solenoid

Abstract

To provide a solenoid which seals a space providing a switch from liquid such as lubrication oil and water, and dust, and can sufficiently secure reliability of the switch.SOLUTION: A shaft 57 fixed to a plunger 80 presses up a pin 50, and the pin 50 makes a movable contact 61 separate from a fixing contact 62 by pressing up a plate spring 63 that supports the movable contact 61 of a switch 60. But since the pin 50 is inserted into a lower side packing 40 and an upper side packing 41, provided to a penetration hole 24, and an immersion such as lubrication oil or dew drop to a contact chamber 19 is prevented by the lower side packing 40 and the upper side packing 41. Also, since the pin 50 is linked with slide of the plunger 80 when the shaft 57 is contacted to the pin 50, a stroke of the pin 50 can be easily secured in a sufficient length.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a solenoid, and more particularly to a solenoid having a switch structure. [Background technology]

[0002] Solenoids used in vehicles and the like and having a switch structure usually have a structure for sealing the space where the switch is installed to prevent lubricating oil, water, etc. from entering the space where the switch is installed. Figure 10 is a cross-sectional view of a solenoid having a switch structure according to a conventional technology. In Figure 10, 100 denotes a solenoid, 110 denotes a contact assembly, 111 denotes a movable contact, 112 denotes a fixed contact, 113 denotes a movable contact, 114 denotes a fixed contact, 115 denotes a contact spring, 116 denotes a diaphragm, 117 denotes a terminal base, 118 denotes a housing recess, 119 denotes a yoke, 120 denotes a housing recess, 121 denotes a plunger, 122 denotes a connecting shaft, 123 denotes a housing, 124 denotes a coil bobbin, 125 denotes a coil, 126 denotes a return spring, 127 denotes a molded portion, and 128 denotes a communication hole.

[0003] FIG. 10 illustrates a solenoid disclosed in Japanese Patent Application Laid-Open Publication No. 2021-18957. The solenoid 100 includes a contact assembly 110, a terminal base 117, a yoke 119, a plunger 121, a coil bobbin 124, and other components arranged inside a case formed by a housing 123 and a molded section 127. A yoke 119 is provided between the coil bobbin 124 and the terminal base 117, and the yoke 119 vertically divides the interior of the case formed by the housing 123 and the molded section 127. The yoke 119 also includes an accommodating recess 120 that opens upward and a communication hole 128 that connects the interior of the coil bobbin 124 to the accommodating recess 120. A diaphragm 116 is provided in the accommodating recess 120. The periphery of the diaphragm 116 is sandwiched between the periphery of the accommodating recess 120 of the yoke 119 and the accommodating recess 120 of the yoke 119. Furthermore, when a current is applied to the coil 125 provided on the coil bobbin 124, the plunger 121 is attracted to the yoke 119 and rises together with the connecting shaft 122 connected to the plunger 121 until it pushes up the center of the diaphragm 116. When the current is stopped from being applied to the coil 125, the coil 125 is pushed downward by the elastic force of the return spring 126 and returns to its original position. In addition, the movable contacts 111 and 113 are provided in the contact assembly 110. Furthermore, the movable contacts 111 and 113 are in contact with the fixed contacts 112 and 114 when the coil 125 is not energized, because the contact assembly 110 is urged downward by the elastic force of the contact spring 115.

[0004] In the above configuration, when current is applied to the coil 125, the plunger 121 is attracted to the yoke 119 and rises, pushing up the center of the diaphragm 116 together with the connecting shaft 122 connected to the plunger 121. When the center of the diaphragm 116 is pushed up, the contact assembly 110 is also pushed up via the diaphragm 116, causing the movable contacts 111 and 113 to move away from the fixed contacts 112 and 114. When current is stopped from passing through the coil 125, the diaphragm 116 is pushed back downward by the elastic force of the return spring 126, and at the same time, the movable contacts 111 and 113 are urged downward by the elastic force of the contact spring 115, so that the movable contacts 111 and 113 once again come into contact with the fixed contacts 112 and 114. Therefore, the diaphragm 116 can be made smaller, and the fixed contacts 112 and 114 and the movable contacts 111 and 113 can be sealed against liquids such as lubricating oil.

[0005] In the above configuration, the vertical travel distance of the movable contacts 111 and 113, i.e., the stroke length, is significantly shorter than the stroke length of the plunger 121 due to the miniaturization of the diaphragm 116. The short stroke length of the movable contacts 111 and 113 affects the reliability of the fixed contacts 112 and 114 and the switch consisting of the movable contacts 111 and 113. By increasing the size of the diaphragm, the stroke length of the central portion can be increased, thereby improving the reliability of the switch. That is, the stroke length of the movable contacts 111 and 113 can be ensured to be sufficiently long and sufficiently separated from the fixed contacts 112 and 114. However, lead wires or coil wires connecting the coil 125 to the fixed contacts 112 and 114 or the wiring pattern must be routed around the diaphragm. Enlarging the diaphragm would require the diameter of the solenoid to be increased to secure space for this wiring, which is not a desirable solution. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-18957 Summary of the Invention [Problem to be solved by the invention]

