solenoids, electromagnetic valves and dampers

Abstract

The solenoid (S1) of the present invention comprises: a first fixed iron core (5) and a second fixed iron core (6), respectively located at one end and the other end of the axial direction of the coil (4); a first movable iron core (7) and a second movable iron core (8), located between the first fixed iron core (5) and the second fixed iron core (6), which are attracted by the first fixed iron core (5) and the second fixed iron core (6) respectively when the coil (4) is energized; a spring (9) that applies force to the first movable iron core (7) toward the second fixed iron core (6); and a leaf spring (90) that restricts the movement of the first movable iron core (7) toward the second fixed iron core (6) relative to the second movable iron core (8), and restricts the movement of the first movable iron core (7) relative to the first fixed iron core (5) and the second fixed iron core (6) in a direction orthogonal to the axial direction of the coil (4).

Description

Technical Field

[0001] The present invention relates to a solenoid, a solenoid valve having a solenoid, and a buffer having a solenoid valve having a solenoid. Background Technology

[0002] In the past, solenoids consisted of a coil and a movable iron core. When the coil was energized, the movable iron core generated a magnetic field, producing magnetic flux that was attracted toward the axial side of the coil. While applying the force attracting the movable iron core as a thrust to other components (target objects), the thrust could be varied according to the amount of current flowing through it. Such solenoids were used, for example, in solenoid valves.

[0003] Furthermore, this solenoid valve, positioned midway through the pressure control channel, includes a valve body (for opening and closing the pressure control channel) and a spring that applies force to the valve body in the opening direction, while the solenoid applies a closing force to the valve body. According to this solenoid valve, the greater the current supplied to the solenoid, the higher the opening pressure of the solenoid valve, thus increasing the pressure on the upstream side of the solenoid valve. This type of solenoid valve is used, for example, in a buffer.

[0004] Furthermore, this buffer, in addition to the solenoid valve, also has a main channel for liquid flow during buffer extension and retraction, and a main valve body for opening and closing the main channel. A pressure control channel equipped with the solenoid valve is connected to a back pressure chamber formed on the back of the main valve body. According to this buffer, the greater the current supplied to the solenoid and the higher the opening pressure of the solenoid valve, the higher the back pressure (pressure in the back pressure chamber) of the main valve body, and the greater the damping force generated (e.g., Patent Document 1).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-173716 Invention Summary

[0008] The problem that the invention aims to solve

[0009] Therefore, when applying dampers to vehicle suspensions, it is preferable to reduce the damping force generated during normal driving while maintaining good ride comfort on roads with good conditions. Furthermore, in dampers equipped with solenoid valves containing conventional solenoids, reducing the current supplied to the solenoid reduces the generated damping force, thus suppressing power consumption during normal driving and saving energy. Nevertheless, in conventional dampers, if a power failure occurs in the solenoid, the solenoid valve opens fully and the back pressure of the main valve body becomes minimal, resulting in insufficient damping force during the failure.

[0010] Therefore, the solenoid valve installed in the buffer described in Japanese Patent Application Publication No. 2014-173716 has two opening and closing parts for opening and closing the pressure control channel. Furthermore, one opening and closing part is forced in the opening direction by a spring, and functions as an opening and closing part under pressure control when a closing force is applied by a solenoid. On the other hand, when the solenoid is not energized, the other opening and closing part, in a state where one of the opening and closing parts is fully open due to the spring force, closes the downstream side of the portion of the pressure control channel opened and closed by one of the opening and closing parts.

[0011] Furthermore, the aforementioned buffer also features a fault channel connected between the portion of the pressure control channel that is opened and closed by one of the opening and closing parts and the portion that is opened and closed by the other, with a passive valve installed in between. Thus, when the solenoid is not energized, if the pressure control channel is closed by the other opening and closing part of the solenoid valve, the liquid in the back pressure chamber will flow through the fault channel, and the back pressure of the main valve body will be set to the opening pressure of the passive valve. Therefore, even in conventional buffers, the damping force of the buffer will not be insufficient in the event of a fault.

[0012] However, as shown in the buffer above, two channels are provided as the channel connecting to the back pressure chamber to set the back pressure of the main valve body: a pressure control channel and a fault channel. The channel connected to the back pressure chamber must be switched when the solenoid is energized and de-energized. In this case, the buffer structure becomes complex and incurs considerable cost. However, when a spring applies force to the solenoid valve body in the closing direction and a solenoid applies a thrust to the valve body in the opening direction, although switching the channel connected to the back pressure chamber when the solenoid is energized and de-energized is not required, the current supplied to the solenoid must be increased to reduce the generated damping force, thus increasing power consumption during normal operation.

[0013] In other words, when using solenoids in variable-force solenoid valves for buffers, it is desirable to reduce the thrust applied to the valve body or other target when the current supplied to the solenoid is small. Furthermore, it is sometimes desirable to apply a force in the same direction as the thrust to the target even when the solenoid is not energized, which is not possible with conventional solenoids. Therefore, using conventional solenoids in variable-force solenoid valves for buffers results in problems such as complex buffer structure or increased power consumption during normal vehicle operation.

[0014] Therefore, the present invention is proposed to solve such problems, and its object is to provide a solenoid, a solenoid valve and a buffer, wherein when the current supplied to the solenoid is small, the thrust exerted by the solenoid on the target can be reduced, and even when the solenoid is not energized, the solenoid can exert force on the target in the same direction as the thrust when energized.

[0015] Solution for solving the problem

[0016] The solenoid that solves the above-mentioned problem includes: a first fixed iron core and a second fixed iron core, respectively located at one end and the other end of the axial direction of the coil; a first movable iron core and a second movable iron core, located between the first fixed iron core and the second fixed iron core, which are attracted by the first fixed iron core and the second fixed iron core respectively when the coil is energized; a spring that applies force to the first movable iron core toward the second fixed iron core; and a limiting part that restricts the movement of the first movable iron core relative to the second movable iron core toward the second fixed iron core, wherein the movement of the first movable iron core relative to the first fixed iron core and the second fixed iron core in a direction orthogonal to the axial direction of the coil is restricted.

[0017] According to the above structure, when the solenoid is not energized, the first movable iron core moves towards the second fixed iron core under the force of the spring. When the movement of the first movable iron core relative to the second movable iron core towards the second fixed iron core is restricted by the limiting part, the force of the spring is transmitted from the first movable iron core to the second movable iron core through the limiting part. On the other hand, when the solenoid is energized, if the first movable iron core is attracted by the first fixed iron core and moves in the direction of attraction, the spring is compressed by the first movable iron core, and the force of the spring is not transmitted to the second movable iron core. Furthermore, when the solenoid is energized, the second movable iron core is attracted by the second fixed iron core, and the greater the current supplied to the solenoid, the greater the force that attracts the second movable iron core to the second fixed iron core.

[0018] Therefore, if the force attracting the second movable iron core is applied as a thrust to the target when the solenoid is energized, the greater the current supplied to the solenoid, the greater the thrust applied to the target; conversely, the smaller the current supplied to the solenoid, the smaller the thrust applied to the target. Furthermore, when not energized, the spring force acts on the target via the first movable iron core, the limiting part, and the second movable iron core. Since the direction of the spring force is the same as the direction of the force attracting the second movable iron core when the solenoid is energized, according to the above structure, even when the solenoid is not energized, a force can be applied to the target in the same direction as when it is energized.

[0019] Furthermore, according to the above structure, since the first movable iron core is restricted from moving radially relative to the first fixed iron core and the second fixed iron core in a direction orthogonal to the axial direction of the coil, the movement of the second movable iron core is not hindered by the first movable iron core, which is radially offset, thus ensuring smooth up-and-down movement of the second movable iron core.

[0020] Alternatively, the solenoid may have an annular filling ring installed between the first fixed iron core and the second fixed iron core. The second movable iron core is a bottomed cylindrical shape with an outer bottom and an outer cylinder portion. The outer bottom is axially movable and inserted into the inner side of the filling ring with the second fixed iron core side facing it. The first movable iron core is a bottomed cylindrical shape with an inner bottom and an inner cylinder portion with an outer diameter smaller than the inner diameter of the outer cylinder portion. The inner bottom is axially movable and inserted into the inner side of the outer cylinder portion with the second fixed iron core side facing it. The spring is installed between the inner bottom and the first fixed iron core with one end inserted into the inner side of the inner cylinder portion.

[0021] According to the above structure, when the coil is energized, the magnetic circuit passes through the first fixed iron core, the first movable iron core, the second movable iron core, and the second fixed iron core, thereby attracting the first movable iron core to the first fixed iron core and attracting the second movable iron core to the second fixed iron core. Furthermore, it is possible to ensure the spring's accommodating space inside the first movable iron core while miniaturizing the solenoid.

[0022] Furthermore, according to the above structure, when the first movable core moves toward the second fixed core, the inner bottom of the first movable core approaches the outer bottom of the second movable core. Therefore, if a limiting part is provided to restrict movement in this approach direction, the movement of the first movable core toward the second fixed core relative to the second movable core can be restricted by the limiting part, and the limiting part can be easily provided.

[0023] Furthermore, according to the above structure, the outer cylinder portion of the second movable iron core is located between the inner cylinder portion of the first movable iron core and the filling ring. However, as described above, the radial movement of the first movable iron core relative to the first fixed iron core and the second fixed iron core is restricted. In addition, the filling ring is fixed relative to the first fixed iron core and the second fixed iron core. Therefore, when the first movable iron core moves, there will be no radial displacement of the first movable iron core relative to the filling ring, and the sliding resistance during its movement can be prevented from increasing due to the outer cylinder portion of the second movable iron core being caught between the radially displaced first movable iron core and the filling ring.

[0024] Furthermore, the first movable core of the solenoid may also have a guide portion located on the outer periphery of the front end of the inner cylinder portion protruding outward from the outer cylinder portion, and slidingly contacting the inner periphery of the filling ring. This facilitates limiting the movement of the first movable core relative to the first fixed core and the second fixed core in a direction orthogonal to the coil axis. Furthermore, by axially extending the guide portion, tilting of the first movable core within the filling ring can be suppressed.

[0025] Furthermore, the first movable core of the solenoid may also have a guide portion extending axially from the front end of the inner cylinder portion, which is slidably inserted into a recess formed on the first fixed core. Even in this case, it is easy to limit the movement of the first movable core relative to the first and second fixed cores in a direction orthogonal to the coil axis. In addition, by extending the guide portion axially, tilting of the first movable core within the filling ring can be suppressed.

[0026] Alternatively, the solenoid may include a tube mounted on the first fixed core, which is slidably inserted into the inner side of the inner cylinder. Even in this case, it is easy to limit the movement of the first movable core relative to the first and second fixed cores in a direction orthogonal to the coil axis. Furthermore, by extending the engagement length between the tube and the cylinder, tilting of the first movable core within the filler ring can be suppressed.

