CN108729273A

CN108729273A - Steel cord, tire

Info

Publication number: CN108729273A
Application number: CN201711284542.6A
Authority: CN
Inventors: 中岛彻也; 松冈映史
Original assignee: Sumitomo Electric Tochigi Co Ltd
Current assignee: Sumitomo Electric Tochigi Co Ltd
Priority date: 2017-04-20
Filing date: 2017-12-07
Publication date: 2018-11-02
Anticipated expiration: 2037-12-07
Also published as: JP2018178332A; JP6980965B2; CN108729273B

Abstract

A kind of steel cord of present invention offer, tire, excellent impact resistance.Steel cord has the 1 × n structures for being twisted n roots (n=3 or 4) bare wire, in the section vertical with length direction, when the area of maximum circumcircle is set as S1 and the area of bare wire is set as S2, the voidage V indicated by formula below (A) is 37% or more and 60% hereinafter, V (%)=(S1-nS2)/S1 × 100 (A).

Description

Steel cord, tire

Technical field

The present invention relates to a kind of steel cord, tires.

Background technology

Pass through the equal steel cord that tire is used for known as reinforcement material of patent document 1.In patent document 1, for steel Cord, it is proposed that following content：Be recessed to when concave-convex with stone on driving to road etc. absorb impact to a certain degree and For the purpose of the deformation for preventing tire when high speed rotation, for the load and elongation of steel cord, scheduled relationship is formed.

Existing technical literature

Patent document

Patent document 1：Japanese Unexamined Patent Publication 2002-275772 bulletins

Invention content

However, in recent years, from the viewpoint of the durability of impact when improving tire to driving to the bump on road surface etc. It sets out, steel cord requires the raising of impact resistance.

However, tire reinforcement disclosed in patent document 1 is predetermined by making load and elongation be formed with steel cord Relationship, absorb impact without make vehicle taking sense reduce in the case of want inhibit high speed rotation when tire become Shape.Therefore, research is not made fully in the viewpoint of impact resistance.

Therefore, the disclosure is designed to provide a kind of steel cord of excellent impact resistance.

According to the disclosure viewpoint, provide a kind of steel cord, the steel cord, which has, is twisted n root bare wires The area of maximum circumcircle is being set as S1 and incited somebody to action by 1 × n structures, wherein n=3 or 4 in the section vertical with length direction When the area of bare wire is set as S2, the voidage V indicated by formula below (A) is for 37% or more and 60% hereinafter, V (%)=(S1- nS2)/S1×100…(A)。

Moreover, according to another viewpoint of the disclosure, a kind of steel cord is provided, the steel cord, which has, is twisted n root bare wires Made of 1 × n structures, wherein n=5, in the section vertical with length direction, by the area of maximum circumcircle be set as S1 and When the area of bare wire is set as S2, the voidage V that is indicated by formula below (A) be 33% or more and 55% hereinafter, V (%)= (S1-nS2)/S1×100…(A)。

According to the disclosure, it is capable of providing the steel cord of excellent impact resistance.

Description of the drawings

Fig. 1 is the definition graph of the steel cord of 1 × 4 structure of a form of the disclosure.

Fig. 2 is the sectional view at the face vertical with length direction of the steel cord of Fig. 1.

Fig. 3 is the section view at the face vertical with length direction of the steel cord of 1 × 3 structure of a form of the disclosure Figure.

Fig. 4 is the section view at the face vertical with length direction of the steel cord of 1 × 5 structure of another form of the disclosure Figure.

Fig. 5 is the definition graph of Charpy-type test.

Fig. 6 is the definition graph for the bare wire for being repeatedly formed bending part and non-bending part.

Fig. 7 is the definition graph of the manufacturing method for the bare wire for being repeatedly formed bending part and non-bending part.

Fig. 8 is the sectional view of the tire of a form of the disclosure.

Fig. 9 is the figure for schematically showing belt.

Figure 10 is the figure of the voidage and the relationship of impact absorbing index that indicate 1~experimental example of experimental example 11.

Figure 11 is the figure of the central area area and the relationship of impact absorbing index that indicate 1~experimental example of experimental example 11.

Figure 12 is the figure of the voidage and the relationship of impact absorbing index that indicate 12~experimental example of experimental example 16.

Figure 13 is the figure of the central area area and the relationship of impact absorbing index that indicate 12~experimental example of experimental example 16.

Figure 14 is the figure of the voidage and the relationship of impact absorbing index that indicate 17~experimental example of experimental example 26.

Figure 15 is the figure of the central area area and the relationship of impact absorbing index that indicate 17~experimental example of experimental example 26.

Label declaration

10,30,40,91 steel cord

11,61,72 bare wire

12 central part gaps

Gap between 13 bare wires

14 maximum circumcircles

15 central areas

51 samples

52 hammers

53 rotary shafts

A initial positions

B maximum heights position

62,62A, 62B, 62C bending part

63 non-bending parts

Repetition interval between P bending parts and non-bending part

The difference of the height of bending part adjacent h

71 preformed members

81 tires

82 fetus faces

83 sidewalls

84 bead parts

85 linings

86 carcasses

87 belts

88 steel bead wires

92 rubber.

Specific implementation mode

Hereinafter, mode of the explanation for implementation.

[explanation of embodiment of the present disclosure]

The implementation form of the disclosure is enumerated first to illustrate.In the following description, it is wanted for identical or corresponding Element marks identical label, and does not repeat identical explanation for these elements.

(1) steel cord of a form of the disclosure has the 1 × n structures for being twisted n roots (n=3 or 4) bare wire, In the section vertical with length direction, when the area of maximum circumcircle is set as S1 and the area of bare wire is set as S2, by The voidage V that formula (A) below indicates is 37% or more and 60% or less.

V (%)=(S1-nS2)/S1 × 100 ... (A)

The research of inventors according to the present invention is inferred as 1 × 3 structure or 1 by making voidage V be 37% or more Multiple bare wires that the steel cord of × 4 structures is included have integraty and can overcome the impact being applied in, and the sky in steel cord Gap can absorb the impact being applied in.

But if voidage V is more than 60%, multiple bare wires that the steel cord of 1 × 3 structure or 1 × 4 structure is included Between distance become larger, therefore integraty between bare wire weakens, and is inferred as multiple bare wires that steel cord is included and is easy due to impact And it is individually cut off.

Therefore, according to the steel cord of the disclosure form, by make above-mentioned voidage V be 37% or more and 60% with Under, the steel cord of excellent impact resistance can be formed.

(2) in addition, there is the steel cord of another form of the disclosure the 1 × n for being twisted n roots (n=5) bare wire to tie Structure, in the section vertical with length direction, when the area of maximum circumcircle is set as S1 and the area of bare wire is set as S2, It is 33% or more and 55% or less by the voidage V that formula below (A) indicates.

