Arrangements, components and methods for forming magnetic sensors and systems

Description

Technical Field

[0001] 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.Background

[0002] 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.

[0003] US 6 194 894 B1 ("the '894 patent") describes a rotation angular sensor with a metal-injection molded magnet holder. According to the '894 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 '894 patent describes a rotational angular sensor, the '894 patent is not understood to describe a linear sensor.

[0004] Furthermore, EP 1 867 880 A1 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.

[0005] JP H11 190308 A 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.Summary

[0006] In accordance with the present invention, a hydraulic cylinder as set forth in claim 1 and a method as set forth in claim 6 is provided. Preferred embodiments of the invention are claimed in the dependent claims.

[0007] Other features and aspects of this invention will be apparent from the following description and the accompanying drawings.Brief Description of Drawings

[0008] FIG. 1 is a sectional view of a fluid cylinder according to one or more embodiments of the disclosed subject matter. FIG. 2 is an enlarged view of a portion of the fluid cylinder of FIG. 1. FIG. 3 is a sectional view of a fluid cylinder according to one or more embodiments of the disclosed subject matter. FIG. 4 is a sectional view of a retainer assembly of the fluid cylinder of FIG. 3, according to one or more embodiments of the disclosed subject matter. FIG. 5 is an enlarged sectional view of a retainer assembly of the fluid cylinder of FIG. 4, according to one or more embodiments of the disclosed subject matter. FIG. 6 shows a sectional view of another retainer assembly according to one or more embodiments of the disclosed subject matter. FIG. 7 shows a sectional view of a portion of a fluid cylinder according to one or more embodiments of the disclosed subject matter. Detailed Description

[0009] 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.

[0010] FIG. 1 is a sectional view of a fluid cylinder 10 according to one or more embodiments of the disclosed subject matter. The fluid cylinder 10 is hydraulic.

[0011] The fluid cylinder 10 includes a body 12. The body 12 is elongate such as shown in FIG. 1 and defines an internal cavity 14. According to one or more embodiments, the body 12 and the internal cavity 14 can be cylindrical. A longitudinal axis 16 extends through the body 12 and the internal cavity 14. A first end cap 26 and a second end cap 28 are provided at opposite ends of the body 12. A piston and rod assembly 18, which is movable in a direction of the longitudinal axis 16, is disposed at least partially in the internal cavity 14, such as shown in FIG. 1. The piston and rod assembly 18 can include a rod 20 having a first end connected to a piston 24, such as shown in FIG. 1. A second end of the rod 20 can extend from the second end cap 28. It is noted that embodiments of the disclosed subject matter are not limited to the specific piston and rod assembly 18 shown in FIG. 1. For instance, embodiments of the disclosed subject matter can include a piston and rod assembly 19 having a rod 21 with a counterbore 22 at an end thereof.

[0012] A position sensor assembly 30 is provided in the fluid cylinder 10. In that the position sensor assembly 30 is provided in the fluid cylinder 10, the position sensor assembly 30 may be referred to as an in-cylinder position sensor assembly. The position sensor assembly 30 includes a sensor 32 and a sensor rod 35. According to some embodiments, the sensor rod 35 may be referred to as a pressure pipe. As shown in FIG. 1, the sensor rod 35 extends in the internal cavity 14 along the longitudinal axis 16 and, moreover, is cooperatively telescopically received within an axial passage of the rod 20.

[0013] Generally, the sensor 32 can be a magnetostrictive type sensor and the position sensor assembly 30 can be adapted to determine position of the piston and rod assembly 18. In this regard, the sensor rod 35 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 18 (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.

[0014] The fluid cylinder 10 also includes a retainer assembly 50 according to embodiments of the present invention in the internal cavity 14. As shown in FIG. 1, the retainer assembly 50 interfaces with the piston and rod assembly 18 and the sensor rod 35. More specifically, the retainer assembly 50 is coaxial with the sensor rod 35 whereby the sensor rod 35 extends through the retainer assembly 50 and projects from both ends of the retainer assembly 50. Discussed in more detail below, at least a portion of the retainer assembly 50 can contact the sensor rod 35 and provides support for the sensor rod 35 in at least the radial direction. Thus, the retainer assembly 50 retains the sensor rod 35 at the longitudinal axis 16.

