JP7553808B2 - Solenoid valve - Google Patents

Description

This disclosure relates to an electromagnetic valve that opens and closes the flow path of a working fluid, and is suitable for use, for example, in controlling the flow path of washer fluid.

The inventors previously proposed a solenoid valve used to switch the flow path of washer fluid, etc., referring to Patent Document 1 as a prior art document (Patent Application No. 2020-44325, Patent Application No. 2020-44326). The solenoid valve proposed by the inventors allows the size of the solenoid part to be reduced, but on the other hand, it could not be denied that when the valve seat is open, the flow rate of the working fluid increases as it flows through the narrow space between the valve seat and the valve body, and the fluid pressure downstream of the valve body may decrease.

To keep the valve disc separated from the valve seat even when the fluid pressure downstream of the valve seat drops, a spring that maintains a pressing force equal to or greater than a certain load must be applied to the valve disc. As a result, the excitation force of the coil required to move the valve disc and plunger must also be greater than the biasing force of the spring. This ultimately means that the size of the solenoid valve, including the coil, must also increase, posing a challenge in further miniaturization efforts.

JP 2014-66309 A

In view of the above, the present disclosure aims to provide a solenoid valve that can suppress the pressure drop of the working fluid downstream of the valve seat and maintain the valve body separated from the valve seat with a smaller spring pressure.

The first aspect of the present disclosure includes a coil that is excited when energized, a core made of a magnetic material that is placed in the magnetic circuit of the coil when energized, a plunger that is placed opposite the core across a magnetic gap in the magnetic circuit of the coil when energized, and a valve body that comes into contact with the plunger and moves integrally with the plunger.

The first aspect of the present disclosure also includes a valve body having an inlet passage for the working fluid, an outlet passage for the working fluid, a valve seat formed between the inlet passage and the outlet passage against which the valve body abuts, a valve chamber formed between the valve seat and the inlet passage, and a pressure chamber formed between the valve seat and the outlet passage.

In the first aspect of the present disclosure, a normally-closed compression spring is provided that comes into contact with the plunger and urges the plunger in a direction away from the core and in a direction toward the valve seat, and a normally-open compression spring is provided that comes into contact with the valve seat and urges the valve body in a direction away from the valve seat. When the valve body leaves the valve seat and the working fluid flows from the valve chamber into the pressure chamber, the fluid flow is impeded in the pressure chamber, causing pressure recovery.

When the valve disc separates from the valve seat, there is a concern that the working fluid flowing from the valve chamber into the pressure chamber will increase in flow rate as it flows through the gap between the valve seat and the valve disc, resulting in a drop in pressure downstream of the valve disc. However, in the first aspect of the present disclosure, the pressure chamber is formed directly below the valve disc by a flow path restriction portion arranged in the outflow passage, and the fluid flow is obstructed at the flow path restriction portion of the pressure chamber, so that pressure can be restored and the pressure drop directly below the valve disc can be reduced .

This reduces the force pulling the valve body toward the valve seat, and also reduces the spring pressure that keeps the valve body open. This in turn reduces the excitation force of the coil that moves the plunger and valve body against the spring pressure. As a result, the spring and coil can be made smaller, making it possible to further reduce the size of the solenoid valve.

In the first aspect of the present disclosure, a flow path throttle portion is formed in the pressure chamber to provide flow resistance to the working fluid flowing through the outflow passage. The flow path throttle portion obstructs the flow of the working fluid, which increases in flow velocity when flowing through the gap between the valve seat and the valve body and has its pressure reduced downstream of the valve body. This allows the pressure of the working fluid in the pressure chamber to be restored.

In the present disclosure, the flow passage throttle portion is integrally molded with the valve body, which makes it possible to prevent an increase in the number of parts.

In another aspect of the present disclosure, the flow passage throttle portion is formed in a flow passage throttle member, and this flow passage throttle member is disposed in the valve body to form a pressure chamber. Although the number of parts increases due to the provision of the flow passage throttle member, the flow passage throttle portion is easily formed.

In another aspect of the present disclosure, the valve body is spherical with a ring-shaped spring bearing formed at the equator, and the plunger abuts on the central axis of the valve body, and the normally open compression spring abuts on the spring bearing of the valve body.

By making the valve disc spherical, sealing can be ensured even if the valve disc is tilted slightly. As a result, the solenoid valve can be constructed simply, contributing to miniaturization.

In another aspect of the present disclosure, the valve body is provided with a second outflow passage communicating with the valve chamber, and a second valve seat formed between the second outflow passage and the valve chamber. The second valve seat faces the valve seat, and when the valve disc is in contact with the valve seat, the valve disc is separated from the second valve seat, and when the valve disc is separated from the valve seat, the valve disc is in contact with the second valve seat.

