Patent Description:
Linear fluid cylinders may have an in-cylinder position sensor having one or more magnets. However, the in-cylinder position sensor in conventional linear fluid cylinders may be susceptible to malfunction, damage, or failure. For instance, the magnets may be assembled into a rod bore assembly (used for holding a sensor rod) such that the magnets are damaged, such that the magnets are improperly installed (including forgotten), or such that the magnets displace from their intended location prior to assembly into the rod bore assembly (since the magnets may move freely). There is the additional possibility that the either the magnets or a metal retainer thereof contacts the sensor rod.

<CIT> ("the '<NUM> patent") describes a rotation angular sensor with a metal-injection molded magnet holder. According to the '<NUM> patent, to make it possible for a rotation angle sensor to be manufactured and assembled more easily and more accurately, the part components of a stator element made of a ferritic material are held in a sintered stator body by at least one holding element in a holding recess of a base element made of a non-magnetizable material. However, in that the '<NUM> patent describes a rotational angular sensor, the '<NUM> patent is not understood to describe a linear sensor.

Furthermore, <CIT> discloses a stroke sensor that detects a relative position of a piston with respect to a cylinder of a fluid pressure cylinder. The stroke sensor comprises a magnet to the piston and a sensor probe fixed to the cylinder.

<CIT> discloses an expanding contracting position detecting structure comprising a sensor rod guide consisting of a nonmagnetic body and being provided between an outer circumference of a sensor rod and an inner circumference of a protecting cylinder, and of a cylinder guide being provided between an outer circumference of the protecting cylinder and the inner circumference of a capacity chamber.

In accordance with the present invention, a hydraulic cylinder as set forth in claim <NUM> and a method as set forth in claim <NUM> is provided. Preferred embodiments of the invention are claimed in the dependent claims.

Other features and aspects of this invention will be apparent from the following description and the accompanying drawings.

The present invention relates to linear fluid cylinders, and more particularly to linear fluid cylinders having an internally-mounted linear cylinder position sensor retainer assembly and systems, assemblies, components, and methods thereof.

<FIG> is a sectional view of a fluid cylinder <NUM> according to one or more embodiments of the disclosed subject matter. The fluid cylinder <NUM> is hydraulic.

The fluid cylinder <NUM> includes a body <NUM>. The body <NUM> is elongate such as shown in <FIG> and defines an internal cavity <NUM>. According to one or more embodiments, the body <NUM> and the internal cavity <NUM> can be cylindrical. A longitudinal axis <NUM> extends through the body <NUM> and the internal cavity <NUM>. A first end cap <NUM> and a second end cap <NUM> are provided at opposite ends of the body <NUM>. A piston and rod assembly <NUM>, which is movable in a direction of the longitudinal axis <NUM>, is disposed at least partially in the internal cavity <NUM>, such as shown in <FIG>. The piston and rod assembly <NUM> can include a rod <NUM> having a first end connected to a piston <NUM>, such as shown in <FIG>. A second end of the rod <NUM> can extend from the second end cap <NUM>. It is noted that embodiments of the disclosed subject matter are not limited to the specific piston and rod assembly <NUM> shown in <FIG>. For instance, embodiments of the disclosed subject matter can include a piston and rod assembly <NUM> having a rod <NUM> with a counterbore <NUM> at an end thereof.

A position sensor assembly <NUM> is provided in the fluid cylinder <NUM>. In that the position sensor assembly <NUM> is provided in the fluid cylinder <NUM>, the position sensor assembly <NUM> may be referred to as an in-cylinder position sensor assembly. The position sensor assembly <NUM> includes a sensor <NUM> and a sensor rod <NUM>. According to some embodiments, the sensor rod <NUM> may be referred to as a pressure pipe. As shown in <FIG>, the sensor rod <NUM> extends in the internal cavity <NUM> along the longitudinal axis <NUM> and, moreover, is cooperatively telescopically received within an axial passage of the rod <NUM>.

