JP2010084912A - Combination spring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combination spring improving a vibration damping function. <P>SOLUTION: The combination spring S1 includes an outer spring O1 and an inner spring I1 inserted through the inside of the outer spring O1 almost coaxially, and the respective springs are formed of compression coil springs. The inner spring I1 and the outer spring O1 are formed in the same winding direction, and both spring O1, I1 are formed such that, as to an axial direction, the position of an element wire in at least an effective wound part in the inner spring I1 is located between the element wire pitches of the outer spring O1 and that, as to a radial direction, the outer peripheral edge is located radially outside of the element wire inner peripheral edge of the outer spring O1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a combination spring.

For example, a device that reciprocates at a high speed, such as a valve spring of an engine, requires a device for preventing surging. As an example, Patent Document 1 below is known. This has a double spring structure in which a vibration damping coil spring is coaxially fitted inside the main coil spring.
Japanese Utility Model Publication No. 60-52435

  In the conventional coil spring described above, the winding direction of the main coil spring is reversed in the vibration damping coil spring fitted inside. Therefore, the main coil spring and the damped vibration coil spring come into contact with each other at a portion where the strands intersect each other. This can suppress the resonance of the coil spring.

  However, it can be said that there is still room for improvement in the vibration damping property because the part where the two springs are in contact is limited to the intersecting part and is almost in a point contact state.

  The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a combination spring having an excellent vibration damping function.

  As means for achieving the above object, the invention of claim 1 is characterized in that an outer spring and at least one inner spring inserted substantially coaxially inside the outer spring are formed by compression coil springs. The inner spring and the outer spring are formed in the same winding direction, and both the springs are always arranged such that the position of the strand at least at the effective winding portion of the inner spring is a shaft. With respect to the direction, the outer spring is located between the strand pitches, and with respect to the radial direction, the outer peripheral edge thereof is located radially outside the outer peripheral strand of the outer spring. Have

  However, the inner spring of the present invention is a concept including a configuration in which the inner spring is divided into a plurality of parts.

  According to a second aspect of the present invention, in the one according to the first aspect, at least one end portion in the axial direction of the outer and inner springs is provided with a counterwinding portion, and the two springs are connected to each other. It has a feature where it is assembled.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the outer and inner springs each include a dummy in which a strand of the inner spring is sandwiched between the strands of the outer spring. When the compression force is further applied from the close contact state, the outer spring and / or the inner spring is deformed in the direction of diameter expansion and / or contraction, so that the outer spring is further compressed beyond the pseudo contact state. It is characterized in that it can be deformed.

<Invention of Claim 1>
According to the first aspect of the present invention, since the inner spring and the outer spring are in the same winding direction, both the outer and inner springs come into contact with each other when the entire combination spring expands and contracts. On the other hand, when the winding directions of the outer and inner springs are opposite to each other, the contact portion is almost in a point-striking state, so that the invention of claim 1 is larger. Attenuation can be obtained. In the case of a compression spring, it is well known that the maximum stress portion is the inner peripheral portion of the strand. However, in the case of claim 1, at least in the effective winding portion, the strand of the inner spring is in the axial direction. Since the contact between the innermost peripheral edge of the outer spring wire and the inner spring is reduced so as to be positioned between the outer spring lines, wear or the like hardly occurs and the durability is excellent.

<Invention of Claim 2>
According to the second aspect of the present invention, since both the outer and inner springs are assembled in the end winding portion, it is possible to avoid a situation in which they are entangled during the expansion and contraction operation of the combination spring.

<Invention of Claim 3>
According to the third aspect of the present invention, the outer spring and / or the inner spring is in the process of compressing the whole combination spring even after the inner spring strand is sandwiched between the outer spring strands and the pseudo spring is brought into contact. The outer spring can be compressed beyond the pseudo-adhesion height by expanding and / or reducing the diameter.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS. The combination spring S1 in the first embodiment is used as a valve spring for an intake valve or an exhaust valve of an engine. As shown in FIG. 1, the combination spring S1 is inserted through valve stems (not shown) of both valves, and one end side (the upper end side in the drawing) is brought into contact with the spring seat 1 disposed on the upper end portion of the valve stem, The other end (the lower end in the figure) is in contact with a wall surface around the stem through hole 2 formed in the cylinder head 3. In a state in which the combination spring S1 is assembled in the cylinder head 3, the compressed state is compressed by a predetermined length from the natural state (the state shown in FIG. 2).

  The combination spring S1 includes an outer outer spring O1 and an inner spring I1 that is coaxially incorporated inside the outer spring O1. Both springs O1 and I1 are compression coil springs formed by spirally winding an element wire made of spring steel into a cylindrical shape. More specifically, the outer spring O1 is formed in a cylindrical shape having a uniform outer diameter over the entire length, and the inner spring I1 is formed in a substantially barrel shape whose diameter is reduced only at both ends.

