JPH0414884Y2 - - Google Patents

Description

[Detailed explanation of the invention] (1) Purpose of the invention [Field of industrial application] The present invention relates to the structure of a variable resistor, and in particular, it is possible to restore the normal state by a simple operation when the brush comes off accidentally during assembly. It relates to a structure that can be restored to the original state.

[Prior Art] The structure of a variable resistor according to the prior art will be explained with reference to FIG.

FIG. 1a is a sectional view showing the structure of a conventional variable resistor, in which an annular resistor 8 is fixed inside a casing 1 made of an opaque material. A rear cover 2 fitted to the open end of the housing 1
A rotating shaft 4 rotatably supported by a bearing 3 mounted at the center of each, and a current collecting ring 6 disposed on the rotating shaft 4 via a hub 5 formed of an insulator.
An arm 7-1 holding a sliding contact 7 is fixed to the end face of the current collecting ring 6 facing the annular resistor 8, and the tip of the sliding contact 7 is attached to the annular resistor 8. 8 to bring it into sliding contact with the surface thereof with an appropriate pressure.

A shallow groove 6-1 is provided on the outer periphery of the current collecting ring 6, and a plurality of linear brushes 9 fixed to terminals 10 provided insulated on the outer periphery of the housing are brought into contact with the outer periphery of the current collecting ring 6. The shallow groove 6-1 prevents the brush 9 from coming off during normal operation.

The variable resistor shown in FIG. 3a connects both ends of an annular resistor 8 to other terminals (not shown) provided on the outer periphery of the housing, and the sliding contacts are connected by rotation of the rotating shaft 4. By changing the contact position between the resistor 7 and the resistor 8, the resistance value between the terminal connecting both ends of the resistor 8 and the terminal 10 to which the brush 9 is fixed can be changed, or the resistance value can be converted into voltage and applied to the rotating shaft 4. The device performs functions such as electrically detecting the position of the object.

Therefore, in a mechanism in which two electrical contact members such as the sliding contact 7 or the brush 9 maintain contact while moving with respect to each other, one of the members is formed of a plurality of contact members in order to maintain stable contact. However, it is designed to ensure stable contact over a long period of time.

FIG. 3b shows the arm 7-1 holding the current collecting ring 6, the brushes 9, 9, and the sliding contact 7 fixed to the current collecting ring 6, when the cross-sectional view shown in FIG. 3a is viewed from the direction of the arrow. This is a perspective view of the main parts showing the relationship between the two, and the casing 1, resistor 8, etc. are omitted to avoid complication.

As an example of using a plurality of contact members, as shown in figure b, a current collecting ring 6 is fixed to the outer periphery of a hub 5 fixed to the rotating shaft 4, and is fixed to a terminal 10 provided insulated on the outer periphery of the casing. two elastic brushes 9,
9 are opened in a V-shape at the base of the terminal 10 and brought into contact with the outer periphery of the current collecting ring 6, respectively.

By providing two brushes 9 in this way, even if one of the brushes has poor contact, as long as the remaining one maintains good contact, it can operate normally, thus prolonging the life. be able to.

[Problems to be solved by the invention] The following steps are used to assemble the variable resistor shown in FIGS. 3a and 3b.

An annular resistor 8 is fixed inside the casing 1, and two brushes 9, 9 are fixed to the terminal 10 by opening them in a V-shape at an appropriate angle. The movable end of the rotating shaft 4 is provided in the housing 1, to which the current collecting ring 6 is fixed and the arm 7-1 for holding the sliding contact 7 is fixed to the end face of the current collecting ring 6 facing the resistor 8. The sliding contact 7 is brought into contact with the surface of the resistor 8, and the two V-shaped brushes 9 are opened wider than the outer diameter of the current collector ring 6 using a jig or the like. Insert the rotating shaft 4 into the bearing 3 until the current collecting ring 6 is approximately aligned with the position of the brushes 9, 9, and after making it contact the stop ring, remove the jig and remove the two brushes 9, 9. Its elasticity brings it into contact with the outer periphery of the current collector ring 6, and the rear cover 2 is fitted to complete the assembly.

