O-ring lubrication system

A pressure regulator includes a cylinder and a piston contained in the cylinder. First and second O-rings are attached to the cylinder and configured to form a seal between the cylinder and an interior wall of the piston. The pressure regulator has a lubrication system that includes a lubrication reservoir between the first and second O-rings defined by an annular groove in an exterior surface of the piston and the interior wall of the cylinder, and an input port extending through the cylinder to the lubrication reservoir. The piston is configured to move along a central axis relative to the cylinder between first and second positions. The first and second O-rings are displaced from the input port during movement of the piston between the first and second positions.

BACKGROUND

Piston and cylinder arrangements are used in a variety of mechanical devices, such as valves and pressure regulators, for example. O-rings are commonly used to form a seal between an outer wall of the piston and an interior wall of the cylinder, in which the piston is supported for slidable movement relative to the cylinder. The O-rings are typically received within an annular groove of the outer wall of the piston, and slide against the interior wall of the cylinder during movement of the piston relative to the cylinder.

A lubricant, such as grease, is generally coated on the O-rings and the walls of the cylinder and piston to reduce friction between the interior wall of the cylinder and the O-ring. This extends the life of the O-ring and, thus, the operational life of the mechanical device, in which the O-ring is being used.

The amount of lubricant available to lubricate the O-ring is generally reduced over time due to use of the mechanical device. As a result, it is necessary to periodically replenish the lubricant. This generally involves disassembling the mechanical device and applying a new coating of lubricant to the O-rings and the walls of the piston and cylinder.

SUMMARY

Embodiments of the present disclosure are directed to a mechanical device that includes a lubrication system for maintaining lubrication of O-rings of the device during operation.

One mechanical device in accordance with embodiments of the present disclosure is in the form of a pressure regulator that includes a cylinder and a piston contained in the cylinder. First and second O-rings are attached to the cylinder and configured to form a seal between the cylinder and an interior wall of the piston. The pressure regulator has a lubrication system that includes a lubrication reservoir between the first and second O-rings defined by an annular groove in an exterior surface of the piston and the interior wall of the cylinder, and an input port extending through the cylinder to the lubrication reservoir. The piston is configured to move along a central axis relative to the cylinder between first and second positions. The first and second O-rings are displaced from the input port during movement of the piston between the first and second positions.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the present disclosure are described more fully hereinafter with reference to the accompanying drawings. Elements that are identified using the same or similar reference characters refer to the same or similar elements. The various embodiments of the present disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

The terms “about” and “substantially” are used herein with respect to measurable values and ranges due to expected variations known to those skilled in the art (e.g., limitations and variabilities in measurements).

Embodiments of the present disclosure are directed to a mechanical device having an O-ring lubrication system.FIG. 1is a simplified cross-sectional view of an exemplary mechanical device100including an exemplary O-ring lubrication system102, in accordance with embodiments of the present disclosure. The exemplary device100includes a cylindrical piston104and a cylinder106. The piston104is contained within the cylinder106and is configured to slide along a central axis107of the piston104and the cylinder106over a travel length108along the axis107between a first position109A, which is shown in solid lines, and a second position109B, which is shown in phantom lines. Thus, the first and second positions109A and109B correspond to the limits the piston104can travel within the cylinder106along the axis107during operation of the device100.

The device100also includes at least one O-ring110, such as the O-rings110A and110B shown inFIG. 1, each of which is received within a corresponding annular groove111formed in the piston104, such as grooves111A and111B. In some embodiments, the grooves111are each concentric and perpendicular to the central axis107. Each of the O-rings110operates to form a seal between the piston104and an interior wall112of the cylinder106.

The lubrication system102operates to lubricate the O-rings110during use of the device100with a lubricant (e.g., grease). Additionally, the lubrication system102allows the O-rings110of the device100to be periodically replenished with the lubricant without having to disassemble the device100, thereby extending the operating life of the device100while avoiding costly maintenance associated with conventional mechanical devices.

In some embodiments, the device100includes a biasing mechanism114that is configured to bias the piston104toward the first position. The biasing mechanism114may comprise a spring or another suitable biasing mechanism.

