JPH062232U - Electromagnetic rotation sensor - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent output signals from being erroneously prevented by preventing short-circuiting of the output terminal due to rainwater. [Structure] The rectangular concave step portion 2 is provided on the upper end side of the inner circumference of the housing cylinder portion 27.
9 is provided, and the rectangular concave step portion 29 and the step portion 3 of the iron core member 30 are provided.
0B and the small diameter portion 30C form a concave groove G, and an insulating resin material is flown into the concave groove G during injection molding of the casing 21 to form a seal convex portion 31 to form the seal convex portion 3
1 denotes the rectangular concave step portion 29 and the step portion 30 of the iron core member 30.
B, the small diameter portion 30C is brought into liquid-tight contact. Therefore, the outer fitting hole 25A of the closing portion 25 and the coil bobbin main body 28
Rainwater or the like from the gap between the small diameter portion 10B of the coil bobbin main body 28 and the small diameter portion 10B of the core member 10.
The coil bobbin 2 through the gap between
6 Even if it penetrates into the inner peripheral side, this rainwater or the like will be exposed to the seal projection 3
Can be sealed by 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electromagnetic rotation sensor suitable for use in, for example, a crank angle sensor that detects the rotation speed of an automobile engine.

[0002]

[Prior art]

 5 and 6 show a conventional electromagnetic rotation sensor.

In the figure, reference numeral 1 denotes a casing of an electromagnetic rotation sensor formed by injection-molding a hard insulating resin material, and the casing 1 is formed in a cylindrical shape with a lid extending upward and downward. The casing main body 2, a coil bobbin accommodating portion 3 formed inside the casing main body 2, and a connector connecting portion 4 located on the upper end side of the casing main body 2 and projecting radially outward. On the lower end side of the casing body 2, a ring-shaped closing portion 5 is formed which projects inward in the radial direction and closes the coil bobbin accommodating portion 3. The inner peripheral end of the closing portion 5 has a core member described later. The small-diameter portion 10B of 10 is fitted in a liquid-tight manner to form an outer fitting hole 5A for preventing rainwater and the like from entering from the outside.

Reference numeral 6 denotes a coil bobbin which is provided in the coil bobbin accommodating portion 3 and is formed by injection molding a hard insulating resin material. The coil bobbin 6 is located at the upper end side and moves upward and downward. It is composed of an accommodating cylinder part 7 as a magnet accommodating part formed in an elongated cylindrical shape, and a coil bobbin main body 8 as a coil winding part integrally formed at the lower end side of the accommodating cylinder part 7, A terminal rod 14 which is located on the left side in the drawing and is described later is disposed in the housing cylinder portion 7 so as to penetrate upward and downward. The coil bobbin main body 8 has an upper flange portion 8A formed so as to radially inwardly project from a lower end side of the accommodating cylinder portion 7, and extends downward from an inner peripheral end side of the upper flange portion 8A. Is a through-hole 8B, and a lower flange portion 8D radially outwardly protruding from the lower end side of the winding tubular portion 8C. The outer peripheral side of the winding tubular portion 8C. A detection coil 12 to be described later is wound around this.

Reference numeral 9 is a permanent magnet provided in the housing cylinder portion 7 and formed in a short columnar shape. Reference numeral 10 is a core member formed in a stepped columnar shape by a magnetic material such as electromagnetic soft iron. The member 10 is located on the base end side, and the back side is in contact with the lower end surface side of the permanent magnet 9 and a large diameter portion 10A, which extends coaxially from the large diameter portion 10A, and a through hole 8B of the coil bobbin main body 8 is formed. The core member 10 has a small diameter portion 10B inserted therein, and the core member 10 has a large diameter portion 10A disposed inside the accommodating tubular portion 7 and a lower surface side of the large diameter portion 10A disposed on an upper side collar of the coil bobbin main body 8. The tip end surface 10C of the small-diameter portion 10B slightly protrudes to the outside through the outer fitting hole 5A of the closing portion 5 by abutting on the upper surface side of the portion 8A and performing positioning. The core member 10 is so positioned that the tip surface 10C of the small-diameter portion 10B is positioned on the outer peripheral side of a rotary plate (not shown) formed of a magnetic material in the shape of a toothed disc.

Reference numeral 11 denotes an iron core member that is provided inside the housing cylinder portion 7 and is in contact with the upper end surface side of the permanent magnet 9, and the iron core member 11 is a long circle made of a magnetic material such as electromagnetic soft iron. It is formed in a columnar shape, which increases the magnetic flux density of the permanent magnet 9.

