JP5862100B2 - solenoid - Google Patents

Description

  The present invention relates to a solenoid that increases a magnetic attractive force for attracting a plunger.

Conventionally, a solenoid is used as one for driving a driven member such as a valve for controlling a fluid such as liquid or gas. Specifically, a current is passed through a copper wire wound around a coil bobbin to generate a magnetic force as an attractive force on the attracting surface of the magnetic member, and the driven member is attracted to the attracting surface by the magnetic force. Is to drive.
However, problems such as the above-described small magnetic attractive force have been pointed out. For example, a side ring may be provided to stably converge the magnetic flux on the plunger. However, since a coil bobbin as a container is formed between the side ring and the plunger, the leakage of the magnetic flux increases and the attractive force There was a problem that became smaller.
On the other hand, a center post made of a magnetic material, a cylindrical sleeve made of a non-magnetic material, and a cylindrical side ring made of a magnetic material, which are arranged in series in the inner cylinder portion of the cylindrical coil member And a solenoid that includes a plunger that is reciprocated in the axial direction inside the sleeve and the side ring (see, for example, Patent Document 1).
In the solenoid device of the electromagnetic control valve, in particular, in the electromagnetic capacity control valve in which the bellows type pressure sensitive element is incorporated, the plunger is attracted to the change of the winding current (coil current) without increasing the size of the solenoid portion. There is a demand for a high rate of change in magnetic attraction between the children.
However, the magnetic attractive force acting between the plunger attractors becomes stronger as the number of lines of magnetic force that effectively pass through the plunger increases in the closed loop magnetic path. Since this is not sufficient, there is a problem that the magnetic attractive force is weak and the rate of change of the magnetic attractive force between the plunger and the attractor with respect to the change of the winding current is small.
On the other hand, the solenoid structure of the electromagnetic control valve has a closed loop magnetic path that passes through the winding-attractor-magnetic path configuration outer box-magnetic path configuration member-plunger-attractor, and the coil bobbin is magnetized. Since the bobbin inner peripheral wall including the stepped portion has a stepped portion that receives the cylindrical portion of the path constituent member between the plunger case and the plunger case, the entire thickness of the bobbin inner peripheral wall is substantially the same. There has been proposed an electromagnetic control solenoid structure in which the number of windings can be increased without increasing the outer dimension of the wire and the excitation force is increased (see, for example, Patent Document 2).

JP 10-89522 A (paragraph [0014], FIG. 1) JP 2002-250456 A (paragraph [0012], FIG. 2)

However, in Patent Document 1, since the current number of turns of the coil itself does not change, there is a problem that there is a limit to increasing the attractive force.
On the other hand, in patent document 2, the winding installation effective area is enlarged by making the whole wall thickness of the bobbin inner peripheral wall including the stepped portion substantially the same, and the number of turns of the coil is increased accordingly. However, if the stepped portion is not formed in the first place, the entire thickness of the bobbin inner peripheral wall is essentially the same, and the effective area for installing the winding cannot be increased, and the number of turns of the coil cannot be increased. .
Therefore, the outer diameter of the coil bobbin inner wall is further reduced to reduce the outer diameter of the coil bobbin, increase the volume that can be wound with the conductor without increasing the outer dimensions of the winding, increase the number of turns, and increase the magnetic attractive force. It is possible to increase.
However, if a fluid such as oil is interposed between the inner peripheral surface of the coil bobbin and the plunger, if the coil bobbin is inadvertently reduced in outer diameter, it may not be able to withstand the pressure of the fluid and damage the coil bobbin. There is a problem that there is.
Even if the stepped portion is formed, there is a possibility that almost no increase in the number of turns can be expected depending on the size of the stepped portion because the outer shape of the solenoid is not enlarged. Furthermore, in order to make the entire wall thickness of the inner peripheral wall of the coil bobbin substantially the same, the entire outer diameter of the coil bobbin around which the coil is wound must be a diameter that can withstand the pressure of the fluid, and a sufficient increase in the number of turns is necessary. There is a problem that I can not hope for.

