JP2005032806A - Spiral flexible printed wiring board and meter using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spiral flexible printed wiring board which prevents step-out of a stepping motor and can make exact direction perform, and to provide a meter using it. <P>SOLUTION: The central part 120 of a wiring board where an electrode 12a to be connected electrically with a guide side is fixed to a base end portion 141 of the guide and rotates integrally with the guide. Two wiring board swirl parts 121, 122 are formed which become spirals of mutually inverse winding directions from the central part 120 toward the outside. In a part of each of the two wiring board swirl parts 121, 122, mounting members 121a, 122b are formed which are fixed to a predetermined part positions of a stepping motor 10 side. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spiral flexible printed wiring board and a meter using the same, and more particularly to a rotational torque of a stepping motor that functions as a lead wire for supplying power to a light emitting element mounted on a pointer and rotates the pointer. The present invention relates to a spiral flexible printed wiring board having a spring property to balance the pointer at a predetermined designated position and an instrument using the spiral flexible printed wiring board.
[0002]
[Prior art]
Conventionally, this kind of spiral flexible printed wiring board (hereinafter, the flexible printed wiring board is simply referred to as FPC) and an instrument using the same are disclosed in Patent Document 1 below, for example. The spiral FPC described in Patent Document 1 is integrally formed with a pointer indicating unit on which a plurality of light emitting diodes (LEDs) are mounted, and is wound in a left-handed spiral around the outer periphery of the pointer shaft. . The spiral FPC functions as a lead wire for supplying power to the LED and has a spring property for generating a braking torque with respect to the driving torque of the motor.
[0003]
In such a configuration, the motor is driven in response to a predetermined drive signal from the instrument control board (not shown), and the angle of the pointer is stabilized at the balance point between the torque generated by this drive and the braking force of the spiral FPC. A predetermined instruction is given. At the same time, power is supplied from a power supply circuit (not shown) to a predetermined LED mounted on the pointer via a spiral FPC, and the pointer is illuminated when the LED is turned on.
[0004]
[Patent Document 1]
Japanese Examined Patent Publication No. 6-66601 (FIG. 3)
[0005]
[Problems to be solved by the invention]
However, in the conventional spiral FPC as described above, the spiral conductive portion is wound only in one direction. As described above, when the entire ribbon-shaped FPC is wound only in one direction, the spring property, that is, the Young's modulus of the spiral conductive part tends to increase. For this reason, the load on the stepping motor is increased, and step-out occurs and the indicated value is likely to be incorrect. In order to reduce the spring property of the spiral conductive portion, the width of the spiral FPC may be reduced. However, the spiral FPC also functions as a lead wire for independently supplying power to a plurality of LEDs. , Can not be thinned easily.
[0006]
Therefore, in view of the present situation described above, the present invention has a spiral shape that makes it possible to reduce the spring property while preventing the stepping motor from stepping out while maintaining the full width of the printed wiring board and to give an accurate instruction. It is an object to provide a flexible printed wiring board and an instrument using the same.
[0007]
[Means for Solving the Problems]
The spiral flexible printed wiring board according to claim 1, which has been made to solve the above problem, functions as a lead wire for supplying power to a light emitting element mounted on a pointer rotating around a pointer shaft, A spiral flexible printed wiring board having a spring property to balance the rotational torque of a stepping motor that rotates the pointer and to stop the pointer at a predetermined designated position, to which a proximal end portion of the pointer is attached The wiring board central portion on which the electrode electrically connected to the pointer side is formed and the winding directions opposite to each other from the central portion of the wiring board to the outside. Two wiring board spiral parts formed in a spiral shape, and a fixed part that is a part of each of the two wiring board spiral parts and is fixed to a predetermined part on the stepping motor side. Special To.
[0008]
According to the first aspect of the present invention, the central portion of the wiring board on which the electrode electrically connected to the pointer side is formed is attached to the base end portion of the pointer and rotates integrally with the pointer. Two wiring board spirals having a spiral shape in opposite winding directions are formed from the center of the wiring board toward the outside. In addition, a fixed portion that is fixed to a predetermined portion on the stepping motor side is formed in a part of each of the two wiring board spiral portions. The two wiring board spirals in the winding directions opposite to each other can reduce the spring property in both directions while maintaining the full width of the printed wiring board.
