JP5193175B2 - Linear scale - Google Patents

Description

  The present invention relates to an induct thin type linear scale.

  The inductive linear scale has a slider and a scale. The slider and the scale are arranged to face each other, the coil provided on the slider and the coil provided on the scale face each other with a small gap, and an AC voltage of SIN wave / COS wave is applied to one coil. Then, by passing an excitation current, a change in voltage induced in the other coil by the electromagnetic induction action is taken out and position detection is performed.

  The linear scale is used to detect the amount of linear movement of a moving body (table of a machine tool, etc.). If the moving distance of the moving object is long, a long stroke scale that matches the moving distance is used. Must be used.

  FIG. 10 shows the configuration of a conventional long stroke scale. As shown in the figure, conventionally, when a long stroke scale is required, a plurality of short (for example, 1 m) stroke scales 1 (such a single scale is also referred to as a single scale) are arranged in a line. The coil 2 provided in each single scale 1 is connected in series. Thus, a group of a plurality of single scales 1 can be regarded as one long stroke scale 10 (such a scale is also referred to as a combination scale). The output of the combination scale 10 is input to the preamplifier 4 via the connector 3.

  However, when a long stroke combination scale is configured by series connection, C (capacitor: stray capacitance) components and L (inductance) components distributed on the scale increase. And, in the specification, when a combination scale having a long stroke exceeding a stroke of 4 m, for example, is configured by series connection, the C component and L component of the scale increase excessively, and the waveform of the applied voltage is induced by this. The phase shift (phase difference) from the waveform of the applied voltage becomes too large and phase inversion occurs, so that a count error occurs in the A / D converter that processes the induced voltage and the movement amount is accurately detected. Will not be able to. This is particularly noticeable when the frequency of the excitation current is high.

For this reason, for example, when a combination combination scale having a long stroke exceeding 4 m is formed, grouping wiring is used.
For example, in the case of composing an 11 m long stroke combination scale, as shown in FIG. 11, two single scales 1 are connected in series to form a 4 m long stroke combination scale 5, two groups and three groups. The single scale 1 is connected in series, and a group of 3 m long stroke combination scales 6 is arranged in a row, and the coils 2 of these combination scales 5 and 6 are connected in parallel. By doing so, it can be regarded as a combination scale 20 of one long stroke having a length of 11 m. The output of the combination scale 20 is input to the preamplifier 4 via the connector 3.

  Further, since the single scale 1 is insufficient in the combination scale 6 as compared with the combination scale 5, a resistor 7 having a resistance value corresponding to the resistance value of one single scale 1 is attached to the linear scale. At the site, it was connected to the output terminal of the combination scale 6 so that the resistance of the combination scale 5 and the combination scale 6 would be the same.

JP 9-32502 A

  However, when the combination scales 5 and 6 are simply connected in parallel as shown in FIG. 11, a large bundle of wirings 21 is generated, and it may be difficult to secure a physical space in which this can be arranged. there were.

  In FIG. 11, the difference in the number of scales between groups is one, but the difference in the number of scales between groups may be two or three due to the difference in stroke. Therefore, it is necessary to select a resistor having a resistance value corresponding to the difference in the number of scales and to provide the resistor in a group where the single scale 1 is insufficient, and the installation work is troublesome.

  Further, conventionally, it is necessary to perform operations such as driving a pin (terminal) into the single scale 1, crimping a lead wire to the implanted pin, and wiring the crimped lead wire at the installation site of the linear scale. Therefore, it took time to install the scale and it was easy to make wiring mistakes.

  Therefore, in view of the above circumstances, the present invention provides a linear scale capable of reducing the physical space required for wiring of the combination scale and facilitating the installation work of the combination scale in the field. And

The linear scale of the first invention that solves the above problems is a linear scale comprising a slider and a combination scale,
The combination scale has a plurality of single scales arranged in a row and a common line, and by connecting the single scale coils to the common line, all the single scale coils are arranged in parallel. Configuration,
For the plurality of single scales, a plurality of types of single scales having different lengths are used,
In addition, an impedance matching component is connected to each of the plurality of types of single-scale coils having different lengths to match the plurality of types of single-scale impedances having different lengths.
The linear scale of the second invention is a linear scale comprising a slider and a combination scale,
The combination scale has a plurality of single scales arranged in a row and a common line, and by connecting the single scale coils to the common line, all the single scale coils are arranged in parallel. Configuration,
The common line is formed by connecting a plurality of the divided common lines by connecting the connectors using a divided common line provided with connectors at both ends,
The single-scale coil is connected to each divided common line,
For the plurality of single scales, a plurality of types of single scales having different lengths are used,
In addition, an impedance matching component is connected to each of the plurality of types of single-scale coils having different lengths to match the plurality of types of single-scale impedances having different lengths.

