Patent Description:
Electromagnetic solenoids generally include a barrel and a moving armature or piston within the barrel. Since the moving armature or piston contact the inner surface of the barrel during use, friction between the two parts can cause extreme metal fatigue and wear, which can reduce life expectancy of the solenoid. Accordingly, additional components within the solenoid, i.e., liners, which can reduce friction between the moving armature or piston and the inner surface of the barrel during use are desired. Low friction bearing liners are for example known from <CIT>.

The invention is directed in a first aspect to a low friction bearing liner with the features of claim <NUM> and in a second aspect to a low friction bearing liner with the features of claim <NUM>. Features defined in the independent claims, if referred to as optional in the description below by the modal verb "may", are to be considered as non-optional features.

According to yet another aspect, a solenoid may include a barrel, an armature within the barrel, and a low friction bearing liner disposed between an inner surface of the barrel and an outer surface of the armature. The low friction bearing liner for a solenoid may include a core layer, a first outer layer overlying a first surface of the core layer, a second outer layer overlying the first outer layer, a first inner layer overlying a second surface of the core layer that is opposite of the first surface of the core layer, and a second inner layer overlying the first inner layer. The first outer layer may include a fluoropolymer material and may have a melt flow rate of at least about <NUM>/<NUM> at <NUM>. The second outer layer may include a fluoropolymer material distinct from the fluoropolymer material of the first outer layer and may have a surface coefficient of friction of not greater than about <NUM>. The first inner layer may include a fluoropolymer material and may have a melt flow rate of at least about <NUM>/<NUM> at <NUM>. The second inner layer may include a fluoropolymer material distinct from the fluoropolymer material of the first outer layer and may have a surface coefficient of friction of not greater than about <NUM>.

According to yet another aspect, a solenoid may include a barrel, an armature within the barrel, and a low friction bearing liner disposed between an inner surface of the barrel and an outer surface of the armature. The low friction bearing liner for a solenoid may include a core layer, a first outer layer overlying a first surface of the core layer, a second outer layer overlying the first outer layer, a first inner layer overlying a second surface of the core layer that is opposite of the first surface of the core layer, and a second inner layer overlying the first inner layer. The first outer layer may include at least one of a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, a modified PTFE material, or a combination thereof. The second outer layer may include a polytetrafluoroethylene material or a mixture of a polytetrafluoroethylene material and a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, a modified PTFE material. The first inner layer may include a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, a modified PTFE material, or a combination thereof. The second inner layer may include a polytetrafluoroethylene material or a mixture of a polytetrafluoroethylene material and a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, a modified PTFE material.

Embodiments are illustrated by way of example and are not limited to the accompanying figures.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.

The following discussion will focus on specific implementations and embodiments of the teachings. The detailed description is provided to assist in describing certain embodiments and should not be interpreted as a limitation on the scope or applicability of the disclosure or teachings. It will be appreciated that other embodiments can be used based on the disclosure and teachings as provided herein.

Embodiments described herein are generally directed to a low friction bearing liner for a solenoid. According to certain embodiments, the low friction bearing liner may include a five component multilayer structure that includes a core layer, a first outer layer overlying a first surface of the core layer, a second outer layer overlying the first outer layer, a first inner layer overlying a second surface of the core layer that is opposite of the first surface of the core layer, and a second inner layer overlying the first inner layer.

For purposes of illustration, <FIG> includes an illustration of a low friction bearing liner <NUM> according to embodiments described herein. As shown in <FIG>, a low friction bearing liner <NUM> may include a core layer <NUM>, a first outer layer <NUM> overlying a first surface <NUM> of the core layer <NUM>, a second outer layer <NUM> overlying the first outer layer <NUM>, a first inner layer <NUM> overlying a second surface <NUM> of the core layer <NUM> that is opposite of the first surface <NUM> of the core layer <NUM>, and a second inner layer <NUM> overlying the first inner layer <NUM>.

