Solenoids, solenoid valves and buffers

Abstract

The solenoid (S1) of the present invention comprises: a first fixed iron core (5) and a second fixed iron core (6), wherein the first fixed iron core (5) and the second fixed iron core (6) are located at one end side and the other end side of the coil (4) in the axial direction; a first movable part (7) and a second movable part (8), wherein the first movable part (7) and the second movable part (8) are located between the first fixed iron core (5) and the second fixed iron core (6) and are attracted by the first fixed iron core (5) and the second fixed iron core (6) respectively when power is supplied to the coil (4); a spring (9), wherein the spring (9) applies a force to the first movable part (7) toward the second fixed iron core (6); and a first limiting part (90), wherein the first limiting part (90) is integrally provided with the first movable part (7) or the second movable part (8) and is composed of a non-magnetic body to limit the movement of the first movable part (7) toward the second fixed iron core (6) relative to the second movable part (8).

Description

Technical Field

[0001] The present invention relates to a solenoid, a solenoid valve including the solenoid, and a shock absorber including the solenoid valve. Background Art

[0002] Conventional solenoids typically consist of a coil and a movable element that, when current is applied to the coil and a magnetic field is generated, magnetic flux flows, attracting the movable element in one direction of the coil's axis. This solenoid can impart the force of attraction to the movable element as thrust to another component (object), varying this thrust depending on the amount of current applied. This type of solenoid is used, for example, in solenoid valves.

[0003] One type of solenoid valve is located midway in a pressure control channel. In addition to a solenoid, it also includes a valve body for opening and closing the pressure control channel, and a spring biasing the valve body in the opening direction. The solenoid applies a closing force to the valve body. With this type of solenoid valve, the greater the current supplied to the solenoid, the higher the valve opening pressure, increasing the pressure upstream of the valve. This type of solenoid valve is used, for example, in shock absorbers.

[0004] Furthermore, one type of shock absorber of this type includes, in addition to a solenoid valve, a main channel through which fluid flows when the shock absorber expands and contracts, and a main valve body for opening and closing the main channel. This main valve body connects a pressure control channel containing the solenoid valve to a backpressure chamber formed on the back side of the main valve body. With this type of shock absorber, as the current supplied to the solenoid increases and the solenoid valve-opening pressure increases, the backpressure in the main valve body (the pressure in the backpressure chamber) increases, resulting in a greater damping force (e.g., Patent Document 1).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-173716 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] When shock absorbers are used in vehicle suspensions, it is desirable to maintain good ride comfort during normal driving on clear roads while reducing the damping force generated during normal driving. Furthermore, in shock absorbers equipped with a solenoid valve containing a conventional solenoid, reducing the current supplied to the solenoid can reduce the generated damping force, thereby suppressing power consumption during normal driving and saving electricity. However, in conventional shock absorbers, if the solenoid fails, the solenoid valve fully opens, minimizing the back pressure in the main valve body, and the damping force during the fault condition becomes insufficient.

[0010] Therefore, the solenoid valve body of the shock absorber disclosed in Japanese Patent Application Laid-Open No. 2014-173716 has two opening and closing sections that open and close the pressure control channel. One of the opening and closing sections is biased in the opening direction by a spring and functions as the opening and closing section during pressure control, when the solenoid applies a closing thrust. Meanwhile, when the solenoid is de-energized, the other opening and closing section, when one of the opening and closing sections is fully open due to the spring force, closes the downstream side of the portion of the pressure control channel opened and closed by the other opening and closing section.

[0011] Furthermore, the shock absorber features a fail-safe passage connected between the portion of the pressure control channel opened and closed by one opening and closing unit and the portion opened and closed by the other opening and closing unit, with a passive valve interposed in between. Consequently, when the solenoid is de-energized and the pressure control channel is closed by the other opening and closing unit of the solenoid valve, the fluid in the backpressure chamber flows through the fail-safe passage, and the backpressure of the main valve body is set to the valve-opening pressure of the passive valve. Consequently, even with conventional shock absorbers, the damping force is not insufficient in the event of a failure.

[0012] However, as shown in the aforementioned damper, two channels—a pressure control channel and a fail-safe channel—are provided as the channels connected to the backpressure chamber to set the backpressure of the main valve body. Switching the channel connected to the backpressure chamber between when the solenoid is energized and when it is de-energized complicates the damper's structure and incurs considerable cost. Furthermore, while switching the channel connected to the backpressure chamber between when the solenoid is energized and when it is de-energized is unnecessary, reducing the generated damping force requires increasing the current supplied to the solenoid, which increases power consumption during normal driving.

[0013] Specifically, when using a solenoid in a variable damping force solenoid valve, for example, a shock absorber, it is desirable to reduce the thrust applied to an object such as a valve body when the current supplied to the solenoid is low. Furthermore, it is desirable to apply a force in the same direction as the thrust even when the solenoid is not energized. This is not possible with conventional solenoids. Consequently, using conventional solenoids in shock absorber variable damping force solenoid valves results in a complex shock absorber structure and increased power consumption during normal vehicle operation.

[0014] The present invention was developed to address this problem, and its purpose is to provide a solenoid, solenoid valve, and shock absorber that can reduce the thrust exerted by the solenoid on an object when the current supplied to the solenoid is low, and that can also exert force on the object in the same direction as the thrust when energized, even when the solenoid is not energized.

[0015] Solutions to Problems

[0016] The solenoid for solving the above-mentioned problem comprises: a first fixed iron core and a second fixed iron core, wherein the first fixed iron core and the second fixed iron core are located at one end side and the other end side of the coil axial direction; a first movable part and a second movable part, wherein the first movable part and the second movable part are located between the first fixed iron core and the second fixed iron core and are attracted by the first fixed iron core and the second fixed iron core respectively by energizing the coil; a spring, wherein the spring applies force to the first movable part toward the second fixed iron core; a first limiting part, wherein the first limiting part is integrated with the first movable part or the second movable part and is composed of a non-magnetic body to limit the movement of the first movable part toward the second fixed iron core relative to the second movable part.

[0017] According to the above structure, when the solenoid is de-energized, the first movable member is advanced toward the second fixed core by the spring force. If the first movable member's movement toward the second fixed core relative to the second movable member is restricted by the first restricting portion, the spring force is transmitted from the first movable member to the second movable member. On the other hand, when the solenoid is energized, if the first movable member is attracted by the first fixed core and moves in the direction of attraction, the spring is compressed by the first movable member, and the spring force is not transmitted to the second movable member. Furthermore, when the solenoid is energized, the second movable member is attracted to the second fixed core, and the force pulling the second movable member toward the second fixed core increases as the current supplied to the solenoid increases.

[0018] Therefore, when the solenoid is energized, the force that attracts the second movable member is applied as thrust to the object. The greater the current supplied to the solenoid, the greater the thrust applied to the object, while the smaller the current supplied to the solenoid, the smaller the thrust applied to the object. Furthermore, when the solenoid is not energized, the spring force acts on the object via the first and second movable members. The direction of the spring force is the same as the direction of the force that attracts the second movable member when the solenoid is energized. Therefore, with this structure, even when the solenoid is not energized, the object can still be thrust in the same direction as when energized.

[0019] Furthermore, according to the above configuration, the first restricting portion is formed of a non-magnetic material, thereby preventing the first and second movable members from being attracted to each other when the coil is energized. Furthermore, since the first restricting portion is integrally provided with the first or second movable member, it is possible to prevent the first and second movable members from vibrating when a PWM control current is applied to the solenoid, for example, thereby preventing the first restricting portion from being excited to vibrate and thereby amplifying high-frequency sound.

[0020] Furthermore, the solenoid may also include a second limiting portion, integrally formed with the second movable member or the second fixed core and constructed from a non-magnetic material, to limit the second movable member's movement toward the second fixed core. This non-magnetic nature of the second limiting portion prevents the second movable member from being attracted to the second fixed core when the coil is energized. Furthermore, the integration of the second limiting portion with the second movable member or the second fixed core prevents the second movable member from vibrating when a PWM control current is applied to the solenoid, thereby preventing the second limiting portion from vibrating due to the current, which could in turn cause the second movable member to vibrate, thereby increasing high-frequency sound.

[0021] In addition, the above-mentioned solenoid can also be equipped with an annular filling ring, which is installed between the first fixed iron core and the second fixed iron core, and the second movable component is in the shape of a bottomed cylinder, having an outer bottom and an outer cylinder portion, and the outer bottom is inserted into the inner side of the filling ring in an axially movable manner toward the second fixed iron core side, and the first movable component is in the shape of a bottomed cylinder, having an inner bottom and an inner cylinder portion, and the inner bottom is directed toward the second fixed iron core side, and the inner cylinder portion is inserted into the inner side of the outer cylinder portion in an axially movable manner, and the spring is installed between the inner bottom and the first fixed iron core in a manner that one end side is inserted into the inner side of the inner cylinder portion.

[0022] According to the above structure, by making the inner cylindrical portion of the first movable member and the outer cylindrical portion of the second movable member magnetic, when the coil is excited, a magnetic circuit passes through the first fixed core, the first movable member, the second movable member, and the second fixed core, thereby attracting the first movable member toward the first fixed core and the second movable member toward the second fixed core. Furthermore, while ensuring sufficient space for accommodating the spring inside the first movable member, the solenoid can be miniaturized.

[0023] Furthermore, according to the above structure, when the first movable member moves toward the second fixed core, the inner bottom of the first movable member approaches the outer bottom of the second movable member. Furthermore, when the second movable member moves toward the second fixed core, the outer bottom of the second movable member approaches the second fixed core. Therefore, if the first and second restricting portions are configured to restrict their movement in the approaching direction, each restricting portion can be used to restrict movement of the first movable member relative to the second movable member toward the second fixed core, or to restrict movement of the second movable member toward the second fixed core, making it easy to configure the first and second restricting portions.

[0024] In addition, the above-mentioned solenoid can also be provided with an annular filling ring, which is installed between the first fixed iron core and the second fixed iron core, and the first movable component has: an inner cylinder portion and an outer cylinder portion arranged in two layers inside and outside; a connecting portion connecting the inner cylinder portion and one axial end of the outer cylinder portion; and an inner bottom portion located at the other end of the inner cylinder portion, the inner bottom portion is inserted into the inner side of the filling ring in a slidable manner toward the second fixed iron core side, the second movable component is in the shape of a bottomed cylinder, has an outer bottom portion, and an intermediate cylinder portion with an inner diameter larger than the outer diameter of the inner cylinder portion, the outer bottom portion is directed toward the second fixed iron core side, the intermediate cylinder portion is inserted into the inner side of the outer cylinder portion in a slidable manner, and the spring is installed between the inner bottom portion and the first fixed iron core in a manner with one end side inserted into the inner side of the inner cylinder portion.

[0025] According to the above structure, by making the outer cylindrical portion of the first movable member and the intermediate cylindrical portion of the second movable member magnetic, when the coil is excited, a magnetic circuit passes through the first fixed core, the first movable member, the second movable member, and the second fixed core, thereby attracting the first movable member toward the first fixed core and the second movable member toward the second fixed core. Furthermore, space for accommodating the spring can be ensured inside the first movable member.

[0026] Furthermore, according to the above structure, when the first movable member moves toward the second fixed core, the inner bottom of the first movable member approaches the outer bottom of the second movable member. Furthermore, when the second movable member moves toward the second fixed core, the outer bottom of the second movable member approaches the second fixed core. Therefore, if the first and second restricting portions are configured to restrict their movement in the approaching direction, each restricting portion can be used to restrict movement of the first movable member relative to the second movable member toward the second fixed core, or to restrict movement of the second movable member toward the second fixed core, making it easy to configure the first and second restricting portions.

[0027] Alternatively, the solenoid may include a limiting member mounted on the outer bottom portion, the limiting member comprising: an insertion shaft, one end of which is press-fitted into a through-hole formed in the outer bottom portion so as to protrude from the outer bottom portion toward the second fixed core; and a seat portion extending outwardly from the other end of the insertion shaft and positioned between the outer bottom portion and the inner bottom portion, the seat portion functioning as a first limiting member, and the end of the insertion shaft protruding from the outer bottom portion toward the second fixed core portion functioning as a second limiting member. This facilitates integrating both the first and second limiting members with the second movable member.

