JP2007318825A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus capable of preventing a foreign matter or humidity from entering into a casing from a through hole by reducing an unwanted clearance between a terminal and the through hole of the casing as much as possible. <P>SOLUTION: The through hole 8C to which the terminal 9 having a square cross section is inserted consists of four line segments a<SB>2</SB>, b<SB>2</SB>, c<SB>2</SB>, d<SB>2</SB>and four connection lines A<SB>4</SB>, B<SB>4</SB>, C<SB>4</SB>, D<SB>4</SB>for connecting the line segments a<SB>2</SB>, b<SB>2</SB>, c<SB>2</SB>, d<SB>2</SB>. Clearances each having a maximum permissible dimension m of variation in assembly between the terminal 9 and the through hole 8C are respectively formed between each of the line segments a<SB>2</SB>, b<SB>2</SB>, c<SB>2</SB>, d<SB>2</SB>and each of sides a<SB>1</SB>, b<SB>1</SB>, c<SB>1</SB>, d<SB>1</SB>of the cross sectional shape of the polygon of the terminal 9. Also, the connection lines A<SB>4</SB>, B<SB>4</SB>, C<SB>4</SB>, D<SB>4</SB>each form an arc constituting a circle T centered at each of apices A<SB>1</SB>, B<SB>1</SB>, C<SB>1</SB>, D<SB>1</SB>of the cross sectional shape of the terminal 9, where the maximum permissible dimension m of the variation in assembly is a radius. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic device in which a terminal of an electronic component housed in a housing is exposed to the outside through a through hole provided in the housing, and in particular, an analog pointer is rotated in a vehicle instrument device It relates to a stepping motor.

  Conventionally, stepping motors as electronic devices have been used as actuator parts in the fields of various OA devices, home appliances, automobiles, and the like. For example, a vehicle instrument device that displays measured values such as a vehicle speed and an engine speed is mounted on the vehicle, and in this vehicle instrument device, an internal unit that drives an analog pointer disposed on the front face of a dial This stepping motor is used.

  The stepping motor (see Patent Document 1) includes a case as a housing, an output shaft that protrudes from the case and attaches the pointer and the like, a rotor having a magnet rotatably supported in the case, A plurality of gears for transmitting the rotational force of the rotor to the output shaft; and a stator fixed in the case. This stator has a plurality of coils as electronic components and a frame to which the coils are attached. The coil includes a bobbin, a lead wire wound around the outer periphery of the bobbin, and a pair of terminals formed in a rod shape. This terminal is exposed to the outside of the case through a through hole provided in the case, and is connected to a circuit board disposed on the back side of the dial.

The stepping motor having the above-described configuration generates a magnetic flux by exciting a coil with an excitation signal sent from a circuit board to a lead wire through a terminal. The rotor and the output shaft are rotated by the magnetic flux to rotate the pointer.
JP 2001-320866 A

The conventional stepping motor having the above-described configuration has a clearance between the through hole 100 and the terminal 1 as shown in FIG. This clearance is provided in consideration of absorption of the assembly variation between the terminal 1 and the through hole 100 (case). The terminal 1 shown in FIG. 6 is formed in a square shape having a cross-sectional shape having four vertices A ₁ , B ₁ , C ₁ , D ₁ and four sides a ₁ , b ₁ , c ₁ , d _1. ing. In addition, the through hole 100 has a planar shape of the sum r ₁ of the dimension l from the center P of the terminal 1 to any vertex A ₁ , B ₁ , C ₁ , D ₁ and the maximum allowable dimension m of the assembly variation. It is formed in a circle with a radius.

  However, the conventional stepping motor shown in FIG. 6 has a problem that foreign matter such as floating dust and moisture due to condensation easily enter the case from the clearance. In particular, the floating dust that has entered the case has caused the above-described rotation of the gear and causes a malfunction of the stepping motor.

  That is, the clearance is necessary for absorbing the assembly variation between the terminal 1 and the through hole 100 (case) as described above. However, as described above, the viewpoint of preventing foreign matter from entering the case. Then, it is preferable that the unnecessary clearance is as small as possible.

