JPH08220117A - Sealing structure for member - Google Patents

Abstract

PURPOSE: To obtain a sealing structure for a member being employed suitably when appropriate sealing properties are required around a member exposed to the outside of housing in which the number of components is decreased while enhancing the productivity. CONSTITUTION: A bobbin 14 is applied with a winding 16 to form an electromagnetic coil 12. A yoke 28 provided, at one end thereof, with an electromagnetic pickup part 28a is inserted into the hollow part of the electromagnetic coil 12. A sealing part 22a is provided around the electromagnetic pickup part 28a of the yoke 14 and a cover body 22 made of thermoplastic elastomer is disposed while surrounding the electromagnetic coil 12. A housing 30 is then injection molded to expose the electromagnetic pickup part 28a to the outside at a temperature exceeding the melting point of the cover body 22 temporarily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a member sealing structure, and more particularly, it is necessary to secure an appropriate sealing property around a member exposed to the outside of a housing, such as an electromagnetic pickup portion in an electromagnetic pickup sensor. In some cases, the present invention relates to a seal structure for a member.

[0002]

2. Description of the Related Art Conventionally, an electromagnetic pickup sensor has been known as a sensor constituting a vehicle wheel speed sensor or the like. This electromagnetic pickup sensor has a structure in which a yoke having one end as an electromagnetic pickup portion is arranged in the center of an electromagnetic coil, and is a sensor that detects a change in magnetic resistance occurring near the electromagnetic pickup portion as an electric signal.

Here, the above-mentioned wheel speed sensor is composed of a magnetic rotor having irregularities on its outer periphery and an electromagnetic pickup sensor arranged near the rotor. That is, the rotor has irregularities on its outer circumference and is made of a magnetic material. In this case, when the wheel rotates, the magnetic resistance in the vicinity of the electromagnetic pickup section changes periodically, and the electromagnetic pickup sensor outputs a pulse signal at a cycle corresponding to the vehicle speed.

By the way, the electromagnetic pickup sensor as described above is a sensor for detecting a change in magnetic resistance which occurs near the electromagnetic pickup portion formed at one end of the yoke.
Therefore, even when the structure in which the electromagnetic coil or the like is housed is adopted, only the electromagnetic pickup portion of the yoke needs to be exposed to the outside.

On the other hand, when the electromagnetic pickup sensor is used as the above-described wheel speed sensor or the like, it may be difficult to isolate the periphery of the electromagnetic pickup portion from the outside air due to various restrictions. Therefore, for the electromagnetic pickup sensor used in such a situation, appropriate waterproofness is required around the electromagnetic pickup portion.

On the other hand, for example, Japanese Patent Laid-Open No. 2-1266
Japanese Unexamined Patent Publication (Kokai) No. 1 discloses an electromagnetic pickup sensor in which a yoke and an electromagnetic coil are housed in a housing having a through hole that allows the front end of the yoke to pass therethrough, and an O-ring ensures a sealing property around the through hole. .

That is, in this electromagnetic pickup sensor, an O-ring is interposed between the housing and the tip of the yoke, and each component is assembled so that the O-ring is elastically deformed to some extent, thereby realizing a necessary seal structure. Is what you are trying to do. In this case, if an appropriate elastic deformation can be imparted to the O-ring, an appropriate sealing property can be ensured between the housing and the yoke, and moisture can be prevented from entering the periphery of the electromagnetic coil.

[0008]

However, the above-mentioned conventional electromagnetic pickup sensor has a structure in which the housing is formed in advance separately from the electromagnetic coil and the like, and the O-ring and the electromagnetic coil are sequentially assembled therein. Therefore, assembling workability is not necessarily good as compared with a configuration in which the housing is molded outside the electromagnetic coil or the like by injection molding or the like.

On the other hand, the technique of molding the housing by injection molding, potting, etc. has been widely known, but it is difficult to impart an appropriate elastic deformation to the O-ring during the molding process. is there. Also,
Since the O-ring is generally weak against heat, when molding is performed with the O-ring arranged, the O-ring may be deteriorated by the heat during molding. Therefore, the housing of the internal member including the exposed portion such as the electromagnetic pickup portion,
When forming by molding, it is difficult to secure the sealing property around the exposed portion with the O-ring.

Further, when a housing is formed on the outer circumference of the electromagnetic coil by molding, it is known that a winding or the like is further wound around the outer circumference of the winding of the electromagnetic coil to protect the winding. If necessary,
This is accompanied by adverse effects such as an additional assembling process and an increase in the number of parts.

When an internal member such as an electromagnetic coil is molded by injection molding, it is necessary to properly hold the internal member in a molding die during molding. For this reason, it is impossible to completely cover the inner member by molding once, and the portion of the inner member held in the molding die remains exposed from the housing even after molding. Become. Therefore, if the housing is formed by simply molding the outer circumference of the electromagnetic coil, it is not possible to obtain an appropriate sealing property at the exposed holding portion, and if the inner member as a whole is required to be waterproof, it is desirable. There is also a problem that it is impossible to secure the waterproof property of the.