[0007] In order to solve the above problems, the present invention aims to provide a solenoid having a configuration that can seal the space in which the switch is installed from liquids such as lubricating oil and water, and dust, while also fully ensuring the reliability of the switch. [Means for solving the problem]

[0008] The invention of claim 1 provides a switch including: a base having a through hole formed in its center and extending along a central axis; a contact chamber component arranged to be in contact with an upper surface of the base and having a through hole formed in its center that extends along the central axis and connects to the through hole of the base; a fixed contact fixed to the contact chamber component; a leaf spring having a base end fixed to the contact chamber component; a switch including a movable contact provided on the tip side of the leaf spring so as to face the fixed contact and be able to move toward and away from the fixed contact; a coil electrically connected to the switch; The solenoid has a pin configured to separate the movable contact from the fixed contact, a gasket formed in an approximately circular ring shape and provided inside the through hole of the base, with the pin inserted therethrough, and a plunger configured to be slidable along the central axis and to be attracted to the base when current is applied to the coil, wherein when current is applied to the coil, the plunger slides toward the base, causing the plunger or a shaft fixed to the plunger to push up the pin, and the pin pushes and bends the leaf spring of the switch, separating the movable contact from the fixed contact.

[0009] The invention described in claim 2 is the solenoid described in claim 1, characterized in that it further has another gasket formed in an approximately circular ring shape, located inside the through hole of the base and above the gasket, and through which the pin is inserted.

[0010] The invention described in claim 3 is a solenoid characterized in that, in the invention described in claim 2, it further has a spacer ring formed in an approximately circular ring shape, provided inside the through hole of the base, and arranged so as to be interposed between the gasket and the other gasket.

[0011] The invention described in claim 4 is a solenoid characterized in that, in the invention described in claim 3, it further has grease provided in the gap surrounded by the gasket, the other gasket, and the spacer ring.

[0012] The invention described in claim 5 is a solenoid characterized in that, in the invention described in any one of claims 2 to 4, the base is formed so that the inner diameter of the portion near the lower end of the through hole is smaller than the outer diameter of the gasket.

[0013] The invention described in claim 6 is a solenoid characterized in that, in the invention described in any one of claims 1 to 5, the pin has a main body portion that is approximately cylindrical and formed to extend along the central axis, and has a flange portion that protrudes in a direction perpendicular to the central axis near the middle portion in the direction of the central axis, and the base has a approximately circular recess formed in the center of the upper surface and with a diameter larger than the through hole, and is placed in the recess of the base, and is approximately annular plate-shaped and formed with an outer diameter larger than the through hole in the base and an inner diameter larger than the main body portion of the pin and smaller than the flange portion of the pin, and further includes a restraining plate inserted below the flange portion of the pin.

[0014] The invention described in claim 7 is a solenoid characterized in that, in the invention described in any one of claims 1 to 5, the pin has a main body that is approximately cylindrical and formed to extend along the central axis, and is provided with an E-type retaining ring fixed to a portion near the middle in the direction of the central axis, and the base has a approximately circular recess formed in the center of the top surface and a diameter larger than the through hole, and is placed in the recess of the base, is approximately annular plate-shaped, and has an outer diameter larger than the through hole of the base and an inner diameter larger than the main body of the pin and smaller than the E-type retaining ring of the pin, and is further provided with a retaining plate inserted below the E-type retaining ring of the pin. [Effects of the Invention]

[0015] According to the invention of claim 1, the plunger or the shaft fixed to the plunger pushes up the pin, which bends the leaf spring supporting the movable contact of the switch, separating the movable contact from the fixed contact, but because the pin is inserted into packings provided in the through holes of the base and the contact chamber component, the packings prevent the intrusion of lubricating oil, condensation, etc. into the contact chamber. Also, when the plunger or the shaft fixed to the plunger is in contact with the pin, the pin moves in conjunction with the sliding of the plunger, making it very easy to ensure the necessary and sufficient length of the pin stroke.

[0016] According to the invention as set forth in claim 2, by providing two packings, it is possible to more reliably prevent the intrusion of lubricating oil or the like into the contact chamber.

[0017] According to the invention as set forth in claim 3, it is possible to prevent the positions of the two packings from shifting due to repeated sliding of the pin.

[0018] According to the invention as set forth in claim 4, the grease can more reliably prevent lubricating oil or the like from entering the contact chamber.

[0019] According to the invention of claim 5, the inner diameter of the through hole near the lower end is smaller than the outer diameter of the packing, so that the packing can be prevented from falling out of the through hole due to repeated sliding of the pin.

[0020] According to the invention described in claim 6, the downward sliding of the pin can be restricted by the pressure plate, and the stroke of the pin can be easily adjusted to either lengthen or shorten by adjusting the thickness of the pressure plate.

