JPH0894656A - Electromagnetic angle-of-rotation sensor - Google Patents

Abstract

PURPOSE: To prevent an iron-based metal component at the inside of a sensor from becoming rusty when it is flooded and to prevent, with high reliability, water from creeping into an output terminal part. CONSTITUTION: A coil bobbin 11 which is buried and installed in a casing is provided with a magnet housing part 13 in which a permanent magnet 20 and a magnetism-gathering body 21 are housed and with a coil winding part 14 on which a detection coil 15 is wound. Both parts are continued integrally via a boundary wall part 12 which serves both as the bottom of the magnet housing part 13 and as a flange on the side of the magnet housing part 13 for the coil winding part 14. An iron core 16 in which a large-diameter part 18 has been formed integrally at one end of a small-diameter shaft part 17 is arranged inside the magnet housing part 13, and the small-diameter shaft part 17 is installed so as to be passed through a central hole 14b in the coil winding part 14. By this precondition, a ringed elastic seal material 19 which can prevent water from creeping to the inside of an output terminal 22 and which can be deformed elastically is sandwiched and installed between the boundary wall part 12 and the large-diameter part 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used, for example, to detect the crank angle position of each cylinder in order to determine the ignition timing and fuel injection timing of an internal combustion engine such as an engine for automobiles. The present invention relates to an electromagnetic rotation angle sensor, and more particularly, to an electromagnetic rotation angle sensor that takes measures to prevent water from entering the inside of the sensor due to water exposure.

[0002]

2. Description of the Related Art In an electromagnetic rotation angle sensor for detecting a crank angle position, a magnet accommodating portion is provided on a synthetic resin coil bobbin to which a pair of output terminals are connected and a detection coil is attached. A permanent magnet and a magnetic flux collector for collecting magnetic flux are accommodated in the accommodating portion, and a coil winding portion of a coil bobbin to which a detection coil is attached is provided by penetrating a core iron core that is in contact with the permanent magnet, and the above-mentioned parts are inserted. Some of them are embedded in a synthetic resin casing by molding, and the end of the core iron core opposite to the permanent magnet is exposed to the outside of the casing.

In this type of rotation angle sensor, a gap may occur between the core iron core and the contact surfaces of the synthetic resin casing and the coil bobbin which are in contact with the core iron core due to the difference in thermal expansion of these dissimilar materials. Therefore, when the rotation angle sensor is exposed to water, water may enter the inside of the sensor through the gap, thereby short-circuiting the output terminal and outputting an erroneous signal.

Therefore, an electromagnetic type rotation angle sensor, which has taken measures to prevent the output of such an erroneous signal, is disclosed in
It is known from Japanese Patent No. 2232. FIG. 3 shows the electromagnetic rotation angle sensor described in the above publication, in which 1 is an output terminal, 2 is a detection coil, 3 is a coil bobbin, and 3 is a coil bobbin.
a is a magnet accommodating portion, 3b is a coil winding portion, 4 is a permanent magnet,
Reference numeral 5 is a magnetism collector, 6 is a core iron core, and 7 is a casing.

By providing a step portion circumferentially continuous on the side of the magnetism collector 5 opposite to the permanent magnet 4, the magnet accommodating portion 3 is provided between the inner peripheral surface of the magnet accommodating portion 3a and the step portion.
An annular concave groove 8 is formed from the opening end side of a toward the other end side, and an annular seal convex portion 9 with which the concave groove 8 is filled is integrally provided in the casing 7. The seal protrusion 9 is formed by injection molding of the casing 7.

With this structure, even if water penetrates into the inside of the sensor through the above-mentioned gap due to exposure to water, the water can be sealed by the sealing projections 9, so that the invaded water is prevented from reaching the output terminal 1. it can. Thereby, the output of an erroneous signal due to a short circuit of the output terminal 1 can be prevented.