[0015] Turning now to FIG. 2, the retainer assembly 50 is comprised of a body 60, a sleeve 70, and one or more magnets 80. According to one or more embodiments, the body 60, the sleeve 70, and the one or more magnets 80 may be the only components of the retainer assembly 50. Thus, the retainer assembly 50 consists of the body 60, the sleeve 70, and the one or more magnets 80.

[0016] The body 60 can be annular and defines a bore 61 that extends from a first end 62 of the body 60 to a second end 63 of the body 60. The bore 61 is defined by an inner wall 64 of the body 60 opposite an outer wall 65 of the body 60. The bore 61 2. is adapted to receive the sensor rod 35, such as shown in FIG. 1 discussed above, whereby the sensor rod 35 extends from the first end 62 and the second end 63 of the body 60. According to one or more embodiments, the body 60 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 60, unless the one or more magnets 80 are prevented from direct contact with the body 60.

[0017] The body 60 can be considered to have a first body portion 68 and a second body portion 69. The first body portion 68 and the second body portion 69 can be associated with (and indeed include) the first end 62 and the second end 63 of the body 60, respectively.

[0018] As shown in FIG. 2, the bore 61 can have a greater cross-sectional area or diameter, as defined by the inner wall 64, at the first end 62 as compared to the second end 63. Also shown in FIG. 2, the inner wall 64 can taper at an angle θ relative to the longitudinal axis 16 (e.g., at or about sixty degrees combined for opposite sides of the inner wall 64). Such tapering can facilitate passage of the sensor rod 35 through the retainer assembly 50. An inner diameter of the inner wall 64 may be constant from the second end 63 for a predetermined length. Such length can be the same length as that of the sleeve 70. According to one or more embodiments, the inner wall 64 at the first end 62 of the body 60 can be in the form of a hexagon (or some other polygon) when viewed from the first end 62 of the body 60. The shape of the inner wall 64 at the first end 62 can match a torque tool (e.g., a hex key) to assemble the body 60 to the corresponding piston and rod assembly 18, 19.

[0019] Additionally or alternatively, an outer diameter of the body 60, as defined by the outer wall 65, can be greater at a first end portion of the body 60 associated with the first end 62 of the body 60 as compared to an outer diameter of the body 60, as defined by the outer wall 65, at a second end portion of the body 60 associated with the second end 63 of the body 60. According to one or more embodiments, the outer diameter of the outer wall 65 for the first body portion 68 can be constant and the outer diameter of the outer wall 65 for the second body portion 69 can vary, such as according to the plateau and valleys shown in FIG. 2. The relief features of the outer wall 65 at the second body portion 69 can be to reliably and effectively interface with the piston and rod assembly 18. Depending upon whether the first body portion 68 is exposed (as in FIG. 1) or unexposed (e.g., inside the counterbore 22 at the end of the rod 21 as in FIG. 7), some or all of the outer wall 65 can be threaded to interface with the corresponding piston and rod assembly 18, 19. For instance, when the first body portion 68 is exposed the outer wall 65 at the first body portion 68 may not have threads and some or all of the outer wall 65 at the second body portion 69 may be threaded. On the other hand, when the first body portion 68 is not exposed, threads may be provided in the outer wall 65 at the first body portion 68 and / or at the second body portion 69.

[0020] The sleeve 70 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 70 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 170. Alternatively, the sleeve 70 can be polytetrafluoroethylene (PTFE) filled / unfilled material. The sleeve 70 is disposed in the bore 61 of the body 60 at a portion of the inner wall 64 such as shown in FIG. 2. Thus, the sleeve 70 is radially outward of the sensor rod 35, such as shown in FIG. 1. More specifically, the inner wall 74 of the sleeve 70 can contact the sensor rod 35. In this regard, the sleeve 70 can protect the sensor rod 35 as the sensor rod 35 travels along the longitudinal axis 16 during operation of the fluid cylinder 10.

[0021] The length of the sleeve 70 can be less than the length of the body 60. According to one or more embodiments, no portion of the sleeve 70 extends from either the first end 62 or the second end 63 of the body 60. Such extending may also mean that an inner-most diameter of the sleeve 70, as defined by the inner wall 74 of the sleeve 70, is not less than an inner-most diameter of the inner wall 64 of the body 60. According to one or more embodiments, the inner wall 74 of the sleeve 70 can have a constant diameter. In some respects, the inner wall 74 of the sleeve 70, when fitted in the bore 61 of the body 60, can effectively form an inner wall that defines that portion of the bore 61.