[0021] According to the invention described in claim 7, the downward sliding of the pin can be restricted by the pressure plate, and the stroke of the pin can be easily adjusted to either lengthen or shorten by adjusting the thickness of the pressure plate. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a cross-sectional view of a solenoid according to a first embodiment of the present invention in a non-energized state. [Figure 2] 3 is a partially enlarged cross-sectional view of a pin and its surroundings in a non-energized state of the solenoid according to the first embodiment of the present invention. FIG. [Figure 3] 3 is a partially enlarged cross-sectional view of an upper main body portion of a pin and its periphery in a non-energized state of the solenoid according to the first embodiment of the present invention. FIG. [Figure 4] 1 is a cross-sectional view of a solenoid according to a first embodiment of the present invention in a current-carrying state. [Figure 5] 3 is a partially enlarged cross-sectional view of a pin and its periphery in a current-carrying state of the solenoid according to the first embodiment of the present invention. FIG. [Figure 6] 1 is a front view of a solenoid according to a first embodiment of the present invention in a non-energized state. [Figure 7] 1 is a plan view of a solenoid according to a first embodiment of the present invention in a non-energized state with a cover removed; [Figure 8] FIG. 10 is a partially enlarged cross-sectional view of a pin and its periphery in a non-energized state of a solenoid according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a partially enlarged cross-sectional view of a pin and its surroundings in a non-energized state of a solenoid according to a third embodiment of the present invention. [Figure 10] 1 is a cross-sectional view of a solenoid having a switch structure according to the prior art; DETAILED DESCRIPTION OF THE INVENTION

[0023] First, in the solenoid according to each embodiment of the present invention, the central axes of the base, contact chamber component, coil bobbin, attraction coil, holding coil, pin, plunger, and shaft are aligned. Therefore, in the following description of the solenoid according to each embodiment, the term "central axis" refers to the central axis common to all of these components. Furthermore, when the term "central axis" is used in the claims, it refers to the central axis common to the base, contact chamber component, plunger, and other components described in the claims. Furthermore, the orientation of the solenoid according to each embodiment of the present invention when actually installed in a diesel engine does not necessarily match the orientations shown in the drawings. Therefore, the terms "rising" and "falling," "upper" and "lower," and "upper" and "lower" in the following description are used for convenience in accordance with the layout of the drawings and may differ from the actual operating direction, etc., when actually installed.

[0024] Fig. 1 is a cross-sectional view of a solenoid according to a first embodiment of the present invention in a non-energized state. In Fig. 1, 10 is a solenoid, 19 is a contact chamber, 20 is a base, 22 is a fixing flange, 22a is an upper surface, 30 is a contact chamber component, 31 is a contact chamber base, 31a is a lower surface, 32 is a fixing portion, 33 is a cylindrical side wall, 46 is an auxiliary coil spring, 48 is a guide pipe, 49 is an O-ring, 50 is a pin, 56 is a return coil spring, 57 is a shaft, 58 is an upper end surface, 59 is a spacer, 60 is a switch, 61 is a movable contact, 62 is a fixed contact, 63 is a leaf spring, 65 is a The conductive and fixing member includes a fixing member 68, a coil bobbin 70, a winding drum 71, a first flange 72, a second flange 73, a third flange 74, a fourth flange 75, a notch 76a, a suction coil 77, a holding coil 78, a lid 79, a plunger 80, a through hole 81, a spring receiving recess 82, a case 83, a bottom plate 84, an opening 85, a small diameter cylindrical portion 86, a stepped portion 87, a large diameter cylindrical portion 88, and a bent portion 89. Fig. 2 is a partially enlarged cross-sectional view of the pin and its surroundings in the non-energized state of the solenoid according to the first embodiment of the present invention. In Fig. 2, 21 is a main body, 23 is an annular protrusion, 24 is a through hole, 25 is an inner peripheral surface, 29 is a spring seat, 40 is a lower packing, 41 is an upper packing, 42 is a spacer ring, 45 is a retaining plate, 47 is an O-ring, 51 is a lower main body, 52 is a lower end face, 54 is an upper main body, 55 is an upper end face, 64 is a conductive member, 76b is a notch, and other reference numerals indicate the same as in Fig. 1. Furthermore, Fig. 3 is a partially enlarged cross-sectional view of the upper main body of the pin and its surroundings in the non-energized state of the solenoid according to the first embodiment of the present invention. In Fig. 3, 26 is a bottom surface, 27 is a vertical surface, 28 is a recessed portion, 34 is a lower protrusion, 35 is an upper protrusion, 36 is a spring receiving portion, 36a is an inner peripheral surface, 37 is a large-diameter through-hole for storage, 38 is a small-diameter through-hole for storage, 39 is a stepped surface, and 53 is a flange portion, and other reference numerals indicate the same as those in Fig. 1. Fig. 6 is a front view of the solenoid according to the first embodiment of the present invention in a non-energized state. All reference numerals used in Fig. 6 indicate the same as those in Fig. 1. Fig. 7 is a plan view of the solenoid according to the first embodiment of the present invention in a non-energized state with the cover removed.In FIG. 7, 66a and 66b are coil wires, 67a and 67b are lead wires, 68a is a first fixing flange, 68b is a second fixing flange, 69a, 69b, 69c and 69d are through holes for wiring, and other symbols are the same as those in FIG.

