JPH0786422B2 - Method of manufacturing rod portion in linear position detecting device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction type linear position detecting device which changes an induction coefficient according to a relative displacement of a core with respect to a coil and obtains an output signal corresponding to the induction coefficient. The present invention relates to a method of manufacturing a rod portion in a linear position detecting device that can obtain a change in the induction coefficient with the parameter as a parameter.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 57-1210 discloses a differential transformer using a weak magnetic metal such as copper or aluminum as a core in place of the conventionally known differential transformer having an iron core as a core. . This utilizes the change in the magnetic resistance due to the eddy current loss generated in the metal having good conductivity and weak magnetic field in the magnetic field, instead of causing the change in the magnetic resistance according to the displacement of the ferromagnetic core such as iron. On the other hand, as a variable magnetic resistance type linear position detecting device, a phase shift type device in which the linear position is evaluated by the electrical phase angle of an output AC signal is disclosed in Japanese Utility Model Application Laid-Open No. 58-136718.
This is one in which magnetic cores of a prescribed length are arranged at prescribed intervals.

[0003]

However, the conventional eddy current type differential transformer like the former can be used only for linear position detection in a relatively small range, like the well-known iron core type differential transformer. In addition to that, the linear position detected depending on the magnitude of the output analog voltage level is evaluated, so that there is a drawback that malfunction is likely to occur due to the influence of disturbance and noise. On the other hand, in the latter variable reluctance type linear position detecting device, since magnetic cores of a predetermined length are arranged at a predetermined interval, it is possible to detect a linear position over a long range. However, processing many magnetic cores,
There was a limit to reducing the manufacturing cost because it had to be assembled.

The present invention has been made in view of the above points, and a linear position detecting device capable of obtaining a change in induction coefficient with eddy current loss as a parameter is capable of detecting a linear position over a relatively long range. At the same time, it is an object of the present invention to provide a manufacturing method that enables accurate linear position detection by the phase shift method and that can provide such a linear position detecting device at a relatively low cost.

[0005]

A manufacturing method according to the present invention has at least two primary coils that are respectively excited by primary AC signals that are out of phase with each other, and a secondary coil corresponding to the primary coils. A coil portion and a rod portion arranged so as to be linearly displaceable relative to the coil portion are provided so that the rod portion can form an eddy current path for the magnetic flux generated by the coil portion. A plurality of electrically conductive parts are repeatedly provided at a predetermined interval along the relative linear displacement direction, and the electrically conductive parts are made of a weakly magnetic or non-magnetic material and the material of the other part of the rod portion. Is composed of a relatively good conductor, and
By arranging the primary coil and the secondary coil such that the correspondence between the primary coil and the conductor portion of the rod portion is deviated between the primary coils, the primary AC signal is transmitted to the rod portion relative to each other. A signal phase-shifted according to the linear position is obtained on the side of the secondary coil, and this phase shift amount is 360 per linear displacement amount corresponding to one repeating cycle of the arrangement of the conductor portions in the rod portion. A method of manufacturing the rod portion in a linear position detecting device, characterized in that the arrangement of the coil portion is determined so as to correspond to an electrical angle of a predetermined degree, wherein a predetermined conductivity is provided on the entire surface of the base material of the rod portion. depositing a material, and, thereafter, the Remove-out unnecessary portions leaving the conductive material deposited on said substrate in a predetermined pattern, the remaining conductive material is the conductive
Becoming a part and then said conductive
Is relatively less conductive or non-conductive than a substance and
The surface of the rod part is made of non-magnetic or weakly magnetic material.
It is characterized by comprising coating .

[0006]

In the linear position detecting device manufactured according to the method of the present invention, the conductor portions provided so as to form the eddy current path with respect to the magnetic flux generated by the coil portion are spaced at predetermined intervals along the relative linear displacement direction. A plurality of them are repeatedly provided, and the coil portion of the coil portion is formed so that an electrical phase shift corresponding to an electrical angle of 360 degrees occurs for a linear displacement amount corresponding to one repeating cycle of the arrangement of the conductor portions. By deciding the arrangement, it becomes possible to detect over a long range in a linear position detection device that uses the magnetoresistance change according to the eddy current loss of the conductor, and at the same time, the function of the magnetoresistance change with respect to the linear displacement has periodicity It is possible to achieve this, and there is an excellent effect that it is possible to detect a linear position with high accuracy by the phase shift method. By the way, in the case of using the single conductor core shown in the above-mentioned prior art, it was impossible to impart a periodicity to the change in the magnetic resistance, and it was essentially difficult to convert it to the phase shift method. .