The linear scale of the third invention is the linear scale of the first or second invention,
Each of the impedance matching components connected to the plurality of types of single-scale coils of different lengths is a resistor having the same resistance value,
The resistor has a resistance value having a negligible magnitude of the difference in impedance between the single scales of different lengths.

The linear scale of the fourth invention is the linear scale of the first or second invention,
Each of the impedance matching components connected to the plurality of types of single-scale coils of different lengths is a combination of any one of a resistor, an inductor, and a capacitor, and has the same combined impedance value. And
In addition, the combination of any one of the resistor, the inductor, and the capacitor has a combined impedance value that is large enough to ignore the impedance difference between the plurality of types of different single scales. Features.

The linear scale of the fifth invention is the linear scale of the first or second invention,
Each of the impedance matching components connected to the plurality of types of single-scale coils of different lengths is a resistor having the same resistance value,
The resistor has a resistance value that is 100 times or more the impedance difference between the single scales of different lengths.

The linear scale of the sixth invention is the linear scale of the first or second invention,
Each of the impedance matching components connected to the plurality of types of single-scale coils of different lengths is a combination of any one of a resistor, an inductor, and a capacitor, and has the same combined impedance value. And
In addition, a combination of any one of the resistor, the inductor, and the capacitor has a composite impedance value that is 100 times or more the impedance difference between the plurality of types of single scales having different lengths. To do.

According to the linear scale of the first or second aspect of the invention, the linear scale includes a slider and a combination scale, and the combination scale includes a plurality of single scales arranged in a row and a common line. And having a configuration in which all the single-scale coils are connected in parallel by connecting the single-scale coils to the common line, no matter how long the combination scale is, The phase shift between the waveform of the applied voltage and the waveform of the induced voltage does not increase. In addition, the conventional pin group wiring is not required, and a large bundle of wiring generated by simple parallel connection does not occur. For this reason, the physical space required for wiring of the combination scale can be reduced, wiring work is easy, and wiring errors are less likely to occur.

According to the linear scale of the second invention, the pre-Symbol common line, using the divided common line having a connector at both ends, which formed by a plurality of connecting the dividing common line by coupling the connectors The single-scale coil is characterized in that it is connected to each divided common line, so that the wiring work can be performed simply by connecting the connectors of the divided common line to each other. Since no connection work is required, the wiring work is further facilitated and wiring errors are less likely to occur.

According to the first or the linear scale of the second invention, the single-scale pre-Symbol plural, uses a single scale of several different lengths, and, in a single scale of the plurality of types of different lengths each coil by connecting the impedance matching part, because it is characterized in that to match the impedance of a single scale of the plurality of types of different lengths, without having to worry about the difference between the impedance, different lengths the single of Since a combination scale having a desired length can be configured by arbitrarily combining the scales, the installation work of the combination scale at the site is facilitated.

According to the linear scale of the third invention, in the linear scale of the first or second invention, the impedance matching components connected to the plurality of types of single-scale coils of different lengths all have the same resistance value. And the resistor has a resistance value with a negligible magnitude of the impedance difference between the single scales of different lengths of the plurality of types. (3) The same effect as that of the invention can be obtained, and there is no need to provide impedance matching parts (resistances) having different resistance values for each single scale having different lengths when manufacturing a single scale with impedance matching parts (resistances). Single scale production is very easy.

According to the linear scale of the fourth invention, in the linear scale of the first or second invention, each of the impedance matching components connected to the plurality of types of single-scale coils of different lengths includes a resistor and an inductor. And a combination of any one of the plurality of resistors, inductors and capacitors, which have the same combined impedance value, Since it has a composite impedance value that can ignore the impedance difference between the single scales, the same effect as the third invention can be obtained, and the impedance matching component (resistance and inductor) When manufacturing a single scale with a combination of a capacitor and a capacitor) Different synthetic impedance values of the impedance matching components (a combination of either a plurality of resistors and an inductor and a capacitor) is not necessary to provide a per scale, production of single scale is very easy.

According to the linear scale of the fifth invention, in the linear scale of the first or second invention, the impedance matching components connected to the plurality of types of single-scale coils of different lengths all have the same resistance value. And the resistor has a resistance value that is at least 100 times the impedance difference between the single scales of the different types of different lengths. In addition, when manufacturing a single scale with impedance matching components (resistors), there is no need to provide impedance matching components (resistors) with different resistance values for each single scale having a different length. Scale production is very easy.