  The inner spring I1 is wound in the same direction as the winding direction of the outer spring O1, and when incorporated into the outer spring O1, the inner spring I1 is incorporated while being rotated around the axis. The strands of both the outer and inner springs O1, I1 are both substantially circular in cross section (otherwise, they may be in the form of an ellipse in the radial direction of the entire spring, or in the shape of a generally oval pointed on the outer peripheral side or inner peripheral side) And the inner wire diameter of the inner spring I1 is smaller than that of the outer spring, that is, the inner spring I1 side has a smaller diameter.

  At both ends of the combined spring S1, both the outer and inner springs O1, I1 form end turns SO1, SI1. The outer diameter of the both-ends winding part SI1 of the inner spring I1 is set slightly larger than the inner diameter of the both-ends winding part SO1 of the outer spring O1, so that this dimensional difference is the outer and inner springs O1, I1. The outer and inner springs O1, I1 are fastened to each other at the end winding portions SO1, SI1. Thereby, the situation where both springs O1 and I1 are entangled can be avoided as much as possible.

  Further, until the inner spring I1 reaches the close contact state in the axial direction (the state shown in FIG. 3), the strands of the inner spring I1 (except for the end wound portion SI1) are positioned between the strands of the outer spring O1. I have to do it. As for the radial direction, the outer peripheral edge (the outermost edge in the radial direction) of the strand of the inner spring I1 is always the inner peripheral edge (in the radial direction) of the outer spring O1. It is positioned slightly outward in the radial direction from the innermost edge). With such a positional relationship, the strand of the inner spring I1 comes into contact with the strand of the outer spring O1 in a line-contact state with contraction deformation of the outer spring O1.

  According to the first embodiment configured as described above, the inner spring I1 performs a combination operation on the outer spring O1 from one end side thereof. Then, both the outer and inner springs O1 and I1 are integrated by being tightened together at the both end wound portions SI1 of the inner spring I1 and the both end wound portions SO1 of the outer spring O1.

  In the attached state of FIG. 1, when the reciprocating motion of the combination spring S1 is repeated, the positional relationship in which the strands of the outer spring O1 and the inner spring I1 interfere with each other (the strands of the inner spring I1 are in relation to the radial direction). Therefore, the resonance phenomenon is mitigated by a damper effect caused by the contact between the inner spring I1 side strand and the outer spring O1 side strand sandwiching the outer spring O1 strand. be able to. Specifically, when the outer spring O1 vibrates, the inner spring I1 does not follow this, so each strand of the inner spring I1 collides with a strand of the outer spring O1 that sandwiches the inner spring I1, and the resonance is reduced. Is planned. In particular, in the present embodiment, the inner spring I1 and the outer spring O1 are in the same winding direction. Therefore, when the springs O1, I1 are compressed, the outer and inner springs O1, I1 are along the winding direction. “Line per line”. Therefore, since the length region in contact with each other is longer than that in the conventional case where the winding directions are opposite to each other and set in the “point hitting state”, the vibration damping performance is excellent accordingly.

  Further, in the effective winding portion, the strand of the inner spring I1 is positioned between the strands of the outer spring O1 in the axial direction, and in the compression region that is normally used, the strand of the inner spring I1 is the strand of the outer spring O1. Do not touch the innermost periphery of the line. Therefore, wear due to contact does not occur. As described above, when the compressive force is applied to the outer spring O1, the portion where the stress is maximized is the inner peripheral edge portion. Therefore, in order to improve the durability, no wear is caused here. It is extremely effective.

  FIG. 3 shows a state where the strands of the outer spring O1 are in close contact with each other and the combined spring S1 has a true contact height that cannot be compressed any more. In the case of the present embodiment, a pseudo contact state (see FIG. 4) is passed before reaching such a true contact height. This pseudo close contact state refers to a state in which the strand of the inner spring I1 is sandwiched between the strands of the outer spring O1, and at this time, between the strands of the outer spring O1, the outer diameter of the strand of the inner spring I1 extends in the axial direction. Small dimension clearance is retained. When a compressive force is further applied from this pseudo close contact state, both strands of the outer spring O1 sandwiching each strand of the inner spring I1 act so as to push the strand of the inner spring I1 radially inward. Accordingly, the outer spring O1 and / or the inner spring I1 is expanded and / or contracted in diameter, so that the strands of the outer spring O1 can be brought into close contact with each other. Therefore, it is possible to have an elastic deformation region when an abnormal operation occurs in the intake / exhaust valves.

