JP2000161985A - Noncontact-type position sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noncontact-type position sensor, capable of obtaining stable operation to displacements of the location of a shaft interlocked with a body to be detected. SOLUTION: A metal shaft 2 is inserted into a sensor coil part 1, in such a way as to be freely movable linearly. The sensor coil part 1 and a capacitor in a sensor circuit 3 constitute a parallel resonance circuit, and its oscillation is driven for generating high-frequency modulated magnetic field. By inserting the metal shaft 2 into the sensor coil part 1, magnetic flux is passed through the metal shaft 2 to increase the magnetic resistance of a system, and an eddy current loss occurs on the surface of the metal. As a result of this, what was a constant energy state is changed. Such a change occurs continuously accompanying the continuous linear movements of the metal shaft 2 without singular points or extreme values, and a voltage signal corresponding to the amount of movements of the metal shaft 2 is outputted from the sensor circuit 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact position sensor for an automobile used as an AT position sensor or a neutral sensor used for an automobile transmission.

[0002]

2. Description of the Related Art In general, various positions of an automatic transmission of a vehicle [parking (P), reverse (R), neutral (N), drive (D), 3rd (3), 2nd (2), Low ( 1)]
For the purpose of checking the change in the gear position, a mechanism for converting the rotation angle of the rotation shaft of the AT switch by a mechanical mechanism linked to the transmission gear is provided, and the AT switch outputs a code pattern corresponding to the gear position.

As shown in FIG. 20, the basic structure of an AT switch is provided with movable contacts 103 to 106 on a movable piece 101 which rotates in conjunction with rotation of a built-in rotary shaft 100, and fixed contacts 107 to 106 are fixed on a fixed base 102. 110 is provided, and the movable contact and the fixed contact perform a contact / non-contact operation for each garbage, thereby connecting / non-contacting an electric circuit, and outputting outputs of four channels corresponding to each of the movable contacts 103 to 106. It is a switch to get. These outputs are input to a vehicle arithmetic and control unit (ECU) 111. The vehicle arithmetic and control unit 111 determines the gear position based on the code patterns of these outputs and performs control according to the position.
For example, in the reverse position (R), the backlight 1
Turn on 12 and parking position (P)
And ignition 11 in neutral position (N)
3 is operable. In the state of FIG. 20, the movable contact 103 and the fixed contact 107 are in non-contact at the D position, the output of the channel L4 is "H", and the movable contact 104 and the fixed contact 108 are in contact and the output of the channel L3 is "
L ”, the output of the channel L2 is“ H ”because the movable contact 105 and the fixed contact 109 are not in contact, and the output of the channel L1 is“ L ”because the movable contact 106 and the fixed contact 110 are in contact. A current flows through the backlight 112 and the ignition 113 depending on the contact pattern of the contacts.

[0004] In the case of the above-mentioned conventional example, the life of the contact basically becomes a problem. Therefore, grease is used to protect the contact points and prevent corrosion due to moisture. This grease is given a role to withstand severe use environment and to guarantee a long service life. However, in reality, in a cold region of Europe and North America, there are problems such as grease being hardened in winter and the switch not operating and poor contact. Therefore, a contactless type having basically no contact has been desired.

Although the position of a mission can be logically monitored, a change between the positions of the mission cannot be continuously monitored. Therefore, for continuously variable transmission such as CVT which has been put into practical use in recent years, it is necessary to continuously monitor the position of the mission.

[0006] Even in the conventional mission system,
The demand for controlling the drive system at an arbitrary timing before the position changes (the purpose of smoother shifting than before) has increased, and the conventional position position is output by turning on / off a plurality of contacts. AT switches have become unsatisfactory in performance.

In order to make the contactless, a method using a sensor such as an application of a rotary encoder using light or an application of a magnetic switch can be considered, but there are many problems in use in a vehicle environment. That is, temperature, vibration, dirt on the lens and the like become problems.

A non-contact type AT position sensor is disclosed in Japanese Utility Model Registration No. 2574099. The feature of this conventional example is that a permanent magnet 201 is provided on a shaft 200 as shown in FIG.
As the 00 moves, the magnetic flux linked to the Hall element 202 changes. The point is that the position change is converted into a continuous signal by detecting this. However, this conventional example has the following problems.

(1) It is unstable with respect to the displacement of the shaft 200, and the change with time in long-term use cannot be expected.
In addition, there is no method for suppressing individual variations in characteristics.

(2) When the slide amount is increased, the magnetic flux density decreases exponentially, and there is no linearity. Therefore, it cannot cope with a case where the movement amount of the shaft 200 is large.

(3) There is a concern that the characteristics of the magnet vary and the characteristics change over time.

(4) It is difficult to attach the position sensor so that the shaft 200 is accurately drawn into the body of the position sensor, and the predetermined performance is not obtained.

(5) Also affected by the material of the shaft 200.

(6) Hall element 20 as sensor element
2 requires the signal amplifier to be close to the
Is common. Therefore, it is not possible to install only the sensor element in a narrow part and to install the signal processing in a free place.

[0015]

In addition to the above-mentioned problems of the prior art, after the non-contact can be performed, the problem is that
Irrespective of the detection method, the non-linearity of the detection signal is improved. This can be corrected by a vehicle arithmetic and control unit (ECU) on the control side. However, considering S / N degradation during transmission, it is preferable that linear correction can be performed when a sensor is detected. In the graph of FIG. 22, in the case of a non-linear signal, the resolution of the positions (1) to (D) is small, and it becomes indistinguishable due to noise contamination. The vertical axis in FIG. 22 indicates the voltage level of the detection signal.