According to the linear scale of the sixth aspect of the present invention, in the linear scale of the first or second aspect , the impedance matching components connected to the plurality of types of single-scale coils of different lengths are both resistors and inductors. And a combination of any one of the plurality of resistors, inductors and capacitors, which have the same combined impedance value, Since it has a composite impedance value that is 100 times or more the impedance difference between single scales, the same effect as the third invention can be obtained, and impedance matching components (resistors, inductors and capacitors) When manufacturing a single scale with a combination of any of the above, single scales with different lengths Different synthetic impedance values of the impedance matching components (a combination of either a plurality of resistors and an inductor and a capacitor) is not necessary to provide a per le, production of single scale is very easy.

It is a block diagram of the feedback control apparatus of the full closed loop using the linear scale which concerns on Example 1 of this invention. It is a block diagram of the combination scale in the linear scale which concerns on Example 1 of Embodiment of this invention. (A) is a block diagram of a single scale that is a component of the combination scale, and (b) is a block diagram of another single scale that is a component of the combination scale. It is a block diagram of the combination scale in the linear scale which concerns on Example 2 of Embodiment of this invention. (A) is a block diagram of a single scale that is a component of the combination scale, and (b) is a block diagram of another single scale that is a component of the combination scale. It is a block diagram of the combination scale in the linear scale which concerns on Example 3 of Embodiment of this invention. (A) is a block diagram of a single scale that is a component of the combination scale, and (b) is a block diagram of another single scale that is a component of the combination scale. It is a block diagram of the combination scale in the linear scale which concerns on Example 4 of this invention. (A) is a block diagram of a single scale that is a component of the combination scale, and (b) is a block diagram of another single scale that is a component of the combination scale. It is a block diagram of the combination scale which carried out the conventional series connection. It is a block diagram of the combination scale which performed the conventional grouping wiring.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS.

  First, the case where the linear scale of the first embodiment is applied to a fully closed loop feedback control device in a machine tool will be described with reference to FIG.

  As shown in FIG. 1, the ball screw 31 has a screw shaft 31a and a nut 31b to be screwed together. The screw shaft 31a is connected to a rotating shaft of a drive motor 32, and the nut 31b is attached to a table 33 which is a moving body. It is attached. Accordingly, when the screw shaft 31a is rotated as indicated by the arrow A by the drive motor 32, the table 33 is moved linearly as indicated by the arrow B together with the nut 31b.

  In order to detect the position (movement amount) of the table 33, the linear scale 41 of the first embodiment is used. The inductive linear scale 41 includes a slider 42 and a combination scale 43. The slider 42 is attached to the table 33 and moves linearly together with the table 33. The combination scale 43 is a machine tool. It is attached to a fixed part (not shown). By arranging the slider 42 and the combination scale 43 so as to face each other, the coil 44 provided on the slider 42 and the coils 54 and 58 provided on the combination scale 43 face each other with a minute gap therebetween.

  The combination scale 43 has a long stroke that matches the movement distance of the table 33. Details of the configuration of the combination scale 43 will be described later.

  When an SIN wave / COS wave AC voltage is applied from the A / D converter 46 to the coil 44 of the slider 42 to cause excitation current to flow, a voltage is induced in the coils 54 and 58 of the combination scale 43 by electromagnetic induction. . The induced voltage changes according to the change in the relative position between the slider 42 (coil 44) and the combination scale 43 (coils 54, 58). The induced voltage is taken out from the combination scale 43 through the connector 47, amplified by the preamplifier 48, and then input to the A / D converter 46.

  The A / D converter 46 processes the induced voltage to detect the position (movement amount) of the table 33 and feeds back a signal of this detected position to the NC servo amplifier 49 which is a control device. The NC servo amplifier 49 controls the rotation of the drive motor 32 according to the deviation between the detected position and the command position so that the position of the table 33 becomes the command position.

  Next, the configuration of the combination scale 43 of the first embodiment will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the combination scale 43 includes a plurality of (in the illustrated example, eight) single strokes 51 (for example, 1 m) and a plurality of (in the illustrated example, two) short scales ( The single scale 52 (for example, 250 mm) is arranged in a row so that it can be regarded as a single long-stroke (for example, 8.5 m) scale.

  The single scale 51 has a configuration in which a zigzag coil 54 is provided on a base 53 which is a rectangular iron plate. Resistors 56 are connected to both sides of the coil 54 of the single scale 51. Similarly, the single scale 52 has a configuration in which a zigzag coil 58 is provided on a base 57 which is a rectangular iron plate. Resistors 56 are also connected to both sides of the coil 58 of the single scale 52. These single scales 51 and 52 are manufactured at a manufacturing factory of the linear scale 41 as a product with an impedance matching component (resistor 56) as shown in FIGS. 3 (a) and 3 (b).

