JP2016205854A - Linear gauge sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear gauge sensor with which it is possible to easily adjust a measurement resolution.SOLUTION: A linear gauge sensor 1 comprises a scale member 8 secured to a spindle 4 and provided in a pattern having contiguous slits with a prescribed pitch distance P, and a detection element 9 for detecting a movement in a direction perpendicular to the direction of the slits among movements of the pattern and secured in a prescribed relative direction to the direction of the slits, the pattern of the slits being provided in a direction inclined by an angle θ (0°<θ<90°) from a direction perpendicular to the movement direction of the scale member 8.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a linear gauge sensor.

2. Description of the Related Art Conventionally, a linear gauge sensor that measures the displacement of a spindle by detecting a transmitted light of light irradiated on a scale member such as a slit glass fixed to the spindle is known (for example, see Patent Document 1). ).
There is also known a linear gauge sensor that measures the displacement of the spindle by alternately forming a pattern of a reflective portion and a non-reflective portion on a scale member and detecting reflected light of irradiated light by a detection element.

JP 2011-123022 A

However, the pitch distance of the slit pattern provided in the scale member is limited by the specification determined by the detection element. For this reason, the measurement resolution of the linear gauge sensor is the pitch distance, or a value obtained by dividing the pitch distance by an integer or a value obtained by multiplying by an integer.
Therefore, there is a limit in adjusting the resolution, and it has been difficult to realize a resolution of different unit systems, for example, an arbitrary magnification that is not an integral multiple.

  An object of this invention is to provide the linear gauge sensor which can adjust measurement resolution easily.

  The linear gauge sensor according to the present invention is fixed to a moving body, and is fixed in a predetermined relative direction with respect to the direction of the slit, and a scale member provided in a pattern in which slits are continuous at a predetermined pitch distance P, A detection element that detects a movement amount in a direction perpendicular to the direction of the slit among the movement amount of the pattern, and the slit pattern has an angle θ (0) from a direction perpendicular to the movement direction of the scale member. It is provided in an inclined direction (0 ° <θ <90 °).

  The slit may be provided at an angle θ = arccos (P / L) with respect to the required measurement resolution L.

  The measurement resolution L may be set to be equal to or longer than the movable range of the moving body.

  The scale member is provided with a pattern in which light reflecting portions and non-reflecting portions are alternately continued at the predetermined pitch distance as the slit, and the detection element is configured to calculate the amount of movement of reflected light from the scale member, Detection may be performed in units of the predetermined pitch distance.

  The scale member is provided with a pattern in which light transmitting portions and non-transmitting portions are alternately and alternately arranged at the predetermined pitch distance as the slit, and the detection element is configured to determine a movement amount of transmitted light from the scale member, Detection may be performed in units of the predetermined pitch distance.

    The scale member is provided with a magnetic output pattern at the predetermined pitch distance as the slit, and the detection element detects the amount of movement of the magnetic stripe from the scale member in units of the predetermined pitch distance. Also good.

  According to the present invention, the measurement resolution in a linear gauge sensor can be easily adjusted.

It is a 1st figure which shows the structure of the linear gauge sensor which concerns on 1st Embodiment. It is a 2nd figure which shows the structure of the linear gauge sensor which concerns on 1st Embodiment. It is a schematic diagram explaining the principle which a detection element detects the movement amount of the scale member which concerns on 1st Embodiment. It is a figure which shows arrangement | positioning of the scale member which provided the conventional slit pattern, and a detection element. It is a figure which shows arrangement | positioning of the scale member which provided the slit pattern which concerns on 1st Embodiment, and a detection element. It is a figure which shows the relationship between the movement amount detected in the detection element which concerns on 1st Embodiment, and the movement amount of a scale member. It is a figure which shows the slit pattern which concerns on 2nd Embodiment.

[First Embodiment]
The first embodiment of the present invention will be described below.
In this embodiment, an optical reflective linear gauge sensor 1 will be described.