[0027] Alternatively, the solenoid may include an annular filling ring installed between the first fixed core and the second fixed core. The first movable core has an inner cylinder and an outer cylinder with two layers arranged in an inner and outer configuration; a connecting portion at one axial end connecting them; and an inner bottom located at the other end of the inner cylinder, with the inner bottom slidably inserted into the inner side of the filling ring facing the second fixed core. The second movable core is a bottomed cylindrical shape, having an outer bottom and an intermediate cylinder with an inner diameter larger than the outer diameter of the inner cylinder. The outer bottom faces the second fixed core, and the intermediate cylinder is slidably inserted into the inner side of the outer cylinder. The spring is installed between the inner bottom and the first fixed core with one end inserted into the inner side of the inner cylinder.

[0028] According to the above structure, when the coil is energized, the magnetic circuit passes through the first fixed iron core, the first movable iron core, the second movable iron core, and the second fixed iron core, thereby attracting the first movable iron core to the first fixed iron core and attracting the second movable iron core to the second fixed iron core. Furthermore, sufficient space for the spring to be accommodated can be ensured inside the first movable iron core.

[0029] Furthermore, according to the above structure, when the first movable core moves toward the second fixed core, the inner bottom of the first movable core approaches the outer bottom of the second movable core. Therefore, if a limiting part is provided to restrict movement in this approach direction, the movement of the first movable core toward the second fixed core relative to the second movable core can be restricted by the limiting part, and the limiting part can be easily provided.

[0030] Furthermore, according to the above structure, since the first movable iron core is slidably inserted into the filling ring, and the second movable iron core is further slidably inserted into the inner side of the first movable iron core, the first movable iron core will not experience radial displacement during movement, and the second movable iron core will not be trapped between the radially displaced first movable iron core and the filling ring. Therefore, there is no need to worry about the second movable iron core being trapped between the radially displaced first movable iron core and the filling ring, thus increasing the sliding resistance during its movement.

[0031] Alternatively, the aforementioned solenoid can be installed in a solenoid valve located midway through the pressure control channel. This solenoid valve, in addition to the solenoid, also has a valve body for opening and closing the pressure control channel. When the solenoid closes the pressure control channel, it applies a force to the valve body that attracts the second movable iron core towards the second fixed iron core, generated when the coil is energized. Thus, the opening pressure of the solenoid valve can be adjusted by changing the amount of current supplied to the solenoid, and the pressure upstream of the solenoid valve can be set as the opening pressure of the solenoid valve.

[0032] Furthermore, as described above, in the solenoid, the greater the current supplied, the greater the thrust applied to the target. Therefore, in the solenoid valve, the greater the current supplied to the solenoid, the greater the thrust applied by the solenoid to the valve body in the closing direction, thereby increasing the opening pressure of the solenoid valve. Additionally, as described above, in the solenoid, even when not energized, the spring can apply force to the target in the same direction as when energized. Therefore, in the solenoid valve, the opening pressure when not energized can be determined based on the spring specifications.

[0033] Alternatively, a solenoid valve including the aforementioned solenoid can be installed in a buffer, the buffer comprising: a cylinder; a rod movably inserted into the cylinder along an axial direction; a main channel for supplying liquid flow when the cylinder and the rod move relative to each other in the axial direction; a main valve body for opening and closing the main channel; a pressure inlet channel having a throttle provided midway to reduce the pressure on the upstream side of the main valve body of the main channel and guide it to the back side of the main valve body; and a pressure control channel connected downstream of the throttle of the pressure inlet channel and provided with the aforementioned solenoid valve.

[0034] Thus, when the cylinder and rod move relative to each other axially, if the main valve body applies resistance to the fluid flow through the main channel, the damper can generate a damping force caused by this resistance. Furthermore, since the back pressure of the main valve body is set to the opening pressure of the solenoid valve, the back pressure of the main valve body can be adjusted by changing the amount of current supplied to the solenoid. Moreover, the higher the back pressure of the main valve body, the more difficult it is to open the main valve body, and the greater the damping force generated. Therefore, according to the above structure, the magnitude of the generated damping force can be adjusted by changing the amount of current supplied to the solenoid.

[0035] Furthermore, as described above, in the solenoid valve, a higher current supplied to the solenoid results in a higher valve opening pressure. Similarly, in the damper, a higher current supplied to the solenoid results in a higher back pressure on the main valve body, leading to a greater damping force. In other words, in the damper, a lower current supplied to the solenoid reduces the damping force, thus reducing power consumption during normal driving when used in a vehicle suspension. Additionally, this suppresses solenoid heating and reduces damper temperature variations, thereby minimizing changes in damping force characteristics (damping force characteristics relative to piston speed) caused by fluid temperature variations.

[0036] Furthermore, as described above, in the solenoid valve, since the valve opening pressure when not energized is determined by the spring specifications, the buffer can increase the back pressure of the main valve body even when the solenoid is not energized. Therefore, the buffer can prevent insufficient damping force in case of malfunction. Moreover, in the buffer, since a pressure control channel is provided as the channel for setting the back pressure of the main valve body, there is no need to switch the channel used for setting the back pressure when the solenoid is energized and de-energized, thus reducing the structural complexity of the buffer and lowering costs.

[0037] Invention Effects

[0038] According to the solenoid, solenoid valve and buffer provided by the present invention, when the current supplied to the solenoid is small, the thrust exerted by the solenoid on the target can be reduced, and even when the solenoid is not energized, it can still exert force on the target in the same direction as the thrust when energized. Attached Figure Description

[0039] Figure 1 This is a longitudinal cross-sectional view of a buffer that includes a solenoid valve comprising a solenoid according to the first embodiment of the present invention.

[0040] Figure 2 This is an enlarged longitudinal cross-sectional view of the solenoid valve including the solenoid according to the first embodiment of the present invention.

[0041] Figure 3 This 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 current supplied to the solenoid in the first embodiment of the present invention and the force acting in the direction of the downward pressing valve body.

[0043] Figure 5 The first modified example of the solenoid according to the first embodiment of the present invention is shown in a partially enlarged cross-sectional view of the solenoid according to the modified example.

[0044] Figure 6 The second modified example of the solenoid according to the first embodiment of the present invention is shown in a partially enlarged cross-sectional view of the solenoid according to the modified example.

[0045] Figure 7 (a) is a partially enlarged cross-sectional view of the solenoid according to the second embodiment of the present invention. Figure 7 (b) is an enlarged view of the Y portion of (a). Detailed Implementation

[0046] Embodiments of the present invention will now be described with reference to the accompanying drawings. In the various drawings, the same reference numerals denote the same components (parts) or corresponding components (parts).

[0047] In various embodiments, a solenoid is used in a solenoid valve, which in turn is used in a damper, and the damper is used in a vehicle suspension. However, the intended use of the solenoid, the solenoid valve with the solenoid, and the damper with the solenoid valve involved in this invention is not limited to this and can be appropriately modified.

[0048] <First Implementation Method>

[0049] like Figure 1 As shown, the buffer D, which includes a solenoid valve V comprising the 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 with one end connected to the piston 10 and the other end protruding outward from 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. In this way, the buffer D is installed between the vehicle body and the axle.

[0050] Furthermore, when the vehicle travels on uneven roads and the wheels vibrate up and down, the piston rod 11 moves in and out of the cylinder 1, the damper D extends and retracts, and the piston 10 moves along the cylinder 1. Figure 1 It moves in the vertical (axial) direction. Additionally, Figure 1 The image shows the piston rod 11 protruding upwards from the cylinder 1, but the buffer D can also be installed on the vehicle in any orientation.

[0051] Next, at one axial end of the cylinder 1, an annular head member 12 is installed, the inner side of which allows the piston rod 11 to pass through. This head member 12 slidably supports the piston rod 11 and seals one end of the cylinder 1. On the other hand, the other end of the cylinder 1 is blocked by a bottom cover 13. In this way, the cylinder 1 is sealed, and liquid and gas are confined within the cylinder 1.

[0052] More specifically, when viewed from the piston 10 side, the free piston 14 is slidably inserted into the cylinder 1 on the side opposite to the piston rod 11. Furthermore, within the cylinder 1, 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. On the other hand, within the cylinder 1, when viewed from the free piston 14 side, a gas chamber G for sealing compressed gas is formed on the side opposite to the piston 10.

[0053] In this way, the liquid chamber L and the gas chamber G within cylinder 1 are separated by the free piston 14. Furthermore, when the buffer D extends or retracts, and the piston rod 11 moves in and out of cylinder 1, the free piston 14 remains within cylinder 1... Figure 1 The gas chamber G expands or contracts as it moves up and down (axially) to compensate for the volume of the piston rod 11 entering and exiting the cylinder 1.

[0054] In addition to the free piston 14, the liquid chamber L and the gas chamber G can also be separated by an air bladder or bellows. That is, the structure forming the movable partition of the expandable and contractible gas chamber G is not limited to the free piston 14 and can be modified appropriately. Furthermore, the structure used to compensate for the volume of the piston rod 11 entering and exiting the cylinder 1 is not limited to the gas chamber G and can also be modified appropriately. For example, a reservoir containing both liquid and gas can be provided instead of the gas chamber G, and liquid can be exchanged between the cylinder and the reservoir when the buffer extends or retracts. Furthermore, the buffer D can be a double-rod type, with piston rods provided on both sides of the piston; in this case, the structure itself used to compensate for the volume of the piston rods can be omitted.

[0055] Next, the liquid chamber L inside cylinder 1 is divided by piston 10 into an elongation-side chamber L1 on the piston rod 11 side and a compression-side chamber L2 on the opposite side (opposite to the piston rod). Figure 2 As shown, the piston 10 is a bottomed cylindrical shape, including: a cylindrical portion 10b with piston rings 10a mounted on its outer periphery that slide in contact with the inner periphery of the cylinder 1; and a bottom 10c that blocks one end of the cylindrical portion 10b. Hereinafter, for ease of description, unless otherwise stated, all other descriptions will be... Figure 2 The vertical direction in the text is simply referred to as "up" and "down".

[0056] Therefore, the piston 10 is positioned with its bottom 10c facing downwards and its cylindrical portion 10b facing upwards. The cylindrical portion 10b is connected to the top cylindrical housing portion 11a formed at the front end of the piston rod 11 via a cylindrical guide 15. Furthermore, an annular valve seat component 16 is fixed between the lower end of the guide 15 and the piston 10. Moreover, a main valve body 2, which sits on or moves off the valve seat component 16, is provided inside the guide 15.