According to a certain embodiments, the core layer <NUM> may include a polyimide material. According to certain embodiments, the core layer <NUM> may include a particular content of polyimide material. For example, the core layer <NUM> may include a content of polyimide material of at least about <NUM> wt. % for a total weight of the core layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the core layer <NUM> may include a content of polyimide material of not greater than about <NUM> wt. % for a total weight of the core layer <NUM>. It will be appreciated that the content of polyimide in the core layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of polyimide in the core layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the core layer <NUM> may consist of a polyimide material.

According to yet other embodiments, the first outer layer <NUM> may include a fluoropolymer material. According to certain embodiments, the first outer layer <NUM> may include a particular content of fluoropolymer material. For example, the first outer layer <NUM> may include a content of fluoropolymer material of at least about <NUM> wt. % for a total weight of the first outer layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the first outer layer <NUM> may include a content of fluoropolymer material not greater than about <NUM> wt. % for a total weight of the first outer layer <NUM>. It will be appreciated that the content of fluoropolymer material in the first outer layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of fluoropolymer material in the first outer layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the first outer layer <NUM> may consist of a fluoropolymer material.

According to still other embodiments, the first outer layer <NUM> may have a particular melt flow rate. It will be appreciated that for purposes of embodiments described herein, the melt flow rate of a particular material or layer may be measured according to ASTM # D-<NUM> at a temperature of <NUM>. According to certain embodiments, the first outer layer <NUM> may have a melt flow rate of at least about <NUM>/<NUM>.

According to yet other embodiments, the first outer layer <NUM> may include at least one of a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, a modified PTFE material, or a combination thereof. According to still other embodiments, the first outer layer <NUM> may consist of at least about of a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, a modified PTFE material, or a combination thereof.

According to yet other embodiments, the first outer layer <NUM> may include a fluorinated ethylene propylene material. According to certain embodiments, the first outer layer <NUM> may include a particular content of fluorinated ethylene propylene material. For example, the first outer layer <NUM> may include a content of fluorinated ethylene propylene material of at least about <NUM> wt. % for a total weight of the first outer layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the first outer layer <NUM> may include a content of fluorinated ethylene propylene material not greater than about <NUM> wt. % for a total weight of the first outer layer <NUM>. It will be appreciated that the content of fluorinated ethylene propylene material in the first outer layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of fluorinated ethylene propylene material in the first outer layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the first outer layer <NUM> may consist of a fluorinated ethylene propylene material.

According to yet other embodiments, the first outer layer <NUM> may include a perfluoroalkoxy alkane material. According to certain embodiments, the first outer layer <NUM> may include a particular content of perfluoroalkoxy alkane material. For example, the first outer layer <NUM> may include a content of perfluoroalkoxy alkane material of at least about <NUM> wt. % for a total weight of the first outer layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the first outer layer <NUM> may include a content of perfluoroalkoxy alkane material not greater than about <NUM> wt. % for a total weight of the first outer layer <NUM>. It will be appreciated that the content of perfluoroalkoxy alkane material in the first outer layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of perfluoroalkoxy alkane material in the first outer layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the first outer layer <NUM> may consist of a perfluoroalkoxy alkane material.

According to yet other embodiments, the first outer layer <NUM> may include a modified PTFE material. According to certain embodiments, the first outer layer <NUM> may include a particular content of modified PTFE material. For example, the first outer layer <NUM> may include a content of modified PTFE material of at least about <NUM> wt. % for a total weight of the first outer layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the first outer layer <NUM> may include a content of modified PTFE material not greater than about <NUM> wt. % for a total weight of the first outer layer <NUM>. It will be appreciated that the content of modified PTFE material in the first outer layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of modified PTFE material in the first outer layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the first outer layer <NUM> may consist of a modified PTFE material.

According to still other embodiments, the first outer layer <NUM> may contact the first surface <NUM> of the core layer <NUM>. According to still other embodiments, the first outer layer <NUM> may be bonded to the first surface <NUM> of the core layer <NUM>. According to yet other embodiments, the first outer layer <NUM> may be laminated to the first surface <NUM> of the core layer <NUM>.