As a solution to the above problem, as shown in FIG. 7, a stepping motor in which the planar shape of the through hole 101 is similar to the cross-sectional shape of the terminal 1 is disclosed in Japanese Patent Laid-Open No. 2005-24501. In such a stepping motor, for example, between the sides a ₁ , b ₁ , c ₁ , and d _{1 of} the terminal 1 and the inner surfaces a ₁₀ , b ₁₀ , c ₁₀ , and d ₁₀ of the through-hole 101 facing each other. Is set to the maximum permissible dimension m of the assembly variation between the terminal 1 and the through hole 101 (case), so that the unnecessary clearance as compared with the stepping motor having the through hole 100 having a circular planar shape shown in FIG. Can be reduced. However, even in this case, as shown in the figure, the vertices A ₁ , B ₁ , C ₁ , D ₁ of the terminal 1 and the vertices A ₁₀ , B ₁₀ , C ₁₀ , D _{10 of the} through-hole 101 are used. Since there is a clearance of √2 × m, there is an unnecessary clearance.

  Therefore, the present invention provides an electronic device that can reduce the intrusion of foreign matter and moisture from the through hole into the housing by minimizing unnecessary clearance between the terminal and the through hole of the housing. For the purpose.

  In order to achieve the above-described object, according to the first aspect of the present invention, the terminal of the electronic component housed in the housing is exposed to the outside through the through hole provided in the housing. In the electronic device, the terminal is formed in a bar shape having a polygonal cross-section, and the planar shape of the through hole has each side of the polygon in the cross-sectional shape of the terminal at the center of the polygon. On the other hand, it is an electronic device characterized by having a shape constituted by each line segment translated parallel to the outside and a connection line connecting the line segments.

  The invention described in claim 2 is the invention described in claim 1, wherein the connection line has a dimension from the center of a polygon of the cross-sectional shape of the terminal to an arbitrary vertex, the terminal, and the through hole. The arc is centered on the center of the polygon of the cross-sectional shape of the terminal, with the radius being the sum of the maximum permissible dimensions of the assembly variation.

  The invention described in claim 3 is the invention described in claim 1, wherein the connection line has a dimension from the center of a polygon of a cross-sectional shape of the terminal to an arbitrary vertex, the terminal, and the through hole. A straight line that is at least partially arranged on a circumference centered on the center of the polygon of the cross-sectional shape of the terminal, with the radius being the sum of the maximum allowable dimension of the assembly variation of the terminal It is.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, each of the line segments may be arranged such that each side of a polygon having a cross-sectional shape of the terminal is connected to the terminal with respect to the center of the polygon. The maximum allowable dimension of the assembly variation with the through hole is a line segment translated outward, and the connection line is centered on each vertex of the cross-sectional shape of the terminal with the maximum allowable dimension as a radius. It is characterized by a circular arc.

  According to the invention described in claim 1, the through hole is constituted by each line segment obtained by translating each side of the polygon of the cross-sectional shape of the terminal to the outside with respect to the center of the polygon. Therefore, an unnecessary clearance between the terminal and the through hole can be reduced as compared with the case where the through hole is formed in a circular shape. In addition, by connecting these line segments with connecting lines, unnecessary clearance between each apex of the terminal and the through hole can be obtained compared to the case where the through hole is formed in a polygon having a cross-sectional shape similar to that of the terminal. Can be reduced. Therefore, it is possible to provide an electronic device that can reduce the intrusion of foreign matter and moisture from the through hole into the housing.

  According to the invention described in claim 2, each line segment is the sum of the dimension from the center of the polygon of the cross-sectional shape of the terminal to an arbitrary vertex and the maximum allowable dimension of the assembly variation of the terminal and the through hole. By connecting arcs around the center of the polygon of the cross-sectional shape of the terminal and the through hole in a polygon having a shape similar to the cross-sectional shape of the terminal, Unnecessary clearance between the through hole can be reduced. Therefore, it is possible to provide an electronic device that can reduce the intrusion of foreign matter and moisture from the through hole into the housing.

