This application is based on Japanese patent application No. 2021-85175 filed on May 20, 2021, the entire content of which is incorporated herein by reference.
The present disclosure relates to a solenoid.
A solenoid has a yoke formed of a magnetic material, a coil arranged inside the yoke, a stator core formed of a magnetic material arranged inside the coil, and a plunger arranged inside the stator core.
According to one embodiment of the present disclosure, a solenoid for driving the shaft in a direction along a central axis is provided. The solenoid includes a coil that generates magnetic flux and a magnetic container that accommodates the coil. The container has a side surface portion and a bottom portion, and the side surface portion and a part of the bottom portion act as a yoke through which the magnetic flux passes. Further, a plunger arranged inside the coil and sliding in a direction along the central axis to move the shaft, and a stator core formed of a magnetic material are provided. The stator core has a plunger accommodating portion and a shaft accommodating portion that accommodates the shaft and attracts the plunger by an action of the magnetic flux. The plunger accommodating portion has a cylindrical core portion that accommodates the plunger inside, and a flange portion that is provided radially outward at an end of the core portion on the bottom portion side and is welded to the bottom portion of the container. Further, a ring core provided on the opposite side of the shaft accommodating portion to the plunger accommodating portion is provided.
In an assumable example, a solenoid has a yoke formed of a magnetic material, a coil arranged inside the yoke, a stator core formed of a magnetic material arranged inside the coil, and a plunger arranged inside the stator core. The solenoid generates a magnetic force by energizing the coil and slides the plunger with respect to the stator core. In the solenoid, a ring core is provided on an outer periphery of the stator core, and the ring core is pressed against a bottom of the yoke by an elastic member provided in a space between the ring core and the yoke.
In such a solenoid, magnetic flux is less likely to pass through the space where the elastic member is arranged as compared with a bottom of the yoke, the ring core, and the stator core formed of the magnetic material. Therefore, it is difficult to increase a magnetic efficiency when sliding the plunger. Therefore, there is a demand for a configuration capable of increasing magnetic efficiency.
The present disclosure has been made to solve at least a part of the above problems, and can be implemented as the following embodiments.
According to one embodiment of the present disclosure, a solenoid for driving the shaft in a direction along a central axis is provided. The solenoid includes a coil that generates magnetic flux and a magnetic container that accommodates the coil. The container has a side surface portion and a bottom portion, and the side surface portion and a part of the bottom portion act as a yoke through which the magnetic flux passes. Further, a plunger arranged inside the coil and sliding in a direction along the central axis to move the shaft, and a stator core formed of a magnetic material are provided. The stator core has a plunger accommodating portion and a shaft accommodating portion that accommodates the shaft and attracts the plunger by an action of the magnetic flux. The plunger accommodating portion has a cylindrical core portion that accommodates the plunger inside, and a flange portion that is provided radially outward at an end of the core portion on the bottom portion side and is welded to the bottom portion of the container. Further, a ring core provided on the opposite side of the shaft accommodating portion to the plunger accommodating portion is provided.
According to the solenoid of this configuration, by welding the flange portion and the bottom portion, an elastic member that presses the flange portion to the bottom portion and a space in which the elastic member is arranged are not provided between the coil and the flange portion. Therefore, it is possible to increase the magnetic efficiency without making it difficult for the magnetic flux to pass through the space.
The present disclosure can be realized as the following embodiments. For example, the present disclosure can be realized in the embodiment of a solenoid valve, a method of manufacturing a solenoid, and the like.
A linear solenoid valve 300 shown in
The spool valve 200 includes a sleeve 210, a spool 220, a spring 230, and an adjust screw 240. The solenoid 100 functions as an actuator for driving the spool 220 of the spool valve 200.
The sleeve 210 has a substantially cylindrical external shape. The sleeve 210 has an insertion hole 212 penetrating along a central axis AX, and a plurality of oil ports 214 communicating with the insertion hole 212 and opening in a radial direction. The spool 220 is inserted into the insertion hole 212. The plurality of oil ports 214 are formed on a side surface of the sleeve 210 side by side in the direction along the central axis AX. The plurality of oil ports 214 function, for example, as an input port that communicates with an oil pump (not shown) to receive oil supply, an output port that communicates with a clutch piston (not shown) to supply oil pressure, a drain port that discharges hydraulic oil, and the like. At the end of the sleeve 210 on the solenoid 100 side (a direction AE side), a flange portion 216 whose diameter increases toward the outside in the radial direction is formed. The flange portion 216 is fixed to each other with a container 10 of the solenoid 100 described later.