As described above, the sealing structure of the member used in the conventional electromagnetic pickup sensor causes various problems when the housing of the internal member is molded, and is not suitable as the sealing structure in such a case. It was a thing. The present invention has been made in view of the above-mentioned points, and the periphery of the exposed portion exposed to the outside of the housing is covered with a thermoplastic elastomer or a cover body made of an adhesive thermoplastic resin, It is an object of the present invention to provide a member seal structure that solves the above problems by welding the cover body and its peripheral members.

[0013]

The above-mentioned object is defined in claim 1.
As described in paragraph 1, an internal member having an exposed portion exposed to the outside, a cover body made of a thermoplastic elastomer and having a seal portion surrounding the exposed portion, and a mold at a temperature temporarily exceeding the melting point of the cover body. This is achieved by a sealing structure of a member that is formed and that includes a housing that covers the internal member with the exposed portion exposed to the outside.

The above object is as described in claim 2.
A cover body including an internal member having an exposed portion exposed to the outside, a thermoplastic resin having an adhesive, and a seal portion surrounding the exposed portion, and molding at a temperature temporarily exceeding the melting point of the cover body. And a housing that covers the internal member with the exposed portion exposed to the outside,
It is also achieved by the seal structure of the member including.

Further, as described in claim 3, the above object is, in the seal structure of a member according to claim 1 or 2, the inner member, which is formed by winding a conducting wire around a bobbin. And a magnetic body having an electromagnetic pickup unit at one end, the yoke being inserted into the hollow portion of the electromagnetic coil, the sensor body, wherein the exposed portion is an electromagnetic pickup unit of the yoke. It is also achieved by the sealing structure of a certain member.

Further, the above object is, as described in claim 4, in the seal structure for a member according to claim 3,
The cover body is also achieved by a seal structure of a member formed so as to cover the outer circumference of the electromagnetic coil.

The above object is, as described in claim 5, the seal structure of the member according to claim 1 or 2, wherein the inner member is a hollow portion formed by winding a conductive wire around a bobbin. And a magnetic member having an electromagnetic pickup portion at one end, the yoke being inserted into a hollow portion of the electromagnetic coil, and a sensor main body, wherein the exposed portion is connected to the sensor main body. A seal structure for a member, which is a wire harness.

[0018]

In the invention of claim 1, the exposed portion is surrounded by the seal portion of the cover body made of thermoplastic elastomer. Therefore, an appropriate sealing property is ensured between the exposed body and the cover body due to the elasticity of the thermoplastic elastomer. Further, the inner member is covered by the housing together with the cover body. At this time, the housing
Since the cover body and the housing are molded at a temperature temporarily exceeding the melting point of the cover body, the cover body and the housing are welded to each other during the molding process, and an appropriate sealing property is secured between them. Therefore, an appropriate sealing property is secured between the cover body and the exposed portion and between the cover body and the housing.

In the second aspect of the invention, the periphery of the exposed portion is surrounded by the seal portion of the cover body made of an adhesive thermoplastic resin. In this case, an appropriate sealing property is ensured between the exposed body and the cover body due to the cover body being adhered to the exposed body. Also, the internal member is
It is covered by the housing together with the cover body. At this time, since the housing is molded at a temperature that temporarily exceeds the melting point of the cover body, the cover body and the housing are welded to each other during the molding process, and an appropriate sealing property is secured between them. Therefore, an appropriate sealing property can be secured between the cover body and the exposed portion and between the cover body and the housing.

According to the third aspect of the present invention, the electromagnetic coil emits an electromotive force according to the amount of change in the magnetic flux when the magnetic flux passing through the yoke inserted in the hollow portion changes. Further, the yoke has an electromagnetic pickup section at one end thereof. Therefore, when the magnetic field in the vicinity of the electromagnetic pickup changes, the electromagnetic coil outputs an electric signal corresponding to the change. By the way, in the present invention, the electromagnetic coil and the yoke constitute an internal member with which the housing is covered. The electromagnetic pickup portion of the yoke constitutes an exposed portion exposed from the housing. In this case, the electromagnetic pickup portion is exposed to the outside of the housing while ensuring a proper sealing property around the electromagnetic pickup portion.

In the invention of claim 4, the cover body surrounds the electromagnetic pickup portion of the yoke and covers the outer circumference of the electromagnetic coil. In this case, the portion of the cover body that covers the outer periphery of the electromagnetic coil functions as a film that protects the winding of the electromagnetic coil when the housing is molded. Furthermore, when molding the housing, it is necessary to hold the electromagnetic coil in the molding die, so a part of the cover body that covers the electromagnetic coil is exposed to the outside of the molded housing. The cover body and the housing are also welded at this portion. Therefore, properly protect the winding of the electromagnetic coil,
In addition, it is possible to mold the housing by molding while ensuring an appropriate sealing property around the sensor body.

