JPH0376686B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a potentiometer used as a position detection means such as angle or linear displacement, and in particular to a potentiometer that is displaced following external mechanical displacement and whose contact point to a resistance element changes. related to the structure of

Technical Background 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, which 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 the contact point.

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 and its Problems Conventionally, a potentiometer as shown in FIG. 4 has been used. This is the drive shaft 41
Attaching sliders 42 and 43 having an elastic force of
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.

Since the sliders 42 and 43 have elastic force, even if the drive shaft 41 is tilted, the contact points can be changed while reliably contacting the resistive element 45 and the conductive element 46.

However, in this case, there is a problem that the frictional resistance is large and the error becomes large. This is the slider 42,
This is because the contact point 43 slides on the resistive element 45 and the conductive element 46. If the contact force of the contact point is reduced, the frictional resistance will be reduced, but the reliability of the contact point will be lacking.

Technical Problem A technical problem of the present invention is to maintain the contact force of the contacts and reduce the frictional resistance.

Technical means The technical means of the present invention taken to solve the above-mentioned technical problem is to attach a magnet to the drive shaft, arrange a spherical member made of a magnetic and conductive material away from the magnet, and The magnetic material comes into contact with 2
It consists of a real resistance element or a resistance element and a conductor element attached.

Here, the magnet used is one strong enough to ensure that the spherical member contacts the resistive element and the conductive element.

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

The spherical member is a magnetic material and is attracted to the magnet. Due to this attractive force, the spherical member reliably contacts the resistive element and the conductive element, and rolls on the resistive element and the conductive element along with the displacement of the magnet. That is, the spherical member, which is a conductor, becomes a contact point, and the contact point changes as the spherical member rolls, thereby reducing frictional resistance.

Unique effects The present invention produces the following unique effects.

Since the entire spherical surface of the spherical member can be used as a contact point, the life of the contact point is extended.

The drive shaft and the spherical member that is the contact point are mechanically non-contact, so the frictional resistance of the drive shaft does not increase and errors are small.

Since the frictional resistance is small, the followability of the contact point is improved, hysteresis is small, and resolution is improved.

DESCRIPTION OF EMBODIMENTS An embodiment illustrating a specific example of the above technical means will be described (see FIG. 1).

This is a rotary potentiometer, and a drive shaft 2 is attached to the casing 1 to rotate following external mechanical displacement. Casing 1 and drive shaft 2
Bearings 3 and 4 are interposed between them. A magnet 5 is attached to the drive shaft 2 via a mounting shaft 11. An annular protruding part 6 extending to the upper surface of the magnet 5 is formed on the casing 1, and a minute gap is provided between the protruding part 6 and the magnet 5. The protruding portion 6 is formed of a non-magnetic insulator. A V-shaped annular groove 7 is formed on the upper surface of the protruding portion 6. A spherical member 8 made of a magnetic material and a conductor is placed in the groove 7 . An annular resistance element 9 and a conductive element 10 are attached to the inner surface of the groove 7 so as to face each other over the movement range of the magnet 5. An input terminal (not shown) and a ground terminal (not shown) are attached to both ends of the resistive element 9, and an output terminal (not shown) is attached to one end of the conductive element 10, facing the input terminal. A voltage is applied between both terminals of the resistive element 9, and a voltage between the input terminal and the output terminal is extracted.

In this embodiment, since the resistive element 9 and the conductive element 10 are attached to the V-shaped annular groove 7 facing each other, the spherical member 8 is attracted by the magnet 5 and the resistive element 9 and the conductive element 10 are reliably attached. It can touch two points, making it easy to position the contacts.

Another embodiment will be described (see FIGS. 2 and 3).

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 spherical member 26 made of a magnetic and conductive material is placed in the other chamber. On the side of the partition wall 22 where the spherical member 26 is arranged, there is a V across the movement range of the magnet.
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. Counter 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 sectional view of an embodiment of the potentiometer of the present invention, FIG. 2 is a sectional view of another embodiment, FIG. 3 is a sectional view taken along the - line in FIG. 2, and FIG. 4 is a sectional view of a conventional potentiometer. It is a sectional view of a meter. 2, 23... Drive shaft, 5, 24... Magnet, 7,
27... Annular groove, 8, 26... Spherical member, 9,
28, 29...Resistance element, 10...Conductor element.

Claims (1)

[Claims] 1 A magnet is attached to the drive shaft, a spherical member made of magnetic material and a conductor is placed apart from the magnet, and two resistive elements or a resistive element and a conductive element are attached to which the spherical member contacts over the movement range of the magnet. potentiometer.