According to other embodiments, the second outer layer <NUM> may include a fluoropolymer material that is distinct from the fluoropolymer material of the first outer layer <NUM>. According to certain embodiments, the second outer layer <NUM> may include a particular content of fluoropolymer material. For example, the second outer layer <NUM> may include a content of fluoropolymer material of at least about <NUM> wt. % for a total weight of the second outer layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the second outer layer <NUM> may include a content of fluoropolymer material not greater than about <NUM> wt. % for a total weight of the second outer layer <NUM>. It will be appreciated that the content of fluoropolymer material in the second outer layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of fluoropolymer material in the second outer layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the second outer layer <NUM> may consist of a fluoropolymer material that is distinct from the fluoropolymer material of the first outer layer <NUM>.

According to yet other embodiments, the second outer layer <NUM> may have a particular surface coefficient of friction. It will be appreciated that for purposes of embodiments described herein, the surface coefficient of friction of a particular layer may be measured under a <NUM> newton normal force at <NUM>/sec in contact with a quarter inch polyimide wear sphere at a temperature of <NUM> and lubricated with <NUM>,<NUM> cs silicone oil. According to certain embodiments, the second outer layer <NUM> may have a surface coefficient of friction of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or even not greater than about <NUM>. According to still other embodiments, the second outer layer <NUM> may have a surface coefficient of friction of at least about <NUM>, such as, at least about <NUM> or even at least about <NUM>. It will be appreciated that the surface coefficient of friction of the second outer layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the surface coefficient of friction of the second outer layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to other embodiments, the second outer layer <NUM> may include at least one of a polytetrafluoroethylene material or a mixture of a polytetrafluoroethylene material and a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, or a modified PTFE material. According to still embodiments, the second outer layer <NUM> may consist of at least one of a polytetrafluoroethylene material or a mixture of a polytetrafluoroethylene material and a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, or a modified PTFE material.

According to yet other embodiments, the second outer layer <NUM> may include a polytetrafluoroethylene material. According to certain embodiments, the second outer layer <NUM> may include a particular content of polytetrafluoroethylene material. For example, the second outer layer <NUM> may include a content of polytetrafluoroethylene material of at least about <NUM> wt. % for a total weight of the second outer layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the second outer layer <NUM> may include a content of not greater than about <NUM> wt. % for a total weight of the second outer layer <NUM>. It will be appreciated that the content of polytetrafluoroethylene material in the second outer layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of polytetrafluoroethylene material in the second outer layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the second outer layer <NUM> may consist of a second outer layer <NUM>.

According to still other embodiments, the second outer layer <NUM> may contact the first outer layer <NUM>. According to still other embodiments, the second outer layer <NUM> may be bonded to the first outer layer <NUM>. According to yet other embodiments, the second outer layer <NUM> may be laminated to the first outer layer <NUM>.

According to yet other embodiments, the first inner layer <NUM> may include a fluoropolymer material. According to certain embodiments, the first inner layer <NUM> may include a particular content of fluoropolymer material. For example, the first inner layer <NUM> may include a content of fluoropolymer material of at least about <NUM> wt. % for a total weight of the first inner layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the first inner layer <NUM> may include a content of fluoropolymer material not greater than about <NUM> wt. % for a total weight of the first inner layer <NUM>. It will be appreciated that the content of fluoropolymer material in the first inner layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of fluoropolymer material in the first inner layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the first inner layer <NUM> may consist of a fluoropolymer material.

According to still other embodiments, the first inner layer <NUM> may have a particular melt flow rate. It will be appreciated that for purposes of embodiments described herein, the melt flow rate of a particular material or layer may be measured according to ASTM # D-<NUM> at a temperature of <NUM>. According to certain embodiments, the first inner layer <NUM> may have a melt flow rate of at least about <NUM>/<NUM>.

According to yet other embodiments, the first inner layer <NUM> may include at least one of a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, a modified PTFE material, or a combination thereof. According to still other embodiments, the first inner layer <NUM> may consist of at least about of a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, a modified PTFE material, or a combination thereof.