[0022] Each of the one or more magnets 80 can be an angular magnet and is disposed radially outward of at least a portion of an outer wall 75 of the sleeve 70. Thus, each of the one or more magnets 80 is disposed between the sleeve 70 and the body 60, at least in a radial direction of the body 60. In this regard, the one or more magnets 80 are provided also radially outward of the sensor rod 35. However, as shown in FIG. 2, no portion of the one or more magnets 80 may be exposed from the body 60 or the sleeve 70. Thus, no portion of the one or more magnets 80 can contact the sensor rod 35 as the sensor rod 35 moves along the longitudinal axis during operation of the fluid cylinder 10. Optionally, the one or more magnets 80 can be provided in a cutout (or cutouts) 77 of the sleeve 70, such as shown in FIG. 2.

[0023] At least a portion of the outer wall 75 of the sleeve 70 can be fixed to the inner wall 64 of the body 60. According to embodiments of the disclosed subject matter, the outer wall 75 of the sleeve 70 can be fixed to the inner wall 64 via friction fit, snap fit, or threading. The sleeve 70 in FIG. 2, for instance, can be inserted in the bore 61 such that the outer wall 75 frictionally engages with the inner wall 64 of the body 60.

[0024] Each of the one or more magnets 80 is fixedly disposed between the sleeve 70 and the body 60. For instance, at the very least the sleeve 70 retained in the bore 61 can retain the one or more magnets 80 in position. Hence, according to one or more embodiments, the sleeve 70 is also referred to as a magnet ring. The one or more magnets 80 are also molded between the body 60 and the sleeve 70. According to embodiments of the disclosed subject matter, the one or more magnets 80 can be so-called in-molded to the inner wall 64 of the body 60 or can be so-called out-molded to the outer wall 75 of the sleeve 70. Such molding can occur prior to inserting the sleeve 70 into the bore 61 to fixedly attach the sleeve 70 to the body 60.

[0025] FIG. 3 is a sectional view of a fluid cylinder 10 according to one or more embodiments of the disclosed subject matter. Fluid cylinder 10 is similar to the fluid cylinder 10 discussed above for FIG. 1, but notably implements another retainer assembly 150 according to embodiments of the disclosed subject matter. FIG. 4 shows an enlarged portion of FIG. 3, and FIG. 4 shows a sectional view of the retainer assembly 150.

[0026] The retainer assembly 150 is comprised of a body 160, a sleeve 170, and one or more magnets 180. According to one or more embodiments, the body 160, the sleeve 170, and the one or more magnets 180 may be the only components of the retainer assembly 150. Thus, the retainer assembly 150 consists of the body 160, the sleeve 170, and the one or more magnets 180.

[0027] The body 160 can be annular and defines a bore 161 that extends from a first end 162 of the body 160 to a second end 163 of the body 160. The bore 161 is defined by an inner wall 164 of the body 160 opposite an outer wall 165 of the body 160. The bore 161 is adapted to receive the sensor rod 35, such as shown in FIG. 3 and FIG. 4, whereby the sensor rod 35 extends from the first end 162 and the second end 163 of the body 160. According to one or more embodiments, the body 160 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 160, unless the one or more magnets 180 are prevented from direct contact with the body 160.

[0028] The body 160 can be considered to have a first body portion 168 and a second body portion 169. The first body portion 168 and the second body portion 169 can be associated with (and indeed include) the first end 162 and the second end 163 of the body 160, respectively.

[0029] As shown in FIG. 5, the bore 161 can have a greater cross-sectional area or diameter, as defined by the inner wall 164, at the first end 162 as compared to the second end 163. According to one or more embodiments, the inner wall 164 at the first end 162 of the body 160 can be in the form of a hexagon (or some other polygon) when viewed from the first end 162 of the body 160. The shape of the inner wall 164 at the first end 162 can match a torque tool (e.g., a hex key) to assemble the body 160 to the corresponding piston and rod assembly 18, 19.

