JP2013253665A - Spring assembly - Google Patents

Abstract

An object of the present invention is to provide a spring assembly that can be easily assembled without cost while preventing an inner coil spring from falling off during use.
An outer coil spring, an inner coil spring disposed inside the outer coil spring, a fixing member for fixing the outer coil spring and the inner coil spring at predetermined portions 2c and 3b. The fixing member 5 includes a gap between the windings of both the outer coil spring 2 and the inner coil spring 3 when viewed from a direction perpendicular to the winding center axis direction 10 of the outer coil spring 2 and the inner coil spring 3. And are fitted into predetermined portions 2c and 3b disposed in the middle of the inner coil spring 3 continuous in the winding center axis direction 10.
[Selection] Figure 1

Description

  The present invention relates to a spring assembly in which a plurality of types of coil springs are combined.

  The torque fluctuation absorber disposed on the power transmission path between the engine and the transmission has a damper portion that absorbs (suppresses) the fluctuation torque generated between the engine and the transmission by an elastic force, In the damper portion, a coil spring is arranged between the circumferential directions of the two rotating members. The damper portion absorbs the fluctuation torque by contraction of the coil spring when the two rotating members rotate relative to each other. In the damper portion, a spring assembly in which a plurality of types of coil springs are combined may be used in order to ensure torque capacity.

  For example, in Patent Document 1, an inner coil spring (9 in FIG. 2 of Patent Document 1) is arranged inside an outer coil spring (8 in FIG. 2 of Patent Document 1), and a part of the inner coil is formed in an elliptical shape. In addition, there is disclosed a method in which the swelled portion of the elliptical shape is fitted in a gap between windings of an outer coil spring.

  Patent Document 2 discloses a structure in which a ring-shaped spacer (15 of Patent Document 2) is fitted between an outer coil spring (1 of Patent Document 2) and an inner coil spring (2 of Patent Document 2). Has been.

JP 11-311296 A European Patent No. 1927781

  The following analysis is given by the inventor.

  However, since the fitting allowance cannot be increased in the configuration as in Patent Document 1, the inner coil spring may come off during use. Moreover, in a structure like patent document 1, it is necessary to press-fit and assemble an inner coil spring in the state which contact | attached the outer coil spring, and the installation for exclusive use for carrying out rotation compression is needed. Furthermore, since the inner coil spring is wound into an ellipse, the manufacturing time is increased and the cost is increased.

  Further, even with the configuration as in Patent Document 2, since the fitting allowance cannot be increased, the inner coil spring may come off during use. Further, even in the configuration as in Patent Document 2, it is necessary to press-fit the inner coil spring in a state where the outer coil spring is in close contact, and a dedicated facility for rotational compression is required. Furthermore, in order to fit the ring-shaped spacer between the outer coil spring and the inner coil spring, it is necessary to bring the outer coil spring and the inner coil spring into close contact with each other at the same time. Is difficult.

  The main subject of this invention is providing the spring assembly which can perform an assembly operation | work easily, without incurring cost, preventing an inner coil spring falling off during use.

  In one aspect of the present invention, in a spring assembly, an outer coil spring, an inner coil spring disposed inside the outer coil spring, and the outer coil spring and the inner coil spring are fixed at predetermined portions. A fixing member, and the fixing member is between the windings of both the outer coil spring and the inner coil spring when viewed from a direction perpendicular to the winding center axis direction of the outer coil spring and the inner coil spring. And are fitted into the predetermined portion disposed in the middle of the inner coil spring that is continuous in the winding central axis direction.

  In the spring assembly of the present invention, the fixing member may be fitted so that the windings of both the outer coil spring and the inner coil spring are in contact with each other when the outer coil spring and the inner coil spring are compressed. preferable.

  In the spring assembly of the present invention, it is preferable that the fixing member is sandwiched between one or both windings of the outer coil spring and the inner coil spring with a preload.

  In the spring assembly of the present invention, it is preferable that the fixing member has a recess corresponding to the shape of the predetermined portion of one or both of the outer coil spring and the inner coil spring.

  In the spring assembly according to the present invention, the fixing member may be disposed on one or both of the winding center axis direction at a portion between the outer coil spring and the inner coil spring in a direction perpendicular to the winding center axis direction. It is preferable to have a protruding portion that protrudes.