  In view of the circumstances as described above, the object of the present invention is to increase the number of turns without increasing the outer shape of the solenoid, and to increase the suction force that the plunger is attracted to the suction surface by the magnetic force, and the strength required for the coil bobbin. It is to provide a solenoid capable of ensuring the above.

In order to achieve the above object, a solenoid according to an embodiment of the present invention includes a plunger, a coil bobbin, and a coil.
The plunger includes a shaft portion and a main body portion having an outer diameter larger than the outer diameter of the shaft portion in one axial direction.
The coil bobbin has a cylindrical shape having an inner peripheral surface and an outer peripheral surface, and the inner peripheral surface has a sliding surface that receives the pressure of the fluid by sliding the main body portion in the uniaxial direction via a fluid. The outer peripheral surface is provided with at least a first outer diameter portion corresponding to the sliding surface and an outer diameter smaller than the first outer diameter portion and provided on the shaft portion side away from the sliding surface. 2 outer diameter portions.
The coil is wound around the first outer diameter portion and the second outer diameter portion.

  Here, the shaft portion and the main body portion of the plunger are connected side by side in a uniaxial (center axis) direction so that their center axes coincide with each other. Of course, the shaft portion and the main body portion may be integrally formed.

The inner peripheral surface of the coil bobbin is formed with a portion where the shaft portion of the plunger is accommodated and a portion where the main body portion is accommodated, and the portion where the shaft portion is accommodated is the inner peripheral surface of the recess whose tip is closed. A spring that biases the shaft portion toward the main body portion is provided. The inner diameter of the portion in which the shaft portion is accommodated is smaller than the inner diameter of the portion in which the main body portion is accommodated, and the difference in inner diameter becomes a magnetic portion that attracts the main body portion of the plunger by magnetic force, thereby forming an attraction surface. .
Further, the inner peripheral surface of the portion in which the main body portion is accommodated has a sliding surface that slides with the main body portion, and at least a fluid made of oil or the like is interposed between the sliding surface and the main body. . Accordingly, since the coil bobbin is normally sealed, the pressure by the oil or the like is applied to the sliding surface.

The outer peripheral surface of the coil bobbin has a first outer diameter portion and a second outer diameter portion, and the first outer diameter portion is formed corresponding to at least the sliding surface of the inner peripheral surface, and is from the central axis of the coil bobbin. It is provided so as to overlap the sliding surface in the radially outward direction. Furthermore, the first outer diameter portion extends slightly from the portion overlapping the sliding surface in the axial direction, and has a diameter equal to or greater than a predetermined outer diameter including the extending portion.
Here, the predetermined outer diameter is an outer diameter that can secure a thickness sufficient to withstand a force (pressure) mainly in a radially outward direction that the sliding surface receives from a fluid between the plunger and a material. The predetermined outer diameter varies depending on the diameter of the plunger and the like. Of course, the said 1st outer diameter part should just be a fixed diameter or more, and does not need to be the same diameter altogether. There may be a portion with a diameter larger than a certain diameter in the middle, but the portion where the conducting wire such as the copper wire of the first outer diameter portion is wound is formed with a predetermined diameter in order to secure the number of turns. Is desirable.

The second outer diameter portion is provided as an outer peripheral surface of the coil bobbin continuously from the first outer diameter portion, and is separated from the sliding surface in a direction parallel to the uniaxial direction that is the central axis of the coil bobbin and the plunger. The outer diameter has begun.
In the portion away from the sliding surface (second outer diameter portion), the pressure in the radially outer direction is not applied by the fluid, so the thickness of the coil bobbin does not have to be the same as that of the first outer diameter portion. An outer diameter smaller than the outer diameter of the diameter portion, that is, an outer diameter smaller than the predetermined outer diameter is sufficient in terms of strength.

