Bistable Hydraulic Solenoid Valve

Abstract

To provide a hydraulic valve comprising a valve body and a bistable valve spool.SOLUTION: A bistable hydraulic solenoid valve (10) has a valve spool (30) that transitions between two positions, the spool (30) remaining in one of the two positions under an attractive magnetic force when solenoids (12, 22) are not energized. The spool (30) has a first permanent magnet (36) attached to one end (32), and a second permanent magnet (46) attached to another end (34), so that the permanent magnet (36) faces the first solenoid (12), and the permanent magnet (46) faces the second solenoid (22). The solenoid (12) is energized to have a first polarity and the solenoid (22) is energized to have an opposite polarity to make it possible to concurrently push and pull the spool (30) within the valve body (56) between a first position and a second position, the first position establishing a first flow path (f1) and the second position establishing a second flow path (f2) through the valve body (56) and spool (30) so as to enable a flow of hydraulic fluid.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present disclosure relates to the field of hydraulic systems, and in particular to valves used in such systems. [Background technology]

[0002] Motor-operated hydraulic valves are utilized for a variety of purposes in machines, including aircraft. Motors within such valves may be actuated to open or close the valve to a desired position or degree, thereby achieving a desired flow path through the valve. While effective for such purposes, these motors may be heavy, bulky, expensive, complex to manufacture, and energy consuming. For such valves installed within aircraft, the size and weight of these motors may adversely affect fuel economy. The cumulative impact of such additional size and weight of motors within such valves across all hydraulic systems on such aircraft may be significant. Summary of the Invention [Means for solving the problem]

[0003] To address the above problems, according to one aspect of the subject disclosure, a hydraulic valve is provided that includes a valve body and a bistable valve spool. The valve spool is disposed within the valve body and includes a first permanent magnet attached to a first spool end of the valve spool and a second permanent magnet attached to a second spool end of the valve spool. The hydraulic valve also includes a first solenoid disposed adjacent to the first spool end and a second solenoid disposed adjacent to the second spool end. In a first mode of operation, the first solenoid is energized with a first polarity that attracts the first permanent magnet and the second solenoid is energized with an opposite polarity that repels the second permanent magnet to enable the first solenoid and the second solenoid to simultaneously push and pull the valve spool between a first position and a second position.

[0004] According to another aspect of the disclosure, a method is provided for operating a valve spool of a hydraulic valve, the valve spool being disposed within a valve body and including a first permanent magnet attached to a first spool end of the valve spool and a second permanent magnet attached to a second spool end of the valve spool. The hydraulic valve also includes a first solenoid disposed adjacent to the first spool end of the valve spool and a second solenoid disposed adjacent to the second spool end of the valve spool. The first solenoid and the second solenoid are cooperatively actuatable to move the valve spool within the valve body to transition between a first position and a second position. When the first solenoid and the second solenoid are de-energized, the first permanent magnet is operable to maintain the valve spool in the second position and the second permanent magnet is operable to maintain the valve spool in the first position. The method includes energizing a first solenoid and a second solenoid to move the valve spool to the first position in response to receiving a first command to move the valve spool from the second position to the first position. The method also includes energizing the first solenoid and the second solenoid to move the valve spool to the second position in response to receiving a second command to move the valve spool from the first position to the second position.

[0005] According to another aspect of the disclosure, an aircraft system includes a pump, a hydraulic fluid reservoir, an actuator for controlling a controlled component, and a hydraulic valve fluidly coupled to the pump and the hydraulic fluid reservoir and operably coupled to the actuator. The hydraulic valve includes a valve body and a bistable valve spool. The valve spool is disposed within the valve body and includes a first permanent magnet attached to a first spool end of the valve spool and a second permanent magnet attached to a second spool end of the valve spool. The hydraulic valve also includes a first solenoid disposed adjacent the first spool end of the valve spool and a second solenoid disposed adjacent the second spool end of the valve spool. The first solenoid and the second solenoid are cooperatively actuatable to move the valve spool within the valve body to transition between a first position and a second position. When the first solenoid and the second solenoid are not energized, the first permanent magnet is operable to maintain the valve spool in the second position and the second permanent magnet is operable to maintain the valve spool in the first position.

[0006] The discussed features, functions, and advantages may be realized independently in various embodiments or may be combined in other embodiments, further details of such features, functions, and advantages may be understood with reference to the following description and drawings. [Brief description of the drawings]

[0007] [Figure 1A] FIG. 2 is a cross-sectional view of a hydraulic valve in a first position according to a first embodiment of the subject disclosure. [Figure 1B] FIG. 1B is a cross-sectional view of the hydraulic valve of FIG. 1A in a second position. [Figure 2A] FIG. 2 is a cross-sectional view of a hydraulic valve in a first position according to a second embodiment of the subject disclosure. [Figure 2B] FIG. 2B is a cross-sectional view of the hydraulic valve of FIG. 2A in a second position. [Diagram 3] FIG. 13 is a cross-sectional view of a hydraulic valve in a second position according to a third embodiment of the subject disclosure. [Figure 4A]3A-3C are exemplary axial views of a solenoid face of a first solenoid and a solenoid face of a second solenoid according to first and second embodiments of the subject disclosure. [Figure 4B] FIG. 13 is an exemplary axial view of a solenoid face of a first solenoid and a solenoid face of a second solenoid according to a third embodiment of the subject disclosure. [Diagram 5] 1 illustrates an example embodiment of the use of a hydraulic valve of the first, second, or third embodiment according to the subject disclosure. [Figure 6] 1 is a schematic diagram of an exemplary aircraft according to a first, second, or third embodiment of the subject disclosure. [Figure 7] 1 is an illustration of method operations performed in accordance with an example embodiment of the subject disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In view of the above considerations and with reference to Figures 1A and 1B, a three-way hydraulic valve 10 is provided according to a first embodiment of the present disclosure, comprising a valve spool 30, a first solenoid 12, a second solenoid 22, and a first valve body 56. The valve spool 30 includes a spool body 31 formed along a longitudinal axis. The valve spool 30 includes a first permanent magnet 36 attached to a first spool end 32 of the spool body 31. The first permanent magnet 36 includes a first magnetic surface 38. The valve spool further includes a second permanent magnet 46 attached to a second spool end 34 of the spool body 31. The second permanent magnet 46 includes a second magnetic surface 48. The first spool end 32 and the second spool end 34 are disposed at opposite ends of the spool body 31. The first solenoid 12 is disposed adjacent a first spool end 32 of the valve spool 30 and the second solenoid 22 is disposed adjacent a second spool end 34 of the valve spool 30 .

[0009] The first solenoid 12 includes a first iron core 14 including a first solenoid surface 16 facing a first magnetic surface 38 of a first permanent magnet 36, and a first coil 18 wound around the first iron core 14 and configured to generate a first magnetic flux when energized. The first iron core 14 includes a non-magnetic portion 14b around the periphery of the first iron core 14. The second solenoid 22 includes a second iron core 24 including a second solenoid surface 26 facing a second magnetic surface 48 of a second permanent magnet 46, and a second coil 28 wound around the second iron core 24 and configured to generate a second magnetic flux when energized. The second iron core 24 includes a non-magnetic portion 24b around the periphery of the second iron core 24. The iron core 14 of the first solenoid 12 and the iron core 24 of the second solenoid 22 may each include steel in at least a portion of the core. The steel may be a low carbon steel with a relatively high manganese content, such as 1018 cold rolled steel. The first coil 18 and the second coil 28 may comprise magnet wire.

