JP5333788B2

JP5333788B2 - Position sensor, manufacturing method thereof, and positioning jig

Info

Publication number: JP5333788B2
Application number: JP2010221286A
Authority: JP
Inventors: 良一毛受; 俊彦大山
Original assignee: TDK Corp
Current assignee: TDK Corp
Priority date: 2010-09-30
Filing date: 2010-09-30
Publication date: 2013-11-06
Anticipated expiration: 2030-09-30
Also published as: JP2012078123A

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position sensor including a plurality of magnetically sensitive elements positioned more accurately as compared with a conventional case for performing positioning by a recess of a holder, to provide a manufacturing method of the position sensor, and to provide a positioning tool capable of performing positioning more accurately as compared with a conventional tool. <P>SOLUTION: The positioning of a plurality of magnetically sensitive elements 10 each having a lead terminal 12 to a circuit board 20 and mutually relative positioning of the magnetically sensitive elements 10 are previously performed at high accuracy by a metallic positioning tool e.g. allowed to be formed by highly accurate external dimensions as compared with resin before storing the magnetically sensitive elements 10 in a case 30. An element storing recess 32 of the case 30 is sufficiently large in a degree that the positions of the magnetically sensitive elements 10 are not regulated. <P>COPYRIGHT: (C)2012,JPO&INPIT

Description

本発明は、例えば直線移動又は回転移動する永久磁石の移動状態を複数の磁気感応素子で磁気的に検知する場合等に用いる位置センサ及びその製造方法、並びに複数の磁気感応素子を回路基板に対して位置決めするのに好適な位置決め治具に関する。 The present invention relates to a position sensor used when, for example, a movement state of a permanent magnet that moves linearly or rotationally is magnetically detected by a plurality of magnetic sensitive elements, a manufacturing method thereof, and a plurality of magnetic sensitive elements to a circuit board. The present invention relates to a positioning jig suitable for positioning.

例えば下記特許文献１に示される移動物体検出装置は、ホルダのくぼみ部に磁気感応素子を保持し、この磁気感応素子のリード端子を基板に接続している。すなわち、ホルダのくぼみ部が磁気感応素子を位置決めする。 For example, in a moving object detection device shown in Patent Document 1 below, a magnetic sensitive element is held in a recessed portion of a holder, and a lead terminal of the magnetic sensitive element is connected to a substrate. That is, the recessed portion of the holder positions the magnetic sensitive element.

特開２００６−３０８４３５号公報JP 2006-308435 A

ホルダは一般に樹脂成型により作られるため、金型のキャビ違いや成型公差、成型条件の違い等によりホルダの形状がわずかに変わってしまう。このため、ホルダのくぼみ部により磁気感応素子を位置決めする特許文献１の構成では、くぼみ部の位置がわずかにずれることにより、磁気感応素子の位置すなわちセンシングポイントもずれてしまう。そうすると、特に、多相出力が必要で複数の磁気感応素子を設ける場合には、複数の磁気感応素子の相対位置がずれるため、検出精度が悪化するという問題がある。 Since the holder is generally made by resin molding, the shape of the holder slightly changes due to differences in mold cavities, molding tolerances, molding conditions, and the like. For this reason, in the structure of patent document 1 which positions a magnetic sensitive element by the hollow part of a holder, the position of a magnetic sensitive element, ie, a sensing point, will also shift, when the position of a hollow part shifts slightly. Then, in particular, when a multi-phase output is required and a plurality of magnetic sensitive elements are provided, there is a problem that the detection accuracy is deteriorated because the relative positions of the magnetic sensitive elements are shifted.

本発明はこうした状況を認識してなされたものであり、その目的は、従来のようにホルダのくぼみ部により位置決めする場合と比較して、複数の磁気感応素子をより正確に位置決めできる構成の位置センサ及びその製造方法、並びに従来より正確な位置決めを可能とする位置決め治具を提供することにある。 The present invention has been made in view of such a situation, and the object of the present invention is to provide a position in which a plurality of magnetically sensitive elements can be positioned more accurately than in the conventional case where positioning is performed by a recessed portion of a holder. It is an object of the present invention to provide a sensor, a manufacturing method thereof, and a positioning jig that enables more accurate positioning than in the past.

本発明の第１の態様は、位置センサである。この位置センサは、
各々がリード端子を有する複数の磁気感応素子と、前記複数の磁気感応素子に対して共通に設けられ各リード端子が接続固定された回路基板と、前記回路基板を位置決め保持するケースとを備え、
前記ケースは、前記回路基板を搭載する基板搭載面と、前記基板搭載面から凹む素子収容凹部とを有し、
前記複数の磁気感応素子は、相互に位置決めされた状態で各々のリード端子が前記回路基板に接続固定され、本体部が前記素子収容凹部内に位置し、
前記素子収容凹部が、前記複数の磁気感応素子の位置を規制しないことを特徴とする。 The first aspect of the present invention is a position sensor. This position sensor
A plurality of magnetic sensitive elements each having a lead terminal; a circuit board provided in common to the plurality of magnetic sensitive elements to which each lead terminal is connected and fixed; and a case for positioning and holding the circuit board,
The case has a substrate mounting surface on which the circuit board is mounted, and an element receiving recess recessed from the substrate mounting surface,
Each of the plurality of magnetically sensitive elements is fixedly connected to the circuit board in a state where the plurality of magnetically sensitive elements are positioned with respect to each other, and a main body portion is located in the element receiving recess,
The element housing recess, wherein the go, such regulate the positions of the plurality of magnetically sensitive elements.