[0007]

However, the permanent magnet 4 and the magnetism collector 5 superposed on the permanent magnet 4 are arranged in the intrusion path through which the water invading the inside of the sensor reaches the seal projection 9. Since the permanent magnet 4 and the magnetism collector 5 are both formed of iron-based metal, they are exposed to water that has penetrated into the inside of the sensor to cause rusting, thereby impairing the product life. is there.

In addition, since the seal projection 9 is integrally molded in the casing 7 made of synthetic resin, the seal projection 9 and the magnet collector 5 and the magnet accommodating portion 3a of the coil bobbin 3 are different in material from each other. There are still differences in thermal expansion.
Therefore, it is undeniable that a gap may be created between the seal protrusion 9 and the magnet housing 3a. Therefore, there is a problem in that high reliability cannot be expected in preventing water from entering the output terminal portion.

An object of the present invention is to obtain an electromagnetic rotation angle sensor which can prevent rusting of iron-based metal parts inside the sensor due to exposure to water and highly reliably prevent water from entering the output terminal portion. Especially.

[0010]

According to the present invention, one end side constitutes a magnet accommodating portion and the other end side constitutes a coil winding portion, and the magnet accommodating portion and the coil winding portion form the magnet accommodating portion. A coil bobbin integrally connected through a boundary wall portion that also serves as a bottom and a flange of the coil winding portion on the side of the magnet housing portion, a detection coil wound around and attached to the coil winding portion, and a small diameter shaft portion. A core portion provided integrally with a large-diameter portion at one end of the core-diameter, the large-diameter portion being arranged in the magnet housing portion, and the small-diameter shaft portion being provided in the center hole of the coil winding portion. A permanent magnet which is in contact with the large diameter portion and is accommodated in the magnet accommodating portion; a magnetism collector which is in contact with the permanent magnet from a side opposite to the large diameter portion and is accommodated in the magnet accommodating portion; Is installed outside the A pair of output terminals connected to the coil, and a casing made of synthetic resin in which the other ends of the output terminals and the other end of the small-diameter shaft part are exposed and the other parts are embedded. It is premised on an electromagnetic rotation angle sensor comprising:

In order to achieve the above object, an annular elastic seal material capable of elastic deformation is sandwiched between the boundary wall portion and the large diameter portion of the core iron core.

[0012]

In the electromagnetic rotation angle sensor having the above-described structure, the water that enters the inside of the sensor when it is exposed to water first passes through the gap generated between the small-diameter shaft portion of the core iron core and the coil winding portion of the coil bobbin. Then, it tries to reach the output terminal side through the inside of the coil bobbin magnet housing.

However, an annular elastic sealing material is sandwiched between the boundary wall portion between the coil winding portion and the magnet accommodating portion of the coil bobbin and the large diameter portion arranged in the magnet accommodating portion of the core iron core. Since it is provided, this sealing material blocks water that has entered the inside of the sensor, and prevents water from entering the boundary wall portion first.

As a result, the permanent magnet and the magnetism collector which are the iron-based metal parts housed inside the magnet housing are not exposed to the invading water, and the invading water can reach the output terminal side. Absent. Since the elastic seal material forming the waterproof seal as described above can be elastically deformed, even if the distance between the boundary wall portion and the large diameter portion changes due to the difference in thermal expansion, the waterproof sealing performance can be maintained following the change. .

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 are views showing the configuration of an electromagnetic rotation angle sensor for detecting a crank angle of an internal combustion engine according to an embodiment of the present invention, and reference numeral 11 in these drawings.
The coil bobbin made of a synthetic resin integrally-molded product shown in FIG.
3 and a coil winding portion 14 continuous to the other end side. The magnet housing portion 13 has a bottomed cylindrical shape with the boundary wall portion 12 as the bottom.

The coil winding portion 14 uses the boundary wall portion 12 as one flange and also has the other flange 14a opposed thereto. Both ends of the center hole 14b provided through the central shaft portion of the coil winding portion 14 are
The boundary wall portion 12 and the flange 14a are opened at the central portions thereof, respectively. A detection coil 15 is wound around and attached to the central shaft portion of the coil winding portion 14.

