JP6637093B2 - Coil spring - Google Patents

Description

  The present invention relates to a coil spring that can be used as a valve spring of an internal combustion engine, a spring for a high-pressure pump, and the like.

  Coil springs formed by forming a spring wire into a spiral shape extending from one side to the other side in the axial direction are widely used as valve springs for internal combustion engines, springs for high-pressure pumps, and the like.

  The coil spring is a member intended to exhibit an elastic force along the axial direction when compressed in the axial direction, but when compressed, in addition to the elastic force along the axial direction, It is known that a force (lateral force) is also generated in a direction orthogonal to the direction.

It is desirable to prevent the generation of lateral force as much as possible.
That is, for example, when a lateral force is generated when the coil spring is used as a pressing member of a reciprocating plunger, friction generated between the plunger and a guide surface in which the plunger is reciprocally accommodated. Strength increases.
The increase in the frictional force causes wear and an increase in frictional heat due to the sliding resistance of the plunger, which may cause malfunction of a device such as a high-pressure pump using the plunger.

  In this regard, the first applicant of the present application has proposed a coil spring for reducing lateral force (see Patent Document 1 below).

  The coil spring described in Patent Document 1 is designed such that the effective number of turns is an integer between the set height and the maximum use height, and the effective number of turns is not an integer or near an integer. Lateral force can be reduced as compared with a coil spring.

  By the way, the coil spring has an end winding portion located at both ends in the axial direction and a center winding portion located between the end winding portions at both ends, and is provided between spring wires adjacent in the axial direction. An area where a gap (interline gap) exists is an effective winding portion.

  Patent Document 1 discloses the idea of designing the number of turns of the effective winding portion to be an integer between the set height and the maximum use height.

JP-A-2000-205320

  An object of the present invention is to provide a coil spring capable of preventing generation of lateral force as much as possible.

  In order to achieve the above object, the present invention provides a first end turn portion provided on one side in the axial direction and having a first seating surface facing one side in the axial direction, and a first end turn portion provided on the other side in the axial direction. A coil spring comprising: a second end turn having a second seat surface facing the other side in the direction; and a center turn between the first and second end turns. A first end turn edge region extending from a first end portion on one side in the axial direction to a portion forming a first reference point where a line gap in a natural length state is zero on one side in the axial direction; A first end turn transition region extending from the first end turn edge region to the central turn, wherein the first end turn edge region, compared to the first end turn transition region, The coil spring is bent to one side in the axial direction, and the first seat surface is the first end winding. Providing parts edge regions and a coil spring which is formed straddling said first seat winding portion transition region.

  Preferably, the second end turn portion extends from the second end portion on the other side in the axial direction to a portion forming a second reference point where the line gap in the natural length state is zero on the other side in the axial direction. It includes a second end turn edge region and a second end turn transition region extending from the second end turn edge region to the central turn, wherein the second end turn edge region includes the second end turn edge region. The coil spring is bent to the other side in the axial direction as compared with the 2 end winding portion transition region, and the second seat surface is formed in the second end winding portion edge region and the second end winding portion transition region. It is formed straddling.

  In the coil spring according to the present invention, a first end turn portion provided on one side in the axial direction and having a first seating surface facing one side in the axial direction is provided, and a first end turn portion provided on the other side in the axial direction and the other side in the axial direction. A second end winding portion formed with a second seat surface facing the first end winding portion, and a center winding portion between the first and second end winding portions. A first end turn edge region extending from one end to a portion forming a first reference point where a line gap in a natural length state is zero on one side in the axial direction is formed from the first end turn edge region. The coil spring is bent toward one side in the axial direction of the coil spring as compared with the first end turn transition region extending to the central turn, and the first seat surface is formed by the first end turn edge region and the first end turn. Since it is formed so as to straddle the end turn transition region, the first seat surface is ground. While the amount to ensure sufficient to ensure the flatness of the first seating surface, wherein it is possible to thicken the first seat winding portion, it is possible to reduce the lateral forces generated during the compression operation.

FIG. 1 is a perspective view of a coil spring according to an embodiment of the present invention in a natural length state. FIG. 2 is a front view of the coil spring in a natural length state. FIG. 3 is a graph showing the relationship between the number of turns between wires and the gap between wires in the coil spring. FIG. 4 is a front view of the coil spring in a compressed state. FIG. 5 is a schematic view of an apparatus for manufacturing the coil spring. FIG. 6 is a graph showing the results of the experiment. FIG. 7 is a partial front view of a coil spring according to a modification of the embodiment.