According to another aspect of the present disclosure, the valve can function as a three-way valve that switches the working fluid that has flowed in from the inlet passage between the outlet passage side and the second outlet passage side.

In another embodiment of the present disclosure, the valve seat is a normally closed valve seat with which the valve body contacts when the coil is de-energized, and the second valve seat is a normally open valve seat with which the valve body disengages when the coil is de-energized. The three-way valve can be used as a valve in which the outflow passage is closed when the coil is de-energized.

In another aspect of the present disclosure, the valve body is spherical, and a normally closed valve seat and a normally open valve seat are disposed opposite each other, both of which are arc-shaped corresponding to the spherical shape of the valve body. This improves the sealing performance between the normally closed valve seat and the normally open valve seat and the valve body in a three-way valve.

FIG. 2 is a diagram illustrating a piping configuration of a solenoid valve. FIG. 2 is a cross-sectional view of the solenoid valve according to the first embodiment. FIG. 3 is a perspective view of the solenoid valve shown in FIG. 2 . FIG. 3 is a cross-sectional view showing a pressure chamber of the solenoid valve shown in FIG. 2 . FIG. 3 is a perspective view of the valve body shown in FIG. 2 . FIG. 3 is a perspective view of the pressure relief valve body shown in FIG. 2 . FIG. 6 is a cross-sectional view of a solenoid valve according to a second embodiment. FIG. 11 is a cross-sectional view of a solenoid valve according to a third embodiment. FIG. 9 is a cross-sectional view of the flow passage restrictor member shown in FIG. 8 . FIG. 9 is a perspective view of the flow passage restricting member shown in FIG. 8 . FIG. 11 is a perspective view showing another shape of the valve body. FIG. 13 is a perspective view of a flow passage restricting member according to a fourth embodiment.

First Embodiment
In the first embodiment, the pipes 102 are arranged as shown in Fig. 1, and a three-way valve that switches the flow path is used as the solenoid valve 200. The nozzle 100 of the normally closed pipe 102a faces the rear window glass 130 and sprays the washer fluid onto the rear window glass 130. The nozzle of the normally open pipe 102b sprays the washer fluid onto the camera 131. In the present disclosure, when the solenoid valve 200 is not energized, the washer fluid from the pump 120 is sprayed onto the camera 131. This is because the camera 131 is used more frequently than the rear window glass 130.

As shown in Figures 2 and 3, the solenoid valve 200 has a coil 205 made of copper wire wound many times around a resin coil bobbin 204. A stator 211 is arranged on the inner circumference of the coil bobbin 204 via a sleeve 210. The sleeve 210 is made of a non-magnetic material, such as SUS304. On the other hand, the stator 211 is made of a magnetic material, such as SUS430.

The outer circumference of the coil bobbin 204 is covered by a resin outer shell 220. The outer shell 220 is formed integrally with the connector 202. A pair of terminals 221 are embedded and molded in the connector 202, and the pair of terminals 221 are connected to the positive and negative sides of the coil 205, respectively.

A core 206 made of a magnetic material is placed inside the coil bobbin 204. The core 206 has a cylindrical shape with a closed upper end and a tapered open end.

The plunger 209 is disposed facing the tapered portion of the core 206. The plunger 209 is cylindrical, with a tapered upper end that corresponds to the tapered shape of the core 206. The plunger 209 has a shoulder 209a that continues from the tapered upper end, and a washer engages with this shoulder 209a. The washer is made of a non-magnetic material such as SUS304, and prevents the magnetic core 206 and plunger 209 from remaining attracted to each other due to residual magnetic force after the current is turned off. The plunger 209 is guided by the cylindrical portion 211a of the stator 211 and moves in the vertical direction in FIG. 2.

A normally closed compression spring 207 is disposed within the core 206, which biases the plunger 209 in a direction that pulls it away from the core 206. A yoke 201 is disposed on the outer periphery of the outer shell 220 of the coil bobbin 204. The yoke 201 is made of magnetic steel, and when a current is applied to the coil 205, a magnetic circuit is formed by this yoke 201, the core 206, the plunger 209, and the stator 211.

The electromagnetic part 230 is configured as described above. This electromagnetic part 230 is connected to the flow passage part 250 via an O-ring 213. The flow passage part 250 includes a valve body, which is divided into an upper body 212 and a lower body 219.

The upper body 212 is formed with an inlet passage 222 through which high-pressure washer fluid from the pump 120 flows in, and a normally open outlet passage 223 that is connected to the normally open pipe 102b that leads to the camera 131. This normally open outlet passage 223 corresponds to the second outlet passage. The outer periphery of the ends of the inlet passage 222 and the normally open outlet passage 223 is tapered to facilitate connection of the pipe 102. A shoulder 224 is formed at the tapered end to prevent the pipe 102 from coming loose.