On the other hand, a linear linear signal does not have a problem like a nonlinear signal. The actual non-linearity is because the rate of change of the magnetic field that changes with the movement of the metal shaft is not proportional to the movement distance. The cause is due to leakage of magnetic flux or mutual induction of transformer coupling. Therefore, it is considered that the detection signal does not have a singular point and basically has no extreme value. Therefore, it is expected that the nonlinear signal can be approximated by a linear equation of several orders, and that the correction can be similarly approximated by a linear equation of several orders.

Next, stabilization of temperature characteristic changes and variations which are problematic in the actual use state of the sensor is indispensable especially for control using the detection signal itself.

Although it is possible to make corrections on the side of the vehicle arithmetic and control unit (ECU), in order to correct all sensor variations and temperature changes, the signal allowable range (dynamic range) on the vehicle side of the arithmetic and control unit (ECU) is required. ) Requires a sufficient margin.

Conversely, if a sufficient margin is provided, the resolution is sacrificed, and the accuracy of the system is reduced. Therefore, correction by the sensor is required.

The present invention has been made in view of the above points, and has as its object to provide a non-contact type position sensor capable of obtaining a stable operation with respect to a position shift of a shaft interlocked with an object to be detected. To provide.

At the same time, it is advantageous for linearity stability, and can reduce the influence of the absolute variation of the components. Further, it is not affected by the material of the metal shaft of the object to be detected. The linearity can be stabilized even if the amount of movement of the sensor increases, and a stable output signal can be obtained even when the temperature varies, and the stability of the change in the transmission ratio can be improved. It is an object to provide a contactless position system that can be installed.

[0022]

According to a first aspect of the present invention, there is provided a sensor coil unit comprising one or a plurality of coils and a linear motion sensor in a high-frequency magnetic field generated from the coil of the sensor coil unit. It is characterized by comprising a metal shaft arbitrarily arranged and linked to the movement of the object to be detected, and a sensor circuit for extracting a magnetic field change amount that changes according to a positional relationship between the sensor coil unit and the shaft by a continuous signal. .

According to a second aspect of the present invention, in the first aspect of the present invention, the sensor circuit includes an oscillating circuit for generating a high-frequency magnetic field in the coil of the sensor coil section, and a coil and a shaft of the sensor coil section for generating the high-frequency magnetic field. A detection circuit that detects a change in the oscillation state of the oscillation circuit due to a positional relationship, a detection amplification circuit that detects and amplifies a detection signal of the detection circuit, and a filter that cuts an unnecessary frequency band from an output signal from the detection amplification circuit And an output buffer circuit for reducing the impedance of the output signal of the filter circuit and outputting the output signal, wherein the output signal voltage and the moving distance of the shaft have a proportional relationship.

According to a third aspect of the present invention, there is provided an exciting coil for generating a high-frequency magnetic field, a sensor coil portion in which the exciting coil is double-wound and both coils are transformer-coupled, and an inner coil of the sensor coil portion. A metal shaft that is linearly movable in the central through-hole, and a sensor that extracts the amount of change in the transformer coupling state that changes according to the positional relationship between the sensor coil and the shaft with a continuous signal, in conjunction with the movement of the object to be detected. And a circuit.

According to a fourth aspect of the present invention, there is provided a sensor coil section having an exciting coil for generating a high-frequency magnetic field, and a detecting coil which is disposed in such a way that the exciting coil is coaxially and linearly connected and is transformer-coupled. , A metal shaft that is arranged to be able to move directly in the center through holes of both coils of the sensor coil part, and that changes in the transformer coupling state that changes according to the positional relationship between the sensor coil part and the shaft in conjunction with the movement of the detected object A sensor circuit for extracting the quantity as a continuous signal.

According to a fifth aspect of the present invention, there is provided a sensor coil unit having an excitation coil for generating a high-frequency magnetic field, which is arranged with a predetermined gap in the same axial direction, and a detection coil transformer-coupled to the coil. A metal shaft that is disposed in a gap between the two coils of the sensor coil unit so as to be able to move linearly in a direction perpendicular to the axial direction of the two coils, and that interlocks with the movement of the object to be detected; And a sensor circuit for extracting the amount of change in the transformer coupling state that changes with the positional relationship as a continuous signal.

According to the sixth aspect of the present invention, a sensor coil unit including an excitation coil and a detection coil for generating a high-frequency magnetic field, and one of the detection coil and the excitation coil is connected to a sensor coil unit. A shaft wound around the shaft and arranged in a central through-hole of the other coil so as to be able to linearly move together with the one coil, and a change in a transformer coupling state that changes due to a positional relationship between the two coils of the sensor coil portion due to movement of the shaft A sensor circuit for extracting the quantity as a continuous signal.

According to a seventh aspect of the present invention, in any one of the third to sixth aspects of the present invention, the sensor circuit includes: an oscillation circuit for generating a high-frequency magnetic field in an exciting coil of the sensor coil unit; A detection circuit that detects a change in state from the output of the detection coil, a detection amplification circuit that detects and amplifies the detection signal of the detection circuit, and a filter circuit that cuts unnecessary frequency ranges from the output signal from the detection amplification circuit. And an output buffer circuit for outputting the output signal of the filter circuit with a low impedance and outputting the output signal, wherein the output signal voltage and the moving distance of the shaft have a proportional relationship.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects of the present invention, the shaft is a metal shaft which directly moves an object to be detected. Claim 1
8. The non-contact position sensor according to any one of items 7 to 7.

According to a ninth aspect of the present invention, in any one of the first to seventh aspects of the present invention, the shaft is linearly connected to a metal shaft, which is provided outside the sensor coil portion and directly moves the object to be detected. At least a separate metal body interlocking with the direct movement of the metal shaft, and the distance between the circumferential surface of the metal body and the inner circumferential surface of the coil of the sensor coil unit facing the metal body is kept constant. I do.

