JP2012160656A - Electromagnetic type drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic type drive unit enabling smooth sliding of a movable iron core without requiring a spacer.SOLUTION: A push rod 57 is installed integrally with a movable iron core 54 so that an end 57a thereof projects from an end face 54a of the movable iron core 54. A spring 58 disposed between the movable iron core 54 and an adjustment screw 40 has a spring force for forming a first clearance G which reduces an impact of an attraction force generated between the end face 54a of the movable iron core 54 and a bottomed portion 36a of a yoke 36 in magnetization, without any member interposed between the end face 54a of the movable iron core 54 and the bottomed portion 36a of the yoke 36 in the demagnetization state. In the demagnetization state, a second clearance F smaller than the first clearance G is formed between the end 57a of the push rod 57 and an end face 40a of the adjustment screw 40.

Description

  The present invention relates to an electromagnetic drive unit having a solenoid assembly.

  In this type of electromagnetic drive unit, the fixed iron core and the movable iron core are arranged coaxially, and the movable iron core contacts the fixed iron core by power supply control that varies the excitation force of the solenoid to the fixed iron core. It is configured to be separable.

  When a current is passed through the coil, the movable iron core is attracted to the fixed iron core by the exciting force. At this time, the movable iron core is attracted by the exciting force from the yoke bottom portion in the direction opposite to the fixed iron core, and a phenomenon occurs in which the movable iron core operates toward the yoke bottom portion side. At that time, the movable iron core may come into contact with the bottomed portion of the yoke, but at the time of contact, the inside is filled with oil, so that the phenomenon that the movable iron core sticks to the bottomed portion of the yoke occurs. To do.

  In this state where the movable iron core is attracted to the bottom side of the yoke, the movable iron core will operate normally if the exciting force acting on the fixed iron core side is weaker than the force that attracts the movable iron core to the bottom side of the yoke. The pressure is not reduced or increased in proportion to the current and cannot be controlled.

  When the force acting on the movable iron core is greater than the force attracting the movable iron core toward the bottom side of the yoke, the pressure is reduced or increased in proportion to the current. It becomes a controllable state.

  For this reason, conventionally, in Patent Document 1, in order to ensure the control state by reducing or increasing the pressure in proportion to the current, the force that the movable iron core is attracted to the fixed iron core side is A non-magnetic material with a certain thickness or more so that the suction force is greater than the force attracted to the yoke bottom side, and a spacer with an anti-adsorption groove made of oil on the end surface of the movable iron core is placed on the yoke bottom. In the demagnetized state, a configuration has been proposed in which the end surface of the movable iron core and the bottomed portion of the yoke are held at a predetermined interval.

JP 2006-336766 A

The conventional electromagnetic drive unit disclosed in Patent Document 1 described above has the following problems because it has a configuration in which a spacer is disposed between the end surface of the movable iron core and the bottomed portion of the yoke. .
(1) The spacer may be forgotten during assembly.
(2) Since the spacer is assembled in a deep place inside the yoke, the assembly workability is poor.
(3) The spacer has a groove for preventing adsorption by oil, and has a front surface and a back surface. Therefore, when assembling, it may be mistakenly assembled upside down, and if it is assembled in reverse, the maximum anti-adsorption effect cannot be obtained.
(4) As described above, the spacer has a groove for preventing adsorption due to oil, but in actual operation, adsorption occurs and causes performance deterioration.
(5) The spacer is not a standard one like JIS standard, it has a special shape, and since it has a barb for preventing pulling when assembled to a fixed iron core, it becomes expensive. It leads to cost increase.
(6) Since the shape of the bottom portion with the yoke for fitting the spacer is limited, it is necessary to process the bottom portion with the yoke.

  The present invention has been made from the above-described prior art, and an object thereof is to provide an electromagnetic drive unit capable of smoothly sliding a movable iron core without requiring a spacer.