本発明の第２の態様は、位置センサ製造方法である。この方法は、
各々がリード端子を有する複数の磁気感応素子を回路基板に対して位置決め治具を用いて位置決めした状態を維持しながら、各リード端子を前記回路基板に接続固定する接続工程と、
前記接続工程の後に、前記複数の磁気感応素子及び前記回路基板をケースに収容する収容工程とを含む。 A second aspect of the present invention is a position sensor manufacturing method. This method
A connection step of connecting and fixing each lead terminal to the circuit board while maintaining a state in which a plurality of magnetic sensitive elements each having a lead terminal are positioned with respect to the circuit board using a positioning jig;
A housing step of housing the plurality of magnetically sensitive elements and the circuit board in a case after the connecting step;

第２の態様の方法において、前記位置決め治具は、
台部と、前記台部の縁から下方に延びる側壁と、前記側壁から凹み且つ３つの位置規制面を有し、上方が開放である複数の位置決め用凹部と、前記位置決め用凹部に対して相対移動可能なプッシャーとを有し、
前記接続工程では、前記回路基板を前記台部に搭載し、前記磁気感応素子の３つの側面を前記３つの位置規制面で支持しながら、前記磁気感応素子の側面のうち前記位置規制面の対面していない側面を前記プッシャーで前記位置決め用凹部に向けて押し付けるとよい。 In the method of the second aspect, the positioning jig is
Relative to the positioning recess, the side wall extending downward from the edge of the base portion, the plurality of positioning recesses recessed from the side wall and having three position restricting surfaces, the upper part being open A movable pusher,
In the connecting step, the circuit board is mounted on the pedestal, and the three side surfaces of the magnetic sensitive element are supported by the three position restricting surfaces, and the position restricting surface of the side surfaces of the magnetic sensitive element faces each other. It is preferable to press a side surface that is not directed toward the positioning concave portion with the pusher.

第２の態様の方法において、
前記ケースは、基板搭載面と、前記基板搭載面から凹む素子収容凹部とを有し、
前記素子収容凹部は、前記複数の磁気感応素子の位置を規制しない程度に十分大きく、
前記収容工程では、前記回路基板を前記基板搭載面上に位置決めし、かつ前記複数の磁気感応素子の本体部を前記素子収容凹部内に位置させるとよい。 In the method of the second aspect,
The case has a substrate mounting surface and an element receiving recess recessed from the substrate mounting surface,
The element accommodating recess is sufficiently large so as not to regulate the positions of the plurality of magnetically sensitive elements,
In the housing step, the circuit board may be positioned on the board mounting surface, and the main body portions of the plurality of magnetically sensitive elements may be positioned in the element housing recesses.

この場合、前記収容工程では、前記基板搭載面から突出したガイドピンを前記回路基板の位置決め穴に通し、前記回路基板を前記基板搭載面上に位置決め固定するとよい。 In this case, in the housing step, it is preferable that the guide pin protruding from the board mounting surface is passed through the positioning hole of the circuit board, and the circuit board is positioned and fixed on the board mounting surface.

第２の態様の方法において、各リード端子を所定位置で折り曲げて先端側に折曲げ部を形成しておき、前記接続工程では前記折曲げ部を前記回路基板に接続固定するとよい。 In the method of the second aspect, each lead terminal may be bent at a predetermined position to form a bent portion on the tip side, and in the connecting step, the bent portion may be connected and fixed to the circuit board.

第２の態様の方法において、前記収容工程の後に、前記ケース内を絶縁樹脂で封止するとよい。 In the method of the second aspect, the inside of the case may be sealed with an insulating resin after the housing step.

本発明の第３の態様は、位置決め治具である。この位置決め治具は、
各々がリード端子を有する複数の磁気感応素子を回路基板に対して位置決め可能な位置決め治具であって、
回路基板を搭載する台部と、
前記台部の縁から下方に延びる側壁と、
前記側壁から凹み、磁気感応素子の３つの側面に当接する位置規制面を有し、上方が開放である複数の位置決め用凹部と、
前記位置決め用凹部に位置する磁気感応素子の側面のうち前記位置規制面の対面していない側面を前記位置決め用凹部に向けて押付け可能に前記位置決め用凹部に対して相対移動するプッシャーとを備える。 A third aspect of the present invention is a positioning jig. This positioning jig
A positioning jig capable of positioning a plurality of magnetically sensitive elements each having a lead terminal with respect to a circuit board,
A base for mounting a circuit board;
A side wall extending downward from an edge of the platform;
A plurality of positioning recesses that are recessed from the side wall, have position restricting surfaces that abut against the three side surfaces of the magnetically sensitive element, and are open at the top;
A pusher that moves relative to the positioning recess so as to be able to press a side surface of the magnetically sensitive element positioned in the positioning recess that is not facing the position regulating surface toward the positioning recess;

第３の態様の位置決め治具において、この位置決め治具は、樹脂よりも高精度の外形寸法で形成可能な樹脂以外の材質であるとよい。 In the positioning jig of the third aspect, the positioning jig may be made of a material other than resin that can be formed with an outer dimension with higher accuracy than resin.

なお、以上の構成要素の任意の組合せ、本発明の表現をシステムなどの間で変換したものもまた、本発明の態様として有効である。 It should be noted that any combination of the above-described constituent elements, or a conversion of the expression of the present invention between systems or the like is also effective as an aspect of the present invention.

本発明によれば、従来のようにホルダのくぼみ部により位置決めする場合と比較して、複数の磁気感応素子をより正確に位置決めできる構成の位置センサ及びその製造方法、並びに従来より正確な位置決めを可能とする位置決め治具を実現することができる。 According to the present invention, compared to the conventional positioning by the recessed portion of the holder, a position sensor having a configuration capable of positioning a plurality of magnetically sensitive elements more accurately, a manufacturing method thereof, and more accurate positioning than the conventional one. An enabling positioning jig can be realized.

本発明の実施の形態に係る位置センサの製造方法の流れを示す概略工程図。The schematic process drawing which shows the flow of the manufacturing method of the position sensor which concerns on embodiment of this invention. 同方法における、磁気感応素子及び回路基板の位置決め手順説明図。The positioning procedure explanatory drawing of a magnetic sensitive element and a circuit board in the same method. 前記位置センサに用いる磁気感応素子の概略斜視図。The schematic perspective view of the magnetic sensitive element used for the said position sensor. 磁気感応素子及び回路基板の位置決めに用いる位置決め治具の概略斜視図。The schematic perspective view of the positioning jig used for positioning of a magnetic sensitive element and a circuit board. 磁気感応素子及び回路基板を収容したケースに外部接続用のコネクタを取り付けた平面図。The top view which attached the connector for external connection to the case which accommodated the magnetic sensitive element and the circuit board. ケースの素子収容凹部の形状のバリエーションを示す平面図。The top view which shows the variation of the shape of the element accommodating recessed part of a case.

