electromagnet

Abstract

To provide an electromagnet capable of reducing a power consumption at a conduction for sucking a movable iron core to a fixed iron core.SOLUTION: A yoke member 15 forming a fitting hole 22 slidably fitting a movable iron core 14 to an axial direction is provided. The yoke member 15 is made of a magnetic material in a cylinder shape, and one end to which the fitting hole 22 opens is oppositely arranged with a fixed iron core 7, and the other end is formed in a flat face H. An annular cross-sectional area S1 of the yoke member 15 and a circular cross-sectional area S2 of the movable iron core 14 are formed in an approximate same. A cylinder block 8 is structured by fixing the fixed iron core 7 and the yoke member 15 with a cylinder material 16 made of a non-magnetic material. An annular coil bobbin 20 to which a coil 19 is wound is fitted to the outside of the cylinder block 8. The coil bobbin 20 is covered with the cover member 10 made of the magnetic material in an approximate cup shape having a bottom face K, and the bottom face K of the cover member 10 is contacted to the flat face H of the yoke member 15.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electromagnet suitable for use in a solenoid valve. [Background technology]

[0002] In this type of electromagnet, a cylindrical block is attached to one end of a valve body with a spool inside, an annular block is fitted onto the cylindrical block, and a nut member screwed onto the end of the cylindrical block is tightened to sandwich the annular block between the valve body and the nut member. The cylindrical block is composed of a fixed core attached to the valve body, a cylindrical member in which the axial half of the fixed core side is nonmagnetic and the remaining axial half is magnetic, a movable core slidably inserted inside the cylindrical member, and a stopper fixed to the end of the cylindrical member. The annular block is formed by arranging a yoke at both axial ends of a coil bobbin wound with a coil, and a cylindrical body on the outer periphery of the coil bobbin, and molding the coil bobbin, yoke, and cylindrical body together with resin. A magnetic circuit is formed through the magnetic parts of the yoke, cylindrical body, fixed core, movable core, and cylindrical member, and when electricity is applied to the coil, an attractive force is generated that attracts the movable core to the fixed core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-70194 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in such conventional electromagnets, the cylindrical member is thin, so the magnetic cross-section through which the magnetic flux passes is small, and there is a radial gap between the magnetic part of the cylindrical member and the yoke, which causes magnetic loss and increases power consumption when current is applied.

[0005] An object of the present invention is to provide an electromagnet capable of reducing power consumption when a current is passed to attract a movable iron core to a fixed iron core. [Means for solving the problem]

[0006] In order to achieve this object, the present invention takes the following measures: In an electromagnet in which a movable core is attracted to a fixed core by an attractive force generated by energizing a coil, the movable core is disposed opposite the fixed core, and a yoke member is provided having a fitting hole formed therein into which the movable core is fitted so as to slide axially. The yoke member is cylindrical and made of a magnetic material, and one end of the yoke member into which the fitting hole opens is disposed opposite the fixed core, and the other end opposite the one end is formed into a flat surface. The yoke member has an annular cross-sectional area substantially equal to the circular cross-sectional area of ​​the movable core, and the area of ​​the flat surface is set larger than the cross-sectional area of ​​the annular cross-sectional area. The fixed core and the yoke member are fixed to each other with a cylindrical member made of a non-magnetic material to form a cylindrical block. An annular coil bobbin wound with a coil is fitted onto the cylindrical block, and a substantially cup-shaped cover member having a bottom and made of a magnetic material is provided to cover the coil bobbin, and the bottom surface of the cover member abuts against the flat surface of the yoke member. The yoke member has a protrusion protruding in the axial direction from the flat surface thereof, and the yoke member is provided with a push pin member which is manually operated to move the movable iron core toward the fixed iron core, and the push pin member is provided on the protrusion so as to be freely movable in the axial direction, and can be manually pushed in the axial direction from the outside. The electromagnet is characterized by the above.