  In order to achieve this object, the present invention provides a fixed iron core having a through hole along a central axis, a movable iron core arranged coaxially with the fixed iron core, and coaxial with the fixed iron core. A cylindrical yoke that encloses and cantilever the movable iron core and guides the movable iron core in a slidable manner, and surrounds the fixed iron core, the movable iron core, and the yoke. A solenoid assembly having a coil disposed, energizing and demagnetizing the fixed iron core by power supply control to the coil, and contacting and separating the movable iron core from the fixed iron core; and opposite to the fixed iron core An adjustment screw arranged so that the end surface thereof faces the end surface of the movable iron core located on the side, and the movable iron core is arranged between the end surface of the movable iron core and the end surface of the adjustment screw. A spring capable of biasing the core toward the fixed iron core In the obtained electromagnetic drive unit, a first projecting portion projecting from the end surface of the movable iron core toward the end surface of the adjustment screw and having a diameter smaller than the diameter of the movable iron core, and the adjustment screw At least one projecting portion of a second projecting portion that projects from the end surface toward the end surface of the movable iron core and that has a diameter smaller than the diameter of the adjusting screw. In the state, without any member being interposed between the end surface of the movable iron core and the bottomed portion of the yoke, the end surface of the movable iron core and the existence of the yoke are energized when the excitation is performed. A spring having a first clearance that reduces the influence of the attractive force generated between the bottom and the bottom, and in the demagnetized state, the end of the protrusion and the adjustment script Between the said end face of said end face side or the movable iron core is characterized by the formation of the small second clearance than the first clearance.

  The present invention configured as described above has an end face of the movable iron core that is energized by the spring force of the spring disposed between the end face of the movable iron core and the end face of the adjusting screw without any member interposed therebetween. Since the first clearance that reduces the influence of the attracting force generated between the arm and the bottom portion of the yoke can be formed, the movable iron core is reliably slid in the fixed iron core direction when excited from the demagnetized state. be able to.

  Further, in the demagnetized state, a second clearance smaller than the first clearance described above is provided between the end portion of the protruding portion and the end surface side of the adjustment screw or the end surface side of the movable iron core. At the time of demagnetization from the excited state, the end of the first projecting portion set to a diameter smaller than the diameter of the movable iron core contacts the end face of the adjustment screw, or the end face of the movable iron core is the adjustment screw. It abuts on the end of the second protrusion set to a diameter smaller than the diameter. As a result, the contact area at the time of contact can be reduced, and along with this, the occurrence of adsorption between the end surface side of the movable iron core and the end surface side of the adjusting screw can be prevented. The first clearance can be reliably formed between the end surface of the core and the bottomed portion of the yoke.

  That is, the present invention is generated between the end surface of the movable iron core and the bottomed portion of the yoke in the demagnetized state as described above, and between the end surface of the movable iron core and the bottomed portion of the yoke by the spring force of the spring. Forming a first clearance that reduces the influence of the attracting force, and between at least one of the first protrusion and the second protrusion and the end face side of the adjustment screw or the end face side of the movable iron core. Since the second clearance smaller than the first clearance is formed, the movable iron core can be smoothly slid without requiring a spacer. Therefore, all the problems associated with providing the spacer can be eliminated.

  Further, the present invention is the above invention, comprising: a through hole formed coaxially with a central axis of the movable iron core; and a push rod press-fitted into the through hole and provided integrally with the movable iron core, However, the end portion of the push rod that protrudes from the end surface of the movable iron core toward the end surface of the adjustment screw and can be prevented from moving by the end surface of the adjustment screw when demagnetized from the excited state. It is characterized by comprising.

  Further, the present invention is the above invention, wherein the projecting portion is formed integrally with the adjustment screw and projects in the end face direction of the movable iron core, and when the magnet is demagnetized from the excited state, It consists of the convex part which can prevent the movement to the said adjustment screw direction of the said end surface.

  According to the present invention, in the above invention, the spring comprises a single compression coil spring set in a shape surrounding the protruding portion.

