JP2000039453A - Measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring instrument which can prevent a damper oil from being leaked from the upper bearing part of a housing. SOLUTION: In a measuring instrument, a magnet rotor 7 which is supported by a pointer shaft 4 so as to be freely rotatable is inserted, together with a damper oil 14, into an airtight hollow part inside a housing 1, and the magnet rotor 7 and the pointer shaft 4 are turned by a driving magnetic field generated by a driving coil 13 which is wound on the circumference of the housing 1. A ring-shaped protrusion part 8 which is used to limit the movement in the axial direction of the magnet rotor 7 is formed around a shaft hole on the inner wall surface of the housing 1. Since a cutout part 9 is formed on the ring-shaped protrusion part 8, the damper oil 14 is pushed out to the outside of the ring-shaped protrusion part 8 from the cutout part 9, and a rise in the pressure of the damper oil 14 inside the ring-shaped protrusion part 8 is suppressed. As a result, it is possible to prevent a trouble that the damper oil 14 is leaked from the gap of an upper bearing part 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an instrument used for an instrument for a vehicle and the like, and more particularly, to a magnet rotor supported by a pointer shaft and a damper oil inserted into a closed hollow portion in a housing, and to an outer periphery of the housing. The present invention relates to an instrument for rotating a pointer by rotating a magnet rotor by a magnetic field of a wound drive coil.

[0002]

2. Description of the Related Art Conventionally, in a closed hollow portion in a housing,
A meter that moves a pointer by inserting a magnet rotor rotatably supported by a pointer shaft together with damper oil and rotating a magnet rotor by a drive magnetic field generated by a drive coil wound around a housing is a vehicle instrument. Etc. are widely used.

In this type of instrument, damper oil is put together with a magnet rotor in a closed hollow portion in a housing, and when the magnet rotor rotates, the movement of the magnet rotor and the pointer shaft is suppressed or slowed by viscous resistance of the damper oil. In this way, the operation of instructing the pointer is performed stably. In addition, a shaft having the same outer diameter is usually used for the pointer shaft, and the bearing has a structure mainly receiving a load in a radial direction.

In view of the above, a projection is provided on the upper wall surface in the housing so as to protrude around the shaft hole, and the projection can be brought into contact with the upper surface of the magnet rotor, thereby receiving the thrust load of the pointer shaft and the magnet rotor. An instrument having a structure for restricting the movement of the pointer shaft assembly in the thrust direction has been developed.

[0005]

The closed space in the housing is filled with damper oil, and a part of the magnet rotor is immersed in the damper oil. Although the movement is suppressed, when the pointer rotates or when vibration is applied, the damper oil adheres to the periphery of the shaft hole on the upper surface in the housing, that is, the portion surrounded by the projection, due to the surface tension.

At this time, when vibration or the like is applied to the meter and the pointer assembly is moved in the axial direction, the damper attached to the periphery of the pointer shaft and the vicinity of the center of the magnet rotor in the portion surrounded by the projection. Oil is pressurized by the magnet rotor and pushed up to the upper bearing part supporting the pointer shaft.Damper oil leaks from a slight gap between the pointer shaft and the upper bearing, and the dial of the instrument And the shortage of damper oil causes a decrease in the damper effect of the pointer.

In particular, in a flattened instrument in which the thickness of the instrument is made as thin as possible, the thickness of the upper bearing portion (thickness in the axial direction) is reduced, so that the damper oil further leaks out from the upper bearing portion. There was a problem that was easy to do.

[0008] The present invention has been made in view of the above points, and an object of the present invention is to provide an instrument capable of preventing leakage of damper oil from inside a housing.

[0009]

According to a first aspect of the present invention, a magnet rotor rotatably supported by a pointer shaft in a closed hollow portion in a housing together with damper oil is provided. In a meter that rotates a magnet rotor by a driving magnetic field generated by a driving coil inserted and wound around the housing, a limiting contact portion that restricts upward movement of the magnet rotor around an axial hole in an inner wall surface of the housing. Is provided so as to be able to contact the upper surface of the magnet rotor, and the restriction contact portion is provided with a passage portion for allowing the damper oil inside the restriction contact portion to escape to the outside.