  In the spring assembly according to the present invention, it is preferable that the fixing member has a taper portion formed so as to become thinner as it goes to a tip portion in a portion extending inward than the inner coil spring.

  In the spring assembly according to the present invention, it is preferable that the fixing member is formed using a thin metal plate and has a hook portion configured to be hooked on an inner surface of the inner coil spring.

  In the spring assembly according to the aspect of the invention, it is preferable that the hook portion can be bent so as to pass through the predetermined portions of the outer coil spring and the inner coil spring.

  In the spring assembly according to the aspect of the invention, it is preferable that the fixing member has a cut portion that can be deformed in accordance with the shapes of the predetermined portions of the outer coil spring and the inner coil spring.

  In the spring assembly of the present invention, the predetermined portion starts to open a gap between lines first from the end portions of the outer coil spring and the inner coil spring in a free state of the outer coil spring and the inner coil spring. It is preferably between the windings.

  According to the present invention, the fixing member as a separate member is fitted into a predetermined portion of the outer coil spring and the inner coil spring, so that the outer coil spring and the inner coil spring in the direction of the winding center axis of the outer coil spring and the inner coil spring during use. Coil springs do not fall out. In addition, since the fixing member is inserted into the outer coil spring and the inner coil spring from the direction perpendicular to the winding central axis direction (radial direction), the outer coil spring and the inner coil spring are fixed without compressing the coil spring. As a result, it is possible to easily perform the assembling work and to eliminate the need for large facilities and jigs for the assembling work as in the prior art, so that the cost can be reduced.

It is sectional drawing of the winding center axis direction which showed typically the structure of the spring assembly which concerns on Example 1 of this invention. It is sectional drawing between (A) XX 'which showed typically the structure of the fixing member used for the spring assembly which concerns on Example 1 of this invention, (B) Plan view, (C) Perspective view. It is the fragmentary sectional view of the winding center axis direction which showed the assembly process of the spring assembly concerning Example 1 of the present invention typically, (A) before attachment of a fixing member, (B) after attachment of a fixing member. . It is sectional drawing which showed typically the structure of the fixing member used for the spring assembly which concerns on Example 2 of this invention. It is the (A) top view which showed typically the structure of the fixing member used for the spring assembly which concerns on Example 3 of this invention, (B) It is sectional drawing between XX '. It is a fragmentary sectional view of the direction of a winding central axis which showed typically the composition of the spring assembly concerning Example 3 of the present invention.

[Outline of Embodiment]
In the spring assembly according to the embodiment of the present invention, an outer coil spring (2 in FIG. 1), an inner coil spring (3 in FIG. 1) disposed inside the outer coil spring, the outer coil spring, and the A fixing member (5 in FIG. 1) for fixing the inner coil spring at a predetermined portion (2c, 3b in FIG. 1), and the fixing member is a winding center axis of the outer coil spring and the inner coil spring. When viewed from a direction perpendicular to the direction (10 in FIG. 1), the inner coil spring in which a gap between the windings of both the outer coil spring and the inner coil spring overlaps and is continuous in the winding central axis direction. It is inserted into the predetermined part arranged in the middle of.

  Note that, in the present application, where reference numerals are attached to the drawings, these are only for the purpose of helping understanding, and are not intended to be limited to the illustrated embodiments. Hereinafter, embodiments will be described with reference to the drawings.

  A spring assembly according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view in the winding central axis direction schematically showing the configuration of the spring assembly according to the first embodiment of the present invention. 2A and 2B schematically show the structure of the fixing member used in the spring assembly according to the first embodiment of the present invention. FIG. 2A is a cross-sectional view taken along the line XX ′, FIG. 2B is a plan view, and FIG. FIG. FIG. 3 is a partial cross-sectional view schematically showing the assembly process of the spring assembly according to the first embodiment of the present invention in the winding central axis direction, (A) before attaching the fixing member, (B) of the fixing member. After installation. FIG. 1 is a view when the coil springs 2, 3, 4 are in a free state.