  The present invention projects from the end face of the movable iron core toward the end face of the adjustment screw, and has a first projecting portion set to a diameter smaller than the diameter of the movable iron core, and the end face direction of the movable iron core from the end face of the adjustment screw. The spring disposed between the end face of the movable iron core and the end face of the adjustment screw is provided with at least one protrusion of the second protrusion set to a diameter smaller than the diameter of the adjustment screw. In the magnetic state, without any interposition between the end surface of the movable iron core and the bottomed portion of the yoke, pulling that occurs between the end surface of the movable iron core and the bottomed portion of the yoke when energized. It has a spring force that forms a first clearance that reduces the influence of the attaching force, is in a demagnetized state, and is formed between the end portion of the projecting portion and the end surface side of the adjusting screw or the end surface side of the movable iron core. In between, smaller than the first clearance It is to form the structure of the 2 clearance. Thereby, a movable iron core can be slid smoothly, without requiring a spacer. Therefore, it is possible to eliminate all the problems associated with providing the spacers that have occurred in the past.

  That is, it is possible to reduce assembly man-hours and processing man-hours as compared with the conventional case, and to reduce the manufacturing cost of the electromagnetic drive unit. In addition, the number of parts can be reduced, which can also reduce the manufacturing cost. Furthermore, since the occurrence of adsorption between the end face of the movable iron core and the bottomed portion of the yoke can be prevented, the sliding performance of the movable iron core can be improved as compared with the conventional case.

It is a longitudinal cross-sectional view which shows the solenoid valve provided with the electromagnetic drive unit which concerns on 1st Embodiment of this invention, Comprising: The A side is the state at the time of non-power feeding to a solenoid, The B side is the state at the time of power feeding to a solenoid FIG. It is a principal part enlarged view of FIG. It is a principal part enlarged view of the electromagnetic drive unit which concerns on 2nd Embodiment of this invention.

  Embodiments of an electromagnetic drive unit according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing a solenoid valve provided with an electromagnetic drive unit according to the first embodiment of the present invention. The A side shows a state when no power is supplied to the solenoid, and the B side shows power supply to the solenoid. FIG. 2 is a main part enlarged view of FIG.

  The electromagnetic valve 10 is used for various controls, and is suitable for, for example, mini-excavator cab interference prevention / depth control, hydraulic piston / motor tilt angle control, control valve spool / throttle valve control, and the like. Further, the electromagnetic valve 10 includes a direction control valve unit 11 and an electromagnetic drive unit 12 according to the present embodiment that is mechanically connected to one end side and operates the direction control valve unit 11.

  The electromagnetic drive unit 12 includes a disk-shaped solenoid base 14 (hereinafter referred to as a base 14). The base 14 includes an end wall 15 that connects the directional control valve unit 11 to the outer surface thereof, and a fixed iron core 16 that is formed integrally with a central portion of the end wall 15. The fixed iron core 16 is formed to project from the end wall 15 in a columnar shape in the direction opposite to the direction control valve unit 11. A through hole 18 is formed coaxially in the center of the fixed iron core 16, and the through hole 18 extends in the axial direction thereof, and is opened at the outer surface of the end wall 15, that is, the outer end surface and the inner end surface 16 a of the fixed iron core 16. is doing.

  The fixed iron core 16 includes an annular protruding edge 19 that integrally protrudes in the axial direction from the peripheral edge of the inner end surface 16a. The annular projecting edge 19 is mainly formed to improve the magnetic properties, and the outer diameter gradually decreases toward the tip, while the inner diameter is configured to be constant along the axial direction of the fixed iron core 16. . In other words, the tip outer shape of the annular projecting edge 19 forms a truncated cone shape, while the inner end surface 16a and the inner peripheral surface of the annular projecting edge 19 form a cylindrical hollow portion. Thus, the annular projecting edge 19 has a function as a guide for the movable iron core 54 described later. A bush rod 57 is press-fitted into a through hole 110 formed coaxially with the central axis of the movable iron core 54 so that the movable iron core 54 and the push rod 54 are integrated.

