JPH0419564A - Velocity sensor device - Google Patents

Abstract

PURPOSE:To continuously detect and output the velocity of moving object in non-contact, to reduce the accident damaging a band-shaped resistance body, and to attain an increase of durability by the fact that a specified electromotive force is generated between mutual electrodes in the orthogonally crossed direction to the moving direction of the moving object on the band-shaped resistance body when the mobile object is moved along the band-shaped resistance body. CONSTITUTION:The value of movement velocity of the moving object M can be continuously detected in non-contact and outputted. Since a movable yoke 2 is arranged at the position confronted with one side face of a fixing pedestal 1, the yoke 2 can be miniaturized and an entire face of another side of a resistance film 4 is fixed with a circuit board 3, and also since the entire face of another side of the board 3 is fixed on the pedestal 1, the exposed area of resistance film 4 is decreased. Consequently, the durability of resistance film 4 and board 3 can be increased, and also the resistance film 4 and output electrodes 5, 6 are effectively protected by an insulation film 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speed sensor device, and particularly to a speed sensor device that can detect the speed of a moving object over a wide range in a non-contact manner.

[Conventional technology]

A conventional example is shown in FIGS. 11 and 12. The conventional example shown in FIGS. 11 and 12 includes a strip substrate 50 with a resistive film 50A of a constant width disposed along the moving direction of a moving object M, and both ends of the strip substrate 50 in the width direction. The first and second output electrodes 5L are attached as resistive film to the
52.

Further, a yoke member 60 having a U-shaped cross section is disposed so as to sandwich the strip substrate 50 . The yoke member 60 is supported by the moving object M and can move integrally with the moving object M along the strip-shaped substrate 50.

A first magnet (e.g., a permanent magnet, the same applies hereinafter) 61 whose N pole is directed toward one surface of the strip substrate 50 is attached to the inner wall portion of the yoke member that faces the strip substrate 50 described above. , and a second magnet 6 with the south pole facing the other side.
2 are respectively installed on the other inner wall.

In this case, the above-mentioned resistive film 50A includes the first to second
Due to the magnet 6L 62, a constant amount of magnetic flux is constantly passing through the magnet 6L. Therefore, now the moving object M
When M moves along the strip-shaped substrate 50, for example, in the direction A, the resistive film 50A relatively cuts the magnetic flux, and as a result, the resistive film 50A has a magnetic flux perpendicular to the moving direction A of the moving object M according to Fleming's right-hand rule. Resistive film 50A in the direction of
Above, an electromotive force E proportional to the moving speed of the moving object M is generated as E=BfV (V).

Here, B indicates the magnetic flux density at that time, and 2 indicates the resistance film 50.
The width of the magnetic flux on A (more precisely, the width of the portion of the resistive film 50A in the area through which the magnetic flux penetrates) is shown, and ■ indicates the moving speed of the moving object M.

The electromotive force E on this resistive film 50A is generated under the same conditions at any position. This electromotive force E is taken out via the first and second output electrodes 51 and 52, amplified by an amplifier 80, and outputted to the outside as speed information of the moving object M.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional example, since the yoke member 60 is disposed so as to sandwich the strip-shaped substrate 50, the entire strip-shaped substrate 50 is always protruded to the outside. Otherwise, there will be an inconvenience that it will not function, which will not only hinder miniaturization of the entire device, but also that the protruding strip-shaped substrate portion will be easily hit by foreign matter, and therefore the strip-shaped substrate 50 will be easily damaged. Ta.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a non-contact speed sensor device that improves the disadvantages of the conventional example, and in particular, allows the entire device to be made smaller and has increased durability. .

[Means to solve the problem]

In the present invention, a strip resistor is disposed along the moving direction of a moving object and supported by a fixed base, and a strip resistor is disposed opposite to one surface of the strip resistor and moves integrally with the moving object. It has a movable yoke and first and second output electrodes attached along both ends of the strip resistor in the width direction. Furthermore, the moving yoke is equipped with a magnet of a predetermined size so that the end surface of the moving yoke facing the strip resistor forms one end surface of the magnetic path, and the other end surface of the magnetic path in the moving yoke is The structure is such that it is placed facing a part of the fixed base. This aims to achieve the above-mentioned purpose.