V (%)=(S1-nS2)/S1 × 100 ... (A)

The research of inventors according to the present invention is inferred as the steel of 1 × 5 structure by making voidage V be 33% or more Multiple bare wires that cord is included have integraty and can overcome the impact being applied in, and the gap in steel cord can absorb quilt The impact of application.

But, when voidage V is more than 55%, the distance between multiple bare wires that the steel cord of 1 × 5 structure is included becomes Greatly, integraty therefore between bare wire weakens, be inferred as multiple bare wires that steel cord is included be easy due to impact and individually by Cut-out.

Therefore, according to the steel cord of another form of the disclosure, by making above-mentioned voidage V be 33% or more and 55% Hereinafter, the steel cord of excellent impact resistance can be formed.

(3) there is 1 × 3 structure for being twisted 3 bare wires, in the section vertical with length direction, by inciting somebody to action The face in the region that the straight line linked between the center along the adjacent bare wire of circumferencial direction of the maximum circumcircle surrounds Product can be 0.07mm²Above and 0.13mm²Below.

(4) there is 1 × 3 structure for being twisted 3 bare wires, 1 × 3 knot for being 35.8% with the voidage V Impact when being worth on the basis of the charp impact value of the steel cord of structure, expression charp impact value is relative to the ratio of a reference value Absorption index can be more than 100% and be 110% or less.

(5) there is 1 × 4 structure for being twisted 4 bare wires, the section at the face vertical with length direction In, by the area that will be surrounded along the straight line linked between the center of the adjacent bare wire of circumferencial direction of the maximum circumcircle The area in domain can be 0.16mm²Above and 0.32mm²Below.

(6) there is 1 × 4 structure for being twisted 4 bare wires, 1 × 4 knot for being 36.4% with the voidage V Impact when being worth on the basis of the charp impact value of the steel cord of structure, expression charp impact value is relative to the ratio of a reference value Absorption index can be more than 100% and be 140% or less.

(7) there is 1 × 5 structure for being twisted 5 bare wires, in the section vertical with length direction, by inciting somebody to action The face in the region that the straight line linked between the center along the adjacent bare wire of circumferencial direction of the maximum circumcircle surrounds Product can be 0.24mm²Above and 0.45mm²Below.

(8) there is 1 × 5 structure for being twisted 5 bare wires, 1 × 5 knot for being 32.0% with the voidage V Impact when being worth on the basis of the charp impact value of the steel cord of structure, expression charp impact value is relative to the ratio of a reference value Absorption index can be more than 100% and be 115% or less.

(9) at least 1 bare wire in bare wire described in n roots can repeat have bending part and non-bending along its length Portion.

(10) bare wire described in n roots can all repeat have bending part and non-bending part along its length.

(11) by the bare wire place in the plane when from the plane to the institute of the side away from the plane farther out In the case that height until stating bending part is defined as kink height, the kink height can be 0.10mm or more and 0.30mm Below.

(12) repetition interval between the bending part and the non-bending part can be 5.0mm or more and 30.0mm with Under.

(13) initial elongation degree when being applied with 49N can be 0.06% or more and 0.35% or less.

(14) diameter of the bare wire can be 0.22mm or more and 0.42mm or less.

(15) it can be set as including the tire of the steel cord of any record in (1)~(14).

[embodiment of the present disclosure detailed]

Hereinafter, with reference to attached drawing, illustrate an embodiment (being denoted as below " present embodiment ") for the disclosure steel cord, The concrete example of tire.In addition, the present invention is not limited to above-mentioned illustration, but indicated by claims, it is intended that include Whole changes in the meaning and range being equal with claims.

(steel cord)

Hereinafter, being based on Fig. 1~Fig. 7, illustrate the steel cord of present embodiment.

The steel cord of present embodiment is referred to as 1 × n knots made of the bare wire of silk thread with n roots are spirally twisted Structure.

Here, Fig. 1 shows a configuration example of the steel cord 10 of present embodiment.Steel cord 10 shown in FIG. 1 has 4 The structure that root bare wire 11 is twisted.

Also, 1 × n structures refer to that n root bare wires are twisted into the structure of single layer (1 layer).Single layer refer to Fig. 2 as be described hereinafter or Shown in Fig. 3, Fig. 4 in the section vertical with length direction of steel cord bare wire along 1 round circumferencial direction be in single layer (1 layer) The structure of arrangement.

4 bare wires 11 are twisted into single layer and form 1 × 4 structure by steel cord 10 shown in FIG. 1.Steel cord shown in FIG. 1 Sectional view at 10 face vertical with length direction is as shown in Figure 2.In addition, the length direction of steel cord 10 is the Y-axis in figure Direction.Moreover, the face vertical with length direction is the face parallel with the XZ planes in figure.

As shown in Fig. 2, 4 bare wires 11 are twisted, the central part gap 12 surrounded by 4 bare wires 11 is formed in central part.

In fig. 2, in the section vertical with length direction, the example that adjacent bare wire 11 contacts is shown, but also may be used As the case where steel cord 30,40 of Fig. 3, Fig. 4 as be described hereinafter, some or all of adjacent bare wire 11 do not contact and Gap is formed between bare wire 11.

Fig. 3 shows the configuration example of the sectional view at the face vertical with length direction of the steel cord 30 of 1 × 3 structure.Moreover, Fig. 4 shows the configuration example of the sectional view at the face vertical with length direction of the steel cord 40 of 1 × 5 structure.

3 bare wires 11 are twisted into single layer by the steel cord 30 of 1 × 3 structure shown in Fig. 3, are formed in central part naked by 3 The central part gap 12 that line 11 surrounds.5 bare wires 11 are twisted into single layer by the steel cord 40 of 1 × 5 structure shown in Fig. 4, in Center portion is formed with the central part gap 12 surrounded by 5 bare wires 11.

In Fig. 3, Fig. 4, it is formed with gap 13 between bare wire between adjacent bare wire 11, but one of adjacent bare wire 11 Point or all can steel cord 10 for example shown in Fig. 2 contact like that.

Also, the steel cord of present embodiment is with 1 × 3 structure or in the case of 1 × 4 structure, with length direction In vertical section, when the area of maximum circumcircle is set as S1 and the area of each bare wire is set as S2, by below The voidage V that formula (A) indicates is 37% or more and 60% or less.

In addition, the steel cord of present embodiment is with 1 × 5 structure, in the section vertical with length direction In, when the area of maximum circumcircle is set as S1 and the area of each bare wire is set as S2, indicated by formula below (A) Voidage V is 33% or more and 55% or less.

