HELICAL SPRING DEVICE

Abstract

A helical spring device includes: a main body spring and an insulator (12), the insulator being provided with a support groove (13) extending around a helical axis and in which the lower end portion of the main body spring fits, the lower end portion of the main body spring adhering to an inner surface (13a) of the support groove, the inner surface of the support groove being provided with a plurality of spacer projections (14, 15) supporting an outer peripheral surface of a wire rod, a plurality of adjacent spacer projections (14) adjacent to an open end edge (21) of the support groove, each of the plurality of spacer projections including a pair of side wall surfaces (14a,14b) extending towards the open-end edge and provided at intervals (A) between them in an extension direction of the open-end edge in a plan view of a part including the open-end edge on the inner surface of the support groove, and inclination angles (θ1, θ2) of adjacent side wall surfaces to each other in the extension direction with the interval between them with respect to an orthogonal direction, orthogonal to the open-end edge, are different from each other in the plan view.

Description

HELICAL SPRING DEVICE TECHNICAL FIELD The present invention relates to a helical spring device. Priority is claimed in Japanese Patent Application No. 2020-064890, filed on March 31, 2020, the contents of which are incorporated herein by reference. PRELIMINARY TECHNIQUE A helical spring device, typically used when mounted on a suspension device, includes a main body spring with a wire rod extending vertically in a spiral around a helical axis and a housing that supports the lower end portion of the main body spring from below. The housing is provided with a support groove extending around a helical axis into which the lower end portion of the main body spring fits. This lower end portion adheres to an inner surface of the support groove, and the inner surface of the support groove is provided with a plurality of spacer projections supporting an outer peripheral surface of the wire rod. When the lower end portion of the main body spring is attached to the inner surface of the support slot, an adhesive is first placed on the inner surface of the support slot, and then the lower end portion of the main body spring is pressed into the support slot to spread the adhesive on the inner surface of the support slot. List of appointments Patent literature Patent document 1 Japanese unexamined patent application, first publication No. 201715249 Compendium of the invention Technical problem However, in the conventional coil spring device, during the process of pressing the adhesive onto the inner surface of the support groove, the lower end portion of the main body spring flows toward the open end edge of the support groove. After branching through the spacer protrusion, the flow fuses and reaches the open end edge of the support groove in a ground state. Consequently, there is a possibility of a weld line being generated and exposed on both sides of the open end edge of the support groove on the outer surface of the adhesive layer between the lower end portion of the main body spring and the inner surface of the support groove.In this case, since part of the open-end portion continues to the open-end edge on the inner surface of the support groove is exposed, there is a possibility that foreign substances, such as small stones, may enter this portion. The present invention is made in view of the circumstances described above, and an object of the present invention is to provide a helical spring device capable of suppressing the generation of a weld line on an outer surface of an adhesive layer between a lower end portion of a main body spring and an inner surface of a support groove. SOLUTION TO THE PROBLEM To solve the problems described above and achieve such an object, a helical spring device according to a first aspect of the present invention includes: a main body spring in which a wire rod extends vertically in a spiral form around a helical axis; and an insulator supporting the lower end portion of the main body spring from below the main body spring, wherein the insulator is provided with a support groove extending around the helical axis and in which the lower end portion of the main body spring fits, wherein the lower end portion of the main body spring adheres to an inner surface of the support groove, wherein the inner surface of the support groove is provided with a plurality of spacer projections supporting an outer peripheral surface of the wire rod,wherein a plurality of adjacent spacer projections, adjacent to an open-end edge of the support groove, each of the plurality of spacer projections includes a pair of side wall surfaces extending into the open-end edge and provided at intervals between them in an extension direction of the open-end edge in a plan view of a part including the open-end edge on the inner surface of the support groove, and wherein the inclination angles of the adjacent side wall surfaces to each other in the extension direction with respect to an orthogonal direction orthogonal to the open-end edge are different from each other in the plan view. According to the present invention, since the inclination angles of the adjacent side wall surfaces in the extension direction with respect