Here, as the restriction contact portion, an annular convex portion can be provided around the shaft hole in the inner wall surface of the housing.

Further, as a passage portion for allowing the damper oil to escape to the outside, a notch portion can be provided in the annular convex portion.

Further, four notches can be provided in the annular convex portion at intervals of about 90 °.

[0013]

In the meter having the above-described structure, when the drive coil is energized, the pointer shaft rotates together with the magnet rotor in accordance with the magnetic field generated by the drive coil, and the pointer indicates the indicated value. At this time, the magnet rotor rotates while receiving the viscous resistance of the damper oil in the housing, the rotation of the pointer shaft is suppressed or slowed, and the pointer performs a stable pointing operation.

When a pointer or the like including the magnet rotor moves in the axial direction in the housing due to vibration or the like applied to the instrument, the upper surface of the magnet rotor comes into contact with a limiting contact portion provided on the inner wall surface of the housing, and Upward movement is restricted.

At this time, if damper oil adheres around the shaft hole on the inner wall surface of the housing, the damper oil is subjected to pressure by the pressing of the magnet rotor. To escape from the passage provided in
The pressure of the damper oil is not applied to the inside of the upper bearing portion, and the damper oil is prevented from leaking from the gap between the upper bearing portion and the pointer shaft. Therefore, the dial is not stained by the leakage of the damper oil, and the damper oil is not deficient, so that the durability of the instrument can be improved.

In addition, since the risk of damper oil leaking from the gap between the upper bearing portions can be eliminated, the thickness of the upper bearing portion is reduced to reduce the thickness of the gauge, thereby making the gauge flat. be able to.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of a cross-coil instrument to which the present invention is applied. Reference numeral 2 denotes an upper housing made of synthetic resin, and reference numeral 3 denotes a lower housing made of synthetic resin. The housing 1 is formed by combining the upper housing 2 and the lower housing 3.

A sealed hollow portion is formed in the housing 1, and a magnet rotor 7 made of a permanent magnet such as ferrite is rotatably disposed in the hollow portion.

The pointer shaft 4 is inserted and fixed at the center of the magnet rotor 7, a lower shaft portion of the pointer shaft 4 projects below the magnet shaft 7, and an upper shaft portion projects above the pointer shaft 4. The lower shaft is supported by a lower bearing 6 provided at the center of the lower housing 3, and the upper shaft is supported by an upper bearing 5 provided at the center of the upper housing 2. The length of the upper bearing portion 5 is made as short as possible, whereby the shape of the upper housing 2 is made thinner and the entire housing 1 is made thinner, thereby making the gauge flat.

The steel ball 17 located at the back of the lower bearing 6
Are inserted to prevent deformation of the housing when the pointer is pressed into the pointer shaft 4.

As described above, the upper bearing portion 5 is formed in the center of the upper housing 2, and a shaft hole for inserting the pointer shaft 4 is provided in the upper bearing portion 5. The shaft hole in the inner wall surface of the upper housing 2 is provided. Around the hole, as shown in FIG. 2, an annular convex portion 8 protrudes as a limited contact portion. The annular projection 8 is provided with four notches 9 at intervals of about 90 ° as passages for allowing the damper oil inside to escape to the outside.

The cutout 9 forms the same flat portion as the inner wall surface of the housing. Although the height of the divided annular convex portion 8 is very low and small, when a load in the thrust direction is applied to the magnet rotor 7 and moves in the axial direction, the annular convex portion 8 To limit its movement and receive the thrust load.

When the upper housing 2 is viewed from the inner surface (bottom surface) as shown in FIG. 2 on the outer peripheral portion of the upper housing 2, dial mounting portions 10 are provided on both left and right sides, and coil bobbins are provided on both upper and lower sides. Separators 11 are protruded, and four terminal guides 12 are provided at four locations between each dial mounting portion 10 and each separator 11 for mounting terminals 16.

On the other hand, a total of four drive coils 13 are wound around the outer periphery of the housing 1 in directions orthogonal to each other.
Further, a damper oil (for example, silicone oil) 14 for providing viscous resistance to the magnet rotor 7 and suppressing its movement is sealed in the hollow portion inside the housing 1. A pointer (not shown) is fitted to the distal end of the pointer shaft 4 projecting upward from the housing 1.