According to a tenth aspect of the present invention, in the ninth aspect of the present invention, the metal body is formed by performing linear correction by shape processing.

According to an eleventh aspect of the present invention, in any one of the first to seventh aspects of the present invention, the shaft is an arm fixed to a metal shaft, which is provided outside the sensor coil portion and moves directly on the object to be detected. At least a separate metal body connected in parallel with the linear motion of the metal shaft and connected with the metal shaft, while maintaining a constant distance between the circumferential surface of the metal body and the inner circumferential surface of the coil of the sensor coil unit facing the same. It is characterized by comprising.

According to a twelfth aspect of the present invention, in any one of the first to eleventh aspects, a reference coil unit having the same characteristics as the sensor coil unit is provided in parallel, and an output from the reference coil unit is provided in the sensor circuit. Means is provided for controlling the operation of generating a magnetic field in the coil of the sensor coil unit so as to amplify the difference between the signal voltage and the reference voltage so that the output voltage signal of the reference coil unit becomes constant.

According to a thirteenth aspect of the present invention, in any one of the first to twelfth aspects, the sensor circuit is provided at a position separated from the sensor coil portion by a coil wire derived from the sensor coil portion. And

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

(Embodiment 1) FIG. 1 shows the configuration of the present embodiment. As shown in the figure, in this embodiment, a sensor coil unit 1 which is a fixed pickup unit is a single coil 1.
The metal shaft 2 of the transmission, which is the object to be detected, is inserted into the center through hole of the coil 10 so as to be able to move linearly. The coil 10 is connected to the sensor circuit 3 having the configuration shown in FIG.

The coil 10 forms a parallel resonance circuit with the capacitor C1 and generates a high-frequency modulation magnetic field by being excited by the oscillation circuit 30, and the magnetic flux generated by the magnetic field links the metal shaft 2. .

Here, when the metal shaft 2 is not inserted into the coil 10, the impedance of the coil 10
It is a composite value of the magnetic resistance, inductance, and winding resistance of the coil 10 itself. In this state, when oscillation occurs in the resonance circuit of the coil 10 and the capacitor C1, a state is maintained in which a constant energy is maintained.

When the metal shaft 2 is inserted into the coil 10, magnetic flux passes through the metal shaft 2, so that the magnetic resistance of the system increases and eddy current loss occurs on the metal surface. I do. As a result, what has been in a constant energy state changes, and a stable balance state is maintained with the metal shaft 2 inserted into the coil 10.

Such a change occurs continuously without a singular point or an extremum in accordance with the continuous linear movement of the metal shaft 2.

The oscillation signal of the parallel resonance circuit including the coil 10 and the capacitor C1 is input to the detection circuit 31. The amplitude of the oscillation signal input to the detection circuit 31 changes due to the back electromotive force caused by the eddy current when the peripheral surface of the metal shaft 2 faces the inner peripheral surface of the coil 10 that generates the high-frequency modulated magnetic field. , A signal including a change in the oscillation amplitude according to the movement (presence or absence) of the metal shaft 2.
The small signal detected and output by the detection circuit 31 is cut off in the original oscillation frequency by the detection amplification circuit 32, and is amplified and converted into a change in the DC voltage due to the movement (presence or absence) of the metal shaft 2. However, strictly speaking, the DC signal has an oscillation circuit 3
The ripple of the oscillation frequency component of 0 remains. The filter circuit 33 removes unnecessary frequency ranges such as the ripple and external noise in accordance with the use of the responsiveness of the system to obtain a stable DC voltage. The output buffer circuit 34 lowers the impedance of the DC voltage signal output from the filter circuit 33 and outputs the signal to the vehicle control circuit (ECU) 4. The vehicle control circuit 4 determines the gear position of the transmission based on the voltage level of the DC voltage signal,
For example, in the case of the reverse position (R), the backlight 5 is turned on, and in the parking position (P) and the neutral position (N), the ignition 6 is operable.

FIG. 3 shows the relationship between the moving distance D of the metal shaft 2 and the output signal voltage Vs (= f (D)) of the sensor circuit 3. The output signal voltage Vs is a continuous signal proportional to the moving distance D. It will be obtained as a typical signal.

In FIG. 2, the detection circuit 31 is constituted by an independent circuit. However, as shown in FIG. 4, the detection circuit may be used also as an oscillation circuit.

(Embodiment 2) In the present embodiment, as shown in FIG. 5, the sensor coil unit 1 is composed of a primary coil 11 in which the sensor coil unit 1 is concentrically arranged in two layers, and a secondary coil 12. The metal shaft 2 is inserted in the center through hole of the primary coil 11 inserted therein so as to be able to move linearly. The primary coil 11 and the secondary coil 12 are transformer-coupled (magnetically coupled), and a continuous signal is obtained from the secondary coil 12 based on a change in the transformer coupling (magnetic coupling) state that changes depending on the positional relationship of the metal shaft 2.

FIGS. 6A and 6B are a side sectional view and a front sectional view of the sensor coil unit 1. As shown, the sensor coil unit 1 has a primary shape in a case 13 having a cylindrical outer shape. A secondary coil 12 is provided on an outer layer of the coil 11 with an insulator 14 interposed therebetween.
It is configured to house the double coil wound
The metal shaft 2 is inserted into the center through hole of the primary coil 11 from the outside so as to be able to move linearly through a circular hole 15 opened at the center of one end surface of the case 13.