to the orthogonal direction are different from each other in the plan view, for example, the direction or speed of the adhesive flow can be made different between one side wall surface and the other side wall surface defining the interval in the process in which the adhesive is placed on the opposite side of the open end edge of the support groove with the adjacent sword protrusion between them on the inner surface of the support groove flows towards the open end edge of the support groove while passing through the interval when the lower end portion of the main body spring adheres to the inner surface of the support groove.Furthermore, as the interval narrows as it approaches the open-ended edge, the momentum of the flows can weaken, causing two branch flows to interfere with each other, as one branch flow flowing along one sidewall surface splits the other branch flow flowing along the other sidewall surface at the time of merging. With the configuration described above, the adhesive flowing through the gap is prevented from reaching the open end edge of the support groove in the ground state, and it is possible to suppress the generation of the exposed weld line that extends on both sides of a portion of the open end edge of the support groove in the orthogonal direction on the outer surface of the adhesive layer between the lower end portion of the main body spring and the inner surface of the support groove. A second aspect of the present invention is a helical spring device, wherein in the helical spring device of the first aspect, at least one of the two adjacent spacer projections, adjacent to each other in the extension direction, is formed such that the width of one of the two adjacent spacer projections in the extension direction becomes narrower as it approaches the edge of the open end, and the inclination angles of the pair of side wall surfaces of one of the two adjacent spacer projections with respect to the orthogonal direction are different from each other in plan view. In this case, at least one of the two adjacent spacer projections in the extension direction is formed such that the width of one of the two adjacent spacer projections in the extension direction becomes narrower as it approaches the open end edge, and the inclination angles of the pair of side wall surfaces of one of the two adjacent spacer projections with respect to the orthogonal direction are different from each other in the plan view. Thus, when the lower end portion of the main body spring adheres to the inner surface of the support slot, the impulse of the flows can be weakened by causing two branch flows generated by the branching of a flow from the adhesive by the adjacent blade protrusion to interfere with each other, since one branch flow of the two branch flows divides the other branch flow of the two branch flows at the time of fusion, for example, in the process in which the adhesive placed on the opposite side of the open end edge of the support slot with the adjacent blade protrusion between them on the inner surface of the support slot flows to the open end edge of the support slot between the inner surface of the support slot and the outer peripheral surface of the wire forming the lower end portion of the main body spring.Consequently, two branch flows after fusion are prevented from reaching the open end edge of the support slot in the ground state, and it is possible to suppress the generation of the exposed weld line that extends on both sides of the open end edge of the support slot in the orthogonal direction, on the outer surface of the adhesive layer between the lower end portion of the main body spring and the inner surface of the support slot. A third aspect of the present invention is a helical spring device, wherein, in the helical spring device of the first or second aspect, at least one of the two adjacent spacer projections, adjacent to each other in the extension direction, is formed such that the width of one of the two adjacent spacer projections in the extension direction becomes narrower as it approaches the open end edge, and includes a front wall surface connecting end portions of the pair of side wall surfaces on the open end edge side and facing the open end edge, and an extension line intersection of the pair of side wall surfaces of one of the two adjacent spacer projections is located on the inner surface of the support groove in the plan view. In this case, when the lower end portion of the main body spring adheres to the inner surface of the support groove, two adhesive branch flows generated by the branching of an adhesive flow by the adjacent spacer protrusion, as described above, can merge at a separate position toward the rear in the flow direction from the open end edge of the support groove. Consequently, the impulse of the flows is suppressed when these two branch flows reach the open end edge of the support groove, and the generation of the weld line on the outer surface of the adhesive layer can then be reliably suppressed. A fourth aspect of the present invention is a helical spring device, wherein, in the helical spring device of any of the first to third aspects, at least one of the two intervals adjacent to each other in the extension direction becomes narrower as it approaches the open end edge, and wherein an intersection of the extension lines of the adjacent