JP4184757B2 - Compression coil spring - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a compression coil spring used for a member that performs an arc motion such as a strut suspension (automatic suspension device) using a shock absorber (buffer) for a strut (wheel positioning support) of an automobile.
[0002]
[Prior art]
As shown in FIG. 5, the strut suspension receives the arc motion P1 of the wheel 54 attached to the tip of the lever 53 by the linear motion P2 of the shock absorber 50 attached between the lever 53 and the vehicle body 55. For this reason, the road load line AA and the spring reaction force line RA of the compression coil spring 52 do not coincide with each other, and a sliding resistance is likely to occur between the cylinder 51a and the rod 51b of the strut 51. As a result, a frictional force is generated in the shock absorber 50, the smooth sliding action is hindered, and the steering performance (handling) is lowered.
[0003]
In order to realize a compression coil spring that can be used for a member that performs such an arc motion , it is necessary to cancel the bending moment generated in the strut. Therefore, a spring has been proposed in which the line of action of the compression coil spring is curved so that the amount of expansion / contraction (extension / contraction load) differs between the side with a large amount of movement and the side with a small amount of movement, thereby canceling the lateral force acting on the strut. Yes.
[0004]
As an example of a conventional compression coil spring, the coil shaft is formed to be curved, and the pitch of the upper and lower seat windings is set so that the lower and upper seat surfaces wound with pigtails are inclined by a predetermined angle. (For example, refer to Patent Document 1).
[0005]
Further, the center winding axis of the lower end coil and the upper end coil wound with the pigtail is formed so as to be offset by a predetermined distance with respect to the linear coil axis of the body portion, and the lower seat surface and the upper seat surface are predetermined. Some have disclosed a structure in which the pitch of the upper and lower cigarettes is set so as to be inclined at an angle (see, for example, Patent Document 2).
[0006]
[Patent Document 1]
JP 2002-234324 A (27th paragraph, FIG. 1)
[Patent Document 2]
Japanese Patent Laid-Open No. 2002-1778736 (27th to 28th paragraphs, FIG. 1)
[0007]
[Problems to be solved by the invention]
However, if only the pitch of a specific portion of one spring is changed, a stress concentration point is generated in the vicinity of the change point, and metal fatigue occurs there, so that there is a disadvantage that the life of the spring is shortened.
[0008]
In both Patent Document 1 and Patent Document 2 described above, since the pitch is partially changed in order to incline the lower seat surface of one roll and the upper seat surface of one roll, there are at least two stress concentration points. Was. In addition, if the tilt angle between the lower and upper cigars wound with the pigtail and the lower and upper bearing surfaces is slightly out of order, the characteristics of the entire spring will change significantly, requiring fine adjustment during production. There was a problem.
[0009]
The present invention has been made in view of such problems, and an object of the present invention is to provide a compression coil spring that can change the direction of repulsive load as well as spring deflection (deflection) and has a long life.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the compression coil spring according to the present invention is used for a member that performs an arc motion, and the spring action line follows the arc motion by providing a difference in the spring constant k on the left and right sides. A compression coil spring that is curved , and is composed of one coiled wire, and at least a large-diameter coil portion (12, 22, 32) and a small-diameter coil portion (14, 24, 36) are continuous. They are characterized in that they appear repeatedly in units of two or more coil portions.
[0011]
Thus, by using a coil portion of two or more turns as a unit, stress concentration is relaxed, and the life of the spring is dramatically increased as compared with the conventional one. In addition, the load direction is not changed locally, but the load direction is changed by repeatedly appearing in units of two or more coil portions, so that delicate adjustments can be easily made during production.
[0012]
In the compression coil spring, the small-diameter coil portion is preferably configured such that its coil center is shifted in the circumferential direction relative to the coil center of the large-diameter coil portion .
[0013]
If it does in this way, a load direction can be changed easily. When the coil center is relatively shifted in the circumferential direction, it may be shifted by two or more coil portions having the same coil diameter. However, if the coil diameters are different, the spring constant can be changed more greatly. A stronger lateral force can be added. Also, even if the pitch is the same, the pitch angle becomes larger and stronger when the coil diameter is small, so that it is possible to meet the demand for free repulsive force and to disperse the stress concentration points over a long line length. A compression coil spring is obtained.
[0014]
You may comprise so that the center axis line of either one of a large diameter coil part and a small diameter coil part may be made straight or curved, and the other may be made straight or curved. In this way, a long-life compression coil spring is obtained in which one side of one coil spring is strong and the other is weak.
