JPH0239842B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a potentiometer used as a means for detecting position such as angle or linear displacement, and particularly to a potentiometer that is displaced in accordance with external mechanical displacement and that connects a contact point to a resistive element. It concerns the structure of the parts that change.

A potentiometer transmits an external mechanical displacement to a drive shaft, and the rotational or linear displacement motion of that shaft causes the contacts of a slider attached to that shaft to slide over a resistive element, causing the contacts to this resistive element to slide over a resistive element. The amount of electrical displacement corresponding to the amount of mechanical displacement is detected by the change in resistance value due to the change in .

Therefore, in such a potentiometer, it is necessary that the contacts of the slider reliably come into contact with the resistance element, and that the contacts change in accordance with external mechanical displacement.

Prior Art Therefore, in the past, a potentiometer as shown in FIG. 3 was used. This is the drive shaft 41
Sliders 42 and 43 having elastic force are attached to the
Contact points of sliders 42 and 43 are configured to slide on a resistance element 45 and a conductor element 46 attached to the inner surface of a casing 44. In addition, reference number 47 is a bearing, 48 is a spring, and 49, 50, and 51 are terminals.

Applying voltage between terminals 49 and 50, terminal 4
The voltage between 9 and 51 is taken out as an output.

That is, due to external mechanical displacement, the drive shaft 41
is linearly displaced, and the contact points of the sliders 42 and 43 attached to the drive shaft 41 are connected to the resistive element 45 and the conductive element 4.
6, and the voltage is detected by the change in resistance value due to the change in the contact point to the resistance element 45 corresponding to the amount of mechanical displacement.

Problems to be Solved by the Present Invention In the above-mentioned sliders, since the sliders 42 and 43 slide on the resistive element 45 and the conductive element 46, there is a problem that wear occurs and the service life is short.

Means for Solving the Problems The technical means of the present invention taken to solve the above technical problems is to divide the inside of the casing into two chambers with a partition wall, and place a magnet attached to a drive shaft in one chamber. A magnetic fluid containing conductive particles is placed in the other chamber, and the two resistive elements or the resistive element and the conductive element in contact with the magnetic fluid are attached to the partition wall member in the other chamber over the movement range of the magnet. It is something that has been installed.

Here, as the conductive fine particles, for example, carbon particles or metal particles are used. As the solvent for the magnetic fluid, for example, diester, fluorocarbon, etc. are used. This magnetic fluid containing electrically conductive particles has fairly high electrical conductivity. Further, the magnet used is strong enough to ensure that the magnetic fluid containing the conductive particles comes into contact with the resistive element and the conductive element.

Effect The operation of the above technical means is as follows.

A magnetic fluid containing conductive fine particles has high electrical conductivity and is attracted to a magnet. This attractive force allows the magnetic fluid to reliably contact the resistive element and the conductive element, and to flow over the resistive element and the conductive element as the magnet is displaced. In this way, the magnetic fluid serves as a contact point, and the contact changes as the magnetic fluid flows, so that there is no wear on the magnetic fluid that serves as a contact point.

Effect of the invention The present invention produces the following unique effects.

As described above, according to the present invention, since there is no wear of the contacts, the desired good operation can be maintained for a long period of time.

Embodiment An embodiment illustrating a specific example of the above technical means will be described (see FIG. 1 and FIG. 2).

This is a reciprocating potentiometer, and the casing 21 is a non-magnetic material with a thin insulating partition wall 22.
It is divided into two rooms. A drive shaft 23 is attached to one of the chambers for linear displacement following external mechanical displacement. A magnet 24 is attached to the tip of the drive shaft 23. A bearing 25 is interposed between the drive shaft 23 and the casing 21. A magnetic fluid 26 containing conductive particles is placed in the other chamber. Fluid 2 in partition wall 22
On the side where 6 is placed, there is a V across the movement range of the magnet 24.
A letter-shaped groove 27 is provided. Resistance elements 28 and 29 are attached to the inner surface of the groove 27. An input terminal (not shown) and a ground terminal (not shown) are connected to both ends of the resistive element 28.
An output terminal (not shown) is attached to one end of the resistive element 29, facing the input terminal. Resistance element 28
Apply voltage between the terminals and extract the voltage between the input and output terminals.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the potentiometer of the present invention, FIG. 2 is a cross-sectional view taken along the - line in FIG.
The figure is a cross-sectional view of a conventional potentiometer. 23... Drive shaft, 24... Magnet, 28, 29...
...resistance element, 26...magnetic fluid.

Claims (1)

[Claims] 1 The inside of the casing is divided into two chambers by a partition wall, a magnet attached to a drive shaft is placed in one chamber, a magnetic fluid containing conductive particles is placed in the other chamber, and two chambers are placed in contact with the magnetic fluid. A potentiometer in which a resistive element or a resistive element and a conductive element are attached to a partition wall member in the other room over the movement range of the magnet.