Abstract: A self-diagnosing system for an encoder. The system includes an encoder circuit for outputting information detected by an encoder; a data preparing section provided in the encoder circuit and preparing data representing a state of an abnormal-state judgment factor in connection with at least one of the encoder and an electric motor combined with the encoder; a signal generating section provided in the encoder circuit and generating an abnormal-state signal when the data prepared in the data preparing section represents an abnormal state of the abnormal-state judgment factor; and a storage section provided in the encoder circuit and storing the data representing a state of the abnormal-state judgment factor when the signal generating section generates the abnormal-state signal. The storage section may store the data prepared in the data preparing section at a desired timing not later than the instant the signal generating section generates the abnormal-state signal.

Abstract: An optical encoder includes a moving scale (1), a light source (2) which is always kept lighted, a fixed slit (3) and a light receiving array (4) having a plurality of light receiving units (41, 42). The light from the light source (2) is radiated toward the moving scale (1), thereby to generate signal light for a plurality of channels. The signal light for each channel passes through the opening (31; 32) of the fixed slit (3). The light passed through the opening (31) enters the light receiving unit (41), while the light passed through the opening (32) enters the light receiving unit (42). A plate-shaped light shield member (5) is interposed between the fixed slit (3) and the light receiving array (4) to optically separate the light passed through the opening (31) toward the light receiving unit (42) from the light passed through the opening (32) toward the light receiving unit (42) and thereby to prevent crosstalk between the channels.

Abstract: An encoder that can detect the presence of noise occurring within the encoder. The encoder is constructed by incorporating within the same apparatus: a movement detecting unit for detecting the movement of a moving body; a signal processing circuit for processing a movement detection signal supplied from the movement detecting unit, and thereby producing an encoder signal representing the position and/or the amount of displacement of the moving body; and a noise detecting unit for detecting noise superimposed on the movement detection signal. According to this encoder, a noise voltage generated within the encoder via a stray capacitance is detected within the encoder and is output as noise data, so that the noise level can be detected without requiring the use of an external measuring device. Further, by outputting encoder data and noise data occurring at the same instant in time, the reliability of the encoder data can be judged based on the condition of the noise level.

Abstract: A rotary disc for use in a rotary encoder includes a signal generation section having a pattern formed thereon to generate a signal indicative of a rotational angle/phase. The signal generation section has a peripheral surface, which is provided with a linear portion usable as an indicator indicative of the rotational angle/phase represented by the signal generation pattern on the signal generation section. A robot hand is employed to hold the linear portion and attach it through an attachment portion of the rotary disc to a rotor shaft of a motor.

Abstract: An optical rotary encoder using a fluid bearing, which is space-saving, holds down the costs for high-precision processing of components, and has excellent maintainability. A rotary disk is fixed to a disk holder and accommodated in a cylindrical case together with a fluid bearing mechanism and an optical detection unit. The optical detection unit and the fluid bearing mechanism compose a static system with the case, which maintains a stationary state even if a rotary shaft is rotated, and are mounted on static system mounting portions with the case. The disk holder and the rotary disk are fitted on the rotary shaft. Compressed air is sprayed onto both sides of the rotary disk through a compressed air flow path and a compressed air nozzle, to thereby restrict the displacement of the disk, which is generated in the direction parallel to the rotary shaft.

Abstract: A rotary encoder easily position-adjusted in relation to a rotary shaft and is reduced in accuracy deterioration attributable to rotational unstableness and the like which is caused after attachment to the rotary shaft. The encoder is a device attached to the rotary shaft to outputting signals with the rotation of the shaft. The encoder includes a rotary disk, a detector for detecting rotational position of the rotary disk, a disk holder for fixedly attaching the rotary disk to the rotary shaft, and a housing for fixing the detector such that the detector is opposed to the rotary disk. The encoder comprises a retainer attachable to and detachable from the disk holder and the housing for retaining positional relation between the disk holder and the housing.