  Referring to FIG. 1, a spring assembly 1 is an assembly in which a plurality of types (three types in FIG. 1) of coil springs 2, 3, and 4 are combined. The spring assembly 1 shown in FIG. 1 is used for a damper portion of a torque fluctuation absorber that absorbs (suppresses) fluctuation torque generated between an engine and a transmission by an elastic force, but is also used for other applications. be able to. The spring assembly 1 has a configuration in which inner coil springs 3 and 4 are disposed inside an outer coil spring 2. The spring assembly 1 uses, for example, coil springs 2, 3, 4 having different lengths in the winding center axis direction 10 (compression direction) as shown in FIG. 1 so that the spring load (spring characteristics) changes in multiple stages. Or a coil spring (not shown) having the same length in the winding center axis direction 10 can be used to enhance the spring load. The spring assembly 1 includes an outer coil spring 2, an inner coil spring 3, an inner coil spring 4, a fixing member 5, and a fixing member 6 as constituent members.

  The outer coil spring 2 is a coil spring disposed outside the inner coil springs 3 and 4 (see FIG. 1). The outer coil spring 2 has an arc shape (arc shape) in the winding center axis direction 10. The outer coil spring 2 is used so as to expand and contract in the winding center axis direction 10. The outer coil spring 2 is arranged so that the inner coil spring 3 is aligned with the end 2a so that the end 3a of the inner coil spring 3 is aligned with the end 2a, and the end 4a of the inner coil spring 4 is aligned with the end 2b. An inner coil spring 4 is arranged. The length of the outer coil spring 2 (length in the winding center axis direction 10) is set longer than the total length of the inner coil springs 3 and 4 (length in the winding center axis direction 10). The winding direction of the outer coil spring 2 is opposite to the winding direction of the inner coil spring 3. The outer coil spring 2 has an outer recess (5a in FIG. 2) in the gap between the first windings from the end 2a (the gap between the windings that first starts to open from the end 2a in the free state). 5b) has a fitting portion 2c for fitting. The outer coil spring 2 has an outer recess (5a in FIG. 2) in the gap between the first windings from the end 2b (the gap between the windings that first starts to open from the end 2b in the free state). 5d) and a fitting portion 2d for fitting into the same.

  The inner coil spring 3 is a coil spring disposed inside the outer coil spring 2 (see FIG. 1). The inner coil spring 3 has an arc shape (arc shape) in the winding center axis direction 10. The inner coil spring 3 is used so as to expand and contract in the winding center axis direction 10. The outer coil spring 2 is arranged on the outer side of the inner coil spring 3 so that the end portion 2a of the outer coil spring 2 is aligned with the end portion 3a. The length of the inner coil spring 3 (length in the winding center axis direction 10) is set shorter than the length of the outer coil spring 2 (length in the winding center axis direction 10). The winding direction of the inner coil spring 3 is opposite to the winding direction of the outer coil spring 2. The inner coil spring 3 is separated from the inner coil spring 4 until the outer coil spring 2 is compressed to a predetermined length from the free state, and when the outer coil spring 2 is compressed to a predetermined length, the inner coil spring 4 contacts the inner coil spring 4. The outer coil spring 2 is compressed when the outer coil spring 2 is compressed further than a predetermined length. The inner coil spring 3 has an inner recess (5c in FIG. 2) in the gap between the second windings from the end 3a (the gap between the windings that first starts to open from the end 3a in the free state). 5d) has a fitting portion 3b for fitting.

  The inner coil spring 4 is a coil spring disposed inside the outer coil spring 2 (see FIG. 1). The inner coil spring 4 has an arc shape (arc shape) in the winding center axis direction 10. The inner coil spring 4 is used so as to expand and contract in the winding center axis direction 10. The outer coil spring 2 is disposed on the outer side of the inner coil spring 4 so that the end portion 2b of the outer coil spring 2 is aligned with the end portion 4a. The length of the inner coil spring 4 (length in the winding center axis direction 10) is set shorter than the length of the outer coil spring 2 (length in the winding center axis direction 10). The winding direction of the inner coil spring 4 is opposite to the winding direction of the outer coil spring 2. The inner coil spring 4 is separated from the inner coil spring 3 until the outer coil spring 2 is compressed to a predetermined length from the free state, and when the outer coil spring 2 is compressed to a predetermined length, the inner coil spring 3 contacts with the inner coil spring 3. The outer coil spring 2 is compressed when the outer coil spring 2 is compressed further than a predetermined length. The inner coil spring 4 has an inner recess (5c in FIG. 2) in the gap between the first windings from the end 4a (the gap between the windings that first starts to open from the end 4a in the free state). It has a fitting part 4b for fitting into the same as 5d.

