JP2004293763A - Electromagnetic driving device and flow control device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic driving device restricted in the sliding resistance, easy to secure accuracy in shape, and reduced in man-hours, and to provide a flow control device using the same. <P>SOLUTION: The peripheral wall of a plunger 40 is formed with a film part of diamond-like carbon. Thickness of the film part is thereby reduced, and an after-treatment such as grinding for improving shape accuracy of the plunger 40 after forming the film part is unnecessary. A process for improving hardness such as heating is unnecessary for the film part. Furthermore, sliding resistance between the film part and a stator core 30 is small. Coating for reducing the sliding resistance is therefore unnecessary. Improvement of durability with improvement of hardness of the film part and reduction of the sliding resistance are realized at the same time by one layer of the film part. Consequently, the man-hours can be reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electromagnetic drive device and a flow control device using the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known an electromagnetic driving device that forms a magnetic circuit by a mover and a stator and reciprocates the mover. As this electromagnetic drive device, for example, the mover is directly supported on the inner peripheral side of the housing portion of the stator, and the mover is moved to one side in the reciprocating direction by magnetic attraction force acting between the attracting portion of the stator and the mover. There is a device for suctioning to the surface (see Patent Document 1). In such an electromagnetic drive device, the outer peripheral wall of the mover or the inner peripheral wall of the stator is subjected to a plating treatment such as electroless NiP plating (see Patent Document 2).
[0003]
[Patent Document 1]
JP 2002-222710 A [Patent Document 2]
JP 2001-227669 A
[Problems to be solved by the invention]
By plating the outer peripheral wall of the mover or the inner peripheral wall of the stator with NiP, the hardness of the outer peripheral wall of the mover or the inner peripheral wall of the stator is increased, and the sliding generated between the mover and the housing portion of the stator is performed. Dynamic resistance has been reduced. However, in order to further improve the hardness and slidability of the NiP plating provided with the mover or the stator, a post-process such as heat treatment is required. Furthermore, the covering layer formed by plating has low shape accuracy. Therefore, a process for ensuring accuracy such as polishing is required between the formation of the plating and the heat treatment. Further, in order to further reduce the sliding resistance, it is necessary to further apply a coating such as a fluorine-containing resin on the surface of the NiP plating. As a result, there is a problem that the number of processing steps is increased.
[0005]
SUMMARY OF THE INVENTION It is an object of the present invention to provide an electromagnetic drive device in which sliding resistance is small, shape accuracy is easily ensured, and the number of processing steps is reduced, and a flow control device using the same.
[0006]
[Means for Solving the Problems]
According to the first or second aspect of the present invention, one of the outer peripheral wall of the mover and the inner peripheral wall of the housing portion is provided with a coating portion made of diamond-like carbon. By forming the coating portion with diamond-like carbon, hardness is increased, and sliding resistance between the mover and the housing portion is reduced. Also, diamond-like carbon is formed thinner on the mover or stator than in plating. Therefore, after forming the coating portion made of diamond-like carbon, post-processing such as polishing for improving the shape accuracy is not required. Further, diamond-like carbon has higher hardness and higher durability than plating. Therefore, heat treatment after the formation of the covering portion is unnecessary. Therefore, it is easy to secure the shape accuracy, and the number of processing steps can be reduced.
[0007]
In the invention according to claim 3 of the present invention, the mover has a nonmagnetic layer portion made of a nonmagnetic material between the mover and the coating portion. The non-magnetic layer is formed to prevent close contact between the mover and the stator. The thickness of the non-magnetic layer portion is set relatively large in order to reduce the attractive force in the direction perpendicular to the axis. When the non-magnetic layer portion is formed by plating, a process for increasing the shape accuracy is performed, and a film portion is formed by diamond-like carbon. This eliminates the need for processing to improve shape accuracy and heat treatment for hardening the surface after the formation of the coating. Therefore, it is easy to secure the shape accuracy, and the number of processing steps can be reduced.
