JP7662944B2 - Solenoid device with position detection function - Google Patents

Description

The present disclosure relates to a solenoid device with a position detection function that can detect a first position, a second position, and an intermediate position.

Patent Document 1 describes a self-holding solenoid device that uses a permanent magnet to hold its position. Patent Document 1 also uses a reed switch to detect the distance to the permanent magnet. However, Patent Document 1 only opens and closes the valve and is unable to hold the valve in an intermediate position, and therefore is unable to detect that the valve is in an intermediate position.

Japanese Unexamined Patent Publication No. 58-89804

The objective of the present disclosure is to provide a solenoid device that can hold not only the first position and the second position, but also intermediate positions, and that has a position detection function that can detect whether it is in the first position, the second position, or the intermediate position.

The first aspect of the present disclosure includes a solenoid having a coil that is excited by energization, a stator core made of a magnetic material that forms a magnetic circuit when the coil is energized, a moving core made of a magnetic material that forms a magnetic circuit when the coil is energized and that moves to a first position, a second position, and an intermediate position between the first and second positions, a first permanent magnet that holds the moving core in the first position, and a second permanent magnet that holds the moving core in the second position.

The first aspect of the present disclosure includes a first magnetic sensor that detects the magnetic flux of either the first permanent magnet or the second permanent magnet when the moving core is in either the first position or the second position, and a second magnetic sensor that detects the magnetic flux of either the first permanent magnet or the second permanent magnet both at the position detected by the first magnetic sensor and at the intermediate position. When the moving core is held at the first position or the second position, no current is passed through the coil, and when the moving core is held at the intermediate position, current is passed through the coil.

According to the first aspect of the present disclosure, the first magnetic sensor detects the magnetic flux of either the first permanent magnet or the second permanent magnet, thereby making it possible to detect whether the valve is in the first position or the second position. Furthermore, the second magnetic sensor detects both the position detected by the first magnetic sensor and the intermediate position, thereby making it possible to detect that the moving core is held in the intermediate position. In the first aspect of the present disclosure, the position of the moving core can be determined based on the detection results.

In the second aspect of the present disclosure, the solenoid further includes a first member made of a magnetic material that faces the first permanent magnet in the first position and receives the attractive force of the first permanent magnet, and a second member made of a magnetic material that faces the second permanent magnet in the second position and receives the attractive force of the second permanent magnet. By arranging the first member and the second member, the first position and the second position can be more reliably held.

In the third aspect of the present disclosure, when the moving core is displaced in a direction from the first position toward the second position, current is passed through the coil in a first direction, and when the moving core is displaced in a direction from the second position toward the first position, current is passed through the coil in a second direction opposite to the first direction. The intermediate position is maintained by controlling the duty ratio of the timing at which current is passed through the coil in the first direction and the timing at which current is passed through the coil in the second direction. In the third aspect of the present disclosure, the duty ratio is used to maintain the intermediate position, and the second magnetic sensor is able to detect the magnetic flux of the coil at the intermediate position.

The fourth aspect of the present disclosure further includes a valve housing having an inlet passage through which the fluid flows, an outlet passage through which the fluid flows, and a valve seat disposed between the outlet passage and the inlet passage, and a valve that abuts against the valve seat in a second position to close the fluid flow, disengages from the valve seat in a first position to allow the maximum flow rate of the fluid, and allows a flow rate less than the maximum flow rate in an intermediate position. In the fourth aspect of the present disclosure, the flow rate of the fluid flowing through the valve housing can be detected by a position detection device.

FIG. 4 is a cross-sectional view showing a state in which the solenoid device is in a first position. FIG. 4 is a cross-sectional view showing a state in which the solenoid device is in a second position. 4 is a cross-sectional view showing the magnetic flux when the solenoid device moves from a first position to a second position. FIG. 4 is a cross-sectional view showing the magnetic flux when the solenoid device moves from the second position to the first position. FIG. 5A and 5B are diagrams illustrating the relationship between the magnetic force and stroke of a solenoid device. FIG. 4 is a cross-sectional view showing a state in which the solenoid device is in an intermediate position. 4A and 4B are diagrams illustrating the position of a permanent magnet and the detection state of a magnetic sensor.