According to the fifth aspect of the invention, the electromagnetic coil emits an electromotive force according to the amount of change in the magnetic flux when the magnetic flux passing through the yoke inserted in the hollow portion changes. This electromotive force is output as an electric signal through a wire harness, one end of which is connected to the electromagnetic coil inside the sensor body and the other end of which is led out from the sensor body. On the other hand, in the present invention, the sensor body constitutes the internal member and the wire harness constitutes the exposed portion. Therefore, an appropriate sealing property is secured around the portion where the wire harness is exposed from the sensor body.

[0023]

1 is a front sectional view showing the structure of an electromagnetic pickup sensor 10 which adopts a member seal structure according to an embodiment of the present invention. In the figure, the electromagnetic coil 12
Is formed by forming a winding 16 on the outer circumference of the bobbin 14.

The bobbin 14 is formed by injection molding a thermoplastic resin into a shape having a hollow portion as shown in FIG. A magnet 18 is attached to the inside of the bobbin 14, and two terminals 20 are fixed to the upper portion thereof (only one is shown in FIG. 1). The winding wire 16 is formed by a conductive wire wound around the bobbin 14 a predetermined number of times, and both ends thereof are resistance-welded to the two terminals 20, respectively.

The electromagnetic coil 12 is covered by the cover body 22 except for the fixing portion of the terminal 20 and a part of the hollow portion of the bobbin 14. The cover body 22 is formed by injection molding a thermoplastic elastomer around the electromagnetic coil 12. In the following description, the cover body 22
The process of molding is called primary molding.

FIG. 2 is an enlarged view of the vicinity of the lower end of the electromagnetic coil 12 covered by the cover body 22. As shown in the figure, the cover body 22 is formed so as to surround the hollow portion of the bobbin 14. A seal portion 22a having a semicircular cross section is annularly provided at the wraparound portion.

By the way, in this embodiment, when the cover body 22 is injection-molded, a grommet 24 made of the same thermoplastic elastomer as that of the cover body 22 is formed by a so-called parent-child removing method, and the grommet 24 is formed as shown in FIG. The wire harness 26 is fitted on the outer periphery of the wire harness 26 as shown in FIG.

The grommet 24 is a member that is used to finally secure the sealing property around the wire harness 26, and as shown in FIG. 3, a plurality of seal portions 24a having a semicircular cross section on the inner periphery thereof. , 24b in a ring shape. The number of the seal portions 24a and 24b is not limited to two and may be set to a larger number.

The wire harness 26 inserted into the grommet 24 has two signal wires 26 inside, as shown in FIG.
a, 26b. These signal lines 26a, 26
b is resistance-welded to each of the two terminals 20, while the insertion position of the grommet 24 is adjusted so as to have a regular positional relationship with the electromagnetic coil 12 under such circumstances.

Further, in the hollow portion of the electromagnetic coil 12, FIG.
A cylindrical yoke 28 is press-fitted from the lower end side thereof so that the upper end thereof abuts the magnet 18. The yoke 28 is a magnetic member having an electromagnetic pickup portion 28a at its lower end, and has a diameter substantially the same as the hollow portion of the bobbin 14 and a diameter slightly larger than the inner diameter of the seal portion 22a of the cover body 22. Therefore, as shown in FIG. 1, in the state where the yoke 28 is press-fitted into the hollow portion of the electromagnetic coil 12, the seal portion 22a is appropriately elastically deformed, and a proper sealing property is secured between the cover body 22 and the yoke 28. It will be in the state of being.

In this embodiment, Toray Hytrel 25, which is a polyester resin as the thermoplastic elastomer, is used.
The cover body 22 and the grommet 24 are injection-molded at a molding temperature of 235 ° C. using a mixed material of 51 (trade name) and Toray Hytrel 4057 (trade name) (both have melting points of 163 ° C.).

With this structure, it is possible to impart appropriate elasticity to the cover body 22 and the seal portions 22a, 24a, 24b of the grommet 24, and in the electromagnetic pickup sensor 10, the wire harness 26 and the grommet 24 are provided.
It is possible to appropriately secure both the waterproofness required between the magnet and the magnet and the waterproofness required between the yoke 28 and the electromagnetic coil 12.

The outer periphery of the electromagnetic coil 12 covered with the cover body 22, the wire harness 26 and the grommet 24 fixed to the terminal 20, is covered with a housing 30 formed by injection molding. still,
In the following description, the molding process of the housing 30 will be described below.
This is called next molding.

That is, the cover body 22 and the grommet 2
When the primary molding by the thermoplastic elastomer for forming 4 is completed and then the fixing process of the wire harness 26 described above is completed, both the electromagnetic coil 12 and the grommet 24 are set in the mold for secondary molding. To be done. And
In this example, Toray PBT, which is a polyester-based thermoplastic resin similar to the above-mentioned thermoplastic elastomer, is used.
Secondary molding is performed at a molding temperature of 255 ° C. using 5101G-30 (trade name) (melting point 224 ° C.).

In this case, since the secondary molding temperature exceeds the melting point (163 ° C.) of the thermoplastic elastomer to be primary molded, the surfaces of the cover body 22 and the grommet 24 are melted during the secondary formation process. . Then, the primary molding resin and 2
Coupled with the fact that the resin for the next molding is the same type of polyester, the inner surface of the housing 30 and the surfaces of the cover body 22 and the grommet 24 are firmly welded during the molding process of the housing 30, and stable between the two. A bond is formed.