Generally, the sensor <NUM> can be a magnetostrictive type sensor and the position sensor assembly <NUM> can be adapted to determine position of the piston and rod assembly <NUM>. In this regard, the sensor rod <NUM> can include a magnetorestrictive element or waveguide that can interact with one or more magnets (e.g., angular magnet(s)) associated with the piston and rod assembly <NUM> (discussed in more detail below). However, embodiments of the disclosed subject matter are not limited to magnetorestrictive sensors and may include another type of linear sensor, such as a Hall effect sensor.

The fluid cylinder <NUM> also includes a retainer assembly <NUM> according to embodiments of the present invention in the internal cavity <NUM>. As shown in <FIG>, the retainer assembly <NUM> interfaces with the piston and rod assembly <NUM> and the sensor rod <NUM>. More specifically, the retainer assembly <NUM> is coaxial with the sensor rod <NUM> whereby the sensor rod <NUM> extends through the retainer assembly <NUM> and projects from both ends of the retainer assembly <NUM>. Discussed in more detail below, at least a portion of the retainer assembly <NUM> can contact the sensor rod <NUM> and provides support for the sensor rod <NUM> in at least the radial direction. Thus, the retainer assembly <NUM> retains the sensor rod <NUM> at the longitudinal axis <NUM>.

Turning now to <FIG>, the retainer assembly <NUM> is comprised of a body <NUM>, a sleeve <NUM>, and one or more magnets <NUM>. According to one or more embodiments, the body <NUM>, the sleeve <NUM>, and the one or more magnets <NUM> may be the only components of the retainer assembly <NUM>. Thus, the retainer assembly <NUM> consists of the body <NUM>, the sleeve <NUM>, and the one or more magnets <NUM>.

The body <NUM> can be annular and defines a bore <NUM> that extends from a first end <NUM> of the body <NUM> to a second end <NUM> of the body <NUM>. The bore <NUM> is defined by an inner wall <NUM> of the body <NUM> opposite an outer wall <NUM> of the body <NUM>. The bore <NUM><NUM>. is adapted to receive the sensor rod <NUM>, such as shown in <FIG> discussed above, whereby the sensor rod <NUM> extends from the first end <NUM> and the second end <NUM> of the body <NUM>. According to one or more embodiments, the body <NUM> can be made of any non-ferromagnetic material, such as brass, aluminum, stainless steel, plastic, composite, etc. According to one or more embodiments, plain carbon steel or cast iron may not be used as a material for the body <NUM>, unless the one or more magnets <NUM> are prevented from direct contact with the body <NUM>.

The body <NUM> can be considered to have a first body portion <NUM> and a second body portion <NUM>. The first body portion <NUM> and the second body portion <NUM> can be associated with (and indeed include) the first end <NUM> and the second end <NUM> of the body <NUM>, respectively.

As shown in <FIG>, the bore <NUM> can have a greater cross-sectional area or diameter, as defined by the inner wall <NUM>, at the first end <NUM> as compared to the second end <NUM>. Also shown in <FIG>, the inner wall <NUM> can taper at an angle θ relative to the longitudinal axis <NUM> (e.g., at or about sixty degrees combined for opposite sides of the inner wall <NUM>). Such tapering can facilitate passage of the sensor rod <NUM> through the retainer assembly <NUM>. An inner diameter of the inner wall <NUM> may be constant from the second end <NUM> for a predetermined length. Such length can be the same length as that of the sleeve <NUM>. According to one or more embodiments, the inner wall <NUM> at the first end <NUM> of the body <NUM> can be in the form of a hexagon (or some other polygon) when viewed from the first end <NUM> of the body <NUM>. The shape of the inner wall <NUM> at the first end <NUM> can match a torque tool (e.g., a hex key) to assemble the body <NUM> to the corresponding piston and rod assembly <NUM>, <NUM>.

