JPH0620963Y2 - Non-contact angle sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an angle sensor using a non-contact variable resistor using a magnetoresistive element.

[Conventional technology]

A contactless variable resistor having a structure in which a contact is made by interposing a magnetoresistive element and combining a permanent magnet and a yoke is known. It is also known to use a rotary variable resistor as an angle sensor that rotates a magnet or a yoke to change a magnetic field.

For example, the conventional non-contact type rotary variable resistor shown in FIG. 5 is of this kind.

In this conventional variable resistor, an input shaft A that receives a mechanical input in the form of rotation is supported by a flange body C via bearings B and B '. A substantially pot-shaped case D is attached to the flange body C, and a tip edge portion of the case D is formed into a groove E of the flange body C.
And fix it by caulking at a place not shown. A semi-cylindrical magnet G is adhered to the tip of the input shaft A on the case D side via a magnet base F so that the semicircular upper surface of the magnet G changes its horizontal position by the rotation of the input shaft A. There is. In the case D, a magnetoresistive element H is adhered to the surface of a yoke I embedded in the center of the case D so as to face the magnet G with a constant gap. The input / output terminal K connected to the terminal J of the magnetoresistive element H is fixed by inserting the case D, and the lead wire L connected to the input / output terminal K penetrates the cover M mounted on the case D. Has been pulled out. That is, this variable resistor is a non-contact type rotary variable resistor, and the rotation of the input shaft A causes the magnet G to rotate and gives the magnetic resistance element H a varying magnetic field. That is, the resistance of the magnetoresistive element H is changed by the magnetic field, and the potential difference taken out by the input / output terminal K is changed. In other words, the rotation angle of the input shaft A can be read from the amount of change in the output voltage via the lead wire L.

[Problems to be solved by the device]

However, in order to maintain a narrow gap of, for example, 0.08 mm between the magnet G and the magnetoresistive element H, such a conventional non-contact rotary variable resistor is provided at the tip of the input shaft A. The surface of the supported magnet G is the input shaft A.
It is necessary to prevent the vertical runout from occurring due to the rotation of the shaft, and the constituent parts for mounting the two bearings B and B'holding the input shaft A on the flange body C, the magnet G, the magnet base F, etc. Ensuring machining accuracy and assembly accuracy of parts is an important issue. The same thing can be said for the case D side with many processed parts, and also becomes a problem in the assembly of the flange body C and the case D. That is, in the conventional non-contact type variable resistor, there are many parts that require precision, there are many assembling steps, and there is a problem in terms of manufacturing days and manufacturing cost.

Therefore, the present invention has been made in consideration of such a problem, and the problem is that the mounting is easy and the necessary gap between the magnet and the magnetoresistive element is maintained even after the mounting. The object of the present invention is to obtain a contactless rotary variable resistor, that is, an angle sensor, which has a relatively simple structure that can be easily held constant and is inexpensive and can be mass-produced.

[Means for Solving the Problems]

In order to achieve the above object, the non-contact type angle sensor according to the present invention is attached to the rotor body on the surfaces of two magnetoresistive elements which are connected in series and are stacked on the yoke attached to the case body. A contactless angle sensor that measures the amount of rotation of the rotor body by changing the amount of electricity at the intermediate terminal of the magnetoresistive element as the magnet rotates, the surfaces of the rotating magnets facing each other,
Concentric annular fitting portions are formed on the peripheral portions of the case main body and the rotor main body, and the case main body and the rotor main body are fitted to each other at the annular fitting portion, and end faces thereof are brought into contact with each other to form the magnetoresistive element. The front end of the rotor and the surface of the magnet and a predetermined gap are maintained, and the input side end of the rotor body is formed to be engageable with the external rotation shaft, and one end is fixed to the case body and the other end is fixed. A winding spring fixed to the rotor body urges the rotor body toward the case body and exerts a restoring force to the rotation of the rotor body, and the case body and the rotor body are Each is molded by a plastic mold.

The case body and the rotor body are preferably molded by plastic molding.

[Action]

In the non-contact type angle sensor of the present invention, one end of the spring is aligned and locked to the input side end face of the rotor body, and the end face of the rotor body on which the magnet is mounted and the side of the case body on which the magnetoresistive element is mounted are mounted. The end faces are brought into surface contact with their center positions aligned, and the other end of the spring is fixed to the case body to be assembled into one body. Also, this non-contact type angle sensor can be returned to the initial position by the return force of the spring by engaging the external rotation shaft and releasing it while twisting it to any position in the rotation direction with a hand or a screwdriver. It can be returned in an engaged state in close contact with the external rotation shaft.