A valve chamber 225 is formed in the upper body 212, and the valve chamber 225 communicates with the inlet passage 222 via a communication hole 226. The valve chamber 225 also communicates with the normally open outlet passage 223 via a normally open valve seat 227. This normally open valve seat 227 corresponds to the second valve seat.

A connection part 251 with the electromagnetic part 230 is formed at the top of the upper body 212. The connection part 251 has a cylindrical shape, and the plunger 209 is disposed inside. The top of the connection part 251 also widens to form an upper surface 252 that receives the O-ring 213, and also forms a locking shoulder 253 that locks with the yoke 201.

A normally closed outflow passage 228 is formed in the lower body 219, which is connected to the normally closed piping 102a leading to the rear window glass 130. This normally closed outflow passage 228 corresponds to the outflow passage. The end of the normally closed outflow passage 228 is tapered, and a shoulder 224 is formed, similar to the inflow passage 222 described above. This normally closed outflow passage 228, the inflow passage 222, and the normally open outflow passage 223 all have an inner diameter of about 3 millimeters.

The lower body 219 is formed with a cylindrical normally closed valve seat 229 that protrudes into the valve chamber 225. This normally closed valve seat 229 corresponds to the valve seat. A spherical valve body 214 is disposed in the valve chamber 225 between the normally open valve seat 227 and the normally closed valve seat 229. The normally open valve seat 227 and the normally closed valve seat 229 are tapered, and both have an inner diameter of just under 5 millimeters.

A pressure chamber 240 is formed downstream of the normally closed valve seat 229 of the lower body 219. As shown in FIG. 4, the pressure chamber 240 is formed on the inner circumference of the cylindrical normally closed valve seat 229, and a flow path restrictor 241 is formed between the pressure chamber 240 and the normally closed outflow passage 228. Therefore, the washer fluid that flows into the pressure chamber 240 flows out from the flow path restrictor 241 provided on the inner circumference of the flow path restrictor 241 to the normally closed outflow passage 228. The flow path restrictor 241 is a hole with an inner diameter of about 2 millimeters.

As shown in Figure 5, the valve body 214 is spherical with a diameter of just over 7 mm, and the annular spring retainer 214a protrudes just under 1 mm at the equator. The valve body 214 and the spring retainer 214a are integrally molded from water-resistant rubber, and the surface is coated. This rubber material is the same as that of the O-ring 213. The coating material is a substance such as fluorine or molybdenum that prevents the rubber surface from melting and improves the seating ability of the valve body and the mating valve seat.

A normally open compression spring 231 is disposed on the outer periphery of the cylindrical normally closed valve seat 229. The inner diameter of this normally open compression spring 231 is slightly larger than the outer diameter of the normally closed valve seat 229, and is held by the outer periphery of the normally closed valve seat 229. This normally open compression spring 231 engages with the spring receiver 214a of the valve body 214, and biases the valve body 214 toward the normally open valve seat 227.

As a result, the valve body 214 is subjected to both the biasing force of the normally closed compression spring 207 and the biasing force of the normally open compression spring 231, which are received via the plunger 209. Since the biasing force of the normally closed compression spring 207 is sufficiently greater than the biasing force of the normally open compression spring 231, when the coil 205 is not energized, the valve body 214 is pressed against the normally closed valve seat 229, closing the normally closed outflow passage 228.

The lower body 219 is formed with a pressure relief passage 232 that bypasses the normally closed valve seat 229 and connects the inlet passage 222 to the normally closed outlet passage 228. The upper body 212 is also formed with a pressure relief passage 232. The inner diameter of the pressure relief passage 232 is approximately 2 millimeters.

A pressure relief valve 233 that opens and closes this pressure relief passage 232 is disposed in the upper body 212. The pressure relief valve 233 is composed of a pressure relief valve seat 218, a pressure relief valve body 217, and a pressure relief spring 216. The pressure relief valve seat 218 is made of a rubber material with a fluorine-coated surface, similar to the valve body 214, and is sandwiched between the upper body 212 and the lower body 219.

The pressure relief valve body 217 is made of resin, has a cylindrical shape, and can move along the pressure relief guide 234 formed in the upper body 212. Both the outer diameter of the pressure relief valve body 217 and the inner diameter of the pressure relief guide 234 are just over 5 millimeters.