FIG.1 and FIG.2 is a figure which shows the structure of the linear gauge sensor 1 which concerns on this embodiment.
The linear gauge sensor 1 includes a main body 2, a product holding unit 3 fixed to the main body 2, a spindle 4 that is supported by the product holding unit 3 and movable in the axial direction, and a measurement object fixed to one end of the spindle 4. A contact portion 5, a slit fixing portion 6 fixed to the other end of the spindle 4, one end fixed to the main body 2, and the other end fixed to the slit fixing portion 6, and the slit fixing portion 6 attached in the direction of the measurement object contact portion 5. And a spring 7 for energizing.

  Furthermore, the linear gauge sensor 1 includes a scale member 8 fixed to the slit fixing portion 6, a detection element 9, a substrate 10 including the detection element 9, and an output cable 11 that outputs a signal from the substrate 10. .

  A dustproof / waterproof cover 12 is provided at the end of the product holding portion so as to cover the spindle 4. The linear gauge sensor 1 is covered with a cover 13 and attached to a fixing jig by a product fixing hole 14.

  In such a configuration, when the spindle 4 moves in the axial direction with respect to the main body 2 in a state where the measurement object contact portion 5 is in contact with the object, the spindle 4 is fixed to the spindle 4 via the slit fixing portion 6. The scale member 8 also moves in the axial direction. The linear gauge sensor 1 measures the displacement of the object by the detection element 9 detecting the amount of movement of the scale member 8.

  FIG. 3 is a schematic diagram for explaining the principle by which the detection element 9 detects the amount of movement of the scale member 8 in the linear gauge sensor 1 according to the present embodiment.

  The detection element 9 is realized by a single IC, and includes a light source 91 (for example, LED: Light Emitting Diode), a fixed slit 92, and a light receiving unit 93 (for example, PD: Photodiode) that receives light transmitted through the fixed slit 92. With.

  The scale member 8 is provided with a slit-like pattern in which light reflecting portions and non-reflecting portions are alternately continued. For this reason, a part of the light emitted from the light source 91 is reflected by the reflecting portion of the scale member 8 and reaches the fixed slit 92.

  In the fixed slit 92, reflection portions and non-reflection portions (transmission portions) are alternately and continuously provided at the same pitch distance as the slit pattern of the scale member 8. Therefore, when the scale member 8 is moved relative to the fixed slit 92 in the left-right direction in the drawing, the amount of light detected by the light receiving unit 93 is periodically changed and light and dark are repeated.

  Specifically, the light does not reach the light receiving portion 93 when the scale member 8 is at the position (a), but the light reaches the light receiving portion 93 when the scale member 8 is moved by a 1/2 pitch (P) to the position (b). By counting the number of repetitions, it is possible to measure the amount of movement with the pitch distance as the resolution.

FIG. 4 is a diagram showing the arrangement of the scale member 8 and the detection element 9 provided with a conventional slit pattern.
A slit pattern of a reflective part and a non-reflective part is provided in a direction perpendicular to the moving direction of the scale member 8. The detection element 9 is fixed so that a predetermined relative direction with respect to the direction of the slit of the scale member 8, that is, the direction of the slit of the scale member 8 and the direction of the fixed slit 92 substantially coincide. The substantially coincidence is coincidence with accuracy capable of detecting a change in the amount of reflected light accompanying the movement of the scale member 8, and may include an error within a predetermined angle (for example, 10 °).

  In this case, since the repeated distance L1 of the slit pattern in the movement direction of the scale member 8 is equal to the pitch distance P of the fixed slit 92, the movement amount detected by the detection element 9 is equal to the movement amount of the scale member 8. In addition, the pitch distance P becomes the measurement resolution.

FIG. 5 is a diagram showing the arrangement of the scale member 8 and the detection element 9 provided with the slit pattern of the present embodiment.
Compared with the conventional slit pattern (FIG. 4), the direction of the slit of this embodiment is provided in a direction inclined by an angle θ with respect to the direction perpendicular to the moving direction of the scale member 8.