The device100may take on many different forms while utilizing the lubrication system102. For example, the device100may take the form of a valve (e.g., solenoid valve), a pressure regulator, an unloader, or another mechanical device. Thus, it is understood that the piston104and the cylinder110shown inFIG. 1may form only a portion of the device100.

FIGS. 2-4illustrate an exemplary mechanical device100in the form of a pressure regulator, with which embodiments of the lubrication system102may be used.FIG. 2is a front view of the pressure regulator100A.FIGS. 3 and 4are cross-sectional views of the pressure regulator100taken generally along line A-A ofFIG. 2. The pressure regulator100A includes an inlet120, an outlet122, and a valve body124attached to the piston104. The piston104is configured to move along the axis114between a closed position109A (FIG. 3), in which the valve body124engages a valve seat126at the outlet122to substantially block the flow of fluid from the inlet120to the outlet122, and an open position109B (FIG. 4), in which the piston104and the valve body124are displaced from the valve seat126to allow fluid to flow from the inlet120to the outlet122.

The piston104is biased toward the valve seat126and the closed position109A using a biasing mechanism114, which may include a spring128contained in a housing130, or other suitable biasing mechanism. When the pressure at the inlet104exceeds a threshold pressure, the force applied to the piston104by the biasing mechanism114is overcome by the fluid pressure, and the piston104is driven along the axis107to displace the valve body124from the valve seat126toward the open position109B, thereby allowing the pressure and the fluid to be released from the inlet120to the outlet126, in accordance with conventional pressure regulators.

The lubrication system102operates to maintain lubrication of the O-rings110A and110B that are attached to the piston104during operation of the pressure regulator100A. The O-rings110A and110B provide a double seal between the piston104and the interior wall112of the cylinder106to prevent fluid from leaking from the inlet120past the piston104.

In some embodiments, the lubrication system102includes a lubrication reservoir130between the O-rings110A and110B.FIG. 5is a side cross-sectional view of a portion of the piston104that includes the reservoir130. In some embodiments, the lubrication reservoir130is formed by an annular groove132in the exterior wall133of the piston104, which may be coaxial to the axis107. In some embodiments, the exterior wall133of the piston104at the reservoir130is displaced a greater distance from the interior wall112of the cylinder106, than the exterior wall of the piston104surrounding the O-rings110A and110B, as shown inFIG. 1.

The lubrication system102also includes an input port140formed in the cylinder wall106, which allows lubricant to be injected into the reservoir130. In some embodiments, the input port140may include a fitting142, such as a zerk fitting or other suitable fitting, that is coupleable to a supply of lubricant143(FIG. 1). The user may inject lubricant from the supply143through the input port140and into the reservoir130. In some embodiments, after the reservoir130is filled with lubricant, the input port140may be sealed using a suitable plug (not shown).

In some embodiments, the lubrication system102includes an output port144through the cylinder wall106that is open to the reservoir130. The output port144allows the reservoir130to be purged of gas and/or liquid during the filling of the reservoir130with lubricant through the input port140. In some embodiments, the output port144may include a fitting145(FIG. 3), such as a zerk fitting or other suitable fitting. The fitting145may, for example, facilitate coupling the output port144to a collector149for collecting lubricant discharged through the output port144, as shown inFIG. 1.

A user may fill the reservoir130by connecting a suitable supply143of lubricant to the input port140and injecting lubricant into the reservoir130from the supply143, as indicated by arrow146. As the reservoir130fills with the lubricant, gas and/or fluid, is purged from the reservoir130through the output port144, as indicated by arrow148. The user knows when the reservoir130is generally filled with the lubricant when lubricant escapes through the output port144. As mentioned above, the lubricant that is discharged through the output port144may be collected by the collector149.

The lubricant supply143comprises a container151containing a volume of lubricant152within an interior chamber154. In some embodiments, the lubricant supply143is directly attached to the device100by a support member155, such as a bracket, a socket (shown), or other suitable support member.

