JP4872340B2 - Method and apparatus for assembling rotary slit plate of rotary encoder - Google Patents

Description

  The present invention relates to a rotating slit plate assembling method and apparatus used when assembling a rotary encoder.

  In the process of assembling the rotary slit plate of the rotary encoder, it is necessary to accurately position the rotary slit plate so as not to be eccentric with respect to the rotation center of the rotary shaft, thereby minimizing vibration during rotation. Conventionally, two methods are generally known as methods for that purpose.

  The first method is to perform image measurement while keeping both the rotating shaft and the rotating slit plate stationary, and position the geometric centers obtained from the respective shapes to coincide with each other. The second method is, for example, As described in Patent Document 1, a rotary slit plate is temporarily placed on a rotary shaft, and the position is adjusted so that rotational shake is minimized while actually rotating.

In more detail, the position adjustment of the rotary slit plate in the second method is more specifically performed by rotating a temporarily assembled rotary encoder on which the rotary slit plate is temporarily placed by a pulse motor (rotation step) and continuously imaging with a fixed CCD camera. While tracking the position of the perfect circle pattern of the rotating slit plate that is rotating on the image, measure the deflection and displacement (shake measurement step), and obtain the maximum displacement position of the deflection of the rotating slit plate (maximum displacement position) Detection step), this is set as a position to stop the push jig installation position (stop position determination step), and the rotary slit plate is stopped so that the maximum displacement position comes to the push jig installation position (rotation slit plate stop step) Then, press the stopped rotating slit plate in the 1/2 diameter direction of the swinging width with a pressing jig to reduce the swinging (rotating slit plate pushing step) Again, the amplitude is measured, if not within specification (determination step), and is intended to repeat the series of operations.
JP 2000-028397 A

  In the first method, there are cases where the center of the obtained rotation axis does not coincide with the actual rotation center due to the accuracy of image measurement, the accuracy of the shape of the rotation shaft, the swing of the shaft itself, and the like. In such a case, there is a problem that even if the measurement / positioning accuracy is improved, the deflection of the rotating slit plate is not improved. On the other hand, in the second method, in order to adjust the position so that the rotational slit plate is actually rotated in a temporarily assembled state and the vibration is reduced, the rotational vibration can be made smaller than that in the first method. it can. However, in the second method, in order to detect the maximum displacement position of the shake, the position at which the shake becomes the maximum displacement is recorded by the position measurement on the image, and it is determined when the position reaches again. Therefore, there is a problem that the accuracy deteriorates due to the following.

  i) In the vicinity of the maximum displacement of the shake, the position change on the image is small, and the resolution for determining the arrival of the maximum displacement is poor, so the error becomes large.

  ii) The maximum displacement value of the previous round may not be reached slightly, and it is necessary to give an appropriate width to the determination in advance, thereby increasing variations and errors.

  iii) A phenomenon in which the fluctuation of the fluctuation fluctuates in the vicinity of the maximum displacement occurs, and when the above i) and ii) are combined, there is a case where the peak does not really coincide with the required maximum deviation of displacement, which is a false detection.

  Further, in the second method, in order to suppress the shake within the standard of several μm, it is necessary to repeat the shake measurement to adjustment, and there is a problem that the total assembly time tends to be long.

  An object of the present invention is to provide a rotary slit plate assembling method and apparatus for a rotary encoder, which can eliminate errors and false detections that have been problems in the conventional method, and can improve the assembling accuracy.

The rotary slit plate assembly method of the rotary encoder according to the first aspect of the invention is such that when the rotary slit plate is assembled so as not to be eccentric to the rotary shaft, the rotary assembled rotary encoder on which the rotary slit plate is temporarily placed is rotated to rotate the rotary slit plate. Find the maximum displacement position of the runout, stop the rotary slit plate so that this maximum displacement position is at the push jig installation position, and press the stopped rotary slit plate in the radial direction with the push jig to reduce the runout. In the rotary slit plate assembling method of the rotary encoder in which the rotational runout is less than the standard value by rotating the temporary assembly rotary encoder by at least one turn and measuring the runout and displacement, setting a small difference value Ri by which determine the maximum displacement of the deflection during rotation as the threshold value, the provisional-assembly rotor Rotating the encoder one more revolution, measuring the time ΔT that exceeds the threshold during this time, and further rotating the temporarily assembled rotary encoder to set the position where the time ΔT / 2 has passed after exceeding the threshold to the maximum displacement position And a step including:

  The rotary encoder, for example, passed through a rotating shaft supported by a housing via a pair of rolling bearings, a rotating slit plate fixed to the rotating shaft, a fixed slit plate fixed to the housing, and the rotating slit plate. A light receiving element that receives light from the light emitting element and converts it into an electric signal, and a substrate provided with a circuit that processes the electric signal of the light receiving element are provided.