  The coil has a substantially cylindrical shape in which a conductive wire such as a copper wire is wound around the first outer diameter portion and the second outer diameter portion of the coil bobbin, and the outer peripheral surface thereof is substantially flush with the cylindrical outer peripheral surface. Yes. Of course, the outer peripheral surface of the coil need not be a cylindrical surface, and may be a versatile outer peripheral surface based on the shape of the plunger, such as a polygonal column outer peripheral surface.

Here, since the coil is wound up to the place where it contacts the first outer diameter portion and the second outer diameter portion of the coil bobbin, the first outer diameter portion and the second outer diameter portion are substantially connected to the inner peripheral surface of the coil. The coil may have a first inner diameter portion corresponding to the first outer diameter portion and a second inner diameter portion corresponding to the second outer diameter portion.
In other words, the inner diameter of the second inner diameter portion of the coil is smaller than the inner diameter of the first inner diameter portion, and the portion between the difference from the first inner diameter portion in the inner diameter direction (approached to the inner side (center axis side) from the first inner diameter portion). Since the conductive wire can be wound also on the portion), the number of turns per unit length of the coil can be increased. As a result, it is possible to increase the magnetic flux density and increase the magnetic attractive force.

For example, if the conducting wire is wound from the second outer diameter portion, which is smaller than the outer diameter of the first outer diameter portion of the coil bobbin, the outer dimension of the coil itself is reduced without changing the overall length of the conducting wire, and the number of turns is also increased. The inner diameter portion of the coil can be increased by the smaller circumferential length. In this case, since the resistance of the coil does not change, the increase in the number of turns can directly increase the magnetic attractive force.
On the other hand, if the coil bobbin is wound from the second outer diameter portion so as not to change the outer dimensions of the coil, the entire length of the conductive wire becomes longer as it is wound around the portion protruding inward from the first inner diameter portion. Increase. However, the difference in the inner diameter direction of the coil all increases the number of turns. In addition, since the diameter of the increased number of turns is smaller than the inner diameter of the first inner diameter portion, the increase in the length of the conducting wire is also small, and the increase in the resistance value of the entire coil due to the increase in the length is also small. Even if the minute is taken into account, the magnetic attractive force can be increased by increasing the number of turns.

When a current is passed through the coil, the magnetic flux density generated in the coil increases as the number of turns of the conducting wire increases in the second inner diameter portion, and the increased magnetic flux increases in the magnetic portion described later on the second outer diameter side of the coil bobbin. The magnetic attractive force from the attractive surface is increased. The attracted surface of the plunger is driven more strongly by this increased magnetic attraction force, and the drive force drives a driven member connected to the plunger, for example, drives a fluid control valve.
In addition, it is not necessary to increase the outer dimension of the coil in order to increase the magnetic attraction force, and the second outer diameter portion having a smaller outer diameter is sufficiently away from the sliding surface. The magnetic attractive force can be increased without damaging the surface.
When the current is stopped, the magnetic attractive force disappears and the plunger is separated from the attractive surface of the coil bobbin by the biasing force of the spring, so that the fluid control valve can be returned to its original state by the driving force.

  The main body portion is provided with a tapered portion between the sliding portion that is slid on the sliding surface and the shaft portion so that the diameter decreases toward the shaft portion, and slides on the shaft portion. You may connect a part. Thereby, the magnetic flux generated in the coil can be received over a wide area, and the attractive force can be further increased.

  The outer diameter of the second outer diameter portion may be larger than the outer diameter of the sliding portion. As a result, the attracted surface of the plunger can receive the magnetic attractive force of the coil bobbin without waste, so that the magnetic attractive force can be reliably increased.

The coil bobbin includes a non-magnetic portion and a magnetic portion, the non-magnetic portion forms first and second outer diameter portions of the outer peripheral surface and at least a part of the sliding surface, and the magnetic portion is The suction surface may be formed so as to fit the tapered portion.
As a result, the magnetic flux generated in the coil flows from the attracting surface of the magnetic part to the main body without waste, and enters the magnetic part and finally returns to the coil, thereby forming a closed magnetic path, and more efficient magnetism. A suction force can be generated.