[0028] Furthermore, the solenoid may include a limiting member mounted on the outer bottom portion, the limiting member comprising: an insertion shaft, one end of which is press-fitted into a through-hole formed in the outer bottom portion so as to protrude from the outer bottom portion toward the first fixed core; and a seat portion extending outwardly from the other end of the insertion shaft and positioned between the outer bottom portion and the second fixed core portion, the one end of the insertion shaft protruding from the outer bottom portion toward the first fixed core portion functioning as the first limiting member, and the seat portion functioning as the second limiting member. Even in this manner, it is easy to integrate both the first and second limiting members with the second movable member.

[0029] Alternatively, in the solenoid described above, in which the second movable member has an outer cylindrical portion, the first limiting portion may be an annular member pressed into the inner circumference of the outer cylindrical portion. In this case, it is easy to separate the first limiting portion from the second limiting portion and integrate them with the second movable member. Furthermore, a portion of the first movable member, such as the inner bottom portion of the first movable member or a portion including the inner bottom portion and the inner cylindrical portion, may be formed of a non-magnetic material and function as the first limiting portion. In this case, it is also easy to integrate the first limiting portion with the first movable member.

[0030] In addition, the second fixed core of the solenoid may have an annular protrusion, the inner side of which is for the end of the second fixed core side of the second movable part to be inserted, and the second limiting part may be an annular member and be pressed into the inner periphery of the annular protrusion. In this case, it is easy to integrate the second limiting part and the second fixed core. Furthermore, it is also possible that the second limiting part has: a seat portion, which is located between the outer bottom of the second movable part and the second fixed core; and a fitting portion, which protrudes from the seat portion and is pressed into a through hole formed in the outer bottom. In this case, it is easy to integrate the second limiting part and the second movable part separately from the first limiting part.

[0031] Alternatively, the solenoid can be installed in a solenoid valve disposed midway in the pressure control passage. This solenoid valve includes, in addition to the solenoid, a valve body for opening and closing the pressure control passage. When the solenoid coil is energized, the solenoid exerts a force on the valve body, which attracts the second movable member toward the second fixed core, in the direction of closing the pressure control passage. In this manner, the solenoid valve's valve-opening pressure can be adjusted by varying the current supplied to the solenoid, with the pressure upstream of the solenoid valve being set as the valve-opening pressure.

[0032] Furthermore, as described above, the greater the current supplied to the solenoid, the greater the thrust applied to the object. Therefore, in the solenoid valve, the greater the current supplied to the solenoid, the greater the thrust applied to the valve body in the closing direction, thereby increasing the valve opening pressure of the solenoid valve. Furthermore, as described above, the solenoid still exerts a force on the object in the same direction as the thrust applied when energized, even when de-energized. Therefore, the de-energized valve opening pressure of the solenoid valve can be determined based on the spring specifications.

[0033] In addition, the solenoid valve including the above-mentioned solenoid can also be set in a buffer, which comprises: a cylinder; a rod, which is inserted into the cylinder in an axially movable manner; a main channel, which allows liquid to flow through when the cylinder and the rod move axially relative to each other; a main valve body, which is used to open and close the main channel; a pressure inlet channel, which is provided with a throttle in the middle of the pressure inlet channel, and reduces the pressure on the upstream side of the main valve body of the main channel and guides it to the back side of the main valve body; and a pressure control channel, which is connected to the downstream of the throttle of the pressure inlet channel and is provided with the above-mentioned solenoid valve.

[0034] In this way, when the cylinder and rod move axially relative to each other, the main valve body imparts resistance to the flow of fluid through the main passage, and the shock absorber generates a damping force due to this resistance. Furthermore, since the back pressure of the main valve body is set to the solenoid valve opening pressure, the back pressure can be adjusted by varying the current supplied to the solenoid. Furthermore, the higher the back pressure on the main valve body, the harder it is to open the main valve body, and the greater the damping force generated. Therefore, with this structure, the magnitude of the damping force generated can be adjusted by varying the current supplied to the solenoid.

[0035] Furthermore, as described above, in the solenoid valve, the higher the current supplied to the solenoid, the higher the valve opening pressure of the solenoid. Therefore, in the damper, the higher the current supplied to the solenoid, the higher the back pressure on the main valve body, and the greater the damping force generated. Specifically, since the damper generates less damping force when the current supplied to the solenoid is lower, power consumption during normal driving can be reduced when the damper is used in a vehicle suspension. Furthermore, this suppresses solenoid heat generation, minimizing temperature fluctuations in the damper, thereby reducing changes in damping force characteristics (damping force characteristics relative to piston velocity) caused by changes in fluid temperature.

[0036] Furthermore, as described above, in the solenoid valve, the valve opening pressure when de-energized is determined by the spring specifications. Therefore, the damper can increase the back pressure of the main valve body even when the solenoid is de-energized. This prevents the damper from experiencing insufficient damping force during a malfunction. Furthermore, in the damper, a pressure control channel is sufficient as the channel for setting the back pressure of the main valve body. This eliminates the need to switch the channel for setting the back pressure when the solenoid is energized and when it is de-energized. This reduces the complexity of the damper structure and reduces costs.

[0037] Effects of the Invention

[0038] According to the solenoid, electromagnetic valve, and buffer of the present invention, the thrust applied by the solenoid to the object can be reduced when the current supplied to the solenoid is small, and when the solenoid is not energized, the object can still be thrusted in the same direction as when energized. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a longitudinal sectional view of a shock absorber including a solenoid valve including the solenoid according to the first embodiment of the present invention.

[0040] Figure 2 It is an enlarged longitudinal sectional view showing a solenoid valve including a solenoid according to the first embodiment of the present invention.

[0041] Figure 3 It is a partially enlarged cross-sectional view of the solenoid according to the first embodiment of the present invention.

[0042] Figure 4 This is a characteristic diagram showing the relationship between the amount of supplied current and the force acting in the direction of pressing down the valve body in the solenoid according to the first embodiment of the present invention.

[0043] Figure 5 FIG. 1 shows a first modified example of the solenoid according to the first embodiment of the present invention, and is a partially enlarged cross-sectional view of the solenoid according to the modified example.

[0044] Figure 6 FIG. 1 shows a second modified example of the solenoid according to the first embodiment of the present invention, and is a partially enlarged cross-sectional view of the solenoid according to the modified example.

[0045] Figure 7 FIG. 1 shows a third modified example of the solenoid according to the first embodiment of the present invention, and is a partially enlarged cross-sectional view of the solenoid according to this modified example.

[0046] Figure 8 (a) is a partially enlarged cross-sectional view of a solenoid according to a second embodiment of the present invention. Figure 8 (b) Yes Figure 8 (a) Enlarged view of part X. DETAILED DESCRIPTION

[0047] The embodiments of the present invention will be described below with reference to the accompanying drawings. In the multiple drawings, the same symbols are used to represent the same components (parts) or corresponding components (parts).

[0048] In each embodiment, a solenoid is used in a solenoid valve, the solenoid valve is used in a shock absorber, and the shock absorber is used in a vehicle suspension. However, the purpose of use of the solenoid, the solenoid valve including the solenoid, and the shock absorber including the solenoid valve according to the present invention is not limited to the above and can be modified as appropriate.

[0049] <First embodiment>

[0050] like Figure 1 As shown, a shock absorber D equipped with a solenoid valve V including a solenoid according to the first embodiment of the present invention comprises: a cylinder 1; a piston 10 slidably inserted into the cylinder 1; and a piston rod 11, one end of which is connected to the piston 10 and the other end of which protrudes out of the cylinder 1. Furthermore, one of the vehicle body and the axle is connected to the cylinder 1, and the other is connected to the piston rod 11. Thus, the shock absorber D is installed between the vehicle body and the axle.

[0051] Moreover, if the vehicle is running on an uneven road, the wheels vibrate up and down, the piston rod 11 moves in and out of the cylinder 1, the buffer D expands and contracts, and the piston 10 moves in the cylinder 1 along the Figure 1 In addition, Figure 1 Although the piston rod 11 is shown in a state protruding upward from the cylinder 1 , the shock absorber D may be mounted on the vehicle in any orientation.

[0052] An annular head member 12 is attached to one axial end of the cylinder 1. The inner side of this annular head member 12 allows the piston rod 11 to pass through. This head member 12 supports the piston rod 11 in a slidable manner and seals one end of the cylinder 1. Meanwhile, the other end of the cylinder 1 is sealed by a bottom cap 13. This seals the interior of the cylinder 1, trapping liquid and gas within it.

[0053] More specifically, a free piston 14 is inserted into the cylinder 1 so as to slide freely on the side opposite to the piston rod 11 when viewed from the piston 10. Furthermore, a liquid chamber L for filling with a liquid such as hydraulic oil is formed on the piston 10 side of the free piston 14 within the cylinder 1. Meanwhile, a gas chamber G for enclosing compressed gas is formed on the side opposite to the piston 10 when viewed from the free piston 14 within the cylinder 1.

[0054] Thus, the liquid chamber L and the gas chamber G in the cylinder 1 are separated by the free piston 14. Furthermore, if the piston rod 11 moves in and out of the cylinder 1 when the buffer D is extended or retracted, the free piston 14 moves in the cylinder 1 along the Figure 1 The up and down (axial) movement expands or contracts the gas chamber G to compensate for the volume of the piston rod 11 entering and exiting the cylinder 1.

[0055] In addition, in addition to being separated by the free piston 14, the liquid chamber L and the gas chamber G can also be separated by an air bag or a bellows. That is, the structure of the movable partition forming the expandable and contractible gas chamber G is not limited to the free piston 14, and can be appropriately changed. Furthermore, the structure for compensating for the volume of the piston rod 11 entering and exiting the cylinder 1 is not limited to the gas chamber G, and can be appropriately changed. For example, a liquid reservoir for containing liquid and gas can be provided to replace the gas chamber G, and the liquid is exchanged between the cylinder and the liquid reservoir when the buffer is extended and retracted. In addition, the buffer D can also adopt a double-rod type, with piston rods provided on both sides of the piston. In this case, the structure itself for compensating for the volume of the piston rod can be omitted.

[0056] Then, the liquid chamber L inside the cylinder 1 is divided by the piston 10 into an expansion side chamber L1 on the piston rod 11 side and a compression side chamber L2 on the opposite side (the side opposite to the piston rod). Figure 2 As shown, the piston 10 is in the shape of a bottomed cylinder, which comprises: a cylinder portion 10b, the outer periphery of which is provided with a piston ring 10a that is in sliding contact with the inner periphery of the cylinder 1; and a bottom portion 10c, which closes one end of the cylinder portion 10b. Figure 2 The up and down directions are referred to as “up” and “down” for short.

[0057] In this manner, piston 10 is positioned with its bottom portion 10c facing downward and its cylindrical portion 10b facing upward. This cylindrical portion 10b is connected to the topped cylindrical outer portion 11a formed at the front end of piston rod 11 via a cylindrical guide 15. An annular valve seat member 16 is fixed between the lower end of this guide 15 and piston 10. Furthermore, the main valve body 2 is mounted on the valve seat member 16 inside the guide 15 so as to be movable up and down.

[0058] The main valve body 2 has a first valve body portion 2A and a second valve body portion 2B that can be separated vertically. An intermediate chamber L3 is formed between the main valve body 2 and the bottom 10c of the piston 10. The intermediate chamber L3 is separated from the compression-side chamber L2 by the piston 10. Furthermore, the bottom 10c of the piston 10 has expansion-side and compression-side ports 10d and 10e formed therein, connecting the intermediate chamber L3 with the compression-side chamber L2. Furthermore, an expansion-side valve 20 is stacked on the lower side of the bottom 10c, which opens and closes the outlet of the expansion-side port 10d. A compression-side valve 21 is stacked on the upper side of the bottom 10c, which opens and closes the outlet of the compression-side port 10e.