以下、図面を参照しながら本発明の好適な実施の形態を詳述する。なお、各図面に示される同一または同等の構成要素、部材等には同一の符号を付し、適宜重複した説明は省略する。また、実施の形態は発明を限定するものではなく例示であり、実施の形態に記述されるすべての特徴やその組み合わせは必ずしも発明の本質的なものであるとは限らない。 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

図１は、本発明の実施の形態に係る位置センサの製造方法の流れを示す概略工程図である。図２は、同方法における、磁気感応素子１０及び回路基板２０の位置決め手順説明図である。図３は、前記位置センサに用いる磁気感応素子１０の概略斜視図である。図４は、磁気感応素子１０及び回路基板２０の位置決めに用いる位置決め治具５０の概略斜視図である。図５は、磁気感応素子１０及び回路基板２０を収容したケース３０に外部接続用のコネクタ７５を取り付けた平面図である。 FIG. 1 is a schematic process diagram showing a flow of a manufacturing method of a position sensor according to an embodiment of the present invention. FIG. 2 is an explanatory view of the positioning procedure of the magnetic sensitive element 10 and the circuit board 20 in the same method. FIG. 3 is a schematic perspective view of the magnetic sensitive element 10 used for the position sensor. FIG. 4 is a schematic perspective view of a positioning jig 50 used for positioning the magnetically sensitive element 10 and the circuit board 20. FIG. 5 is a plan view in which a connector 75 for external connection is attached to the case 30 that houses the magnetic sensitive element 10 and the circuit board 20.

本実施の形態では、磁気感応素子１０を回路基板２０に対して位置決め固定する接続工程（図１（Ａ）→（Ｂ））の実行後に、磁気感応素子１０及び回路基板２０をケース３０に収容する（図１（Ｂ）→（Ｃ））。すなわち、あらかじめ磁気感応素子１０及び回路基板２０を相互に位置決めした上で両者をケース３０に収容する。このため、ケース３０の素子収容凹部３２は、従来と異なり、磁気感応素子１０の位置を直接規制しない構造とする。以下、位置センサの各部材の構成を説明し、その後、位置センサの製造方法について説明する。 In the present embodiment, the magnetic sensitive element 10 and the circuit board 20 are accommodated in the case 30 after the connection process (FIG. 1 (A) → (B)) for positioning and fixing the magnetic sensitive element 10 to the circuit board 20 is performed. (FIG. 1 (B) → (C)). That is, after the magnetic sensitive element 10 and the circuit board 20 are positioned in advance, both are accommodated in the case 30. For this reason, unlike the conventional case, the element receiving recess 32 of the case 30 has a structure that does not directly restrict the position of the magnetic sensitive element 10. Hereinafter, the configuration of each member of the position sensor will be described, and then the method for manufacturing the position sensor will be described.

図３に示すように、例えばホールＩＣである磁気感応素子１０は、感磁面を内蔵する本体部１１からリード端子１２が突出した構造である。リード端子１２は、例えばＬ字状に折り曲げられていて、先端部が折曲げ部１２ａとなっている。本実施の形態の位置センサは、例えば三相モータの角度センサであり、図１に示すようにＵ，Ｖ，Ｗの各相の制御用に磁気感応素子１０を合計３つ使用する。 As shown in FIG. 3, the magnetic sensitive element 10 which is, for example, a Hall IC has a structure in which a lead terminal 12 protrudes from a main body 11 containing a magnetic sensitive surface. The lead terminal 12 is bent, for example, in an L shape, and a tip end portion is a bent portion 12a. The position sensor of the present embodiment is, for example, an angle sensor of a three-phase motor, and uses a total of three magnetically sensitive elements 10 for controlling each phase of U, V, and W as shown in FIG.

図１（Ａ）に示すように、回路基板２０は、曲線状縁部２０ａの近傍に導体からなる電極部２１を有する。電極部２１は、各々の磁気感応素子１０に対応して３箇所に設けられている。図１（Ｃ）に示すように、角度検出の対象物の例示であるリングマグネット８０の回転軸８１と、隣り合う電極部２１とを結んだ仮想線の成す角度は、例えば３０°である。また、各々の電極部２１と回転軸８１との距離は好ましくは等しいものとする。図１（Ａ）に示すように、曲線状縁部２０ａは、内側に湾曲した例えば円弧状であり、使用時にはリングマグネット８０の外周面に各部が等距離で対面する形状であるとよい。２つの位置決め穴２０１は、後述のケース３０のガイドピン３０１を通すものである。 As shown in FIG. 1A, the circuit board 20 has an electrode portion 21 made of a conductor in the vicinity of the curved edge portion 20a. The electrode portion 21 is provided at three locations corresponding to each magnetic sensitive element 10. As shown in FIG. 1C, the angle formed by the imaginary line connecting the rotating shaft 81 of the ring magnet 80, which is an example of the object of angle detection, and the adjacent electrode portion 21 is, for example, 30 °. The distance between each electrode portion 21 and the rotation shaft 81 is preferably equal. As shown in FIG. 1A, the curved edge portion 20a is, for example, an arc shape that is curved inward, and it is preferable that each portion face the outer peripheral surface of the ring magnet 80 at an equal distance when used. The two positioning holes 201 are for passing guide pins 301 of the case 30 described later.

図１（Ｂ）に示すように、例えば絶縁樹脂製のケース３０は、基板搭載面３１と、素子収容凹部３２と、グロメット用凹部３３と、２本のガイドピン３０１と、側壁部３１１〜３１４とを有する。 As shown in FIG. 1B, for example, an insulating resin case 30 includes a substrate mounting surface 31, an element housing recess 32, a grommet recess 33, two guide pins 301, and side wall portions 311 to 314. And have.

平面である基板搭載面３１は、角度検出の対象物（例えば図１（Ｃ）のリングマグネット８０）が存在する方向の辺が、回路基板２０の曲線状縁部２０ａと同様に曲がった曲線状辺部３１ａとなっている。素子収容凹部３２は、例えば円弧状等の曲線状穴（スリット）であり、基板搭載面３１の曲線状辺部３１ａから凹む。素子収容凹部３２は、３つの磁気感応素子１０を一括に収容可能な大きさであり、かつ磁気感応素子１０の位置を規制しない程度に十分大きい。例えば、磁気感応素子１０の本体部１１がいずれの面も素子収容凹部３２の内面に当接することなく素子収容凹部３２内に位置し得る程度に素子収容凹部３２は大きい。 The substrate mounting surface 31 that is a plane has a curved shape in which a side in a direction in which an object for angle detection (for example, the ring magnet 80 in FIG. 1C) exists is bent in the same manner as the curved edge portion 20 a of the circuit board 20. It is the side part 31a. The element accommodating recess 32 is a curved hole (slit) such as an arc shape, and is recessed from the curved side portion 31 a of the substrate mounting surface 31. The element accommodating recess 32 is large enough to accommodate the three magnetic sensitive elements 10 at a time, and is large enough not to restrict the position of the magnetic sensitive element 10. For example, the element receiving recess 32 is large enough that the main body 11 of the magnetic sensitive element 10 can be positioned in the element receiving recess 32 without any surface coming into contact with the inner surface of the element receiving recess 32.

