JPS6243769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a barrel-shaped coil spring (a barrel-shaped coil spring in a broad sense) and a manufacturing apparatus used to carry out the method.

Conventionally known barrel-shaped coil springs have characteristics such as: At maximum compression, adjacent wound wires are positioned inside and outside to form a flat spiral shape, the spring compression length is extremely small, and it is lightweight. It has excellent utility in spring application fields. however,
For example, barrel-shaped coil springs based on the hot-forming method using large diameter wires, which are used in automobile suspension systems, are extremely difficult to mass-produce due to their unique shape constraints, and their usefulness has not been widely acknowledged. However, the reality is that its popularity is extremely low.

In view of the above circumstances, the present invention provides a method for manufacturing barrel-shaped coil springs that can be mass-produced, as well as a manufacturing device used in the method, and aims to popularize barrel-shaped coil springs, thereby improving the cushioning performance in application fields such as vehicles. The purpose is to contribute to the improvement of

The present invention will be explained below based on the drawings. Figure 1 shows the original shape of a barrel-shaped coil spring, with end-wound portions having a minimum winding diameter D ₁ at the left and right ends in the illustration, and a maximum winding diameter D ₂ at the center of the diagram, made of wire rods 1 of the same diameter. It is wound so that the winding diameter gradually increases in each of the _two directions of the maximum winding diameter D from the end winding.
Configure R. The manufacturing method of the above-mentioned barrel-shaped coil spring according to the present invention involves winding the end winding strip diameter D ₁ of each left half portion L by approximately 3/4 turns into a flat shape using the wire rod 1 having a predetermined diameter. Winding is performed so that the winding diameter gradually increases in accordance with the pitch angle, and the winding is completed near the final end of each left half portion L as a first stage. That is, the winding of each left half part L is completed as the first step at the position of the contact point P of _the left and right half parts L and R in FIG. 1 is tangential to point _P1 and linearly in the direction of the corresponding pit angle. Then, from the _P1 point to the 90° point of the P point in each right half R in FIG.
A wire rod having a considerable length reaching _two points P after winding is stretched into the above-mentioned straight line to obtain the straight line portion 5 shown in FIG.
Therefore, the straight line portion 5 is established as the developed length of the winding with the starting point as point _P1 , the end point as point _P2 , and the middle point as point P.

Next, as a second step, the winding diameter is gradually reduced in a spiral manner according to a predetermined pitch angle, with the straight line portion 5 becoming tangential from the _P2 point of the maximum winding diameter portion of each right half R. The preforming of the barrel-shaped coil spring shown in the third figure is completed by winding in the direction of the end turn and winding a predetermined end turn symmetrically with each left half. In the preforming, as shown in the third diagram, a small amount of the wire rod equivalent to the winding is reserved as a straight wire rod in the tangential direction of the winding circle around the contact point P of the left and right half portions L and R, and Therefore, the left and right halves are continuous with each other, and the winding axes 3 and 4 of the left and right halves are substantially parallel.

Finally, in the third step, the maximum winding diameter is
It is characterized in that the finished shape of the barrel-shaped coil spring shown in FIG. 1 is obtained by performing curving and forming processing to a radius of curvature corresponding to D ₂ .

In the above-described manufacturing method according to the present invention, the straight portion 5 has exactly the length equivalent to the unwound wire material at the end of each half portion centering on the point P, and both ends thereof are in the tangential direction of the winding diameter. Since the lead angle is maintained at , a predetermined barrel-shaped coil spring can be easily and accurately formed by the third step of bending.

Next, the invention of a barrel-shaped coil spring manufacturing apparatus used to carry out the above-described manufacturing method will be described. Fourth
One embodiment is shown in the figure, and the mold 6L is a winding mold for each of the left half parts, and has a truncated conical shape corresponding to the shape and size of each left half part L, and has a predetermined surface. A wire guide groove 7 corresponding to the wire diameter and lead angle is bored, and the wire rod is removably supported on a rotating shaft 8L having the same axis. Further, the rotating shaft 8L is connected to a rotating mechanism, rotates together with the mold 6L, can freely select the number of rotations and rotation direction, and is constituted by a mechanism that can freely move linearly in the left and right directions in the drawing. On the other hand, mold 6R rotation shaft 8
R is a winding mold for each of the right half portions and its rotation axis, which is constructed in the same manner as the mold 6L, and is independently equipped with the same rotation and linear movement mechanisms as described above. The molds 8L and 8R are parallel, and the distance between their axes 9 and 10 is the same as that of the molds 8L and 8R.
When moving in the left-right direction, the coil spring is adjusted and maintained as small as possible without interference between the maximum winding diameter portion of the barrel-shaped coil spring to be formed and the forming die.

Therefore, the molds 8L and 8R are each characterized by a structure that allows independent rotation, independent left-right linear movement, and a mechanism for adjusting the mutual axial distance.