  The yoke 36 has a bottomed portion 36 a, has a smaller diameter than the outer peripheral case 35, is press-fitted and coupled coaxially with the outer peripheral case 35, and further has a cylindrical shape coaxial with the fixed iron core 16 to the fixed iron core 16 side. It extends, opens at one end side 36c, and forms a concentric hole 36b therein.

An adjusting screw 40 is screwed onto the yoke 36 so as to close the concentric hole 36b. Specifically, the adjustment screw 40 partially protrudes from the yoke 36 while being screwed to the yoke 36, and a lock nut 41 is screwed to the protruding part and is fixed to the yoke 36. And the end surface 40a which opposes the push rod 57 toward the concentric hole 36b is formed in the front-end | tip of the adjustment screw 40. As shown in FIG. The material of the adjustment screw 40 is made of a non-magnetic material so as not to be affected by excitation. The material is not particularly limited as long as it is a non-magnetic material, and examples thereof include SUS304 and copper.

  Between the end surface 54a of the movable iron core 54 and the end surface 40a of the adjustment screw 40, a spring 58 is arranged that can urge the movable iron core 54 in the direction of the fixed iron core 16. The adjustment screw 40 presses the movable iron core 54 via a spring 58 to adjust the thrust of the solenoid. The inside of the yoke 36 is closed by an O-ring 31 attached to the adjustment screw 40.

  A cylindrical solenoid assembly 21 for energizing the fixed iron core 16 is accommodated between the outer case 35 and the yoke 36 so as to be coaxial with the outer case 35 and the yoke 36. The solenoid assembly 21 includes a bobbin 22 and a coil 24 wound around the bobbin 22.

  The bobbin 22 has a stepped inner peripheral surface and is fitted on the yoke 36 and the fixed iron core 16. A 0-ring 33 is disposed on the inner diameter stepped portion of the bobbin 22 that is externally fitted to the yoke 36 and the fixed iron core 16.

  Specifically, one end of the solenoid assembly 21 is accommodated in a cylindrical space defined by the outer peripheral surface of the fixed iron core 16, the end wall 15, and the inner peripheral surface of the outer peripheral case 35. More specifically, the one end is in contact with the end wall 15, an annular recess is formed on the contact surface, and an O-ring 32 is disposed in the recess.

A part of the solenoid assembly 21 is provided with a peripheral wall 48 a surrounding the connection terminal 46 in an exposed state, and the peripheral wall 48 a constitutes a male plug 48 together with the connection terminal 46. Thus, if the male plug 48 and a female plug (not shown) are inserted into each other, power can be supplied to the coil 24 from the outside. Further, as shown in FIG. 1, an accommodation chamber is formed above the inner end surface 16a of the fixed iron core 16 and is composed of a hollow portion in the annular projecting edge 19, a hollow portion in the small diameter portion 22a of the bobbin 22, and a concentric hole 36a. In this accommodation chamber, a cylindrical movable iron core 54 is accommodated coaxially with the fixed iron core 16. Specifically, the outer peripheral surface of the movable iron core 54 is coated with a resin layer 55 having a uniform thickness, and the other end side of the movable iron core 54 that is separated from the fixed iron core 16 is connected to the yoke 36 via the resin layer 55. It is cantilevered and is configured to be slidable in the axial direction within the yoke concentric hole 36b.

  The resin layer 55 is made of a nylon resin, and the thickness thereof is set in a range of, for example, 0.01 mm or more and less than 0.1 mm. The resin layer 55 can be formed by a known method, and a detailed description of the processing method is omitted here, but the material is not limited to the above.

