JPH0634659A - Movement for instrument - Google Patents

Abstract

PURPOSE:To obtain a movement for an instrument of which the thickness is small and which enables attainment of a large driving force. CONSTITUTION:This movement is constructed of a rotating shaft 2, a coil bobbin 4 so disposed around the rotating shaft 2 as to intersect the axial direction of the rotating shaft 2 perpendicularly, a plurality of coils 5 wound round on the coil bobbin 4 so that magnetic fields generated thereby cross each other and that each magnetic field intersects the axial direction of the rotating shaft 2 perpendicularly, an inner case 7 shaped in a bottomed tube and fitted to the rotating shaft 2, and a cylindrical magnet 8 magnetized in the circumferential direction and fitted on the inner peripheral surface of the inner case 7 so that the inner peripheral surface thereof intersects perpendicularly the magnetic fields generated by the coils 5 in a plurality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an instrument movement used for, for example, a speedometer, an engine tachometer, a water temperature gauge, etc. mounted on an automobile.

[0002]

2. Description of the Related Art As a conventional movement for an instrument as described above, a plurality of coils that generate mutually orthogonal magnetic fields are supplied with currents that change according to measured values, and the magnetic fields generated by the coils are combined. There is used a magnet that rotates a magnet as a rotor and rotates a pointer through a rotation shaft attached to the magnet. Such an instrument movement is formed by winding a pair of coils so as to be orthogonal to each other on the outer peripheral portion of a coil bobbin that penetrates a shaft attached to a magnet housed inside, and forms the pair of coils in the thickness direction of the coil bobbin. It is formed by overlapping and winding in the (rotational axis direction).

[0003]

Since the conventional instrument movement is formed by superposing and winding a pair of coils in the thickness direction (rotational axis direction) of the coil bobbin, the thickness thereof becomes large. In addition, since the magnet housed in the coil bobbin is small in order to increase the driving force, it is necessary to increase the number of turns of the pair of coils, resulting in an inconvenience that the thickness is further increased.

Therefore, the present applicant has previously proposed a measuring instrument movement (Japanese Utility Model Laid-Open No. 1-39666) in which a pair of coils are arranged around a magnet in order to reduce the thickness of the measuring instrument movement. However, even in this instrument movement, the magnet attached to the rotary shaft is located at the center, and therefore the magnet is small. Therefore, in order to increase the driving force, the number of turns of the pair of coils wound around the coil bobbin must be increased, and the thickness of the instrument movement cannot be made very thin.

The present invention has been made in order to solve the above-mentioned inconvenience, and provides a movement for an instrument capable of reducing the thickness and obtaining a large driving force.

[0006]

A measuring instrument movement according to the present invention includes a rotating shaft, and a coil bobbin arranged around the rotating shaft so as to be orthogonal to the axial direction of the rotating shaft.
A plurality of coils wound around a coil bobbin so that the magnetic fields generated by each intersect and the magnetic fields are orthogonal to the axial direction of the rotating shaft, a magnet support attached to the rotating shaft, and a plurality of inner peripheral surfaces. And a cylindrical magnet attached to the magnet support so as to be orthogonal to the magnetic field generated by the coil.

[0007]

In the instrument movement according to the present invention, when the electric current that changes according to the measured value is supplied to the plurality of coils, the plurality of coils generate a magnetic field through the cylindrical magnet and the magnet support. The rotating shaft with the magnet attached rotates.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view showing a structure of an instrument movement which is an embodiment of the present invention, and FIG. 2 is a plane sectional view corresponding to line AA in FIG. Note that FIG. 1 is a side sectional view taken along the line BB of FIG. 2, and in FIG. 2, the rotary shaft and the positioning member are omitted.

In FIGS. 1 and 2, reference numeral 1 denotes a case, which is composed of a circular lower case 1d and a bottomed cylindrical upper case 1u which covers the lower case 1d. 2 is a rotary shaft whose one end is rotatably supported at the center of the lower case 1d,
3 is a positioning member attached to the lower case 1d side of the rotating shaft 2 and 4 is a coil bobbin.
Are arranged around the rotary shaft 2 so as to be orthogonal to the axial direction of the rotary shaft 2.