side wall surfaces in the extension direction with the interval between them in the plan view is located on the inner surface of the support groove. In this case, since the intersection of the extension lines of the adjacent side wall surfaces in the extension direction with the interval between them narrowing as it approaches the open end edge is on the inner surface of the support slot in the plan view, one adhesive flow along one side wall surface defining the interval and the other adhesive flow along the other side wall surface defining the interval can merge at a separate position on the back side in the flow direction from the open end edge of the support slot when the lower end portion of the main body spring adheres to the inner surface of the support slot.Consequently, the impulse of the flows is suppressed when these two flows reach the open end edge of the support groove, and the generation of the weld line on the outer surface of the adhesive layer can then be reliably suppressed. ADVANTAGEOUS EFFECTS OF THE INVENTION According to the present invention, it is possible to prevent a weld line from forming on an outer surface of an adhesive layer between a lower end portion of a main body spring and an inner surface of a support groove. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a helical spring device according to an embodiment of the present invention. Fig. 2 is a plan view showing a portion of the helical spring device of Fig. 1. Fig. 3 is a cross-sectional view taken through line lll-lll of the helical spring device shown in Fig. 2. Fig. 4 is a plan view of a part including an outer peripheral edge of a support groove on an inner surface of the support groove shown as a first embodiment according to the present invention. Fig. 5 is a plan view of a part including an outer peripheral edge of a support groove on an inner surface of the support groove shown as a second embodiment according to the present invention. ινΐΛ / a / zuzz / uii ai a Fig. 6 is a plan view of a part including an outer peripheral edge of a support groove on an inner surface of the support groove shown as a third embodiment according to the present invention. Fig. 7 is a plan view of a part including an outer peripheral edge of a support groove on an inner surface of the support groove shown as a fourth embodiment according to the present invention. Fig. 8 is a plan view of a part including an outer peripheral edge of a support groove on an inner surface of the support groove shown as modified examples of the first embodiment and the third embodiment according to the present invention. DESCRIPTION OF THE MODALITIES A first embodiment of a helical spring device according to the present invention is described below with reference to Figs. 1 to 4 A helical spring device 1 includes a main body spring 11 in which a wire rod W extends vertically in a spiral shape around a helical axis O and an insulator 12 that supports a lower end portion of the main body spring 11 from below. That is, the vertical direction is the direction of the helical axis O. The helical spring device 1 is used by mounting, for example, on a damper inserted in the main body spring 11 and a suspension device having a strut mount attached to the upper end of the damper. The main body spring 11 is an open-ended helical spring in which a terminated end portion w1 of wire rod W is vertically separated from the wire rod W adjacent to the terminated end portion w1 on the inside of the helical axis direction o. The cross-sectional shape of wire rod W is the same along its entire length, including the terminated end portion w1. In the example shown in the drawings, the cross-sectional shape of wire rod W is circular. Furthermore, a closed-end helical spring in which the terminated end portion w1 of wire rod W makes contact with and overlaps the wire rod W adjacent to the terminated end portion w1 on the inside of the helical axis direction O can be adopted as the main body spring 11. In this configuration, the terminated end portion w1 of wire rod W can be, for example, ground to form a flat surface extending in the horizontal direction orthogonal to the vertical direction and facing outwards in the vertical direction. The cross-sectional shape of wire rod W can be, for example, a rectangular or similar shape. ινΐΛ / a / zuzz / uii ai a Insulator 12 is made of an elastic material such as rubber. As shown in Fig. 2, insulator 12 is arc-shaped and extends around the helical axis O when viewed from the vertical direction. Insulator 12 extends over an angle range of 180° or more and 360° or less with respect to the helical axis O. The insulator 12 is provided with a support groove 13 that extends around the helical axis O and in which the lower end portion of the main body spring 11 is fitted. The support groove 13 extends over an angle range of 180° or more and 360° or less with respect to the helical axis O. As shown in Fig. 3, an adhesive layer 16 is provided between an inner surface 13a of the support groove 13 and the lower end portion of the main body spring 11, and the lower end portion of the main body spring 11 is adhered to the inner surface 13a of the support groove 13. The inner surface 13a of the support groove 13 has a concave curved shape along the outer peripheral surface of the wire rod W. The support groove 13 opens integrally to one side