The embodiment of the present disclosure is a solenoid device 100 shown in FIG. 1, which includes a coil 110. The coil 110 is formed by winding a large number of turns of enamel-coated copper wire around a coil bobbin made of resin such as polyphenylene sulfide resin (PPS). A stator core 120 is disposed on the inner circumference of the coil 110. The stator core 120 is made of a magnetic material, such as carbon steel.

The coil 110 is covered by an outer shell 130 made of resin such as polyphenylene sulfide resin (PPS). The outer shell 130 is formed integrally with a connector 131. A pair of terminals 136 are embedded in the connector 131 and are connected to the positive and negative sides of the coil 110, respectively. The terminal indicated by reference numeral 134 is a magnetic terminal of the first magnetic sensor 135, and the terminal indicated by reference numeral 133 is a magnetic terminal of the second magnetic sensor 137.

The stator core 120, which is disposed inside the coil 110, has a cylindrical shape, and the moving core 140 is disposed inside the cylindrical shape. Therefore, the moving core 140 can move inside the stator core 120. The moving core 140 is made of a magnetic material such as cold-rolled steel plate (SPCE). A disk-shaped first permanent magnet 151 is joined to one surface 141 (the upper end surface in FIG. 1) of the moving core 140. In addition, a ring-shaped second permanent magnet 152 is joined to the other surface 142 (the lower end surface in FIG. 1) of the moving core 140.

The magnetic pole of the first permanent magnet 151 facing one surface 141 of the moving core 140 and the magnetic pole of the second permanent magnet 152 facing the other surface 142 of the moving core 140 have the same polarity. In the example of Figures 1 and 2, the first permanent magnet 151 has a south pole on the top surface and a north pole on the bottom surface (the surface facing one surface 141 of the moving core 140). On the other hand, the second permanent magnet 152 has a north pole on the top surface (the surface facing the other surface 142 of the moving core 140) and a south pole on the bottom surface.

The yoke 125 is disposed from the outer periphery of the coil 110 to the portion facing the first permanent magnet 151. The yoke 125 is also made of a magnetic material such as iron. Therefore, the first permanent magnet 151 can be attracted to the yoke 125 by magnetic force. In this disclosure, the portion of the yoke 125 facing the first permanent magnet 151 becomes the first member 153.

The bottom of the cylindrical portion of the stator core 120 also faces the second permanent magnet 152 as shown in FIG. 2, and the second permanent magnet 152 can be attracted to the stator core 120 by magnetic force. In the present disclosure, the bottom of the cylindrical portion of the stator core 120 that faces the second permanent magnet 152 becomes the second member 154.

The middle part of the cylindrical part of the stator core 120 is formed to be thin-walled. Therefore, a first magnetic choke part 121 is formed on one surface 141 side of the moving core 140 from this middle part. Conversely, a second magnetic choke part 122 is formed on the other surface 142 side of the moving core 140 from the middle part. The moving core 140, the first permanent magnet 151, and the second permanent magnet 152 are held within the cylindrical part of the stator core 120.

The solenoid device 100 is configured as described above. The solenoid device 100 is coupled to the valve section 200. The valve section 200 is formed by a valve housing 210. The valve housing 210 is made of a non-magnetic material, for example, an aluminum alloy.

The valve housing 210 is formed with an inlet passage 222 through which various fluids flow depending on the application. As an example, in a heat pump system used in a vehicle air conditioner, it is possible to switch the flow of refrigerant between the second and first positions and to allow a predetermined flow rate to flow at an intermediate position. The valve housing 210 is formed with a valve chamber 225, which is connected to the inlet passage 222. The valve housing 210 is formed with an outlet passage 228 through which the inlet fluid flows out. Opposite the valve chamber 225 is formed a ring-shaped valve seat 229 which is connected to the outlet passage 228. The valve body 214 is disposed in the valve chamber 225 opposite the valve seat 229.

The valve body 214 has a valve body 217. The valve body 214 moves integrally with the moving core 140. A through hole 215 is formed in the center of the valve body 217, penetrating in the axial direction. A sheet 218 made of a rubber material such as ethylene propylene EPDM is disposed at the lower end of the valve body 214, facing the valve seat 229, and the sheet 218 is held to the valve body 217 by a washer 216. Therefore, the lower part of the valve body 214 is disc-shaped, and when the valve body 214 is seated on the valve seat 229, the seat 218 seals the valve seat 229. This blocks the flow of fluid between the valve body 214 and the valve seat 229.

