JP2001141738A - Rotation sensor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation sensor resistant to vibration and dust and having high detection precision at a low cost. SOLUTION: In this rotation sensor 10, a rotation detecting element 12 and electronic parts 13 for controlling it are provided on a lead frame 11, a permanent magnet 14 is provided opposite to the rotation detecting element 12, these parts are sealed in a case 16, and a lead wire 14 is guided from the outside of the case to the lead frame 11 and connected thereto. The electronic part 13 is covered with silicon 17, and the case 16 is formed of an integral molding with the lead frame 11 and the like inserted therein. The mold coating 16 firmly supports the insert parts with high sealing degree, and is resistant to vibration and dust. Even if the electronic parts 13 are thermally expanded, the silicon layer (cushioning material) 17 absorbs the expansion by the elastic force to prevent the damage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation sensor used as a wheel speed sensor and the like and a method of manufacturing the same.

[0002]

2. Description of the Related Art As a rotation sensor for detecting wheel speed, Japanese Patent Application Laid-Open No. 5-500710 discloses a rotation sensor in which a coil is used as a rotation detecting element and the coil is coated with a resin (coated with resin). . The mold coating is
This is for protecting the rotation detecting element from vibration and dust intrusion. This is because such a sensor is mounted on a vehicle wheel or the like and is exposed to severe vibration and dust.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. 7-198736, a rotation detecting element such as a Hall IC and its control are disclosed in Japanese Patent Application Laid-Open No. Hei 7-198736. A rotation sensor has been developed in which electronic components are provided and the lead frame is enclosed in a case.

[0004]

The above-mentioned conventional Hall IC
In a rotation sensor including a rotation detection element such as the above, dust intrusion into the case is sealed by resin welding of an opening, O-ring fitting, etc., and the effect is not sufficient.
It does not have sufficient durability against vibration.

In the manufacturing method, a base in which a part of a lead frame is inserted is formed, and a rotation detecting element and a control electronic component are mounted on the lead frame. Manufactured in sealed storage. The method involves a large number of steps and causes an increase in cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotation sensor comprising a rotation detecting element such as a Hall IC and the like, in which a firm sealing of the rotation detecting element and the like is obtained and the cost is reduced.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to insert a control electronic component and to integrally mold a case. The integral molding has a high sealing degree and is resistant to vibration and dust.

Next, the electronic component thermally expands due to self-radiation or the like. At this time, if the mold coating cannot absorb the expansion such as deformation following the thermal expansion, the electronic component may be damaged. In addition, there is some adverse effect such as the interface between the electronic component and the coating coming off and being flooded. For this reason, molding was performed using an elastic resin capable of absorbing the thermal expansion.

[0009]

As an embodiment of the present invention, a lead frame is provided with a rotation detecting element and an electronic component for controlling the rotation detecting element, and a permanent magnet is provided opposite the rotation detecting element. A rotation sensor in which a rotation detecting element, a control electronic component, and a permanent magnet are hermetically sealed in a case, and a lead wire is guided from the outside of the case and connected to the lead frame, wherein the lead frame, the rotation detecting element The case is formed by integral molding in which the control electronic component, the permanent magnet and the lead wire connection portion are inserted, and the molding resin has elasticity that does not hinder the thermal expansion of the control electronic component and the molding resin itself. A configuration made of resin is adopted.

[0010] The rotation sensor having this configuration is preferably used in an environment that is not exposed to stepping stones or the like, such as a wheel speed sensor built in a hub bearing. This is because the elastic resin generally has poor durability under an environment such as a stepping stone. In a rotation sensor used in such an environment, the elastic resin is only the coating of the control electronic component, and the other molding resin, that is, the resin that covers the coating and forms the case is less than the elastic resin. It has a large longitudinal elastic modulus, is hard, and is resistant to impacts such as stepping stones. With this configuration, the control electronic component is protected by the thermal expansion absorbed by the partial elastic resin coating layer.

Here, a general resin has a longitudinal elastic modulus of 500 kgf / mm ² and is divided into a hard resin and a soft resin. In the thermal expansion and contraction, the former has a width twice or more as large as the latter. Expand and contract. For this reason,
The elastic resin has a longitudinal elastic modulus of 500 kgf / mm ^2.
The following should be used.

