JP2003266495A - Injection mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mold a resin product by a common mold even if there is a variation in the shape or angle of a fixing part for fixing the resin product. <P>SOLUTION: A core mold 13 is incorporated in the space between a fixed mold 11 and a movable mold 12 and a flange 6 being the fixing part for fixing the resin product is molded using the core mold 13. Accordingly, the shape or angle of the flange 6 can be freely altered only by altering the inner shape of the core mold 13 or the incorporation angle of the core mold 13 to the inner space between the fixed mold 11 and the movable mold 12. Therefore, the common mold can be used with respect to the injection mold 20 comprising the fixed mold 11 and the movable mold 12. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die, and is particularly suitable for forming a sensor housing by insert molding a detector having directivity in the detection direction. .

[0002]

2. Description of the Related Art For example, when a rotation detecting device is constituted by a magnetic sensor consisting of a bias magnet and a magnetoresistive element, and a rotor arranged facing the magnetic sensor and having gear teeth formed on the outer circumference thereof, the magnetic resistance In order to apply a bias magnetic field that changes depending on the rotational position of the rotor to the element, the magnetoresistive element needs to be arranged along the rotational direction of the rotor. As described above, in the magnetic sensor using the magnetoresistive element, it is necessary to dispose the magnetoresistive element along the direction in which the bias magnetic field to be detected swings.
It is a sensor having directivity in the detection direction.

When the housing of this magnetic sensor is formed by injection molding of resin, a detecting portion composed of a magnetoresistive element, a terminal connected to the detecting portion, and the like are arranged in a space inside an injection molding die, and the space is formed. The molten resin is injected into. At this time, a flange having a through hole for fixing the magnetic sensor is formed in the housing, and the magnetic sensor is fixed to another member by a bolt or the like using the through hole.

[0004]

However, since the fixed position of the magnetic sensor and the member to be fixed are changed when the measurement object of the rotation detecting device including the magnetic sensor and the rotating body is different, the magnetic sensor is also changed. It may be necessary to change the shape and angle of the flange that secures the.

In such a case, if a separate mold is prepared for each different shape and angle of the flange to mold the resin housing of the magnetic sensor, the cost of the mold becomes very high.

The present invention has been made in view of the above points, and even if there are variations in the shape and angle of the fixing portion for fixing the resin product to another member, the resin product can be used in common metal. An object of the present invention is to provide an injection molding die that can be molded by a mold.

[0007]

In order to achieve the above object, an injection molding die according to claim 1 comprises a fixed die and a movable die movable relative to the fixed die. In a mold for injection molding, in which a fixed mold and a movable mold are closed, a molten resin is injected into a space formed inside both molds to mold a resin product having a predetermined shape.
A nesting type is provided in which a fixing part for fixing the resin product to another member is formed, and a mold for forming the fixing part can be attached to and taken out from the internal space of the fixed mold and the movable mold. It is characterized by

As described above, by forming the fixing portion for fixing the resin product to be injection-molded with respect to other members by the nesting mold, the nesting mold is formed into the internal shape or the internal space between the fixed mold and the movable mold. Just change the mounting angle of
The shape and angle of the fixed part can be freely changed. Therefore, it is not necessary to change the mold including the fixed mold and the movable mold, and a common mold can be used.

According to a second aspect of the present invention, an engaging portion that engages with at least one of the fixed die and the movable die is formed on the outer periphery of the nesting die, and the nesting is provided in at least one of the fixed die and the movable die. It is desirable that a plurality of engaging positions of the mold with the engaging portion are set in the rotation direction of the nest mold. in this case,
Since the nesting die engages with at least one of the fixed die and the movable die, the nesting die can be securely held between the fixed die and the movable die. Further, when a plurality of engaging positions of the nesting type engaging portion are set in at least one of the fixed die and the movable die in the rotating direction of the nesting die, the angle of the fixed portion can be easily changed. .