[0009]
The spiral flexible printed wiring board according to claim 2, which has been made to solve the above-mentioned problems, is the spiral flexible printed wiring board according to claim 1, wherein the two wiring board spiral portions are one piece. The ribbon-shaped flexible printed wiring board is bifurcated, one is spirally wound in the right-handed direction, and the other is spirally wound in the left-handed direction.
[0010]
According to the second aspect of the present invention, since the two wiring board spiral portions are formed by bifurcating one ribbon-like flexible printed wiring board, manufacturing is easy.
[0011]
The spiral flexible printed wiring board according to claim 3, wherein the spiral flexible printed wiring board according to claim 2, wherein the central portion of the wiring board is the one piece. The vicinity of the end of the ribbon-like flexible printed wiring board is formed in a substantially cylindrical shape, and the electrode corresponding to the light emitting element is formed on the inner surface of the central part of the wiring board. It is characterized by that.
[0012]
According to the third aspect of the present invention, since the central portion of the wiring board to which the pointer is attached is also formed from a single ribbon-like flexible printed wiring board, manufacturing is easy. In addition, since the electrode is formed on the inner side surface of the central portion of the wiring board, electrical connection with the pointer side is easy.
[0013]
The instrument according to claim 4 made to solve the above-mentioned problem is an instrument using the spiral flexible printed wiring board according to any one of claims 1 to 3, wherein The fixing portion is fixed to a predetermined portion on the stepping motor side, and a light emitting element is mounted and rotated around a pointer shaft, and a base end portion of which is attached to the central portion of the wiring board, and the light emitting element It has an electrical connection member which electrically connects an element and the spiral flexible printed wiring board, and a cylindrical holder part which houses the central part of the wiring board.
[0014]
According to the fourth aspect of the present invention, the spiral flexible printed wiring board having the two wiring board spirals as described above is fixed to a predetermined portion on the stepping motor side, and the pointer is provided at the center of the wiring board. By attaching, a stepping motor can be prevented from being stepped out and an instrument capable of giving an accurate instruction can be provided. Further, since the holding torque of the motor can be reduced, a small stepping motor can be applied.
[0015]
The meter according to claim 5, which is made to solve the above problem, is the meter according to claim 4, wherein the electrical connection member is attached to a proximal end portion of the pointer so as to extend downward, and the light emitting element And a connection pin that contacts the electrode by utilizing an outward spring property.
[0016]
According to the fifth aspect of the present invention, the electrical connection between the pointer side and the spiral flexible printed wiring board side is achieved by the connecting pin attached to the base end portion of the pointer so as to extend downward and having a spring property toward the outside. Connection is easy and reliable.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view showing a part of an instrument using the spiral flexible printed wiring board of the present invention. FIG. 2 is a perspective view showing a state before the spiral flexible printed wiring board of FIG. 1 is wound. FIG. 3 is a front view of the spiral flexible printed wiring board of FIG. In FIG. 1, only members according to the gist of the present invention are shown, and a dial plate, a light guide, a printed board on which electronic parts are mounted, a pointer cover, a case, and the like are omitted.
[0018]
The spiral FPC 12 is a flexible printed wiring board in the form of a ribbon, and is used for an instrument 1 such as a speedometer as shown in FIG. The spiral FPC 12 forms a conductive pattern such as a copper foil on a resin base film, and ends of the electrode 12a formed on the inner surface of the wiring board central portion 120 and the two wiring board spiral portions 121 and 122. Except for the electrode patterns (not shown) formed on the fixing parts 121a and 122a, the insulating film is integrally formed on the insulating film. The spiral FPC 12 functions as a lead wire for supplying power to the light emitting element mounted on the pointer, and balances the rotational torque of the stepping motor 10 that rotates the pointer to stop the pointer at a predetermined indication position. Has springiness. The material itself of the spiral FPC 12 is well known.