  As shown in FIG. 2, the electromagnetic drive unit 12 according to the present embodiment projects from the end surface 54 a of the movable iron core 54 toward the end surface 40 a of the adjustment screw 40, and has a diameter smaller than the diameter of the movable iron core 54. At least one of the set first protrusion and the second protrusion that protrudes from the end face 40a of the adjustment screw 40 toward the end face 54a of the movable iron core 54 and has a diameter smaller than the diameter of the adjustment screw 40. The projection is provided. For example, the push rod 57 is protruded from the end surface 54a of the movable iron core 54, and the protruding end portion 57a constitutes the first protruding portion. The diameter of the push rod 57 is set to 3 mm or less, for example.

  The above-described spring 58 is in a demagnetized state, and without any member interposed between the end surface 54a of the movable iron core 54 and the bottomed portion 36a of the yoke 36, the end surface of the movable iron core 54 is energized when excited. 54a and a bottomed portion 36a of the yoke 36, and has a spring force that forms a first clearance G that reduces the influence of an attracting force generated. The spring 58 is disposed so as to surround the end portion 57a of the push rod 57, and is composed of, for example, one compression coil spring.

  Further, the electromagnetic drive unit 12 according to the present embodiment is in a demagnetized state, and is between the end portion of the protruding portion and the end surface 40a side of the adjustment screw 40 or the end surface 54a side of the movable iron core 54. In addition, the second clearance F, which is a clearance smaller than the first clearance G described above, is provided. For example, as shown on the A side in FIG. 2, the second clearance F is provided between the end portion 57 a of the push rod 57 and the end surface 40 a of the adjustment screw 40.

  The direction control valve unit 11 is connected to the above-described electromagnetic drive unit 12 by coupling a sleeve-shaped valve casing 62 to the base 14. Specifically, a peripheral wall 64 extends from the end wall 15 of the base 14, and the peripheral wall 64 has a female screw portion 65 on its inner peripheral surface, while the valve casing 62 is an outer peripheral surface facing the peripheral wall 64. The valve casing 62 is directly connected to the base 14 by screwing the male screw portion 66 of the valve casing 62 into the female screw portion 65.

  Thus, in the valve casing 62, the end portion on the male screw portion 66 side is closed by the end wall 15, while the opposite end portion of the male screw portion 66 is closed by the end plate 68. Inside the valve casing 62, a supply chamber 72, an output chamber 74, and a drain chamber 76 are formed in order from the end wall 15 side to the end plate 68 side, and valves that partition these chambers 72, 74, 76 are formed. Small diameter sealing surfaces 78, 80, and 82 are formed on the inner peripheral surface of the casing 62. The valve casing 62 includes three ports that open on the outer peripheral surface thereof, that is, a supply port 84, an output port 86, and a drain port 88. The three ports are a supply chamber 72 and an output chamber 74, respectively. , And a corresponding one of the drain chambers 76.

  A valve spool 83 is coaxially accommodated inside the valve casing 62, and the valve spool 83 is accommodated via a return spring 90 so as to be slidable in the axial direction. The tip of the push rod 57 is in contact with the end surface of the valve spool 83 on the end wall 15 side, and the valve spool 83 is mechanically connected to the movable iron core 54 via the push rod 57. The valve spool 83 has two land portions 92 and 94 that are separated from each other in the axial direction at an intermediate portion near the output port 86. Of these, the outer peripheral surface of the land portion 92 is formed on the valve casing 62 when the valve spool 83 is on the end wall 15 side in the valve casing 62 (discharge position) as shown on the A side in FIG. It is possible to seal between the supply chamber 72 and the output chamber 74 in cooperation with the sealing surface 80. Further, as shown on the B side in FIG. 1, the outer peripheral surface of the other land portion 94 is moved to the end plate 68 side in the valve casing 62 against the urging force of the return spring 90 in the valve casing 62. Sometimes (supply position) it is possible to seal between the output chamber 74 and the drain chamber 76 in cooperation with the sealing surface 82 of the valve casing 62.