Further, the electromagnetic pickup sensor 10 is provided with a stay 32 used for fixing the electromagnetic pickup sensor 10 at a predetermined position outside the housing 30. A metal collar 34 is fitted into the stay 32 for reinforcement against bolting. That is, the assembly of the electromagnetic pickup sensor 10 requires the metal collar 34.
It is done by inserting a bolt inside the and tightening the bolt with the bolt.

By the way, the electromagnetic pickup sensor 10
Is a sensor that detects changes in the magnetic field in the vicinity of the electromagnetic pickup unit 28a. That is, in the electromagnetic pickup sensor 28, for example, the electromagnetic pickup portion 28a is made to face a rotor in which an uneven magnetic material is arranged on the entire outer circumference or a rotor in which only a part of the outer circumference is formed of a magnetic material. It is used as it is.

In such a situation, when the rotor rotates, the magnetic material provided in the rotor passes near the electromagnetic pickup portion 28a as the rotor rotates. Then, when the magnetic body passes in this way, the magnetic state in the vicinity of the electromagnetic pickup unit 28a temporarily changes, and the magnet 1
Due to the magnetomotive force of No. 8, the amount of magnetic flux penetrating the inside of the yoke 28 varies.

In this case, an induced electromotive force is generated in the electromagnetic coil 12 according to a change in magnetic flux, and as a result, a pulse-shaped signal corresponding to the rotation of the rotor is generated on the signal lines 26a and 26b of the electromagnetic pickup sensor 10. Is supplied. At this time, the electromagnetic pickup unit 28a needs to be exposed to the outside of the housing 30 in order to detect the change in the state of the magnetic field in the vicinity thereof. On the other hand, for example, when the electromagnetic pickup sensor 10 is used as a vehicle wheel speed sensor or the like, since the electromagnetic pickup sensor 10 is exposed to the outside air, the electromagnetic pickup sensor 28a or the like is suitable around the portion exposed from the housing 30. As described above, a high sealing property is required.

On the other hand, the electromagnetic pickup sensor 10 of this embodiment has the electromagnetic pickup section 28 as described above.
In the vicinity of a, between the cover body 22 and the yoke 28,
Also, it has an appropriate sealing property at the interface between the cover body 22 and the housing 30. Further, in the periphery of the grommet 24, a proper sealing property is provided between the inner periphery of the grommet 24 and the outer skin of the wire harness 26 and the interface between the grommet 24 and the housing 30. In this case, there is no part around the electromagnetic pickup sensor 10 where the moisture in the outside air is allowed to enter.
When 0 is used as a vehicle wheel speed sensor or the like, the sealing property required is sufficiently satisfied.

If the housing 30 is molded in advance and then the electromagnetic coil 12 and the grommet 24 are assembled through a sealing material such as an O-ring, a desired sealing property can be secured, but this embodiment does not. The number of parts to be assembled is larger than that of the above configuration, and thus the number of assembling steps is large. In this sense, the electromagnetic pickup sensor 10 of the present embodiment has an advantage that desired waterproofness can be ensured with good productivity by a small number of parts.

By the way, when performing molding such as injection molding on the outer periphery of the electromagnetic coil 12, the electromagnetic coil 12
It is necessary to consider the prevention of disconnection of the winding 16.
Therefore, when there is no member corresponding to the cover body 22 in the electromagnetic pickup sensor 10, it is necessary to wind a tape or the like around the winding wire 16 to form a protective film before molding the housing 30. is there.

On the other hand, as in this embodiment, the winding 16
In the structure in which the outer periphery of is covered with the cover body 22 in advance, combined with the cover body 22 having an appropriate elasticity, the injection at the time of the secondary molding without adding any special protective film. The winding 16 can be appropriately protected from pressure or the like. In this sense, the electromagnetic pickup sensor 10 of the present embodiment has an advantage that it is possible to prevent an increase in the number of parts and the number of working steps due to the addition of the protective member.

The coefficient of thermal expansion of the winding 16 and the coefficient of thermal expansion of the housing 30 are not the same. For this reason, if the environmental temperature of the electromagnetic pickup sensor 10 changes, stress due to the difference in thermal expansion from the housing 30 is applied to the winding 16. Therefore, the electromagnetic pickup sensor 10
As the change with time, it is also assumed that the winding 16 is broken due to the repeated application of the stress. However, in this embodiment, since the outer circumference of the winding wire 16 is covered with the cover body 22, the stress received by the winding wire 16 is relaxed. Therefore, the electromagnetic pickup sensor 1
According to 0, it is possible to obtain an advantage that the disconnection of the winding wire 16 due to the difference in thermal expansion from the housing 30 can be prevented.

By the way, in order to realize the structure shown in FIG. 1 by secondarily molding the housing 30 on the outer circumference of the electromagnetic coil 12, when performing the secondary molding, the electromagnetic coil is formed in the molding die for the secondary molding. It is necessary to properly hold 12 and the like. Therefore, in this embodiment, as shown in FIGS. 4 (A) and 4 (B), the projections 22b-2 at the eight locations are formed on the outer periphery of the cover body 22.
2i is provided, and the electromagnetic coils 12 and the like are set inside the mold using the protrusions 22b to 22i as holding portions.

