JP5475982B2 - solenoid - Google Patents

Description

  The present invention relates to a solenoid that moves a shaft in an axial direction by a magnetic field generated in a coil.

  Conventionally, for example, in the case of a solenoid attached to a mother machine such as a hydraulic device, hydraulic fluid guided from the mother machine to the solenoid includes contamination made of wear powder generated in the mother machine. If this contamination accumulates in the strong magnetic field part of the solenoid, the solenoid thrust may be weakened, the sliding resistance during shaft movement may increase, and the solenoid may malfunction.

  In each of the solenoids disclosed in Patent Documents 1 and 2, a plunger is slidably provided between a base constituting a magnetic circuit and a sleeve, and the plunger is driven by a magnetic field generated in the coil and coupled to the plunger. The shaft is moved in the axial direction to drive the valve body.

  The solenoid disclosed in Patent Document 1 is provided with an annular member (contamination block 71) for slidably fitting the shaft, and hydraulic oil flowing from the mother machine is blocked by the annular member (contamination block 71) to the outside. It escapes and it is comprised so that the hydraulic fluid containing a contamination may not flow into a plunger accommodating chamber.

The solenoid disclosed in Patent Document 2 is provided with an annular filter (ring filter 11) for slidably fitting a shaft, and a chamber (contamination reservoir 12) for collecting contaminants in the vicinity of the filter. Contamination of the flowing hydraulic oil is configured not to enter the plunger accommodating chamber.
JP 2006-64076 A Japanese Patent Laid-Open No. 11-31617

  However, in such a conventional solenoid, since an annular member (contamination block 71) and a filter (ring filter 11) for slidably fitting the shaft are provided, the sliding resistance of the shaft is increased. There was a problem that the responsiveness of the solenoid deteriorated.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a solenoid that can both suppress the influence of contamination and improve the operation responsiveness.

The present invention is a solenoid that drives a mother machine by driving a plunger by a magnetic field generated in a coil and moving a shaft coupled to the plunger in an axial direction, and slidably supports the shaft with the plunger interposed therebetween. A first bearing and a second bearing; a plunger front chamber defined between the first bearing and the plunger; a plunger back chamber defined between the plunger and the second bearing; a plunger front chamber and a plunger; A plunger outer circumferential path communicating with the back chamber and a cylindrical cover made of a non-magnetic material surrounding the plunger outer circumferential surface, the plunger outer circumferential path including an annular gap defined around the cover, and a plunger outer circumferential path and a groove formed on the surface, the cover has a collar-shaped front cover surrounding the plunger front end surface of the plunger so as not to block the groove, the plunger front surface Exposed from the front cover portion, it has an inner peripheral exposed portion of the annular defining contamination reservoir to collect the contamination on the inner peripheral side of the plunger front chamber, the working fluid of the mother machine plunger front chamber and the plunger outer peripheral passage and the plunger behind The configuration led to the chamber.

  According to the present invention, since the outer peripheral surface of the plunger is wrapped by the cylindrical cover made of a non-magnetic material, the contamination is not directly attracted to the outer peripheral surface of the plunger facing the strong magnetic field portion, and the contamination is accumulated around the plunger. Can be suppressed.

  Since the plunger outer circumferential path is defined as an annular gap around the cover, the flow path cross-sectional area is sufficiently ensured, so that the plunger moves by reducing the viscous resistance of the hydraulic oil applied to the plunger. Increase speed. When the plunger moves at a high speed, the operation responsiveness of the solenoid can be improved, and contamination accumulated on the plunger can be removed, thereby preventing malfunction of the solenoid due to contamination of the hydraulic oil.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a front view of the solenoid 1, and FIG. 2 is a cross-sectional view taken along line A-O-A in FIG.

  The solenoid 1 is an electromagnetic actuator that drives the plunger 4 by a magnetic field generated in the coil 12 and moves the shaft 5 coupled to the plunger 4 in the axial direction.

  The solenoid 1 is attached to a mother machine of a hydraulic device (not shown). The end 52 of the shaft 5 is linked to a hydraulic valve provided in the mother machine, and opens and closes the hydraulic valve.

  Not limited to this, the solenoid 1 may be provided in a pneumatic device, other machine, or facility, and may drive a pneumatic valve or other movable part.

  The solenoid 1 includes a case 9, a base 2, a sleeve 3, a plunger 4, a shaft 5, a gap embedded body 6, first and second bearings 7 and 8, a pair of O-rings 19, a coil assembly 10, and the like as components. .

  The coil assembly 10 includes a cylindrical bobbin 11 having flanges at both ends, a coil 12 formed by winding a magnet wire around the bobbin 11, and a pair of terminals coupled to both ends of the magnet wire of the coil 12. 13 and a mold resin 14 surrounding the coil 12.