[0025] First, an overview of a solenoid 10 according to a first embodiment of the present invention will be described. As shown in FIG. 6, the solenoid 10 has an appearance similar to a combination of cylinders of different diameters. As shown in FIG. 1, an outer shell is formed by a case 83, a contact chamber component 30, and a lid 79. The solenoid 10 is a direct-acting solenoid in which a plunger 80 moves linearly, and although not shown, is attached to a diesel engine body. Additionally, the case 83, base 20, and plunger 80 are all made of magnetic material and form a path for magnetic flux generated by energizing the attraction coil 77 and the holding coil 78. Furthermore, a switch 60 electrically connected to the attraction coil 77 is provided in the contact chamber 19, and as described below, turns the attraction coil 77 on or off in response to the elevation and lowering of the pin 50.

[0026] Next, the components of the solenoid 10 will be described in detail. As shown in FIG. 1 , the case 83 extends from a substantially circular bottom plate 84 disposed on the control rack side of a fuel supply pump of a diesel engine (not shown) toward the contact chamber 19 side. The following components are connected in this order: a substantially circular small-diameter cylindrical portion 86 connected to the bottom plate 84; a substantially circular stepped portion 87 connected to the small-diameter cylindrical portion 86; a substantially circular large-diameter cylindrical portion 88 having a larger diameter than the small-diameter cylindrical portion 86 and connected to the stepped portion 87; and a bent portion 89 connected to the large-diameter cylindrical portion 88 and used to secure the fixing flange 22 of the base 20. The bottom plate 84 has a substantially circular shape and is formed perpendicular to the central axis. A substantially circular opening 85 is formed in the center of the bottom plate 84, and the shaft 57 that operates the control rack is inserted through the opening 85. A spacer 59 is disposed inside the bottom plate 84 so as to contact the inside of the bottom plate 84. The guide pipe 48 is inserted inside the small diameter cylindrical portion 86. Furthermore, the fixing member 68 is press-fitted into the outer periphery of the small diameter cylindrical portion 86 at the end on the stepped portion 87 side. The coil bobbin 70 is disposed inside the large diameter cylindrical portion 88. The bent portion 89 is formed thinner than the large diameter cylindrical portion 88, and is a portion that is bent to cover the edge of the fixing flange portion 22 of the base 20, and serves to fix the base 20 to the case 83.

[0027] The coil bobbin 70 is made of resin and is disposed between the stepped portion 87 of the case 83 and the fixing flange portion 22 of the base 20. The coil wire wound in the gap between the first flange portion 72 and the second flange portion 73 of the winding drum portion 71 constitutes the attraction coil 77, and the coil wire wound in the gap between the second flange portion 73 and the third flange portion 74 constitutes the holding coil 78. The gap between the third flange portion 74 and the fourth flange portion 75 provides a space for connecting the ends of the coil wires constituting the attraction coil 77 and the holding coil 78 to lead wires (not shown). The notch portion 76a formed in the first flange portion 72 and the notch portion 76b formed on the base 20 side shown in FIG. 2 are provided with O-rings 49 and 47 to prevent the intrusion of lubricating oil and the like.

[0028] When energized, attraction coil 77, together with holding coil 78, generates a magnetic field that attracts plunger 80 toward base 20. Attraction coil 77 is also electrically connected to switch 60. When plunger 80 rises and pushes up pin 50, switch 60 turns off, de-energizing it. Holding coil 78 is provided to maintain plunger 80 in its raised position even after switch 60 turns off and de-energizing attraction coil 77. However, since holding coil 78 is energized simultaneously with attraction coil 77, it also serves as an auxiliary attraction coil. Spacer 59 is provided between bottom plate 84 and plunger 80 to prevent plunger 80 from adhering to bottom plate 84 of case 83, thereby preventing normal operation of solenoid 10 from being hindered. The guide pipe 48 serves to guide the sliding of the plunger 80, and is disposed inside the small diameter cylindrical portion 86 of the case 83 and the winding drum portion 71 of the coil bobbin .

[0029] The plunger 80 is formed in a generally cylindrical shape. The shaft 57 is inserted into a through-hole 81 extending along the central axis and is fixed by caulking. When the attraction coil 77 and the holding coil 78 are excited, the plunger 80 slides upward inside the guide pipe 48, and the upper end surface 58 abuts against the pin 50, further pushing the pin 50 upward. The lower portion of the return coil spring 56 is inserted into the spring receiving recess 82 of the plunger 80. As described above, the shaft 57 is fixed to the plunger 80 and moves up and down integrally with the plunger. A portion of the lower side of the shaft 57 constantly protrudes to the outside through an opening 85 of the case 83 to push against a control rack (not shown) and rotate the control pinion to the fuel cutoff side. The upper side of the shaft 57 protrudes upward from the spring receiving recess 82. The return coil spring 56 has its upper end abutting against the spring seat 29 of the base 20 shown in FIG. 2 and its lower end abutting against the bottom surface of the spring receiving recess 82 of the plunger 80, constantly exerting a resilient force that presses the plunger 80 downward against the bottom surface of the spring receiving recess 82. The fixing member 68 is used to attach the solenoid 10 to the diesel engine body (not shown), and is fixed to the diesel engine body by inserting bolts into openings in a first fixing flange 68a and a second fixing flange 68b shown in FIG. 7. Note that if the solenoid 10 is used for another purpose, for example, if it is not necessary to push the control rack, then the shaft may not be provided and the plunger may be configured to push up the pin 50.