Reference numeral 12 denotes a detection coil which is located on the outer peripheral side of the small diameter portion 10B of the core member 10 and which is provided by winding a winding around the outer periphery of the winding tubular portion 8C of the coil bobbin main body 8. The detection coil 12 is It is connected to a control unit (neither is shown) via an output terminal 13, a lead wire, etc., which will be described later. Then, the detection coil 12 generates an induced electromotive force by an electromagnetic induction action when the rotating plate made of a magnetic material rotates and the magnetic flux from the permanent magnet 9 passing through the core member 10 changes. Is output to the control unit as a rotation signal of the rotating plate.

Reference numeral 13 denotes a pair of output terminals (only one of which is shown) formed from a conductive material in a substantially L shape, which is provided from the connector connecting portion 4 to the accommodating cylinder portion 7. The output terminal 13 is , A terminal rod 14 which is located on the outer peripheral side of the accommodating cylinder portion 7 and extends upward and downward, the upper end side of which projects from the upper end surface of the accommodating cylinder portion 7, and the base end side of which is the terminal rod 14. A pair of output terminals 15 (only one of which is shown) is formed as a connecting portion 15A connected to the upper end side, and the tip end side thereof extends radially outward from the upper end side of the connecting portion 15A and projects into the connector connecting portion 4. The lower end side of the terminal rod 14 is connected to the detection coil 12.

The electromagnetic rotation sensor according to the prior art has the above-mentioned configuration, and the manufacturing procedure thereof will be described next.

First, the coil bobbin 6 is formed by injection molding while the terminal rod 14 is positioned on the outer peripheral side of the housing cylinder 7. Then, the core member 10, the permanent magnet 9 and the iron core member 11 are sequentially inserted into the housing cylinder portion 7 of the coil bobbin 6, and the detection coil 12 is wound around the winding cylinder portion 8C of the coil bobbin body 8 and its winding end is wound. The part side is connected to the lower end side of the terminal rod 14. Next, after mounting the output terminal 15 on the upper end side of the terminal rod 14, in this state, it is positioned in the molding die (not shown) of the casing 1, and the molten insulating resin material is pressurized in the molding die. While casting, the casing 1 is molded to manufacture an electromagnetic rotation sensor.

Next, when the electromagnetic rotation sensor manufactured as described above is used for a crank angle sensor of an automobile engine, a rotating plate is integrally formed with a crankshaft (not shown) by starting the engine. When rotating, the teeth of the rotating plate made of a magnetic material gradually come closer to and away from the front end surface 10C of the core member 10, so that the magnetic flux that passes through the core member 10 from the permanent magnet 9 changes and electromagnetic induction An induced electromotive force is generated in the detection coil 12 by the action. Then, this electromotive force is output to the control unit via the output terminal 13 etc. as a detection signal that increases / decreases according to the approach and separation of the teeth of the rotating plate, and is used as a crank angle signal for detecting the engine speed. .

[0012]

[Problems to be solved by the device]

 By the way, in the above-described electromagnetic rotation sensor according to the conventional technique, the casing 1 is formed by injection molding so as to enclose the permanent magnet 9, the core member 10, the detection coil 12 and the like in the coil bobbin 6 in a state of being assembled. The outer fitting hole 5A of the closing portion 5 and the small diameter portion 10B of the core member 10 are brought into liquid-tight contact with each other to prevent rainwater or the like from entering the casing 1 from the outside. .

However, since the closed portion 5 is formed thin, and the electromagnetic rotation sensor is attached to a place such as an engine that is constantly vibrated, as shown in FIG. Due to this, a gap is likely to be formed between the outer fitting hole 5A and the small diameter portion 10B, and rainwater from this gap allows a gap S1 between the through hole 8B of the coil bobbin body 8 and the small diameter portion 10B of the core member 10, the permanent magnet 9, the iron core member. 11 may penetrate into the upper end side of the coil bobbin 6 through the gap S2 between the inner peripheral side of the housing cylinder portion 7 and reach the output terminals 13 through the upper end surface side of the housing cylinder portion 7. . As a result, rainwater causes a short circuit between the output terminals 13, and this short circuit causes an erroneous signal to be output, resulting in a significant decrease in reliability.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides an electromagnetic rotation sensor capable of preventing a short signal from being generated by rainwater or the like and preventing an erroneous signal from being output. The purpose is to do.

[0015]

[Means for Solving the Problems]

 The feature of the configuration adopted by the present invention to solve the above-mentioned problem is that an annular groove is provided on the inner peripheral side of the magnet housing portion of the coil bobbin from the opening end side of the magnet housing portion toward the other side. This is because an annular seal protrusion was provided integrally with the casing in the groove.

[0016]

[Action]

 With the above configuration, even if rainwater or the like enters between the coil bobbin accommodating portion of the casing and the core member, this rainwater is blocked by the seal convex portion formed on the upper end side of the coil bobbin magnet accommodating portion, and is output to the output terminal side. Ingress is prevented.