Since the eddy current has a property of flowing near the surface of the conductor, the conductor portion to be provided on the rod portion is not required to be so thick. Therefore, the conductor portion can be attached on the base material of the rod portion in a predetermined pattern. This means that the manufacture of the rod part is made very easy. That is, the pattern of such a relatively thin conductor portion can be formed relatively easily on the base material of the rod portion by an appropriate surface processing treatment such as plating, spraying, pattern baking or etching. Therefore, it is possible to omit the troublesome machining and assembly which are found in the iron core type shown in the above-mentioned prior art, simplify the manufacturing process, and reduce the manufacturing cost. , Which has an excellent effect.

According to the manufacturing method of the present invention,
First, a relatively thin layer of the conductive material is formed on the entire surface of the rod portion by depositing a predetermined conductive material on the entire surface of the base material of the rod portion. Then, after that, the conductive material adhered on the base material of the rod portion is left in a predetermined pattern to remove unnecessary portions, so that a desired repeating pattern of the conductor portion is formed by the remaining conductive material. Can be done. Therefore, the rod portion can be easily and efficiently processed and manufactured, the manufacturing cost can be reduced, the pattern of the minute conductive material can be easily formed, and the rod can be refined. Is. In addition, it is relatively
Low conductivity or non-conductivity and non-magnetic or weak magnetic
I tried to cover the surface of the rod part with a substance
So, the surface of the rod part can be protected smoothly,
Has the effect.

The rod portion manufacturing method according to the present invention can be advantageously applied to the following linear position detecting device. At least two primary coils each excited by primary AC signals that are out of phase with each other, and
There are a plurality of linear position detecting devices each including a coil part having a secondary coil corresponding to the next coil and a rod part arranged so as to be linearly displaceable relative to the coil part. The rod portion is formed by repeatedly providing a plurality of conductor portions provided so as to form an eddy current path for the magnetic flux generated by the coil portion along the relative linear displacement direction at predetermined intervals. The conductor portion is made of a weak magnetic material or a non-magnetic material and is made of a conductor that is relatively good as compared with the material of the other portions of the rod portion, and the rod portion of each of the detection devices has a common base. The rods are made of a material, and the conductor portions corresponding to the rod portions are independently provided on the common base material, and the repeating intervals of the conductor portions are different between the rod portions. And In each of the detecting devices, the primary AC signal is arranged by arranging the primary coil and the secondary coil such that the correspondence between the primary coil and the conductor portion of the rod portion is deviated between the primary coils. Is obtained on the secondary coil side in accordance with the relative linear position of the rod portion, and the phase shift amount is
A linear position detecting device, wherein the arrangement of the coil portions is determined so as to correspond to an electrical angle of 360 degrees for a displacement amount corresponding to one repeating cycle of the arrangement of the conductor portions in the rod portion. . As described above, by making the base material of the rod portion common to the plurality of linear position detecting devices, the manufacturing can be further facilitated and the manufacturing cost can be further reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. 1 and 2, the coil portion includes primary coils 1A to 1D and secondary coils 2A to 2D, and a rod portion 6 is inserted into these coil spaces so as to be relatively linearly movable. The rod portion 6 includes a relatively long center rod 6a and a conductor portion 6b provided in a ring shape around the center rod 6a. The width of the conductor portion 6b is P / 2 (where P is an arbitrary number), and the relative linear displacement direction of the rod portion 6 (direction of arrows L and / L in the drawing; "/ L" means "bar L "Indicates"), a plurality of conductor portions 6b are repeatedly provided at a predetermined interval P / 2. The conductor portion 6b is made of a weakly magnetic or non-magnetic material and is made of a good conductor relatively to the material of the center rod 6a. For example, copper or aluminum or brass or a good conductive material such as brass is used. A mixture or mixture of other substances can be used. The center rod 6a may use either a magnetic material or a non-magnetic material, and may be metal or non-metal (synthetic resin, glass, ceramic, etc.). The point is that the electrical resistivity is higher than that of the conductor portion 6b (the one with poor conductivity).
Is used as the center rod 6a. This is to allow more eddy current to flow only in the portion of the conductor portion 6b that is intermittently provided, and to obtain a periodic magnetoresistance change with respect to displacement.