  The mold resin 14 includes a cylindrical enclosure 16 in which the bobbin 11 and the coil 12 are accommodated, and a connector 15 that protrudes from one end of the enclosure 16 and faces the terminal 13. A mating connector (not shown) is inserted into the connector portion 15. When the coil 12 is energized through the mating connector, a magnetic field is generated around the coil 12. Not limited to this, the coil 12 may be energized via a lead wire.

  As a magnetic path constituting member for guiding the magnetic flux of the coil 12, a case 9, a base 2, a plunger 4, and a sleeve 3 are provided, which are each formed of a magnetic material.

  1 and 2, O is the center line of the shaft 5. A cylindrical plunger 4 is fitted to the outer periphery of the shaft 5 and coupled by welding or caulking.

  The case 9 is formed in a bottomed cylindrical shape and has a pair of flange portions 91 protruding from the opening end portion thereof. Bolt holes 98 are opened in each flange portion 91 and are fastened to the mounting seat of the mother machine by two bolts (not shown) that pass through the respective bolt holes 98.

  A coil assembly 10 is accommodated inside the case 9. A notch 97 opening on the side surface of the case 9 is formed, and the connector 15 projects from the notch 97.

  In FIG. 1, each flange portion 91 protrudes in the left-right direction so as to be orthogonal to the center line O, and the connector portion 15 protrudes upward so as to be orthogonal to the center line O.

  Not only this but the direction which the flange part 91 and the connector part 15 protrude is arbitrarily arrange | positioned corresponding to the shape of the other party to which the solenoid 1 is attached. For example, the connector part 15 may be protruded in the center line O direction, and the mating connector may be inserted / removed in the center line O direction.

  The cylindrical base 2 and the sleeve 3 are arranged on the inner side of the case 9 and coaxially with the center line O, and the shaft 5 and the plunger 4 are inserted into the inner sides thereof. The base 2 is disposed on the opening end side of the case 9, and the sleeve 3 is disposed on the back side of the case 9.

  The sleeve 3 has an outer peripheral surface 31 fitted into the inner peripheral surface of the bobbin 11, an end surface 32 abutting against the bottom surface 93 of the case 9, and is arranged coaxially with the center line O of the shaft 5.

  The outer peripheral surface 25 of the base 2 is fitted to the inner peripheral surface of the bobbin 11 and is disposed coaxially with the center line O of the shaft 5.

  A disc-shaped base collar 21 is formed at one end of the base 2, and the base collar 21 is coupled to the open end of the case 9. Also by this, the case 9 is arranged coaxially with the center line O of the shaft 5.

  An annular step 92 is formed at the open end of the case 9. The annular step portion 92 is formed in a planar shape orthogonal to the center line O, and constitutes a seating surface for the base 2. The end surface 22 of the base flange 21 abuts on the annular step 92 of the case 9, and the outer peripheral surface 23 of the base flange 21 is fitted to the inner peripheral surface 94 of the case 9.

  An annular step 24 is formed on the outer peripheral surface of the base flange 21. A caulking portion 95 is formed at the opening end of the case 9, and the caulking portion 95 is engaged with the annular step portion 24, thereby preventing the base 2 from coming off.

  The end surface 96 of the case 9 abuts against a mounting seat of a counterpart mother machine (not shown).

  The shaft 5 is made of a nonmagnetic material, passes through the sleeve 3 and the base 2, and is supported so as to be slidable in the direction of the center line O via the first and second bearings 7 and 8. The plunger 4 is disposed between the first and second bearings 7 and 8.

  The sleeve 3 has a small-diameter sleeve inner peripheral surface 33 and a large-diameter sleeve inner peripheral surface 34 on its inner periphery.

  The outer peripheral surface 81 of the second bearing 8 is fitted and attached to the inner peripheral surface 33 of the small diameter sleeve.

  An annular gap 55 is formed between the inner peripheral surface 34 of the large diameter sleeve and the outer peripheral surface 41 of the plunger.

  The base 2 has base inner peripheral surfaces 26 to 29 that gradually increase in diameter on the inner periphery thereof.

  The base inner peripheral surface 26 having the smallest diameter defines a gap 56 between the base outer peripheral surface 51 and the outer peripheral surface 51 of the shaft 5.

  The outer peripheral surface 71 of the first bearing 7 is fitted and attached to the base inner peripheral surface 27 having the second smallest diameter.

  An annular gap 55 is formed between the base inner peripheral surface 29 having the largest diameter and the plunger outer peripheral surface 41.

  FIG. 3 is an enlarged cross-sectional view around the plunger 4. As also shown, an annular step 46 is formed between the base inner peripheral surface 28 and the base inner peripheral surface 29 in the base 2. The annular step 46 is formed in a planar shape orthogonal to the center line O of the shaft 5 and faces the plunger front end surface 47 in parallel.

  The base 2 has an annular tapered end surface 45 that is inclined with respect to the center line O of the shaft 5. On the other hand, the sleeve 3 has an annular end surface 35 orthogonal to the center line O of the shaft 5. An annular magnetic gap is formed between the annular tapered end surface 45 of the base 2 and the annular end surface 35 of the shaft 5. The annular end face 35 may be inclined without being orthogonal to the center line O.