A (%)=(S1-nS2)/S1 × 100 ... (A)

Here, in the case of the section of the steel cord 10 of 1 × 4 structure shown in Fig. 2, steel cord is hung down with length direction Maximum circumcircle at straight section refers to the maximum circumcircle 14 of the outer peripheral edge inscribe of 4 bare wires 11.Moreover, shown in Fig. 3 Steel cord 30 section in the case of, refer to the maximum circumcircle 14 of the outer peripheral edge inscribe of 3 bare wires 11.It is shown in Fig. 4 Refer to the maximum circumcircle 14 of the outer peripheral edge inscribe of 5 bare wires 11 in the case of the section of steel cord 40.No matter in which kind of situation Under, maximum circumcircle 14 all becomes positive round.

Maximum circumcircle 14 also corresponds to the shape of steel cord, therefore in the present specification, sometimes by maximum circumcircle 14 Diameter be known as cord diameter.

Also, voidage V expressions are surrounded in the section vertical with length direction of steel cord by maximum circumcircle 14 The ratio of the area in the region that the bare wire 11 in region does not occupy can be calculated by above-mentioned formula (A).In addition, in same steel In cord, voidage at the section vertical with length direction of steel cord independent of the position in the section of measurement but it is constant , therefore the section of the arbitrary position of the length direction of steel cord can be used to be measured, calculate.

Voidage V at the section vertical with length direction of steel cord can be for example, by already described adjacent bare wire 11 Between bare wire between the presence or absence of gap 13 or its size, the size in central part gap 12 etc. and be adjusted.

The method of impact resistance as evaluation steel cord, can enumerate Charpy-type test.About Charpy-type test, example Such as, it as shown in figure 5, can be rotated centered on rotary shaft 53 from initial position A by making the hammer 52 of quality m, will install in advance Sample 51 on the mobile route of hammer 52 makes implementation down.Hammer 52 destroys sample 51 later further along direction of rotation row Into arrival maximum height position B.

Here, the height of the initial position A using the position of sample 51 as benchmark is set as h1, it will be with the position of sample 51 The height of maximum height position B as benchmark is set as h2.In this case, the position energy and maximum height of initial position A Difference, that is, mg (h1-h2) of the position energy of position B becomes absorption energy when destroying sample.Above-mentioned absorption energy is Charpy punching Value is hit, numerical value is bigger, then it represents that be the more excellent steel cord of impact resistance.

Charpy-type test can evaluate the energy needed for the destruction of sample, therefore in order to evaluate the various wire rods such as piano wire Impact resistance and be widely used.In the past, for charp impact value, the elongation or breaking load of the main material for considering wire rod Influence, the influence for the structure of wire rod etc. is unknown.

However, the research of inventors according to the present invention, in the steel cord with 1 × 3 structure or 1 × 4 structure, with The case where voidage V is less than 37% is compared, by making voidage V be able to confirm that Charpy impact for 37% or more and 60% or less The case where value increases.Moreover, in the steel cord with 1 × 5 structure, compared with the case where voidage V is less than 33%, by making Voidage V is able to confirm that the case where charp impact value increases for 33% or more and 55% or less.That is, for being tried with Charpy impact Test the impact resistance of evaluation, it was found that the influence of the structure of the wire rod as sample.

This be inferred to be due to, by make steel cord voidage V be above-mentioned predetermined value corresponding with structure more than, Multiple bare wires that steel cord is included have integraty and can overcome the impact being applied in, and the gap in steel cord absorbs and applied The impact added.

But, in the steel cord with 1 × 3 structure or 1 × 4 structure, if the voidage V of steel cord is more than 60%, Distance between multiple bare wires that then steel cord is included becomes larger, it can thus be assumed that the integraty between bare wire weakens.Therefore, steel cord Including multiple bare wires be easy individually be cut off due to impact, it is inferred that for impact resistance decline.

In addition, in the steel cord with 1 × 5 structure, when the voidage V of steel cord is more than 55%, for same Reason, deducibility decline for impact resistance.

As described above, the steel cord of present embodiment can be by making voidage V improve resistance to punching in scheduled range Hitting property.Therefore, in the section vertical with length direction of steel cord, preferably in a manner of so that voidage V is in above range Adjust the configuration etc. of multiple bare wires.

In addition, as shown in Figure 2 to 4, the steel cord about present embodiment, it is preferred that steel cord and length In the vertical section in direction, there is the gap, that is, central part gap 12 surrounded by bare wire in central part.This is because, can pass through Central part gap 12 is impacted to absorb, and can especially improve impact resistance.Therefore, the steel cord of present embodiment preferably has 3 or more bare wires.But, when the radical of bare wire is more than 5, need to make the i.e. bare wire diameter of diameter of bare wire to attenuate and make system This increase is caused, therefore not preferably.Therefore, the steel cord of present embodiment preferably comprises 3 or more and 5 bare wires below.

In order to improve impact resistance, also contemplate for that steel cord is made to be formed as not to be single layer but two layers or more of multilayer strand twirl Structure, but it is also possible that result in the need for making the bare wire diameter of each layer to attenuate, twisting process become 2 processes with first-class manufacture Complication in process.Therefore, the steel cord of present embodiment is preferably the single layer structure of 1 × n structures.In addition, multilayer refers to Such as lower structure：In the section vertical with length direction of steel cord, by bare wire is arranged along 1 round circumferencial direction 1 layer is formed, and the layer has multilayer in concentric circles.

In the case where the radical n for the bare wire that the steel cord of present embodiment contains is 3, vertical with length direction In section, by will be along the region that the straight line that links between the center of the adjacent bare wire of the circumferencial direction of maximum circumcircle surrounds Area is preferably 0.07mm²Above and 0.13mm²Below.

At the section vertical with length direction when radical n about bare wire is 3 by will be along maximum circumcircle The region (hereinafter, being also recorded as " central area ") that the straight line linked between the center of the adjacent bare wire of circumferencial direction surrounds, profit It is illustrated with Fig. 3.Fig. 3 shows the vertical with length direction of the steel cord 30 that the radical of already described such bare wire 11 is 3 Sectional view at face.When the radical n of the bare wire of steel cord is 3, if will be along the circle of maximum circumcircle 14 using straight line Link between the center of the adjacent bare wire 11 of circumferential direction, is then formed by line segment O₃₁-O₃₂, line segment O₃₂-O₃₃, line segment O₃₃-O₃₁It surrounds Triangle central area 15.

In the radical n of bare wire be 3 and the area of central area 15 is 0.07mm as described above²When above, it can be formed The steel cord of excellent impact resistance, therefore preferably.