[0017]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those of the prior art shown in FIGS. 5 and 6 described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 21 denotes a casing according to this embodiment, which is substantially the same as the casing 1 described in the prior art. The casing main body 22, the coil bobbin accommodating portion 23, the connector connecting portion 24 and the outer fitting are provided. The coil bobbin accommodating portion 23 is provided with a seal convex portion 31 which will be described later, although it is composed of the closing portion 25 having the hole 25A.

Reference numeral 26 denotes a coil bobbin according to this embodiment, which is provided in the coil bobbin accommodating portion 23 and is formed by injection-molding a hard insulating resin material. The coil bobbin 26 is the coil bobbin described in the prior art. In the same manner as 6, the housing cylinder portion 27, which is located at the upper end side and extends upward and downward, is formed into a cylindrical shape and serves as a magnet housing portion, and is integrally formed at the lower end side of the housing cylinder portion 27. The coil bobbin main body 28 as a coil winding portion including the upper collar portion 28A, the through hole 28B, the winding tubular portion 28C, and the lower collar portion 28D is roughly configured, but A rectangular concave step portion 29, which will be described later, is formed on the inner peripheral side.

Reference numeral 29 denotes a rectangular concave stepped portion that is coaxially located on the inner peripheral side of the housing cylinder portion 27 and that forms a concave groove G together with a stepped portion 30B and a small diameter portion 30C of an iron core member 30 described later. As shown in FIG. 2, the rectangular concave step portion 29 is located on the upper end side of the accommodating cylinder portion 27, opens upward, and has a square shape with a side having the same dimension as the inner diameter of the accommodating cylinder portion 27. Has been formed.

Reference numeral 30 denotes an iron core member according to the present embodiment, which is located in the housing cylinder portion 27 and is made of a magnetic material such as electromagnetic soft iron. The lower end side of the iron core member 30 contacts the upper end side of the permanent magnet 9. A large diameter portion 30A disposed in contact with the large diameter portion 30A and a step portion 30B formed on the upper end side of the large diameter portion 30A extend upward, and a small diameter portion 30C formed to have a smaller diameter than the large diameter portion 30A. Is formed into a stepped columnar shape, and a seal protrusion 31 is in liquid-tight contact with the outer peripheral side of the small diameter portion 30C.

Reference numeral 31 denotes a seal convex portion formed so as to project downward from the upper end side of the coil bobbin accommodating portion 23. The seal convex portion 31 has a rectangular concave step portion 29 on the outer peripheral side as shown in FIG. It has a square shape, and the inner peripheral side is formed into a cylindrical shape by the small diameter portion 30C of the iron core member 30 to form a cylindrical space. The sealing convex portion 31 has an insulating resin material injected into the concave groove G formed by the rectangular concave step portion 29, the step portion 30B, and the small diameter portion 30C during injection molding of the casing 21. Thus, the casing 21 is integrally formed with the rectangular concave step portion 29, the step portion 30B, and the small diameter portion 30C while being in liquid-tight contact with each other.

The electromagnetic rotation sensor according to the present embodiment has the above-mentioned configuration, and its basic operation is not particularly different from that according to the prior art.

However, in this embodiment, the rectangular concave step portion 29 is provided on the inner peripheral upper end side of the accommodating cylinder portion 27, and the rectangular concave step portion 29, the step portion 30B of the iron core member 30, and the small diameter portion 30C are provided. By forming a concave groove G and injecting an insulating resin material into the concave groove G during injection molding of the casing 21 to form a seal convex portion 31, the seal convex portion 31 is formed into the rectangular concave step portion 29. It is configured such that it is brought into liquid-tight contact with the stepped portion 30B and the small diameter portion 30C of the iron core member 30. Therefore, as shown in FIG. 4, a gap is formed between the outer fitting hole 25A of the closing portion 25 and the small diameter portion 10B of the coil bobbin main body 28, and rainwater is supplied from this gap to the through hole 28B of the coil bobbin main body 28 and the core member. Even if it penetrates through the gap S 1 between the small-diameter portion 10B of 10 and the permanent magnet 9, the large-diameter portion 30A of the iron core member 30 and the inner peripheral side of the accommodating tubular portion 27, the seal protrusion 31 causes It is possible to reliably prevent the rainwater from reaching each output terminal 13.

Thus, according to the present embodiment, the seal convex portion provided so as to come into liquid-tight contact with the concave groove G formed by the rectangular concave step portion 29, the step portion 30B of the iron core member 30, and the small diameter portion 30C. 31 can prevent rainwater from entering the output terminals 13 side, so that it can be surely prevented that each output terminal 13 is short-circuited and that an erroneous signal is not output and reliability is greatly improved. Can be improved.