[0057] 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 piston 10 separates the intermediate chamber L3 from the compression side chamber L2. Furthermore, ports 10d and 10e are formed at the bottom 10c of the piston 10, connecting the intermediate chamber L3 to the extension side and the compression side of the compression side chamber L2. Moreover, an extension side valve 20 is stacked on the lower side of the bottom 10c, which opens and closes the outlet of the extension side port 10d, and 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.

[0058] Furthermore, the inlet of the elongated side port 10d opens into the intermediate chamber L3, and the pressure in the intermediate chamber L3 acts in the direction of opening the elongated side valve 20. Moreover, under the pressure of the intermediate chamber L3, after the elongated side valve 20 opens, the liquid in the intermediate chamber L3 flows through the elongated side port 10d to the compression side chamber L2. On the other hand, the inlet of the compression side port 10e opens into the compression side chamber L2, and the pressure in the compression side chamber L2 acts in the direction of opening the compression side valve 21. Moreover, under the pressure of the compression side chamber L2, after the compression side valve 21 opens, the liquid in the compression side chamber L2 flows through the compression side port 10e to the intermediate chamber L3.

[0059] Next, as described above, the main valve body 2 has 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 can be freely inserted into the inner side of the valve seat component 16 along the axial direction, and can be seated or detached from the valve seat component 16. On the other hand, the second valve body portion 2B includes a head 2a and a flange portion 2b extending outward from the lower end of the head 2a. Moreover, the head 2a and the flange portion 2b of the second valve body portion 2B respectively slide in contact with the inner periphery of the guide member 15, and the lower end of the second valve body portion 2B can be seated or detached from the first valve body portion 2A.

[0060] Furthermore, the guide member 15 has a through hole 15a opening into the elongated side chamber L1. The pressure in the elongated side chamber L1 acts on both the first valve body 2A and the second valve body 2B, causing the first valve body 2A to disengage from the valve seat member 16. Moreover, when the first valve body 2A and the second valve body 2B move upward together and disengage from the valve seat member 16 under the pressure of the elongated side chamber L1, the liquid in the elongated side chamber L1 flows to the intermediate chamber L3 through the gap formed between the first valve body 2A and the valve seat member 16.

[0061] The intermediate chamber L3 is located on the inner circumference of the valve seat component 16, the first valve body portion 2A, and the cylindrical portion 10b of the piston 10, and is formed between the bottom 10c of the piston 10 and the second valve body portion 2B. The pressure of the intermediate chamber L3 acts in the direction of pressing down the first valve body portion 2A and pushing up the second valve body portion 2B. That is, the pressure of the intermediate chamber L3 acts in the direction of separating the first valve body portion 2A and the second valve body portion 2B vertically and causing the second valve body portion 2B to leave the seat of the first valve body portion 2A. Moreover, under the pressure of the intermediate chamber L3, after the second valve body portion 2b moves upward and leaves the seat of the first valve body portion 2A, the liquid in the intermediate chamber L3 flows to the elongated side chamber L1 through the gap and through hole 15a formed between the first valve body portion 2A and the second valve body portion 2B.

[0062] In summary, in this embodiment, a main channel M is formed by the through hole 15a of the guide member 15, the intermediate chamber L3, and the ports 10d and 10e on the elongation side and the compression side, connecting the elongation side chamber L1 and the compression side chamber L2. Furthermore, a main valve body 2 is provided in this main channel M, and an elongation side valve 20 and a compression side valve 21 are connected in series with the main valve body 2.

[0063] 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 the back pressure chamber L4 acts in the direction that pushes the second valve body portion 2B and the first valve body portion 2A down together. Furthermore, the second valve body portion 2B includes: a pressure inlet channel p1, which has a throttle O installed in the middle to reduce the pressure in the extended side chamber L1 and introduce it into the back pressure chamber L4; a pressure control channel p2, which is connected downstream of the throttle O in the pressure inlet channel p1; and a pressure reduction channel p3, which only allows liquid to flow from the intermediate chamber L3 to the back pressure chamber L4 and reduces the pressure in the intermediate chamber L3 before introducing it into the back pressure chamber L4.

[0064] Furthermore, a solenoid valve V, including the solenoid S1 described in this embodiment, is provided midway through the aforementioned pressure control channel p2. This solenoid valve V is configured to include: a valve core 3, which, as a valve seat 22 provided on the second valve body 2B, opens and closes the pressure control channel p2; and a solenoid S1, which applies a downward thrust to the valve core 3. Moreover, when the valve core 3 moves downward under the thrust of the solenoid S1, it sits on the valve seat 22, thereby closing the pressure control channel p2. Thus, the thrust of the solenoid S1 acts in the direction of closing the valve core 3.

[0065] On the other hand, the pressure in the back pressure chamber L4 acts in the direction of pushing the valve core 3 upward. Furthermore, as the pressure in the back pressure chamber L4 increases, the upward force caused by this pressure overcomes the downward force caused by the solenoid S1, causing the valve core 3 to move upward, disengage from the valve seat 22, and open the pressure control channel p2. In other words, when the pressure in the back pressure chamber L4 acts in the direction of opening the valve core 3, and the pressure in the back pressure chamber L4 reaches the valve core 3's opening pressure, the valve core 3 opens the pressure control channel p2. Thus, the action of the valve core 3 sitting or disengaging from the valve seat 22 to open and close the pressure control channel p2 is also referred to as the opening and closing of the solenoid valve V.

[0066] Furthermore, in this embodiment, when the solenoid valve V is opened, the liquid in the back pressure chamber L4 flows out through the pressure control channel p2 to the upper gap L5 formed between the head 2a of the second valve body 2B and the solenoid S1. This upper gap L5 is connected to the intermediate chamber L3 through the connecting channel p4 formed in the second valve body 2B. Thus, when the solenoid valve V is opened, the liquid flows from the back pressure chamber L4 to the upper gap L5 through the pressure control channel p2, and from the upper gap L5 to the intermediate chamber L3 through the connecting channel p4. Furthermore, due to the connecting channel p4, the pressure in the upper gap L5 and the intermediate chamber L3 is approximately the same.

[0067] Next, the solenoid S1 according to this embodiment includes: a coil 4, which is axially housed in the housing portion 11a of the piston rod 11; a first fixed iron core 5, which is disposed on the upper side of the coil 4; a second fixed iron core 6, which is disposed on the lower side of the coil 4 with a gap between it and the first fixed iron core 5; a first movable iron core 7 and a second movable iron core 8, which are movably disposed between the first fixed iron core 5 and the second fixed iron core 6; a spring 9, which applies a downward force to the first movable iron core 7; a leaf spring 90, which limits the downward movement of the first movable iron core 7 relative to the second movable iron core 8; and a leaf spring 91, which limits the downward movement of the second movable iron core 8.

[0068] Here, the direction along the centerline X passing through the center of coil 4 is the axial direction of coil 4, and "up" and "down" refer to the two sides of the axial direction of coil 4. Therefore, it can be said that the first fixed iron core 5 is disposed on one end side of the axial direction of coil 4, and the second fixed iron core 6 is disposed on the other end side of the axial direction of coil 4. Furthermore, it can be said that the spring 9 applies a force to the first movable iron core 7 towards the second fixed iron core 6, the leaf spring 90 functions as a limiting part to restrict the movement of the first movable iron core 7 relative to the second movable iron core 8 towards the second fixed iron core 6, and the leaf spring 91 functions as a limiting part to restrict the movement of the second movable iron core 8 towards the second fixed iron core 6.

[0069] The following describes in detail the various parts constituting the solenoid S1 according to this embodiment.

[0070] The coil 4 is integrally formed with the energizing wire harness 40 through molding resin. The wire harness 40 extends from the inside of the piston rod 11 to the outside of the buffer D and is connected to the power source. In addition, the first fixed iron core 5, the second fixed iron core 6, the first movable iron core 7, and the second movable iron core 8 are each made of magnetic material. When the coil 4 is energized, a magnetic flux is generated. This magnetic flux flows in the path of the first fixed iron core 5, the first movable iron core 7, the second movable iron core 8, the second fixed iron core 6, and the housing portion 11a. The first movable iron core 7 is attracted upward toward the first fixed iron core 5, and the second movable iron core 8 is attracted downward toward the second fixed iron core 6.

[0071] An annular filling ring 41 made of non-magnetic material is installed between the first fixed iron core 5 and the second fixed iron core 6, creating a magnetic gap between them. Furthermore, a first movable iron core 7 and a second movable iron core 8 are disposed inside the filling ring 41. Both the first movable iron core 7 and the second movable iron core 8 are bottomed cylindrical shapes. The first movable iron core 7 can be inserted vertically (axially) into the inside of the second movable iron core 8, and the second movable iron core 8 can be inserted vertically (axially) into the inside of the filling ring 41.

[0072] like Figure 3 As shown, the outer cylinder, i.e., the second movable iron core 8, has an outer bottom 8a and an outer cylinder portion 8b standing on the outer periphery of the outer bottom 8a. The outer bottom 8a faces downward (towards the second fixed iron core 6), and the outer cylinder portion 8b slides in contact with the inner periphery of the filling ring 41. On the other hand, the first movable iron core 7, which is the inner cylinder, has an inner bottom 7a, an inner cylinder portion 7b standing on the outer periphery of the inner bottom 7a, and an annular guide portion 7c located on the outer periphery of the front end of the inner cylinder portion 7b. The inner cylinder portion 7b is inserted into the outer cylinder portion 8b with the inner bottom 7a facing downward (towards the second fixed iron core 6), and the guide portion 7c protruding upward from the outer cylinder portion 8b slides in contact with the inner periphery of the filling ring 41.

[0073] A through-hole 7d, extending through its thickness, is formed on the inner bottom 7a of the first movable iron core 7, allowing liquid to move relatively unimpeded within it. Therefore, liquid is not trapped in the upper part of the first movable iron core 7 (the side of the first fixed iron core 5), ensuring smooth vertical movement of the first movable iron core 7. A spring 9 is inserted inside the inner cylinder portion 7b of the first movable iron core 7. In this embodiment, the spring 9 is a helical spring, with one end abutting against the inner bottom 7a. The other end of the spring 9 is supported by the first fixed iron core 5, and the spring 9 exerts a downward force on the first movable iron core 7.

[0074] Furthermore, the inner diameter of the outer cylinder portion 8b of the second movable iron core 8 is larger than the outer diameter of the inner cylinder portion 7b of the first movable iron core 7, forming an annular gap between the outer cylinder portion 8b and the inner cylinder portion 7b, allowing the liquid to move relatively unimpeded within this gap. Additionally, a through-hole 8c, extending through its thickness, is formed on the outer bottom 8a of the second movable iron core 8, allowing the liquid to move relatively unimpeded within this through-hole 8c. Therefore, it is possible to prevent the liquid from being trapped in the space L6 formed on the upper front end (first fixed iron core 5 side) of the outer cylinder portion 8b or the space L7 formed on the upper side (first fixed iron core 5 side) of the outer bottom 8a, thus preventing the generation of a damping force that hinders the movement of the second movable iron core 8.

