Patent ID: 12198854

DETAILED DESCRIPTION

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.

First Embodiment

A linear solenoid valve300shown inFIG.1is, for example, a device used for controlling a hydraulic pressure of hydraulic oil supplied to an automatic transmission for a vehicle. The linear solenoid valve300includes a solenoid100and a spool valve200. The solenoid100and the spool valve200are arranged along a central axis AX.

The spool valve200includes a sleeve210, a spool220, a spring230, and an adjust screw240. The solenoid100functions as an actuator for driving the spool220of the spool valve200.

The sleeve210has a substantially cylindrical external shape. The sleeve210has an insertion hole212penetrating along a central axis AX, and a plurality of oil ports214communicating with the insertion hole212and opening in a radial direction. The spool220is inserted into the insertion hole212. The plurality of oil ports214are formed on a side surface of the sleeve210side by side in the direction along the central axis AX. The plurality of oil ports214function, 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 sleeve210on the solenoid100side (a direction AE side), a flange portion216whose diameter increases toward the outside in the radial direction is formed. The flange portion216is fixed to each other with a container10of the solenoid100described later.

The spool220has a substantially rod-like external shape in which a plurality of large-diameter portions222and small-diameter portions224are arranged side by side along the central axis AX. The spool220slides along the central axis AX inside the insertion hole212, and adjusts a communication state and an opening area of the plurality of oil ports214according to a position along the central axis AX between the large-diameter portion222and the small-diameter portion224.

A shaft90for transmitting a thrust of the solenoid100to the spool220is arranged at the end of the spool220on the solenoid100side (the direction AE side). A spring230is arranged at the other end (the direction AD side) of the spool220. The spring230is composed of a compression coil spring, and presses the spool220in the solenoid100direction (the direction AE side) along the central axis AX. As a result, the spool220comes into contact with the shaft90. The adjust screw240is arranged in contact with the spring230, and adjusts a spring load of the spring230by adjusting a screwing amount of the adjust screw240to the sleeve210so as to adjust a pressing force of the spool220in the solenoid100direction. The spool220is located at a position where the thrust of the solenoid100and the pressing force due to the spring load of the spring230are balanced.

The solenoid100shown inFIGS.1and2includes a container10, a coil20, a plunger30, a stator core40, and a ring core80. When the coil20is energized and controlled by an electronic control unit (not shown), in the solenoid100, the plunger30moves by a magnetic flux generated by the coil20. As the plunger30moves, the spool220of the spool valve200moves in a direction AD via the shaft90in contact with the plunger30.

As shown inFIG.2, the container10constitutes an outer shell of the solenoid100. The container10is formed of a magnetic material such as iron and functions as a yoke. The container10includes a side surface portion12, a bottom portion14, and an opening portion17. The side surface portion12has a substantially cylindrical appearance shape along the central axis AX. The bottom portion14closes an end of the side surface portion12at an end of the side surface portion12on a side (a direction AE side) opposite to the spool valve200. An end of the side surface portion12on the spool valve200side (a direction AD side) is formed to be thin and configures a thin-walled portion15. The opening portion17is formed in the thin-walled portion15at the end of the side surface portion12on the spool valve200side. After the components of the solenoid100are assembled inside the container10, the opening portion17is caulked and fixed to a flange portion216of the spool valve200. Instead of caulking, the spool valve200and the container10may be fixed by any method such as welding.

The coil20, the stator core40, and the plunger30are housed in the container10. The coil20is arranged inside the side surface portion12of the container10. The coil20is configured by winding a lead wire with an insulating coating around a resin bobbin22arranged inside the side surface portion12of the container10. An end of the lead wire forming the coil20is connected to a connection terminal24. The connection terminal24is arranged inside a connector26. The connector26is arranged on the outer peripheral portion of the container10and electrically connects the solenoid100and the electronic control unit via a connection line (not shown).

