JPH0429417Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to improvements in movable magnet meters such as automobile fuel gauges, thermometers, motorcycle fuel gauges, and voltmeters.

[Prior Art] In general, this type of meter is a rectangular instrument with protruding legs 2 having electrodes 1 embedded upward and downward on each diagonal, as shown in FIGS. 1, 2, and 3. The upper and lower bodies 3 of the shape are overlapped to form a sealed cavity 4, and a magnet 6 fixed orthogonally to the pointer shaft 5 pivotally supported by the body 3 is disposed in the space of the cavity 4. , and the coil 7 is wound crosswise from the outside of the main body 3, and the magnet 6 is rotated by a synthetic magnetic field generated in proportion to the energization of the coil 7,
The pointer 8 attached to the pointer shaft 5 is used as a fuel gauge or the like by comparing and reading the pointer 8 with a dial (not shown) mounted on the leg 2. Note that damper oil (not shown) is injected into the cavity 4 to immerse the magnet 6 together with the pointer shaft 5.

Incidentally, although sintered ferrite or rolled magnets are used as the magnets 6 in the conventional instruments,
In this case, since the sintered ferrite is easily broken and the rolled magnet is thin, it is essential to interpose a restraining member 9 between the magnet 6 and the pointer shaft 5 as shown in FIG. The caulking margin 9a is caulked to the magnet 6 to form a bearing portion of the pointer shaft 5.

[Problem to be solved by the invention] In the conventional meter described above, the magnet 6 has a holding member 9.
In addition to attaching the two parts, ie, the pointer shaft 5 and the pointer shaft 5, it is necessary to swage the swage 9a of the holding member 9. Therefore, there is a problem in that the number of parts increases, and a great deal of time is wasted in attaching the pointer shaft 5 to the magnet 6, which impedes mass production. In addition, attaching the pointer shaft 5 through the restraining member 9 as described above causes a decrease in the accuracy of attaching the pointer shaft 5, which makes it difficult to determine the center of the pointer shaft 5, which makes it difficult to measure the instrument. There was a risk that a major problem would arise in the indication performance.

Therefore, the present invention provides a movable magnet type meter that simplifies the installation work of the pointer shaft, improves the installation accuracy of the pointer shaft, enhances the indicating performance of the meter, and further improves the responsiveness of the meter. With the goal.

[Means for Solving the Problems] The present invention incorporates a magnet in the cavity of the bobbin body, winds coils in the bobbin body crosswise, and fixes the end of the pointer shaft perpendicular to the magnet. In a movable magnet type instrument in which a pointer is attached to the tip of a pointer protruded from the inside of the bobbin body to the outside, and the pointer moves the magnet angularly by the resultant magnetic field of the coil, the pointer measures the pointer. The above-mentioned magnet, which is disposed so as to move angularly, is formed of a plastic magnet, and a mounting hole is formed at the center of rotation of the plastic magnet, and the above-mentioned pointer shaft protrudes from the surface of the plastic magnet at the periphery of this mounting hole. The pointer shaft is press-fitted into the mounting hole in a direction perpendicular to the plastic magnet.

[Function] With the above configuration, the pointer shaft can be press-fitted directly into the mounting hole formed at the center of rotation of the lightweight plastic magnet at the correct center position without using a restraining member. The work is simplified, and the installation accuracy of the pointer shaft and the indication performance and responsiveness of the instrument can be improved. Also,
The contact area between the magnet and the inner wall of the cavity due to movement of the magnet in the direction of the pointer axis can be reduced by the raised portion, reducing mutual friction and providing good responsiveness of the meter.

[Example] Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

In FIG. 6, reference numeral 11 denotes a cross-coil type movable magnet type instrument body, and this instrument body 11 is divided into upper and lower parts, with upper and lower bodies 12 and 1 being rectangular bobbin bodies.
A plastic magnet 14 is rotatably disposed within the plastic magnet 14, and a pair of coils are wound around the outer circumferences of the upper and lower bodies 12 and 13 at an angle to each other so as to surround the plastic magnet 14. 15 and 16, and by inputting a current corresponding to the measured amount at the detection point to the terminals of the coils 15 and 16, the coils 15 and 1 are connected in proportion to this current.
6 is generated, and the plastic magnet 14 rotates in the direction of the synthetic magnetic field. Therefore, the pointer 18 attached to the tip of the pointer shaft 17 press-fitted in the direction orthogonal to the center of rotation of the plastic magnet 14, It is formed so that the measurement quantity can be indicated using a dial (not shown). In addition, the upper and lower bodies 1
The plastic magnet 14 is disposed in the sealed cavity 19 formed by polymerizing the needles 2 and 13. In this embodiment, the plastic magnet 14 is immersed together with the pointer shaft 17 in damper oil (not shown). ing. 20 is the coil 15,
16 is a magnetic shielding cylindrical case containing the upper and lower bodies 12 and 13 wrapped around each other; 21 is the upper and lower bodies 12 and 1;
These are mounting bolts that extend downward through the cylindrical case 20 from the lower ends of the leg portions 12a and 13a that protrude diagonally from each other.

As shown in FIGS. 4 and 5, a mounting hole 22 is formed at the center of rotation of the plastic magnet 14.
The pointer shaft 17 is directly press-fitted and fixed in the orthogonal direction. 23 in Figure 4 is plastic magnet 1
4 is an annular protuberance formed on the periphery of the mounting hole 22 so as to protrude from the surface of the plastic magnet 14.