In this embodiment, the coils are arranged to operate in four phases. For the sake of convenience, these phases are distinguished by using the symbols A, B, C, and D. According to the relative position of the ring-shaped conductor portion 6b with respect to the coil, the magnetic resistance generated in each of the phases A to D is shifted by 90 degrees. For example, when the A phase is the cosine phase, the B phase is the sine phase, Arrangement of the coils and the conductor portion 6b so that the C phase is the minus cosine phase and the D phase is the minus sine phase.
Has been determined.

In the example of FIG. 1, the primary coils 1A to 1D and the secondary coils 2A to 2D of the respective phases A to D are wound at the same positions, and the coil lengths of the individual coils are the same. It is almost “P / 2”. And the A-phase coils 1A and 2
A and C phase coils 1C and 2C are provided adjacent to each other, and B phase coils 1B and 2B and D phase coils 1D and 2D are provided.
Are also adjacent to each other. The distance between the A and C phase coil groups and the B and D phase coil groups is "P {n ±
(1/4)} ”(n is an arbitrary natural number). Accordingly, the phase of the reluctance change of the magnetic circuit in the B and D phases can be shifted by 90 degrees (1/4 of one pitch P) with respect to the reluctance change of the magnetic circuit in the A and C phases.

A-phase and C-phase coils 1A, 2A, 1C,
2C is housed in a cylindrical case 4 made of a magnetic material such as iron, and has B-phase and D-phase coils 1B, 2B, 1D, 2
D is also stored in the same cylindrical case. These iron cases 4 and 5 are for preventing crosstalk between the coils and for concentrating the magnetic force lines of the coils to enhance the coupling of the magnetic circuit. In the above structure, the magnetic fluxes from the primary coils 1A to 1D of the respective phases pass through the magnetic body cases 4 and 5 and the rod portion 6, and when the conductor portion 6b enters the magnetic field, it depends on the penetration amount. The conductor portion 6b
Eddy current flows along the ring. This conductor portion 6b
The more eddy current flows in the coil (for example, the state corresponding to the phase A in FIG. 1 at the maximum), the more eddy current flows. On the contrary, almost no eddy current flows in the state where the conductor portion 6b has not entered the coil at all (for example, the state of phase C in FIG. 1). In this way, an eddy current flows through the conductor portion 6b according to the degree of penetration of the conductor portion 6b into the coil of each phase, and a magnetic resistance change due to this eddy current loss is generated in the magnetic circuit of each phase. Secondary coil 2A for each phase
An AC signal of a level corresponding to this magnetic resistance is induced in 2D.

In the example of FIG. 1, a space is formed between the conductor portions 6b, but as shown in FIG. 3, an appropriate filler 3 may be filled therein. The filler 3 has a lower conductivity or non-conductivity than the conductor portion 6b, and uses a non-magnetic or weakly magnetic substance. This filling 3 is made up of conductor parts 6
Not only the space between b but also the entire outer periphery of the rod portion 6 may be covered as shown in the figure.

4 to 6 show examples of different structures of the rod portion which can be replaced with the rod portion 6 of FIG. In the rod portion 7 of FIG. 4, a ring-shaped conductor portion 7b having a width P / 2 and spacers 7a are alternately fitted inside the tube 7c. Since the central portion of the rod portion 7 is hollow, there is an advantage that the weight can be reduced. The rod portion 8 of FIG.
A disk-shaped conductor portion 8 having a width P / 2 inside the tube 8c
b and the spacer 8a are alternately fitted. The conductor portions 7b and 8b have the same electrical and magnetic properties as those of the above-mentioned 6b, and the tubes 7c and 8c and the spacer 7a,
8a has a relatively low conductivity or non-conductivity relative to the conductor portion and is non-magnetic or weakly magnetic. The rod portion 9 of FIG.
A ring-shaped groove is provided around the center rod 9a, and a conductor portion 9b is provided in this groove. Therefore, the ring-shaped protrusion 9c around the center rod 9a is located between the conductor portions 9b. The center rod 9a has a lower conductivity or non-conductivity than the conductor portion 9b, and is a non-magnetic or weak magnetic substance.