  At this time, the pitch distance P in the vertical direction and the slit in which the reflective part and the non-reflective part repeat is the same as the conventional one. As a result, the repeated distance L2 of the slit pattern in the moving direction of the scale member 8 is longer than the pitch distance P.

  For simplification of description, the size of the fixed slit 92 and the pitch distance (= P) in the detection element 9 are equally illustrated, but the present invention is not limited to this. The pitch distance is further shorter than the size of the detection element 9, and a large number (for example, several tens) of the fixed slits 92 may be provided.

  When the slit pattern of the present embodiment is used, the detection element 9 is fixed while being inclined by a predetermined relative direction with respect to the slit direction of the scale member 8, that is, the same angle θ as the slit direction. Note that an error (for example, 10 °) with an accuracy capable of detecting a change in the amount of reflected light accompanying the movement of the scale member 8 is allowed.

  With this arrangement, the slit pattern viewed from the detection element 9 has the same direction and pitch distance as those required by the specifications of the detection element 9. Further, when the scale member 8 moves in the axial direction, the pattern drawn by the slit pattern viewed from the detection element 9, that is, the movement of the reflected light detected by the detection element 9 is the same as the conventional one. Thereby, the detection element 9 detects the movement amount in the direction perpendicular to the direction of the slit among the movement amounts of the slit pattern accompanying the movement of the scale member 8.

  FIG. 6 is a diagram illustrating the relationship between the amount of movement detected by the detection element 9 according to the present embodiment and the amount of movement of the scale member 8.

In FIG. 6A, when the scale member 8 is viewed from the detection element 9, the point A on the scale member 8 is directed in the direction of the arrow inclined by the angle θ from the horizontal direction in the drawing as the scale member 8 moves. Moving.
For this reason, in FIG. 6B, when the point A moves by the repetition distance L2 of the slit pattern, the point A actually moves to the point B. However, since all the points move in parallel and the slit direction does not change, the point A apparently moves to the point C in the same moving direction (horizontal direction) as before, and the slit pattern is perpendicular to the slit direction. Move to. For this reason, the detection element 9 can detect the movement amount of the slit pattern as in the conventional case.

  When the detection element 9 detects a movement amount of one pitch distance (= P), the movement amount of the scale member 8 is such that the relationship between the conventional L1 (= P) and the L2 of this embodiment is “L1 = L2 × cos θ”. It becomes. That is, by adjusting the angle θ between 0 ° and 90 °, the detection resolution of the moving amount of the scale member 8 becomes a longer distance (L1 <L2) than before.

When it is desired to set the measurement resolution to L2, the inclination angle θ of the slit is calculated using an arc cosine function.
θ = arccos (L1 / L2)
Is required.
For example, when the pitch distance which is the measurement resolution of the detection element 9 is P = 20 μm, in order to realize the resolution of the movement amount L2 of the scale member 8 = 40 μm, the inclination angle θ = arccos (20/40) = A 60 ° slit pattern may be provided.

According to this embodiment, in the linear gauge sensor 1, the slit of the scale member 8 is provided in a direction inclined by an angle θ from the direction perpendicular to the moving direction, and the detection element 9 has the same inclination angle θ of the slit. Fixed according to the angle.
Therefore, the linear gauge sensor 1 can realize an arbitrary measurement resolution L2 longer than the pitch distance P without changing the specification of the detection element 9. Thereby, the measurement resolution in the linear gauge sensor 1 can be easily adjusted.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described.
In addition, the same code | symbol is attached | subjected about the structure similar to 1st Embodiment, and description is abbreviate | omitted or simplified.

  The linear gauge sensor 1 of the present embodiment detects the absolute position of the scale member 8 in the movable range by detecting the amount of movement of the reflected light within the pitch distance range required by the specification of the detection element 9.

  FIG. 7 is a diagram showing the arrangement of the scale member 8 and the detection element 9 provided with the slit pattern of the present embodiment.

