JP2010078410A - Method and apparatus for manufacturing magnetic type rotary encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for manufacturing a magnetic type rotary encoder, capable of easily lessening variations in a clearance dimension between a magnetic sensor and a magnetic pattern. <P>SOLUTION: In the method, a magnetic drum is held so as to face a magnetic sensor unit and to be separated from the magnetic sensor unit by a prescribed distance; then a planar sheet and a spacer having a projection on a flat plate are disposed, inside a space produced between the magnetic sensor unit and the magnetic drum above facing-holding step, and after above disposing step; the magnetic sensor unit is pressed against the magnetic drum perpendicularly to the spacer and the planer part of the sheet; and then the spacer and the sheet are removed therefrom, thereby easily lessening the variations in the clearance dimension in between the magnetic sensor and the magnetic pattern. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a magnetic rotary encoder including a magnetic sensor unit and a manufacturing apparatus used for manufacturing the magnetic rotary encoder.

  Generally, a magnetic rotary encoder includes a magnetic drum and a magnetic sensor. The magnetic drum is a drum fixed to a rotating shaft and magnetized with a magnetic pattern in the circumferential direction thereof, and the magnetic sensor is disposed at a certain angular position in the circumferential direction of the magnetic drum and close to the magnetic pattern. This is a magnetic sensor equipped with an electric circuit including a magnetic resistance (MR) element that outputs an electric signal corresponding to the magnetic field intensity. In such a magnetic rotary encoder, the rotational angle position of the rotary shaft can be known by detecting the strength signal of the magnetic field intensity emitted from the magnetic pattern with a magnetic sensor, converting it to an electrical signal, and analyzing it.

  It is necessary to arrange the magnetic pattern and the magnetic sensor while maintaining a certain design gap dimension determined from the shape of the magnetic pattern and the characteristics of the magnetoresistive element arranged in the magnetic sensor. When the magnetic sensor and the magnetic pattern are closer than the design gap size, the output of the magnetic sensor is saturated, and the magnetic sensor is not required not only from the closest magnetic pattern but also from the magnetic pattern located in the vicinity thereof. A strong magnetic field is detected, and the output waveform is distorted. As a result, the rotation angle detection accuracy decreases. On the other hand, when the magnetic sensor and the magnetic pattern are separated from each other than the design gap size, the magnetic field strength decreases in proportion to the square of the distance, so that the output of the magnetic sensor rapidly decreases and the rotation angle is detected. Accuracy will be reduced. For this reason, the magnetic sensor generally needs to be arranged with a positional accuracy of ± several tens of μm with respect to the magnetic pattern with reference to the design gap dimension.

  As a method of arranging the magnetic sensor with the design gap dimension with respect to the magnetic pattern, for example, as described in Patent Document 1, first, the magnetic sensor is arranged in the vicinity of the design gap dimension, and the output of the magnetic sensor is monitored. However, a method of finely adjusting the position of the magnetic sensor so that the output waveform is maximized and the waveform distortion is reduced, or a jig having a thickness corresponding to the design gap dimension is sandwiched between the magnetic sensor and the magnetic drum. In general, any one of the methods of positioning and fixing the magnetic sensor on the basis of the jig and then removing the jig is used.

  As another method, for example, Patent Document 2 discloses a structure in which a gap between the two is kept constant by bringing a magnetic sensor into close contact with a magnetic drum via a spacer.

  For example, Patent Document 3 discloses a magnetic encoder in which a magnetic sensor is placed in direct contact with a magnetic pattern.

  On the other hand, magnetic sensors, compared to optical sensors, have little impact on performance even when dirt adheres, and are superior in environmental resistance performance such as being usable in a wide temperature range. It is used for encoders used in motors, etc., and may be used in an ambient environment that is not good. However, since the magnetoresistive element and the electric parts on the control board may be deteriorated depending on the surrounding environment, it is desirable to store them in a package that hermetically seals them.