In one embodiment of the former method of manufacturing a rotation sensor, the rotation detecting element and its control electronic components are mounted on the lead frame connected in parallel to a carrier band, and then each lead frame is mounted. A structure is employed in which the lead wires are connected by cutting off a gap between the leads, and thereafter, each lead frame is integrally molded with the control electronic component and an elastic resin which does not hinder thermal expansion of itself.

In manufacturing the latter rotation sensor, in the above-described manufacturing method, the control electronic component is coated with an elastic resin before separating each lead frame, and the lead frame is separated. Is covered with a resin having a greater longitudinal elastic modulus than the elastic resin, and is integrally molded.

In these manufacturing methods, the connection between the lead frames may be cut after connecting the lead wires, or after the integral molding.

The rotation detecting element is preferably a Hall IC, but may be a Hall element, a semiconductor magnetoresistive element, a ferromagnetic magnetoresistive element, or a magnetic sensor element such as a proton magnetometer. In addition, the elastic resin has elasticity that does not hinder the thermal expansion of electronic components such as silicon and polyamide-based hot melt resin. The hard resin includes nylon resin containing glass fiber and epoxy resin. Use a shock-resistant material as appropriate.

[0016]

1 and 2 show an embodiment. In this embodiment, a lead frame 11 is provided with a Hall IC 12 and electronic components 13 such as a control resistor and a capacitor, and the electronic component 13 is formed of silicon (buffer). Material 17). A lead wire 14 made of a harness is connected to the base of the lead frame 11, and a permanent magnet 15 is provided at the tip. These components (such as the Hall IC 12) are covered with a mold 16 by nylon or epoxy.
In the figure, reference numeral 18 denotes a vehicle body mounting bracket integrally formed at the time of mold coating.

The rotation sensor 10 is installed so as to face a pulsar ring (a ring such as a peripheral gear surface or a magnetic force surface of a peripheral SN pole), and the rotation of the pulsar ring causes a magnetic line of force emitted from the magnet 15 to fluctuate. IC1
2 to detect the rotation speed. For example, the pulsaring is attached to the axle of an automobile to detect the wheel speed.

Next, a method of manufacturing the rotation sensor 10 will be described with reference to FIG. 3. First, as shown in FIG. 3A, a lead frame 11 connected in parallel to a carrier band 20 from a hoop material. Then, the Hall IC 12 and its control electronic component 13 are mounted on each lead frame 11 by soldering (FIGS. 2B and 2C). Either of the mounting order of the Hall IC 12 and the electronic component 13 may be performed. Next, a buffer layer 17 is formed and coated on the electronic component 13 by applying silicon (FIG. 4D). Thereafter, the carrier band 20 (connection portion of each lead frame 11) is cut off, and each lead frame is cut. 11 is separated ((e) in the figure). The buffer layer 17 is a Hall element 12
Can also be formed (covered) around.

After connecting the lead wires 14 to the respective lead frames 11 with the electronic components by soldering (FIG. 3 (f)), a permanent magnet is positioned at the tip of the lead frame 11, and it is placed in a glass fiber-filled nylon. Depending on the resin and the epoxy resin, for example, 400 to 800 kgf / cm
^The mold is coated with a molding pressure of ² , and the case 16 is integrally molded ((g) in the figure). At this time, the electronic component 13 is protected from the molding pressure by the buffer layer 17. Lead wire 1
4 is connected after the carrier band 20 is cut because the lead wire 14 is in the way when the carrier band 20 is cut.

In this embodiment, the shock-resistant material is used. However, if the shock-resistant material is not required, the application of the cushioning material 17 shown in FIG. 17 by using a silicone or polyamide hot melt resin at a molding pressure of, for example, 20 kgf / cm ² or less, preferably 10 kgf / cm ² or less.
6, the rotation sensor 10 integrally molded with the elastic resin 16 is obtained as shown in FIG.