[For production]

When a moving object moves along the strip-shaped resistor, a predetermined electromotive force is generated between the electrodes on the strip-shaped resistor in a direction perpendicular to the moving direction of the moving object. The magnitude of this electromotive force is proportional to the moving speed of the moving object. In this case, the magnets installed on the moving object are arranged so that their magnetic flux penetrates the strip resistor, making assembly and maintenance inspection easier. ) is fixedly supported on a fixed base, so it is stable and does not resonate even with external vibrations, making it highly durable.

[First Embodiment of the Invention] Hereinafter, a first embodiment of the present invention will be described based on FIG. In the embodiment shown in FIG. 1, the moving direction of the moving object M (
The device includes a fixed base 1 disposed along a direction perpendicular to the paper plane of FIG. 1, and a movable yoke 2 disposed opposite to one surface of the fixed base 1.

The fixed base 1 is made of, for example, a magnetic material, consists of a band-shaped member having a constant thickness as a whole, and is fixed to a side wall W of a case or the like by screws or the like. The central portion of the outer surface of the fixed base 1 (the central portion of one surface) projects somewhat toward the movable yoke 2, and the projecting end surface forms a relatively wide flat surface. A circuit board 3 made of an insulating material is fixedly mounted on the protruding end surface IA of the fixed base 1 along the moving direction of the movable yoke 2 described above. Specifically, this circuit board 3 is installed in the lower half region of the protruding end surface IA of the fixed base 1 described above in FIG. 1, thereby exposing the upper half region of the protruding end surface IA. It has become a form.

On the outer surface of the circuit board 3, there is a resistance l! as a strip resistor. 4
is installed. This resistive film 4 is made of a conductive material and is disposed along the moving direction of the moving yoke 2.

This resistive film 4 is actually attached on the circuit board 3 by a technique such as thick film printing.

A first output electrode 5 and a second output electrode 6 are formed on both ends of the resistive film 4 in the width direction (the upper and lower ends in FIG. 1) by a technique such as thick film printing. are attached along the moving direction of the moving yoke 2 described above. In this case, the distance L between the first and second output electrodes
(see Figure 2) is always constant no matter where it is located.

The resistive film 4 and the first and second output electrodes 56 are covered with an insulating film 7 over their entire externally exposed surfaces.

The movable yoke 2 has a substantially U-shaped surface parallel to the direction perpendicular to its movement direction, and is fixedly mounted on the movable object M with its opening side facing the fixed base 1 side described above. There is.

This movable yoke 2 is equipped with a permanent magnet 1o so as to form a magnetic path along its U-shape.

To explain this in more detail, the movable yoke 2 includes the two protrusions 2A and 2B as described above.

One protruding portion 2A of this movable yoke 2 has an end surface 2a thereof.
is disposed facing the resistive film 4 described above.

Further, the other protruding portion 2B of the movable yoke 2 has an end surface 2B of the movable yoke 2.
b is arranged to face the exposed surface of the protruding end surface IA of the fixed base l mentioned above.

One protrusion 2A of the movable yoke 2 is formed of a permanent magnet 10 in this embodiment. In this case, the magnetic poles of the permanent magnet (1) 0 are set such that the north pole faces the resistive film 4 and the south pole is set on the opposite side. Therefore, this movable yoke 2
A magnetic path R is formed in the fixed base L as shown by the dotted line in FIG. Reference numeral 20 indicates an amplifier.

Next, the operation of the first embodiment will be explained.

If the moving object M moves in a direction perpendicular to the paper surface of FIG. 1 from the front surface to the back surface of the paper surface, there will be an origin on the resistive film 4 in the direction of the arrow Y shown on the second surface according to Fleming's right-hand rule. Electric power E is generated.

Here, the magnitude of the electromotive force E is E=BNV (Vl) as in the case of the conventional example described above.Here, B indicates the magnetic flux density of the permanent magnet 10 that crosses the resistive film 4, and The moving speed of the moving object M equipped with 2, l indicates the width of the magnetic flux on the resistive film 4 in the direction orthogonal to the moving direction.

The magnitude of this electromotive force E is proportional to the moving speed V of the moving object M since the magnetic flux density B and the magnetic flux width I are constant. This electromotive force E is detected by the first and second output electrodes, amplified to a predetermined level via the amplifier 20, and output to the outside.