The sensor circuit 3 may be built in the sensor coil unit 1 or may be configured as a separate component. The circuit configuration is as shown in FIG. In the present embodiment (embodiments 3 and 4 described later), the primary coil 11
And a capacitor C1 connected in parallel to form a resonance circuit,
The primary coil 11 is excited by the oscillation circuit 30 to generate a high-frequency modulation magnetic field. That is, the primary coil 11 forms an excitation coil. On the other hand, the primary coil 11
The secondary coil 12 which is transformer-coupled (magnetically coupled) is connected to a detection circuit 31 and a magnetic field change amount (inductance of the coil, which varies depending on the positional relationship of the metal shaft 2 which moves directly in the center through hole of the primary coil 11). A signal (voltage, current) corresponding to the impedance and the resonance frequency is output to the detection circuit 31 as a continuous signal. That is, the secondary coil 12 forms a detection coil.

Specifically, in the present embodiment, the primary coil 1
The transfer characteristic of the high-frequency magnetic field generated in step 1 to the secondary coil 12 is represented by a change in magnetic resistance due to the movement of the metal shaft 2,
The voltage is changed by a back electromotive force (eddy current effect) due to an eddy current generated on the metal surface, and a voltage signal having an amplitude change due to the change is output from the secondary coil 12. Of course, in addition to the amplitude change, a frequency change and an impedance change may be detected. The small signal output from the detection circuit 31 has its original oscillation frequency cut by the detection amplification circuit 32 and is amplified and converted into a change in DC voltage of a predetermined magnitude.
The ripple of the oscillation frequency component of the oscillation circuit 30 remains in this DC signal. The filter circuit 33 removes unnecessary frequency ranges such as the ripple and external noise according to the system responsiveness specification in the same manner as the circuit of the first embodiment, thereby obtaining a stable DC voltage. The output buffer circuit 34 lowers the impedance of the DC voltage signal output from the filter circuit 33 and outputs the signal to the vehicle control circuit (ECU) 4. The vehicle control circuit 4 determines the gear position of the transmission based on the voltage level of the DC voltage signal,
For example, in the case of the reverse position (R), the backlight 5 is turned on, and in the parking position (P) and the neutral position (N), the ignition 6 is operable.

FIG. 8 shows the relationship between the output signal voltage Vs (= f (X)) of the sensor circuit 1 of the present embodiment and the moving distance X of the metal shaft 2. The output signal voltage Vs is equal to the moving distance X. It will be obtained as a proportional and continuous signal.

(Embodiment 3) In Embodiment 2 described above, the sensor coil unit 1 is constituted by a double coil in which the primary coil 11 and the secondary coil 12 are concentrically arranged. Primary coil 11 and secondary coil 12
And a metal shaft 2 is inserted into the central through-holes of the coils 11 and 12 so as to be able to move linearly.
The transformers 1 and 12 are transformer-coupled (magnetically coupled) as in the second embodiment, and the transformer coupling (magnetic coupling) state of the primary coil 11 and the secondary coil 12 changes due to a change in the positional relationship due to the movement of the metal shaft 2. , A continuous signal corresponding to the change is detected from the secondary coil 12.

In this embodiment, the same operation as in the first and second embodiments is performed by using the circuit shown in FIG. 7 as the sensor circuit 3, and the metal shaft 2 shown in FIG. The output signal of the voltage proportional to the moving distance X of the above is obtained. Note that the description of the operation of the present embodiment using FIG. 7 refers to the description of the second embodiment, and a description thereof will be omitted.

In this embodiment configured as described above,
The turns ratio between the primary coil 11 and the secondary coil 12 can be set without restriction. In addition, two coils of the same specification are connected in series, one of which is a primary coil 11 and the other is a secondary coil 12.
Parts can be shared.

Further, the amount of movement of the metal shaft 2 can be increased, and the sensitivity to the movement of the metal shaft 2 can be increased as compared with the second embodiment.

(Embodiment 4) In Embodiments 2 and 3, the metal shaft 2 is inserted in the center through hole of the coil so as to be able to move directly. However, in this embodiment, as shown in FIG. 1, a primary coil 11 and a secondary coil 12 are coaxially arranged at a constant interval, and the primary coil 11
And a sensor coil unit 1 having a structure in which a metal shaft 2 is disposed between a secondary coil 12 and a metal shaft 2 so as to be able to linearly move in a direction orthogonal to the axial direction of the two coils 11, 12.
A continuous signal corresponding to a transformer coupling (magnetic coupling) state that changes according to the positional relationship between the secondary coil 11, the secondary coil 12, and the metal shaft 2 is obtained from the secondary coil 12.

That is, the high-frequency magnetic field generated by the primary coil 11 changes depending on the positional relationship between the two coils 11, 12 and the metal shaft 2, and the amount of change in the magnetic field (coil inductance, impedance, resonance frequency) Is obtained as a continuous signal (voltage, current).

FIGS. 11 (a) and 11 (b) show a side sectional view and a horizontal sectional view of the sensor coil unit 1. A space for inserting the shaft 20 is provided at the center of the resin case 13. As shown, the coil housing 1
6a and 16b are formed, and the primary coils 11 and 12 are stored in the coil storage portions 16a and 16b, respectively, and the round hole 1 is opened on the side surface of the case 13 so as to communicate with the space.
5, the metal shaft 2 is inserted so as to freely move.

In this embodiment, the same operation as in the first and second embodiments is performed by using the circuit of FIG. 7 as the sensor circuit 3, and the metal shaft 2 shown in FIG. The output signal of the voltage proportional to the moving distance X of the above is obtained.

The operation of this embodiment with reference to FIG.
The description of the second embodiment will be referred to, and the description is omitted here.

In this embodiment constructed as described above, the primary coil 10 and the secondary coil 12 are made identical and the metal shaft 2
Can be assembled from the lateral direction. Embodiments 2 and 3
, The turns ratio of the primary coil 10 and the secondary coil 11 can be set without restriction.