[0010] The valve spool 30 is disposed between the first solenoid 12 and the second solenoid 22 within the valve body 56. The valve spool 30 is movable between a first position (shown in FIG. 1A) and a second position (shown in FIG. 1B) along the longitudinal axis A1. In other words, in a first mode of operation, the first solenoid 12 is excited to have a first polarity that attracts the first permanent magnet 36, and the second solenoid 22 is excited to have an opposite polarity that repels the second permanent magnet 46, such that the first solenoid 12 and the second solenoid 22 can simultaneously push and pull the valve spool 30 within the valve body 56 between the first and second positions. Thus, the first solenoid 12 and the second solenoid 22 are cooperatively drivable to move the valve spool 30 to transition between the first and second positions. In a second mode of operation, the second solenoid 22 is energized with a first polarity that attracts the second permanent magnet 46 and the first solenoid 12 is energized with an opposite polarity that repels the first permanent magnet 36, allowing the first solenoid 12 and the second solenoid 22 to simultaneously push and pull the valve spool 30 between the second position and the first position. The first solenoid 12 and the second solenoid 22 are energized such that the first magnetic flux generated by the first solenoid 12 and the second magnetic flux generated by the second solenoid 22 have opposite polarities, thereby attracting one end of the valve spool 30 to one solenoid while simultaneously repelling the other end of the valve spool 30 from the other solenoid. The valve spool 30 is bistable such that it is either maintained in a first position by a first magnetic force generated between the second core 24 and the second permanent magnet 46, or maintained in a second position by a second magnetic force generated between the first core 14 and the first permanent magnet 36. When the first solenoid 12 and the second solenoid 22 are de-energized, the first permanent magnet 36 is operable to maintain the valve spool 30 in the second position and the second permanent magnet 46 is operable to maintain the valve spool 30 in the first position.

[0011] The first permanent magnet 36 and the second permanent magnet 46 each comprise a rare earth magnet, which may include neodymium. The first magnetic surface 38 and the second magnetic surface 48 each may have a diameter of 0.25 to 1 inch. The thickness of the first permanent magnet 36 may be equal to the thickness of the second permanent magnet 46. The diameter of the first permanent magnet 36 may be equal to the diameter of the second permanent magnet 46. The thickness-to-diameter ratio of the first permanent magnet 36 and the second permanent magnet 46 may be 1.5:1 to 3:1, respectively. The valve body 56 comprises steel. The steel may be a hard steel, such as 440C steel.

[0012] The first permanent magnet 36 and the second permanent magnet 46 are secured to the valve spool 30 by a first cylindrical cup 39 and a second cylindrical cup 49, respectively. In particular, the first permanent magnet 36 and the second permanent magnet 46 are secured to the first spool end 32 and the second spool end 34 of the spool body 31, respectively. In the illustrated embodiment, the first cylindrical cup 39 is secured to the valve spool 30 by a first fastener 60 and the second cylindrical cup 49 is secured to the valve spool 30 by a second fastener 62. However, it will be appreciated that in other embodiments, the first cylindrical cup 39 may additionally or alternatively be secured to the valve spool 30 with an adhesive and the second cylindrical cup 49 may additionally or alternatively be secured to the valve spool 30 with an adhesive.

[0013] 1A, in the first position, a first flow path F1 is established through the valve body 56 and the valve spool 30, thereby allowing hydraulic fluid to flow through the first flow path F1. In the first position, the first solenoid surface 16 is spaced from the first magnetic surface 38 to define a fluid gap between the first solenoid surface 16 and the first magnetic surface 38, and the second solenoid surface 26 is in contact with the second magnetic surface 48. The valve body 56 defines a first port R, a second port P, and a third port C for hydraulic fluid. In the first position, an inner surface of the valve spool 30 abuts the valve body 56 such that the flow of hydraulic fluid through the first port R is stopped, and the valve spool 30 provides the first flow path F1 between the second port P and the third port C when the valve spool 30 is in the first position.

[0014] 1B, in the second position, a second flow path F2 is established through the valve body 56 and the valve spool 30, thereby allowing hydraulic fluid to flow through the second flow path F2. In the second position, the second solenoid face 26 is spaced from the second magnetic surface 48 to define a fluid gap between the second solenoid face 26 and the second magnetic surface 48, and the first solenoid face 16 is in contact with the first magnetic surface 38. In the second position, the inner surface of the valve spool 30 abuts the valve body 56 such that the flow of hydraulic fluid through the second port is stopped, and the valve spool 30 provides the second flow path F2 between the first port R and the third port C when the valve spool 30 is in the second position.

[0015] The hydraulic valve 10 is controlled by a controller and / or processor 40 operatively coupled to the first coil 18 and the second coil 28 to control operation of both the first solenoid 12 and the second solenoid 22 to move the valve spool 30 between a first position and a second position. To place the valve spool 30 in the first position, the processor 40 energizes the second coil 28 to generate a second magnetic flux, thereby attracting the second magnetic surface 48 to the second solenoid face 26, and the processor 40 causes the first coil 18 to generate a first magnetic flux having an opposite polarity to the second magnetic flux, thereby repelling the first magnetic surface 38 from the first solenoid face 16. When the valve spool 30 is placed in the first position, both the first solenoid 12 and the second solenoid 22 are de-energized and the valve spool 30 is maintained in the first position by a first magnetic force generated between the second iron core 24 and the second permanent magnet 46. To place the valve spool 30 in the second position, the processor 40 energizes the second coil 28 to generate a second magnetic flux, thereby repelling the second magnetic surface 48 from the second solenoid face 26, and the processor 40 causes the first coil 18 to generate a first magnetic flux having an opposite polarity to the second magnetic flux, thereby attracting the first magnetic surface 38 to the first solenoid face 16. When the valve spool 30 is placed in the second position, both the first solenoid 12 and the second solenoid 22 are de-energized, and the valve spool 30 is maintained in the second position by the second magnetic force generated between the first iron core 14 and the first permanent magnet 36. Thus, the valve spool 30 is pushed and pulled back and forth between the first position and the second position.

[0016] The processor 40 provides power to the first coil 18, causing the first coil 18 to generate a first magnetic flux, and the processor 40 also provides power to the second coil 28, causing the second coil 28 to generate a second magnetic flux. This power may be, for example, 28 volts direct current (DC) power. It should be understood that in operation, the polarity of the magnetic flux generated by the first coil 18 is opposite to the polarity of the magnetic flux generated by the second coil 28. It should further be understood that the polarities of the first coil 18 and the second coil 28 may be reversed to allow the valve spool 30 to transition between a first position and a second position. As an example, in a first mode of operation, the first coil 18 may be operated to pull the valve spool 30, and the second coil 28 is simultaneously operated in reverse polarity to push the valve spool 30. In a second mode of operation, the first coil 18 may be operated to push the valve spool 30, and the second coil 28 is simultaneously operated in reverse polarity to pull the valve spool 30. As used herein, the term "reverse polarity" means that current is flowing in a first direction through the first coil 18 and current is flowing in a second, opposite direction through the second coil 28. Thus, the direction of current through each of the first coil 18 and second coil 28 may be reversed based on the desired position of the valve spool 30.

[0017] 2A and 2B, a four-way hydraulic valve 110 is provided according to a second embodiment of the present disclosure, comprising a valve spool 130, a first solenoid 112, a second solenoid 122, and a valve body 156. The valve spool 130 includes a spool body 131 formed along a longitudinal axis A2, a first permanent magnet 136 attached to a first spool end 132 of the spool body 131 and including a first magnetic surface 138, and a second permanent magnet 146 attached to a second spool end 134 of the spool body 131 and including a second magnetic surface 148. The first spool end 132 and the second spool end 134 are disposed at opposite ends of the spool body 131. The first solenoid 112 is disposed adjacent a first spool end 132 of the valve spool 130 , and the second solenoid 122 is disposed adjacent a second spool end 134 of the valve spool 130 .

[0018] The first solenoid 112 includes a first iron core 114 including a first solenoid surface 116 facing a first magnetic surface 138 of a first permanent magnet 136, and a first coil 118 wound around the first iron core 114 and configured to generate a first magnetic flux when energized. The first iron core 114 includes a non-magnetic portion 114b around the periphery of the first iron core 114. The second solenoid 122 includes a second iron core 124 including a second solenoid surface 126 facing a second magnetic surface 148 of a second permanent magnet 146, and a second coil 128 wound around the second iron core 124 and configured to generate a second magnetic flux when energized. The second iron core 124 includes a non-magnetic portion 124b around the periphery of the second iron core 124. The iron core 114 of the first solenoid 112 and the iron core 124 of the second solenoid 122 may each include steel in at least a portion of the core. The steel may be a low carbon steel with a relatively high manganese content, such as 1018 cold rolled steel. The first coil 118 and the second coil 128 may comprise magnet wire.