  The fixing member 5 is a member that fixes predetermined portions (the fitting portions 2c and 3b in FIG. 1) of the outer coil spring 2 and the inner coil spring 3 (see FIG. 1). The fixing member 5 has a gap between the windings of both the outer coil spring 2 and the inner coil spring 3 when viewed from a direction perpendicular to the winding center axis direction 10 (radial direction). Are inserted into predetermined portions (the fitting portions 2c and 3b) disposed in the middle of the inner coil spring 3 that is continuous with the inner coil spring 3. The fixing member 5 is fitted so that a portion between the windings (the fitting portions 2c and 3b) of the outer coil spring 2 and the inner coil spring 3 comes into contact during compression. The fixing member 5 is sandwiched between the fitting portions 2c and 3b of the outer coil spring 2 and the inner coil spring 3 (which may be one fitting portion) with a preload. By applying the preload, it is possible to prevent the fixing member 5 from being worn or pulled out due to rattling of the fixing member 5. The fixing member 5 is formed in a fan shape and a plate shape. As a material for the fixing member 5, a metal can be used to ensure strength, and a resin can be used for ease of manufacturing and weight reduction. Further, the fixing member 5 can be made by sintering or forging in order to make the shape easy. The fixing member 5 includes outer concave portions 5a and 5b, inner concave portions 5c and 5d, convex portions 5e and 5f, and a tapered portion 5g as constituent parts (see FIG. 2).

  The outer recessed portion 5a has a portion on the end portion 2a side of the fitting portion 2c of the outer coil spring 2 on one surface of the fixing member 5 (surface viewed from the end portion 2a side of the outer coil spring 2 in the winding center axis direction 10). It is a recessed part for fitting. The outer concave portion 5b is formed by disposing a portion on the end 2b side of the fitting portion 2c of the outer coil spring 2 on the other surface of the fixing member 5 (a surface viewed from the end 2b side of the outer coil spring 2 in the winding center axis direction 10). It is a recessed part for fitting. The outer recesses 5a and 5b preferably correspond to the shape of the fitting portion 2c of the outer coil spring 2.

  The inner concave portion 5 c is a concave portion for fitting a portion on the end 3 a side of the fitting portion 3 b of the inner coil spring 3 into one surface of the fixing member 5. The inner concave portion 5 d is a concave portion for fitting a portion of the inner coil spring 3 opposite to the end portion 3 a side into the other surface of the fixing member 5. The inner recesses 5 c and 5 d preferably correspond to the shape of the fitting portion 3 b of the inner coil spring 3.

  The convex portions 5e and 5f are for preventing the fixing member 5 from coming off from the fitting portions 2c and 3b of the outer coil spring 2 and the inner coil spring 3. The convex portion 5 e is a convex portion formed in a portion between the outer concave portion 5 a and the inner concave portion 5 c on one surface of the fixing member 5, and the fitting portion 2 c of the outer coil spring 2 and the fitting portion of the inner coil spring 3. It is inserted into a recess formed between 3b. The convex portion 5 f is a convex portion formed in a portion between the outer concave portion 5 b and the inner concave portion 5 d on the other surface of the fixing member 5, and the fitting portion 2 c of the outer coil spring 2 and the fitting portion of the inner coil spring 3. It is inserted into a recess formed between 3b.

  The taper portion 5g is configured so that the gap between the windings of the outer coil spring 2 and the inner coil spring 3 overlaps the fixing member 5 from the direction perpendicular to the winding center axis direction 10 (radial direction), and the winding center. A portion having a tapered surface for facilitating insertion into a predetermined portion (the fitting portions 2c and 3b) disposed in the middle of the inner coil spring 3 continuous in the axial direction 10, and becomes thinner as it goes to the tip portion. It is formed as follows.