[0008]
According to a fourth aspect of the present invention, there is provided the electromagnetic drive device according to the first, second or third aspect. Therefore, the controllability of the reciprocating position of the movable member that reciprocates with the mover is improved. Therefore, the flow rate or pressure of the fluid flowing through the fluid flow path can be controlled with high precision by the reciprocating movement of the movable member.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a flow control device according to an embodiment of the present invention. The flow control device 10 is, for example, a spool-type hydraulic control valve that controls the hydraulic pressure of hydraulic oil supplied to a hydraulic control device of an automatic transmission such as a vehicle.
The linear solenoid 20 as an electromagnetic drive includes a yoke 21, a stator core 30, a plunger 40, a coil 22, and the like. The yoke 21 and the stator core 30 are formed of a magnetic material, and constitute a stator. The plunger 40 constitutes a mover.
[0010]
The stator core 30 is formed in a cylindrical shape, and has a housing part 31, a suction part 32, and a magnetic resistance part 33. The accommodating portion 31 accommodates and supports the cylindrical plunger 40 coaxially on the inner peripheral side. A slight clearance is formed between the housing 31 of the stator core 30 and the plunger 40. Thus, the plunger 40 can reciprocally slide in the axial direction with the housing portion 31 of the stator core 30.
[0011]
The suction part 32 is disposed on one side of the accommodation part 31 in the axial direction. The attraction unit 32 generates a magnetic attraction force between the plunger 40 and the plunger 40 to attract the plunger 40 to one side in the reciprocating direction that is the axial direction thereof. A magnetic resistance portion 33 having a smaller thickness than the housing portion 31 and the suction portion 32 is formed between the housing portion 31 and the suction portion 32. The magnetic resistance part 33 restricts the flow of magnetic flux between the housing part 31 and the suction part 32.
[0012]
The yoke 21 is formed in a cylindrical shape, and houses the stator core 30, the coil 22, and the resin casing 23 on the inner peripheral side. The yoke 21 is fixed to the end of the housing 50 by caulking, thereby fixing the stator core 30, the coil 22, and the resin casing 23 between the yoke 21 and the housing 50.
[0013]
The resin casing 23 has a bobbin 24 and a fixing part 25. The bobbin 24 is formed in a cylindrical shape, and is fixed to the outer peripheral side of the accommodating portion 31 of the stator core 30, the suction portion 32, and the magnetic resistance portion 33. The coil 22 is wound around the outer periphery of the bobbin 24. The fixing portion 25 is fixed to the outer peripheral side of the coil 22 and covers the coil 22 together with the bobbin 24. The fixing portion 25 forms a connector (not shown) for supplying power to the coil 22.
[0014]
When current is supplied to the coil 22 from a terminal (not shown) that is electrically connected to the coil 22, a magnetic circuit is formed in the yoke 21, the stator core 30, and the plunger 40. As a result, magnetic flux flows through a magnetic circuit including the yoke 21, the stator core 30, and the plunger 40, and a magnetic attractive force is generated between the attraction portion 32 of the stator core 30 and the plunger 40. Accordingly, the plunger 40 moves in the reciprocating direction from the storage section 31 toward the suction section 32, that is, to the left in FIG.
[0015]
The housing 50 accommodates and supports a spool 60 as a movable member so as to be able to reciprocate in the axial direction. An input port 51, an output port 52, a feedback port 53, and a discharge port 54 are formed on the cylindrical peripheral wall of the housing 50 as fluid channels. Hydraulic oil supplied from a tank (not shown) flows into the input port 51. The output port 52 supplies hydraulic oil to an engagement device of an automatic transmission (not shown). The output port 52 and the feedback port 53 communicate with each other outside the flow control device 10, and a part of the operating oil flowing out of the output port 52 is introduced into the feedback port 53. The feedback chamber 55 communicates with the feedback port 53. The discharge port 54 discharges hydraulic oil to the tank.