[0019] The valve spool 130 is disposed between the first solenoid 112 and the second solenoid 122 within the valve body 156. The valve spool 130 is movable between a first position (shown in FIG. 2A ) and a second position (shown in FIG. 2B ) along the longitudinal axis A2. In other words, in a first mode of operation, the first solenoid 112 is excited to have a first polarity that attracts the first permanent magnet 136, and the second solenoid 122 is excited to have an opposite polarity that repels the second permanent magnet 146, such that the first solenoid 112 and the second solenoid 122 can simultaneously push and pull the valve spool 130 within the valve body 156 between the first and second positions. Thus, the first solenoid 112 and the second solenoid 122 are cooperatively drivable to move the valve spool 130 to transition between the first and second positions. In a second mode of operation, the second solenoid 122 is energized with a first polarity that attracts the second permanent magnet 146 and the first solenoid 112 is energized with an opposite polarity that repels the first permanent magnet 136, allowing the first solenoid 112 and the second solenoid 122 to simultaneously push and pull the valve spool 130 between the second position and the first position. The first solenoid 112 and the second solenoid 122 are energized such that the first magnetic flux generated by the first solenoid 112 and the second magnetic flux generated by the second solenoid 122 have opposite polarities, thereby attracting one end of the valve spool 130 to one solenoid while simultaneously repelling the other end of the valve spool 130 from the other solenoid. The valve spool 130 is bistable such that it is either maintained in a first position by a first magnetic force generated between the second iron core 124 and the second permanent magnet 146, or maintained in a second position by a second magnetic force generated between the first iron core 114 and the first permanent magnet 136. When the first solenoid 112 and the second solenoid 122 are de-energized, the first permanent magnet 136 is operable to maintain the valve spool 130 in the second position and the second permanent magnet 146 is operable to maintain the valve spool 130 in the first position.

[0020] The first permanent magnet 136 and the second permanent magnet 146 may each comprise a rare earth magnet, which may include neodymium or other materials. The first magnetic surface 138 and the second magnetic surface 148 may each have a diameter of 0.25 to 1 inch. The thickness of the first permanent magnet 136 may be equal to the thickness of the second permanent magnet 146. The diameter of the first permanent magnet 136 may be equal to the diameter of the second permanent magnet 146. The thickness-to-diameter ratio of the first permanent magnet 136 and the second permanent magnet 146 may be 1.5:1 to 3:1, respectively. The valve body 156 comprises steel. The steel may be a hard steel, such as 440C steel.

[0021] The first permanent magnet 136 and the second permanent magnet 146 are secured to the valve spool 130 by a first cylindrical cup 139 and a second cylindrical cup 149, respectively. In particular, the first permanent magnet 136 and the second permanent magnet 146 are secured to the first spool end 132 and the second spool end 134 of the spool body 131, respectively. In the illustrated embodiment, the first cylindrical cup 139 is secured to the valve spool 130 by a first fastener 160 and the second cylindrical cup 149 is secured to the valve spool 130 by a second fastener 162. However, it will be appreciated that in other embodiments, the first cylindrical cup 139 may additionally or alternatively be secured to the valve spool 130 with an adhesive and the second cylindrical cup 149 may additionally or alternatively be secured to the valve spool 130 with an adhesive.

[0022] The valve body 156 defines a first port R1, a second port P, a third port R2, a fourth port C1, and a fifth port C2 for hydraulic fluid.

[0023] 2A , in the first position, the first solenoid surface 116 is spaced from the first magnetic surface 138 to define a fluid gap between the first solenoid surface 116 and the first magnetic surface 138, and the second solenoid surface 126 is in contact with the second magnetic surface 148. The inner surface of the valve spool 130 abuts the valve body 156 such that the flow of hydraulic fluid through the first port R1 is stopped, and the valve spool 130 provides a first fluid flow path G1 between the second port P and the fourth port C1, and a third fluid flow path G3 between the third port R2 and the fifth port C2 when the valve spool 130 is in the first position. Thus, by establishing the first fluid flow path G1 and the third fluid flow path G3 through the valve spool 130 and the valve body 156, hydraulic fluid is permitted to flow through the first fluid flow path G1 and the third fluid flow path G3 in the first position.

[0024] 2B, in the second position, the second solenoid surface 126 is spaced from the second magnetic surface 148 to define a fluid gap between the second solenoid surface 126 and the second magnetic surface 148, and the first solenoid surface 116 is in contact with the first magnetic surface 138. The inner surface of the valve spool 130 abuts the valve body 156 such that the flow of hydraulic fluid through the third port R2 is stopped, and the valve spool 130 provides a second fluid flow path G2 between the first port R1 and the fourth port C1, and a fourth fluid flow path G4 between the second port P and the fifth port C2 when the valve spool 130 is in the second position. Thus, by establishing the second fluid flow path G2 and the fourth fluid flow path G4 through the valve spool 130 and the valve body 156, hydraulic fluid is permitted to flow through the second fluid flow path G2 and the fourth fluid flow path G4 in the second position.

[0025] The hydraulic valve 110 is controlled by a controller and / or processor 140 operatively coupled to the first coil 118 and the second coil 128 to control operation of both the first solenoid 112 and the second solenoid 122 to move the valve spool 130 between a first position and a second position. To place the valve spool 130 in the first position, the processor 140 energizes the second coil 128 to generate a second magnetic flux, thereby attracting the second magnetic surface 148 to the second solenoid face 126, and the processor 140 causes the first coil 118 to generate a first magnetic flux having an opposite polarity to the second magnetic flux, thereby repelling the first magnetic surface 138 from the first solenoid face 116. When the valve spool 130 is placed in the first position, both the first solenoid 112 and the second solenoid 122 are de-energized and the valve spool 130 is maintained in the first position by a first magnetic force generated between the second iron core 124 and the second permanent magnet 146. To place the valve spool 130 in the second position, the processor 140 energizes the second coil 128 to generate a second magnetic flux, thereby repelling the second magnetic surface 148 from the second solenoid surface 126, and the processor 140 causes the first coil 118 to generate a first magnetic flux having an opposite polarity to the second magnetic flux, thereby attracting the first magnetic surface 138 to the first solenoid surface 116. When the valve spool 130 is disposed in the second position, both the first solenoid 112 and the second solenoid 122 are de-energized, and the valve spool 130 is maintained in the second position by a second magnetic force generated between the first iron core 114 and the first permanent magnet 136. Thus, the valve spool 130 is pushed and pulled back and forth between the first position and the second position.

[0026] The processor 140 provides power to the first coil 118, causing the first coil 118 to generate a first magnetic flux, and the processor 140 also provides power to the second coil 128, causing the second coil 128 to generate a second magnetic flux. This power may be, for example, 28 volts direct current (DC) power. As with the first embodiment, it should be understood that in operation, the polarity of the magnetic flux generated by the first coil 118 is opposite to the polarity of the magnetic flux generated by the second coil 128. Additionally, it should be understood that the polarities of the first coil 118 and the second coil 128 may be reversed to allow the valve spool 130 to transition between a first position and a second position.

[0027] 3, a hydraulic valve 210 is provided according to a third embodiment of the present disclosure, comprising a valve spool 230, a first solenoid 212, a second solenoid 222, and a valve body 256. The valve spool 230 includes a spool body 231 formed along a longitudinal axis, a first permanent magnet 236 attached to a first spool end 232 of the spool body 231 and including a first magnetic surface 238, and a second permanent magnet 246 attached to a second spool end 234 of the spool body 231 and including a second magnetic surface 248. The first spool end 232 and the second spool end 234 are disposed at opposite ends of the spool body 231. The first solenoid 212 is positioned adjacent a first spool end 232 of the valve spool 230 , and the second solenoid 222 is positioned adjacent a second spool end 234 of the valve spool 230 .

[0028] The first solenoid 212 includes a first iron core 214 including a first solenoid face 216 facing a first magnetic face 238 of a first permanent magnet 236, and a first coil 218 wound around the first iron core 214 and configured to generate a first magnetic flux when energized. The first coil 218 is covered by a first coil cover 213. The first coil cover 213 may cover the entire cylindrical side of the first coil 218. The end of the first coil 218 is covered by a first coil plate 215. A first non-magnetic support 272 is attached to the valve body 256 and covers the first spool end 232, the first cylindrical cup 239, the first permanent magnet 236, and the first solenoid face 216 of the first solenoid 212.