In the radical n of bare wire be 3 and the area of central area 15 is 0.07mm²When above, it is believed that central area 15 Including being enough to absorb the central part gap 12 of the size of impact.It therefore, can be in when being applied with impact to steel cord 30 Heart district domain 15 fully absorbs impact, is inferred as that impact resistance can be improved.

But, when the radical n of bare wire is 3, it is believed that if the area of central area 15 is more than 0.13mm², then Distance between bare wire also becomes larger, therefore the integraty between bare wire weakens.Therefore, multiple bare wires 11 that steel cord 30 is included are easy It is individually cut off due to impact, impact resistance may decline.Therefore, when the radical n of bare wire is 3, central area 15 area is preferably 0.13mm²Below.

In addition, when the radical n of bare wire that contains of steel cord of present embodiment is 4, vertical with length direction In section, by will be along the region that the straight line that links between the center of the adjacent bare wire of the circumferencial direction of maximum circumcircle surrounds Area is preferably 0.16mm²Above and 0.32mm²Below.

Central area when radical n about bare wire is 4, is illustrated using Fig. 2.In Fig. 2, for already described such The steel cord 10 that the radical of bare wire 11 is 4, shows the sectional view at the face vertical with length direction.In the bare wire of steel cord When radical n is 4, if will be connected along between the center of the adjacent bare wire 11 of the circumferencial direction of maximum circumcircle 14 using straight line Knot is then formed by line segment O₁₁-O₁₂, line segment O₁₂-O₁₃, line segment O₁₃-O₁₄, line segment O₁₄-O₁₁The central area of the quadrangle of encirclement 15。

In the radical n of bare wire be 4 and the area of central area 15 is 0.16mm as described above²When above, it can be formed The steel cord of excellent impact resistance, therefore preferably.

In the radical n of bare wire be 4 and the area of central area is 0.16mm²When above, it is believed that wrap central area 15 Containing being enough to absorb the central part gap 12 of the size of impact.Therefore, in the case where being applied with impact to steel cord 10, Neng Goutong It crosses central area 15 and fully absorbs impact, be inferred as that impact resistance can be improved.

But when the radical n of bare wire is 4, it is believed that if the area of central area 15 is more than 0.32mm², then Distance between bare wire also becomes larger, therefore the integraty between bare wire weakens.Therefore, steel cord is included multiple bare wires be easy due to It impacts and is individually cut off, impact resistance may decline.Therefore, when the radical n of bare wire is 4, central area 15 Area is preferably 0.32mm²Below.

In addition, when the radical n of bare wire that contains of steel cord of present embodiment is 5, vertical with length direction In section, by will be along the region that the straight line that links between the center of the adjacent bare wire of the circumferencial direction of maximum circumcircle surrounds Area is preferably 0.24mm²Above and 0.45mm²Below.

Central area when radical n about bare wire is 5, is illustrated using Fig. 4.In Fig. 4, for already described such The steel cord 40 that the radical of bare wire is 5, shows the sectional view at the face vertical with length direction.In the root of the bare wire of steel cord When number n is 5, if will be connected along between the center of the adjacent bare wire 11 of the circumferencial direction of maximum circumcircle 14 using straight line Knot is then formed by line segment O₄₁-O₄₂, line segment O₄₂-O₄₃, line segment O₄₃-O₄₄, line segment O₄₄-O₄₅, line segment O₄₅-O₄₁That surrounds is pentagonal Central area 15.

In the radical n of bare wire be 5 and the area of central area 15 is 0.24mm as described above²When above, it can be formed The steel cord of excellent impact resistance, therefore preferably.

In the radical n of bare wire be 5 and the area of central area is 0.24mm²When above, it is believed that wrap central area 15 Containing being enough to absorb the central part gap 12 of the size of impact.It therefore, can be by above-mentioned when being applied with impact to steel cord 40 Central area fully absorbs impact, is inferred as that impact resistance can be improved.

But when the radical n of bare wire is 5, it is believed that if the area of central area 15 is more than 0.45mm², then Distance between bare wire also becomes larger, therefore the integraty between bare wire weakens.Therefore, steel cord is included multiple bare wires be easy due to It impacts and is individually cut off, impact resistance may decline.Therefore, when the radical n of bare wire is 5, the face of central area Product is preferably 0.45mm²Below.

At least 1 bare wire in the bare wire for the n roots that the steel cord of present embodiment contains can repeat to have along its length There are bending part and non-bending part.Moreover, the n roots bare wire that the steel cord of present embodiment contains can all repeat along its length With bending part and non-bending part.

Fig. 6 is schematically shown repeats the bare wire 61 with bending part and non-bending part along its length.It is shown in fig. 6 naked Line 61 alternately repeats have bending part 62 and non-bending part 63 along its length.

In addition, in fig. 6, it is illustrated that example at bending part 62 to be bent close to 90 degree of angle, but do not limit For aforesaid way, can also be, to be, for example, less than that 90 degree or angle more than 90 degree are bent.Moreover, at bending part 62, bare wire There need not be specific inflection point, there can be the shape for example in arc-shaped being bent.

1 in bare wire by making n roots that the steel cord of present embodiment contains or more bare wires have along length side To the shape with bending part and non-bending part is repeated, voidage V can be adjusted.Therefore, it is possible to select obtained steel cord Impact resistance degree.

But, steel cord is by including the bare wire for repeating the shape with bending part and non-bending part along its length, no Voidage V is only influenced, and the characteristic of initial elongation degree etc. is also had an impact.It is therefore preferable that according to required by steel cord Voidage V, the characteristics such as initial elongation degree, there is bending part and non-bending come repeating along its length of selecting that steel cord contains The radical and its shape of the bare wire in portion.

In repeating the bare wire with bending part and non-bending part along its length, the weight between bending part and non-bending part Multiple spacing is preferably 5.0mm or more and 30.0mm hereinafter, more preferably 5.0mm or more and 20.0mm or less.

Repetition interval of the bending part between non-bending part refer to same shape bending part between at a distance from, refer to from conduct The length of the length direction of steel cord until the bending part of benchmark to two adjacent bending parts.Therefore, example shown in Fig. 6 In son, the repetition interval P between bending part and non-bending part refers to for example from bending part 62A to two adjacent bending part Distance until 62C.

It is 5.0mm or more by making the repetition interval between bending part and non-bending part, is easy to form bending part in bare wire With non-bending part, and be easy according to the voidage V for requiring and accurately controlling steel cord, therefore preferably.But, if it is desired to Make the repetition interval ratio 30.0mm long between bending part and non-bending part, is then used to form the device meeting of bending part and non-bending part Enlargement, manufacturing cost may increase.

In addition, until the bending part 62B of sides of slave plane S when bare wire to be positioned over to plane S to anomaly face S farther out Height is set as kink height h.