Additionally or alternatively, an outer diameter of the body <NUM>, as defined by the outer wall <NUM>, can be greater at a first end portion of the body <NUM> associated with the first end <NUM> of the body <NUM> as compared to an outer diameter of the body <NUM>, as defined by the outer wall <NUM>, at a second end portion of the body <NUM> associated with the second end <NUM> of the body <NUM>. According to one or more embodiments, the outer diameter of the outer wall <NUM> for the first body portion <NUM> can be constant and the outer diameter of the outer wall <NUM> for the second body portion <NUM> can vary, such as according to the plateau and valleys shown in <FIG>. The relief features of the outer wall <NUM> at the second body portion <NUM> can be to reliably and effectively interface with the piston and rod assembly <NUM>. Depending upon whether the first body portion <NUM> is exposed (as in <FIG>) or unexposed (e.g., inside the counterbore <NUM> at the end of the rod <NUM> as in <FIG>), some or all of the outer wall <NUM> can be threaded to interface with the corresponding piston and rod assembly <NUM>, <NUM>. For instance, when the first body portion <NUM> is exposed the outer wall <NUM> at the first body portion <NUM> may not have threads and some or all of the outer wall <NUM> at the second body portion <NUM> may be threaded. On the other hand, when the first body portion <NUM> is not exposed, threads may be provided in the outer wall <NUM> at the first body portion <NUM> and/or at the second body portion <NUM>.

The sleeve <NUM> can be annular or in the form of a ring and can be made of a non-metal or non-metallic durable material or composite. The material/composite can be particularly resistant to wear against metal without abrading and/or generating hard particles. For instance, the sleeve <NUM> can be made of nylon (polyamide) filled with an additive, such as glass. Of course, embodiments of the disclosed subject matter are not limited to the foregoing materials for the sleeve <NUM>. Alternatively, the sleeve <NUM> can be polytetrafluoroethylene (PTFE) filled/unfilled material. The sleeve <NUM> is disposed in the bore <NUM> of the body <NUM> at a portion of the inner wall <NUM> such as shown in <FIG>. Thus, the sleeve <NUM> is radially outward of the sensor rod <NUM>, such as shown in <FIG>. More specifically, the inner wall <NUM> of the sleeve <NUM> can contact the sensor rod <NUM>. In this regard, the sleeve <NUM> can protect the sensor rod <NUM> as the sensor rod <NUM> travels along the longitudinal axis <NUM> during operation of the fluid cylinder <NUM>.

The length of the sleeve <NUM> can be less than the length of the body <NUM>. According to one or more embodiments, no portion of the sleeve <NUM> extends from either the first end <NUM> or the second end <NUM> of the body <NUM>. Such extending may also mean that an inner-most diameter of the sleeve <NUM>, as defined by the inner wall <NUM> of the sleeve <NUM>, is not less than an inner-most diameter of the inner wall <NUM> of the body <NUM>. According to one or more embodiments, the inner wall <NUM> of the sleeve <NUM> can have a constant diameter. In some respects, the inner wall <NUM> of the sleeve <NUM>, when fitted in the bore <NUM> of the body <NUM>, can effectively form an inner wall that defines that portion of the bore <NUM>.

Each of the one or more magnets <NUM> can be an angular magnet and is disposed radially outward of at least a portion of an outer wall <NUM> of the sleeve <NUM>. Thus, each of the one or more magnets <NUM> is disposed between the sleeve <NUM> and the body <NUM>, at least in a radial direction of the body <NUM>. In this regard, the one or more magnets <NUM> are provided also radially outward of the sensor rod <NUM>. However, as shown in <FIG>, no portion of the one or more magnets <NUM> may be exposed from the body <NUM> or the sleeve <NUM>. Thus, no portion of the one or more magnets <NUM> can contact the sensor rod <NUM> as the sensor rod <NUM> moves along the longitudinal axis during operation of the fluid cylinder <NUM>. Optionally, the one or more magnets <NUM> can be provided in a cutout (or cutouts) <NUM> of the sleeve <NUM>, such as shown in <FIG>.