[0029] The second solenoid 222 includes a second iron core 224 including a second solenoid face 226 facing a second magnetic face 248 of a second permanent magnet 246, and a second coil 228 wound around the second iron core 224 and configured to generate a second magnetic flux when energized. The second coil 228 is covered by a second coil cover 223. The second coil cover 223 can cover the entire cylindrical side of the second coil 228. The end of the second coil 228 is covered by a second coil plate 225. A second non-magnetic support 274 is attached to the valve body 256 and covers the second spool end 234, the second cylindrical cup 249, the second permanent magnet 246, and the second solenoid face 226 of the second solenoid 222.

[0030] The iron core 214 of the first solenoid 212 and the iron core 224 of the second solenoid 222 may each include steel in at least a portion of the core. The steel may be a low carbon steel with a relatively high manganese content, such as 1018 cold rolled steel. The first coil 218 and the second coil 228 may include magnet wire.

[0031] The valve spool 230 is disposed between the first solenoid 212 and the second solenoid 222 within the valve body 256. The valve spool 230 is movable between a first position (not shown) and a second position (shown in FIG. 3) along a longitudinal axis. In other words, in a first mode of operation, the first solenoid 212 is excited to have a first polarity that attracts the first permanent magnet 236, and the second solenoid 222 is excited to have an opposite polarity that repels the second permanent magnet 246, allowing the first solenoid 212 and the second solenoid 222 to simultaneously push and pull the valve spool 230 within the valve body 256 between the first and second positions. Thus, the first solenoid 212 and the second solenoid 222 are cooperatively actuable to move the valve spool 230 to transition between the first and second positions. In a second mode of operation, the second solenoid 222 is energized with a first polarity that attracts the second permanent magnet 246 and the first solenoid 212 is energized with an opposite polarity that repels the first permanent magnet 236, allowing the first solenoid 212 and the second solenoid 222 to simultaneously push and pull the valve spool 230 between the second position and the first position. The first solenoid 212 and the second solenoid 222 are energized such that the first magnetic flux generated by the first solenoid 212 and the second magnetic flux generated by the second solenoid 222 have opposite polarities, thereby attracting one end of the valve spool 230 to one solenoid while simultaneously repelling the other end of the valve spool 230 from the other solenoid. The valve spool 230 is bistable such that it is either maintained in a first position by a first magnetic force generated between the second iron core 224 and the second permanent magnet 246, or maintained in a second position by a second magnetic force generated between the first iron core 214 and the first permanent magnet 236. When the first solenoid 212 and the second solenoid 222 are de-energized, the first permanent magnet 236 is operable to maintain the valve spool 230 in the second position, and the second permanent magnet 246 is operable to maintain the valve spool 230 in the first position.

[0032] The first permanent magnet 236 and the second permanent magnet 246 each comprise a rare earth magnet, which may include neodymium. The first magnetic surface 238 and the second magnetic surface 248 each may have a diameter of 0.25 to 1 inch. The thickness of the first permanent magnet 236 may be equal to the thickness of the second permanent magnet 246. The diameter of the first permanent magnet 236 may be equal to the diameter of the second permanent magnet 246. The thickness-to-diameter ratio of the first permanent magnet 236 and the second permanent magnet 246 may be 1.5:1 to 3:1, respectively. The valve body 256 comprises steel. The steel may be a hard steel, such as 440C steel.

[0033] The first permanent magnet 236 and the second permanent magnet 246 are secured to the valve spool 230 by a first cylindrical cup 239 and a second cylindrical cup 249, respectively. In particular, the first permanent magnet 236 and the second permanent magnet 246 are secured to the first spool end 232 and the second spool end 234 of the spool body 231, respectively. In the illustrated embodiment, the first cylindrical cup 239 is secured to the valve spool 230 by a first fastener 260 and the second cylindrical cup 249 is secured to the valve spool 230 by a second fastener 262. However, it will be appreciated that in other embodiments, the first cylindrical cup 239 may additionally or alternatively be secured to the valve spool 230 with an adhesive and the second cylindrical cup 249 may additionally or alternatively be secured to the valve spool 230 with an adhesive.

[0034] The valve body 256 defines a first port R1, a second port P, a third port R2, a fourth port C1, and a fifth port C2 for hydraulic fluid.

[0035] In the second position (shown in FIG. 3 ), the second solenoid surface 226 is spaced from the second magnetic surface 248 to define a fluid gap between the second solenoid surface 226 and the second magnetic surface 248, and the first solenoid surface 216 is in contact with the first magnetic surface 238. The inner surface of the valve spool 230 abuts the valve body 256 such that the flow of hydraulic fluid through the third port R2 is stopped, and the valve spool 230 provides a first flow path H1 between the fourth port C1 and the first port R1 and a second flow path H2 between the fifth port C2 and the second port P when the valve spool 230 is in the second position. Thus, hydraulic fluid is permitted to flow through the first flow path H1 and the second flow path H2 in the second position by establishing the first flow path H1 and the second flow path H2 through the valve spool 230 and the valve body 256.

[0036] In a first position (not shown), the first solenoid surface 216 is spaced from the first magnetic surface 238 to define a fluid gap between the first solenoid surface 216 and the first magnetic surface 238, and the second solenoid surface 226 is in contact with the second magnetic surface 248. An inner surface of the valve spool 230 abuts the valve body 256 such that the flow of hydraulic fluid through the first port R1 is stopped, and the valve spool 230 provides a third flow path between the fourth port C1 and the second port P, and a fourth flow path between the fifth port C2 and the third port R2 when the valve spool 230 is in the first position. Thus, hydraulic fluid is permitted to flow through the third and fourth flow paths in the first position by establishing the third and fourth flow paths through the valve spool 230 and the valve body 256.

[0037] The hydraulic valve 210 further includes a first plunger 242 and a first sensor 244 provided adjacent to the first solenoid 212, and a second plunger 252 and a second sensor 254 provided adjacent to the second solenoid 222. The first sensor 244 includes a first sensor plate 244a and a first limit switch 244b, and the second sensor 254 includes a second sensor plate 254a and a second limit switch 254b.

[0038] In a first position (not shown), the second magnetic surface 248 pushes the second plunger 252 with the second solenoid surface 226 causing the second sensor 254 to detect the first position of the valve spool 230. The second sensor 254 detects the first position by causing the second plunger 252 to push down on the second sensor plate 254a causing the second limit switch 254b to be pushed into the body of the second sensor 254.

[0039] In the second position (shown in FIG. 3), the first magnetic surface 238 pushes the first plunger 242 with the first solenoid surface 216 causing the first sensor 244 to detect the second position of the valve spool 230. The first sensor 244 detects the second position by causing the first plunger 242 to push down on the first sensor plate 244a causing the first limit switch 244b to be pushed into the body of the first sensor 244.

[0040] The first limit switch 244b may be resiliently biased to urge the first plunger 242 inward toward the center of the valve spool 230, and the second limit switch 254b may be similarly resiliently biased to urge the second plunger 252 inward toward the center of the valve spool 230. The first plunger 242 and the second plunger 252 may be non-magnetic.

[0041] The hydraulic valve 210 is controlled by a controller and / or processor 240 operatively coupled to the first coil 218 and the second coil 228 to control operation of both the first solenoid 212 and the second solenoid 222 to move the valve spool 230 between a first position and a second position. To place the valve spool 230 in the first position, the processor 240 energizes the second coil 228 to generate a second magnetic flux, thereby attracting the second magnetic surface 248 to the second solenoid face 226, and the processor 240 causes the first coil 218 to generate a first magnetic flux having an opposite polarity to the second magnetic flux, thereby repelling the first magnetic surface 238 from the first solenoid face 216. When the valve spool 230 is placed in the first position, both the first solenoid 212 and the second solenoid 222 are de-energized and the valve spool 230 is maintained in the first position by a first magnetic force generated between the second iron core 224 and the second permanent magnet 246. To place the valve spool 230 in the second position, the processor 240 energizes the second coil 228 to generate a second magnetic flux, thereby repelling the second magnetic surface 248 from the second solenoid surface 226, and the processor 240 causes the first coil 218 to generate a first magnetic flux having an opposite polarity to the second magnetic flux, thereby attracting the first magnetic surface 238 to the first solenoid surface 216. When the valve spool 230 is disposed in the second position, both the first solenoid 212 and the second solenoid 222 are de-energized and the valve spool 230 is maintained in the second position by a second magnetic force generated between the first iron core 214 and the first permanent magnet 236. Thus, the valve spool 230 is pushed back and forth between the first and second positions.