[0030] Additionally or alternatively, an outer diameter of the body 160, as defined by the outer wall 165, can be greater at a first end portion of the body 160 associated with the first end 162 of the body 160 as compared to an outer diameter of the body 160, as defined by the outer wall 165, at a second end portion of the body 160 associated with the second end 163 of the body 160. According to one or more embodiments, the outer diameter of the outer wall 165 for the first body portion 168 can be constant and the outer diameter of the outer wall 165 for the second body portion 169 can vary, such as according to the plateau and valleys shown in FIG. 5. The relief features of the outer wall 165 at the second body portion 169 can be to reliably and effectively interface with the piston and rod assembly 18. Depending upon whether the first body portion 168 is exposed (as in FIG. 3 and FIG. 4) or unexposed (e.g., inside the counterbore 22 at the end of the rod 21 as in FIG. 7), some or all of the outer wall 165 can be threaded to interface with the corresponding piston and rod assembly 18, 19. For instance, when the first body portion 168 is exposed the outer wall 165 at the first body portion 168 may not have threads and some or all of the outer wall 165 at the second body portion 169 may be threaded. On the other hand, when the first body portion 168 is not exposed, threads may be provided in the outer wall 165 at the first body portion 168 and / or at the second body portion 169.

[0031] The sleeve 170 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 170 can be made of nylon (polyamide) filled with an additive, such as glass. Alternatively, the sleeve 170 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 170. The sleeve 170 is disposed in the bore 161 of the body 160 at a portion of the inner wall 164 such as shown in FIG. 5. Thus, the sleeve 170 is radially outward of the sensor rod 35, such as shown in FIG. 3 and FIG. 4. More specifically, the inner wall 174 of the sleeve 170 can contact the sensor rod 35. In this regard, the sleeve 170 can protect the sensor rod 35 as the sensor rod 35 travels along the longitudinal axis 16 during operation of the fluid cylinder 10.

[0032] The length of the sleeve 170 can be less than the length of the body 160. According to one or more embodiments, no portion of the sleeve 170 may extend from either the first end 162 or the second end 163 of the body 160. Note, however, that in this example, the length of the sleeve 170 can be longer than that of the sleeve 70 for FIG. 2. For instance, the sleeve 170 can extend from the second end 163 of the body 160 into the first body portion 168 of the body 160.

[0033] Such extending may also mean that an inner-most diameter of the sleeve 170, as defined by the inner wall 174 of the sleeve 170, is less than an inner-most diameter of the inner wall 164 of the body 160. In this example, the inner wall 174 of the sleeve 170 can have an internal diameter less than any internal diameter defined by the inner wall 164 of the body 160.

[0034] According to one or more embodiments, the inner wall 174 of the sleeve 170 can have a substantially constant diameter, at least from the second end 163 of the body 160. However, in this example, an end of the sleeve 170 opposite the second end 163 of the body 160 can be tapered at an angle θ relative to the longitudinal axis 16 (e.g., at or about sixty degrees combined for opposite sides of the inner wall 174). Such tapering can facilitate passage of the sensor rod 35 through the retainer assembly 150.

[0035] Each of the one or more magnets 180 can be an angular magnet and is disposed radially outward of at least a portion of an outer wall 175 of the sleeve 170. Thus, each of the one or more magnets 180 is disposed between the sleeve 170 and the body 160, at least in a radial direction of the body 160. In this regard, the one or more magnets 180 are provided also radially outward of the sensor rod 35. However, as shown in FIG. 5, no portion of the one or more magnets 180 can be exposed from the body 160 or the sleeve 170. Thus, no portion of the one or more magnets 180 can contact the sensor rod 35. Optionally, the one or more magnets 180 can be provided in a cutout (or cutouts) 177 of the sleeve 170, such as shown in FIG. 5.

[0036] At least a portion of the outer wall 175 of the sleeve 170 can be fixed to the inner wall 164 of the body 160. According to embodiments of the disclosed subject matter, the outer wall 175 of the sleeve 170 can be fixed to the inner wall 164 via friction fit, snap fit, or threading. The sleeve 170 in FIG. 5, for instance, can be inserted in the bore 161 such that elevations (e.g., ridges or projections) in the outer wall 175 snap fit with corresponding recesses in the inner wall 164 of the body 160.