At least a portion of the outer wall <NUM> of the sleeve <NUM> can be fixed to the inner wall <NUM> of the body <NUM>. According to embodiments of the disclosed subject matter, the outer wall <NUM> of the sleeve <NUM> can be fixed to the inner wall <NUM> via friction fit, snap fit, or threading. The sleeve <NUM> in <FIG>, for instance, can be inserted in the bore <NUM> such that the outer wall <NUM> frictionally engages with the inner wall <NUM> of the body <NUM>.

Each of the one or more magnets <NUM> is fixedly disposed between the sleeve <NUM> and the body <NUM>. For instance, at the very least the sleeve <NUM> retained in the bore <NUM> can retain the one or more magnets <NUM> in position. Hence, according to one or more embodiments, the sleeve <NUM> is also referred to as a magnet ring. The one or more magnets <NUM> are also molded between the body <NUM> and the sleeve <NUM>. According to embodiments of the disclosed subject matter, the one or more magnets <NUM> can be so-called in-molded to the inner wall <NUM> of the body <NUM> or can be so-called out-molded to the outer wall <NUM> of the sleeve <NUM>. Such molding can occur prior to inserting the sleeve <NUM> into the bore <NUM> to fixedly attach the sleeve <NUM> to the body <NUM>.

<FIG> is a sectional view of a fluid cylinder <NUM> according to one or more embodiments of the disclosed subject matter. Fluid cylinder <NUM> is similar to the fluid cylinder <NUM> discussed above for <FIG>, but notably implements another retainer assembly <NUM> according to embodiments of the disclosed subject matter. <FIG> shows an enlarged portion of <FIG>, and <FIG> shows a sectional view of the retainer assembly <NUM>.

The retainer assembly <NUM> is comprised of a body <NUM>, a sleeve <NUM>, and one or more magnets <NUM>. According to one or more embodiments, the body <NUM>, the sleeve <NUM>, and the one or more magnets <NUM> may be the only components of the retainer assembly <NUM>. Thus, the retainer assembly <NUM> consists of the body <NUM>, the sleeve <NUM>, and the one or more magnets <NUM>.

The body <NUM> can be annular and defines a bore <NUM> that extends from a first end <NUM> of the body <NUM> to a second end <NUM> of the body <NUM>. The bore <NUM> is defined by an inner wall <NUM> of the body <NUM> opposite an outer wall <NUM> of the body <NUM>. The bore <NUM> is adapted to receive the sensor rod <NUM>, such as shown in <FIG> and <FIG>, whereby the sensor rod <NUM> extends from the first end <NUM> and the second end <NUM> of the body <NUM>. According to one or more embodiments, the body <NUM> can be made of any non-ferromagnetic material, such as brass, aluminum, stainless steel, plastic, composite, etc. According to one or more embodiments, plain carbon steel or cast iron may not be used as a material for the body <NUM>, unless the one or more magnets <NUM> are prevented from direct contact with the body <NUM>.

As shown in <FIG>, the bore <NUM> can have a greater cross-sectional area or diameter, as defined by the inner wall <NUM>, at the first end <NUM> as compared to the second end <NUM>. According to one or more embodiments, the inner wall <NUM> at the first end <NUM> of the body <NUM> can be in the form of a hexagon (or some other polygon) when viewed from the first end <NUM> of the body <NUM>. The shape of the inner wall <NUM> at the first end <NUM> can match a torque tool (e.g., a hex key) to assemble the body <NUM> to the corresponding piston and rod assembly <NUM>, <NUM>.