グロメット用凹部３３は、図５で後述のグロメット７１が延在可能なように、基板搭載面３１の曲線状辺部３１ａと反対側の直線状辺部３１ｂから凹む。側壁部３１１〜３１４は、基板搭載面３１、素子収容凹部３２及びグロメット用凹部３３を囲むように立ち上がる。側壁部３１１は、使用時にリングマグネット８０の外周面と対面するもので、回路基板２０の曲線状縁部２０ａと同様に湾曲した曲面状（例えば円弧面状等の凹面）である。側壁部３１４の中間部は、両端部よりも凹んだ（高さが低い）低背部３１４ａとなっている。これは、図５で後述のグロメット７１の取付け（嵌合）のためである。 The grommet recess 33 is recessed from the linear side 31b opposite to the curved side 31a of the substrate mounting surface 31 so that a grommet 71 described later in FIG. 5 can extend. The side wall portions 311 to 314 rise so as to surround the substrate mounting surface 31, the element housing recess 32 and the grommet recess 33. The side wall portion 311 faces the outer peripheral surface of the ring magnet 80 during use, and has a curved surface (for example, a concave surface such as an arc surface) that is curved in the same manner as the curved edge portion 20a of the circuit board 20. An intermediate portion of the side wall portion 314 is a low-back portion 314a that is recessed (lower in height) than both end portions. This is for attaching (fitting) a grommet 71 described later in FIG.

基板搭載面３１から突出する２本のガイドピン３０１は、回路基板２０の上述の位置決め穴２０１に嵌って回路基板２０を基板搭載面３１上で位置決めする。なお、好ましくはガイドピン３０１の突出長さは、磁気感応素子１０の高さ（本体部１１とリード端子１２の合計高さ）と同じかそれより長いとよい。すなわち、回路基板２０の位置決め穴２０１がガイドピン３０１の先端に係合しているときに、回路基板２０に固定された磁気感応素子１０の本体部１１が素子収容凹部３２内に入らない程度にガイドピン３０１の突出長さを長くする。また、ガイドピン３０１は、好ましくは先端近傍をテーパー状として回路基板２０の位置決め穴２０１を挿通容易とする。 The two guide pins 301 protruding from the board mounting surface 31 fit into the positioning holes 201 of the circuit board 20 to position the circuit board 20 on the board mounting surface 31. Preferably, the protruding length of the guide pin 301 is equal to or longer than the height of the magnetic sensing element 10 (the total height of the main body 11 and the lead terminal 12). That is, when the positioning hole 201 of the circuit board 20 is engaged with the tip of the guide pin 301, the main body part 11 of the magnetic sensitive element 10 fixed to the circuit board 20 does not enter the element housing recess 32. The protruding length of the guide pin 301 is increased. Further, the guide pin 301 preferably has a tapered shape in the vicinity of the tip to facilitate insertion of the positioning hole 201 of the circuit board 20.

続いて、３つの磁気感応素子１０を回路基板２０に対して位置決め固定する際に用いる位置決め治具５０の構成例を説明する。 Next, a configuration example of the positioning jig 50 used when positioning and fixing the three magnetic sensitive elements 10 to the circuit board 20 will be described.

図２及び図４に示すように、例えば金属製（鉄製やアルミ合金製等）の位置決め治具５０は、台部５１と、側壁５２ａ〜５２ｃと、位置決め用凹部５３と、プッシャー５５と、ガイド部５６とを備える。台部５１は、回路基板２０を搭載する平面である。台部５１から突出する２本のガイドピン５０１を回路基板２０の上述の位置決め穴２０１に嵌合することで、回路基板２０を台部５１上で位置決めする。 As shown in FIGS. 2 and 4, for example, a metal (such as iron or aluminum alloy) positioning jig 50 includes a base 51, side walls 52a to 52c, a positioning recess 53, a pusher 55, and a guide. Part 56. The base 51 is a plane on which the circuit board 20 is mounted. By fitting the two guide pins 501 protruding from the pedestal 51 into the positioning holes 201 of the circuit board 20, the circuit board 20 is positioned on the pedestal 51.

側壁５２ａ〜５２ｃは、台部５１の縁から下方に延び、相互に所定の角度を成す。この角度は、３つの磁気感応素子１０の感磁面が相互に成すべき角度に対応する。３つの位置決め用凹部５３は、側壁５２ａ〜５２ｃから凹む。各々の位置決め用凹部５３は、磁気感応素子１０の３つの側面に当接してその位置を規制する位置規制面５３ａ〜５３ｃと、磁気感応素子１０の底面（又は上面）と当接してその位置を規制する底面５３ｄとを有する。一方、各々の位置決め用凹部５３は、位置規制面５３ｂの対向する側方と、上方とが開放である。なお、各々の位置決め用凹部５３は、位置規制面５３ａ〜５３ｃの上端から上方側の側面がそれぞれ外側に（上部開口が広がる向きに）傾斜しており、磁気感応素子１０の位置決め時に磁気感応素子１０を挿入容易としている。 The side walls 52a to 52c extend downward from the edge of the base 51 and form a predetermined angle with each other. This angle corresponds to the angle that the magnetic sensitive surfaces of the three magnetic sensitive elements 10 should form with each other. The three positioning recesses 53 are recessed from the side walls 52a to 52c. Each positioning recess 53 abuts against the three side surfaces of the magnetic sensing element 10 to regulate its position and the bottom surface (or top surface) of the magnetic sensing element 10 to abut the position. And a bottom surface 53d to be regulated. On the other hand, each of the positioning recesses 53 is open on the opposite side and upper side of the position regulating surface 53b. Each positioning recess 53 has an upper side surface inclined from the upper end of the position regulating surfaces 53a to 53c to the outside (in the direction in which the upper opening widens), and the magnetic sensitive element 10 is positioned when the magnetic sensitive element 10 is positioned. 10 is easy to insert.