  The rotating slit plate is, for example, a disc made of a transparent material such as glass provided with light shielding portions or transmission portions at a predetermined pitch. The material of the rotating slit plate and the means for forming the slit can be variously changed.

  The pushing amount of the rotary slit plate by the pushing jig is changed so as to be 1/2 (just 1/2 or almost 1/2) of the swing width for each adjustment.

  Temporary assembly can be performed using, for example, an ultraviolet curable adhesive as means for fixing the rotating plate to the rotating shaft, and using the adhesive strength of the adhesive. The method of performing temporary assembly is not limited to this, and may be performed mechanically without using an adhesive, for example.

  The rotary slit plate assembly method in the second conventional method described above includes a rotation step, a shake measurement step, a maximum displacement position detection step, a stop position determination step, a rotary slit plate stop step, a rotary slit plate push-in step, and a determination step. In contrast, the rotating slit plate assembling method according to the present invention has the same rotation step, deflection measurement step, rotating slit plate stop step, rotating slit plate pushing step and determination step as the conventional one, and the conventional maximum displacement. Instead of a position detection step and a stop position determination step (hereinafter, a combination of the two steps may be referred to as a “stop position detection step”), a threshold setting step, a threshold crossing time measurement step, and a stop position Decision step (a combination of the three steps And has a position detection step ".) The has.

  The position adjustment of the rotary slit plate is performed by a shake measurement step, a stop position determination step, a rotary slit plate push-in step, etc. Of these steps, the accuracy improvement in the measurement step and the rotary slit plate push-in step is It can be realized relatively easily by increasing the accuracy. According to the present invention, it is possible to improve the accuracy in the stop position detection step, which is difficult to achieve by improving the accuracy of image measurement. That is, in the present invention, in order to solve the problems i), ii) and iii) of the prior art shown in the problem to be solved by the invention, the maximum displacement position is not directly detected (the conventional maximum). By eliminating the displacement position detection step) and utilizing the fact that the shake displacement becomes a peak-symmetrical sinusoidal repetitive waveform, detection of the maximum shake displacement is performed not by determination by the shake position but by processing by time. Specifically, on the repetitive waveform of the deflection displacement, if the position where the displacement is slightly smaller than the maximum displacement and the displacement transitions relatively stably is set as a threshold, and the time ΔT displaced in a range equal to or more than the threshold in one cycle is measured, Utilizing the fact that the maximum runout position should have been reached when ΔT / 2 has elapsed since the time when the range was reached in the next lap, thereby causing problems of conventional i), ii) and iii) Can be avoided, accuracy can be improved, and the number of adjustment iterations can be reduced.

  According to the second conventional method, the rotational slit plate is rotated once (at least one rotation) to determine the position and amplitude of the maximum deflection displacement on the image, and the maximum displacement position is detected in the next round. Therefore, in principle, the time from the start of shake measurement until the detection of the maximum displacement position is equivalent to a little over 1 turn to a little under 2 turns (differing in the initial eccentric phase) (when the safety factor is not expected).

  In the method of assembling the rotary slit plate of the rotary encoder according to the first aspect of the invention, in order to determine the effective threshold, the rotary slit plate is rotated once (at least once) to determine the maximum displacement and the swing width. This is the same as the conventional method, but after this time, the time ΔT that exceeds the threshold is measured (up to this point, it needs to be slightly more than one turn to less than two turns), and the rotation is stopped using ΔT / 2 in the next turn. As a result, the time from the start of shake measurement to the detection of the maximum displacement position is in principle a little more than 2 to less than 3 turns (which differs depending on the initial eccentricity phase). ) It will be considerable.