The valve section 200 and solenoid device 100 configured as described above are assembled by placing the stator core 120 of the solenoid device 100 on top of the valve housing 210. The valve housing 210, which is made of a non-magnetic material, and the outer shell 130, which is made of resin, are joined together by screwing or the like.

Next, the operation of the solenoid device 100 of the present disclosure will be described. The state in which the first permanent magnet 151 is attracted to the first member 153 as shown in FIG. 1 is defined as the first position, and the state in which the second permanent magnet 152 is attracted to the second member 154 as shown in FIG. 2 is defined as the second position. First, the holding of the first and second positions will be described.

The state in which the moving core 140 holds the first position is maintained solely by the magnetic attraction force of the first permanent magnet 151, without current being applied to the coil 110. In this first position, the valve body 214 is in a fully open position where it is separated from the valve seat 229. Therefore, the fluid that has flowed from the inlet passage 222 into the valve chamber 225 flows at a maximum rate from the valve seat 229 to the outlet passage 228. This makes it possible to maintain a state in which the entire amount of fluid flows out without current being applied to the coil 110.

The moving core 140 maintains the second position in the same manner. That is, the coil 110 is not energized, and is maintained in contact with the second member solely by the magnetic attraction of the second permanent magnet 152. In this second position, the valve body 214 is seated on the valve seat 229. Therefore, the valve body 214 is in a fully closed position, and the fluid that has flowed from the inlet passage 222 into the valve chamber 225 is blocked by the valve body 214 and the valve seat 229, and does not flow into the outlet passage 228. This makes it possible to maintain the fluid blocking state without energizing the coil 110.

When moving from the first position to the second position, as shown in FIG. 3, current is passed through the coil 110 in the first direction, and the leakage magnetic flux between the second magnetic restricting portion 122 of the stator core 120 and the second permanent magnet 152 and moving core 140 attracts the moving core 140. The magnetic flux at this time is directed in a direction that repels the first permanent magnet 151. Conversely, the magnetic flux is directed in a direction that attracts the second permanent magnet 152. Therefore, the magnetic force required to move the moving core 140 can be compensated for by the first permanent magnet 151 and the second permanent magnet 152. In other words, it is possible to reduce the size of the coil 110 required to move the moving core 140.

When the moving core 140 moves to the second position, as described above, the current supply to the coil 110 is terminated, and the state of the second position is maintained by the second permanent magnet 152. When the moving core 140 is moved in a direction from the second position toward the first position, the coil 110 is energized, and the moving core 140 is attracted by the leakage magnetic flux between the first magnetic restricting portion 121 of the stator core 120 and the first permanent magnet 151 and the moving core 140. The current supply direction to the coil 110 at this time is the second direction opposite to the first direction. Therefore, as shown in FIG. 4, the magnetic flux direction is a mutually attracting direction in the first permanent magnet 151, and a mutually repelling direction in the second permanent magnet 152. Therefore, even when the moving core 140 is moved in a direction from the second position toward the first position, the magnetic force required for the movement of the moving core 140 can be supplemented by the first permanent magnet 151 and the second permanent magnet 152.
The through hole 215 is a hole that serves as a pilot flow path, through which the fluid flows when the moving core 140 moves from the second position to the first position and displaces the valve body 214. This eliminates the difference in fluid pressure above and below the valve body 214, and the urging force of the spring 219 allows the valve body to move smoothly upward (from the second position to the first position).

Figures 3 and 4 show the magnetic circuit diagrammatically, and the portion of the moving core 140 that connects to the valve body 214 is omitted. However, as shown in Figures 3 and 4, it is possible for the first member 153 to be a separate member from the yoke 125. Similarly, it is possible for the second member 154 to be a separate member from the stator core 120. If the stator core 120 is cylindrical with a closed upper portion, it is also possible for the first member 153 to be formed from the stator core 120.