In this case, the protrusions 22b to 22i have the same shape as in FIG.
If the protrusions 22b to 22i and the housing 30 are not welded to each other as shown in Fig. 10, the appropriate sealing performance cannot be ensured at those portions, and the electromagnetic pickup sensor 10 A situation occurs in which water cannot be blocked inside.

On the other hand, in the electromagnetic pickup sensor 10 of the present embodiment, as described above, the seal that welds the cover body 22 to the housing 30 over the entire outer circumference thereof, that is, over the entire area including the periphery of the projections 22b to 22i. The structure is adopted. Therefore, in the electromagnetic pickup sensor 10, although the protrusions 22b to 22i are exposed from the housing 30, a good sealing property is secured around them. In this sense, the seal structure adopted by the electromagnetic pickup sensor 10 is 2
The structure is such that the housing 30 can be molded and the desired sealability can be ensured, including the retention of the electromagnetic coil 12 and the like in the mold during the next molding.

In this embodiment, from the viewpoint of simplifying the shape of the secondary molding die, the protrusion 2 is provided on the cover body 22 side.
Although 2b to 22i are provided, the same effect can be obtained even if the cover body 22 is formed in a simple cylindrical shape and the protrusion for holding the cover body 22 is provided on the secondary molding die side.

Further, in the above embodiment, the housing 3
Although 0 is used for injection molding, the method of molding is not limited to this, and similar effects can be obtained by, for example, potting.
Further, the above-mentioned example is based on a thermoplastic elastomer for primary molding,
Polyester resin is used as the thermoplastic resin for secondary molding, and other materials such as nylon resin, urethane resin, styrene resin, olefin resin, amide resin, ionomer, vulcanized rubber, Materials such as plastic can be applied. In addition, the primary molding resin and 2
The next molding resin does not necessarily have to be the same type of resin,
It is also possible to use a different type of resin as long as proper welding occurs between the two.

By the way, the electromagnetic pickup sensor 10 described above, including the periphery of the electromagnetic pickup section 28a,
This configuration is effective when a good sealing property is required on the entire outer circumference of the electromagnetic pickup sensor 10. On the other hand, for example, when waterproofness is required only around the electromagnetic pickup portion 28a, it is not necessary to dare to cover the entire outer peripheral side of the electromagnetic coil 12 with the thermoplastic elastomer.

That is, in this case, as shown in FIG. 5, it is possible to form the cover body 40 made of thermoplastic elastomer only on the portion around the inner circumference of the bobbin 14. That is, in this case, the seal portion 40a of the cover body 40 ensures the sealing property between the yoke 28 and the cover body 40, and the cover body 40 and the housing 30 are welded to each other. It is the same as the electromagnetic pickup sensor 10 shown in FIG. 1 in that the sealing property with the housing 30 is secured.

Therefore, even when the structure shown in FIG. 5 is used, the waterproof property around the electromagnetic pickup portion 28a is properly ensured, and as described above, the waterproof property is required only around the electromagnetic pick-up part 28a. Under the conditions, the required function can be sufficiently satisfied. In this sense
The electromagnetic pickup sensor using the cover body 40 as shown in FIG. 5 also has an effect of easily and surely achieving a desired sealing property.

FIG. 6 is a front sectional view showing the structure of an electromagnetic pickup sensor 50 which employs a member sealing structure according to another embodiment of the present invention. In the figure, the same parts as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be simplified or omitted.

Electromagnetic pickup sensor 50 of this embodiment
Is characterized in that before the housing 30 is molded, the wire harness 26 is surrounded by the hot melt 52 made of an adhesive thermoplastic resin to ensure the sealing property around the wire harness 26. There is.

Here, the thermoplastic resin constituting the hot melt 52 is a polyamide resin having a softening point at 140 to 170 ° C., specifically, Macromelt (trade name) 6238, 6239, 6240, 6827, 679
0 (maker: Henkel) is used. As a method for molding the hot melt 52, hot pressing, injection molding or the like can be applied, but in this embodiment, injection molding is used.

Hereinafter, the manufacturing process of the electromagnetic pickup sensor 50 will be described in detail with reference to FIG. FIG. 7 (A)
FIG. 6 is a perspective view showing a state in which hot melt 52 is primarily molded so as to surround wire harness 26. here,
In this embodiment, 1 of the hot melt 52 is formed at a molding temperature of 200 to 220 ° C. for a softening point of 140 to 170 ° C.
Next molding is performed.

By the way, the outer skin of the wire harness 26 is made of polyurethane 26. Polyester is used for the insulating material of the two signal lines 26a and 26b. In this case, when the hot melt 52 is molded at the molding temperature as described above, as shown in FIG. 7B, the boundary between the outer cover of the wire harness 26 and the hot melt 52, and the insulating material and the hot melt of the signal lines 26a and 26b. An adhesive interface is formed at the boundary with 26.