In the non-contact type angle sensor described above, a constant current is applied to the magnetoresistive element by the lead wires connected to both ends of the two magnetoresistive elements and connected to the pair of input terminals drawn to the output side of the case body. If the rotor main body is made to flow and rotated by the external rotation shaft, the magnet rotates, and the magnetic field changes according to the rotation, and the resistance of the magnetoresistive element changes. After all, the rotation angle of the rotor body can be determined by extracting the potential difference between the intermediate terminal provided in the middle between the pair of input terminals and one input-side terminal and reading the change. it can. Further, due to the action of the spring, the rotor shaft end that transmits the rotation to the rotor body and the rotor body are always in close contact with each other, so that rattling and vibration do not occur and the coupling with the rotor shaft end is easy.

〔Example〕

 The embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIGS. 1 and 2, the angle sensor 1 of the present invention basically has a rotor portion 2 that receives a mechanical input in the form of rotation.
And the case portion 3 that outputs the mechanical input in the form of voltage,
It comprises a spring part 4 for connecting the rotor part 2 to the case part 3.

The rotor body 5 of the rotor portion 2 is molded by plastic molding and has a substantially cylindrical shape having a partition 5a at an intermediate position inside thereof which is orthogonal to the axial direction. The input side on the left side of the drawing is also shown in FIG. As described above, it has a pair of protrusions 5b projecting from the inner peripheral wall toward the center so that it can receive the external force given in the form of rotation by the shaft 6 shown by an imaginary line having a rectangular cross section. . or,
In the empty chamber, that is, the magnet chamber 7, which is formed on the output side on the right side of the rotor body 5 in the figure, a magnet 8 is adhered to the surface of the partition 5a at its bottom surface at a substantially central portion. The magnet 8 is a semi-cylindrical body in which a cylindrical body concentric with the rotation axis of the rotor body 5 is cut along a plane passing through the center and one side is cut off. It can be rotated around. A flange portion 5c is formed on the output-side end edge portion of the rotor body 5, and an inner surface of the flange portion 5c has a step different from the outer edge portion and has an end surface 5d that forms a smooth annular surface of a certain width. Has been formed. The magnet chamber 7 has a smooth inner peripheral wall 5e that is concentric with the center of rotation of the rotor body 5. Further, a protrusion 5f protruding in a direction parallel to the center of rotation of the rotor body 5 is formed on the outer edge portion of the flange portion 5c. It should be noted that the input side end surface 5g of the rotor body 5 has a spring portion 4 to be described later.
3 locking projections 5h corresponding to the locking holes are formed.

The case body 9 is generally in the shape of a pot that opens to the output side. However, the input side of the case main body 9 facing the output side of the rotor main body 5 has a surface configuration corresponding to the rotor main body 5, and an annular groove 9a is formed in the outer edge portion thereof. The annular groove 9a has a depth and an outer circumference for accommodating the flange portion 5c of the rotor body 5, and a smooth bottom surface 9b capable of making surface contact with the end surface 5d of the rotor body 5.
And a smooth inner peripheral wall 9c concentric with the inner peripheral wall 5e of the magnet chamber 7 of the rotor main body 5 and capable of being fitted to the inner peripheral wall 5e, forming an annular fitting portion. or,
A cylindrical yoke 10 is provided at the center of the case body 9 on the input side.
Embedded therein, and two magnetoresistive elements (not shown) made of a compound semiconductor and provided with terminal portions 11a on the surface thereof.
Are connected in series and bonded to form a magnetoresistive element section 11. And in particular, the end surface 5 of the rotor body 5
When d and the bottom surface 9b of the annular groove 9a of the case body 9 are brought into surface contact with each other, the magnet 8 and the magnetoresistive element portion 11 are provided with a space between them.
An air gap of 0.1 mm or less is provided.
In addition, the protrusion 5f provided on the flange portion 5c of the rotor body 5
Correspondingly, the case body 9 is formed with a guide groove 9d having a width into which the protrusion 5f can be fitted. This guide groove 9d
As shown in FIG.
It has a circular arc shape of .degree., And acts as a stopper that prevents the rotor body 5 from rotating about 90.degree. Or more, as will be described later. The position where the guide groove 9d is formed is the angle sensor 1
The magnet 8 and the magnetoresistive element part 1 when assembled
1, the output potential difference is determined from the relative position to the rotor unit 2
The range is in a proportional relationship with the rotation angle of. That is,
As shown in FIG. 4, the magnet 8 is set to be rotatable in a range of about 45 ° to about 135 ° from a perpendicular line drawn from an intermediate terminal 12C described later to the center of the magnetoresistive element unit 11.