  The valve casing 62 is surrounded by a case (not shown) including flow paths separately connected to the three ports 84, 86, 88, and an O-ring externally fitted to the valve casing 62 is provided between these flow paths. 96, 98.

  Hereinafter, the operation of the above-described electromagnetic valve 10 and the operation of the present invention will be described.

  In operating the solenoid valve 10, first, the solenoid valve 10 is connected to a power source. This power supply may be either a DC power supply or an AC power supply. For example, DC12V or DC24V can be used as the DC power supply, and AC100V (50/60 Hz) or AC200V can be used as the AC power supply.

  When power is not supplied to the coil 24, that is, at the discharge position shown on the A side in FIG. 1, the movable iron core 54 is urged toward the adjustment screw 40 by the return spring 90 via the push rod 57. It is in. When the power supply to the coil 24 is instantaneously cut, the movable iron core 54 is pushed back toward the adjusting screw 40 by the force of the return spring 90, but is pushed back to a predetermined position or more by the inertial force. At this time, the end surface 40a of the adjustment screw 40 and the end portion 57a of the push rod 57 are in contact with each other, so that the adjustment screw 40 serves as a stopper. When power is supplied from the power source to the coil 24 via the connection terminal 46, a magnetic field (excitation force) is generated by the coil 24, the fixed iron core 16 is excited, and the movable iron core 54 is fixed with an attractive force corresponding to the amount of current. It is sucked into the iron core 16. Thus, the outer peripheral surface of the movable iron core 54 is guided to the yoke 36 through the resin layer 55 and is displaced toward the fixed iron core 16.

  Incidentally, as described above, a clearance is provided between the movable iron core 54 and the annular projecting edge 19 so that the excitation lateral component force acting on the movable iron core 54 does not change greatly. Even if the iron core 54 slides and approaches the annular projecting edge 19, a large excitation lateral component force does not act on the movable iron core 54. In this way, when a large excitation lateral component force does not act on the movable iron core 54, normally, the annular protruding edge 19 is hardly excited uniformly over the entire circumference. This tendency tends to be biased toward the side where the excitation lateral component force is strong, and this tendency becomes more prominent as the excitation lateral component force increases. However, such a bias of the movable iron core 54 is prevented, and the movable iron core 54 While being held coaxially with the fixed iron core 16, it slides smoothly in the yoke 36 without uneven contact.

  Thereby, the nonmagnetic resin layer 55 applied to the movable iron core 54 can be well protected without uneven wear.

  When the movable iron core 54 is displaced toward the fixed iron core 16 in this way, the displacement of the movable iron core 54 is transmitted to the valve spool 83 via the push rod 57, the return spring 90 is compressed, and the valve spool 83 is Move to supply position.

  When the valve spool 83 is in the supply position shown on the B side in FIG. 1, the hydraulic oil at this time passes from the supply port 84 connected to the pump through the valve casing 62 to the actuator connected to the output port 86. Flowing. When power supply to the coil 24 is stopped, the magnetic field generated by the coil 24 disappears, the fixed iron core 16 is demagnetized, and the valve spool 83 is moved to the discharge position by the extension force of the compressed return spring 90 to be movable. The iron core 54 moves away from the fixed iron core 16 and returns to the inoperative position.

  Accordingly, the valve spool 83 is in the discharge position shown on the A side in FIG. 1, and the hydraulic oil at this time passes through the valve casing 62 from the output port 86 connected to the actuator, and the tank connected to the drain port 88. It flows toward.

  In the present embodiment, when the movable iron core 54 is energized without any intervention by the spring force of the spring 58 disposed between the end face 54a of the movable iron core 54 and the end face 40a of the adjusting screw 40, Since the first clearance G that reduces the influence of the attracting force generated between the end face 54a and the bottomed portion 36a of the yoke 36 can be formed, the movable iron core 54 is fixed to the fixed iron core 16 when excited from the demagnetized state. It can be reliably slid in the direction.