At this time, it is important that the two brushes 9, 9 securely sandwich and contact the current collecting ring 6 in a V-shape.
The openings of the two brushes 9 and 9 are not parallel, and the openings are mistakenly 1.
The rear cover 2 may be fitted and the assembly completed with the book brush 9' removed from the outer periphery of the current collector ring 6 onto the hub 5. This state is shown in the partial sectional view a in FIG. This is shown in front view b.

In this state, since the housing is made of an opaque material, it cannot be visually confirmed from the outside after the rear cover 2 is fitted.

Electrically, the resistance value between each terminal can be confirmed by testing and inspecting by rotating the rotary shaft 4, but if one of the brushes 9' is connected to the current collecting ring 6 as shown in FIG. Even though the brush 9' has come off from the outer periphery of the hub 5, since the other brush 9 is in contact with the current collecting ring 6, it is judged to be normal in the electrical test, and it is discovered that the brush 9' has come off. It ends up being shipped without being able to do it.

Even in this state, no abnormality occurs in the initial operating state, but if one brush that is in contact with the current collection ring becomes abnormal due to long-term use, two brushes are installed for the purpose of long-term stable contact. However, it can shorten the lifespan.

On the other hand, if the brush 9 comes off not in the direction of the hub 5 but in the direction of the arm 7-1 holding the sliding contact 7, when the rotating shaft 4 is rotated, the arm 7-1 and the sliding contact 7 If the brush 9 comes into contact with the brush 9 and can be easily detected due to an abnormal feel and sound, or if the brush 9' is rotated in the opposite direction, the arm 7-1 and the sliding contact 7 return the detached brush 9' to the outer periphery of the current collecting ring 6. In some cases, the discovery of abnormalities,
Alternatively, the normal brush contact state may be restored.

The purpose of this invention is to remove the detached brush to the outer periphery of the current collector ring with a simple operation when one of the brushes comes off toward the hub and no mechanical or electrical abnormality can be detected. The objective is to obtain a variable resistor that can be returned to normal contact state.

(2) Structure of the invention [Means for solving the problem] The variable resistor according to the invention has a current collector ring that slides on the outer periphery of a hub 5 formed of an insulating member provided on the outer periphery of a rotating shaft 4. Contact with the end surface opposite to the end surface provided with the arm that holds the contact, its cross-sectional shape is trapezoid, the outer diameter of the upper end of the trapezoid is larger than the outer diameter of the current collecting ring, and the slope increases as it moves away from the current collecting ring. The problem is solved by a structure in which one or more protrusions are provided, and the brushes that have come off from the outer periphery of the current collecting ring in the direction of the hub can be returned to the outer periphery of the current collecting ring.

[Function] In the variable resistor of the present invention, the rotating shaft is rotated and the brush, which is deviated in the direction of the hub, is placed on the trapezoidal protrusion provided on the outer periphery of the hub, and current is collected along the slope of the protrusion. The brush is dropped on the outer periphery of the ring and returned to the outer periphery of the current collecting ring, and the brush that has come off during one revolution of the rotating shaft can be reliably returned to its original position.

[Example] Fig. 1 is a partial side view a showing the main parts of the structure of the variable resistor according to the present invention, and a partial front view b when Fig. a is viewed from the direction of the arrow. The hub 5, the current collecting ring 6, the trapezoidal protrusion 5-2 provided on the outer periphery of the hub 5, a plurality of brushes 9, 9' arranged so as to be in contact with the current collecting ring, and a terminal for fixing the brushes 9, 9'. 10
Only shown.

In FIG. 1, a hub 5 provided on the outer periphery of the rotating shaft 4
is in contact with the end surface of the current collecting ring 6 at its outer periphery, its cross-sectional shape is trapezoidal, and the outer diameter of the upper end 5-1 of the trapezoid is larger than the outer diameter of the current collecting ring 6, and as it becomes farther away from the current collecting ring in the axial direction. It is characterized by a structure in which one or more protrusions 5-2 are provided with a slope in which the outer diameter increases.

