JPH06109592A - Evaluating method for spiral spring - Google Patents

Abstract

PURPOSE:To evaluate a spiral spring with high reproducibility by inserting the spring into a truncated conical jig, and measuring a spring constant of the spring. CONSTITUTION:A jig 10 has a truncated conical state having an upper side smaller than an inner diameter of a spiral spring 7, a lower side larger than the inner diameter of the spring 7, and a scale 11 provided on its body. The inner peripheral part of the spring 7 is inserted from above the jig 10, and a force is applied down. Thus, the spring 7 is radially extended by the jig, moved down and stopped at a suitable position. An end B of the spring 7 at the stopped position is read by the scale 11, converted to a spring constant, thereby measuring the constant. In order to apply a downward force to the spring 7, a method in which own weight of the spring 7 is used, the spring is dropped from a certain height, or a doughnut-like weight is placed from above the spring 7, is used. Since an operation for gripping the spring is not required, the spring is not damaged, and reproducibility is high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating a spiral spring used in a movable iron piece type instrument or a movable coil type instrument.

[0002]

2. Description of the Prior Art Before explaining the present invention, a movable iron piece type instrument in which a spiral spring is used for evaluation will be described with reference to FIG. In the figure, 1 is a field coil wound in an annular shape, 2 is a fixed iron piece attached inside the field coil 1, and 3 is a movable iron piece. 4 is a movable part, a rotary shaft 5 and a pointer 6 attached to this rotary shaft,
It is composed of the spiral spring 7 and the movable iron piece 3 described above. In the movable iron piece type instrument having such a configuration, when current is supplied to the field coil 1, the two iron pieces 2 and 3 are magnetized, and a repulsive force is generated between the two iron pieces. This repulsive force becomes a rotational torque, and the pointer 6 rotates about the rotating shaft 5 up to an angle θ that balances the restoring force of the spiral spring 7, and the instruction is determined. Although such a movable iron piece type instrument has been used conventionally,
Since the spiral spring 7 has a small torque, it cannot be manufactured with a constant plate thickness and width, and the restoring force varies. This appears as a variation in the indicated angle θ, that is, a noticeable (indicated value) error of an amount that cannot be ignored. Therefore, when manufacturing a measuring instrument, it is necessary to measure the spring constant (or torque) of the spiral spring 7 before assembling the measuring instrument. Although a movable iron piece type instrument is illustrated in the figure, a spiral spring is also used for the movable coil type instrument, but it is necessary to evaluate similarly in this case as well.

A plan view of the spiral spring 7 is shown in FIG. 3. Conventionally, in the case of evaluating the spring constant of such a spiral spring, both the inner side A and the outer side B of the spiral spring 7 are grasped to rotate around the center of rotation. In addition, the spring constant was measured by twisting this spiral spring. However, such an evaluation method has the following drawbacks. That is, since the spiral spring 7 is usually as small as about Φ10 mm, it is difficult to grip A and B. Therefore, it is not suitable when a large number of samples need to be evaluated in a relatively short time, such as an acceptance inspection. Reproducibility is poor. That is, it is necessary to grasp the spiral spring 7 without giving an extra force, but it is difficult to evaluate it with good reproducibility because it is grasped obliquely or eccentric. In addition, the spring may be deformed.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to evaluate the spring constant (or torque) without the conventional work of gripping a spiral spring, so that the sample can be quickly and quickly scratched.
In addition, the quality of the spring can be selected with good reproducibility.

[0005]

[Means for Solving the Problem] A spiral spring to be evaluated is inserted through a graduated cone-shaped jig, and the spring constant of the spiral spring is measured from the tip position of the spiral spring in a stationary state. It consists of means.

[0006]

According to the present invention as described above, by inserting the spiral spring into the jig, the tip position in a stationary state varies depending on the torque of the spiral spring.

[0007]

The present invention will be described below with reference to the drawings. FIG. 1 shows a jig relating to the evaluation method of the present invention. In the figure, 10 is the jig, and 7 is a spiral spring to be evaluated. The jig 10 has a conical shape in which the upper side is smaller than the inner diameter of the spiral spring 7 and the lower side is larger than the inner diameter of the spiral spring 7, and a scale 11 is provided on its body.
In order to evaluate the spiral spring 7 using the jig 10 having such a structure, the inner diameter portion of the spiral spring 7 is inserted into the jig 10 from above the jig 10 and a downward force is applied in the drawing. To do. Then, the spiral spring 7 spreads in the radial direction by the jig 10, moves downward, and stops at an appropriate position. The tip (part B) of the spring 7 at this stationary position is read by the scale 11 and converted into a spring constant, whereby the spring constant (or torque) is measured. In this case, in order to apply a downward force to the spiral spring 7, there is a method of using the weight of the spring 7, dropping it from a certain height, or placing a donut-shaped weight on the spring 7. To read the spiral spring 7 at a stationary position, there is a method of detecting with light, in addition to using the scale 11 as shown in FIG.

[0008]

As described above, according to the spiral spring evaluation method of the present invention, the spring is not damaged because an operation such as gripping the spring is not required unlike the conventional method, and the spring has good reproducibility. It has the feature that the spring constant can be measured quickly and in a short time. Such a spiral spring evaluation method according to the present invention enables on-line evaluation on site, and its practical effect is extremely large.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an example of a jig used in an evaluation method of the present invention.

FIG. 2 is a configuration diagram of an example of an instrument in which a spiral spring is used.

FIG. 3 is a configuration diagram of a spiral spring.

[Explanation of symbols]

 7 Swirl spring 10 Jig 11 Scale

Claims (1)

[Claims] 1. A calibrated cone-shaped jig is provided, and the spring constant of the spiral spring is calculated from the tip position of the spiral spring in a stationary state by inserting the spiral spring evaluated in the jig. Evaluation method for spiral springs that is designed to be measured.