  Further, the die pin for forming the through hole has a radius that is the sum of the dimension from the center of the polygon of the cross-sectional shape of the terminal to an arbitrary vertex and the maximum allowable dimension of the assembly variation between the terminal and the through hole. Using the round pin, the portion corresponding to the line segment of the round pin can be ground at a low cost.

  According to the invention described in claim 3, each of the line segments is the sum of the dimension from the center of the polygon of the cross-sectional shape of the terminal to an arbitrary vertex and the maximum allowable dimension of the assembly variation between the terminal and the through hole. The through hole is formed into a polygon that is similar to the cross-sectional shape of the terminal by connecting at least a part of the straight line on the circumference centered on the center of the polygon of the cross-sectional shape of the terminal Compared with the case where it does, the unnecessary clearance between each vertex of a terminal and a through-hole can be decreased. Therefore, it is possible to provide an electronic device that can reduce the intrusion of foreign matter and moisture from the through hole into the housing.

  In addition, the mold pin for forming the through hole is a square pin whose cross-sectional shape is similar to the cross-sectional shape of the terminal, and the portion corresponding to the connecting line of the square pin is an arc shape. It can be made inexpensively by grinding.

  According to the invention described in claim 4, the maximum permissible dimension of the assembling variation between the terminal and the through hole with respect to each side of the polygon of the cross-sectional shape of the terminal with respect to the center of the polygon. Since it is constituted by the respective line segments that are translated parallel to the outside, unnecessary clearance between the terminal and the through hole can be eliminated. Further, by connecting each of these line segments with an arc centered on each vertex of the cross-sectional shape of the terminal with the maximum allowable dimension as a radius, unnecessary clearance between each vertex of the terminal and the through hole can be eliminated. it can. Therefore, it is possible to provide an electronic device that can reduce the intrusion of foreign matter and moisture from the through hole into the housing.

  In addition, the mold pin for forming the through hole is a square pin whose cross-sectional shape is similar to the cross-sectional shape of the terminal, and the portion corresponding to the connecting line of the square pin is an arc shape. It can be made inexpensively by grinding.

  Hereinafter, an electronic apparatus according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. The “electronic device” of the present embodiment is a stepping motor 2 as an internal unit that drives an analog pointer disposed on the front face of a dial of a vehicle instrument device.

  As shown in FIG. 1, the stepping motor 2 includes a case 3 as a housing, an output shaft 4 that protrudes from the case 3 and attaches the pointer and the like, and a rotor that has a magnet rotatably supported in the case 3. 5, a plurality of gears 6 a, 6 b, 6 c, 6 d that transmit the rotational force of the rotor 5 to the output shaft 4, a stator 7 fixed in the case 3, and the like.

  The case 3 is made of an insulating synthetic resin and has an upper case 3a and a lower case 3b that can be connected to each other. The case 3 is formed into a flat box shape by connecting the upper case 3a and the lower case 3b to each other. The case 3 accommodates the output shaft 4, the rotor 5, the plurality of gears 6a, 6b, 6c, 6d, the stator 7, and the like described above. Moreover, 8A in FIG. 1 is a through hole through which a terminal 9 of a coil 7a described later is passed. The through hole 8A will be described later.

  The stator 7 has a frame 7b and a plurality of coils 7a as electronic components. The frame 7b is fixed to the case 3 by attaching an end portion of the frame 7b between the upper case 3a and the lower case 3b after the coil 7a is attached.

  The coil 7a has a synthetic resin bobbin, a lead wire wound around the outer periphery of the bobbin, and a pair of terminals 9 supported by the bobbin and formed in a prismatic shape. One end of the terminal 9 is positioned outside the case 3 through a through-hole 8A (described later) provided in the lower case 3b, and is connected to the circuit board 10 disposed on the back side of the dial.

  The stepping motor 2 having the above-described configuration generates a magnetic flux by exciting the coil 7a with an excitation signal sent from the circuit board 10 to the lead wire through the terminal 9. Then, the rotor 5 and the output shaft 4 are rotated by the magnetic flux to rotate the pointer.

  Subsequently, the shapes of the terminal 9 and the through hole 8A described above will be described in detail.

