JP2533893Y2 - Electromagnetic rotation sensor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic rotation sensor used as a crank angle sensor for detecting the rotation speed of an internal combustion engine for an automobile, for example.

[0002]

2. Description of the Related Art For example, in an internal combustion engine provided with an electronically controlled fuel injection device, a crank angle as a rotation speed sensor for detecting a rotation angle of a crankshaft in order to control a fuel injection amount, an ignition timing, and the like. A sensor is provided (see JP-A-59-155540).

As such a crank angle sensor, a plurality of protrusions are formed on a ferromagnetic rotor connected to a crank shaft or a rotating shaft (cam shaft or the like) interlocked with the crank shaft, and the crank angle is set facing the protrusions. There is a so-called electromagnetic type in which a sensor is provided and the rotation angle of the crankshaft is detected based on a back electromotive force generated in the crank angle sensor due to a change in the amount of magnetic flux when the projection passes near the crank angle sensor.

[0004] That is, as shown in FIG. 2, a rotating plate 21 made of a magnetic material is supported by a rotating shaft 22.
Reference numeral 22 is connected to a crankshaft of an internal combustion engine (not shown). A plurality of projections 23 are formed on the surface at a unit angle in the radial direction. Then, the projection 23 crosses the magnetic flux of the iron core of the electromagnetic crank angle sensor 20, which will be described later, so that a one-cycle AC signal is generated in the coil of the electromagnetic crank angle sensor 20. It is extracted as output.

Here, the electromagnetic crank angle sensor 20 will be described with reference to FIG. The main body 4 of the electromagnetic crank angle sensor 20 is formed of an insulating fiber-reinforced resin material in a stepped cylindrical shape so as to surround a permanent magnet 6 and the like described later, and a coil bobbin 5 is integrally formed at the tip end thereof. Further, a detection coil 9 to be described later is wound directly outside the coil bobbin 5. A seal groove 4A for the O-ring 12 and an annular groove 4B to be described later are formed on the outer peripheral side of the main body 4, and a protective cap 10 to be described later is crimped and fixed to the annular groove 4B. .

A permanent magnet 6 formed in a short columnar shape and a core top 7 formed in a stepped columnar shape by a magnetic material such as soft magnetic iron are disposed in the main body 4. A large-diameter portion 7A located on the base end side and having substantially the same outer shape as the permanent magnet 6, and a small-diameter portion 7B extending coaxially from the large-diameter portion 7A and inserted into the coil bobbin 5. The distal end face 7C side of the portion 7B slightly protrudes from the coil bobbin 5 and is arranged close to the rotating plate 21. Further, the core bottom 8 in contact with the other end face of the permanent magnet 6 is formed in a columnar shape from a magnetic material such as electromagnetic soft iron, so that the magnetic flux density of the permanent magnet 6 is increased.

When the core top 7, the permanent magnet 6, and the core bottom 8 are inserted, the opening side of the main body 4 is closed by a closing member 13 made of a thermosetting resin material such as an epoxy resin. Dust and the like are prevented from entering the main body 4. In addition, a protective cap formed in a closed cylindrical shape with a non-magnetic stainless steel plate, etc.
10 is caulked and fixed to the annular groove 4B so as to cover the tip surface 7C of the core top 7, the detection coil 9 and the main body 4,
The permanent magnet 6 and the detection coil 9 in the main body 4 together with the O-ring 12
Are protected from external water.

The detection coil 9 wound around the coil bobbin 5 is connected to a control unit via a lead wire (not shown). When the rotation plate 21 rotates, the projection 23 of the rotation plate 21 made of a magnetic material is turned on. Are sequentially approached and separated from the distal end surface 7C of the core top 7, whereby the magnetic flux of the core top 7 changes and the detection coil 9
Generates an induced electromotive force. Then, the induced electromotive force is output to the control unit via the terminal 14 and the lead wire as a detection signal due to the rotation of the rotating plate 21.

[0009]

Here, in the conventional electromagnetic crank angle sensor 20, the stepped cylindrical main body 4 in which the coil bobbin 5 is integrally disposed at the tip end side is formed by injection molding. It is formed integrally. By the way, in injection molding, an upper mold and a lower mold are combined, a resin material is injection-molded in a space between the molds, and a product is taken out after separating the upper mold and the lower mold. The projection 16 (so-called parting line) as shown in FIG.
16) is formed.

