Spiral spring device

Abstract

A main spring (11) and an insulator (12) are provided with a support groove (13) extending around a coil axis (O) and fitted to a lower end portion of the main spring, the lower end portion of the main spring is bonded to an inner surface (13a) of the support groove, a plurality of interval protrusions (14) supporting an outer peripheral surface of a wire (W) are provided on the inner surface of the support groove, the support groove extends in an angle range of 180° or more and 360° or less around the coil axis, and a proportion of a volume of the interval protrusions in a gap between the inner surface of the support groove and the outer peripheral surface of the wire is larger in a central portion in a circumferential direction extending around the coil axis in the gap than in other portions.

Description

Technical Field

[0001] This invention relates to a helical spring device.

[0002] This application claims priority based on Japanese Patent Application No. 2020-064642, filed in Japan on March 31, 2020, the contents of which are incorporated herein by reference. Background Technology

[0003] As a helical spring device used in a suspension device, the following structure is currently known: a main spring having a wire extending helically around a coil axis in the vertical direction, and an insulator supporting the lower end of the main spring from below the main spring, a support groove extending around the coil axis and fitting into the lower end of the main spring provided in the insulator, the lower end of the main spring being bonded to the inner surface of the support groove, and a plurality of spaced protrusions supporting the outer peripheral surface of the wire provided on the inner surface of the support groove.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-15249 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, in the existing helical spring device, there is room for improvement in terms of ensuring the bonding strength between the lower end of the main spring and the inner surface of the support groove while suppressing costs.

[0009] The present invention was made with this in mind, and its object is to provide a helical spring device that can reduce costs while ensuring the bonding strength between the lower end of the main spring and the inner surface of the support groove.

[0010] Solution for solving the problem

[0011] To address the aforementioned issues and achieve this objective, the first embodiment of the present invention provides a helical spring device comprising: a main spring having a wire extending helically in a vertical direction around a coil axis; and an insulator supporting the lower end of the main spring from below, wherein the insulator has a support groove extending around the coil axis and fitting into the lower end of the main spring, the lower end of the main spring being bonded to the inner surface of the support groove, and a plurality of spaced protrusions supporting the outer peripheral surface of the wire being provided on the inner surface of the support groove, the support groove extending within an angular range of 180° to 360° about the coil axis, and the proportion of the volume of the spaced protrusions in the gap between the inner surface of the support groove and the outer peripheral surface of the wire being greater in the central portion of the gap extending around the coil axis than in other portions.

[0012] According to the present invention, the proportion of the volume of the spacer protrusion in the gap between the inner surface of the support groove and the outer peripheral surface of the wire is larger in the circumferential central portion of the gap than in other portions. Therefore, when a vertical compressive force is applied to the main spring, the volume of the circumferential central portion, where the applied load is relatively low, becomes smaller in the adhesive layer between the lower end of the main spring and the inner surface of the support groove, while the volume of the end portion, where the applied load is relatively high, becomes larger, thus ensuring the strength of the circumferential end portion. This allows for ensuring the adhesive strength between the lower end of the main spring and the inner surface of the support groove while reducing the amount of adhesive used, thereby reducing costs.

[0013] In a second embodiment of the present invention, in the helical spring device of the first embodiment of the present invention, a plurality of the spacer protrusions are formed in the same shape with the same size as each other.

[0014] In this case, since multiple spacer protrusions are formed in the same shape with the same size, multiple spacer protrusions can be easily formed, and multiple spacer protrusions can easily and uniformly support the outer periphery of the wire with less deviation.

[0015] Invention Effects

[0016] According to the present invention, it is possible to suppress costs while ensuring the bonding strength between the lower end of the main spring and the inner surface of the support groove. Attached Figure Description

[0017] Figure 1 This is a perspective view of a helical spring device shown as one embodiment of the present invention.

[0018] Figure 2 It means Figure 1 A top view of a portion of a helical spring device.

[0019] Figure 3 yes Figure 2 The helical spring device shown is viewed in a sectional view along line III-III. Detailed Implementation

[0020] The following is for reference Figures 1-3 One embodiment of the helical spring device of the present invention will be described.