プッシャー５５は、側壁５２ａ〜５２ｃと平行な当接面５５ａ〜５５ｃを有する。そして、プッシャー５５は、磁気感応素子１０の位置決め時には、位置決め用凹部５３に位置する磁気感応素子１０の側面のうち位置規制面５３ａ〜５３ｃの対面していない側面を位置決め用凹部５３に向けて当接面５５ａ〜５５ｃで押付け可能なように位置決め用凹部５３に対して相対移動可能である。この相対移動は、例えばレール５７に沿ってプッシャー５５がスライドすることで実現される。台部５１と一体でプッシャー５５の両側に位置するガイド部５６は、プッシャー５５の横方向（スライド方向と垂直な方向）の位置ずれを防止するようにプッシャー５５をガイドする。 The pusher 55 has contact surfaces 55a to 55c parallel to the side walls 52a to 52c. When the magnetic sensitive element 10 is positioned, the pusher 55 applies the side surfaces of the magnetic sensitive element 10 positioned in the positioning concave portion 53 that are not facing the position restricting surfaces 53 a to 53 c toward the positioning concave portion 53. It can move relative to the positioning recess 53 so that it can be pressed by the contact surfaces 55a to 55c. This relative movement is realized by the pusher 55 sliding along the rail 57, for example. The guide portions 56 that are integrated with the base portion 51 and are located on both sides of the pusher 55 guide the pusher 55 so as to prevent displacement of the pusher 55 in the lateral direction (direction perpendicular to the sliding direction).

以下、位置センサの製造方法について説明する。 Hereinafter, a method for manufacturing the position sensor will be described.

１．接続工程（図１（Ａ）→（Ｂ）、及び図２）
各々がリード端子１２を有する３つの磁気感応素子１０を、回路基板２０に対して位置決め治具５０を用いて位置決めする。そして、位置決め状態を維持しながら、各リード端子１２の折曲げ部１２ａ（図３参照）を回路基板２０の電極部２１に例えば半田付け等で接続固定する。ここで、位置決め治具５０による位置決めの際には、図２に示すように、回路基板２０の位置決め穴２０１を台部５１のガイドピン５０１と嵌め合わせて回路基板２０を台部５１に位置決め搭載し、磁気感応素子１０を位置決め用凹部５３に上から挿入する。そして、磁気感応素子１０の３つの側面を位置規制面５３ａ〜５３ｃで支持しながら、磁気感応素子１０の側面のうち位置規制面５３ａ〜５３ｃの対面していない側面をプッシャー５５で位置決め用凹部５３に向けて押し付ける。これにより、回路基板２０に対して磁気感応素子１０が正確に位置決めされる。また、磁気感応素子１０同士の相対位置関係も正確に定められる。 1. Connection process (FIG. 1 (A) → (B) and FIG. 2)
The three magnetic sensitive elements 10 each having the lead terminal 12 are positioned with respect to the circuit board 20 by using a positioning jig 50. And the bending part 12a (refer FIG. 3) of each lead terminal 12 is connected and fixed to the electrode part 21 of the circuit board 20 by soldering etc., maintaining a positioning state. Here, at the time of positioning by the positioning jig 50, as shown in FIG. 2, the positioning hole 201 of the circuit board 20 is fitted with the guide pin 501 of the base part 51, and the circuit board 20 is positioned and mounted on the base part 51. Then, the magnetic sensitive element 10 is inserted into the positioning recess 53 from above. Then, while supporting the three side surfaces of the magnetic sensitive element 10 by the position regulating surfaces 53 a to 53 c, the positioning concave portion 53 is formed by the pusher 55 on the side surface of the magnetic sensitive element 10 that is not facing the position regulating surfaces 53 a to 53 c. Press toward. Thereby, the magnetic sensitive element 10 is accurately positioned with respect to the circuit board 20. Further, the relative positional relationship between the magnetic sensitive elements 10 is also accurately determined.

２．収容工程（図１（Ｂ）→（Ｃ））
前記接続工程の後に、３つの磁気感応素子１０及び回路基板２０をケース３０に収容する。具体的には、まず、回路基板２０の位置決め穴２０１を基板搭載面３１から突出したガイドピン３０１の先端に係合させる。その後、回路基板２０をガイドピン３０１に沿って下降させ、ガイドピン３０１と嵌合により回路基板２０を基板搭載面３１上に位置決めするとともに、３つの磁気感応素子１０の本体部１１を素子収容凹部３２内に位置させる。なお、好ましくは、熱溶着用コテ４０によるガイドピン３０１の熱溶着により回路基板２０を基板搭載面３１上に位置決め固定する。また、ガイドピン３０１の熱溶着前に、ガイドピン３０１を中間部で切断して所定長に短くしてもよい。 2. Accommodation process (FIG. 1 (B) → (C))
After the connecting step, the three magnetic sensitive elements 10 and the circuit board 20 are accommodated in the case 30. Specifically, first, the positioning hole 201 of the circuit board 20 is engaged with the tip of the guide pin 301 protruding from the board mounting surface 31. Thereafter, the circuit board 20 is lowered along the guide pins 301, the circuit board 20 is positioned on the board mounting surface 31 by fitting with the guide pins 301, and the main body portions 11 of the three magnetic sensitive elements 10 are placed in the element receiving recesses. 32. Preferably, the circuit board 20 is positioned and fixed on the board mounting surface 31 by heat welding of the guide pins 301 by the hot welding iron 40. Further, the guide pin 301 may be cut at the intermediate portion to shorten it to a predetermined length before the guide pin 301 is thermally welded.