in the circumferential direction around the helical axis O, upwards, and outwards in the radial direction (orthogonal to the direction of the helical axis O). Additionally, such as support slot 13, for example, a configuration can be adopted in which the support slot opens towards both circumferential sides, a configuration in which the radial outside of the support slot is closed, or similar. The open-end edges 21 to 24 of the support slot 13 include an outer peripheral edge 21 that is located on the radially outer end edge of the support slot 13 and extends around the helical axis O, an inner peripheral edge 22 that is located on the radially inner end edge of the support slot 13 and extends around the helical axis O, an end edge 23 that connects the end edges in the circumferential direction of the outer peripheral edge 21 and the inner peripheral edge 22, and the other end edge 24 that extends outward in the radial direction from the other end edge in the circumferential direction of the inner peripheral edge 22. The outer peripheral edge 21 is located below the inner peripheral edge 22. An end edge 23 has a concave curved shape along the outer peripheral surface of the wire rod W when viewed from the side in the circumferential direction. ινΐΛ / a / zuzz / uii ai a The inner surface 13a of the support groove 13 is provided with a plurality of spacer projections 14 and 15 that support the outer peripheral surface of the wire rod W. The plurality of spacer protrusions 14 and 15 are provided on the inner surface 13a of the support groove 13 at intervals between them in the circumferential and radial directions. The plurality of spacer protrusions 14 and 15 are provided across the entire area of ​​the inner surface 13a of the support groove 13. The ratio of the volume of the spacer protrusions 14 and 15 occupying a gap between the inner surface 13a of the support groove 13 and the outer peripheral surface of the wire rod W exceeds 10%, and the ratio of the volume of the adhesive layer 16 occupying the gap is less than 90%. As shown in Fig. 4, the adjacent sword-like protrusion 14, which is adjacent to the open-end edge 21 to 24 of the support slot 13, of the plurality of spacer protrusions 14 and 15 includes a pair of side-wall surfaces 14a and 14b extending into the open-end edges 21 to 24. In the example shown in the drawing, the adjacent sword-like protrusion 14 is adjacent to the outer peripheral edge 21 of the support slot 13, and the pair of side-wall surfaces 14a and 14b of the adjacent sword-like protrusion 14 extends to the outer peripheral edge 21 of the support slot 13. Furthermore, as the adjacent spacing protrusion 14, a configuration may be adopted in which the side wall surfaces 14a and 14b of the adjacent spacing protrusion 14 extend to the other open-end edges 22 to 24 of the support groove 13, being adjacent to the other open-end edge 22 to 24 other than the outer peripheral edge 21 and the open-end edge 21 to 24 of the support groove 13. In the plurality of spacing protrusions 14 and 15, the spacing protrusion 15 distinct from the adjacent spacing protrusion 14 may be formed, for example, in a column or similar shape that does not include the pair of side wall surfaces 14a and 14b. As shown in figs. 4, a plurality of adjacent blade projections 14 are provided at intervals A in the extension direction of the outer peripheral edge 21 of the support groove 13 in the plan view (in a view in the direction of the helical axis O) of the part including the outer peripheral edge 21 of the support groove 13 on the inner surface 13a of the support groove 13. In the example shown in the drawing, the extension direction is the same as the circumferential direction. Then at least one of the two adjacent spacer projections 14 adjacent to each other in the circumferential direction is formed so that the width of one of the two adjacent spacer projections 14 in the circumferential direction becomes narrower as it approaches the outer peripheral edge 21 of the support slot 13 and the tilt angles Θ1 and Θ2 of the pair of side wall surfaces 14a and 14b of the two adjacent spacer projections 14 with respect to the orthogonal direction, orthogonal to the outer peripheral edge 21 of the support slot 13 in the plan view are different from each other. In the example shown in the drawing, the orthogonal direction is the same as the radial direction. Furthermore, at least one of the two adjacent spacer projections 14, adjacent to each other in the circumferential direction, is formed such that the circumferential width of one of the two adjacent spacer projections 14 becomes narrower as it approaches the outer peripheral edge 21 of the support slot 13, and includes a front wall surface 14c connecting the end portions of the pair of side wall surfaces 14a and 14b on the side of the outer peripheral edge 21 of the support slot 13 and opposite the outer peripheral edge 21 of the support slot 13, and an intersection P1 of the extension lines L1 and L2 of the pair of side wall surfaces 14a and 14b lies on the inner surface 13a of the support slot 13 in the plan view. That is, the intersection P1 is located between the front wall surface 14c and the outer peripheral edge 21 of the support slot 13.Additionally, in the plan view, intersection P1 can be located outside of support slot 13. In the example shown in the