As described in claim 3, the fixed mold has:
A push-out pin for pushing out the resin product is provided, and it is desirable that the push-out pin pushes the nesting die so that the resin product and the nesting die are integrally pushed out from the fixed die. Thereby, even when the nesting mold is used, the resin product can be easily taken out from the mold.

As described in claim 4, the resin product is
When the detector having directivity in the detection direction is insert-molded, it is particularly preferable to use the injection molding die according to the present invention. That is, the angle of the fixed part can be easily changed only when the detection part has directivity in the detection direction, because the angle of the insert-molded part of the resin product in which the detection part is insert-molded cannot be changed. The advantage of using the injection molding die of the present invention is great.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view schematically showing the structure of a rotation detecting device comprising a magnetic sensor 1 and a rotor 10 having a housing molded by an injection molding die according to this embodiment. In FIG. 1, gear teeth 10a are formed on the outer peripheral surface of a rotor 10 made of a ferromagnetic material. The rotor 10 rotates about a rotating shaft 10b.

The magnetic sensor 1 has a detection unit 4 formed of one or a plurality of magnetoresistive element (MRE) bridges,
The detector 4 is formed on the substrate 5. The substrate 5 including the detection unit 4 is held at a position where a part of the substrate 5 is inserted into the hollow bias magnet 3. The bias magnet 3 faces the outer peripheral surface of the rotor 10 on which the gear teeth 10 a are formed, and is arranged such that the central axis of the bias magnet 3 faces the rotation axis of the rotor 10. Although not shown, the substrate 5 on which the detection unit 4 including the MRE bridge is formed is mounted on a lead frame made of copper or the like and molded by a thermosetting resin such as epoxy.

The detector 4 will now be described. One or a plurality of MRE bridges constituting the detector 4 are
Ferromagnetic material (Ni-Co) having anisotropic effect of magnetoresistance
It is formed by forming a thin film of an alloy, a Ni—Fe alloy or the like) on a substrate by a method such as vapor deposition and etching the film into a predetermined pattern by a photolithography technique.
Specifically, the MRE bridge is composed of two MREs, and each MRE is formed in a comb-shaped pattern by connecting a plurality of long sides and short sides. In such a pattern, the change in resistance value on the long side becomes dominant, and the detection axis of each MRE is set along the direction in which the long side is provided.

The sensing axes of the two MREs are set to make an angle of 45 degrees and -45 degrees with respect to the magnetic center of the bias field. Thereby, since the increasing and decreasing directions of the resistance values of the two MREs are different with respect to the change of the direction of the bias magnetic field, the change of the midpoint potential between the two MREs can be increased. The midpoint potential becomes the output of the MRE bridge.

When a plurality of MRE bridges are formed on the substrate 5, the differential output between the midpoint potentials of the MRE bridges is calculated and the differential output is used as the output of the magnetic sensor 1. It This differential output corresponds to the change in the direction of the magnetic field due to the rotation of the rotor 10 by canceling out the error component contained in the midpoint potential of each MRE bridge. Therefore, the rotational position of the rotor 10 can be detected with high accuracy based on the differential output.

In either case where one MRE bridge or a plurality of MRE bridges are formed on the substrate 5, the individual MREs forming each MRE bridge generate a bias magnetic field whose direction changes as the rotor 10 rotates. Therefore, it is necessary to arrange the rotor 10 along the rotation direction of the rotor 10. Thus, the magnetic sensor 1 according to the present embodiment
Has directivity in its detection direction.

This magnetic sensor 1 is formed by injection molding of resin using the above-mentioned bias magnet 3, the substrate 5 on which the detecting portion 4 is formed, the terminal (not shown) connected to the detecting portion 4 and the like as insert parts. The housing 2 is formed. The housing 2 has a flange 6 for attaching the magnetic sensor to another member (for example, a vehicle body). A through hole 6a is formed in the flange 6,
The magnetic sensor 1 is fixed by inserting a bolt or the like into the through hole 6a.

