JPH0590907U - Coil bobbin - Google Patents

Abstract

(57) [Abstract] [Purpose] When resin molding the outer peripheral surface 23 of the intermediate portion of the coil bobbin 2 with a divided die, it is possible to prevent cutting of the coil due to burrs or steps caused on the product by the die dividing surface. [Structure] Molded using four-piece molds C1 to C4,
Mold dividing surfaces P1 to P4 are formed on the outer peripheral surface 23 of the intermediate portion of the coil bobbin 2.
A concave portion (V-shaped groove) 24 is simultaneously formed along the line of intersection with.
Therefore, burrs or steps are generated in the recess 24, so that they do not come into contact with the coil.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a resin-made coil bobbin having a collar at both ends of a cylindrical body and a coil wound around an outer peripheral surface of an intermediate portion.

[0002]

[Prior Art]

 This type of coil bobbin is used, for example, in an electromagnetic pickup type crank angle sensor of an engine. FIG. 5 shows the structure of the electromagnetic pickup type crank angle sensor. Explaining this, a resin coil bobbin 2 is arranged on the outer circumference of the tip of a magnetic core 1. The coil bobbin 2 has flanges 21 and 22 at both ends of a cylindrical body, and the coil 3 is wound around the outer peripheral surface 23 of the intermediate portion. Both ends of the coil 3 are connected to the two terminals 4a and 4b, respectively. In addition, 5 and 6 are insulating resin parts, 7 is a connector resin part, and 8 is a cover.

Therefore, the magnetic field of the iron core 1 is traversed by the protrusion formed on the signal disk plate which rotates in synchronization with the crankshaft, so that an induced current is generated in the coil 3, which causes the terminals 4a and 4b to move. It is taken out through the outside.

[0004]

[Problems to be solved by the device]

 By the way, in this type of coil bobbin 2, due to the fact that the coil bobbin 2 is molded into a shape having the flanges 21 and 22 at both ends, when molding the intermediate portion outer peripheral surface 23 around which the coil is wound, as shown in FIG. C1 and C2 are used. The arrow in the figure indicates the direction of die removal.

Therefore, due to the presence of the mold dividing surface (parting line) P, a burr as shown in FIG. 7 and a step due to a mold deviation as shown in FIG. 8 are generated in the product, and a coil is wound around this. Then, there is a problem that the coil winding may be damaged or cut at the burr or the step. In particular, in an electromagnetic pickup type crank angle sensor, it is necessary to increase the number of turns of the coil in order to increase its output. For this reason, the coil winding must be increased without increasing the size of the coil bobbin. It is necessary to make it thin, and since thin wires with a diameter of around 50μ are currently used, they tend to be easily cut.

As a countermeasure for this, after molding, deburring is performed, tape is wound, and then a coil is wound, but the number of man-hours increases, which also causes a problem of cost increase. there were. The present invention has been made in view of such conventional problems, and an object thereof is to provide a coil bobbin capable of solving problems such as burrs without requiring post-molding treatment.

[0007]

[Means for Solving the Problems]

 Therefore, the present invention is a resin coil bobbin having a collar at both ends of a cylindrical body and a coil wound around the outer peripheral surface of the intermediate portion, wherein the outer peripheral surface of the intermediate portion is divided into a plurality of portions in the circumferential direction. In the case of molding with a mold, a recess is formed on the outer peripheral surface of the intermediate portion along the line of intersection with the mold dividing surface.

[0008]

[Action]

 In the above configuration, a burr or a step is formed on the outer peripheral surface of the intermediate portion along the line of intersection with the mold dividing surface, but this part is formed as a recess in advance, and a burr or a step is generated in the recess. Therefore, if the coil is wound on the outer peripheral surface of the intermediate portion, the burr or step does not contact the coil, and the burr or step prevents the coil from being scratched or cut.

[0009]

【Example】

 An embodiment of the present invention will be described below. As shown in FIGS. 1 and 2, the coil bobbin 2 has collars 21 and 22 at both ends of a cylindrical body, and a coil (not shown) is wound on the outer peripheral surface 23 of the intermediate portion. The concave portion (V-shaped groove) 24 is formed along the line of intersection with the surface.

In this case, as the molding die, as shown in FIG. 3, molds C1 to C4 divided into four at 90 ° intervals in the circumferential direction are used, and the outer peripheral surface 23 of the intermediate portion and the mold division surfaces P1 to P4 are formed. Four recesses (V-shaped grooves) 24 are formed along the respective intersection lines. That is, the concave portions 24 are formed by resin molding by forming convex portions for forming the concave portions 24 on the product in the four divided molds C1 to C4. The arrow in the figure indicates the direction of die removal.

In view of the relationship with the punching, it is preferable that the recess 24 has a V-shaped cross-section, and the angle θ is preferably 90 ° or more. Further, the burrs or steps that occur are usually 10 to 20 .mu.m, and the maximum is about 40 .mu.m. Therefore, the depth D of the recess 24 may be about 50 .mu.m. Further, it is desirable to provide a suitable radius on the connecting portion E between the recess 24 and the outer peripheral surface.

Therefore, as shown in FIG. 4, even if, for example, a burr B is formed along the line of intersection with the mold dividing surface, this portion is previously formed as the recess 24, and the burr B is formed in the recess 24. Therefore, if the coil 3 is wound around the outer peripheral surface 23 of the intermediate portion, the burr B does not come into contact with the coil 3 and damage or cutting of the coil 3 due to the burr is prevented.

[0013]

[Effect of the device]

 As described above, according to the present invention, even if a burr or a step is generated due to the presence of the mold dividing surface, it does not come into contact with the coil, and damage or cutting due to the burr or the step is prevented. Moreover, since the coil bobbin can be processed during resin molding, there is no need for post-molding processing, and cost increase due to increased man-hours can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of a coil bobbin showing an embodiment of the present invention.

FIG. 2 is a sectional view of the main part of the above.

FIG. 3 is a diagram showing a molding die.

FIG. 4 is a diagram showing a state in which a coil is wound around the product.

FIG. 5 is a diagram showing a structure of an electromagnetic pickup type crank angle sensor.

FIG. 6 is a view showing a conventional molding die.

[Figure 7] Diagram showing an example of product defects

[Figure 8] Diagram showing an example of product defects

[Explanation of symbols]

 1 Iron core 2 Coil bobbin 3 Coil 21, 22 Tsuba 23 Intermediate outer peripheral surface 24 Recessed portion (V-shaped groove) C1-C4 type P1-P4 type split surface

Claims (1)

[Scope of utility model registration request] 1. A resin coil bobbin having a collar at both ends of a cylindrical body, and a coil wound around an outer peripheral surface of an intermediate portion, wherein the outer peripheral surface of the intermediate portion is formed by a mold divided into a plurality of pieces in the circumferential direction. The coil bobbin according to claim 1, wherein a recess is formed on the outer peripheral surface of the intermediate portion along a line of intersection with the mold dividing surface.