  As shown in FIGS. 1 and 2, the single scales 51 and 52 can be handled as individual scales in connection by connecting the coils 54 and 58 in parallel (parallel). . However, if a simple parallel connection as shown in FIG. 11 is performed, the number of wires increases by the number of single scales 51 and 52, resulting in a large bundle of wires.

  Therefore, for the coil connection of the single scales 51 and 52, a form of multi-drop wiring used for serial bus connection is adopted. That is, by arranging a common line (bus line) 61 and connecting the coils 54 and 58 of the single scales 51 and 52 to the common line 61, the coils 54 and 58 of all the single scales 51 and 52 are connected. In parallel. A connector 47 is provided at the end of the common line 61, and this connector 47 is coupled to the connector 47 of the preamplifier 48.

  On the other hand, since the single scale 51 and the single scale 52 have different lengths (strokes), the R (resistance) component, C (capacitor: stray capacitance) component, and L (inductance) component of the single scales 51 and 52 respectively. The values are different and the impedance with respect to the frequency of the excitation current is different. Therefore, if the coils 54 and 58 of the single scales 51 and 52 having different lengths are simply connected to the common line 61, the position detection accuracy at the joint portion of the single scales 51 and 52 is deteriorated.

  Therefore, the resistor 56 described above is connected to both the coils 54 and 58 of the single scales 51 and 52 as a component (impedance matching component) for matching the impedances of the single scale 51 and the single scale 52. The resistors 56 provided in any of the single scales 51 and 52 have the same resistance value, and the impedance of the single scale 51 and the single scale 52 having different lengths (that is, the single scale in a state where the resistor 56 is not provided). The resistance value is such that the difference between the impedances 51 and 52 can be ignored. That is, the resistor 56 has a sufficiently large resistance value compared to the difference in impedance.

  In this case, it is desirable that the resistance value of the resistor 56 is 100 times or more the impedance difference between the single scales 51 and 52, and the impedance difference is 1% or less with respect to the resistance value. For example, if the impedance difference is 10Ω, the resistance value of the resistor 56 is 1 KΩ or more.

  However, if the resistance value of the resistor 56 is increased too much, the output (gain) of the combination scale 43 becomes too small, and accurate position detection cannot be performed. Therefore, the resistance value of the resistor 56 needs to be a value that does not cause the output (gain) of the combination scale 43 to become extremely small. It should be noted that how much the output is necessary may be determined as appropriate according to the output processing capability. That is, the upper limit value of the resistance value of the resistor 56 may be appropriately determined according to the required output level.

In the illustrated single scale 51, since the resistors 56 are provided on both sides of the coil 54, the combined resistance value of the resistors 56 on both sides may be set to the above value. Similarly, since the single scale 52 of the illustrated example is provided with resistors 56 on both sides of the coil 58, the combined resistance value of the resistors 56 on both sides may be set to the above value. The reason why the resistors 56 are provided on both sides of the coils 54 and 58 is to improve the stability of the AC voltage induced in the coils 54 and 58.
However, the present invention is not limited to this, and from the viewpoint of matching the impedances of the single scales 51 and 52, it is not always necessary to provide the resistors 56 on both sides of the coils 54 and 58 as described above. The resistor 56 may be provided only on one side. In this case, the resistance value of the resistor 56 provided on one side of the coil 54 may be set to the above value, and the resistance value of the resistor 56 provided on one side of the coil 58 may be set to the above value.

  As described above, according to the linear scale 41 of the first embodiment, the linear scale 41 includes the slider 42 and the combination scale 43. The combination scale 43 includes a plurality of the combination scales 43 arranged in a line. The single scales 51 and 52 and the common line 61 are connected, and the coils 54 and 58 of the single scales 51 and 52 are connected to the common line 61, respectively. Since the arrangement is parallel, no matter how long the combination scale 43 is made, the phase shift between the waveform of the applied voltage and the waveform of the induced voltage does not increase. In addition, the conventional pin group wiring is not required, and a large bundle of wiring generated by simple parallel connection does not occur. For this reason, the physical space required for the wiring of the combination scale 43 can be reduced, the wiring work is easy, and wiring errors are less likely to occur.

  Further, according to the linear scale 41 of the first embodiment, the resistors 56 are connected to the coils 54 and 58 of the single scales 51 and 52 having different lengths as impedance matching parts, respectively, so that the single scales 51 having different lengths are connected. , 52 are matched to each other, so that a combination scale having a desired length is configured by arbitrarily combining the single scales 51, 52 having different lengths without worrying about the difference in impedance. Therefore, the installation work of the combination scale 41 on the site is facilitated.

