JP5601876B2 - Separate type encoder and its mounting method - Google Patents

Description

  The present invention relates to a separate type encoder and a mounting method thereof, and in particular, a separate type suitable for use in an absolute encoder having a plurality of tracks and capable of easily aligning a scale and a detector. The present invention relates to an encoder and its mounting method.

  In a linear encoder for feedback used in a machine tool or the like, an absolute encoder capable of detecting an absolute position when power is turned on is generally used.

  This absolute encoder is mainly used to detect the absolute position by combining scales with two or more tracks arranged in the lateral direction perpendicular to the measurement direction, and the positional relationship between the scale and the detector is accurate. It needs to be adjusted.

  That is, for example, in the case of an absolute encoder having two tracks, as shown in FIG. 1, the detection sensors of the scale 10 and the detector 20 have corresponding tracks 11 and 12 and detection sensors 21 and 22, respectively. 2, it is necessary that the detection sensors 21 and 22 of the tracks 11 and 12 and the scale 10 face each other in a correct state as shown in FIG. On the other hand, as shown in FIG. 3, when the positional relationship between the scale 10 and the detector 20 is deviated, for example, in the lateral direction (upward in FIG. 3), the detection sensors 21 and 22 detect the correct position. I can't.

  Therefore, especially in the case of a separate type encoder with a separate scale and detector, in order to correctly set the positional relationship between the scale and the detector when assembled in the apparatus, the processing accuracy of the mounting surface of the detector is increased, or As described in Patent Document 1, a difference in reading value between position detection track detection sensors provided for each track due to the inclination of the detector is detected, and an error due to the inclination (yawing) of the detector with respect to the scale is detected. It has been proposed to correct.

  Further, the applicant has proposed in Patent Document 2 that a tilt detecting coil is arranged on the scale side to detect and correct the tilt direction of the detector.

JP 7-324948 A JP 2008-64498 A

  However, even if the processing accuracy of the detector mounting surface is increased, mounting adjustment cannot be facilitated, and it is necessary to adjust to the optimal position mechanically while observing the signals detected on each track. Because it is unclear whether or not to shift, it took time and effort.

  On the other hand, the techniques of Patent Documents 1 and 2 each aim to make correction on the detector side even if the positional relationship (angle) of the detector fluctuates, and eliminate the need for strict positional relationship adjustment. . Therefore, none of the techniques facilitates mounting adjustment, and further, it may be possible to correct the error due to the yawing of the detector with respect to the scale, but it is not possible to correct the error due to the lateral shift. It had the problem that.

  In addition, the technique described in Patent Document 2 has a problem in that an inclination detection coil different from position detection must be arranged on the scale side.

The present invention has been made to solve the above-mentioned conventional problems, and with a relatively simple configuration using an existing track, it is possible to easily grasp the lateral displacement between the scale and the detector and adjust the mounting. The challenge is to make it easier.

The present invention relates to a separate type encoder that has a scale in which a plurality of tracks extending in the measurement direction are arranged in parallel, the scale and the detector are separated, and needs to be aligned when attached to a measurement object. In addition, a displacement amount detection sensor for detecting the plurality of tracks and detecting a displacement in a lateral direction orthogonal to the measurement direction is provided so that the displacement between the scale and the detector in the lateral direction can be displayed. It has been solved.

  Here, the deviation amount detection sensors can be provided at both ends of the detector in the measurement direction, so that the deviation in the yawing direction can be displayed.

  The deviation amount detection sensor can be a line sensor.

Further, the encoder may be an A blanking Seo absolute encoders.

According to the present invention, when the separate encoder is mounted, the scale and the detector are aligned so that the lateral displacement between the scale and the detector detected and displayed by the shift amount detection sensor is eliminated. It is intended to do.

According to the present invention, a relatively simple configuration that utilizes an existing track, the lateral displacement of the scale and detector easy simply be grasped, it is possible to perform mounting adjustment easily. In particular, when the deviation amount detection sensors are provided at both ends in the measurement direction of the detector, it is possible to grasp the deviation in the yawing direction.

Further, since the lateral displacement between the scale and the detector is quantitatively known, a margin for the mechanical attachment tolerance between the scale and the detector is known, and the attachment adjustment becomes easy.

  Further, since the margin for the mechanical mounting allowance can be confirmed, as shown in FIG. 4, the relative processing accuracy of the scale mounting surface that affects the variation in the scale running direction of the apparatus can be relaxed.

The present invention are those effective to absolute encoder requiring precision position adjustment, equally applicable to an incremental encoder.