Reference numeral 16 in FIGS. 1 and 2 denotes a core iron core made of an iron-based metal, which is formed by integrally providing a large diameter portion 18 at one end of a small diameter shaft portion 17. The small diameter shaft portion 17 is longer than the central hole 14b, and the large diameter portion 18 is the boundary wall portion 1.
It is slightly smaller than 2. The core iron core 16 has a small-diameter shaft portion 17 at the head, and a core hole 14 is formed from the magnet housing portion 13 side.
It is passed through a.

An annular elastic seal material 19 is sandwiched between the large-diameter portion 18 of the core iron core 16 and the boundary wall portion 12 of the coil bobbin 11. The sealing material 19 is made of rubber or liquid packing. The outer peripheral surface 19a of the elastic seal material 19 is elastically brought into close contact with the inner peripheral surface of the magnet housing portion 13 on the boundary wall portion 12 side, and the central hole 19b of the elastic seal material 19 through which the small diameter shaft portion 17 is passed. Is also elastically brought into close contact with the small-diameter shaft portion 17. Further, one surface of the elastic sealing material 19 is elastically brought into close contact with the boundary wall portion 12, and the other surface is brought into elastic close contact with the large diameter portion 18.

A permanent magnet 20 made of iron-based metal is housed in the magnet housing portion 13 in contact with the large diameter portion 18. The magnet 20 has a diameter slightly smaller than the inner diameter of the magnet housing 13 and is magnetized in the thickness direction. Further, a magnet collector 21 having the same diameter as the permanent magnet 20 is housed in the magnet housing portion 13. The magnetism collector 21 made of iron-based metal is used to collect magnetic flux, and the large-diameter portion 18 of the permanent magnet 20 is used.
The surface contact is provided from the opposite side.

A pair of output terminals 22 (only one is shown) are arranged outside the magnet housing portion 13. These terminals 22 are made of thin and highly conductive metal rods bent in an L shape, and one end 22a side thereof is the magnet accommodating portion 1.
It is provided so as to be attached to the outside of 3. The coil end of the detection coil 15 is connected to the one end 22a, and these are electrically connected.

The above-mentioned components, that is, the coil bobbin 11, the detection coil 15, the core iron core 16, the elastic sealing material 19, the permanent magnet 20, the magnetic collector 21, and the pair of output terminals 2.
2 is embedded by insert molding in a casing 23 made of synthetic resin. At the central portion of the flange cover portion 23a that covers the flange 14a of the casing 23, the end of the small-diameter shaft portion 17 of the core iron core 16 opposite to the large-diameter portion 18 is projected and exposed to the outside. .

The casing 23 has a connector connecting portion 23b extending in a direction perpendicular to the axial direction of the coil bobbin 11. The connecting portion 23b has a concave shape with an open tip, and a pair of the output terminals 22 are provided on the inner surface thereof.
The other end 22b of the is projected. A connector (not shown) electrically connected to the output terminal 22 is inserted and connected inside the connector connecting portion 23b.

The rotation angle sensor having the above structure is manufactured as follows. First, a coil is wound around the coil winding portion 14 so as to be sandwiched between both flanges of the coil bobbin 11, and the detection coil 15 is attached to the coil bobbin 11.

Next, the elastic sealing material 19 is placed on the bottom surface of the magnet housing portion 13, that is, on the boundary wall portion 12, and the core iron core 16 is inserted from the magnet housing portion 13 side so that the small-diameter shaft portion 17 is elastic. The seal material 19 is inserted through the center hole 19b and the coil winding portion 14 is penetrated through the center hole 14b. Alternatively, after the elastic seal material 19 is fitted to the small-diameter shaft portion 17 of the core iron core 16, the iron core 16 is inserted from the magnet accommodating portion 13 side, and the small-diameter shaft portion 17 penetrates the center hole 14b of the coil winding portion 14. Let Thereby, the elastic seal material 1
9 is sandwiched between the boundary wall portion 12 and the large diameter portion 18 of the core iron core 16.