According to yet other embodiments, the first inner layer <NUM> may include a fluorinated ethylene propylene material. According to certain embodiments, the first inner layer <NUM> may include a particular content of fluorinated ethylene propylene material. For example, the first inner layer <NUM> may include a content of fluorinated ethylene propylene material of at least about <NUM> wt. % for a total weight of the first inner layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the first inner layer <NUM> may include a content of fluorinated ethylene propylene material not greater than about <NUM> wt. % for a total weight of the first inner layer <NUM>. It will be appreciated that the content of fluorinated ethylene propylene material in the first inner layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of fluorinated ethylene propylene material in the first inner layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the first inner layer <NUM> may consist of a fluorinated ethylene propylene material.

According to yet other embodiments, the first inner layer <NUM> may include a perfluoroalkoxy alkane material. According to certain embodiments, the first inner layer <NUM> may include a particular content of perfluoroalkoxy alkane material. For example, the first inner layer <NUM> may include a content of perfluoroalkoxy alkane material of at least about <NUM> wt. % for a total weight of the first inner layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the first inner layer <NUM> may include a content of perfluoroalkoxy alkane material not greater than about <NUM> wt. % for a total weight of the first inner layer <NUM>. It will be appreciated that the content of perfluoroalkoxy alkane material in the first inner layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of perfluoroalkoxy alkane material in the first inner layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the first inner layer <NUM> may consist of a perfluoroalkoxy alkane material.

According to yet other embodiments, the first inner layer <NUM> may include a modified PTFE material. According to certain embodiments, the first inner layer <NUM> may include a particular content of modified PTFE material. For example, the first inner layer <NUM> may include a content of modified PTFE material of at least about <NUM> wt. % for a total weight of the first inner layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the first inner layer <NUM> may include a content of modified PTFE material not greater than about <NUM> wt. % for a total weight of the first inner layer <NUM>. It will be appreciated that the content of modified PTFE material in the first inner layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of modified PTFE material in the first inner layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the first inner layer <NUM> may consist of a modified PTFE material.

According to still other embodiments, the first inner layer <NUM> may contact the first surface <NUM> of the core layer <NUM>. According to still other embodiments, the first inner layer <NUM> may be bonded to the first surface <NUM> of the core layer <NUM>. According to yet other embodiments, the first inner layer <NUM> may be laminated to the first surface <NUM> of the core layer <NUM>.

According to other embodiments, the second inner layer <NUM> may include a fluoropolymer material that is distinct from the fluoropolymer material of the first inner layer <NUM>. According to certain embodiments, the second inner layer <NUM> may include a particular content of fluoropolymer material. For example, the second inner layer <NUM> may include a content of fluoropolymer material of at least about <NUM> wt. % for a total weight of the second inner layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the second inner layer <NUM> may include a content of fluoropolymer material not greater than about <NUM> wt. % for a total weight of the second inner layer <NUM>. It will be appreciated that the content of fluoropolymer material in the second inner layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of fluoropolymer material in the second inner layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the second inner layer <NUM> may consist of a fluoropolymer material that is distinct from the fluoropolymer material of the first inner layer <NUM>.

According to yet other embodiments, the second inner layer <NUM> may have a particular surface coefficient of friction. It will be appreciated that for purposes of embodiments described herein, the surface coefficient of friction of a particular layer may be measured under a <NUM> newton normal force at <NUM>/sec in contact with a quarter inch polyimide wear sphere at a temperature of <NUM> and lubricated with <NUM>,<NUM> cs silicone oil. According to certain embodiments, the second inner layer <NUM> may have a surface coefficient of friction of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or even not greater than about <NUM>. According to still other embodiments, the second inner layer <NUM> may have a surface coefficient of friction of at least about <NUM>, such as, at least about <NUM> or even at least about <NUM>. It will be appreciated that the surface coefficient of friction of the second inner layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the surface coefficient of friction of the second inner layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to other embodiments, the second inner layer <NUM> may include at least one of a polytetrafluoroethylene material or a mixture of a polytetrafluoroethylene material and a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, or a modified PTFE material. According to still embodiments, the second inner layer <NUM> may consist of at least one of a polytetrafluoroethylene material or a mixture of a polytetrafluoroethylene material and a fluorinated ethylene propylene material, a perfluoroalkoxy alkane material, or a modified PTFE material.