Here, when the rotation detecting device composed of the magnetic sensor 1 and the rotor 10 configured as described above is mounted in the vicinity of the internal combustion engine in order to detect the rotational speed of the internal combustion engine of the vehicle, its object When the vehicle type changes, the location for attaching the magnetic sensor 1 also changes, so the shape of the flange 6 for fixing the magnetic sensor 1 and the angle of the flange 6 must be changed. Further, when the rotation detection device of the present embodiment tries to detect the rotation speed of each wheel of the vehicle, the same problem as described above occurs.

Therefore, in the present embodiment, with respect to the resin injection mold for molding the housing 2 of the magnetic sensor 1, the mold for molding the flange 6 for fixing the magnetic sensor 1 is a nested mold. It is possible to accommodate variations in the shape and mounting angle of the flange 6. Hereinafter, the structure of the resin injection molding die 20 of the present embodiment will be described with reference to FIG.

FIG. 2 shows a schematic structure of an injection molding die for molding the housing 2 of the magnetic sensor 1. In FIG. 2, the injection molding die 20 includes a fixed die 11 and a movable die 12 that is movable relative to the fixed die 11. The fixed mold 11 and the movable mold 12 each have a groove portion 1 into which a nesting mold 13 is fitted.
5, 16 are formed.

FIG. 3 shows the appearance of the nesting die 13. As shown in FIG. 3, the nesting die 13 is formed in a substantially circular shape as a whole, and a space corresponding to the shape of the flange 6 is provided inside thereof. Further, on the outer periphery of the insert mold 13, a knock pin 1 for preventing movement in the rotation direction is provided.
3a is formed. Corresponding to the knock pins 13a of the insert mold 13, recesses (not shown) that engage with the knock pins 13a are formed at a plurality of locations on the bottom surface of the groove 15 of the fixed mold 11. Therefore, by appropriately selecting the recess that engages with the knock pin 13a of the insert mold 13,
The nesting die 13 can be held between the fixed die 11 and the movable die 12 at a position rotated by an arbitrary angle. Thereby, the mounting angle of the flange 6 formed by the nesting mold 13 to the housing 2 can be arbitrarily changed.

As a matter of course, the position and the number of recesses formed on the bottom surface of the groove 15 of the fixed mold 11 are determined according to the variation of the mounting angle of the flange 6 with respect to the housing 2.

A procedure for molding the housing 2 and the flange 6 of the magnetic sensor 1 using the above injection molding die will be described.

First, of the plurality of recesses formed in the bottom of the groove 15 of the fixed mold 11, the knock pin 13a is inserted into a desired recess.
The nesting mold 13 is assembled to the fixed mold 11 so that they engage with each other. Next, the bias magnet 3, the substrate 5 on which the detector 4 is formed, and the terminal (not shown) connected to the detector 4
The insert parts consisting of etc. are fixed mold 11 and movable mold 12
It is placed in the space formed between and. Although not shown, a slide core that is moved by the mold closing operation of the movable mold 12 is provided between the fixed mold 11 and the movable mold 12, and the fixed core 11 and the movable mold 12 are moved by this slide core.
The insert parts are held in place at the same time when the molds are closed.

Then, the molten resin is injected into the space between the fixed die 11 and the movable die 12 with the insert part held at a predetermined position. By cooling and solidifying the melted resin, the resin housing 2 including the insert part is formed. A flange 6 is integrally formed at a predetermined position of the resin housing 2 by a nesting die 13 at a predetermined mounting angle.

After the resin is solidified, the movable die 12 is opened. Then, the push pin 14 allows the housing 2
And by pressing the nesting die 13, the magnetic sensor 1
Is pushed out from the fixed mold 11 together with the nesting mold 13. After that, the magnetic sensor 1 is removed from the insert mold 13.
Thus, the magnetic sensor 1 which is a resin product
At the same time, the magnetic sensor 1 is easily pushed out from the fixed mold 11 by using the nesting mold 13 by pushing it out from the fixed mold 11.
Can be taken from.