[0021] The helical spring device 1 includes: a main spring 11, whose wire W extends helically in the vertical direction around a coil axis O; and an insulator 12 that supports the lower end of the main spring 11 from below. That is, the vertical direction refers to the direction of the coil axis O. The helical spring device 1 is used, for example, in a suspension device having a shock absorber inserted into the inside of the main spring 11 and a support frame mounted on the upper end of the shock absorber.

[0022] The main spring 11 is an open-type helical spring in which the end portion w1 of the wire W moves upward and downward from the inner side of the wire W adjacent to the end portion w1 in the direction of the coil axis O. The cross-sectional shape of the wire W is the same along its entire length including the end portion w1. In the illustrated example, the cross-sectional shape of the wire W is circular.

[0023] Furthermore, the main spring 11 can also be a closed helical spring, in which the end portion w1 of the wire W and the adjacent inner side of the wire W in the direction of the coil axis O abut and overlap. In this structure, the end portion w1 of the wire W can also be processed, for example, by grinding, to form a flat surface extending in a horizontal direction orthogonal to the vertical direction and facing outward in the vertical direction. The cross-sectional shape of the wire W can also be, for example, rectangular.

[0024] Insulator 12 is formed, for example, of an elastic material such as rubber. Figure 2 As shown, viewed from above, the insulator 12 has an arc shape extending around the coil axis O. The insulator 12 extends within an angle range of 180° to 360° with the coil axis O as the center.

[0025] A support groove 13 is provided in the insulator 12, extending around the coil shaft O and engaging with the lower end of the main spring 11. The support groove 13 extends within an angle range of 180° to 360° with the coil shaft O as the center. Figure 3 As shown, an adhesive layer 16 is provided between the inner surface 13a of the support groove 13 and the lower end of the main spring 11, and the lower end of the main spring 11 is bonded to the inner surface 13a of the support groove 13.

[0026] The inner surface 13a of the support groove 13 is formed as a concave curved surface that bends along the outer periphery of the wire W. The support groove 13 is integrally opened to one side, above, and radially (in a direction orthogonal to the direction of the coil axis O) extending around the coil axis O.

[0027] Furthermore, the support groove 13 can also be a structure with openings on both sides in the circumferential direction, or a structure with the outer side closed in the radial direction.

[0028] Multiple spaced protrusions 14 are provided on the inner surface 13a of the support groove 13 to support the outer peripheral surface of the wire W.

[0029] The volume of the spacer protrusion 14 accounts for more than 10% of the gap between the inner surface 13a of the support groove 13 and the outer peripheral surface of the wire W, and the volume of the adhesive layer 16 accounts for less than 90% of the same gap. When the spacer protrusion 14 is cylindrical, the volume of the spacer protrusion 14 also includes the volume of the internal space of the spacer protrusion 14.

[0030] The proportion of the volume of the spacer protrusion 14 in the gap between the inner surface 13a of the support groove 13 and the outer peripheral surface of the wire W is greater in the central portion of the circumferential direction extending around the coil axis O in the gap than in other portions. That is, the proportion of the volume of the adhesive layer 16 in the gap is smaller in the central portion of the circumferential direction in the gap than in other portions.

[0031] The circumferential central portion of the gap refers to the portion that is circumferentially clamped by portions on both sides of the gap that are 5% to 45% of the total circumferential length of the gap, relative to the center of the gap (the portion located at an equal distance from one end and the other end of the gap).

[0032] In the illustrated example, the proportion of the volume of the spacer protrusion 14 in the gap gradually decreases as it moves away from the circumferential center, while the proportion of the volume of the adhesive layer 16 in the gap gradually increases as it moves away from the circumferential center. At the circumferential ends of the gap, the proportion of the volume occupied by the spacer protrusion 14 is set to 10% or less, and the proportion of the volume occupied by the adhesive layer 16 is set to 90% or more.

[0033] Furthermore, the proportion of the volume of the spacer protrusion 14 in the gap can be the same in the entire region of the gap excluding the circumferential central portion or in the entire region excluding the circumferential ends. The proportion of the volume of the spacer protrusion 14 in the gap can also exceed 10% over the entire region.

[0034] The difference between the proportion of the volume of the spacer protrusion 14 at the central part of the circumferential direction of the gap and the proportion of the volume of the spacer protrusion 14 at the end of the circumferential direction of the gap is less than 80%.

[0035] If the difference exceeds 80%, the difference in strength between the central part and the ends of the adhesive layer 16 in the circumferential direction may increase, and the durability of the adhesive layer 16 may decrease.

