JPS6244491Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to variable resistors, and in particular focuses on reducing the number of parts and solving processing problems in small variable resistors equipped with adjustment shafts with driver adjustment grooves. Regarding variable resistors.

1 to 3 show a first conventional example, in which FIG. 1 is a plan view, FIG. 2 is a central sectional view, and FIG. 3 is a perspective view of the adjustment shaft seen from below.

The first conventional example shown here is basically composed of four parts: a substrate 1, an adjustment shaft 2, a wiper 3, and a spacer 4. After a shaft portion 5 of the adjustment shaft 2 is inserted into a hole 6 provided in the substrate 1, its lower end is crimped, so that the adjustment shaft 2 is held rotatably relative to the substrate 1. Although not shown, a resistive film is formed in a C-shape on the upper surface of the substrate 1. At the lower portion of the head portion 7 of the adjustment shaft 2,
A step 8 is formed, and a flat surface 9 is formed on this step 8. The wiper 3 has a hole that receives the step 8 of the adjustment shaft 2, and this hole has the same contour as the cross-sectional shape of the step 8. Therefore, the flat surface 9 acts to rotate the wiper 3 integrally with the adjustment shaft 2. A driver adjustment groove 11 is formed on the upper surface of the head 7 of the adjustment shaft 2, and by fitting the tip of a screwdriver or the like into this groove and rotating the adjustment shaft 2, the wiper 3 also rotates integrally, and the contact portion 10 of the wiper 3 slides while contacting the aforementioned resistive film, thereby adjusting the resistance value obtained by this variable resistor.

The wiper 3 described above is made of a metal material having spring properties, and this spring property allows the contact portion 10 to
In order for the wiper 3 to contact the resistive film with a constant pressure, the root portion 12 of the wiper 3 must be supported at a constant distance from the upper surface of the substrate 1. For this purpose, a spacer 4 is used, which connects the substrate 1 and the root portion 12 of the wiper 3.
It can be placed between. However, this spacer 4 is undesirable because it increases the number of parts for constructing such a variable resistor.

As a structure without the spacer mentioned above,
A second conventional example shown in FIGS. 4 and 5 has been proposed. FIG. 4 is a perspective view of the wiper from above, and FIG. 5 is a perspective view of the adjustment shaft from below.

As shown in FIG. 4, a concave portion 14 having a non-circular shape, such as a triangular or square shape, is formed by drawing at the base portion of the wiper 13, and a hole 15 is provided within this concave portion 14. On the other hand, as shown in FIG.
A convex portion 19 having a shape corresponding to the above-mentioned concave portion 14, that is, triangular in the illustrated conventional example, is provided at the boundary between the head portion 18 and the concave portion 14.

In a variable resistor including such a wiper 13 and an adjustment shaft 16, in the assembled state, the shaft portion 17 of the adjustment shaft 16 is aligned with the hole 1 of the wiper 13.
5 and the convex portion 19 fits into the concave portion 14 , the wiper 13 rotates together with the adjustment shaft 16 . The height dimension of the recess 14 serves as the spacer 4 of the first conventional example described above, and a structure that does not require a spacer is realized.

However, in this second conventional example, the recess 1
4 is formed by drawing, so it is relatively difficult to achieve dimensional accuracy. If the concave portion 14 is formed larger than the set value, play will occur when the convex portion 19 is received, and the adjustment shaft 16
The wiper 13 will not be able to properly follow the rotation of. A more important problem is that in such a case, the contact area between the adjustment shaft 16 and the wiper 13 becomes small, so the wiper 13 may tilt undesirably during the rotation of the adjustment shaft 16 or after the adjustment operation. This causes a change in the resistance value to be adjusted, which is a fatal defect especially in semi-fixed resistors. On the other hand, if the recess 14 were formed smaller than the set value, it would be impossible to receive the protrusion 19.

Therefore, the main objective of the present invention is to provide a variable resistor structure that can advantageously overcome the problems of the prior art as described above.

