JPH0140926B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a position sensor that converts the displacement of a movable body into an electrical signal. Conventionally, some sensors of this type include a potentiometer with a slider connected to a movable body. In this case, the movable body moves according to external force,
An analog voltage corresponding to the amount of movement of the movable body is obtained from the potentiometer. In this type of position sensor, it is desired that the thin film resistor of the potentiometer has high wear resistance and that the output voltage level for the slider position is stable. It is desired that there is little play in the coupling mechanism, and that the contact between the slider and the thin film resistor is sufficiently stable against vibrations and shocks. However, since the slider and thin film resistor in the potentiometer are connected by pressure contact, wear, vibration, etc. will eventually cause an unstable output voltage with respect to fluid pressure. Further, one of the conventional sensors includes a sensor including a magnetic core, a winding wound around the magnetic core, and an oscillation circuit using the winding as a part. This type of sensor is known, for example, from Japanese Utility Model Publication No. 51-3018, which discloses a device for detecting the rotational position of a rotor;
They are disclosed in Japanese Patent Publication No. 65275, Japanese Patent Publication No. 43-9793 which discloses a position and movement measuring device, and Japanese Utility Model Publication No. 54-56990 which discloses a device that converts pressure into positional displacement. These sensors convert displacement into frequency by using the fact that the oscillation frequency of an oscillation circuit changes due to changes in the external magnetic field applied to the magnetic core. Sensors that utilize such frequency changes are
Since the detection result is output as a frequency, a frequency measuring device is required. In addition, at least 1/2 period from the starting point of oscillation (the point of transition from the H level to the L level or from the L level to the H level) is required for measurement to output the detection result. Therefore, at the start of measurement, there is a delay between the starting point and the starting point of oscillation. Furthermore, one of the conventional sensors is a sensor that converts a change in position into a change in magnetic field, and converts the change in magnetic field into a voltage using a coil. This kind of sensor is
Japanese Unexamined Patent Publication No. 52-21875 discloses a device that converts external pressure into a change in magnetic flux using a magnetostrictive element, Utility Model Registration No. 353311 discloses a device that detects temperature using displacement of a bimetal. 48−20481
This is disclosed in Japanese Patent Publication No. 46-23674, which discloses a device in which a magnet is displaced in accordance with pressure. A sensor that converts such a change in a magnetic field into a voltage outputs a voltage value, so it is vulnerable to electrical noise and has a large error. A first object of the present invention is to provide a position sensor equipped with a non-contact conversion means that does not have a mechanical contact mechanism in a mechanical-electrical conversion system that converts mechanical displacement into an electrical signal. A second object of the present invention is to provide a robust position sensor with high vibration and shock resistance. A third object of the present invention is to provide a position sensor in which electrical processing of a signal for detecting displacement of a movable body is relatively simple. A fourth object of the present invention is to provide a position sensor that can read displacement data of a movable body using relatively simple reading logic using an LSI such as a microcomputer, which has recently made remarkable progress. According to the present invention, one end of the movable body is connected to a permanent magnet, and the permanent magnet is displaced by the amount of movement (displacement) of the movable body. The position sensor detects this displacement using a soft magnetic material around which a coil 6 is wound, which is placed opposite to and in the vicinity of this permanent magnet, and converts it into an electrical signal. When a voltage is applied to a coil wound around a soft magnetic material, and the time taken from the voltage application start point until the soft magnetic material becomes magnetically saturated is T, approximately, T=N/E・(φm−φx) …(1 ) becomes. However, E: Voltage applied to the electric coil N: Number of turns of the electric coil φm: Maximum magnetic flux (≒ saturation magnetic flux) φx: Magnetic flux due to external magnetic field. Therefore, when φx changes due to movement of the permanent magnet, T changes. In other words, the permanent magnet is displaced according to the liquid pressure, and the external magnetic flux φx applied to the soft magnetic material changes accordingly, and the time T from when voltage is applied to the coil until the coil current reaches a predetermined level changes. Change. Therefore, the position sensor of the present invention is connected to an electric circuit or a semiconductor electronic device that measures T and represents it as an electric signal such as a voltage level or a digital code. In a preferred embodiment of the invention, the soft magnetic material is an amorphous magnetic material. Amorphous magnetic materials have to be made by rapidly cooling liquid phase metal, so they are thin plates.Moreover, they are magnetically ferromagnetic, have high magnetic permeability and saturation magnetization, have low coercive force, and mechanically have low fracture strength. It has extremely high elasticity and resilience. These characteristics of the amorphous magnetic material are extremely advantageous for the position sensor of the present invention, and its use has the advantage of simplifying and highly accurate signal processing in electrically measuring T, and mechanically This simplifies manufacturing and improves vibration and impact resistance. Other objects and features of the present invention will become clear in the following description of embodiments with reference to the drawings. In the embodiment shown in FIG. 1, a position sensor 1 has a permanent magnet 5 disposed in a housing 2 that abuts a connecting member 4 provided at one end of a movable body 3. When the movable body is displaced in the direction of the arrow, the permanent magnet is displaced to the left. At this time, an elastic spring 6 is provided to restore the permanent magnet to its original position (in the direction opposite to the arrow). In addition, a soft magnetic material 7 and a resin 8 for preventing deformation of the soft magnetic material are provided in parallel to the axial direction of the permanent magnet at a position facing the permanent magnet, and a coil 9 is provided on the outer peripheral surface of these materials. is wound. One end 9a of this coil
, one end 8a of the resin, and one end 10a of the terminal,
It is caulked and fixed with rivets 11.