According to yet other embodiments, the second inner layer <NUM> may include a polytetrafluoroethylene material. According to certain embodiments, the second inner layer <NUM> may include a particular content of polytetrafluoroethylene material. For example, the second inner layer <NUM> may include a content of polytetrafluoroethylene material of at least about <NUM> wt. % for a total weight of the second inner layer <NUM>, such as, at least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or at least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. % or a least about <NUM> wt. According to still other embodiments, the second inner layer <NUM> may include a content of not greater than about <NUM> wt. % for a total weight of the second inner layer <NUM>. It will be appreciated that the content of polytetrafluoroethylene material in the second inner layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the content of polytetrafluoroethylene material in the second inner layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the second inner layer <NUM> may consist of a second inner layer <NUM>.

According to still other embodiments, the second inner layer <NUM> may contact the first inner layer <NUM>. According to still other embodiments, the second inner layer <NUM> may be bonded to the first inner layer <NUM>. According to yet other embodiments, the second inner layer <NUM> may be laminated to the first inner layer <NUM>.

According to yet other embodiments, the low friction bearing liner <NUM> may have a particular first outer layer thickness ratio FOLT/CLT, where FOLT is equal to a thickness of the first outer layer <NUM> and CLT is equal to the thickness of the core layer <NUM>. For example, the low friction bearing liner <NUM> may have a first outer layer thickness ratio FOLT/CLT of at least about <NUM>, such as, at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM>. According to still other embodiments, the low friction bearing liner <NUM> may have a first outer layer thickness ratio FOLT/CLT of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM>. It will be appreciated that the first outer layer thickness ratio FOLT/CLT of the low friction bearing liner <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the first outer layer thickness ratio FOLT/CLT of the low friction bearing liner <NUM> may be any value between any of the minimum and maximum values noted above.

According to yet other embodiments, the low friction bearing liner <NUM> may have a particular second outer layer thickness ratio SOCT/CLT, where SOCT is equal to a thickness of the second outer layer <NUM> and CLT is equal to the thickness of the core layer <NUM>. For example, the low friction bearing liner <NUM> may have a second outer layer thickness ratio SOCT/CLT of at least about <NUM>, such as, at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM>. According to still other embodiments, the low friction bearing liner <NUM> may have a second outer layer thickness ratio SOCT/CLT of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM>. It will be appreciated that the second outer layer thickness ratio SOCT/CLT of the low friction bearing liner <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the second outer layer thickness ratio SOCT/CLT of the low friction bearing liner <NUM> may be any value between any of the minimum and maximum values noted above.

According to yet other embodiments, the low friction bearing liner <NUM> may have a particular first inner layer thickness ratio FILT/CLT, where FILT is equal to a thickness of the first inner layer <NUM> and CLT is equal to the thickness of the core layer <NUM>. For example, the low friction bearing liner <NUM> may have a first inner layer thickness ratio FILT/CLT of at least about <NUM>, such as, at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM>. According to still other embodiments, the low friction bearing liner <NUM> may have a first inner layer thickness ratio FILT/CLT of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM>. It will be appreciated that the first inner layer thickness ratio FILT/CLT of the low friction bearing liner <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the first inner layer thickness ratio FILT/CLT of the low friction bearing liner <NUM> may be any value between any of the minimum and maximum values noted above.

According to yet other embodiments, the low friction bearing liner <NUM> may have a particular second inner layer thickness ratio SILT/CLT, where SILT is equal to a thickness of the second inner layer <NUM> and CLT is equal to the thickness of the core layer <NUM>. For example, the low friction bearing liner <NUM> may have a second inner layer thickness ratio SILT/CLT of at least about <NUM>, such as, at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM>. According to still other embodiments, the low friction bearing liner <NUM> may have a second inner layer thickness ratio SILT/CLT of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM>. It will be appreciated that the second inner layer thickness ratio SILT/CLT of the low friction bearing liner <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the second inner layer thickness ratio SILT/CLT of the low friction bearing liner <NUM> may be any value between any of the minimum and maximum values noted above.