In the embodiment shown in FIG. 1, the coils of the respective phases are housed in the cylindrical magnetic body cases 4 and 5, and these cases 4 and 5 can form a magnetic path. It is also possible to carry out the present invention without providing a body case. FIG. 7 shows an example of such a case, and is the same as FIG. 1 except that the coils 1A to 1D and 2A to 2D of the phases A to D are housed in a non-magnetic case (not shown) instead of the magnetic body case. It is the structure of. It is possible to replace the rod portion 6 of FIG. 7 and use the rod portions 6 to 9 of FIGS. 3 to 6.

The arrangement and number of coil portions are not limited to those shown in FIGS. 1 and 7, and the design can be changed as needed. For example, in FIG. 8, the distance P is divided into approximately three equal parts and the A-phase secondary coil 2 is
A primary coil 1AC common to the A, A, and C phases and a secondary coil 2C of the C phase are arranged and housed in a magnetic material case 4 '. Similarly, for the B and D phases, the magnetic material case 5 is also used. '
The secondary coil 2B, the common primary coil 1BD, and the secondary coil 2D are housed in. Similar to the above, instead of the rod portion 6, the rod portions 6 to 9 in FIGS. 3 to 6 may be used. Further, the magnetic body cases 4'and 5'may not be used. In each of the above-described embodiments, the rod portion is inserted into the space inside the coil. However, the structure is not limited to this, and the design can be changed as necessary.

FIG. 9 shows a modification of the coil portion, and FIG. 10 is a sectional view taken along line XX thereof. U-shaped magnetic cores 11, 12, 1 provided with primary and secondary coils 1A-1D, 2A-2D corresponding to each phase A-D for each phase, respectively.
It is wound around both legs of 3,14 respectively. The coil part cores 11 to 14 of the respective phases A to D are fixed to each other in a predetermined arrangement so that the cycles of magnetic resistance change are deviated by ¼ cycle (90 degrees) between the adjacent phases. For example, the interval between the cores 11 to 14 between adjacent phases is 3P / 4 (P in a broad sense).
It should be {1 ± (1/4)}). The rod portion 6 has the same structure as that shown in FIG. The distance between both ends of each of the U-shaped cores 11 to 14 substantially corresponds to the width P / 2 of the conductor portion 6b. In each phase, the U-shaped cores 11 to 14 pass through the rod portion 6 from one end of the U-shaped cores 11 to 14, and the like. A magnetic circuit is formed at each end. Also in this embodiment, instead of the rod portion 6, the rod portion 6 shown in FIGS.
~ 9 can be used. Further, in FIG. 9, the cores 11 to 14 of each phase are aligned in the linear displacement direction,
The present invention is not limited to this, and as shown by broken lines 12 ', 13', and 14 'in FIG. In that case, the interval between the adjacent phases in the linear displacement direction is not limited to 3P / 4 and can be made shorter (for example, P / 4).
In the example of FIG. 9, the eddy current path generated in the conductor portion 6b is formed around the magnetic flux path perpendicular to the ends of the cores 11 to 14 rather than being formed along the ring shape.
Therefore, in this case, the conductor portions 6b to 9b of the rod portions 6, 7, 8, and 9 do not necessarily have to be ring-shaped, and a certain degree of (vortex It suffices if the area is large enough to form a current path.

The rod portion is not limited to the round bar shape shown in the above embodiment, but may be an elongated flat plate type as described below. The detection device having the flat rod portion is advantageous when the round rod portion is attached to a portion that is not suitable for attachment.

In the embodiment shown in FIG. 11, the coil portion has U-shaped cores 11 to 14 for each of the phases A to D arranged in a line at a predetermined interval 3P / 4 in the linear displacement direction, as in FIG.
It includes primary and secondary coils 1A to 1D and 2A to 2D wound around the cores 11 to 14, respectively. This core 11-14
The plate-shaped rod portion 15 is disposed so as to face the end portion of each of the rod portions 6 and 9 with a predetermined gap interposed therebetween.
Similarly, the linear displacement is possible relative to the coil part. In the flat rod portion 15, conductor portions 15b are repeatedly provided at a predetermined interval P / 2 on the side facing the ends of the cores 11 to 14. FIG. 12 is a plan view of the flat rod portion 15. The conductor portion 15b is made of the same material as the conductor portion 6b of FIG. 1, and the substrate member 15a is made of the same material as the center rod 6a of FIG. 13 is a sectional view taken along the line XIII-XIII in FIG.

