JPH07198736A - Rotation sensor and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a rotation sensor which enables low-speed rotation detection of a magnetic rotating body and has high manufacturing and structural reliability. A magnet 25 and a magnetoelectric conversion element 22 are used as means for measuring the frequency of the magnetic rotating body 100, and a terminal 24 having these elements installed at the tip thereof is used as a base 2
3 is integrally insert-molded with the above-mentioned terminal 2
4 is exposed on the surface of the base 23 to form the surface mounting electrode portion 24a, and the electronic component 2 is formed on the electrode portion 24a.
Implemented 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation sensor for detecting the rotation speed of, for example, a gear-shaped magnetic rotating body, and a manufacturing method thereof.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view showing a conventional rotation sensor. In the rotation sensor shown in FIG. 7, a coil 2 is wound around a magnetic iron core 4 via a bobbin 3, and the outer circumference of the coil 2 is covered with a resin-molded case 1. The tip of the magnetic iron core 4 has a gear-shaped magnetic rotating body 10
Biasing magnets 5 and magnetic flux converging spacers 6 are installed at the other end of the magnetic iron core 4, and are positioned by a rubber grommet 7. The lead wire (not shown) of the coil 2 is connected to the terminal 8, which is connected to the lead wire 10 and the connector 1.
It is connected to an external circuit via 2. Incidentally, 9 is a cover for covering the rear end of the rotation sensor, and 11 is an O-ring for keeping airtightness inside the rotation sensor.

FIG. 8 is a block circuit diagram of a conventional rotation sensor, and 14 is the rotation sensor described with reference to FIG.
5 is a filter circuit for noise attenuation, 16 is a Schmitt trigger circuit composed of a comparator and a switching element,
Reference numeral 17 is a computer unit (ECU).

Next, the operation of the above apparatus will be described.
In the conventional rotation sensor 14, as shown in FIG. 7, the magnetic iron core 4 and the spacer 6 are provided close to each other on both end surfaces of the bias magnet 5.
Since the coil 2 is wound around the magnetic core 4, the lead 10 connected to the external circuit is rotated by the rotation of the gear-shaped magnetic rotating body 100 that is close to the tip of the magnetic core 4.
The AC voltage excited in the coil 2 is output. This AC voltage output has its noise attenuated by the filter circuit 15 shown in FIG. 8, and is converted into a pulse wave by the Schmitt trigger circuit 16. And the computer unit 17
Calculates the number of rotations of the gear-shaped magnetic rotating body 100 by periodically measuring the pulse wave.

[0005]

Since the conventional rotation sensor and its system are constructed as described above, it is difficult to detect the rotation when the gear-shaped magnetic rotating body 100 to be detected is rotating at a low speed. There was a problem. That is,
By "the electromotive force induced in the magnetic circuit is equal to the rate of temporal decrease in the number of magnetic flux linkages in this circuit"(Faraday's law), the rotation sensor of the gear-shaped magnetic rotor 100 becomes slow, and the rotation sensor The output of
As a result, when the rotating body rotates at a low speed, the S / N ratio of the output of the rotation sensor and the noise becomes small, and the rotation detection accuracy deteriorates. Further, when the output current of the rotation sensor becomes a current value in a minute region, for example, 1 mA or less, there is a problem that the contact resistance of the terminal fitting portion of the connector increases.

The present invention has been made to solve the above-mentioned problems, and the output voltage level does not depend on the rotational speed of the gear-shaped magnetic rotating body to be detected,
Predetermined H level and L level are maintained so that low speed rotation can be detected. Another object of the present invention is to provide a rotation sensor which is simple and highly reliable both in terms of structure and manufacturing.

[0007]

According to a first aspect of the present invention, there is provided a magnetoelectric conversion means for performing switching operation in both high and low states based on a predetermined hysteresis due to a change in magnetic flux generated by rotation of a magnetic rotating body. A connector for outputting a signal corresponding to the rotation speed of the magnetic rotating body from the magnetoelectric conversion means, and a terminal for electrically connecting the magnetoelectric conversion means and the connector are provided.
According to a second aspect of the present invention, the terminal is insert-molded on a resin base, a part of the terminal is exposed on a surface of the base, and at least a part of the exposed part of the terminal is used as a surface mounting electrode portion. An electronic component is mounted on the surface mounting electrode portion. According to a third aspect of the present invention, the surface mounting electrode portion for mounting the electronic component is formed by bending the terminal into a double structure.