According to yet other embodiments, the core layer <NUM> may have a particular thickness. For example, the core layer <NUM> may have a thickness of at least about <NUM>, such as, at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or even at least about <NUM>. According to still other embodiments, the core layer <NUM> may have a thickness of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM>. It will be appreciated that the thickness of the core layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the thickness of the core layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to yet other embodiments, the first outer layer <NUM> may have a particular thickness. For example, the first outer layer <NUM> may have a thickness of at least about at least about <NUM>, such as, at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or even at least about <NUM>. According to still other embodiments, the first outer layer <NUM> may have a thickness of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM>. It will be appreciated that the thickness of the first outer layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the thickness of the first outer layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to yet other embodiments, the second outer layer <NUM> may have a particular thickness. For example, the second outer layer <NUM> may have a thickness of at least about at least about <NUM>, such as, at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or even at least about <NUM>. According to still other embodiments, the second outer layer <NUM> may have a thickness of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM>. It will be appreciated that the thickness of the second outer layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the thickness of the second outer layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to yet other embodiments, the first inner layer <NUM> may have a particular thickness. For example, the first inner layer <NUM> may have a thickness of at least about at least about <NUM>, such as, at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or even at least about <NUM>. According to still other embodiments, the first inner layer <NUM> may have a thickness of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM>. It will be appreciated that the thickness of the first inner layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the thickness of the first inner layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to yet other embodiments, the second inner layer <NUM> may have a particular thickness. For example, the second inner layer <NUM> may have a thickness of at least about at least about <NUM>, such as, at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or even at least about <NUM>. According to still other embodiments, the second inner layer <NUM> may have a thickness of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM>. It will be appreciated that the thickness of the second inner layer <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the thickness of the second inner layer <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the low friction bearing liner <NUM> may have a particular thickness. For examples, the low friction bearing liner <NUM> may a thickness of at least about <NUM>, such as, at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or at least about <NUM> or even at least about <NUM>. According to still other embodiments, the low friction bearing liner <NUM> may have a thickness of not greater than about <NUM>, such as, not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or even not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or not greater than about <NUM> or even not greater than about <NUM>. It will be appreciated that the thickness of the low friction bearing liner <NUM> may be within a range between any of the minimum and maximum values noted above. It will be further appreciated that the thickness of the low friction bearing liner <NUM> may be any value between any of the minimum and maximum values noted above.

According to still other embodiments, the low friction bearing liner <NUM> may have a particular wear rating. It will be appreciated that for purposes of embodiments described herein, the wear rating may be tested using a Tribometer Test measured under a <NUM> newton normal force at <NUM>/sec in contact with a quarter inch polyimide wear sphere at a running temperature of <NUM> and lubricated with <NUM>,<NUM> cs silicone oil. The wear rating is equal to the number of rotations completed before failure in a Tribometer Test and failure is defined as a <NUM>% increase in COF versus steady-state value during the Tribometer test. According to certain embodiments, the low friction bearing liner <NUM> may have a wear rating of at least about <NUM>,<NUM>, such as, at least about <NUM>,<NUM> or at least about <NUM>,<NUM> or at least about <NUM>,<NUM> or at least about <NUM>,<NUM> or at least about <NUM>,<NUM> or at least about <NUM>,<NUM> or at least about <NUM>,<NUM> or at least about <NUM>,<NUM> or at least about <NUM>,<NUM> or at least about <NUM>,<NUM> or even at least about <NUM>,<NUM>.

According to still other embodiments described herein, the low friction bearing liner may be incorporated into a solenoid.

For purposes of illustration, <FIG> includes an illustration of a solenoid <NUM> according to embodiments described herein. As shown in <FIG>, a solenoid <NUM> may include a barrel <NUM>, an armature <NUM> within the barrel <NUM> and a low friction bearing liner <NUM> disposed between barrel <NUM> of the solenoid <NUM> and the armature <NUM> of the solenoid <NUM>.

According to certain embodiments, the barrel <NUM> of the solenoid <NUM> may also be referred to as a poletube. According to certain embodiments, it may be milled out of a single piece or welded out of at least two pieces.

According to still other embodiments, the armature <NUM> of the solenoid <NUM> may also be referred to as a plunger or piston.

According to certain embodiments, the low friction bearing liner <NUM> may be attached to an inner surface of the barrel <NUM> of the solenoid.