Figure 5 is an explanatory diagram explaining the above-mentioned positions of the moving core 140 and the energized state of the coil 110. In Figure 5, point D indicates the state in which the moving core 140 is held in the first position. The attractive force in this state is the magnetic force of the first permanent magnet 151 attracting the first member 153. Movement from the first position to the second position is indicated by line F. In this state, a voltage in the first direction is applied to the coil 110. In Figure 5, the first direction is indicated by -. Point G is the state in which the second position is reached. In this state of point G, the second position is maintained by the excitation force of the coil 110.

The state when the application of the voltage in the first direction to the coil 110 ends at the second position is point H. After point G, the stroke of the second position is maintained at point H by the attractive force of the second permanent magnet 152. Movement from the second position to the first position is shown by line B. In the state of line B, a voltage in the second direction is applied to the coil 110. In FIG. 5, the second direction is represented by +. The state when the first position is reached is point C. The state of point C is the opposite of point G, and the first position is maintained by the excitation force of the coil 110. Then, the state when the application of the voltage in the second direction to the coil 110 ends at the first position is point D, and thereafter the initial point D is maintained by the attractive force of the first permanent magnet 151.

Next, the intermediate position between the first position (FIG. 1) and the second position (FIG. 2) will be described. FIG. 6 shows the state in which the moving core 140 is in the intermediate position. The intermediate position is obtained by repeating a state in which the coil 110 is energized in the first direction and a state in which the coil 110 is energized in the second direction at a cycle of about 100 Hz and a duty ratio of 50%. While the first and second positions described above are maintained in a state in which no current is applied to the coil 110, the intermediate position is achieved by controlling the current to be applied to the coil 110 to be switched between the first and second directions. That is, when the moving core 140 is held in the intermediate position, current is applied to the coil 110, and the coil 110 is repeatedly excited in the first direction and the second direction.

Next, the position detection of the moving core 140 will be described. As described above, no current is applied to the coil 110 whether the moving core 140 is maintained in the first position or in the second position. Therefore, it is difficult to determine whether the coil 110 is in the first position or the second position by the current being applied to the coil 110 without using a memory or the like. In this example, the position detection of the moving core 140 is performed by the first magnetic sensor 135 and the second magnetic sensor 137.

The first magnetic sensor 135 is positioned to detect the magnetic force of the first permanent magnet 151 when the first permanent magnet 151 is in the first position. The first magnetic sensor 135 is also magnetically shielded from the magnetic field of the coil 110. More specifically, the magnetic field of the coil 110 flows through the moving core 140 and the yoke 125, and does not leak to the resin outer casing 130, or even if there is magnetic leakage, it is very small. In contrast, as shown in FIG. 3, the magnetic field of the first permanent magnet 151 leaks to the outer casing 130 side separately from the magnetic field of the coil 110. The first magnetic sensor 135 detects the leaked magnetic flux of this first permanent magnet 151.

The first magnetic sensor 135 is a reed switch, magnetic pickup sensor, or Hall sensor that outputs a signal when it detects a magnetic force. In this example, a reed switch is used. Therefore, if a signal from the first magnetic sensor 135 is detected, it can be confirmed that the moving core 140 and valve body 214 are in the first position. In other words, if a signal from the first magnetic sensor 135 is not detected, the moving core 140 and valve body 214 are in the second position or an intermediate position.

The second magnetic sensor 137 is disposed at a position where it detects the magnetic force of the first permanent magnet 151 when the first permanent magnet 151 is in both the first position and the intermediate position. As described above, the magnetic force of the first permanent magnet 151 leaks out to the outer casing 130 in large amounts in the first position shown in FIG. 3. Conversely, in the second position shown in FIG. 4, the magnetic force of the first permanent magnet 151 hardly leaks out to the outer casing 130 side. FIG. 7 shows the magnetic force of the first permanent magnet 151 leaking out to the outer casing 130 side. In FIG. 7, in order to make it easier to understand the range of the magnetic force of the first permanent magnet 151, the first permanent magnet 151 is fixed, and the first magnetic sensor 135 and the second magnetic sensor 137 are drawn to move between the first position, the intermediate position, and the second position. The area indicated by A in FIG. 7 is the area where the first magnetic sensor 135 and the second magnetic sensor 137 detect the magnetic force and output an "on" signal. There is a hold area B around area A, and outside of the hold area B is area C, where the first magnetic sensor 135 and the second magnetic sensor 137 no longer detect magnetism and the output is "off."