Kink height h is preferably 0.10mm or more and 0.30mm hereinafter, more preferably 0.12mm or more and 0.28mm or less.

This is because, by the way that kink height h is set as 0.10mm or more, gap can be especially improved when forming steel cord Rate V.But, if making kink height h ratio 0.30mm long, other bare wires may be damaged when bare wire to be twisted each other.Cause This, kink height h is preferably 0.30mm or less.

It for example can be more by configuring as shown in fig. 7, repeating the bare wire with bending part and non-bending part along its length A preformed member 71 simultaneously makes bare wire 72 be formed across multiple preformed members 71.By change preformed member 71 configuration, Size, shape and the shape of bending part, the length etc. of non-bending part can be selected.Preformed member 71 can have such as pin-type The shape of (cylindrical type) or gear type.

The diameter for the bare wire that the steel cord of present embodiment is included i.e. bare wire diameter be preferably 0.22mm or more and 0.42mm is hereinafter, more preferably 0.25mm or more and 0.38mm or less.

By making a diameter of 0.22mm or more of bare wire, for the steel cord comprising the bare wire, fracture can be fully improved Load.

But, if bare wire diameter is excessively thick, including the steel cord of the line, used steel cord tire weight increase Greatly, to not preferred.Therefore, bare wire diameter is preferably 0.42mm or less.

Initial elongation degree of the steel cord of present embodiment when being applied with 49N be preferably 0.06% or more and 0.35% with Under, more preferably 0.07% or more and 0.30% or less.

Initial elongation degree refers to that after steel cord is made in strand twirl bare wire, which attached load along its length Elongation when lotus.Initial elongation degree is spirally to twist multiple bare wires of twirl to be close to shape reaching due to being applied in load The elongation generated during state.When the steel cord that above-mentioned initial elongation degree is directed to present embodiment is applied with 49N The ratio of elongation of the steel cord per 500mm.

The steel cord of present embodiment can for example be embedded in tire used as described later.By the steel for making present embodiment The initial elongation degree of cord is 0.06% or more, has the tire of the steel cord for embedment, can improve the absorption of road surface bumps Performance, that is, shock absorbing capability can improve taking sense.But, it if the initial elongation degree of steel cord is more than 0.35%, twists Processing workability in line procedures etc. may decline, therefore preferably 0.35% or less.

It is influenced by the temperature of surrounding, humidity by charp impact value that already described Charpy-type test measures.Cause This, the result of Charpy-type test is denoted as the relative scale of the charp impact value relative to the primary standard substance as benchmark.

Specifically, determining for said reference object and to comment as the primary standard substance of benchmark when carrying out Charpy-type test Valence object carries out Charpy-type test under identical environment.Also, it is worth (100%) on the basis of the charp impact value of primary standard substance, with The charp impact value of object is evaluated relative to ratio, that is, impact absorbing exponential representation of a reference value.It is in impact absorbing index In the case of 100%, indicate that charp impact value is identical with evaluation object in primary standard substance.

In the steel cord of present embodiment, the steel cord of excellent impact resistance can be formed by selecting voidage V. Therefore, in the case where confirming the effect of above-mentioned voidage V, primary standard substance when for calculating impact absorbing index and evaluation object, Preferably, the bare wire diameter for the bare wire that steel cord is included is identical.

The steel cord of present embodiment containing bare wire radical n be 3 when, impact absorbing index can use gap The charp impact value of the steel cord for 1 × 3 structure that rate V is 35.8% is as a reference value.Also, in the steel cord of present embodiment When the radical n of the bare wire contained is 3, said reference value refers to relative to ratio, that is, impact absorbing of the percentage of charp impact value Number is preferably greater than 100% and is 110% or less.By making above-mentioned impact absorbing index be more than 100% and for 110% hereinafter, energy Enough form the steel cord of excellent impact resistance.

The steel cord for 1 × 3 structure that the voidage V of primary standard substance as impact absorbing index is 35.8% can for example incite somebody to action 3 bare wires for not being pre-formed bending part and non-bending part are twisted and make.Steel cord of the above-mentioned steel cord in 1 × 3 structure In the case of voidage V it is smaller.

Also, the research of inventors according to the present invention can improve the resistance to punching of steel cord by improving voidage V Hitting property.Therefore, the impact absorbing index on the basis of the steel cord of voidage V 1 × 3 structures for being 35.8% is preferably greater than 100%.

But, it if it is desired that above-mentioned impact absorbing index is more than 110%, then is not only to require such as voidage V, Er Qieyou When be also required to keep bare wire diameter thicker etc..If bare wire diameter is thicker, steel cord, used the steel cord tire weight Increase, to not preferred.Therefore, impact absorbing index is preferably 110% or less.

The steel cord of present embodiment containing bare wire radical n be 4 when, impact absorbing index can use gap The charp impact value of the steel cord for 1 × 4 structure that rate V is 36.4% is as a reference value.Also, the steel cord of present embodiment exists When the radical n of the bare wire contained is 4, said reference value refers to relative to ratio, that is, impact absorbing of the percentage of charp impact value Number is preferably greater than 100% and is 140% or less.By making above-mentioned impact absorbing index be more than 100% and for 140% hereinafter, energy Enough form the steel cord of excellent impact resistance.

The steel cord for 1 × 4 structure that the voidage V of benchmark as impact absorbing index is 36.4% for example can will be pre- 4 bare wires for not forming bending part and non-bending part first are twisted and make.Feelings of the above-mentioned steel cord in the steel cord of 1 × 4 structure Voidage V is smaller under condition.

Also, the research of inventors according to the present invention can improve the resistance to punching of steel cord by improving voidage V Hitting property.Therefore, the impact absorbing index on the basis of the steel cord of voidage V 1 × 4 structures for being 36.4% is preferably greater than 100%.

But, it if above-mentioned impact absorbing index is wanted to be more than 140%, is not only to require such as voidage V, and sometimes Need to keep bare wire diameter thicker etc..If bare wire diameter is thicker, steel cord has used the weight of the tire of the steel cord to increase Add, to not preferred.Therefore, impact absorbing index is preferably 140% or less.

The steel cord of present embodiment containing bare wire radical n be 5 when, impact absorbing index can use gap The charp impact value of the steel cord for 1 × 5 structure that rate V is 32.0% is as a reference value.Also, the steel cord of present embodiment exists When the radical n of the bare wire contained is 5, said reference value refers to relative to ratio, that is, impact absorbing of the percentage of charp impact value Number is preferably greater than 100% and is 115% or less.By making above-mentioned impact absorbing index be more than 100% and for 115% hereinafter, energy Enough form the steel cord of excellent impact resistance.