Next, to describe its function, the mold for the barrel-shaped coil spring to be molded is engaged as shown in Figure 4.
The distance between the axes is adjusted and fixed based on the conditions. Next, in order to form each left half portion L, as shown in FIG.
is clamped at a predetermined position of the mold 6L in the same manner as in the prior art (not shown), and as the rotating shaft 8L rotates, the wire 1 winds and forms a coil along the guide groove ₇ . Stop rotation at a point.

Subsequently, as shown in FIG. 6, the mold 6R moves in the direction of the arrow shown in the figure and stops at a normal position, and at the same time, the mold 6L releases the clamp and moves in the direction of the arrow shown while rotating slightly in the opposite direction. , completely detached from each molded left half portion L. At P ₁ , the wire 1 is maintained tangent to the winding circle and straight in the direction of the lead angle θ.
Straight line section 5 with a predetermined exact length from ₁ point P
can be clamped (not shown) at _two points P while accurately matching the lead angles.

Next, in the same way as each left half part 6L, each right half part 6L
R is molded, and at the same time as the mold 6R is stopped, it is completely separated in the direction of the arrow shown in the figure to the form shown in the seventh figure in the same manner as described above, to accurately and easily obtain preforming of the barrel-shaped coil spring to be molded in the manufacturing method described above. Can be done.

As described above, the present invention pioneers the production technology of barrel-shaped coil springs made of large-diameter wire rods, which has been considered difficult in the past, and enables mass production of them easily and accurately.
This will promote mass production of barrel-shaped coil springs for automobile suspension, and will significantly contribute to improving vehicle shock absorbing function, reducing vehicle weight, and saving resources.

The barrel-shaped coil spring of the present invention is not limited to the above-mentioned embodiments, and includes barrel-shaped coil springs that have a curved generatrix shape when no load is applied, similarly straight barrel-shaped coil springs, and taper-shaped coil springs that gradually reduce the wire diameter from the center of the spring toward both ends of the spring. It can be broadly interpreted and applied to barrel-shaped coil springs made of wire.

The forming procedure is therefore not limited to the above example, but could also start from each right half, depending on the winding direction. On the other hand, the length of the straight portion 5 in the above-mentioned manufacturing method is not limited to the diameter of the maximum winding or 1/2 of the circumference of the maximum winding diameter. The minimum length that can avoid mutual interference between the two and the interference between the wire and the molding die is preferable, and is arbitrarily selected depending on the wire diameter and coil diameter of the spring to be molded. Also, the requirements for the above-mentioned tangential direction in the straight section 5, the lead angle and the parallelism of each of the two halves connected by the straight section 5 are proportional to the degree to which the requirements are completely fulfilled. This makes it possible to more accurately and easily form a shaped coil spring, but the invention can also be practiced when the above requirements are not met. Further, in the above embodiments, the mold has guide grooves formed on its surface, but the present invention also includes a simple truncated cone-shaped mold in which the wire is guided by other suitable guides. , the material of the mold, the mechanical properties, the clamping mechanism, etc. can be selected and applied as desired according to conventional techniques.

[Brief explanation of the drawing]

Figure 1: Top view of barrel-shaped coil spring, Figure 2:
A plan view showing the manufacturing method of the present invention, FIG. 3: A plan view A and its side view, FIG. 4, also showing the manufacturing method:
Plan view of an embodiment of the manufacturing apparatus of the present invention, Nos. 5 to 7
Figure: FIG. 4 is an explanatory diagram of the operation of the embodiment of FIG. 4. Explanation of main symbols, 1: Wire rod, 2: Spring height direction center line, 3, 4: Winding axis, 5: Straight line part, 6
L, 6R: Molding mold, 7: Guide groove, 8L, 8R: Rotating shaft, 9, 10: Molding mold axis, P: Contact point of each left and right half, L: Each left half, R: Each right half , is.

Claims (1)

[Claims] 1. Winding in the direction from the minimum winding diameter to the maximum winding diameter of one of the two halves divided by the center line in the height direction of the barrel-shaped coil spring. death,
Furthermore, the same wire is wound in the direction from the maximum winding diameter part to the minimum winding diameter of each other half, and the length is at least longer than the maximum winding diameter,
The formed two halves are formed by a straight line portion having a length equivalent to the unwound wire material and centered at the contact point of each of the two half portions.
Each of the two halves is preformed into an interconnected shape, and then the straight part is subjected to a predetermined curving and shaping process, and the winding axes of the two halves overlap. Manufacturing method for barrel-shaped coil springs. 2 Equipped with two frusto-conical molds for guiding and winding the wire, each having a shape corresponding to the winding shape of each of the two halves divided by the height center line of the barrel-shaped coil spring. The forming die has two parallel axes having a center-to-center distance equal to or greater than the maximum winding diameter of the barrel-shaped coil spring, and is positioned such that the truncated conical shapes are in opposite directions; A manufacturing device for a barrel-shaped coil spring, characterized by a structure that is coaxially supported on the bottom surface of the shape, and has a separate rotation mechanism and a separate axial linear movement mechanism.