As shown in FIGS. 1 and 4, the magnetoresistive element portion 11
At both end portions of the terminal portion 11a and the middle bent portion, three input / output terminals 12 extending through the case body 9 to the output side, that is, both-end input terminals 12A and 12B and the intermediate terminal 1 are provided.
2C is provided. Also, these input / output terminals 12
A, 12B and 12C are further connected to the lead wires 1 through the printed circuit board 13 arranged on the output side of the case body 9.
4 is connected. The printed circuit board 13 is extremely useful for coping with and compensating for the resistance temperature characteristic of the magnetoresistive element portion 11, and in the present embodiment, as shown in FIGS. The temperature compensation of the magnetoresistive element portion 11 is performed by a series-parallel resistance method in which four fixed resistors 15 are provided on the back surface side of the wiring.

The spring portion 4 is composed of a coil-shaped spring 16 and two spring seats 17 and 18 fixing both ends thereof. A spring seat 17 for fixing one end of the spring 16
Has a ring shape with an L-shaped cross section and has locking holes 19 formed at three positions on its front surface so that the locking projections 5h of the rotor body 5 can be locked at the time of assembly. The spring seat 18 has a stepped ring body, and the spring 16 is attached to the small diameter portion 18a.
The other end is fixed, and the large diameter portion 18b can be fitted so that its inner diameter matches the outer diameter of the case body 9.

The non-contact type angle sensor 1 according to the embodiment of the present invention is configured as described above. First, an adhesive is applied to the peripheral portion of the printed circuit board 13 to which the fixed resistor 15 is attached in advance, and the input / output of the printed circuit board 13 is performed. The printed circuit board 13 is bonded to the stepped portion formed on the output side of the case body 9 while penetrating the input / output terminals 12A, 12B, 12C through the three holes formed for the terminal for use. Then, the printed circuit board 13 is fixed to the case body 9 by connecting the input / output terminals 12A, 12B and 12C to the printed wiring by soldering. Next, the inner peripheral wall 9c of the annular groove 9a of the case body 9 and the inner peripheral wall 5e of the magnet chamber 7 of the rotor body 5 are aligned with each other, and the flange portion 5 on the output side where the magnet 8 of the rotor body 5 is mounted.
By inserting c into the annular groove 9a on the input side of the case body 9 and bringing the end surface 5d of the flange portion 5c and the bottom surface 9b of the annular groove 9a into surface contact, the rotor body 5 and the case body 9 are fitted together. It Further, the spring 16 is covered on the rotor body 5 from the input side, and the three locking holes 19 of the spring seat 17 are fitted into and locked by the locking projections 5h on the front surface of the rotor body 5, and the large diameter portion of the spring seat 18 is secured. The case portion 3, the rotor portion 2 and the spring portion 4 can be integrated by applying an adhesive to the end surface of 18b and fitting the end portion 18b to the outer diameter of the case body 9 so as to be adhesively fixed.

In use, the non-contact type angle sensor 1 of the present invention assembled as described above should be coupled by fitting the input side of the rotor portion 2 into the shaft 6 (see FIG. 3) of the other side of the angle sensor 1. You can During this coupling operation, if the rotor portion 2 is twisted and turned, and the other shaft 6 is covered and the hand is released, the back tension of the spring 16 is used to urge the shaft 6 to return to its original shape. The protrusions 5b of the rotor portion 2 are meshed with each other. Therefore, it is easy to install and does not rattle during use.

If a constant current is applied to the magnetoresistive element portion 11 via the both-end input terminals 12A and 12B while the angle sensor 1 is attached to the other side of the angle sensor 1, the other side shaft 6 that rotates in accordance with the degree of processing or the like. When the magnet 8 of the rotor portion 2 rotates in response to the change of the magnetic flux passing through the magnetoresistive element portion 11 of the case portion 3, the resistance of the magnetoresistive element portion 11 changes. The potential difference extracted between the intermediate terminals 12C also changes rapidly. Therefore, the angle sensor of the present invention can be suitably used for setting the processing limit corresponding to the angle by the read voltage.

Further, although the pulling force of the magnetic force by the magnet 8 and the yoke 10 acts between the rotor portion 2 and the case portion 3, the present invention further uses the spring portion 4 to move the rotor portion 2 to the case portion 3.
Safety is expected by energizing.