Additionally or alternatively, an outer diameter of the body <NUM>, as defined by the outer wall <NUM>, can be greater at a first end portion of the body <NUM> associated with the first end <NUM> of the body <NUM> as compared to an outer diameter of the body <NUM>, as defined by the outer wall <NUM>, at a second end portion of the body <NUM> associated with the second end <NUM> of the body <NUM>. According to one or more embodiments, the outer diameter of the outer wall <NUM> for the first body portion <NUM> can be constant and the outer diameter of the outer wall <NUM> for the second body portion <NUM> can vary, such as according to the plateau and valleys shown in <FIG>. The relief features of the outer wall <NUM> at the second body portion <NUM> can be to reliably and effectively interface with the piston and rod assembly <NUM>. Depending upon whether the first body portion <NUM> is exposed (as in <FIG> and <FIG>) or unexposed (e.g., inside the counterbore <NUM> at the end of the rod <NUM> as in <FIG>), some or all of the outer wall <NUM> can be threaded to interface with the corresponding piston and rod assembly <NUM>, <NUM>. For instance, when the first body portion <NUM> is exposed the outer wall <NUM> at the first body portion <NUM> may not have threads and some or all of the outer wall <NUM> at the second body portion <NUM> may be threaded. On the other hand, when the first body portion <NUM> is not exposed, threads may be provided in the outer wall <NUM> at the first body portion <NUM> and/or at the second body portion <NUM>.

The sleeve <NUM> can be annular or in the form of a ring and can be made of a non-metal or non-metallic durable material or composite. The material/composite can be particularly resistant to wear against metal without abrading and/or generating hard particles. For instance, the sleeve <NUM> can be made of nylon (polyamide) filled with an additive, such as glass. Alternatively, the sleeve <NUM> can be polytetrafluoroethylene (PTFE) filled/unfilled material. Of course, embodiments of the disclosed subject matter are not limited to the foregoing materials for the sleeve <NUM>. The sleeve <NUM> is disposed in the bore <NUM> of the body <NUM> at a portion of the inner wall <NUM> such as shown in <FIG>. Thus, the sleeve <NUM> is radially outward of the sensor rod <NUM>, such as shown in <FIG> and <FIG>. More specifically, the inner wall <NUM> of the sleeve <NUM> can contact the sensor rod <NUM>. In this regard, the sleeve <NUM> can protect the sensor rod <NUM> as the sensor rod <NUM> travels along the longitudinal axis <NUM> during operation of the fluid cylinder <NUM>.

The length of the sleeve <NUM> can be less than the length of the body <NUM>. According to one or more embodiments, no portion of the sleeve <NUM> may extend from either the first end <NUM> or the second end <NUM> of the body <NUM>. Note, however, that in this example, the length of the sleeve <NUM> can be longer than that of the sleeve <NUM> for <FIG>. For instance, the sleeve <NUM> can extend from the second end <NUM> of the body <NUM> into the first body portion <NUM> of the body <NUM>.

Such extending may also mean that an inner-most diameter of the sleeve <NUM>, as defined by the inner wall <NUM> of the sleeve <NUM>, is less than an inner-most diameter of the inner wall <NUM> of the body <NUM>. In this example, the inner wall <NUM> of the sleeve <NUM> can have an internal diameter less than any internal diameter defined by the inner wall <NUM> of the body <NUM>.

According to one or more embodiments, the inner wall <NUM> of the sleeve <NUM> can have a substantially constant diameter, at least from the second end <NUM> of the body <NUM>. However, in this example, an end of the sleeve <NUM> opposite the second end <NUM> of the body <NUM> can be tapered at an angle θ relative to the longitudinal axis <NUM> (e.g., at or about sixty degrees combined for opposite sides of the inner wall <NUM>). Such tapering can facilitate passage of the sensor rod <NUM> through the retainer assembly <NUM>.

Each of the one or more magnets <NUM> can be an angular magnet and is disposed radially outward of at least a portion of an outer wall <NUM> of the sleeve <NUM>. Thus, each of the one or more magnets <NUM> is disposed between the sleeve <NUM> and the body <NUM>, at least in a radial direction of the body <NUM>. In this regard, the one or more magnets <NUM> are provided also radially outward of the sensor rod <NUM>. However, as shown in <FIG>, no portion of the one or more magnets <NUM> can be exposed from the body <NUM> or the sleeve <NUM>. Thus, no portion of the one or more magnets <NUM> can contact the sensor rod <NUM>. Optionally, the one or more magnets <NUM> can be provided in a cutout (or cutouts) <NUM> of the sleeve <NUM>, such as shown in <FIG>.