  As described above, in the present invention, it is possible to secure the strength required for the coil bobbin while increasing the number of turns of the coil without increasing the outer shape of the solenoid and increasing the suction force that the plunger is attracted to the suction surface by the magnetic force.

It is a fragmentary sectional view which shows the partial cross section of the solenoid which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a partial cross-sectional view showing a solenoid according to an embodiment of the present invention.

  The solenoid 1 includes a plunger 2, a cylindrical coil bobbin 3 that slidably holds the plunger 2, a coil 4 wound around the coil bobbin 3, an outer case 5, and a lid 6.

  As shown in FIG. 1, the plunger 2 includes a shaft portion 21, a main body portion 22 having a diameter larger than the diameter of the shaft portion 21, and an output portion 23 connected to the driven member in that order. The shaft portion 21 has a substantially cylindrical shape, and has a protrusion inserted into a spring described later at the tip.

  The main body portion 22 has a tapered portion 222 connecting the cylindrical sliding portion 221 and the above-described shaft portion 21 having a different diameter, and the tapered portion 222 has a truncated cone shape, A sliding portion 221 is provided on the bottom surface of the shaft portion 21.

  Here, the taper portion 222 constitutes a surface to be attracted by a magnetic force to an attracting surface of a magnetic portion of the coil bobbin 3 to be described later.

  As shown in FIG. 1, the coil bobbin 3 includes a magnetic portion 31 and a nonmagnetic portion 32, and the magnetic portion 31 includes a shaft portion side magnetic portion 311 and a main body portion side magnetic portion 312, and the nonmagnetic portion 32. By these, it is comprised integrally. The magnetic part 31 is made of electromagnetic soft iron (pure iron) or the like, and the nonmagnetic part 32 is made of stainless steel or the like. The shaft side magnetic part 311 is integrally formed with a large diameter part 3111 and a medium diameter part 3112 having a diameter smaller than the large diameter part 3111 and slightly larger than the outer diameter of the main body part 22.

  Here, a hollow cylindrical portion 3112a, which is a recess having an inner diameter slightly larger than the diameter of the shaft portion 21 from the middle diameter portion 3112 to a part of the large diameter portion 3111, is formed around the central axis O described above. A spring 3112c is provided inside. The spring 3112c urges the main body 22 and the output part 23 to the outside via the shaft part 21 of the plunger 2.

  The medium diameter portion 3112 has an absorption surface 3112b that is recessed inwardly at the end opposite to the large diameter portion 3111 so as to fit the tapered portion 222, with the central axis O as the center. Thereby, when the shaft part side magnetic part 311 is magnetized, the taper part 222 which is the plunger 2 is efficiently attracted to the attraction surface 3112b which is the magnetic part.

  Further, the main body side magnetic part 312 has a substantially cylindrical shape, and the medium diameter part 3121 and the large diameter part 3122 are integrally formed in the above-mentioned uniaxial direction, and the medium diameter part 3121 is formed as shown in FIG. A part of the sliding surface A1 is formed by sliding into the sliding surface side of the non-magnetic portion 32.

  That is, the outer peripheral surface of the medium-diameter portion 3121 of the main body portion side magnetic portion 312 is overlapped so that the nonmagnetic portion 32 covers it, while a part of the inner peripheral surface of the large-diameter portion 3122 is slid on the medium-diameter portion 3121 A sliding surface A2 is formed continuously with the surface A1, and a seal portion (described later) of the lid portion 6 is fitted into the inner peripheral surface of the remaining large-diameter portion 3122.

  Further, the non-magnetic portion 32 has a substantially cylindrical shape, and its outer peripheral surface forms the outer peripheral surface of the coil bobbin 3 as shown in FIG. 1, and the outer peripheral surface is different from the first outer diameter portion 321 and the first outer diameter. And a second outer diameter portion 322 having an outer diameter smaller by about 1 mm than the outer diameter portion 321. The second outer diameter portion 322 has a tapered step portion 3221 that is connected to the first outer diameter portion 321.