  The magnetic flux generated inside the coil 12 is guided by the case 9, the base 2, the plunger 4, and the sleeve 3. Since the magnetic flux passing between the base 2 and the sleeve 3 is blocked by the magnetic gap, the magnetic flux is guided through the plunger 4 to ensure the magnetic flux from the base 2 toward the plunger 4.

  The shape and position of the magnetic gap are arbitrarily set, and a solenoid thrust force corresponding to a stroke in which the plunger 4 moves in the direction of the center line O is obtained.

  A gap buried body 6 made of a nonmagnetic material is interposed in the magnetic gap. The gap embedded body 6 abuts on the annular tapered end surface 45 of the base 2 and the annular end surface 35 of the sleeve 3 without any gap, and forms a seal that seals these abutting portions. Then, the end surface 32 of the sleeve 3 abuts against the bottom surface 93 of the case 9 without a gap, thereby forming a seal that seals the abutting portion. The base 2, the gap embedded body 6, the sleeve 3, and the case 9 constitute a pressure vessel that accommodates the plunger 4 and the shaft 5. Thereby, the working oil (working fluid) flowing into the solenoid 1 from the mother machine is prevented from leaking out of the solenoid 1.

  In the coil assembly 10, O-rings 19 are interposed at both ends of the bobbin 11. One O-ring 19 is in contact with the base flange 21, and the other O-ring 19 is in contact with the bottom surface 93 of the case 9. The base 2, the coil assembly 10 (bobbin 11), and the case 9 constitute a pressure vessel that houses the plunger 4 and the shaft 5. This also prevents the hydraulic oil flowing into the solenoid 1 from the mother machine from leaking out of the solenoid 1.

  The gap embedded body 6 may not be interposed between the annular tapered end surface 45 of the base 2 and the annular end surface 35 of the sleeve 3, and a gap may be formed.

  The solenoid 1 is provided with a first bearing front chamber 73, a plunger front chamber 74, a plunger back chamber 75, and a second bearing back chamber 76 around the shaft 5 and the plunger 4, and hydraulic oil from the mother machine is guided to these. .

  The first bearing front chamber 73 is provided in front of the first bearing 7 and is defined between the base 2 and the first bearing 7. The first bearing front chamber 73 communicates with the mother machine side through a gap 56 defined between the shaft 5 and the base 2, and hydraulic oil from the mother machine is guided. This gap 56 constitutes a base through passage 62 that communicates the mother machine with the first bearing front chamber 73.

  The base inner peripheral surface 26 may be increased in diameter so that contamination can be accumulated in the base through passage 62.

  The plunger front chamber 74 is defined between the first bearing 7 and the plunger front end surface 47.

  The first bearing 7 is interposed between the first bearing front chamber 73 and the plunger front chamber 74. The first bearing 7 does not have a flow path penetrating the first bearing 7 and functions to block communication between the first bearing front chamber 73 and the plunger front chamber 74.

  The plunger back chamber 75 is defined between the end surface 48 of the plunger 4 and the second bearing 8.

  The plunger 4 is interposed between the plunger front chamber 74 and the plunger back chamber 75. In order to prevent the magnetic adsorption between the sleeve 3 and the plunger 4, an annular gap 55 is defined around the plunger outer peripheral surface 41. The annular gap 55 constitutes a plunger outer circumferential path 63 that communicates the plunger front chamber 74 and the plunger back chamber 75.

  A plurality of grooves 42 are formed in the plunger outer peripheral surface 41 as the plunger outer peripheral path 63. The hydraulic oil is configured to flow between the plunger front chamber 74 and the plunger back chamber 75 through the grooves 42.

  By defining the plunger outer circumferential path 63 by the plurality of grooves 42, the clearance of the gap 55 can be reduced. By reducing the clearance of the gap 55, the magnetic efficiency for driving the plunger 4 can be increased.

  A cylindrical cover 83 made of a non-magnetic material surrounding the plunger outer peripheral surface 41 is provided. An annular gap 55 is defined around the cover 83. The annular gap 55 constitutes a plunger outer circumferential path 63 that communicates the plunger front chamber 74 and the plunger back chamber 75.

  By covering the plunger outer peripheral surface 41 with the cover 83 made of a nonmagnetic material, it is possible to suppress the accumulation of contamination on the plunger outer peripheral surface 41.

  When the flow path cross-sectional area of the plunger outer circumferential path 63 is sufficiently secured, the flow of the hydraulic oil around the plunger 4 is promoted when the plunger 4 moves, and the viscous resistance of the hydraulic oil applied to the plunger 4 is reduced. Thus, the operation response of the solenoid 1 can be enhanced. Thus, when the plunger 4 moves at a high speed, the contamination accumulated on the cover 83 is removed.

  The cover 83 includes a cylindrical outer cover portion 84 that wraps around the plunger outer peripheral surface 41, and a bowl-shaped front end cover portion 85 that faces the plunger front end surface 47.