As shown in FIG. 6, three pressure relief grooves 217a are formed on the outer periphery of the pressure relief valve body 217. The pressure relief grooves 217a are semicircular with a radius of about 0.3 mm. A cylindrical pressure relief spring support 217b that supports the pressure relief spring 216 is formed on the upper surface of the pressure relief valve body 217.

The pressure relief spring 216 is therefore clamped between this pressure relief spring receiver 217b and a spring receiver formed at the lower end of the pressure relief passage 232 of the upper body 212, pressing the pressure relief valve body 217 towards the pressure relief valve seat 218. The set pressure (relief pressure) of this pressure relief spring 216 is about 5 kilopascals, which is about half the set pressure (release pressure) of the stop valve 101.

Next, we will explain how to assemble the solenoid valve 200 with the above structure.

First, the electromagnetic section 230 will be described. The coil 205 is wound many times around the outer circumference of the coil bobbin 204, and a pair of terminals 221 are connected to both ends of the coil 205. In this state, the outer casing 220 and the connector 202 are molded with resin. For example, polyphenylene sulfite is used as the resin. Next, the core 206 and the stator 211 are disposed on the inner circumference of the coil bobbin 204 via the sleeve 210. After that, the yoke 201 is disposed on the outer circumference of the outer casing 220.

After placing the O-ring 213 on the top surface 252 of the upper body 212, placing the normally closed compression spring 207 inside the core 206, and placing the plunger 209 on the inner diameter of the stator 211, the lower end of the yoke 201 is crimped toward the locking shoulder 253 of the upper body 212. The crimping is performed around the entire circumference of the yoke 201 except for the part where the connector 202 is located.

By crimping this yoke 201, the upper end of the upper body 212 comes into contact with the lower end of the stator 211, and the O-ring 213 is compressed and deformed by the lower end of the stator 211 and the upper surface 252 of the upper body 212.

The flow path section 250 places the pressure relief spring 216 and pressure relief valve body 217 in the pressure relief guide 234 of the upper body 212. Then, the pressure relief valve seat 218 is placed in the opening of the pressure relief guide 234. In addition, the valve body 214 is placed on the normally open valve seat 227, and the normally open compression spring 231 is placed so that it abuts against the spring receiver 214a.

In this state, the flange 212a of the upper body 212 and the flange 219a of the lower body 219 are brought into contact and welded together.

According to the present disclosure, since the flow passage portion 250 is assembled after assembling the electromagnetic portion 230, the shape of the parts from the upper body 212 onwards can be selected, and the electromagnetic portion 230 can be standardized. As will be explained in the second embodiment and onwards, the flow passage portion 250 may change the directions of the inlet passage 222, the normally open outlet passage 223, and the normally closed outlet passage 228. Furthermore, the normally open outlet passage 223 or the normally closed outlet passage 228 may be eliminated to form a two-way valve. Even if the flow passage portion 250 is changed in this way, the same electromagnetic portion 230 can be commonly used.

According to the present disclosure, the plunger 209 and the valve body 214 are separated, the plunger 209 is disposed in the electromagnetic part 230, and the valve body 214 is disposed in the flow path part 250. Therefore, it is possible to assemble the flow path part 250 after assembling the electromagnetic part 230 as described above, and the ease of assembly is also improved.

Next, the operation of the solenoid valve 200 of the present disclosure will be described.

When the washer fluid is sprayed from the nozzle 100 toward the camera 131, the solenoid valve 200 is not energized. Therefore, the biasing force of the normally closed compression spring 207 is applied to the valve body 214 via the plunger 209, closing the normally closed valve seat 229.

When the pump 120 starts operating, high-pressure washer fluid is sent to the solenoid valve 200 via the pipe 102. The sent washer fluid flows into the inlet passage 222, and then flows out of the normally open outlet passage 223 via the communication hole 226, the valve chamber 225, and the normally open valve seat 227.

During this time, the valve body 214 is pressed against the normally closed valve seat 229 by the pressure of the normally closed compression spring 207 and the pressure of the washer fluid. Even if the position of the valve body 214 is slightly misaligned, the abutment surface of the valve body 214 with the normally closed valve seat 229 is spherical, and the normally closed valve seat 229 is tapered, so that the valve body 214 is always guided in a direction in which the central axes are aligned. Therefore, the valve body 214 is securely abutted against the normally closed valve seat 229, providing sufficient sealing performance.

The washer fluid that passes through the solenoid valve 200 is sprayed from the nozzle 100 via the normally open pipe 102b. The pressure of the washer fluid rises to about 400 kilopascals, so the release pressure of the stop valve 101 (about 10 kilopascals) is of little concern.