As shown in FIG. 2, the terminal 9 is formed in a square shape having four vertices A ₁ , B ₁ , C ₁ , D ₁ and four sides a ₁ , b ₁ , c ₁ , d _1. Has been.

The through hole 8A is provided on the lower case 3b side. The through-hole 8A is a four line segments _{a 2, b 2, c 2} , d 2, each line segment _{a 2, b 2, c 2} , 4 one connection line connecting the _{d 2 A 2, B 2,} C ₂ and D ₂ . The line segments a ₂ , b ₂ , c ₂ , and d ₂ are obtained by making the respective sides a ₁ , b ₁ , c ₁ , and d ₁ of the polygon of the cross-sectional shape of the terminal 9 with respect to the center P of the polygon. This is a line segment translated outward. The connection lines A ₂ , B ₂ , C ₂ , and D ₂ have dimensions l from the polygonal center P of the cross-sectional shape of the terminal 9 to any vertex A ₁ , B ₁ , C ₁ , D ₁ and the terminal. 9 is a circular arc that forms a circle S centered on the center P of the polygon of the cross-sectional shape of the terminal 9 with the radius r ₁ as the sum of the maximum allowable dimension m of the assembly variation of 9 and the through hole 8A.

According to the terminal 9 and the through hole 8A having such a configuration, an assembly variation between the terminal 9 and the through hole 8A (lower case 3b) is considered between the outer surface of the terminal 9 and the inner surface of the through hole 8A. Since the clearance is set, the assembly variation can be absorbed. Further, the through-hole 8A is a line segment obtained by translating each side a ₁ , b ₁ , c ₁ , d ₁ of the polygon of the cross-sectional shape of the terminal 9 to the outside with respect to the center P of the polygon. Since it is composed of a ₂ , b ₂ , c ₂ , and d ₂ , unnecessary clearance between the terminal 9 and the through hole 8A can be reduced as compared with the case where the through hole 8A is formed in a circular shape. it can. Further, each line segment a ₂ , b ₂ , c ₂ , d ₂ is divided into a dimension l from the center P of the polygonal shape of the cross section of the terminal 9 to any vertex A ₁ , B ₁ , C ₁ , D ₁ and the terminal 9. Connecting arcs A ₂ , B ₂ , C centered on the center P of the polygonal shape of the cross-sectional shape of the terminal 9 with the radius r ₁ as the sum of the maximum allowable dimension m of the assembly variation of the through hole 8A and the through hole 8A ₂ and D ₂ , the vertices A ₁ , B ₁ , C ₁ , D _{1 of} the terminal 9 are compared with the case where the through-hole 8A is formed in a polygon having a shape similar to the cross-sectional shape of the terminal 9. Unnecessary clearance with the through hole 8A can be reduced. Accordingly, it is possible to reduce the entry of foreign matter and moisture into the case 3 from the through hole 8A.

  Next, a stepping motor 2 according to a second embodiment of the present invention will be described with reference to FIG. In the figure, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

The stepping motor 2 of the present embodiment has a through hole 8B shown in FIG. The through hole 8B is provided on the lower case 3b side. The through holes 8B, the four line segments _{a 2, b 2, c 2} , d 2 and, each line segment _{a 2, b 2, c 2} , connects the d ₂ four connection lines A _3, B _3, C It is composed of _3, D _3. The connection lines A ₃ , B ₃ , C ₃ , and D ₃ are straight lines having both ends arranged on the circumference of the circle S described above. The clearances between the connection lines A ₃ , B ₃ , C ₃ , D ₃ and the vertices A ₁ , B ₁ , C ₁ , D ₁ of the terminal 9 are the variations in the assembly between the terminal 9 and the through hole 8B. Although the dimension is slightly smaller than the maximum allowable dimension m, the dimension does not affect the assembly of the terminal 9 and the through hole 8B (lower case 3b).

