JPS5842919A - Buffering device of pointer shaft for measuring instrument - Google Patents

Abstract

PURPOSE:To completely prevent oil for buffering from leaking out, to simplify the structure, and to decrease the number of parts, by sealing the buffering oil, provided in a supporting device, with a magnetic fluid. CONSTITUTION:Magnetic poles 6 are formed near the circumferential edge of the opening part of an oil cap 2, and magnetic poles 7 having the opposite polarity to the magnetic poles 6 are also formed on a pointer shaft 1 opposed to the magnetic poles 6. The magnetic poles 6 and 7 are formed annularly at the circumferential edge of the oil cap 2 and on the pointer shaft 1, respectively. The oil cap 2 contains buffering oil 8 and a magnetic fluid 9 is charged on it. The magnetic fluid 9 between the magnetic poles 6 and 7 is fixed at its position through the magnetic operation of the magnetic poles 6 and 7, and also completely seals the buffering oil by covering the buffering oil in a liquid state, preventing its leakage. Thus, the structure is simplified and the number of parts is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shock absorber for a meter pointer shaft, and more particularly to a shock absorber for a meter pointer shaft of a meter having a rotary pointer constructed by utilizing a magnetic fluid having a sealing action and a lubricating action. The present invention relates to a shock absorbing device.

“In the conventional pointer shaft shock absorber for instruments with rotary pointers, the pointer shaft is supported so that it can rotate as a whole while being regulated by a spring at one point. An oil cup is fixedly installed so as to surround the buffer, and the oil cup is filled with buffer solution oil. This buffering oil exhibits a damper effect between the rotating part and the fixed part of the meter due to its viscous action, and has the effect of damping vibrations in the rotating direction of the pointer shaft. As mentioned above, since conventional instruments with rotary pointers contain buffering oil in the device that cushions the pointer shaft, care must be taken to prevent this from leaking outside. Conventional leakage prevention means generally include forming a cap or the like on the oil cup to minimize the opening at the top of the cup. However, even with such measures, it was not possible to completely prevent the buffering oil from flowing out. This is because even if a fluid suitable for buffering oil has a high viscosity, it has a high wettability with respect to the member and may ooze out.

In particular, when the instrument is installed in equipment that vibrates strongly, or when the instrument must be mounted at a certain angle, the possibility of leakage of the buffer oil increases.

This is because when strong vibrations are applied in the axial direction, a pumping action occurs within the oil cup and an inertial action of the buffering oil occurs. Conversely, air may also be drawn in. As a result, the buffering effect of the buffering oil is also impaired. Furthermore, if the temperature at the location where the meter is attached increases, the viscosity of the buffer oil will also decrease, making it even more likely to leak. On the other hand, contact-type leakage prevention means such as oil seals and mechanical tars used in general bearings are not desirable because they generate traction in the bearing and impart hysteresis characteristics to the pointer shaft.

In view of the above-mentioned problems, the inventors have created the present invention to effectively solve the problems.

An object of the present invention is to prevent leakage of the buffering oil to the outside by sealing the buffering oil provided in the support device with a magnetic fluid in a device that buffers the pointer shaft of a meter having a rotary pointer. It is an object of the present invention to provide a shock absorbing device for an instrument pointer shaft which completely prevents the damage.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

In Figure 1, 1 is a partially shown pointer shaft, and pointer shaft 1
An oil cup 2 that rotates together with the pointer shaft is fixed at approximately the center thereof, and a cylindrical body 5 having a bearing part 4 fixed to the fixed frame 3 of the instrument is inside the oil cup 2. It is arranged so as to be inserted into the cylindrical body 5 so that it can be loosely inserted into the cylindrical body 5.

The lower end of the pointer shaft 1 is made into a sharp point and comes into contact with other members with minimal contact resistance so that it can easily rotate.

A pointer is provided at the upper end extending from the father, and the pointer shaft 1
It acts to give a predetermined instruction along with the rotation of. The configuration including only one pointer shaft 11 is omitted in the figure as it is a known fact.

In the structure of the support portion of the pointer shaft 1 shown in FIG.
A magnetic pole 6 is formed near the periphery of the opening of the oil cup 2, and a magnetic pole 7 having a polarity opposite to that of the magnetic pole 6 is formed at 10 locations on the pointer shaft substantially facing the magnetic pole 6. The magnetic pole 6.7 is formed in a ring shape on the periphery of the oil cup 20 and on the pointer shaft 1.

A buffering oil 8 is contained in the oil cup 2, and a magnetic fluid 9 is further filled thereon. Let me briefly explain about magnetic fluid. Magnetic fluids include water, hydrocarbons,
ester,? A colloidal solution in which magnetite with a particle size of about 10 nm is dispersed in a liquid such as ester. A magnetic fluid is a fluid that behaves as if the entire liquid were magnetic when a magnet is brought close to it. Therefore, by placing the magnetic fluid in a magnetic field, it can be placed in a predetermined position.