  In general, when the double spring structure is adopted, both the outer and inner springs O1 and I1 need to have the same contact height in the single product state. Since the outer and inner springs O1 and I1 are assembled in SO1 and SI1 to obtain a single contact height in the combined state, there is no need to consider the close contact height in the combined state of the outer and inner.

<Embodiment 2>
Next, Embodiment 2 of the present invention will be described with reference to FIG. In the combination spring S2 of the second embodiment, the inner spring I2 is formed in a cylindrical shape having a uniform outer diameter over the entire length range, and the outer spring O2 is formed in a substantially drum shape in which only both end portions in the axial direction are expanded. Forming. Accordingly, in the present embodiment, the end springs SO2 and SI2 have a structure in which the springs O2 and I2 are not tightened together.

  Other configurations are the same as those of the first embodiment, and the same operational effects can be exhibited.

<Embodiment 3>
FIG. 6 shows Embodiment 3 of the present invention. In the combination spring S3 of the present embodiment, the length of the inner spring I3 in the axial direction is shorter than that of the outer spring O3, and is combined with the outer spring O3 at an intermediate portion in the axial direction. The outer spring O3 is formed in a cylindrical shape having a uniform outer diameter over the entire length range, and end winding portions SO3 are formed at both ends in the axial direction. On the other hand, the inner spring I3 also has end winding portions SI3 at both ends in the axial direction, and the range excluding the end winding portion SI3 has a larger outer diameter than that of the end winding portion SI3 in the axial direction. The whole is formed in a substantially drum shape.

  Both the outer and inner springs O3 and I3 are tightened with respect to the outer spring O3 at both end wound portions SI3 of the inner spring I3.

  Other configurations are the same as those of the first and second embodiments, and the same operational effects can be exhibited.

<Embodiment 4>
FIG. 7 shows Embodiment 4 of the present invention. In the combination spring S4 of the present embodiment, the outer spring O4 is formed in a cylindrical shape having a uniform outer diameter over the entire length range, and the inner spring I4 is formed by strands of the same number of turns at both ends in the axial direction. Is formed in close contact part SI4. The end face in the axial direction of the end turn SI4 on the inner spring I4 side is in a position retracted inward in the axial direction from the end face of the end turn SO4 on the outer spring O4 side. Both end wound portions SI4 of the inner spring I4 are formed to have a smaller diameter than the effective winding portion, and are combined with a predetermined tightening margin on the outer spring O4 side.

  Other configurations are the same as those of the other embodiments, and the same operational effects can be exhibited.

<Embodiment 5>
FIG. 8 shows Embodiment 5 of the present invention. The combination spring S5 of the present embodiment has a form similar to that of the fourth embodiment described above. The difference is that in the fifth embodiment, the inner spring I5 is divided into first and second inner springs I5-A and I5-B, and is configured by three members as a whole. In the fourth embodiment, both the end wound portions SI4 of the inner spring I4 are tightly wound in the same winding direction as the outer spring O4 side, but in the fifth embodiment, the second inner spring I5-B is formed only by the end wound portion. The winding direction is formed and is opposite to the outer spring O5 side.

  In the fifth embodiment configured as described above, the same effects as those of the other embodiments can be exhibited. The second inner spring I5-B may have the same setting as the wire diameter of the first inner spring I5-A or a different setting.

<Embodiment 6>
FIG. 9 shows Embodiment 6 of the present invention. Similarly to the fifth embodiment described above, the combination spring S6 of the present embodiment also has a configuration in which the inner spring I6 is divided into first and second inner springs I6-A and I6-B. However, in the fifth embodiment, the second inner spring I5-B is formed only by the end winding portion and does not have an effective winding portion, but in the present embodiment, the first and second inner springs I6-A. , I6-B have effective winding portions and end winding portions SI6-A, SI6-B, and the axial lengths are substantially equal. Further, both the first and second inner springs I6-A and I6-B have the same winding direction as the outer spring O6. Further, the outer spring O6-A and the inner springs I6-A, I6-B all have different wire diameters. Further, the end surfaces of the inner springs I6-A, I6-B are abutted against each other. Are formed with mutually flat ground surfaces so that they are abutted while forming a plane substantially perpendicular to the axis.

  Other configurations are the same as those of the fifth embodiment, and thus the same operational effects as those of the other embodiments can be exhibited.