In FIG. 11, the coil portion cores 11 of the respective phases A to D are shown.
14 are arranged in a straight line in the linear displacement direction.
1 may be arranged in a lateral row while maintaining a P / 4 distance from each other in the linear displacement direction.
As in the fifth embodiment, the cores 11 to 14 of the phases A to D are aligned in a horizontal direction (a direction perpendicular to the linear displacement direction), and the arrangement pattern of the conductor portions 17b corresponding to the phases A to D is arranged. P
It may be shifted by / 4. 14 and 15 are plan views, and the coil portion cores 11 to 1 of the respective phases A to D are shown.
In FIG. 4, primary and secondary coils are wound around both feet of each, as in FIG. The flat rod portion 16 is shown in FIG.
Although a plurality of conductor portions 16b are repeatedly provided on the substrate member 16a at a predetermined interval P / 2 in the same manner as in the flat rod portion 15, the width is wider than the rod portion 15. In the flat rod portion 17, the conductor portion 17b corresponding to each of the phases A to D has an arrangement interval of P / 2, but between adjacent phases, the arrangement pattern is displaced by P / 4 in the linear displacement direction. . Reference numeral 17a is a substrate member.

In the embodiment of FIGS. 11 to 15, the cores 11 to 14 of the coil portion are U-shaped, and both ends thereof face only one side of the flat rod portion, but as shown in FIG. Alternatively, the cores 18 to 21 of each phase coil portion may be C-shaped, and the flat rod portion 22 may be inserted between both ends of each core. 17 is a plan view of the flat rod portion 22, and FIG. 18 is a sectional view taken along line VIII-VIII of FIG. The primary and secondary coils 1A to 1D are wound around the cores 18 to 21 of the respective phases A to D as described above. Flat rod part 2
A plurality of conductor portions 22b are provided on both surfaces of No. 2 at a predetermined interval P / 2 along the linear displacement direction. The conductor portions 22b may be arranged on only one side. 22a is a substrate member.

In the embodiment of FIG. 19, the cores 18 to 21 of each phase coil portion are C-shaped as in FIG. 16, and the flat rod portion 45 is inserted between both ends of each core.
20 is a plan view of the flat rod portion 45, and FIG. 21 is FIG.
11 is a sectional view taken along line IIXI-IIXI of FIG. On both surfaces of the flat rod portion 45, conductor portions 45b having a ring-shaped pattern are provided. The width of the ring-shaped conductor portion 45b is 3P / 4, and this is repeatedly provided at intervals of P / 4. Similar to the above, the pattern arrangement of the conductor portion 45b may be only one side. 45a is a substrate member.

In the embodiment of FIG. 22, the rod portion 46 is formed by providing a conductor portion 46b in a spiral shape around the center rod 46a. The spiral conductor portion 46b is
They are arranged in a pattern of single thread having a pitch width of P. In FIG. 22, the rod portion 46 is shown in a side view.
FIG. 23 is a sectional view taken along the line IIXIII-IIXIII of FIG. 22, and as shown at the same time, U-shaped cores 47 to 50 of each phase A to D are provided around the rod portion 46 at intervals of 90 degrees,
A primary coil 1A to 1D and a secondary coil 2A to 2D are wound around each core 47 to 50.

In the embodiment shown in FIG. 24, the rod portion 51 is formed by providing a spiral-shaped conductor portion 46b around a center rod 51a in a double thread pattern having a pitch of 2P. FIG. 25 is a cross-sectional view taken along the line VV of FIG. 24, in which eight cores 52 to 5 are arranged around the rod portion 51 at intervals of 45 degrees.
9 is provided. Two cores facing each other at an interval of 180 degrees are in phase with each other, and there are four pairs of cores composed of two cores, and each pair corresponds to phase A to phase D, respectively. The primary coils 1A to 1D and the secondary coils 2A to 2D are wound around the cores 52 to 59 of the phases A to D, respectively, as described above. In-phase secondary coil outputs are added together.