Hereinafter, an embodiment of a coil spring according to the present invention will be described with reference to the accompanying drawings.
1 and 2 show a perspective view and a front view, respectively, of the coil spring 1A according to the present embodiment in a natural length state.

  As shown in FIGS. 1 and 2, a coil spring 1 </ b> A according to the present embodiment is configured such that a spring wire 100 is formed in a spiral shape extending from one side in the axial direction to the other side. And springs for high pressure pumps.

  The coil spring 1A includes a first end 110 on one side in the longitudinal direction of the spring wire 100, based on the actual winding of the spring wire 100, and a first end 110 that faces one side in the axial direction of the coil spring 1A. A second seat including a first end winding portion 10 on which one seat surface 11 is formed, and a second end portion 120 on the other side in the longitudinal direction of the spring wire 100, and facing the other side in the axial direction of the coil spring 1A. It has a second end turn 20 having a surface 21 formed thereon, and a center turn 30 between the first and second end turns 10 and 20.

  In the coil spring 1A, a region in which an interline gap exists between the spring wires 100 adjacent to each other in the axial direction of the coil spring 1A acts as an effective winding portion exhibiting an elastic force.

Here, the interline gap between the spring wires 100 adjacent in the axial direction will be described in detail.
The line gap expands in the axial direction from the first reference point 51 where the line gap in the natural length state is zero on one side in the axial direction to the one side in the axial direction spirally. A reference value L (L> 0, see FIG. 3 below) is set in accordance with the elastic force required for the coil spring 1A. The reference value L decreases on the other side in the axial direction as it spirals toward one side in the axial direction. It is set to zero at the two reference points 52.

  That is, as shown in FIG. 2, the spiral shape formed by the gap between the lines (hereinafter referred to as the winding between the lines) is such that the gap between the lines in the natural length state on one side in the axial direction is zero. A first end region 61 in which the gap between the lines in the natural length state increases as the circumferential direction progresses along the spiral shape from one reference point 51 to the other side in the axial direction, and an axial direction more than the first end region 61 A reference region 65 located on the other side and having a gap between lines in a natural length state having a reference value of L, and located on the other side in the axial direction from the reference region 65, along the spiral shape toward the other side in the axial direction. There is a second end region 62 in which the line gap becomes narrower as it advances in the circumferential direction, and the line gap in the natural length state becomes zero at the second reference point 52.

  FIG. 3 is a graph showing the relationship between the number of turns between wires and the gap between wires in the coil spring 1A.

  As shown in FIG. 3, in the coil spring 1 </ b> A according to the present embodiment, the first end region 61 has a line-to-line distance in a natural length state at the end position 61 </ b> E in which the number of line turns exceeds one. Is larger than the reference value L.

  In the present embodiment, as shown in FIG. 3, the end position 61E of the first end region 61 is located at a position of about 1.2 turns between the first reference point 51 and the other side in the axial direction from the first reference point 51. The reference value L is set to 4.7 mm, and the distance between the lines in the natural length state at the end position 61E is set to 5.5 mm (reference value L × 1.17).

  Then, as shown in FIG. 3, the coil spring 1 </ b> A is configured such that the line winding has a first transition region 63 (1) between the first end region 61 and the reference region 65. Have been.

  The first transition area 63 (1) is such that the distance between the lines decreases as the helical shape progresses from the end position 61 </ b> E of the first end area 61 to the other side in the axial direction and reaches the reference value L. Is configured.

  With this configuration, when the coil spring 1 </ b> A performs the compression operation from the natural length state, it is possible to effectively prevent the occurrence of zero line gap in the first end region 61, and the lateral force during the compression operation is reduced. Can be effectively suppressed.

That is, in the coil spring 1A, the line distance at the end position 61E of the first end region 61 provided on one side in the axial direction is larger than the reference value L.
Therefore, in the compression operation of the coil spring 1A as shown in FIG. 4, it is possible to effectively prevent a change in the effective number of turns on one side in the axial direction, thereby reducing the generation of a lateral force during the compression operation. It can be effectively suppressed.

  As shown in FIG. 3, in the coil spring 1 </ b> A according to the present embodiment, the second end region 62 has a line-to-line distance of more than 1 and a line length in a natural length state at the end position 61 </ b> E. Is larger than the reference value L.

In the present embodiment, the second end region 62 has substantially the same configuration as the first end region 61.
That is, as shown in FIG. 3, the start position 62S of the second end region 62 is located at a position of about 1.2 turns in the axial direction from the second reference point 52 to one side in the axial direction with respect to the number of turns between the lines. The line distance in the natural length state at the start position 62S is set to 5.5 mm (reference value L × 1.17), which is the same as the line distance at the end position 61E in the first end region 61.