[0019]
As shown in FIGS. 1 to 3, the spiral FPC 12 has an outer shape in which a base end portion 141 of the pointer hardware base 14 is attached and rotates integrally with the pointer, and is electrically connected to the pointer side. The wiring board central portion 120 on which the electrode 12a is formed, and two spiral springs that are formed in a spiral shape so as to have opposite winding directions outward from the wiring board central portion 120. The wiring board spiral parts 121 and 122 and the fixing parts 121a and 122a that are fixed to predetermined portions on the stepping motor side, which are the front ends of the two wiring board spiral parts 121 and 122, respectively.
[0020]
Supplementally, the two wiring board spiral portions 121 and 122 are formed by bifurcating one ribbon-like FPC, one spiraling in the right-handed direction, and the other spiraling in the left-handed direction. . The wiring board central portion 120 is also formed by winding the vicinity of the end portion of one ribbon-like FPC (the side not bifurcated) into a substantially cylindrical shape. As described above, the spiral FPC 12 is formed by bifurcating a part of one ribbon-like FPC, so that it can be easily manufactured and cost reduction can be promoted.
[0021]
A plurality of electrodes 12 a corresponding to a plurality of light emitting elements mounted on the pointer are formed on the inner side surface of the wiring board central portion 120. Each of the plurality of electrodes 12a is electrically connected to an electrode pattern (not shown) formed on the fixing portions 121a and 122a via two wiring board spiral portions 121 and 122 that function as lead wires.
[0022]
The wiring board central portion 120 is accommodated in a cylindrical electrode holder 11 (corresponding to the holder portion in the claims) having an inner diameter slightly larger than the outer diameter of the central portion 120. The electrode holder 11 is made of, for example, resin, and includes a slit 111 into which the vicinity of the branch portion of the two wiring board spiral portions 121 and 122 is inserted. In the spiral FPC 12 in which the electrode holder 11 is attached to the wiring board central part 120, the fixing parts 121a and 122a at the front ends of the two wiring board spiral parts 121 and 122 are electrically connected to the front surface of the printed board (not shown). Fixed mechanically. Electronic components related to this instrument are mounted on the printed circuit board.
[0023]
The stepping motor 10 is a known device that rotates the rotating shaft 102 by a predetermined angle in response to a drive signal generated according to the vehicle speed, for example, transmitted from an instrument control unit mounted on a printed board. is there. Supplementally, the drive signal is composed of a plurality of drive steps, and the rotating shaft 102 of the stepping motor 10 rotates in accordance with each drive step. While the stepping motor 10 can perform high-precision pointer control, it has a characteristic that so-called out-of-step is likely to occur, in which the synchronization between each drive step and the rotation angle of the rotary shaft 102 is out of the normal state. The stepping motor 10 has a locking claw 101 used when being fixed to the printed board or the instrument housing. Here, it is assumed that the stepping motor 10 is attached to the back surface of the printed board using the locking claw 101.
[0024]
On the other hand, the pointer is configured to include a pointer hardware base 14 and a diffusion light guide and a pointer cover (not shown). The pointer hardware base 14 includes a disc-shaped base end portion 141 provided with a pointer shaft (not shown) extending downward, and an elongated instruction portion 142 extending from the edge portion of the base end portion 141 in a substantially vertical direction with respect to the pointer shaft. It consists of. A plurality of light emitting elements, for example, LEDs are mounted on the instruction section 142 in an array at equal intervals along the longitudinal direction of the instruction section 142. The base end portion 141 is provided with a plurality of holes electrically connected to the plurality of light emitting elements so as to go around the pointer shaft. A plurality of connection pins 13 (corresponding to the electrical connection members in the claims) having springiness toward the outside are inserted through the plurality of holes.
[0025]
The plurality of connection pins 13 are attached to the plurality of holes provided in the base end portion 141 so as to extend downward, and are electrically connected to the plurality of light emitting elements, and at the center of the wiring board of the spiral FPC 12 The plurality of electrodes 12a formed on the inner surface of 120 are in contact with each other. That is, due to the outward spring property, each of the plurality of connection pins 13 reliably contacts the plurality of electrodes 12a. Further, when attaching the pointer, it is only necessary to insert the plurality of connection pins 13 from above in correspondence with the plurality of electrodes 12a. Although not shown, fixing means such as a lock claw and a hole for fixing the both are formed on the lower surface of the base end portion 141 and the cylindrical upper surface of the electrode holder. Thereby, the rotational torque of the rotating shaft 102 of the stepping motor 10 can be accurately transmitted to the pointer and the spiral FPC 12.