The steel cord for 1 × 5 structure that the voidage V of benchmark as impact absorbing index is 32.0% for example can will be pre- 5 bare wires for not forming bending part and non-bending part first are twisted and make.Feelings of the above-mentioned steel cord in the steel cord of 1 × 5 structure Voidage V is smaller under condition.

Also, the research of inventors according to the present invention can improve the resistance to punching of steel cord by improving voidage V Hitting property.Therefore, the impact absorbing index on the basis of the steel cord of voidage V 1 × 5 structures for being 32.0% is preferably greater than 100%.

But, it if above-mentioned impact absorbing index is wanted to be more than 115%, is not only to require such as voidage V, and sometimes Be also required to keep bare wire diameter thicker etc..If bare wire diameter is thicker, steel cord has used the weight of the tire of the steel cord to increase Add, to not preferred.Therefore, impact absorbing index is preferably 115% or less.

(tire)

Next, being illustrated to the tire of present embodiment based on Fig. 8, Fig. 9.

The tire of present embodiment can include already described steel cord.

Fig. 8 shows the sectional view at the face vertical with circumferential direction of the tire 81 of present embodiment.It only shows to compare CL in fig. 8 (center line) leans on the part in left side, but also continuously has same structure on the right side of CL using CL as symmetry axis.

As shown in figure 8, tire 81 has fetus face 82, sidewall 83 and bead part 84.

Fetus face 82 is the position contacted with road surface.Bead part 84 is set to the internal side diameter by tire 81 than fetus face 82 Position.Bead part 84 is the position contacted with the wheel rim of the wheel of vehicle.Fetus face 82 is connect by sidewall 83 with bead part 84. When fetus face 82 receives to impact from road surface, flexible deformation occurs for sidewall 83, absorbs impact.

Tire 81 has lining 85, carcass 86, belt 87 and steel bead wire 88.

Lining 85 is made of rubber, by the airtight space between tire 81 and wheel.

Carcass 86 forms the skeleton of tire 81.Carcass 86 is by the organic fibers such as polyester, nylon, artificial silk or steel cord and rubber Glue is constituted.

Steel bead wire 88 is set to bead part 84.Steel bead wire 88 bears to act on the drawing force of carcass.

Belt 87 fastens carcass 86, improves the rigidity of fetus face 82.In the example shown in Fig. 8, tire 81 has two Layer belt 87.

Fig. 9 is the figure for schematically showing two layers of belt 87.Fig. 9 belt 87 is shown with the length direction i.e. week of tire 81 Sectional view at vertical face.

As shown in figure 9, two layers of belt 87 is overlapped along the radial direction of tire 81.Each belt 87 has more steel cords 91 and rubber 92.More steel cords 91 are arranged in a row.Moreover, rubber 92 coats steel cord 91, respectively by rubber on each steel cord complete cycle Glue 92 covers.Steel cord 91 is embedded in rubber 92.

Tire according to the present embodiment, including the steel cord of already described excellent impact resistance is as steel cord 91.Therefore, About the tire of present embodiment, the tire of excellent impact resistance can be also formed.

More than, embodiment is described in detail, but it is not limited to specific embodiment, it is recorded in claims Various modifications and change can be carried out in range.

Embodiment

It is illustrated hereinafter, enumerating specific embodiment, but the present invention is not limited to these embodiments.

(evaluation method)

First, illustrate the evaluation method of the manufactured steel cord in experimental example below.

(1) bare wire diameter

Bare wire diameter is measured using micrometer.

(2) cord diameter

The steel cord evaluated is embedded in transparent resin, by sample so that the face vertical with length direction of steel cord The mode that (section) exposes is cut out.

Then, the circumscribed diameter of a circle of maximum that the more bare wires that above-mentioned section is included are measured using projection device, as Cord diameter.

(3) voidage

According to bare wire diameter and cord diameter that utilization (1), (2) measure, the area S1 of maximum circumcircle and each is calculated The area S2 of root bare wire calculates voidage V using formula below (A).

V (%)=(S1-nS2)/S1 × 100 ... (A)

(4) central area area

The observation in the section vertical with length direction of the steel cord measured when according to the cord diameter of calculating (2) as a result, Calculate using straight line by along the region to link between the center of the adjacent bare wire of the circumferencial direction of maximum circumcircle i.e. in The area in heart district domain.

(5) initial elongation degree

Use Autograph (Shimadzu Scisakusho Ltd's models：AGS-J 1kN), when measuring, calculating application 49N Steel cord per 500mm elongation ratio, as initial elongation degree.

(6) breaking load

Use Autograph (Shimadzu Scisakusho Ltd's models：AGS-H 10kN), along the length direction of steel cord Apply load, the load of steel cord is applied to as breaking load when using fracture.

(7) impact absorbing index

Using Charpy-type test device shown in fig. 5, charp impact value is measured by Charpy-type test, according to survey Fixed charp impact value calculates impact absorbing index.

Specifically, the sample about primary standard substance and evaluation, has carried out Charpy-type test under identical environment.Also, It is worth (100%) on the basis of the charp impact value of primary standard substance, the charp impact value of the sample of evaluation is converted into relative to the base Ratio, that is, impact absorbing index of quasi- value.

In 2~experimental example of experimental example 11, using in experimental example 1 manufactured steel cord as primary standard substance (benchmark cord).

In 13~experimental example of experimental example 16, using in experimental example 12 manufactured steel cord as primary standard substance (benchmark curtain Line).

In 18~experimental example of experimental example 26, using in experimental example 17 manufactured steel cord as primary standard substance (benchmark curtain Line).

(experimental example)

The steel cord for making each experimental example below, has carried out above-mentioned evaluation.In addition, steel cord is twisted using pack Line machine by make strand twist spacing for 17.0mm in a manner of to bare wire carry out twist twirl and it is manufactured.

Experimental example 3~10, experimental example 13~15, experimental example 18~25 be used as embodiment, experimental example 1,2,11,12,16, 17,26 it is used as comparative example.

(1~experimental example of experimental example 11)

As 1~experimental example of experimental example 11, the radical for making contained bare wire is 4 and voidage is different steel curtain Line is evaluated.

[experimental example 1]

Using 4 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 4 structure is made.In addition, 4 Root bare wire has all used the bare wire for not forming bending part and non-bending part.

Evaluation result is as shown in table 1.

[experimental example 2]

Using 4 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 4 structure is made.At this point, 4 1 bare wire in root has used so that kink height h is 0.25mm and the repetition interval P between bending part and non-bending part is The mode of 10mm is formed with the bare wire of bending part and non-bending part.In addition, remaining 3 bare wire used do not formed bending part and The bare wire of non-bending part.Evaluation result is as shown in table 1.

