JPH04102466U - Electromagnetic rotation sensor - Google Patents

Abstract

(57) [Summary] [Purpose] The present invention prevents the formation of a gap between the large diameter portion of the core member and the bottom of the housing portion, thereby preventing resin from entering the tip side of the core member. do. [Structure] A cylindrical seal portion 24 is provided on the bottom portion 23B of the housing portion 23, and the large diameter portion 6A of the core member 6 is brought into contact with the upper end surface 24A of the seal portion 24. Therefore, the caulking portion 9A of the protective cap 9 and the thermal caulking portion 2 of the housing portion 23
3A, when the core member 6, permanent magnet 5, etc. are clamped and fixed from the axial direction, the large diameter portion 6A of the core member 6 presses the upper end surface 24A of the seal portion 24 to lower the surface roughness. is formed, and the large diameter portion 6A of the core member 6 and the seal portion 24
By improving the sealing performance between the resin 1 and the upper end surface 24A,
2 can be prevented from entering the tip side of the core member 6.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention can be used, for example, in crank angle sensors that detect the rotation speed of automobile engines. The present invention relates to a suitable electromagnetic rotation sensor.

0002

[Conventional technology]

Figure 2 shows a crank angle sensor as an example of a conventional electromagnetic rotation sensor. show.

0003 In the figure, 1 is a crank angle sensor, and 2 is an insulating fiber-reinforced resin material. The crank angle sensor 1 is formed into a stepped cylindrical shape so as to surround the permanent magnet 5, etc. mentioned above. The figure shows a casing constituting the main body of the casing 2, and an insertion hole 3A is provided on the tip side of the casing 2. A coil bobbin 3 having a coil bobbin 3 is integrally formed, and the base end side communicates with the coil bobbin 3. A cylindrical housing portion 4 with a bottom is formed. The base end side of the casing 2 is It is fixed to the frame (not shown) of the engine, etc., and the tip side of the core member 6, which will be described later, is magnetically attached. Positioned on the outer periphery of a rotating plate (not shown) formed into a toothed disc shape using a material. It has become so. Further, on the outer peripheral side of the casing 2, an O-ring 10, which will be described later, is provided. A protective cap 9 and a shield member 11, which will be described later, are connected to the seal groove 2A into which the An annular groove 2B, etc., which is fixed by caulking, is formed in the opening of the housing part 4. With the core member 6, permanent magnet 5, and iron core member 7 inserted inside, fix by thermal caulking. A thermally caulked portion 4A is formed.

0004 5 is a permanent magnet provided in the housing part 4 and formed in a short cylindrical shape; 6 is an electromagnetic soft magnet; The core member 6 is a stepped cylindrical core member made of a magnetic material such as iron. is located on the base end side, the back side is in contact with the lower end surface side of the permanent magnet 5, and the front outer peripheral side is A large diameter portion 6A abuts on the bottom 4B of the housing portion 4, and a large diameter portion 6A extending coaxially from the large diameter portion 6A. , and a small diameter portion 6B inserted into the insertion hole 3A of the coil bobbin 3. The tip surface 6C side of the diameter portion 6B slightly protrudes from the coil bobbin 3 and is attached to the protective cap 9. are in contact.

[0005] Reference numeral 7 indicates an iron core member located within the housing portion 4 and in contact with the upper end surface side of the permanent magnet 5. , the iron core member 7 is formed of a magnetic material such as electromagnetic soft iron into a long cylindrical shape. The magnetic flux density of the permanent magnet 5 is further increased.

[0006] 8 is located on the radially outer side of the small diameter portion 6B of the core member 6 and is wound around the coil bobbin 3. The detection coil 8 is connected to the control unit via a lead wire. (none of which are shown). The detection coil 8 has a magnetic As the rotating plate made of the material rotates, the magnetic flux from the permanent magnet 5 passing through the core member 6 changes. When the rotation occurs, an induced electromotive force is generated by electromagnetic induction, which is used as a rotation signal for the rotating plate. The output signal is then output to the control unit via a lead wire.

[0007] 9 is a case that covers the tip surface 6C of the core member 6 and the outer peripheral surface of the detection coil 8. The storage is attached to the ring 2 and is shaped like a covered cylinder made of non-magnetic stainless steel plate. This protective cap 9 has a caulking part 9A on the opening side of the casing 2. By caulking and fixing it to the annular groove 2B, it is prevented from coming off from the casing 2, Protect the core member 6, permanent magnet 5, detection coil 8, etc. together with the O-ring 10 from outside rainwater and impact. It is designed to protect against attacks.

[0008] Reference numeral 11 indicates a magnetic shielding member fitted to the outer circumferential side of the protective cap 9. The shield member 11 is made of a magnetic material such as iron and has a cylindrical shape, and is This prevents noise such as electromagnetic waves from entering the detection coil 8 and the like.