When the cleaning of the camera 131 is completed, the pump 120 is stopped. When the pump is stopped, the pressure in the pipe 102 becomes atmospheric pressure, so the pipe 102 is closed by the stop valve 101. Closing the stop valve 101 improves the liquid drainage when the spray ends. In addition, the washer fluid can be stored in the pipe 102, improving responsiveness the next time it is activated.

When spraying washer fluid onto the rear window glass 130, electricity is applied to the solenoid valve 200. When electricity is applied, the coil 205 is excited, and a magnetic circuit is formed in the yoke 201, the core 206, the plunger 209, and the stator 211. The magnetic gap between the tapered portion of the core 206 and the tapered portion of the plunger 209 is narrowed by the magnetic force, and the plunger 209 moves toward the core 206 against the compression force of the normal close compression spring 207.

As the plunger 209 moves, the valve body 214 is pushed up by the normally open compression spring 231, closing the normally open valve seat 227. Note that the above operation of the solenoid valve 200 is performed before the pump 120 starts operating. Therefore, the high-pressure washer fluid pressure from the pump 120 is not applied to the valve body 214, and the movement of the valve body 214 is not impeded.

Here, since the plunger 209 is structured to detachably abut against the spherical portion of the valve body 214, the valve body 214 may shift slightly when the plunger 209 moves. In other words, the present disclosure is a configuration that allows for some shifting of the valve body 214. However, since the valve body 214 is spherical and the normally open valve seat 227 also has a tapered shape corresponding to the valve body 214, the normally open valve seat 227 can be reliably sealed even if it shifts slightly as the normally open compression spring 231 expands. In particular, since the valve body 214 is made of rubber, it can adhere closely to the normally open valve seat 227 due to its own elasticity, further improving the sealing performance.

In addition, since the normal-open compression spring 231 abuts against the annular spring receiver 214a at the equator of the valve body 214, a predetermined pressing force can always be maintained. In other words, if the normal-open compression spring 231 abuts against the spherical portion of the valve body 214, it will be compressed more when abutting against the central portion of the valve body 214 than when abutting against the peripheral portion due to variations in diameter of the normal-open compression spring 231. In contrast, in this example, since the normal-open compression spring 231 abuts against the annular portion, the length of the normal-open compression spring 231 in the installed state can be kept constant regardless of variations in diameter.

After energizing the solenoid valve 200 to switch the flow path, the pump 120 starts operating. High-pressure washer fluid from the pump 120 flows into the inlet passage 222, then flows out of the normally closed outlet passage 228 via the communication hole 226, the valve chamber 225, and the normally closed valve seat 229. The outflowing washer fluid is sprayed from the nozzle 100 through the normally closed piping 102a, the stop valve 101, and onto the rear window glass 130.

During this time, the force pushing the valve body 214 towards the normally open valve seat 227 is the compression force of the normally open compression spring 231. The excitation force Fs of the coil 205 only resists the compression force of the normally closed compression spring 207, and does not act to push up the valve body 214, because the plunger 209 and the valve body 214 are separate bodies. In order to reduce the size of the solenoid valve 200, it is necessary to make the compression force of the springs, including the normally open compression spring 231, and the excitation force of the coil 205 as small as possible.

The compression force of this spring is, for example, about 1.6 Newtons for the normally closed compression spring 207, and the excitation force Fs of the coil 205 is large enough that the sum of the compression force of the normally open compression spring 231 and the compression force of the normally closed compression spring 207 overcomes the compression force of the normally closed compression spring 207, for example, about 1.3 Newtons. The compression force of the normally open compression spring 231 is about 0.8 Newtons, half the compression force of the normally closed compression spring 207.

On the other hand, the washer fluid delivered from the pump 120 flows at a flow rate of about 2.5 liters per minute, which is quite fast in the valve chamber 225. For example, it may flow at a speed of about 9.5 meters per second. Furthermore, when passing through the normally closed valve seat 229, the washer fluid passes through the gap between the normally closed valve seat 229 and the valve body 214, so the flow rate of the washer fluid becomes even faster. As a result, the washer fluid pressure directly below the valve body 214 decreases. This decrease in washer fluid pressure acts in the direction that causes the normally closed valve seat 229 to close the valve body 214.

When the normally open valve seat 227 is closed, the normally open outflow passage 223 is at atmospheric pressure. Therefore, the washer fluid pressure PA in the valve chamber 225 basically acts in a direction to close the normally open valve seat 227. However, because the spring force of the normally open compression spring 231 is weak, the washer fluid pressure drops directly below the valve body 214, and the flow of washer fluid flowing into the valve chamber 225 from the communication hole 226 acts on the valve body 214 in a direction to open the normally open valve seat 227 (in the direction to push the valve body 214 down in FIG. 2), there is a possibility that the valve body 214 will move downward in FIG. 2 and open the normally open valve seat 227.

