Golf ball
A golf ball can include a core, amid layer, and a cover. In the golf ball, a hardness Ho at a central point of the core, a core surface hardness Hs, a hardness H1 at a point to which a distance from the central point of the core can be equal to 25% of a radius of the core, a hardness H2 at a point to which a distance from the central point of the core can be equal to 75% of the radius of the core, a hardness Hm of the mid layer, and a hardness Hc of the cover can satisfy all of the following relational expressions. Ho ≤ H 1 ≤ H 2 ≤ Hs ( 1 ) Ho < Hs ( 2 ) ( Hs - Ho ) * ( 3 / 2 ) ≤ ( Hm - Hc ) ( 3 ) ( Hs - Hc ) * ( 3 / 2 ) ≤ ( Hm - Hs ) . ( 4 )
1 . A golf ball comprising:
a spherical core,
a mid layer positioned outside the core, and
a cover positioned outside the mid layer,
wherein the golf ball satisfies the following relational expressions (1) to (4):
Ho
≤
H
1
≤
H
2
≤
Hs
,
(
1
)
Ho
<
Hs
,
(
2
)
(
Hs
-
Ho
)
*
(
3
/
2
)
≤
(
Hm
-
Hc
)
,
and
(
3
)
(
Hs
-
Hc
)
*
(
3
/
2
)
≤
(
Hm
-
Hs
)
,
(
4
)
wherein
Ho: Shore-C hardness at a central point of the core,
Hs: Shore-C hardness at a surface of the core,
H1: Shore-C hardness at a point to which a distance from the central point of the core is equal to 25% of a radius of the core,
H2: Shore-C hardness at a point to which a distance from the central point of the core is equal to 75% of the radius of the core,
Hm: Shore-C hardness of the mid layer,
Hc: Shore-C hardness of the cover,
wherein the golf ball further satisfies the following relational expression (7):
(
Hm
-
H
2
)
>
¯
23
,
(
7
)
and
wherein a compressive deformation Dc of the core is 3.80-5.00 mm.
2 . The golf ball according to claim 1 , further satisfying the following relational expression (5):
Hc
<
¯
Hs
.
(
5
)
3 . The golf ball according to claim 1 , further satisfying the following relational expression (6):
Ho
<
¯
Hc
.
(
6
)
4 . The golf ball according to claim 1 , further satisfying the following relational expression (8):
(
Hm
-
H
1
)
<
¯
3
6
.
(
8
)
5 . The golf ball according to claim 1 , wherein
a material of the mid layer is a resin composition, and
a base polymer of the resin composition is an ionomer resin.
6 . The golf ball according to claim 1 , wherein
a material of the cover is a resin composition, and
a base polymer of the resin composition is an ionomer resin.
7 . The golf ball according to claim 1 , wherein the mid layer directly contacts the core and the cover.
8 . The golf ball according to claim 1 , wherein a compressive deformation Db of the golf ball is 3.00 mm-3.40 mm.
9 . The golf ball according to claim 1 , wherein a difference between Hm and H2 is 23 to 30.
10 . A golf ball comprising:
a spherical core,
a mid layer positioned outside the core, and
a cover positioned outside the mid layer,
wherein the golf ball satisfies the following relational expressions (1) to (4):
Ho
≤
H
1
≤
H
2
≤
Hs
,
(
1
)
Ho
<
Hs
,
(
2
)
(
Hs
-
Ho
)
*
(
3
/
2
)
≤
(
Hm
-
Hc
)
,
and
(
3
)
(
Hs
-
Hc
)
*
(
3
/
2
)
≤
(
Hm
-
Hs
)
,
(
4
)
wherein
Ho: Shore-C hardness at a central point of the core,
Hs: Shore-C hardness at a surface of the core,
H1: Shore-C hardness at a point to which a distance from the central point of the core is equal to 25% of a radius of the core,
H2: Shore-C hardness at a point to which a distance from the central point of the core is equal to 75% of the radius of the core,
Hm: Shore-C hardness of the mid layer, and
Hc: Shore-C hardness of the cover, and
wherein
a difference between Hm and H2 is 25 to 27, and
a compressive deformation Dc of the core is 3.80-5.00 mm.
11 . The golf ball according to claim 10 , wherein the mid layer directly contacts the core and the cover.
12 . The golf ball according to claim 10 , wherein a compressive deformation Db of the golf ball is 3.00 mm-3.40 mm.
13 . A golf ball comprising:
a spherical core,
a mid layer positioned outside the core, and
a cover positioned outside the mid layer,
wherein the golf ball satisfies the following relational expressions (1) to (4):
Ho
≤
H
1
≤
H
2
≤
Hs
,
(
1
)
Ho
<
Hs
,
(
2
)
(
Hs
-
Ho
)
*
(
3
/
2
)
≤
(
Hm
-
Hc
)
,
and
(
3
)
(
Hs
-
Hc
)
*
(
3
/
2
)
≤
(
Hm
-
Hs
)
,
(
4
)
wherein
Ho: Shore-C hardness at a central point of the core,
Hs: Shore-C hardness at a surface of the core,
H1: Shore-C hardness at a point to which a distance from the central point of the core is equal to 25% of a radius of the core,
H2: Shore-C hardness at a point to which a distance from the central point of the core is equal to 75% of the radius of the core,
Hm: Shore-C hardness of the mid layer, and
Hc: Shore-C hardness of the cover, and
wherein the golf ball satisfies the following relational expressions (5) to (8):
Hc
≤
Hs
,
(
5
)
Ho
≤
Hc
,
(
6
)
(
Hm
-
H
2
)
≥
23
,
and
(
7
)
(
Hm
-
H
1
)
≤
36
,
(
8
)
and
wherein
a difference between Hm and H2 is 23 to 30,
a compressive deformation Dc of the core is 3.80-5.00 mm, and
a compressive deformation Db of the golf ball is 3.00 mm-3.40 mm.
14 . The golf ball according to claim 13 , wherein the mid layer directly contacts the core and the cover.
15 . The golf ball according to claim 13 , wherein the difference between Hm and H2 is 25 to 27.