Here, since the detection coil 9 is directly wound around the outside of the coil bobbin 5, the innermost layer 9a of the detection coil 9 comes into direct contact with the parting line 16, and the detection is performed due to aging or the like. When the enamel coating of the coil 9 is peeled and short-circuited, or the wire is broken, there is a possibility that the rotation speed cannot be accurately detected.

The present invention has been made in view of such circumstances, and has as its object to provide an electromagnetic rotation sensor capable of preventing a detection coil from directly contacting a coil bobbin and improving quality.

[0012]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an electromagnetic rotation sensor for outputting a signal generated on a detection coil wound around a coil bobbin formed by using a mold having a center cylinder portion that is half-split. In the above, the coil bobbin and the detection coil
Between the sensor coil and the detection coil.
The material was wound and interposed .

[0013]

According to the above construction, the coil bobbin and the detection coil are provided.
And a thread-like member is wound and interposed between
When forming a coil bobbin using a half-split mold, even if a parting line is formed in the central cylindrical portion of the coil bobbin, the parting line comes into contact with the thread-like member, and the detection coil is Direct contact with the parting line is prevented.

The thread member is substantially the same as the detection coil .
Since the detection coil has a diameter, when the detection coil is wound, the detection coil is located between the adjacent thread-like members, so that the winding state of the detection coil can be prevented from being disturbed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below based on an electromagnetic crank angle sensor 1 shown in FIG. Note that the same elements as those of the conventional example shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted. The coil bobbin 5 of the electromagnetic crank angle sensor 1 is integrally formed by injection molding.

A nylon thread 2 having a diameter (about 50 μm) having a diameter equal to the diameter of the detection coil 3 is provided on the bottom 5 a, which is the central cylindrical portion of the coil bobbin 5.
a is wound from the large-diameter portion 7A side toward the tip end surface 7C side, and after covering the entire bottom portion 5a, is wound so as to overlap the nylon thread 2 and return to the large-diameter portion 7A side again. I have. The detection coil 3 is wound around the nylon thread 2.

Thus, the first winding 2A of the nylon thread 2 comes into contact with the parting line 16 formed when the coil bobbin 5 is injection-molded, and the detection coil 3 directly contacts the parting line 16. Contact is prevented. Also, since the diameter of the nylon thread 2 is equal to that of the detection coil 3, when the detection coil 3 is wound, the first turn of the detection coil 3 is located between the adjacent nylon threads 2, and The winding state of the coil 3 is not disturbed.

Accordingly, it is possible to prevent the detection coil 3 from directly contacting the parting line 16 formed on the coil bobbin 5 and the like, and to prevent the detection coil 3 from being disconnected, and to accurately detect the rotation speed. This makes it possible to improve the quality of the electromagnetic rotation sensor 1. In this embodiment, the configuration is such that the nylon yarn 2 starts to be wound from the large-diameter portion 7A side of the bottom portion 5a, returns again, and finishes winding, so that the end portion of the nylon yarn 2 can be easily treated, and the manufacturing is easy. Workability is also good.

Further, in the present embodiment, a nylon thread 2 having a diameter substantially equal to that of the detection coil 3 is wound as a thread-shaped member. It is good also as a structure which winds the coil wire which does not produce.

[0020]

[Effects of the Invention] As described above, according to the present invention,
A thread-like member is wound between the coil bobbin and the detection coil.
And insert the coil bobbin during molding.
No matter the computing line formed, it is possible to prevent the occurrence of disconnection of the detection coil, has, it is possible to improve the quality of the electromagnetic rotary sensor. Also, the coil bobbin and detection coil
The thread member interposed between the coil and the coil is almost the same as the detection coil
The diameter of the sensor coil,
Can be prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electromagnetic crank angle sensor showing an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a conventional electromagnetic crank angle sensor.

FIG. 3 is a longitudinal sectional view of an electromagnetic crank angle sensor according to a conventional example.

FIG. 4 is a schematic sectional view of a coil bobbin for explaining the problem of the present invention.

[Explanation of symbols]

 Reference Signs List 1 electromagnetic crank angle sensor 2 nylon thread 3 detection coil 5 coil bobbin 5a bottom 16 parting line

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 2-45417 (JP, U) JP-A 62-36516 (JP, U) JP-A 1-133706 (JP, U) JP-A 64-64 39606 (JP, U) Actually open 1951-9246 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A electromagnetic rotation sensor central cylindrical portion outputs a signal generated in wound detection coil to have been coil bobbin formed by using a mold of half-friendly, the Koirubo
The diameter between the bin and the detection coil is approximately the same as that of the detection coil.
An electromagnetic rotation sensor characterized by winding and interposing a thread-like member having the following .