  The front end cover portion 85 is formed in a bowl shape orthogonal to the inner diameter direction from the front end of the outer peripheral cover portion 84, and faces the plunger front end surface 47 with a gap 40. By providing this gap 40, the plunger outer peripheral path 63 defined by the groove 42 of the plunger 4 is not blocked.

  The plunger front end surface 47 has an annular outer peripheral portion 47 a covered with the front end cover portion 85 and an annular inner peripheral exposed portion 47 b not covered with the front end cover portion 85. The inner peripheral exposed portion 47 b is opposed to the inner diameter portion of the base suction surface 46 of the base 2, and defines a space in the inner peripheral portion of the plunger front chamber 74 as a contamination reservoir portion 79.

  The second bearing back chamber 76 is provided behind the second bearing 8, and is defined between the second bearing 8 and the bottom surface 93 of the case 9.

  The second bearing 8 is interposed between the plunger back chamber 75 and the second bearing back chamber 76. A plurality of grooves 82 are formed on the outer peripheral surface 81 of the second bearing 8. These grooves 82 constitute a second bearing through passage 64 that allows the plunger back chamber 75 and the second bearing back chamber 76 to communicate with each other.

  A vertical through hole 53 that penetrates the shaft 5 in the direction of the center line O and a horizontal through hole 54 that penetrates the shaft 5 in the radial direction perpendicular to the center line O are formed. The vertical through hole 53 and the horizontal through hole 54 constitute a shaft through path 65 that communicates the mother machine with the second bearing rear chamber 76.

  By connecting a hydraulic valve (not shown) of the mother machine to an end 52 protruding from the base 2 of the shaft 5, the open end of the vertical through hole 53 is closed. In that case, the shaft end passage 65 is prevented from being blocked by the open end of the lateral through hole 54 communicating with the mother machine.

  Next, the operation of the embodiment of the present invention configured as described above will be described.

  When the solenoid 1 is assembled to the mother machine and the hydraulic oil (not shown) of the mother machine is filled with hydraulic oil, the hydraulic oil from the mother machine is filled into the solenoid 1 through the following path.

  The hydraulic oil from the mother machine is filled into the first bearing front chamber 73 through the base through passage 62 (gap 56).

  The hydraulic oil from the mother machine is filled into the second bearing rear chamber 76 through the shaft through passage 65 (the horizontal through hole 54 and the vertical through hole 53).

  The hydraulic oil in the second bearing back chamber 76 is filled into the plunger back chamber 75 through the second bearing through passage 64 (groove 82).

  The hydraulic oil in the plunger back chamber 75 is filled into the plunger front chamber 74 through the plunger outer peripheral path 63 (gap 55, groove 42).

  The solenoid 1 drives the plunger 4 by the magnetic force of the coil 12, moves the shaft 5 coupled to the plunger 4 in the axial direction, and drives the hydraulic valve of the mother machine to open and close.

  When the coil 12 is not energized, the shaft 5 is held at the initial position by the reaction force received from the hydraulic valve of the mother machine.

  When the coil 12 is energized, the plunger 4 is driven toward the base 2 by the solenoid thrust generated by the magnetic field generated inside the coil 12, and the shaft 5 is moved forward (to the left in FIG. 2). Open / close drive. FIG. 2 shows an operating state in which the shaft 5 is moved by a certain stroke from the initial position by the solenoid thrust.

  When the shaft 5 moves forward, the volume of hydraulic oil from which the shaft 5 retreats from the second bearing back chamber 76 flows into the second bearing back chamber 76 from the mother machine through the shaft through passage 65.

  At this time, when the plunger 4 moves forward, hydraulic oil corresponding to the moving volume of the plunger 4 flows from the plunger front chamber 74 that contracts into the plunger back chamber 75 that extends through the plunger outer circumferential path 63.

  When the energization of the coil 12 is stopped, the shaft 5 moves rearward (to the right in FIG. 2) by the reaction force received from the hydraulic valve of the mother machine, and opens and closes the hydraulic valve of the mother machine.

  When the shaft 5 moves rearward, the volume of hydraulic oil into which the shaft 5 enters the second bearing back chamber 76 flows out from the second bearing back chamber 76 through the shaft through passage 65 to the mother machine.

  At this time, when the plunger 4 moves rearward, the hydraulic oil corresponding to the moving volume of the plunger 4 flows from the plunger back chamber 75 that contracts into the plunger front chamber 74 that extends through the plunger outer peripheral path 63.

  By the way, the hydraulic fluid led from the mother machine to the solenoid 1 includes contaminations such as wear powder generated in the mother machine. Among these contaminants, magnetic iron powder or the like enters the strong magnetic field B where the magnetic flux concentrates between the base 2 and the end of the plunger 4 when entering the plunger front chamber 74 and the plunger back chamber 75 of the solenoid 1. get together. When many contaminants adhere to the surface of the magnetic material (base 2 and plunger 4) constituting the strong magnetic field part B, the following problems occur.