(Embodiment 5) In the constructions of Embodiments 1 to 4, the metal shaft 2 is directly inserted into the inside of the sensor coil section 1. However, in this embodiment, as shown in FIG. A metal body 20 made of a magnetic material such as ferrite, which can incorporate detection characteristics from its material and shape into the design.
Is inserted into the resin jacket 22 and inserted into the sensor coil unit 1, and is connected to the external metal shaft 2 at the connection unit 21 made of resin (or metal). The linear motion of the metal shaft 2 is transmitted to the shaft 23 in the sensor coil unit 1 indirectly.

That is, the present embodiment uses a double coil in which the primary coil 11 and the secondary coil 12 are laminated and wound concentrically via the insulator 14 as shown in the figure, and a case portion accommodating the double coil. The bottomed cylindrical body 19 is inserted into a hole 18 corresponding to the center through hole of the primary coil 11 of the primary coil 13a, and the shaft 23 is arranged in the bottomed cylindrical body 19 so as to be able to move directly. , The shaft 23 adjusts the distance (gap) between the coils 11, 12 and the internal metal body 20 by the resin jacket 22.
To keep it constant. And the bottomed cylinder 19
The distal end of the metal shaft 2 is fitted and fixedly connected to the concave portion of the connecting portion 21 protruding outside from the one end opening so that the shaft 23 can be linearly moved along with the linear movement of the metal shaft 2. Has become. An inward projection 19a formed at one end opening of the bottomed cylindrical body 19 hits a step 22a formed on the resin outer cover 22 to constitute a slip-out preventing means for preventing the shaft 23 from falling out of the bottomed cylindrical body 19. I have.
In the figure, reference numeral 13b denotes an outer case of the fixed sensor block 1.

(Embodiment 6) In Embodiment 5, the metal member 2 made of a magnetic material such as ferrite of the substitute shaft 23 is used.
In the present embodiment, a metal body 20 made of a magnetic material such as ferrite is formed into a conical shape as shown in FIG. 13 in order to improve the linearity. Shapes that increase or decrease linearly or non-linearly so that they can be approximated (the diameter gradually increases or
) To make the nonlinearity due to magnetic effects such as magnetic path change and eddy current loss close to linear.

The amount of shaft movement D and the correction coefficient K (Dp) of the diameter D facing a certain point P of the sensor coil section 1 can be generally approximated by the following equation.

K (Dp) = kn (Dp / Dst) ⁿ ...
+ K2 (Dp / Dst) ² + k1 (Dp / Dst) + C Dst: reference movement amount, C: constant, k1, k2... Kn: proportional constant Note that the configuration is the same as that of the sixth embodiment except for the shape of the metal body 20. The same parts and symbols as in the configuration of FIG. 12 are denoted by the same reference numerals and symbols, and detailed description of the configuration of the sensor coil unit 1 and the shaft 23 is omitted.

(Embodiment 7) This embodiment relates to Embodiment 6
In addition to the structure for detecting the shaft linear motion described above, the same characteristics (basic characteristics,
A reference coil unit having a secondary coil for detection showing temperature characteristics) is provided in the sensor coil unit 1 and a signal from the reference coil unit is input to the sensor circuit 3 as a reference signal. The difference from the reference voltage output from the reference power supply circuit 36 is inverted and amplified by an error amplifier circuit 37 composed of an integrating circuit composed of an inverting amplifier, and the amplified output is fed back to the oscillation circuit 30 to increase the oscillation signal to a predetermined level or more. It is configured to hold.

Specifically, as shown in FIG. 14, a coil portion in which the primary coil 11 of the sensor coil portion 1 and the primary coil 41 of the reference coil portion 40 are connected in series is wound outside,
On the inner side, the secondary coil 12 of the sensor coil unit 1 and the secondary coil 42 for detection of the reference coil unit 40 have a coil structure.
Is located at a position where it cannot constantly face the shaft 23 even when the replacement shaft 23 moves. Conversely, the detection may be set so as to always face the shaft 23 for detection.

FIG. 15 shows a sensor circuit 3 used in this embodiment.
The sensor circuit 3 of the present embodiment comprises a primary coil 41 of a reference coil unit 40 and a sensor coil unit 1.
The capacitor C1 is connected in parallel to the series circuit with the primary coil 11 to form a parallel resonance circuit, and the oscillating circuit 30 generates a high-frequency magnetic field from both the primary coils 11 and 41.

Oscillation detected by the secondary winding 42 of the reference coil unit 40 is detected by the detection circuit 35, and the above-described feedback is performed by differential amplification (error amplification) by the error amplifier circuit 37.

The primary winding 41 of the reference coil unit 40 and the primary winding 11 of the sensor coil unit 1 are connected in parallel as shown in FIG. 16, so that the reference coil unit 40 is independent of the sensor coil unit 1. You may do it. In this case, the system can be maintained in a constant oscillation state by the above-mentioned feedback. . Further, the primary coils 11 and 41 may be arranged inside, and the secondary coils 12 and 42 may be arranged outside.

In the case of the present embodiment in which the reference coil section 40 is provided, even if the oscillation state of the oscillation circuit 30 fluctuates due to the influence of temperature or the like and the transmission ratio changes, the control can be performed in a stable direction.

Circuit elements having the same functions as those of the circuit of FIG. 7 in the circuits of FIGS. 15 and 16 are denoted by the same reference numerals and symbols, and description thereof is omitted. (Embodiment 8) In Embodiments 2 to 8, the primary coil 11 and the secondary coil 12 of the sensor coil unit 1 are both fixed, but the sensor coil unit 1 of this embodiment is shown in FIG. As shown in the figure, a resin jacket 22 in which a metal body 20 made of a magnetic material such as ferrite is inserted is formed in a coil bobbin shape.
(Or secondary coil 12) wound alternative shaft 2
3 ′, the fixed secondary coil 12 (or the primary coil 11) and the moving primary coil 11 (or the secondary coil 1)
A continuous signal is obtained from the transformer coupling (magnetic coupling) state that changes depending on the positional relationship between the two. The circuit shown in FIG. 7 is used as the sensor circuit 3. Also, the output of the moving side coil is taken out by a coil wire or the like which is led out so as not to be disconnected even by movement.