According to the terminal 9 and the through hole 8B having such a configuration, an assembly variation between the terminal 9 and the through hole 8B (lower case 3b) is considered between the outer surface of the terminal 9 and the inner surface of the through hole 8B. Since the clearance is set, the assembly variation can be absorbed. Further, the through-hole 8B is a line segment obtained by translating the polygonal sides a ₁ , b ₁ , c ₁ , and d ₁ of the terminal 9 to the outside with respect to the center P of the polygon. Since it is composed of a ₂ , b ₂ , c ₂ , and d ₂ , unnecessary clearance between the terminal 9 and the through hole 8B can be reduced as compared with the case where the through hole 8B is formed in a circular shape. it can. Further, each line segment a ₂ , b ₂ , c ₂ , d ₂ is divided into a dimension l from the center P of the polygonal shape of the cross section of the terminal 9 to any vertex A ₁ , B ₁ , C ₁ , D ₁ and the terminal 9. Both ends are arranged on the circumference of a circle S centered on the center P of the polygon of the cross-sectional shape of the terminal 9 with the radius r ₁ of the maximum permissible dimension m of the assembly variation between the contact hole 8B and the through hole 8B. By connecting the connecting holes A ₃ , B ₃ , C ₃ , and D ₃ with each other, the through-hole 8B is formed in a polygon having a shape similar to the cross-sectional shape of the terminal 9, and each terminal 9 Unnecessary clearances between the apexes A ₁ , B ₁ , C ₁ , D ₁ and the through hole 8B can be reduced. Accordingly, it is possible to reduce the entry of foreign matter and moisture into the case 3 from the through hole 8B.

  Next, a modification of the stepping motor 2 according to the second embodiment will be described with reference to FIG. In the figure, the same components as those in the first and second embodiments described above are denoted by the same reference numerals and description thereof is omitted.

The stepping motor 2 of the present embodiment has a through hole 8B ′ shown in FIG. The through hole 8B ′ is provided on the lower case 3b side. The through hole 8B 'is a four line segments _{a 2, b 2, c 2} , d 2, each line segment _{a 2, b 2, c 2} , connects the d ₂ four connection lines A _3', B ₃ ', C ₃ ', D ₃ '. The connection lines A ₃ ′, B ₃ ′, C ₃ ′, and D ₃ ′ are straight lines in which one point at the center is circumscribed on the circumference of the circle S described above. Thus, in the present invention, the connection line may be a straight line that is at least partially arranged on the circumference of the circle S.

  Next, a stepping motor 2 according to a third embodiment of the present invention will be described with reference to FIG. In the figure, the same components as those of the first and second embodiments and the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

The stepping motor 2 of the present embodiment has a through hole 8C shown in FIG. The through hole 8C is provided on the lower case 3b side. Further, through holes 8C includes four line segments _{a 2, b 2, c 2} , d 2, each line segment _{a 2, b 2, c 2} , 4 one connection line connecting the d ₂ A _4, B _4, C It is composed of _4, D _4. Between the line segments a ₂ , b ₂ , c ₂ , and d ₂ and the polygonal sides a ₁ , b ₁ , c ₁ , and d ₁ of the terminal 9, the terminal 9 and the through hole 8 C ( The clearance of the maximum permissible dimension m of the assembly variation with the lower case 3b) is set.

The connection lines A ₄ , B ₄ , C ₄ , and D ₄ are the vertices A ₁ , B ₁ , C ₁ , D ₁ of the cross-sectional shape of the terminal 9 with the maximum allowable dimension m of the assembly variation as the radius. Is a circular arc that forms a circle T centered at.

According to the terminal 9 and the through hole 8C having such a configuration, an assembly variation between the terminal 9 and the through hole 8C (lower case 3b) is considered between the outer surface of the terminal 9 and the inner surface of the through hole 8C. Since the clearance is set, the assembly variation can be absorbed. Further, the through-hole 8C is configured such that the polygonal sides a ₁ , b ₁ , c ₁ , and d ₁ of the cross-sectional shape of the terminal 9 are the maximum allowable dimension of the assembly variation with respect to the center P of the polygon. Since it is composed of the line segments a ₂ , b ₂ , c ₂ , and d ₂ that have been translated m outside, unnecessary clearance between the terminal 9 and the through hole 8C can be eliminated. Further, each line segment a ₂ , b ₂ , c ₂ , d ₂ is defined as a radius of the maximum allowable dimension m of the assembly variation and each vertex A ₁ , B ₁ , C ₁ , D ₁ of the cross-sectional shape of the terminal 9 is By connecting arc-shaped connecting lines A ₄ , B ₄ , C ₄ , and D ₄ that form a center circle T, each vertex A ₁ , B ₁ , C ₁ , D ₁ of the terminal 9 and the through hole 8C Unnecessary clearance between the two can be eliminated. Accordingly, it is possible to reduce the entry of foreign matter and moisture into the case 3 from the through hole 8C.