The stator core40is arranged inside the coil20. The stator core40is made of, for example, a magnetic material such as iron, and includes a thin-walled portion70formed by a recess on the outer periphery of a central portion along the axial direction AX. The starter core40has a shaft accommodating portion50in which a small-diameter hollow portion in which the shaft90is slidably accommodated is formed, and a plunger accommodating portion60in which a larger-diameter hollow portion in which the plunger30is slidably accommodated is formed. In the stator core40, the shaft accommodating portion50and the plunger accommodating portion60are functionally separated by the thin-walled portion70. The thin-walled portion70is formed on an outer periphery of the plunger accommodating portion60, 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 portion70is extremely thin, about ¼ to 1/10, as compared with the wall thickness of the plunger accommodating portion60. Therefore, as will be described later, the magnetic flux is suppressed from passing along the plunger accommodating portion60, and a considerable part of the magnetic flux passes through the plunger30side. It is preferable to provide the thin-walled portion70because a considerable portion of the magnetic flux passes through the plunger30side, but the thin-walled portion70can be omitted.

A flange portion65protruding radially outward from the central axis AX is formed at the end of the plunger accommodating portion60on the bottom portion14side, and the stator core40is fixed to the bottom portion14by the flange portion65. The fixed structure of the starter core40will be described in detail later. A part of the plunger accommodating portion60excluding the flange portion65is referred to as a core portion61. The core portion61has a cylindrical shape having a hollow having an inner diameter larger than that of the shaft accommodating portion50. The plunger30is inserted into the hollow of the core portion61with a slight sliding gap from an inner peripheral surface thereof. A stopper52is arranged on a surface of the shaft accommodating portion50facing the end surface (hereinafter, also referred to as “tip surface32”) of the plunger30on the spool valve200side. The stopper52is made of a non-magnetic material and suppresses a direct contact between the plunger30and the shaft accommodating portion50, and suppresses the plunger30from becoming difficult to separate from the shaft accommodating portion50by magnetic attraction.

The flange portion65is a portion formed toward the outside in the radial direction over the entire circumference of the end portion62on the bottom portion14side of the plunger accommodating portion60. The flange portion65is located between the bobbin22and the bottom portion14of the container10. The flange portion65is welded to the bottom portion14of the container10. The flange portion65transfers magnetic flux between the container10and the plunger30via the core portion61. More specifically, the flange portion65transfers the magnetic flux between the bottom portion14of the container10and the plunger30. The flange portion65may transfer magnetic flux between the side surface portion12of the container10and the plunger30. In the present embodiment, a radial gap is provided between the flange portion65and the side surface portion12of the container10for easy assembly.

The plunger30has a substantially columnar appearance shape and is made of a magnetic material such as iron. As described above, since the plunger30is inserted into the hollow part of the core portion61with a slight sliding gap from the inner peripheral surface, the plunger30slides in the inner peripheral surface of the plunger accommodating portion60of the stator core40in the direction AD side or the direction AE side. The shaft90described above is arranged on a tip surface32of the plunger30, and the shaft90is urged in the direction of the plunger30by the spring230and is in contact with the plunger30. Further, the plunger30is urged toward the bottom portion14side of the container10, that is, the direction AE side by the urging force of the spring230transmitted to the spool220. The end surface (hereinafter, also referred to as “base end surface34”) opposite to the tip surface32faces the bottom portion14of the container10. The plunger30is 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 surface34side and the tip surface32side of the plunger30, such as hydraulic oil and air, to pass through.

The thin-walled portion70is formed between the shaft accommodating portion50and the core portion61in the direction along the central axis AX. The thin-walled portion70suppresses the direct flow of magnetic flux between the core portion61and the shaft accommodating portion50. In the present embodiment, the thin-walled portion70is configured such that the radial thickness of the stator core40, which is a magnetic material, is formed to be thin, so that the magnetic resistance of the thin-walled portion70is larger than that of the shaft accommodating portion50and the core portion61.

The ring core80is arranged between the coil20and the flange portion216of the spool valve200on the direction AD side of the coil20. In other words, the ring core80is arranged at the end on the direction AD side of the shaft accommodating portion50of the stator core40, which will be described later, and on the radial outside of the end portion (hereinafter, also referred to as “end portion54”) on the side opposite to the plunger30side. The ring core80has a ring-shaped appearance and is made of a magnetic material such as iron. The ring core80transfers magnetic flux between the shaft accommodating portion50of the stator core40and the side surface portion12of the container10. The ring core80is configured to be displaceable in the radial direction. As a result, variations in the dimensions of the stator core40during manufacture and imperfect alignment of the stator core40during assembly are absorbed. In the present embodiment, the shaft accommodating portion50is fitted to the ring core80with a slight radial gap. The shaft accommodating portion50may be press-fitted into the ring core80.