The spool 220 has a substantially rod-like external shape in which a plurality of large-diameter portions 222 and small-diameter portions 224 are arranged side by side along the central axis AX. The spool 220 slides along the central axis AX inside the insertion hole 212, and adjusts a communication state and an opening area of the plurality of oil ports 214 according to a position along the central axis AX between the large-diameter portion 222 and the small-diameter portion 224.
A shaft 90 for transmitting a thrust of the solenoid 100 to the spool 220 is arranged at the end of the spool 220 on the solenoid 100 side (the direction AE side). A spring 230 is arranged at the other end (the direction AD side) of the spool 220. The spring 230 is composed of a compression coil spring, and presses the spool 220 in the solenoid 100 direction (the direction AE side) along the central axis AX. As a result, the spool 220 comes into contact with the shaft 90. The adjust screw 240 is arranged in contact with the spring 230, and adjusts a spring load of the spring 230 by adjusting a screwing amount of the adjust screw 240 to the sleeve 210 so as to adjust a pressing force of the spool 220 in the solenoid 100 direction. The spool 220 is located at a position where the thrust of the solenoid 100 and the pressing force due to the spring load of the spring 230 are balanced.
The solenoid 100 shown in
As shown in
The coil 20, the stator core 40, and the plunger 30 are housed in the container 10. The coil 20 is arranged inside the side surface portion 12 of the container 10. The coil 20 is configured by winding a lead wire with an insulating coating around a resin bobbin 22 arranged inside the side surface portion 12 of the container 10. An end of the lead wire forming the coil 20 is connected to a connection terminal 24. The connection terminal 24 is arranged inside a connector 26. The connector 26 is arranged on the outer peripheral portion of the container 10 and electrically connects the solenoid 100 and the electronic control unit via a connection line (not shown).
The stator core 40 is arranged inside the coil 20. The stator core 40 is made of, for example, a magnetic material such as iron, and includes a thin-walled portion 70 formed by a recess on the outer periphery of a central portion along the axial direction AX. The starter core 40 has a shaft accommodating portion 50 in which a small-diameter hollow portion in which the shaft 90 is slidably accommodated is formed, and a plunger accommodating portion 60 in which a larger-diameter hollow portion in which the plunger 30 is slidably accommodated is formed. In the stator core 40, the shaft accommodating portion 50 and the plunger accommodating portion 60 are functionally separated by the thin-walled portion 70. The thin-walled portion 70 is formed on an outer periphery of the plunger accommodating portion 60, and acts as a magnetic flux passage suppressing portion that makes it difficult for magnetic flux to pass through. A wall thickness of the thin-walled portion 70 is extremely thin, about ¼ to 1/10, as compared with the wall thickness of the plunger accommodating portion 60. Therefore, as will be described later, the magnetic flux is suppressed from passing along the plunger accommodating portion 60, and a considerable part of the magnetic flux passes through the plunger 30 side. It is preferable to provide the thin-walled portion 70 because a considerable portion of the magnetic flux passes through the plunger 30 side, but the thin-walled portion 70 can be omitted.
A flange portion 65 protruding radially outward from the central axis AX is formed at the end of the plunger accommodating portion 60 on the bottom portion 14 side, and the stator core 40 is fixed to the bottom portion 14 by the flange portion 65. The fixed structure of the starter core 40 will be described in detail later. A part of the plunger accommodating portion 60 excluding the flange portion 65 is referred to as a core portion 61. The core portion 61 has a cylindrical shape having a hollow having an inner diameter larger than that of the shaft accommodating portion 50. The plunger 30 is inserted into the hollow of the core portion 61 with a slight sliding gap from an inner peripheral surface thereof. A stopper 52 is arranged on a surface of the shaft accommodating portion 50 facing the end surface (hereinafter, also referred to as “tip surface 32”) of the plunger 30 on the spool valve 200 side. The stopper 52 is made of a non-magnetic material and suppresses a direct contact between the plunger 30 and the shaft accommodating portion 50, and suppresses the plunger 30 from becoming difficult to separate from the shaft accommodating portion 50 by magnetic attraction.
