JPH0769336B2 - Speed sensor device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed sensor device, and more particularly to a speed sensor device capable of non-contact detection of the speed of a moving object over a wide range.

[Conventional technology]

11 to 12 show conventional examples. In the conventional example shown in FIG. 11 to FIG. 12, a strip-shaped substrate 50 with a resistance film 50A having a constant width is arranged along the moving direction of a moving object M, and both end portions in the width direction of the strip-shaped substrate 50. And a first output electrode 51 and a second output electrode 52 mounted for the resistance film.

Further, a yoke member 60 having a U-shaped cross section is arranged 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 substrate 50.

On the inner wall portion of the yoke member 60 facing the above-mentioned strip-shaped substrate 50, a first magnet (for example, a permanent magnet, the same applies hereinafter) 61 whose N pole is directed to one surface of the strip-shaped substrate 50 is formed on one inner wall. And a second magnet 62 with the south pole facing the other surface is mounted on the other inner wall, respectively.

In this case, the above-mentioned resistance film 50A is in a state in which a magnetic flux of a certain magnitude is always passing through by the first and second magnets 61, 62. Therefore, when the moving object M moves along the strip substrate 50 in the direction A, for example, the resistance film 50A relatively cuts off the magnetic flux.
In 0A, an electromotive force E having a magnitude proportional to the moving speed of the moving object M is E = Blv [on the resistive film 50A in the direction orthogonal to the moving direction A of the moving object M according to Fleming's right-hand rule. V].

Where B is the magnetic flux density at that time, and 1 is the resistance film 50A.
The width of the upper magnetic flux (more precisely, the resistance film in the region where the magnetic flux penetrates)
(Width of 50 A portion), and v indicates the moving speed of the moving object M.

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

[Problems to be Solved by the Invention]

However, in the above conventional example, since the yoke member 60 is arranged so as to sandwich the strip substrate 50,
There is an inconvenience that it does not function unless the entire strip-shaped substrate 50 is always provided to the outside, which not only hinders downsizing of the entire apparatus but is also susceptible to the influence of external noise. There is a disadvantage in that foreign matter is likely to hit the provided strip-shaped substrate portion, and thus the strip-shaped substrate 50 is easily damaged.

[Object of the Invention]

The present invention improves the disadvantages of such a conventional example, and in particular, speed information can always be detected under the same condition regardless of the size of the moving range of a moving object, and the entire device can be downsized, and the entire device can be downsized. It is an object of the present invention to provide a highly reliable non-contact type speed sensor device having increased durability.

[Means for Solving the Problems]

According to the present invention, the strip-shaped resistor disposed along the moving direction of the moving object and supported by the fixed base, and the strip-shaped resistor disposed on one surface side of the strip-shaped resistor to move integrally with the moving object described above. It has a moving yoke and first and second output electrodes which are mounted parallel to each other at both ends in the width direction of the strip resistor and which output predetermined signals generated in the strip resistor.

Among them, the moving yoke is formed of a magnetic member having a U-shaped cross section, which has two protruding portions facing the fixed base and moves integrally with the moving object. Further, one projecting portion of the moving yoke is arranged so as to face one surface of the strip resistor, and the other projecting portion is arranged so as to face a predetermined position on the same surface as the mounting surface of the strip resistor. Set up.

Further, the moving yoke is equipped with a magnet of a predetermined size so that the end face portion of one protruding portion of the moving yoke facing the strip-shaped resistor forms one end face of the magnetic path.

Then, the above-mentioned strip-shaped resistor is fixed to the fixed base so that the other surface of the strip-shaped resistor is covered with the fixed base. This aims to achieve the above-mentioned object.

[Action]

When the moving object moves along the strip resistor, a predetermined electromotive force is generated between the electrodes on the strip resistor in a direction orthogonal 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 mounted on the moving object are arranged so that the magnetic flux penetrates the strip-shaped resistor, which facilitates not only assembly but also maintenance and inspection. Is stable and does not resonate against external vibrations because it is fixedly supported by a fixed base, and is less affected by external noise.

[First Embodiment of the Invention] A first embodiment of the present invention will be described below with reference to FIG. In the embodiment shown in FIG. 1, the fixed base 1 is arranged along the moving direction of the moving object M (the direction orthogonal to the paper surface of FIG. 1), and one surface of the fixed base 1 is provided. The movable yoke 2 is provided so as to face each other.