[0016]
A first land 61, a second land 62, and a third land 63 are formed on the spool 60 in this order from the linear solenoid 20 side in the axial direction. The spool 60 is in contact with the end of the plunger 40 on the suction portion 32 side by a shaft 64 formed at one end in the axial direction. A spring 56 as an urging means is provided on the side of the spool 60 opposite to the plunger. The spring 56 urges the spool 60 in a direction opposite to the direction in which the plunger 40 is sucked by the suction portion 32, that is, rightward in FIG. Since the spool 60 is pressed against the plunger 40 by the urging force of the spring 56, the spool 60 reciprocates together with the plunger 40.
[0017]
The feedback chamber 55 is formed between the first land 61 and the second land 62. The first land 61 has a smaller outer diameter than the second land 62. Therefore, a force for pressing the spool 60 toward the side opposite to the plunger acts on the spool 60 by the hydraulic pressure of the feedback chamber 55. The reason for feeding back a part of the hydraulic pressure output in the flow control device is to prevent the output pressure from fluctuating due to the fluctuation of the supplied hydraulic pressure, that is, the input pressure. The spool 60 stops at a position where the force received by the hydraulic pressure of the feedback chamber 55, the force received by the plunger 40 sucked by the suction portion 32, and the urging force received from the spring 56 are balanced.
[0018]
The flow rate of the hydraulic oil flowing from the input port 51 to the output port 52 is determined by the seal length, which is the length of the overlapping portion between the inner peripheral wall 50a of the housing 50 and the outer peripheral wall of the second land 62. As the seal length becomes shorter, the flow rate of hydraulic oil flowing from the input port 51 to the output port 52 increases. On the other hand, as the seal length increases, the flow rate of the hydraulic oil flowing from the input port 51 to the output port 52 decreases. Similarly, the flow rate of the hydraulic oil flowing from the output port 52 to the discharge port 54 is determined by the seal length between the inner peripheral wall 50b of the housing 50 and the outer peripheral wall of the third land 63.
[0019]
When the spool 60 moves toward the spring 56, that is, to the left in FIG. 1, the seal length between the inner peripheral wall 50a and the second land 62 increases, and the seal length between the inner peripheral wall 50b and the third land 63 decreases. Therefore, the flow rate of the hydraulic oil flowing from the input port 51 to the output port 52 decreases, and the flow rate of the hydraulic oil flowing from the output port 52 to the discharge port 54 increases. As a result, the hydraulic pressure of the working oil flowing out of the output port 52 decreases. On the other hand, when the spool 60 moves toward the plunger 40, the seal length between the inner peripheral wall 50a and the second land 62 becomes shorter, and the seal length between the inner peripheral wall 50b and the third land 63 becomes longer. Therefore, the flow rate of the hydraulic oil flowing from the input port 51 to the output port 52 increases, and the flow rate of the hydraulic oil flowing from the output port 52 to the discharge port 54 decreases. As a result, the hydraulic pressure of the operating oil flowing out of the output port 52 increases.
[0020]
In the flow control device 10 described above, the force of the plunger 40 pushing the spool 60 toward the anti-linear solenoid changes by controlling the value of the current supplied to the coil 22. Thereby, the hydraulic pressure of the working oil flowing out of the output port 52 is adjusted. Specifically, when the value of the current supplied to the coil 22 is increased, the magnetic attraction generated between the attraction unit 32 and the plunger 40 increases in proportion to the current value. Therefore, the force of the plunger 40 pushing the spool 60 increases. When the force acting on the spool 60 from the plunger 40 by the magnetic attraction force, the urging force of the spring 56, and the force of pushing the spool 60 by the hydraulic pressure of the feedback chamber 55 are balanced, the spool 60 stops. Therefore, when the value of the current supplied to the coil 22 increases, the hydraulic pressure of the operating oil flowing out of the output port 52 decreases.
[0021]
Next, the plunger 40 will be described in detail.