This makes it possible to exhibit sealing action, lubricating action, viscosity, and the like.

As is clear from the above description, the magnetic fluid 9 disposed between the magnetic poles 6.7 is fixed at that position by the magnetic action of the magnetic poles 6.7, and covers the buffering oil 8 in a liquid state, so that the magnetic fluid 9 is not buffered. The working oil 8 can be completely sealed.

The magnetic fluid 9 is distributed along the lines of magnetic force between the magnetic pole 6 of the oil cup 2 and the magnetic pole 7 of the pointer shaft 1, and even if the magnetic fluid 9 receives a force flowing out from the buffer oil 8, the magnetic fluid 9
returns to its original position by being attracted by the magnetic poles 6.7.

Furthermore, since the magnetic fluid '9 has a lubricating effect, no traction occurs between the rotating part and the fixed part.

In the above embodiment, the magnetic fluid was mainly used as a means for sealing the buffer oil 8, but since the magnetic fluid itself has viscosity and lubricity, it can exert a buffering effect, and as a result, the buffer It is also possible to replace all of the working oil with magnetic fluid.

FIG. 2 shows a second embodiment of the invention. In this embodiment, a cylindrical body 11 made of a magnetic material such as iron and integrated with the cylindrical body 10 is provided at the lower end of a cylindrical body 10 provided on the fixed frame 3. on the other hand.

Two ring-shaped magnetic poles 12 and 13 are formed on the pointer shaft 1 at a constant interval. The polarities of the magnetic poles 12, 13 are different from each other. Further, the portion of the cylindrical body 11 facing the magnetic pole 12.13 is formed to be slightly protruded in order to approach the magnetic pole 12.13. In the above steps, the gap between the magnetic pole 12.13 and the cylindrical body 11 is filled with the magnetic fluid 14.15. magnetic pole 12.1
A magnetic circuit is formed between the magnetic fluid 14, 15, and the cylindrical body 11. In this way, a completely sealed space sealed by the magnetic fluid 14, 15 is formed, and the buffer oil 16 is sealed in this space.

FIG. 3 shows a third embodiment of the invention. In this embodiment, contrary to the second embodiment, a ring-shaped magnet 18 is provided on the inner surface of the cylindrical body 17, and a magnetic portion 19 is provided on the pointer shaft 1 at a position facing the magnet 18. It is something. In this embodiment as well, the magnetic fluid 22, 23 is filled in the magnetic poles 20, 21 of the magnet 18, and the buffer oil 24 is filled in the space between the magnetic fluids 22, 23. be done.

In both the second and third embodiments, a magnetic circuit is formed between the pointer shaft and the cylindrical body, and there is no need to provide a special oil cup. These embodiments have the advantage that they have a simple structure and do not require an oil cup, making it possible to reduce the moment of inertia of the rotating portion, making them suitable for instruments that require high responsiveness.

The pointer shaft shock absorbing device according to the present invention as described above is a shock absorbing device suitable for instruments installed in places where vibration conditions and other usage conditions are severe, such as speedometers mounted on motorcycles. Of course, the present device is not limited to being simply mounted on a motorcycle.

As is clear from the above description, the present invention provides the following effects. Since the buffer oil is sealed with magnetic fluid, leakage of the buffer oil can be completely prevented, and the magnetic fluid can be fixed by attraction using a magnet, which makes the structure simple and reduces the number of parts. becomes. In addition, since the magnetic fluid itself has viscosity and lubricating properties, the pointer shaft rotates smoothly, without interfering with the indicating function of the pointer, and exhibits a pointer shaft rotation function that is greater than that of conventional meters. It is possible to do so.

[Brief explanation of drawings]

The drawings show the present invention -〇-Embodiment, Fig. 1 is a cross-sectional view of the main part of the shock absorber, Fig. 2 is a view similar to Fig. 1 according to the second embodiment, and Fig. 3 is the third embodiment. FIG. 2 is a diagram similar to FIG. 1 according to the example; In the drawing, 1 is a pointer shaft, 2 is an oil cup, 3 is a fixed frame, 4 is a bearing part, 8.16.24 is a buffer oil, 9
．． 14.15.22.23 is magnetic fluid, 6,7.12.
13.20.21 are magnetic poles. Patent applicant Honda Motor Co., Ltd. agent Patent attorney 2 1) Part 1 Patent attorney Kunihiko Ohashi Figure 1 B

Claims (1)

[Claims] In a shock absorber for a pointer shaft of an instrument having a rotary pointer, in which buffer oil is provided between a rotating part including a pointer shaft and a fixed part, the buffer oil is sealed with a magnetic fluid. A shock absorbing device for an instrument pointer shaft, characterized by the following.