JP2967600B2 - coil spring - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil spring, and more particularly to an elliptical coil spring suitable for automatic assembly.

[0002]

2. Description of the Related Art Generally, a coil spring is installed inside a product such as a machine or an instrument by an automatic assembling apparatus such as a transfer line.
2. Description of the Related Art There has been known an apparatus which supplies an elliptical coil spring by a component feeder of a vibration conveyance system. The specifications of the elliptical coil spring conveyed by such a component feeder include, for example, the outer diameter from the viewpoint of required load, required life, the required dimensions such as length, the coil spring wire diameter, winding outer shape, and the like.
The number of turns, pitch between lines, and the like are determined.

[0003]

However, when a conventional shape of an elliptical coil spring is conveyed by a component feeder, the coil springs become entangled with each other, making it difficult to separate the individual coil springs. There is a problem in that there is a problem in conveying or supplying the coil spring.

For example, when the interval a at the end of the winding pitch P of the elliptical coil spring 1 shown in FIG. 6 is increased, the coil springs 1 and 2 are easily entangled as shown in FIG. Such entanglement between adjacent coil springs 1 and 2 does not return to the original state when subjected to vibration, and the degree of entanglement further increases, making it difficult to separate the coil springs 1 and 2 from each other. Cannot be individually conveyed, which hinders the operation of assembling the individual coil springs 1 in the automatic assembling machine.

The present invention has been made in order to solve such a problem. By providing an elliptical coil spring in which the coil springs are less likely to be entangled with each other, the automatic assembling operation rate can be greatly increased. The purpose is to improve.

[0006]

According to a first aspect of the present invention, there is provided a coil spring according to the present invention, wherein at least one end of the coil spring has a pitch P ₁ : end pitch, and a pitch P _2. : Pitch at winding start (end of winding), P ₃ : Pitch adjacent to P, d: Wire diameter, D
_C : The long diameter of the elliptical spring is

(Equation 2) Characterized by having a shape satisfying the following.

[0007]

According to the coil spring of the present invention, the reason why the coil spring does not become entangled when Expression 2 is satisfied is explained as follows. First, FIG. 2 shows a state in which the coil springs are entangled. As shown in FIG. 2 geometrically showing the entangled state of the coil springs, a predetermined distance x,
_{y, L, L a, L} b, when the angle alpha, the condition that the coil spring is not entangled, the

(Equation 3)

(Equation 4) However,

(Equation 5) Becomes

By the way, the distances x and y are

(Equation 6)

(Equation 7) And L _a and L _b are represented by

(Equation 8)

(Equation 9) It is expressed as Therefore

(Equation 10) Substituting the expression into the expression, and then substituting this expression and the expression into the expression,

[Equation 11] Becomes Therefore, from each equation

(Equation 12) When satisfied, the coil spring will not get tangled.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. The coil spring according to the embodiment of the present invention is supplied by, for example, an automatic conveyance type component supply device 3 as shown in FIG. A spiral conveying path 5 is formed on the inner peripheral surface of the container 4 of the component supply device 3, and the individual coil springs 10 are conveyed on the conveying path 5 and taken out from the take-out port 6 in the direction a. When replenishing the coil spring 10 in the container 4, the coil spring 10 is replenished from the input port 4a at the upper end opening of the container 4.

The coil spring 10 is shown in FIG.
As shown in (B), the coil wire 11 is wound in an oval shape. Wire diameter of the coil wire 11 is uniform, P _1: end pitch, P _2: winding start pitch (winding end pitch), P _3: adjacent pitch adjacent to the P _2, d: wire diameter, D _C : The major axis of the elliptical coil spring.

(Equation 13)

When the shape of the elliptical coil spring satisfies the above equation (13), the second coil spring 20 adjacent to the first coil spring 10 moves relative to the first coil spring 10 in the direction of arrow c as shown in FIG. Fig. 4
As shown in (B), when the second coil spring 20 is further moved in the d direction with respect to the first coil spring 10, the springs come into contact with each other and move in a direction in which they are tangled. However, due to the above-described specific shape relationship between the two coil springs 10 and 20, the second
The portion 20a of the coil spring 20 does not move in the direction d with respect to the portion 10a of the first coil spring 10 from the position shown in FIG. That is, the coil springs 10 and 20 are prevented from moving in a direction that increases the degree of entanglement. Therefore, firm entanglement of the first coil spring 10 and the second coil spring 20 is prevented, and the first coil spring 10 and the second coil spring 20 are vibrated in the container 4 of the component supply device 3 shown in FIG. Is released again. Therefore, the individual coil springs 10 on the transport path 5
Are transported individually in a separated state.

Next, comparing the coil spring according to the embodiment with the coil spring according to the conventional comparative example,
It is as follows. According to the coil spring according to the conventional comparative example, when the second coil spring 2 moves in the direction of arrow e with respect to the first coil spring 1 as shown in FIG. Are entangled and further moved in the direction of the arrow e, as shown in FIG.
1c section of the coil spring 1
And the second coil spring 2 are entangled with each other. When the coil spring 1 becomes entangled, the coil springs 1 and 2 in the component supply device become entangled with each other due to the resilience of each other, so that the coil springs cannot be supplied. This is based on the fact that the shape of the conventional elliptical coil spring has a shape that is easily entangled.

As a result of an experiment conducted by the present inventor, the effect of winding the coil spring according to the above embodiment was compared with that of a conventional coil spring. The experimental result was as follows. The test was performed using a component feeder of a vibration transfer system.
As a result of the test, 126 out of 2000 coil springs were entangled with the conventional coil springs. On the other hand, according to the coil spring according to the embodiment of the present invention, 24 out of 2000 pieces were entangled. From this test result, according to the coil spring according to the embodiment of the present invention, it was possible to avoid the coil entanglement by 80% or more as compared with the conventional coil spring.

[0014]

As described above, according to the coil spring of the present invention, by setting the shape as described above, the springs are separated by vibration before the coil springs interfere with each other. Since the entangled state of each other can be greatly reduced, when such a coil spring is supplied by a vibration-conveying type component supply device, each coil spring is cut off and supplied to an automatic assembling device. There is an effect that the operation rate of the assembling device can be greatly increased.

[Brief description of the drawings]

FIG. 1A is a plan view showing a coil spring according to an embodiment of the present invention. (B) is a side view according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing an operation at the time of contact of a coil spring according to an embodiment of the present invention.

FIG. 3 is a perspective view showing an embodiment of the component supply device.

FIG. 4 is an explanatory view illustrating a state where coil springs according to an embodiment of the present invention are in contact with each other.

FIG. 5 is an explanatory view showing a state in which coil springs according to a conventional comparative example are in contact with each other.

FIG. 6A is a plan view showing a conventional coil spring. (B) is a side view showing a conventional coil spring.

FIG. 7 is an explanatory diagram illustrating a state in which coil springs of a conventional example are entangled with each other.

[Explanation of symbols]

 10 Coil spring 11 Coil wire 20 Coil spring

Claims (1)

(57) [Claims] In an elliptical coil spring, at least one end of the coil spring has a pitch P ₁ : an end pitch, a pitch P ₂ : a winding start (end) pitch, a pitch P ₃ : an adjacent pitch of P, d. : wire diameter, D _C: When oval spring major axis, Equation 1] A coil spring characterized by having a shape satisfying the following.