  Therefore, the rotary slit plate assembling method of the rotary encoder according to the first aspect of the invention can reduce the number of repetitions of adjustment, but the time required for detecting the position reaching the maximum displacement (stop position detecting step) There is a problem that the time is longer and the overall time reduction (throughput improvement) is not sufficient.

The method of assembling the rotary slit plate of the rotary encoder according to the second aspect of the invention can solve this problem, and the rotary slit plate is temporarily placed when the rotary slit plate is assembled to the rotary shaft so as not to be eccentric. Rotate the temporarily assembled rotary encoder to obtain the maximum displacement position of the deflection of the rotary slit plate, stop the rotary slit plate so that this maximum displacement position comes to the push jig installation position, and press the stopped rotary slit plate In the rotary slit plate assembly method of the rotary encoder that reduces the runout by pushing it in the 1/2 radial direction of the runout and repeats this, the rotary encoder is rotated at least one turn. The relationship between the step of measuring runout and displacement and the time of rotation for at least one round and the runout displacement is A step of ring, obtains the maximum displacement of the deflection from the data obtained by the sampling, and sets small again value Ri Kitareyo as a threshold, a step of computing a time ΔT exceeds the threshold value, further rotation of the provisional-assembly rotary encoder And the step of setting the position where the time ΔT / 2 has passed after the threshold value is exceeded as the maximum displacement position.

  The rotary slit plate assembly method of the rotary encoder according to the invention of claim 2 is different from the first invention in that the transition is sampled during the measurement of the deflection displacement. The time ΔT exceeding the threshold can be calculated from the immediately preceding waveform. Accordingly, it is possible to eliminate the rotation for one round for obtaining the threshold crossing time required in the first invention. Thereafter, as in the first aspect of the invention, the temporary assembly rotary encoder is further rotated, and the position where the time ΔT / 2 has passed after the threshold value is exceeded is set as the maximum displacement position, thereby obtaining an accuracy improvement effect and adjustment. The number of repetitions can be reduced.

A rotary slit plate assembling apparatus for a rotary encoder according to a third aspect of the invention includes a support member for supporting the temporarily assembled rotary encoder in which the rotary slit plate is temporarily placed on the rotary shaft, a rotating means for rotating the rotary shaft, and a rotary slit. Rotating slit plate pushing jig for pushing the plate in the radial direction, pushing jig moving means for moving the rotating slit plate pushing jig, an imaging device for imaging a certain range of the rotating slit plate, rotating means and pushing treatment A control means for controlling the tool moving means and an image obtained by the image pickup device are processed to determine the shake displacement of the rotary slit plate, and necessary signals are output to the image pickup device and the control means as appropriate according to the shake displacement data. threshold with the rotary slit plate assembly device of a rotary encoder and a CPU, and a maximum displacement of the determined threshold so by Ri small again value of runout A threshold beyond time detecting means obtaining a time above [Delta] T, and is characterized in that it comprises a stop position determining means for the additional time [Delta] T / 2 elapses position after exceeding the threshold value and the stop position.

  A rotary slit plate assembling device for a rotary encoder according to a fourth aspect of the present invention is the rotary slit plate assembling device for a rotary encoder according to the third aspect of the invention, wherein the time when the temporarily assembled rotary encoder is rotated at least one turn is Sampling means for sampling the relationship with the shake displacement is further provided, and a time ΔT exceeding the threshold is calculated from the immediately preceding waveform after the threshold is determined.

  The threshold crossing time detection means, stop position determination means, and sampling means are all incorporated in a CPU (for example, a personal computer) as part of a program that automatically performs a series of operations.

  According to the rotary slit plate assembly apparatus of the rotary encoder of claim 3, the method of claim 1 can be easily performed, and according to the rotary slit plate assembly apparatus of the rotary encoder of claim 4, the method of claim 2. Can be easily performed.

  According to the method of assembling the rotary slit plate of the rotary encoder of the first and second aspects of the invention, the rotary slit plate is temporarily placed on the rotary shaft, and the position is adjusted so that the rotational shake is minimized while actually rotating. Since it is based on the method, it is highly reliable, and the errors and false detections that are problems in this method can be eliminated, so the number of adjustment iterations can be reduced, and productivity can be reduced. Can be improved. Moreover, since no special device or complicated algorithm is required to obtain this effect, the productivity improvement effect can be obtained at low cost.