At the other end, 9b, 8b, and 10b are similarly fixed with rivets. One end of the terminal is fixed by caulking, while the other end protrudes from the position sensor. In the position sensor constructed in this way, when the permanent magnet is forcibly displaced in the direction of the arrow as the movable body is displaced in the direction of the arrow in the figure, it is detected by the soft magnetic material around which the coil is wound, and an electrical signal is generated. It works by converting it into . At this time, the moving position of the permanent magnet 5 is detected by an electric processing circuit or a logic processing device. FIG. 2a shows one electrical processing circuit 100. FIG.
A constant level DC voltage (for example, +5V) is applied to a constant voltage power supply terminal 101 of the circuit 100.
A voltage pulse of, for example, 5 to 25 KHz is applied to the input terminal 102, and the NPN transistor 103 becomes conductive during the positive voltage section of the voltage pulse, and becomes non-conductive during the ground level. The PNP transistor 104 is on while the transistor 103 is on, and is off while the transistor 103 is off. Therefore, the electric coil 22 has an input terminal 1
A constant voltage (Vcc) is applied to the plastic level section of the voltage pulse applied to 02, and no voltage is applied to the ground level section. A voltage proportional to the current flowing through the coil 22 appears at the resistor 105, this voltage is integrated by an integrating circuit consisting of the resistor 106 and the capacitor 107, and the integrated voltage appears at the output terminal 108.
Figure 2b shows the input and output voltage waveforms of the circuit shown in Figure 2a. The time td from when the input voltage (IN) rises to a positive level until the voltage at resistor 105 rises above a certain level and the voltage at resistor 105 (a)
The integrated voltage Vx corresponds to the position of the magnet 15. 3a shows another electrical processing circuit 120. FIG. While the input voltage (IN) is at a positive level, NPN transistor 103 is on, PNP transistor 1
04 is turned on and voltage is applied to the coil 9.
While the input voltage (IN) is at ground level, the transistor 103 is turned off, the PNP transistor 104 is turned off, and no voltage is applied to the coil 9. The coil current is a junction type N-channel with constant current connection.
Flows to FET1 and FET2, FET1 and FET
2, the current value is controlled to a constant level. The level of current flowing through FET2 is set by variable resistor 122. The voltages at the coil terminals connected to FET1 and FET2 are amplified and waveform-shaped by inverting amplifiers IN1 and IN2. Figure 3b shows the input and output voltage waveforms of the circuit shown in Figure 3a. The output (OUT) of the circuit 120 is a voltage pulse that rises with a delay of td from the input pulse (IN), and this td corresponds to the position of the magnet 5. td is represented by a digital code in a counting circuit 140 shown in FIG. circuit 14
0, the flip-flop F1 is set at the rising edge of the input voltage (IN), and its Q output becomes high level "1", and the AND gate A1 is opened (on), and the pulses generated by the clock pulse oscillator 141 are counted by the counter 142. Applied to pulse input terminal CK. Output pulse (OUT) and F
A Q output of 1 is applied to the AND gate A2, and when the output pulse (OUT) rises, the AND gate A2 rises to a high level "1", and at the rising point, the flip-flop F1 is reset and its Q output becomes a low level "0". ”. This allows AND gate A1
The gate is closed (off), and the clock pulse to the counter 142 is cut off. And gate A2
When the output of the counter 142 becomes "1", the count code of the counter 142 is loaded into the latch 143.