(Embodiment 9) In each of the above embodiments, the metal shaft 2 is inserted directly into the sensor coil unit 1 so as to be able to move linearly, or the replacement shafts 23 and 23 'provided in the sensor coil unit 1 are used. In this embodiment, the metal shaft 2 is coaxially connected. However, in the present embodiment, the replacement shaft 2 provided in the sensor coil unit 1 as shown in FIG.
An arm 2a fixed to the metal shaft 2 connects the shaft 20 with the metal shaft 2 arranged so as to be parallel to the 3 "linear motion direction so that the shaft 20 is linked to the linear motion of the metal shaft 2. It was done.

As the shaft 23 ″, a metal body made of a magnetic material such as ferrite or a metal body formed by inserting a metal body into a resin jacket as in the alternative shaft 23 shown in FIGS. 12 and 13 is used. The configuration is such that the distance (gap) between the metal body and the coil is kept constant.

(Embodiment 10) In each of the above embodiments, the sensor circuit 3 is provided in the sensor coil unit 1 or provided near the sensor coil unit 1. In this embodiment, as shown in FIG. The sensor circuit 3 is separated from the sensor coil unit 1 in position, so that the sensor circuit 3 is located near or incorporated in the arithmetic and control unit (ECU) 4 for a vehicle. Other configurations are the same as in the first embodiment,
Needless to say, the present invention can be applied to any embodiment other than the first embodiment.

The linear motion of the shaft in the present invention includes not only the case where the shaft moves linearly but also the case where the shaft advances and retreats in the axial direction while rotating. Of course it is good.

[0075]

According to the first aspect of the present invention, the sensor coil section comprising one or more coils and the high-frequency magnetic field generated from the coil of the sensor coil section are arranged so as to be able to move directly and interlock with the movement of the object to be detected. A metal shaft, and a sensor circuit that extracts a magnetic field change amount that changes according to the positional relationship between the sensor coil portion and the shaft by a continuous signal, so that a singular point and an extreme value corresponding to a moving distance due to direct movement of the shaft are provided. It is possible to take out continuous signals without noise, so that stable detection can be performed even if the shaft is misaligned, linearity is stable even if the amount of shaft movement increases, and changes over time because no permanent magnet is used. There is an effect that stable performance can be maintained without any problem.

According to a second aspect of the present invention, in the first aspect of the present invention, the sensor circuit includes an oscillation circuit for generating a high-frequency magnetic field in the coil of the sensor coil unit, and a coil and a shaft of the sensor coil unit for generating the high-frequency magnetic field. A detection circuit that detects a change in the oscillation state of the oscillation circuit due to a positional relationship, a detection amplification circuit that detects and amplifies a detection signal of the detection circuit, and a filter that cuts an unnecessary frequency band from an output signal from the detection amplification circuit It consists of a circuit and an output buffer circuit that outputs the output signal of the filter circuit with low impedance and outputs a proportional relationship between the output signal voltage and the moving distance of the shaft, so that it is not affected by ripples etc. This has the effect that a stable detection signal can be obtained.

According to the third aspect of the present invention, an exciting coil for generating a high-frequency magnetic field, a sensor coil part in which the exciting coil is double-wound and both coils are transformer-coupled, and an inner coil of the sensor coil part A metal shaft that is linearly movable in the central through-hole, and a sensor that extracts the amount of change in the transformer coupling state that changes according to the positional relationship between the sensor coil and the shaft with a continuous signal, in conjunction with the movement of the object to be detected. Circuit, a stable high-frequency magnetic field can be generated from the excitation coil, and relative signal processing can be performed only by relying on variations in the turns ratio, reducing the effects of absolute variations. There is an effect that can be.

According to a fourth aspect of the present invention, there is provided a sensor coil section having an exciting coil for generating a high-frequency magnetic field, and a detecting coil which is disposed in such a manner that the exciting coil is coaxially and linearly connected and is transformer-coupled. , A metal shaft that is arranged to be able to move directly in the center through holes of both coils of the sensor coil part, and that changes in the transformer coupling state that changes according to the positional relationship between the sensor coil part and the shaft in conjunction with the movement of the detected object With a sensor circuit that extracts the amount as a continuous signal, a stable high-frequency magnetic field can be generated from the excitation coil, and relative signal processing can be performed only by relying on variations in the turns ratio. The effect of the absolute variation can be reduced and there is no restriction on the winding ratio of both coils.

According to a fifth aspect of the present invention, there is provided a sensor coil unit having an exciting coil for generating a high-frequency magnetic field and having a coil and a detecting coil which is transformer-coupled to the coil, the axial direction being the same direction and arranged with a predetermined gap therebetween. A metal shaft that is disposed in a gap between the two coils of the sensor coil unit so as to be able to move linearly in a direction perpendicular to the axial direction of the two coils, and that interlocks with the movement of the object to be detected; And a sensor circuit that extracts the amount of change in the transformer coupling state that changes with the positional relationship as a continuous signal, so that a stable high-frequency magnetic field can be generated from the excitation coil, and that it depends on variations in the turns ratio. Can perform relative signal processing, reduce the effects of absolute variations, and make the two coils of the sensor coil unit the same. There is an effect that can be assembled from the side.