The flange portion 65 is a portion formed toward the outside in the radial direction over the entire circumference of the end portion 62 on the bottom portion 14 side of the plunger accommodating portion 60. The flange portion 65 is located between the bobbin 22 and the bottom portion 14 of the container 10. The flange portion 65 is welded to the bottom portion 14 of the container 10. The flange portion 65 transfers magnetic flux between the container 10 and the plunger 30 via the core portion 61. More specifically, the flange portion 65 transfers the magnetic flux between the bottom portion 14 of the container 10 and the plunger 30. The flange portion 65 may transfer magnetic flux between the side surface portion 12 of the container 10 and the plunger 30. In the present embodiment, a radial gap is provided between the flange portion 65 and the side surface portion 12 of the container 10 for easy assembly.
The plunger 30 has a substantially columnar appearance shape and is made of a magnetic material such as iron. As described above, since the plunger 30 is inserted into the hollow part of the core portion 61 with a slight sliding gap from the inner peripheral surface, the plunger 30 slides in the inner peripheral surface of the plunger accommodating portion 60 of the stator core 40 in the direction AD side or the direction AE side. The shaft 90 described above is arranged on a tip surface 32 of the plunger 30, and the shaft 90 is urged in the direction of the plunger 30 by the spring 230 and is in contact with the plunger 30. Further, the plunger 30 is urged toward the bottom portion 14 side of the container 10, that is, the direction AE side by the urging force of the spring 230 transmitted to the spool 220. The end surface (hereinafter, also referred to as “base end surface 34”) opposite to the tip surface 32 faces the bottom portion 14 of the container 10. The plunger 30 is formed with an air vent hole (not shown) penetrating along the central axis AX. Such an air vent hole allows fluids located on the base end surface 34 side and the tip surface 32 side of the plunger 30, such as hydraulic oil and air, to pass through.
The thin-walled portion 70 is formed between the shaft accommodating portion 50 and the core portion 61 in the direction along the central axis AX. The thin-walled portion 70 suppresses the direct flow of magnetic flux between the core portion 61 and the shaft accommodating portion 50. In the present embodiment, the thin-walled portion 70 is configured such that the radial thickness of the stator core 40, which is a magnetic material, is formed to be thin, so that the magnetic resistance of the thin-walled portion 70 is larger than that of the shaft accommodating portion 50 and the core portion 61.
The ring core 80 is arranged between the coil 20 and the flange portion 216 of the spool valve 200 on the direction AD side of the coil 20. In other words, the ring core 80 is arranged at the end on the direction AD side of the shaft accommodating portion 50 of the stator core 40, which will be described later, and on the radial outside of the end portion (hereinafter, also referred to as “end portion 54”) on the side opposite to the plunger 30 side. The ring core 80 has a ring-shaped appearance and is made of a magnetic material such as iron. The ring core 80 transfers magnetic flux between the shaft accommodating portion 50 of the stator core 40 and the side surface portion 12 of the container 10. The ring core 80 is configured to be displaceable in the radial direction. As a result, variations in the dimensions of the stator core 40 during manufacture and imperfect alignment of the stator core 40 during assembly are absorbed. In the present embodiment, the shaft accommodating portion 50 is fitted to the ring core 80 with a slight radial gap. The shaft accommodating portion 50 may be press-fitted into the ring core 80.
When the coil 20 is not energized, the plunger 30 is urged by the spring 230 via the shaft 90 and is in contact with the bottom portion 14 of the container 10. The coil 20 generates a magnetic force when energized, and as shown in
In the present embodiment, the container 10, the ring core 80, the plunger 30, and the stator core 40 are each composed of iron, which is a magnetic material, but they are not limited to iron, and may be composed of any magnetic substance such as nickel and cobalt. In the present embodiment, the container 10 is formed by press molding and the stator core 40 is formed by forging, but each may be formed by any molding method.