In the manufacture thereof, the connection of the lead wire 14 to the lead frame 11 is not limited to after the carrier band 20 is cut off, but if the lead wire 14 does not hinder the connection (FIG. 9 (c) or (d)). ) May be connected after). Also, as shown in FIGS. 5A and 5B or FIGS. 8A and 8B, the connection of the lead wires 14, the buffer layer 17, and the case 16
After molding, the lead frame 11 may be separated. At this time, as shown in FIGS. 6 and 7, the rotation sensor 10
1a is exposed. Since the lead frames 11 shown in FIGS. 8A and 8B are not continuous, each lead frame 11 is positioned at the time of molding the case 16 by sandwiching each tie bar 11b. Further, the lead frame 11 shown in FIGS. 3 (a), 5 (a) and 8 (a)
Instead of press stamping from a hoop material, it can also be obtained by stamping from a flat plate.

Various embodiments of the rotation sensor 10, such as those shown in FIGS.

[0023]

As described above, according to the present invention, since the case is formed by integral molding with electronic components and the like inserted therein, a rotation sensor that is resistant to severe vibration and dust can be obtained, and the cost can be reduced. It can be.

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment.

FIG. 2A is a cutaway plan view of the embodiment, and FIG. 2B is a cutaway front view of the same embodiment.

FIG. 3 (a) is a production drawing of the same embodiment.

FIG. 3 (b) is a view showing the production of the embodiment.

FIG. 3 (c) is a drawing of the same embodiment.

FIG. 3 (d) is a drawing of the same embodiment.

FIG. 3 (e) is a view showing the production of the embodiment.

FIG. 3 (f) is a drawing of the same embodiment.

FIG. 3 (g) is a production drawing of the same embodiment.

FIG. 4 (a) is a cutaway plan view of another embodiment, and FIG. 4 (b) is a cutaway front view thereof.

FIG. 5 (a) is a drawing of another embodiment.

FIG. 5 (b) is a view showing the production of the embodiment.

FIG. 6 is a perspective view of the embodiment.

FIG. 7A is a cutaway plan view of the embodiment, and FIG. 7B is a cutaway front view of the same embodiment.

FIG. 8 (a) is a production drawing of another embodiment.

FIG. 8 (b) is a view showing the production of the embodiment.

9A and 9B show another embodiment, in which FIG. 9A is a perspective view, and FIG.

FIG. 10 is a fragmentary front view of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rotation sensor 11 Lead frame 12 Hall IC (rotation detection element) 13 Electronic component 14 Lead wire 15 Permanent magnet 16 Molding case 17 Silicon (buffer material) 20 Carrier band

Claims (6)

[Claims] A rotation detecting element provided on a lead frame;
And a control electronic component 13 thereof, and a permanent magnet 15 is provided so as to face the rotation detecting element 12, and the lead frame 11, the rotation detecting element 12,
The rotation sensor 10 in which a control electronic component 13 and a permanent magnet 15 are hermetically sealed in a case 16, and a lead wire 14 is guided from the outside of the case 16 to the lead frame 11 and connected thereto. , The rotation detecting element 12, the control electronic component 13, the permanent magnet 15, and the connecting portion of the lead wire 14 are inserted into the case 16 by integral molding.
Is formed, and the molding resin is used as the control electronic component 1.
3. A rotation sensor characterized by being made of an elastic resin which does not interfere with thermal expansion of the mold resin itself. 2. The resin according to claim 1, wherein the elastic resin is only the coating of the control electronic component, and the resin forming the case around the coating is made of a resin having a larger longitudinal elastic coefficient than the elastic resin. The rotation sensor according to claim 1. 3. An elastic resin having a longitudinal elastic coefficient of 500.
The rotation sensor according to claim 1, wherein the rotation sensor is equal to or less than kgf / mm ² . 4. A method for manufacturing a rotation sensor according to claim 1, wherein the rotation detecting element is connected to the lead frame connected in parallel to a carrier band.
2 and the control electronic component 13 are mounted, and a connection between the lead frames 11 is cut off to remove the lead wires 14.
After that, each lead frame 11 was integrally molded with the control electronic component 13 and an elastic resin which would not hinder the thermal expansion of itself, or the electronic component 13 was coated with the elastic resin 17. Thereafter, the periphery of the coating is covered with a resin 16 having a larger longitudinal elastic coefficient than the elastic resin 17, and is integrally molded to form a rotation sensor. 5. The lead frame according to claim 4,
A method for manufacturing a rotation sensor, comprising connecting the lead wire (14) before cutting off a joint between the two. 6. The method for manufacturing a rotation sensor according to claim 5, wherein the joint between the lead frames is cut after the integral molding.