[0007] In this case, the cover member may have a convex portion protruding in the axial direction from the flat surface of the yoke member, a through hole penetrating the convex portion may be formed in the bottom surface of the cover member, a nut member may be screwed onto the convex portion so as to be rotatable, and the bottom surface of the cover member may be pressed against the flat surface of the yoke member by rotating the nut member. The yoke member may also have a push pin member which is manually operated to move the movable core towards the fixed core, and the push pin member may be axially movable on the convex portion and manually pushed in the axial direction from the outside. Effect of the Invention

[0008] As described above in detail, the invention described in claim 1 provides a yoke member having a fitting hole formed therein into which a movable core is fitted so as to be slidable in the axial direction, the yoke member being cylindrical and made of a magnetic material, one end of the yoke member into which the fitting hole opens being disposed opposite the fixed core, and the other end opposite the one end being formed as a flat surface, the yoke member being formed so as to have an annular cross-sectional area substantially equal to the circular cross-sectional area of ​​the movable core, and the area of ​​the flat surface being greater than the annular cross-sectional area, the fixed core and the yoke member being fixed together with a cylindrical member made of a non-magnetic material to form a cylindrical block, an annular coil bobbin wound with a coil is fitted onto the cylindrical block, and the coil bobbin is covered with a cover member made of a magnetic material and having a substantially cup-like shape with a bottom surface, the bottom surface of the cover member being in contact with the flat surface of the yoke member, The yoke member has a protrusion protruding in the axial direction from the flat surface thereof, and the yoke member is provided with a push pin member which is manually operated to move the movable iron core toward the fixed iron core, and the push pin member is provided on the protrusion so as to be freely movable in the axial direction, and can be manually pushed in the axial direction from the outside. Therefore, because the annular cross-sectional area of ​​the yoke member is made large, approximately equal to the cross-sectional area of ​​the movable core, the magnetic cross section through which the magnetic flux passes can be made large, and because the yoke member and cover member which form the magnetic circuit that generates the attractive force that attracts the movable core to the fixed core abut against each other and have no gaps, magnetic loss can be reduced compared to conventional electromagnets in which a radial gap exists between the magnetic part of the cylindrical member and the yoke, and power consumption when current is applied to attract the movable core to the fixed core can be reduced. In addition, the yoke member is provided with a push pin member that can be manually operated to move the movable core toward the fixed core, and the push pin member is provided on the convex portion so as to be freely movable in the axial direction and can be manually pressed in the axial direction from the outside. Therefore, since the flat surface of the yoke member from which the convex portion equipped with the push pin member protrudes is located axially inward from the cover member, the protruding dimension of the convex portion can be made smaller than in conventional electromagnets in which the end of the cylindrical member to which the stopper equipped with the push pin member is fixed protrudes farther in the axial direction than the end of the annular block, the protruding dimension of the convex portion can be made smaller, and the overall axial dimension can be made smaller.

[0009] In the invention described in claim 2, a convex portion protruding from the flat surface of the yoke member in the axial direction is provided, a through hole penetrating the convex portion is formed in the bottom surface of the cover member, a nut member is screwed onto the convex portion so as to be rotatable, and the bottom surface of the cover member is pressed against the flat surface of the yoke member by rotating the nut member. This allows the bottom surface of the cover member to be in close contact with the flat surface of the yoke member, thereby further reducing magnetic loss and power consumption. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a vertical sectional view showing an embodiment of the present invention in which an electromagnet is applied to a solenoid valve. [Diagram 2] FIG. 2 is an enlarged cross-sectional view taken along line AA in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An electromagnet according to an embodiment of the present invention applied to a solenoid valve will now be described with reference to the drawings. In FIG. 1, the solenoid valve is composed of a valve body 1, a first electromagnet 2 attached to one axial end of the valve body 1, a second electromagnet section 3 attached to the other axial end opposite the one axial end of the valve body 1, and a terminal box T placed on top of the valve body 1.