[0009] Reference numeral 12 is filled in the opening side of the accommodating portion 4, and is made of thermosetting resin material such as epoxy resin. The resin 12 is used as a sealing member to seal the opening of the accommodating portion 4. It is designed to prevent rainwater, dust, etc. from entering the housing part 4 from outside. Ru.

0010 The conventional crank angle sensor has the above-mentioned configuration, and has a coil bolt. Insert the core member 6 into the insertion hole 3A of the bottle 3, and insert the core member 6 and the permanent magnet into the housing part 4. 5 etc., and insert the caulked part 9A of the protective cap 9 into the annular groove 2B of the casing 2. It is fixed by caulking, and the heat caulking portion 4A of the housing portion 4 is thermally caulked. Next, open the storage section 4. The mouth side is filled with resin 12 and sealed. This allows the core member 6 and the like to be placed in the housing section 4. It is assembled by being clamped and fixed from the top and bottom inside, and is installed near the rotating plate. It will be done. When the engine starts, the rotating plate is integrated with the crankshaft (not shown). When rotates, the teeth of the rotating plate made of magnetic material gradually approach the tip surface of the core member 6. , so that the magnetic field passing through the core member 6 from the permanent magnet 5 is The flux changes, and an induced electromotive force is generated in the detection coil 8 due to electromagnetic induction. And this The electromotive force is controlled as a detection signal that increases or decreases depending on the approach or separation of the rotating plate teeth. output to the control unit and used as a crank angle signal to detect engine speed. I can stay.

[0011]

[Problem that the idea aims to solve]

By the way, in the conventional technology described above, the casing 2 and the coil bobbin 3 Since they are integrally molded, it is difficult to finish the surface inside the housing part 4. The surface roughness of 4B becomes high, and the size of the bottom 4B of the housing part 4 and the core member 6 increases as shown in FIG. A gap S may be created between the diameter portion 6A.

0012 For this reason, in the prior art described above, the core member is 6. Even if you try to fix the permanent magnet 5 and the iron core member 7, it will not be possible to fix them completely. There is no problem that scratches or scratches may rattle inside the housing section 4 and cause abnormal noise or damage. There is a problem. In addition, if the thermal caulking of the thermal caulking part 4A becomes incomplete, pour the resin 12. When filling, the resin 12 flows from the outer circumferential side of the iron core member 7 etc. through the gap S. and flows into the coil bobbin 3 between the coil bobbin 3 and the protective cap 9, It enters between the distal end surface 6C of the core member 6 and the protective cap 9, and the protective cap 9 is The caulking part 9A becomes loose and the core member 6 shakes, causing noise and greatly reducing detection accuracy. There is a problem with the decline.

[0013] The present invention was developed in view of the problems of the prior art described above. This prevents a gap from forming between the large diameter part and the bottom of the storage part, allowing the resin to Prevents intrusion between the tip surface and the protective cap, improving detection ability, reliability, and service life. The purpose is to provide an electromagnetic rotation sensor that can improve the be.

[0014]

[Means to solve the problem]

The feature of the configuration adopted by this invention to solve the above-mentioned problems is that the casing A cylindrical seal portion is provided in the accommodating portion, protruding from the bottom of the accommodating portion toward the opening side, The structure is such that the proximal end side of the core member is brought into contact with the distal end side of the seal portion.

[0015]

[Effect]

By bringing the proximal end of the core member into contact with the distal end of the seal, the This improves the sealing performance with the core member, and the sealing member extends from the opening side of the accommodating part to the tip of the core member. It can prevent leakage to the side.

[0016]

【Example】

Hereinafter, an embodiment of the present invention will be described based on FIG. 1. In addition, in the example, the above-mentioned The same components as those in the prior art shown in FIG. 2 are given the same reference numerals, and their explanations are omitted. shall be taken as a thing.

[0017] In the figure, 21 is a casing used in this example in place of the casing 2 according to the conventional technology. The casing 21 has an insertion hole 22A on the tip side, as in the prior art. A coil bobbin 22 having a coil bobbin 22 is integrally formed therein, and a coil bobbin 22 is connected to the coil bobbin 22 on the base end side. A cylindrical accommodating portion 23 with a bottom is formed. Here, the accommodating portion 23 is constructed using conventional technology. It is formed into a cylindrical shape with a bottom, almost the same as the housing part 4 mentioned in the section, and there is a thermally caulked part on the opening side. 23A is provided, but the bottom portion 23B of the housing portion 23 is provided with a seal, which will be described later. A portion 24 is integrally formed.

[0018] 24 is located on the outer circumferential side of the insertion hole 22A of the coil bobbin 22 and is located at the bottom of the housing portion 23. 23B, and protrudes from the bottom 23B toward the opening side. The seal portion 24 shown in FIG. It is in contact with the front side of the diameter portion 6A. The seal portion 24 is attached to the protective cap 9. The core member 6 and the like are held between the caulking portion 9A and the thermal caulking portion 23A of the housing portion 23. When the upper end surface 24A is pressed and fixed by the large diameter portion 6A of the core member 6, the upper end surface 24A is pressed and fixed. The surface roughness is reduced and the resin 12 is prevented from leaking to the tip surface 6C side of the core member 6. It looks like this.