In this manner, in the first embodiment, the magnitude of the moving speed of the moving object M can be continuously detected and output almost without contact. In addition, since the movable yoke 2 is disposed at a position facing one surface of the fixed base l, the size of the movable yoke 2 can be set freely.
This makes it possible to downsize the movable yoke 2, and it can be configured such that the entire other surface of the resistive film 4 is fixed to the circuit board 3 and the entire other surface of the circuit board 3 is fixed to the fixed base 1. As a result, the exposed portion of the resistive film 4 is reduced,
Therefore, the durability of the resistive film 4 and the circuit board 3 can be significantly increased. This has the advantage that the second output electrodes 5, 6 are effectively protected.

In the embodiment shown in FIG. 1, the circuit board 3 is installed along the lower edge of the protruding end surface IA of the fixed base 1, but the circuit board 3 is shown in FIG. A size that covers the entire protruding end surface IA of the fixed substrate 1 may be used. Furthermore, when the fixed base 1 is made of a magnetic material, a groove IB of a predetermined depth is formed in the center along the moving direction of the moving object M, as shown in FIG. may be formed. This has the advantage that the magnetic flux of the permanent magnet 10 tends to be orthogonal to the resistive film 4, and therefore the magnitude of the electromotive force (2) increases. Further, the movable yoke 2 may be formed so that the permanent magnet 1o is fixed to the center of the movable yoke 2 so as to have a U-shaped cross section as a whole, as shown in FIG.

Furthermore, as for the magnet, although the case where a permanent magnet is used is illustrated, an electromagnet may be used.

Furthermore, although the first embodiment exemplifies the case where the resistive film 4 attached to the circuit board 3 is used as the strip-shaped resistor, the present invention is not particularly limited to this. The circuit board 3 may be omitted by using a plate material and covering it with an insulating film as an insulating member.

[Second example] Next, a second embodiment will be explained based on FIG. 6.

In the second embodiment shown in FIG. 6, the width of the protruding end surface IA of the fixed base 1 is set to be relatively small.

A relatively large cutout portion 1c is provided at the upper end corner of the fixed base 1 along the moving direction of the moving object M. Also,
The movable yoke 2 having a U-shaped cross section has protrusions 2A and 2B.
Each is equipped with a separate permanent magnet 21°22.

And this protrusion 2A.

Of the protrusions 2B, the protrusion 2B on the side that is installed facing the exposed surface of the fixed base 1 is the cutout part IC of the fixed base 1 described above.
It protrudes greatly inward.

The other configurations are the same as those of the first embodiment described above.

Even in this case, in addition to having the same effect as the first embodiment described above, in particular, the other protrusion 2B is connected to the permanent magnet 2.
Since the fixed base 1 and the fixed base 1 are protruded deeply into the cutout IC along with the fixed base 1, the amount of interlinkage magnetic flux with respect to the resistive film 4 is significantly increased, which has the advantage that the sensor output sensitivity can be increased. .

[Third example] Next, a third embodiment will be described based on FIG. 7.

The third embodiment shown in FIG. 7 differs from the above-described second embodiment in that the direction of the other permanent magnet 22 is changed from one permanent magnet 22 to another.
The orientation is set to be changed by 90 degrees with respect to the orientation of 1. The other configurations are the same as those of the second embodiment described above.

Even in this case, it is possible to obtain almost the same effects as in the second embodiment described above, and in particular, the magnetic path within the fixed base 1 can be set short, so that the fixed base 1 can be miniaturized. It has the advantage of being able to

[Fourth example] Next, a fourth embodiment will be described based on FIG. 8.

In the fourth embodiment shown in FIG. 8, the first to second output electrodes in FIG.
A third output electrode 30 is provided along each output electrode 5.6. This third output electrode 30 is grounded. Furthermore, the protrusions 2A and 2B of the movable yoke 2 are formed by permanent magnets 21 and 22, and their respective end surfaces 2a and 2
b are set to have different magnetic poles. In the embodiment shown in FIG. 8, the permanent magnets 21, 22 are arranged such that the end surface of the protrusion 2A forms the N pole, and the end surface of the protrusion 2B forms the S pole.
is equipped with. One end surface 2a of the moving yoke 2 is arranged to face the resistive film 4 between the second output electrode 6 and the third output electrode 30. Further, the other end surface 2b of the moving yoke 2 has a first output electrode 5 and a third
The resistive film 4 is disposed facing the resistive film 4 between the output electrode 30 and the output electrode 30 of the resistive film 4 . Further, an adding circuit 31 is provided which adds the signals taken out from each of the first and second output electrodes 5.6 and sends the sum to the outside. The symbol IS indicates a groove provided in the fixed base 1 along the moving direction of the moving object M.