Flip-flop F1 is reset and latch 1
After the count code is loaded into 43, AND gate A3 outputs a clock pulse to clear counter 142. The output code of latch 143 indicates the number of clock pulses generated during td, and this code indicates td. The electronic processing unit 160 shown in FIG. 5 includes a 1-chip microcomputer (large-scale integrated semiconductor device) 161, an amplifier 162, a junction type N-channel FET 1 for constant current control, a resistor 163, a capacitor 164, an amplifier 165, and a clock pulse oscillator 166. Consists of. The resistor 163 and the capacitor 164 constitute a filter that absorbs voltage vibrations at frequencies higher than the input and output pulse frequencies. The microcomputer 161 forms a pulse with a constant frequency within the range of 5 KHz to 30 KHz based on the clock pulse and supplies it to the amplifier 162.
On the other hand, the microcomputer 161 monitors the voltage at the connection point between the N-channel FET 1 and one end of the coil 22 (the output voltage of the amplifier 165), and from the rising point of the pulse outputted by itself to the rising point of the output voltage of the amplifier 165. Counts clock pulses during td and outputs a code indicating td (DATA OUT). As described above, the position sensor shown in FIG. 1 can connect various electrical processing circuits and logic processing electronic devices to obtain an electrical signal corresponding to the position of the permanent magnet 5 of the position sensor. Next, it will be explained that the position sensor 1 shown in FIG. 1 and the aforementioned electrical processing circuits 100, 120, 140 or logic processing device 160 can obtain electrical signals corresponding to the displacement of the movable body. First, due to the displacement of the movable body 3 of the position sensor 1, the permanent magnet 5 is displaced. Next, the conversion of the displacement of the permanent magnet 5 into an electric signal will be explained with reference to experimental data shown in FIGS. 6b to 6d. As shown in No. 6a, the inventor fixes the soft magnetic body 7, maintains the permanent magnet 5 parallel to it, and sets the axis passing through the center of the soft magnetic body 7 and orthogonal to its long axis as the X-X line. (Therefore, Y-Y is orthogonal to X-X), Vx and td for the Y-Y direction movement amount y of the permanent magnet 5, with the point where the center of the permanent magnet 5 is on the X-X line as the Y-Y axis origin
was measured. Dimensions a~ showing the shape and placement position
The correspondence between f, the material of the soft magnetic body, etc., and the measurement data is shown in Nos. 1 to 3 of Table 1 below.

【table】

[Table] *S-N in voltage application mode indicates that the coil 9 is connected to the electric circuit 100 or 120 so that the upper end of the soft magnetic material 7 becomes the S pole in Fig. 6a, and N-N indicates the soft magnetic material 7. It shows that the coil 9 is connected to the electric circuit 100 or 120 so that the upper end of the magnetic body becomes the north pole. In case No. 1, according to the data shown in Figure 6b, the distance in the Y-Y axis direction is from -5 mm to +9 mm, or from -6 mm to -20 mm, preferably from -3 mm to +
7mm or -8mm to -18mm, Y-
Highly accurate voltage for magnet movement amount y in the Y-axis direction
It can be seen that Vy can be obtained. In case No. 2, a voltage Vy with high precision can be obtained with respect to the magnet movement amount y over a wider range than in case No. 1. In case No. 3, the range of high linearity is relatively narrow, but it is distributed in various places with respect to y. Therefore, in the position sensor 1 shown in FIG.
The operating range of the magnet 5 is determined within a range where the linearity of Vy is high. 7a to 7d show other embodiments of the position sensor of the present invention, FIG. 7b is a plan view of FIG. 7a, and FIG. 7c is a B of FIG. 7b.
-B sectional view, and Figure 7d is A-A in Figure 7a.
FIG. In these drawings, a movable body 3 is fixed to the head of a permanent magnet 5, a soft magnetic body 7 is provided at one corner of the space inside the housing 2, and a soft magnetic body 7 is provided on the outer periphery of the body 3. A bobbin 20 is clamped, and a coil 9 is wound through this bobbin. Further, the end portion 20a of the bobbin is fixed together with one end of the coil and the end portion 10a of the terminal 10 by soldering. The longitudinal direction Y-Y axis of the soft magnetic body is perpendicular to the X-X axis in the moving direction of the movable body (arrow direction in Fig. 7a), and is parallel to the longitudinal direction Y'-Y' axis of the permanent magnet. located in parallel.