The terminal 16 is formed in the shape of a pin and is provided with a plate-shaped connection at the top thereof. The four terminals are inserted into the terminal guide 12 with the plate-shaped connection at the top. Is inserted from below into a hole provided in the outer peripheral portion of the lower housing 3 and fitted. The ends of the drive coil 13 wound around the housing 1 are connected to the upper ends of these terminals 16. Further, a metal shield case 15 is covered from below so as to surround the outer periphery and the bottom of the housing 1.

In the crossed coil type instrument constructed as described above, in use, a signal current is intermittently supplied to four intersecting drive coils 13 at a fixed time interval, so that the four drive coils 13 and the magnet rotor 7, the pointer shaft 4 rotates in accordance with the resultant vector of the magnetic field generated by the pointer 7 and the pointer indicates a value corresponding to the current value.

As described above, the current is supplied to the drive coil 13, and the pointer shaft 4 and the magnet rotor 7 rotate to perform the pointer operation. At this time, the damper oil 14 is placed in the closed space in the housing 1. Filled about 1/3, magnet rotor 7
Is immersed in the damper oil 14, the viscous resistance suppresses the movement of the pointer shaft assembly including the magnet rotor 7, and the pointer performs a stable pointing operation.

When vibration or the like is applied to the meter and the pointer shaft assembly including the pointer shaft 4 and the magnet rotor 7 vibrates in the axial direction, the movement of the pointer shaft 4 and the magnet rotor 7 is controlled by the upper housing 2.
The upper surface of the magnet rotor 7 is limited by the upper surface of the magnet rotor 7 hitting the annular convex portion 8 of the inner wall, and the load in the thrust direction is received by the annular convex portion 8. If so, pressure is applied to the damper oil at that portion. However, since the notch 9 is provided in the annular protrusion 8, the damper oil is pushed out of the annular protrusion 8 from the notch 9, and the pressure increase of the damper oil in the annular protrusion 8 is suppressed. Is done. Therefore, it is possible to prevent a problem that the damper oil leaks from the gap of the upper bearing portion 5.

As described above, the annular projection 8 is provided on the inner wall surface of the upper housing 2 around the shaft hole of the upper bearing,
Since the notch 9 is provided in the annular convex portion 8, even if damper oil adheres to the inside of the annular convex portion 8 and pressure is applied thereto due to movement of the magnet rotor due to vibration or the like, the pressure of the damper oil does not increase. Since the cutout 9 is removed, no pressure is applied to the annular convex portion 8, and the damper oil is prevented from leaking from the gap of the upper bearing portion 5. Therefore, even for an instrument that is flattened and the upper bearing portion is shortened, it is possible to effectively prevent the leakage of damper oil, and to solve the problems of contaminating the dial with damper oil and causing shortage of damper oil. Can be.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a cross-coil type instrument showing one embodiment of the present invention.

FIG. 2 is a bottom view of the upper housing 2. FIG.

[Explanation of symbols]

 1-housing 2-upper housing 3-lower housing 4-pointer shaft 5-upper bearing portion 6-lower bearing portion 7-magnet rotor 8-annular convex portion 9-notch portion 14-damper oil

Claims (4)

[Claims] 1. A magnet rotor rotatably supported by a pointer shaft is inserted into a closed hollow portion in a housing together with damper oil, and the magnet rotor is driven by a driving magnetic field generated by a driving coil wound around the housing. In a meter for rotating a rotor, a limiting contact portion for limiting upward movement of the magnet rotor is provided around an axial hole in an inner wall surface of the housing so as to be able to contact an upper surface of the magnet rotor. The instrument is provided with a passage portion for allowing the damper oil inside the portion to escape to the outside. 2. The instrument according to claim 1, wherein an annular convex portion is provided around the shaft hole on the inner wall surface of the housing as the restriction contact portion. 3. The instrument according to claim 2, wherein a notch is provided in said annular convex portion as a passage portion for allowing said damper oil to escape to the outside. 4. The annular convex portion has a cutout of about 90 °.
4. The instrument according to claim 3, wherein four are provided at intervals of: