Golf ball

1. A golf ball comprising a core, a mid layer positioned outside the core, and a cover positioned outside the mid layer, wherein

the mid layer includes a first mid layer, a second mid layer positioned outside the first mid layer, and a third mid layer positioned outside the second mid layer, and

when: a volume (mm 3 ) of the first mid layer is defined as Vinm;

a Shore D hardness of the first mid layer is defined as Hinm;

a volume (mm 3 ) of the second mid layer is defined as Vm;

a Shore D hardness of the second mid layer is defined as Hm;

a volume (mm 3 ) of the third mid layer is defined as Voum;

a Shore D hardness of the third mid layer is defined as Houm;

a volume (mm 3 ) of the cover is defined as Vc;

a Shore D hardness of the cover is defined as Hc; and

a volume of an entirety of the golf ball is defined as V,

the golf ball meets the following relational expressions (a) to (f):

Hinm<Hm>Houm>Hc,   (a)

Vinm<Vm>Voum>Vc,   (b)

Hm−Hc> 25,  (c)

( Vinm+Vm+Voum+Vc )/ V≦ 0.38,  (d)

Vm/Vc> 1.50, and  (e)

( Vm*Hm )/( Vc*Hc )>3.0;  (f)

wherein the Shore D hardness Hc of the cover is equal to or greater than 10 but equal to or less than 29,

the volume Voum of the third mid layer is greater than the volume Vinm of the first mid layer,

the volume Vinm of the first mid layer is equal to or greater than 2700 mm 3 but equal to or less than 4600 mm 3 ,

the volume Vm of the second mid layer is equal to or greater than 3900 mm 3 but equal to or less than 5400 mm 3 ,

the volume Voum of the third mid layer is equal to or greater than 3500 mm 3 but equal to or less than 4500 mm 3 , and

the volume Vc of the cover is equal to or greater than 1500 mm 3 but equal to or less than 3200 mm 3 .

2. The golf ball according to claim 1 , wherein the golf ball meets the following relational expression (g):

Vc/V< 0.08.  (g)

3. The golf ball according to claim 1 , wherein

the second mid layer is formed from a resin composition, and

a principal component of a base resin of the resin composition is selected from an ionomer resin, a polyamide resin, and a mixture thereof.

4. The golf ball according to claim 1 , wherein the hardness Hm is equal to or greater than 68.

5. The golf ball according to claim 1 , wherein

a JIS-C hardness Hs at a surface of the core is greater than a JIS-C hardness Ho at a central point of the core, and

a difference (Hs−Ho) between the hardness Hs and the hardness Ho is equal to or greater than 28.

6. The golf ball according to claim 1 , wherein the hardness Hinm is less than the hardness Houm.

7. The golf ball according to claim 1 , wherein

the core is obtained by a rubber composition being crosslinked, and

the rubber composition includes:

a co-crosslinking agent; and

(A) a carboxylic acid and/or a salt thereof which can react with the co-crosslinking agent;

wherein the co-crosslinking agent is an α,β-unsaturated carboxylic acid having 2 to 8 carbon atoms, and/or a metal salt of an α,β-unsaturated carboxylic acid having 2 to 8 carbon atoms.

8. The golf ball according to claim 7 , wherein the (A) carboxylic acid and/or salt thereof is an aromatic carboxylic acid and/or a salt thereof; or the (A) carboxylic acid and/or the salt thereof is a fatty acid and/or a salt thereof which excludes stearic acid and zinc stearate.

9. The golf ball according to claim 1 , wherein a JIS-C hardness Hs at a surface of the core is equal to or greater than 84 but equal to or less than 96; and the Shore D hardness Hinm of the first mid layer is equal to or greater than 40 but equal to or less than 55.

10. A golf ball comprising a core, a mid layer positioned outside the core, and a cover positioned outside the mid layer,

wherein the mid layer includes a first mid layer, a second mid layer positioned outside the first mid layer, and a third mid layer positioned outside the second mid layer,

wherein when:

a volume (mm 3 ) of the first mid layer is defined as Vinm;

a Shore D hardness of the first mid layer is defined as Hinm;

a volume (mm 3 ) of the second mid layer is defined as Vm;

a Shore D hardness of the second mid layer is defined as Hm;

a volume (mm 3 ) of the third mid layer is defined as Voum;

a Shore D hardness of the third mid layer is defined as Houm;

a volume (mm 3 ) of the cover is defined as Vc;

a Shore D hardness of the cover is defined as Hc; and

a volume of an entirety of the golf ball is defined as V,

the golf ball meets the following relational expressions (a) to (f):

Hinm<Hm>Houm>Hc,   (a)

Vinm<Vm>Voum>Vc,   (b)

Hm−Hc> 25,  (c)

Vinm+Vm+Voum+Vc )/ V≦ 0.38,  (d)

Vm/Vc> 1.50, and  (e)

( Vm*Hm )/( Vc*Hc )>3.0;  (f)

wherein the core is obtained by a rubber composition being crosslinked and the rubber composition of the core does not include esters of an aromatic carboxylic acid; and

wherein the rubber composition comprises: a co-crosslinking agent and (A) a carboxylic acid and/or a salt thereof which can react with the co-crosslinking agent;

wherein the co-crosslinking agent is an α,β-unsaturated carboxylic acid having 2 to 8 carbon atoms; and/or a metal salt of an α,β-unsaturated carboxylic acid having 2 to 8 carbon atoms; and

wherein the carboxylic acid and/or the salt thereof (A) is an aromatic carboxylic acid and/or a salt thereof.

11. The golf ball according to claim 1 , wherein

a thickness Tinm of the first mid layer is equal to or greater than 0.5 mm but equal to or less than 1.2 mm.

12. The golf ball according to claim 1 , wherein

a thickness Tm of the second mid layer is equal to or greater than 0.8 mm but equal to or less than 1.4 mm.

13. The golf ball according to claim 1 , wherein

a thickness Toum of the third mid layer is equal to or greater than 0.5 mm but equal to or less than 1.2 mm.

14. The golf ball according to claim 1 , wherein

a thickness Tc of the cover is equal to or greater than 0.1 mm but equal to or less than 0.6 mm.

15. The golf ball according to claim 1 , wherein

the core has a diameter of 36.0 mm or greater but 42.0 mm or less.

16. The golf ball according to claim 1 , wherein

the mid layer has an outer diameter of 40.9 mm or greater but 42.1 mm or less.