The fixed base 1 is made of, for example, a magnetic material, and is made of a plate-shaped member having a predetermined thickness as a whole and fixed to a side wall W of a case or the like by screws.
The central portion of the outer surface of this fixed base 1 (the central portion of one surface) is
It is projected somewhat toward the movable yoke 2, and its protruding end surface forms a relatively wide flat surface. This fixed base 1
A circuit board 3 made of an insulating material is fixedly mounted on the protruding end surface 1A of the movable yoke 2 along the moving direction thereof.
This circuit board 3 is specifically provided in the lower half region of the above-mentioned projecting end face 1A of the fixed base 1 in FIG. 1, whereby the upper half region of the projecting end face 1A is exposed. It is in the form.

On the outer surface of the circuit board 3, a resistance film 4 as a strip-shaped resistor is formed.
However, it is fixed on the back side. The resistance film 4 is made of a conductive material and is arranged along the moving direction of the moving yoke 2. The resistance film 4 is actually provided on the circuit board 3 by a technique such as thick film printing. Therefore, the resistance values in the width direction are set to have the same magnitude as a whole.

At both end portions (upper and lower end portions in FIG. 1) of the resistance film 4 in the width direction, the first output electrode 5 and the second output electrode 6 are also formed on the resistance film 4 by a method such as thick film printing. Are provided in parallel along the moving direction of the moving yoke 2 described above. In this case, the distance L (see FIG. 2) between the first and second output electrodes is always constant at any position.

The resistance film 4, the first and second output electrodes 5 and 6 are covered with a common insulating film 7 on the entire outer exposed surface thereof.

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

The movable yoke 2 is equipped with a permanent magnet 10 so as to form a magnetic path along the U-shape.

More specifically, the movable yoke 2 has the two protrusions 2A and 2B as described above. The one protruding portion 2A of the movable yoke 2 is arranged such that its end face 2a faces the above-mentioned resistance film 4. The other protruding portion 2B of the movable yoke 2 is arranged such that its end surface 2b faces the exposed surface of the protruding end surface 1A of the fixed base 1 described above.

One protruding portion 2A of the movable yoke 2 is formed by a permanent magnet 10 in this embodiment. In this case, the permanent magnet 10
In the magnetic pole of, the N pole is set to face the resistance film 4, and the S pole is set to the opposite side. Therefore, a magnetic path R is formed in the movable yoke 2 and the fixed base 1 as shown by the dotted line in FIG. Reference numeral 20 indicates an amplifier.

Next, the operation of the first embodiment will be described. Now, when the moving object M moves in the direction orthogonal to the paper surface of FIG. 1 from the front surface to the back surface of the paper surface, the resistance film 4 is raised in the direction of the arrow Y shown in FIG. 2 according to Fleming's right-hand rule. Electric power E is generated.

Here, the magnitude of the electromotive force E is E = Blv [V] as in the case of the conventional example described above. Here, B represents the magnetic flux density of the permanent magnet 10 that traverses the resistance film 4, and v represents the moving object M equipped with the movable yoke 2.
, L is the width of the magnetic flux in the direction orthogonal to the moving direction on the resistance film 4.

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

As described above, in the first embodiment, the magnitude of the moving speed of the moving object M can be continuously detected and output with almost no contact. Further, since the movable yoke 2 is arranged at a position facing one surface of the fixed base 1, the size of the movable yoke 2 can be freely set, which reduces the size of the movable yoke 2. Since the other surface of the resistance film 4 is fixed to the circuit board 3 and the other surface of the circuit board 3 is fixed to the fixed base 1, the resistance film 4 is exposed. Therefore, the durability of the resistance film 4 and the circuit board 3 can be significantly increased, and the resistance film 4 and the first and second output electrodes 5, 6 are effectively provided by the insulating film 7. It has the advantage of being protected.

Here, in the embodiment of FIG. 1 described above, the case where the circuit board 3 is mounted by the lower end edge of the projecting end surface 1A of the fixed base 1 is illustrated, but this circuit board 3 is shown in FIG. As described above, a size that covers the entire protruding end surface 1A of the fixed substrate 1 may be used. When the fixed base 1 is made of a magnetic material, as shown in FIG. 4, a groove 1B having a predetermined depth along the moving direction of the moving object M is formed at the center thereof. You may form. This way,
The magnetic flux of the permanent magnet 10 is likely to be orthogonal to the resistance film 4, and therefore, there is an advantage that the magnitude of the electromotive force E is increased. The movable yoke 2 may be formed so that the permanent magnet 10 is fixed to the central portion of the movable yoke 2 as shown in FIG.