  Further, a second clearance F smaller than the first clearance G is provided between the end 57a of the push rod 57 that forms the first projecting portion in the demagnetized state and the end surface 40a of the adjustment screw 40. Thus, when demagnetizing from the excited state, the end portion 57 a of the push rod 57 set to a diameter smaller than the diameter of the movable iron core 54 comes into contact with the end surface 40 a of the adjustment screw 40. Thereby, the contact area at the time of contact can be reduced, and the occurrence of adsorption between the end surface 54a of the movable iron core 54 and the end surface 40a of the adjustment screw 40 can be prevented. The first clearance G can be reliably formed between the end surface 54 a and the end surface 40 a of the adjustment screw 40.

  That is, in the present embodiment, the first clearance G is formed by the spring force of the spring 58 between the end surface 54a of the movable iron core 54 and the bottomed portion 36a of the yoke 36 in the demagnetized state as described above. Since the second clearance F smaller than the first clearance G is formed between the end 57a of the push rod 57 and the end surface 40a of the adjustment screw 40, the movable iron core 54 is smoothly slid without requiring a spacer. Can be moved.

  Therefore, the present invention can eliminate all the problems associated with providing the spacer. That is, the assembly man-hours and processing man-hours can be reduced as compared with the case where the spacer is provided, and the production cost of the electromagnetic drive unit 12 can be reduced. In addition, the number of parts can be reduced, which can also reduce the manufacturing cost. Furthermore, since the occurrence of adsorption between the end surface 54a of the movable iron core 54 and the bottomed portion 36a of the yoke 36 can be prevented, the sliding performance of the movable iron core 54 can be improved.

  FIG. 3 is an enlarged view of a main part of an electromagnetic drive unit according to the second embodiment of the present invention.

  As shown in FIG. 3, the second embodiment projects from the end surface 40 a of the adjustment screw 40 toward the end surface 54 a of the movable iron core 54, and is set to a diameter smaller than the diameter of the adjustment screw 40, for example, about 3 mm. The second protrusion is provided. The second protrusion is formed integrally with the end surface 40a of the adjustment screw 40 and protrudes in the direction of the end surface 54a of the movable iron core 54. When the magnet is demagnetized from the excited state, the second protrusion is in the direction of the adjustment screw 40. It consists of the convex part 40b which can prevent the movement to to by the edge part 40b1.

  In the second embodiment, a through hole is not provided in the central axis of the movable iron core 54, but a bottomed hole is formed in place of such a through hole, although not shown. A bush rod (not shown) having a shorter length than that in the first embodiment is press-fitted into the hole with a bottom (not shown), and the push rod and the movable iron core 54 are integrated by this press-fitting.

  The spring 58 in the second embodiment is also in a demagnetized state, and is excited when no member is interposed between the end surface 54a of the movable iron core 54 and the bottomed portion 36a of the yoke 36. It has a spring force that forms a first clearance G that reduces the influence of the attractive force generated between the end surface 54a of the movable iron core 54 and the bottomed portion 36a of the yoke 36. Further, the spring 58 is composed of one compression coil spring disposed so as to surround the convex portion 40 b provided on the end surface 40 a of the adjustment screw 40.

  The second embodiment is also in a demagnetized state, and the first clearance G is between the end 40b1 of the convex portion 40b provided on the end surface 40a of the adjustment screw 40 and the end surface 54a of the movable iron core 54. The second clearance F, which is a smaller clearance, is provided. Other configurations are the same as those of the first embodiment described above.

  Similarly to the first embodiment, the second embodiment configured as described above is in a demagnetized state and is formed between the end surface 54a of the movable iron core 54 and the bottomed portion 36a of the yoke 36. A first clearance G, a second clearance F formed between the end 40 b 1 of the convex portion 40 b provided on the end surface 40 a of the adjustment screw 40 and the end surface 54 a of the movable iron core 54 and having a smaller clearance than the first clearance G. Therefore, the same effects as those of the first embodiment described above can be obtained.