A method of manufacturing a rotation sensor according to claim 4 is
The process of punching the terminal into a predetermined shape and the electrode part which is at least the electronic component mounting part of this terminal
A step of bending to form a heavy structure, a step of insert-molding this terminal into a resin base so that at least the electrode portion is exposed, a step of attaching a magnetoelectric conversion means to the tip of this terminal, And a step of mounting an electronic component on the electrode portion.
In the invention according to claim 5, when molding the base, a groove is formed in a part of a portion corresponding to an exposed portion of the terminal, and after the terminal is insert-molded into the base, the terminal is not necessary via the groove. It is provided with a step of cutting out a portion.

[0009]

According to the invention of claim 1, the magnetoelectric converting means of the rotation sensor is an IC having a magnetoelectric converting element such as a Hall element or a magnetoresistive element, and a permanent magnet close to the IC. The switching operation between the H and L states is performed based on a predetermined hysteresis due to the change in the electric current. Therefore, the electric signal output thereof does not depend on the rotational speed of the magnetic rotating body that is the detection target. Therefore, even if the rotating body to be detected is rotating at low speed, the rotation can be detected. Also, the reliability of the connector terminal fitting portion is improved. According to the invention of claim 2, the terminal is integrally insert-molded on the resin base, so that the manufacturing process is simplified and the automated production is promoted. In addition, since at least the portion of the terminal other than the electronic component mounting surface is buried in the base, most of the terminal is protected from the outside, and the durability as a product is improved. Furthermore, the surface of the terminal on which the electronic components are mounted is not covered by the base and serves as a surface mounting electrode, while the surrounding base functions as a resist, allowing reflow soldering, facilitating automated production, and good performance. Surface mounting becomes possible. Further, according to the invention of claim 3, since the bent portion of the terminal absorbs the stress to the soldering portion due to the heat shrinkage of the base material,
Improves reliability. According to the invention of claim 4, the step of punching the terminal into a predetermined shape, the step of bending at least the electrode portion of the terminal where the electronic parts are mounted to have a double structure, and the step of exposing the terminal at least the electrode portion are exposed. The method according to any one of claims 1 to 3, wherein a step of insert-molding into a resin base so as to be in a state, a step of attaching a magnetoelectric conversion means to a tip portion of the terminal, and a step of mounting an electronic component on the electrode portion are performed.
It is possible to manufacture a rotation sensor that achieves the above function. In the invention of claim 5, the connecting portion between the terminals, which is necessary for insert-molding the terminal on the base, can be cut through the groove portion for the hole. Further, since the surface mounting electronic component is mounted on the front side portion of the groove, reflow soldering becomes easy.

[0010]

【Example】

Example 1. Hereinafter, a rotation sensor according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view showing a rotation sensor according to this embodiment, FIG. 2 is a rear view of a base during a manufacturing process, and FIG. 3A is a plan view of the base during the manufacturing process. In the figure, the terminal 24 is a resin base 23.
Is insert-molded (when the base 23 is resin-molded, the terminal 24 is installed in the resin when the resin is cured), and most of it is covered. A permanent magnet 25, which is also insert-molded on the base 23, is installed at the tip of the terminal 24,
The magnetoelectric conversion element 22 is provided in the vicinity of the permanent magnet 25,
The gear-shaped magnetic rotating body 100 is arranged so as to face the permanent magnet 25 and the magnetoelectric conversion element 22. A surface mounting electrode portion 24a formed by bending the terminal 24 is exposed at a predetermined position on the surface of the base 23, and a surface mounting electronic component 26 such as a capacitor is mounted on the mounting electrode portion 24a. . That is, the terminal 24
Is the mounting electrode 24a and the magnetoelectric conversion element land portion 24.
It is insert-molded on the base 23 so that only c and the connector terminal fitting portion 24b are exposed. Further, the case 21 is fixed to the outer portion of the base 23, and the base 2
An O-ring 28 is installed at the fitting portion between the case 3 and the case 21. Further, the rear end portion 21a of the case 21 is subjected to heat staking, and the heat staking portion is filled with resin 29.

FIG. 5 is an enlarged cross-sectional view showing the tip of the base 23 to which the magnetoelectric conversion element 22 is attached. The magnetoelectric conversion element 22 is insert-molded into the base 23 to form the permanent magnet 2.
5 is attached via RTV rubber 27. The RTV rubber 27 plays a role of minimizing shake of the magnetoelectric conversion element 22 due to external vibration due to its elastic force.
Further, the lead 22 a of the magnetoelectric conversion element 22 is connected to the land portion of the terminal 24 integrally formed with the base 23.