When the movable body 3 is displaced, the permanent magnet 5 is also displaced, which is detected by the soft magnetic material around which the coil is wound, and converted into an electrical signal. In this position sensor, the permanent magnet 5 moves toward the soft magnetic body 7 according to the displacement of the movable body.
It will move in the direction of the X-X axis in the figure. Experimental data in the mode of moving the permanent magnet 5 in this way are shown in Nos. 8a to 8f, and each data (Nos. 8a to 8f)
8f) and the correlations in shape, size, arrangement, etc. are shown in case Nos. 4 to 9 of Table 1. Chapters 8a-8
From the data in the f diagram, the permanent magnet 5 is
In the mode of driving in the X direction, the range (x) in which the linearity of the voltage Vx or the delay time td with respect to the moving amount x of the permanent magnet 5 is high is narrow. however,
Since the amount of change is large in a narrow range, the moving range of the permanent magnet 5 is set within that narrow range. The position sensor 1 shown in FIGS. 9a, 9b, 9c and 9d represents another embodiment of the invention. This position sensor 1 is the seventh
The structure is similar to that of the position sensor shown in a-7d, but a soft magnetic material sandwiched between bobbins whose outer circumferential surface is wound with a coil is placed in both corners of the space 21 in the housing 2. They are different in that they are arranged one each, two in total. The electrical processing circuit 180 shown in FIG.
It produces an analog voltage Vx responsive to the position of the permanent magnet 5 in the pressure sensor 1 shown in the figure. circuit 1
At 80, the NPN transistor 103 is turned on during the positive level of the input voltage pulse (IN), and turned off during the ground level. The collector voltage of transistor 103 is the same as that of two inverting amplifiers.
The signal is amplified and waveform-shaped through IN3 and IN4, and then applied to the base of the NPN transistor 121. Therefore, during the positive level of the input voltage pulse (IN), transistor 103 is on, 121 is off and PNP transistor 104 is off, and during ground level, transistor 103 is off, and when 121 is on, transistor 104 is on. In other words, a pulsed voltage is applied to the coil 9 in an operation similar to that of the circuit 120 in FIG. 3a, and the resistor 105
, a voltage pulse appears that corresponds to the distance x ₁ of the permanent magnet 5 from the soft magnetic body 7 and rises with a delay of td ₁ from the fall of the input voltage pulse (IN). A constant voltage is applied to the other electric coil 31 via a PNP transistor 181. This transistor 18
1, while the input voltage pulse (IN) is at a positive level, the transistor 103 is on and the inverting amplifier IN is turned on.
When the output of 5 is positive level, NPN transistor 1
Since 82 is on, it is on, and transistor 181 is off while the input voltage pulse (IN) is at ground level. As a result, a constant voltage is applied to the second electric coil 31 while no voltage is applied to the first electric coil 9, and no voltage is applied while the voltage is applied to the coil 9. That is, a constant voltage is alternately applied to the first and second coils 9 and 31 according to the input voltage pulse (IN). A resistor 183 is connected to the second electric coil 31, and a resistor 183 is connected to the resistor at a delay of td ₂ from the rise of the input voltage pulse (IN) corresponding to the distance x ₂ of the permanent magnet 5 from the soft magnetic material 29. A rising voltage pulse appears. The voltage Vx ₁ across the resistor 105 is applied to one electrode of the capacitor 184;
A voltage Vx ₂ of 3 is applied to the other electrode of the capacitor 184. The distances between the permanent magnet 5 and the first and second soft magnetic bodies 7 and 29 are x ₁ and x ₂ , respectively.