  In the first and second embodiments described above, if the dimension of the second clearance F is set too small, the movable range of the valve spool 83 of the direction control valve unit 11, that is, the control range becomes narrow, and the electromagnetic valve 10 performance deterioration will be caused. Therefore, it is necessary to set the dimension of the second clearance F to a dimension that can ensure a good control range.

  In the first embodiment described above, the end 57a of the push rod 57 protruding from the end surface 54a of the movable iron core 54 is provided as the first protruding portion protruding from the end surface 54a of the movable iron core 54, and the second embodiment. Then, although it is set as the structure which provided the convex part 40b integrally formed in the adjustment screw 40 as a 2nd protrusion part which protrudes from the end surface 40a of the adjustment screw 40, both the 1st protrusion part and the 2nd protrusion part are provided. The second clearance F may be formed between the end of the first protrusion and the end of the second protrusion.

DESCRIPTION OF SYMBOLS 10 Solenoid valve 11 Direction control valve unit 12 Electromagnetic drive unit 16 Fixed iron core 21 Solenoid assembly 24 Coil 36 Yoke 36a Bottomed part 40 Adjustment screw 40a End surface 40b Convex part (2nd protrusion part)
54 Movable iron core 54a End face 57 Push rod 57a End (first protrusion)
58 Spring 111 Through-hole F Second clearance G First clearance

Claims (4)

A fixed iron core having a through hole along the central axis;
A movable iron core disposed coaxially with respect to the fixed iron core;
A cylindrical yoke that is arranged coaxially with respect to the fixed iron core, encloses and cantilever the movable iron core, and slidably guides the movable iron core;
A coil disposed so as to surround the fixed iron core, the movable iron core, and the yoke; the fixed iron core is excited and demagnetized by power supply control to the coil; A solenoid assembly that contacts and separates from the fixed iron core;
An adjustment screw arranged so that the end face of the movable iron core is opposite to the end face of the movable iron core,
An electromagnetic drive unit comprising a spring disposed between the end face of the movable iron core and the end face of the adjustment screw, and capable of biasing the movable iron core in the fixed iron core direction.
A first projecting portion that projects from the end surface of the movable iron core toward the end surface of the adjustment screw and has a diameter smaller than the diameter of the movable iron core, and the movable iron from the end surface of the adjustment screw. Projecting in the end face direction of the core, and providing at least one projecting portion of the second projecting portion set to a diameter smaller than the diameter of the adjusting screw;
The spring is in the demagnetized state and does not interpose any member between the end surface of the movable iron core and the bottomed portion of the yoke, and when the magnetism is excited, Comprising a spring force that forms a first clearance that reduces the influence of the attractive force generated between the end surface and the bottomed portion of the yoke;
In the demagnetized state, a second clearance smaller than the first clearance is formed between the end portion of the protruding portion and the end surface side of the adjustment screw or the end surface side of the movable iron core. An electromagnetic drive unit characterized by that. The electromagnetic drive unit according to claim 1,
A through hole formed coaxially with the central axis of the movable iron core, and a push rod press-fitted into the through hole and provided integrally with the movable iron core,
The push rod that protrudes from the end face of the movable iron core toward the end face of the adjustment screw and can be prevented from moving by the end face of the adjustment screw when demagnetized from the excited state. An electromagnetic drive unit comprising: The electromagnetic drive unit according to claim 1,
The protruding portion is formed integrally with the adjustment screw and protrudes toward the end face of the movable iron core. When the protrusion is demagnetized from the excited state, the end face of the movable iron core toward the adjustment screw is formed. An electromagnetic drive unit comprising a convex portion capable of preventing movement. The electromagnetic drive unit according to any one of claims 1 to 3,
The electromagnetic drive unit according to claim 1, wherein the spring comprises one compression coil spring set in a shape surrounding the protrusion.

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