According to yet other embodiments, the solenoid <NUM> may be configured such that the armature <NUM> is a moving part that contacts as surface of the low friction bearing liner <NUM> during movement.

According to still other embodiments, it will be appreciated that the low friction bearing liner <NUM> of the solenoid <NUM>, as shown in <FIG>, may include any of the components and may be described as having any of the characteristics described herein with reference to the low friction bearing liner <NUM> as shown in <FIG>. In particular, the low friction bearing liner <NUM> of the solenoid <NUM> as shown in <FIG>, may include, as shown in <FIG>, a core layer <NUM>, a first outer layer <NUM> overlying a first surface <NUM> of the core layer <NUM>, a second outer layer <NUM> overlying the first outer layer <NUM>, a first inner layer <NUM> overlying a second surface <NUM> of the core layer <NUM> that is opposite of the first surface <NUM> of the core layer <NUM>, and a second inner layer <NUM> overlying the first inner layer <NUM>.

The concepts described herein will be further described in the following Examples, which do not limit the scope of the invention described in the claims.

A sample low friction liner S1 was formed according to embodiments described herein. The sample low friction liner had a core layer of polyimide material with a thickness of <NUM>. Both sides of the core layer were coated with layers of FEP material. The layers of FEP material both had a thickness of <NUM>. Both outer sides of the FEP material were then coated with layers of PTFE material. The layers of PTFE material both had a thickness of <NUM>.

Two comparative sample low friction liners CS1 and CS2 were used for performance comparison. Comparative sample CS1 had a fabric core and was coated with a layer of cast PTFE. The total thickness of the comparative sample CS1 was <NUM>. Comparative sample CS2 had a fabric core and was coated with a layer of modified PTFE. The total thickness of the comparative sample CS2 was <NUM>.

Sample S1 and comparative samples CS1 were tested to determine their coefficient of frictions and wear rating using a Tribometer Test measured under a <NUM> newton normal force at <NUM>/sec in contact with a quarter inch polyimide wear sphere at a running temperature of <NUM> and lubricated with <NUM>,<NUM> cs silicone oil.

<FIG> includes a plot of the wear rotations vs. the coefficient of friction for the sample S1 and comparative samples CS1 and CS2. The results of the comparison tests are shown in table <NUM> below.

Claim 1:
A low friction bearing liner (<NUM>, <NUM>) for a solenoid (<NUM>), wherein the low friction bearing liner (<NUM>, <NUM>) comprises:
a core layer (<NUM>) comprising a polyimide material;
a first outer layer (<NUM>) overlying a first surface (<NUM>) of the core layer (<NUM>), wherein the first outer layer (<NUM>) comprises a fluoropolymer material, and wherein the first outer layer (<NUM>) has a melt flow rate of at least about <NUM>/<NUM> at <NUM>;
a second outer layer (<NUM>) overlying the first outer layer (<NUM>), wherein the second outer layer (<NUM>) comprises a fluoropolymer material distinct from the fluoropolymer material of the first outer layer (<NUM>) and wherein the second outer layer (<NUM>) has a surface coefficient of friction of not greater than about <NUM>;
a first inner layer (<NUM>) overlying a second surface (<NUM>) of the core layer (<NUM>), wherein the second surface (<NUM>) is opposite of the first surface (<NUM>), wherein the first inner layer (<NUM>) comprises a fluoropolymer material, and wherein the first inner layer (<NUM>) has a melt flow rate of at least about <NUM>/<NUM> at <NUM>; and
a second inner layer (<NUM>) overlying the first inner layer (<NUM>), wherein the second inner layer (<NUM>) comprises a fluoropolymer material distinct from the fluoropolymer material of the first inner layer (<NUM>) and wherein the second inner layer (<NUM>) has a surface coefficient of friction of not greater than about <NUM>;
wherein the surface coefficient of friction of a particular layer is measured under a <NUM> Newton normal force at <NUM>/s in contact with a <NUM> (<NUM> inch) polyimide wear sphere at a temperature of <NUM> and lubricated with <NUM><NUM>/s (<NUM>,<NUM> cs) silicone oil.