JP-A-6-94475 JP 2001-66151 A JP 2000-275059 A

  In the magnetic rotary encoder, the design gap dimension is determined by the characteristics of the magnetoresistive element and the shape of the magnetic pattern as described above, but is generally about several hundred μm to 1 mm. In addition, the rotating shaft of the magnetic drum causes radial runout of several tens to several hundreds of μm due to the internal clearance of a bearing or the like that restricts the displacement in the radial direction and the influence of rigidity. Under such circumstances, in order to prevent the magnetic sensor hermetically sealed with the sealing member from contacting the magnetic pattern of the magnetic drum facing the magnetic sensor, a sealing member for sealing the magnetic sensor is provided. It is necessary to make the amount protruding from the surface of the magnetic sensor as small as possible.

  As described above, in order to determine the design gap size as described above, if the position of the magnetic sensor is fine-adjusted while monitoring the output of the magnetic sensor, time is required for fine adjustment of the magnetic sensor, and high accuracy is obtained. It was necessary to make fine adjustments using this sensor. Therefore, adjustment of the design gap dimension has not been easy. In the case of a method of sandwiching a jig having a thickness corresponding to the design gap dimension between the magnetic sensor and the magnetic drum, positioning and fixing the magnetic sensor based on the jig reference, and then removing the jig, In some cases, the magnetic sensor and the magnetic drum are positioned without being arranged in parallel, and greatly deviate from the design gap dimension.

  Further, as in Patent Document 3, in the case of a structure in which the magnetic drum and the magnetic sensor are in direct contact with each other, the contact portion is worn, so that the gap size is changed or the wear powder enters the sliding portion such as the bearing. However, there is a risk of hindering the operation of the rotating mechanism.

  The present invention has been made in order to solve the above-described problems, and a magnetic type equipped with a magnetic sensor unit that can reduce the variation in the gap dimension between the magnetic sensor and the magnetic pattern by an easy method. An object of the present invention is to provide a method and an apparatus for manufacturing a rotary encoder.

  The method of manufacturing a magnetic sensor unit according to the present invention includes an opposing holding step of holding a magnetic drum facing the magnetic sensor unit and spaced apart from the magnetic sensor unit by a predetermined distance, and the magnetic sensor generated by the opposing holding step. A disposing step of disposing a planar sheet and a spacer having a protrusion on a flat plate in a space between the unit and the magnetic drum; and the magnetic sensor unit perpendicular to the planar portion of the spacer and the sheet after the disposing step A pressing step for pressing the magnetic sensor unit on the magnetic drum, a fixing step for fixing the magnetic sensor unit and the magnetic drum after the pressing step, and a removing step for removing the spacer and the sheet after the fixing step. Is.

  Further, the apparatus includes a flat sheet, a spacer having a protrusion on a flat plate, and a pressing mechanism that presses the magnetic sensor unit against the magnetic drum with the sheet and the spacer interposed therebetween.

  According to the manufacturing method and the manufacturing apparatus of the magnetic rotary encoder of the present invention, it is possible to accurately and easily reduce the variation in the gap dimension between the magnetic sensor and the magnetic pattern provided in the magnetic sensor unit of the magnetic rotary encoder. Thus, a highly accurate magnetic rotary encoder can be easily manufactured.

  A method and apparatus for manufacturing a magnetic rotary encoder including a magnetic sensor unit according to an embodiment of the present invention will be described below with reference to the drawings. In each figure, the same or similar components are denoted by the same reference numerals.

Embodiment 1 FIG.
FIG. 1 is a schematic diagram showing one scene of the manufacturing process of the magnetic rotary encoder 150 in the present embodiment. In FIG. 1, a magnetic sensor unit 120 provided with a magnetic sensor 100 is placed on a table 200. A magnetic drum 130 having a magnetic pattern 131 magnetized on the surface thereof is opposed to the magnetic sensor unit 120 by a certain distance. They are held opposite and spaced apart. A spacer 140 and a sheet 141 are disposed in the gap between the magnetic sensor unit 120 and the magnetic drum 130. A protrusion 142 is provided on the surface of the spacer 140 facing the magnetic sensor unit 120. A sensor cover 122 is provided on the surface of the magnetic sensor 100 of the magnetic sensor unit 120.