[0042] The processor 240 is operatively coupled to the first sensor 244 to receive a detection signal from the first sensor 244 when the first sensor 244 detects the second position by the first plunger 242 depressing the first sensor plate 244a causing the first limit switch 244b to be pushed into the body of the first sensor 244. The processor 240 is also operatively coupled to the second sensor 254 to receive a detection signal from the second sensor 254 when the second sensor 254 detects the first position by the second plunger 252 depressing the second sensor plate 254a causing the second limit switch 254b to be pushed into the body of the second sensor 254. Thus, the processor 240 identifies when the hydraulic valve 210 is in the first position or the second position.

[0043] The processor 240 provides power to the first coil 218, causing the first coil 218 to generate a first magnetic flux, and the processor 240 provides power to the second coil 228, causing the second coil 228 to generate a second magnetic flux. This power may be, for example, 28 volts direct current (DC) power. As with the first and second embodiments, it should be understood that in operation, the polarity of the magnetic flux generated by the first coil 218 is opposite the polarity of the magnetic flux generated by the second coil 228. Additionally, it should be understood that the polarities of the first coil 218 and the second coil 228 may be reversed to allow the valve spool 230 to transition between a first position and a second position.

[0044] Other magnets may be provided along the flow paths in the valve body 256 to capture iron contamination in the fluid flowing through the flow paths. For example, a third magnet 264 may be provided adjacent to the flow path connecting to the second port P, a fourth magnet 266 may be provided adjacent to the flow path connecting to the fifth port C2, and a fifth magnet 268 may be provided adjacent to the flow path connecting to the fourth port C1. The third magnet 264, the fourth magnet 266, and the fifth magnet 268 are configured to magnetically attract iron particles in the hydraulic fluid. Thus, iron contamination may be prevented from clogging each port of the valve spool 230.

[0045] In this embodiment, hydraulic fluid flows freely between the first hydraulic chamber 276 and the second hydraulic chamber 278. The first hydraulic chamber 276 is formed by the first non-magnetic support 272 covering the valve body 256 to create a sealed space for hydraulic fluid. The first non-magnetic support 272 has a hole in which the first iron core 214 is accommodated. The first seal 270a and the second seal 270b provided on the first non-magnetic support 272 prevent hydraulic fluid from leaking out of the first hydraulic chamber 276 and contaminating the first coil 218. The third seal 270c provided between the first non-magnetic support 272 and the valve body 256 prevents hydraulic fluid from leaking out of the first hydraulic chamber 276 into the space between the first non-magnetic support 272 and the valve body 256. The first seal 270a, the second seal 270b, and the third seal 270c are configured to prevent hydraulic fluid from leaking at high return pressures, which can be up to 600 psi.

[0046] Similarly, the second hydraulic chamber 278 is formed by the second non-magnetic support 274 covering the valve body 256 to create a sealed space for hydraulic fluid. The second non-magnetic support 274 has a hole in which the second iron core 224 is received. The fifth seal 270e and the sixth seal 270f on the second non-magnetic support 274 prevent hydraulic fluid from leaking from the second hydraulic chamber 278 and contaminating the second coil 228. The fourth seal 270d between the second non-magnetic support 274 and the valve body 256 prevents hydraulic fluid from leaking from the second hydraulic chamber 278 into the space between the second non-magnetic support 274 and the valve body 256. The fourth seal 270d, the fifth seal 270e, and the sixth seal 270f are configured to prevent hydraulic fluid from leaking at high return pressures, which may be up to 600 psi.

[0047] Thus, when the hydraulic valve 210 transitions from the first position to the second position and the second solenoid surface 226 is moved away from the second magnetic surface 248 to define a fluid gap between the second solenoid surface 226 and the second magnetic surface 248, hydraulic fluid flows from the first hydraulic chamber 276 through the first return flow path 280 and the second return flow path 282 to the second hydraulic chamber 278, such that the volume of fluid in the second hydraulic chamber 278 is expanded to accommodate the fluid gap. Similarly, when the hydraulic valve 210 transitions from the second position to the first position and the first solenoid face 216 is moved away from the first magnetic surface 238 to define a fluid gap between the first solenoid face 216 and the first magnetic surface 238, hydraulic fluid flows from the second hydraulic chamber 278 through the second return flow path 282 and the first return flow path 280 to the first hydraulic chamber 276, causing the volume of fluid in the first hydraulic chamber 276 to expand to accommodate the fluid gap. Thus, the first return flow path 280 and the second return flow path 282 prevent a sudden increase in fluid pressure in the first hydraulic chamber 276 and the second hydraulic chamber 278, thereby keeping both ends of the valve spool 230 wet and the return pressure relatively low.

[0048] Referring to FIG. 4A, an exemplary axial view of the first solenoid surface 16 and the second solenoid surface 26 of the first embodiment of the present disclosure is shown. Although not shown, it will be understood that an exemplary axial view of the first solenoid surface 116 and the second solenoid surface 126 of the second embodiment would be drawn similarly to FIG. 4A. The first solenoid surface 16 comprises a non-magnetic material along the perimeter 16a of the first solenoid surface 16 and steel at a central portion 16b of the first solenoid surface 16. The area of ​​the central portion 16b may be equal to or less than the area of ​​the first magnetic surface 38. Similarly, the second solenoid surface 26 comprises a non-magnetic material along the perimeter 26a of the second solenoid surface 26 and steel at a central portion 26b of the second solenoid surface 26. The area of ​​the central portion 26b may be equal to or less than the area of ​​the second magnetic surface 48.

[0049] 4B, an exemplary axial view of the first solenoid surface 216 and the second solenoid surface 226 of the third embodiment of the present disclosure is shown. Similar to the first and second embodiments, the first solenoid surface 216 comprises a non-magnetic material along the perimeter 216a of the first solenoid surface 216 and steel at a central portion 216b of the first solenoid surface 216. The area of ​​the central portion 216b may be equal to or less than the area of ​​the first magnetic surface 238. Similarly, the second solenoid surface 226 comprises a non-magnetic material along the perimeter 226a of the second solenoid surface 226 and steel at a central portion 226b of the second solenoid surface 226. The area of ​​the central portion 226b may be equal to or less than the area of ​​the second magnetic surface 248. A first plunger 242 is provided at the center of the central portion 216b of the first solenoid face 216 such that the first plunger 242 protrudes outwardly from the first solenoid face 216 when not being depressed by the first magnetic surface 238. Similarly, a second plunger 252 is provided at the center of the central portion 226b of the second solenoid face 226 such that the second plunger 252 protrudes outwardly from the second solenoid face 226 when not being depressed by the second magnetic surface 248.

[0050] FIG. 5 illustrates an exemplary system 300 incorporating a hydraulic valve according to the first, second, or third embodiment of the subject disclosure. The system 300 includes a pump 320, a hydraulic fluid reservoir 330 containing hydraulic fluid, an actuator 350 controlling a controlled component 360, and a hydraulic valve 310 fluidly coupled to the pump 320, the hydraulic fluid reservoir 330, and the actuator 350. The hydraulic valve 310 may be selected from the group consisting of a pilot valve, a shutoff valve, a cut-off valve, and a control valve. It will be understood that these valve types refer to the usage scenario of the valve, not the structure of the valve itself. The controlled component 360 is mechanically coupled to the hydraulic actuator 350 and may be selected from the group consisting of an air brake, a landing gear, a flap, and an aileron. A controller 340 including a processor 342, a non-volatile memory 344, and a volatile memory 346 is operably coupled to the hydraulic valve 310 and configured to control the hydraulic valve 310 to transition between the first position and the second position. The processor 342 executes instructions stored in the non-volatile memory 344 to control the hydraulic valve 310 to transition between a first position and a second position, for example, according to the method described in FIG. 7. For example, when the hydraulic valve 310 is in the first position, a first hydraulic fluid path is established to cause the hydraulic actuator 350 to operate the controlled component 360 to transition to a first state, and when the hydraulic valve 310 is in the second position, a second hydraulic fluid path is established to cause the hydraulic actuator 350 to operate the controlled component 360 to transition to a second state. Although the hydraulic valve 310 of the system 300 is shown as a four-way hydraulic valve having five ports and four possible fluid flow paths, it will be understood that the system 300 is not particularly limited to this port and fluid path configuration, and instead, the system 300 may include a hydraulic valve having three ports and two possible fluid flow paths, for example, as described in the first embodiment.