When the coil20is not energized, the plunger30is urged by the spring230via the shaft90and is in contact with the bottom portion14of the container10. The coil20generates a magnetic force when energized, and as shown inFIG.2, a loop-shaped magnetic flux flow (hereinafter, also referred to as “magnetic circuit C1”) passing through the side surface portion12of the container10, the bottom portion14of the container10, the core portion61of the stator core40, the plunger30, and the ring core80is formed. At this time, the plunger30is magnetically attracted by the shaft accommodating portion50and moves in the direction of the spool valve200(the direction AD side) along the central axis AX. At this time, the plunger30moves against the urging force of the spring230, and moves to a position where the magnetic attraction force and the urging force of the spring230are balanced. As a result, the communication state and the opening area of the oil port214are adjusted, and the oil pressure is output according to the current value flowing through the coil20. As the current flowing through the coil20increases, the magnetic flux density of the magnetic circuit C1increases, and the magnetic attraction force by the shaft accommodating portion50increases, so that the amount of movement of the plunger30increases. When the tip surface32of the plunger30and the stopper52come into contact with each other, the plunger30does not move any further. The state shown inFIGS.1and2is a state in which the coil20is not energized and a magnetic circuit is not formed, and the plunger30is in contact with the bottom portion14of the container10. InFIG.2, for convenience of explanation, the magnetic circuit C1formed when the coil20is energized is schematically shown by a thick line arrow.

In the present embodiment, the container10, the ring core80, the plunger30, and the stator core40are 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 container10is formed by press molding and the stator core40is formed by forging, but each may be formed by any molding method.

As shown inFIGS.2and3, the bottom portion14of the solenoid100is welded to the flange portion65of the plunger accommodating portion60by laser spot welding by laser irradiation to form the welded portion16. In this embodiment, there are three welded points. These three welded points may be evenly arranged around the central axis AX, but may be unevenly arranged. For example, when the air vent groove in the direction perpendicular to the central axis AX is formed on the surface of the flange portion65on the bottom portion14side, the welded portion16is unevenly arranged for avoiding the air vent groove. InFIG.3, the portions melted by the laser irradiation are shown as the welded portions16, but since the molten metal has a continuous composition with the bottom portion14and the flange portion65, the illustration inFIG.3is schematic.

In the first embodiment, the bottom portion14of the container10and the flange portion65of the stator core40are fixed by welding. Therefore, an elastic member that presses the flange portion65against the bottom portion14and a space for accommodating the elastic member are not required. When the magnetic flux flows from the bottom portion14through the flange portion65to the plunger30, 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 portion50receiving the magnetic flux attracts the plunger30. That is, even if the magnitude of the magnetic flux is the same, if the shaft accommodating portion50can attract the plunger30more strongly, it is determined that the magnetic efficiency is good.

In the first embodiment, since the bottom portion14of the container10and the flange portion65of the stator core40are 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 portion16is formed on the outer peripheral side of an intermediate position65mbetween an inner peripheral65iand an outer peripheral65oof the flange portion65. During welding, spatter such as slag and metal particles occurs. When the welded portion16, that is, the welded position is on the outer peripheral side of the intermediate position65mbetween the inner peripheral65iand the outer peripheral65oof the flange portion65, the spatter generated during welding can be suppressed from flying into the space between the plunger30and the bottom portion14of the container10.

Second Embodiment

In the solenoid100aof a second embodiment shown inFIG.4, the welded portion16ais formed all around the circumference along the circumference centered on the central axis AX. In the solenoid100a, the bottom portion14and the flange portion65are welded to one circumference along the circumference centered on the central axis AX. Therefore, in this respect, it is different from the solenoid100of the first embodiment, in which the three welded portions16are spot-welded. The solenoid100aof the second embodiment and the solenoid100of the first embodiment have the same configuration other than the welded position.