According to the sixth aspect of the present invention, a sensor coil unit including an exciting coil for generating a high-frequency magnetic field and a detecting coil, and one of the detecting coil and the exciting coil is connected to a sensor coil unit. A shaft wound around the shaft and arranged in a central through-hole of the other coil so as to be able to linearly move together with the one coil, and a change in a transformer coupling state that changes due to a positional relationship between the two coils of the sensor coil portion due to movement of the shaft With the provision of the sensor circuit for extracting the quantity as a continuous signal, there is an effect that the stability of the change in the transmission ratio can be improved in accordance with the direct movement of the shaft in the sensor coil portion having a complete transformer structure.

According to a seventh aspect of the present invention, in any one of the third to sixth aspects of the present invention, the sensor circuit includes: an oscillation circuit for generating a high-frequency magnetic field in an excitation coil of the sensor coil unit; A detection circuit that detects a change in state from the output of the detection coil, a detection amplification circuit that detects and amplifies the detection signal of the detection circuit, and a filter circuit that cuts unnecessary frequency ranges from the output signal from the detection amplification circuit. And an output buffer circuit that outputs the output signal of the filter circuit with low impedance and outputs the output signal voltage and the moving distance of the shaft because the output signal voltage and the moving distance of the shaft have a proportional relationship. Has a proportional relationship between them, so that there is an effect that a stable detection signal can be obtained without being affected by ripples or the like.

According to the eighth aspect of the present invention, in any one of the first to seventh aspects of the present invention, the shaft is a metal shaft which directly moves the object to be detected, so that the structure is simple.

According to a ninth aspect of the present invention, in any one of the first to seventh aspects of the present invention, the shaft is linearly connected to a metal shaft, which is provided outside the sensor coil portion and directly moves the object to be detected. At least by another metal body that interlocks with the linear motion of the metal shaft, and the distance between the circumferential surface of the metal body and the inner circumferential surface of the coil of the sensor coil portion facing the same is kept constant. Compared with the case where the metal shaft is directly used, a shaft made of a metal body whose characteristics are known in advance can be used, so that there is an effect that stable detection is possible.

According to a tenth aspect of the present invention, in the ninth aspect of the present invention, since the metal body is linearly corrected by shape processing, an approximate linear signal can be obtained with respect to direct movement of the shaft. There is an effect that the linearity can be stabilized even if the moving amount increases.

According to an eleventh aspect of the present invention, in any one of the first to seventh aspects of the present invention, the shaft is an arm fixed to a metal shaft, which is provided outside the sensor coil portion and moves directly on the object to be detected. At least a separate metal body connected in parallel with the linear motion of the metal shaft and connected with the metal shaft, while maintaining a constant distance between the circumferential surface of the metal body and the inner circumferential surface of the coil of the sensor coil unit facing the same. Therefore, when an unspecified metal shaft is used directly, it is possible to use a shaft made of a metal body whose characteristics are known in advance, so that stable detection is possible, and furthermore, the sensor coil portion is separated from the metal shaft axis. It can be installed, and there is an effect that the degree of freedom in mounting the sensor coil portion is improved.

According to a twelfth aspect of the present invention, in any one of the first to tenth aspects, a reference coil unit having the same characteristics as the sensor coil unit is provided in parallel, and an output from the reference coil unit is provided in the sensor circuit. A means is provided to control the operation of generating a magnetic field in the coil of the sensor coil so that the output voltage signal of the reference coil is constant by amplifying the difference between the signal voltage and the reference voltage. There is an effect that stable detection can be performed with respect to operation variation, there is no need to take measures for temperature compensation on the external arithmetic and control unit side, and the resolution can be improved.

According to a thirteenth aspect of the present invention, in any one of the first to eleventh aspects, the sensor circuit is provided at a position separated from the sensor coil portion by a coil wire derived from the sensor coil portion. The coil part and the sensor circuit can be installed separately, which enables the sensor circuit to be installed in an environmentally advantageous place such as a temperature away from a narrow place where the sensor coil part is provided. effective.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a sensor circuit used in the embodiment.

FIG. 3 is an explanatory diagram of an output signal voltage of the sensor circuit according to the first embodiment.

FIG. 4 is a circuit configuration diagram of another sensor circuit used in the embodiment.

FIG. 5 is a configuration diagram of Embodiment 2 of the present invention.

FIG. 6A is a side sectional view of the sensor coil unit according to the first embodiment. (B) is an AA 'sectional view of (a).

FIG. 7 is a circuit configuration diagram of a sensor circuit used in the Embodiment.

FIG. 8 is an explanatory diagram of an output signal voltage of the sensor circuit according to the first embodiment.

FIG. 9 is a configuration diagram of a third embodiment of the present invention.

FIG. 10 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 11A is a side sectional view of the sensor coil unit according to the third embodiment. (B) is an AA 'sectional view of (a).

FIG. 12 is a configuration explanatory view of a sensor coil unit according to a fifth embodiment of the present invention.

FIG. 13 is a diagram illustrating a configuration of a sensor coil unit according to a sixth embodiment of the present invention.

FIG. 14 is an explanatory diagram illustrating a configuration of a sensor coil unit according to a seventh embodiment of the present invention.

FIG. 15 is a circuit configuration diagram of a sensor circuit used in Embodiment 1;

FIG. 16 is a circuit configuration diagram of a sensor circuit corresponding to a sensor coil unit of another embodiment of the above.

FIG. 17 is a diagram illustrating a configuration of a sensor coil unit according to an eighth embodiment of the present invention.

FIG. 18 is an explanatory diagram of a configuration of a ninth embodiment of the present invention.

FIG. 19 is a diagram illustrating a configuration of a sensor coil unit according to a tenth embodiment of the present invention.

FIG. 20 is a configuration diagram of a conventional example.

FIG. 21 is a configuration diagram of another conventional example.