[0059] The inlet of the expansion-side port 10d opens into the intermediate chamber L3, and the pressure of the intermediate chamber L3 acts in a direction that opens the expansion-side valve 20. When the expansion-side valve 20 opens due to the pressure of the intermediate chamber L3, the liquid in the intermediate chamber L3 flows into the compression-side chamber L2 through the expansion-side port 10d. Meanwhile, the inlet of the compression-side port 10e opens into the compression-side chamber L2, and the pressure of the compression-side chamber L2 acts in a direction that opens the compression-side valve 21. When the pressure of the compression-side chamber L2 opens the compression-side valve 21, the liquid in the compression-side chamber L2 flows into the intermediate chamber L3 through the compression-side port 10e.

[0060] Next, as described above, the main valve body 2 includes a first valve body portion 2A and a second valve body portion 2B that can be separated vertically. The first valve body portion 2A is annular, and its front end is inserted into the inner side of the valve seat member 16 in a manner that allows free axial movement and can be seated on the valve seat member 16. On the other hand, the second valve body portion 2B includes: a head portion 2a; and a flange portion 2b that extends outward from the lower end of the head portion 2a. Moreover, the head portion 2a and the flange portion 2b of the second valve body portion 2B are respectively in sliding contact with the inner periphery of the guide member 15, and the lower end of the second valve body portion 2B can be seated on the first valve body portion 2A.

[0061] Furthermore, the guide member 15 is formed with a through hole 15a that opens into the expansion-side chamber L1. The pressure in the expansion-side chamber L1 acts in a direction that pushes both the first valve body 2A and the second valve body 2B upward, causing the first valve body 2A to be removed from the valve seat member 16. Furthermore, when the first valve body 2A and the second valve body 2B move upward together under the pressure in the expansion-side chamber L1 and are removed from the valve seat member 16, the liquid in the expansion-side chamber L1 flows into the intermediate chamber L3 through the gap formed between the first valve body 2A and the valve seat member 16.

[0062] The intermediate chamber L3 is located within the valve seat member 16, the first valve body 2A, and the inner circumference of the piston 10's cylindrical portion 10b. It is formed between the piston 10's bottom portion 10c and the second valve body 2B. The pressure in the intermediate chamber L3 acts in a direction that pushes the first valve body 2A downward and in a direction that pushes the second valve body 2B upward. In other words, the pressure in the intermediate chamber L3 acts in a direction that separates the first and second valve bodies 2A, 2B, and causes the second valve body 2B to unseat from the first valve body 2A. Furthermore, when the pressure in the intermediate chamber L3 causes the second valve body 2B to move upward and unseat from the first valve body 2A, the liquid in the intermediate chamber L3 flows into the expansion-side chamber L1 through the gap formed between the first and second valve bodies 2A, 2B, and the through-hole 15a.

[0063] In summary, in this embodiment, a main passage M is formed by the through hole 15a of the guide member 15, the intermediate chamber L3, and the expansion-side and compression-side ports 10d and 10e, connecting the expansion-side chamber L1 and the compression-side chamber L2. Furthermore, the main valve body 2 is disposed in the main passage M, and an expansion-side valve 20 and a compression-side valve 21 are provided in series with the main valve body 2.

[0064] Next, a back-pressure chamber L4 is formed on the upper surface of the flange portion 2b, which serves as the back side of the main valve body 2. The pressure in this back-pressure chamber L4 acts in a direction that pushes the second valve body 2B downward along with the first valve body 2A. Furthermore, the second valve body 2B is formed with a pressure introduction passage p1, which has a throttle O midway through it and reduces the pressure in the expansion-side chamber L1 before directing it to the back-pressure chamber L4; a pressure control passage p2, which is connected to the pressure introduction passage p1 downstream of the throttle O; and a pressure reduction passage p3, which allows only liquid to flow from the intermediate chamber L3 to the back-pressure chamber L4 and reduces the pressure in the intermediate chamber L3 before directing it to the back-pressure chamber L4.

[0065] Furthermore, a solenoid valve V including a solenoid S1 according to this embodiment is disposed midway along the pressure control passage p2. This solenoid valve V comprises a valve element 3, which serves as a valve body and opens and closes the pressure control passage p2 by seating on a valve seat 22 provided in the second valve body portion 2B; and a solenoid S1, which applies a downward thrust to the valve element 3. When the valve element 3 moves downward due to the thrust of the solenoid S1, it seats on the valve seat 22, closing the pressure control passage p2. Thus, the thrust of the solenoid S1 acts in a direction that closes the valve element 3.

[0066] Meanwhile, the pressure in the back-pressure chamber L4 acts to push the valve element 3 upward. Furthermore, when the pressure in the back-pressure chamber L4 increases, the upward force generated by this pressure overcomes the downward force generated by the solenoid S1, causing the valve element 3 to move upward and unseat from the valve seat 22, opening the pressure control passage p2. In other words, the pressure in the back-pressure chamber L4 acts to open the valve element 3. When the pressure in the back-pressure chamber L4 reaches the valve-opening pressure of the valve element 3, the valve element 3 opens the pressure control passage p2. This action of the valve element 3 unseating from and seating on the valve seat 22, opening and closing the pressure control passage p2, is also known as solenoid valve V switching.

[0067] Furthermore, in this embodiment, when the solenoid valve V is opened, the liquid in the backpressure chamber L4 flows through the pressure control passage p2 into the upper gap L5 formed between the head portion 2a of the second valve body 2B and the solenoid S1. This upper gap L5 communicates with the intermediate chamber L3 via a connecting passage p4 formed in the second valve body 2B. Thus, when the solenoid valve V is opened, the liquid flows from the backpressure chamber L4 into the upper gap L5 via the pressure control passage p2, and then from the upper gap L5 into the intermediate chamber L3 via the connecting passage p4. Furthermore, due to the connecting passage p4, the pressure in the upper gap L5 and the intermediate chamber L3 are approximately the same.

[0068] Next, the solenoid S1 involved in this embodiment includes: a coil 4, which is accommodated in the outer shell portion 11a of the piston rod 11 in an axial manner; a first fixed iron core 5, which is arranged on the upper side of the coil 4; a second fixed iron core 6, which is arranged on the lower side of the coil 4 and has a gap with the first fixed iron core 5; a first movable part 7 and a second movable part 8, which are arranged between the first fixed iron core 5 and the second fixed iron core 6 in a manner that can move up and down; a spring 9, which applies a downward force to the first movable part 7; a first limiting portion 90, which is integrally provided with the second movable part 8 and limits the downward movement of the first movable part 7 relative to the second movable part 8; and a second limiting portion 91, which is integrally provided with the second fixed iron core 6 and limits the downward movement of the second movable part 8.

[0069] Here, the direction along the centerline passing through the center of the coil 4 is the axial direction of the coil 4, and the top and bottom are the two axial sides of the coil 4. Therefore, it can be said that the first fixed core 5 is arranged at one axial end of the coil 4, and the second fixed core 6 is arranged at the other axial end of the coil 4. Furthermore, it can be said that the spring 9 biases the first movable member 7 toward the second fixed core 6, the first restricting portion 90 restricts movement of the first movable member 7 relative to the second movable member 8 toward the second fixed core 6, and the second restricting portion 91 restricts movement of the second movable member 8 toward the second fixed core 6.

[0070] Next, each component constituting the solenoid S1 according to this embodiment will be described in detail.

[0071] The coil 4 is integrally molded with a wiring harness 40 for supplying electricity using a molded resin. This wiring harness 40 extends from the inside of the piston rod 11 to the outside of the shock absorber D and is connected to a power source. Furthermore, the first fixed core 5, the second fixed core 6, the first movable member 7, and the second movable member 8 are each composed of a magnetic material. When current is applied to the coil 4, a magnetic flux is generated. This magnetic flux flows through the path of the first fixed core 5, the first movable member 7, the second movable member 8, the second fixed core 6, and the outer shell 11a, attracting the first movable member 7 upward toward the first fixed core 5 and the second movable member 8 downward toward the second fixed core 6.

[0072] An annular filling ring 41 made of a non-magnetic material is installed between the first and second stationary cores 5, 6. This filling ring 41 creates a magnetic gap between the first and second stationary cores 5, 6. Furthermore, a first movable member 7 and a second movable member 8 are arranged inside this filling ring 41. Both the first and second movable members 7, 8 are cylindrical with bottoms. The first movable member 7 is inserted inside the second movable member 8 so that it can move vertically (axially), and the second movable member 8 is inserted inside the filling ring 41 so that it can move vertically (axially).

[0073] like Figure 3 As shown, the second movable member 8, which serves as an outer cylinder, includes an outer bottom portion 8a and an outer cylinder portion 8b extending from the outer periphery of the outer bottom portion 8a. The outer bottom portion 8a faces downward (toward the second fixed core 6), and the outer cylinder portion 8b is in sliding contact with the inner periphery of the filling ring 41. Meanwhile, the first movable member 7, which serves as an inner cylinder, includes an inner bottom portion 7a and an inner cylinder portion 7b extending from the outer periphery of the inner bottom portion 7a. The inner bottom portion 7a faces downward (toward the second fixed core 6), and the inner cylinder portion 7b is in sliding contact with the inner periphery of the outer cylinder portion 8b.

[0074] The inner bottom 7a of the first movable member 7 and the outer bottom 8a of the second movable member 8 are formed with through-holes 7c and 8c extending through their respective wall thicknesses, allowing the first movable member 7 and the second movable member 8 to independently move up and down. Furthermore, a spring 9 is inserted inside the inner cylindrical portion 7b of the first movable member 7. In this embodiment, the spring 9 is a coil spring, with one end of the spring 9 abutting against the inner bottom 7a. Meanwhile, the other end of the spring 9 is supported by the first fixed core 5, and the spring 9 applies a downward force to the first movable member 7.

[0075] Next, the first and second limiting parts 90 and 91 are arranged above and below the outer bottom 8a of the second movable part 8. In the present embodiment, the first and second limiting parts 90 and 91 are respectively annular parts made of non-magnetic materials such as synthetic resin, rubber, and aluminum. The first limiting part 90 is pressed into the inner periphery of the outer cylindrical part 8b of the second movable part 8. In this way, the first limiting part 90 is opposite to the inner bottom 7a of the first movable part 7 in the upper and lower parts, and moves up and down as a whole with the second movable part 8. On the other hand, the second limiting part 91 is pressed into the inner periphery of the annular protrusion 6a of the second fixed iron core 6 into which the lower end of the second movable part 8 is inserted. In this way, the second limiting part 91 is opposite to the outer bottom 8a of the second movable part 8 in the upper and lower parts, and the second movable part 8 moves up and down relative to the second limiting part 91.

[0076] Furthermore, if the first movable member 7 moves downward relative to the second movable member 8, the inner bottom 7a of the first movable member 7 abuts the first restricting portion 90. This restricts the downward movement of the first movable member 7 relative to the second movable member 8, and the first movable member 7 and the second movable member 8 then move downward together. Furthermore, if the second movable member 8 moves downward, the outer bottom 8a of the second movable member 8 abuts the second restricting portion 91, preventing further downward movement.

[0077] A through hole is formed in the center portion of the second fixed iron core 6, and the shaft portion 3a of the valve core 3 is inserted through the through hole in a freely movable manner. Moreover, the front end of the shaft portion 3a abuts against the outer bottom 8a of the second movable part 8. In this way, when the coil 4 is de-energized, the first movable part 7 moves downward under the action of the spring 9 and abuts against the second movable part 8 through the first limiting portion 90, so that the valve core 3 is subjected to the downward force generated by the action of the spring 9. In contrast, if the coil 4 is energized, the first movable part 7 is attracted to the first fixed iron core 5 and the second movable part 8 is attracted to the second fixed iron core 6, then the spring 9 is compressed by the first movable part 7, and its action force is not transmitted to the valve core 3, but the valve core 3 is subjected to the downward force generated by the force of attracting the second movable part 8.

[0078] Furthermore, the first restricting portion 90 restricts the proximity of the inner bottom portion 7a of the first movable member 7 and the outer bottom portion 8a of the second movable member 8, which is opposed vertically (axially) thereto, thereby preventing the first movable member 7 and the second movable member 8 from being attracted to each other when power is supplied to the coil 4. Similarly, the second restricting portion 91 restricts the proximity of the outer bottom portion 8a of the second movable member 8 and the inner portion of the annular protrusion 6a of the second fixed core 6, which is opposed vertically (axially) thereto, thereby preventing the second movable member 8 from being attracted to the second fixed core 6 when power is supplied to the coil 4.