If the valve body 214 opens the normally open valve seat 227 even slightly, the pressure balance between the valve chamber 225 and the normally open outflow passage 223 is lost, which acts in the direction of opening the normally open valve seat 227 even more. As a result, the washer fluid flows into the normally open outflow passage 223. This causes the washer fluid to be sprayed unintentionally onto the camera 131.

In the present disclosure, in order to prevent such unintended opening of the normally open valve seat 227, a pressure chamber 240 is formed downstream of the valve body 214. The pressure chamber 240 obstructs the flow of washer fluid by the flow path restrictor 241, so that the pressure drop directly below the valve body 214 can be reduced. In this example, for example, the diameter of the flow path restrictor 241 is determined so that the pressure in the pressure chamber 240 is about three times higher than when the flow path restrictor 241 is not provided. Therefore, the pressure PB of the pressure chamber 240 relative to the pressure in the valve chamber 225 can be maintained within a certain differential pressure. As a result, the compression force of the normally open compression spring 231 only needs to exceed this differential pressure (PA-PB), and there is no need to make it larger than necessary. In this example, the differential pressure (PA-PB) is set to about 50 kilopascals, so the compression force of the normally open compression spring 231 is higher.

If the compression force of the normally open compression spring 231 can be set small, the compression force of the normally closed compression spring 207 that presses the valve body 214 against the normally closed valve seat 229 against the normally open compression spring 231 can also be set small. If the compression force of the normally closed compression spring 207 is small, the excitation force that moves the plunger 209 against the compression force of the normally closed compression spring 207 can also be weak. As a result, the number of turns of the coil 205 can be reduced, and the thickness of components such as the coil bobbin 204, yoke 201, and stator 211 can be reduced. These effects allow the solenoid valve 200 to be made smaller.

In particular, the solenoid valve 200 may be placed in an extremely narrow space, such as inside the back door of an automobile, and in such cases, it is required to minimize the size of the solenoid valve 200. This disclosure can meet this need for miniaturization.

When the valve body 214 is pressed against the normally open valve seat 227, as described above, the spherical portion of the valve body 214 abuts against the tapered shape of the normally open valve seat 227, so it is guided in a direction in which the axes are aligned. As a result, the valve body 214 abuts securely against the normally open valve seat 227, providing sufficient sealing performance.

When the cleaning of the rear window glass 130 is completed, the pump 120 is stopped, and when the pressure in the normally closed pipe 102a falls below the release pressure of the stop valve 101, the stop valve 101 also closes. At the same time, the power supply to the solenoid valve 200 is also stopped. Because a washer made of a non-magnetic material is interposed between the core 206 and the plunger 209, the plunger 209 is pushed down by the normally closed compression spring 207 when the power supply is stopped.

Because the biasing force of the normally closed compression spring 207 is greater than the biasing force of the normally open compression spring 231, the valve body 214 is pressed against the normally closed valve seat 229. The normally closed valve seat 229 also has a tapered shape that corresponds to the spherical shape of the valve body 214, so as described above, a reliable seal can be achieved.

In this way, according to the present disclosure, the valve body 214 is detachably abutted against the plunger 209, and the valve body 214 is spherical and arranged to fit within the tapered shapes of the normally open valve seat 227 and the normally closed valve seat 229, so there is no need to provide a guide for the valve body 214, and the assembly of the valve body 214 is easy. In other words, even if the axis of the valve body 214 is slightly shifted due to the influence of the normally open compression spring 231 or the flow of washer fluid, the shift of the valve body 214 is within the range of the normally open valve seat 227 and the normally closed valve seat 229, so it is pressed against the normally open valve seat 227 or the normally closed valve seat 229 by the normally closed compression spring 207 or the washer fluid pressure. And since both the normally open valve seat 227 and the normally closed valve seat 229 are tapered, the valve body 214 is guided by the tapered shape and abuts against the normally open valve seat 227 or the normally closed valve seat 229 around its entire circumference.

When the ambient temperature rises while the pump 120 is not operating, the washer fluid and air in the pipe 102 expand. Even though the normally open pipe 102b is closed by the stop valve 101, the normally open valve seat 227 is open, so the pressure is released to the pump 120 side and does not increase. However, in the normally closed pipe 102a, both the normally closed valve seat 229 and the stop valve 101 are closed, so the washer fluid is trapped in the normally closed pipe 102a. As a result, there is a risk that the pressure in the normally closed pipe 102a will increase due to the expansion of the washer fluid and air.

If the pressure exceeds the release pressure of the stop valve 101, the washer fluid in the normally closed pipe 102a may drip from the nozzle 100 onto the rear window glass 130. However, in this disclosure, the pressure relief valve 233 opens to release the pressure, so leakage of the washer fluid can be reliably prevented.