Also in the second embodiment, as in the first embodiment, the bottom portion14of the container10and the flange portion65of the stator core40are fixed by welding. Therefore, an elastic member that presses the flange portion65against the bottom portion14and a space for accommodating the elastic member are not required. When the magnetic flux flows from the bottom portion14through the flange portion65to the plunger30, 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 portion14of the container10and the flange portion65of the stator core40are 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 portion16ais formed on the outer peripheral side of an intermediate position65mbetween an inner peripheral65iand an outer peripheral65oof the flange portion65. During welding, spatter such as slag and metal particles occurs. When the welded portion16a, that is, the welded position is on the outer peripheral side of the intermediate position65mbetween the inner peripheral65iand the outer peripheral65oof the flange portion65, the spatter generated during welding can be suppressed from flying into the space between the plunger30and the bottom portion14of the container10.

In the second embodiment, the welded portion16ais 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 portion65on the bottom portion14side, the welded portion16amay be formed so as to avoid the air vent groove. That is, even if the welded portion16ais 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 position65mbetween the inner peripheral65iand the outer peripheral65oof the flange portion65.

Third Embodiment

In the solenoid100bof a third embodiment shown inFIG.5, the core portion61band the flange portion65bof the stator core40are separate parts, and the flange portion65bis press-fitted into the core portion61b. In this respect, it differs from the solenoid100of the first embodiment. Configuration of the solenoid100bof the third embodiment except that the core portion61band the flange portion65bof the stator core40are separate parts, and the flange portion65bis press-fitted into the core portion61bis the same as the solenoid100of the first embodiment.

According to the solenoid100bof the third embodiment, the core portion61band the flange portion65bof the stator core40bare separate parts, and each of them can be manufactured separately. Here, the shape of the core portion61bis a substantially cylindrical shape, and the shape of the flange portion65bis a perforated disk shape, both of which are simple in shape. Therefore, the stator core40bcan be easily manufactured by separately manufacturing the core portion61band the flange portion65band press-fitting the flange portion65binto the core portion61b.

Fourth Embodiment

The solenoid100cof a fourth embodiment shown inFIG.6is the same as the solenoid100bof the third embodiment in that the core portion61cand the flange portion65cof the stator core40are separate parts. However, in the solenoid100bof the third embodiment, the flange portion65bis press-fitted into the core portion61b, but in the solenoid100cof the fourth embodiment, the flange portion65cis not press-fitted into the core portion61cand is in contact with the core portion61cin the direction along the central axis AX, and is sandwiched between the core portion61cand the bottom portion14. In this respect, it differs from the solenoid100bof the third embodiment.

According to the solenoid100cof the fourth embodiment, the core portion61cand the flange portion65cof the stator core40care separate parts, the shape of the core portion61cis a substantially cylindrical shape, and the shape of the flange portion65cis a perforated disk shape. Therefore, both are simple in shape. Therefore, by separately manufacturing the core portion61cand the flange portion65c, the stator core40ccan be easily manufactured. Further, in the solenoid100cof the fourth embodiment, since the flange portion65cis not press-fitted into the core portion61c, the manufacturing process can be simplified.

In the solenoid100cof the fourth embodiment, an elastic member is arranged between the stator core40cand the sleeve210, and the elastic member may press the stator core40ctoward the bottom portion14along the central axis AX.

Fifth Embodiment

In the solenoid100dof a fifth embodiment shown inFIG.7, the container10ddoes not have the thin-walled portion15, and is welded to the ring core80at the opening portion17dof the container10dto form the welded portion19d. Therefore, in this respect, it is different from the solenoid100of the first embodiment. Regarding other configurations, the solenoid100dof the fifth embodiment and the solenoid100of the first embodiment are the same.

When manufacturing the solenoid100d, the ring core80is fixed after welding the bottom portion14of the container10dand the flange portion65dof the stator core40. According to the solenoid100dof the fifth embodiment, since the container10dand the ring core80are fixed by welding, the stress applied to the previously welded portion16dcan be reduced in comparison with the case where the ring core80is fixed by caulking the opening portion17of the container10. Further, as compared with the case where the opening portion17of the container10is caulked to fix the ring core80, the gap between the ring core and the core stator does not need to be widened, so that the size of the coil20and the current driving the coil20can be reduced without lowering the magnetic efficiency.