３．コネクタ取付け工程（図１（Ｃ）→図５）
前記収容工程の後に、ケース３０の側壁３１４の低背部３１４ａ（図１（Ｃ）参照）にグロメット７１を嵌合させて取り付ける（図５参照）。グロメット７１を貫通するコード７２（ここでは５本）の一端を回路基板２０に接続固定する。コード７２の中間部はチューブ７４で被覆保護され、コード７２の他端は外部接続用のコネクタ７５となっている。コネクタ７５は、例えば自動車等のＥＣＵ（Electric Control Unit）に接続される。なお、好ましくは、グロメット７１の取付け後に、ケース３０に絶縁樹脂（エポキシ等の注型材）を注入して磁気感応素子１０及び回路基板２０をケース３０内で固定する（封止する）。 3. Connector installation process (Fig. 1 (C) → Fig. 5)
After the housing step, the grommet 71 is fitted and attached to the low profile portion 314a (see FIG. 1C) of the side wall 314 of the case 30 (see FIG. 5). One end of a cord 72 (five here) penetrating the grommet 71 is connected and fixed to the circuit board 20. An intermediate portion of the cord 72 is covered and protected by a tube 74, and the other end of the cord 72 is a connector 75 for external connection. The connector 75 is connected to an ECU (Electric Control Unit) such as an automobile. Preferably, after the grommet 71 is attached, an insulating resin (a casting material such as epoxy) is injected into the case 30 to fix (seal) the magnetic sensitive element 10 and the circuit board 20 in the case 30.

本実施の形態によれば、下記の効果を奏することができる。 According to the present embodiment, the following effects can be achieved.

(1) 回路基板２０に対する磁気感応素子１０の位置決め、及び磁気感応素子１０同士の相対的な位置決めを、樹脂よりも高精度の外形寸法で形成可能な例えば金属製の位置決め治具５０によって、ケース３０への収容前に予め高精度に行っている。そして、ケース３０の素子収容凹部３２は、磁気感応素子１０の位置を規制しない程度に十分大きいものとしている。このため、従来のように樹脂成型により作られたホルダのくぼみ部により磁気感応素子を位置決めする構成と異なり、金型のキャビ違いや成型公差、成型条件の違い等による形状変化によって複数の磁気感応素子の相対位置がずれることを防止可能であり、高精度の位置検出を実現することができる。すなわち、ケース３０の素子収容凹部３２の位置精度に依存しない高いセンサ精度を実現可能である。 (1) For example, a metal positioning jig 50 capable of positioning the magnetic sensitive elements 10 with respect to the circuit board 20 and the relative positioning of the magnetic sensitive elements 10 with an external dimension with higher accuracy than that of a resin. This is performed in advance with high accuracy before being accommodated in the 30. The element receiving recess 32 of the case 30 is sufficiently large so as not to restrict the position of the magnetic sensitive element 10. For this reason, unlike the conventional configuration in which the magnetically sensitive element is positioned by the recessed portion of the holder made by resin molding, a plurality of magnetic sensitive elements are caused by shape changes caused by mold cavities, molding tolerances, molding conditions, etc. It is possible to prevent the relative positions of the elements from shifting and to realize highly accurate position detection. That is, it is possible to realize high sensor accuracy that does not depend on the positional accuracy of the element housing recess 32 of the case 30.

(2) ケース３０の素子収容凹部３２が磁気感応素子１０の位置を規制しない程度に十分大きいため、３つの磁気感応素子１０及び回路基板２０をケース３０に収容する際に、３つの磁気感応素子１０の本体部１１を素子収容凹部３２内に位置させる作業性が良好である。この点、従来のようにホルダのくぼみ部により磁気感応素子を位置決めする場合は、くぼみ部を狭公差にして（可能な限り小さくして）ぎりぎりの寸法のところに磁気感応素子を収容する必要があり、収容作業の難易度が高い。このため、収容作業中に作業者が磁気感応素子のリード端子を不用意に曲げてしまうことがあり、リード端子の曲げ精度が悪化してリード端子が回路基板に対して浮いてしまう等、信頼性が低下する問題がある。これに対し、本実施の形態では、上記のように素子収容凹部３２が大きく磁気感応素子１０及び回路基板２０のケース３０への収容作業性が良いため、作業者がリード端子１２を不用意に折り曲げてしまうリスクは低く、従来のような信頼性低下の問題は少ないといえる。 (2) Since the element receiving recess 32 of the case 30 is sufficiently large so as not to restrict the position of the magnetic sensitive element 10, the three magnetic sensitive elements are accommodated when the three magnetic sensitive elements 10 and the circuit board 20 are accommodated in the case 30. The workability of positioning the ten main body portions 11 in the element accommodating recess 32 is good. In this regard, when positioning the magnetically sensitive element by the recessed part of the holder as in the prior art, it is necessary to accommodate the magnetically sensitive element at a marginal dimension with the recessed part having a narrow tolerance (as small as possible). Yes, the containment work is difficult. For this reason, the operator may inadvertently bend the lead terminal of the magnetically sensitive element during the housing operation, and the lead terminal may be bent with respect to the circuit board due to deterioration of the bending accuracy of the lead terminal. There is a problem that the performance decreases. On the other hand, in the present embodiment, as described above, the element receiving recess 32 is large and the workability of housing the magnetic sensitive element 10 and the circuit board 20 in the case 30 is good. The risk of bending is low, and it can be said that there are few problems of lowering reliability as in the past.

(3) ケース３０の素子収容凹部３２が磁気感応素子１０の位置を規制しない程度に十分大きいため、磁気感応素子１０がぴったり嵌る程度に素子収容凹部３２が小さい場合と比較して、ケース３０の樹脂封止時の気泡の発生を抑えることができる。気泡が表面に上がってくると製品としての外観を損ない、気泡が内部に留まると熱膨張により磁気感応素子１０や回路基板２０を不用意に圧迫して信頼性に問題が生じうるところ、本実施の形態では上記のように気泡の発生を抑えることが可能なため、気泡の発生に伴う不具合を好適に低減できる。 (3) Since the element receiving recess 32 of the case 30 is sufficiently large so as not to restrict the position of the magnetic sensing element 10, the case receiving recess 32 of the case 30 is smaller than the case where the element receiving recess 32 is small enough to fit the magnetic sensing element 10 exactly. The generation of bubbles during resin sealing can be suppressed. If the bubbles rise on the surface, the appearance of the product is impaired, and if the bubbles stay inside, the magnetic sensitive element 10 and the circuit board 20 may be carelessly pressed due to thermal expansion, causing a problem in reliability. In this embodiment, since it is possible to suppress the generation of bubbles as described above, problems associated with the generation of bubbles can be suitably reduced.