  Next, the magnetic sensor 100 shown in FIG. 1 will be described in detail with reference to FIG. FIG. 2 is a schematic diagram showing the configuration of the magnetic sensor 100. As shown in FIG. 2, the magnetic sensor 100 includes a sensor substrate 111, a magnetoresistive element 112 formed on a circuit forming surface 111 a of the sensor substrate 111, and a wiring pattern 113 electrically connected to the magnetoresistive element 112, The mount pad 114 is electrically connected to the wiring pattern 113. In addition, a magnetic sensor reference position 115 is provided at an intermediate portion between the two magnetoresistive elements 112. Here, the magnetic sensor reference position 115 is a mark formed at the center of the circuit formation surface 111 a of the sensor substrate 111 and can be seen through the sensor cover 122. Even when the magnetic sensor reference position 115 cannot be visually recognized from the outside, the position of the magnetic sensor reference position 115 may be calculated virtually from the outer dimensions.

  Next, the structure of the final magnetic rotary encoder 150 will be described with reference to FIG. As shown in FIG. 3, the magnetic sensor unit 120 includes, as a basic configuration, a sensor substrate 111, a housing 121 that holds the sensor substrate 111, and a sensor cover that covers the sensor substrate 111 held by the housing 121 and hermetically seals it. 122. The sensor cover 122 is tightly fixed to the sensor substrate 111 and the housing 121. The magnetic drum 130 is a disc formed of a non-magnetic material such as aluminum or austenitic stainless steel, and a magnetic pattern 131 is formed on the side surface of the magnetic drum 131 by magnetizing the magnetic material by vapor deposition. ing. Such a magnetic drum 130 is rotated in the circumferential direction by a rotating mechanism (not shown). Further, the magnetic pattern 131 and the magnetoresistive element 112 in the magnetic sensor unit 120 are arranged to face each other with a specified gap 145 interposed therebetween.

  Next, in the magnetic rotary encoder 150 as described above, a method of installing the magnetic sensor unit 120 and the magnetic drum 130 to face each other via the gap 145 will be described in order with reference to FIGS. 4 to 6 and FIG. .

  First, the magnetic sensor unit 120 is held on the table 200, and subsequently, as shown in FIG. The pattern 131 is temporarily arranged at a dimension position larger than the predetermined gap 145 (opposite holding step). Next, as shown in FIG. 5, the spacer 140 having the protrusion 142 and the sheet 141 are disposed in the space between the magnetic drum 130 and the magnetic sensor unit 120 (arrangement step). At this time, the spacer 140 is disposed so that the magnetic sensor reference position 115 on the magnetic sensor 100 and the protrusion 142 of the spacer 140 face each other.

  Next, as shown in FIG. 6, the pressing mechanism 144 that presses the magnetic drum 130 and the sheet 141, the sheet 141 and the spacer 140, and the protrusion 142 of the spacer 140 and the sensor cover 122 of the magnetic sensor unit 120 abut each other. Thus, the magnetic sensor unit 120 is moved in the direction perpendicular to the direction of the magnetic drum 130, that is, the plane portion of the sheet 141 and the spacer 140 (pressing step).

  In this manner, when the magnetic drum 130 and the magnetic sensor unit 120 are pressed against each other with the spacer 140 and the sheet 141 interposed therebetween, the sensor cover 122 is in contact with the sensor substrate 111. Further, the protrusion 142 of the spacer 140 is also in contact with the sensor cover 122. Therefore, the magnetic drum 130 and the magnetic sensor unit 120 are disposed via the gap 145 with the spacer 140 and the sheet 141 sandwiched therebetween. In this state, the magnetic sensor unit 120 and the magnetic drum 130 are fixed (fixing step). Thereafter, the sheet 141 is first removed, and then the spacer 140 is removed (removal process).

  By positioning and fixing the magnetic sensor unit 120 and the magnetic drum 130 according to the above-described procedure, the gap 145 between the magnetic sensor 100 and the magnetic pattern 131 can be adjusted so that the thickness of the protrusion of the spacer 140 and the thickness of the sheet 141 are reduced. This is the sum of the plate thickness and the plate thickness of the sensor cover 122. Therefore, the gap 145 is determined by the dimensions of these three parts. In this way, as shown in FIG. 3, a magnetic rotary encoder 150 in which the gap between the magnetic sensor unit 120 and the magnetic drum 130 is controlled with high accuracy can be obtained.