FIG. 22 is a diagram illustrating a problem of a signal voltage of a conventional non-contact position sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor coil part 2 Shaft 3 Sensor circuit 4 Arithmetic control device for automobile 5 Backlight 6 Ignition 10 Coil

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F063 AA02 BA11 CA08 CB01 CB05 DA01 DA04 DB03 DC08 DD02 GA04 GA15 GA16 GA27 GA29 GA52 GA80 LA05 LA06 LA11 LA23 2F077 AA21 FF02 FF03 FF12 FF16 TT06 TT07 TT35 3J052 AA75 GC17

Claims (13)

[Claims] 1. A sensor coil section comprising one or more coils, a metal shaft disposed so as to be able to move directly in a high-frequency magnetic field generated from a coil of the sensor coil section, and interlocked with the movement of an object to be detected. A non-contact type position sensor, comprising: a sensor circuit for extracting, as a continuous signal, a magnetic field change amount that changes according to a positional relationship between the sensor coil unit and the shaft. 2. A sensor circuit comprising: an oscillation circuit for generating a high-frequency magnetic field in a coil of a sensor coil unit; and a change in an oscillation state of the oscillation circuit caused by a positional relationship between a coil of the sensor coil unit for generating a high-frequency magnetic field and a shaft. Detection circuit, a detection amplification circuit that detects and amplifies the detection signal of the detection circuit, a filter circuit that cuts unnecessary frequency bands from an output signal from the detection amplification circuit, and a low impedance output signal of the filter circuit. 2. A non-contact position sensor according to claim 1, further comprising an output buffer circuit for outputting the output signal and a proportional relationship between the output signal voltage and the moving distance of the shaft. 3. An exciting coil for generating a high-frequency magnetic field, a sensor coil portion in which the exciting coil is double-wound and both coils are transformer-coupled, and a central through hole of an inner coil of the sensor coil portion. It is provided with a metal shaft that is arranged so as to be able to move linearly and interlocks with the movement of the object to be detected, and a sensor circuit that extracts the amount of change in the transformer coupling state that changes according to the positional relationship between the sensor coil and the shaft with a continuous signal. Non-contact type position sensor characterized by the above-mentioned. 4. A sensor coil section having an excitation coil for generating a high-frequency magnetic field, a coil for detection, which is arranged so that the excitation coil is coaxially and linearly connected and transformer-coupled, A continuous signal is provided in the center through-holes of both coils so that the amount of change in the transformer coupling state that changes according to the positional relationship between the sensor coil section and the shaft, and the amount of change in the transformer coupling state that is linked to the movement of the object to be detected, are linearly movable. A non-contact position sensor, comprising: a sensor circuit for extracting. 5. A sensor coil unit comprising: an excitation coil for generating a high-frequency magnetic field, which is arranged with a predetermined gap in the same axial direction, and a detection coil transformer-coupled to the coil; A metal shaft that is disposed in the gap between the coils so as to be able to move linearly in a direction orthogonal to the axial direction of both coils, and that interlocks with the movement of the detected object;
A non-contact position sensor, comprising: a sensor circuit for extracting, as a continuous signal, a change amount of a transformer coupling state that changes according to a positional relationship between both coils of the sensor coil unit and the shaft. 6. A sensor coil section comprising an excitation coil and a detection coil for generating a high-frequency magnetic field, and one of a detection coil and an excitation coil wound around the sensor coil. A continuous signal is used to indicate the amount of change in the transformer coupling state that changes in the positional relationship between the two coils of the sensor coil unit due to the movement of the shaft and the shaft that is linearly movable together with the one coil in the center through hole of the other coil. A non-contact position sensor, comprising: a sensor circuit for extracting. 7. A sensor circuit comprising: an oscillation circuit for generating a high-frequency magnetic field in an excitation coil of a sensor coil unit; a detection circuit for detecting a change in a transformer coupling state of the sensor coil unit from an output of the detection coil; A detection amplification circuit that detects and amplifies a detection signal of the detection circuit, and a filter circuit that cuts out unnecessary frequency ranges from an output signal from the detection amplification circuit,
7. An output buffer circuit which outputs an output signal of the filter circuit with a low impedance and outputs the output signal, wherein the output signal voltage and the moving distance of the shaft have a proportional relationship. The non-contact type position sensor described in the above. 8. A non-contact position sensor according to claim 1, wherein said shaft is a metal shaft which directly moves an object to be detected. 9. The shaft is at least constituted by another metal body which is linearly connected to a metal shaft of the object to be detected which is provided outside the sensor coil section and which is linearly connected to the linear movement of the metal shaft. The non-contact position sensor according to any one of claims 1 to 7, wherein a distance between a peripheral surface of the metal body and an inner peripheral surface of the coil of the sensor coil unit facing the peripheral surface is kept constant. 10. The non-contact position sensor according to claim 9, wherein said metal body is linearly corrected by shape processing. 11. The above-mentioned shaft is connected to a metal shaft provided on the outside of the sensor coil unit, which is fixed to a metal shaft which moves directly on the object to be detected, via an arm fixed thereto. 8. The sensor according to claim 1, wherein a distance between a peripheral surface of the metal body and an inner peripheral surface of the coil of the sensor coil part facing the metallic body is kept constant. Contact type position sensor. 12. A reference coil unit having the same characteristics as the sensor coil unit is provided in parallel, and a differential amplification between an output signal voltage from the reference coil unit and the reference voltage is performed in the sensor circuit to output the reference voltage from the reference coil unit. The non-contact position sensor according to any one of claims 1 to 11, further comprising means for controlling an operation of generating a magnetic field by a coil of the sensor coil unit so that a signal is constant. 13. The contactless position according to claim 1, wherein a sensor circuit is provided at a position separated from the sensor coil portion by a coil wire derived from the sensor coil portion. Sensors.