[0019] The crank angle sensor according to this embodiment has the above-mentioned configuration, and its basics are as follows. Regarding the operation, there is no particular difference from that according to the prior art.

[0020] However, in this embodiment, a cylindrical seal portion 24 is provided at the bottom portion 23B of the storage portion 23. , a configuration in which the large diameter portion 6A of the core member 6 is brought into contact with the upper end surface 24A of the seal portion 24. Therefore, the caulking part 9A of the protective cap 9 and the heat caulking part 23A of the housing part 23 are used. When the core member 6 etc. is clamped and fixed, the large diameter portion 6A of the core member 6 seals. The surface roughness can be reduced by pressing the upper end surface 24A of the portion 24 so as to crush it. , a gap is created between the upper end surface 24A of the seal portion 24 and the large diameter portion 6A of the core member 6. It is possible to prevent this and greatly improve sealing performance.

[0021] Therefore, according to this embodiment, the heat of the caulked part 9A of the protective cap 9 and the housing part 23 is The core member 6, permanent magnet 5, and iron core member 7 are inserted into the housing part 23 by the caulking part 23A. It can be fixed in a stable state inside. As a result, when injecting and filling the resin 12, The resin 12 passes from the opening side of the housing portion 23 to the outer peripheral side of the iron core member 7 and the like to the core portion. Since it can effectively prevent leakage to the tip surface 6C side of the material 6, the permanent magnet 5 and the core part It can prevent material 6 etc. from rattling and being damaged, and it can effectively prevent noise from occurring. By preventing this, detection ability, reliability, etc. can be significantly improved.

[0022] In addition, in the embodiment described above, the seal portion 24 is provided integrally with the bottom portion 23B of the accommodating portion 23. This is described as having a cylindrical shape protruding from the bottom portion 23B toward the opening side. However, the present invention is not limited to this. For example, the seal portion may be made of resin material, metal material, etc. The seal portion is formed into a long cylindrical shape, and a fixing means such as adhesive is attached to the bottom portion 23B of the housing portion 23. It is also possible to form the seal part into another shape such as a rectangular tube shape. It's okay.

[0023] Further, in the above embodiment, the coil bobbin 22 is integrally formed with the casing 21. However, instead of this, the casing 21 and the coil bobbin 22 can be made into separate parts. They may be made of a material and both may be integrally fixed.

[0024] Further, in the above embodiment, the crank angle sensor was explained as an example, but the present invention is not limited to this, for example, various electromagnetic circuits such as rotation sensors that detect the number of rotations of wheels. It can also be applied to rotational sensors.

[0025]

[Effect of the idea]

As detailed above, according to the present invention, the bottom of the housing part of the casing is A seal portion is provided that protrudes toward the opening side, and a core member is placed on the tip side of the seal portion. Since the proximal end sides are brought into contact, the distal end side of the seal part and the proximal end side of the core member It can improve the sealing performance between the core member and prevent the sealing member from entering the tip side of the core member. In addition, the core member, etc. can be fixed in a stable state within the housing part, and the core member, etc. can be effectively prevent damage and noise caused by The detection ability and reliability of the magnetic rotation sensor can be improved.

[Brief explanation of drawings]

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

FIG. 2 is a longitudinal cross-sectional view of a crank angle sensor showing the prior art.

3 is an enlarged vertical sectional view of the main part of FIG. 2 showing a state in which a gap is created between the bottom of the accommodating portion and the large diameter portion of the core member.

[Explanation of symbols]

5 Permanent magnet 6 Core member 8 Detection coil 9 Protective cap 12 Resin (sealing member) 21 Casing 22 Coil bobbin 23 Housing section 23B Bottom 24 Seal part 24A Upper end surface (tip side)

Claims (1)

[Scope of utility model registration request] Claim 1: A casing made of an insulating resin material, the distal end of which is a coil bobbin, and the proximal end of which is a bottomed cylindrical accommodating portion that communicates with the coil bobbin; a core member that is inserted together with a magnet, whose distal end side is inserted into the coil bobbin of the casing, and whose proximal end side is in contact with the bottom of the accommodating portion of the casing; A detection coil wound around a coil bobbin of the casing, a covered cylindrical protective cap provided on the casing so as to cover the detection coil and the distal end surface of the core member, and a protective cap of the accommodating portion. In an electromagnetic rotation sensor comprising a sealing member for sealing an opening, the accommodating portion of the casing is provided with a cylindrical seal portion protruding from the bottom of the accommodating portion toward the opening side. An electromagnetic rotation sensor characterized in that the proximal end of the core member is brought into contact with the distal end of the seal portion.