FIG. 7C is a sectional view showing an essential part of the state after the hot-melt 52 is primarily molded and the housing 30 is secondarily molded as described above. As the material of the housing 30, polybutylene terephthalate (PBT), polyamide (PA), or the like can be applied, but in the present embodiment, PBT is used as the material.
Secondary molding is performed at a molding temperature of 0 to 260 ° C.

In this case, since the hot melt 52 is plasticized again in the process of molding the housing 30, as shown in FIG.
As shown in (C), a welding layer 56 is formed at the boundary between the housing 30 and the hot melt 52. Therefore, also in the electromagnetic pickup sensor 50 shown in FIG. 6, as in the electromagnetic pickup sensor 10 shown in FIG. 1, excellent sealing performance is secured in the exposed portion of the wire harness 26.

The electromagnetic pickup sensor 5 shown in FIG.
At 0, the molding pressure when molding the housing 30 strengthens the close contact between the hot melt 52 and the wire harness 26 (including the signal wires 26a and 26b). Therefore, a high sealability is ensured between the hot melt 52 and the wire harness 26, which exceeds the sealability due to the adhesive ability of the thermoplastic resin forming the hot melt 52.

By the way, when the electromagnetic pickup sensor 50 is used as a vehicle wheel speed sensor or the like, the wire harness 26 take-out portion may be bent.
Further, it is assumed that the wire harness 26 is iced and the load is applied to the take-out portion of the wire harness 26 as stress. Therefore, the electromagnetic pickup sensor 50
In the case where is used as a wheel speed sensor or the like, it is necessary to give sufficient strength to the vicinity of the takeout portion of the wire harness 26.

On the other hand, in the electromagnetic pickup sensor 50 of the present embodiment, the take-out portion of the wire harness 26 is molded in the engineering plastic such as PBT that constitutes the housing 30, and sufficient around the take-out portion. Has strength. Furthermore, according to this structure, the hot melt 52 is not directly exposed to water, and high chemical resistance can be secured. In this sense, the seal structure adopted by the electromagnetic pickup sensor 50 has an advantage that it is effective in improving durability and reliability around the wire harness.

Further, in this embodiment, the hot melt 52
The polyamide resin used as the material for the
It has a higher water absorption than the PBT constituting the above. Therefore, the hot melt 52 has a property of easily swelling as compared with the housing 30. On the other hand, hot melt 52
Since it is housed inside the housing 30 as shown in FIG. 6, the volume cannot be increased toward the outside. Therefore, in the electromagnetic pickup sensor 50, as the hot melt 52 swells, the adhesion strength between the hot melt 52 and the wire harness 26 and between the hot melt 52 and the housing 30 increases, and the wire harness 26 take-out portion. A high sealing property can be obtained in the periphery.

By the way, the sealing structure shown in FIGS. 6 and 7 is a structure in which the hot melt 52 also covers the outer skin of the wire harness 26, but the structure is not limited to this, and as shown in FIG. The same function can be realized by using the hot melt 58 that covers only the signal lines 26a and 26b.

That is, in FIGS. 8A and 8B, the hot melt 5 covering only the signal lines 26a and 26b, respectively.
8 in close contact with the outer skin of the wire harness 1
The perspective view and sectional drawing at the time of the following shaping | molding are shown. In this case, as shown in FIG. 2B, the outer skin of the wire harness 26, the boundary between the hot melt 58, and the signal lines 26a and 26b.
Adhesive interfaces 60a and 60b are formed at the boundaries between the insulating material and the hot melt 58, respectively. And the same figure (C)
As shown in FIG. 7, when the housing 30 is subjected to the secondary molding, a welding layer 62 is formed between the hot melt 58 and the housing 30, and a structure substantially similar to the sealing structure shown in FIGS. 6 and 7 is realized. Will be done. In this case, the hot melt 58 can be downsized, which is effective in reducing the consumption of the polyamide resin.

By the way, the seal structures shown in FIGS. 6 to 8 utilize the fact that a thermoplastic resin such as a polyamide resin exhibits excellent adhesiveness to polyurethane or the like, and therefore the seal structure around the take-out portion of the wire harness 26 is used. Although it is intended to secure the sealing property, a thermoplastic resin such as a polyamide resin exhibits good adhesiveness not only to polyurethane and the like but also to metal.

Therefore, the electromagnetic coil 12 in FIG.
If the cover body 22 covering the cover is molded with a thermoplastic resin such as polyamide, the seal portion 2 of the molded cover body 22 is formed.
2a is bonded to the yoke 28. Then, after that, when the housing 30 is secondarily molded, the boundary between the cover body 22 and the housing 30 is welded, so that an appropriate sealing property is eventually secured around the electromagnetic pickup portion 28a. In this case, the cover body 2
Also in the vicinity of the protrusions 22b to 22i (see FIG. 4) of No. 2, as in the case of using the thermoplastic elastomer,
Appropriate sealing property will be secured.

