JPH054251Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a backlash prevention mechanism for rotary variable resistors used in electronic equipment and the like.

(Prior Art) A rotary variable resistor that has been used conventionally will be explained. First, a first conventional example will be explained.

In FIGS. 5 and 6 of the accompanying drawings, a cylindrical case 1 having a hole 1a at the center of the bottom and an opening 1b at the top includes a protruding head 2a and a protruding head 2a that protrude from the hole 1a. A rotor 2 provided with a slider 4 housed in a groove 2c bored in the axial direction on the bottom surface 2b on the opposite side, a resistor (not shown) on which the slider 4 slides under pressure, and a current collector electrode. A resistor substrate 5 having a body (not shown) printed and fired on the front surface 5a, and a group of output extraction terminals 7 connected to the back surface 5b of the resistor substrate 5 are housed.

Further, the gap formed between the case 1 and the resistor substrate 5 is filled with an adhesive 6, and the adhesive 6 is cured. By curing the adhesive 6, the output extraction terminal group 7 is fixed so as not to move, and the opening 1b of the case 1 is sealed. In other words, the adhesive 6 serves as a base. Instead of the adhesive 6, an insulator formed integrally with the resistor substrate 5 may be used as the base.

As shown in FIG. 6, the rotor 2 is provided with a driver groove 2d for resistance adjustment on the surface of its protruding head 2a, and when housed in the case 1, the stepped portion 2e is The case 1 is rotatably housed in the case 1 in contact with the inner circumferential step 1d of the gap 1.

Reference numeral 3 denotes an elastic O-ring, which is compressed and housed between the rotor 2 and the resistor board 5, and plays the role of complete sealing, so that unnecessary substances such as dust and grease are kept away from the surface 5a of the resistor board 5. This is to prevent intrusion.

Next, the second conventional example will be explained (Utility Model 59
−127216). This conventional example will be explained as follows with reference to the accompanying drawings, FIGS. 7 and 8 (FIGS. 2 and 3 of the same publication). That is, the cap 40 having the operating engagement portion 41 is attached to the volume 17 of the variable resistor housed in the case so as to be rotatable together with the volume 17, while the shoulder of the cap 40 and the operating opening of the cover 30 This electric device is characterized in that an elastic protrusion 44 formed on one of the side walls of the recess 32 formed on the back surface of the recess 31 is pressed against the other side wall. That is, the variable resistor 16 is of a normal type having a volume 17 having a groove 18 projecting from its upper surface, and is covered by the cap 40. As shown in FIG. 8, the cap 40 has a substantially cylindrical shape that completely covers the variable resistor 16, and has a protrusion 4 formed on the ceiling that is an engaging part for operation.
1 engages with the groove 18 of the volume 17 and can rotate together with the volume 17. That is, in this second conventional example, the cap 40 itself and the cover operation opening 31 for operating the variable resistor 16 from the outside are
An elastic protrusion 44 formed on one of the side walls of the recess 32 is pressed against the other to restrict rotation of the cap 40, and as will be described later, the inner wall of the case of the variable resistor 16 itself It is not equipped with a backlash prevention mechanism.

(Problems to be Solved by the Invention) In the rotary variable resistor of the first conventional example, when adjusting the variable resistor to obtain a predetermined setting value, the adjusting driver etc. is inserted into the driver groove 2d. However, as the rotor 2 rotates, the repulsion caused by the displacement of the elastic O-ring 3 compressed and inserted between the rotor 2 and the resistor substrate 5. Immediately after adjustment, a slight rotational return phenomenon occurs in the opposite direction to the rotational direction of the rotor 2 due to the force, so delicate operations are required and time consuming to adjust to the desired setting value. There was a problem.

Hereinafter, the rotation return phenomenon will be referred to as a so-called backlash.

Next, when looking at the electrical equipment of the second conventional example, there are various problems from the viewpoint of prevention of backlash. By operating the engagement groove 43 of the cap 40, the variable resistor 1
When rotating the cap 6, the cap 40 can certainly be prevented from malfunctioning by the elastic protrusion 44. However, due to the rotation of the cap 40,
The operating engagement portion 41 of the cap 40 indirectly rotates the rotor of the variable resistor 16 in a predetermined direction while being engaged with the groove 18 of the variable resistor volume 17. However, the groove 18 of the volume 17
Since there is normally a slight gap between the cap 40 and the operating engaging portion 41 of the cap 40 and between the inner surface of the cap 40 and the volume 17 of the variable resistor 16, there is a gap between the groove 18 and the operating engaging portion 41 of the cap 40. Engagement part 41
When the variable resistor 16 is indirectly rotated together with the cap 40 by the engagement with the variable resistor 16, the slider provided on the lower surface of the rotor housed in the variable resistor 16 slides on the substrate 13. When the rotor is forcibly rotated while moving, there is a risk that the rotor may return or become misaligned due to the above-mentioned gaps, etc., and as a result, it is difficult to improve the setting stability of the variable resistor. This causes various problems, such as requiring a lot of time to set the values.

The present invention aims to solve the problems and obstacles mentioned above, and eliminates the configuration in which the variable resistor is rotated indirectly by operating the cap, and the variable resistor case itself A mechanism is provided to directly prevent backlash.

(Means and effects for solving the problem) In the present invention, the rotor is provided with a slider that slides on the surface of the resistor substrate, and the rotor is rotatably housed in a case. A buck crushing prevention mechanism for a rotary variable resistor is provided, in which an impeller-like fin is provided on the inner wall of a case, and a recess is formed at the root of the fin.