  In the first to third embodiments, the terminal 9 having a square cross-sectional shape is described as an example. However, in the present invention, the cross-sectional shape may be a regular polygon other than a square.

  In the first to third embodiments, the stepping motor 2 is used as the electronic device. However, the electronic device of the present invention is not limited to the stepping motor 2, and a case provided with a through hole and the case accommodated in the case. Any electronic device may be used as long as the electronic device includes an electronic component having a terminal that is passed through the through hole.

  Note that “upper” and “lower” of the upper case 3a and the lower case 3b used in the present specification are expressions for convenience of description of the present specification, and their actual vertical directions are reversed. It does not matter if

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

1 is a cross-sectional view showing a stepping motor according to a first embodiment of the present invention. It is explanatory drawing for demonstrating the shape of the terminal and through-hole of the stepping motor shown by FIG. It is explanatory drawing for demonstrating the shape of the terminal and through-hole of a stepping motor which concerns on the 2nd Embodiment of this invention. It is explanatory drawing for demonstrating the shape of the terminal and through-hole of the modification of the stepping motor which concerns on the 2nd Embodiment of this invention. It is explanatory drawing for demonstrating the shape of the terminal and through-hole of a stepping motor which concerns on the 3rd Embodiment of this invention. It is explanatory drawing for demonstrating the shape of the terminal and through-hole of the conventional stepping motor. It is explanatory drawing for demonstrating the shape of the terminal and through-hole of the other conventional stepping motor.

Explanation of symbols

2 Stepping motor (electronic equipment)
3 Case (housing)
7a Coil (electronic component)
8A, 8B, 8B ', 8C through hole 9 terminals _{A 1, B 1, C 1} , D 1 vertex _{A 2, B 2, C 2} , D 2 connected line _{A 3, B 3, C 3} , D 3 connection lines A ₃ ', B ₃ ', C ₃ ', D ₃ ' connecting lines A ₄ , B ₄ , C ₄ , D ₄ connecting lines a ₁ , b ₁ , c ₁ , d ₁ sides a ₂ , b ₂ , c ₂ , D ₂ line segment P polygon center

Claims (4)

An electronic device in which a terminal of an electronic component housed in the housing is exposed outside the housing through a through hole provided in the housing,
The terminal is formed in a rod shape having a polygonal cross-section, and
The planar shape of the through hole is
Each line segment obtained by translating each side of the polygon of the cross-sectional shape of the terminal to the outside with respect to the center of the polygon;
A connection line connecting the line segments;
An electronic device characterized by having a shape constituted by   The connection line has a cross-sectional shape of the terminal, the radius of which is the sum of the dimension from the center of the polygon of the cross-sectional shape of the terminal to an arbitrary vertex and the maximum allowable dimension of assembly of the terminal and the through hole. The electronic apparatus according to claim 1, wherein the electronic apparatus is an arc centered on the center of the polygon.   The connection line has a cross-sectional shape of the terminal, the radius of which is the sum of the dimension from the center of the polygon of the cross-sectional shape of the terminal to an arbitrary vertex and the maximum allowable dimension of assembly of the terminal and the through hole. The electronic device according to claim 1, wherein the electronic device is a straight line at least a part of which is arranged on a circumference centered on the center of the polygon. Each line segment is a line obtained by translating each side of the polygon of the cross-sectional shape of the terminal to the outside of the maximum allowable dimension of the assembly variation between the terminal and the through hole with respect to the center of the polygon. Minutes, and
2. The electronic device according to claim 1, wherein the connection line is an arc centered at each vertex of a cross-sectional shape of the terminal with the maximum allowable dimension as a radius.

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