  According to the first aspect, the number of repetitions of shake measurement to adjustment can be reduced by improving accuracy, so that the assembly time can be shortened, but the time required for one shake measurement to adjustment is set to a threshold value. Since it is necessary to obtain a time exceeding the time, it increases compared to the conventional method, and this reduces the amount of decrease in the assembly time. The time required for measurement to adjustment can be made the same as that of the conventional method, and the amount of assembly time can be reduced, and thus the productivity can be greatly improved.

  According to the rotary slit plate assembling apparatus of the rotary encoder of the third and fourth aspects of the invention, the rotary slit plate is temporarily placed on the rotary shaft, and the position is adjusted so that the rotational shake is minimized while actually rotating. Since it is based on the method, it is highly reliable, and the errors and false detections that are problems in this method can be eliminated, so the number of adjustment iterations can be reduced, and productivity can be reduced. Can be improved. Moreover, since no special device or complicated algorithm is required to obtain this effect, the productivity improvement effect can be obtained at low cost.

  According to the third aspect of the present invention, the number of repetitions of shake measurement to adjustment can be reduced by improving accuracy, so that the assembly time can be shortened, but the time required for one shake measurement to adjustment is set to a threshold value. Since it is necessary to obtain a time exceeding the time, it increases compared to the conventional method, and this reduces the amount of decrease in assembly time. The time required for measurement to adjustment can be made the same as that of the conventional method, and the amount of assembly time can be reduced, and thus the productivity can be greatly improved.

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

  FIG. 1 shows a rotary slit plate assembling apparatus for a rotary encoder according to the present invention.

  In FIG. 1, a rotary slit plate (4) is formed on a spindle assembly (3) formed by supporting a hollow rotary shaft (6) via a pair of rolling bearings (7) on a housing (5) with a slit (5a). ) Is a temporarily assembled rotary encoder (2), and the rotary encoder rotary slit plate assembly device (1) includes a pallet (support member) (11) that supports the temporarily assembled rotary encoder (2), A pulse motor (rotating means) (12) for rotating the rotating shaft (6) of the temporarily assembled rotary encoder (2), a motor driver (13) for driving the pulse motor (12), and a rotating slit plate (4) Rotating slit plate pushing jig (14) for pushing in the radial direction, pushing jig horizontal moving device (pushing jig moving means) (15) for moving the rotating slit plate pushing jig (14), and pushing jig A push jig driver (16) that drives the horizontal movement device (15) and a pallet (11) A CCD camera (imaging device) (17) that images the fixed range (4a) of the rotating slit plate (4) from the window (11a) to the rotating slit plate (4), a motor driver (13), and a pushing jig The driver control means (18) for controlling the driver (16) and the image obtained by the CCD camera (17) are processed to create the deflection displacement of the rotating slit plate (4), and according to the deflection displacement data A personal computer (CPU) (19) that appropriately outputs necessary signals to the CCD camera (17) and the driver control means (18) is provided.

  In the above, the configuration of the hardware part of the rotary slit plate assembling apparatus (1) of the rotary encoder is the same as that of the conventional one, and the detailed description thereof is omitted.

  The driver control means (18) has a PLC (programmable logic control) (18a) and a pulse unit (18b). By supplying signals in a predetermined order, the motor driver (13) and the push jig driver (16) is controlled to work together.

  In the personal computer (19), a program (image processing means) that calculates the displacement of the shake by processing the image obtained by the CCD camera (17), and from the displacement of the shake obtained by the image processing, the rotation slit plate (4) A program for obtaining a position to be stopped (stop position detecting means) is provided.

  On the rotating slit plate (4), a perfect circle pattern (4b) for shake measurement is set, and the difference between this and the center of the swing width assuming the reference perfect circle (S) is obtained as the deflection displacement. . The absolute position of the reference perfect circle (S) depends on the work setting accuracy, and the final reference perfect circle (S) is determined after one cycle. On the display device of the personal computer (19), the image obtained by the CCD camera (17), that is, the displacement d (t) of the current shake and the maximum displacement D when rotated by one round are displayed.