At least a portion of the outer wall <NUM> of the sleeve <NUM> can be fixed to the inner wall <NUM> of the body <NUM>. According to embodiments of the disclosed subject matter, the outer wall <NUM> of the sleeve <NUM> can be fixed to the inner wall <NUM> via friction fit, snap fit, or threading. The sleeve <NUM> in <FIG>, for instance, can be inserted in the bore <NUM> such that elevations (e.g., ridges or projections) in the outer wall <NUM> snap fit with corresponding recesses in the inner wall <NUM> of the body <NUM>.

Each of the one or more magnets <NUM> are fixedly disposed between the sleeve <NUM> and the body <NUM>. For instance, at the very least the sleeve <NUM> retained in the bore <NUM> can retain the one or more magnets <NUM> in position. The one or more magnets <NUM> are also molded between the body <NUM> and the sleeve <NUM>. According to embodiments of the disclosed subject matter, the one or more magnets <NUM> can be so-called in-molded to the inner wall <NUM> of the body <NUM> or can be so-called out-molded to the outer wall <NUM> of the sleeve <NUM>. Such molding can occur prior to inserting the sleeve <NUM> into the bore <NUM> to fixedly attach the sleeve <NUM> to the body <NUM>.

<FIG> shows a sectional view of another retainer assembly <NUM>. The retainer assembly <NUM> is comprised of a body <NUM>, a sleeve <NUM>, and one or more magnets <NUM>. According to one or more embodiments, the body <NUM>, the sleeve <NUM>, and the one or more magnets <NUM> may be the only components of the retainer assembly <NUM>. Thus, the retainer assembly <NUM> consists of the body <NUM>, the sleeve <NUM>, and the one or more magnets <NUM>.

The body <NUM> can be annular and defines a bore <NUM> that extends from a first end <NUM> of the body <NUM> to a second end <NUM> of the body <NUM>. The bore <NUM> is defined by an inner wall <NUM> of the body <NUM> opposite an outer wall <NUM> of the body <NUM>. The bore <NUM> is adapted to receive the sensor rod <NUM>, such as shown above, whereby the sensor rod <NUM> extends from the first end <NUM> and the second end <NUM> of the body <NUM>. According to one or more embodiments, the body <NUM> can be made of any non-ferromagnetic material, such as brass, aluminum, stainless steel, plastic, composite, etc. According to one or more embodiments, plain carbon steel or cast iron may not be used as a material for the body <NUM>, unless the one or more magnets <NUM> are prevented from direct contact with the body <NUM>.

Additionally or alternatively, an outer diameter of the body <NUM>, as defined by the outer wall <NUM>, can be greater at a first end portion of the body <NUM> associated with the first end <NUM> of the body <NUM> as compared to an outer diameter of the body <NUM>, as defined by the outer wall <NUM>, at a second end portion of the body <NUM> associated with the second end <NUM> of the body <NUM>. According to one or more embodiments, the outer diameter of the outer wall <NUM> for the first body portion <NUM> can be constant and the outer diameter of the outer wall <NUM> for the second body portion <NUM> can vary, such as according to the plateau and valleys shown in <FIG>. The relief features of the outer wall <NUM> at the second body portion <NUM> can be to reliably and effectively interface with the piston and rod assembly <NUM>. Depending upon whether the first body portion <NUM> is exposed (e.g., as in <FIG> or <FIG>) or unexposed (e.g., inside the counterbore <NUM> at the end of the rod <NUM> as in <FIG>), some or all of the outer wall <NUM> can be threaded to interface with the corresponding piston and rod assembly <NUM>, <NUM>. For instance, when the first body portion <NUM> is exposed the outer wall <NUM> at the first body portion <NUM> may not have threads and some or all of the outer wall <NUM> at the second body portion <NUM> may be threaded. On the other hand, when the first body portion <NUM> is not exposed, threads may be provided in the outer wall <NUM> at the first body portion <NUM> and/or at the second body portion <NUM>.