[0030] The base 20 is a fixed magnetic pole that attracts the plunger 80, and as shown in FIG. 1, includes a main body 21 formed in a substantially cylindrical shape and a fixing flange 22 formed in a substantially disc shape. The main body 21 is formed in a short, substantially cylindrical shape extending along a central axis, with its base end integral with the fixing flange 22 and its tip end projecting downward. The main body 21 is inserted into the winding drum 71 of the coil bobbin 70, and a portion of its tip end is inserted into the guide pipe 48. Furthermore, as shown in FIG. 2, the main body 21 has a through hole 24 formed in its center and extending along the central axis. The through hole 24 provides a space for the pin 50 to move up and down, as well as a space for accommodating the lower packing 40, the upper packing 41, and the spacer ring 42. In addition, the through hole 24 has an annular protrusion 23 formed at its lower end such that the diameter of the inner circumferential surface 25 is smaller than the diameter of the lower packing 40, in order to prevent the lower packing 40 from moving downward as the pin 50 moves up and down and becoming detached toward the spacer ring 42. Also, as described above, the spring seat 29 that serves as a spring seat for the return coil spring 56 is formed on the underside of the main body 21. While the spring seat 29 is formed as a recess, it may alternatively be formed as a protrusion. The shape of this protrusion may be set as appropriate depending on the characteristics of the return coil spring 56.

[0031] The base 20 is also provided with the contact chamber component 30, with the upper surface 22a of the fixing flange 22 in contact with the lower surface 31a of the contact chamber base 31. This arrangement allows the through-hole 24 of the base 20 and the large-diameter storage through-hole 37 and small-diameter storage through-hole 38 of the contact chamber component 30 to form a space for the pin 50 to ascend and descend, as shown in FIG. 2 . Furthermore, a recess 28 is formed in the upper surface 22a of the fixing flange 22. Additionally, a disk-shaped retaining plate 45 is provided in the recess 28, sized to contact the bottom surface 26 and the vertical surface 27. As shown in FIG. 3 , the retaining plate 45 abuts against the flange 53 of the descending pin 50, thereby restricting the descending of the pin 50, i.e., defining the descending limit of the pin 50. The thickness of the retaining plate 45 can be adjusted to adjust the stroke length of the pin 50. As will be described later, if an E-type retaining ring is provided instead of the flange portion 53, the retaining plate 45 will come into contact with the E-type retaining ring of the descending pin 50, thereby restricting the descent of the pin 50.

[0032] The contact chamber component 30 is made of resin and, as shown in FIGS. 1 and 3 , includes a contact chamber base portion 31 that constitutes the contact chamber 19, a fixed portion 32 fixed to the large-diameter cylindrical portion 88 of the case 83, a cylindrical side wall portion 33 that receives the lid 79, a lower protrusion 34 that presses down on the retaining plate 45 to hold it in place, and an upper protrusion 35 and a spring receiving portion 36 that define spaces for storing the pin 50 and auxiliary coil spring 46. The contact chamber base portion 31 is formed in a generally circular plate shape and, as shown in FIG. 3 , is formed with a large-diameter storage through-hole 37 and a small-diameter storage through-hole 38 in its center, extending along the central axis. The fixed portion 32 is formed in a generally cylindrical shape so as to extend downward from the contact chamber base portion 31. The fixed portion 32 has a larger diameter than the large-diameter cylindrical portion 88 of the case 83, and is fixed with a portion of the upper side of the large-diameter cylindrical portion 88 inserted therein. The cylindrical side wall portion 33 is formed in a substantially cylindrical shape and extends upward from the contact chamber base portion 31. The cylindrical side wall portion 33 is formed thin near the upper end portion so that a step is formed on the inside, and is formed to engage with the lid 79.