[0075] Furthermore, in this embodiment, since the guide portion 7c is supported by the filling ring 41 while the first movable iron core 7 moves up and down (axially), it will not become eccentric relative to the filling ring 41 during its movement. Because the filling ring 41 is clamped between the first fixed iron core 5 and the second fixed iron core 6 and is fixed relative to both, it can prevent the first movable iron core 7 from shifting radially in a direction orthogonal to the center line X of the coil 4 due to the filling ring 41. Therefore, it can prevent the first movable iron core 7 from radially shifting during its movement, thus preventing the outer cylinder portion 8b of the second movable iron core 8 from being clamped between the first movable iron core 7 and the filling ring 41, increasing friction during the movement of the second movable iron core 8. This ensures smooth up and down movement of the second movable iron core 8.

[0076] Next, leaf springs 90 and 91, which function as limiting parts as described above, are arranged above and below the outer bottom 8a of the second movable iron core 8. More specifically, the first limiting part, namely the upper leaf spring 90, is located between the outer bottom 8a of the second movable iron core 8 and the inner bottom 7a of the first movable iron core 7, which is vertically opposite to it, and the second limiting part, namely the lower leaf spring 91, is located between the outer bottom 8a of the second movable iron core 8 and the second fixed iron core 6, which is vertically opposite to it.

[0077] Furthermore, the upper leaf spring 90 includes an annular seat portion stacked on the outer bottom 8a of the second movable iron core 8, and a plurality of support portions extending radially outward from the seat portion and tilting upward. On the other hand, the lower leaf spring 91 includes an annular seat portion stacked on the second fixed iron core 6, and a plurality of support portions extending inward from the seat portion and tilting upward. Therefore, the upper and lower leaf springs 90 and 91 each include a plurality of support portions, and gaps are formed between adjacent support portions, so the leaf springs 90 and 91 do not obstruct the flow of liquid.

[0078] Furthermore, when the first movable core 7 moves downward relative to the second movable core 8, its inner bottom 7a abuts against the leaf spring 90. This restricts the downward movement of the first movable core 7 relative to the second movable core 8, and subsequently, the first movable core 7 and the second movable core 8 move downward as a single unit. Additionally, when the second movable core 8 moves downward, its outer bottom 8a abuts against the leaf spring 91, compressing it and preventing further downward movement.

[0079] A through hole is formed in the center of the second fixed iron core 6, through which the shaft portion 3a of the valve core 3 can be freely inserted. Furthermore, the front end of the shaft portion 3a abuts against the outer bottom 8a of the second movable iron core 8. Therefore, when the energization of the coil 4 is disconnected, the first movable iron core 7 moves downward under the force of the spring 9 and abuts against the second movable iron core 8 via the leaf spring 90. Thus, the valve core 3 experiences a downward force due to the force of the spring 9. Conversely, when the coil 4 is energized, attracting the first movable iron core 7 to the first fixed iron core 5 and the second movable iron core 8 to the second fixed iron core 6, although the spring 9 is compressed by the first movable iron core 7 and its force is not transmitted to the valve core 3, the valve core 3 still experiences a downward force due to the force attracting the second movable iron core 8.

[0080] Furthermore, the first limiting part, namely the leaf spring 90, restricts the approach between the inner bottom 7a of the first movable iron core 7 and the outer bottom 8a of the second movable iron core 8, which is vertically (axially) opposite to it, preventing the first movable iron core 7 and the second movable iron core 8 from being attracted to each other when the coil 4 is energized. Similarly, the second limiting part, namely the leaf spring 91, restricts the approach between the outer bottom 8a of the second movable iron core 8 and the second fixed iron core 6, which is vertically (axially) opposite to it, preventing the second movable iron core 8 from being attracted to the second fixed iron core 6 when the coil 4 is energized.

[0081] Furthermore, the first and second limiting parts are not limited to leaf springs 90 and 91, but can also be rings or plates made of non-magnetic materials such as rubber, synthetic resin, or aluminum. In this case, the ring or plate can be disposed on the outer periphery of the inlet or outlet of the connecting holes 7d and 8c to avoid obstructing the flow of liquid. Moreover, as long as they do not obstruct the movement of the first movable iron core 7 relative to the second movable iron core 8 and the movement of the second movable iron core 8 relative to the second fixed iron core 6 when energized, the first and second limiting parts can also be magnetic materials. Alternatively, a part of the first movable iron core 7 or the second movable iron core 8 can function as the first limiting part, or a part of the second movable iron core 8 or the second fixed iron core 6 can function as the second limiting part.

[0082] On the other hand, no limiting part is provided between the first fixed iron core 5 and the first movable iron core 7. When the coil 4 is energized, the first movable iron core 7 is attracted to the first fixed iron core 5. In this way, if the first movable iron core 7 is attracted to the first fixed iron core 5 when the coil 4 is energized, the posture of the first movable iron core 7 can be stably maintained. In this posture, the first movable iron core 7 compresses the spring 9, and the force of the spring 9 is not transmitted to the second movable iron core 8. However, it is not necessary for the first movable iron core 7 to be attracted to the first fixed iron core 5 when the coil 4 is energized.

[0083] then, Figure 4 The relationship between the current supplied to solenoid S1 and the force exerted by solenoid S1 on valve core 3 is shown. Figure 4 In this context, Ia is the minimum current required to attract the first movable iron core 7, which is in a state far from the first fixed iron core 5, to the first fixed iron core 5. Ib is the minimum current required to maintain the attraction between the first fixed iron core 5 and the first movable iron core 7 after the first movable iron core 7 is attracted to the first fixed iron core 5. Ic will be described below.

[0084] First, when the current supplied to coil 4 is zero, that is, when solenoid S1 is not energized, the first movable iron core 7 is pressed down by the force of spring 9, and abuts against the second movable iron core 8 through leaf spring 90, and the second movable iron core 8 is pressed down together with the valve core 3. Thus, when solenoid S1 is not energized, the valve core 3 is subjected to a downward force generated by spring 9 through the second movable iron core 8, leaf spring 90, and first movable iron core 7. In other words, when solenoid S1 is not energized, solenoid S1 applies a downward force to valve core 3 generated by the force of spring 9.

[0085] Next, as the current supplied to the solenoid S1 increases, the upward force attracting the first movable iron core 7 to the first fixed iron core 5 increases, and the downward force attracting the second movable iron core 8 to the second fixed iron core 6 also increases. In this case, in the region where the current supplied to the solenoid S1 is less than Ia, although the force of the spring 9 is transmitted to the valve core 3, part of the force of the spring 9 that applies downward force to the first movable iron core 7 is offset by the force that attracts the first movable iron core 7 upward (to the side of the first fixed iron core 5). Therefore, in the region where the current is less than Ia, the greater the current supplied to the solenoid S1, the smaller the downward force exerted by the solenoid S1 on the valve core 3.

[0086] On the other hand, when the current supplied to the solenoid S1 increases, in the region where the current is Ia or higher, the first movable iron core 7 resists the force of the spring 9 and is attracted and attracted to the first fixed iron core 5. In this state, the force of the spring 9 is not transmitted to the second movable iron core 8; only the force that attracts the second movable iron core 8 to the second fixed iron core 6 acts in the direction of pressing down the valve core 3. The downward force attracting the second movable iron core 8 increases proportionally to the current supplied to the solenoid S1. Therefore, in the region where the current supplied to the solenoid S1 is Ia or higher, the greater the current supplied to the solenoid S1, the more proportionally the downward force exerted by the solenoid S1 on the valve core 3 increases.

[0087] Conversely, when the first movable iron core 7 is adsorbed onto the first fixed iron core 5 and the force of the spring 9 is not transmitted to the second movable iron core 8, reducing the current supplied to the solenoid S1 decreases the upward force attracting the first movable iron core 7 to the first fixed iron core 5, and also reduces the downward force attracting the second movable iron core 8 to the second fixed iron core 6. Even in this case, in the region where the current supplied to the solenoid S1 is Ib or more, the first movable iron core 7 remains adsorbed onto the first fixed iron core 5, and the force of the spring 9 is not transmitted to the second movable iron core 8. Therefore, in the region where the current supplied to the solenoid S1 is Ib or more, the less current supplied to the solenoid S1, the more proportionally the downward force exerted by the solenoid S1 on the valve core 3 decreases.

[0088] On the other hand, when the first movable iron core 7 is attracted to the first fixed iron core 5 and the force of the spring 9 is not transmitted to the second movable iron core 8, if the current supplied to the solenoid S1 is reduced and the current is less than Ib, the attraction between the first movable iron core 7 and the first fixed iron core 5 will be released due to the force of the spring 9, and the force of the spring 9 will be transmitted to the second movable iron core 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 core 3.

[0089] from Figure 4 It can also be seen that the minimum current required to maintain the adsorption between the first movable iron core 7 and the first fixed iron core 5, i.e., Ib, is less than the minimum current required to adsorb the first movable iron core 7, which is in a separated state, onto the first fixed iron core 5, i.e., Ia (Ia>Ib). Therefore, the force exerted by the solenoid S1 on the valve core 3 has a hysteresis characteristic relative to the current supplied to the solenoid S1. In addition, in Figure 4 In the diagram, for ease of understanding, the region where the current supplied to solenoid S1 is relatively small is shown in magnified form.

[0090] Furthermore, in this embodiment, when it is desired to control the amount of current supplied to the solenoid S1 to control the force exerted by the solenoid S1 on the valve core 3, a current of Ia or higher is first supplied to attract the first movable iron core 7 to the first fixed iron core 5. Then, the amount of current supplied to the solenoid S1 is controlled within a range greater than Ib and greater than Ic. Thus, when the current supplied to the solenoid S1 is controlled to be normal, the state in which the first movable iron core 7 is attracted to the first fixed iron core 5 is maintained. Therefore, the amount of current supplied to the solenoid S1 is proportional to the downward force exerted by the solenoid S1 on the valve core 3; the greater the amount of current supplied to the solenoid S1, the greater the force.

[0091] During normal operation (control mode), the force exerted by solenoid S1 on valve core 3 due to the magnetic force generated by energizing solenoid S1 is called the "thrust" of solenoid S1. In other words, the thrust of solenoid S1 can be controlled by controlling the amount of current supplied to it. Furthermore, in this embodiment, the amount of current supplied to solenoid S1 is proportional to the thrust exerted by solenoid S1 on valve core 3; a larger supply current results in a larger thrust, and a smaller supply current results in a smaller thrust.