[0079] On the other hand, no restriction is provided between the first fixed core 5 and the first movable member 7. Therefore, when power is supplied to the coil 4, the first movable member 7 is attracted to the first fixed core 5. In this manner, if the first movable member 7 is attracted to the first fixed core 5 when power is supplied to the coil 4, the position of the first movable member 7 can be maintained stable. In this position, the first movable member 7 compresses the spring 9, and the force of the spring 9 is not transmitted to the second movable member 8. However, the first movable member 7 does not need to be attracted to the first fixed core 5 when power is supplied to the coil 4.

[0080] then, Figure 4 The relationship between the amount of current supplied to the solenoid S1 and the force applied by the solenoid S1 to the valve element 3 is shown. Figure 4 Here, Ia is the minimum current required to attract the first movable member 7 to the first fixed core 5 while the first movable member 7 is spaced away from the first fixed core 5, and Ib is the minimum current required to maintain the attracted state between the first fixed core 5 and the first movable member 7 after the first movable member 7 is attracted to the first fixed core 5. Ic will be described later.

[0081] First, when the current supplied to coil 4 is zero, that is, when solenoid S1 is de-energized, the first movable member 7 is pushed downward by the force of spring 9, abutting against the first restricting portion 90, and the second movable member 8 is pushed downward along with the valve element 3. Thus, when solenoid S1 is de-energized, the valve element 3 is subjected to the downward force generated by spring 9 via the second movable member 8, the first restricting portion 90, and the first movable member 7. Specifically, when solenoid S1 is de-energized, the solenoid S1 applies a downward force to the valve element 3 due to the force of spring 9.

[0082] Next, as the current supplied to solenoid S1 increases, the upward force pulling first movable member 7 toward first fixed iron core 5 increases, and the downward force pulling second movable member 8 toward second fixed iron core 6 also increases. In this case, in the range where the current supplied to solenoid S1 is less than Ia, although the biasing force of spring 9 is transmitted to valve element 3, part of the force of spring 9 biasing first movable member 7 downward is offset by the force pulling first movable member 7 upward (toward first fixed iron core 5). Therefore, in the range where the current is less than Ia, the greater the current supplied to solenoid S1, the smaller the downward force exerted by solenoid S1 on valve element 3.

[0083] On the other hand, when the current supplied to solenoid S1 increases, in the range where the current is above Ia, the first movable member 7 resists the force of the spring 9 and is attracted and held in place by the first fixed core 5. In this state, the force of the spring 9 is not transmitted to the second movable member 8, and only the force pulling the second movable member 8 toward the second fixed core 6 acts to push the valve element 3 downward. The downward force pulling the second movable member 8 increases in proportion to the current supplied to solenoid S1. Therefore, in the range where the current supplied to solenoid S1 is above Ia, the greater the current supplied to solenoid S1, the greater the downward force exerted by solenoid S1 on the valve element 3.

[0084] Conversely, when the current supplied to solenoid S1 is reduced while the first movable member 7 is attracted to the first fixed core 5 and the force of the spring 9 is not transmitted to the second movable member 8, the upward force attracting the first movable member 7 toward the first fixed core 5 decreases, and the downward force attracting the second movable member 8 toward the second fixed core 6 also decreases. Even in this case, in the range where the current supplied to solenoid S1 is Ib or greater, the first movable member 7 remains attracted to the first fixed core 5 and the force of the spring 9 is not transmitted to the second movable member 8. Therefore, in the range where the current supplied to solenoid S1 is Ib or greater, the downward force exerted by solenoid S1 on the valve element 3 decreases proportionally with the current supplied to solenoid S1.

[0085] On the other hand, when the current supplied to the solenoid S1 is reduced while the first movable member 7 is attracted to the first fixed iron core 5 and the force of the spring 9 is not transmitted to the second movable member 8, if the current falls below Ib, the force of the spring 9 releases the attraction between the first movable member 7 and the first fixed iron core 5, and the force of the spring 9 is transmitted to the second movable member 8. Therefore, in the region where the current is less than Ib, the smaller the current supplied to the solenoid S1, the greater the downward force exerted by the solenoid S1 on the valve element 3.

[0086] according to Figure 4 It can be seen that the minimum current Ib required to maintain the attraction between the first movable member 7 and the first fixed iron core 5 is less than the minimum current Ia required to attract the first movable member 7 to the first fixed iron core 5 in a separated state (Ia>Ib). Therefore, the force applied by the solenoid S1 to the valve core 3 relative to the current supplied to the solenoid S1 shows a hysteresis characteristic. In addition, for ease of understanding, Figure 4 The region where the amount of current supplied to the solenoid S1 is small is exaggeratedly displayed.

[0087] Furthermore, in this embodiment, to control the amount of current supplied to solenoid S1 and thereby control the force exerted by solenoid S1 on valve element 3, a current of at least Ia is first supplied to attract first movable member 7 to first fixed core 5. The current supplied to solenoid S1 is then controlled to a value greater than Ic, which is greater than Ib. This maintains the first movable member 7 attracted to first fixed core 5 while maintaining the amount of current supplied to solenoid S1. Consequently, the current supplied to solenoid S1 and the downward force exerted by solenoid S1 on valve element 3 are directly proportional, with the force increasing as the current supplied to solenoid S1 increases.

[0088] During normal operation (control), the force exerted by solenoid S1 on valve core 3 due to the magnetic force generated by energizing solenoid S1 is referred to as the "thrust" of solenoid S1. Specifically, the thrust of solenoid S1 can be controlled by controlling the amount of current supplied to solenoid S1. Furthermore, in this embodiment, the amount of current supplied to solenoid S1 and the thrust exerted by solenoid S1 on valve core 3 are directly proportional: the greater the supplied current, the greater the thrust, and the smaller the supplied current, the smaller the thrust.

[0089] On the other hand, in the event of a fault, where the solenoid S1 is de-energized, the valve core 3 is urged downward by the spring 9 of the solenoid S1. This force is predetermined by the spring constant and other specifications of the spring 9. Furthermore, the direction of the force of the spring 9 urging the valve core 3 during a fault (when de-energized) is the same as the direction of the thrust applied to the valve core 3 during normal operation.

[0090] Next, the operation of the shock absorber D including the electromagnetic valve V including the solenoid S1 according to the present embodiment will be described.

[0091] When the shock absorber D extends, the piston 10 moves upward within the cylinder 1, compressing the static expansion-side chamber L1 and increasing the pressure in the expansion-side chamber L1. The fluid in the expansion-side chamber L1 then flows through the pressure introduction passage p1 into the back-pressure chamber L4, increasing the pressure in the back-pressure chamber L4. When the pressure in the back-pressure chamber L4 reaches the valve opening pressure of the valve element 3, the valve element 3 (solenoid valve V) opens, allowing the fluid in the back-pressure chamber L4 to flow into the intermediate chamber L3 through the pressure control passage p2, the upper clearance L5, and the connecting passage p4. Consequently, when the shock absorber D extends, the pressure in the back-pressure chamber L4 is controlled to the valve opening pressure of the solenoid valve V.

[0092] Furthermore, when the damper D expands, the upward force due to the pressure in the expansion-side chamber L1 of the first and second valve bodies 2A and 2B exceeds the downward force due to the pressure in the back-pressure chamber L4. This causes the first and second valve bodies 2A and 2B to move upward. This creates a gap between the first valve body 2A and the valve seat member 16, allowing the liquid in the expansion-side chamber L1 to flow into the intermediate chamber L3 through this gap. The liquid in the intermediate chamber L3 then opens the expansion-side valve 20 and flows into the contraction-side chamber L2.

[0093] As a result, when the damper D expands, the first valve body portion 2A and the expansion-side valve 20 in the main valve body 2 open. The main valve body 2 and the expansion-side valve 20 exert resistance on the liquid flowing from the expansion-side chamber L1 to the compression-side chamber L2 in the main passage M. Consequently, when the damper D expands, the pressure in the expansion-side chamber L1 rises, and the damper D generates an expansion-side damping force that resists this expansion action.

[0094] Furthermore, when the amount of current supplied to the solenoid S1 is controlled normally, the greater the amount of current supplied to the solenoid S1, the greater the downward (closing) thrust exerted by the solenoid S1 on the valve element 3. Therefore, the greater the amount of current supplied to the solenoid S1, the higher the valve opening pressure of the valve element 3 (solenoid valve V), and thus the higher the pressure in the back-pressure chamber L4.

[0095] Furthermore, the pressure in the back-pressure chamber L4 acts downward (in the closing direction) on the second valve body 2B and the first valve body 2A. Therefore, the greater the current supplied to the solenoid S1, the higher the pressure in the back-pressure chamber L4, the higher the valve opening pressure of the first valve body 2A in the main valve body 2, and the greater the damping force on the extension side generated. In this way, under normal conditions, the damping force on the extension side can be adjusted by adjusting the valve opening pressure of the valve core 3 using the solenoid S1. In addition, Figure 2 、 3 The figure shows the state where the valve core 3 is normally open.

[0096] On the other hand, during a fault condition, when solenoid S1 is de-energized, the valve opening pressure of the valve element 3 (solenoid valve V) is determined by the force applied by spring 9. Therefore, the pressure in back-pressure chamber L4 during a fault condition is determined by the specifications of spring 9, and this determines the resulting expansion-side damping force. As described above, since the force applied by spring 9 is not transmitted to the valve element 3 during normal operation, the specifications of spring 9 can be freely set without regard to the normal expansion-side damping force.

[0097] Conversely, when the damper D contracts, the piston 10 moves downward within the cylinder 1, compressing the compression-side chamber L2. This increases the pressure in the compression-side chamber L2, causing the liquid in the compression-side chamber L2 to open the compression-side valve 21 and move toward the intermediate chamber L3. Furthermore, the liquid in the intermediate chamber L3 moves toward the back-pressure chamber L4 via the pressure-reducing passage p3. At this point, the pressure in the upper clearance L5 downstream of the valve element 3 is approximately the same as the pressure in the intermediate chamber L3, but higher than the pressure in the back-pressure chamber L4 upstream of the valve element 3. Therefore, the valve element 3 remains closed. Furthermore, in this state, the thrust of the solenoid S1 acts downward on the second valve body 2B via the valve element 3.

[0098] Furthermore, as described above, since the pressure in the intermediate chamber L3 acts only upward on the second valve body 2B, if the upward force generated by the pressure in the intermediate chamber L3 and other factors acting on the second valve body 2B exceeds the downward force generated by the thrust of the solenoid S1 and other factors, only the second valve body 2B moves upward. This creates a gap between the second valve body 2B and the first valve body 2A, and the liquid in the intermediate chamber L3 flows through this gap into the expansion-side chamber L1.

[0099] As described above, when the shock absorber D contracts, the contraction-side valve 21 and the second valve body portion 2B of the main valve body 2 open, and the contraction-side valve 21 and the main valve body 2 exert resistance on the liquid flowing from the contraction-side chamber L2 to the expansion-side chamber L1 in the main passage M. Consequently, when the shock absorber D contracts, the pressure in the contraction-side chamber L2 rises, and the shock absorber D generates a compression-side damping force that resists this contraction.

[0100] Furthermore, during normal operation, when the amount of current supplied to solenoid S1 is controlled, the greater the current supplied to solenoid S1, the greater the thrust of solenoid S1, and the greater the downward (closing) force acting on second valve body 2B. Therefore, as the current supplied to solenoid S1 increases, the greater the thrust of solenoid S1, the higher the valve-opening pressure of second valve body 2B in main valve body 2, and the greater the resulting compression-side damping force. Thus, during normal operation, the magnitude of the compression-side damping force is adjusted by regulating the force exerted downwardly on second valve body 2B via valve element 3 using solenoid S1.

[0101] On the other hand, during a fault condition, when the solenoid S1 is de-energized, the force of the spring 9 is transmitted to the second valve body 2B via the valve core 3. Therefore, the damping force on the compression side during a fault condition also depends on the specifications of the spring 9. As described above, during normal operation, the force of the spring 9 is not transmitted to the valve core 3. Therefore, the specifications of the spring 9 can be freely set without considering the damping force on the compression side during normal operation.