  The magnetic flux density of the strong magnetic field portion B where the magnetic flux concentrates changes, and the characteristics of the solenoid 1 change.

  -The sliding resistance of the plunger 4 increases or the stroke range in which the plunger 4 slides is narrowed.

  In response to this, the communication between the first bearing front chamber 73 and the plunger front chamber 74 is blocked by the first bearing 7, and the hydraulic fluid of the mother machine passes through the shaft through passage 65, the second bearing rear chamber 76, and the second bearing. The configuration is such that the plunger is guided to the plunger back chamber 75 through the passage 64. As a result, the path for the contamination of the hydraulic oil to reach the strong magnetic field portion B around the plunger 4 is lengthened, and the contamination adheres to the surface of the magnetic material (base 2, plunger 4) constituting the strong magnetic field portion B, and accumulates. Can be suppressed. Thereby, the malfunction of the solenoid 1 resulting from the contamination of hydraulic oil can be prevented, and the movable time during which the solenoid 1 operates stably can be extended.

  In addition, the second bearing back chamber 76 that is expanded and contracted by the movement of the shaft 5 communicates with the plunger back chamber 75 via the second bearing through passage 64, so that the pressure fluctuation from the mother machine is subject to the second bearing back chamber 76. , The pressure fluctuation in the second bearing back chamber 76 is transmitted to the plunger back chamber 75 through the second bearing through passage 64, and the second bearing 8 has a pressure difference between the second bearing back chamber 76 and the plunger back chamber 75. Can be prevented from falling off.

  Since the plunger outer peripheral surface 41 is wrapped by the cylindrical cover 83 made of a non-magnetic material, the contamination is not directly attracted to the plunger outer peripheral surface 41 facing the strong magnetic field portion B, and the contamination is accumulated around the plunger 4. Can be suppressed.

  Since the outer peripheral portion 47a of the plunger front end surface 47 is covered by the bowl-shaped front end cover portion 85, contamination is prevented from accumulating on the outer peripheral portion 47a of the plunger front end surface 47 facing the strong magnetic field portion B, and the solenoid 1 is stabilized. The operating time can be extended.

  Since the plunger front end surface 47 has an annular inner peripheral exposed portion 47b that is not covered by the front end cover portion 85, contamination is attracted to the inner peripheral exposed portion 47b of the plunger 4 that is out of the strong magnetic field portion B, and the influence on the solenoid thrust is small. Contamination is collected in the contamination reservoir 79 defined in the inner peripheral portion of the plunger front chamber 74, and the movable time during which the solenoid 1 operates stably can be extended.

  As the plunger outer peripheral path 63 is provided with an annular gap 55 defined around the cover 83, the hydraulic oil around the plunger 4 is moved when the plunger 4 moves by ensuring a sufficient cross-sectional area of the flow path. , The viscosity resistance of the hydraulic oil applied to the plunger 4 is reduced, and the operation responsiveness of the solenoid 1 in which the plunger 4 moves by the magnetic force can be enhanced. Further, when the plunger 4 moves at a high speed, the contamination attached to the cover 83 is removed. Thereby, the malfunctioning of the solenoid 1 resulting from the contamination of hydraulic fluid can be prevented.

  Since the plunger outer circumferential path 63 includes a plurality of grooves 42 formed on the plunger outer circumferential surface 41, the flow path cross-sectional area of the plunger outer circumferential path 63 is expanded by these grooves 42. Thereby, when the plunger 4 moves, the flow of the hydraulic oil around the plunger 4 is promoted, the viscosity resistance of the hydraulic oil applied to the plunger 4 is reduced, and the operation responsiveness of the solenoid 1 can be improved.

  As described above, in the present embodiment, the plunger 4 is driven by the magnetic field generated in the coil 12 and the shaft 5 coupled to the plunger 4 is moved in the axial direction to drive the mother machine. The first bearing 7 and the second bearing 8 that slidably support the plunger 5 with the plunger 4 interposed therebetween, the plunger front chamber 74 defined between the first bearing 7 and the plunger 4, the plunger 4 and the second bearing A plunger rear chamber 75 defined between the bearing 8, a plunger outer circumferential path 63 communicating with the plunger front chamber 74 and the plunger rear chamber 75, and a cylindrical shape made of a non-magnetic material surrounding the plunger outer circumferential surface 41. A cover 83, and a plunger outer peripheral path 63 is defined as an annular gap 55 around the cover 83. And configured to be guided to the Nja behind chamber 75.

  Based on the above configuration, since the plunger outer peripheral surface 41 is wrapped by the cylindrical cover 83 made of a nonmagnetic material, contamination is not directly attracted to the plunger outer peripheral surface 41 facing the strong magnetic field portion B, and the plunger 4 It is possible to suppress the accumulation of contamination around.