By the way, also in the electromagnetic pickup sensor 50, as in the case of the electromagnetic pickup sensor 10 described above, the entire outer peripheral side of the electromagnetic coil 12 is intentionally adhered even when the entire outer periphery thereof is not required to be sealed. It need not be coated with some thermoplastic.

In such a case, FIG. 9 shows a state in which a cover body 28a made of an adhesive thermoplastic resin is molded only around the electromagnetic pickup portion 28a (FIG. 9A), and the cover. It shows a state where the housing 30 is secondarily molded by covering the body 28a ((B) of the same figure). In this case, it is possible to reduce the amount of consumption of the thermoplastic resin as compared with the structure in which the entire circumference of the electromagnetic coil 12 is covered with the cover body 22, which is advantageous for cost reduction.

By the way, in constructing the electromagnetic pickup sensor, the conductive material for extracting the electric signal from the electromagnetic coil 12 is not necessarily limited to the wire harness. That is, in the so-called connector type electromagnetic pickup sensor 70 as shown in FIG.
The terminal 72 is erected on the electromagnetic coil 12 and the connector 74
In some cases, a structure that realizes a conductive path up to is adopted.

When such an electromagnetic pickup sensor 70 is used as a wheel speed sensor, water drops and the like may remain inside the connector 75. Therefore, even in such a connector type electromagnetic pickup sensor 70, it is necessary to secure an appropriate sealing property around the takeout portion of the terminal 72. That is, the electromagnetic pickup sensors 10 and 50 using the wire harness 26 (see FIG. (See FIG. 6).

On the other hand, in this embodiment, as shown in FIG.
As shown in 0, the vicinity of the take-out portion of the terminal 72 is covered with hot melt 74, and the housing 76 is covered with the hot melt 74 from above.
Next molding is planned. In this case, the seal structure around the terminal 72 of the electromagnetic pickup sensor 70 is substantially the same as the seal structure around the wire harness 26 of the electromagnetic pickup sensor 50 described above, and an appropriate sealability is realized.

By the way, in order to realize a structure in which the terminal 72 is molded inside the housing 76, when molding the housing 76, it is necessary to set the terminal 72 at a predetermined position in the molding die.
Since the electromagnetic pickup sensor 70 uses two terminals 72 to form a positive electrode terminal and a negative electrode terminal, if they are independent of each other, it is necessary to set the two terminals separately in the molding die. is there.

On the other hand, according to the structure in which the terminals 72 are covered with the hot melt 74 before the housing 76 is molded, the plurality of terminals 72 are connected via the hot melt 74 before the housing 76 is molded. It will be in a connected state. Therefore, in this case, it becomes possible to set them in the molding die as a group. In this sense, the sealing structure of this embodiment also has an effect that the work of setting the terminal 72 in the molding die can be facilitated.

By the way, FIG. 11 shows a seal structure in the case where the hot melt 78 is molded by being closely attached to the outside of the housing 76. As described above, since the polyamide resin that constitutes the hot melt 78 has adhesiveness, it is possible to secure the desired sealability even with this structure.

However, in this structure, since the molding pressure of the housing 76 does not act on the hot melt 78, in order to ensure the sealing property between the hot melt 78 and the wire harness 26, the above-mentioned FIGS. It is disadvantageous to the structure shown in. Therefore, in order to secure the desired sealability by the structure shown in FIG. 11, it is necessary to take measures such as increasing the size of the hot melt 74, which causes a disadvantage in cost. From this point of view, as the seal structure using the hot melt, a structure in which the hot melt is contained inside the housing is preferable.

By the way, the seal structures shown in FIGS. 1 to 10 are all structures for ensuring a desired sealability in the electromagnetic pickup sensor, but the seal structure according to the present invention is applied to the electromagnetic pickup sensor. The structure is not limited, but includes a portion to be exposed to the outside of the housing and a portion to be housed inside the housing, and a structure that requires an appropriate sealing property around the portion to be exposed. Widely applicable.

[0078]

As described above, according to the first aspect of the invention, since the seal portion made of the thermoplastic elastomer is formed around the exposed portion, the housing is formed by molding and the periphery of the exposed portion is formed. The proper waterproofness can be ensured. Therefore, according to the seal structure of the member according to the present invention, the housing can be molded without any adverse effect, which is higher than the conventional structure in which the sealability is secured by using the O-ring or the like. It is possible to secure desired sealability while realizing productivity.

Further, according to the second aspect of the present invention, since the seal portion made of the adhesive thermoplastic resin is formed around the exposed portion, the housing is formed by molding and the periphery of the exposed portion is formed. The proper waterproofness can be ensured. Therefore, even with the seal structure of the member according to the present invention, it is possible to secure desired sealability while achieving excellent productivity, as in the case of the above-mentioned invention.

According to the third aspect of the present invention, the housing for covering the electromagnetic coil and the yoke is formed by molding, and the electromagnetic pickup portion is exposed to the outside of the housing while ensuring a proper sealing property around the housing. Can be made. Therefore, according to the seal structure of the present invention, it is possible to secure a desired sealing property around the electromagnetic pickup portion while molding the housing by molding.