As shown in
In the first embodiment, the bottom portion 14 of the container 10 and the flange portion 65 of the stator core 40 are fixed by welding. Therefore, an elastic member that presses the flange portion 65 against the bottom portion 14 and a space for accommodating the elastic member are not required. When the magnetic flux flows from the bottom portion 14 through the flange portion 65 to the plunger 30, if the magnetic flux passes through a space in which the magnetic flux is difficult to pass, the magnetic efficiency is lowered. However, in the present embodiment, the magnetic flux does not pass through the space where the magnetic flux is difficult to pass, but passes through the magnetic material, so that the magnetic efficiency can be improved. Here, the magnetic efficiency is defined by the attractive force with respect to the magnitude of the magnetic flux received when the shaft accommodating portion 50 receiving the magnetic flux attracts the plunger 30. That is, even if the magnitude of the magnetic flux is the same, if the shaft accommodating portion 50 can attract the plunger 30 more strongly, it is determined that the magnetic efficiency is good.
In the first embodiment, since the bottom portion 14 of the container 10 and the flange portion 65 of the stator core 40 are spot welded, they can be welded in a short time and distortion due to welding can be less likely to occur.
In the first embodiment, it is preferable that the welded portion 16 is formed on the outer peripheral side of an intermediate position 65m between an inner peripheral 65i and an outer peripheral 65o of the flange portion 65. During welding, spatter such as slag and metal particles occurs. When the welded portion 16, that is, the welded position is on the outer peripheral side of the intermediate position 65m between the inner peripheral 65i and the outer peripheral 65o of the flange portion 65, the spatter generated during welding can be suppressed from flying into the space between the plunger 30 and the bottom portion 14 of the container 10.
In the solenoid 100a of a second embodiment shown in
Also in the second embodiment, as in the first embodiment, the bottom portion 14 of the container 10 and the flange portion 65 of the stator core 40 are fixed by welding. Therefore, an elastic member that presses the flange portion 65 against the bottom portion 14 and a space for accommodating the elastic member are not required. When the magnetic flux flows from the bottom portion 14 through the flange portion 65 to the plunger 30, if the magnetic flux passes through a space in which the magnetic flux is difficult to pass, the magnetic efficiency is lowered. However, in the present embodiment, the magnetic flux does not pass through the space where the magnetic flux is difficult to pass, but passes through the magnetic material, so that the magnetic efficiency can be improved.
In the second embodiment, the bottom portion 14 of the container 10 and the flange portion 65 of the stator core 40 are welded all around the circumference along the circumference centered on the central axis AX, so that the welding strength is increased.
In the second embodiment, as in the first embodiment, it is preferable that the welded portion 16a is formed on the outer peripheral side of an intermediate position 65m between an inner peripheral 65i and an outer peripheral 65o of the flange portion 65. During welding, spatter such as slag and metal particles occurs. When the welded portion 16a, that is, the welded position is on the outer peripheral side of the intermediate position 65m between the inner peripheral 65i and the outer peripheral 65o of the flange portion 65, the spatter generated during welding can be suppressed from flying into the space between the plunger 30 and the bottom portion 14 of the container 10.
In the second embodiment, the welded portion 16a is formed all around the circumference along the circumference centered on the central axis AX. However, when the air vent groove in the direction perpendicular to the central axis AX is formed on the surface of the flange portion 65 on the bottom portion 14 side, the welded portion 16a may be formed so as to avoid the air vent groove. That is, even if the welded portion 16a is not formed all around the circumference along the circumference centered on the central axis AX, it may be formed substantially all around the circumference.
Although description will be omitted from the third embodiment to be described later, the welding may be spot welding as in the first embodiment, and the welded portion may be formed all around the circumference along the circumference centered on the central axis AX as in the second embodiment. Further, it is preferable that the welded portion is formed on the outer peripheral side of the intermediate position 65m between the inner peripheral 65i and the outer peripheral 65o of the flange portion 65.
In the solenoid 100b of a third embodiment shown in
According to the solenoid 100b of the third embodiment, the core portion 61b and the flange portion 65b of the stator core 40b are separate parts, and each of them can be manufactured separately. Here, the shape of the core portion 61b is a substantially cylindrical shape, and the shape of the flange portion 65b is a perforated disk shape, both of which are simple in shape. Therefore, the stator core 40b can be easily manufactured by separately manufacturing the core portion 61b and the flange portion 65b and press-fitting the flange portion 65b into the core portion 61b.