As mentioned above, the embodiment of the present invention has coils 15, 1
The plastic magnet 14 is formed into a flat plate shape, and the plastic magnet 14 has a molding shrinkage rate of 0.2 to 0.5%, which is higher than that of conventional magnets. Since the plastic magnet 14 is significantly smaller than 15 to 20% of the sintered ferrite, dimensional accuracy is improved, and the specific gravity of the plastic magnet 14 is 0.7 times that of the sintered ferrite. It is lightweight compared to the pointer shaft 1.
The load applied to 7 is reduced, and the responsiveness and followability of the instrument are improved.

In addition, since the plastic magnet 14 has superior compressive stress σ compared to conventional magnets, the pointer shaft can be directly inserted into the mounting hole 22 formed at the center of rotation of the plastic magnet 14 without intervening a restraining member. 17
The center of the pointer shaft 17 can be press-fitted, which eliminates the disadvantages of conventional instruments, such as the fact that the pointer shaft tends to be eccentric due to the intervening restraining member and the indication characteristics may vary easily. can be determined, and stable indicating characteristics with little variation can be obtained.

Furthermore, in this type of general movable magnet type instrument, the pointer shaft 17 is inserted into a recess formed in the lower part of the cavity 19, and the pointer shaft 17 is inserted into the hole in the main body 12.
The magnet 14 is placed with a predetermined width from the inner wall of the cavity 19, and the composite magnetic field of the coils 15 and 16 causes the pointer shaft 17 to be
The magnet 14 fixed to the body follows and moves angularly, but the pointer shaft 17, which is pivotally supported by the upper and lower bodies 12 and 13, does not move in the thrust direction of the pointer shaft 17, especially in the hole portion of the body 12. Since the movement of the magnet 14 is not regulated, the pointer shaft 17 may move up and down in the vibration atmosphere of the vehicle, and the entire surface of the magnet 14 may come into contact with the inner wall of the cavity 19. Although there was a risk that the responsiveness of the instrument would be adversely affected, by providing the protrusion 23 protruding from the surface of the plastic magnet 14 on the periphery of the mounting hole 22, even if the magnet 14 moves, the inner wall of the cavity 19 can be maintained. There is a raised part 2 with a small area.
3 come into contact with each other, the contact area between the magnet 14 and the inner wall of the cavity 19 becomes smaller, the friction is reduced, and stable indicating characteristics of the instrument are obtained.As shown in FIG. As it is, the height of the mounting hole 22 is increased, and the pointer shaft 1
It is possible to increase the amount of press-fit at 7 to improve the mounting strength.

Further, since there is no intervening holding member, the number of parts can be reduced, and the work of caulking the interference of the holding member is eliminated, so the workability of attaching the pointer shaft 17 is significantly improved and mass productivity is enhanced. Plastic magnet 14 also has the manufacturing advantage that raised portion 23 can be integrally molded.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the gist of the present invention.

[Effects of the Invention] The present invention is a movable magnet type instrument in which a magnet is built into the hollow portion of a bobbin body, a coil is wound crosswise around the bobbin body, an end of a pointer shaft fixed perpendicular to the magnet protrudes from the inside to the outside of the bobbin body, a pointer is attached to the tip of the end, and the magnet is moved angularly by the composite magnetic field of the coils to indicate and measure with the pointer. The magnet arranged to move angularly by the composite magnetic field of the coils is formed from a plastic magnet, a mounting hole is formed at the center of rotation of the plastic magnet, an annular protrusion is formed around the periphery of the mounting hole that protrudes beyond the surface of the plastic magnet and restricts the movement of the pointer shaft in the thrust direction, and the pointer shaft is press-fitted and fixed into the mounting hole directly perpendicular to the plastic magnet,
It is possible to provide a moving magnet type instrument that simplifies the work of attaching the pointer shaft and can improve the attachment accuracy of the pointer shaft and the indication characteristics and responsiveness of the instrument.

[Brief explanation of the drawing]

The drawings are examples. Figure 1 is a plan view of a conventional meter, Figure 2 is a sectional view showing the structure of the magnet and pointer shaft of the conventional meter, Figure 3 is a sectional view of the conventional meter, and Figure 4 is a sectional view of the conventional meter. The figure is a sectional view showing the structure of the plastic magnet and pointer shaft of the proposed meter, FIG. 5 is a perspective view thereof, and FIG. 6 is a sectional view of the proposed meter. 14...Plastic magnet, 15, 16
... Coil, 17 ... Pointer shaft, 19 ... Hollow part,
22... Attachment hole, 23... Protrusion.

Claims (1)

[Scope of utility model registration request] A magnet is built into the hollow part of the bobbin body, and a coil is wound crosswise around the bobbin body.
The end of a pointer shaft fixed perpendicular to the magnet is protruded from the inside of the bobbin body to the outside, a pointer is attached to the tip, and the magnet is angularly moved by the combined magnetic field of the coil to indicate and measure with the pointer. In such a movable magnet type instrument, the magnet arranged to be angularly moved by the combined magnetic field of the coil is formed of a plastic magnet, and a mounting hole is formed at the rotation center of the plastic magnet,
An annular protuberance is formed on the periphery of the mounting hole to protrude from the surface of the plastic magnet and restrict the movement of the pointer shaft in the thrust direction, and the pointer shaft is inserted into the mounting hole in a direction directly orthogonal to the plastic magnet. A movable magnet type instrument characterized by being press-fitted and fixed.