JPH0634203U - Circuit board device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a circuit board device having a circuit including a variable resistor, which can be further thinned and has high reliability even on a metal substrate. [Structure] A support hole is formed through a circuit board having a circuit pattern, a bearing is arranged in the support hole, a resistance pattern is formed around the support hole on one side of the circuit board, and the bearing is rotatably slid. The rotary slider is rotatably supported on the bearings or the circuit board by pivotally supporting the slider and pressing a part of the rotary slider against the resistance pattern, and the rotation accompanying the rotation. It is a circuit board device in which a variable resistor whose resistance value changes by sliding on a resistance pattern of a slider is formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a circuit board device having a variable resistor, for example, an improvement of the circuit board device used for a thin motor for rotationally driving a floppy disk.

[0002]

[Prior art]

 Conventionally, this type of circuit board device has been provided with a variable resistor (volume) for adjusting the phase of the index signal in order to obtain an accurate index signal of a floppy disk to be rotationally driven.

As this circuit board device, there is known a configuration in which a discrete thin variable resistor 5 is mounted on a circuit board 3 on which a circuit pattern 1 is formed, as shown in FIG.

The variable resistor 5 includes a variable resistor main body 7, a resistance pattern (not visible) formed in the variable resistor main body 7, and a rotary adjustment pivotally supported by the variable resistor main body 7. The shaft 9 and a sliding piece (not visible) attached to the rotation adjusting shaft 9 inside the variable resistor body 7 so as to slide on the resistance pattern were formed on the variable resistor body 7. The connection electrode 11 and the circuit pattern 1 on the circuit board 3 are connected by soldering, or the connection terminals (not shown) formed on the variable resistor body 7 are inserted into the circuit board 3 and soldered to the circuit pattern 1. I was connected.

Reference numeral 13 in FIG. 3 denotes an adjustment hole in which the variable resistor 5 can be adjusted from the opposite side of the circuit board 3.

[0006]

[Problems to be solved by the device]

 However, in the above-described circuit board device, even though the variable resistor 5 is thin, it is a discrete type formed separately from the circuit board 3, and therefore the thickness is not so thin at present.

Moreover, in the configuration in which the adjustment hole 13 is formed in the circuit board 3 in order to adjust the variable resistor 5 from the opposite side, the rotation adjustment shaft 9 will not fit unless the adjustment hole 13 is accurately formed, or the rotation adjustment shaft Inconveniences such as contact of the circuit board 3 with the circuit board 3 occur, and particularly when the circuit board 3 is made of metal, the rotation adjusting shaft 9 easily hits the circuit board 3 and becomes an obstacle.

The present invention has been made to solve the above-mentioned conventional drawbacks, and an object of the present invention is to provide a circuit board device which can be further thinned and has high reliability even on a metal board.

[0009]

[Means for Solving the Problems]

 In order to solve such a problem, the present invention forms a support hole through a circuit board having a circuit pattern, arranges a bearing in the support hole, and forms a resistance pattern around the support hole on one side of the circuit board. , And the rotary slider is pivotally supported on the bearing, and the rotary slider can be rotated on the bearing or circuit board by pressing a part of the rotary slider against the resistance pattern. It has a structure in which a variable resistor whose resistance value is changed by sliding on the resistance pattern of the rotary slider that is supported by is formed.

[0010]

[Action]

 In the present invention equipped with such means, the rotary slider is directly supported in the support hole of the circuit board via the bearing, and a part of the rotary slider is pressed against the resistance pattern on the circuit board. When the rotary slider is rotated, the rotary slider slides on the resistance pattern and the resistance value changes.

[0011]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a circuit board device according to the present invention.

A circuit pattern 17 is formed on one surface (upper surface in the drawing) of the metal circuit board 15 via an insulating layer (not shown).

A support hole 19 is formed through the circuit board 15, and an insulating bearing 21 made of resin or the like is fixed to the support hole 19.

As shown in FIG. 2, on the upper surface of the circuit board 15, a resistance pattern 23 formed by applying a metal film resistance material in a circular arc shape around the support hole 19 is formed via an insulating layer (not shown). Formed, and one end thereof is connected to the circuit pattern 17.

Returning to FIG. 1, a resin bearing 21 is press-fitted and fixed in a support hole 19 formed in the circuit board 15, and a conductive rotating slider 27 is attached to the circuit board 15 in the bearing 21. The shaft is rotatably supported.

A pair of sliding contact projections 28, 28 are formed on the rotary slider 27 so as to project toward the circuit board 15. The sliding contact projections 28, 28 are formed on the circuit board 15. The resistance patterns 23, 23 are pressed to rotate and are connected to other circuit patterns 17, 17 to form a variable resistor 29.

The variable resistor 29 is connected to an index signal phase adjusting circuit formed in the circuit pattern 17 in order to obtain an accurate index signal of the floppy disk rotationally driven by the brushless motor.

In the circuit board device of the present invention thus configured, when the rotary slider 27 is rotated, the sliding contact protrusions 28, 28 of the rotary slider 27 slide on the resistance patterns 23, 23. It is possible to change the resistance value, and the rotary slider 27 is directly supported by the support hole 19 of the circuit board 15 through the bearing 21 and a part of the rotary slider 27 is supported. Since the structure is pressed onto the resistance pattern 23, the thickness dimension can be significantly reduced.

For example, compared with the conventional discrete type variable resistor 5, the thickness can be reduced to, for example, about 1/2, and the rotating slider 27 does not come into contact with the circuit board 15 to cause any inconvenience. There is no problem even if 15 is made of metal.

Moreover, since the rotary slider 27 is directly supported in the support hole 19 of the circuit board 15 via the bearing 21, the rotary slider 27 does not fit into the circuit board 15 or the circuit board 1 There is no problem in contact with the member 5 due to the characteristic.

[0021]

[Effect of device]

 As described above, according to the present invention, a support hole is formed by penetrating a circuit board, a bearing is arranged, and a resistance pattern is formed around the support hole on one surface of the circuit board. With the structure that the main part of the variable resistor is directly formed and fixed to the circuit board by pivotally supporting and partly pressing it to the resistance pattern, it is possible to make it even thinner, and even for metal boards. It is possible to provide a highly reliable circuit board device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a circuit board device according to the present invention.

FIG. 2 is a plan view showing an example of a resistance pattern of a circuit board device according to the present invention.

FIG. 3 is a cross-sectional view showing a conventional circuit board device.

[Explanation of symbols]

 1, 17 Circuit pattern 3, 15 Circuit board 5, 29 Variable resistor 7 Variable resistor body 9 Rotation adjusting shaft 11 Connection electrode 13 Adjusting hole 19 Support hole 21 Bearing 23 Resistance pattern 27 Rotating slider 28 Sliding contact protrusion

Claims (1)

[Scope of utility model registration request] 1. A circuit board having a circuit pattern and having a support hole formed therethrough, a bearing arranged in the support hole, and a resistance pattern formed around the support hole on one surface of the circuit board. A rotary slider that is rotatably supported by the bearing or a circuit board by being rotatably supported by the bearing and partly pressed against the resistance pattern; A circuit board device, comprising: a variable resistor that changes a resistance value by sliding on a resistance pattern of a slider.