  Then, as shown in FIG. 3, the coil spring 1 </ b> A is configured such that the wire winding has a second transition area 63 (2) between the reference area 65 and the second end area 62. Have been.

  In the second transition region 63 (2), as the distance from the terminal position 65E of the reference region 65 to the other side in the axial direction along the spiral shape increases, the distance between the lines increases from the reference value L, and the second end region It is configured to reach a start position 62S of 62.

  With such a configuration, when the coil spring 1A performs the compression operation from the natural length state, it is possible to effectively prevent the occurrence of zero line gap in the second end region 62, and the lateral force during the compression operation Can be effectively suppressed.

The coil spring 1A is manufactured by, for example, a manufacturing apparatus 200 shown in FIG.
As shown in FIG. 5, the manufacturing device 200 is guided by the supply roller 210 that supplies the spring wire 100, a guide member 215 that guides the spring wire 100 conveyed by the supply roller 210, and guided by the guide member 215. First and second coiling tools 220 (1) that are provided on the downstream side in the transport direction of the spring wire 100 transported by the supply roller 210 in the folded state, and form the linear spring wire 100 into a helical coil spring 1A. , 220 (2), a metal core member 225 for guiding the coil spring 1A spirally formed by the first and second coiling tools 220 (1), 220 (2), and a pitch of the coil spring 1A. And a cutting tool 235 for cutting the spring wire 100 in cooperation with the core metal 225. There.

  The positions of the first and second coiling tools 220 (1) and 220 (2) can be adjusted in the radial direction with reference to the center of the coil spring 1A to be formed. Change the coil diameter of the coil spring 1A.

  The pitch tool 230 can adjust the position in the radial direction with reference to the center of the coil spring 1A, and changes the pitch of the coil spring 1A according to the change in the radial position.

  The cutting tool 235 is reciprocally movable in the radial direction with reference to the center of the coil spring 1 </ b> A, and cooperates with the engaging surface 226 of the cored bar 225 to cut the spring wire 100. It is movable between a retracted position separated from the cored bar 225.

Preferably, as shown in FIG. 3, the first end region 61 has a constant line gap pitch angle from the first reference point 51 to the terminal position 61E, and the line gap pitch angle Is set such that the amount of displacement between the wire gaps per one turn between the wires in the axial direction is L.
According to such a configuration, the position control of the pitch tool 230 can be facilitated.

  Similarly, preferably, as shown in FIG. 3, the second end region 62 has a constant line gap pitch angle from a start position 62S to the second reference point 52, and the line gap The pitch angle is set such that the amount of displacement between the wire gaps per one turn between the wires in the axial direction is -L.

  Here, a description will be given of the results of experiments on the lateral force performed on the coil spring 1A according to the present embodiment and the conventional coil spring.

As an example (example) of the coil spring 1A according to the present embodiment, a coil spring 1a having the following configuration was prepared.
-Configuration of the coil spring 1a according to the embodiment Material of the spring wire: Silicon chrome steel Oil-tempered wire (SWOSC-V) or equivalent steel wire Wire diameter of the spring wire: 3.3 mm
Coil diameter of coil spring: 17.4 mm
Length of coil spring in natural length state: 41 mm
Total number of turns: 6.0
Effective number of turns: 4.0
Distance between line gaps in reference region 65 (reference value L): 4.6 mm
End position 61E of first end region 61 (number of turns between lines from first reference point 51): 0.9
Distance between the line gaps at the end position 61E of the first end region 61: 5.7 mm
Number of turns between lines in the first transition area 63 (1): 0.5
Start position 62S of second end region 62 (number of turns between lines from second reference point 52): 0.9
Distance between the line gaps at the start position 62S of the second end region 62: 5.7 mm
Number of turns between lines of the second transition area 63 (2): 0.5

The lateral force generated in the coil spring 1a according to the example was measured with a side force spring tester (SFT series manufactured by Japan Measurement System Co., Ltd.).
FIG. 6 shows the results.