drawing, the plurality of adjacent spacer protrusions 14 are formed to have the same size and shape. The adjacent spacer projection 14 has a trapezoidal shape in which the front wall surface 14c forms a top base and the pair of side wall surfaces 14a and 14b form the feet in the plan view. In the plan view, one side wall surface 14a of the pair of side wall surfaces 14a and 14b of each adjacent spacer projection 14 extends in a direction in which one side wall surface 14a becomes closer to the other side wall surface 14b of the pair of side wall surfaces 14a and 14b as it approaches the outer peripheral edge 21 of the support slot 13, and the other side wall surface 14b extends in a direction in which the other side wall surface 14b moves away from one side wall surface 14a as it approaches the outer peripheral edge 21 of the support slot 13. Furthermore, the pair of side wall surfaces 14a and 14b of each adjacent sword-like protrusion 14 can be extended in a direction in which the side wall surfaces 14a and 14b approach each other in the circumferential direction a ινΐΛ / a / zuzz / uii ai as they approach the outer peripheral edge 21 of the support slot 13 in the plan view. In the plan view, the inclination angles 01 and 02 of the adjacent side wall surfaces 14a and 14b in the circumferential direction, with the interval A between them, are different with respect to the radial direction. The width of the interval A (the size in the circumferential direction) becomes wider as it approaches the outer peripheral edge 21 of the support groove 13. The pair of side wall surfaces 14a and 14b extend straight in the plan view. As described above, according to the helical spring device 1 of this modality, the inclination angles Θ1 and Θ2 of the adjacent side wall surfaces 14a and 14b in the circumferential direction with the interval A between them with respect to the radial direction in the plan view are different. Thus, when the lower end portion of the main body spring 11 adheres to the inner surface 13a of the support groove 13, for example, the direction or speed of the adhesive flows can be made different between one side of the side wall surface 14a and one side of the other side wall surface 14b by defining interval A in the process in which the adhesive placed on the opposite side of the outer peripheral edge 21 of the support groove 13 with the adjacent sword-like protrusion 14 between them on the inner surface 13a of the support groove 13 flows towards the outer peripheral edge 21 of the support groove 13 while passing through interval A. Consequently, the adhesive flowing through interval A is prevented from reaching the outer peripheral edge 21 of the support groove 13 in a ground state, and it is possible to suppress the generation of the weld line on the outer surface of the adhesive layer 16 between the lower end portion of the main body spring 11 and the inner surface 13a of the support groove 13. In this embodiment, at least one of two adjacent spacer projections 14 adjacent to each other in the circumferential direction is formed so that the width of one of the two adjacent spacer projections 14 becomes narrower as it approaches the outer peripheral edge 21 of the support groove 13 and the tilt angles Θ1 and Θ2 of the pair of side wall surfaces 14a and 14b of the two adjacent spacer projections 14 with respect to the radial direction are different from each other in the plan view. Thus, when the lower end portion of the main body spring 11 adheres to the inner surface 13a of the support groove 13, the impulse of the flows can be weakened by causing two branch flows, which are generated by branching a flow through the adjacent sword protrusion 14, to interfere with each other when one branch flow of the two branch flows divides the other branch flow of the two branch flows at the time of fusion, for example, in the process in which the adhesive placed on the opposite side of the outer peripheral edge 21 of the support groove 13 with the adjacent sword protrusion 14 between them on the inner surface 13a of the support groove 13 flows to the outer peripheral edge 21 of the support groove 13 between the inner surface 13a of the support groove 13 and the outer peripheral surface of the wire rod W forming the lower end portion of the body spring main 11.Consequently, two branch flows that merge after fusion are suppressed so that they do not reach the outer peripheral edge 21 of the support groove 13 in the ground state, and it is possible to suppress the generation of the weld line by exposing a portion of the outer peripheral edge 21 of the support groove 13 straddling in the radial direction, on the outer surface of the adhesive layer 16 between the lower end portion of the main body spring 11 and the inner surface 13a of the support groove 13. In this embodiment, at least one of two adjacent spacer projections 14 adjacent to each other in the circumferential direction is formed so that the width of one of the two adjacent spacer projections 14 becomes narrower as it approaches the outer peripheral edge 21 of the support slot 13, and includes the front wall surface 14c connecting the end portions of the pair of side wall surfaces 14a and 14b on the side of the outer peripheral edge 21 of the support slot 13 and opposite the outer peripheral edge 21 of the support slot 13, and the intersection P1 