[0026]
Note that a diffusion light guide for guiding and diffusing light from a plurality of light emitting elements is covered on the pointer hardware base 14, and further, a light guide element that is slightly larger than the pointer hardware base and has a plurality of light emitting elements. A pointer cap having a slit along the line is covered. Through this slit, the light from the light emitting element that is lit is directed upward and is visually recognized by a driver or the like.
[0027]
The operation of the spiral FPC 12 used in the instrument having such a configuration will be described with reference to FIG. In the figure, the fixing parts 121a and 121b are fixed to the print base (corresponding to the stepping motor side in the claims). As described above, the two wiring board spiral portions 121 and 122 that have been bifurcated have equivalent spring properties, that is, Young's modulus, and therefore, in a state where the rotating shaft 102 of the stepping motor 10 has not yet rotated. The spring properties 121f and 122f of the two wiring board spirals 121 and 122 are balanced and stable in the state shown in FIG. For example, this state is adjusted to zero vehicle speed.
[0028]
From this state, when the speed is increased and the rotating shaft 102 of the stepping motor 10 starts to rotate clockwise, for example, in the figure, the spring property 122f acts in the forward direction and the spring property 121f acts in the opposite direction. However, they are stable in a balanced state. Here, since the spring property 121f of the spiral portion 121 and the spring property 122f of the spiral portion 122 are equivalent to each other and act in different directions, the spring property of the spiral FPC 12 viewed from the stepping motor 10 may be halved. Recognize.
[0029]
Conversely, when the rotating shaft 102 of the stepping motor 10 starts to rotate counterclockwise, for example, counterclockwise from the balanced state, the rotational torque of the stepping motor 10 and the spring property of the spiral FPC 12 are caused by the reverse action. Stable in a balanced state. Also in this case, since the spring property 121f of the spiral part 121 and the spring property 122f of the spiral part 122 are acting in different directions, the spring property of the spiral FPC 12 viewed from the stepping motor 10 may be halved. Recognize.
[0030]
In this way, the spring property of the spiral FPC 12 can be reduced while the full width of the spiral FPC 12 is maintained. Therefore, it is possible to prevent the stepping motor from stepping out and to give an accurate instruction. Further, since the holding torque of the stepping motor can be reduced, it is possible to contribute to miniaturization and cost reduction of the motor. Furthermore, since the pointer is supported by both of the two wiring board spirals, the rotational stability is also improved.
[0031]
Note that a power supply signal from the power supply circuit enters the plurality of electrodes of the fixing portions 121a and 122a from the printed circuit board, travels through the two wiring board spiral portions 121 and 122 that also function as lead wires, and reaches the plurality of electrodes 12a. . Then, power is supplied to the plurality of light emitting elements mounted on the instruction unit 142 of the pointer hardware base 14 via the plurality of connection pins 13 in contact with the plurality of electrodes 12a, and the plurality of light emitting elements are turned on. . Of course, all the light emitting elements may be lit or only one may be lit.
[0032]
As described above, according to the embodiment of the present invention, the two wiring board spiral portions having the same spring property in the spiral shape in the winding directions opposite to each other are maintained, while the full width of the printed wiring board is maintained. The spring property can be reduced with respect to the rotating direction. Therefore, it is possible to prevent the stepping motor from stepping out and to give an accurate instruction. Further, since the holding torque of the stepping motor can be reduced, it is possible to contribute to miniaturization and cost reduction of the motor.
[0033]
The present invention can be applied not only to a vehicle instrument but also to various instruments. Moreover, it is not necessary to be a speedometer. The present invention includes those modified without departing from the gist of the present invention.
[0034]
【The invention's effect】
As described above, according to the first aspect of the present invention, the central portion of the wiring board on which the electrode electrically connected to the pointer side is formed is attached to the base end portion of the pointer and integrated with the pointer. Rotate. Two wiring board spirals having a spiral shape in opposite winding directions are formed from the center of the wiring board toward the outside. In addition, a fixed portion that is fixed to a predetermined portion on the stepping motor side is formed in a part of each of the two wiring board spiral portions. The two wiring board spirals in the winding directions opposite to each other can reduce the spring property in both directions while maintaining the full width of the printed wiring board. Therefore, it is possible to prevent the stepping motor from stepping out and to give an accurate instruction. Further, since the holding torque of the stepping motor can be reduced, it is possible to contribute to miniaturization and cost reduction of the motor. Furthermore, since the pointer is supported by both of the two wiring board spirals, the rotational stability is also improved.