As an example (comparative example) of a conventional coil spring, a coil spring having the following configuration was prepared, and a similar experiment was performed.
-Configuration of coil spring according to comparative example Material of spring wire: Silicon chrome steel Oil-tempered wire (SWOSC-V) or equivalent steel wire Spring wire diameter: 3.3 mm
Coil diameter of coil spring: 17.4 mm
Length of coil spring in natural length state: 40mm
Total number of turns: 5.8
Effective number of turns: 3.8
Distance between line gaps in reference region 65 (reference value L): 6.1 mm
End position 61E of first end region 61 (number of turns between lines from first reference point 51): 1
Distance between the line gaps at the end position 61E of the first end region 61: 6.1 mm
Start position 62S of second end region 62 (number of turns between lines from second reference point 52): 1
Distance between line gaps at the start position 62S of the second end region 62: 6.1 mm

The lateral force generated in the comparative example was also measured by the side force spring tester (SFT series manufactured by Nippon Keisoku System).
The results are also shown in FIG.

As shown in FIG. 6, the number of turns between the first and second end regions 61 and 62 exceeds 1, and the end position 61E of the first end region 61 and the second end region 62 In the embodiment 1a in which the line distance at the start position 62S is larger than the line distance L in the reference region 65, the generation of the lateral force is remarkably suppressed as compared with the comparative example. I have.
This result means that in the coil spring 1a according to the embodiment, a zero gap between lines can be effectively prevented in the first and second end regions 61 and 62 during the compression operation.

Preferably, the coil spring 1A is configured such that the number of turns between the lines from the first reference point 51 to the second reference point 52 is an integral multiple.
That is, the first reference point 51 and the second reference point 52 are configured to be located at the same position in the circumferential direction.
According to this configuration, it is possible to more effectively prevent the generation of the lateral force during the compression operation.

  Also, preferably, a region of the first end winding portion 10 located on the end side from the first reference point 51 can be bent to one side in the axial direction.

  FIG. 7 is a partial front view of a modified example 1B in which a region of the first end winding portion 10 located on the end side from the first reference point 51 is bent to one side in the axial direction.

  As shown in FIG. 7, in Modification 1B, the first end turn 10 is a portion of the spring wire 100 that forms the first reference point 51 from the first end 110 on one side in the longitudinal direction. A first end turn edge region 111 extending to the first end turn edge region 111 and a first end turn transition region 112 extending from the first end turn edge region 111 to the central turn 30.

  The first end turn edge region 111 is bent to one side in the axial direction of the coil spring 1B compared to the first end turn transition region 112, and the first seat surface 11 is It is formed so as to extend from the first end turn edge region 111 to the first end turn transition region 112 across the boundary between the first end turn transition region 112.

  According to the modified example 1B of such a configuration, the first seat winding portion 10 is thickened while securing the polishing amount of the first seating surface 11 sufficiently and ensuring the flatness of the first seating surface 11. Therefore, the generation of the lateral force during the compression operation can be further reduced.

Naturally, the same configuration can be applied to the second end winding portion 20.
That is, the second end turn portion 20 extends from the second end 120 on the other side in the longitudinal direction of the spring wire 100 to a portion forming the second reference point 52 (shown in the figure). And a second end turn transition region (not shown) extending from the second end turn edge region to the central turn 30. The second end turn edge region is defined by the second end turn edge region. The coil spring 1 is bent to the other side in the axial direction as compared with the end turn transition region, and the second seat surface 21 is moved from the second end turn edge region to the second end turn transition region. Can be formed so as to reach the second end winding transition region.

1A, 1B Coil spring 10 First end turn portion 11 First seat surface 20 Second end turn portion 21 Second seat surface 30 Central turn portion 51 First reference point 52 Second reference point 111 First turn end portion edge region 112 First end winding transition area

Claims (2)

A first end turn portion provided on one side in the axial direction and having a first seat surface facing one side in the axial direction is formed, and a second seat surface provided on the other side in the axial direction and facing the other side in the axial direction is formed. A coil spring having a second end turn portion and a center turn portion between the first and second end turn portions,
The first end winding portion extends from a first end portion on one side in the axial direction to a portion forming a first reference point where a line gap in a natural length state is zero on one side in the axial direction. A winding edge region and a first winding transition region extending from the first end winding edge region to the central winding,
The first end turn edge region is bent toward one axial side of the coil spring as compared to the first end turn transition region,
A coil spring, wherein the first bearing surface is formed so as to straddle the first end turn edge region and the first end turn transition region. The second end winding portion extends from the second end portion on the other side in the axial direction to a portion forming a second reference point where the line gap in the natural length state is zero on the other side in the axial direction. A winding edge region, a second winding transition region extending from the second winding edge region to the central winding,
The second end turn edge region is bent toward the other axial side of the coil spring as compared to the second end turn transition region,
The coil spring according to claim 1, wherein the second bearing surface is formed so as to straddle the second end winding portion edge region and the second end winding portion transition region.