[0033] The large-diameter storage through-hole 37 is formed across the contact chamber base portion 31 and the lower protrusion 34, and is formed with a diameter larger than the outer diameter of the flange portion 53 of the pin 50 to ensure space for the flange portion 53 to move up and down. The small-diameter storage through-hole 38 is formed across the contact chamber base portion 31 and the upper protrusion 35, and is formed with a diameter suitable for storing the upper main body portion 54 of the pin 50 and the auxiliary coil spring 46. Furthermore, the diameter of the large-diameter storage through-hole 38 is formed smaller than the diameter of the flange portion 53 to prevent the flange portion 53 of the pin 50 from slipping out into the small-diameter storage through-hole 38. The spring seat 36 is a spring seat for the upper end of the auxiliary coil spring 46, and the diameter of the inner circumferential surface 36a is formed smaller than the diameter of the auxiliary coil spring 46 to prevent the auxiliary coil spring 46 from slipping out upward. Step surface 39 between large-diameter storage through-hole 37 and small-diameter storage through-hole 38 abuts against flange portion 53 of rising pin 50, thereby restricting the rise of pin 50, that is, defining the limit of rise of pin 50. Also, instead of providing flange portion 53 on pin 50, an E-type retaining ring may be fixed to the portion of pin 50 that forms flange portion 53 in the direction of the central axis, i.e., the portion near the middle. Note that this E-type retaining ring must have a diameter that will not come off inside small-diameter storage through-hole 38.

[0034] As described above, the pin 50 is provided so as to move up and down within the storage space formed by the through-hole 24 of the base 20 and the large-diameter storage through-hole 37 and small-diameter storage through-hole 38 of the contact chamber component 30. That is, when the shaft 57 rises and the pin 50 is pushed up with the upper end surface 58 of the shaft 57 abutting against the lower end surface 52 of the pin 50, the leaf spring 63 abuts against the upper end surface 55, and the pin 50 further bends the leaf spring 63. The pin 50 also has a flange 53 provided between the lower main body portion 51 and the upper main body portion 54, which, as described above, serves to set the length of the ascending and descending stroke. The lower packing 40 and the upper packing 41 are airtight materials having a cross section that is, for example, approximately Y-shaped or approximately U-shaped, and both are provided to surround the lower main body portion 51 of the pin 50, and serve to seal the contact chamber 19 from liquids such as lubricating oil and water, as well as dust. Note that either or both of the lower packing 40 and the upper packing 41 may be an O-ring or a square ring, depending on conditions such as the diameter of the through hole 24.

[0035] As shown in FIG. 7 , the contact chamber 19 is provided with: a movable contact 61 and a fixed contact 62 of a switch 60 that turns the attraction coil 77 on or off; a leaf spring 63 that supports the movable contact 61 so that it can be raised and lowered and that forms part of the conductive path between the movable contact 61 and the attraction coil 77; a conductive member 64 that forms part of the conductive path between the fixed contact 62 and the attraction coil 77; a conductive and fixing member 65 that fixes the base end of the leaf spring 63 and that forms part of the conductive path between the leaf spring 63 and the attraction coil 77; wiring through holes 69a and 69c for introducing coil wires 66a and 66b, which are portions of the coil bobbin 70 near the ends, into the contact chamber 19; and wiring through holes 69b and 69d for leading the lead wires 67a and 67b out of the contact chamber 19. Incidentally, the wiring through-holes 69a, 69b, 69c, and 69d, which serve as paths for leading wires from the lead wire side to the contact chamber 19 side, penetrate not only through the contact chamber base portion 31 but also to the fixing flange portion 22 of the base 20. Also, as mentioned above, the large-diameter storage through-hole 37 and the small-diameter storage through-hole 38 are formed in the contact chamber base portion 31 of the contact chamber component 30, so that they basically communicate with the plunger 80 side, but the provision of the lower packing 40 and upper packing 41 prevents lubricating oil, condensation, and the like from penetrating into the contact chamber 19.

[0036] Next, an overview of the operation of the solenoid 10 according to the first embodiment of the present invention will be described. Figure 4 is a cross-sectional view of the solenoid according to the first embodiment of the present invention in a conducting state. All reference numerals used in Figure 4 represent the same elements as in Figure 1. Furthermore, Figure 5 is an enlarged cross-sectional view of a pin and its periphery in the solenoid according to the first embodiment of the present invention in a conducting state. All reference numerals used in Figure 5 represent the same elements as in Figure 1.

[0037] When the attraction coil 77 and the holding coil 78 are energized, a magnetic field is generated that attracts the plunger 80 toward the base 20. The plunger 80 rises toward the base 20, and as shown in FIG. 4, the upper end surface 58 of the shaft 57, which is integral with the plunger 80, abuts against the lower end surface 52 of the pin 50, further pushing the pin 50 upward. The pin 50 then stops when the plunger 80 abuts against the main body 21 of the base 20. As shown in FIG. 5, before the flange 53 abuts against the stepped surface 39, the upper end surface 55 of the pin 50 abuts against the leaf spring 63, bending the leaf spring 63. This separates the movable contact 61 from the fixed contact 62, turning the switch 60 off. When the switch 60 is turned off, the plunger 80 is held in its raised position toward the base 20 solely by the magnetic field generated by the holding coil 78. Although not shown, when shaft 57 rises, the control rack of the fuel pump moves to the fuel injection side, enabling the engine to operate. Therefore, the diesel engine remains operable while the holding coil 78 is energized.