[0051] Processor 342 includes one or more physical devices that execute instructions. For example, processor 342 may be configured to execute instructions that are part of one or more applications, programs, routines, libraries, objects, components, data structures, or other logical structures. Such instructions may be implemented to perform a task, implement a data type, transform the state of one or more components, achieve a technical effect, or otherwise arrive at a desired result.

[0052] The processor 342 may include one or more physical processors (hardware) that execute software instructions. Additionally or alternatively, the processor 342 may include one or more hardware logic circuits or firmware devices that execute hardware-implemented logic or firmware instructions. The processor 342 may include multiple processors, which may be single-core or multi-core, and the instructions executed on the processor may be configured for sequential, parallel, and / or distributed processing. Individual components of the processor may optionally be distributed across two or more separate devices, which may be remotely located and / or configured for cooperative processing. Aspects of the processor may be virtualized and executed by remotely accessible networked computing devices configured in a cloud computing configuration. In such cases, it will be understood that these virtualized aspects execute on different physical logic processors of various different machines.

[0053] The non-volatile memory 344 includes one or more physical devices that hold instructions executable by the logical processor to implement the methods and processes described herein. When such methods and processes are implemented, the state of the non-volatile memory 344 may be transformed, for example to hold different data.

[0054] The non-volatile memory 344 may include removable and / or built-in physical devices. The non-volatile memory 344 may include optical memory (e.g., CD, DVD, HD-DVD, Blu-Ray disk, etc.), semiconductor memory (e.g., ROM, EPROM, EEPROM, FLASH memory, etc.), and / or magnetic memory (e.g., hard disk drive, floppy disk drive, tape drive, MRAM, etc.), or other mass storage technology. The non-volatile memory 344 may include non-volatile, dynamic, static, read / write, read-only, sequential access, position addressable, file addressable, and / or content addressable devices. It will be appreciated that the non-volatile memory 344 is configured to retain instructions even when power to the non-volatile memory 344 is interrupted.

[0055] Aspects of the processor 342, non-volatile memory 344, and volatile memory 346 may be integrated together in one or more hardware logic components, which may include, for example, field programmable gate arrays (FPGAs), program specific and application specific integrated circuits (PASICs / ASICs), program specific and application specific standard products (PSSPs / ASSPs), systems on a chip (SOCs), and complex programmable logic devices (CPLDs).

[0056] 6 is a schematic diagram of an exemplary aircraft 400 according to the first, second, or third embodiment of the subject disclosure. It will be appreciated that the hydraulic valves of the first, second, or third embodiment may be incorporated into the exemplary system 300 of the exemplary aircraft 400 as described with reference to FIG.

[0057] FIG. 7 illustrates a flow diagram of one exemplary configuration of a method 500 according to one aspect of the subject disclosure. The following description of the method 500 is provided with reference to the software and hardware components illustrated in FIGS. 1A, 1B, 2A, 2B, 3, 4A, 4B, and 5 described above. It will be understood that the method 500 may also be performed using other suitable hardware and software components in other contexts. The method 500 is for operating a valve spool of a hydraulic valve, the valve spool being disposed within a valve body and including a first permanent magnet attached to a first spool end of the valve spool and a second permanent magnet attached to a second spool end of the valve spool. A first solenoid is disposed adjacent to the first spool end of the valve spool and a second solenoid is disposed adjacent to the second spool end of the valve spool. The first solenoid and the second solenoid are cooperatively drivable to move the valve spool within the valve body to transition between a first position and a second position. According to the subject disclosure, when the first solenoid and the second solenoid are de-energized, the first permanent magnet is operable to maintain the valve spool in the second position and the second permanent magnet is operable to maintain the valve spool in the first position.

[0058] At step 502, the method 500 begins. At step 504, the controller receives a first command. At step 508, in response to receiving the first command to move the valve spool from the second position to the first position, the controller may determine whether the valve spool is in the first position. This determination may be performed by the controller by receiving a detection signal from a first sensor that detects contact between the first solenoid surface and the first magnetic surface and / or by receiving a detection signal from a second sensor that detects contact between the second solenoid surface and the second magnetic surface. However, it will be understood that this determination step 508 may be omitted in alternative embodiments. If it is determined that the valve spool is not in the first position, at step 512, the controller energizes the first solenoid and the second solenoid to move the valve spool to the first position, thereby establishing a first flow path in the valve body and the valve spool to allow hydraulic fluid to flow through the first flow path. The first flow path may be established by energizing a second coil to generate a second magnetic flux, thereby attracting the second magnetic surface to the second solenoid surface, and energizing a first coil to generate a first magnetic flux, thereby repelling the first magnetic surface from the first magnetic surface. Once it is determined that the valve spool is in the first position, in step 514, the controller maintains the valve spool in the first position with a first magnetic force.

[0059] At step 506, the controller receives a second command. At step 510, in response to receiving the second command to move the valve spool from the first position to the second position, the controller may determine whether the valve spool is in the second position. This determination may be performed by the controller by receiving a detection signal from a first sensor that detects contact between the first solenoid surface and the first magnetic surface and / or by receiving a detection signal from a second sensor that detects contact between the second solenoid surface and the second magnetic surface. However, it will be understood that this determination step 510 may be omitted in alternative embodiments. If it is determined that the valve spool is not in the second position, at step 518, the controller energizes the first solenoid and the second solenoid to move the valve spool to the second position, thereby establishing a second flow path through the valve body and the valve spool to allow hydraulic fluid to flow through the second flow path. The second flow path may be established by powering the second coil to generate a second magnetic flux, thereby repelling the second magnetic surface from the second solenoid surface, and powering the first coil to generate a first magnetic flux, thereby attracting the first magnetic surface to the first solenoid surface. If it is determined that the valve spool is already in the second position, then in step 516 the controller maintains the valve spool in the second position with the second magnetic force. In step 520, the method 500 returns to the first step 502.

[0060] The systems and processes described herein have the potential advantages of increased reliability, reduced weight, reduced energy consumption, and lower material and manufacturing costs. Intermittent power biases the magnet to a desired magnetic orientation to maintain a desired position of the valve spool. Because the hydraulic solenoid valves of the subject disclosure are bistable, energy consumption is significantly reduced when compared to hydraulic valves that are constantly powered to keep the hydraulic valve in one position. Additionally, the mechanical configuration of the hydraulic valve is simplified when compared to motor-operated hydraulic valves, thereby increasing reliability and reducing weight while saving material and manufacturing costs.

[0061] Further, the present disclosure includes configurations according to the following examples.

[0062] Example 1. A hydraulic valve comprising: a valve body; a bistable valve spool including a first permanent magnet disposed within the valve body and attached to a first spool end of the valve spool and a second permanent magnet disposed to a second spool end of the valve spool; a first solenoid disposed adjacent the first spool end and a second solenoid disposed adjacent the second spool end, wherein in a first mode of operation, the first solenoid is energized to have a first polarity that attracts the first permanent magnet and the second solenoid is energized to have an opposite polarity that repels the second permanent magnet to enable the first solenoid and the second solenoid to simultaneously push and pull the valve spool between a first position and a second position.

[0063] Example 2. The hydraulic valve of Example 1, wherein in a second mode of operation, the second solenoid is energized to have a first polarity that attracts the second permanent magnet and the first solenoid is energized to have an opposite polarity that repels the first permanent magnet to enable the first solenoid and the second solenoid to simultaneously pull the valve spool between the second position and the first position.

[0064] Example 3. The hydraulic valve of Example 1 or 2, wherein when the first solenoid and the second solenoid are de-energized, the first permanent magnet is operable to maintain the valve spool in the second position and the second permanent magnet is operable to maintain the valve spool in the first position.