The second magnetic sensor 137 is disposed at a position that is included in the area A of the first permanent magnet 151 at the first position and the intermediate position. And, like the first magnetic sensor 135, the second magnetic sensor 137 is also magnetically shielded from the magnetic field of the coil 110. The second magnetic sensor 137 is also a reed switch, a magnetic pickup sensor, or a Hall sensor that outputs a signal when it detects a magnetic force, and in this example, a reed switch is used. Therefore, in FIG. 7, the first magnetic sensor 135 and the second magnetic sensor 137 are depicted as reed switches. If a signal from the second magnetic sensor 137 is detected, it can be confirmed that the moving core 140 and the valve body 214 are in either the first position or the intermediate position. In other words, if a signal from the second magnetic sensor 137 is detected, there is a possibility that the moving core 140 and the valve body 214 are in the intermediate position.

By using the first magnetic sensor 135 and the second magnetic sensor 137, it is possible to detect the position of the solenoid device 100 (moving core 140), and a solenoid device with a position detection function can be provided. The first magnetic sensor 135 detects the magnetic force of the first permanent magnet 151 in the first position. Therefore, when the moving core 140 and the valve body 214 are held in the first position, the first magnetic sensor 135 turns "on" in magnetic detection. In this first position, the second magnetic sensor 137 also detects the magnetism of the first permanent magnet 151 and turns "on."

Conversely, when the moving core 140 and the valve body 214 are held in the second position, the first magnetic sensor 135 does not detect the magnetism of the first permanent magnet 151 and is "off," and the second magnetic sensor 137 also does not detect the magnetism and is "off." And, when the moving core 140 and the valve body 214 are in the intermediate position, the first magnetic sensor 135 does not detect the magnetism of the first permanent magnet 151 and is "off," but the second magnetic sensor 137 detects the magnetism of the first permanent magnet 151 and is "on."

The position of the valve body 214 can be confirmed from the flow of the fluid, so if there is a discrepancy between the fluid flow and the signals from the first magnetic sensor 135 and the second magnetic sensor 137, an abnormality in the solenoid device 100 can be detected. Not only that, but it is also possible to infer in which position the solenoid device 100 is located. For example, when the solenoid device 100 is in the first position, the first magnetic sensor 135 should be "on" by detecting the magnetism of the first permanent magnet 151, but it is outputting an "off" signal. In that case, if the second magnetic sensor 137 is "on", it can be inferred that the solenoid device 100 is in the intermediate position, and if the second magnetic sensor 137 is "off", it can be inferred that the solenoid device 100 is stuck in the second position. In that case, the coil 110 can be energized in the first direction to return the moving core 140 and the valve body 214 to the first position.

When in the second position, the first magnetic sensor 135 and the second magnetic sensor 137 should not detect the magnetism of the first permanent magnet 151 and should output an "off" signal. However, if the first magnetic sensor 135 and the second magnetic sensor 137 both output an "on" signal, it can be assumed that they are stuck in the first position. In that case, the moving core 140 and the valve body 214 can be returned to the second position by passing electricity through the coil 110 in the second direction, in the opposite manner to the above.

Even if the first magnetic sensor 135 outputs an "on" signal when in the intermediate position, it can be assumed that they are stuck in the first position, so current is passed through the coil 110 in the second direction to pull the moving core 140 and valve body 214 back from the first position. Conversely, if the first magnetic sensor 135 outputs an "off" signal when in the intermediate position, it can be assumed that they are stuck in the second position, so current is passed through the coil 110 in the first direction to pull the moving core 140 and valve body 214 back from the second position.

As explained above, the first and second positions are held by the first permanent magnet 151 and the second permanent magnet 152. Therefore, there is a risk that the moving core 140 may move to the second position when it should be in the first position. Similarly, there is a risk that the coil 110 may become stuck in the first or second position even though it should be in an intermediate position by controlling the duty ratio of the current passing through the coil 110. In this way, it is conceivable that the moving core 140 may move to a position other than the originally intended position due to the influence of external vibrations, etc. In that case, a signal is again sent to the coil 110 to move the moving core 140 to the position where it should be.