The sleeve <NUM> can be annular or in the form of a ring and can be made of a non-metal or non-metallic durable material or composite. The material/composite can be particularly resistant to wear against metal without abrading and/or generating hard particles. For instance, the sleeve <NUM> can be made of nylon (polyamide) filled with an additive, such as glass. Alternatively, the sleeve <NUM> can be polytetrafluoroethylene (PTFE) filled/unfilled material. Of course, embodiments of the disclosed subject matter are not limited to the foregoing materials for the sleeve <NUM>. The sleeve <NUM> is disposed in the bore <NUM> of the body <NUM> at a portion of the inner wall <NUM> such as shown in <FIG>. Thus, the sleeve <NUM> is radially outward of the sensor rod <NUM>, such as discussed above. More specifically, the inner wall <NUM> of the sleeve <NUM> can contact the sensor rod <NUM>. In this regard, the sleeve <NUM> can protect the sensor rod <NUM> as the sensor rod <NUM> travels along the longitudinal axis <NUM> during operation of the fluid cylinder <NUM>.

Such extending may also mean that an inner-most diameter of the sleeve <NUM>, as defined by the inner wall <NUM> of the sleeve <NUM>, is less than an inner-most diameter of the inner wall <NUM> of the body <NUM>. In this example, the inner wall <NUM> of the sleeve <NUM> can have an inner diameter less than any inner diameter defined by the inner wall <NUM> of the body <NUM>.

According to one or more embodiments, the inner wall <NUM> of the sleeve <NUM> can have a substantially constant diameter, at least from the second end <NUM> of the body <NUM>. However, in this example, an end of the sleeve <NUM> opposite the second end <NUM> of the body <NUM> can be tapered at an angle θ relative to the longitudinal axis <NUM> (e.g., at or about sixty degrees combined for opposite sides of the inner wall <NUM>). In this example, the inner wall <NUM> of the body <NUM> can also be tapered relative to the longitudinal axis <NUM>. Optionally, the angles of taper for the inner wall <NUM> of the sleeve <NUM> and the inner wall <NUM> of the body <NUM> can be the same angle θ (e.g., at or about sixty degrees combined for opposite sides). Such tapering can facilitate passage of the sensor rod <NUM> through the retainer assembly <NUM>.

At least a portion of the outer wall <NUM> of the sleeve <NUM> can be fixed to the inner wall <NUM> of the body <NUM>. According to embodiments of the disclosed subject matter, the outer wall <NUM> of the sleeve <NUM> can be fixed to the inner wall <NUM> via friction fit, snap fit, or threading. As shown in <FIG>, the inner wall <NUM> of the body <NUM> can have a plurality of sets of one or more grooves adapted to interface with corresponding projects on the outer wall <NUM> of the sleeve <NUM>. Such features can be provided to limit or prevent any movement of the molded in materials once molded. Otherwise, the material (e.g., polymer) may slide axially.

Each of the one or more magnets <NUM> is fixedly disposed between the sleeve <NUM> and the body <NUM>. For instance, at the very least the sleeve <NUM> retained in the bore <NUM> can retain the one or more magnets <NUM> in position. The one or more magnets <NUM> are also molded between the body <NUM> and the sleeve <NUM>. According to embodiments of the disclosed subject matter, the one or more magnets <NUM> can be so-called in-molded to the inner wall <NUM> of the body <NUM> or can be so-called out-molded to the outer wall <NUM> of the sleeve <NUM>. Such molding can occur prior to inserting the sleeve <NUM> into the bore <NUM> to fixedly attach the sleeve <NUM> to the body <NUM>.