[0038] Next, we will explain solenoids according to second and third embodiments of the present invention. Fig. 8 is a partially enlarged cross-sectional view of the pin and its periphery in a non-energized state of a solenoid according to the second embodiment of the present invention. In Fig. 8, 11 denotes the solenoid and grease 43, and other reference numerals are the same as those in Fig. 2. Furthermore, Fig. 9 is a partially enlarged cross-sectional view of the pin and its periphery in a non-energized state of a solenoid according to a third embodiment of the present invention. In Fig. 9, 12 denotes the solenoid, 44 denotes a single packing, 90 denotes a base, 91 denotes a main body, 92 denotes a fixing flange, 22a denotes an upper surface, 93 denotes an annular protrusion, 94 denotes a through hole, 95 denotes an inner peripheral surface, 96 denotes a bottom surface, 97 denotes a vertical surface, 98 denotes a recess, and 99 denotes a spring seat, and other reference numerals are the same as those in Fig. 2.

[0039] A solenoid 11 according to a second embodiment of the present invention has grease 43 injected into the gap surrounded by a lower packing 40, an upper packing 41, and a spacer ring 42. The other configurations are the same as those of the solenoid 10. This configuration allows the grease 43 to adhere to the peripheral surface of the lower body portion 51 of the pin 50, further improving sealing performance against liquids and dust. Furthermore, a solenoid 12 according to a third embodiment of the present invention, as shown in FIG. 9, has a single packing 44 with a substantially Y-shaped or U-shaped cross section instead of the lower packing 40, the upper packing 41, and the spacer ring 42. Furthermore, a through-hole 94 formed in the center of the body portion 91 of the base 90 is formed to an optimal length for accommodating the single packing 44 so that the single packing 44 does not shift out of position. That is, the diameter of the through hole 94 is larger in the direction of the central axis only in the region near the upper unitary packing 44 so that the inner peripheral surface 95 functions as a sliding guide surface for the pin 50, and the annular protrusion 93 is longer than the annular protrusion 23 of the base 20. Note that the recessed portion 98 consisting of the fixing flange portion 92, top surface 92a, bottom surface 96, and vertical surface 97 of the base 90, and the spring seat 99 have the same shapes as the recessed portion 28 consisting of the fixing flange portion 22, top surface 22a, bottom surface 26, and vertical surface 27 of the base 20, and the spring seat 29. The rest of the configuration is the same as that of the solenoid 10. The solenoid 12 has slightly inferior sealing performance against liquids and dust compared to the solenoid 10, but when the sealing performance of the unitary packing 44 alone is sufficient, for example, when the temperature change in the atmosphere of a diesel engine is small, this can be said to be a preferable embodiment from the perspective of reducing the manufacturing costs of the solenoid.

[0040] As described above, in the solenoids 10 to 12, the shaft 57 fixed to the plunger 80 pushes up the pin 50, which in turn pushes and bends the leaf spring 63 supporting the movable contact 61 of the switch 60, separating the movable contact 61 from the fixed contact 62. However, since the pin 50 is inserted through the lower and upper packings 40 and 41 or the individual packing 44 provided in the through hole 24, the lower and upper packings 40 and 41 or the individual packing 44 prevent lubricating oil, water, and the like from entering the contact chamber 19. Furthermore, when the shaft 57 is in contact with the pin 50, the pin 50 moves in conjunction with the sliding of the plunger 80, making it very easy to ensure a sufficient stroke length for the pin 50. Furthermore, since the holding coil 78 operates with a low current only required to hold the plunger 80 in the attracted position, the holding coil 78 can be operated safely even when continuously energized without burning out. Furthermore, in the solenoids 10 and 11, the provision of the lower packing 40 and the upper packing 41 more reliably prevents the intrusion of lubricating oil and the like into the contact chamber 19. Furthermore, in the solenoids 10 and 11, the provision of the spacer ring 42 can prevent the lower packing 40 or the upper packing 41 from shifting position due to repeated sliding of the pin 50. Furthermore, in the solenoid 11, the grease 43 can more reliably prevent the intrusion of lubricating oil and the like into the contact chamber 19. Furthermore, in the solenoids 10 to 12, the annular protrusion 23 is provided in the vicinity of the lower end of the through hole 24 of the base 20, so that the lower packing 40 and the upper packing 41, or the single packing 44, can be prevented from falling out of the through hole 24 due to repeated sliding of the pin 50. In addition, in the solenoids 10 to 12, the downward sliding of the pin 50 can be restricted by the retaining plate 45, and the stroke of the pin 50 can be easily adjusted to either lengthen or shorten by adjusting the thickness of the retaining plate 45.