And since x ₁ + x ₂ = K (constant), also,
Since Vx ₁ ∝x ₁ and Vx ₂ ∝x ₂ , the potential difference across capacitor 184 corresponds to x ₁ −x ₂ . Since the capacitor 184 and the resistor 185 constitute an integrating circuit, the voltage of the capacitor 184 is x ₁ - x ₂
corresponds to Here, since x ₂ = K−x ₁ , x ₁
−x ₂ = 2x ₁ +K, and the voltage on capacitor 184 is 2x ₁
corresponds to In other words, an analog voltage corresponding to twice the amount of movement x ₁ of the permanent magnet 5 from the first soft magnetic body 7 is obtained. Both ends of capacitor 184 are applied to operational amplifier 186 in a differential amplification setting. The analog output Vx of amplifier 186 thus corresponds to _2x1 . The electrical processing circuit 200 shown in FIG. 10b obtains pulses delayed by td ₁ and td ₂ from the rising edges of the input pulses of the two circuits 120, respectively, and these pulses are applied to each of the two counting circuits 140, and the pulses are applied to each of the two counting circuits ₁₄₀ . and code S indicating td ₂
18 and S29 and applied to the subtracter 201. The subtracter 201 uses S7 and S29 to
Subtract td ₁ −td ₂ and output a digital code Sx=S7−S29 representing td ₁ −td ₂ , that is, 2x1. 1st
In the logic processing electronic device 220 shown in FIG.
Create and hold td ₁ count data S7, then give one pulse to the circuit 120 connected to the electric coil 31, start time counting from the rising edge of the pulse, create td ₂ count data S29, and then td ₁ −td ₂
is calculated and outputs the code Sx=S7-S29 indicating it, and this operation is continued while the measurement finger cooling signal is given. As shown in FIG. 11a, the inventor fixed the soft magnetic bodies 7 and 29 parallel to each other, and placed the permanent magnet 5 between them to make the magnet 5 parallel to the soft magnetic bodies 7 and 29. And when the center of the permanent magnet 5 is aligned with the X-X axis with the axis passing through their centers orthogonal to their long axes being the X-X axis, and the magnet 5 is located between the soft magnetic bodies 7 and 29, is at the origin of the X-X axis (x=0), and the X-X of the permanent magnet 5 is
Vx with respect to the amount of movement x in the direction was measured. The following Table 2 shows the correspondence between dimensions a to f indicating the shape and arrangement, the material of the soft magnetic body, etc., and the measurement data.

[Table] When the distance f between the soft magnetic bodies 7 and 29 is short,
As shown in FIGS. 11b and 11c, -
In the range of 10 mm<x<10 mm, an x vs. Vx characteristic with high linearity with respect to x can be obtained. When the distance f between the soft magnetic bodies 7 and 29 is long, S-
In the N mode, linearity is relatively good in the range -9 mm < x < 9 mm, but the range of good linearity is narrower than when f is short, and the linearity is also worse than when f is short. Furthermore, as shown in Figure 11e, in the N-N mode, the linearity is very poor near the origin (x=0), but rather the linearity is good in the range near the origin (x=0) to one of the soft magnetic bodies. Therefore, the characteristics approach those of case Nos. 4 to 9. This is because the magnetic field exerted by the permanent magnet 5 on the soft magnetic bodies 7 and 29 is weak when it is near the origin. Therefore, the x-Vx characteristics change not only depending on the distance f between the soft magnetic bodies 7 and 29, but also on the shape of the permanent magnet 5 and the strength of the generated magnetic field.
The x-Vx characteristics can be selected relatively easily as desired. All of the embodiments described above are configured to detect the displacement of the movable body. Furthermore, in any of the above embodiments, the soft magnetic bodies 7 and 29 have high magnetic permeability, high elasticity,
Although it is made by stacking several sheets of amorphous magnetic material that is difficult to deform, according to the present invention, soft magnetic materials 7 and 2
As 9, other magnetic materials can be used. FIG. 13 shows x-Vx measurement data for other magnetic materials and an amorphous magnetic material. These are arranged so that the soft magnetic material and the permanent magnet are arranged in the manner shown in Fig. 6a, and the permanent magnet is
The shape and arrangement of each soft magnetic body are obtained by moving it in the
Shown below. If you look at the carps A1 to C2 in Figure 13,
For any soft magnetic material, the range is at least 6 mm (for example, for A1, from x = 10 mm to x = 16 mm,
For B1, x-Vx (from x=8mm to x=14mm)
The curves exhibit high linearity, and both can be used in the position sensor of the present invention. In applications requiring high vibration resistance and deformation resistance, it is preferable to use an amorphous magnetic material. As can be understood from the description with reference to the several embodiments and experimental data above, the position sensor of the present invention does not have a sliding contact and uses an electric coil to detect the displacement of a permanent magnet corresponding to the displacement of a movable body. Since the displacement detection signal of the movable body is obtained by electrical processing of converting the time difference between the input pulse and the current pulse of the electric coil to td, and obtaining td using an analog voltage or time count code, it has high vibration resistance and is mechanically There is little deterioration such as wear. Since there is no coupling mechanism between the movable body and the transducer, displacement of the movable body can be stably detected without causing play. What is noteworthy is that the configuration of the electrical processing circuit connected to the sensor is simple. In particular, a large-scale semiconductor device such as a one-chip microcomputer is used to create a displacement detection pulse for the movable body, and the pulse is combined with the electric coil. This means that the time difference between the energizing current detection pulses can be easily obtained using a digital code.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a position sensor 1 according to an embodiment of the present invention; FIG. 2a is an electrical processing circuit connected to the position sensor 1 shown in FIG. 1 and generating an analog voltage at a level corresponding to the detected pressure. 100; FIG. 2b is a waveform diagram showing input and output signals of the electrical processing circuit 100 shown in FIG. 2a; FIG. 3a is a waveform diagram showing input and output signals of the electric processing circuit 100 shown in FIG.