[0092] On the other hand, when a power failure occurs in solenoid S1, the valve core 3 is subjected to a downward force by the spring 9 of solenoid S1. This force can be predetermined according to the specifications of spring 9, such as the spring constant. Furthermore, the direction of the force exerted on the valve core 3 by spring 9 during a fault (when no power is supplied) is the same as the direction of the thrust applied to the valve core 3 during normal operation.

[0093] The operation of the buffer D, which includes the solenoid valve V comprising the solenoid S1 according to this embodiment, will be described below.

[0094] When the buffer D extends, the piston 10 moves upward within the cylinder 1, compressing the extension chamber L1. As the pressure in the extension chamber L1 rises, the liquid in the extension chamber L1 flows into the back pressure chamber L4 through the pressure inlet channel p1, causing the pressure in the back pressure chamber L4 to rise. Then, when the pressure in the back pressure chamber L4 reaches the opening pressure of the valve core 3, the valve core 3 (solenoid valve V) opens, and the liquid in the back pressure chamber L4 flows to the intermediate chamber L3 through the pressure control channel p2, the upper clearance L5, and the connecting channel p4. Therefore, when the buffer D extends, the pressure in the back pressure chamber L4 is controlled to be the opening pressure of the solenoid valve V.

[0095] Furthermore, when the buffer D extends, the upward force caused by the pressure in the extended side chamber L1 of the first valve body 2A and the second valve body 2B exceeds the downward force caused by the pressure in the back pressure chamber L4, causing the first valve body 2A and the second valve body 2B to move upward. As a result, a gap is formed between the first valve body 2A and the valve seat component 16, through which the liquid in the extended side chamber L1 moves towards the intermediate chamber L3, and the liquid in the intermediate chamber L3 opens the extended side valve 20 and moves towards the compression side chamber L2.

[0096] Thus, when the buffer D extends, the first valve body portion 2A in the main valve body 2 and the extension-side valve 20 open, applying resistance to the liquid flowing from the extension-side chamber L1 to the compression-side chamber L2 in the main channel M through the main valve body 2 and the extension-side valve 20. Therefore, when the buffer D extends, the pressure in the extension-side chamber L1 rises, and the buffer D generates a damping force on the extension side that hinders its extension action.

[0097] Furthermore, under normal conditions of controlling the current supplied to solenoid S1, the greater the current supplied to solenoid S1, the greater the downward (closing direction) thrust exerted by solenoid S1 on valve core 3. Therefore, the greater the current supplied to solenoid S1, the higher the opening pressure of valve core 3 (solenoid valve V), and consequently the higher the pressure in back pressure chamber L4.

[0098] Furthermore, the pressure in the back pressure chamber L4 applies downward (closing direction) pressure to the second valve body 2B and the first valve body 2A. Therefore, the greater the current supplied to the solenoid S1 and the higher the pressure in the back pressure chamber L4, the higher the opening pressure of the first valve body 2A in the main valve body 2, resulting in a greater damping force on the extension side. Thus, under normal conditions, the damping force on the extension side can be adjusted by using the solenoid S1 to adjust the opening pressure of the valve core 3. Additionally, in Figure 2 , 3 The image shows the state of valve core 3 when it is normally open.

[0099] On the other hand, when a power failure occurs in solenoid S1, the opening pressure of valve core 3 (solenoid valve V) is determined by the force of spring 9. Therefore, during a failure, the pressure in back pressure chamber L4 is determined by the specifications of spring 9, and thus determines the damping force on the extension side. As described above, since the force of spring 9 is not transmitted to valve core 3 under normal conditions, the damping force on the extension side under normal conditions can be disregarded, and the specifications of spring 9 can be freely set.

[0100] Conversely, when the buffer D contracts, the piston 10 moves downward within the cylinder 1, compressing the compression chamber L2. As the pressure in the compression chamber L2 rises, the liquid in the compression chamber L2 opens the compression valve 21 and moves towards the intermediate chamber L3. The liquid in the intermediate chamber L3 then moves towards the back pressure chamber L4 through the pressure-reducing channel p3. At this time, the pressure in the upper clearance L5 downstream of the valve core 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 core 3. Therefore, the valve core 3 is kept closed. Furthermore, in this state, the thrust of the solenoid S1 is applied downward to the second valve body 2B via the valve core 3.

[0101] Furthermore, as described above, since the pressure in the intermediate chamber L3 is applied upward only to the second valve body 2B, when the upward force generated by the pressure of the intermediate chamber L3 acting on the second valve body 2B exceeds the downward force generated by the thrust of the solenoid S1, only the second valve body 2B moves upward. Thus, a gap is formed between the second valve body 2B and the first valve body 2A, and the liquid in the intermediate chamber L3 moves through this gap to the elongated side chamber L1.

[0102] Thus, when the buffer D contracts, the compression-side valve 21 and the second valve body portion 2B in the main valve body 2 open, applying resistance to the liquid flowing from the compression-side chamber L2 to the extension-side chamber L1 in the main channel M through the compression-side valve 21 and the main valve body 2. Therefore, when the buffer D contracts, the pressure in the compression-side chamber L2 increases, and the buffer D generates a damping force on the compression side that hinders its contraction action.

[0103] Furthermore, under normal conditions where the current supplied to solenoid S1 is controlled, the greater the current supplied to solenoid S1 and the greater the thrust of solenoid S1, the greater the downward (closing direction) force acting on the second valve body 2B. Therefore, the greater the current supplied to solenoid S1 and the greater the thrust of solenoid S1, the higher the valve opening pressure of the second valve body 2B in the main valve body 2, and the greater the damping force on the compression side. Thus, under normal conditions, the magnitude of the damping force on the compression side is adjusted by using solenoid S1 to regulate the downward pressing force of the second valve body 2B via the valve core 3.

[0104] On the other hand, when a power failure occurs in the solenoid S1, 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 failure is also determined according to the specifications of the spring 9. As described above, since the force of the spring 9 is not transmitted to the valve core 3 under normal conditions, the damping force on the compression side under normal conditions can be disregarded, and the specifications of the spring 9 can be freely set.

[0105] The effects of the solenoid S1, the solenoid valve V including the solenoid S1, and the buffer D including the solenoid valve V according to this embodiment will be explained below.

[0106] The solenoid S1 according to this embodiment includes: a coil 4; a first fixed iron core 5 located at one end of the axial direction of the coil 4; a second fixed iron core 6 located at the other end of the axial direction of the coil 4 and having a gap with the first fixed iron core 5; a first movable iron core 7 disposed between the first fixed iron core 5 and the second fixed iron core 6, which is attracted by the first fixed iron core 5 when the coil 4 is energized; a second movable iron core 8 disposed between the first fixed iron core 5 and the second fixed iron core 6, which is attracted by the second fixed iron core 6 when the coil 4 is energized; a spring 9 that applies force to the first movable iron core 7 toward the second fixed iron core 6; and a leaf spring (limiting part) 90 that limits the movement of the first movable iron core 7 relative to the second movable iron core 8 toward the second fixed iron core 6. Furthermore, the movement of the first movable iron core 7 relative to the first fixed iron core 5 and the second fixed iron core 6 in a direction orthogonal to the axial direction of the coil 4 is limited.

[0107] According to the above configuration, when the solenoid S1 is not energized, the first movable iron core 7 moves towards the second fixed iron core 6 under the force of the spring 9. When the movement of the first movable iron core 7 relative to the second movable iron core 8 towards the second fixed iron core 6 is restricted by the leaf spring 90, the first movable iron core 7 and the second movable iron core 8 become one unit and move towards the second fixed iron core 6. Therefore, when the solenoid S1 is not energized, the force of the spring 9 is transmitted to the second movable iron core 8 through the first movable iron core 7 and the leaf spring 90.

[0108] On the other hand, when solenoid S1 is energized, if the first movable iron core 7 is attracted by the first fixed iron core 5 and moves in the direction of attraction, then spring 9 is compressed by the first movable iron core 7, and the force of spring 9 is not transmitted to the second movable iron core 8. Furthermore, when solenoid S1 is energized, the second movable iron core 8 is attracted by the second fixed iron core 6, and the greater the current supplied to solenoid S1, the greater the force attracting the second movable iron core 8 to the second fixed iron core 6.

[0109] Therefore, if the force attracting the second movable iron core 8 is applied as a thrust to the target object such as the valve core 3 when the solenoid S1 is energized, the greater the current supplied to the solenoid S1, the greater the thrust applied to the target object; conversely, the smaller the current supplied to the solenoid S1, the smaller the thrust applied to the target object. Furthermore, when not energized, the force of the spring 9 acts on the target object via the first movable iron core 7, the leaf spring (restriction part) 90, and the second movable iron core 8. Since the direction of the force of the spring 9 is the same as the direction of the force attracting the second movable iron core 8 when the solenoid S1 is energized, according to the above structure, even when the solenoid S1 is not energized, a force can be applied to the target object in the same direction as when it is energized.

[0110] Furthermore, according to the above structure, as described above, when the solenoid S1 is energized, if the first movable iron core 7 moves towards the first fixed iron core 5 against the force of the spring 9, the force exerted by the spring 9 is not transmitted to the second movable iron core 8, and therefore not to the valve core (target) 3. Thus, the thrust of the solenoid S1 when energized and the force exerted on the target by the spring 9 when not energized can be freely set separately. Additionally, although the spring 9 is a helical spring in this embodiment, it can also be a spring other than a helical spring, such as a disc spring.

[0111] Furthermore, in this embodiment, the movement of the first movable core 7 of the solenoid S1 relative to the first fixed core 5 and the second fixed core 6 in a direction orthogonal to the axial direction of the coil 4 (along the direction of the center line X of the coil 4) is restricted. In other words, the first movable core 7 will not move radially toward the coil 4 relative to the first fixed core 5 and the second fixed core 6. As a result, the movement of the second movable core 8 is not hindered by the radially offset first movable core 7, ensuring smooth up-and-down movement of the second movable core 8. Consequently, as described above, when the force attracting the second movable core 8 is applied as a thrust to the target object, it is possible to suppress the hysteresis of the thrust relative to the current supplied to the solenoid S1, and the thrust can be easily controlled.