FIG. 6 shows a Hall IC as the magnetoelectric conversion element 22.
FIG. 3 shows an example of a circuit using the above, in which the variation frequency of the magnetic field generated by the rotation of the gear-shaped magnetic rotating body 100 is detected as a change in voltage by the hall element 200, and the change in voltage generated in the hall element 200 is differentiated. It is amplified by the amplifier 201 and converted into a pulse wave by the Schmitt trigger circuit 202. Then, it is sent to an external computer unit (not shown) through the lead 22a, the terminal 24, the surface-mounting electronic component 26 for noise removal, and the connector, and the rotation speed is detected. A magnetoresistive element or the like may be used as the magnetoelectric conversion element 22.

Next, the rotation detecting operation by the rotation sensor will be described. The magnetoelectric conversion element 22 is a Hall element or a magnetoresistive element (MR) having a Schmitt trigger circuit built-in.
Since the switching operation between the H and L states is performed based on the predetermined hysteresis due to the change in the magnetic flux, the frequency of the rotation speed of the gear-shaped magnetic rotating body 100 which is the detection target can be detected, and the magnitude of the detection output. Does not depend on the rotation speed. Therefore, compared to the conventional device (see FIGS. 7 and 8), the SN
The ratio is improved, noise is reduced, and low-speed rotation detection of the detection target becomes possible. Also, the reliability of the connector terminal fitting portion is improved.

Further, according to this embodiment, the resin base 2
Since the terminal 24, the permanent magnet 25, and the like are integrally insert-molded in 3, the manufacturing process is simplified and the automated production is promoted. Further, since the surface of the terminal 24 excluding the electronic component mounting surface, the magnetoelectric conversion element land and the connector terminal fitting portion is embedded in the base, most of the terminal 24 is protected and the durability as a product is enhanced. Further, by providing the O-ring 28 in the fitting portion between the base 23 and the case 21, it is possible to ensure the airtightness inside the rotation sensor. Further, since the base 23 is inserted to the tip of the case 21 and the end portion of the case 21 is heat-crimped and the heat-crimped portion is covered with the resin 29, it is possible to prevent moisture from entering the inside of the sensor.

Next, a method of manufacturing the rotation sensor will be described. First, the terminal 24 is punched into a predetermined shape from the wound brass strip hoop material by pressing.
4 (a) is a side view showing the terminal 24 punched into a predetermined shape, FIG. 4 (b) is a plan view thereof, and FIG. 4 (c) is FIG. 4 (b).
6 is a cross-sectional view taken along the line CC of FIG. Then, as shown in FIG.
Electrode part 24, which is the electronic component mounting part of terminal 24
A and the connector terminal fitting portion 24b are bent into a predetermined shape and pressed to have a double structure. Further, the land portion 24c for the magnetoelectric conversion element at the tip of the terminal 24 is punched out by the thickness corresponding to the plate thickness.

The terminal 24 processed as described above is
It is integrally insert-molded by the resin-molded base 23. Then, as shown in the rear view of the base of FIG. 2, a predetermined unnecessary connecting portion 30 of the terminal 24 is cut by press working. The terminal cutting portion of the base 23 has a groove shape 31 when viewed from the back side so that a die for press working can be easily set.

FIG. 3A is a plan view of the base 23 during the manufacturing process similarly to FIG. 2, and FIG. 3B is an enlarged view of a portion A of FIG. 3A.
FIG. 3C is a sectional view taken along the line BB of FIG.
The surface-mounting electrode 24a of the terminal 24 insert-molded in 3 serves as a mounting land portion of the surface-mounting electronic component 26 without being covered by the base 23. That is, FIG.
As shown in (c), the terminal 24 is bent to have a thickness (2t) that is twice the terminal plate thickness (t), and that portion is not covered by the base 23 and is formed on the base surface. Exposed.

Next, the leads of the magnetoelectric conversion element 22 are connected to the land portion 24c provided at the tip of the terminal 24, and the surface mounting electronic parts 26 such as capacitors and resistors are mounted on the surface mounting electrodes 24a. , Reflow soldering both.

Finally, the O-ring 28 is mounted in the O-ring groove of the base 23, the base 23 is inserted to the tip of the case 21, the case end 21a is heat-staking, and the heat-staking portion is covered with resin. To do so.

As described above, the terminal 24 is not covered by the base 23 at its electronic component mounting portion and serves as the surface mounting electrode 24a. On the other hand, the peripheral base 23 functions as a resist, so that reflow soldering is performed. Is possible,
Automated production is promoted and good surface mounting becomes possible. In addition, a connecting portion between the terminals, which is necessary for insert-molding the terminal 24 into the base 23, is cut after the insert-molding through the groove 31 provided in the base 23, and the surface-mounting electronic component 26 is cut in that portion. As a result, the reflow soldering is facilitated by utilizing the groove 31. Further, since the bent portion of the terminal 24 absorbs the stress to the soldered portion due to the heat shrinkage of the base material, the stress is dispersed during the manufacturing process, and the reliability as a product is improved.