The figure is a circuit diagram showing an electric circuit 120 connected to the position sensor 1 shown in Fig. 1 and generating pulses with a time difference corresponding to the detected pressure; Fig. 3b is a circuit diagram showing the input and output of the electric processing circuit 120 shown in Fig. 3a. Waveform diagram showing signals; Figure 4 is the electrical processing circuit 1 shown in Figure 3a.
A block diagram showing a counting circuit 140 that converts the input and output pulse time difference td of 20 into a digital code; A block diagram showing an electronic processing unit 160 that counts the delay time of the rise of the current flowing through the electric coil 9 with respect to the pulse voltage applied to the coil 9; FIG. 6a shows the pulse time difference corresponding to the position of the permanent magnet 5 with respect to the soft magnetic body 7. A perspective view showing the relative positional relationship between the soft magnetic material 7 and the permanent magnet 5 when td is experimentally determined; FIG. 6b shows the permanent magnet 5 moved in the Y-Y direction in the arrangement shown in FIG. The electric processing circuit 100 shown in FIG. 2a is connected to the electric coil 9, and the Y of the permanent magnet 5 with a length of 10 mm is connected.
- Time difference td display voltage for movement amount y in the Y direction
Graph showing the data of measuring Vy - The pulse voltage applied to the electric coil 9 was set to the polarity that magnetized the upper end of the soft magnetic body 7 to the S pole in Fig. 6a -; Fig. 6c is as shown in Fig. 6b. The corresponding y-Vy measurement curve shows the measurement data using a permanent magnet of length 30 mm; Figure 6d is the y-Vy measurement curve corresponding to Figure 6b.
- This is a Vy measurement curve, showing measurement data using a permanent magnet with a length of 30 mm. - The pulse voltage applied to the electric coil 9 has a polarity that magnetizes the upper end of the soft magnetic body 7 to the north pole in Fig. 6a. It was said that -; 7th
Fig. 7a is a longitudinal sectional view showing another position sensor of the present invention; Fig. 7b is a plan view of the position sensor shown in Fig. 7a; Fig. 7c is a sectional view taken along line BB in Fig. 7b; Figure 7d is a sectional view taken along the line A-A in Figure 7a; Figure 8a shows the permanent magnet 5 moved in the X-X direction in the arrangement shown in Figure 6a, and the electric coil 9 subjected to the electrical treatment shown in Figure 2a. Connect the circuit 100,
A graph showing measurement data of the time difference display voltage Vx with respect to the moving amount x of the permanent magnet 5 with a length of 10 mm in the X-X direction. 8b, the permanent magnet 5 is moved in the X-X direction in the arrangement shown in FIG. 6a, and the electric coil 9 is connected to the electric processing circuit 120 shown in FIG. 3a. A graph showing the data obtained by connecting the input and output pulse waveforms with a synchroscope and measuring the time difference td between the two. - Electric coil 9
The pulse voltage applied to is set to have a polarity that magnetizes the upper end of the soft magnetic body 7 to the S pole in FIG. 6a.