In the present invention, the magnet 8 and the magnetoresistive element unit 11
A great feature is that the magnet 8 can be rotated while maintaining a narrow air gap of 0.1 mm or less between them. This is due to the magnetic force between the magnet 8 and the yoke 10 and the pressing force of the spring 16 described above. 5
This is possible because the end surface 5d of the flange portion 5c and the inner peripheral wall 5e of the magnet chamber 7 are brought into close surface contact with the bottom surface 9b of the annular groove 9a of the case body 9 and the inner peripheral wall 9c. is there. In this case, the rotation speed of the rotor portion 2 is low, and the pressing force of the rotor portion 2 is not strong enough to prevent the rotation, so that the wear on the contact surface does not pose a problem.

The rotor body and the case body of the present invention can be easily molded by plastic molding, and the contact surface and the fitting surface of the rotor body and the case body can be easily obtained as smooth surfaces.

The angle sensor of the present invention configured as described above has basic elements, and various combinations or changes in details can be made based on the basic elements. For example, the method of coupling with the other party can be changed. It is possible to easily change the output and the angle range by changing the pattern of the magnetoresistive element. Further, as described in the above-mentioned embodiment, a fixed resistor for temperature compensation can be built in freely and changed as required.

[Effect of device]

 The present invention has the following effects.

(1) The shape of the case main body including the magnetoresistive element, the yoke, and the terminal, and the rotor main body including the magnet is simplified,
Both are fitted together by a concentric annular fitting part, and the end faces are brought into contact with each other to be integrated, and the input end of the rotor body is engaged with the external rotation shaft. Since the rotor body is urged toward the case body side by the mounting spring and is rotated to the return side, there is no vibration or rattling due to the rotation of the rotor body, A narrow air gap with the resistance element can be maintained constant, and attachment / detachment to / from an external rotary shaft can be easily performed.

(2) The case body and the rotor body are formed concentrically, and the end faces are brought into contact with each other by fitting them at the peripheral annular fitting portion,
The input end of the rotor body is engaged with the external rotary shaft instead of the rotary shaft so that the product quality and performance can be maintained even if the shape is simplified. No need, expensive bearings or metal,
In addition, there are less restrictions on dimensional accuracy in processing and mounting, and it has become possible to manufacture more efficiently and cheaply than conventional products.

(3) Further, since the case main body and the rotor main body are formed by plastic molding, there is an effect that they can be manufactured particularly inexpensively.

[Brief description of drawings]

FIG. 1 is a front sectional view of an angle sensor according to an embodiment of the present invention, and FIG.
1 is an assembled perspective view of the angle sensor shown in FIG. 1, FIG. 3 is a side view seen from the direction of arrow X in FIG. 1, and FIG. 4 is an explanation of the relationship between the magnet and the magnetoresistive element in the embodiment shown in FIG. Figure,
FIG. 5 is a front sectional view of a conventional angle sensor. 1 ... Angle sensor, 2 ... Rotor part, 3 ... Case part, 4 ... Spring part, 5 ... Rotor body, 5b ... Projection 5c ... Flange part, 5d ... End face, 5e ... Inner peripheral wall, 5f ...... Protrusion 8 ...... Magnet, 9 ...... Case main body 9a ...... Annular groove, 9b ...... Bottom surface 9c ...... Inner peripheral wall, 9d ...... Guide groove 10 ...... Yoke, 11 ...... Magnetic resistance element part 12 ...... Input / output terminals, 13 ... Printed circuit board 16 ... Spring

Claims (2)

[Scope of utility model registration request] 1. The surface of two magnetoresistive elements connected in series and stacked on a yoke attached to a case main body is made to face a surface of a magnet attached to a rotor main body and rotating, and the magnet is attached. A non-contact angle sensor that measures the amount of rotation of the rotor body by a change in the amount of electricity at the intermediate terminal of the magnetoresistive element due to the rotation of
Concentric annular fitting portions are formed on the peripheral portions of the case main body and the rotor main body, and the case main body and the rotor main body are fitted to each other at the annular fitting portion, and end faces thereof are brought into contact with each other to form the magnetoresistive element. The front end of the rotor and the surface of the magnet and a predetermined gap are maintained, and the input side end of the rotor body is formed to be engageable with the external rotation shaft, and one end is fixed to the case body and the other end is fixed. A non-contact type angle sensor characterized in that a winding spring fixed to the rotor body urges the rotor body toward the case body and exerts a restoring force to the rotation of the rotor body. 2. The case body and the rotor body are molded by plastic molding, respectively.
Non-contact type angle sensor described.