Thereafter, the permanent magnet 20 is placed in the magnet housing portion 13.
And then the magnetism collector 2 so as to overlap the magnet 20.
1 is housed in the magnet housing portion 13. Also, the magnet housing 1
A pair of output terminals 22 are provided outside the wiring 3, and the coil terminals of the detection coil 15 are connected to each other by soldering or the like.

Finally, the assembly for embedding, which is assembled as described above, is set in advance in a mold for injection-molding the casing 23, and then a synthetic resin material is injected and filled in the mold. The casing 23 is injection molded. As a result, the manufacture of the electromagnetic rotation angle sensor having the configuration shown in FIG. 1 is completed.

Then, with such manufacturing, the magnetism collector 21 is formed.
Since a high molding pressure acts on the large diameter portion 18, the large diameter portion 18 presses the large diameter portion 18 toward the boundary wall portion 12 side. As a result, the elastic sealing material 19 is elastically deformed in a compressed state, and each surface thereof is provided in elastic contact with all the surfaces facing the surroundings.

By the way, in the rotation angle sensor having the above-mentioned structure, each part repeats expansion and contraction due to the change of the ambient temperature and the heat generation of the detection coil 15 and its stop, but the coil bobbin 11 and the casing 23 made of the synthetic resin, the ferrous metal, and the like. The thermal expansion of the manufactured core iron core 16 and the like differs depending on the materials of each other. Therefore, based on the difference, the small-diameter shaft portion 17 of the core iron core 16, the center hole 14b of the coil bobbin 11, and the flange cover portion 23b of the casing 23 are formed. A gap may be formed between the small-diameter shaft portion 17 and the portion that penetrates. When a gap (not shown) is generated in this way, water penetrates into the sensor through the gap as the rotation angle sensor is exposed to water.

However, in this rotation angle sensor, the boundary wall portion 12 that forms the boundary between the coil winding portion 14 having the center hole 14b and the magnet accommodating portion 13 and the magnet accommodating portion 13 of the core iron core 15 are provided. An annular elastic sealing material 19 is sandwiched between the large-diameter portion 18 and the large-diameter portion 18.

For this reason, the intruding water can be blocked by the elastic sealing material 19, and the intruding water from the boundary wall portion 12, that is, the opening end side of the magnet accommodating portion 13 can be prevented.

The elastic seal material 19 forming the waterproof seal is sandwiched in a compressed state, and if the sandwiching force is reduced, it can be elastically deformed so as to expand accordingly. Therefore, even if the distance between the boundary wall portion 12 that sandwiches the elastic sealing material 19 and the large diameter portion 18 of the core iron core 16 changes due to the difference in thermal expansion, due to the elastic deformation that follows it,
Since it is possible to maintain elastic close contact with all the surfaces facing the surroundings, the waterproof sealing performance can be maintained.

Therefore, even if water enters the inside of the sensor, it will pass through the magnet accommodating portion 13 and the output terminal 2
It never reaches the 2nd side. In this way, it is possible to prevent water from entering the output terminal 22 portion with high reliability, thereby eliminating the short circuit of the output terminal 22 and preventing the output of an erroneous signal.

In addition, as described above, the inside of the magnet accommodating portion 13 is prevented by reliably blocking the infiltrated water in the boundary wall portion 12 which is the front stage of the magnet accommodating portion 13 when viewed from the water infiltration path. The permanent magnet 20 and the magnetism collector 21 which are the iron-based metal parts housed in are not exposed to the invading water. Therefore, these metal parts do not rust, and it is possible to prevent the product life from being shortened due to rust.