[0065] Example 4. The hydraulic valve of any one of Examples 1 to 3, wherein the first solenoid includes a first iron core facing the first permanent magnet and the second solenoid includes a second iron core facing the second permanent magnet, and in the first position, the first solenoid is spaced apart from the first permanent magnet and the second solenoid is in contact with the second permanent magnet, and in the second position, the second solenoid is spaced apart from the second permanent magnet and the first solenoid is in contact with the first permanent magnet.

[0066] Example 5. The hydraulic valve of any one of Examples 1 to 4, further comprising a first plunger and a first sensor provided in the first solenoid, and a second plunger and a second sensor provided in the second solenoid, wherein in the first position, a second magnetic surface of the second permanent magnet pushes the second plunger against the second solenoid surface of the second solenoid to cause the second sensor to detect a first position of the valve spool, and in the second position, a first magnetic surface of the first permanent magnet pushes the first plunger against the first solenoid surface of the first solenoid to cause the first sensor to detect a second position of the valve spool.

[0067] Example 6. The hydraulic valve of any one of Examples 1 to 5, wherein the valve body defines a first port, a second port, and a third port, and in a first position, the valve spool provides a first flow path between the second port and the third port, and in a second position, the valve spool provides a second flow path between the first port and the third port.

[0068] Example 7. The hydraulic valve of any one of Examples 1 to 6, wherein a third magnet is provided within the valve body adjacent to at least the flow passage and configured to magnetically attract ferrous particles in the hydraulic fluid within the flow passage.

[0069] Example 8. The hydraulic valve of any one of Examples 1 to 7, wherein the first magnetic surface of the first permanent magnet and the second magnetic surface of the second permanent magnet each have a diameter of 0.25 to 1 inch.

[0070] Example 9. The hydraulic valve of any one of Examples 1 to 8, wherein the thickness-to-diameter ratio of the first permanent magnet and the second permanent magnet is between 1.5:1 and 3:1, respectively.

[0071] Example 10. The hydraulic valve of any one of Examples 1 to 9, wherein the iron core of the first solenoid and the second solenoid each comprises steel in at least a portion of the iron core.

[0072] Example 11. The hydraulic valve of any one of Examples 1 to 10, wherein a first solenoid surface of the first solenoid comprises a non-magnetic material along a perimeter of the first solenoid surface and steel in a central portion of the first solenoid surface, and a second solenoid surface of the second solenoid comprises a non-magnetic material along a perimeter of the second solenoid surface and steel in a central portion of the second solenoid surface.

[0073] Example 12. The hydraulic valve of any one of Examples 1 to 11, wherein the area of ​​the central portion is less than or equal to the area of ​​the first magnetic surface of the first permanent magnet and the area of ​​the second magnetic surface of the second permanent magnet.

[0074] Example 13. The hydraulic valve of any one of examples 1 to 12, wherein the first permanent magnet is securely coupled to the first spool end by a first non-magnetic cup and the second permanent magnet is securely coupled to the second spool end by a second non-magnetic cup.

[0075] Example 14. A method of operating a bistable valve spool of a hydraulic valve, the valve spool including a first permanent magnet disposed within a valve body and attached to a first spool end of the valve spool and a second permanent magnet attached to a second spool end of the valve spool, the hydraulic valve including a first solenoid disposed adjacent the first spool end of the valve spool and a second solenoid disposed adjacent the second spool end of the valve spool, the first solenoid and the second solenoid being cooperatively actuatable to move the valve spool to transition between a first position and a second position, When the solenoid is de-energized, the first permanent magnet is operable to maintain the valve spool in the second position and the second permanent magnet is operable to maintain the valve spool in the first position, the method including, in response to receiving a first command to move the valve spool from the second position to the first position, energizing the first solenoid and the second solenoid to move the valve spool to the first position, and in response to receiving a second command to move the valve spool from the first position to the second position, energizing the first solenoid and the second solenoid to move the valve spool to the second position.

[0076] Example 15. The method of Example 14, wherein to place the valve spool in a first position, the second solenoid is excited to generate a second magnetic flux that attracts the second permanent magnet to the second solenoid, the first solenoid is excited to generate a first magnetic flux that repels the first permanent magnet from the first solenoid, and the valve spool is maintained in the first position by the first magnetic force generated between the second solenoid and the second permanent magnet, and to place the valve spool in a second position, the second solenoid is excited to generate a second magnetic flux that repels the second permanent magnet from the second solenoid, the first solenoid is excited to generate a first magnetic flux that attracts the first permanent magnet to the first solenoid, and the valve spool is maintained in the second position by the second magnetic force generated between the first solenoid and the first permanent magnet.

[0077] Example 16. The method of example 14 or 15, wherein in a first position, flow of hydraulic fluid through a first port of the valve body is stopped by the valve spool and a first flow path between a second port and a third port of the valve body is enabled by the valve spool, and in a second position, flow of hydraulic fluid through the second port of the valve body is stopped by the valve spool and a second flow path between the first port and a third port of the valve body is enabled by the valve spool.

[0078] Example 17. The method of any one of Examples 14 to 16, wherein in a first position, flow of hydraulic fluid through a first port of the valve body is stopped and the valve spool enables a first flow path between a second port and a fourth port of the valve body and a third flow path between a third port and a fifth port of the valve body, and in a second position, flow of hydraulic fluid through the third port is stopped and the valve spool enables a second flow path between the first port and the fourth port and a fourth flow path between the second port and the fifth port.

[0079] Example 18. An aircraft system comprising: a pump; a hydraulic fluid reservoir; an actuator for controlling a controlled component; and a hydraulic valve fluidly coupled to the pump, the hydraulic fluid reservoir, and the actuator, the hydraulic valve comprising: a valve body; a bistable valve spool disposed within the valve body, the bistable valve spool including a first permanent magnet attached to a first spool end of the valve spool and a second permanent magnet attached to a second spool end of the valve spool; a first solenoid disposed adjacent to the first spool end of the valve spool; and a second solenoid disposed adjacent to the second spool end of the valve spool, the first solenoid and the second solenoid being cooperatively actuable to move the valve spool to transition between a first position and a second position, and when the first solenoid and the second solenoid are de-energized, the first permanent magnet is operable to maintain the valve spool in the second position and the second permanent magnet is operable to maintain the valve spool in the first position.

[0080] Example 19. The aircraft system of example 18, wherein the hydraulic valve is selected from the group consisting of a pilot valve, an isolation valve, a cutoff valve, and a control valve.

[0081] Example 20. The aircraft system of example 18 or 19, wherein the controlled components are selected from the group consisting of brakes, landing gear, flaps, and ailerons.

[0082] The subject disclosure includes all novel and non-obvious combinations and subcombinations of the various aspects and techniques disclosed herein. The various aspects and techniques disclosed herein are not necessarily required for every example of the subject disclosure. Moreover, the various aspects and techniques disclosed herein may define patentable subject matter apart from the disclosed examples and may find utility in other implementations not expressly disclosed herein.

[0083] As used herein, "and / or" refers to a logical OR operation, and thus, it will be understood that A and / or B have the following truth table:

[0084] [Table 1]

[0085] To the extent that the terms "include," "including," "having," "including," and variations thereof are used in this specification, such terms are intended to be inclusive in a similar manner to the term "comprising" as an open-ended transition term, without excluding additional or other elements. [Explanation of symbols]