[0112] Furthermore, the solenoid S1 according to this embodiment includes an annular filling ring 41, which is installed between the first fixed iron core 5 and the second fixed iron core 6. The second movable iron core 8 is a bottomed cylindrical shape, having an outer bottom 8a and an outer cylindrical portion 8b standing upright on the outer periphery of the outer bottom 8a. The outer bottom 8a is axially movably inserted into the inner side of the filling ring 41, facing the second fixed iron core 6. The first movable iron core 7 is also a bottomed cylindrical shape, having an inner bottom 7a and an inner cylindrical portion 7b standing upright on the outer periphery of the inner bottom 7a with an outer diameter smaller than the inner diameter of the outer cylindrical portion 8b. The inner bottom 7a is axially movably inserted into the inner side of the outer cylindrical portion 8b of the second movable iron core 8, facing the second fixed iron core 6. Furthermore, a spring 9 is installed between the inner bottom 7a and the first fixed iron core 5, with one end inserted into the inner side of the inner cylindrical portion 7b of the first movable iron core 7.

[0113] According to the above structure, when the coil 4 is energized, the magnetic circuit passes through the first fixed iron core 5, the first movable iron core 7, the second movable iron core 8, and the second fixed iron core 6, thereby attracting the first movable iron core 7 to the first fixed iron core 5 and attracting the second movable iron core 8 to the second fixed iron core 6. Furthermore, while ensuring the accommodation space for the spring 9 inside the first movable iron core 7, the first movable iron core 7 and the second movable iron core 8 can be miniaturized, thus enabling the solenoid S1 to be miniaturized.

[0114] Furthermore, according to the above configuration, when the first movable core 7 moves towards the second fixed core 6, the inner bottom 7a of the first movable core 7 approaches the outer bottom 8a of the second movable core 8. Therefore, if the leaf spring (restricting part) 90 is configured to restrict their movement in the approach direction, the movement of the first movable core 7 relative to the second movable core 8 towards the second fixed core 6 can be restricted. Moreover, to configure the leaf spring 90 in this way, for example, it is easy to configure the leaf spring 90 between the inner bottom 7a and the outer bottom 8a as in this embodiment. In other words, according to the above structure, the leaf spring (restricting part) 90 can be easily configured.

[0115] Furthermore, in the solenoid S1 described above, the outer cylinder portion 8b of the second movable iron core 8 is located between the inner cylinder portion 7b of the first movable iron core 7 and the filling ring 41. However, as described above, the radial (orthogonal to the axial direction of the coil 4) movement of the first movable iron core 7 relative to the first fixed iron core 5 and the second fixed iron core 6 is restricted. Additionally, the filling ring 41 is installed between the first fixed iron core 5 and the second fixed iron core 6 and is fixed relative to them. Therefore, according to the solenoid S1 described above, when the first movable iron core 7 is attracted to the first fixed iron core 5, it will not undergo radial displacement relative to the filling ring 41. Therefore, according to the solenoid S1 described above, it is possible to prevent the outer cylinder portion 8b of the second movable iron core 8 from being trapped between the first movable iron core 7 and the filling ring 41, which would increase the sliding resistance during movement and hinder the smooth up-and-down movement of the second movable iron core 8.

[0116] Furthermore, the first movable iron core 7 of the solenoid S1 according to this embodiment has a guide portion 7c, which is located on the outer periphery of the front end of the inner cylinder portion 7b that protrudes outward from the outer cylinder portion 8b of the second movable iron core 8, and slides in contact with the inner periphery of the filling ring 41. In this case, the sliding gap formed between the filling ring 41 and the guide portion 7c is very small, even smaller than the gap formed between the outer cylinder portion 8b and the inner cylinder portion 7b. In other words, the difference between the inner diameter of the filling ring 41 and the outer diameter of the guide portion 7c is smaller than the difference between the inner diameter of the outer cylinder portion 8b and the outer diameter of the inner cylinder portion 7b.

[0117] According to the above structure, by using the filling ring 41 to support the guide portion 7c of the first movable iron core 7, it is possible to prevent the first movable iron core 7 from shifting radially (in a direction orthogonal to the axial direction of the coil 4) relative to the first fixed iron core 5 and the second fixed iron core 6, and to simplify the structure used to prevent this shift. Furthermore, according to the above structure, by extending the axial length of the guide portion 7c fitted into the filling ring 41, that is, the fitting length between the filling ring 41 and the guide portion 7c, it is possible to prevent the first movable iron core 7 from tilting within the filling ring 41, thereby hindering the smooth up-and-down movement of the second movable iron core 8. Therefore, according to the above solenoid S1, it is possible to more reliably prevent the first movable iron core 7 from hindering the smooth up-and-down movement of the second movable iron core 8.

[0118] However, the structure used to limit the radial (orthogonal to the axial direction of the coil 4) offset of the first movable iron core 7 relative to the first fixed iron core 5 and the second fixed iron core 6 is not limited to this and can be modified appropriately. Figure 5 , 6 This section describes a modified example of the structure used to limit the radial (orthogonal to the axial direction of the coil 4) offset of the first movable iron core 7 relative to the first fixed iron core 5 and the second fixed iron core 6. Hereinafter, various modified examples of the solenoid S1 according to this embodiment will be specifically described.

[0119] In the first modified example of the solenoid S1 in this embodiment, such as Figure 5 As shown, a recess 5a is formed on the first fixed iron core 5, opening toward the first movable iron core 7. Furthermore, replacing... Figure 3 The guide portion 7c shown has a first movable iron core 7 with a guide portion 7e extending axially from the front end of the inner cylinder portion 7b. This guide portion 7e is slidably inserted into the recess 5a. At this time, the sliding gap formed between the guide portion 7e and the peripheral wall of the recess 5a is very small, and the difference between the diameter of the peripheral wall of the recess 5a and the outer diameter of the guide portion 7e is smaller than the difference between the inner diameter of the outer cylinder portion 8b and the outer diameter of the inner cylinder portion 7b.

[0120] According to the above structure, by engaging the recess 5a of the first fixed core 5 with the guide portion 7e, the radial (orthogonal to the axial direction of the coil 4) displacement of the first movable core 7 relative to the first fixed core 5 and the second fixed core 6 can be prevented, and the structure to prevent this displacement can be easily implemented. Furthermore, according to the above structure, if the axial length of the guide portion 7e is extended to increase the engagement length, the tilting of the first movable core 7 within the filling ring 41 can be suppressed, and the situation where the first movable core 7 obstructs the smooth up-and-down movement of the second movable core 8 can be more effectively prevented.

[0121] Next, in a second variation of the solenoid S1 of this embodiment, as follows: Figure 6As shown, a tube 50 protruding towards the first movable core 7 is mounted on the first fixed core 5. Furthermore, the tube 50 is slidably inserted into the inner side of the inner cylinder portion 7b of the first movable core 7. At this time, the sliding gap formed between the tube 50 and the inner cylinder portion 7b is very small, and the difference between the inner diameter of the inner cylinder portion 7b and the outer diameter of the tube 50 is less than the difference between the inner diameter of the outer cylinder portion 8b and the outer diameter of the inner cylinder portion 7b.

[0122] According to the above structure, by fitting the tube 50 provided on the first fixed iron core 5 with the cylindrical portion 7b of the first movable iron core 7, the radial (direction orthogonal to the center line X of the coil 4) offset of the first movable iron core 7 relative to the first fixed iron core 5 and the second fixed iron core 6 can be prevented, and the structure to prevent this offset can be easily realized. Furthermore, according to the above structure, if the axial length of the tube 50 is extended to increase the fitting length, the tilting of the first movable iron core 7 within the filling ring 41 can be suppressed, and the situation where the first movable iron core 7 hinders the smooth up-and-down movement of the second movable iron core 8 can be more effectively prevented.

[0123] Furthermore, in this embodiment, the solenoid S1 and the valve core (valve body) 3 of the pressure control channel p2 together constitute the solenoid valve V. Moreover, in the direction of closing the pressure control channel p2, the solenoid S1 applies a force to the valve core (valve body) 3 generated when the coil 4 is energized, which attracts the second movable iron core 8 towards the second fixed iron core 6. Therefore, by changing the amount of current supplied to the solenoid S1, the opening pressure of the solenoid valve V can be adjusted, and the pressure upstream of the solenoid valve V can be set as the opening pressure of the solenoid valve V.

[0124] 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 target. 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 core 3 can be. Additionally, as described above, in the solenoid S1 of this embodiment, even when not energized, the spring 9 can apply force to the target in the same direction as the thrust when energized. Thus, in the solenoid valve V equipped with the solenoid S1 of this embodiment, the valve opening pressure when not energized can be determined according to the specifications of the spring 9.

[0125] Furthermore, the solenoid valve V, which includes the solenoid S1 of this embodiment, is disposed in the buffer D. In addition to the solenoid valve V, the buffer D also includes: a cylinder 1; a piston rod 11 axially movably inserted into the cylinder 1; a main passage M for supplying liquid flow when the cylinder 1 and the piston rod 11 move relative to each other axially; a main valve body 2 for opening and closing the main passage M; a pressure inlet passage p1 with a throttle O midway through which pressure is reduced and guided to the back of the main valve body 2 in the main passage M; and a pressure control passage p2 connected downstream of the throttle O in the pressure inlet passage p1, and provided with the aforementioned solenoid valve V.

[0126] According to the above structure, when the cylinder 1 and the piston rod 11 move relative to each other in the axial direction, the main valve body 2 applies resistance to the liquid flow through the main channel M, and a damping force is generated due to this resistance. Furthermore, since the back pressure of the main valve body 2 is set to the opening pressure of the solenoid valve V, the back pressure of the main valve body 2 can be adjusted by changing the amount of current supplied to the solenoid S1. Moreover, the higher the back pressure of the main valve body 2, the more difficult it is to open the first valve body portion 2A of the main valve body 2, and the greater the damping force generated on the extension side. Therefore, according to the above structure, the magnitude of the generated damping force on the extension side can be adjusted by changing the amount of current supplied to the solenoid S1.

[0127] Furthermore, as described above, in the solenoid valve V including the solenoid S1 of this embodiment, the greater the current supplied to the solenoid S1, the higher the opening pressure of the solenoid valve V. Therefore, in the buffer D equipped with the solenoid valve V including the solenoid S1 of this embodiment, the greater the current supplied to the solenoid S1, the higher the back pressure of the main valve body 2, and the greater the damping force generated on the extension side.

[0128] In other words, in the aforementioned buffer D, since the amount of current supplied to the solenoid S1 is small, the damping force generated on the elongation side can be reduced. Therefore, when the aforementioned buffer D is used in the vehicle suspension, the power consumption during normal driving can be reduced. In addition, this can suppress the heating of the solenoid S1 and reduce the temperature change of the buffer D, thereby reducing the change in damping force characteristics (damping force characteristics relative to piston speed) caused by changes in liquid temperature.