  As shown in FIG. 3, the fixing member 5 can be inserted and fitted into the fitting portions 2 c and 3 b from the outside of the arc-shaped coil springs 2 and 3. In this case, even when the inner peripheral portions of the coil springs 2 and 3 are in close contact with each other, a gap remains between the windings in the outer peripheral portion, so that a large contact margin can be ensured. Although not shown, the fixing member 5 may be inserted and fitted into the fitting portions 2c and 3b from the inside of the arc-shaped coil springs 2 and 3. In this case, since the fixing member is fixed between the windings when the windings in the inner peripheral portion are in close contact with each other, the adhesion strength is strong. Although not shown, the fixing member 5 may be inserted into the fitting portions 2c and 3b from the lateral sides of the arcuate coil springs 2 and 3 and fitted. In this case, the fixing member 5 can be easily inserted.

  The fixing member 6 is a member for fixing predetermined portions (the end portions 2b and 4a in FIG. 1) of the outer coil spring 2 and the inner coil spring 4 to each other (see FIG. 1). The configuration of the fixing member 6 is the same as the configuration of the fixing member 5.

  According to the first embodiment, the fixing member 5 (6), which is a separate member, is fitted into the gap between the windings of the coil springs 2, 3 (2, 4) (the fitting portions 2c, 3b (2d, 4b)). During use, the coil springs 2, 3 (2, 4) do not fall out in the winding center axis direction 10 of the coil springs 2, 3 (2, 4). Further, since the fixing member 5 (6) is inserted into the coil springs 2, 3 (2, 4) from a direction (radial direction) perpendicular to the winding central axis direction 10, the coil spring is not compressed and the coil spring is not compressed. 2 and 3 (2, 4) can be fixed to each other, and the assembly work can be easily performed. Also, the large amount of equipment and jigs are not required for the assembly work as in the prior art. Can be reduced. Further, when the spring load has a multistage characteristic in the spring assembly, the inner coil spring 3 (4) can be fixed to the outer coil spring 2 by the fixing member 5 (6), and abnormal noise and unbalance can be reduced.

  A spring assembly according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 4 is a cross-sectional view schematically showing a configuration of a fixing member used in the spring assembly according to the second embodiment of the present invention.

  The second embodiment is a modification of the first embodiment, and a thin plate metal is used as the fixing member 7, and a gap between the windings of the coil spring (2, 3 (2, 4) in FIG. 1) (the fitting portion 2c, 3b (2d, 4b)). The fixing member 7 has, on the surface, outer concave portions 7a and 7b, inner concave portions 7c and 7d, convex portions 7e and 7f, and a tapered portion 7g similar to those of the fixing member of the first embodiment (5 and 6 in FIG. 2). However, since it is press-worked, it is different from the fixing member of Example 1 (5 in FIG. 2) in that it has a void in the member. Other configurations are the same as those in the first embodiment. According to the second embodiment, the same effects as the first embodiment can be obtained, and the cost can be reduced by pressing the fixing member 7.

  A spring assembly according to Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 5A is a plan view schematically showing the configuration of a fixing member used in the spring assembly according to the third embodiment of the present invention, and FIG. 5B is a cross-sectional view between XX ′. FIG. 6 is a partial cross-sectional view in the winding central axis direction schematically showing the configuration of the spring assembly according to the third embodiment of the present invention.

  The third embodiment is a modification of the first embodiment, in which cut portions 8a and 8b and a hook portion 8c are formed by pressing using a thin metal plate as the fixing member 8.

  The fixing member 8 is a member for fixing predetermined portions (the end portions 2a and 3a in FIG. 6) of the outer coil spring 2 and the inner coil spring 3 to each other. The fixing member 8 has a gap between the windings of both the outer coil spring 2 and the inner coil spring 3 when viewed from a direction perpendicular to the winding center axis direction 10 (radial direction). Are inserted into predetermined portions (the fitting portions 2c and 3b) disposed in the middle of the inner coil spring 3 that is continuous with the inner coil spring 3. The fixing member 8 is fitted in a portion where the gaps (fitting portions 2c and 3b) between the windings of both the outer coil spring 2 and the inner coil spring 3 are in contact with each other during compression. The fixing member 5 is formed in a semicircular shape, a fan shape, and a plate shape. The fixing member 8 is inserted and fitted into the fitting portions 2 c and 3 b of the outer coil spring 2 and the inner coil spring 3 from a direction (radial direction) perpendicular to the winding center axis direction 10. On the surface, the fixing member 8 has outer concave portions (5a and 5b in FIG. 2, inner concave portions (5c and 5d in FIG. 2), convex portions (such as the fixing members 5 and 6 in FIG. 2), and convex portions (see FIG. 2). 2e and 5f in FIG. 2 and the tapered portion (5g in FIG. 2) are not provided.