The solenoid 100c of a fourth embodiment shown in
According to the solenoid 100c of the fourth embodiment, the core portion 61c and the flange portion 65c of the stator core 40c are separate parts, the shape of the core portion 61c is a substantially cylindrical shape, and the shape of the flange portion 65c is a perforated disk shape. Therefore, both are simple in shape. Therefore, by separately manufacturing the core portion 61c and the flange portion 65c, the stator core 40c can be easily manufactured. Further, in the solenoid 100c of the fourth embodiment, since the flange portion 65c is not press-fitted into the core portion 61c, the manufacturing process can be simplified.
In the solenoid 100c of the fourth embodiment, an elastic member is arranged between the stator core 40c and the sleeve 210, and the elastic member may press the stator core 40c toward the bottom portion 14 along the central axis AX.
In the solenoid 100d of a fifth embodiment shown in
When manufacturing the solenoid 100d, the ring core 80 is fixed after welding the bottom portion 14 of the container 10d and the flange portion 65d of the stator core 40. According to the solenoid 100d of the fifth embodiment, since the container 10d and the ring core 80 are fixed by welding, the stress applied to the previously welded portion 16d can be reduced in comparison with the case where the ring core 80 is fixed by caulking the opening portion 17 of the container 10. Further, as compared with the case where the opening portion 17 of the container 10 is caulked to fix the ring core 80, the gap between the ring core and the core stator does not need to be widened, so that the size of the coil 20 and the current driving the coil 20 can be reduced without lowering the magnetic efficiency.
In the solenoid 100e of a sixth embodiment shown in
According to the solenoid 100e of the sixth embodiment, the side surface portion 12e and the bottom portion 14e of the container 10e are separate parts, the shape of the side surface portion 12e is a substantially cylindrical shape, and the shape of the bottom portion 14e is a disk shape. Therefore, both are simple in shape. Therefore, the core portion 61e and the flange portion 65e can be manufactured separately, and the container 10e can be easily manufactured by press-fitting the bottom portion 14e into the side surface portion 12e. In the sixth embodiment, the bottom portion 14e is press-fitted into the side surface portion 12e, but the side surface portion 12e may be caulked and fixed to the bottom portion 14e.
In the solenoid 100f of a seventh embodiment shown in
According to the solenoid 100f of the seventh embodiment, since the shaft accommodating portion 50f and the plunger accommodating portion 60f are separated, the magnetic flux does not flow directly from the plunger accommodating portion 60f to the shaft accommodating portion 50f and flows from the plunger accommodating portion 60f to the shaft accommodating portion 50f via the plunger 30. As a result, more magnetic flux passes through the plunger 30, so that magnetic efficiency can be improved.
In the solenoid 100g of the eighth embodiment shown in
According to the solenoid 100g of the seventh embodiment, since the shaft accommodating portion 50g and the plunger accommodating portion 60g are separated, the magnetic flux does not flow directly from the plunger accommodating portion 60g to the shaft accommodating portion 50g and flows from the plunger accommodating portion 60g to the shaft accommodating portion 50g via the plunger 30. As a result, more magnetic flux passes through the plunger 30, so that magnetic efficiency can be improved.
The solenoid 100h of a ninth embodiment shown in
According to the solenoid 100h of the ninth embodiment, a contact area between the ring core 80h and the shaft accommodating portion 50h can be increased, so that the magnetic flux can be easily transferred between the shaft accommodating portion 50h of the stator core 40h and the side surface portion 12 of the container 10.
The present disclosure should not be limited to the embodiments described above, and various other embodiments may be implemented without departing from the scope of the present disclosure. For example, the technical features in each embodiment corresponding to the technical features in the form described in the summary may be used to solve some or all of the above-described problems, or to provide one of the above-described effects. In order to achieve a part or all, replacement or combination can be appropriately performed. Also, if the technical features are not described as essential in the present specification, they can be deleted as appropriate.
Number | Date | Country | Kind |
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2021-085175 | May 2021 | JP | national |