  In the present embodiment, the angle θ of the slit provided in the scale member 8 is set near 90 °. Specifically, the period (measurement resolution) in which the reflecting portion and the non-reflecting portion appear in the moving direction of the scale member 8 is set to be greater than or equal to the movable range L3 of the scale member 8. In this case, with respect to the maximum movement amount L3 of the scale member 8, the movement amount of the reflected light detected by the detection element 9 is equal to or less than the pitch distance P required by the specification of the detection element 9.

Here, when the detection element 9 can output two signals of A phase and B phase having a phase difference of 90 degrees from each other, the linear gauge sensor 1 can acquire two signals of sin α and cos α. The linear gauge sensor 1 obtains tan ⁻¹ (−180 ° ≦ α ≦ 180 °) from these signals, thereby detecting not only the movement amount from the initial position but also the absolute position within the movable range of the scale member 8. it can.
Further, the absolute position is detected as the period approaches the movable range L3 of the scale member 8, that is, as the movement amount of the reflected light detected by the detection element 9 with respect to the maximum movement amount of the scale member 8 approaches the pitch distance P. Improvement in accuracy can be expected.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to embodiment mentioned above. Further, the effects described in the present embodiment are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the present embodiment.

  In the above-described embodiment, the optical reflection type linear gauge sensor 1 has been described. However, the configuration for adjusting the measurement resolution in this embodiment can be applied to other types of sensors.

  For example, the linear gauge sensor is provided with a pattern in which light transmitting portions and non-transmitting portions are alternately and continuously arranged at a predetermined pitch distance as a slit of the scale member, and the amount of movement of transmitted light from the scale member in the detection element is An optical transmission type detecting in units of pitch distance may be used.

  The linear gauge sensor is a magnetic type in which a magnetic output pattern is provided at a predetermined pitch distance as a slit of the scale member, and the amount of movement of the magnetic fringes from the scale member in the detection element is detected in units of the pitch distance. May be.

  In the above-described embodiment, the detection element 9 includes the fixed slit 92. However, the present invention is not limited to this. For example, the light receiving portion may be a detection element that is arranged in a comb shape at a pitch distance corresponding to the non-reflecting portion of the fixed slit and does not include the fixed slit.

1 Linear gauge sensor 4 Spindle 8 Scale member 9 Detection element

Claims (6)

A scale member fixed to the moving body and provided in a pattern in which slits are continuous at a predetermined pitch distance P;
A linear gauge sensor comprising: a detection element that is fixed in a predetermined relative direction with respect to a direction of the slit and detects a movement amount in a direction perpendicular to the direction of the slit among the movement amount of the pattern. ,
The slit pattern is a linear gauge sensor provided in a direction inclined by an angle θ (0 ° <θ <90 °) from a direction perpendicular to the moving direction of the scale member.   The linear gauge sensor according to claim 1, wherein the slit is provided at an angle θ = arccos (P / L) with respect to the required measurement resolution L.   The linear gauge sensor according to claim 2, wherein the measurement resolution L is set to be equal to or longer than a movable range of the moving body. The scale member is provided with a pattern in which light reflecting portions and non-reflecting portions are alternately continued at the predetermined pitch distance as the slit,
The linear gauge sensor according to any one of claims 1 to 3, wherein the detection element detects a movement amount of reflected light from the scale member in units of the predetermined pitch distance. The scale member is provided with a pattern in which light transmitting portions and non-transmitting portions are alternately continued at the predetermined pitch distance as the slit,
The linear gauge sensor according to any one of claims 1 to 3, wherein the detection element detects a movement amount of transmitted light from the scale member in units of the predetermined pitch distance. The scale member is provided with a magnetic output pattern at the predetermined pitch distance as the slit,
The linear gauge sensor according to any one of claims 1 to 3, wherein the detection element detects a movement amount of the magnetic stripe from the scale member in units of the predetermined pitch distance.

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