[0037] Each of the one or more magnets 180 are fixedly disposed between the sleeve 170 and the body 160. For instance, at the very least the sleeve 170 retained in the bore 161 can retain the one or more magnets 180 in position. The one or more magnets 180 are also molded between the body 160 and the sleeve 170. According to embodiments of the disclosed subject matter, the one or more magnets 180 can be so-called in-molded to the inner wall 164 of the body 160 or can be so-called out-molded to the outer wall 175 of the sleeve 170. Such molding can occur prior to inserting the sleeve 170 into the bore 161 to fixedly attach the sleeve 170 to the body 160.

[0038] FIG. 6 shows a sectional view of another retainer assembly 250. The retainer assembly 250 is comprised of a body 260, a sleeve 270, and one or more magnets 280. According to one or more embodiments, the body 260, the sleeve 270, and the one or more magnets 280 may be the only components of the retainer assembly 250. Thus, the retainer assembly 250 consists of the body 260, the sleeve 270, and the one or more magnets 280.

[0039] The body 260 can be annular and defines a bore 261 that extends from a first end 262 of the body 260 to a second end 263 of the body 260. The bore 261 is defined by an inner wall 264 of the body 260 opposite an outer wall 265 of the body 260. The bore 261 is adapted to receive the sensor rod 35, such as shown above, whereby the sensor rod 35 extends from the first end 262 and the second end 263 of the body 260. According to one or more embodiments, the body 260 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 260, unless the one or more magnets 280 are prevented from direct contact with the body 260.

[0040] The body 260 can be considered to have a first body portion 268 and a second body portion 269. The first body portion 268 and the second body portion 269 can be associated with (and indeed include) the first end 262 and the second end 263 of the body 260, respectively.

[0041] As shown in FIG. 6, the bore 261 can have a greater cross-sectional area or diameter, as defined by the inner wall 264, at the first end 262 as compared to the second end 263. According to one or more embodiments, the inner wall 264 at the first end 262 of the body 260 can be in the form of a hexagon (or some other polygon) when viewed from the first end 262 of the body 260. The shape of the inner wall 264 at the first end 262 can match a torque tool (e.g., a hex key) to assemble the body 260 to the corresponding piston and rod assembly 18, 19.

[0042] Additionally or alternatively, an outer diameter of the body 260, as defined by the outer wall 265, can be greater at a first end portion of the body 260 associated with the first end 262 of the body 260 as compared to an outer diameter of the body 260, as defined by the outer wall 265, at a second end portion of the body 260 associated with the second end 263 of the body 260. According to one or more embodiments, the outer diameter of the outer wall 265 for the first body portion 268 can be constant and the outer diameter of the outer wall 265 for the second body portion 269 can vary, such as according to the plateau and valleys shown in FIG. 6. The relief features of the outer wall 265 at the second body portion 269 can be to reliably and effectively interface with the piston and rod assembly 18. Depending upon whether the first body portion 268 is exposed (e.g., as in FIG. 1 or FIG. 3 and FIG. 3) or unexposed (e.g., inside the counterbore 22 at the end of the rod 21 as in FIG. 7), some or all of the outer wall 265 can be threaded to interface with the corresponding piston and rod assembly 18, 19. For instance, when the first body portion 268 is exposed the outer wall 265 at the first body portion 268 may not have threads and some or all of the outer wall 265 at the second body portion 269 may be threaded. On the other hand, when the first body portion 268 is not exposed, threads may be provided in the outer wall 265 at the first body portion 268 and / or at the second body portion 269.

[0043] The sleeve 270 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 270 can be made of nylon (polyamide) filled with an additive, such as glass. Alternatively, the sleeve 270 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 270. The sleeve 270 is disposed in the bore 261 of the body 260 at a portion of the inner wall 264 such as shown in FIG. 6. Thus, the sleeve 270 is radially outward of the sensor rod 35, such as discussed above. More specifically, the inner wall 274 of the sleeve 270 can contact the sensor rod 35. In this regard, the sleeve 270 can protect the sensor rod 35 as the sensor rod 35 travels along the longitudinal axis 16 during operation of the fluid cylinder 10.

[0044] The length of the sleeve 270 can be less than the length of the body 260. According to one or more embodiments, no portion of the sleeve 270 may extend from either the first end 262 or the second end 263 of the body 260. Note, however, that in this example, the length of the sleeve 270 can be longer than that of the sleeve 70 for FIG. 2. For instance, the sleeve 270 can extend from the second end 263 of the body 260 into the first body portion 268 of the body 260.