  Since the plunger outer circumferential path 63 is defined as an annular gap 55 around the cover 83 to sufficiently secure the flow path cross-sectional area, by reducing the viscous resistance of the hydraulic oil applied to the plunger 4, The speed at which the plunger 4 moves can be increased. When the plunger 4 moves at a high speed, the operation responsiveness of the solenoid 1 can be improved, and contamination accumulated on the plunger 4 can be removed, thereby preventing malfunction of the solenoid 1 due to contamination of the hydraulic oil.

  In the present embodiment, the cover 83 has a configuration having a bowl-shaped front end cover portion 85 that covers the plunger front end surface 47.

  Based on the above configuration, the front end cover portion 85 of the cover 83 made of a non-magnetic material can prevent contamination from being accumulated on the plunger front end surface 47, and the movable time during which the solenoid 1 operates stably can be extended.

  In the present embodiment, the plunger front end surface 47 has an annular inner peripheral exposed portion 47 b that is not covered by the front end cover portion 85.

  Based on the above configuration, contamination is attracted to the inner peripheral exposed portion 47b of the plunger 4, and the contaminant is collected in the inner peripheral space (contamination reservoir portion 79) of the plunger front chamber 74 that has little influence on the solenoid thrust. The operating time for stable operation can be extended.

  In the present embodiment, a shaft through passage 65 that passes through the shaft 5 in the axial direction and communicates the mother machine and the second bearing back chamber 76, and a plunger back chamber 75 and the second bearing back through the second bearing 8. A second bearing through passage 64 that communicates with the chamber 76, the first bearing 7 blocks communication between the mother machine side (base through passage 62) and the plunger front chamber 74, and the working fluid of the mother machine passes through the shaft through passage 65. The second bearing back chamber 76 and the second bearing through passage 64 are guided to the plunger back chamber 75.

  Based on the above configuration, the length of the path for the hydraulic oil contamination to reach the strong magnetic field B around the plunger 4 is lengthened and adheres to the surface of the magnetic material (base 2, plunger 4) constituting the strong magnetic field B. Can be suppressed. Thereby, the movable time during which the solenoid 1 operates stably can be extended.

  Since the second bearing back chamber 76 expanded and contracted by the movement of the shaft 5 communicates with the plunger back chamber 75 via the second bearing through passage 64, the pressure fluctuation from the mother machine is transmitted to the second bearing back chamber 76. However, the pressure fluctuation in the second bearing back chamber 76 is transmitted to the plunger back chamber 75 through the second bearing through passage 64, and the second bearing 8 falls off due to the pressure difference between the second bearing back chamber 76 and the plunger back chamber 75. Can be prevented.

  Next, another embodiment shown in FIG. 4 will be described. This has basically the same configuration as the embodiment of FIGS. 1 to 3, and only the differences will be described. In addition, the same code | symbol is attached | subjected to the same structure part as the said embodiment.

  The shaft 5 has a solid structure with the shaft through passage 65 (the horizontal through hole 54 and the vertical through hole 53) eliminated.

  A plurality of grooves 72 are formed on the outer peripheral surface 71 of the first bearing 7. These grooves 72 constitute a first bearing through passage 68 that communicates the first bearing front chamber 73 and the plunger front chamber 74.

  The base 2 has a cylindrical flange tube portion 20, and the flange tube portion 20 is fitted in a mounting hole of a mating mother machine (not shown). An O-ring 18 is fitted on the outer periphery of the flange cylindrical portion 20, and the space between the mounting hole of the mother machine is sealed by the O-ring 18 so that hydraulic oil does not leak outside from the mounting hole.

  In this case, when the solenoid 1 is assembled to the mother machine and the hydraulic oil (not shown) of the mother machine is filled with hydraulic oil, the hydraulic oil from the mother machine is filled into the solenoid 1 through the following path.

  The hydraulic oil from the mother machine is filled into the first bearing front chamber 73 through the base through passage 62 (gap 56).

  The hydraulic fluid in the first bearing front chamber 73 is filled into the plunger front chamber 74 through the first bearing through passage 68 (groove 72).

  The hydraulic oil in the plunger front chamber 74 is filled into the plunger back chamber 75 through (gap 55, groove 42).

  The hydraulic oil in the plunger back chamber 75 is filled into the second bearing back chamber 76 through the second bearing through passage 64 (groove 82).

  When the coil 12 is energized and the shaft 5 moves forward (leftward in FIG. 4), the volume of hydraulic oil in which the shaft 5 retreats from the second bearing rear chamber 76 is the base machine → base through passage 62 → first. It flows into the second bearing rear chamber 76 through the bearing front chamber 73 → the first bearing through passage 68 → the plunger front chamber 74 → the plunger outer peripheral passage 63 → the plunger rear chamber 75 → the second bearing through passage 64.

  At this time, when the plunger 4 moves forward, hydraulic oil corresponding to the moving volume of the plunger 4 flows from the plunger front chamber 74 that contracts into the plunger back chamber 75 that extends through the plunger outer circumferential path 63.