As noted above, the present invention relates to linear fluid cylinders, and more particularly to linear fluid cylinders having an internally-mounted linear cylinder position sensor retainer assembly and systems, assemblies, components, and methods thereof.

Retainer assemblies according to embodiments of the disclosed subject matter, such as retainer assemblies <NUM>, <NUM>, <NUM> discussed above, are adapted to interface with a sensor rod of an in-cylinder position sensor assembly of a fluid cylinder, such as position sensor assembly <NUM> in fluid cylinder <NUM> discussed above. Retainer assemblies according to embodiments of the disclosed subject matter retain one or more magnets between a body and a sleeve of the retainer assembly, such as one or more magnets <NUM>, <NUM>, <NUM> between body <NUM>, <NUM>, <NUM> and sleeve <NUM>, <NUM>, <NUM>. The one or more magnets can be injection molded in place according to one or more embodiments. Thus, the one or more magnets can be retained in position prior to and after assembly of the retainer assembly.

Moreover, the one or more magnets can be insulated by at least the sleeve. Hence, the one or more magnets may not contact the sensor rod of the position sensor assembly, since the sleeve can intervene between the one or more magnets and the sensor rod. In that at least the sleeve can be made of the non-metal or non-metallic material and can be provided between the one or more magnets and the sensor rod, metal-to-metal contact between the sensor rod and another metal or metallic component, such as the one or more magnets, can be prevented.

Claim 1:
A hydraulic cylinder (<NUM>) comprising:
an elongate body (<NUM>) defining an internal cavity (<NUM>) that extends along a longitudinal axis (<NUM>) of the elongate body (<NUM>);
a pair of end caps (<NUM>, <NUM>) at opposite ends of the elongate body (<NUM>);
a piston and rod assembly (<NUM>, <NUM>) at least partially in the internal cavity (<NUM>), the piston and rod assembly (<NUM>, <NUM>) being movable in a direction of the longitudinal axis (<NUM>);
a position sensor (<NUM>) and a sensor rod (<NUM>) in the internal cavity (<NUM>), the sensor rod (<NUM>) extending along the longitudinal axis (<NUM>); and
a sensor retainer assembly (<NUM>, <NUM>, <NUM>) in the internal cavity (<NUM>), the sensor retainer assembly (<NUM>, <NUM>, <NUM>) being coaxial with the sensor rod (<NUM>) and adapted to retain the sensor rod (<NUM>) at the longitudinal axis (<NUM>), the sensor retainer assembly (<NUM>, <NUM>, <NUM>) including:
an annular body (<NUM>, <NUM>, <NUM>) defining a bore (<NUM>, <NUM>, <NUM>) extending from opposite ends of the annular body (<NUM>, <NUM>, <NUM>), the bore (<NUM>, <NUM>, <NUM>) being adapted to receive the sensor rod (<NUM>) such that the sensor rod (<NUM>) extends from the opposite ends of the annular body (<NUM>, <NUM>, <NUM>),
a magnet ring (<NUM>, <NUM>, <NUM>) disposed in the bore (<NUM>, <NUM>, <NUM>) at an inner wall (<NUM>, <NUM>, <NUM>) of the annular body (<NUM>, <NUM>, <NUM>), the magnet ring (<NUM>, <NUM>, <NUM>) being radially outward of the sensor rod (<NUM>), and
one or more magnets (<NUM>, <NUM>, <NUM>) fixedly disposed between the annular body (<NUM>, <NUM>, <NUM>) and the magnet ring (<NUM>, <NUM>, <NUM>) in a radial direction of the annular body (<NUM>, <NUM>, <NUM>), the one or more magnets (<NUM>, <NUM>, <NUM>) being radially outward of the sensor rod (<NUM>),
wherein each of the one or more magnets (<NUM>, <NUM>, <NUM>) is fixedly molded between the annular body (<NUM>, <NUM>, <NUM>) and the magnet ring (<NUM>, <NUM>, <NUM>).