In some embodiments, the volume of the interior chamber154of the container151may be compressed using any suitable technique to drive the lubricant152through the input port140and into the reservoir130. For example, the container151may be compressed by hand to discharge the lubricant152. Other configurations of the lubricant supply143may also be used.

In some embodiments, the lubricant supply143includes a discharge mechanism156for discharging the lubricant152through the input port140and into the reservoir130. Thus, the lubricant supply143may be directly attached to the device100, such as by the support member155, and provide a supply of lubricant to the reservoir130either automatically as the supply of lubricant within the reservoir decreases, or upon actuation by a user of the device100.

The mechanism156may take on any suitable form. In one embodiment, the mechanism156includes a piston158and a spring member159that biases the piston158to discharge the lubricant152from the supply143. A user may actuate the mechanism156using any suitable actuation mechanism to discharge a volume of lubricant152through the input port140using the piston158. Other suitable mechanisms156may also be used to discharge the lubricant from the supply143.

In some embodiments, the separation between the O-rings110A and110B is selected such that they do not engage the input port140or the optional output port144during movement of the piston104relative to the cylinder110. Thus, with the input port140and/or the output port144centrally positioned relative to the range of motion108of the piston104along the axis107, the O-rings110A and110B are displaced from the input port140and/or the output port144a distance of greater than one-half the range of motion108.

In some embodiments, the reservoir130has a length160(FIG. 5) measured along the axis107that is greater than about 0.35 inch, such as greater than 0.50 inch, greater than 0.60 inch, and greater than 0.70 inch, such as 0.72 inch. The length160may also be based on the travel length or distance108(FIG. 1). In some embodiments, the length160is less than about 90% of the travel length108, such as about 60-90% of the travel length108, about 70-90% of the travel length108, and about 80-90% of the travel length108.

Additionally, the groove132has a maximum depth or distance161relative to the exterior surface of the piston104adjacent the O-rings110A and measured in a plane that is perpendicular to the axis107that is greater than about 0.060 inch, such as greater than about 0.70 inch, and greater than about 0.80 inch, such as about 0.085 inch. In some embodiments, the maximum depth161may be related to the maximum diameter162(FIG. 1) of the piston104. For example, the depth161may be greater than about 5% of the diameter162, such as, for example, about 5%, 10%, 15%, 20%, 25%, or 30% of the diameter162. For example, when the diameter162of the piston104is about 0.700 inch, the diameter of the piston104at the location of the maximum depth161may be about 0.530 inch.

In some embodiments, the exterior wall133of the piston104defining the reservoir130includes tapered ends163and164, which respectively taper toward the interior wall112of the cylinder110with distance toward ends165and166of the piston104. The tapered ends163and164respectively define tapered end portions168and169of the reservoir130. In some embodiments, the tapered ends163and164are oriented at an angle of about 10°-60° from the central axis107. The tapered ends163and164facilitate movement of lubricant toward the interior wall112of the cylinder106during movement of the piston104along the axis107, which aides in the lubrication of the O-rings110A and110B.

FIG. 6is a magnified side cross-sectional view of a portion of the piston104, the O-ring110A, and the cylinder106. In some embodiments, the exterior surface of the piston104surrounding the groove111A (shown) and111B, generally referred to as170, is positioned closer to the interior wall112of the cylinder than the exterior surface133of the piston104within the reservoir130. As a result, a gap between the interior wall112and the exterior surface170, which is measured in a plane that is perpendicular to the axis107and generally referred to as172, is less than a maximum gap173of the reservoir130between the interior wall112and the exterior surface133, as shown inFIG. 6. In some embodiments, the gap173is much greater than the gap172by about the maximum depth161(FIG. 5) of the groove132. In some embodiments, the gap172is less than about 50% of the gap173, such as less than about 40%, less than about 30%, less than about 20%, and/or less than about 10% of the maximum gap173, for example. In some embodiments, the gap172is about 0.002-0.015 inch.