In summary, this idea consists of forming a stepped portion on the head of the adjustment shaft, forming a circular portion for receiving the stepped portion and a vertical wall portion on the wiper, and placing the circular portion in contact with the substrate. First, the wiper is stably held on the adjustment shaft, and the step of the adjustment shaft is provided with a protrusion that protrudes laterally, and the vertical wall of the wiper is provided with a protrusion that protrudes laterally. The variable resistor is configured to form an opening such as a hole or notch for receiving a protrusion so that the wiper rotates together with the adjustment shaft.

Other objects and features of this invention will become clearer from the detailed description given below with reference to the drawings.

FIG. 6 is a central sectional view of an embodiment of this invention. FIG. 7 is a perspective view of the wiper of FIG. 6, viewed from above. FIG. 8 is a perspective view of the adjustment shaft shown in FIG. 6, viewed from below. FIG. 9 is a perspective view of the adjustment shaft shown in FIG. 6, viewed from above.

This embodiment basically consists of three parts: a substrate 20, an adjustment shaft 21, and a wiper 22. The substrate 20 is provided with a hole 24 that receives the shaft portion 23 of the adjustment shaft 21, and after the shaft portion 23 is inserted into the hole 24, the lower end of the shaft portion 23 is caulked, so that the adjustment shaft 21 is fixed. It is rotatably held relative to the substrate 20. A resistive film 25 is formed on the upper surface of the substrate 20.
is formed in a C-shape. Terminals (not shown) are connected to both ends of this resistive film 25, respectively. The wiper 22 is made of a metal material having appropriate spring properties, and its contact portion 26 contacts the resistive film 25. The wiper 22 is also configured to contact a lead-out conductor 27 formed on the substrate 20, and a terminal (not shown) is also connected to this lead-out conductor 27. A driver adjustment groove 29 is provided on the upper surface of the head 28 of the adjustment shaft 21 . Below, while referring to the configuration that is the feature of this example,
The details of each part will be explained.

The wiper 22 has a circular portion 30 that contacts the substrate 20, more precisely, the lead-out conductor 27, and a vertical wall portion 31 rising from the outer periphery of the circular portion 30. The aforementioned contact portion 26 is formed extending from the upper end of this vertical wall portion 31 . A hole 32 for receiving the shaft portion 23 of the adjustment shaft 21 is formed at the center of the circular portion 30 . In this way, first, a certain space is defined by the circular portion 30 and the vertical wall portion 31.

The head 28 of the adjustment shaft 21 has the above-mentioned circular portion 3.
A step 33 is provided which is received within the space defined by the vertical wall 31 and the vertical wall 31 . This step 3
3 contacts the circular portion 30 of the wiper 22, so that the circular portion 30 of the wiper 22 is sandwiched between the base plate 20 and the adjustment shaft 21. Therefore, positioning of the wiper 22 in the inclination direction with respect to the adjustment shaft 21 is reliably achieved.

A hole 34 serving as an opening is formed in the vertical wall portion 31 of the wiper 22 . In the illustrated embodiment, the hole 34 is provided extending from the vertical wall portion 31 to a horizontal wall portion 35 on the outer periphery of the wiper 22 . The distance that the hole 34 extends in the horizontal wall portion 35 is arbitrary, and the hole 34 may be formed substantially only in the vertical wall portion 31. Conversely, the hole 34 may extend to the outer peripheral edge of the horizontal wall portion 35 and may be formed as a notch instead of a hole. On the other hand, the stepped portion 33 of the adjustment shaft 21 is provided with a protrusion 36 that protrudes laterally. This protrusion 36 is to be received within the hole 34 described above. In this way, a configuration is realized in which the protrusion 36 engages within the hole 34 and the wiper 22 rotates together with the adjustment shaft 21.