According to the fourth aspect of the present invention, the cover body covers not only the electromagnetic pickup portion of the yoke but also the electromagnetic coil. Therefore, a suitable protective film against the molding pressure of the housing is formed around the winding of the electromagnetic coil, and a welded portion between the housing and the cover body is widely formed around the electromagnetic coil. Therefore, according to the member seal structure of the present invention, in addition to the advantages obtained by the invention described in claim 3, it is possible to reliably prevent damage to the winding wire when the housing is molded, and , It is used to hold the sensor body in the molding die when molding the housing, and as a result, it is possible to secure appropriate waterproofness around the part exposed to the outside of the housing. Obtainable.

According to the fifth aspect of the present invention, while the housing covering the sensor body is formed by molding, the wire harness connected to the sensor body is exposed to the outside of the housing while ensuring an appropriate sealing property. Can be made. Therefore, according to the seal structure of the present invention, it is possible to secure desired sealability around the exposed portion of the wire harness while molding the housing by molding.

[Brief description of drawings]

FIG. 1 is a front cross-sectional view of an electromagnetic pickup sensor adopting a member seal structure according to an embodiment of the present invention.

FIG. 2 is a front sectional view showing, in an enlarged manner, a part of a cover body used for the seal structure of the member of the present embodiment.

FIG. 3 is an enlarged front sectional view of a grommet used for the seal structure of the member of the present embodiment.

FIG. 4A is a front view of the electromagnetic pickup sensor of this embodiment. FIG. 4B is a plan sectional view of the housing and the cover body of the electromagnetic pickup sensor of this embodiment.

FIG. 5 is a front cross-sectional view showing, in an enlarged manner, a part of a cover body used in a member seal structure according to another embodiment of the present invention.

FIG. 6 is a front sectional view of an electromagnetic pickup sensor adopting a member seal structure according to another embodiment of the present invention.

FIG. 7 (A) is a perspective view showing an example of a state in which a wire harness is covered with hot melt. FIG. 7B is a cross-sectional view showing an example of a state in which the wire harness is covered with hot melt. FIG. 7C is a sectional view showing an example of a state in which the wire harness is covered with hot melt and a housing.

FIG. 8A is a perspective view showing another example of a state in which the wire harness is covered with hot melt. FIG. 8 (B)
FIG. 6 is a cross-sectional view showing another example of a state in which the wire harness is covered with hot melt. FIG. 8C is a sectional view showing another example of a state in which the wire harness is covered with hot melt and a housing.

FIG. 9A is a cross-sectional view showing an example of a state in which the periphery of the electromagnetic pickup unit is covered with hot melt. Figure 9
(B) is a cross-sectional view showing an example of a state in which the periphery of the electromagnetic pickup unit is covered with hot melt and a housing.

FIG. 10 is a front sectional view of an electromagnetic pickup sensor adopting a member seal structure according to another embodiment of the present invention.

FIG. 11 is a cross-sectional view showing an example of a seal structure configured by using hot melt.

[Explanation of symbols]

 10, 50, 70 Electromagnetic pickup sensor 12 Electromagnetic coil 14 Bobbin 16 Winding wire 22, 40, 64 Cover body 22a, 24a, 24b, 40a Seal part 24 Grommet 26 Wire harness 26a, 26b Signal line 28 Yoke 28a Electromagnetic pickup part 30, 76 Housing 52, 58, 74, 78 Hot melt 54a, 54b, 60a, 60b Adhesive interface 56, 62 Welding layer 72 Terminal 74 Connector

Claims (5)

[Claims] 1. An inner member having an exposed portion exposed to the outside, a cover body made of a thermoplastic elastomer and provided with a seal portion surrounding the exposed portion, and a mold at a temperature temporarily exceeding the melting point of the cover body. A sealing structure for a member, comprising: a housing that is formed and covers the internal member in a state where the exposed portion is exposed to the outside. 2. An inner member having an exposed portion exposed to the outside, a cover body made of an adhesive thermoplastic resin and provided with a seal portion surrounding the exposed portion, and a melting point of the cover body temporarily. A sealing structure for a member, comprising: a housing that is molded at a temperature exceeding the temperature and covers the internal member with the exposed portion exposed to the outside. 3. The seal structure for a member according to claim 1, wherein the inner member is formed by winding a conductive wire around a bobbin.
A sensor body having an electromagnetic coil having a hollow portion and a magnetic member having an electromagnetic pickup portion at one end, the yoke being inserted into the hollow portion of the electromagnetic coil, wherein the exposed portion is an electromagnetic pickup of the yoke. A seal structure for a member, which is characterized by being a part. 4. The member seal structure according to claim 3, wherein the cover body is formed so as to cover the outer circumference of the electromagnetic coil. 5. The seal structure for a member according to claim 1, wherein the inner member is formed by winding a wire around a bobbin.
A sensor main body having an electromagnetic coil having a hollow portion and a magnetic member having an electromagnetic pickup portion at one end, the yoke being inserted into the hollow portion of the electromagnetic coil, wherein the exposed portion is connected to the sensor main body. A seal structure for a member, which is an improved wire harness.