between the extension lines L1 and L2 of the pair of side wall surfaces 14a and 14b are located on the inner surface 13a of the support slot 13 in the plan view. Thus, when the lower end portion of the main body spring 11 adheres to the inner surface 13a of the support groove 13, two adhesive branch flows generated by the branching flow from the adjacent blade protrusion 14, as described above, can merge at separate positions toward the rear in the flow direction from the outer peripheral edge 21 of the support groove 13 (a separate position for the inner flow radially from the outer peripheral edge 21). Consequently, the impulse of the flows is suppressed when these two branch flows reach the outer peripheral edge 21 of the support groove 13, and the generation of the weld line on the outer surface of the adhesive layer 16 can be reliably suppressed. A helical spring device 2 according to a second embodiment of the present invention is described below with reference to Fig. 5. ινΐΛ / a / zuzz / uii ai a Furthermore, in the second modality, the same parts as the components of the first modality are designated with the same reference numbers, their description is omitted and only the different points are described. In the helical spring device 2 of this embodiment, at least one of the two circumferentially adjacent intervals A becomes narrower as it approaches the outer peripheral edge 21 of the support slot 13, and in plan view, an intersection P2 of the extension lines L2 of the circumferentially adjacent side wall surfaces 14b with the interval A between them is located on the inner surface 13a of the support slot 13. That is, the intersection P2 is located between the outer peripheral edge 21 of the support slot 13 and the front wall surface 14c. In the example shown in the drawing, the adjacent spacer projections 14, adjacent to each other in the circumferential direction, are symmetrical with respect to a line extending radially through the central portion in the circumferential direction at interval A in the plan view. In the plan view, the inclination angles Θ1 of the adjacent side wall surfaces 14a, adjacent to each other in the circumferential direction with interval A between them, with respect to the radial direction, are equal to each other, and the inclination angles D2 of the adjacent side wall surfaces 14b, adjacent to each other in the circumferential direction with interval A between them, with respect to the radial direction, are also equal to each other.The interval A, in which its width narrows as it approaches the outer peripheral edge 21 of the support slot 13, and the interval A, in which its width widens as it approaches the outer peripheral edge 21 of the support slot 13, are provided alternately in the circumferential direction with the adjacent spacer protrusion 14 between them. In the plan view, the intersection P2 of the extension lines L2 of the side wall surfaces 14b that define the former interval A (interval A having a width that narrows as it approaches the outer peripheral edge 21 of the support slot 13) lies on the inner surface 13a of the support slot 13. The intersection P2 coincides with the intersection P1 of each of the adjacent spacer protrusions 14, sandwiching the former interval A in the circumferential direction in the plan view. Additionally, in the plan view, intersection P2 can be located outside the support slot 13 or it can be located far from intersection P1. Furthermore, the inclination angles Θ1 of adjacent side wall surfaces 14a in the circumferential direction with the interval A between them with respect to the radial direction can be different from each other in the plan view, and the inclination angles C2 of adjacent side wall surfaces 14b in the circumferential direction with the interval A between them with respect to the radial direction can be different from each other in the plan view. As described above, according to the helical spring device 2 of this modality, the intersection P2 of the extension lines L2 of the adjacent side wall surfaces 14b in the circumferential direction with the interval A, becoming narrower as it approaches the outer peripheral edge 21 of the support slot 13, between them lies on the inner surface 13a of the support slot 13 in the plan view.Consequently, when the lower end portion of the main body spring 11 adheres to the inner surface 13a of the support groove 13, one adhesive flow along a side wall surface 14b defining interval A and the other adhesive flow along the other side wall surface 14b defining interval A can merge at a separate position toward the rear in the flow direction from the outer peripheral edge 21 of the support groove 13 (a separate position inward in the radial direction of the outer peripheral edge 21). This suppresses the impulse of the flows when these two flows reach the outer peripheral edge 21 of the support groove 13 and reliably prevents the formation of a weld line on the outer surface of the adhesive layer 16. A helical spring device 3 is described below according to a third embodiment of the present invention with reference to Fig. 6. Furthermore, in the third modality, the same parts as the components of the first modality are designated with the same reference numbers, their description is omitted and only the different points are described. In the helical spring device 3 of this