM> flows into the fluid transport chamber <NUM> via the openings <NUM> in the first pressure tube end <NUM> and the fluid in the fluid transport chamber <NUM> then flows to the first control valve inlet 170a and passes through the first control valve port <NUM> in the outer tube <NUM>. Fluid from the first control valve inlet 170a flows to the first control valve outlet 172a because the first control valve 164a is in the open position and fluid from the first control valve outlet 172a flows into the collector chamber <NUM>. Fluid from the collector chamber <NUM> flows into the first intermediate chamber 159a via the open port(s) <NUM> in the outer tube <NUM>. When the pressure differential between the first intermediate chamber 159a and the second intermediate chamber 159b exceeds the break pressure of the second intake valve 165b, the second intake valve 165b will open and fluid in the first intermediate chamber 159a will flow through a second set of intake orifices 158d in the second intake valve body 155b, through the second intermediate chamber 159b, through a plurality of channels <NUM> in the retainer body 155d, through the intermediate passageway 158a in the first intake valve assembly <NUM>, and into the compression chamber <NUM>. Also, the volume that is displaced by the piston rod <NUM> (i.e., the rod volume) decreases during an extension/rebound stroke, so an additional flow of fluid must be supplied from the accumulation chamber <NUM> to compensate for the decrease in the rod volume. Thus, some of the fluid in the accumulation chamber <NUM> flows through the accumulator port(s) <NUM> and into the collector chamber <NUM> where it joins the extension flow path P2. The net flow of fluid out of the accumulation chamber <NUM> causes the floating piston <NUM> to move towards the intake valve assembly <NUM>, decreasing the size of the accumulation chamber <NUM>. Thus, the intake valve assembly <NUM> allows bi-directional flow of fluid to and from the compression chamber <NUM>.

As previously explained, the first and second control valves 164a, 164b are externally mounted on the outer tube <NUM> such that the first and second control valve ports <NUM>, <NUM> are circumferentially aligned with each other on the outer tube <NUM> along the control valve alignment axis AA. To minimize the overall height of the first and second control valves 164a, 164b, the cover member <NUM> may be externally mounted to the outer tube <NUM> in such a way that the cover member abuts / contacts the outer cylindrical surface <NUM> of the outer tube <NUM> along the control valve alignment axis AA. In accordance with this space saving arrangement, the collector chamber <NUM> runs on each side of the control valve alignment axis AA, while the accumulator port(s) <NUM> and the open port(s) <NUM> in the outer tube <NUM> are offset relative to the first and second control valve ports <NUM>, <NUM>, such that the accumulator port(s) <NUM> and the open port(s) <NUM> in the outer tube <NUM> are circumferentially spaced relative to the control valve alignment axis AA. In other words, the ports <NUM>, <NUM>, <NUM>, and <NUM> in the outer tube <NUM> of the damper <NUM> are arranged such that the control valve alignment axis AA bisects the first and second control valve ports <NUM>, <NUM>, but does not bisect the accumulator port(s) <NUM> and the open port(s) <NUM> due to their offset arrangement, which places the accumulator port(s) <NUM> and the open port(s) <NUM> in direct fluid communication with the collector chamber <NUM>.

With reference to <FIG>, the piston <NUM> includes a rebound chamber pressure relief valve <NUM> to limit high internal pressures within the rebound chamber <NUM> and a compression chamber pressure relief valve <NUM> to limit high internal pressures within the compression chamber <NUM>. The piston <NUM> includes one or more rebound chamber pressure relief passageways <NUM> that extend through the piston <NUM> from the rebound chamber <NUM> to the compression chamber <NUM>. The intake valve assembly <NUM> includes one or more compression chamber pressure relief passageways <NUM> that extend through the intake valve assembly <NUM> between the intermediate passageway 158a and the accumulation chamber <NUM>.