Further, as the magnet, a case where a permanent magnet is used has been exemplified, but an electromagnet may be used.

Further, as the strip-shaped resistor, the case where the resistance film 4 attached to the circuit board 3 is used in the first embodiment has been illustrated, but the present invention is not particularly limited to this, and for example, the conductive film having an appropriate thickness is used. The circuit board 3 may be omitted by using a plate material and covering it with an insulating film as an insulating member.

[Second Embodiment] Next, a second embodiment will be described with reference to FIG. In the second embodiment shown in FIG. 6, the width of the projecting end surface 1A 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. Further, in the movable yoke 2 having a U-shaped cross section, the protrusions 2A and 2B have separate permanent magnets 21,
Equipped with 22. And, of these protrusions 2A, 2B,
The protrusion 2B on the side facing the exposed surface of the fixed base 1 is largely projected toward the inside of the cutout portion 1C of the fixed base 1 described above.

As described above, in the second embodiment, the end faces of the projecting portions 2A and 2B of the movable yoke 2 forming the magnetic poles are arranged so as to face one surface side of the fixed base 1 described above. The other structure is the same as that of the first embodiment described above.

Even in this case, in addition to the same effects as the above-described first embodiment, in particular, since the other protruding portion 2B together with the permanent magnet 22 is deeply provided in the fixed base 1 cutout portion 1C, The amount of interlinkage magnetic flux with respect to the resistance film 4 is significantly increased, which has the advantage that the sensor output sensitivity can be increased.

Here, an application example of the above-described second embodiment will be described with reference to FIG.

The application example of the second embodiment shown in FIG.
In the embodiment, the orientation of the other permanent magnet 22 is set to be changed by 90 degrees with respect to the orientation of the one permanent magnet 21. The other structure is the same as that of the second embodiment described above.

In this way as well, it is possible to obtain substantially the same operational effects as the above-described second embodiment, and in particular, the magnetic path in the fixed 0 base 1 can be set short, so that the fixed base 1 can be made compact. The advantage is that

[Third Embodiment] Next, a third embodiment will be described with reference to FIG.

In the third embodiment shown in FIG. 8, the first electrode is provided at the intermediate portion of each of the first and second output electrodes shown in FIG.
Through the third output electrode 30 along each of the second output electrodes 5,6
Is equipped with. The third output electrode 30 is grounded. Further, the protruding portions 2A and 2B of the movable yoke 2 are provided with permanent magnets 21 and 22.
And the end faces 2a and 2b thereof are set to have different magnetic poles. In the embodiment of FIG. 8, the permanent magnets 21 and 22 are provided so that the end face of the protrusion 2A forms the N pole and the end face of the protrusion 2B forms the S pole. The one end surface 2a of the moving yoke 2 is arranged so as to face the resistance film 4 between the second output electrode 6 and the third output electrode 30. The other end surface 2b of the moving yoke 2 is arranged so as to face the resistance film 4 between the first output electrode 5 and the third output electrode 30. Furthermore, each of the first and second output electrodes
An adder circuit 31 for adding the signals taken out from 5, 6 and sending them to the outside is provided. Reference numeral 1S indicates a groove provided in the fixed base 1 along the moving direction of the moving object M.

The other structure is similar to that of the first embodiment described above.

Now, in FIG. 8, when the moving yoke 2 is moved in the direction opposite to the case of the first embodiment (the direction from the back surface of the paper to the front surface side), on the resistance film 4 as the strip-shaped resistor, An electromotive force 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 the first and second output electrodes 5 and 6 is generated. The two electromotive forces E are immediately added by the adder circuit 31 and output to the outside.

Thus, in the third embodiment shown in FIG.
It is possible to detect and output a signal that is almost twice as large as that in the case of the first embodiment described above, and the protruding portions 2A, 2 of the moving yoke 2 can be detected.
Since B is arranged on the resistive film 4 so as to face each other,
Since the detection sensitivity can be doubled, there is an advantage that the moving yoke 2 can be sufficiently miniaturized.

Fourth Embodiment Next, a fourth embodiment will be described with reference to FIG. EXAMPLE shown in FIG. 9 is the equivalent of a resistive film 4 used in the embodiments disclosed in the eighth the previously described figures, the use by laminating three sheets, each resistive film 4 _1, 4 between the _2, 4 ₃ is obtained by interposing an insulating film _71, 7 _2. Codes 5 ₁ and 6 ₁ ;
Reference _numerals 5 ₂ , 6 ₂ ; 5 ₃ , 6 ₃ denote the first and second output electrodes provided on the resistance films 4 ₁ , 4 ₂ , 4 ₃ , respectively. Reference numeral ₅₀ indicates a common ground electrode.