[0102] Next, the effects of the solenoid S1 according to the present embodiment, the electromagnetic valve V including the solenoid S1 , and the damper D including the electromagnetic valve V including the solenoid S1 will be described.

[0103] The solenoid S1 involved in this embodiment includes: a coil 4; a first fixed iron core 5, which is located at one end side of the coil 4 in the axial direction; a second fixed iron core 6, which is located at the other end side of the coil 4 in the axial direction and has a gap with the first fixed iron core 5; a first movable member 7, which is arranged between the first fixed iron core 5 and the second fixed iron core 6 and is attracted by the first fixed iron core 5 when power is supplied to the coil 4; a second movable member 8, which is arranged between the first fixed iron core 5 and the second fixed iron core 6 and is attracted by the second fixed iron core 6 when power is supplied to the coil 4; a spring 9, which urges the first movable member 7 toward the second fixed iron core 6; and a first limiting portion 90, which is integrally provided with the second movable member 8 and is made of a non-magnetic body to limit the movement of the first movable member 7 toward the second fixed iron core 6 relative to the second movable member 8.

[0104] According to the above structure, when the solenoid S1 is not energized, the first movable member 7 is urged toward the second fixed core 6 by the force of the spring 9. The movement of the first movable member 7 toward the second fixed core 6 relative to the second movable member 8 is restricted by the first restricting portion 90. As a result, the first movable member 7 and the second movable member 8 become one and move toward the second fixed core 6. Therefore, when the solenoid S1 is not energized, the force of the spring 9 is transmitted from the first movable member 7 to the second movable member 8.

[0105] On the other hand, when solenoid S1 is energized, the first movable member 7 is attracted by the first fixed core 5 and moves in the direction of attraction. The spring 9 is compressed by the first movable member 7, and the force of the spring 9 is not transmitted to the second movable member 8. Furthermore, when solenoid S1 is energized, the second movable member 8 is attracted by the second fixed core 6, and the greater the current supplied to solenoid S1, the greater the force that attracts the second movable member 8 toward the second fixed core 6.

[0106] Therefore, when solenoid S1 is energized, a force is applied to an object, such as the valve core 3, to attract the second movable member 8 as thrust. The greater the current supplied to solenoid S1, the greater the thrust applied to the object, while the smaller the current supplied to solenoid S1, the smaller the thrust applied to the object. Furthermore, when de-energized, the force of spring 9 acts on the object via the first movable member 7 and the second movable member 8. Because the direction of the force applied by spring 9 is the same as the direction of the force that attracts the second movable member 8 when solenoid S1 is energized, the above-described structure allows the object to be force applied in the same direction as when energized, even when solenoid S1 is de-energized.

[0107] Furthermore, according to the above structure, as described above, when the solenoid S1 is energized, the first movable member 7 moves toward the first fixed core 5 against the force of the spring 9. The force of the spring 9 is not transmitted to the second movable member 8, and thus to the valve core (object) 3. Therefore, the thrust of the solenoid S1 when energized and the force applied by the spring 9 to the object when de-energized can be freely set independently. In this embodiment, the spring 9 is a coil spring, but it may also be a spring other than a coil spring, such as a disc spring.

[0108] Furthermore, in the solenoid S1 of this embodiment, the first limiting portion 90, which limits the movement of the first movable member 7 relative to the second movable member 8 toward the second fixed core 6, is made of a non-magnetic material. This prevents the first movable member 7 and the second movable member 8 from adsorbing each other when power is supplied to the coil 4. Furthermore, in the solenoid S1 of this embodiment, the first limiting portion 90 and the second movable member 8 are integrally formed. Therefore, for example, when a PWM control current is applied to the solenoid S1, the first movable member 7 and the second movable member 8 vibrate, thereby preventing the first limiting portion 90 from vibrating in response to the vibration and thereby increasing high-frequency sound.

[0109] The solenoid S1 of this embodiment also includes a second restricting portion 91, which is integrally formed with the second fixed core 6 and is made of a non-magnetic material. This restricting portion 91 restricts movement of the second movable member 8 toward the second fixed core 6. This structure prevents the second movable member 8 from being attracted to the second fixed core 6 when current is supplied to the coil 4. Furthermore, for example, when a PWM control current is applied to the solenoid S1, vibration of the second movable member 8, which in turn excites the second restricting portion 91 and causes it to vibrate, can be prevented, thereby preventing the high-frequency sound from being amplified.

[0110] The solenoid S1 according to this embodiment also includes an annular filling ring 41, which is installed between the first and second fixed cores 5 and 6. Furthermore, the second movable member 8 has a bottomed cylindrical shape, including an outer bottom 8a and an outer cylindrical portion 8b extending from the outer periphery of the outer bottom 8a. The outer bottom 8a is inserted into the inner side of the filling ring 41, axially displaceable toward the second fixed core 6. Furthermore, the first movable member 7 also has a bottomed cylindrical shape, including an inner bottom 7a and an inner cylindrical portion 7b extending from the outer periphery of the inner bottom 7a. The inner bottom 7a faces the second fixed core 6, and the inner cylindrical portion 7b is inserted into the inner side of the outer cylindrical portion 8b of the second movable member 8, axially displaceable. Furthermore, a spring 9 is installed between the inner bottom 7a and the first fixed core 5, with one end of the spring inserted into the inner side of the inner cylindrical portion 7b of the first movable member 7.

[0111] According to the above configuration, by making the inner cylindrical portion 7b of the first movable member 7 and the outer cylindrical portion 8b of the second movable member 8 into magnetic materials, when the coil 4 is excited, a magnetic circuit passes through the first fixed core 5, the first movable member 7, the second movable member 8, and the second fixed core 6, thereby attracting the first movable member 7 toward the first fixed core 5 and the second movable member 8 toward the second fixed core 6. Furthermore, while ensuring space for accommodating the spring 9 inside the first movable member 7, the first movable member 7 and the second movable member 8 can be miniaturized, thereby miniaturizing the solenoid S1.

[0112] Furthermore, according to the above configuration, when the first movable member 7 moves toward the second fixed core 6, the inner bottom 7a of the first movable member 7 approaches the outer bottom 8a of the second movable member 8. Therefore, by providing the first restricting portion 90 to restrict movement in the approaching direction, movement of the first movable member 7 toward the second fixed core 6 relative to the second movable member 8 can be restricted. Furthermore, such placement of the first restricting portion 90 can be facilitated by, for example, arranging the first restricting portion 90 between the inner bottom 7a and the outer bottom 8a, as in the present embodiment. In other words, the above configuration facilitates placement of the first restricting portion 90.

[0113] Similarly, according to the above configuration, when the second movable member 8 moves toward the second fixed core 6, the outer bottom portion 8a of the second movable member 8 approaches the second fixed core 6. Therefore, by providing the second restricting portion 91 to restrict movement in the approaching direction, the second movable member 8 can be restricted from moving toward the second fixed core 6. Furthermore, such placement of the second restricting portion 91 can be facilitated by, for example, placing the second restricting portion 91 between the outer bottom portion 8a and the second fixed core 6, as in the present embodiment. In other words, the above configuration facilitates placement of the second restricting portion 91.

[0114] Furthermore, the first and second limiting portions 90 and 91 of the solenoid S1 of this embodiment are each annular members. Furthermore, the first limiting portion 90 is pressed into the inner circumference of the outer cylindrical portion 8b of the second movable member 8. On the other hand, the second limiting portion 91 is pressed into the inner circumference of the annular protrusion 6a of the second fixed core 6. Thus, in the solenoid S1 of this embodiment, since the first and second limiting portions 90 and 91 are integrally formed with the second movable member 8 or the second fixed core 6 by being pressed into place, even when the second movable member 8 and the second fixed core 6 are formed of a magnetic material and the first and second limiting portions 90 and 91 are formed of a non-magnetic material, the above-mentioned components can still be easily integrated.

[0115] Alternatively, the first restricting portion 90 may be integrally provided with the first movable member 7, and the structure for integrally providing the first restricting portion 90 with the first movable member 7 or the second movable member 8 may be modified as appropriate. Alternatively, the second restricting portion 91 may be integrally provided with the second movable member 8, and the structure for integrally providing the second restricting portion 91 with the second movable member 8 or the second fixed core 6 may be modified as appropriate. Figure 5-7 Modifications of the first and second restricting portions 90 and 91 are shown. Each modification of the solenoid S1 according to the present embodiment will be described in detail below.

[0116] like Figure 5 As shown, in the first modified example of the solenoid S1 of this embodiment, the inner bottom 7a of the first movable member 7 is a non-magnetic body, and the inner bottom 7a functions as a first restricting portion 90. In addition, in the first modified example, the second restricting portion 91 is integrally provided with the second movable member 8 and moves up and down together with the second movable member 8.

[0117] More specifically, the inner bottom portion 7a of the first movable member 7, which functions as the first restricting portion 90, includes a seat portion 90a positioned between the magnetic inner cylindrical portion 7b and the outer bottom portion 8a of the second movable member 8; and a fitting portion 90b that protrudes from the seat portion 90a and is pressed into the inner circumference of the inner cylindrical portion 7b. Meanwhile, the second restricting portion 91 includes a seat portion 91a positioned between the outer bottom portion 8a of the second movable member 8 and the second fixed core 6; and a fitting portion 91b that protrudes from the seat portion 91a and is pressed into the through-hole 8c formed in the outer bottom portion 8a.

[0118] According to the above configuration, when the first movable member 7 moves toward the second fixed core 6 relative to the second movable member 8, the seat portion 90a of the inner bottom portion 7a, functioning as the first restricting portion 90, abuts against the outer bottom portion 8a. This restricts movement of the first movable member 7 relative to the second movable member 8 toward the second fixed core 6, and the first movable member 7 and the second movable member 8 move integrally toward the second fixed core 6. Furthermore, when the second movable member 8 moves toward the second fixed core 6, the seat portion 91a of the second restricting portion 91 abuts against the second fixed core 6, restricting movement of the second movable member 8 toward the second fixed core 6.

[0119] Furthermore, since the seats 90a and 91a of the first and second restricting portions 90 and 91 are respectively formed of a non-magnetic material, it is possible to prevent the first movable member 7 and the second movable member 8 from being attracted to each other when the coil is energized, or to prevent the second movable member 8 from being attracted to the second fixed core 6. Furthermore, a hole 91c extending axially through the fitting portion 91b of the second restricting portion 91 is formed to prevent the through hole 8c of the outer bottom portion 8a from being closed by the fitting portion 91b.

[0120] Then, if Figure 6 As shown, in the second modified example of the solenoid S1 of this embodiment, a restricting member 93 is attached to the outer bottom 8a of the second movable member 8. This restricting member 93 includes an insertion shaft 93a, one end of which is press-fitted into a through-hole 8c formed in the outer bottom 8a, with one end protruding from the outer bottom 8a toward the second fixed core 6; and a seat 93b, which extends outward from the other end of the insertion shaft 93a and is positioned between the outer bottom 8a and the inner bottom 7a of the first movable member 7. Furthermore, the seat 93b functions as the first restricting member 90, while the one end of the insertion shaft 93a, which protrudes from the outer bottom 8a toward the second fixed core 6, functions as the second restricting member 91.

[0121] According to the above configuration, when the first movable member 7 moves toward the second fixed core 6 relative to the second movable member 8, the inner bottom portion 7a of the first movable member 7 abuts the seat portion 93b of the restriction member 93, which functions as the first restriction portion 90. This restricts the movement of the first movable member 7 relative to the second movable member 8 toward the second fixed core 6, and the first movable member 7 and the second movable member 8 move integrally toward the second fixed core 6. Furthermore, when the second movable member 8 moves toward the second fixed core 6, one end of the insertion shaft 93a, which functions as the second restriction portion 91, abuts the second fixed core 6, restricting the movement of the second movable member 8 toward the second fixed core 6.

[0122] Furthermore, since the restricting member 93, which includes the first and second restricting portions 90 and 91, is made of a non-magnetic material, it is possible to prevent the first movable member 7 and the second movable member 8 from being attracted to each other, or the second movable member 8 from being attracted to the second fixed core 6, due to the application of current to the coil. Furthermore, an axially extending hole 93c is formed in the insertion shaft 93a of the restricting member 93, and a notch 93d is formed at one end thereof, which extends into the hole 93c. This prevents the restricting member 93 from closing the through hole 8c of the outer bottom portion 8a.