  Further, the inner peripheral surface 323 of the nonmagnetic portion 32 has the same inner diameter from the second outer diameter portion 322 to the middle of the first outer diameter portion 321, and the above-mentioned middle diameter portion from the middle of the first outer diameter portion 321. A portion having a slightly larger inner diameter is provided so that 3121 becomes the sliding surface A1. The medium-diameter portion 3121 of the main body side magnetic portion 312 is formed so as to enter between the inner peripheral surface 323 separated from the sliding surface A1.

  Further, the first outer diameter portion 321 having the larger outer diameter is separated from the sliding surface A on which the plunger 2 slides and the tip portion B of the suction surface 3112b of the shaft-side magnetic portion 311 as shown in FIG. To the large diameter portion 3111 side. Accordingly, the position of the tapered step portion 3221 is somewhat closer to the large diameter portion 3111 side than the tip portion B of the suction surface 3112b.

  From the above, the sliding surface A on which the outer peripheral surface of the sliding portion 221 described above slides through the oil 7 is the inner peripheral surface of the coil bobbin 3 as shown in FIG. Specifically, the sliding surface A is a sliding surface between the sliding surface A3 from the portion contacting the tip B of the suction surface 3112b on the inner peripheral surface of the nonmagnetic member 32 to the front where the inner diameter is large and the middle diameter portion 3121. The moving surface A1 and the sliding surface A2 of the inner peripheral surface of the large diameter portion 3122 are configured.

  In the coil 4, a copper wire as a conducting wire is wound around the outer peripheral surface between the large diameter part 3111 of the shaft part side magnetic part 311 of the coil bobbin 3 and the large diameter part 3122 of the main body part side magnetic part 312. The outer peripheral surface is formed to have a constant outer diameter that is slightly smaller than the outer peripheral surfaces of the large diameter portions 3111 and 3122.

  That is, since the coil 4 is wound with the copper wire until it comes into contact with the outer peripheral surface of the coil bobbin 3, the first outer diameter portion 321 and the second outer diameter portion 322 can be substantially used as the inner peripheral surface of the coil 4. That is, the coil 4 has a first inner diameter portion 41 corresponding to the first outer diameter portion 321 and a second inner diameter portion 42 corresponding to the second outer diameter portion 322. A tapered step 421 corresponds to the tapered step 3221.

  Here, as shown in FIG. 1, since the diameter of the second outer diameter portion 322 is smaller than the first outer diameter portion 321, the inner diameter of the second inner diameter portion 42 is larger than the inner diameter of the first inner diameter portion 41 of the coil 4. Is getting smaller. Accordingly, a copper wire can be wound around a difference portion (a portion protruding inward from the first inner diameter portion 41) with respect to the first inner diameter portion 41 in the inner diameter direction, so the number of turns per unit length of the coil 4 can be reduced. It can be increased. As a result, it is possible to increase the magnetic flux density and increase the magnetic attractive force.

  Further, the inner peripheral surface of the second inner diameter portion 42 is wound inwardly by the coil 4, and as shown in FIG. 1, the diameter of the taper portion 222 attracted by magnetic force with respect to the central axis O. It is formed so as to be located in the radially outward direction from the outermost end portion C in the outer direction.

  The coil 4 includes a lead wire 43 that is electrically connected to a power supply unit (not shown), and ON / OFF of a current applied to the coil 4 is controlled by the power supply unit.

  The outer case 5 has a substantially cylindrical shape in which the large-diameter portion 3111 of the shaft portion-side magnetic portion 311 and the large-diameter portion 3122 of the main body-side magnetic portion 312 that are configured as the coil bobbin 3 are just contained. In addition, a stepped portion 51 in which the flange portion of the lid portion 6 fixed to the large diameter portion 3122 is accommodated is formed on the inner peripheral surface on one end side. The outer case 5 is fixed by a coil bobbin 3 and a screw 52.