The spacer 140 is formed by processing a plate-like member having a protrusion 142 at the same height as the reference position 115 of the magnetic sensor and having a thickness of about several hundred μm to form the protrusion 142. The protrusion 142 is processed by chemical processing such as machining or etching, but chemical processing such as etching is preferable because it can be processed at a low cost.
Further, as shown in FIG. 1, the spacer 140 may have a bent surface 148 that surrounds the magnetic sensor unit 120 so that the horizontal position of the protrusion 142 matches the reference position 115 of the magnetic sensor 100. Good. About the dimension and bending angle of the bending surface 148, when the spacer 140 is installed in the magnetic sensor unit 120, a dimension and an angle that allow a gap of about 0.5 mm between the bending surface and the magnetic sensor unit 120 may be set. .

  The sheet 141 was a resinous plate-like jig having smooth surfaces on both surfaces and having bendability. The reason why the sheet 141 has bendability is to make it easy to pull out the sheet 141 when the sheet 141 is removed in the removing process. However, as the material of the sheet 141, the material of the spacer 140 is not a material whose plate thickness is changed by pressurization, for example, a material having high elasticity, but a rigid material. This is because the thickness of the spacer 140 and the sheet 141 is a parameter that determines the gap 145 as described above. By making the material of the spacer 140 and the sheet 141 a rigid material, the dimension of the gap 145 can be accurately determined.

  Further, as described above, the total thickness of the protrusion 140 of the spacer 140 and the thickness of the sheet 141 is set to a thickness obtained by subtracting the thickness of the sensor cover 122 from the gap 145. The plate thickness dimensions of the spacer 140 and the sheet 141 can be freely selected as long as the total plate thickness dimension becomes constant.

  Here, the roles of the protrusion 142 and the magnetic sensor reference position 115 will be described again. Even if the circuit forming surface 111a of the magnetic sensor 100 and the magnetic pattern 131 of the magnetic drum 130 are pressed in a non-parallel state by providing the protrusion 142 and the magnetic sensor reference position 115, FIG. As shown in the sectional view, the value of the gap 145 is almost the same as the value when the circuit forming surface 111a and the magnetic pattern 131 are pressed in parallel, and the thickness of the spacer 140 and the sheet 141, the sensor cover 122, and the like. It is determined only from the sum of the thickness dimensions.

  Thus, by providing the protrusion 142 and the magnetic sensor reference position 115, the circuit forming surface 111a of the magnetic sensor 100 and the magnetic pattern 131 of the magnetic drum 130 are pressed in a non-parallel state, and the magnetic sensor Even if the distance of the magnetic pattern 131 of the magnetic drum 130 is determined at a distant position, the gap 145 can be prevented from being significantly deviated from the design value. Therefore, the variation in the gap 145 can be greatly reduced as compared with the case where the protrusion 142 and the magnetic sensor reference position 115 are not provided.

  In the removal process, the sheet 141 is first removed, and then the spacer 140 is removed by first removing the sheet 141 having both surfaces smooth from a state where there is no gap, and then removing the spacer 140 having the protrusions 142. Further, the displacement of the magnetic sensor unit 120 and the magnetic drum 130 due to the removal of the sheet 141 and the spacer 140 can be prevented. Further, the spacer 140 can be used repeatedly many times without damaging the protrusion 142 of the spacer 140 having the protrusion.

  As described above, according to the manufacturing process and the manufacturing apparatus of the magnetic rotary encoder in the present embodiment, the gap size variation between the magnetic sensor and the magnetic pattern provided in the magnetic sensor unit of the magnetic rotary encoder is reduced. The magnetic rotary encoder can be accurately and easily reduced, and a highly accurate magnetic rotary encoder can be easily manufactured.