Sixth Embodiment

In the solenoid100eof a sixth embodiment shown inFIG.8, the bottom portion14eof the container10eis separate from the side surface portion12e. In this respect, it is different from the solenoid100of the first embodiment. Regarding other configurations, the solenoid100eof the sixth embodiment and the solenoid100of the first embodiment are the same. The bottom portion14eis press-fitted into the side surface portion12e.

According to the solenoid100eof the sixth embodiment, the side surface portion12eand the bottom portion14eof the container10eare separate parts, the shape of the side surface portion12eis a substantially cylindrical shape, and the shape of the bottom portion14eis a disk shape. Therefore, both are simple in shape. Therefore, the core portion61eand the flange portion65ecan be manufactured separately, and the container10ecan be easily manufactured by press-fitting the bottom portion14einto the side surface portion12e. In the sixth embodiment, the bottom portion14eis press-fitted into the side surface portion12e, but the side surface portion12emay be caulked and fixed to the bottom portion14e.

Seventh Embodiment

In the solenoid100fof a seventh embodiment shown inFIG.9, the shaft accommodating portion50fof the stator core40fand the plunger accommodating portion60fare separate parts, and the shaft accommodating portion50fand the plunger accommodating portion60fare connected by a non-magnetic bridge member71. In this respect, it differs from the solenoid100of the first embodiment.

According to the solenoid100fof the seventh embodiment, since the shaft accommodating portion50fand the plunger accommodating portion60fare separated, the magnetic flux does not flow directly from the plunger accommodating portion60fto the shaft accommodating portion50fand flows from the plunger accommodating portion60fto the shaft accommodating portion50fvia the plunger30. As a result, more magnetic flux passes through the plunger30, so that magnetic efficiency can be improved.

Eighth Embodiment

In the solenoid100gof the eighth embodiment shown inFIG.10, the shaft accommodating portion50gof the stator core40gand the plunger accommodating portion60gare separate parts, and a space between the shaft accommodating portion50fand the plunger accommodating portion60fis filled with a non-magnetic bridge member72. In this respect, it differs from the solenoid100of the first embodiment.

According to the solenoid100gof the seventh embodiment, since the shaft accommodating portion50gand the plunger accommodating portion60gare separated, the magnetic flux does not flow directly from the plunger accommodating portion60gto the shaft accommodating portion50gand flows from the plunger accommodating portion60gto the shaft accommodating portion50gvia the plunger30. As a result, more magnetic flux passes through the plunger30, so that magnetic efficiency can be improved.

Ninth Embodiment

The solenoid100hof a ninth embodiment shown inFIG.11is different from the solenoid100of the first embodiment in that the shape of the ring core80his different. The ring core80his a substantially cylindrical magnetic material member, fastened to the first outer peripheral surface211of the sleeve210, arranged on the radial outside of the shaft accommodating portion50, and abuts on the container10inside the container10. In the present embodiment, the ring core80hincludes a first inner diameter part81, a second inner diameter part82having an inner diameter smaller than that of the first inner diameter part81, and a connecting surface83that connects the first inner diameter part81and the second inner diameter part82and is substantially parallel to the radial direction. In the present embodiment, the connecting surface83faces the end surface of the sleeve210on the spool valve200side on the direction AE side. In the present embodiment, the ring core80his press-fitted and fastened to the first outer peripheral surface211at the first inner diameter part81. Further, the ring core80his fitted to a second outer peripheral surface53at a second inner diameter part82. Further, in the present embodiment, the ring core80his in contact with the side surface portion12of the container10on the solenoid100side on the radial outer side and the direction AE side.

According to the solenoid100hof the ninth embodiment, a contact area between the ring core80hand the shaft accommodating portion50hcan be increased, so that the magnetic flux can be easily transferred between the shaft accommodating portion50hof the stator core40hand the side surface portion12of the container10.

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.