22 to 25, the central rod 46
Reference numerals a and 51a are made of the same material as the central rod 6a of FIG. The coil part cores 47 to 50 or 52 to 59 of the respective phases A to D are fixed to each other in the arrangement shown, and the rod parts 46 and 51 are linearly displaced relative to the coil parts (arrow L or / Can be displaced in the L direction). Therefore, it operates in the same manner as the embodiments described above. In the 8-pole type coil portion (the coil having the same phase at a 180-degree symmetrical position) as shown in FIG. 25, the center of the rod portion 51 is slightly deviated from the center of the space in each of the cores 52 to 59 and a gap is formed. Even if the width varies, the error is canceled by the addition of the in-phase outputs at the 180-degree symmetrical positions, which is advantageous. The conductor portions 46b and 51b are the core 47 of each phase.
It may be provided only at the positions corresponding to 50 to 52 to 59.

In the embodiments of FIGS. 1 to 25, an output signal according to the relative linear position of the rod portion can be obtained by the phase shift method. That is, in each of the phases A to D, a periodical magnetic resistance change occurs with the linear displacement amount P of the rod portion as one cycle, and the phase of this magnetic resistance change is deviated by 90 degrees (P / 4) between adjacent phases. . Therefore, if the phase angle corresponding to the linear position is represented by φ, the level of the voltage induced in the secondary coils 2A to 2D of the respective phases A to D is approximately according to the relative linear position of the rod portion (that is, φ). Cosφ for A phase, sinφ for B phase, −co for C phase
In the sφ and D phases, it can be represented by a simplified formula of −sinφ (2π corresponds to P). A-phase and C-phase primary coil 1
A and 1C are excited by the sine wave signal sinωt, and the B-phase and D-phase primary coils 1B and 1D are excited by the cosine wave signal cosωt. Then, for A and C relative, the outputs of the resulting secondary coils 2A and 2C are differentially added, and B and D are added.
The relative outputs of the secondary coils 2B and 2D resulting from the relative addition are differentially added, and the differential output signals of each pair are added and combined to obtain the final output signal Y. Then, the output signal Y can be substantially expressed by the following simplified formula. Y = sin ωtcosφ-(-sinωtcosφ) + cosωtsinφ-(-cosωtsinφ) = 2sinωtcosφ + 2cosωtsinφ = 2sin (ωt + φ)

If the coefficient indicated as "2" in the above equation is replaced with a constant K determined according to various conditions, it can be expressed as Y = Ksin (ωt + φ). Here, since the phase φ of the reluctance change corresponds to the relative linear position of the rod portion, the linear position is detected by measuring the phase shift φ of the output signal Y with respect to the primary AC signal sinωt (or cosωt). be able to.

Output composite signal Y of the secondary coil and reference signal s
The means for obtaining the phase shift φ from inωt (or cosωt) can be appropriately configured. FIG. 26 is a diagram showing an example of a circuit in which the phase shift φ is calculated by a digital amount. In particular, although not shown, a reference AC signal sinωt and an output signal Y = Ksin (ωt +
By obtaining the time difference of 0 phase from θ), the phase shift φ can also be obtained as an analog amount.

In FIG. 26, the oscillator 32 is a circuit for generating the reference sine signal sinωt and the cosine signal cosωt, and the phase difference detection circuit 37 is a circuit for measuring the phase shift φ. The clock pulse CP transmitted from the clock oscillator 33 is counted by the counter 30. Counter 30
Is, for example, modulo M (M is an arbitrary integer), and the count value is given to the register 31. From the 4 / M frequency-divided output of the counter 30, a pulse Pc obtained by frequency-dividing the clock pulse CP by 4 / M is extracted and applied to the C input of the 1/2 frequency-division flip-flop 34. A pulse Pb output from the Q output of the flip-flop 34 is added to the flip-flop 35, a pulse Pa output from the / Q output is added to the flip-flop 36, and outputs of these 35 and 36 are low-pass filters 38 and 39 and an amplifier 40, respectively. A cosine signal cos ωt and a sine signal sin ωt are obtained via 41 and applied to the primary coils 1A to 1D of the phases A to D, respectively.
The M count in the counter 30 is the reference signal cos.
This corresponds to a phase angle of 2π radians of ωt and sinωt.
That is, one count value of the counter 30 indicates a phase angle of 2π / M radian.