[0129] Furthermore, as described above, in the solenoid valve V including the solenoid S1 of this embodiment, the valve opening pressure when not energized can be determined according to the specifications of the spring 9. Therefore, in the buffer D equipped with 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 not energized. Thus, in the buffer D, even when the solenoid S1 experiences a power failure, insufficient damping force on the extension side can be prevented. Furthermore, in the buffer D, a pressure control channel p2 can be provided as the channel connected to the back pressure chamber L4 and setting the back pressure of the main valve body 2. It is not necessary to switch the channel connected to the back pressure chamber L4 when the solenoid S1 is energized and de-energized, so the structural complexity of the buffer D can be suppressed and the cost reduced.

[0130] In this embodiment, the back pressure of the main valve body 2 is controlled only by the solenoid valve V when the buffer D extends, and when it retracts, the thrust of the solenoid S1 in the solenoid valve V is directly applied to the main valve body 2 in the closing direction. However, it is also possible to control the back pressure of the main valve body by the solenoid valve V when the buffer D retracts.

[0131] Furthermore, the rod that enters or exits cylinder 1 does not necessarily have to be a piston rod equipped with a piston, and the position of the main valve body that controls the back pressure using solenoid valve V is not limited to the piston section. For example, if the buffer has a reservoir as described above, the channel connecting the extension side chamber or the compression side chamber to the reservoir can be used as the main channel, the main valve body can be installed, and the back pressure of the main valve body can be controlled using solenoid valve V. In addition, if the buffer is a unidirectional type, and the liquid circulates unidirectionally in the order of extension side chamber, reservoir, and compression side chamber during its extension and retraction, the circulation channel connecting the extension side chamber and the reservoir can be used as the main channel, the main valve body can be installed, and the back pressure of the main valve body can be controlled using solenoid valve V.

[0132] <Second Implementation Method>

[0133] Next, the explanation Figure 7 The solenoid S2 shown is from the second embodiment of the present invention. The solenoid S2 in this embodiment, like the solenoid S1 in the first embodiment, is used in a solenoid valve to... Figure 2 The solenoid S1 of the first embodiment shown is directly replaced by the solenoid S2 of this embodiment. Furthermore, the basic structure of the solenoid S2 in this embodiment is the same as that of the solenoid S1 in the first embodiment. Common structures will be marked with the same symbols, and detailed descriptions will be omitted.

[0134] The main difference between the solenoid S2 in this embodiment and the solenoid S1 in the first embodiment lies in the reversed arrangement of the first movable iron core and the second movable iron core. More specifically, in this embodiment, the first movable iron core 7A has: an inner cylinder portion 7f and an outer cylinder portion 7g arranged in two layers; a connecting portion 7h connecting one axial end of them; and an inner bottom 7i located at the other end of the inner cylinder portion 7f, with the inner bottom 7i facing downward (towards the second fixed iron core 6), so that the outer cylinder portion 7g slides in contact with the inner circumference of the filling ring 41. On the other hand, the second movable iron core 8A is a bottomed cylindrical shape, having an outer bottom 8d and a middle cylinder portion 8e standing upright on the outer periphery of the outer bottom 8d, with the outer bottom 8d facing downward (towards the second fixed iron core 6), and the middle cylinder portion 8e slides in contact with the inner circumference of the outer cylinder portion 7g of the first movable iron core 7A.

[0135] A through-hole 7j, extending through its thickness, is formed on the inner bottom 7i of the first movable iron core 7A, allowing liquid to move relatively unimpeded within it. This prevents liquid from being trapped on the upper side (the side of the first fixed iron core 5) of the first movable iron core 7A, ensuring smooth vertical movement of the first movable iron core 7A. A spring 9 is inserted inside the inner cylinder portion 7f of the first movable iron core 7A. In this embodiment, the spring 9 is a helical spring, with one end abutting against the inner bottom 7i. The other end of the spring 9 is supported by the first fixed iron core 5, and the spring 9 exerts a downward force on the first movable iron core 7A.

[0136] Furthermore, a through-hole 8f extending through its thickness is formed on the outer bottom 8d of the second movable core 8A, allowing liquid to move relatively unimpeded within the through-hole 8f. Additionally, the inner diameter of the intermediate cylinder portion 8e of the second movable core 8A is larger than the outer diameter of the inner cylinder portion 7f of the first movable core 7A, forming an annular gap between the intermediate cylinder portion 8e and the inner cylinder portion 7f. Therefore, the space L8 formed on the upper front end of the intermediate cylinder portion 8e (on the side of the first fixed core 5) and the space L9 formed between the outer bottom 8d and the inner bottom 7a become a continuous space. Moreover, since the through-hole 8f extends into this continuous space, it is possible to prevent the liquid from being trapped in this space and generating a damping force that hinders the movement of the second movable core 8A.

[0137] Furthermore, in this embodiment, since the first movable iron core 7A moves up and down (axially) while its outer cylinder 7g is supported by the filling ring 41, it will not become eccentric relative to the filling ring 41 during its movement. Since the filling ring 41 is sandwiched between the first fixed iron core 5 and the second fixed iron core 6 and is fixed relative to the first fixed iron core 5 and the second fixed iron core 6, it is possible to prevent the first movable iron core 7A from shifting in a direction (radial) orthogonal to the center line of the coil due to the filling ring 41.

[0138] Furthermore, the second movable iron core 8A moves vertically (axially) while its intermediate cylinder portion 8e is supported by the outer cylinder portion 7g of the first movable iron core 7A. Thus, in the solenoid S2 of this embodiment, the first movable iron core 7A is inserted into the filling ring 41, and the second movable iron core 8A is further inserted into the inner side of the first movable iron core 7A. Therefore, radial displacement can be prevented when the first movable iron core 7A is attracted to the first fixed iron core 5, and radial displacement of the second movable iron core 8A can be prevented from being trapped between the radially displaced first movable iron core 7A and the filling ring 41. There is no need to worry about increased sliding resistance during movement due to the second movable iron core 8A being trapped between the radially displaced first movable iron core 7A and the filling ring 41.

[0139] In addition, in this embodiment, such as Figure 7 As shown in (b), a protrusion 7k protruding towards its center is provided on the inner circumference of the front end of the outer cylinder portion 7g of the first movable iron core 7A. This protrusion 7k holds the fluoropolymer sheet 70 within the inner circumference of the outer cylinder portion 7g. Therefore, the sliding properties between the intermediate cylinder portion 8e of the second movable iron core 8A and the outer cylinder portion 7g of the first movable iron core 7A become good. Furthermore, the material of the sheet 70 can be any material with good sliding properties and is not limited to fluoropolymer; it can be appropriately modified. Alternatively, the sheet 70 can be omitted, allowing the intermediate cylinder portion 8e to directly slide in contact with the inner circumference of the outer cylinder portion 7g.

[0140] Next, in this embodiment, leaf springs 90 and 91, which function as limiting parts, are arranged above and below the outer bottom 8d of the second movable iron core 8A. More specifically, the first limiting part, i.e., the upper leaf spring 90, is located between the outer bottom 8d of the second movable iron core 8A and the inner bottom 7i of the first movable iron core 7A, which is vertically opposite to it, and the second limiting part, i.e., the lower leaf spring 91, is located between the outer bottom 8d of the second movable iron core 8A and the second fixed iron core 6, which is vertically opposite to it.

[0141] Furthermore, when the first movable core 7A moves downward relative to the second movable core 8A, its inner bottom 7i abuts against the leaf spring 90. This restricts the downward movement of the first movable core 7A relative to the second movable core 8A, and subsequently, the first movable core 7A and the second movable core 8A move downward as a single unit. Additionally, when the second movable core 8A moves downward, its outer bottom 8d abuts against the leaf spring 91, compressing it and preventing further downward movement.

[0142] Furthermore, a through hole is formed in the center of the second fixed iron core 6, through which the shaft portion 3a of the valve core 3 can be freely inserted. Moreover, the front end of the shaft portion 3a abuts against the outer bottom 8d of the second movable iron core 8A. Thus, when the coil is de-energized, the first movable iron core 7A moves downward under the force of the spring 9 and abuts against the second movable iron core 8A via the leaf spring 90. Therefore, the valve core 3 experiences a downward force generated by the force of the spring 9. Conversely, when the coil is energized, attracting the first movable iron core 7A to the first fixed iron core 5 and the second movable iron core 8A to the second fixed iron core 6, although the spring 9 is compressed by the first movable iron core 7A and its force is not transmitted to the valve core 3, the valve core 3 experiences a downward force generated by the force attracting the second movable iron core 8A.

[0143] Furthermore, the first limiting part, i.e., the leaf spring 90, restricts the approach between the inner bottom 7i of the first movable iron core 7A and the outer bottom 8d of the second movable iron core 8A, which is vertically (axially) opposite to it, preventing the first movable iron core 7A and the second movable iron core 8A from attracting each other when the coil is energized. Similarly, the second limiting part, i.e., the leaf spring 91, restricts the approach between the outer bottom 8d of the second movable iron core 8A and the second fixed iron core 6, which is vertically (axially) opposite to it, preventing the second movable iron core 8A from attracting onto the second fixed iron core 6 when the coil is energized. In addition, the first and second limiting parts are not limited to leaf springs 90 and 91 respectively, and can be modified in the same way as in the first embodiment.

[0144] On the other hand, there is no limiting part between the first fixed iron core 5 and the first movable iron core 7A, and when the coil is energized, the first movable iron core 7A is attracted to the first fixed iron core 5. Thus, if the first movable iron core 7A is attracted to the first fixed iron core 5 when the coil is energized, the posture of the first movable iron core 7A can be stably maintained. In this posture, the first movable iron core 7A compresses the spring 9, and the force of the spring 9 is not transmitted to the second movable iron core 8A. However, the first movable iron core 7A does not necessarily have to be attracted to the first fixed iron core 5 when the coil is energized.

[0145] The relationship between the current supplied to the solenoid S2 in this embodiment and the force exerted by the solenoid S2 on the valve core (target) 3 is the same as that of the solenoid S1 in the first embodiment. Figure 4 As shown. Furthermore, the operation of the buffer equipped with the solenoid valve including the solenoid S2 according to this embodiment is the same as the operation of the buffer D equipped with the solenoid valve V including the solenoid S1 according to the first embodiment.

[0146] The following describes the effects of the solenoid S2 according to this embodiment. Furthermore, since the structure is the same as that of the solenoid S1 in the first embodiment, it naturally has the same effects, and detailed descriptions are omitted here. In addition, the effects of the solenoid valve equipped with the solenoid S2 according to this embodiment and the buffer equipped with the solenoid valve containing the solenoid S2 are the same as those of the solenoid S1, the solenoid valve V equipped with the solenoid S1, and the buffer D equipped with the solenoid valve V containing the solenoid S1 in the first embodiment, and detailed descriptions are omitted here.