The rebound chamber pressure relief valve <NUM> is configured to permit fluid flow through the rebound chamber pressure relief passageway(s) <NUM> in one direction from the rebound chamber <NUM> to the compression chamber <NUM> when fluid pressure in the rebound chamber <NUM> exceeds a blow-off pressure threshold of the rebound chamber pressure relief valve <NUM>. In addition to the rebound chamber pressure relief passageway(s) <NUM>, the rebound chamber pressure relief valve <NUM> includes a plunger bore <NUM> that extends longitudinally within the second piston rod end 135b and a plunger <NUM> that extends longitudinally between a first plunger end <NUM> that is slidably received in the plunger bore <NUM> and a second plunger end <NUM> that extends out from the plunger bore <NUM> into the compression chamber <NUM>. The rebound chamber pressure relief valve <NUM> also includes a valve head <NUM> that is fixedly coupled to the second plunger end <NUM> and a spring <NUM> that is positioned in the plunger bore <NUM>. The spring <NUM> biases the plunger <NUM> towards the first piston rod end 135a such that the plunger <NUM> pulls the valve head <NUM> against the second piston end <NUM> to obstruct fluid flow through the rebound chamber pressure relief passageway(s) <NUM> when the rebound chamber pressure relief valve <NUM> is in a rebound chamber pressure relief valve closed position (as illustrated in <FIG>).

The plunger <NUM> of the rebound chamber pressure relief valve <NUM> includes a first spring seat <NUM> that extends radially out from the first plunger end <NUM> and the piston <NUM> includes a second spring seat <NUM>. The spring <NUM> is a coil-spring that extends helically about the plunger <NUM> and longitudinally between the first and second spring seats <NUM>, <NUM>. When the rebound chamber pressure relief valve <NUM> is fully assembled, the spring <NUM> applies a biasing force to the first plunger end <NUM>, in a direction pointing away from the compression chamber <NUM>, that defines a blow-off pressure threshold of the rebound chamber pressure relief valve <NUM>. The plunger <NUM> and the valve head <NUM> of the rebound chamber pressure relief valve <NUM> are configured to slide longitudinally such that the valve head <NUM> will move away from the second piston end <NUM> and permit fluid flow B2 to pass through the rebound chamber pressure relief passageway(s) <NUM> to define a rebound chamber pressure relief valve open position when fluid pressure in the rebound chamber <NUM> exceeds the blow-off pressure threshold of the rebound chamber pressure relief valve <NUM> (as shown in <FIG>).

As best seen in <FIG> and <FIG>, the rebound chamber pressure relief passageway(s) <NUM> extend through the piston <NUM> at circumferentially spaced locations. Each rebound chamber pressure relief passageway <NUM> has a first rebound passageway opening <NUM> on the first piston end <NUM> and a second rebound passageway opening <NUM> on the second piston end <NUM>. The first rebound passageway openings <NUM> are open and unobstructed and are therefore always arranged in fluid communication with the rebound chamber <NUM>. The second rebound passageways <NUM> on the other hand are open and closed by longitudinal movement of the valve head <NUM> as the valve head <NUM> moves into and out of contact with the second piston end <NUM>. While other configurations are possible, in the illustrated example, the valve head <NUM> is provided in the form of a sealing disc that has a flat, disc-like shape that is secured to the plunger <NUM> by a nut that is threaded onto the second plunger end <NUM>. Because the second piston rod end 135b does not extend longitudinally beyond the second piston end <NUM> into the compression chamber <NUM>, this arrangement of the rebound chamber pressure relief valve <NUM> does not reduce the amount of travel permitted by the damper <NUM> or increase the overall length OL of the damper <NUM>.