  In addition, according to the linear scale 41 of the first embodiment, the impedance matching components connected to the coils 54 and 58 of the single scales 51 and 52 having different lengths are all the resistors 56 having the same resistance value. The resistor 56 has a resistance value of a negligible magnitude (100 times or more of the impedance difference) of the impedance difference between the single scales 51 and 52 having different lengths. Therefore, when manufacturing the single scales 51 and 52 with impedance matching components (resistors 56), it is not necessary to provide impedance matching components (resistances) having different resistance values for the single scales 51 and 52 having different lengths. The production of the single scales 51 and 52 is very easy.

  In the above, the single scales 51 and 52 having two different lengths (strokes) are used. However, the present invention is not limited to this, and the single scales having three or more different lengths (strokes) (for example, 1 m) (Single scales of 500 mm and 250 mm) may be used. In this case as well, it is sufficient to connect resistors to each single-scale coil and match the impedances of all single-scales in the same manner as described above, and the resistance value of the resistors at this time ignores the difference in impedance between the single scales. It is sufficient to set the value to a value that can be obtained (100 times the impedance difference or more). In addition, when the difference in impedance between a single scale and the difference in impedance between other single scales are different, the size that allows the largest impedance difference to be ignored (more than 100 times the impedance difference) The resistance value may be set as follows.

<Embodiment 2>
Based on FIG.4 and FIG.5, Embodiment 2 of this invention is demonstrated. Note that the arrangement relationship between the slider and the combination scale in the linear scale, the application example of the linear scale, and the like are the same as those in the first embodiment (see FIG. 1), and thus the description thereof is omitted here.
The same parts as those in the combination scale (see FIGS. 2 and 3) of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, in the combination scale 71 in the linear scale of the second embodiment, the common line 61 is divided into a plurality of portions 61A (this portion is also referred to as a divided common line). Connectors 62 are provided at both ends of 61A. By connecting connectors 62 of adjacent divided common lines 61A to each other and connecting a plurality of divided common lines 61A, it can be regarded as one common line 61 (also referred to as a combination common line). .

  And the coils 54 and 58 of each single scale 51 and 52 are each connected to each division | segmentation common line 61A. The single scales 51 and 52 are linear products as products in which an impedance matching component (resistor 56) as shown in FIGS. 5A and 5B and a divided common line 61A with a connector 62 are attached. Manufactured at a scale manufacturing plant. Therefore, at the installation site of the linear scale, the wiring work is simply completed by simply connecting the connectors 62 of the adjacent divided common lines 61A. It should be noted that in the single scale 52 at the extreme end, the connector 62 of the divided common line 61A is coupled to the connector 47 of the preamplifier 48.

  The other configuration of the combination scale 71 of the second embodiment is the same as that of the combination scale 41 of the first embodiment.

  As described above, according to the linear scale of the second embodiment, the common line 61 uses the divided common line 61A in which the connectors 62 are provided at both ends, and the divided common line 61A is connected by connecting the connectors 62 to each other. Since the coils 54 and 58 of the single scales 51 and 52 are connected to the respective divided common lines 61A, the wiring work is simply a connector of the divided common line 61A. It is only necessary to couple 62, and it is not necessary to connect the coil and the common line in the field, so that the wiring work is further facilitated and wiring errors are less likely to occur.

<Embodiment 3>
A third embodiment of the present invention will be described with reference to FIGS. The arrangement relationship between the linear scale slider and the combination scale, the application example of the linear scale, and the like are the same as those in the first embodiment (see FIG. 1), and thus the description thereof is omitted here.

  As shown in FIG. 6, the combination scale 81 in the linear scale according to the third embodiment includes a plurality of (for example, eight) short strokes (for example, 1 m) and a plurality of (for example, two) single scales 82. A short scale (for example, 250 mm) single scale 83 is arranged in a row so that it can be regarded as a single long stroke (for example, 8.5 m) scale.

  The single scale 82 has a configuration in which a zigzag coil 85 is provided on a base 84 which is a rectangular iron plate. A resistor 88, an inductor 89, and a capacitor 90 are connected to both sides of the coil 85 of the single scale 82, respectively. Similarly, the single scale 83 has a configuration in which a zigzag coil 87 is provided on a base 86 which is a rectangular iron plate. A resistor 88, an inductor 89, and a capacitor 90 are connected to both sides of the coil 87 of the single scale 83, respectively.

  The single scales 82 and 83 are manufactured at a linear scale manufacturing plant as a product with impedance matching components (resistor 88, inductor 89, capacitor 90) as shown in FIGS. 7 (a) and 7 (b).

  As shown in FIG. 6, the single scales 82 and 83 can be handled as individual scales for connection by connecting the coils 85 and 87 in parallel. However, if a simple parallel connection as shown in FIG. 11 is performed, the number of wires increases by the number of single scales 82 and 83, resulting in a large bundle of wires.