[0013] The valve body 1 is formed with a fitting hole 4 penetrating in the axial direction. The fitting hole 4 accommodates a spool 5 slidably in the axial direction. The inner peripheral surface of the fitting hole 4 is formed with an annular recess, with a supply passage P at approximately the center in the axial direction, load passages A and B spaced apart on both sides of the supply passage P in the axial direction, and a discharge passage R spaced apart on the axial outside of the load passages A and B. The supply passage P is connected to a pressure source of the fluid, the load passages A and B are connected to an actuator (not shown), and the discharge passage R is connected to the low pressure side. The spool 5 protrudes in an annular shape to form a land 6, which opens and closes each of the passages P, A, B, and R by moving in the axial direction, thereby switching and communicating between each of the passages P, A, B, and R. Springs 5A and 5B are arranged at both axial ends of the spool 5, and the spool 5 is held in a neutral position where the passages P, A, B, and R are blocked by the force of the springs 5A and 5B.

[0014] A cylindrical fixed core 7 of the first electromagnet 2 is screwed into one end opening of the fitting hole 4 that opens at one axial end of the valve body 1, and the first electromagnet 2 is attached and fixed to one axial end of the valve body 1. The other end opening of the fitting hole 4 that opens at the other axial end of the valve body 1 is 、 A second electromagnet 3 having the same configuration as the first electromagnet 2 is attached and fixed. Hereinafter, the first electromagnet 2 will be used as a representative example to explain electromagnets. 。

[0015] The first electromagnet 2 is composed of a cylindrical block 8, a coil block 9, a cover member 10, a spacer member 11, a nut member 12, and a washer member 13. The cylindrical block 8 is composed of a fixed core 7, a movable core 14, a yoke member 15, a cylindrical member 16, a rod member 17, and a push pin member 18. The coil block 9 is composed of a coil 19, a coil bobbin 20, and a molded resin 21.

[0016] The cylindrical block 8 is disposed opposite the side of the fixed core 7 screwed into the valve body 1, facing the yoke member 15, and the fixed core 7 and the yoke member 15 are fixed by welding with a cylindrical member 16 made of a non-magnetic material. The yoke member 15 is cylindrical and made of a magnetic material, and has an insertion hole 22 formed at one end facing the fixed core 7. The other end of the yoke member 15 opposite to the one end is formed as a flat surface H, and a protrusion 15A is formed protruding from the radial center of the flat surface H toward the axial outward direction. The movable core 14 is cylindrical and made of a magnetic material, and is inserted into the insertion hole 22 of the yoke member 15 so as to be slidable in the axial direction. As shown in FIG. 2, the circular cross-sectional area S1 of the yoke member 15 and the circular cross-sectional area S2 of the movable core 14 are formed to be approximately equal. The area of ​​the flat surface H of the yoke member 15 is set to be larger than the circular cross-sectional area S1 of the yoke member 15.

[0017] A flow hole 24 is formed axially through the movable core 14 at a position eccentric from the radial center, and the flow hole 24 allows fluid to flow freely between both ends of the movable core 14, thereby balancing the pressure between the two ends of the movable core 14. The rod member 17 is fitted into the radial center of the fixed core 7 so as to be slidable in the axial direction, and both axial ends abut against the spool 5 and the movable core 14, respectively, and pushes in the spool 5 as the movable core 14 is attracted to the fixed core 7. The push pin member 18 is fitted into the protrusion 15A of the yoke member 15 so as to be slidable in the axial direction, and can be manually pushed in axially from the outside by an operator using a tool such as a screwdriver, moving the movable core 14 toward the fixed core 7.