  The deflection curve obtained by image processing the data from the CCD camera (17) is such that the sine wave is partially uneven, and when partially enlarged, for example, FIG. The shape is as shown in FIG. Conventionally, in FIG. 2 (b), the position where the deflection becomes the maximum displacement is the maximum displacement reaching point. Therefore, there is a problem that errors and false detections increase as in the above i) to iii). On the other hand, in the method of the present invention, as shown in FIG. 2A, when ΔT / 2 has elapsed when the time when the deflection displacement exceeds the threshold is ΔT, the maximum displacement arrival point is set. That is, since the conventional “maximum displacement position” is the position that is the maximum displacement itself (microscopic maximum displacement position), the error is large, whereas in the present invention, the “maximum displacement position”. Is the peak position (macro maximum displacement position) when the vibration is approximated by a sine wave, and this improves the accuracy.

  In the first embodiment of the method of assembling the rotary slit plate of the rotary encoder according to the present invention, the stop position detecting step is a step of obtaining the maximum displacement of the shake during rotation for one round and setting a value slightly smaller than this as a threshold value ( A threshold calculation step), a step of rotating the temporarily assembled rotary encoder (2) by one more turn, and measuring a time ΔT exceeding the threshold during this time (threshold exceeding time calculating step), and a temporarily assembled rotary encoder (2) Further, the method further includes a step (stop position determination step) in which a position where the time ΔT / 2 has passed after the rotation further exceeds the threshold is set as a stop position (maximum displacement equivalent position).

  That is, referring to FIG. 3, first, the temporarily assembled rotary encoder (2) is rotated by one turn, and the maximum displacement of the shake is obtained during the rotation of one turn, and a value slightly smaller than this is set as a threshold value (this At the stage, ΔT is not determined.) Next, the temporarily assembled rotary encoder (2) is further rotated by one round, and the time ΔT exceeding the threshold is measured during this time. Then, the temporarily assembled rotary encoder (2) is further rotated, and the position where the time ΔT / 2 has elapsed after exceeding the threshold value is set as the maximum displacement position and stopped at the pushing jig installation position. Thereafter, by pushing the pushing jig (14) in the ½ diameter direction of the maximum displacement of the shake, one shake adjustment operation is completed. Thereafter, returning to the first step, if the maximum displacement of the shake is not less than the standard value, the next shake adjustment operation is performed. In the first step, when the maximum displacement is equal to or less than the standard value, it is determined that the adjustment operation is completed, and the rotary slit plate (4) is fixed to the rotary shaft (6). Thus, a series of shake adjustment operations are automatically performed, and the assembly operation of the rotary slit plate (4) is completed.

  In the second embodiment of the rotary slit plate assembling method of the rotary encoder of the present invention, the stop position calculating step includes a step (sampling step) of sampling the relationship between the time during rotation for one round and the deflection displacement. The maximum displacement of the shake is obtained from the data obtained by sampling, a value slightly smaller than this is set as a threshold value, a time ΔT exceeding the threshold value is calculated (threshold value exceeding time calculation step), and a temporary assembly rotary encoder ( 2) is further rotated, and a step (stop position determination step) in which a position where time ΔT / 2 has elapsed after exceeding the threshold is set as a stop position (maximum displacement equivalent position) is included.

  That is, referring to FIG. 4, first, the temporarily assembled rotary encoder (2) is rotated by one turn, the maximum displacement of the shake is obtained during the rotation of one turn, and a value slightly smaller than this is set as a threshold value. Here, the difference from the first embodiment is that the transition is sampled during the measurement of the deflection displacement, whereby the time ΔT exceeding the threshold is calculated from the immediately preceding waveform after the threshold is determined. be able to. Therefore, it is possible to eliminate the rotation for one round for obtaining the threshold crossing time required in the first embodiment. Thereafter, the same procedure as in the first embodiment may be performed, and the temporarily assembled rotary encoder is further rotated, and the position where time ΔT / 2 has passed after the threshold value is exceeded is set as the maximum displacement position and stopped at the pressing jig installation position. After that, by pushing the pushing jig (14) in the ½ diameter direction of the maximum displacement of the deflection, one shake adjustment operation is completed. Then, when the shake adjustment operation is repeated and the maximum displacement becomes equal to or less than the standard value, it is determined that the adjustment operation is completed, and the rotating slit plate (4) is fixed to the rotating shaft (6). Thus, a series of shake adjustment operations are automatically performed, and the assembly operation of the rotary slit plate (4) is completed.

