WO2010038723A1

WO2010038723A1 - Compound spring

Info

Publication number: WO2010038723A1
Application number: PCT/JP2009/066912
Authority: WO
Inventors: 慶則本多
Original assignee: 株式会社東郷製作所
Priority date: 2008-10-01
Filing date: 2009-09-29
Publication date: 2010-04-08
Also published as: JP2010084912A

Abstract

A compound spring (S1) is provided with an outer spring (O1) and an inner spring (I1) inserted on the inner side of the outer spring (O1) so as to be substantially coaxial with the outer spring (O1), and the outer and inner springs are coiled compression springs. The inner spring (I1) and the outer spring (O1) are wound in the same direction. With regard to the springs (O1, I1), at all times, the positions of portions of the element wire of the inner spring (I1), said portions constituting at least the effective winding portion of the inner spring (I1) are axially located between the pitches of the element wire of the outer spring (O1), and the outer peripheral edges of the portions are radially located on the outer side of the inner peripheral edges of the element wire of the outer spring (O1).

Description

Combination spring

The present invention relates to a combination spring.

For example, a device that reciprocates at a high speed, such as an engine valve spring, 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 main coil spring is wound in the opposite direction 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, the part where both springs contact is limited to the intersecting part and is almost in a point contact state, so it can be said that there is still room for improvement in vibration damping.

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

The present invention is a combined spring comprising an outer spring formed by a compression coil spring, and at least one inner spring formed by the compression coil spring and inserted substantially coaxially inside the outer spring. When the effective winding portions of the inner spring and the outer spring are both set in the same winding direction and are in a natural state after the inner spring and the outer spring are combined, the effective winding in the inner spring In the axial direction of the combination spring, the positions of the strands of the portion are located with a pitch shift between the strands of the outer spring, and in the radial direction of the combination spring, the outer peripheral edge is the strand of the outer spring. It is the structure which protrudes and is located in the radial direction outer side rather than an inner periphery.

The following configuration is preferable as an embodiment of the present invention.
(1) An end spring is provided at at least one end of the outer spring and the inner spring in the axial direction, and the end spring on the inner spring side is press-fitted into the outer spring. The inner spring may be connected to the inner spring.

According to such a configuration, since both the outer and inner springs are assembled at the end winding portion, it is possible to avoid a situation where they are entangled during the expansion and contraction operation of the combination spring.

(2) An end spring is provided at at least one end of the outer spring and the inner spring in the axial direction, and an intermediate spring is press-fitted from the axial direction between the end winding of the inner spring and the outer spring. Accordingly, the outer spring and the inner spring may be connected to each other.

(3) At least one end side in the axial direction of the outer spring and the inner spring is assembled with a spring receiving member from the axial direction of the combined spring, and the spring receiving member is axially outer with respect to the end winding portion of the outer spring. A disc-shaped base plate portion that abuts from the inner surface of the base plate portion, a step portion concentrically protruding from the inner surface side of the base plate portion and press-fitted into the end winding portion of the outer spring, and a step portion that can be connected to the outer spring; It is good also as a structure formed from the axial part which can be connected with an inner spring by protruding concentrically and press-fitting in the axial direction edge part of an inner spring.

(4) In the process of compressing the outer spring and the inner spring, in the effective winding part of both springs, a pseudo close contact state in which a portion near the outer periphery of the inner spring strand is sandwiched between the outer spring strands. From this state, when further compression force is applied, at least the outer spring is deformed in the diameter increasing direction, or at least the inner spring is deformed in the diameter decreasing direction, so that the outer spring is in a pseudo-adhered state. It is good also as a structure which can be further compressed and deformed beyond this.

According to such a configuration, in the process of compressing the entire combination spring, the outer spring is expanded and deformed even after the inner spring strand is sandwiched between the outer spring strands and the outer spring is deformed. Since the inner spring deforms in a reduced diameter, this allows the combined spring to be compressed beyond the pseudo contact height.

(5) The inner spring has an axial length shorter than that of the outer spring, and is disposed at an intermediate portion in the axial direction with respect to the outer spring, and the end winding portions formed at both ends in the axial direction are outer springs. The inner spring and the outer spring may be connected to each other by being press-fitted into the inner part.

(6) The inner spring may be divided into two parts with respect to the axial direction.

(7) One of the two divided inner springs is formed only by the end winding portion that is press-fitted into the end winding portion formed on one end side of the outer spring, and the winding direction of the strand of the end winding portion May be configured to be opposite to the winding direction of the outer spring.

(8) The split surface of each of the two split inner springs may be formed on a plane substantially orthogonal to the axial direction of the combination spring and abut against each other.

According to 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 both the outer and inner springs are opposite to each other, the present invention has a greater damping performance than the contact portion is almost in a point-striking state. Obtainable. Further, in the case of a compression spring, it is well known that the maximum portion of stress is the inner peripheral portion of the strand, but in the case of the present invention, at least in the effective winding portion, the strand of the inner spring with respect to the axial direction is Since the opportunity of contact between the innermost peripheral edge of the outer spring element wire and the inner spring is reduced so as to be positioned between the outer spring lines, wear and the like are less likely to occur and the durability is excellent.

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

<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 arranged at 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 is composed of 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 slightly 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 rotating 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 O1, 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 and I1 form end winding parts SO1 and SI1, and both end windings SO1 and SI1 of both springs O1 and I1 are both spring seat 1 or It abuts on the cylinder head 3 side. 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, the inner spring I1 includes the natural state of the combination spring S1, and until the inner spring I1 reaches the close contact state (the state shown in FIG. 3) in the axial direction, the strand of the inner spring I1 (the end winding portion SI1) Are removed from each other so as to be positioned between the strands of the outer spring O1. 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.