Abstract: A rotary encoder and a kit thereof. The kit for a rotary encoder includes a plurality of signal generating members for generating mutually different signals, any selected one of the signal generating members being able to be attached in an exchangeable manner to a rotary body; and a signal sensing unit arranged in close proximity to one selected signal generating member attached to the rotary body, for sensing a signal generated due to a rotation of the signal generating member. The signal generating members are respectively formed in such a manner that the numbers of signal-cycles and the signal-intervals in signals generated during a unit rotation of respective signal generating members are different from each other, while the products of the numbers of signal-cycles multiplied by the signal-intervals in the signals are generally identical to each other.

Abstract: An assembly of electric motor with encoder, including an electric motor having a motor housing, and an encoder for detecting the rotation angle of the output shaft of the electric motor. The encoder includes a frame member attached to the motor housing in a conductive manner, a circuit board supported on the frame member and a detection circuit provided in the circuit board. The assembly of electric motor with encoder further includes an output signal cable connected to the circuit board of the encoder and including a signal wire and a shield member, and a grounding mechanism electrically connecting the shield member of the output signal cable to the motor housing for grounding purposes. The grounding mechanism includes a conductor patterned on the circuit board, a first connecting structure mutually connecting the conductor to the shield member, and a second connecting structure mutually connecting the conductor to the frame member.

Abstract: A coupling for a motor including a first coupling member, a second coupling member and an intermediate member disposed between the first and second coupling members and slidably engaged with the first and second coupling members. The intermediate member includes a slider main body and an embedded member embedded in the slider main body, whereby the overall rigidity of the intermediate member is increased.

Abstract: A rotary disc for use in a rotary encoder includes a signal generation section having a pattern formed thereon to generate a signal indicative of a rotational angle/phase. The signal generation section has a peripheral surface, which is provided with a linear portion usable as an indicator indicative of the rotational angle/phase represented by the signal generation pattern on the signal generation section. A robot hand is employed to hold the linear portion and attach it through an attachment portion of the rotary disc to a rotor shaft of a motor.

Abstract: An optical encoder with a high utilization efficiency of light and easy to manufacture. The optical encoder comprises a conversion device formed in such a manner that lens elements are arranged periodically with a reference pitch IP for converting a beam L emitted from a light source into a plurality of shifting beams MF. The beam L is contracted to a half of the reference pitch IP by the conversion device and goes out as a parallel beam, to impinge on a light receiving section. On a board of the light receiving section there are arranged light receiving elements with a pitch of IP/2. When an object connected to the conversion device is rotated or translated, the position of each lens element changes synchronously and the shifting beam MF scans an arrangement of the light receiving elements. As a result, a ratio of a light amount reaching the light receiving element changes periodically. The resultant electrical signal is processed by a well-known processing circuit.

Abstract: After cyclic original signals generated from a sensing element of an encoder are converted into digital signals, positions P(0) to P(n) in one period are obtained for each given period by means of a digital interpolator. If position data obtained immediately after a zero cross point is detected are P(0) and P(n) and if speed is fixed, an object should move on a straight line from a position P(0) to a position P(n). An actual detected position data P(m) is deviated from this straight line by D(m). This detection error D(m) and the detected position data P(m) are combined and stored in advance as reference data, and correction is carried out using the reference data every time position data is detected by the digital interpolator.

Abstract: An optical encoder with a high utilization efficiency of light and easy to manufacture. The optical encoder comprises a conversion device (7) formed in such a manner that lens elements (71, 72) are arranged periodically with a reference pitch IP for converting a beam L emitted from a light source into a plurality of shifting beams MF. The beam L is contracted to a half of the reference pitch IP by the conversion device (7) and goes out as a parallel beam, to impinge on a light receiving section (4). On a board (41) of the light receiving section (4), there are arranged light receiving elements (42) with a pitch of IP/2. When an object connected to the conversion device (7) is rotated or translated, the position of each lens element (71, 72) changes synchronously and the shifting beam MF scans an arrangement of the light receiving elements (42). As a result, a ratio of a light amount reaching the light receiving element (42) changes periodically.

