JP3789299B2 - Wave coil spring - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wave coil spring having a bending point in a load-deflection diagram.
[0002]
[Prior art]
Wave coil springs are widely used, for example, as clutch springs for automatic transmissions of automobiles or as springs for buffering in various devices. However, in this wave coil spring, a compression force is applied from both end winding parts. When is added, the operation is obtained by bending in the direction in which the peak and the valley are in close contact with each other.
[0003]
By the way, the wave coil spring used for the above-mentioned applications has a small spring constant due to variations in manufacturing of the wave height at the initial stage when the compression force is applied, and the wave coil spring is caused by the progress of the compression. When the spring is in close contact, the spring characteristic increases in spring constant, and in the middle region, the spring characteristic is generally linear.
However, depending on the situation of use, there are many cases where the spring characteristics are not linear in the intermediate region, but those having a bending point are required.
[0004]
Therefore, for example, as shown in Utility Model Registration No. 2586112, the height and circumferential length of some peaks are set larger than the height and circumferential length of the remaining peaks. When a compressive force is applied, only the peak portion having a large height and circumferential length is bent at the initial stage, and when the compression progresses, the large peak portion and the remaining peak portion are both bent. An improved wave coil spring having a spring characteristic having a bending point in a load-deflection diagram has been proposed.
[0005]
[Problems to be solved by the invention]
Usually, a wave coil spring is manufactured by coiling a coil-shaped spring material while alternately applying ridges and valleys that are curved in a wave shape to a strip-shaped spring material. Under the configuration in which the height and circumferential length of some peaks are changed, such as the wave coil springs, when changing the height of the peaks, the circumferential length of the peaks was changed. Since the portion does not coincide with the circumferential position of the remaining peak portion, the contact point is not determined, and it is difficult to predict the spring characteristics.
[0006]
[Means for Solving the Problems]
The present invention was developed in order to effectively solve the problems of the conventional improved wave coil spring. The invention according to claim 1 is a method in which a belt-shaped spring material is wound in a coil shape. The lower crest and the upper trough that face each other in the axial direction are point-contacted only on one of the outer peripheral edge side or the inner peripheral edge side in the free state of the spring, and the other has an interval. The belt-shaped spring material is inclined and curved in a wave shape toward the other side in the lower peak portion and toward the upper side in the upper valley portion toward the other.
[0007]
The invention described in claim 2 is based on the premise of claim 1 and adopts a configuration in which all contact points are on the outer peripheral edge side.
[0008]
The invention described in claim 3 is based on the premise of claim 1 and adopts a configuration in which all contact points are on the inner peripheral edge side.
[0009]
Therefore, in the invention according to claim 1, in the free state, the peak and the valley that are opposed in the axial direction are point-contacted only on one of the outer peripheral edge side or the inner peripheral edge side. Therefore, in the compression process, a spring characteristic having a predetermined bending point and load is obtained in the load-deflection diagram.
[0010]
In the invention described in claim 2, particularly in the initial stage, it is possible to increase the degree of bending by reducing the spring constant, and when the degree of bending is large, the natural frequency depends on the spring height. Since it will change greatly, the performance which suppresses the resonance of a spring is high, and the wave coil spring which is hard to resonate can be provided.
[0011]
In the invention described in claim 3, in particular, in the inspection process after manufacture, it is necessary to measure or visually observe the state of the line pitch, but all the contact points are on the inner peripheral edge side. The eye line reaches from the outer peripheral edge side to the inner peripheral edge side, and the inspection becomes easy.
[0012]
In addition, if it comprises so that a contact point may alternate on the outer periphery side and the inner periphery side under invention of Claim 1, in the process in which the end winding part of the spring which exhibits a cylindrical shape as a whole is compressed. It is possible to avoid the phenomenon of tilting toward the outer peripheral edge or, conversely, tilting toward the inner peripheral edge, and to operate while maintaining a parallel state.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, if the present invention is described in detail based on a preferred embodiment shown in the drawings, a wave coil spring according to the embodiment is also obtained by winding a belt-shaped spring material 1 in a coil shape as shown in FIG. A plurality of crests 2 and troughs 3 that are curved in a wave shape with respect to the axial direction are provided alternately for each winding part, and crests 2 and troughs 3 that face each other in the axial direction. It is to be contacted. In addition, the opposing peak part 2 and the trough part 3 are formed so that a position can be shifted and contacted for every winding part.
[0014]
And in this Embodiment, when making the peak part 2 and the trough part 3 which oppose the said axial center direction contact on the premise of such a structure, as shown to A of FIG. Only the outer peripheral edges 2a and 3a are brought into contact with each other, or as shown in FIG. In any case without making the line contact between the part 2 and the valley part 3, all the peak parts 2 and the valley parts 3 are brought into point contact in the free state. In the following description, for convenience, it is assumed that only the outer peripheral edges 2a and 3a of the portions 2 and 3 are in point contact.