The combined output signal Y of the secondary coils 2A to 2D is applied to a comparator 43 via an amplifier 42, and a square wave signal corresponding to the positive / negative polarity of the signal Y is added to the comparator 4.
It is output from 3. In response to the rise of the output signal of the comparator 43, the rise detection circuit 44 outputs a pulse Ts, and the count value of the counter 30 is loaded into the register 31 in response to the pulse Ts. As a result, the digital value Dφ corresponding to the phase shift φ is taken into the register 31. In this way, it is possible to obtain the data Dφ that indicates the linear position within the predetermined range P by absolute. The signal processing method is not limited to the phase shift method as described above, and the differential output of the secondary coil may be rectified to obtain an analog voltage at a level corresponding to the linear position, like a normal differential transformer. Good. In that case, the coil portion may have only one of the A and C phases or the B and D phases.

Rod portions 6, 15, 16, 17, 22, 45, 46, 51 shown in FIGS. 1, 3, 11, 14, 14, 15, 16, 19, 22, and 24. (In other words, the rod portion of the type in which the conductor portion is attached to the surface of the central rod or the substrate member in a predetermined pattern) has a simple manufacturing process and can be provided at low cost by mass production. FIG. 27 is a flow chart showing an example of a manufacturing process of such a rod portion. First, the entire surface (flat plate shape) of a long base material (corresponding to the central rod 6a or the substrate members 15a to 51a) is formed. One is provided with a predetermined conductive substance on only one side or both sides by a predetermined surface treatment technique (eg, plating, thermal spraying, baking, painting, etc.). Next, the unnecessary portion of the conductive material is removed by etching or another technique, and the predetermined conductor portions 6b and 15 are removed.
The patterns b to 51b are formed. Next, if necessary, surface coating is performed with a substance corresponding to the filler 3 in FIG. Finally, cut the completed long rod part to the required length.

FIG. 28 is a flow chart showing another example of the manufacturing process of the rod portion. In this example, a predetermined surface processing technique (for example, thermal spraying, baking, etc.) is formed on the surface of a long base material in a predetermined pattern from the beginning. ), A conductive substance is attached, and thereafter, the same process as in FIG. 27 is performed.

The present invention can also be applied to an absolute linear position detecting device as shown in Japanese Patent Application No. 57-188865 (Japanese Patent Laid-Open No. 59-79114). Such an absolute linear position detecting device is
A plurality of linear position detecting devices having different lengths are provided side by side, and the absolute linear position exceeding the range of P is detected by calculation using the deviation of the values of the respective linear position detection data. For example, when two linear position detection devices having different lengths of P (one is P1 and the other is P2) are installed side by side, as shown in FIG.
The flat rod portions 60 and 61 can be configured by 2 respectively. FIG. 29 is a plan view showing an example in which two linear position detecting devices as shown in FIGS. 11 to 13 are provided side by side, and 60b and 61b are conductor portions of the rod portions 60 and 61, and A to A. D is a coil portion including a core, a primary coil, and a secondary coil corresponding to the phases A to D. The formation of the pattern of the conductor portion for the plurality of detection devices on the common base material can be extremely easily performed by the manufacturing process as shown in FIGS. 27 and 28. Therefore, the present invention brings various advantages such as ease of manufacture and cost reduction even in such an absolute linear position detecting device. The primary coil and the secondary coil do not necessarily have to be provided separately, and may be common as shown in Japanese Utility Model Laid-Open No. 58-2621 or Japanese Utility Model Laid-Open No. 58-39507.

[0035]

As described above, according to the present invention, the conductor portion is attached to the rod portion base material in a predetermined pattern by using an appropriate surface processing technique. The process can be simplified and the manufacturing cost can be expected to be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a linear position detecting device manufactured by a manufacturing method of the present invention.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is a vertical cross-sectional view showing a modified example of the rod portion of FIG.

FIG. 4 is a vertical cross-sectional view showing another embodiment of the rod portion in FIG.

5 is a vertical sectional view showing still another embodiment of the rod portion in FIG.

6 is a longitudinal sectional view showing another embodiment of the rod portion in FIG.

FIG. 7 is a vertical cross-sectional view showing a modification of FIG.

FIG. 8 is a vertical sectional view showing another embodiment of the linear position detecting device manufactured by the manufacturing method of the present invention.

FIG. 9 is a longitudinal sectional view showing still another embodiment of the linear position detecting device manufactured by the manufacturing method of the present invention.

10 is a cross-sectional view taken along the line XX of FIG.

FIG. 11 is a vertical sectional view showing still another embodiment of the linear position detecting device manufactured by the manufacturing method of the present invention.

