JP3606056B2 - Instrument - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an instrument used for a vehicle instrument or the like, and in particular, a magnetic rotor of a drive coil in which a magnet rotor supported by a pointer shaft is inserted with a damper oil in a sealed hollow portion in a housing and wound around the outer periphery of the housing. Thus, the present invention relates to an instrument for rotating a pointer by rotating a magnet rotor.
[0002]
[Prior art]
Conventionally, a magnet rotor rotatably supported by a pointer shaft is inserted into a sealed hollow portion in a housing together with damper oil, and the magnet rotor is rotated by a driving magnetic field created by a driving coil wound around the housing. An instrument for moving a pointer is widely used in a vehicle instrument or the like.
[0003]
In this type of instrument, damper oil is put together with the magnet rotor in a sealed hollow part in the housing, and when the magnet rotor rotates, the viscous resistance of this damper oil suppresses or slows the movement of the magnet rotor and pointer shaft. The pointing operation of the pointer is performed stably. In addition, a shaft having the same outer diameter is usually used as the pointer shaft, and the bearing thereof has a structure that mainly receives a radial load.
[0004]
Therefore, a protrusion is provided around the shaft hole on the upper wall surface in the housing, and the protrusion 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 assembly in the thrust direction has been developed.
[0005]
[Problems to be solved by the invention]
The sealed space in the housing is filled with damper oil, and a part of the magnet rotor is immersed in the damper oil, and its viscous resistance suppresses the movement of the pointer shaft assembly including the magnet rotor. When rotating or when vibration is applied, the damper oil adheres to the periphery of the shaft hole on the upper surface inside the housing, that is, the portion surrounded by the protrusion due to the surface tension.
[0006]
At this time, when vibration or the like is applied to the instrument and the pointer assembly is moved in the axial direction, the damper oil attached around the pointer shaft or near the center of the magnet rotor is surrounded by the protrusion. Pressurized by the magnet rotor and pushed up to the upper bearing part that supports the pointer shaft, the damper oil leaks from a slight gap between the pointer shaft and the upper bearing part, and the dial of the instrument is soiled with oil. There is a problem that the damper oil is insufficient and the damper effect of the pointer is lowered.
[0007]
In particular, in a meter that has been flattened to reduce the thickness of the meter as much as possible, the thickness of the upper bearing portion (thickness in the axial direction) is reduced, so that damper oil can easily leak out of the upper bearing portion. There was a problem.
[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 the housing.
[0009]
[Means for Solving the Problems]
To achieve the above object, an instrument according to claim 1 of the present invention, in the closed hollow section in the housing, the magnet rotor which is rotatably supported by the pointer shaft is inserted with a damper oil part of the magnet rotor Is provided on the inner wall surface of the housing , and the pointer shaft is inserted in an instrument that rotates the magnet rotor by a driving magnetic field generated by a driving coil wound around the housing. that around the shaft hole, the annular projection which limits the upward movement of the magnet rotor is contactable with the upper surface of the magnet rotor, the said annular projection, the damper oil inside the annular convex portion When pressure is applied to the inside of the annular projection due to the upward movement of the magnet rotor when the magnet adheres, a notch for releasing the damper oil inside the annular projection is provided in the Have The features.
[0012]
According to a second aspect of the present invention, the annular convex portion can be provided with four notches at intervals of about 90 °.
[0013]
[Operation and effect of the invention]
In the instrument configured as described above, 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 down, and the pointer performs a stable instruction operation.
[0014]
When vibration or the like is applied to the meter and the pointer shaft including the magnet rotor moves in the axial direction within the housing, the upper surface of the magnet rotor comes into contact with the limit contact portion provided on the inner wall surface of the housing, and the magnet rotor moves upward. Is limited.
[0015]
At this time, when the damper oil is attached around the shaft hole of the inner wall surface of the housing, the damper oil receives pressure by the pressing of the magnet rotor, but the damper oil that has received the pressure is provided in the restriction contact portion. Since it escapes from the passage portion, 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 soiled due to the leakage of the damper oil or the damper oil is not insufficient, and the durability of the instrument can be improved.
[0016]
In addition, in this way, it is possible to eliminate the risk of the damper oil leaking from the gap of the upper bearing portion. Therefore, the thickness of the upper bearing portion can be reduced and the thickness of the instrument can be reduced, so that the instrument can be flattened. .
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of a cross coil type 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 upper housing 2 and the lower housing 3 are combined to form the housing 1.
[0018]
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.
[0019]
The pointer shaft 4 is fitted and fixed at the center of the magnet rotor 7, the lower shaft portion of the pointer shaft 4 protrudes below it, and the upper shaft portion protrudes above the pointer shaft 4. The lower shaft portion is supported by a lower bearing portion 6 provided at the center of the lower housing 3, and the upper shaft portion is supported by an upper bearing portion 5 provided at the center of the upper housing 2. The length of the upper bearing portion 5 is made as short as possible, thereby reducing the shape of the upper housing 2 and making the entire housing 1 thin so that the instrument is flattened.