[0018] The coil block 9 is integrally formed by winding a coil 19 around an annular coil bobbin 20 and molding it with molding resin 21. The spacer member 11 is fitted onto the fixed core 7 and abuts against one axial end of the valve body 1. The coil block 9 is fitted onto the cylindrical block 8 and one axial end of the coil bobbin 20 abuts against the spacer member 11, while the other axial end of the coil bobbin 9 is flush with the flat surface H of the yoke member 15. The cover member 10 is approximately cup-shaped with a bottom surface K and made of a magnetic material, and has a through hole 25 formed at the radial center of the bottom surface K that penetrates in the axial direction.

[0019] Cover member 10 passes through convex portion 15A of yoke member 15 into through hole 25, and bottom surface K abuts against flat surface H of yoke member 15. Cover member 10 covers coil bobbin 9 and engages spacer member 11 at its open end. Washer member 13 fits over convex portion 15A of yoke member 15 and abuts against cover member 10. Nut member 12 screws onto convex portion 15A of yoke member 15, and is rotated to press cover member 10 against yoke member 15, with bottom surface K pressed against flat surface H. A magnetic circuit that generates an attractive force that attracts movable core 14 to fixed core 7 when current is applied to coil 19 is formed by movable core 14, fixed core 7, spacer member 11, cover member 10, and yoke member 15.

[0020] Next, the operation of this configuration will be described. 1 shows a state in which no current is applied to the coil 19, and the movable core 14 is stopped at a position separated axially to the right from the fixed core 7. The spool 5 is in a neutral position, blocking communication between the flow paths P, A, B, and R.

[0021] In this state, when electricity is applied to the coil 19, an attractive force is generated that attracts the movable core 14 to the fixed core 7, causing the movable core 14 to slide leftward in the figure and be attracted to the fixed core 7, and the rod member 17 presses the spool 5 leftward in the figure. The spool 5 slides leftward in the figure, switching and connecting the load flow path A to the supply flow path P, and switching and connecting the load flow path B to the discharge flow path R.

[0022] In this state, when the coil 19 is de-energized, the attractive force attracting the movable core 14 to the fixed core 7 disappears, and the spool 5 slides to the right in the figure by the force of the spring 5B and returns to the position shown in the figure, blocking the flow paths P, A, B, and R. The movable core 14 is pressed to the right in the figure by the rod member 17, and moves away from the fixed core 7 and returns to the position shown in the figure.

[0023] 1, when the second electromagnet 3 is energized, the spool 5 slides to the right in the figure, switching the load flow path A to communicate with the discharge flow path R, and switching the load flow path B to communicate with the supply flow path P. When the second electromagnet 3 is de-energized, the spool 5 slides to the left in the figure by the force of the spring 5A and returns to the position shown in the figure, blocking the flow paths P, A, B, and R.

[0024] In this operation, a yoke member 15 is provided having a fitting hole 22 into which the movable core 14 is fitted so as to be able to slide freely in the axial direction. The yoke member 15 is cylindrical and made of a magnetic material. One end where the fitting hole 22 opens is positioned opposite the fixed core 7, and the other end opposite the one end is formed into a flat surface H. The annular cross-sectional area S1 of the yoke member 15 and the circular cross-sectional area S2 of the movable core 14 are made to be approximately equal. The fixed core 7 and the yoke member 15 are fixed together with a cylindrical member 16 made of a non-magnetic material to form a cylindrical block 8. An annular coil bobbin 20 wound with a coil 19 is fitted onto the cylindrical block 8. The coil bobbin 20 is covered with a cover member 10 which is approximately cup-shaped and has a bottom surface K and is made of a magnetic material. The bottom surface K of the cover member 10 abuts against the flat surface H of the yoke member 15. As a result, the annular cross-sectional area S1 of yoke member 15 is made approximately equal to the cross-sectional area S2 of movable core 14, making it possible to increase the magnetic cross-section through which magnetic flux passes. Furthermore, since yoke member 15 and cover member 21, which form the magnetic circuit that generates the attractive force that attracts movable core 14 to fixed core 7, abut each other and have no gaps, magnetic loss can be reduced compared to conventional electromagnets in which a radial gap exists between the magnetic part of the cylindrical member and the yoke, and power consumption when current is applied to attract movable core 14 to fixed core 7 can be reduced.