[0015]
The above-described compression coil spring according to the present invention may include a plurality of coil portions each having a plurality of coil portions having different coil diameters and coil turn ratios . Even in this case, the load direction of the compression coil spring can be easily changed.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
(Basic configuration)
A compression coil spring that can be attached to a member that performs an arc motion, such as a suspension of an automobile, is weak on one side (small spring constant k) and strong on the other side (spring constant k is small). Large). In such a spring, the load direction does not coincide with the coil central axis direction and is curved.
[0017]
Referring to FIG. 5, since the center of the arc motion is at the center of the left and right tires, the compression coil spring 53 expands and contracts greatly toward the outer side of the lever 53 (that is, the tire side) when viewed from the vehicle body center. Therefore, the compression coil spring 52 is attached so that the side with the larger spring constant k is on the outside and the side with the smaller spring constant k is on the inside.
[0018]
If it does in this way, a spring action line will curve in the shape which follows the circular motion of a tire, and lateral force which counteracts lateral force which acts on a strut can be given.
[0019]
(Embodiment of the Invention)
In order to realize such a spring, the compression coil spring according to the present invention is not provided with a strong and weak portion by one turn as in the prior art, but has a structure in which stress can be naturally distributed at a long line length larger than one turn. More specifically, the strength portion is provided by repeatedly providing a coil portion having two or more turns as a unit. In this way, stress can be dispersed over a longer distance, stress concentration points are less likely to be formed and the life is extended, and various effects described later are obtained.
[0020]
The coil which becomes a repeating unit can bend the spring action line of the entire compression coil spring by shifting the coil center from each other, making the coil diameters different from each other, changing the coil pitch, or a combination thereof. it can.
[0021]
-Basic principle of changing spring constant k-
(1) The smaller the coil diameter, the larger the spring constant k.
(2) The larger the pitch, the larger the spring constant k.
-Basic principles for changing the load direction-
(3) When the centers of the two coils are different, the repulsive load direction deviates from the central axis.
(4) When the pitch is changed, the load direction deviates from the central axis.
[0022]
The present invention applies these basic principles to a unit of a coil portion having at least two turns. That is, in the conventional compression coil spring , in order to curve the load direction, the pitch of one coil spring is varied locally or in one turn cycle, or only the coil diameter of one turn is changed. However, in the present invention, the load direction is curved by applying a strength to one spring with a coil portion of at least two turns or more as a unit. Examples will be described below.
[0023]
【Example】
(Example 1)-Shifting the coil diameter and coil center-
Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram for explaining a compression coil spring according to the present invention, FIG. 1 (a) is a front view, and FIG. 1 (b) is a view of two windings of a coil viewed downward from line BB in FIG. 1 (a). It is a figure which shows a part, FIG.1 (c) is a figure for demonstrating the action line of a spring.
[0024]
In FIG. 1A, the compression coil spring 10 is composed of a single wire, and a plurality of them are provided in units of two turns in which a large-diameter coil portion 12 and a small-diameter coil portion 14 are combined. It becomes. In consideration of the transition portion from the large diameter coil portion 12 to the small diameter coil portion 14, one large diameter coil portion 12 and the small diameter coil portion 14 do not need to be formed exactly one by one, It is sufficient that the total number of windings is 2 (or more than 2).
[0025]
The plurality of small-diameter coil portions 14 (14a to 14e) are configured such that the coil axis 11 is positioned on a curved line, while the coil axis 13 of the large-diameter coil portion 12 is positioned on the same straight line. It is configured. In addition, although this coil is made into the equal pitch coil, it does not necessarily need to be an equal pitch. The coil having such a shape can be manufactured relatively easily by inputting appropriate data to the coiling machine.
[0026]
As shown in FIG. 1B, each of the small-diameter coil portions 14 (14a, 14b, 14c, 14d, 14e) is rotated by 90 ° in the circumferential direction with respect to the large-diameter coil. Is arranged.
[0027]
As a result, as shown in FIG. 1 (a), the uppermost small-diameter coil portion 14a is shifted to the left side in the drawing, and the coil center is shifted to the left side from the center of the large-diameter coil portion. The second small-diameter coil portion 14b from the top is located substantially at the center, and its coil center is substantially the same position (near the axis) as the coil center of the large-diameter coil portion. The third small-diameter coil portion 14c from the top is on the right side in the drawing. The fourth small-diameter coil portion 14d from the top is located at the center, and the center of the coil is substantially at the same position (on the axis) as the center of the large-diameter coil portion. The fifth small-diameter coil portion 14e from the top is shifted to the left side in the drawing, and the center of the coil is shifted to the left side from the center of the large-diameter coil portion. It comes to substantially the same position as the small-diameter coil portion 14a described.