  When the coil 12 is de-energized, the shaft 5 moves rearward (to the right in FIG. 4) by the reaction force received from the hydraulic valve of the mother machine, and opens and closes the hydraulic valve of the mother machine.

  When the shaft 5 moves rearward, the volume of hydraulic oil that the shaft 5 enters from the second bearing back chamber 76 is transferred from the second bearing back chamber 76 to the second bearing through passage 64 → plunger back chamber 75 → plunger outer passage. 63 → Plunger front chamber 74 → First bearing through passage 68 → First bearing front chamber 73 → Base through passage 62 and then flows out to the mother machine.

  At this time, when the plunger 4 moves rearward, the hydraulic oil corresponding to the moving volume of the plunger 4 flows from the plunger back chamber 75 that contracts into the plunger front chamber 74 that extends through the plunger outer peripheral path 63.

  In the present embodiment, a second bearing back chamber 76 that is defined behind the second bearing 8 and is expanded and contracted by the movement of the shaft 5, a plunger back chamber 75 and a second bearing back chamber that penetrate the second bearing 8. The second bearing through passage 64 communicating with 76 and the first bearing through passage 68 passing through the first bearing 7 and communicating between the mother machine and the plunger front chamber 74 are provided. The hydraulic oil corresponding to the expansion / contraction of the bearing back chamber 76 is guided to the plunger outer circumferential path 63 through the plunger back chamber 75.

  In this case, since the shaft through passage 65 (the horizontal through hole 54 and the vertical through hole 53) is abolished, the hydraulic oil corresponding to the expansion and contraction of the second bearing back chamber 76 with the movement of the shaft 5 causes the plunger back chamber 75 to expand and contract. Then, when the movement speed of the shaft 5 is the same when guided to the plunger outer peripheral path 63, the flow rate of the hydraulic oil passing through the plunger outer peripheral path 63 is increased as compared with the embodiment of FIG. Contamination accumulated on the plunger 4 is wiped off by the high-speed hydraulic oil flow passing through the plunger outer peripheral path 63, and the malfunction of the solenoid 1 due to the hydraulic oil contamination can be prevented.

  Next, another embodiment shown in FIG. 5 will be described.

  The front end cover portion 85 is formed in a bowl shape orthogonal to the inner diameter direction from the front end of the outer peripheral cover portion 84 and abuts against the plunger front end surface 47 without a gap.

  An opening 89 facing the groove 42 of the plunger 4 is provided in the front end cover portion 85 so that the front end cover portion 85 does not block the plunger outer peripheral path 63 defined by the groove 42.

  The plunger front end surface 47 has an annular outer peripheral portion 47 a covered with the front end cover portion 85 and an annular inner peripheral exposed portion 47 b not covered with the front end cover portion 85. The inner peripheral exposed portion 47 b is opposed to the inner diameter portion of the base suction surface 46 of the base 2, and defines a space in the inner peripheral portion of the plunger front chamber 74 as a contamination reservoir portion 79.

  In the present embodiment, the plunger outer peripheral path 63 is provided with a groove 42 that opens to the plunger outer peripheral surface 41, and the front end cover portion 85 is provided with an opening 89 that opens to face the groove 42.

  Based on the above configuration, both the front end cover portion 85 is brought into contact with the plunger front end surface 47 without a gap and the plunger outer peripheral path 63 defined by the groove 42 is not blocked. The front end cover portion 85 of the cover 83 made of a non-magnetic material is in contact with the plunger front end surface 47 without any gap, so that contamination is prevented from accumulating on the plunger front end surface 47 and the solenoid 1 can move stably. Can be extended.

Next, a reference example shown in FIG. 6 will be described.

  The cover 83 is formed in a right cylindrical shape, and includes a cylindrical outer cover portion 84 that wraps around the plunger outer peripheral surface 41, and a cylindrical front end eaves portion 86 that projects from the plunger front end surface 47 in an eave shape.

  In this case, since the plunger front end surface 47 is exposed in the entire region inside the front end eaves portion 86, contamination may accumulate on the outer peripheral portion of the front end eaves portion 86. The front end eaves portion 86 protruding in the shape of eaves prevents the contamination accumulated on the front end eaves portion 86 from entering the plunger outer peripheral surface 41 surrounded by the outer peripheral cover portion 84.

  In the present embodiment, the cover 83 has a cylindrical outer peripheral cover portion 84 that wraps around the plunger outer peripheral surface 41 and a front end eaves portion 86 that projects from the plunger front end surface 47 in an eave shape.

  Based on the above-described configuration, the front end eaves portion 86 protruding from the front end of the plunger 4 in an eaves-like manner prevents contamination accumulated on the plunger front end surface 47 from wrapping around the plunger outer peripheral surface 41 surrounded by the outer peripheral cover portion 84. The movable time during which the solenoid 1 operates stably can be extended.

Next, a reference example shown in FIG. 7 will be described.