Embodiment 2. FIG.
FIG. 8 is a schematic diagram showing one scene of the manufacturing process of the magnetic rotary encoder according to the second embodiment for carrying out the present invention. As shown in FIG. 8, in this embodiment, in place of the bent surfaces 148 provided on both sides of the spacer 140 in the first embodiment, a wall 149 is provided so that the spacer is sandwiched between the walls. Except for the above, the second embodiment is the same as the first embodiment, and a detailed description thereof will be omitted.

  The magnetic rotary encoder manufacturing process and manufacturing apparatus according to the present embodiment can also accurately align the magnetic sensor unit 120 and the magnetic drum 130, and the magnetic sensor and the magnetic sensor provided in the magnetic sensor unit of the magnetic rotary encoder. Variations in the gap dimension with the pattern can be accurately and easily reduced, and a highly accurate magnetic rotary encoder can be easily manufactured.

It is a schematic diagram which shows the structure of the manufacturing method and manufacturing apparatus of the magnetic rotary encoder in Embodiment 1 of this invention. It is a schematic diagram which shows the structure of the magnetic sensor of the magnetic rotary encoder in Embodiment 1 of this invention. It is a cross-sectional schematic diagram explaining the magnetic rotary encoder in Embodiment 1 of this invention. It is a cross-sectional schematic diagram explaining 1 process of the manufacturing process of the magnetic rotary encoder in Embodiment 1 of this invention. It is a cross-sectional schematic diagram explaining 1 process of the manufacturing process of the magnetic rotary encoder in Embodiment 1 of this invention. It is a cross-sectional schematic diagram explaining 1 process of the manufacturing process of the magnetic rotary encoder in Embodiment 1 of this invention. It is a cross-sectional schematic diagram explaining 1 process of the manufacturing process of the magnetic rotary encoder in Embodiment 1 of this invention. It is a schematic diagram which shows the structure of the manufacturing method and manufacturing apparatus of the magnetic rotary encoder in Embodiment 2 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Magnetic sensor, 111 Sensor board | substrate, 112 Magnetoresistive element arrangement | positioning part, 113 Wiring pattern, 114 Mount pad, 116 Magnetic sensor reference position, 120 Magnetic sensor unit, 121 Housing, 122 Sensor cover, 130 Magnetic drum, 131 Magnetic pattern, 140 Spacer, 141 sheet, 142 protrusion, 144 pressing mechanism, 145 gap, 148 bending surface, 149 wall, 150 magnetic rotary encoder, 200 units.

Claims (7)

An opposing holding step of holding the magnetic drum facing the magnetic sensor unit and spaced apart from the magnetic sensor unit by a predetermined distance;
An arrangement step of arranging a planar sheet and a spacer having a protrusion on a flat plate in a space between the magnetic sensor unit and the magnetic drum generated by the opposing holding step;
A pressing step of pressing the magnetic sensor unit against the magnetic drum in a direction perpendicular to the spacer and the planar portion of the sheet after the arranging step;
A fixing step of fixing the magnetic sensor unit and the magnetic drum after the pressing step;
A method for manufacturing a magnetic rotary encoder, comprising: a step of removing the spacer and the sheet after the fixing step.   The magnetic sensor unit has a magnetic sensor reference position, and the magnetic sensor unit is opposed to the magnetic drum so that a protrusion of a spacer overlaps the magnetic sensor reference position of the magnetic sensor unit. A manufacturing method of the magnetic rotary encoder as described.   2. The method of manufacturing a magnetic rotary encoder according to claim 1, wherein in the removing step, the spacer is removed after the sheet is removed.   A magnetic rotary encoder comprising: a planar sheet; a spacer having a protrusion on a flat plate; and a pressing mechanism that presses the magnetic sensor unit against a magnetic drum with the sheet and the spacer interposed therebetween. Manufacturing equipment.   The apparatus for manufacturing a magnetic rotary encoder according to claim 4, wherein the surfaces on both sides of the planar sheet are smooth.   The apparatus for manufacturing a magnetic rotary encoder according to claim 4, wherein the sheet and the spacer are made of a rigid material.   The apparatus for manufacturing a magnetic rotary encoder according to claim 4, wherein the sheet has bendability.

Images