Then, the electromotive force E of approximately the same level detected by these six output electrodes 5 _{1 to} 5 ₃ and 6 _{1 to} 6 ₃ is added by the signal adder 32 and output to the outside.

Therefore, in the embodiment shown in FIG. 9, it is possible to obtain an output voltage having a sensitivity that is 5 to 6 times higher than that of the normal case.

The other structure and effects are the same as those of the embodiment shown in FIG.

[Fifth Embodiment] Next, a fifth embodiment will be described with reference to FIG. This first
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 so as to face the both sides of the moving yoke so as to face the magnets. ing.

That is, in FIG. 10, the resistance films 14 and 15 as the first and second two band-shaped resistors are provided opposite to each other at a predetermined interval along the moving direction of the moving object M ₁₀ . The resistance films 14 and 15 are supported by fixed bases 11A and 11B made of a magnetic material.

Moving the yoke 2 ₁₀ is projected between the equipped to face resistance films 14 and 15. The mobile yoke 2 ₁₀ is supported on the moving object M ₁₀ described above, so as to move the moving object M ₁₀ and integrally.

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

A ground electrode 14C is provided in the central portion of one of the resistance films 14 along the above-mentioned first and second electrodes 14A and 14B. A similar ground electrode 15C is also provided in the central portion of the other resistance film 15.

The ground electrode 1 of each of the one and the other resistance films 14 and 15 described above.
Facing each of the two surfaces separated by 4C and 15C,
On both sides of the moving yoke 2 ₁₀ described above, 16A, 16B, 17A, 17B is equipped (the permanent magnet in this example) a plurality of magnets. Then, each of the plurality of magnets 16A, 16B, 17A, 17B is to form a generally closed magnetic path via the mobile yoke 2 ₁₀ fixed base 11A described above, and 11B and the resistor film 14 and 15 The orientation of each magnet is set to.

Then, the above-described the movement of the moving yoke 2 ₁₀ resistive film 1
The electromotive force E induced in 4, 15 is the output electrodes 14A, 14B and 1
The signals are taken out from 5A and 15B, added through the signal adding means 33, and output to the outside. Other configurations are similar to those of the embodiment shown in FIG.

By doing so, in addition to the effects and advantages similar to those of the embodiment shown in FIG. 8 described above, the output level can be greatly increased, and further, the magnetic circuit can be made substantially in the plane orthogonal to the moving direction. The symmetry cancels the magnetic attraction. Therefore, there is an advantage that it is possible to perform the movement of the moving yoke 2 ₁₀ side more smoothly.

〔The invention's effect〕

As described above, according to the present invention, the characteristic that the strip-shaped resistor is used, that is, the magnitude of the velocity of the moving yoke can be expressed as it is by the magnitude of the interlinkage magnetic flux, regardless of the position of the moving yoke, Since the protrusions on one side and the other side of the moving yoke are arranged in the same direction as described above, the linking condition with the strip resistor should always be set to the same condition no matter where the moving yoke is located. Therefore, the speed of the moving yoke can always be detected accurately regardless of the moving distance of the moving yoke, and at the same time, the other surface of the strip resistor is covered with the fixed base. Since it is fixed to the fixed base, external noise is received on only one surface (front surface) compared to the case of the conventional example where external noise is received on both front and back surfaces, so the effect of external noise can be clearly halved. You can At that point, the speed information of the moving yoke can always be detected and output with high sensitivity and high accuracy, and since there is no protrusion from the fixed base side, downsizing of the entire device and strip-shaped resistor part It is possible to significantly reduce the probability of hitting a foreign object, and therefore, it is possible to significantly reduce the occurrence of damage accidents on the band-shaped resistor portion, and in this respect, the durability and reliability of the entire device can be increased. It is possible to provide an excellent non-contact type speed sensor device which is not found in the market.