Reference numeral 5 denotes a pair of coils, which are wound around the coil bobbin 4 such that the magnetic fields generated by the coils are orthogonal to each other and the magnetic fields are orthogonal to the axial direction of the rotating shaft 2. Reference numeral 6 denotes a terminal provided on the coil bobbin 4, to which one end of each coil 5 is connected and which penetrates the lower case 1d. Reference numeral 7 denotes an inner case as a magnet support, which has a bottomed cylindrical shape that covers the lower case 1d, and is attached to the rotary shaft 2 in a state where the axial direction of the rotary shaft 2 is positioned by the positioning member 3.

Reference numeral 8 denotes a magnet, which is magnetized in the circumferential direction and is attached to the inner peripheral surface of the inner case 7 so that the inner peripheral surface thereof is orthogonal to the magnetic fields generated by the pair of coils 5. The upper case 1u is disposed outside the inner case 7 so as to cover the lower case 1d on the rotary shaft 2 and supports the other end portion of the rotary shaft 2.

Next, the operation will be described. First, when a current, which changes according to a measurement value, is supplied from a control unit (not shown) to the terminals 6 connected to the pair of coils 5 forming the stator, the magnetic fields generated by the coils 5 are combined in the combined magnetic field direction. The magnet 8 as a rotor is rotated. At the same time, the rotating shaft 2 to which the magnet 8 is attached is also rotated via the inner case 7. Therefore, the pointer (not shown) attached to the other end of the rotary shaft 2 can be rotated.

As described above, according to the embodiment of the present invention, the inner peripheral surface of the cylindrical magnet 8 constituting the rotor is provided around the pair of coils 5 wound around the coil bobbin 4 constituting the stator. Since it is arranged so as to be orthogonal to the magnetic field generated by each coil 5, the instrument movement can be made thin. Further, since the magnet 8 is disposed on the outer circumference of the pair of coils 5, it is possible to use a magnet that is large and generates a strong magnetic field. Since the magnet can be made stronger without increasing the number of windings, the instrument movement can be made thin.

In the above embodiment, one end of the rotary shaft 2 is rotatably supported by the lower case 1d, but one end of the rotary shaft 2 may be rotatably supported by the coil bobbin. Although the example using the positioning member 3 has been described, the positioning member 3 can be omitted by directly attaching the inner case 7 to the rotary shaft 2. Furthermore, although the magnet support has been described as an example in which the bottomed cylindrical inner case 7 is used,
It may be simply a flat plate.

[0015]

As described above, according to the present invention, the inner peripheral surface of the cylindrical magnet that constitutes the rotor is generated around each of the plurality of coils wound around the coil bobbin that constitutes the stator. Since it is arranged so as to be orthogonal to the magnetic field, the instrument movement can be made thin. Also,
Even when the driving force is increased, the magnet is arranged on the outer circumference of the coil, so the magnet can be made large and strong without increasing the number of turns of the coil, so the instrument movement can be made thin. be able to.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a configuration of an instrument movement according to an embodiment of the present invention.

FIG. 2 is a plan sectional view corresponding to line AA in FIG.

[Explanation of symbols]

 1 case 1u upper case 1d lower case 2 rotating shaft 3 positioning member 4 coil bobbin 5 coil 6 terminal 7 inner case 8 magnet

Claims (1)

[Claims] 1. A rotating shaft, a coil bobbin arranged around the rotating shaft so as to be orthogonal to the axial direction of the rotating shaft, and magnetic fields generated by the coil bobbins intersect with each other and the axial direction of the rotating shaft. A plurality of coils wound around the coil bobbin so that the magnetic fields are orthogonal to each other; a magnet support attached to the rotating shaft; and an inner peripheral surface of the coil support that is orthogonal to magnetic fields generated by the plurality of coils. A cylindrical magnet attached to the magnet support,
Movement for instruments equipped with.