A rotor is housed in a case equipped with the mechanism,
If you apply a screwdriver etc. to the groove of the rotor and rotate the rotor in a predetermined direction, the fin part provided on the inner wall of the case will contact the outer peripheral surface of the rotor and fall in the direction of the recess provided in the root part. , the inner wall of the case and the outer periphery of the rotor come into close contact, resulting in a backlash phenomenon due to the repulsive force caused by the displacement of the O-ring compressed between the rotor and the case. It can be prevented. Further, it is possible to prevent the problems that occur when the variable resistor is indirectly driven by a cap or the like as in the second conventional example, that is, the return phenomenon of the rotor and the phenomenon of positional deviation.

(Example) A buck crash prevention mechanism for a rotary variable resistor according to the present invention will be described below with reference to the accompanying drawings.

1 to 4 of the accompanying drawings, a rotor 2 is housed in a case 8 made of an elastic member such as plastic, and the rotor 2 is inserted through a hole 8a of the case 8.
The first feature is that the protruding portion 2a of the rotor 2 is made to protrude, and the slider 4 is housed in the groove 2c provided in the bottom surface 2b of the rotor 2, and is installed so as to be slidable on the surface 5a of the resistor substrate 5. This is the same as that of the conventional example. In addition, since the configuration other than Case 8, which will be described later, has already been explained in the conventional example, the details thereof will be omitted.

A plurality of fin portions 8e are formed in the shape of an impeller on the inner wall 8c of the case 8, and a recess 8f is provided at the root of each fin portion 8e. The case 8 is optimally made of an elastic body. The recess 8f can also be formed in the shape of a groove as shown in FIGS. 2, 3, and 4. In addition, the code 8b is the case opening, 8
d is the inner peripheral surface of the case.

When the rotor 2 is housed in the case 8, a plurality of fins 8 provided in the shape of an impeller on the inner wall 8c of the case 8
e contacts the outer periphery 2f of the rotor 2 facing the rotor 2, bends in the radial direction under contact pressure, and collapses into the depression 8f formed at its root. Even after falling down,
This fin portion 8e receives contact pressure from the outer circumferential surface 2f of the rotor 2 and maintains a deflected state. In addition, fin part 8
Since e forms a part of the case 8 made of an elastic body, when the rotor 2 rotates, it generates an appropriate torque in the rotational direction between it and the inner surface 8c of the case 8. do.

As pointed out in the problem of the first conventional example, when adjusting the setting value, the elastic O-ring 3 is deformed due to the frictional force generated between the rotating rotor 2 and the elastic O-ring 3. Since the distortion generates a repulsive force that tries to restore the state, immediately after the adjustment, a slight rotational return occurs in the opposite direction to the rotational direction of the rotor 2, and a so-called backlash phenomenon occurs. In such a configuration, the repulsive force caused by the distortion generated between the rotor 2 and the elastic O-ring 3 is absorbed and suppressed, so that the above-mentioned backlash can be prevented from occurring.

Also, compared to the second conventional example, as already pointed out, in this conventional example, the variable resistor is indirectly rotated by rotating a cap separately provided outside the variable resistor. , malfunctions such as variable resistor buckling occur due to rotor return phenomenon and positional deviation.
The mechanism of the present invention prevents such backlash, improves the setting stability of the rotary variable resistor, and shortens the time required to set the set value.

(Effects of the invention) As explained above, according to the invention, the fins, which are provided in the shape of an impeller on the inner surface of the case and have a recess at the root, are pressed against the outer peripheral surface of the rotor, thereby causing the rotor to move. It is possible to prevent the occurrence of backlash during rotation, improve the setting stability of the rotary variable resistor, and shorten the time required to set the set value.

In addition, by setting several locations where contact pressure occurs, the contact pressure per location can be reduced, deformation of the part due to contact pressure can be minimized, and unevenness in torque during rotation can be prevented. It has the following advantages.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a rotary variable resistor incorporating a backlash prevention mechanism according to the present invention. Figure 2 is a plan view of the case. Figure 3 is a side view of the fin. Fourth
The figure is a sectional view taken along the line YY in FIG. 1. FIG. 5 is a sectional view of a rotary variable resistor of a first conventional example. FIG. 6 is a plan view of the rotor shown in FIG. 5. FIG. 7 is a perspective view of a second conventional cap. FIG. 8 is a sectional view showing the relationship among the variable resistor, cap, and cover of the second conventional example shown in FIG. 2... Rotor, 3... Elastic O-ring, 4... Slider, 5... Resistor board, 8... Case, 8c...
...Inner wall of case, 8e...fin section, 8f...indentation.

Claims (1)

[Claims for Utility Model Registration] 1. A backlash prevention mechanism for a rotary variable resistor in which a rotor is provided with a slider that slides on the surface of a resistor substrate, and the rotor is rotatably housed in a case. , a backlash prevention mechanism for a rotary variable resistor in which an impeller-shaped fin is provided on the inner wall of the case, and a recess is formed at the root of the fin. 2. The backlash prevention mechanism for a rotary variable resistor according to claim 1 of the utility model registration claim, wherein the recess at the root of the fin provided on the inner wall of the case is a cut groove formed in the opposite direction to the protruding direction of the fin. . 3. A backlash prevention mechanism for a rotary variable resistor according to claim 1, wherein the case is made of an elastic member.