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 strands of the inner spring I1 interfere with each other (the strands of the inner spring I1 in the radial direction are 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 reversed to each other, the vibration damping property is accordingly improved.

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. 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. 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. Along with this, the outer spring O1 is deformed to increase in diameter, while the inner spring I1 is deformed to reduce diameter, whereby the strands of the outer spring O1 can be brought into close contact with each other. Therefore, even when an abnormal operation occurs in the intake / exhaust valves, the expanded elastic deformation region can be retained.

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 one contact height in the combined state, it is not necessary to consider the contact height between the outer and inner combined states.

<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 barrel shape.

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 in 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 constituted 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. However, in the fifth embodiment, the second inner spring I5-B is formed only by the end wound portion. The winding direction is opposite to the outer spring O5 side. The upper end of the first inner spring I5-A is in contact with the lower end of the second inner spring I5-B.

Also in the fifth embodiment configured as described above, the same operational 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 the effective winding portion. However, in the present embodiment, the first and second inner springs I6-A are formed. , I6-B both have an effective winding portion and end winding portions SI6-A, SI6-B, and the lengths in the axial direction are substantially equal. The first and second inner springs I6-A and I6-B are both wound in the same winding direction as the outer spring O6. Also, the outer spring O6-A and the inner springs I6-A, I6-B all have different wire diameters, and the end surfaces of the inner springs I6-A, I6-B are in contact with 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, so that the same 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 (Md) slightly larger than the gap dimension (L1) between the outer peripheral surface of the restrictor winding portion SI7 ′ and the inner peripheral surface on the outer spring O7 side is provided. It is inserted with a press fit. 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 in the other embodiments, and the same operational effects can be exhibited.

<Embodiment 8>
FIG. 11 shows an eighth embodiment of the present invention. The combination spring S8 of the present embodiment is obtained by incorporating the spring receiving members 4 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 formed concentrically 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 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) The material of the inner spring and the outer spring may be the same or different.

(3) In the fourth embodiment shown in FIG. 7, both 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 disposed 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.

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

An outer spring formed by a compression coil spring;
A combination spring comprising at least one inner spring formed by a compression coil spring and inserted substantially coaxially into the outer spring;
The effective winding portions of the inner spring and the outer spring are both set in the same winding direction,
In addition, when the inner spring and the outer spring are in a natural state after being combined, the position of the strand of the effective winding portion in the inner spring is determined with respect to the axial direction of the combined spring. A combination spring that is positioned with a pitch deviation therebetween and that has an outer peripheral edge that protrudes radially outward from an inner peripheral edge of the outer spring with respect to the radial direction of the combination spring.
At least one end of the outer spring and the inner spring in the axial direction is provided with an end winding portion, and the end winding portion on the inner spring side is press-fitted into the outer spring to the end winding portion, The combination spring according to claim 1, wherein the outer spring and the inner spring are connected.
An end spring is provided at at least one end of the outer spring and the inner spring in the axial direction, and an intermediate spring is press-fitted in the axial direction between the end winding of the inner spring and the outer spring. The combined spring according to claim 1, wherein the outer spring and the inner spring are connected to each other.
On at least one end side in the axial direction of the outer spring and the inner spring, a spring receiving member is assembled from the axial direction of the combination spring, and
The spring receiving member includes a disc-shaped base plate portion that comes into contact with the end winding portion of the outer spring from the outside in the axial direction;
A stepped portion that can be connected to the outer spring by projecting concentrically from the inner surface side of the base plate portion and being press-fitted into the end winding portion of the outer spring,
The combined spring according to claim 1, wherein the stepped portion is formed from a shaft portion concentrically protruding from a shaft portion that can be connected to the inner spring by being press-fitted into an axial end portion of the inner spring.
In the process of compressing the outer spring and the inner spring, in the effective winding portion of the two springs, a pseudo close contact is made in such a manner that a portion near the outer periphery of the inner spring strand is sandwiched between the outer spring strands. From this state, when further compressive force is applied, at least the outer spring is deformed in the diameter increasing direction, or at least the inner spring is deformed in the diameter reducing direction, the outer spring is The combined spring according to claim 1, further capable of being compressed and deformed beyond the pseudo close contact state.
The inner spring has an axial length shorter than that of the outer spring, and is disposed at an intermediate portion in the axial direction with respect to the outer spring, and end winding portions formed at both ends in the axial direction have the outer spring. The combination spring according to claim 1 or 5, wherein the inner spring and the outer spring are connectable by being press-fitted into the spring.
The combined spring according to claim 5, wherein the inner spring is divided into two parts in the axial direction.
The combined spring according to claim 7, wherein the split surfaces of the inner spring divided into two are formed in a plane substantially perpendicular to the axial direction of the combined spring and are in contact with each other.
An outer spring formed by a compression coil spring;
A combination spring comprising at least one inner spring formed by a compression coil spring and inserted substantially coaxially into the outer spring;
The effective winding portions of the inner spring and the outer spring are both set in the same winding direction,
In addition, when the inner spring and the outer spring are in a natural state after being combined, the position of the strand of the effective winding portion in the inner spring is determined with respect to the axial direction of the combined spring. The outer peripheral edge of the combined spring is positioned so as to protrude radially outward from the inner peripheral edge of the outer spring with respect to the radial direction of the combination spring.
The inner spring is a combination spring that is divided into two in the axial direction.
One of the two divided inner springs is formed only by the end winding portion that is press-fitted into the end winding portion formed on one end side of the outer spring, and the winding direction of the strand of the end winding portion is The combined spring according to claim 7, wherein the combined spring is in a direction opposite to a winding direction of the outer spring.