The plunger 40 has a main body 41 formed of a magnetic material as shown in FIG. In the case of the present embodiment, the nonmagnetic layer 42 and the coating 43 are formed in the main body 41 of the plunger 40 in this order from the inner peripheral side. The coating 43 is made of diamond-like carbon, and is formed on at least the peripheral wall of the outer wall of the plunger 40. The coating 43 made of diamond-like carbon has a thickness of several μm. Therefore, it is formed uniformly on the outer peripheral wall of the plunger 40.
[0022]
In the case of the present embodiment, a nonmagnetic layer 42 is formed between the main body 41 and the coating 43. The non-magnetic layer portion 42 is formed of a non-magnetic metal or non-metal. The nonmagnetic layer 42 may be formed directly on the main body 41 by, for example, plating, coating, or the like, or may be formed by attaching a cup-shaped nonmagnetic member to the main body 41. The non-magnetic layer portion 42 prevents a magnetic flux from being short-circuited between the housing portion 31 and the suction portion 32 via the surface of the plunger 40. By forming the nonmagnetic layer 42, the magnetic attraction between the plunger 40 and the housing 31 of the stator core 30 is reduced. Thereby, a magnetic attraction force is generated between the plunger 40 and the attraction portion 32 of the stator core 30 by a magnetic circuit formed in the yoke 21, the stator core 30, and the plunger 40. As a result, the plunger 40 is sucked by the suction portion 32 of the stator core 30.
[0023]
When the coating 43 made of diamond-like carbon is formed on the outer peripheral wall of the plunger 40, the nonmagnetic layer 42 is formed on the main body 41 prior to the formation of the coating 43. After the non-magnetic layer portion 42 is formed on the main body portion 41 by, for example, plating, the non-magnetic layer portion 42 is subjected to a processing such as polishing, for example, to secure the shape accuracy of the plunger 40. When the processing of the plunger 40 is completed, the coating portion 43 is formed on the surface thereof.
[0024]
For example, in the case of a conventional coating portion to which electroless NiP plating is applied, heat treatment or the like is required after plating in order to increase the hardness of the coating portion. The coating formed by plating has a thickness of about several tens of μm. Therefore, in order to secure the shape accuracy of the plunger 40, post-processing such as polishing is required. Further, since the coating formed by plating has a relatively high sliding resistance, it is coated with, for example, a fluorine-containing resin after a post-treatment such as polishing.
[0025]
On the other hand, in the case of the present embodiment in which the coating 43 is formed of diamond-like carbon, the coating 43 is as thin as several μm as described above. Therefore, after the formation of the coating portion 43, post-processing such as polishing is not necessary to secure the shape accuracy of the plunger 40. Further, since the coating 43 made of diamond-like carbon forms a hard, uniform and dense layer, the sliding resistance between the coating 43 and the housing 31 of the stator core 30 is small.
[0026]
In the case of the flow control device 10 according to one embodiment, as shown in FIGS. 3 and 4, the relationship between the output hydraulic pressure and the current applied to the coil 22 is smaller than that in the case where the coating is formed by the conventional electroless NiP plating. Hysteresis is small. In addition, by reducing the sliding resistance, the response period from application of a current to the coil 22 to output of a predetermined oil pressure is also reduced as shown in FIG. This is because the sliding resistance between the plunger 40 and the stator core 30 is reduced by forming the coating 43 made of diamond-like carbon on the plunger 40.
[0027]
According to the flow control device described above, by forming the coating 43 made of diamond-like carbon on the outer peripheral wall of the plunger 40, the sliding resistance between the plunger 40 and the housing 31 of the stator core 30 is reduced. By reducing the sliding resistance, the correlation between the value of the current supplied to the coil 22 and the position of the plunger 40 approaches a proportional relationship. Therefore, control of the reciprocating movement positions of the plunger 40 and the spool 60 is facilitated, controllability can be improved, hysteresis can be reduced, and responsiveness can be improved.