The above example is a preferred embodiment of the present disclosure, but the present disclosure includes various other embodiments. For example, in the above example, the valve housing 210 is constructed as a single unit, but it may be separated into an upper body and a lower body. In that case, the two components are fixed using a fixing method such as welding, bolt fixing, or clip fastening. The valve housing 210 may also be constructed of three or more components.

In the above example, the valve body 214 is shaped like a flat plate that comes into and out of contact with the valve seat 229, but the valve body 214 may be shaped to fit into the valve seat 229. The flow rate of the fluid may be made variable depending on the distance between the valve body 214 and the valve seat 229. In that case, the duty ratio is not fixed to 50%, and the flow rate can be controlled depending on the duty ratio. The intermediate position of the present disclosure may be between the first position and the second position.

The positions of the first magnetic sensor 135 and the second magnetic sensor 137 are not limited to positions where the magnetic force of the first permanent magnet 151 is detected when the first permanent magnet 151 is in the first position. They may be located in positions where the magnetic force of the first permanent magnet 151 is detected when the first permanent magnet 151 is in the second position. Similarly, they may be located in positions where the magnetic force of the second permanent magnet 152 is detected when the second permanent magnet 152 is in the first position, and may be located in positions where the magnetic force of the second permanent magnet 152 is detected when the second permanent magnet 152 is in the second position. In any case, it is sufficient to be able to determine whether the first position, the intermediate position, or the second position is detected by detecting the magnetic force of either the first permanent magnet 151 or the second permanent magnet 152.

In the above example, the solenoid device 100 is used as a valve that opens and closes the valve seat 229, but it may also be used for various actuators. Any actuator that can be driven to the first position, the second position, and an intermediate position can be used. According to the present disclosure, even if the solenoid device 100 is used for various purposes, the position can be detected correctly.

The above-mentioned materials are merely examples, and the present invention is not limited to the materials described. The disclosure in this specification and drawings is not limited to the illustrated embodiments. The disclosure includes the illustrated embodiments and variations thereon by those skilled in the art.

REFERENCE SIGNS LIST 100 Solenoid device 110 Coil 135 First magnetic sensor 137 Second magnetic sensor 140 Moving core 151 First permanent magnet 152 Second permanent magnet 214 Valve body

Claims (4)

a solenoid having a coil which is excited when current is passed through it, a stator core made of a magnetic material which forms a magnetic circuit when current is passed through the coil, a moving core made of a magnetic material which forms a magnetic circuit when current is passed through the coil and which moves to a first position, a second position, and an intermediate position between the first position and the second position, a first permanent magnet which holds the moving core at the first position, and a second permanent magnet which holds the moving core at the second position;
a first magnetic sensor that detects a magnetic flux of at least one of the first permanent magnet and the second permanent magnet when the moving core is located at the first position or the second position;
a second magnetic sensor that detects magnetic flux of at least one of the first permanent magnet and the second permanent magnet at a position detected by the first magnetic sensor and the intermediate position,
a solenoid device with a position detection function, characterized in that when the moving core is held at the first position and the second position, no current is applied to the coil, and when the moving core is held at the intermediate position, current is applied to the coil. 2. The solenoid device with position detection function according to claim 1, characterized in that the solenoid further comprises a first member made of a magnetic material that faces the first permanent magnet at the first position and receives the attractive force of the first permanent magnet, and a second member made of a magnetic material that faces the second permanent magnet at the second position and receives the attractive force of the second permanent magnet. When the moving core is displaced in a direction from the first position toward the second position, a current is passed through the coil in a first direction, and when the moving core is displaced in a direction from the second position toward the first position, a current is passed through the coil in a second direction opposite to the first direction,
3. The solenoid device with position detection function according to claim 1, wherein the intermediate position is maintained by controlling a duty ratio of a timing at which current is passed through the coil in the first direction and a timing at which current is passed through the coil in the second direction. a valve housing having an inlet passage through which a fluid flows, an outlet passage through which the fluid flows out, and a valve seat disposed between the outlet passage and the inlet passage;
4. The solenoid device with position detection function according to claim 1, further comprising a valve that abuts against the valve seat to close the flow of fluid in the second position, disengages from the valve seat to allow a maximum flow rate of fluid in the first position, and allows a flow rate less than the maximum flow rate of fluid in the intermediate position.

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