As described above, according to the injection molding die of this embodiment, since the flange 6 for fixing the magnetic sensor 1 to another member is formed by the nesting die 13, the fixed die 11 is formed. The attachment angle of the flange 6 can be freely changed only by changing the attachment angle to the. Therefore, since it is not necessary to change the mold 20 including the fixed mold 11 and the movable mold 12, it is possible to use a common mold even when the mounting angle of the flange 6 varies.

Further, when it is necessary to change not only the mounting angle but also the shape of the flange 6, a separate nesting mold in which the shape of the inner space is changed is prepared. The housing 2 and the flange 6 of the magnetic sensor 1 are molded using different nesting molds. Even in this case, since the fixed mold 11 and the movable mold 12 can be used in common, the mold cost can be reduced.

In the present embodiment, the housing 6 of the magnetic sensor 1 having the detecting portion 4 formed of the MRE bridge is exemplified as the resin product molded by the injection molding die. As described above, the magnetic sensor 1 including the detection unit 4 including the MRE bridge has directivity in the detection direction. Therefore, the angle of the housing 2 in which the detection unit 4 is insert-molded cannot be changed arbitrarily. However, if the mounting angle and shape of the flange 6 that is the fixed portion of the magnetic sensor 1 can be changed,
Since the main body portion of the magnetic sensor 1 except for the flange 6 can be made common, the significance of using the above-mentioned injection molding die is great.

(Other Embodiments) In the above-described embodiment, the knock pin 13a is formed on the outer periphery of the insert mold 13 as the engaging portion of the insert mold 13. However, the shape of the engaging portion is not limited to the knock pin 13a, and for example, as shown in FIG.
It is also possible to form a polygonal shape such as a square shape and use the outer shape itself as the engaging portion. In this case, the bottom shapes of the groove portions 15 and 16 of the fixed die 11 and the movable die 12 are also formed in a polygonal shape similar to the outer shape of the nesting die 23.

In the above-mentioned embodiment, the fixed mold 11 is used.
Although the example in which the recessed portion that engages with the knock pin 13a is provided in the bottom portion of the groove portion 15 is described, the recessed portion that engages with the knock pin 13a is provided in the bottom portion of the groove portion 16 of the movable die 12 according to the change range of the attachment angle of the flange 6. May be provided.

Further, in the above-described embodiment, the magnetic sensor housing is exemplified as the resin product molded by the injection molding die, but the invention is not limited to this.
It can be widely applied to resin products having a fixing portion.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram schematically showing a configuration of a rotation detection device including a rotor and a magnetic sensor molded by an injection molding die according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a structure of an injection molding die.

FIG. 3 is a view showing a nested shape.

FIG. 4 is a diagram showing a shape of a modification of the nest type.

[Explanation of symbols]

1 Magnetic sensor 2 Housing (resin product) 10 rotor 11 fixed type 12 movable 13 Nested 14 Extruded pin 20 Mold for injection molding

Claims (4)

[Claims] 1. A space formed inside both molds, comprising a fixed mold and a movable mold movable relative to the fixed mold, with the fixed mold and the movable mold closed. In an injection molding die for injecting a molten resin into a resin product having a predetermined shape, a fixing portion for fixing the resin product to another member is formed on the resin product. The mold for injection molding, wherein a mold for forming the part is a nested mold that can be attached to and taken out from the internal space of the fixed mold and the movable mold. 2. An engaging portion that engages with at least one of the fixed die and the movable die is formed on an outer periphery of the nesting die,
2. The injection according to claim 1, wherein at least one of the fixed die and the movable die has a plurality of engagement positions with respect to the engagement portion of the nesting die set in the rotation direction of the nesting die. Mold for molding. 3. The fixed die is provided with an extruding pin for extruding the resin product, and the extruding pin fixes the resin product and the nest die integrally by pressing the nest die. The mold for injection molding according to claim 1 or 2, which is extruded from the mold. 4. The injection mold according to claim 1, wherein the resin product is insert-molded with a detection portion having directivity in a detection direction.