[0123] Then, if Figure 7As shown, in the third modified example of the solenoid S1 of this embodiment, a restricting member 94 is attached to the outer bottom portion 8a of the second movable member 8. This restricting member 94 includes an insertion shaft 94a, one end of which is press-fitted into a through-hole 8c formed in the outer bottom portion 8a, with one end protruding from the outer bottom portion 8a toward the first fixed core 5; and a seat portion 94b, which extends outward from the other end of the insertion shaft 94a and is positioned between the outer bottom portion 8a and the second fixed core 6. Furthermore, the one end of the insertion shaft 94a, which protrudes from the outer bottom portion 8a toward the first fixed core 5, functions as the first restricting portion 90, while the seat portion 94b functions as the second restricting portion 91.

[0124] According to the above configuration, when the first movable member 7 moves toward the second fixed core 6 relative to the second movable member 8, the inner bottom portion 7a of the first movable member 7 abuts the front end of the insertion shaft 94a, which functions as the first restricting portion 90. This restricts the movement of the first movable member 7 relative to the second movable member 8 toward the second fixed core 6, and the first movable member 7 and the second movable member 8 move integrally toward the second fixed core 6. Furthermore, when the second movable member 8 moves toward the second fixed core 6, the seat portion 94b of the restricting member 94, which functions as the second restricting portion 91, abuts the second fixed core 6, and the movement of the second movable member 8 toward the second fixed core 6 is restricted.

[0125] Furthermore, since the restricting member 94, which includes the first and second restricting portions 90 and 91, is made of a non-magnetic material, it is possible to prevent the first movable member 7 and the second movable member 8 from being attracted to each other or the second movable member 8 from being attracted to the second fixed core 6 due to the application of current to the coil. Furthermore, an axially extending hole 94c is formed in the insertion shaft 94a of the restricting member 94, and a notch 94d is formed at one end thereof, which extends into the hole 94c. This prevents the restricting member 94 from closing the through hole 8c of the outer bottom portion 8a.

[0126] Thus, in the solenoid S1 of this embodiment, the first and second restricting portions 90 and 91 are integrally formed with the first movable member 7, the second movable member 8, or the second fixed core 6 by press-fitting. However, the method for achieving this is not limited to press-fitting; for example, screwing, bonding, or threaded connection may also be used.

[0127] Furthermore, the solenoid S1 of this embodiment, together with the valve core (valve body) 3 for opening and closing the pressure control passage p2, constitutes a solenoid valve V. Furthermore, when the coil 4 is energized, the solenoid S1 applies a force to the valve core (valve body) 3, which attracts the second movable member 8 toward the second fixed core 6, toward the valve core 3, closing the pressure control passage p2. Consequently, the valve opening pressure of the solenoid valve V can be adjusted by varying the amount of current supplied to the solenoid S1, setting the pressure upstream of the solenoid valve V as the valve opening pressure of the solenoid valve V.

[0128] Furthermore, as described above, in the solenoid S1 of this embodiment, the greater the current supplied when energized, the greater the thrust applied to the object. Therefore, in the solenoid valve V equipped with the solenoid S1 of this embodiment, the greater the current supplied to the solenoid S1, the higher the valve opening pressure of the valve element 3. Furthermore, as described above, in the solenoid S1 of this embodiment, even when de-energized, the spring 9 can still apply a force to the object in the same direction as the thrust applied when energized. Thus, in the solenoid valve V equipped with the solenoid S1 of this embodiment, the valve opening pressure when de-energized can be determined by the specifications of the spring 9.

[0129] Furthermore, a solenoid valve V including the solenoid S1 of this embodiment is provided in a damper D. In addition to the solenoid valve V, the damper D further comprises: a cylinder 1; a piston rod 11 inserted axially movable within the cylinder 1; a main passage M through which liquid flows when the cylinder 1 and the piston rod 11 move relative to each other in the axial direction; a main valve body 2 for opening and closing the main passage M; a pressure introduction passage p1 having a throttle O provided midway therein to reduce the pressure upstream of the main valve body 2 in the main passage M and then guide it to the rear surface of the main valve body 2; and a pressure control passage p2 connected to the pressure introduction passage p1 downstream of the throttle O and provided with the above-described solenoid valve V.

[0130] With this structure, when the cylinder 1 and piston rod 11 move relative to each other in the axial direction, the main valve body 2 exerts resistance on the fluid flowing through the main passage M, generating a damping force due to this resistance. Furthermore, since the back pressure of the main valve body 2 is set to the valve-opening pressure of the solenoid valve V, the back pressure of the main valve body 2 can be adjusted by varying the amount of current supplied to the solenoid S1. Furthermore, as the back pressure of the main valve body 2 increases, the first valve body portion 2A of the main valve body 2 becomes more difficult to open, and the resulting damping force on the extension side increases. Therefore, with this structure, the magnitude of the damping force on the extension side can be adjusted by varying the amount of current supplied to the solenoid S1.

[0131] Furthermore, as described above, in the solenoid valve V including the solenoid S1 of this embodiment, the greater the amount of current supplied to the solenoid S1, the higher the valve opening pressure of the solenoid valve V. Therefore, in the shock absorber D including the solenoid valve V including the solenoid S1 of this embodiment, the greater the amount of current supplied to the solenoid S1, the higher the back pressure of the main valve body 2 can be, and the greater the damping force on the expansion side can be generated.

[0132] Specifically, in the shock absorber D, since the generated extension-side damping force is reduced when the current supplied to the solenoid S1 is low, when the shock absorber D is used in a vehicle suspension, power consumption during normal driving can be reduced. Furthermore, this suppresses heat generation in the solenoid S1, minimizing temperature fluctuations in the shock absorber D. This reduces changes in the damping force characteristics (damping force characteristics relative to piston velocity) caused by changes in fluid temperature.

[0133] Furthermore, as described above, in the solenoid valve V including the solenoid S1 of this embodiment, the valve opening pressure when de-energized is determined by the specifications of the spring 9. Therefore, in a shock absorber D including the solenoid valve V including the solenoid S1 of this embodiment, the back pressure of the main valve body 2 can be increased even when the solenoid S1 is de-energized. This prevents insufficient damping force on the extension side of the shock absorber D even in the event of a malfunction caused by de-energization of the solenoid S1. Furthermore, in the shock absorber D, the pressure control passage p2 is simply provided as a passage connected to the backpressure chamber L4 and used to set the backpressure of the main valve body 2. This eliminates the need to switch the passage connected to the backpressure chamber L4 between energized and de-energized states of the solenoid S1. This reduces the structural complexity of the shock absorber D and reduces costs.

[0134] In this embodiment, the back pressure of the main valve body 2 is controlled by the solenoid valve V only when the damper D is extended. During contraction, the thrust of the solenoid S1 in the solenoid valve V directly acts on the main valve body 2 in the closing direction. However, it is of course also possible to control the back pressure of the main valve body by the solenoid valve V during contraction of the damper D.

[0135] Furthermore, the rod entering and exiting the cylinder 1 need not be a piston rod mounted with a piston, and the location of the main valve body for controlling back pressure via the solenoid valve V is not limited to the piston portion. For example, in the case of a shock absorber equipped with a reservoir as described above, the passage connecting the expansion-side chamber or the compression-side chamber with the reservoir can be used as the main passage, a main valve body can be provided, and back pressure within the main valve body can be controlled via the solenoid valve V. Furthermore, in the case of a unidirectional shock absorber in which liquid circulates unidirectionally through the expansion-side chamber, reservoir, and compression-side chamber during expansion and contraction, the circulation passage connecting the expansion-side chamber and the reservoir can be used as the main passage, a main valve body can be provided, and back pressure within the main valve body can be controlled via the solenoid valve V.

[0136] <Second embodiment>

[0137] Then, for example Figure 8 The solenoid S2 of the second embodiment of the present invention is described below. The solenoid S2 of this embodiment is used in the same electromagnetic valve as the solenoid S1 of the first embodiment. Figure 2 The solenoid S1 of the first embodiment is directly replaced with the solenoid S2 of this embodiment. The basic structure of the solenoid S2 of this embodiment is the same as that of the solenoid S1 of the first embodiment, and the common structures are denoted by the same reference numerals and detailed descriptions are omitted.

[0138] The major difference between the solenoid S2 of this embodiment and the solenoid S1 of the first embodiment lies in the reversed placement of the first and second movable members. More specifically, in this embodiment, the first movable member 7A comprises an inner cylindrical portion 7d and an outer cylindrical portion 7e arranged in two layers; a connecting portion 7f connecting one axial end of the inner and outer cylindrical portions 7d, 7e; and an inner bottom portion 7g located at the other end of the inner cylindrical portion 7d. With the inner bottom portion 7g facing downward (toward the second fixed core 6), the outer cylindrical portion 7e is in sliding contact with the inner circumference of the filling ring 41. Meanwhile, the second movable member 8A is a bottomed cylindrical magnetic body having an outer bottom portion 8d and an intermediate cylindrical portion 8e extending from the outer circumference of the outer bottom portion 8d. With the outer bottom portion 8d facing downward (toward the second fixed core 6), the intermediate cylindrical portion 8e is in sliding contact with the inner circumference of the outer cylindrical portion 7e of the first movable member 7A.

[0139] In the first movable component 7A, the outer and inner sides are made of different materials from the middle of the connecting portion 7f. The outer portion including the outer cylindrical portion 7e is a magnetic body, while the inner portion including the inner cylindrical portion 7d is a non-magnetic body. In addition, in the connecting portion 7f, the annular portion 7h connected to the inner cylindrical portion 7d is arranged so as to overlap with the upper side (the first fixed iron core 5 side) of the annular portion 7i connected to the outer cylindrical portion 7e. Furthermore, a spring 9 is inserted into the inner side of the inner cylindrical portion 7d. In this embodiment, the spring 9 is also a coil spring, and one end of the spring 9 abuts against the inner bottom 7g. On the other hand, the other end of the spring 9 is supported by the first fixed iron core 5, and the spring 9 applies a downward force to the inner bottom 7g of the first movable component 7A.

[0140] As described above, the annular portion 7h connected to the inner bottom portion 7g via the inner tube portion 7d overlaps the upper side of the annular portion 7i connected to the outer tube portion 7e. As a result, the upper annular portion 7h is constantly pressed against the lower annular portion 7i by the force of the spring 9. Therefore, the magnetic portion comprising the outer tube portion 7e and the non-magnetic portion comprising the inner tube portion 7d do not separate, and they remain integrated as the first movable component 7A. In other words, it can be said that the spring 9 applies a force downward (toward the second fixed core 6) to the entire first movable component 7A. If the upper side of the first movable component 7A (on the first fixed core 5 side) that houses the spring 9 is set as the spring chamber L6, then the spring chamber L6 is connected to the outside through the throttle passage p5.

[0141] More specifically, in this embodiment, the throttle passage p5 is formed by a throttle hole extending through the wall thickness of the inner bottom portion 7g of the first movable member 7A. Furthermore, as the first movable member 7A moves vertically (axially), the volume of the spring chamber L6 increases or decreases, and liquid corresponding to this increase or decrease in volume flows through the throttle passage p5. The resistance exerted by the throttle passage p5 on the flow of this liquid creates a damping force that hinders the movement of the first movable member 7A. This damping force counteracts the violent movement of the first movable member 7A, slowing its movement.

[0142] On the other hand, the second movable member 8A is formed with a connecting passage p6 that connects it top and bottom (the first fixed core 5 side and the second fixed core 6 side), allowing liquid to move relatively unimpeded within this connecting passage p6. Furthermore, the inner diameter of the intermediate cylindrical portion 8e of the second movable member 8A is larger than the outer diameter of the inner cylindrical portion 7d of the first movable member 7A, forming an annular gap between the two. Consequently, the space formed on the upper side of the intermediate cylindrical portion 8e (on the first fixed core 5 side) and the space formed between the outer bottom 8d and the inner bottom 7g form a continuous space. Furthermore, since the connecting passage p6 connects to this continuous space, it is possible to prevent liquid from being enclosed in this space and generating a damping force that would hinder the movement of the second movable member 8A.