[0025] Also, convex portion 15A protrudes in the axial direction from flat surface H of yoke member 15, and through-hole 25 is formed in bottom surface K of cover member 10, penetrating convex portion 15A, and nut member 12 is screwed into convex portion 15A so as to be rotatable, and bottom surface K of cover member 10 is pressed against flat surface H of yoke member 15 by rotating nut member 12. Therefore, bottom surface K of cover member 10 can be brought into intimate contact with flat surface H of yoke member 15, thereby further reducing magnetic loss and power consumption.

[0026] Furthermore, yoke member 15 is provided with push pin member 18 which manually moves movable core 14 towards fixed core 7, and push pin member 18 is provided on convex portion 15A so as to be freely movable in the axial direction and can be manually pushed in in the axial direction from the outside. Therefore, flat surface H of yoke member 15 from which convex portion 15A equipped with push pin member 18 protrudes is located axially inward from cover member 10, so that the protruding dimension of convex portion 15A can be made smaller and the overall axial dimension can be made smaller than in conventional electromagnets in which the end of a cylindrical member to which a stopper equipped with a push pin member is fixed protrudes farther in the axial direction than the end of an annular block.

[0027] In the embodiment described above, the cover member 10 is pressed against the yoke member 15 by the nut member 12, but a C-shaped retaining ring may be attached to the protrusion 15A of the yoke member 15 to press the cover member 10 against the yoke member 15. Also, the coil block 9, cover member 10, and spacer member 11 are each provided separately, but the coil block 9, cover member 10, and spacer member 11 may be provided integrally by crimping and fixing the spacer member 11 to the opening side end of the cover member 10 covering the coil block 9. Also, although the electromagnet is applied to a solenoid valve, it is of course possible to use it for other purposes. [Explanation of symbols]

[0028] 7: Fixed core 8: Cylindrical block 10: Cover material 14: Movable core 15: Yoke component 16: Cylinder part 19: Coil 20: Coil bobbin S1, S2: Cross-sectional area H: Flat surface K: Bottom

Claims

1. In an electromagnet in which a movable core is attracted to a fixed core by an attractive force generated by energizing a coil, the movable core is disposed opposite the fixed core, and a yoke member is provided having a fitting hole formed therein into which the movable core is fitted so as to be slidable in the axial direction. The yoke member is cylindrical and made of a magnetic material, and one end where the fitting hole opens is disposed opposite the fixed core, while the other end opposite the one end is formed as a flat surface. The yoke member is formed with an annular cross-sectional area substantially equal to the circular cross-sectional area of ​​the movable core, and the area of ​​the flat surface is set larger than the cross-sectional area of ​​the annular cross-sectional area, and the fixed core and yoke member are non-magnetic. and a cylindrical member made of a magnetic material is fixed to the cylindrical block to form a cylindrical block, an annular coil bobbin with a coil wound thereon is fitted onto the cylindrical block, a generally cup-shaped cover member made of a magnetic material having a bottom is provided to cover the coil bobbin, the bottom surface of the cover member abuts against a flat surface of a yoke member, the cover member has a convex portion protruding in the axial direction from the flat surface of the yoke member, the yoke member is provided with a push pin member that can be manually operated to move the movable core towards the fixed core, and the push pin member is attached to the convex portion so as to be freely movable in the axial direction and can be manually pressed in in the axial direction from the outside.

2. An electromagnet as described in claim 1, characterized in that a through hole penetrating the convex portion is formed in the bottom surface of the cover member, a nut member is screwed onto the convex portion so as to be freely rotatable, and the bottom surface of the cover member is pressed against the flat surface of the yoke member by rotating the nut member.

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