The compression chamber pressure relief valve <NUM> is configured to permit fluid flow through the compression chamber pressure relief passageway(s) <NUM> in one direction from the intermediate passageway 158a to the accumulation chamber <NUM> when fluid pressure in the compression chamber <NUM> exceeds a blow-off pressure threshold of the compression chamber pressure relief valve <NUM>. In addition to the compression chamber pressure relief passageway(s) <NUM>, the compression chamber pressure relief valve <NUM> includes a plunger cavity <NUM> that extends longitudinally within the intake valve assembly <NUM> and a plunger <NUM> that extends longitudinally between a first plunger end <NUM> that is slidably received in the plunger cavity <NUM> and a second plunger end <NUM> that extends out from the plunger cavity <NUM> into the accumulation chamber <NUM>. The compression chamber pressure relief valve <NUM> also includes a valve head <NUM> that is fixedly coupled to the second plunger end <NUM> and a spring <NUM> that is positioned in the plunger cavity <NUM>. The spring <NUM> biases the plunger <NUM> away from the second outer tube end <NUM> such that the plunger <NUM> pulls the valve head <NUM> against the divider body 155c at the second intake valve assembly end <NUM> to obstruct fluid flow through the compression chamber pressure relief passageway(s) <NUM> when the compression chamber pressure relief valve <NUM> is in a compression chamber pressure relief valve closed position (as illustrated in <FIG>).

In the illustrated example, the compression chamber pressure relief valve <NUM> further includes a plunger housing <NUM> that extends longitudinally within the intermediate passageway 158a. The plunger housing <NUM> has a tubular shape that defines the plunger cavity <NUM> therein with one closed end and one open end. However, it should be appreciated that other arrangements are possible where the plunger housing <NUM> is eliminated and one or more components of the intake valve assembly <NUM> form the plunger cavity <NUM>. The plunger <NUM> of the compression chamber pressure relief valve <NUM> includes a first spring seat <NUM> that extends radially out from the first plunger end <NUM> and the divider body 155c includes a second spring seat <NUM>. The spring <NUM> is a coil-spring that extends helically about the plunger <NUM> and longitudinally between the first and second spring seats <NUM>, <NUM>. When the compression chamber pressure relief valve <NUM> is fully assembled, the spring <NUM> applies a biasing force to the first plunger end <NUM>, in a direction pointing towards the compression chamber <NUM>, that defines a blow-off pressure threshold of the compression chamber pressure relief valve <NUM>. The plunger <NUM> and the valve head <NUM> of the compression chamber pressure relief valve <NUM> are configured to slide longitudinally such that the valve head <NUM> will move away from the divider body 155c / second intake valve assembly end <NUM> and permit fluid flow B1 to pass through the compression chamber pressure relief passageway(s) <NUM> to define a compression chamber pressure relief valve open position when fluid pressure in the compression chamber <NUM> exceeds the blow-off pressure threshold of the compression chamber pressure relief valve <NUM> (as shown in <FIG>).

As best seen in <FIG> and <FIG>, the compression chamber pressure relief passageway(s) <NUM> extend through the divider body 155c at circumferentially spaced locations. Each compression chamber pressure relief passageway <NUM> has a first compression passageway opening <NUM> and a second compression passageway opening <NUM>. The first compression passageway openings <NUM> on the divider body 155c are open to and arranged in fluid communication with the intermediate passageway 158a and therefore the compression chamber <NUM>. On the other hand, the second compression passageways <NUM> on the divider body 155c are open and closed by longitudinal movement of the valve head <NUM> as the valve head <NUM> moves into and out of contact with the divider body 155c at the second intake valve assembly end <NUM>. While other configurations are possible, in the illustrated example, the valve head <NUM> is provided in the form of a sealing disc that has a flat, disc-like shape that is secured to the plunger <NUM> by a nut that is threaded onto the second plunger end <NUM>. Because the plunger housing <NUM> is positioned inside the intermediate passageway 158a of the intake valve assembly <NUM> and does not extend longitudinally into the compression chamber <NUM>, this arrangement of the compression chamber pressure relief valve <NUM> does not reduce the amount of travel permitted by the damper <NUM> or increase the overall length OL of the damper <NUM>.