[0028]
Therefore, when the center points of the small-diameter coil portions 14 are connected, the coil center axis is a convex bow on the right side, as shown by the alternate long and short dash line 11 in FIG.
[0029]
Since this compression coil spring 10 includes portions with different coil diameters, the small-diameter coil portion has a larger spring constant k than the large-diameter coil portion based on the principle (1) described above. Further, when the compression coil spring 10 is viewed as a whole, the axis of the small-diameter coil portion is shifted to the left relative to the large-diameter coil portion. Therefore, from the above principle (3), FIG. In the drawing, the spring constant k is larger on the left side than on the right side.
[0030]
As a result, when a compressive load is applied to the coil spring of this structure from below, the action line 15 of the spring 10 is curved in a convex arc shape to the left as shown in FIG.
[0031]
Therefore, when this spring is used for the left suspension (that is, the tire is installed so as to be on the left side of the spring 10), the spring acting line is curved in such a manner as to follow the arc motion of the tire, and the lateral acting on the strut is applied. A lateral force that cancels the force can be applied.
[0032]
Although the coil pitch L is illustrated as being constant regardless of the coil diameter, the above-described principle (2) is applied, and the left side in the example of FIG. If the pitch of is increased, the applied lateral force is further increased. However, in that case, if the coil pitch is locally increased, the load is concentrated there, so that it is preferable that they appear repeatedly in units of at least two or more coil portions. It is because the essence of the present invention is to eliminate the stress concentration point in this way.
[0033]
Further, as shown in FIGS. 2A and 2B, the axis 21 of the small-diameter coil portion 24 may not be curved, but may be linear like the axis 23 of the large-diameter coil portion. That is, instead of rotating the small-diameter coil portion 24 by 90 °, the small-diameter coil portion 24 may be arranged at the same position every one cycle (that is, 360 °). Even in this case, as shown in FIG. 2C, the action line 25 of the spring has an arc shape, and when a compression load is applied to the spring, a lateral force in the A direction (a force to bend in the A direction) is applied. Is done.
[0034]
In this case, as compared with the case shown in FIG. 1 described above, the difference in the spring constant k is reduced, and the applied lateral force is slightly reduced. That is, the left and right balance of the spring constant can be adjusted in this way. Thus, when strength is provided in the repeating unit, the stress concentration point is eliminated and the life is longer than that of the conventional spring. Note that these can be easily changed in design by appropriately applying the above-described principle.
[0035]
(Modification of the first embodiment)
The large-diameter coil portions 12 and the small-diameter coil portions 14 are not alternately arranged one by one in one wire, but a plurality (or one) of large-diameter coil portions 12 and a plurality ( Alternatively, the small-diameter coil portions 14 may be alternately arranged. In a broad sense, these are included in “providing a strong and weak portion in units of at least two or more coil portions (= large diameter coil portion and small diameter coil portion)”.
[0036]
Also, the axis of the large-diameter coil portion 12 is bent and the axis of the small-diameter coil portion 14 is arranged on the same straight line, or the axes of both the large and small coil portions are bent. May be. Even in this case, a difference can be provided between the left and right spring constants k. These can be easily changed in design by appropriately applying the above-mentioned principle.
[0037]
(Example 2)-Changing the coil diameter and the number of coil turns-
FIGS. 3A and 3B are diagrams for explaining the compression coil spring of the present invention. FIG. 3A is a front view, and FIG. 3B is a view of two coils viewed downward from the line BB ′ in FIG. It is a figure which shows a winding part, FIG.3 (c) is a figure for demonstrating the action line of a spring.
[0038]
In FIG. 3, the coil spring 30 is formed by combining a coil portion 32 having a large diameter and a coil portion 36 having a small diameter. In this example, large-diameter coil portions 32 and small-diameter coil portions 36 appear alternately and repeatedly. Also, the large-diameter coil portion 32 of the coil spring 30 has a different winding ratio such that the number of turns is, for example, 0.8, and the number of turns of the small-diameter coil portion 16 is, for example, 1.2.
[0039]
As shown in FIG. 3B, center axes 31 and 33 of a plurality of large-diameter coil portions 32 and small-diameter coil portions 36 are on the same straight line.
[0040]
However, since a small-diameter coil portion having a relatively large turn ratio repeatedly appears on the left side of the central axis 31 (33) of the coil spring 30 repeatedly, the principle (1) as a whole on the drawing of FIG. The left spring constant k increases and the right spring constant k decreases.
[0041]
As a result, when a load is applied to the coil spring having this structure from below, as shown in FIG. 3C, the action line 35 of the spring 30 indicated by the alternate long and short dash line is curved in a circular arc convex to the left as a whole. To do.