[Brief description of drawings]

1 is a longitudinal sectional view showing a first embodiment of the present invention, FIG. 2 is an explanatory view showing the action of the strip-shaped resistor portion of FIG. 1, and FIG. 3 is a part of the circuit board portion in FIG. FIG. 4 is a vertical sectional view showing an example of a modified case, FIG. 4 is a vertical sectional view showing a modified example of the first embodiment, FIG. 5 is a sectional view showing another example of the movable yoke portion in FIG. 4, and FIG. FIG. 8 is a vertical sectional view showing a second embodiment, FIG. 7 is a vertical sectional view showing an application example of the second embodiment, FIG. 8 is a vertical sectional view showing a third embodiment, and FIG. 9 is a fourth embodiment. Fig. 10 is a vertical sectional view showing an example, Fig. 10 is a vertical sectional view showing a fifth embodiment, Fig. 11 is a front view showing a conventional example, and Fig. 12 is a sectional view taken along line XX in Fig. 11. is there. 1,11A, 11B …… Fixed base, 2,2 ₁₀ …… Movable yoke, 2a ……
One end surface of the movable yoke, 2b ... The other end surface of the movable yoke, 3 ... Circuit board as an insulating member, 4, 4 ₁ , 4 ₂ , 4 ₃ , 1,
4,15 ...... Resistance film as strip-shaped resistor, 5,5 _{1 to} 5 ₃ , 14, A, 14B
...... first output _{electrode, 6,6 1, 6 2, 6} 3, 15A, 15B ...... second output electrodes, 7,7 _1, 7 ₂ ...... insulating film, 10,21,22,16A, 16B, 17
A, 17B ... Permanent magnet, M ... Moving object, R ... Magnetic path.

Claims (5)

[Claims] 1. A strip-shaped resistor provided along a moving direction of a moving object and supported by a fixed base, and a strip-shaped resistor provided on one surface side of the strip-shaped resistor to move integrally with the moving object. A moving yoke, and first and second output electrodes that are mounted in parallel with each other on both end portions in the width direction of the strip resistor and that output predetermined signals generated in the strip resistor. Is formed of a magnetic member having a U-shaped cross section, which has two projecting portions facing the fixed base and moves integrally with the moving object, and one projecting portion of this moving yoke is the strip-shaped resistor. One of the surfaces is disposed so as to face the other surface, and the other protruding portion is disposed so as to face a predetermined portion of the surface on the same side as the mounting surface of the strip-shaped resistor, and faces the strip-shaped resistor of the moving yoke. The end face of one of the protrusions has a predetermined large size so as to form one end face of the magnetic path. Is a equipped with a magnet on the moving yoke, the speed sensor device, characterized in that fixed to the fixed base and the other surface of the strip resistive element so as to cover at the fixed base. 2. The moving yoke comprises two magnets, one of which
2. The speed sensor device according to claim 1, wherein one of the moving yokes is attached to one end surface of the moving yoke, and the other one of the moving yokes is attached to the other end surface of the moving yoke. 3. At least one surface of the strip-shaped resistor,
The speed sensor device according to claim 1, wherein the speed sensor device is covered with an insulating film together with the first and second electrodes. 4. A strip-shaped resistor provided along a moving direction of a moving object and supported by a fixed base; and a strip-shaped resistor disposed facing one surface of the strip-shaped resistor and integrally with the moving object. A moving yoke that moves, the first and second output electrodes are provided along both widthwise end portions of the strip-shaped resistor, and the first and second output electrodes are provided at an intermediate position between the first and second output electrodes. A ground electrode is provided along each of the first and second output electrodes, a cross section orthogonal to the moving direction of the moving yoke is formed in a U shape, and one of the moving yokes formed in the U shape in cross section. The moving yoke is provided with a magnet of a predetermined size so that the other end surfaces of the moving yoke and the other end surface form different magnetic poles, and one end surface of the moving yoke faces the strip resistor located on the first output electrode side. And the other end of the moving yoke. Is provided so as to face the strip-shaped resistor located on the side of the second output electrode, and is equipped with signal adding means for adding the signals output from the first and second output electrodes and sending them to the outside. A speed sensor device characterized by the above. 5. A first and a second strip-shaped resistor, which are provided to face each other at a predetermined interval along a moving direction of a moving object and are supported on a fixed base, and to each facing surface of each of the strip-shaped resistors. Moving yokes that are arranged so as to face each other and move integrally with the moving object are provided, and first and second output electrodes are separately provided at both end portions in the width direction of the first and second strip-shaped resistors. And a ground electrode along the first and second output electrodes in an intermediate portion of the first and second strip resistors, respectively. A plurality of magnets are provided on both sides of the moving yoke so as to face the two surfaces separated by the ground electrode, and the plurality of magnets are provided as a whole through the fixed base, the band-shaped resistor and the moving yoke. The direction of each magnet to form one closed magnetic path A signal addition means is provided for taking out the electromotive force induced in the strip-shaped resistor with the movement of the moving yoke from each of the first and second output electrodes and adding and outputting them. Speed sensor device.