(4) ガイドピン３０１の突出長さが磁気感応素子１０の高さ（本体部１１とリード端子１２の合計高さ）と同じかそれより長いため、磁気感応素子１０及び回路基板２０をケース３０に収容する際には、まず回路基板２０の位置決め穴２０１をケース３０のガイドピン３０１の先端に係合させてから、回路基板２０をガイドピン３０１に沿って下降させることで磁気感応素子１０を素子収容凹部３２内に位置させる流れとなり、作業者が磁気感応素子１０の本体部を素子収容凹部３２の内壁に誤って当ててリード端子１２を不用意に折り曲げることを防止できる。 (4) Since the protruding length of the guide pin 301 is equal to or longer than the height of the magnetic sensitive element 10 (the total height of the main body 11 and the lead terminal 12), the magnetic sensitive element 10 and the circuit board 20 are attached to the case 30. When the magnetic sensing element 10 is received, the positioning hole 201 of the circuit board 20 is first engaged with the tip of the guide pin 301 of the case 30 and then the circuit board 20 is lowered along the guide pin 301. Thus, the operator can prevent the lead terminal 12 from being inadvertently bent by accidentally applying the main body of the magnetically sensitive element 10 to the inner wall of the element receiving recess 32.

(5) 従来のようにホルダのくぼみ部で磁気感応素子を位置決めする構成では、磁気感応素子１０の個数を増やしたり磁気感応素子１０間の距離（角度）を変更したりする場合に、それぞれ専用のケースを作製する必要がある。これに対し、本実施の形態では、素子収容凹部３２を大きくとったケース３０を用意しておけば、ケース３０はそのままで、専用には回路基板２０及び位置決め治具５０を用意すればよい。そのため、総合的な原価低減効果が得られる。 (5) In the conventional configuration in which the magnetic sensitive elements are positioned in the recessed portion of the holder, each is dedicated when the number of the magnetic sensitive elements 10 is increased or the distance (angle) between the magnetic sensitive elements 10 is changed. It is necessary to make a case. On the other hand, in the present embodiment, if a case 30 having a large element housing recess 32 is prepared, the case 30 may be left as it is, and the circuit board 20 and the positioning jig 50 may be prepared exclusively. Therefore, a comprehensive cost reduction effect can be obtained.

(6) 従来のようにホルダのくぼみ部で磁気感応素子を位置決めする構成では、センサの個体ごとにマイナス公差であったりプラス公差であったりするため、センサ出力の個体間バラツキが発生する。これに対し、本実施の形態では、回路基板２０に対する磁気感応素子１０の位置決めはケース３０に依存しないため、センサ出力の個体間バラツキを大幅に低減できる。また、位置決め治具５０を１つで運用すると、治具間のバラツキも無くなり、センサ出力の個体間バラツキを一層低減できる。 (6) In the conventional configuration in which the magnetically sensitive element is positioned at the recessed portion of the holder, there is a minus tolerance or a plus tolerance for each individual sensor, resulting in variations in sensor output among individuals. On the other hand, in the present embodiment, since the positioning of the magnetic sensitive element 10 with respect to the circuit board 20 does not depend on the case 30, sensor output variation among individuals can be greatly reduced. Further, when the single positioning jig 50 is operated, there is no variation between the jigs, and the variation in individual sensor output can be further reduced.

以上、実施の形態を例に本発明を説明したが、実施の形態の各構成要素や各処理プロセスには請求項に記載の範囲で種々の変形が可能であることは当業者に理解されるところである。以下、変形例について触れる。 The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.

位置決め治具５０の材質は、金属に限らず、樹脂よりも高精度の外形寸法で形成可能な樹脂以外の材質としてもよい。 The material of the positioning jig 50 is not limited to a metal, and may be a material other than a resin that can be formed with an external dimension with higher accuracy than a resin.

素子収容凹部３２は、複数の磁気感応素子１０を一括して収容する実施の形態で例示のタイプ（図６（Ｂ）参照）に限らず、磁気感応素子１０を一つずつ収容する個別穴タイプ（図６（Ａ）参照）であってもよい。個別穴タイプの場合も、素子収容凹部３２は磁気感応素子１０の位置を規制しない程度に十分大きいものとする。 The element accommodating recess 32 is not limited to the type illustrated in the embodiment for accommodating a plurality of magnetic sensitive elements 10 in a lump (see FIG. 6B), and is an individual hole type for accommodating the magnetic sensitive elements 10 one by one. (See FIG. 6A). Even in the case of the individual hole type, the element receiving recess 32 is sufficiently large so as not to regulate the position of the magnetic sensitive element 10.

実施の形態ではリング状マグネット等の回転体の回転角度を検出する角度センサを説明したが、位置検出の対象は回転体に限らず、所定ピッチで着磁された直線移動体等であってもよい。例えば直線移動体の場合、複数の磁気感応素子は直線移動体に対面するように一平面上に配置すればよい。 In the embodiment, the angle sensor that detects the rotation angle of the rotating body such as the ring magnet has been described. However, the position detection target is not limited to the rotating body, but may be a linear moving body or the like magnetized at a predetermined pitch. Good. For example, in the case of a linear moving body, the plurality of magnetically sensitive elements may be arranged on one plane so as to face the linear moving body.

磁気感応素子１０の個数は、３つに限らず、２つ又は４つ以上であってもよく、製品仕様や用途その他の要因に合わせて適宜決定すればよい。 The number of the magnetic sensitive elements 10 is not limited to three, but may be two or four or more, and may be appropriately determined according to product specifications, applications, and other factors.

磁気感応素子１０は、ホールＩＣに限らず、ＭＲ素子等であってもよい。 The magnetic sensitive element 10 is not limited to the Hall IC, but may be an MR element or the like.