  The lid portion 6 includes the seal portion 61, the flange portion 62, and the end portion 63 integrally formed in the uniaxial direction described above, and the seal portion 61 is connected to the plunger 2 by an O-ring 612 disposed in the groove portion 611. The space between the coil bobbin 3 is sealed. Further, the lid portion 6 is fixed to the coil bobbin 3 by fixing the flange portion 62 to the large diameter portion 3122 with a screw 621. Further, a part of the rod 231 of the output portion 23 of the plunger 2 protrudes from the lid portion 6 through a through-hole 631 provided in the end portion 63, and hydraulic control as a driven member (not shown) is performed on the protruding rod 231. Valves are connected.

  When the solenoid 1 of this embodiment was tested, even if the same current is applied as compared with the case where all the inner diameters of the first inner diameter portion 41 are formed as in the prior art, the attraction force that is the force for attracting the plunger 2 is About 14%. When the voltage was the same, the suction force was the same, but the temperature rise of the solenoid 1 could be lowered by 21 ° C.

  As described above, since the outer peripheral surface of the coil bobbin 3 has the first outer diameter portion 321 and the second outer diameter portion 322 having an outer diameter smaller than that of the first outer diameter portion 321, the coil 4 is connected to the second inner diameter portion. 42 can be further wound inwardly from the first inner diameter portion 41, and the number of turns of the copper wire can be increased accordingly. The amount of magnetic flux density generated in the coil 4 is increased by the increase in the number of turns of the conducting wire in the second inner diameter portion 42, and the increased magnetic force increases the magnetic attractive force from the attractive surface 3112b of the coil bobbin 3. Become. The taper portion 222 of the plunger 2 is driven more strongly by this increased magnetic attraction force, and the driving force drives a driven member connected to the plunger 2, for example, drives a fluid control valve. .

  Further, in the portion of the second inner diameter portion 42 having a smaller inner diameter than the first inner diameter portion 41, the winding of the copper wire has a small radius, so the length of the copper wire corresponding to the increased number of turns can be shortened, and the resistance value is also increased. Less. Therefore, the effect of the number of turns increased by the second inner diameter portion 42 is greater than the resistance value increased by maintaining the outer dimension of the coil 4, and as a result, the magnetic attractive force from the attractive surface 3112 b of the coil bobbin 3 is increased. Can be made. That is, the magnetic attractive force of the coil bobbin 3 can be increased without increasing the size of the outer shape of the solenoid 1.

  The second outer diameter portion 322 of the coil bobbin 3 is provided as an outer peripheral surface of the coil bobbin continuously to the first outer diameter portion 321, and the sliding surface A is parallel to the central axis O of the coil bobbin 3 and the plunger 2. The second outer diameter portion 322 starts away from the second portion. Therefore, even if the second outer diameter portion 322 has an outer diameter smaller than the outer diameter of the first outer diameter portion 321, for example, an outer diameter that is smaller by about 1 mm, the pressure by the oil 7 as a fluid is not applied. The coil bobbin 3 can be prevented from being damaged without enlarging the solenoid 1.

  Further, the inner peripheral surface 323 of the non-magnetic portion 32 is positioned slightly outward in the radial direction from the outermost end portion C in the radially outward direction with respect to the central axis O of the tapered portion 222 attracted by magnetic force as shown in FIG. doing. Therefore, the surface area of the tapered portion 222 that receives the magnetic lines of force generated by the coil 4 can be most effectively used, and the attractive force due to the magnetic force can be increased without increasing the outer shape of the solenoid 1.

  Further, the inner peripheral surface of the second inner diameter portion 42 is wound inwardly by the coil 4, and as shown in FIG. 1, the diameter of the taper portion 222 attracted by magnetic force with respect to the central axis O. It is formed so as to be located in the radially outward direction from the outermost end portion C in the outer direction. Thereby, the magnetic force lines generated by the coil 4 can be most efficiently advanced to the tapered portion 222, and the attractive force due to the magnetic force can be increased without increasing the outer shape of the solenoid 1.