Further, in the structure of the waterproof seal,
Since a reliable waterproof seal can be made without providing a seal projection integral with the casing 23 at the opening end of the magnet housing portion 13,
Since it is not necessary to provide an annular step on the circumference of the magnetism collector 21 to form the seal projection, the shape and machining of the magnetism collector 21 can be simplified, and thus the magnetism collector 21 can be obtained at a low cost. You can

Incidentally, the actual Kaihei 6-given as a conventional example.
According to Japanese Patent No. 2232, it is necessary to form an annular step portion for forming the sealing projection at the end portion of the magnetism collector opposite to the permanent magnet, which makes the magnetism collector difficult to process. However, such a problem can be solved in this embodiment. However, since the provision of the seal protrusion is effective to some extent, in order to prevent the water from entering the output terminal 22 side more reliably, it is not necessary to form the seal protrusion integrally with the casing 23. Do not disturb

Further, as described above, in the structure in which the elastic sealing material 19 is sandwiched between the boundary wall portion 12 and the large-diameter portion 18 of the core iron core 16 to make a waterproof seal, the permanent magnet 20 and the magnetism collector 21 are provided. The desired waterproof sealing effect can be stably obtained without being restricted by the shape. Moreover, when the diameter of the large diameter portion 18 of the elastic sealing material 19 and the core iron core 16 is set to be substantially the same as the diameter of the boundary wall portion 12, a wider sealing area is secured, and accordingly, the waterproof sealing effect is obtained. Can be increased.

[0037]

As described above in detail, according to the electromagnetic rotation angle sensor of the present invention, the ring-shaped elastic seal member for blocking the water invading the inside of the sensor is provided in the coil winding portion of the coil bobbin and the magnet housing. It is sandwiched between the boundary wall between the core and the core and the large-diameter part arranged in the magnet accommodating part of the core iron core, and this sealing material prevents water from entering the boundary wall first. Therefore, it is possible to prevent the permanent magnet and the magnetism collector which are the iron-based metal parts housed inside the magnet housing part from being exposed to the invading water and rusting. Even if the distance between the boundary wall and the large-diameter portion changes due to the difference in thermal expansion, the elastic sealing material elastically deforms to maintain the waterproof sealing performance, so that water cannot enter the output terminal. It can be prevented with high reliability.

[Brief description of drawings]

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

FIG. 2 is an exploded perspective view showing a configuration of a main part of the embodiment.

FIG. 3 is a vertical cross-sectional view showing a configuration of an electromagnetic rotation angle sensor according to a conventional example.

[Explanation of symbols]

 11 ... Coil bobbin, 12 ... Boundary wall part, 13 ... Magnet accommodation part, 14 ... Coil winding part, 14b ... Central hole of coil winding part, 15 ... Detection coil, 16 ... Core iron core, 17 ... Small diameter axis of core iron core Part, 18 ... Large diameter part of core iron core, 19 ... Elastic seal material, 20 ... Permanent magnet, 21 ... Magnet collector, 22 ... Output terminal, 23 ... Casing.

Claims (1)

[Claims] 1. A magnet accommodating portion on one end side and a coil winding portion on the other end side, and the magnet accommodating portion and the coil winding portion form a bottom of the magnet accommodating portion and the coil winding portion. A coil bobbin that is integrally continuous through a boundary wall that also serves as a flange on the side of the magnet containing portion, a detection coil that is wound around the coil winding portion, and is attached to a large diameter portion at one end of the small diameter shaft portion. And a core iron core provided by arranging the large-diameter portion in the magnet accommodating portion and penetrating the small-diameter shaft portion in the center hole of the coil winding portion, and in contact with the large-diameter portion. A permanent magnet housed in the magnet housing part; a magnetism collector housed in the magnet housing part in contact with the permanent magnet from the side opposite to the large diameter part; Part connected to the detection coil Of the output terminals and a casing made of synthetic resin in which the other end of these output terminals and the other end of the small-diameter shaft portion are exposed and the other parts are embedded and provided. The rotation angle sensor is an electromagnetic rotation angle sensor characterized in that an elastic elastic ring-shaped seal material is interposed between the boundary wall portion and the large diameter portion of the core iron core.