  The annular first and second scrapers 87 and 88 are projected from the plunger outer peripheral surface 41 in a lip shape. The first scraper 87 is in sliding contact with the base inner peripheral surface 29. The second scraper 88 is in sliding contact with the sleeve inner peripheral surface 34.

  The first and second scrapers 87 and 88 made of a nonmagnetic material are formed of an elastic material such as a resin.

  In this case, the first and second scrapers 87 and 88 projecting in an annular shape from the plunger outer peripheral surface 41 can prevent the contamination from flowing toward the plunger outer peripheral surface 41. Thereby, it is possible to suppress the accumulation of contamination on the strong magnetic field portion B around the plunger, and the movable time during which the solenoid 1 operates stably can be extended.

  As the plunger 4 moves, the first scraper 87 comes into sliding contact with the base inner peripheral surface 29, and the second scraper 88 comes into sliding contact with the sleeve inner peripheral surface 34, whereby the base inner peripheral surface 29 and the sleeve inner peripheral surface are brought into contact. Contamination adhered to the surface 34 is scraped off. As a result, it is possible to suppress the accumulation of contamination on the base inner peripheral surface 29 and the sleeve inner peripheral surface 34 and to extend the movable time during which the solenoid 1 operates stably.

  In the present embodiment, scrapers 87 and 88 made of a non-magnetic material are projected annularly from the plunger outer peripheral surface 41, and the scrapers 87 and 88 serve as inner wall surfaces (base inner peripheral surface 29 and sleeve inner peripheral surface of the plunger outer peripheral path 63. 34).

  Based on the above configuration, the scrapers 87 and 88 scrape off the contaminants adhering to the inner wall surface (base inner circumferential surface 29, sleeve inner circumferential surface 34) of the plunger outer circumferential path 63, and the contamination becomes the inner wall surface (base inner circumferential surface 29, sleeve). Accumulation on the inner peripheral surface 34) can be suppressed, and the movable time during which the solenoid 1 operates stably can be extended.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The solenoid of the present invention is useful for hydraulic equipment, pneumatic equipment, other machines and equipment.

The front view of the solenoid which shows embodiment of this invention. Sectional drawing of the solenoid which similarly follows the AOA line of FIG. The sectional view which expanded the plunger circumference similarly. Sectional drawing of the solenoid which shows other embodiment. Sectional drawing around the plunger showing still another embodiment. Sectional drawing around the plunger showing a reference example . Sectional drawing around the plunger showing a reference example .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solenoid 2 Base 3 Sleeve 4 Plunger 5 Shaft 7 First bearing 8 Second bearing 9 Case 12 Coil 29 Base inner peripheral surface 34 Sleeve inner peripheral surface 41 Plunger outer peripheral surface 55 Gap 63 Plunger outer peripheral path 74 Plunger front chamber 75 Plunger rear chamber

Claims (4)

The plunger is driven by the magnetic field generated in the coil,
Move the shaft coupled to this plunger in the axial direction,
A solenoid that drives the mother machine,
A first bearing and a second bearing that slidably support the shaft across the plunger;
A plunger front chamber defined between the first bearing and the plunger;
A plunger back chamber defined between the plunger and the second bearing;
A plunger outer circumferential path communicating the plunger front chamber and the plunger back chamber;
A cylindrical cover made of a non-magnetic material surrounding the plunger outer peripheral surface,
The plunger outer circumferential path is:
An annular gap defined around the cover;
A groove formed on the outer peripheral surface of the plunger,
The cover has a hook-shaped front end cover portion that wraps the plunger front end surface of the plunger so as not to block the groove,
The plunger front end surface is exposed from the front end cover portion, and has an annular inner peripheral exposed portion that defines a contamination reservoir portion that collects contamination on the inner peripheral side of the plunger front chamber.
A solenoid characterized in that the working fluid of the mother machine is guided to the plunger front chamber, the plunger outer peripheral path, and the plunger back chamber.   The solenoid according to claim 1, wherein the front end cover portion is provided with an opening portion that opens to face the groove. A second bearing rear chamber defined behind the second bearing and enlarged or reduced by movement of the shaft;
A shaft penetration path that penetrates the shaft in the axial direction and communicates the mother machine and the second bearing back chamber;
A second bearing through passage that passes through the second bearing and communicates the plunger back chamber and the second bearing back chamber;
Blocking communication between the mother machine and the plunger front chamber by the first bearing,
The working fluid of the mother machine is configured to be guided to the plunger back chamber through the shaft through passage, the second bearing back chamber, and the second bearing through passage. solenoid. A second bearing rear chamber defined behind the second bearing and enlarged or reduced by movement of the shaft;
A second bearing through passage passing through the second bearing and communicating the plunger back chamber and the second bearing back chamber;
A first bearing through passage that passes through the first bearing and communicates the mother machine and the plunger front chamber;
According to claim 1 or 2, characterized in that a structure in which the second bearing behind chamber in accordance with the movement of the shaft is minute working fluid scaling is guided to the plunger outer peripheral path through said plunger back chamber Solenoid.

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