[0143] In this embodiment, the connecting passage p6 is formed by a connecting hole that opens from the bottom of the recess 8f formed at a position facing the other end opening of the throttle passage p5 on the outer bottom 8d and leads to the lower side of the outer bottom 8d. Figure 8 As shown, even when the inner bottom 7g of the first movable member 7A abuts against the outer bottom 8d of the second movable member 8A, the throttle passage p5 is not closed and the second movable member 8A does not hinder the flow of liquid in the throttle passage p5.

[0144] Furthermore, in this embodiment, the outer cylindrical portion 7e is supported by the filling ring 41, and the first movable member 7A moves vertically (axially). Therefore, during movement, the first movable member 7A is prevented from becoming offset relative to the filling ring 41. The filling ring 41 is sandwiched between the first fixed core 5 and the second fixed core 6 and fixed relative to the first and second fixed cores 5 and 6. Therefore, the filling ring 41 prevents the first movable member 7A from shifting in a direction perpendicular to the centerline of the coil (radially).

[0145] Furthermore, the intermediate cylindrical portion 8e is supported by the outer cylindrical portion 7e of the first movable member 7A, allowing the second movable member 8A to move vertically (axially). Thus, in the solenoid S2 of this embodiment, the first movable member 7A is inserted into the filling ring 41, and the second movable member 8A is further inserted inside the first movable member 7A. This prevents radial displacement of the first movable member 7A when it is attracted to the first fixed core 5, and also prevents the second movable member 8A from being caught between the first movable member 7A and the filling ring 41 in the event of radial displacement. This eliminates the concern that the second movable member 8A would become caught between the first movable member 7A and the filling ring 41, thereby increasing sliding resistance during movement.

[0146] Furthermore, if Figure 8 As shown in FIG. 2( b ), in this embodiment, a protrusion 7j is provided on the inner circumference of the front end portion of the outer cylindrical portion 7e of the first movable member 7A, protruding toward the center thereof. This protrusion 7j holds the fluororesin sheet 70 against the inner circumference of the outer cylindrical portion 7e. This improves the sliding properties between the intermediate cylindrical portion 8e of the second movable member 8A and the outer cylindrical portion 7e of the first movable member 7A. The material of the sheet 70 can be any material with good sliding properties, not limited to fluororesin, and can be modified as appropriate. Furthermore, the sheet 70 can be omitted, allowing the intermediate cylindrical portion 8e to directly slide against the inner circumference of the outer cylindrical portion 7e.

[0147] Next, when the first movable member 7A moves downward relative to the second movable member 8A, the inner bottom 7g of the first movable member 7A contacts the outer bottom 8d of the second movable member 8A. Thus, the first restricting portion 90 restricts the downward movement of the first movable member 7A relative to the second movable member 8A, and the first movable member 7A and the second movable member 8A then move downward as a single unit. Specifically, the non-magnetic portion of the first movable member 7A, including the annular portion 7h, the inner cylindrical portion 7d, and the inner bottom 7g, functions as the first restricting portion 90 that restricts downward movement of the first movable member 7A relative to the second movable member 8A (toward the second fixed core 6).

[0148] The solenoid S2 of this embodiment also includes a second limiting portion 91, which limits downward movement of the second movable member 8A (toward the second fixed core 6). Similar to the first embodiment, this second limiting portion 91 is a non-magnetic annular member that is pressed into the inner circumference of the annular protrusion 6a of the second fixed core 6, into which the lower end of the second movable member 8A is inserted. Furthermore, if the second movable member 8A moves downward, its outer bottom portion 8d abuts against the second limiting portion 91, preventing further downward movement.

[0149] Furthermore, as in the first embodiment, a through hole is formed in the center portion of the second fixed core 6, and the shaft portion 3a of the valve core 3 is inserted into the through hole in a freely movable manner. Moreover, the front end of the shaft portion 3a abuts the outer bottom 8d of the second movable part 8A. Therefore, when the coil 4 is de-energized, the first movable part 7A moves downward under the action of the spring 9, and the first limiting portion 90 abuts the second movable part 8A, so that the valve core 3 is subjected to the downward force generated by the action of the spring 9. In contrast, if the first movable part 7A is attracted to the first fixed core 5 and the second movable part 8A is attracted to the second fixed core 6 by energizing the coil 4, the spring 9 is compressed by the first movable part 7A, and its action force is not transmitted to the valve core 3. However, the valve core 3 is subjected to the downward force generated by the force that attracts the second movable part 8A.

[0150] Furthermore, as in the first embodiment, the first and second restricting portions 90 and 91 prevent the first movable member 7A and the second movable member 8A from being attracted to each other when current is applied to the coil 4, or the second movable member 8A from being attracted to the second fixed core 6. On the other hand, no restricting portion is provided between the first fixed core 5 and the first movable member 7A, and the first movable member 7A is attracted to the first fixed core 5 when current is applied to the coil 4. In this manner, if the first movable member 7A is attracted to the first fixed core 5 when current is applied to the coil 4, the posture of the first movable member 7A is maintained stable. In this posture, the first movable member 7A compresses the spring 9, and the biasing force of the spring 9 is not transmitted to the second movable member 8A.

[0151] Furthermore, as described above, in this embodiment, the spring chamber L6 for accommodating the spring 9, formed on the first fixed core 5 side of the first movable member 7A, communicates with the outside via the throttle passage p5. Furthermore, when the first movable member 7A moves, a damping force is generated due to the resistance of the throttle passage p5. Therefore, even if the first movable member 7A is attracted to the first fixed core 5 when power is supplied to the coil 4, a loud attraction sound can be prevented. However, the first movable member 7A does not need to be attracted to the first fixed core 5 when power is supplied to the coil 4. In this case, the throttle passage p5 can be replaced with a connecting passage.

[0152] As with the solenoid S1 of the first embodiment, the relationship between the amount of current supplied to the solenoid S2 of this embodiment and the force applied by the solenoid S2 to the valve element (object) 3 is as follows: Figure 4 The operation of the shock absorber including the electromagnetic valve including the solenoid S2 according to this embodiment is also the same as the operation of the shock absorber D including the electromagnetic valve V including the solenoid S1 according to the first embodiment.

[0153] The following describes the effects of the solenoid S2 of this embodiment. Since the solenoid S1 of the first embodiment has the same structure and effects as the solenoid S1, detailed descriptions are omitted here. Furthermore, the effects of the solenoid valve and the damper incorporating the solenoid valve of this embodiment are similar to those of the solenoid S1, the solenoid valve V, and the damper D incorporating the solenoid valve V of the first embodiment, and therefore detailed descriptions are omitted here.

[0154] The solenoid S2 involved in this embodiment includes: a coil; a first fixed iron core 5, which is located at one end side of the coil in the axial direction; a second fixed iron core 6, which is located at the other end side of the coil in the axial direction and has a gap with the first fixed iron core 5; a first movable part 7A, which is arranged between the first fixed iron core 5 and the second fixed iron core 6 and is attracted by the first fixed iron core 5 when power is supplied to the coil; a second movable part 8A, which is arranged between the first fixed iron core 5 and the second fixed iron core 6 and is attracted by the second fixed iron core 6 when power is supplied to the coil; a spring 9, which applies force to the first movable part 7A toward the second fixed iron core 6; and a first limiting part 90, which is integrally provided with the first movable part 7A and is made of a non-magnetic body to limit the movement of the first movable part 7A toward the second fixed iron core 6 relative to the second movable part 8A.

[0155] According to the above structure, when the solenoid S2 is not energized, the first movable member 7A is urged toward the second fixed core 6 by the force of the spring 9. However, the movement of the first movable member 7A toward the second fixed core 6 relative to the second movable member 8A is restricted by the first restricting portion 90. As a result, the first movable member 7A and the second movable member 8A move together toward the second fixed core 6. Therefore, when the solenoid S2 is not energized, the force of the spring 9 is transmitted from the first movable member 7A to the second movable member 8A.

[0156] On the other hand, when solenoid S2 is energized, the first movable member 7A is attracted by the first fixed core 5 and moves in the direction of attraction. The spring 9 is compressed by the first movable member 7A, and the force of the spring 9 is not transmitted to the second movable member 8A. Furthermore, when solenoid S2 is energized, the second movable member 8A is attracted by the second fixed core 6. The greater the current supplied to solenoid S2, the greater the force that attracts the second movable member 8A toward the second fixed core 6.

[0157] Therefore, when solenoid S2 is energized, a force is applied to an object, such as the valve core 3, to attract the second movable member 8A. The greater the current supplied to solenoid S2, the greater the thrust applied to the object, while the smaller the current supplied to solenoid S2, the smaller the thrust applied to the object. Furthermore, when de-energized, the force of spring 9 acts on the object via the first movable member 7A and the second movable member 8A. The direction of the force applied by spring 9 is the same as the direction of the force that attracts the second movable member 8A when solenoid S2 is energized. Therefore, according to the above structure, even when solenoid S2 is de-energized, it can still apply force to the object in the same direction as when energized.

[0158] Furthermore, according to the above structure, as described above, when solenoid S2 is energized, the first movable member 7A moves toward the first fixed core 5 against the force of spring 9. The force of spring 9 is not transmitted to the second movable member 8A, and thus to the valve core (object) 3. Therefore, the thrust of solenoid S2 when energized and the force applied by spring 9 to the object when de-energized can be freely set independently. While spring 9 is a coil spring in this embodiment, it may also be a spring other than a coil spring, such as a disc spring.

[0159] Furthermore, in the solenoid S2 of this embodiment, the first limiting portion 90, which limits the movement of the first movable member 7A relative to the second movable member 8A toward the second fixed core 6, is made of a non-magnetic material. This prevents the first movable member 7A and the second movable member 8A from adsorbing each other when power is applied to the coil. Furthermore, in the solenoid S2 of this embodiment, the first limiting portion 90 is integrally formed with the first movable member 7A. This prevents, for example, the first movable member 7A and the second movable member 8A from vibrating when a PWM control current is applied to the solenoid S2, thereby preventing the first limiting portion 90 from vibrating in response to the vibration and causing an increase in high-frequency sound.

[0160] The solenoid S2 of this embodiment also includes a second restricting portion 91 integrally formed with the second fixed core 6, which restricts movement of the second movable member 8A toward the second fixed core 6. This structure prevents the second movable member 8A from becoming attracted to the second fixed core 6 when current is applied to the coil. Furthermore, for example, when a PWM control current is applied to the solenoid S2, the second movable member 8A vibrates, which in turn excites the second restricting portion 91 and causes it to vibrate, thereby amplifying high-frequency sound.

[0161] The solenoid S2 of this embodiment also includes an annular filling ring 41 mounted between the first fixed core 5 and the second fixed core 6. Furthermore, the first movable member 7A includes an inner cylindrical portion 7d and an outer cylindrical portion 7e arranged in two layers; a connecting portion 7f connecting one axial end of the inner cylindrical portion 7d and the outer cylindrical portion 7e; and an inner bottom portion 7g located at the other end of the inner cylindrical portion 7d. The inner bottom portion 7g is slidably inserted into the inner side of the filling ring 41 toward the second fixed core 6. Meanwhile, the second movable member 8A has a bottomed cylindrical shape and includes an outer bottom portion 8d and an intermediate cylindrical portion 8e extending from the outer periphery of the outer bottom portion 8d and having an inner diameter greater than that of the inner cylindrical portion 7d of the first movable member 7A. The outer bottom portion 8d faces the second fixed core 6, and the intermediate cylindrical portion 8e is slidably inserted into the inner side of the outer cylindrical portion 7e of the first movable member 7A. Furthermore, the spring 9 is attached between the inner bottom portion 7 g and the first fixed core 5 so that one end side thereof is inserted into the inner side of the inner cylindrical portion 7 d of the first movable member 7A.

[0162] According to the above configuration, by forming the outer cylindrical portion 7e of the first movable member 7A and the intermediate cylindrical portion 8e of the second movable member 8A into magnetic materials, when the coil is excited, a magnetic circuit passes through the first fixed core 5, the first movable member 7A, the second movable member 8A, and the second fixed core 6, thereby attracting the first movable member 7A toward the first fixed core 5 and the second movable member 8A toward the second fixed core 6. Furthermore, space for accommodating the spring 9 can be ensured inside the inner cylindrical portion 7d of the first movable member 7A.