[0086] 10. Three-way hydraulic valve 12 First solenoid 14 First core 14b Non-magnetic part 16 First solenoid surface 16a Surroundings 16b Central part 18 First coil 22 Second Solenoid 24 Second Core 24b Non-magnetic part 26 Second Solenoid Surface 26a Surroundings 26b Central part 28 Second coil 30 valve spool 31 Spool body 32 first spool end 34 Second spool end 36 First permanent magnet 38 First Magnetic Surface 39 First cylindrical cup 40 processors 46 Second permanent magnet 48 Second Magnetic Surface 49 Second cylindrical cup 56 Valve body 60 First Fastener 62 Second Fastener 110 Four-way hydraulic valve 112 First Solenoid 114 First Core 114b Non-magnetic part 116 First solenoid surface 118 First Coil 122 Second Solenoid 124 Second Core 124b Non-magnetic part 126 Second Solenoid Surface 128 Second Coil 130 Valve spool 131 Spool body 132 first spool end 134 Second spool end 136 First permanent magnet 138 First Magnetic Surface 139 First cylindrical cup 140 processors 146 Second permanent magnet 148 Second Magnetic Surface 149 Second cylindrical cup 156 Valve body 160 First Fastener 162 Second Fastener 210 Hydraulic valve 212 First Solenoid 213 First coil cover 214 First Core 215 First coil plate 216 First Solenoid Surface 216a Surroundings 216b central part 218 First Coil 222 Second Solenoid 223 Second coil cover 224 Second Core 225 Second coil plate 226 Second Solenoid Surface 226a Surroundings 226b central part 228 Second Coil 230 Valve spool 231 Spool body 232 first spool end 234 Second spool end 236 First permanent magnet 238 First Magnetic Surface 239 First cylindrical cup 240 processors 242 First Plunger 244 First Sensor 244a First sensor plate 244b First limit switch 246 Second permanent magnet 248 Second Magnetic Surface 249 Second cylindrical cup 252 Second Plunger 254 Second Sensor 254a Second sensor plate 254b Second limit switch 256 Valve body 260 First Fastener 262 Second Fastener 264 The Third Magnet 266 The Fourth Magnet 268 The Fifth Magnet 270a First seal 270b Second seal 270c Third Seal 270d Fourth Seal 270e The Fifth Seal 270f Sixth Seal 272 First non-magnetic support 274 Second non-magnetic support 276 First Hydraulic Room 278 Second hydraulic chamber 280 First return flow path 282 Second return channel 300 Systems 310 Hydraulic valve 320 Pump 330 Hydraulic Fluid Reservoir 340 Controller 342 processor 344 Non-volatile memory 346 Volatile Memory 350 Actuator, Hydraulic Actuator 360 Controlled Components 400 aircraft 500 ways A1 Longitudinal axis A2 Longitudinal axis C Third Port C1 4th port C2 5th port F1 First flow path F2 Second flow path G1 First fluid flow path G2 Second fluid flow path G3 Third fluid flow path G4 Fourth fluid flow path H1 First flow path H2 Second flow path P Second port R First port R1 First port R2 3rd port

Claims

1. A valve body (56); a bistable valve spool (30) disposed within the valve body (56) and including a first permanent magnet (36) attached to a first spool end (32) of the valve spool (30) and a second permanent magnet (46) attached to a second spool end (34) of the valve spool (30); a first solenoid (12) disposed adjacent to the first spool end (32); a second solenoid (22) disposed adjacent the second spool end (34); a first plunger (242) and a first sensor (244) provided in the first solenoid (12); a second plunger (252) and a second sensor (254) provided in the second solenoid (22); A hydraulic valve (10) comprising: In a first mode of operation, the first solenoid (12) is energized with a first polarity that attracts the first permanent magnet (36) and the second solenoid (22) is energized with an opposite polarity that repels the second permanent magnet (46) to enable the first solenoid (12) and the second solenoid (22) to simultaneously push and pull the valve spool (30) between a first position and a second position; In the first position, a second magnetic surface (248) of the second permanent magnet (46) presses against the second plunger (252) with a second solenoid surface (226) of the second solenoid (22) to cause the second sensor (254) to detect the first position of the valve spool (30); In the second position, a first magnetic surface (238) of the first permanent magnet (36) presses against the first plunger (242) on a first solenoid surface (216) of the first solenoid (12) to cause the first sensor (244) to detect the second position of the valve spool (30).

2. 2. The hydraulic valve (10) of claim 1, wherein in a second mode of operation, the second solenoid (22) is energized to have the first polarity that attracts the second permanent magnet (46) and the first solenoid (12) is energized to have an opposite polarity that repels the first permanent magnet (36) to enable the first solenoid (12) and the second solenoid (22) to simultaneously pull the valve spool (30) between the second position and the first position.

3. 3. The hydraulic valve (10) of claim 1 or 2, wherein when the first solenoid (12) and the second solenoid (22) are de-energized, the first permanent magnet (36) is operable to maintain the valve spool (30) in the second position and the second permanent magnet (46) is operable to maintain the valve spool (30) in the first position.

4. the first solenoid (12) includes a first iron core (14) facing the first permanent magnet (36); the second solenoid (22) includes a second iron core (24) facing the second permanent magnet (46); In the first position, the first solenoid (12) is spaced apart from the first permanent magnet (36) and the second solenoid (22) is in contact with the second permanent magnet (46); In the second position, the second solenoid (22) is spaced apart from the second permanent magnet (46) and the first solenoid (12) is in contact with the first permanent magnet (36). A hydraulic valve (10) according to any one of claims 1 to 3.

5. the valve body (56) defining a first port (R), a second port (P), and a third port (C); In the first position, the valve spool (30) provides a first flow path (F1) between the second port (P) and the third port (C); In the second position, the valve spool (30) provides a second flow path (F2) between the first port (R) and the third port (C). A hydraulic valve (10) according to any one of claims 1 to 4.

6. a third magnet (264) disposed within the valve body (256) adjacent at least the flow passage and configured to magnetically attract ferrous particles in hydraulic fluid within the flow passage; A hydraulic valve (10, 210) according to any one of claims 1 to 5.

7. A method (500) for operating a bistable valve spool (30) of a hydraulic valve (10), the valve spool (30) including a first permanent magnet (36) disposed within a valve body (56) and attached to a first spool end (32) of the valve spool (30) and a second permanent magnet (46) attached to a second spool end (34) of the valve spool (30), the hydraulic valve (10) including a first solenoid (12) disposed adjacent to the first spool end (32) of the valve spool (30), a first plunger (242) and a first sensor (244) provided in the first solenoid (12), and a second permanent magnet (46) disposed adjacent to the second spool end (34) of the valve spool (30). a second solenoid (22) disposed in a first position and a second solenoid (22) and a second plunger (252) and a second sensor (254) disposed in the second solenoid (22), the first solenoid (12) and the second solenoid (22) being cooperatively operable to move the valve spool (30) to transition between a first position and a second position, when the first solenoid (12) and the second solenoid (22) are de-energized, the first permanent magnet (36) is operable to maintain the valve spool (30) in the second position, and the second permanent magnet (46) is operable to maintain the valve spool (30) in the first position, and the method (500) comprises: in response to receiving a first command to move the valve spool (30) from the second position to the first position, energizing the first solenoid (12) and the second solenoid (22) to move the valve spool (30) to the first position, wherein in the first position a second magnetic surface (248) of the second permanent magnet (46) presses against the second plunger (252) with a second solenoid surface (226) of the second solenoid (22) to cause a second sensor (254) to detect the first position of the valve spool (30); in response to receiving a second command to move the valve spool (30) from the first position to the second position, energizing the first solenoid (12) and the second solenoid (22) to move the valve spool (30) to the second position, where a first magnetic surface (238) of the first permanent magnet (36) pushes the first plunger (242) with a first solenoid surface (216) of the first solenoid (12) to cause a first sensor (244) to detect the second position of the valve spool (30); A method (500).

8. to place the valve spool (30) in the first position, the second solenoid (22) is excited to generate a second magnetic flux that attracts the second permanent magnet (46) to the second solenoid (22), and the first solenoid (12) is excited to generate a first magnetic flux that repels the first permanent magnet (36) from the first solenoid (12), and the valve spool (30) is maintained in the first position by a first magnetic force generated between the second solenoid (22) and the second permanent magnet (46); To place the valve spool (30) in a second position, the second solenoid (22) is excited to generate the second magnetic flux that repels the second permanent magnet (46) from the second solenoid (22), and the first solenoid (12) is excited to generate the first magnetic flux that attracts the first permanent magnet (36) to the first solenoid (12), and the valve spool (30) is maintained in the second position by a second magnetic force generated between the first solenoid (12) and the first permanent magnet (36).

8. The method of claim 7 (500).

9. In the first position, the flow of hydraulic fluid through a first port (R) of the valve body (56) is prevented by the valve spool (30) and a first flow path (F1) between a second port (P) and a third port (C) of the valve body (56) is enabled by the valve spool (30); 9. The method (500) of claim 7 or 8, wherein in the second position, a flow of hydraulic fluid through the second port (P) of the valve body (56) is stopped by the valve spool (30) and a second flow path (F2) between the first port (R) and the third port (C) of the valve body (56) is enabled by the valve spool (30).

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