embodiment, the adjacent blade protrusion 14 does not include the front wall surface 14c and has a sharp triangular shape toward the outer peripheral edge 21 of the support slot 13 in the plan view. In the example shown in the drawing, the pair of side wall surfaces 14a and 14b of each adjacent blade protrusion 14 extend in a direction such that the pair of side wall surfaces 14a and 14b approach each other in the circumferential direction as it approaches the outer peripheral edge 21 of the support slot 13 in the plan view. As described above, according to the helical spring device 3 of this modality, the operation and effect are almost the same as those of the helical spring device 1 of the first modality. ινΐΛ / a / zuzz / uii ai a A helical spring device 4 is described below with reference to Fig. 7, according to a fourth embodiment of the present invention. Furthermore, in the fourth modality, the same parts as the components of the first modality are designated with the same reference numbers, their description is omitted and only the different points are described. In the helical spring device 4 of this modality, the inclination angles Θ1 and Θ2 of the adjacent side wall surfaces 14a and 14b in the circumferential direction with the interval A between them with respect to the radial direction are different from each other in the plan view. The inclination angles Θ1 or Θ2 of the pair of side wall surfaces 14a and 14b of each adjacent spacer projection 14 with respect to the radial direction are equal to each other in the plan view. In the example shown in the drawing, the adjacent spacer projection 14 has the shape of a parallel quadrilateral in the plan view. Furthermore, the planar shape of the adjacent spacer protrusion 14 is not limited to a parallel quadrilateral shape and can be changed accordingly. Additionally, the inclination angles Θ1 or Θ2 of the pair of side wall surfaces 14a and 14b of each adjacent spacer protrusion 14 with respect to the radial direction can differ from each other in plan view. At least one of the two adjacent intervals A in the circumferential direction narrows as it approaches the outer peripheral edge 21 of the support slot 13. In the example shown in the drawing, the interval A in which its width narrows as it approaches the outer peripheral edge 21 of the support slot 13 and the interval A in which its width widens as it approaches the outer peripheral edge 21 of the support slot 13 are provided alternately in the circumferential direction with the adjacent sword-like protrusion 14 between them. In the plan view, the intersection P2 of the extension lines L1 and L2 of the side wall surfaces 14a and 14b that define the former interval A lies on the inner surface 13a of the support slot 13.That is, the intersection P2 is located between the outer peripheral edge 21 of the support slot 13 and the surface of the front wall 14c. Additionally, the intersection P2 can be located on the outside of the support slot 13 in the plan view. As described above, according to the helical spring device 4 of this modality, the inclination angles Θ1 and Θ2 of the adjacent side wall surfaces 14a and 14b in the circumferential direction with the interval A between them with respect to the radial direction are different from each other in the plan view. ινΐΛ / a / zuzz / uii ai a Thus, when the lower end portion of the main body spring 11 adheres to the inner surface 13a of the support groove 13, for example, the direction or speed of the adhesive flows can be made different between one side of the sidewall surface 14a and one side of the other sidewall surface 14b, defining the interval A in the process where the adhesive on the inner surface 13a of the support groove 13 flows towards the outer peripheral edge 21 of the support groove 13 as it passes through interval A. Furthermore, when interval A becomes narrower as it approaches the outer peripheral edge 21 of the support groove 13, the momentum of the flows can be weakened by causing two branch flows to interfere with each other, such as a branch flow flowing along one sidewall surface 14a splitting the flow of the other branch flowing along the other sidewall surface 14b at the moment of fusion. With the configuration described above, the adhesive flowing through interval A is prevented from reaching the outer peripheral edge 21 of the support groove 13 in the ground state, and the generation of the weld line on the outer surface of the adhesive layer 16 can be suppressed. Since the intersection P2 of the extension lines L1 and L2 of the adjacent side wall surfaces 14a and 14b in the circumferential direction with the interval A, narrowing as it approaches the outer peripheral edge 21 of the support slot 13, between them is located on the inner surface 13a of the support slot 13 in the plan view, one adhesive flow flows along one side wall surface 14a defining the interval A and the other adhesive flow flows along the other side wall surface 14b defining the interval A may merge at a separate position towards the back side in the flow direction from the outer peripheral edge 21 of the support slot 13 (a separate position towards the inside in the radial direction from the outer peripheral edge 21) when the lower end portion of the main body spring 11 adheres to the inner surface 13a of the support slot 13.Consequently, the impulse