１０磁気感応素子
１１本体部
１２リード端子
２０回路基板
２０ａ曲線状縁部
２１電極部
３０ケース
３１基板搭載面
３２素子収容凹部
５０位置決め治具
２０１位置決め穴
３０１ガイドピン DESCRIPTION OF SYMBOLS 10 Magnetic sensing element 11 Main-body part 12 Lead terminal 20 Circuit board 20a Curved edge part 21 Electrode part 30 Case 31 Board | substrate mounting surface 32 Element accommodation recessed part 50 Positioning jig 201 Positioning hole 301 Guide pin

Claims

各々がリード端子を有する複数の磁気感応素子と、前記複数の磁気感応素子に対して共通に設けられ各リード端子が接続固定された回路基板と、前記回路基板を位置決め保持するケースとを備え、
前記ケースは、前記回路基板を搭載する基板搭載面と、前記基板搭載面から凹む素子収容凹部とを有し、
前記複数の磁気感応素子は、相互に位置決めされた状態で各々のリード端子が前記回路基板に接続固定され、本体部が前記素子収容凹部内に位置し、
前記素子収容凹部が、前記複数の磁気感応素子の位置を規制しないことを特徴とする、位置センサ。 A plurality of magnetic sensitive elements each having a lead terminal; a circuit board provided in common to the plurality of magnetic sensitive elements to which each lead terminal is connected and fixed; and a case for positioning and holding the circuit board,
The case has a substrate mounting surface on which the circuit board is mounted, and an element receiving recess recessed from the substrate mounting surface,
Each of the plurality of magnetically sensitive elements is fixedly connected to the circuit board in a state where the plurality of magnetically sensitive elements are positioned with respect to each other, and a main body portion is located in the element receiving recess,
The element housing recess, wherein the go, such regulate the positions of the plurality of magnetically sensitive elements, the position sensor.

各々がリード端子を有する複数の磁気感応素子を回路基板に対して位置決め治具を用いて位置決めした状態を維持しながら、各リード端子を前記回路基板に接続固定する接続工程と、
前記接続工程の後に、前記複数の磁気感応素子及び前記回路基板をケースに収容する収容工程とを含む、位置センサ製造方法。 A connection step of connecting and fixing each lead terminal to the circuit board while maintaining a state in which a plurality of magnetic sensitive elements each having a lead terminal are positioned with respect to the circuit board using a positioning jig;
A position sensor manufacturing method including a housing step of housing the plurality of magnetically sensitive elements and the circuit board in a case after the connecting step.

請求項２に記載の方法において、前記位置決め治具は、
台部と、前記台部の縁から下方に延びる側壁と、前記側壁から凹み且つ３つの位置規制面を有し、上方が開放である複数の位置決め用凹部と、前記位置決め用凹部に対して相対移動可能なプッシャーとを有し、
前記接続工程では、前記回路基板を前記台部に搭載し、前記磁気感応素子の３つの側面を前記３つの位置規制面で支持しながら、前記磁気感応素子の側面のうち前記位置規制面の対面していない側面を前記プッシャーで前記位置決め用凹部に向けて押し付ける、位置センサ製造方法。 3. The method according to claim 2, wherein the positioning jig is
Relative to the positioning recess, the side wall extending downward from the edge of the base portion, the plurality of positioning recesses recessed from the side wall and having three position restricting surfaces, the upper part being open A movable pusher,
In the connecting step, the circuit board is mounted on the pedestal, and the three side surfaces of the magnetic sensitive element are supported by the three position restricting surfaces, and the position restricting surface of the side surfaces of the magnetic sensitive element faces each other. A method for manufacturing a position sensor, wherein a side surface that is not pressed is pressed against the positioning recess by the pusher.

請求項２又は３に記載の方法において、
前記ケースは、基板搭載面と、前記基板搭載面から凹む素子収容凹部とを有し、
前記素子収容凹部は、前記複数の磁気感応素子の位置を規制しない程度に十分大きく、
前記収容工程では、前記回路基板を前記基板搭載面上に位置決めし、かつ前記複数の磁気感応素子の本体部を前記素子収容凹部内に位置させる、位置センサ製造方法。 The method according to claim 2 or 3,
The case has a substrate mounting surface and an element receiving recess recessed from the substrate mounting surface,
The element accommodating recess is sufficiently large so as not to regulate the positions of the plurality of magnetically sensitive elements,
In the housing step, the circuit board is positioned on the substrate mounting surface, and the main body portions of the plurality of magnetically sensitive elements are positioned in the element housing recesses.

請求項４に記載の方法において、前記収容工程では、前記基板搭載面から突出したガイドピンを前記回路基板の位置決め穴に通し、前記回路基板を前記基板搭載面上に位置決め固定する、位置センサ製造方法。 5. The method according to claim 4, wherein, in the accommodating step, a guide pin protruding from the board mounting surface is passed through a positioning hole of the circuit board, and the circuit board is positioned and fixed on the board mounting surface. Method.

請求項２から５のいずれかに記載の方法において、各リード端子を所定位置で折り曲げて先端側に折曲げ部を形成しておき、前記接続工程では前記折曲げ部を前記回路基板に接続固定する、位置センサ製造方法。 6. The method according to claim 2, wherein each lead terminal is bent at a predetermined position to form a bent portion on a tip end side, and the bent portion is connected and fixed to the circuit board in the connecting step. A position sensor manufacturing method.

請求項２から６のいずれかに記載の方法において、前記収容工程の後に、前記ケース内を絶縁樹脂で封止することを特徴とする、位置センサ製造方法。 The method according to claim 2, wherein the inside of the case is sealed with an insulating resin after the housing step.

各々がリード端子を有する複数の磁気感応素子を回路基板に対して位置決め可能な位置決め治具であって、
回路基板を搭載する台部と、
前記台部の縁から下方に延びる側壁と、
前記側壁から凹み、磁気感応素子の３つの側面に当接する位置規制面を有し、上方が開放である複数の位置決め用凹部と、
前記位置決め用凹部に位置する磁気感応素子の側面のうち前記位置規制面の対面していない側面を前記位置決め用凹部に向けて押付け可能に前記位置決め用凹部に対して相対移動するプッシャーとを備える、位置決め治具。 A positioning jig capable of positioning a plurality of magnetically sensitive elements each having a lead terminal with respect to a circuit board,
A base for mounting a circuit board;
A side wall extending downward from an edge of the platform;
A plurality of positioning recesses that are recessed from the side wall, have position restricting surfaces that abut against the three side surfaces of the magnetically sensitive element, and are open at the top;
A pusher that moves relative to the positioning recess so as to be able to press the side surface of the magnetically sensitive element positioned in the positioning recess that is not facing the position regulating surface toward the positioning recess; Positioning jig.

請求項８に記載の位置決め治具において、樹脂よりも高精度の外形寸法で形成可能な樹脂以外の材質であることを特徴とする、位置決め治具。 9. The positioning jig according to claim 8, wherein the positioning jig is made of a material other than resin that can be formed with an outer dimension with higher accuracy than resin.