[0045] Such extending may also mean that an inner-most diameter of the sleeve 270, as defined by the inner wall 274 of the sleeve 270, is less than an inner-most diameter of the inner wall 264 of the body 260. In this example, the inner wall 274 of the sleeve 270 can have an inner diameter less than any inner diameter defined by the inner wall 264 of the body 260.

[0046] According to one or more embodiments, the inner wall 274 of the sleeve 270 can have a substantially constant diameter, at least from the second end 263 of the body 260. However, in this example, an end of the sleeve 270 opposite the second end 263 of the body 260 can be tapered at an angle θ relative to the longitudinal axis 16 (e.g., at or about sixty degrees combined for opposite sides of the inner wall 274). In this example, the inner wall 264 of the body 260 can also be tapered relative to the longitudinal axis 16. Optionally, the angles of taper for the inner wall 274 of the sleeve 270 and the inner wall 264 of the body 260 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 35 through the retainer assembly 250.

[0047] Each of the one or more magnets 280 can be an angular magnet and is disposed radially outward of at least a portion of an outer wall 275 of the sleeve 270. Thus, each of the one or more magnets 280 is disposed between the sleeve 270 and the body 260, at least in a radial direction of the body 260. In this regard, the one or more magnets 280 are provided also radially outward of the sensor rod 35. However, as shown in FIG. 6, no portion of the one or more magnets 280 can be exposed from the body 260 or the sleeve 270. Thus, no portion of the one or more magnets 280 can contact the sensor rod 35. Optionally, the one or more magnets 280 can be provided in a cutout (or cutouts) 277 of the sleeve 270, such as shown in FIG. 6.

[0048] At least a portion of the outer wall 275 of the sleeve 270 can be fixed to the inner wall 264 of the body 260. According to embodiments of the disclosed subject matter, the outer wall 275 of the sleeve 270 can be fixed to the inner wall 264 via friction fit, snap fit, or threading. As shown in FIG. 6, the inner wall 264 of the body 260 can have a plurality of sets of one or more grooves adapted to interface with corresponding projects on the outer wall 275 of the sleeve 270. 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.

[0049] Each of the one or more magnets 280 is fixedly disposed between the sleeve 270 and the body 260. For instance, at the very least the sleeve 270 retained in the bore 261 can retain the one or more magnets 280 in position. The one or more magnets 280 are also molded between the body 260 and the sleeve 270. According to embodiments of the disclosed subject matter, the one or more magnets 280 can be so-called in-molded to the inner wall 264 of the body 260 or can be so-called out-molded to the outer wall 275 of the sleeve 270. Such molding can occur prior to inserting the sleeve 270 into the bore 261 to fixedly attach the sleeve 270 to the body 260.Industrial Applicability

[0050] 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.

[0051] Retainer assemblies according to embodiments of the disclosed subject matter, such as retainer assemblies 50, 150, 250 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 30 in fluid cylinder 10 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 80, 180, 280 between body 60, 160, 260 and sleeve 70, 170, 270. 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.

[0052] 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.

[0053] Retainer assemblies according to embodiments of the disclosed subject matter can also provide support for the sensor rod and avoid or minimize damage to the sensor and the magnet upon assembly and / or operation of the fluid cylinder. For instance, the sensor rod can be retained at the longitudinal axis of the fluid cylinder using retainer assemblies according to embodiments of the disclosed subject matter.