With reference to <FIG>, the first and second intake valve bodies 155a, 155b of the intake valve assembly <NUM> are configured as vented discs, whereas the divider body 155c is shaped like a solid disk. In this embodiment, there are no orifices or passages in the divider body 155c. The first intake valve body 155a includes a first center bore 206a that extends through the first intake valve body 155a. The first set of intake orifices 158b are arranged circumferentially around (i.e., are radially outward of) the first center bore 206a. The second intake valve body 155b includes a second center bore 206b that extends through the second intake valve body 155b. The second set of intake orifices 158d are arranged circumferentially around (i.e., are radially outward of) the second center bore 206b. The adapter body <NUM> and the retainer body 155d each have a cylindrical hub portion that directly abuts one of the first and second intake valve bodies 155a, 155b and a disc-like flange portion that retains the first and second intake valves 165a, 165b such that both the adapter body <NUM> and the retainer body 155d have shapes similar to that of a top hat. In addition, the adapter body <NUM> and the retainer body 155d have third and fourth center bores 206c, 206d, respectively. The first center bore 206a in the first intake valve body 155a, the second center bore 206b in the second intake valve body 155b, the third center bore 206c in the adapter body <NUM>, and the fourth center bore 206d in the retainer body 155d are aligned with one another and co-axially aligned with the central longitudinal axis A of the damper <NUM>. The tubular stem <NUM> of the retainer body 155d extends through the first center bore 206a in the first intake valve body 155a, the second center bore 206b in the second intake valve body 155b, the third center bore 206c in the adapter body <NUM>, and the fourth center bore 206d in the retainer body 155d while the fourth center bore 206d in the retainer body 155d defines the intermediate passageway 158a of the intake valve assembly <NUM>. The retainer ring <NUM> snaps into a circumferentially extending groove in the tubular stem <NUM> of the retainer body 155d at a position near the first intake valve assembly end <NUM> to act as a stop that prevents the adapter body <NUM> and the first and second intake valve bodies 155a, 155b from sliding longitudinally on the tubular stem <NUM> of the of the retainer body 155d after final assembly.

Thus, the adapter body <NUM> and the first and second intake valve bodies 155a, 155b can be pre-assembled onto the tubular stem <NUM> of the retainer body 155d prior to insertion into the outer tube <NUM> of the damper <NUM>. Through use of the retainer ring <NUM>, the adapter body <NUM> and the first and second intake valve bodies 155a, 155b can be pre-assembled on the tubular stem <NUM> of the retainer body 155d such that there is a pre-load on the first and second spring disc stacks 167a, 167b without the pre-load driving the components of the pre-assembly apart. However, it should be appreciated that the retainer ring <NUM> could be eliminated and the tubular stem <NUM> of the retainer body 155d could be hammered or otherwise manipulated to produce an outwardly flared, mechanically deformed end to hold the components of the pre-assembly together before the pre-assembly is inserted into the outer tube <NUM> of the damper <NUM>. Either way, manufacturing and assembly of the damper <NUM> is less complicated, more efficient, and more economical because both the intake valve assembly <NUM> and the accumulator insert <NUM> can be pre-assembled prior to installation inside the outer tube <NUM>.

The first intake valve 165a controls fluid flow through the first set of intake orifices 158b between the first intermediate chamber 159a and the fluid transport chamber <NUM>. In the illustrated example, the first intake valve 165a is a passive valve. More specifically, in the illustrated embodiment, the first intake valve 165a includes a first spring disc stack 167a that is retained between the adapter body <NUM> and the first intake valve body 155a. In operation, the first spring disc stack 167a opens and closes the first set of intake orifices 158b by flexing towards and away from the first intake valve body 155a based on a pressure differential between the first intermediate chamber 159a and the fluid transport chamber <NUM>. As a result, the first intake valve 165a acts as a one-way valve that permits fluid flow in only one direction from the first intermediate chamber 159a to the fluid transport chamber <NUM>. This one-way flow through the first intake valve 165a occurs during compression strokes as the piston <NUM> moves toward the intake valve assembly <NUM>.