[0147] The solenoid S2 according to this embodiment includes: a coil; a first fixed iron core 5 located at one end of the coil's axial direction; a second fixed iron core 6 located at the other end of the coil's axial direction and having a gap with the first fixed iron core 5; a first movable iron core 7A disposed between the first fixed iron core 5 and the second fixed iron core 6, which is attracted by the first fixed iron core 5 when the coil is energized; a second movable iron core 8A disposed between the first fixed iron core 5 and the second fixed iron core 6, which is attracted by the second fixed iron core 6 when the coil is energized; a spring 9 that applies force to the first movable iron core 7A toward the second fixed iron core 6; and a leaf spring (limiting part) 90 that limits the movement of the first movable iron core 7A relative to the second movable iron core 8A toward the second fixed iron core 6. Furthermore, the movement of the first movable iron core 7A relative to the first fixed iron core 5 and the second fixed iron core 6 in a direction orthogonal to the axial direction of the coil is limited.

[0148] According to the above configuration, when the solenoid S2 is not energized, the first movable iron core 7A moves towards the second fixed iron core 6 under the force of the spring 9. When the movement of the first movable iron core 7A relative to the second movable iron core 8A towards the second fixed iron core 6 is restricted by the leaf spring 90, the first movable iron core 7A and the second movable iron core 8A become one unit and move towards the second fixed iron core 6. Therefore, when the solenoid S2 is not energized, the force of the spring 9 is transmitted to the second movable iron core 8A through the first movable iron core 7A and the leaf spring 90.

[0149] On the other hand, when solenoid S2 is energized, if the first movable iron core 7A is attracted by the first fixed iron core 5 and moves in the direction of attraction, then spring 9 is compressed by the first movable iron core 7A, and the force of spring 9 is not transmitted to the second movable iron core 8A. Furthermore, when solenoid S2 is energized, the second movable iron core 8A is attracted by the second fixed iron core 6, and the greater the current supplied to solenoid S2, the greater the force attracting the second movable iron core 8A to the second fixed iron core 6.

[0150] Therefore, if the force attracting the second movable iron core 8A is applied as a thrust to the target object such as the valve core 3 when the solenoid S2 is energized, the greater the current supplied to the solenoid S2, the greater the thrust applied to the target object; conversely, the smaller the current supplied to the solenoid S2, the smaller the thrust applied to the target object. Furthermore, when not energized, the force of the spring 9 acts on the target object via the first movable iron core 7A, the leaf spring (restriction part) 90, and the second movable iron core 8A. Since the direction of the force of the spring 9 is the same as the direction of the force attracting the second movable iron core 8A when the solenoid S2 is energized, according to the above structure, even when the solenoid S2 is not energized, a force can be applied to the target object in the same direction as when it is energized.

[0151] Furthermore, according to the above structure, as described above, when the solenoid S2 is energized, if the first movable iron core 7A moves towards the first fixed iron core 5 against the force of the spring 9, the force exerted by the spring 9 is not transmitted to the second movable iron core 8A, and therefore not to the valve core (target) 3. Thus, the thrust of the solenoid S2 when energized and the force exerted on the target by the spring 9 when not energized can be freely set separately. Additionally, although the spring 9 is a helical spring in this embodiment, it can also be a spring other than a helical spring, such as a disc spring.

[0152] Furthermore, in this embodiment, the movement of the first movable core 7A of the solenoid S2 relative to the first fixed core 5 and the second fixed core 6 in a direction orthogonal to the axial direction of the coil (along the direction of the coil's centerline X) is restricted. In other words, the first movable core 7A will not move radially relative to the first fixed core 5 and the second fixed core 6 of the coil. Therefore, the movement of the second movable core 8A is not hindered by the radially offset first movable core 7A, ensuring smooth up-and-down movement of the second movable core 8A. As a result, as described above, when the force attracting the second movable core 8A is applied as a thrust to the target object, it is possible to suppress the hysteresis of the thrust relative to the current supplied to the solenoid S2, and the thrust can be easily controlled.

[0153] Furthermore, the solenoid S2 according to this embodiment includes an annular filling ring 41, which is installed between the first fixed core 5 and the second fixed core 6. Moreover, the first movable core 7A has: an inner cylinder portion 7f and an outer cylinder portion 7g arranged in two layers; a connecting portion 7h connecting one axial end of the inner cylinder portion 7f and the outer cylinder portion 7g; and an inner bottom 7i located at the other end of the inner cylinder portion 7f, which is slidably inserted into the inner side of the filling ring 41 with the inner bottom 7i facing the second fixed core 6. On the other hand, the second movable core 8A is a bottomed cylindrical shape, having an outer bottom 8d and an intermediate cylinder portion 8e standing on the outer periphery of the outer bottom 8d with an inner diameter larger than the outer diameter of the inner cylinder portion 7f of the first movable core 7A. The intermediate cylinder portion 8e is slidably inserted into the inner side of the outer cylinder portion 7g of the first movable core 7A with the outer bottom 8d facing the second fixed core 6. Furthermore, the spring 9 is installed between the inner bottom 7i and the first fixed core 5, with one end inserted into the inner cylinder 7f of the first movable iron core 7A.

[0154] According to the above structure, when the coil is energized, the magnetic circuit passes through the first fixed iron core 5, the first movable iron core 7A, the second movable iron core 8A, and the second fixed iron core 6, thereby attracting the first movable iron core 7A to the first fixed iron core 5 and attracting the second movable iron core 8A to the second fixed iron core 6. Furthermore, a space for accommodating the spring 9 can be ensured inside the first movable iron core 7A.

[0155] Furthermore, according to the above configuration, when the first movable core 7A moves towards the second fixed core 6, the inner bottom 7i of the first movable core 7A approaches the outer bottom 8d of the second movable core 8A. Therefore, if the leaf spring (restricting part) 90 is configured to restrict their movement in the approach direction, the movement of the first movable core 7A relative to the second movable core 8A towards the second fixed core 6 can be restricted. Moreover, to configure the leaf spring 90 in this way, for example, it is easy to configure the leaf spring 90 between the inner bottom 7i of the first movable core 7A and the outer bottom 8d of the second movable core 8A, as in this embodiment. In other words, according to the above structure, the leaf spring (restricting part) 90 can be easily configured.

[0156] Furthermore, in the solenoid S2 described above, the outer cylinder portion 7g of the first movable iron core 7A is slidably inserted into the filling ring 41, and the middle cylinder portion 8e of the second movable iron core 8A is slidably inserted into the inner side of the outer cylinder portion 7g of the first movable iron core 7A. Thus, since the first movable iron core 7A is inserted into the filling ring 41, and the second movable iron core 8A is further inserted into the inner side of the first movable iron core 7A, the first movable iron core 7A will not experience radial displacement when attracted to the first fixed iron core 5, and the second movable iron core 8A will not be trapped between the radially displaced first movable iron core 7A and the filling ring 41. Therefore, according to the above structure, it is possible to prevent the second movable iron core 8A from being trapped between the radially displaced first movable iron core 7A and the filling ring 41, which would increase the sliding resistance during its movement and hinder the smooth up-and-down movement of the second movable iron core 8A.

[0157] The preferred embodiments of the present invention have been described in detail above, but modifications, variations and alterations can be made without departing from the scope of the claims.

[0158] This application claims priority based on Japanese Patent Application No. 2019-163879, filed with the Japan Patent Office on September 9, 2019, the entire contents of which are incorporated herein by reference.

[0159] Symbol Explanation

[0160] D buffer

[0161] M Main Channel

[0162] O Throttling

[0163] p1 Pressure Inlet Channel

[0164] p2 Pressure control channel

[0165] S1, S2 solenoids

[0166] V Solenoid valve

[0167] 1 cylinder

[0168] 2. Main valve body

[0169] 3. Valve core (valve body)

[0170] 4 coils

[0171] 5 First fixed iron core

[0172] 5a recess

[0173] 6 Second fixed iron core

[0174] 7.7A First Movable Iron Core

[0175] 7a, 7i Inner bottom

[0176] 7b, 7f Inner cylinder section

[0177] 7c, 7e Guiding section

[0178] 7g outer cylinder

[0179] 7h Connecting section

[0180] 8,8A Second Movable Iron Core

[0181] 8a, 8d Outer bottom

[0182] 8b outer cylinder part

[0183] 8e Intermediate cylinder section

[0184] 9 Springs

[0185] 11. Piston rod (rod)

[0186] 41 Filler ring

[0187] 50 tubes

[0188] 90 Leaf Spring (Restriction Section)

Claims

1. A solenoid characterized in that, Possessing: a coil; a first fixed core on one end side in the axial direction of the coil; a second fixed core on the other end side in the axial direction of the coil, with a gap from the first fixed core; a ring-shaped packing ring installed between the first fixed core and the second fixed core; a first movable core disposed between the first fixed core and the second fixed core, attracted to the first fixed core by energizing the coil; a second movable core disposed between the first fixed core and the second fixed core, attracted to the second fixed core by energizing the coil; a spring that exerts a force on the first movable core toward the second fixed core side; and a restriction portion that restricts movement of the first movable core toward the second fixed core side relative to the second movable core, movement of the first movable core relative to the first fixed core and the second fixed core in a direction orthogonal to the axial direction of the coil is restricted, the first movable core has an inner cylinder portion and an outer cylinder portion disposed in two layers, a connecting portion connecting one end of the inner cylinder portion and the outer cylinder portion in the axial direction, and an inner side bottom portion on the other end of the inner cylinder portion, the inner side bottom portion being slidably inserted into the inner side of the packing ring toward the second fixed core side, the second movable core is a bottomed cylinder having an outer side bottom portion and an intermediate cylinder portion with an inner diameter larger than the outer diameter of the inner cylinder portion, the outer side bottom portion being oriented toward the second fixed core side, and the intermediate cylinder portion being slidably inserted into the inner side of the outer cylinder portion, the spring is installed between the inner side bottom portion and the first fixed core with one end side inserted into the inner side of the inner cylinder portion.

2. An electromagnetic valve provided with the solenoid of claim 1 in the middle of a pressure control passage, provided with a valve body for opening and closing the pressure control passage, the solenoid exerts a force on the valve body in the direction of closing the pressure control passage, the force attracting the second movable core toward the second fixed core side when the coil is energized.

3. A shock absorber provided with the electromagnetic valve of claim 2, and provided with: a cylinder; a rod slidably inserted into the cylinder in the axial direction; a main passage for liquid flow when the cylinder and the rod move relative to each other in the axial direction; a main valve body that opens and closes the main passage; a pressure introduction passage provided with a restrictor in the middle, reducing and introducing the pressure on the upstream side of the main valve body of the main passage to the back surface of the main valve body; and the pressure control passage connected to the downstream side of the restrictor of the pressure introduction passage, and provided with the electromagnetic valve.

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