[0015]
Therefore, in the case of the wave coil spring having such a configuration, when a compressive force is applied to the both ends of the coil winding portion, it is compressed in the axial direction. However, as shown in FIG. Since the end winding part is not a flat surface or there is a non-contact part due to manufacturing variations, the A section has a small spring constant. Next, in the B section, the outer peripheral edge 2a side of the peak portion 2 and the outer peripheral edge 3a side of the valley portion 3 are bent while maintaining a point contact state, so that a smaller spring constant than the line contact state is possible. It becomes.
[0016]
The deflection amount in the B section is predicted by the distances L1 and L2 of the inner peripheral edges 2b and 3b of A in FIG. 2. If L1 = L2, the deflection amount in the B section is approximately L1 × effective number of turns. Prediction of spring characteristics is easy. Further, the load increment in this section can also be predicted by treating it as a torsional deformation of a 1/2 wavelength bent beam.
[0017]
When the compression further proceeds, in the C section, in addition to the contact between the outer peripheral edges 2a and 3a of the parts 2 and 3, the inner peripheral edge 2b side of the peak part 2 and the inner peripheral edge 3b side of the valley part 3 Are also in contact with each other, and the peak portion 2 and the valley portion 3 are bent while being in line contact with each other, and become a spring constant in a linear region of a normal wave coil spring. In the subsequent D section, the crest 2 and the trough 3 are fully bent, and the entire wave coil spring starts to contact, so that a non-linear spring characteristic having a bending point T in each section can be obtained. It becomes.
[0018]
In this case, in particular, the fact that all the contact points are on the outer peripheral edges 2a and 3a side makes it possible to increase the bending degree by reducing the spring constant in the initial stage, and the bending degree can be increased. If it is large, the natural frequency greatly changes depending on the height of the spring. Therefore, it is possible to provide a wave coil spring that has a high performance of suppressing the resonance of the spring and hardly resonates.
[0019]
On the other hand, it is needless to say that the non-linear spring characteristic similar to the above can be obtained for the case where all the contact points are on the inner peripheral edges 2b and 3b side. Even if it is necessary to measure or visually check the situation, since the contact point is on the inner peripheral edge 2b / 3b side, the line of sight reaches from the outer peripheral edge side to the inner peripheral edge side, and the inspection is easy. There is. If this is on the outer peripheral edge 2a, 3a side, the line of sight does not reach the inner peripheral edge 2b, 3b side, and it becomes difficult to insert even a measuring instrument such as a caliper.
[0020]
Also, unlike the above, as shown in FIG. 4, if the contact point is configured to alternate between the outer peripheral edge 2a / 3a side and the inner peripheral edge 2b / 3b side, the end winding part of the spring having a cylindrical shape as a whole However, in the process of being compressed, it is possible to avoid the phenomenon of tilting toward the outer peripheral side or conversely tilting toward the inner peripheral side, and to operate while maintaining a parallel state. In this case, it is not necessary to make one change between the inside and outside of the outside, but it is possible to use an alternating place such as inside and outside the outside.
[0021]
【The invention's effect】
As described above, according to the present invention, by adopting the above-described configuration, in a free state, a peak and a valley that are opposed in the axial direction are point-contacted only on one of the outer peripheral edge side or the inner peripheral edge side. Therefore, in the compression process, a spring characteristic having a predetermined bending point and load is obtained in the load-deflection diagram.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a wave coil spring according to an embodiment of the present invention.
FIGS. 2A and 2B are explanatory diagrams showing a state in which a peak and a valley are in point contact only on the outer peripheral side, and FIG. 2B is a state in which the peak and the valley are in point contact only on the inner peripheral side. It is explanatory drawing which shows.
FIG. 3 is a diagram showing the spring characteristics of the wave coil spring of the present invention.
FIG. 4 is an explanatory diagram showing another example in which contact points are alternated inside and outside.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Plate-shaped spring material 2 Peak part 2a Outer periphery 2b of peak part Inner peripheral edge 3 of peak part Valley part 3a Outer peripheral edge 3b of valley part Inner peripheral edge T of valley part Bending point

Claims (3)

  A belt-shaped spring material is wound in a coil shape, and a lower peak and an upper valley that are opposed to each other in the axial direction are arranged on one of the outer peripheral edge and the inner peripheral edge in the free state of the spring. Only the point contact is made, and on the other side, the belt-like spring material is inclined to the lower side as it goes to the other side in the lower peak, and to the upper side as it goes to the other side in the upper valley, A wave coil spring that is curved in a wave shape. 2. The wave coil spring according to claim 1, wherein all contact points are on the outer peripheral edge side. 2. The wave coil spring according to claim 1, wherein all contact points are on the inner peripheral edge side.

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