The second intake valve 165b controls fluid flow through the second set of intake orifices 158d between the first and second intermediate chambers 159a, 159b. In the illustrated example, the second intake valve 165b is a passive valve. More specifically, in the illustrated embodiment, the second intake valve 165b includes a second spring disc stack 167b that is retained between the second intake valve body 155b and the retainer body 155d. In operation, the second spring disc stack 167b opens and closes the second set of intake orifices 158d by flexing towards and away from the second intake valve body 155b based on a pressure differential between the first intermediate chamber 159a and the second intermediate chamber 159b. The second intake valve 165b acts as a one-way valve that permits fluid flow in only one direction from the first intermediate chamber 159a and the second intermediate chamber 159b. This one-way flow through the second intake valve 165b occurs during extension strokes as the piston <NUM> moves away from the intake valve assembly <NUM>. The retainer body 155d includes a plurality of teeth <NUM> that are arranged to abut the divider body 155c. The plurality of teeth <NUM> are circumferentially spaced to define the plurality of channels <NUM> in the retainer body 155d. The channels <NUM> in the retainer body 155d extend radially outwardly away from the central longitudinal axis A and therefore permit fluid flow between the second intermediate chamber 159b and the intermediate passageway 158a.

The rebound and compression dampening rates of the damper <NUM> can be dynamically controlled and adjusted between soft and firm limits by applying electric current to the externally mounted, electromechanical control valves 164a, 164b. However, a mutual relationship / correlation exists between the soft and firm limits due to fluid flow rate limitations through the damper <NUM> and the control valves 164a, 164b, meaning that internal pressures inside the rebound and compression chambers <NUM>, <NUM> can sometimes exceed design limits when the dampening rates of the damper <NUM> are near or at the firm/upper limit of the adjustable dampening rate range. The rebound chamber and compression chamber pressure relief valves <NUM>, <NUM> described herein release excess pressure in the rebound and compression chambers <NUM>, <NUM> such that the fluid pressure does not exceed design limits, improving safety, durability, and performance, without the trade-off of consuming extra space / dead length inside the damper <NUM> that would either reduce the available travel distance of the damper <NUM> or increase its overall length OL. In other words, the rebound chamber and compression chamber pressure relief valves <NUM>, <NUM> described herein are particularly advantageous in that they minimize the extra dead length typically associated with internal pressure relief (i.e., blow-off) valves.

Claim 1:
A damper (<NUM>) comprising:
a pressure tube (<NUM>) extending co-axially about the longitudinal axis and longitudinally between a first pressure tube end (<NUM>) and a second pressure tube end (<NUM>);
a piston (<NUM>) slidably disposed within the pressure tube defining a rebound chamber (<NUM>) and a compression chamber (<NUM>);
an outer tube (<NUM>) disposed around the pressure tube to define a fluid transport chamber (<NUM>) between the pressure tube and the outer tube, the outer tube extending longitudinally between a first outer tube end (<NUM>) and a second outer tube end (<NUM>);
an intake valve assembly (<NUM>) positioned within the outer tube and extending longitudinally between a first intake valve assembly end (<NUM>) and a second intake valve assembly end (<NUM>), the intake valve assembly including at least one intermediate chamber (159a, 159b) disposed in fluid communication with the compression chamber via an intermediate passageway (158a) extending within the intake valve assembly;
an accumulation chamber (<NUM>) positioned longitudinally between the intake valve assembly and the second outer tube end; and
a compression chamber pressure relief valve (<NUM>) comprising at least one compression chamber pressure relief passageway (<NUM>) that extends through the intake valve assembly between the intermediate passageway and the accumulation chamber, a plunger cavity (<NUM>) that extends longitudinally within the intake valve assembly, a plunger (<NUM>) extending longitudinally between a first plunger end (<NUM>) that is slidably received in the plunger cavity and a second plunger end (<NUM>) that extends out from the plunger cavity into the accumulation chamber, a valve head (<NUM>) that is fixedly coupled to the second plunger end, and a spring (<NUM>) positioned in the plunger cavity that biases the plunger away from the second outer tube end such that the plunger pulls the valve head against the second intake valve assembly end to obstruct fluid flow through the at least one compression chamber pressure relief passageway in a compression chamber pressure relief valve closed position.