The other configurations are the same as those of the first embodiment described above.

Now, in FIG. 8, when the movable yoke 2 moves in the opposite direction to that in the first embodiment (from the back side to the front side of the paper), on the resistive film 4 as a strip resistor, An electromotive force E in the direction toward the third electrode 30, that is, an electromotive force E of the same level at a positive potential when viewed from each of the first and second output electrodes 56 is generated. Then, these two electromotive forces E are immediately added together by an adder circuit 31 and output to the outside.

In this way, in the fourth embodiment shown in FIG.
It is possible to detect and output a signal approximately twice as large as that in the case of the first embodiment described above, and the protrusion 2A of the movable yoke 2
, 2B are both arranged facing each other on the resistive film 4, so that the detection sensitivity can be doubled, which has the advantage that the movable yoke 2 can be sufficiently miniaturized.

[Fifth example] Next, a fifth embodiment will be described based on FIG. 9.

The embodiment shown in FIG. 9 uses three resistive films 4 equivalent to the resistive film 4 used in the embodiment disclosed in FIG. ,
Between 43 and 43 is an insulating thin film 7. .

7□ is inserted. Code 5. ．． 6. ;5,,L
; 53 and 63 are the respective resistance films 4I4z and 4z
The first and second output electrodes provided in the figure are shown. Also, 5° indicates a common ground electrode.

The almost same level of electromotive force E detected by these six output electrodes 51 to 53 and 6 to 63 is generated by the signal adder 32.
are added and output externally.

Therefore, in the embodiment shown in FIG. 9, it is possible to obtain an output voltage that is five to six times more sensitive than normal.

Other configurations and effects are the same as those of the embodiment shown in FIG. 8 described above.

[Sixth Example] Next, a sixth example will be described based on FIG. 10. The embodiment shown in FIG. 10 is characterized in that a plurality of magnets are provided on both sides of the moving yoke, and strip-shaped resistors are arranged on both sides of the moving yoke to face the magnets. have.

That is, in FIG. 10, the resistance films 14 and 15 as the first and second strip resistors
They are installed facing each other at a predetermined interval along the 1° movement direction. The resistive films 14 and 15 are supported by fixed bases 11A and IIB made of magnetic material.

The moving yoke 210 has resistive films 14 .
It protrudes between 15. This moving yoke 2. . is supported by the aforementioned moving object M1° and moves integrally with the moving object M1°.

At both ends (upper and lower ends in FIG. 10) of the two resistive films 14 and 15, there are first and second electrodes of 14A, respectively.
, 14B and 15A, 15B are installed in the same manner as in the case of FIG. 8 described above.

A ground electrode 14C is provided in the center of one of the resistive films 14 along the first and second electrodes 14A and 14B.
is equipped with. Also in the center part of the other resistive film 15,
A similar ground electrode 15C is provided.

A plurality of magnets (in this embodiment, permanent magnet) 16A, 16B, 1
Equipped with 7A and 17B. Each of the plurality of magnets 16A, 16B, 17A, and 17B is configured to form one closed magnetic path as a whole via the fixed bases 11A and IIB, the resistive film 14.15, and the movable yoke 210. The orientation of each magnet is set.

The electromotive force E induced in the resistive film 14.15 described above as the movable yoke 2100 moves is applied to each output electrode 14.
The signals are taken out from A, 14B and 15A, 15B, are added together via a signal adding means 33, and are output to the outside. The rest of the structure is similar to the embodiment shown in FIG. 8 described above.

In this way, in addition to having the same effect as the embodiment shown in FIG. Since it is symmetrical, the attraction effect due to magnetism is canceled out. For this reason, the movable yoke 2. . This has the advantage that side movement can be performed more smoothly.