  Therefore, a multi-drop wiring form used for serial bus connection is adopted for coil connection of the single scales 82 and 83. That is, by arranging a common line (bus line) 91 and connecting the coils 85 and 87 of the single scales 82 and 83 to the common line 91, the coils 85 and 87 of all the single scales 82 and 83 are connected. In parallel. A connector 94 is provided at the end of the common line 91, and this connector 94 is coupled to the connector 95 of the preamplifier 96.

  On the other hand, since the single scale 82 and the single scale 83 have different lengths (strokes), the R (resistance) component, C (capacitor: stray capacitance) component, and L (inductance) component of the single scales 82 and 83 respectively. The values are different and the impedance with respect to the frequency of the excitation current is different. Therefore, if the coils 85 and 87 of the single scales 82 and 83 are simply connected to the common line 91, the position detection accuracy at the joint portion of the single scales 82 and 83 is deteriorated.

Therefore, the resistor 88, the inductor 89, and the capacitor 90 are used as components (impedance matching components) for matching the impedances of the single scale 82 and the single scale 83 in any of the coils 85 and 87 of the single scales 82 and 83. Is connected.
The common line 91 includes a common core wire 92 and a common shield line 93 that covers the common core wire 92. For convenience of explanation, in FIG. 6, the shield line 93 is shown in a perspective view (dashed line) (the same applies to FIGS. 8 and 9 described later).

In the single scale 82, a resistor 88 and an inductor 89 are connected in series, and the coil 85 of the single scale 82 is connected to the common core wire 92 via the resistor 88 and the inductor 89. The capacitor 90 has one end connected to the coil 85 and the other end connected to the common shield line 93. Similarly, in the single scale 83, a resistor 88 and an inductor 89 are connected in series, and the coil 87 of the single scale 83 is connected to the common core wire 92 via the resistor 88 and the inductor 89. The capacitor 90 has one end connected to the coil 87 and the other end connected to the common shield wire 93.
The common shield line 93 is grounded to the circuit ground 97 via the preamplifier 96.

  In any single scale 85, 87, the resistor 88, the inductor 89, and the capacitor 90 have the same resistance value, the same inductance value, and the same capacitance value, that is, the same combined impedance value. The resistor 88, the inductor 89, and the capacitor 90 are impedances of the single scale 82 and the single scale 83 having different lengths (that is, impedances of the single scales 51 and 52 in a state where the resistor 88, the inductor 89, and the capacitor 90 are not provided). The resultant impedance value has a magnitude that can be ignored. That is, the resistor 88, the inductor 89, and the capacitor 90 have a combined impedance value that is sufficiently larger than the impedance difference.

  In this case, the value of the combined impedance of the resistor 88, the inductor 89, and the capacitor 90 is 100 times or more the difference in impedance between the single scales 51 and 52, and the difference in impedance is 1% or less with respect to the combined impedance value. It is desirable that For example, if the impedance difference is 10Ω, the combined impedance value of the resistor 88, the inductor 89, and the capacitor 90 is 1 KΩ or more.

  However, if the combined impedance value of the resistor 88, the inductor 89, and the capacitor 90 is too large, the output (gain) of the combination scale 81 becomes too small, and accurate position detection cannot be performed. Therefore, the combined impedance value of the resistor 88, the inductor 89, and the capacitor 90 needs to be set to such a value that the output (gain) of the combination scale 81 does not become extremely small. It should be noted that how much the output is necessary may be determined as appropriate according to the output processing capability. In other words, the upper limit value of the combined impedance value of the resistor 88, the inductor 89, and the capacitor 90 may be appropriately determined according to the required output level.

In the illustrated single scale 82, since the resistor 88, the inductor 89, and the capacitor 90 are provided on both sides of the coil 85, the combined impedance value of the resistor 88, the inductor 89, and the capacitor 90 on both sides is set to the above value. do it. Similarly, since the resistor 88, the inductor 89, and the capacitor 90 are provided on both sides of the coil 87 even in the single scale 83, the combined impedance value of the resistor 88, the inductor 89, and the capacitor 90 on both sides is set to the above value. Good. The reason why the resistor 88, the inductor 89, and the capacitor 90 are provided on both sides of the coils 85 and 87 is to improve the stability of the AC voltage induced in the coils 85 and 87.
However, the present invention is not limited to this, and from the viewpoint of matching the impedances of the single scales 82 and 83, it is not always necessary to provide the resistor 88, the inductor 89, and the capacitor 90 on both sides of the coils 85 and 87 as described above. The resistor 88, the inductor 89, and the capacitor 90 may be provided only on one side of the coils 85 and 87. In this case, the combined impedance value of the resistor 88, inductor 89 and capacitor 90 provided on one side of the coil 85 is set to the above value, and the combined impedance value of the resistor 88, inductor 89 and capacitor 90 provided on one side of the coil 87 is set. The value may be a value as described above.