[0035]
According to the second aspect of the present invention, since the two wiring board spiral portions are formed by bifurcating one ribbon-like flexible printed wiring board, manufacturing is easy and cost reduction can be promoted. .
[0036]
According to the third aspect of the present invention, since the central portion of the wiring board to which the pointer is attached is also formed from a single ribbon-like flexible printed wiring board, manufacturing is easy and cost reduction can be promoted. In addition, since the electrode is formed on the inner side surface of the central portion of the wiring board, electrical connection with the pointer side is facilitated.
[0037]
According to the fourth aspect of the present invention, the spiral flexible printed wiring board having the two wiring board spirals as described above is fixed to a predetermined portion on the stepping motor side, and the pointer is provided at the center of the wiring board. By attaching, a stepping motor can be prevented from being stepped out and an instrument capable of giving an accurate instruction can be provided. Further, since the holding torque of the motor can be reduced, a small stepping motor can be applied, which can contribute to cost reduction of the instrument.
[0038]
According to the fifth aspect of the present invention, the electrical connection between the pointer side and the spiral flexible printed wiring board side is achieved by the connecting pin attached to the base end portion of the pointer so as to extend downward and having a spring property toward the outside. Connection can be made easily and reliably. That is, the assembling property of the instrument is improved.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a part of an instrument using a spiral flexible printed wiring board of the present invention.
2 is a perspective view showing a state before winding the spiral flexible printed wiring board of FIG. 1; FIG.
3 is a front view of the spiral flexible printed wiring board of FIG. 1. FIG.
[Explanation of symbols]
1 Meter 10 Stepping motor 11 Electrode holder 12 Spiral FPC
12a Electrode 120 Wiring board central part 121, 122 Wiring board spiral part

Claims (5)

In order to function as a lead wire for supplying power to the light emitting element mounted on the pointer that rotates around the pointer shaft, and to balance the rotational torque of the stepping motor that rotates the pointer, to stop the pointer at a predetermined indication position A spiral flexible printed wiring board having the spring property of
A wiring board center portion on which an electrode that is electrically connected to the pointer side is formed while the base end portion of the pointer is attached and rotates integrally with the pointer;
Two wiring board spirals formed in a spiral shape so as to be in mutually opposite winding directions from the center of the wiring board toward the outside;
A fixed portion that is a part of each of the two wiring board spiral portions and is fixed to a predetermined portion on the stepping motor side;
A spiral flexible printed wiring board characterized by comprising: The spiral flexible printed wiring board according to claim 1,
The two wiring board spiral portions are formed by bifurcating one ribbon-like flexible printed wiring board, one spiraling in the right-handed direction, and the other spiraling in the left-handed direction. ,
A spiral flexible printed wiring board characterized by the above. In the spiral flexible printed wiring board according to claim 2,
The wiring board center portion is formed by winding the vicinity of the end of the single ribbon-like flexible printed wiring board into a substantially cylindrical shape,
The electrode corresponding to the light emitting element is formed on the inner surface of the central portion of the wiring board,
A spiral flexible printed wiring board characterized by the above. An instrument using the spiral flexible printed wiring board according to any one of claims 1 to 3,
The fixing part of the wiring board is fixed to a predetermined part on the stepping motor side,
A light emitting element is mounted and rotated around a pointer shaft, and a base end of the pointer is attached to the center of the wiring board,
An electrical connection member for electrically connecting the light emitting element and the spiral flexible printed wiring board;
A cylindrical electrode holder that accommodates the central portion of the wiring board;
An instrument characterized by comprising: The instrument of claim 4,
The electrical connection member is a connection pin that is attached to the base end portion of the pointer so as to extend downward, is electrically connected to the light emitting element, and contacts the electrode by utilizing an outward spring property. ,
An instrument characterized by that.

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