[0163] Furthermore, according to the above configuration, when the first movable member 7A moves toward the second fixed core 6, the inner bottom 7g of the first movable member 7A approaches the outer bottom 8d of the second movable member 8A. Therefore, by providing the first restricting portion 90 to restrict movement in the approaching direction, the first movable member 7A can be restricted from moving toward the second fixed core 6 relative to the second movable member 8A. Furthermore, such configuration of the first restricting portion 90 can be facilitated by, for example, making the inner bottom 7g of the first movable member 7A function as the first restricting portion 90 and contacting it with the outer bottom 8d of the second movable member 8A, as in the present embodiment. In other words, the above configuration facilitates the placement of the first restricting portion 90.

[0164] Similarly, according to the above configuration, when the second movable member 8A moves toward the second fixed core 6, the outer bottom portion 8d of the second movable member 8A approaches the second fixed core 6. Therefore, by providing a second restricting portion 91 to restrict movement in the approaching direction, the second movable member 8A can be restricted from moving toward the second fixed core 6. Furthermore, such placement of the second restricting portion 91 can be facilitated by, for example, placing the second restricting portion 91 between the outer bottom portion 8a and the second fixed core 6, as in the present embodiment. In other words, the above configuration facilitates placement of the second restricting portion 91.

[0165] Furthermore, in the solenoid S2, the intermediate cylindrical portion 8e of the second movable member 8A is slidably inserted inside the outer cylindrical portion 7e of the first movable member 7A, which is slidably inserted into the filling ring 41. Thus, as the first movable member 7A is inserted into the filling ring 41, the second movable member 8A is further inserted inside the first movable member 7A. This eliminates the risk of radial movement of the first movable member 7A when attracted to the first fixed core 5, preventing the second movable member 8A from becoming sandwiched between the first movable member 7A and the filling ring 41. This ensures smooth vertical movement of the second movable member 8A. As a result, when the force attracting the second movable member 8A is applied as thrust to an object, as described above, hysteresis in the thrust's characteristics relative to the amount of current supplied to the solenoid S2 is suppressed, making thrust control easier.

[0166] In this embodiment, the portion from the inner bottom portion 7g to the inner cylindrical portion 7d of the first movable member 7A is made of a non-magnetic material and functions as the first restricting portion 90. This allows the solenoid S2 to be made lighter.

[0167] However, similar to the solenoid S1 of the first embodiment, in the solenoid S2 of this embodiment, the first and second limiting parts 90 and 91 can still be appropriately changed. For example, only the inner bottom 7g of the first movable part 7A can be made of a non-magnetic material to function as the first limiting part 90. In addition, the first limiting part 90 is an annular part made of a non-magnetic material and is pressed into the inner periphery of the intermediate cylindrical part 8e of the second movable part 8A. Figure 6 , the limiting parts 93, 94 shown in FIG. 7 are mounted on the outer bottom 8d of the second movable part 8A.

[0168] While the preferred embodiments of the present invention have been described in detail above, modifications, variations, and alterations may be made without departing from the scope of the claims.

[0169] This application claims priority based on Japanese Patent Application No. 2019-163880 filed with the Japan Patent Office on September 9, 2019, the entire contents of which are incorporated herein by reference.

[0170] Explanation of symbols

[0171] D-buffer

[0172] M Main Channel

[0173] L6 spring chamber

[0174] O Restrictor

[0175] p1 pressure inlet channel

[0176] p2 pressure control channel

[0177] p5 throttle channel

[0178] S1, S2 solenoids

[0179] V solenoid valve

[0180] 1 cylinder

[0181] 2 Main valve body

[0182] 3. Valve core (valve body)

[0183] 4 coils

[0184] 5 First fixed core

[0185] 6 Second fixed core

[0186] 6a Annular protrusion

[0187] 7, 7A First movable part

[0188] 7a, 7g inside bottom

[0189] 7b, 7d inner tube

[0190] 7e outer tube

[0191] 7f Connection

[0192] 8, 8A Second movable part

[0193] 8a, 8d outside bottom

[0194] 8b outer cylinder part

[0195] 8c through hole

[0196] 8e intermediate cylinder

[0197] 9 Spring

[0198] 11 Piston rod (rod)

[0199] 41 Filling Ring

[0200] 90 First Restriction Section

[0201] 91 Second Restriction

[0202] 91a Seat

[0203] 91b chimeric part

[0204] 93, 94 Restricted components

[0205] 93a, 94a Insertion shaft

[0206] 93b, 94b seat

Claims

1. Solenoid, where have: Coil; a first fixed iron core, the first fixed iron core being located at one end side of the coil in an axial direction; a second fixed iron core, the second fixed iron core being located at the other end side of the coil axial direction and having a gap with the first fixed iron core; a first movable member disposed between the first fixed iron core and the second fixed iron core and attracted by the first fixed iron core when power is supplied to the coil; a second movable member disposed between the first fixed iron core and the second fixed iron core and attracted by the second fixed iron core when power is supplied to the coil; a spring for applying force to the first movable member toward the second fixed core; a first limiting portion, the first limiting portion being integrally provided with the first movable member or the second movable member and being formed of a non-magnetic body to limit the movement of the first movable member toward the second fixed core relative to the second movable member; as well as an annular filling ring, the annular filling ring being installed between the first fixed iron core and the second fixed iron core, The first movable member comprises: an inner cylinder portion and an outer cylinder portion arranged in two layers; a connecting portion connecting the inner cylinder portion and one axial end of the outer cylinder portion; and an inner bottom portion located at the other end of the inner cylinder portion, the inner bottom portion being slidably inserted into the inner side of the filling ring toward the second fixed core side. The second movable member is in the shape of a bottomed cylinder, comprising an outer bottom and an intermediate cylinder portion standing upright on the outer periphery of the outer bottom and having an inner diameter larger than the outer diameter of the inner cylinder portion, the outer bottom facing the second fixed core, and the intermediate cylinder portion being slidably inserted into the inner side of the outer cylinder portion. The spring is installed between the inner bottom portion and the first fixed core so that one end side thereof is inserted into the inner side of the inner cylindrical portion.

2. The solenoid of claim 1, wherein: The portion from the inner bottom portion to the inner cylindrical portion is made of a non-magnetic material and functions as the first restricting portion.

3. Solenoid, where have: Coil; a first fixed iron core, the first fixed iron core being located at one end side of the coil in an axial direction; a second fixed iron core, the second fixed iron core being located at the other end side of the coil axial direction and having a gap with the first fixed iron core; a first movable member disposed between the first fixed iron core and the second fixed iron core and attracted by the first fixed iron core when power is supplied to the coil; a second movable member disposed between the first fixed iron core and the second fixed iron core and attracted by the second fixed iron core when power is supplied to the coil; a spring for applying force to the first movable member toward the second fixed core; a first limiting portion, the first limiting portion being integrally provided with the first movable member or the second movable member and being formed of a non-magnetic body to limit the movement of the first movable member toward the second fixed core relative to the second movable member; a second limiting portion, the second limiting portion being integrally provided with the second movable member or the second fixed core and being formed of a non-magnetic body to limit the movement of the second movable member toward the second fixed core; as well as an annular filling ring, the annular filling ring being installed between the first fixed iron core and the second fixed iron core, The second movable member is in the shape of a bottomed cylinder, having an outer bottom and an outer cylinder portion standing upright on the outer peripheral edge of the outer bottom, the outer bottom being inserted into the inner side of the filling ring in an axially movable manner toward the second fixed iron core side, The first movable member is in the shape of a bottomed cylinder, having an inner bottom and an inner cylinder portion standing upright on the outer peripheral edge of the inner bottom, the inner bottom facing the second fixed core, and the inner cylinder portion is inserted into the inner side of the outer cylinder portion in an axially movable manner. The spring is installed between the inner bottom portion and the first fixed core so that one end side thereof is inserted into the inner side of the inner cylindrical portion.

4. The solenoid of claim 3, wherein: have: a limiting component, the limiting component being mounted on the outer bottom, The limiting component includes: an insertion shaft, one end of which is pressed into a through hole formed in the outer bottom portion in a state of protruding from the outer bottom portion toward the second fixed iron core; and a seat portion, which protrudes from the other end of the insertion shaft toward the outer peripheral side and is located between the outer bottom portion and the inner bottom portion. The seat portion functions as the first restriction portion. One end portion of the insertion shaft protruding from the outer bottom portion toward the second fixed iron core functions as the second restricting portion.

5. The solenoid of claim 3, wherein: have: a limiting component, the limiting component being mounted on the outer bottom, The limiting component includes: an insertion shaft, one end of which is pressed into a through hole formed in the outer bottom portion in a state of protruding from the outer bottom portion toward the first fixed iron core; and a seat portion, which protrudes from the other end of the insertion shaft toward the outer peripheral side and is located between the outer bottom portion and the second fixed iron core. One end portion of the insertion shaft protruding from the outer bottom portion toward the first fixed core functions as the first restricting portion. The seat portion functions as the second restricting portion.

6. The solenoid of claim 3, wherein: The second restricting portion includes a seat portion located between the outer bottom portion and the second fixed iron core, and an engaging portion protruding from the seat portion and press-fitted into a through-hole formed in the outer bottom portion.

7. Solenoid, where have: Coil; a first fixed iron core, the first fixed iron core being located at one end side of the coil in an axial direction; a second fixed iron core, the second fixed iron core being located at the other end side of the coil axial direction and having a gap with the first fixed iron core; a first movable member disposed between the first fixed iron core and the second fixed iron core and attracted by the first fixed iron core when power is supplied to the coil; a second movable member disposed between the first fixed iron core and the second fixed iron core and attracted by the second fixed iron core when power is supplied to the coil; a spring for applying force to the first movable member toward the second fixed core; a first limiting portion, the first limiting portion being integrally provided with the first movable member or the second movable member and being formed of a non-magnetic body to limit the movement of the first movable member toward the second fixed core relative to the second movable member; a second limiting portion, the second limiting portion being integrally provided with the second movable member or the second fixed core and being formed of a non-magnetic body to limit the movement of the second movable member toward the second fixed core; as well as an annular filling ring, the annular filling ring being installed between the first fixed iron core and the second fixed iron core, The first movable member comprises: an inner cylinder portion and an outer cylinder portion arranged in two layers; a connecting portion connecting the inner cylinder portion and one axial end of the outer cylinder portion; and an inner bottom portion located at the other end of the inner cylinder portion, the inner bottom portion being slidably inserted into the inner side of the filling ring toward the second fixed core side. The second movable member is in the shape of a bottomed cylinder, comprising an outer bottom and an intermediate cylinder portion standing upright on the outer periphery of the outer bottom and having an inner diameter larger than the outer diameter of the inner cylinder portion, the outer bottom facing the second fixed core, and the intermediate cylinder portion being slidably inserted into the inner side of the outer cylinder portion. The spring is installed between the inner bottom portion and the first fixed core so that one end side thereof is inserted into the inner side of the inner cylindrical portion.

8. The solenoid of claim 7, wherein: The second fixed iron core has an annular protrusion, the inner side of which is inserted into the end portion of the second movable member on the second fixed iron core side. The second restricting portion is an annular member and is press-fitted into the inner periphery of the annular projection.

9. A solenoid valve comprising the solenoid according to claim 1, 3 or 7, and arranged midway in a pressure control passage, wherein: have: a valve body, the valve body being used to open and close the pressure control channel, The solenoid applies a force to the valve body in a direction to close the pressure control passage, which is generated when the coil is energized and attracts the second movable member toward the second fixed core.

10. A buffer comprising the solenoid valve according to claim 9, wherein: have: cylinder; a rod, the rod being inserted into the cylinder in an axially movable manner; a main channel, wherein the main channel allows liquid to flow through when the cylinder and the rod move relative to each other in the axial direction; a main valve body, the main valve body being used to open and close the main channel; a pressure introduction channel provided with a throttle in the middle thereof, which reduces the pressure on the upstream side of the main valve body of the main channel and then guides the pressure to the back side of the main valve body; and The pressure control passage is connected to the downstream of the throttle of the pressure introduction passage and is provided with the solenoid valve.

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