  As described above, according to the linear scale of the third embodiment, the linear scale includes the slider and the combination scale 81, and the combination scale 81 includes a plurality of single scales arranged in a line. 82, 83 and a common line 91, and by connecting the coils 85, 87 of the single scales 82, 83 to the common line 91, respectively, the coils 85, 87 of all the single scales 82, 83 are arranged in parallel. Since the configuration is characterized, no matter how long the combination scale 81 is, the phase shift between the waveform of the applied voltage and the waveform of the induced voltage does not increase. In addition, the conventional pin group wiring is not required, and a large bundle of wiring generated by simple parallel connection does not occur. For this reason, the physical space required for wiring of the combination scale 81 can be reduced, wiring work is easy, and wiring mistakes are less likely to occur.

  Further, according to the linear scale of the third embodiment, the resistors 88, the inductor 89, and the capacitor 90 are connected as the impedance matching parts to the coils 85, 87 of the single scales 82, 83 having different lengths, respectively, so that the lengths are different. Since the impedances of the single scales 51 and 52 are matched, the single scales 82 and 83 having different lengths can be arbitrarily combined without worrying about the difference in impedance. Since the combination scale can be configured, the installation work of the combination scale at the site is facilitated.

  Further, according to the linear scale of the third embodiment, the impedance matching components connected to the coils 85 and 87 of the single scales 82 and 83 having different lengths are all the resistors 88 having the same combined impedance value. And the inductor 89 and the capacitor 90, and the resistor 88, the inductor 89 and the capacitor 90 have a negligible magnitude of a difference in impedance between the single scales 82 and 83 having different lengths (more than 100 times the impedance difference). ), When the single scales 82 and 83 with impedance matching components (resistor 88, inductor 89, capacitor 90) are manufactured, the single scales 82 and 83 having different lengths are manufactured. Impedance matching parts (resistor, inductor Data, it is not necessary to provide a capacitor), production of single scale 82 and 83 is very easy.

  In the above, the single scales 82 and 83 having two different lengths (strokes) are used. However, the present invention is not limited to this, and the single scales having three or more different lengths (strokes) (for example, 1 m) (Single scales of 500 mm and 250 mm) may be used. In this case as well, a resistor, an inductor, and a capacitor may be connected to each single scale coil in the same manner as described above to match the impedances of these single scales. Also in this case, the combined impedance value of the resistor, the inductor, and the capacitor may be a value that can ignore the impedance difference between the single scales (a value that is 100 times or more the impedance difference). When the impedance difference between a single scale and the impedance difference between other single scales are different, the largest impedance difference can be ignored (more than 100 times the impedance difference). What is necessary is just to use an impedance value.

  In the above, the impedance matching component provided on the single scale is a combination of a resistor, an inductor and a capacitor. However, the present invention is not limited to this, and the combination of the impedance matching component provided on the single scale is a combination of a resistor and an inductor. Or a combination of a resistor and a capacitor, or a combination of an inductor and a capacitor.

<Embodiment 4>
Based on FIG.8 and FIG.9, Embodiment 3 of this invention is demonstrated. Note that the arrangement relationship between the slider and the combination scale in the linear scale, the application example of the linear scale, and the like are the same as those in the first embodiment (see FIG. 1), and thus the description thereof is omitted here.
The same parts as those of the combination scale (see FIGS. 6 and 7) of the third embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 8, in the combination scale 101 in the linear scale of the fourth embodiment, the common line 91 is divided into a plurality of portions 61A (this portion is also referred to as a divided common line). In each divided common line 91A, the common core 92 is divided into a plurality of portions 92A (this portion is also referred to as a divided common core), and the common shield line 93 is divided into a plurality of portions 93A (this portion is divided into common shield lines). Also called). Connectors 102 are provided at both ends of each divided common line 91A. By connecting the connectors 102 of adjacent divided common lines 91A to each other, a plurality of divided common lines 91A are connected, so that it can be regarded as one common line 91 (also referred to as a combination common line). it can. At this time, by connecting a plurality of divided common core wires 92A, it can be regarded as one common core wire 92 (also referred to as a combined common core wire), and a plurality of divided common shield wires 93A are provided. By being connected, it can be regarded as one common shield line 93 (also referred to as a combination common shield line).

  The coils 85 and 87 of the single scales 82 and 83 are connected to the divided common lines 91A, respectively. Specifically, the coils 85 and 87 of the single scales 82 and 83 are connected to the divided common core wire 93 </ b> A via a resistor 88 and an inductor 89. The capacitor 90 has one end connected to the coils 85 and 87 and the other end connected to the divided common shield line 93A.