[0041] The present invention is not limited to the above-described contents, and various configurations are possible as long as they do not deviate from the scope of the claims, such as, for example, having the upward protruding portion of the plunger push up the pin instead of having the shaft protruding outward push up the pin. [Explanation of symbols]

[0042] 10 Solenoid 11 Solenoid 12 Solenoid 19 Contact room 20 base 21 Main body 22 Fixing flange 22a Top side 23 Annular protrusion 24 through holes 25 Inner surface 26 bottom 27 Vertical plane 28 Depression 29 Spring seat 30 Contact chamber components 31 Contact chamber base 31a Bottom surface 32 Fixed part 33 Cylindrical side wall 34 Lower protrusion 35 Upper protrusion 36 Spring holder 36a Inner surface 37 Large diameter through hole for storage 38 Small diameter through hole for storage 39 Step surface 40 Lower packing 41 Upper packing 42 Spacer ring 43 Grease 44 Individual packing 45 Retaining plate 46 Auxiliary coil spring 47 O-ring 48 Guide pipe 49 O-ring 50 pin 51 Lower body part 52 Lower end face 53 Flange 54 Upper body part 55 Upper end face 56 Return coil spring 57 Shaft 58 Upper end surface 59 Spacer 60 Switch 61 Movable contact 62 Fixed contacts 63 Leaf spring 64 Conductive materials 65 Conductive and fixing member 66a coil wire 66b Coil Wire 67a lead wire 67b lead wire 68 Fixing member 68a First fixed guard 68b Second fixed guard 69a Wiring through hole 69b Wiring through hole 69c Wiring through hole 69d Wiring through hole 70 Coil bobbin 71 Winding body 72 First flange portion 73 Second flange 74 Third flange 75 Fourth flange 76a Notch 76b Notch 77 Suction Coil 78 Holding coil 79 Lid 80 Plunger 81 Through hole 82 Spring receiving recess 83 cases 84 Bottom plate part 85 Opening 86 Small diameter cylindrical part 87 Step 88 Large diameter cylindrical part 89 Bending section 90 base 91 Main body 92 Fixing flange 22a Top side 93 Annular protrusion 94 Through holes 95 Inner surface 96 bottom 97 Vertical plane 98 Depression 99 Spring seat 100 solenoid 110 Contact assembly 111 Movable contact 112 Fixed contacts 113 Movable contact 114 Fixed contacts 115 Contact spring 116 Diaphragm 117 Terminal Base 118 Storage recess 119 York 120 Receiving recess 121 Plunger 122 Connecting shaft 123 Housing 124 Coil bobbin 125 coil 126 Return spring 127 Mold section 128 Communication hole

Claims

1. a base having a through hole formed in the center thereof and extending along a central axis; a contact chamber component disposed in contact with an upper surface of the base, the contact chamber component having a through hole formed in the center thereof that extends along the central axis and communicates with the through hole of the base; a switch including a fixed contact fixed to the contact chamber component, a leaf spring having a base end fixed to the contact chamber component, and a movable contact provided on the tip side of the leaf spring so as to face the fixed contact and be capable of moving toward and away from the fixed contact; a coil electrically connected to the switch; a pin that is provided inside the through hole of the base and the through hole of the contact chamber component and that is slidable along the central axis, and that bends the leaf spring of the switch when raised to separate the movable contact from the fixed contact; a packing formed in a substantially annular shape, provided inside the through hole of the base, and having the pin inserted therethrough; a solenoid having a plunger that is slidably disposed along the central axis and that is attracted to the base when the coil is energized, When the coil is energized, the plunger slides toward the base, causing the plunger or a shaft fixed to the plunger to push up the pin, which then bends the leaf spring of the switch, separating the movable contact from the fixed contact.

2. 2. The solenoid according to claim 1, further comprising another gasket formed in a substantially annular shape, disposed inside the through hole of the base and above the gasket, and having the pin inserted therethrough.

3. 3. The solenoid according to claim 2, further comprising a spacer ring formed in a substantially annular shape, disposed inside the through hole of the base, and arranged so as to be interposed between the packing and the other packing.

4. 4. The solenoid according to claim 3, further comprising grease provided in a gap surrounded by the packing, the additional packing, and the spacer ring.

5. 5. The solenoid according to claim 2, wherein the base is formed so that the inner diameter of the through hole in the vicinity of the lower end thereof is smaller than the outer diameter of the packing.

6. The pin has a main body portion formed in a substantially cylindrical shape and extending along the central axis, and includes a flange portion protruding in a direction perpendicular to the central axis at a portion near a middle portion in the direction of the central axis, the base has a generally circular recessed portion formed in the center of the top surface, the recessed portion having a diameter larger than that of the through hole; The solenoid of any one of claims 1 to 5, further comprising a restraining plate that is disposed in the recessed portion of the base, is approximately annular, has an outer diameter larger than the through hole of the base, has an inner diameter larger than the main body of the pin, and is smaller than the flange portion of the pin, and is inserted below the flange portion of the pin.

7. the pin has a substantially cylindrical body portion formed to extend along the central axis, and includes an E-type retaining ring fixed to a portion near a middle portion in the direction of the central axis, the base has a generally circular recessed portion formed in the center of the top surface, the recessed portion having a diameter larger than that of the through hole; 6. The solenoid according to claim 1, further comprising a restraining plate that is disposed in the recessed portion of the base, is approximately annular, and has an outer diameter larger than the through hole of the base, an inner diameter larger than the main body of the pin, and is smaller than the E-type retaining ring of the pin, and is inserted below the E-type retaining ring of the pin.

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