[0042]
Therefore, when this spring is used for the left suspension (that is, the tire is placed so as to be on the left side of the spring 30), the spring acting line is curved in such a manner as to follow the arc motion of the tire, and the lateral acting on the strut is applied. A lateral force that cancels the force can be applied.
[0043]
In addition, although the winding ratio of the large and small coil portions is 0.8 and 1.2 (2 windings in total), the present invention is not limited to this. These may repeatedly appear in a coil spring made of a single wire.
[0044]
Although the coil pitch L is illustrated as being constant regardless of the size of the coil diameter, the above-described principle (2) is applied, and the pitch on the side where the spring constant k is desired to be increased (the left side in the example of FIG. 3). If the is increased, the lateral force applied is further increased. Further, the axis of the small-diameter coil portion 14 may not be curved, and the axis of the small-diameter coil portion 14 may coincide with the straight line. In this way, the difference in spring constant k is reduced and the applied lateral force is reduced. These can be easily changed in design by appropriately applying the above-mentioned principle.
[0045]
(Other examples)
The present invention is not limited to the above-described embodiment, and an embodiment in which these are appropriately combined according to the above-described principle (1) to principle (4) in units of two or more turns is also possible. For example, as shown in FIG. 4A, when the coil diameter is gradually reduced toward the center side and is gradually changed, the stress is dispersed and the life of the spring is extended.
[0046]
Similarly, as shown in FIG. 4B, the coil diameter may be gradually increased toward the center side and may be sequentially changed. That is, as shown in FIGS. 4A and 4B, a plurality of coil portions having different coil diameters and coil turns may be provided as a unit.
[0047]
Alternatively, the pitch angle may be changed, and the strength of one coil spring may be increased in units of two or more turns. However, when changing the pitch angle, it is important not to change the pitch angle locally, but to have a plurality of coils in units of at least two or more turns.
[0048]
【The invention's effect】
Since the compression coil spring according to the present invention is configured so that the stress concentration point is dispersed as a whole in units of two or more turns, it has a longer life than the conventional one and is easy to fine-tune.
[Brief description of the drawings]
FIG. 1 is a view for explaining a compression coil spring of the present invention described in the first embodiment, FIG. 1 (a) is a front view, and FIG. 1 (b) is a view in FIG. ) Of the coil viewed downward from the line BB ′, and FIG. 1C is a diagram for explaining the action line (repulsion axis) of the spring.
2 is a view for explaining a compression coil spring of the present invention in the first embodiment, FIG. 2 (a) is a front view, and FIG. 2 (b) is a view of FIG. 2 (a). FIG. 2C is a diagram showing two winding portions of the coil as viewed downward from the line BB ′, and FIG. 2C is a diagram for explaining the action (repulsion axis) of the spring.
3 is a view for explaining a compression coil spring according to the present invention in a second embodiment, FIG. 3 (a) is a front view, and FIG. 3 (b) is a view of FIG. 3 (a). It is a figure which shows the two winding parts of the coil seen below from line BB ', and FIG.3 (c) is a figure for demonstrating the action line of a spring.
4 (a) and 4 (b) are diagrams for explaining a compression coil spring of the present invention in another embodiment.
FIG. 5 is a view showing a strut suspension.
[Explanation of symbols]
10 compression coil spring 11 axis of small diameter coil portion 13 axis of large diameter coil portion 14 small diameter coil portion 15 action line 50 shock absorber 51a cylinder 51b rod 52 compression coil spring 53 lower arm 54 wheel 55 vehicle body AA road load line RA spring Reaction line

Claims (4)

  A compression coil spring that is used for a member that performs an arc motion and is curved in such a manner that a spring action line is curved along the arc motion by providing a difference in the spring constant k on the left and right sides. It is composed of a wire rod, and at least two coil portions of at least a large-diameter coil portion (12, 22, 32) and a small-diameter coil portion (14, 24, 36) are continuous and appear repeatedly as a unit. A compression coil spring.   2. The compression coil spring according to claim 1, wherein the coil portion of the small diameter is shifted in the circumferential direction relative to the coil center of the coil portion of the large diameter.   The central axis of one of the large-diameter coil (12, 22, 32) and the small-diameter coil portion (14, 24, 36) is linear or curved, and the other is curved or linear. The compression coil spring according to claim 1 or 2, characterized in that. The compression according to any one of claims 1 to 3, wherein a plurality of the coil portions having two or more turns are present in units of a plurality of coil portions having different coil diameters and coil turns ratios. Coil spring.

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