  The single scales 82 and 83 are provided with impedance matching components (resistor 88, inductor 89, capacitor 90) as shown in FIGS. 9A and 9B, and a divided common line 91A with a connector 102. Manufactured in a linear scale manufacturing plant as a state product. Therefore, at the installation site of the linear scale, the wiring work is simply completed by simply connecting the connectors 102 of the adjacent divided common lines 91A. It should be noted that in the single end scale 83, the connector 102 of the divided common line 91A is coupled to the connector 95 of the preamplifier 96.

  Other configurations of the combination scale 101 of the fourth embodiment are the same as those of the combination scale 81 of the third embodiment.

  As described above, according to the linear scale of the fourth embodiment, the common line 91 uses the divided common line 91A in which the connectors 102 are provided at both ends, and the divided common line 91A is connected by connecting the connectors 102 to each other. Since the coils 85 and 87 of the single scales 82 and 83 are connected to the respective divided common lines 91A, the wiring work is simply a connector of the divided common line 91A. It is only necessary to couple the wires 102, and it is not necessary to connect the coil and the common line in the field, so that the wiring work is further facilitated and wiring errors are less likely to occur.

  The present invention relates to an induct thin type linear scale, and is useful when applied to a combination scale of linear scales used for detecting the position of a moving body having a long moving distance.

31 Ball screw 31a Screw shaft 31b Nut 32 Drive motor 33 Table 41 Linear scale 42 Slider 43 Combination scale 44 Coil 46 A / D converter 47 Connector 48 Preamplifier 49 NC servo amplifier 51, 52 Single scale 53 Base 54 Coil 56 Resistance 57 Base 58 Coil 61 Common Line 61A Split Common Line 62 Connector 71, 81 Combination Scale 82, 83 Single Scale 84 Base 85 Coil 86 Base 87 Coil 88 Resistance 89 Inductor 90 Capacitor 91 Common Line 91A Split Common Line 92 Common Core 92A Split Common Core Wire 93 Common shield wire 93A Split common shield wire 94, 95 Connector 96 Preamplifier 97 Circuit ground 101 Combination scale 102 Connector

Claims (6)

A linear scale comprising a slider and a combination scale,
The combination scale has a plurality of single scales arranged in a row and a common line, and by connecting the single scale coils to the common line, all the single scale coils are arranged in parallel. Configuration,
For the plurality of single scales, a plurality of types of single scales having different lengths are used,
An impedance matching component is connected to each of the plurality of types of single-scale coils of different lengths to match the impedance of the plurality of types of single-scales of different lengths. A linear scale comprising a slider and a combination scale,
The combination scale has a plurality of single scales arranged in a row and a common line, and by connecting the single scale coils to the common line, all the single scale coils are arranged in parallel. Configuration,
The common line is formed by connecting a plurality of the divided common lines by connecting the connectors using a divided common line provided with connectors at both ends,
The single-scale coil is connected to each divided common line,
For the plurality of single scales, a plurality of types of single scales having different lengths are used,
An impedance matching component is connected to each of the plurality of types of single-scale coils of different lengths to match the impedance of the plurality of types of single-scales of different lengths. In the linear scale according to claim 1 or 2 ,
Each of the impedance matching components connected to the plurality of types of single-scale coils of different lengths is a resistor having the same resistance value,
The linear scale is characterized in that the resistor has a resistance value with a negligible magnitude of the impedance difference between the single scales of different lengths. In the linear scale according to claim 1 or 2 ,
Each of the impedance matching components connected to the plurality of types of single-scale coils of different lengths is a combination of any one of a resistor, an inductor, and a capacitor, and has the same combined impedance value. And
In addition, the combination of any one of the resistor, the inductor, and the capacitor has a combined impedance value that is large enough to ignore the impedance difference between the plurality of types of different single scales. Characteristic linear scale. In the linear scale according to claim 1 or 2 ,
Each of the impedance matching components connected to the plurality of types of single-scale coils of different lengths is a resistor having the same resistance value,
The linear scale is characterized in that the resistor has a resistance value that is 100 times or more the impedance difference between the plurality of types of single scales of different lengths. In the linear scale according to claim 1 or 2 ,
Each of the impedance matching components connected to the plurality of types of single-scale coils of different lengths is a combination of any one of a resistor, an inductor, and a capacitor, and has the same combined impedance value. And
In addition, a combination of any one of the resistor, the inductor, and the capacitor has a composite impedance value that is 100 times or more the impedance difference between the plurality of types of single scales having different lengths. Linear scale.

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