[experimental example 3]

Using 4 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 4 structure is made.At this point, 4 1 bare wire in root has used so that kink height h is 0.30mm and the repetition interval P between bending part and non-bending part is The mode of 10mm is formed with the bare wire of bending part and non-bending part.In addition, remaining 3 bare wire used do not formed bending part and The bare wire of non-bending part.Evaluation result is as shown in table 1.

[experimental example 4]

Using 4 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 4 structure is made.At this point, 4 Root bare wire has all used so that kink height h is 0.25mm and the repetition interval P between bending part and non-bending part is 10mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 5]

Using 4 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 4 structure is made.At this point, 4 Root bare wire has all used so that kink height h is 0.27mm and the repetition interval P between bending part and non-bending part is 14mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 6]

Using 4 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 4 structure is made.At this point, 4 Root bare wire has all used so that kink height h is 0.25mm and the repetition interval P between bending part and non-bending part is 14mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 7]

Using 4 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 4 structure is made.At this point, 4 Root bare wire has all used so that kink height h is 0.28mm and the repetition interval P between bending part and non-bending part is 14mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 8]

Using 4 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 4 structure is made.At this point, 4 Root bare wire has all used so that kink height h is 0.30mm and the repetition interval P between bending part and non-bending part is 12mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 9]

Using 4 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 4 structure is made.At this point, 4 Root bare wire has all used so that kink height h is 0.25mm and the repetition interval P between bending part and non-bending part is 8mm's Mode is formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 10]

Using 4 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 4 structure is made.At this point, 4 Root bare wire has all used so that kink height h is 0.30mm and the repetition interval P between bending part and non-bending part is 14mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 11]

Using 4 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 4 structure is made.At this point, 4 Root bare wire has all used so that kink height h is 0.30mm and the repetition interval P between bending part and non-bending part is 8mm's Mode is formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[table 1]

The voidage of 1~experimental example of experimental example 11 and the relationship of impact absorbing index are as shown in Figure 10 shown in table 1, center The relationship of region area and impact absorbing index is as shown in figure 11.

According to Fig.10, as a result, it is possible to confirm the impact absorbing index relative to voidage in each experimental example Distribution value is at 49.6% in voidage, impact absorbing index obtains peak value on curve of approximation.

In such manner, it is possible to find out between voidage and impact absorbing index there are related, it is able to confirm that empty by selecting Gap rate and the case where improve impact resistance.In turn, it is able to confirm that by making voidage make for 37% or more and 60% or less Impact absorbing index is higher than 100%, excellent impact resistance.

In addition, according to shown in Figure 11 as a result, it is possible to confirm the rushing relative to central area area in each experimental example It hits absorption index to be also distributed about on curve of approximation, in central area, area is 0.220mm²Left and right obtains peak value.

In such manner, it is possible to find out between central area area and impact absorbing index there is also related, therefore it is able to confirm that To the case where improving impact resistance by selecting central area area.In turn, according to containing the radical of bare wire be 4 realities The evaluation result for testing the steel cord of 1~experimental example of example 11 is able to confirm that by making central area area be 0.16mm²Above and 0.32mm²Make impact absorbing index higher than 100% below, excellent impact resistance.

(12~experimental example of experimental example 16)

Next, as 12~experimental example of experimental example 16, make containing the radical of bare wire be 3 and voidage is different Steel cord has been carried out similarly evaluation with the case where 1~experimental example of experimental example 11.

[experimental example 12]

Using 3 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 3 structure is made.In addition, 3 Root bare wire has all used the bare wire for not forming bending part and non-bending part.

Evaluation result is as shown in table 1.

[experimental example 13]

Using 3 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 3 structure is made.At this point, 3 Root bare wire has all used so that kink height h is 0.30mm and the repetition interval P between bending part and non-bending part is 14mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 14]

Using 3 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 3 structure is made.At this point, 3 Root bare wire has all used so that kink height h is 0.25mm and the repetition interval P between bending part and non-bending part is 14mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 15]

Using 3 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 3 structure is made.At this point, 3 Root bare wire has all used so that kink height h is 0.25mm and the repetition interval P between bending part and non-bending part is 10mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 16]

Using 3 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 3 structure is made.At this point, 3 Root bare wire has all used so that kink height h is 0.30mm and the repetition interval P between bending part and non-bending part is 10mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

The voidage of 12~experimental example of experimental example 16 and the relationship of impact absorbing index are as shown in figure 12 shown in table 1, real Central area area and the relationship of impact absorbing index for testing 12~experimental example of example 16 are as shown in figure 13.

According to shown in Figure 12 as a result, it is possible to confirm the value of the impact absorbing index relative to voidage of each experimental example It is distributed on curve of approximation, is 52.5% or so in voidage, impact absorbing index obtains peak value.

In addition, according to shown in Figure 13 as a result, it is possible to confirm the impact relative to central area area of each experimental example Absorption index is also distributed about on curve of approximation, and in central area, area is 0.10mm²Left and right obtains peak value.

In such manner, it is possible to find out between central area area and impact absorbing index there is also related, therefore it is able to confirm that To the case where improving impact resistance by selecting central area area.In turn, according to containing the radical of bare wire be 3 realities The evaluation result for testing the steel cord of 12~experimental example of example 16 is able to confirm that by making central area area be 0.07mm²More than And 0.13mm²Make impact absorbing index than 100% below, excellent impact resistance.

(17~experimental example of experimental example 26)

Next, as 17~experimental example of experimental example 26, make containing the radical of bare wire be 5 and voidage is different Steel cord has been carried out similarly evaluation with the case where 1~experimental example of experimental example 11.

[experimental example 17]

Using 5 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 5 structure is made.In addition, naked Line has used the bare wire for not forming bending part and non-bending part.

Evaluation result is as shown in table 1.

[experimental example 18]

Using 5 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 5 structure is made.At this point, 5 3 bare wires in root have used so that kink height h is 0.30mm and the repetition interval P between bending part and non-bending part is The mode of 14mm is formed with the bare wire of bending part and non-bending part.In addition, remaining 2 bare wire used do not formed bending part and The bare wire of non-bending part.Evaluation result is as shown in table 1.