〔Effect of the invention〕

As described above, according to the present invention, the moving speed of a moving object can be continuously detected and output without contact, and therefore damage accidents to the strip resistor can be reduced and durability can be increased. Since the movable yoke is arranged so as to face one side of the fixed base, the size of the movable yoke can be controlled relatively without having to do with the size of the fixed base or the strip resistor. This allows the movable yoke to be made smaller, and since the other side of the strip resistor is fixed to the fixed base via an insulating member, the externally exposed surface is reduced. In addition, the probability of hitting foreign objects is greatly reduced, and at the same time, the durability against external vibrations is increased, which significantly increases the durability of the strip resistor and output electrode parts, which is an unprecedented non-contact type. A speed sensor device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the first embodiment of the present invention, FIG. 2 is an explanatory diagram showing the action of the strip resistor portion in FIG. 1, and FIG. 3 is a partial view of the circuit board portion in FIG. 1. 4 is a longitudinal sectional view showing an example of an improved case; FIG. 4 is a longitudinal sectional view showing a modification of the first embodiment; FIG. 5 is a sectional view showing another example of the movable yoke portion in FIG. 4; The figure is a longitudinal sectional view showing the second embodiment, Fig. 7 is a longitudinal sectional view showing the third embodiment, Fig. 8 is a longitudinal sectional view showing the fourth embodiment, and Fig. 9 is a longitudinal sectional view showing the fifth embodiment. longitudinal section,
FIG. 10 is a longitudinal sectional view showing the sixth embodiment, FIG. 11 is a front view showing the conventional example, and FIG. 12 is a sectional view taken along the line X--X in FIG. 11. 1, IIA, IIB... fixed base, 2, 2.0...
Movable yoke, 2a...One end surface of the movable yoke, 2b
. . . the other end surface of the movable yoke, 3 . . . a circuit board as an insulating member, 4, 4. ．． 4□, 4. ．． 14.15...
- Resistive film as a strip resistor, 5, 51-5. . 14A, 14B...first output electrode, 6,6. ．． 6z
, 63.15A, 15B...Second output electrode, 7°71.7□...Insulating film, 10.21, 22.16A. 16B. 7A 7B...Permanent magnet, M...Moving object, R...Magnetic path.

Claims (5)

[Claims] (1). A band-shaped resistor disposed along the moving direction of the moving object and supported by a fixed base, and a movable yoke disposed opposite to one surface of the band-shaped resistor and moving integrally with the moving object. , first and second output electrodes are attached to the strip resistor and output a predetermined signal generated in the strip resistor, and an end face portion of the movable yoke facing the strip resistor is connected to a magnetic path. The movable yoke is equipped with a magnet of a predetermined size so as to form one end surface, and the other end surface of the magnetic path in the movable yoke is arranged to face a part of the fixed base. Characteristic speed sensor device. (2). 2. The speed sensor device according to claim 1, wherein two of the magnets are used, and the two magnets are installed at each of the protruding end portions of one and the other of the magnetic paths in the moving yoke. (3). 2. The speed sensor device according to claim 1, wherein at least one surface of the strip resistor is covered with an insulating film along with each of the first and second electrodes. (4). A band-shaped resistor disposed along the moving direction of the moving object and supported by a fixed base, and a movable yoke disposed opposite to one surface of the band-shaped resistor and moving integrally with the moving object. a first and a second resistor are provided along both ends of the strip resistor in the width direction.
A ground electrode is provided at an intermediate position between the first and second output electrodes along each of the first and second output electrodes, and a cross section perpendicular to the moving direction of the moving yoke is provided. is formed into a U-shape, and this cross section U
The movable yoke is equipped with a magnet of a predetermined size so that one end face and the other end face of the movable yoke formed in a letter shape form different magnetic poles, and one end face of the movable yoke is connected to the first end face. The movable yoke is disposed opposite to the strip resistor located on the output electrode side, and the other end surface of the movable yoke is disposed opposite to the strip resistor located on the second output electrode side, and the first and a signal adding means for adding signals output from each of the second output electrodes and sending the sum to the outside. (5). first and second strip-shaped resistors arranged opposite to each other at a predetermined interval along the moving direction of the moving object and supported by a fixed base; disposed opposite to each opposing surface of each of the strip-shaped resistors; a moving yoke that moves integrally with the moving object;
and a second output electrode respectively, and the first and second output electrodes are provided at intermediate portions of the first and second strip-shaped resistors.
A ground electrode is provided along each output electrode of the first and second strip resistors, and a plurality of magnets are provided on both sides of the movable yoke facing two surfaces of each of the first and second strip resistors separated by the ground electrode. At the same time, the orientation of each of the plurality of magnets is set so that each of the plurality of magnets collectively forms one closed magnetic path via the fixed base, the strip resistor, and the movable yoke, and A speed sensor device comprising signal adding means for extracting electromotive force induced in the strip resistor as it moves from each of the first and second output electrodes, and for adding and outputting the sum.