When the pressure in the normally closed pipe 102a becomes higher than the relief pressure, it overcomes the biasing force of the pressure relief spring 216 and lifts the pressure relief valve body 217. As a result, the pressure relief valve seat 218 opens and the pressure relief passage 232 is opened. The normally closed outflow passage 228 communicates with the inflow passage 222 via the pressure relief groove 217a of the pressure relief valve body 217 and the pressure relief guide 234.

The relief pressure of the pressure relief valve 233 is approximately half the release pressure of the stop valve 101, so the pressure relief valve 233 opens before the stop valve 101 opens, preventing a pressure rise in the normally closed piping 102a.

Here, the pressure relief passage 232 releases the pressure of trapped washer fluid, so a large amount of washer fluid does not flow through the pressure relief passage 232. Therefore, even if there is a part with a small flow path cross-sectional area such as the pressure relief groove 217a, it does not cause a malfunction. In Figure 6, three pressure relief grooves 217a are formed, but this is to balance the shape by creating a symmetrical shape around the axis, and the number of pressure relief grooves 217a is sufficient in terms of the flow path cross-sectional area.

In addition, since the pressure relief valve body 217 is held by the guide 234, a seal between the pressure relief valve body 217 and the pressure relief valve seat 218 is ensured even if the set pressure of the pressure relief spring 216 is small.

Second Embodiment
In the above-described embodiment, the three-way valve includes a normally closed outflow passage 228 (outflow passage) and a normally open outflow passage 223 (second outflow passage) as outflow passages, but the third embodiment is an on-off two-way valve whose only outflow passage is the normally closed outflow passage 228. Fig. 7 shows the second embodiment, and the structure of the solenoid valve 200 is the same as that of the first embodiment, except that the normally open outflow passage 223 is omitted.

Two-way valves are effective when there are multiple normally closed pipes 102a. In this case, there are multiple sensors that need to be cleaned with washer fluid. When the coil 205 is not excited, the two-way valve also closes the valve seat (normally closed valve seat 229) with the compression force of the normally closed compression spring 207.

Figure 7 shows the excited state of the coil 205, and just like the first embodiment, the washer fluid that passes through the normally closed valve seat 229 recovers pressure in the pressure chamber 240. In other words, the flow of washer fluid is obstructed by the flow path restriction section 241, and no more pressure drop than necessary occurs. Therefore, just like the first embodiment, it is possible to achieve a smaller solenoid valve 200.

Third Embodiment
In the first embodiment, the flow passage restricting portion 241 that defines the pressure chamber 240 is integrally formed with the lower body 219. This has the advantage of not increasing the number of parts, but on the other hand, it has the disadvantage of making the mold for forming the flow passage restricting portion 241 complicated.

In the third embodiment, as shown in Figures 8 to 10, the flow path restrictor 243 is formed as a separate member and is incorporated into the lower body 219. The flow of washer fluid is obstructed by passing through the flow path restrictor hole 242 of the flow path restrictor 243, and the pressure drop in the pressure chamber 240 is restored. The pressure chamber 240 is formed upstream of the flow path restrictor portion 241 of the flow path restrictor 243. Note that the part of the flow path restrictor 243 downstream of the flow path restrictor hole 242 becomes the normally closed outflow passage 228.

Fourth Embodiment
In the above embodiment, the pressure of the washer fluid in the pressure chamber 240 is restored by the flow path throttle portion 241, but other means may be used as long as they can prevent a significant reduction in pressure by impeding the flow of the washer fluid. For example, a filter that is not clogged by foreign matter may be disposed in the normally closed outflow passage 228 to partition the pressure chamber 240. As shown in FIG. 12, a filter structure in which the flow path throttle member 243 is a separate member and multiple filter holes 242a are formed in the flow path throttle portion 241 may be used. In addition, the pressure chamber 240 can be formed even if the normally closed outflow passage 228 is bent downstream of the normally closed valve seat 229 to impede the flow of the washer fluid.

Other Embodiments
In the above embodiment, the upper body 212 and the lower body 219 are welded together, but other fixing methods such as bolt fixing, clip fixing, etc. may also be used. In addition, although it is effective to use flanges 212a and 219a to join the upper body 212 and the lower body 219, they can be joined together without the flanges.

In the above embodiment, the inlet passage 222 and the normally open outlet passage 223 are arranged in a straight line, but they may be perpendicular to each other or may intersect at another angle. The same applies to the relationship between the inlet passage 222 and the normally closed outlet passage 228. They may also be arranged in parallel, not perpendicular to each other, or may intersect at another angle.