  The cut portions 8a and 8b are portions for allowing the fixing member 8 to be deformed in accordance with the shapes of the fitting portions 2c and 3b of the outer coil spring 2 and the inner coil spring 3.

  The hooking portion 8 c is provided to prevent the fixing member 8 from falling off when the fixing member 8 is fitted into the fitting portions 2 c and 3 b of the outer coil spring 2 and the inner coil spring 3. The hooking portion 8 c is cut into the main body of the fixing member 8 and rises from the main body of the fixing member 8 so that the tip of the hooking portion 8 c is hooked on the inner surface of the inner coil spring 3. When the fixing member 8 is assembled to the fitting portions 2c and 3b of the outer coil spring 2 and the inner coil spring 3, the hooking portion 8c has a small rise from the main body of the fixing member 8 when passing through the fitting portions 2c and 3b. It bends to become.

  Other configurations are the same as those in the first embodiment.

  According to the third embodiment, the same effects as the first embodiment can be obtained, and the cost can be reduced by pressing the fixing member 8.

  It should be noted that the embodiments and examples may be changed and adjusted within the scope of the entire disclosure (including claims and drawings) of the present invention and based on the basic technical concept. Various combinations or selections of various disclosed elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) are included within the scope of the claims of the present invention. Is possible. That is, the present invention naturally includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the drawings, and the technical idea.

DESCRIPTION OF SYMBOLS 1 Spring assembly 2 Outer coil spring 2a, 2b End part 2c, 2d Insertion part (predetermined part)
3, 4 Inner coil spring 3a, 4a End 3b, 4b Fitting part (predetermined part)
5, 6 Fixing member 5a, 5b Outer recess 5c, 5d Inner recess 5e, 5f Protrusion 5g, 6g Taper 7 Fixing member 7a, 7b Outer recess 7c, 7d Inner recess 7e, 7f Protrusion 7g Taper 8 Fixing member 8a , 8b Cut section 8c Hook section 10 Winding central axis direction

Claims (10)

An outer coil spring,
An inner coil spring disposed inside the outer coil spring;
A fixing member for fixing the outer coil spring and the inner coil spring at predetermined portions;
With
The fixing member has a gap between windings of the outer coil spring and the inner coil spring, as viewed from a direction perpendicular to the winding center axis direction of the outer coil spring and the inner coil spring, and A spring assembly, which is fitted into the predetermined portion arranged in the middle of the inner coil spring continuous in the winding central axis direction.   The spring according to claim 1, wherein the fixing member is fitted so that windings of both the outer coil spring and the inner coil spring are in contact with each other when the outer coil spring and the inner coil spring are compressed. Assembly.   3. The spring assembly according to claim 1, wherein the fixing member is sandwiched with a preload between one or both windings of the outer coil spring and the inner coil spring.   4. The spring set according to claim 1, wherein the fixing member has a recess corresponding to a shape of the predetermined portion of one or both of the outer coil spring and the inner coil spring. 5. Solid.   The fixing member has a protrusion protruding in one or both of the winding center axis directions at a portion between the outer coil spring and the inner coil spring in a direction perpendicular to the winding center axis direction. The spring assembly according to any one of claims 1 to 4.   The said fixing member has a taper part formed so that it might become thin as it goes to a front-end | tip part in the part extended inside the said inner coil spring, It is any one of Claim 1 thru | or 5 characterized by the above-mentioned. The spring assembly as described.   4. The fixing member according to claim 1, wherein the fixing member is formed using a thin metal plate and has a hooking portion configured to be hooked on an inner surface of the inner coil spring. 5. Spring assembly.   The spring assembly according to claim 7, wherein the hooking portion can be bent so as to pass through the predetermined portions of the outer coil spring and the inner coil spring.   9. The spring assembly according to claim 7, wherein the fixing member has a cut portion that can be deformed according to a shape of the predetermined portion of the outer coil spring and the inner coil spring.   In the free state of the outer coil spring and the inner coil spring, the predetermined portion is between windings in which a gap between lines first starts to open from the end portions of the outer coil spring and the inner coil spring. The spring assembly according to any one of claims 1 to 9.

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