[0036] Multiple spacer protrusions 14 are formed in the same shape and are of the same size. That is, the number of spacer protrusions 14 per unit volume of the gap is greater in the circumferential central portion of the gap than in other portions. The multiple spacer protrusions 14 are spaced apart circumferentially and radially on the inner surface 13a of the support groove 13. The multiple spacer protrusions 14 are provided over the entire area of ​​the inner surface 13a of the support groove 13.

[0037] Furthermore, the number of spacer protrusions 14 per unit volume of the gap can be made equal across the entire area of ​​the gap, and the size of the spacer protrusions 14 located at the circumferential center of the gap can be larger than the size of the spacer protrusions 14 located in other parts. Alternatively, the shapes of the multiple spacer protrusions 14 can be different.

[0038] As described above, in the helical spring device 1 according to this embodiment, the proportion of the volume of the spacer protrusion 14 in the gap between the inner surface 13a of the support groove 13 and the outer peripheral surface of the wire W is larger in the circumferential central portion of the gap than in other portions. Therefore, when a vertical compressive force is applied to the main spring 11, the volume of the circumferential central portion, where the applied load is relatively low, becomes smaller in the adhesive layer 16 between the lower end of the main spring 11 and the inner surface 13a of the support groove 13. On the other hand, the volume of the circumferential end, where the applied load is relatively high, becomes larger in the adhesive layer 16, thus ensuring the strength of the circumferential end. As a result, while ensuring the adhesive strength between the lower end of the main spring 11 and the inner surface 13a of the support groove 13, the amount of adhesive used can be reduced, thereby reducing costs.

[0039] Since the multiple spacer protrusions 14 are formed in the same shape with the same size, the multiple spacer protrusions 14 can be easily formed, and the multiple spacer protrusions 14 can easily and uniformly support the outer periphery of the wire W with less deviation.

[0040] Furthermore, the technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

[0041] Furthermore, without departing from the spirit of the present invention, the structural elements of the embodiments described above may be appropriately replaced with known structural elements. In addition, the embodiments and variations described above may be appropriately combined.

[0042] Industrial applications

[0043] The present invention can be used in a helical spring device comprising: a main spring; and an insulator having a support groove provided with a plurality of spaced protrusions.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1: Helical spring device

[0046] 11: Main spring

[0047] 12: Insulator

[0048] 13: Support groove

[0049] 14: Spacing protrusion

[0050] O: Coil shaft

[0051] W: Wire

Claims

1. A helical spring device, characterized in that Possessing: a main spring whose wire spirally extends in the up-and-down direction around a coil axis; and an insulator that supports a lower end portion of the main spring from below the main spring, a support groove that extends around the coil axis and is fitted with the lower end portion of the main spring is provided in the insulator, a bonding layer is provided between the inner surface of the support groove and the lower end portion of the main spring, the lower end portion of the main spring is bonded to the inner surface of the support groove via the bonding layer, a plurality of spacing protrusions that support the outer circumferential surface of the wire are provided in the inner surface of the support groove, the support groove extends in an angular range of 180° or more and 360° or less around the coil axis, the proportion of the volume of the spacing protrusions in the gap between the inner surface of the support groove and the outer circumferential surface of the wire is greater in the central portion in the circumferential direction that extends around the coil axis in the gap than in the end portions that are other portions, the central portion in the circumferential direction of the gap refers to a portion sandwiched in the circumferential direction by portions that are 5% or more and 45% or less of the full length of the circumferential direction away from the gap on both sides of the circumferential direction with respect to the center of the circumferential direction of the gap, where the center of the circumferential direction of the gap is a portion in the gap that is equidistant from one end and the other end of the circumferential direction, in the central portion in the circumferential direction of the gap, the proportion of the volume of the spacing protrusions in the gap gradually decreases as it moves away from the center of the circumferential direction toward the circumferential direction, and the proportion of the volume of the bonding layer in the gap gradually increases as it moves away from the center of the circumferential direction toward the circumferential direction, in the end portions in the circumferential direction of the gap, the proportion of the volume of the spacing protrusions is 10% or less, and the proportion of the volume of the bonding layer is 90% or more.

2. The coil spring device according to claim 1, wherein the plurality of spacing protrusions are formed in the same shape with the same size as each other.

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