<Embodiment 7>
FIG. 10 shows Embodiment 7 of the present invention. The combination spring S7 of the present embodiment has an intermediate spring M interposed between the inner spring I7 and the outer spring O7 on one end side (the lower end side in the drawing) of the inner spring I7. The outer spring O7 in this embodiment is formed in a cylindrical shape having the same diameter over the entire length. A small-diameter end wound portion SI7 is formed on the other end side (the upper end side in the drawing) of the inner spring I7, and is fastened to the end turn portion SO7 of the outer spring O7. One end side of the inner spring I7 is formed with a throttle end wound part SI7 'formed to have a smaller diameter than the outer diameter of the end wound part SI7 on the other end side. An intermediate spring M having an element wire diameter slightly larger than the gap dimension between the outer peripheral surface of the restrictor winding portion SI7 ′ and the inner peripheral surface on the outer spring O7 side is interposed in a press-fit manner. ing. Tightening margins are set for the narrow end winding part SI7 'with respect to the end winding part SO7 on one end side of the inner spring I7 and one end side of the outer spring O7.

  Other configurations are the same as those of the other embodiments, and the same operational effects can be exhibited.

<Eighth embodiment>
FIG. 11 shows Embodiment 8 of the present invention. The combination spring S8 of this embodiment is one in which the spring receiving members 4 are incorporated at both ends of the inner spring I8. Both spring receiving members 4 are made of metal and have a base plate portion 4A that abuts against the end surfaces of both end wound portions SO8 of the outer spring O8. The base plate portion 4A is formed to have substantially the same diameter as the outer diameter of the end winding portion SO8 of the outer spring O8. A concentric disc-shaped step 4B is formed on the inner surface side of the base plate 4A so as to protrude. The outer diameter of the stepped portion 4B is formed to be larger than the inner diameter of the end winding portion SO8 of the outer spring O8, which serves as a tightening allowance for the outer spring O8. A shaft portion 4C is concentrically formed on the inner surface side of the step portion 4B. Both ends of the inner spring I8 have a reduced diameter, and the entire inner spring I8 is formed in a barrel shape. The shaft portion 4C is press-fitted into both end portions of the inner spring I8. That is, the outer diameter of the shaft portion 4C is formed to be slightly larger than the inner diameters of both end portions of the inner spring I8, and this is an allowance for the inner spring I8.

  Other configurations are the same as those of the other embodiments, and the same operational effects can be exhibited.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.

  (1) In any of the embodiments, the wire diameter of the inner spring is smaller than the wire diameter on the outer spring side, but it may be set to the same diameter or vice versa.

  (2) Further, the inner spring and the outer spring may be made of the same material or different materials.

  (3) In the fourth embodiment shown in FIG. 7, both the end wound portions SI4 of the inner spring I4 are formed by close winding, but may be formed by close winding only on one side. Further, in place of the tight winding, the end winding portions may be formed at an unequal pitch as a pitch that is narrower than the effective winding portion but does not reach the tight winding. In that case, it is also possible to adopt a form in which the end winding portion is arranged only on one side.

  (4) In the seventh embodiment shown in FIG. 10, the intermediate spring M is interposed only at one end, but it may be arranged at both ends.

  (5) In the eighth embodiment shown in FIG. 11, the spring receiving member is made of metal, but may be made of synthetic resin. However, it is only necessary to receive the spring, and the material is not particularly limited.

Sectional drawing in the state which assembled | attached the combination spring in Embodiment 1 as a valve spring Cross section in the free state Sectional view in a compressed state up to the contact height Sectional view in pseudo contact state Sectional drawing in the free state in Embodiment 2 Sectional drawing in the free state in Embodiment 3 Sectional drawing in the free state in Embodiment 4 Sectional drawing in the free state in Embodiment 5 Sectional drawing in the free state in Embodiment 6 Sectional drawing in the free state in Embodiment 7 Sectional drawing in the free state in Embodiment 8

Explanation of symbols

S1 to S8 ... combination springs O1 to O8 ... outer springs I1 to I8 ... inner springs SO1 to SO8 ... end winding parts SI1 to SI8 ... end winding parts

Claims (3)

A combination spring comprising an outer spring and at least one inner spring inserted substantially coaxially into the outer spring, each formed by a compression coil spring;
The inner spring and the outer spring are formed in the same winding direction, and the two springs always have the position of the wire in at least the effective winding portion of the inner spring, and the axial direction of the outer spring. A combination spring characterized in that the outer circumferential edge is located between the strand pitches and the outer circumferential edge is located radially outside the inner circumferential edge of the outer spring. The combined spring according to claim 1, wherein an end winding portion is provided at at least one end portion in the axial direction of both the outer and inner springs, and both springs are assembled to each other at the end winding portion. . The outer spring and / or the inner spring are configured so that the outer spring and / or the outer spring and / or the outer spring and / or the outer spring and / or the inner spring and / or the inner spring and / or the inner spring are The inner spring is deformed in the direction of expansion and / or contraction, so that the outer spring can be further compressed and deformed beyond the pseudo contact state. Combination spring.

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