Abstract: An industrial machine in which vibration exerted on a position detector provided for an axis of the machine is detected and countermeasures against the vibration can be swiftly taken. A ball screw is driven by a servo motor MZ supplied with power from a servo amplifier via a power line so that a cutting unit is advanced and retracted. A spindle motor MS above the cutting unit rotates a cutting tool via a spindle shaft and a workpiece W on an XY table is machined. An acceleration detection element is built in a position detector attached to a motor shaft of the servo motor MZ. An angle detection signal for servo control and a vibration level signal outputted by the acceleration detection element are converted into serial signals and are transmitted to a controller (axis control circuit of Z-axis) via the common signal line. The controller takes measures of changing the machining condition (for example, change of spindle rotational speed) and stopping the machine in accordance with a rank of the vibration.

Abstract: It is assumed that an element to be detected 2a in a position sensor is mounted on a rotary shaft with the center O′ of the element to be detected eccentric from a center of rotation O by a distance d. When the rotary shaft is rotated at a fixed speed, the positions at angles 0° and 180° are accurately detected by a sensor 2b, while the positions at angles 90° and 270°, the sensor detects the positions P1′ and P3′, instead of P1 and P3 which are originally to be detected, resulting in undulation of detected positions as shown in FIG. 3(b). The peak value of the unduration and an angle of rotation at which the peak value is found are determined.

Abstract: An optical rotary encoder simple in construction and capable of easily securing an aligned state of a code plate with a rotating shaft A disk DS and an attachment portion DM of a code plate (6) are formed of an integrated plastic molded product, so that the assembly work for the code plate (6) itself is unnecessary. A lens group is formed in a predetermined region of the disk DS. When a fitting portion RE of a shaft member (20) is press fitted into an insertion hole DE, alignment holding portions (J1 to J3) are deformed plastically to thereby achieve the alignment. The attachment portion DM and the shaft member (20) are fixed to each other by engaging a fixing bolt BL with threaded holes DH and RH. A plurality of alignment holding portions (K1 to K3) may be provided at the outer peripheral surface of the attachment portion DM. In this case, the alignment is achieved by press fitting the attachment portion DM into a fitted portion RF and plastically deforming the alignment holding portions (K1 to K3).

Abstract: A movable code plate for an optical encoder is given a light path changing function by forming a series of indentations in one or more portions of one surface of the plate. Since these indentation are sufficiently shallow with respect to the thickness of the movable code plate, sufficient strength of the movable plate is maintained. These indentations can be formed on the surface of the movable code plate without a high accuracy. These indentations may be V-shaped grooves or matted surfaces.

Abstract: A mobile code plate manufactured, such as by plastic injection molding, encodes input light by the light path alteration function of a first optical bending portion. This is converted into a first output optical flux by perpendicular incidence and optical transmission at the position of input of a first input optical flux and is then input to a first photodetector element. Since the first optical bending portion arrives at the input position of a second input optical flux, a bent second output optical flux is generated and is likewise input to the first photodetector element. As the mobile code plate rotates, a second optical bending portion arrives at the input position of the first input optical flux. When the first optical bending portion leaves the input position of the second input optical flux, third and fourth output optical fluxes are input to a second photodetector element with the result that an inverted signal is obtained.

Abstract: An offset correcting circuit for an encoder capable of detecting a correct offset value even when a sampling period is long as in the case of a low-speed A/D converter and restraining the influence of noise. The offset correcting circuit for an encoder adapted to output an angle signal based on digital signals obtained by performing A/D conversions of two signals having phases different by about 90 degrees in accordance with the same timing includes an offset detecting circuit for obtaining an offset value of one of the two signals, using an A/D converted value of that one signal which is obtained when an A/D converted value of the other of the two signals is zero or close to zero, and a compensating circuit for compensating an offset of that one signal using the offset value detected by the offset detecting circuit.

Abstract: An encoder interpolation circuit for obtaining interpolation data within one wave from two sine-wave encoder signals of different phases comprises interpolative computation means (2) for receiving two sine-wave encoder signals received and carrying out to interpolative computation within one wave, signal deviation detecting means (3) for detecting a deviation of the two sine-wave encoder signals, correction data forming means (4) for outputting correction data corresponding to the detected deviation and the output of the interpolative computation means, and corrective computation means (5) for obtaining the corrected interpolation data by carrying out corrective computation for the output of the interpolative computation means with the correction data and obtaining corrected interpolation data.