of the flows is suppressed when these two flows reach the outer peripheral edge 21 of the support groove 13 and the generation of the weld line on the outer surface of the adhesive layer 16 can be reliably suppressed. Additionally, the technical scope of the present invention is not limited to the modalities described above, and various modifications can be made without departing from the object of the present invention. For example, the pair of side wall surfaces 14a and 14b may be curved in plan view and the flat shape of the adjacent spacer projection 14 may have a chamfered corner shape, an oval shape or similar. ινΐΛ / a / zuzz / uii ai a The adjacent sword-like protrusion 14 can be provided over the entire length of the inner surface 13a of the support groove 13 in the radial direction. In the first or third mode, for example, as shown in Fig. 8, one of the two adjacent spacer projections 14, adjacent to each other in the circumferential direction, can be provided in a rotatable direction about the center of the figure by 180° in the plan view so that the width of the two adjacent spacer projections 14 widens as it approaches the outer peripheral edge 21 of the support groove 13. In this case, the side wall surfaces 14a adjacent to each other in the circumferential direction with the interval A between them can be made parallel to each other in the plan view, and the side wall surfaces 14b adjacent to each other in the circumferential direction with the interval A between them can be made parallel to each other in the plan view.Furthermore, in this case, the inclination angles Θ1 of the side wall surfaces 14a with the interval A between them with respect to the radial direction can be equal to each other, and the inclination angles U2 of the side wall surfaces 14b with the interval A between them with respect to the radial direction can be equal to each other. Furthermore, the constituent elements in the embodiment described above can be appropriately replaced with well-known constituent elements without departing from the objective of the present invention, and the embodiments described above and the modified example can be appropriately combined. Industrial applicability The present invention can be used in a helical spring device comprising a main body spring and an insulator comprising a support slot provided with a plurality of spacer protrusions.

Claims

CLAIMS 1. A helical spring device characterized in that it comprises: a main body spring in which a wire rod extends vertically in a spiral form around a helical axis; and an insulator supporting a lower end portion of the main body spring from below the main body spring, wherein the insulator is provided with a support groove extending around the helical axis and in which the lower end portion of the main body spring fits, wherein the lower end portion of the main body spring adheres to an inner surface of the support groove, wherein the inner surface of the support groove is provided with a plurality of spacer projections supporting an outer peripheral surface of the wire rod, wherein a plurality of adjacent spacer projections,adjacent to an open-end edge of the support slot of the plurality of spacer projections, each including a pair of side wall surfaces extending into the open-end edge and provided at intervals between them in an extension direction of the open-end edge in a plan view of a part including the open-end edge on the inner surface of the support slot, and wherein the inclination angles of the adjacent side wall surfaces in the extension direction with respect to an orthogonal direction, orthogonal to the open-end edge, are different from each other in the plan view.

2. The helical spring device according to claim 1, characterized in that at least one of the two adjacent spacer projections, adjacent to each other in the extension direction, is formed such that the width of one of the two adjacent spacer projections in the extension direction narrows as it approaches the open end edge and the inclination angles of the pair of side wall surfaces of the two adjacent spacer projections with respect to the orthogonal direction are different from each other in plan view.

3. The helical spring device according to claim 1 or 2, characterized in that at least one of the two adjacent spacer projections, adjacent to each other in the extension direction, is formed such that the width of one of the two adjacent spacer projections in the extension direction becomes narrower as it approaches the open end edge, and includes a front wall surface connecting end portions of the pair of side wall surfaces on the side of the open end edge and facing the open end edge, and an intersection of extension lines of the pair of side wall surfaces of one of the two adjacent spacer projections is located on the inner surface of the groove of the support in the plan view.

4. The helical spring device according to any of claims 1 to 3, characterized in that at least one of the two adjacent intervals in the extension direction becomes narrower as it approaches the edge of the open end, and wherein an intersection of the extension lines of the adjacent side wall surfaces in the extension direction with the interval between them in the plan view is located on the inner surface of the support groove.

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