[experimental example 19]

Using 5 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 5 structure is made.At this point, 5 Root bare wire has all used so that kink height h is 0.28mm and the repetition interval P between bending part and non-bending part is 14mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 20]

Using 5 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 5 structure is made.At this point, 5 Root bare wire has all used so that kink height h is 0.30mm and the repetition interval P between bending part and non-bending part is 14mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 21]

Using 5 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 5 structure is made.At this point, 5 Root bare wire has all used so that kink height h is 0.25mm and the repetition interval P between bending part and non-bending part is 12mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 22]

Using 5 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 5 structure is made.At this point, 5 Root bare wire has all used so that kink height h is 0.25mm and the repetition interval P between bending part and non-bending part is 14mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 23]

Using 5 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 5 structure is made.At this point, 5 Root bare wire has all used so that kink height h is 0.30mm and the repetition interval P between bending part and non-bending part is 12mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 24]

Using 5 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 5 structure is made.At this point, 5 Root bare wire has all used so that kink height h is 0.25mm and the repetition interval P between bending part and non-bending part is 10mm Mode be formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 25]

Using 5 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 5 structure is made.At this point, 5 Root bare wire has all used so that kink height h is 0.24mm and the repetition interval P between bending part and non-bending part is 8mm's Mode is formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

[experimental example 26]

Using 5 bare wires of a diameter of 0.370mm of bare wire, the steel cord for twisting and twisting that structure is 1 × 5 structure is made.At this point, 5 Root bare wire has all used so that kink height h is 0.30mm and the repetition interval P between bending part and non-bending part is 8mm's Mode is formed with the bare wire of bending part and non-bending part.Evaluation result is as shown in table 1.

The voidage of 17~experimental example of experimental example 26 and the relationship of impact absorbing index are as shown in figure 14 shown in table 1, in Heart region area and the relationship of impact absorbing index are as shown in figure 15.

According to shown in Figure 14 as a result, it is possible to confirm the impact absorbing index relative to voidage in each experimental example Distribution value is 42.0% or so in voidage, impact absorbing index obtains peak value on curve of approximation.

In such manner, it is possible to find out between voidage and impact absorbing index there are related, it is able to confirm that empty by selecting Gap rate and the case where improve impact resistance.In turn, it is able to confirm that by making voidage make for 33% or more and 55% or less Impact absorbing index is higher than 100%, excellent impact resistance.

In addition, according to Figure 15 as a result, it is possible to confirm the rushing relative to central area area in each experimental example It hits absorption index to be also distributed about on curve of approximation, in central area, area is 0.35mm²Left and right obtains peak value.

In such manner, it is possible to find out between central area area and impact absorbing index there is also related, therefore it is able to confirm that To the case where improving impact resistance by selecting central area area.In turn, according to containing the radical of bare wire be 5 realities The evaluation result for testing the steel cord of 17~experimental example of example 26 is able to confirm that by making central area area be 0.24mm²More than And 0.45mm²Make impact absorbing index higher than 100% below, excellent impact resistance.

In addition, by 1~experimental example of experimental example 26, also it is able to confirm that in initial elongation degree, is considered in the past to resistance to punching There is no correlation between the breaking load that hitting property is affected and impact absorbing index.

Claims

1. a kind of steel cord, which is characterized in that

The steel cord has 1 × n structures for being twisted n root bare wires, wherein n=3 or 4,

In the section vertical with length direction,

When the area of maximum circumcircle is set as S1 and the area of bare wire is set as S2, by the gap of formula below (A) expression Rate V be 37% or more and 60% hereinafter,

V (%)=(S1-nS2)/S1 × 100 ... (A).

2. a kind of steel cord, which is characterized in that

The steel cord has 1 × n structures for being twisted n root bare wires, wherein n=5,

In the section vertical with length direction,

When the area of maximum circumcircle is set as S1 and the area of bare wire is set as S2, by the gap of formula below (A) expression Rate V be 33% or more and 55% hereinafter,

V (%)=(S1-nS2)/S1 × 100 ... (A).

3. steel cord according to claim 1, which is characterized in that

The steel cord has 1 × 3 structure for being twisted 3 bare wires,

In the section vertical with length direction,

By the area for surrounding the straight line linked between the center of the adjacent bare wire of circumferencial direction of the maximum circumcircle The area in domain is 0.07mm²Above and 0.13mm²Below.

4. steel cord according to claim 1 or 3, which is characterized in that

The steel cord has 1 × 3 structure for being twisted 3 bare wires,

Charpy is indicated when using the charp impact value of the steel cord of the voidage V 1 × 3 structures for being 35.8% as a reference value Impact value is more than 100% relative to the impact absorbing index of the ratio of a reference value and is 110% or less.

5. steel cord according to claim 1, which is characterized in that

The steel cord has 1 × 4 structure for being twisted 4 bare wires,

In the section vertical with length direction,

By the area for surrounding the straight line linked between the center of the adjacent bare wire of circumferencial direction of the maximum circumcircle The area in domain is 0.16mm²Above and 0.32mm²Below.

6. steel cord according to claim 1 or 5, which is characterized in that

The steel cord has 1 × 4 structure for being twisted 4 bare wires,

Charpy is indicated when using the charp impact value of the steel cord of the voidage V 1 × 4 structures for being 36.4% as a reference value Impact value is more than 100% relative to the impact absorbing index of the ratio of a reference value and is 140% or less.

7. steel cord according to claim 2, which is characterized in that

The steel cord has 1 × 5 structure for being twisted 5 bare wires,

In the section vertical with length direction,

By the area for surrounding the straight line linked between the center of the adjacent bare wire of circumferencial direction of the maximum circumcircle The area in domain is 0.24mm²Above and 0.45mm²Below.

8. the steel cord according to claim 2 or 7, which is characterized in that

The steel cord has 1 × 5 structure for being twisted 5 bare wires,

Charpy is indicated when using the charp impact value of the steel cord of the voidage V 1 × 5 structures for being 32.0% as a reference value Impact value is more than 100% relative to the impact absorbing index of the ratio of a reference value and is 115% or less.

9. the steel cord according to any one of claim 1~8, which is characterized in that

At least 1 bare wire in bare wire described in n roots repeats have bending part and non-bending part along its length.

10. the steel cord according to any one of claim 1~8, which is characterized in that

Bare wire described in n roots all repeats have bending part and non-bending part along its length.

11. steel cord according to claim 9 or 10, which is characterized in that

By the bare wire place in the plane when from the plane to the bending part of the side away from the plane farther out Until height be defined as kink height in the case of,

The kink height is 0.10mm or more and 0.30mm or less.

12. the steel cord according to any one of claim 9~11, which is characterized in that

Repetition interval between the bending part and the non-bending part is 5.0mm or more and 30.0mm or less.

13. the steel cord according to any one of claim 1~12, which is characterized in that

Initial elongation degree when being applied with 49N is 0.06% or more and 0.35% or less.

14. the steel cord according to any one of claim 1~13, which is characterized in that

The a diameter of 0.22mm or more and 0.42mm or less of the bare wire.

15. the steel cord described in any one of a kind of tire, including claim 1~14.