Figures 1a and 1b show a state in which one brush 9' has come off in the direction of the hub 5, in figure a the detached brush 9' is hanging on the side of the hub 5, and in figure b a partial front view shows the detached brush 9'. 9' is shown riding on the outer periphery of the hub 5 at a position in front of the current collecting ring 6.

When the rotating shaft 4 is rotated clockwise in the state shown in FIG. When it is rotated, it is lifted to a position exceeding the outer diameter of the current collecting ring 6, and when it is further rotated, it is naturally returned to the outer periphery of the current collecting ring that has been dropped onto the outer periphery of the current collecting ring 6 along the slope provided at the upper end 5-1. .

At this time, the rotating shaft can be rotated in any direction; if it is rotated counterclockwise,
The protrusion 5-2 rotates without contacting the brush 9 in its normal position, and when it reaches the position of the detached brush 9', the detached brush 9' is lifted by the upper end 5-1 of the trapezoidal protrusion 5-2. The brushes are dropped onto the outer periphery of the current collecting ring 6 along the slope of the upper end and are naturally returned to the outer periphery of the current collecting ring, resulting in the normal brush contact state shown in FIGS. 2a and 2b. Trapezoidal projection 5-
2 no longer has any relationship with the brushes 9, 9.

This return operation only requires one rotation of the rotating shaft. After fitting the rear cover in the assembly process, by adding an operation of rotating the rotating shaft once before and after the electrical test, it is possible to remove the brushes that have come off. ′ can be restored to its normal state, even if it is used in all assembly processes and includes the operation of discovering when the brush has come off in the direction in which the arm is attached, the increase in man-hours is minimal.
A highly reliable variable resistor can be obtained.

[Effect of the invention] Since the variable resistor of the invention has the above-mentioned configuration, even if the brush accidentally comes off the outer periphery of the current collector ring during assembly, it will not rotate after assembly is completed. With a simple rotation of the shaft, the detached brush can be returned to the outer periphery of the current collection ring, resulting in a highly reliable variable resistor.

[Brief explanation of the drawing]

Fig. 1 is a partial side view a and a partial front view b showing the structure of the variable resistor according to the present invention, and Fig. 2 is an explanatory diagram of the main part of Fig. 1 according to the present invention in a state where it has returned to its normal state. Figure 3 is a cross-sectional view a and a perspective view of the main part b showing the structure of a conventional variable resistor, and Figure 4 is a conventional variable resistor in which one of the brushes has come off in the direction of the hub. FIG. 2 is a partial cross-sectional view a and a perspective view b of a main part, showing a state in which the Explanation of symbols, 1... Housing, 2... Rear cover, 3...
Bearing, 4... Rotating shaft, 5... Hub, 6... Current collecting ring, 6-1... Current collecting ring groove, 7... Sliding contact, 7
-1...Arm that holds the sliding contact, 8...Resistor,
9...Brush, 9'...Brush in a detached state, 1
0...Terminal.

Claims (1)

[Scope of utility model registration request] At least a housing, an annular resistor fixed inside the housing, a rotating shaft rotatably supported by a bearing provided in the housing, and a hub formed of an insulator on the rotating shaft. A sliding contact provided at the tip of an arm fixed to the end face opposite to the annular resistor of the current collecting ring fixed to the ring is brought into sliding contact with the resistor,
and a variable resistor having a structure in which a plurality of brushes fixed to terminals provided insulated on the outer periphery of the housing are brought into contact with the outer periphery of the current collecting ring, and an arm of the current collecting ring is provided on the outer periphery of the hub. At a position in contact with the end surface opposite to the end surface, a piece having a trapezoidal cross-sectional shape, the upper end of the trapezoid having a larger outer diameter than the outer diameter of the current collecting ring, and having a slope such that the outer diameter increases as it leaves the end surface of the current collecting ring. Or a variable resistor characterized by being provided with a plurality of protrusions.