Although the small diameter portion 30C of the iron core member 30 is formed in a cylindrical shape having a smaller diameter than the large diameter portion 30A in the above embodiment, the present invention is not limited to this, and for example, the small diameter portion is used. 30C may be formed in other shapes such as a quadrangle and an ellipse, and is not limited to this as long as it can form a predetermined gap with the inner peripheral side of the housing tubular portion 27.

Further, in the above embodiment, the rectangular concave step portion 29 is described as being formed in a square shape by the side having the same size as the inner diameter of the accommodating cylinder portion 27, but instead of this, for example, a rectangular concave portion is formed. The step portion 29 may be formed in another shape such as a circular shape or a hexagonal shape.

Further, in the above-described embodiment, the rectangular concave step portion 29 is formed on the upper end side of the inner circumference of the accommodating cylinder portion 27, and the small diameter portion 30C is formed on the upper end side of the iron core member 30 via the step portion 30B. Thus, the concave groove G is formed from the rectangular concave step portion 29, the step portion 30B, and the small diameter portion 30C, but the present invention is not limited to this, and the rectangular concave step portion 29 is accommodated, for example. Alternatively, the core portion 30 may be formed to have a larger diameter than the inner diameter of the tubular portion 27, and the iron core member 30 may be formed into a columnar shape having no step so that the concave groove portion G is formed by the concave step portion 29 and the iron core member 30. In addition, the concave groove G is formed by the inner peripheral surface of the accommodating cylinder portion 27 and the step portion 30B and the small diameter portion 30C of the iron core member 30 without forming the rectangular concave step portion 29 in the accommodating cylinder portion 27. May be.

Further, in the above-described embodiment, the crank angle sensor has been described as an example of the electromagnetic type rotation sensor, but the present invention is not limited to this, and various types of sensors such as a rotation sensor for detecting the number of rotations of a wheel may be used. It can also be applied to an electromagnetic rotation sensor.

[0030]

[Effect of device]

 As described above in detail, according to the present invention, an annular groove is formed on the inner peripheral side of the magnet containing portion of the coil bobbin from the opening end side of the magnet containing portion toward the other side, and the annular groove is formed at the time of injection molding of the casing. Since the annular seal projection is provided in the groove integrally with the casing, even if rainwater or the like enters between the coil bobbin accommodating part of the casing and the core member, this rainwater will not be absorbed by the seal projection. It can be shut off, rainwater can be reliably prevented from entering the output terminal side and short-circuiting at the output terminal, and the output of false signals can be prevented, improving the reliability of the electromagnetic rotation sensor. be able to.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an electromagnetic rotation sensor according to an embodiment of the present invention.

FIG. 2 is an external perspective view showing, in an enlarged manner, a state in which an iron core member is inserted in the housing cylinder portion in FIG.

FIG. 3 is an enlarged transverse sectional view of an essential part of the electromagnetic rotation sensor in FIG. 1 viewed from the direction of arrow III-III.

FIG. 4 is an enlarged vertical sectional view of an essential part showing a state in which each gap is formed on the inner peripheral side of the coil bobbin in FIG.

FIG. 5 is a vertical sectional view showing an electromagnetic rotation sensor according to a conventional technique.

6 is an enlarged vertical cross-sectional view of an essential part showing a state in which gaps are formed on the inner peripheral side of the coil bobbin in FIG.

[Explanation of symbols]

 9 permanent magnet 10 core member 12 detection coil 13 output terminal 21 casing 23 coil bobbin accommodating part 24 connector connecting part 26 coil bobbin 27 accommodating cylinder part (magnet accommodating part) 28 coil bobbin body (coil winding part) 29 rectangular concave step part 30 iron core Member 30B Step portion 30C Small diameter portion 31 Seal convex portion G concave groove

Claims (1)

[Scope of utility model registration request] 1. A casing having one end serving as a connector connecting portion and the other end serving as a coil bobbin accommodating portion, and a magnet accommodating portion provided in the coil bobbin accommodating portion of the casing and having one end opening toward one side and the other end. A coil bobbin whose side is a coil winding portion, a permanent magnet provided in a magnet accommodating portion of the coil bobbin, a proximal end of the coil bobbin abutting against the permanent magnet in the magnet accommodating portion of the coil bobbin, and a distal end side of the coil bobbin. Core member protruding from the coil bobbin accommodating portion via the coil winding portion, a detection coil wound around the coil winding portion of the coil bobbin, one end side connected to the detection coil, and the other end side magnet of the coil bobbin. In an electromagnetic type rotation sensor consisting of an output terminal projecting outside from the connector connecting part through the housing part,
An annular concave groove is provided on the inner peripheral side of the magnet containing portion of the coil bobbin from the opening end side of the magnet containing portion toward the other side, and an annular seal convex portion is integrally formed with the casing in the concave groove. An electromagnetic rotation sensor characterized by being provided.