FIG. 8c is an x-Vx measurement curve corresponding to FIG. 8a, and the pulse voltage applied to the electric coil 9 was set to have a polarity that magnetized the upper end of the soft magnetic body 7 to the north pole in FIG. 6a; Figure 8d is an x-td measurement curve corresponding to Figure 8b, and the pulse voltage applied to the electric coil 9 was set to have a polarity that magnetized the upper end of the soft magnetic body 18 to the north pole in Figure 6a; The figure is the x-Vx measurement curve corresponding to figure 8a, a permanent magnet with a length of 30 mm was used;
Figure f is an x-td measurement curve corresponding to Figure 8b, in which a permanent magnet with a length of 30 mm was used; Figure 9a is a longitudinal cross-sectional view showing yet another position sensor of the present invention; Figure 9b is a plan view of the position sensor shown in Figure 9a; Figure 9c is a sectional view taken along line B-B in Figure 9b; Figure 9d is a sectional view taken along line A-A in Figure 9a; Figure 10a is a cross-sectional view taken along line 9 of Figure 9a; A circuit diagram showing an electric processing circuit 180 that is connected to the position sensor 1 shown in the figure and generates an analog voltage at a level corresponding to the detected pressure; FIG. A block diagram showing the configuration of an electric processing circuit 200 that generates a digital code corresponding to the detected pressure; FIG. 10c shows the configuration of a logic processing electronic device 220 connected to the position sensor 1 shown in FIG. FIG. 11a is a block diagram showing the difference in delay time of each electric coil 9, 31 corresponding to the position of the permanent magnet 5 with respect to the soft magnetic bodies 7, 29, which is obtained by experiment.
A perspective view showing the relative positional relationship between the soft magnetic bodies 7, 29 and the permanent magnet 5; Fig. 11b shows the distance between the electric coils 9, 31 by moving the permanent magnet 5 in the X-X direction in the arrangement shown in Fig. 11a. 35mm, coil 9, 31
is a graph showing data obtained by connecting the electric processing circuit 180 shown in FIG. , 31 has a polarity that magnetizes the upper ends of the soft magnetic bodies 7, 29 to S poles in FIG. 11a;
FIG. 11c is an x-Vx measurement curve corresponding to FIG. 11c, and the pulse voltage applied to the electric coils 9, 31 is
11th
Figure 11e is an x-Vx measurement curve corresponding to Figure 11c, with the distance between coils 9 and 31 being 50 mm; The distance between them was 50 mm; Fig. 12 shows the permanent magnet displacement x in the X-X direction of various soft magnetic materials in the arrangement shown in Fig. 6a, and the measured value using the electric processing circuit 100 shown in Fig. a. It is a graph showing correlation. 1: Position sensor, 2: Casing,
3: Movable body, 5: Permanent magnet, 7: Soft magnetic body, 9:
Electric coil, 10: terminal, 20: bobbin,
29: Soft magnetic material, 31: Electric coil, 100: Electrical processing circuit, 101: Constant voltage power supply terminal, 102:
Input terminal, 103: NPN transistor, 10
4: PNP transistor, 105, 106: resistor,
107: Capacitor, 108: Output terminal, 12
0: Electric processing circuit, 121: NPN transistor,
122: Variable resistance, FET1, FET2: Junction type N
Channel field effect transistor, IN1, IN
2: Inverting amplifier, 140: Counting circuit, 141: Clock pulse oscillator, 142: Counter, 14
3: Latch, F1: Flip-flop, A1-A
3: AND gate, 160: Electronic processing unit,
161:1 chip microcomputer, 16
2: Amplifier, 163: Resistor, 164: Capacitor, 165: Amplifier, 166: Clock pulse oscillator, 180: Electrical processing circuit, IN3 to IN5: Inverting amplifier, 181: PNP transistor, 18
2: NPN transistor, 183: Resistor, 18
4: Capacitor, 185: Resistor, 186: Operational amplifier, 200: Electrical processing circuit, 201: Subtractor,
220: Logic processing electronics, 221: 1 chip microcomputer.

Claims (1)

[Claims] 1. A movable body; A permanent magnet connected to the movable body; Soft magnetic core means disposed near the moving range of the permanent magnet; Wound around the soft magnetic core means. an electric coil means; a voltage generating means; a voltage switching means for applying a voltage generated by the voltage generating means to the electric coil means in accordance with an instruction; and a current detecting means for detecting a current flowing through the electric coil means; A position sensor whose output value is the time from the instruction to the saturation of the measurement current of the current detection means.