Claims

1. A hydraulic cylinder (10) comprising: an elongate body (12) defining an internal cavity (14) that extends along a longitudinal axis (16) of the elongate body (12); a pair of end caps (26, 28) at opposite ends of the elongate body (12); a piston and rod assembly (18, 19) at least partially in the internal cavity (14), the piston and rod assembly (18, 19) being movable in a direction of the longitudinal axis (16); a position sensor (32) and a sensor rod (35) in the internal cavity (14), the sensor rod (35) extending along the longitudinal axis (16); and a sensor retainer assembly (50, 150, 250) in the internal cavity (14), the sensor retainer assembly (50, 150, 250) being coaxial with the sensor rod (35) and adapted to retain the sensor rod (35) at the longitudinal axis (16), the sensor retainer assembly (50, 150, 250) including: an annular body (60, 160, 260) defining a bore (61, 161, 261) extending from opposite ends of the annular body (60, 160, 260), the bore (61, 161, 261) being adapted to receive the sensor rod (35) such that the sensor rod (35) extends from the opposite ends of the annular body (60, 160, 260), a magnet ring (70, 170, 270) disposed in the bore (61, 161, 261) at an inner wall (64, 164, 264) of the annular body (60, 160, 260), the magnet ring (70, 170, 270) being radially outward of the sensor rod (35), and one or more magnets (80, 180, 280) fixedly disposed between the annular body (60, 160, 260) and the magnet ring (70, 170, 270) in a radial direction of the annular body (60, 160, 260), the one or more magnets (80, 180, 280) being radially outward of the sensor rod (35), wherein each of the one or more magnets (80, 180, 280) is fixedly molded between the annular body (60, 160, 260) and the magnet ring (70, 170, 270).

2. The hydraulic cylinder according to Claim 1, wherein the magnet ring (70, 170, 270) is made of a non-metallic material.

3. The hydraulic cylinder according to Claim 1, wherein no portion of each of the one or more magnets (80, 180, 280) contacts the sensor rod (35).

4. The hydraulic cylinder according to Claim 1, wherein an inner wall (64, 164, 264) of the magnet ring (70, 170, 270) contacts the sensor rod (35).

5. The hydraulic cylinder according to Claim 1, wherein no portion of the magnet ring (70, 170, 270) extends from the annular body (60, 160, 260).

6. A method regarding a retainer assembly (50, 150, 250) adapted to interface with a sensor rod (35) of an in-cylinder position sensor assembly (30) of a fluid cylinder (10), the method comprising: providing an annular body (60, 160, 260) of the retainer assembly (50, 150, 250), the annular body (60, 160, 260) defining a bore (61, 161, 261) extending from a first end (62, 162, 262) of the annular body (60, 160, 260) to a second end (63, 163, 263) of the annular body (60, 160, 260) opposite the first end (62, 162, 262); providing a sleeve (70, 170, 270) of the retainer assembly (50, 150, 250), the sleeve (70, 170, 270) being disposed in the bore (61, 161, 261) at an inner wall (64, 164, 264) of the annular body (60, 160, 260); and providing one or more magnets (80, 180, 280) of the retainer assembly (50, 150, 250), the one or more magnets (80, 180, 280) being fixedly molded between the annular body (60, 160, 260) and the sleeve (70, 170, 270) in a radial direction of the annular body (60, 160, 260).

7. The method according to Claim 6, further comprising: assembling the retainer assembly (50, 150, 250) to a piston and rod assembly (18, 19) of the fluid cylinder (10); providing the sensor rod (35) through the bore (61, 161, 261) of the annular body (60, 160, 260) of the retainer assembly (50, 150, 250) such that the sensor rod (35) extends from the first end (62, 162, 262) and the second end (63, 163, 263) of the annular body (60, 160, 260) and is radially inward of the piston and rod assembly (18, 19); and inserting the sleeve (70, 170, 270) in the bore (61, 161, 261) from the second end (63, 163, 263) of the annular body (60, 160, 260) such that each of the one or more magnets (80, 180, 280) is between the annular body (60, 160, 260) and the sleeve (70, 170, 270) in the radial direction of the annular body (60, 160, 260).

8. The method according to Claim 6, wherein each of the one or more magnets (80, 180, 280) is in-molded to the inner wall (64, 164, 264) of the annular body (60, 160, 260) or out-molded to an outer wall (75, 175, 275) of the sleeve (70, 170, 270) prior to assembling the sleeve (70, 170, 270) and the annular body (60, 160, 260).

9. The method according to Claim 6, wherein the sleeve (70, 170, 270) is made of a non-metallic material, wherein a length of the sleeve (70, 170, 270) is less than a length of the annular body (60, 160, 260), and wherein an outer wall (75, 175, 275) of the sleeve (70, 170, 270) is fixed to the inner wall (64, 164, 264) of the annular body (60, 160, 260) via friction fit, snap-fit, or threading, and wherein each of the one or more magnets (80, 180, 280) is provided in a cutout (77, 177, 277) of the sleeve (70, 170, 270).