FIG. 10 is a front view of the adjustment shaft of another embodiment of this invention. The adjustment shaft 21 shown here is attached to the protrusion 3
6 and the shape of the shaft portion 23 are distinctive. That is, the protrusion 36 is tapered on both sides, and the upper part of the shaft portion 23 is also tapered.
These tapers are shaped to widen upward. According to the projection 36 and the shaft portion 23 having such a shape, when the projection 36 and the shaft portion 23 are fitted into the holes 34 and 32, the taper acts advantageously, and the projection 36 and the shaft portion 23 are tightly fitted into the holes 34 and 32. make it possible. This prevents play between the rotation of the adjustment shaft 21 and the rotation of the wiper 22, and also absorbs dimensional errors between the holes 34 and 32, the protrusion 36, and the shaft portion 23. There is also the advantage of doing so. Furthermore, for example, it is possible to temporarily fix the wiper 22 to the adjustment shaft 21 before inserting the adjustment shaft 21 into the hole 24 of the substrate 20. That is, the protrusion 36 and the shaft portion 2
By using the taper No. 3, it becomes possible to make the protrusion 36 and the shaft portion 23 bite into the holes 34 and 32, respectively, and thereby the wiper 22
can be handled integrally with the adjustment shaft 21 in the assembly process, which in a sense has the same meaning as reducing the number of parts.

As described above, according to this invention, the wiper has a circular part and a vertical wall part, and while this circular part is in contact with the substrate, the stepped part of the adjustment shaft is moved by the circular part and the vertical wall part. Since the wiper is received within the defined space, the wiper is stably held. Therefore, fluctuations in the adjusted resistance value are prevented. In addition, in order to allow the wiper to rotate together with the adjustment shaft, an engagement means consisting of a protrusion and an opening for receiving the protrusion is applied, and the opening constituting one of the engagement means is formed by punching a metal plate. It can thus be formed with high precision in its dimensions and position, and therefore no play in rotation occurs. Furthermore, since the contact portion of the wiper is provided extending from the upper end of the vertical wall portion, extra parts such as spacers are not required.

[Brief explanation of the drawing]

1 to 3 show a first conventional example, in which FIG. 1 is a plan view, FIG. 2 is a central sectional view, and FIG. 3 is a perspective view of the adjustment shaft seen from below. FIGS. 4 and 5 show the main parts of the second conventional example. FIG. 4 is a perspective view of the wiper from above, and FIG. 5 is a perspective view of the adjustment shaft from below. FIG. 6 is a central sectional view of an embodiment of this invention. Figure 7 is the 6th
FIG. 2 is a perspective view of the wiper shown in the figure from above. 8th
This figure is a perspective view showing the adjustment shaft of FIG. 6 from below. FIG. 9 is a perspective view of the adjustment shaft shown in FIG. 6, viewed from above. FIG. 10 is a front view of the adjustment shaft of another embodiment of this invention. In the figure, 20 is a substrate, 21 is an adjustment shaft, 22
is a wiper, 23 is a shaft portion, 24 is a hole, 25 is a resistive film, 26 is a contact portion, 28 is a head portion, 30 is a circular portion, 31 is a vertical wall portion, 32 is a hole, 33 is a step portion, 3
4 is a hole as an opening, and 36 is a protrusion.

Claims (1)

[Claim for Utility Model Registration] A board, an adjustment shaft, and a wiper are provided, and the adjustment shaft is rotatably held relative to the board with the shaft portion of the adjustment shaft inserted into a hole provided in the board. A resistive film is formed in a C-shape, and the adjusting shaft and the wiper are rotated together by engaging means that engage with each other when the wiper receives the shaft portion of the adjusting shaft. In a variable resistor in which a contact portion of the wiper slides while being in contact with a resistive film in response to rotation, the wiper has a circular portion that contacts the substrate and a vertical wall portion rising from the outer periphery of the circular portion. , the contact portion extends from an upper end of the vertical wall portion, and the head of the adjustment shaft contacts the circular portion and is received in a space defined by the circular portion and the vertical wall portion. A variable resistor, wherein the engaging means includes a protrusion projecting laterally from the step part, and an opening formed in the vertical wall part and receiving the protrusion.