[0028]
In one embodiment, the coating 43 is formed from diamond-like carbon. Therefore, the thickness of the coating portion 43 is small, and it is not necessary to perform post-processing such as polishing in order to increase the shape accuracy of the plunger 40 after the coating portion 43 is formed. The coating 43 made of diamond-like carbon has a higher hardness than conventional plating. Therefore, a process for increasing the hardness such as a heat treatment is not required. Further, the coating 43 made of diamond-like carbon has a small sliding resistance with the stator core 30. Therefore, a coating for reducing sliding resistance is not required. As described above, by forming the coating portion 43 from diamond-like carbon, the durability of the coating portion 43 is improved and the sliding resistance is reduced, while the hardness of the coating portion 43 is reduced. can do. Therefore, the number of processing steps can be reduced.
[0029]
In the embodiment described above, an example in which the coating 43 made of diamond-like carbon is formed on the outer peripheral wall of the plunger 40 has been described. However, a coating made of diamond-like carbon may be formed not on the outer peripheral wall of the plunger 40 but on the inner peripheral wall of the housing portion 31 of the stator core 30 as the stator.
Further, in the above-described embodiment, the example in which the electromagnetic drive device of the present invention is applied to the electromagnetic drive unit of the flow control device has been described, but the electromagnetic drive device of the present invention is applied to the electromagnetic drive unit of a device other than the flow control device. May be applied.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a flow control device to which an electromagnetic drive device according to an embodiment of the present invention is applied.
FIG. 2 is a sectional view of the plunger taken along line II-II in FIG.
FIG. 3 is a schematic diagram showing a relationship between a current and an output hydraulic pressure in the flow control device to which the electromagnetic drive device according to the embodiment of the present invention is applied, and showing a case where the output hydraulic pressure decreases as the current increases. It is.
FIG. 4 is a schematic diagram showing a relationship between a current and an output hydraulic pressure in the flow control device to which the electromagnetic driving device according to the embodiment of the present invention is applied, and showing a case where the output hydraulic pressure increases with an increase in the current; It is.
FIG. 5 is a schematic diagram showing a relationship between a response period after energization of a coil and an output oil pressure in a flow control device to which an electromagnetic drive device according to an embodiment of the present invention is applied.
[Explanation of symbols]
10 Flow control device 20 Linear solenoid (electromagnetic drive)
21 Yoke (stator)
22 coil 30 stator core (stator)
31 accommodation part 32 suction part 40 plunger (movable element)
42 Non-magnetic layer 43 Coating 50 Housing 51 Input port (fluid flow path)
52 Output port (fluid flow path)
53 Feedback port (fluid flow path)
54 Discharge port (fluid flow path)
56 spring (biasing means)
60 spool (movable member)

Claims (4)

Mover,
A magnetic circuit is formed together with the mover, an accommodating portion for accommodating the mover reciprocally on the inner peripheral side, and a magnetic attraction force for attracting the mover to one side in the reciprocal movement direction, A stator having a suction part generated therebetween,
A coating portion formed on one of the outer peripheral wall of the mover and the inner peripheral wall of the housing portion and made of diamond-like carbon,
An electromagnetic drive device comprising: Mover,
A magnetic circuit is formed together with the mover, an accommodating portion for accommodating the mover reciprocally on the inner peripheral side, and a magnetic attraction force for attracting the mover to one side in the reciprocal movement direction, A stator having a suction part generated therebetween,
A coating portion formed on the outer peripheral wall of the mover and made of diamond-like carbon,
An electromagnetic drive device comprising: 3. The electromagnetic drive device according to claim 2, wherein the mover has a nonmagnetic layer made of a nonmagnetic material between the mover and the coating. A housing having a plurality of fluid flow paths penetrating the cylindrical peripheral wall,
An electromagnetic drive device according to claim 1, 2, or 3,
A movable member that controls the flow rate of the fluid flowing through the fluid flow path by reciprocating with the mover,
Urging means for urging the movable member in a direction opposite to a direction in which the mover is sucked by the suction portion;
A flow control device comprising:

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