In some embodiments, the piston104is formed to have an annular gap172A between the exterior surface170A of the piston104on a non-reservoir-side174of the O-ring110A, in which the groove111A is formed, and the interior surface112of the cylinder106. In some embodiments, the gap172A, which is measured in a plane that is perpendicular to the axis107, is approximately 0.002-0.010 inch, such as less than 0.005 inch and 0.004 inch or less. In some embodiments, the gap172A is greater than 6% of the diameter175of the O-ring110A when in an uncompressed state. The same or similar gap may also be provided on the piston104on the non-reservoir-side of the O-ring110B, in which the groove111B is formed.

In some embodiments, the piston104is formed to have an annular gap172B between an exterior surface170B of the piston104on a reservoir-side178of the O-ring110A, in which the groove111A is formed, and the interior surface112of the cylinder106. In some embodiments, the gap172B is larger than the gap172A, such as greater than 105% of the gap172A, greater than 110% of the gap172A, or greater than 120% of the gap172A, for example. In some embodiments, the gap172B is greater than 0.005 inch, such as greater than 0.010 inch, and 0.005-0.015 inch, for example. The reservoir-side178of the piston104adjacent the O-ring110B and the groove111B may also be formed to have the same or similar annular gap172B between the piston104and the interior surface112of the cylinder106.

The larger gap172B facilitates lubrication of the O-ring110A by increasing flow of the lubricant between the piston104and the interior wall112of the cylinder106on the reservoir-side178, while the smaller gap172A contains the lubricant between the O-rings110A and110B. The gap172B is still formed small enough to maintain retention of the O-ring110A within the groove111A during operation of the device100. In some embodiments, the larger gap172B is approximately 10-35% of the diameter175of the O-ring110A.

In some embodiments, the tapered ends163and164taper from the surface133at the maximum gap173from the interior wall112to the distance172, such as distance172A or172B. This is generally illustrated for the tapered end163inFIG. 6, and the same or similar configuration may be used for the tapered end164.

FIG. 7is a cross-sectional view of an exemplary piston104taken in a plane that is perpendicular to the axis107, in accordance with embodiments of the present disclosure. In some embodiments, notches180are formed in the exterior surface177of the piston104on the reservoir-side178of the O-ring110A adjacent the groove111A. The same or similar notches180may be formed in the exterior surface of the piston104on the reservoir-side of the O-ring110B adjacent the groove111B. In some embodiments, the notches180are angularly displaced from each other about the axis107, as shown inFIG. 7. The angular spacing between the notches180about the axis107may be less than 60°, or greater than 30°, such as 15°, 30°, 45° or 60°, for example.

The notches180increase the gap between the exterior surface177and interior wall112of the cylinder106to facilitate greater flow of the lubricant between the piston104and the interior wall112of the cylinder106on the reservoir-side178than would be possible if the notches180were not present. Thus, the notches180operate similarly to the larger gap172B (FIG. 6). In some embodiments, a gap182between an exterior surface184of the piston104within the notches180and the interior surface112of the cylinder106is larger than the gap172B formed between the exterior surface170B between the notches180of the piston104and the interior wall112of the cylinder106, such as illustrated inFIG. 6, in which a notch180is illustrated by a phantom line. In some embodiments, the gap182is greater than the gap172B, such as greater than 105%, such as greater than 110% of the gap172B, greater than 120% of the gap172B, greater than 130% of the gap172B, greater than 140% of the gap172B, and greater than 150% of the gap172B, for example. Exemplary dimensions for the gap182include greater than 0.010 inch, such as 0.010-0.020 inch, for example.

In some embodiments, the notches180may be used to enhance the lubricant flow to the O-ring110A provided by the larger gap172B. Thus, while the gap172B may be formed larger than the gap172A while the O-ring110A is retained within the groove111A, the notches180provide an even larger gap182without adversely affecting the O-ring retaining capability of the reservoir-side178of the groove111A. Alternatively, the gap172B may be the same or similar to the gap172A, while the notches180provide the desired pathway for the lubricant to flow to the O-ring110A. Here, the smaller gap172B may provide robust retention of the O-ring110A, while the notches180enhance lubrication of the O-ring110A.