[0020]
The steel ball 17 located in the back of the lower bearing portion 6 is inserted to prevent deformation of the housing side when the pointer is press-fitted into the pointer shaft 4.
[0021]
As described above, the upper bearing portion 5 is formed at the center of the upper housing 2, and the shaft hole for inserting the pointer shaft 4 is provided there. The periphery of the shaft hole on the inner wall surface of the upper housing 2 is provided. As shown in FIG. 2, an annular convex portion 8 is provided as a limiting contact portion. And this annular convex part 8 is provided with four notches 9 at intervals of about 90 ° as a passage part for letting out the damper oil inside.
[0022]
This notch 9 constitutes the same flat part as the inner wall surface of the housing. The height of the divided annular projections 8 is very low and small, but when the thrust in the thrust direction is applied to the magnet rotor 7 and it moves in the axial direction, the annular projections 8 are moved to the magnet rotor 7. The movement is limited by hitting the upper surface of the surface, and the thrust load is received.
[0023]
When the upper housing 2 is viewed from the inner surface (bottom surface) as shown in FIG. 2, the dial mounting portions 10 protrude from the left and right sides, and the coil bobbin separators 11 are provided at both the upper and lower sides. Further, four terminal guides 12 are provided for attaching the terminals 16 at four positions between each dial mounting portion 10 and each separator 11.
[0024]
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, silicon oil) 14 for applying a viscous resistance to the magnet rotor 7 and suppressing its movement is enclosed in the hollow portion in the housing 1. A pointer (not shown) is fitted to the tip of the pointer shaft 4 protruding upward from the housing 1.
[0025]
The terminal 16 is formed in a pin shape and is formed by providing a plate-like connection portion on the upper portion thereof, and the four terminals are inserted into the terminal guide 12 at the upper plate-like connection portion, and the lower housing. 3 is inserted into the hole provided in the outer peripheral portion from below and is fitted. The end of the drive coil 13 wound around the housing 1 is 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 bottom of the housing 1.
[0026]
In the cross coil type instrument configured as described above, when in use, the signal current is intermittently supplied to the four intersecting drive coils 13 at regular time intervals, and the four drive coils 13 and the magnet rotor 7 are used. The pointer shaft 4 rotates according to the generated vector of the generated magnetic field, and the pointer indicates a value corresponding to the current value.
[0027]
In this way, current is supplied to the drive coil 13, and the pointer shaft 4 and the magnet rotor 7 rotate to perform an instruction operation of the pointer. At this time, the damper oil 14 enters the sealed space in the housing 1. Since the magnet rotor 7 is partially filled and 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 indicating operation. .
[0028]
When vibration or the like is applied to the instrument 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 caused by the annular convex portion 8 on the inner wall of the upper housing 2. When the upper surface of the magnet rotor 7 hits, the thrust load is limited by the annular projection 8. At this time, if the damper oil adheres to the inside of the annular projection 8, Pressure is applied to part of the damper oil. However, since the annular protrusion 8 is provided with the notch 9, the damper oil is pushed out of the annular protrusion 8 from the notch 9, and the increase in the pressure of the damper oil in the annular protrusion 8 is suppressed. Is done. For this reason, the malfunction which damper oil leaks from the clearance gap between the upper bearing parts 5 can be prevented.
[0029]
Thus, since the annular convex portion 8 is provided around the shaft hole of the upper bearing portion on the inner wall surface of the upper housing 2 and the notched portion 9 is provided in the annular convex portion 8, the damper oil is placed inside the annular convex portion 8. Even when pressure is applied to the magnet rotor due to the movement of the magnet rotor due to vibration or the like, the pressure of the damper oil is released from the notch 9, so that no pressure is applied to the annular convex portion 8, and the damper oil rises. Leakage from the gap of the bearing portion 5 is prevented. Therefore, even if the instrument is flattened and the upper bearing part is shortened, the leakage of the damper oil can be effectively prevented, and the problem that the dial is soiled with the damper oil or the lack of the damper oil is eliminated. Can do.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a cross coil type instrument showing an 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 6-lower bearing 7-magnet rotor 8-annular projection 9-notch 14-damper oil

Claims (2)

A magnet rotor rotatably supported by a pointer shaft is inserted into the sealed hollow portion in the housing together with the damper oil, and a part of the magnet rotor is immersed in the damper oil and wound around the housing. In an instrument for rotating the magnet rotor by a drive magnetic field generated by a drive coil,
An annular convex portion provided on the inner wall surface of the housing and around the shaft hole into which the pointer shaft is inserted is provided so as to be able to contact the upper surface of the magnet rotor,
The said annular projection, wherein when the damper oil inside the annular convex portion is applied a pressure to the inside of the annular protrusion by upward movement of the magnet rotor when adhering the inner annular protrusion A notch for allowing the damper oil to escape to the outside is provided. Instrument according to claim 1 mounting, characterized in that said notch portions are provided four at intervals of about 90 ° to the annular convex portion.

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