In the above embodiment, the valve body 214 is spherical, but as shown in FIG. 11, the upper surface 214b that contacts the normally open valve seat 227 and the lower surface 214c that contacts the normally closed valve seat 229 may both be hemispherical with a cylindrical portion 214d between them. In an embodiment in which the cylindrical portion 214d is formed between them, a spring support 214a may be formed on the cylindrical portion.

It is preferable that the shape of the valve body 214 be spherical, but it is not necessarily limited to a shape having a spherical surface. It may be a tapered surface, or it may be a flat surface. In addition, the shapes of the normally closed valve seat 229 and the normally open valve seat 227 are not limited to being tapered, and may be an arc shape capable of guiding the valve body 214.

In addition, although washer fluid is used as the working fluid, other liquids such as water or oil may also be used as the working particles.

The disclosure in this specification and the drawings is not limited to the illustrated embodiments. The disclosure encompasses the illustrated embodiments and variations thereon by those skilled in the art.

205... coil 206... core 207... normally closed compression spring 209... plunger 214... valve body 222... inlet passage 223... normally open outlet passage 225... valve chamber 227... normally open valve seat 228... normally closed outlet passage 229... normally closed valve seat 231... normally open compression spring 240... pressure chamber 241... flow path restriction section

Claims (7)

A coil that is excited when current is applied;
a core made of a magnetic material that is disposed in a magnetic circuit when the coil is energized;
a plunger disposed in a magnetic circuit facing the core with a magnetic gap therebetween when the coil is energized;
a valve body that comes into contact with the plunger and moves together with the plunger;
a valve body having an inlet passage for a working fluid, an outlet passage for the working fluid, a valve seat formed between the inlet passage and the outlet passage and against which the valve element abuts, a valve chamber formed between the valve seat and the inlet passage, and a pressure chamber formed between the valve seat and the outlet passage;
a normally-closed compression spring that abuts against the plunger and presses the plunger in a direction away from the core and in a direction toward the valve body and toward the valve seat;
a normally open compression spring that abuts against the valve body and presses the valve body in a direction away from the valve seat,
the pressure chamber is formed directly below the valve body by a flow passage narrowing portion disposed in the outflow passage,
a flow path restrictor in the pressure chamber that restricts the flow of the working fluid from the valve body to the pressure chamber, thereby restoring the pressure of the working fluid to the pressure chamber and reducing a pressure drop immediately below the valve body . 2. The solenoid valve according to claim 1 , wherein the flow passage restriction portion is integrally formed with the valve body. 2. The solenoid valve according to claim 1 , wherein the flow passage throttle portion is formed in a flow passage throttle member, and the flow passage throttle member is disposed in the valve body to define the pressure chamber within the valve body. A coil that is excited when current is applied;
a core made of a magnetic material that is disposed in a magnetic circuit when the coil is energized;
a plunger disposed in a magnetic circuit facing the core with a magnetic gap therebetween when the coil is energized;
a valve body that comes into contact with the plunger and moves together with the plunger;
a valve body having an inlet passage for a working fluid, an outlet passage for the working fluid, a valve seat formed between the inlet passage and the outlet passage and against which the valve element abuts, a valve chamber formed between the valve seat and the inlet passage, and a pressure chamber formed between the valve seat and the outlet passage;
a normally-closed compression spring that abuts against the plunger and presses the plunger in a direction away from the core and in a direction toward the valve body and toward the valve seat;
a normally open compression spring that abuts against the valve body and presses the valve body in a direction away from the valve seat,
When the valve body is separated from the valve seat, the working fluid that flows from the valve chamber into the pressure chamber is impeded in the pressure chamber, and the pressure of the working fluid is restored.
The valve body is spherical and has an annular spring bearing formed at its equator.
The plunger abuts on a central axis of the valve body,
The normally open compression spring abuts against the spring bearing of the valve body. the valve body includes a second outflow passage communicating with the valve chamber, and a second valve seat formed between the second outflow passage and the valve chamber,
5. The solenoid valve according to claim 1, wherein the second valve seat faces the valve seat, and when the valve body is in contact with the valve seat, the valve body is separated from the second valve seat, and when the valve body is separated from the valve seat, the valve body is in contact with the second valve seat . the valve seat is a normally closed valve seat with which the valve body comes into contact when the coil is not excited,
The solenoid valve according to claim 5 , wherein the second valve seat is a normally open valve seat from which the valve body is separated when the coil is de-energized. The valve body is spherical,
The normally closed valve seat and the normally open valve seat are disposed opposite each other,
The solenoid valve according to claim 6 , wherein both of the first and second portions have an arc shape corresponding to the spherical shape of the valve body.

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