Plan view schematically showing the configuration of the scale and detector of a 2-track absolute encoder The top view which shows the state where the detector is correctly adjusted with respect to the scale Similarly, a plan view showing a state in which the positional relationship between the scale and the detector is shifted in the lateral direction. The figure explaining the effect of this invention FIG. 2A is a plan view showing the configuration of the first embodiment of the present invention, and FIG. 2B is a diagram showing an example of an output of a deviation amount detection sensor. The figure which shows the example of a display of 1st Embodiment FIG. 5A is a plan view illustrating a configuration of a second embodiment of the present invention, and FIG. 5B is a diagram illustrating an example of an output of a deviation amount detection sensor. The block diagram which shows the structure of the detection circuit in 2nd Embodiment. The figure which shows the example of a display by the bar graph of the state which shifted similarly (A) yawing direction, and (B) the state which canceled the shift | offset | difference

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

  In the first embodiment of the present invention, as shown in FIG. 5, apart from the position detection tracks 1 and 2 and the detection sensors 21 and 22, a lateral displacement amount is provided at one end (right end in the figure) of the detector 20. Is provided with a deviation amount detection sensor 31.

  The displacement amount detection sensor 31 detects the presence or absence of the scale tracks 11 and 12 using a line sensor such as a CMOS image sensor, for example, and a position detection track as illustrated in FIG. 5B. The positions of the first and second detection sensors 21 and 22 and the lateral positions of the scale tracks 11 and 12 are collated to determine whether the positional relationship between the scale 10 and the detector 20 is correct. In the case of FIG. 5, the peak of track 1 can be detected, but the peak of track 2 cannot be detected.

  The collation result between the position of the detection sensor and the scale track is output to a display unit such as a display LED or a personal computer. For example, as shown in FIG. 6A, (1) the peaks of tracks 1 and 2 can be completely taken. In the case of OK, (2) when the detector 20 is shifted upward as shown in FIG. 5 and the peak of the lower track 2 cannot be taken and the detector 20 should be moved downward, (3) conversely, the detector 20 is If the peak of the upper track 1 is not taken out and the detector 20 is to be moved upward, it is visually determined whether the positional relationship between the detection sensor and the scale track is correct. Since the displacement direction (and hence the movement direction of the detector) is also known, the adjustment can be easily performed.

  Further, as shown in FIG. 6B, if the bar graph is displayed, the amount of deviation can be grasped, and the mounting adjustment is further facilitated.

  According to the first embodiment, a lateral shift can be detected.

  Next, a second embodiment of the present invention will be described in which one shift amount detection sensor is added so that a shift in the yawing direction can also be detected.

  In the present embodiment, as shown in FIG. 7, displacement amount detection sensors 31 and 32 are provided at both ends of the detector 20 in the measurement direction.

  A configuration example of the detection circuit in the present embodiment is shown in FIG. In the figure, reference numeral 40 denotes a processing circuit for processing the outputs of the track 1 detection sensor 21 and the track 2 detection sensor 22 to obtain a displacement signal, and reference numeral 42 denotes an output of the displacement amount detection sensors 31 and 32 to detect the displacement. The microcomputer 44 for calculating the displacement at the positions of the amount detection sensor 31 and the displacement amount detection sensor 32, respectively, includes a personal computer 46, a display LED, and a display unit provided with a bar graph 48 displayed on the monitor of the personal computer 46, for example. It is.

  A display example of the bar graph is shown in FIG. FIG. 9A shows a state shifted in the yawing direction, and FIG. 9B shows a correct state adjusted in the yawing direction.

  In this way, according to the present embodiment, it is possible to easily confirm that a deviation in the yawing direction has occurred when the position of the scale track is different between the sensor outputs of the deviation amount detection sensors 31 and 32.

  In the above-described embodiment, the present invention is applied to an absolute linear encoder. However, the scope of application of the present invention is not limited to this, and the present invention is also applied to an incremental linear encoder, an arc encoder, and a rotary encoder. The same applies. The number of tracks is not limited to two, and may be one or three or more.

DESCRIPTION OF SYMBOLS 10 ... Scale 11, 12 ... Scale track 20 ... Detector 21, 22 ... Track detection sensor 31, 32 ... Deviation amount detection sensor

Claims (5)

In a separate encoder that has a scale in which a plurality of tracks extending in the measurement direction are arranged in parallel, the scale and the detector are separated, and needs to be aligned when attached to a measurement target.
The detector, set the shift amount detection sensor for detecting the lateral deviation perpendicular to the measurement direction by detecting a plurality of tracks,
A separate type encoder capable of displaying a lateral displacement between a scale and a detector.   The separate encoder according to claim 1, wherein the deviation amount detection sensors are provided at both ends in the measurement direction of the detector.   The separate encoder according to claim 1, wherein the shift amount detection sensor is a line sensor. Wherein the encoder is separate type encoder according to any one of claims 1 to 3, characterized in that the A blanking Seo absolute encoders. When mounting the separate encoder according to any one of claims 1 to 4,
A method for mounting a separate encoder, wherein the scale and the detector are aligned so that the lateral displacement between the scale and the detector detected and displayed by the displacement detection sensor is eliminated.

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