[0021]

As described above, according to the invention of claim 1,
Since the IC having a built-in magnetoelectric conversion element such as a Hall element and the permanent magnet close to the IC are used as the magnetoelectric conversion means, the rotational speed can be detected even when the rotating body to be detected is rotating at a low speed, resulting in higher accuracy. Higher detection is possible.
Also, the reliability of the connector terminal fitting portion is improved. Also,
According to the invention of claim 2, since the terminal and the magnetoelectric conversion means are integrally insert-molded on the resin base, the manufacturing process is simplified and the automated production is promoted. In addition, since the portion of the terminal other than the electronic component mounting surface is buried in the base, it is protected from the outside and the durability as a product is enhanced. Further, according to the invention of claim 4, a step of punching the terminal into a predetermined shape, a step of bending at least an electrode portion, which is an electronic component mounting portion, of the terminal so as to have a double structure, and a step of bending the terminal at least the electrode. The method according to claim 1, wherein a step of insert molding into a resin base so that the portion is exposed, a step of attaching a magnetoelectric conversion means to the tip of this terminal, and a step of mounting an electronic component on the electrode portion are performed. 1, 2 and 3 rotation sensors can be manufactured. Further, in the mounting work of the electronic parts of the terminal, reflow soldering becomes possible, automation production is promoted, and good surface mounting becomes possible. Further, according to the invention of claim 5, since the bent portion of the terminal absorbs the stress to the soldering portion due to the heat shrinkage of the base material, the reliability is improved. Further, a connecting portion between the terminals, which is necessary for insert-molding the terminals into the base, can be cut through the groove portion for the hole. Further, since the surface mounting electronic component is mounted by utilizing the groove provided on the base, reflow soldering becomes easy.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a rotation sensor according to an embodiment of the present invention.

FIG. 2 is a bottom view showing the base during the manufacturing process of the rotation sensor according to the embodiment.

FIG. 3 is a plan view, a partial enlarged view, and a partial cross-sectional view showing a base of a rotation sensor according to the above embodiment.

FIG. 4 is a side view, a plan view, and a partial cross-sectional view showing a terminal of the rotation sensor according to the above embodiment.

FIG. 5 is an enlarged cross-sectional view showing a tip portion of the base of the rotation sensor of the above embodiment.

FIG. 6 is a circuit diagram showing a magnetoelectric conversion element of the rotation sensor of the above embodiment.

FIG. 7 is a side sectional view showing a conventional rotation sensor.

FIG. 8 is a block circuit diagram of a conventional rotation sensor.

[Explanation of symbols]

 21 Case 22 Magnetoelectric Conversion Element 23 Base 24 Terminal 24a Surface Mounting Electrode 25 Permanent Magnet 26 Surface Mounting Electronic Component 27 RTV Rubber 28 O Ring 29 Resin 31 Groove 100 Gear Magnetic Rotating Body

Claims (5)

[Claims] 1. A magnetoelectric conversion means for performing switching operation in both high and low states based on a predetermined hysteresis due to a change in magnetic flux generated by the rotation of the magnetic rotation body, and a rotation speed of the magnetic rotation body from the magnetoelectric conversion means. A rotation sensor comprising: a connector that outputs a corresponding signal; and a terminal that electrically connects the magnetoelectric conversion means and the connector. 2. The terminal according to claim 1, wherein the terminal is insert-molded on a resin base, a part of the terminal is exposed on a surface of the base, and at least a part of the exposed part of the terminal is a surface mounting electrode part. The rotation sensor according to claim 1, wherein an electronic component is mounted on the surface mounting electrode portion. 3. The rotation sensor according to claim 2, wherein the surface-mounting electrode portion for mounting the electronic component is formed by bending a terminal into a double structure. 4. A step of punching a terminal into a predetermined shape, a step of bending at least an electrode portion, which is an electronic component mounting portion of the terminal, so as to have a double structure, and a state of exposing at least the electrode portion of the terminal. A manufacturing process of a rotation sensor, comprising: a step of insert-molding into a resin base so as to form, a step of attaching a magnetoelectric conversion means to a tip portion of this terminal, and a step of mounting an electronic component on the electrode portion. Method. 5. The method according to claim 3, wherein when forming the base, a groove is formed in a part of a portion corresponding to an exposed portion of the terminal, and after the terminal is insert-molded into the base,
A method of manufacturing a rotation sensor, which comprises a step of cutting an unnecessary portion of a terminal through the groove.