  Next, the operation of the solenoid 1 described above will be described with reference to FIG.

  When no current is applied to the coil 4 via the lead wire 43 by the power supply unit, no magnetic flux is generated by the coil 4 and, as shown in FIG. The plunger 2 moves to the right as viewed in FIG. As the plunger 2 moves, the rod 231 also moves to close a fluid control valve as a driven member (not shown), for example.

  Next, when a current is applied to the coil 4 via the lead wire 43 by the power supply unit, a magnetic flux is generated by the coil 4 to generate a magnetic force on the attracting surface 3112b of the shaft side magnetic unit 311 and the taper of the plunger 2 Part 222 is aspirated.

  When the attractive force due to the magnetic force overcomes the urging force of the spring 3112c, the outer peripheral surface of the sliding part 221 is slid with the non-magnetic part 32, the medium diameter part 3121 and the large diameter part 3122 through the oil 7. It slides on surface A and moves to the left as seen in FIG. As a result, the rod 231 also moves to the left together, so that the fluid control valve is opened.

  Here, in FIG. 1, compared to the inner diameter of the first inner diameter portion 41 of the coil 4, the inner second inner diameter portion 42 has a large number of circles which are cross sections of the wound copper wire. The magnetic flux density generated due to the increase in the number of turns also increases. The increased magnetic flux density acts on the shaft side magnetic part 311, and an increased magnetic force is generated from the attracting surface 3112 b to act on the tapered part 222 of the plunger 2.

  Further, since the nonmagnetic portion 32 covers most of the outer peripheral surface excluding the large diameter portions 3111 and 3122 of the coil bobbin 3, the magnetic lines of force can work most efficiently and the attractive force can be further increased.

  The embodiment according to the present invention is not limited to the above-described embodiment, and various other embodiments are conceivable.

  For example, although the main body portion 22 of the plunger 2 according to the above-described embodiment has the tapered portion 222 that connects the columnar sliding portion 221 and the shaft portion 21 having a different diameter, The shaft portion 21 may be directly connected, or may be stepped instead of tapered. Furthermore, a curved surface may be formed. Various shapes of the main body can be applied depending on the usage form of the solenoid.

  In the above embodiment, the outer dimension of the coil 4 is maintained, but the first outer diameter portion 321 and the second outer diameter smaller than the first outer diameter portion 321 are made constant with the total length of the copper wire used being constant. You may wind around the outer diameter part 322. FIG. As a result, the outer diameter of the coil 4 itself can be reduced while the inner diameter portion of the coil 4 has a smaller circumferential length so that the number of turns can be increased. In this case, since the resistance of the coil 4 does not change, the increase in the number of turns can directly increase the magnetic attractive force.

DESCRIPTION OF SYMBOLS 2 ... Plunger 21 ... Shaft part 22 ... Main-body part 3 ... Coil bobbin 321 ... 1st outer diameter part 322 ... 2nd outer diameter part 4 ... Coil 7 ... Oil (equivalent to fluid)
A ... Sliding surface O ... Center axis (equivalent to one axis)

Claims (1)

A plunger having a shaft portion and a body portion having an outer diameter larger than the outer diameter of the shaft portion in one axial direction;
The main body is slidable on a sliding surface of an inner peripheral surface, and the sliding is performed with at least a first outer diameter portion provided corresponding to the sliding surface and an outer diameter smaller than the first outer diameter portion. A coil bobbin configured in a cylindrical shape having an outer peripheral surface including a second outer diameter portion provided on the shaft portion side away from the surface;
A coil wound around the outer peripheral surface ;
A solenoid having a fluid interposed between the plunger and the inner peripheral surface of the coil bobbin so that the main body can slide in the uniaxial direction by movement of the plunger by electromagnetic force. .

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