FIG. 1 is a block diagram showing a rotary slit plate assembling apparatus for a rotary encoder according to the present invention. FIG. 2 is a diagram for explaining the difference between the rotary slit plate assembly method of the rotary encoder according to the present invention and the conventional method. FIG. 3 is a diagram showing one shake correction time in the rotary slit plate assembling method of the rotary encoder according to the first aspect of the present invention. FIG. 4 is a diagram showing one shake correction time in the method of assembling the rotary slit plate of the rotary encoder according to the second aspect of the present invention.

Explanation of symbols

(2) Temporary assembly rotary encoder
(4) Rotating slit plate
(6) Rotating shaft
(11) Pallet (support member)
(12) Pulse motor (rotating means)
(14) Rotating slit plate pushing jig
(15) Push jig horizontal moving device (push jig moving means)
(17) CCD camera (imaging device)
(18) Driver control means (control means)
(19) PC (CPU)

Claims (4)

When assembling the rotary slit plate so as not to be eccentric to the rotary shaft, the temporary assembly rotary encoder on which the rotary slit plate is temporarily placed is rotated to obtain the maximum displacement position of the deflection of the rotary slit plate, and this maximum displacement position is the pressing jig. Stop the rotary slit plate so that it is at the installation position, push the stopped rotary slit plate in the radial direction with a pressing jig to reduce the shake, and repeat this to rotate the rotary slit of the rotary encoder to make the rotational shake less than the standard value In the plate assembly method,
A step of measuring the vibration and the displacement by rotating at least one round of the provisional-assembly rotary encoder, and setting a small difference value Ri by which determine the maximum displacement of the vibration during rotation of the at least one round of the threshold, provisionally Rotating the combined rotary encoder one more turn, measuring the time ΔT exceeding the threshold during this period, and further rotating the provisional rotary encoder further to the position where the time ΔT / 2 has passed after the threshold is exceeded And a rotary slit plate assembling method for the rotary encoder. When assembling the rotary slit plate so as not to be eccentric to the rotary shaft, the temporary assembly rotary encoder on which the rotary slit plate is temporarily placed is rotated to obtain the maximum displacement position of the deflection of the rotary slit plate, and this maximum displacement position is the pressing jig. Stop the rotary slit plate so that it is at the installation position, push the stopped rotary slit plate in the radial direction with a pressing jig to reduce the shake, and repeat this to rotate the rotary slit of the rotary encoder to make the rotational shake less than the standard value In the plate assembly method,
From the step of measuring the shake and displacement by rotating the temporarily assembled rotary encoder by at least one turn, the step of sampling the relationship between the rotation time and the shake displacement of at least one turn, and the data obtained by sampling determine the maximum displacement of the deflection, and sets small again value Ri Kitareyo as a threshold, a step of computing the time [Delta] T above the threshold, further rotate the provisional-assembly rotary encoder, more time after exceeding a threshold value [Delta] T / 2 And a rotary slit plate assembling method for a rotary encoder, comprising the step of setting the elapsed position as a maximum displacement position. A support member that supports a temporarily assembled rotary encoder in which a rotary slit plate is temporarily placed on a rotary shaft, a rotating means that rotates the rotary shaft, a rotary slit plate pushing jig for pushing the rotary slit plate in a radial direction, and rotation A pressing jig moving means for moving the slit plate pressing jig, an imaging device for imaging a certain range of the rotating slit plate, a control means for controlling the rotating means and the pressing jig moving means, and an image obtained by the imaging apparatus In the rotary slit plate assembling apparatus of the rotary encoder provided with a CPU that calculates the deflection displacement of the rotary slit plate by processing and appropriately outputs signals necessary for the imaging device and the control means according to the data of the deflection displacement,
Stop for a threshold beyond time detecting means obtaining a time [Delta] T above the threshold, the more time [Delta] T / 2 elapses position after exceeding the threshold value and the stop position with a maximum displacement of the determined threshold so by Ri small again value of runout A rotary slit plate assembling apparatus for a rotary encoder, comprising: a position determining means.   A sampling means for sampling a relationship between a time when the temporarily assembled rotary encoder is rotated at least one turn and a deflection displacement is further provided, and a time ΔT exceeding the threshold is calculated from the immediately preceding waveform after the threshold is determined. 3 is a rotary slit plate assembling device of the rotary encoder of 3.

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