12 is a plan view of the flat rod portion of FIG.

13 is a sectional view taken along the line XIII-XIII in FIG.

FIG. 14 is a plan view showing another embodiment of the linear position detecting device manufactured by the manufacturing method of the present invention.

FIG. 15 is a plan view showing still another embodiment of the linear position detecting device manufactured by the manufacturing method of the present invention.

FIG. 16 is a vertical sectional view showing another embodiment of the linear position detecting device manufactured by the manufacturing method of the present invention.

17 is a plan view of the flat rod portion in FIG.

18 is a sectional view taken along the line VIII-VIII of FIG.

FIG. 19 is a longitudinal sectional view showing another embodiment of the linear position detecting device manufactured by the manufacturing method of the present invention.

20 is a plan view of the flat rod portion in FIG.

21 is a sectional view taken along the line IIXI-IIXI of FIG.

FIG. 22 is a partial cross-sectional side view showing still another embodiment of the linear position detecting device manufactured by the manufacturing method of the present invention.

FIG. 23 is a sectional view taken along the line IIXIII-IIXIII of FIG.

FIG. 24 is a partial cross-sectional side view showing another embodiment of the linear position detecting device manufactured by the manufacturing method of the present invention.

25 is a cross-sectional view taken along the line VV of FIG.

FIG. 26 is an electrical block diagram showing an example of a circuit for measuring the electrical phase shift amount according to the detected linear position in the linear position detection device manufactured by the manufacturing method of the present invention.

FIG. 27 is a flowchart showing an example of a manufacturing process of the rod portion of the linear position detecting device according to the manufacturing method of the present invention.

FIG. 28 is a flowchart showing another embodiment of the manufacturing process of the rod portion.

FIG. 29 is a plan view showing another embodiment of the linear position detecting device according to the manufacturing method of the present invention, showing an example in which two linear position detecting devices are provided for absolute linear position detection.

[Explanation of symbols]

1A to 1D ... primary coil, 2A to 2D ... secondary coil,
4, 5 ... Magnetic coil case, 6, 7, 8, 9 ... Round rod-shaped rod portion, 15, 16, 17, 22, 45, 60,
61 ... Plate-shaped rod portion, 46, 51 ... Helical rod portion, 6b, 7b, 8b, 9b, 15b, 16b, 17
b, 22b, 45b, 60b, 61b, 46b, 51b
... Conductor portion 11-14, 18-21, 47-50,
52-59 ... Core of each phase coil portion, 6a, 46a, 51
a, ... central rods, 15a, 16a, 17a, 22a,
45a, 62 ... A substrate member common to a plurality of rod parts.

Claims (2)

[Claims] 1. A coil unit having at least two primary coils, each of which is excited by a primary AC signal having a phase difference from each other, and a secondary coil corresponding to the primary coil,
A conductor portion provided so as to be linearly displaceable relative to the coil portion, and the rod portion is provided so as to form an eddy current path for the magnetic flux generated by the coil portion. Are repeatedly provided at predetermined intervals along the relative linear displacement direction, and the conductor portion is made of a weakly magnetic or non-magnetic material and is relatively more than the material of other portions of the rod portion. By arranging the primary coil and the secondary coil such that the correspondence between the primary coil and the conductor portion of the rod portion is deviated between the primary coils. A signal obtained by phase-shifting the primary AC signal according to the relative linear position of the rod portion is obtained on the side of the secondary coil, and the phase shift amount is the arrangement of the conductor portions in the rod portion. 1 repetition of A method of manufacturing the rod portion in a linear position detecting device, characterized in that the arrangement of the coil portion is determined so as to correspond to an electrical angle of 360 degrees for a linear displacement amount corresponding to an icicle. It is deposited on the substrate whole surface a predetermined conductive material, then the Remove-out unnecessary portions leaving the conductive material deposited on said substrate in a predetermined pattern, is remaining conductive material
To be the conductor portion, and thereafter, to have a lower conductivity or a lower conductivity than the conductive material.
Conductive and non-magnetic or weakly magnetic
A method for manufacturing a rod portion in a linear position detecting device, characterized by comprising coating the surface of the rod portion. 2. The method of manufacturing a rod portion in a linear position detecting device according to claim 1, wherein the attaching is performed by plating, and the removing is performed by etching.