JP6795776B1 - Golf club head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf club head which is advantageous in obtaining a comfortable hitting sound while improving the moment of inertia. When the cover body 46 is located within the first range A1, it is advantageous in securing the moment of inertia MI. This is because the cover body 46 having a light specific gravity is located near the center of gravity G0, and the head body 12 having a heavy specific gravity is located far from the center of gravity G0. The rib 40 is formed so as to extend in the toe heel direction so as to cross the opening 32 at a substantially central position of the second range A2. Since the cover body 46 is reinforced by the ribs 40 and the strength and rigidity of the cover body 46 are increased, the hitting sound tends to be high, which is advantageous in obtaining a comfortable hitting sound. [Selection diagram] Fig. 4

Description

The present invention relates to a golf club head.

Improving the directionality of the ball when hit with the golf club head is advantageous in improving the flight distance, and for that purpose, it is necessary to secure the moment of inertia around the center of gravity of the golf club head. is important.
Patent Document 1 proposes a golf club head in which openings are provided in a crown portion and a side portion of a hollow metal head body, and the openings are closed with a cover body made of fiber reinforced resin.
In this golf club head, a cover body having a small specific gravity is placed near the center of gravity of the golf club head, and a metal head body having a large specific gravity is placed away from the center of gravity to provide a moment of inertia. Is being improved.

Japanese Patent No. 5952655

However, in the above-mentioned conventional technique, since the cover body uses a fiber reinforced resin having a rigidity and elastic modulus smaller than those of the metal material, it is generated at the time of hitting the ball as compared with the case where the golf club head is made of only the metal material. The hitting sound becomes a low tone, which is disadvantageous in obtaining a comfortable hitting sound.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a golf club head which is advantageous in obtaining a comfortable hitting sound while improving the moment of inertia.

In order to achieve the above object, the present invention presents the present invention from a face portion having a vertical height and extending to the left and right, a crown portion extending rearward from the upper portion of the face portion, and a lower portion of the face portion. A sole portion extending rearward and a side portion extending between the crown portion and the sole portion and between the toe side edge and the heel side edge of the face portion through the face back are formed of a metal material. From a hollow head body whose inside is a space, and a fiber-reinforced resin material that closes openings formed at at least one of the crown portion, the side portion, and the sole portion from the outside of the head body. A hollow golf club head including a cover body, which passes through the center point of the face surface in a reference state in which the golf club head is installed according to a predetermined lie angle and loft angle with respect to a horizontal plane. The cross section of the head body cut along the plane including the normal line and orthogonal to the horizontal plane is defined as the face center reference cross section, and the plane perpendicular to the horizontal plane and the face center reference cross section and abutting the leading edge in the reference state is the first. When one plane is used and the plane parallel to the first plane and abutting on the outer surface of the face back is the second plane, the distance between the first plane and the second plane is the maximum head width M, and the first plane is defined as the first plane. The first plane and the plane parallel to the second plane are set as the central plane at a position halved in the dimension connecting the plane and the second plane, and the head maximum width M is from the central plane to the face portion side. A plane parallel to the central surface at a position separated by 1/4 is set as a third plane, and a plane parallel to the central surface is provided on the face back side from the central surface at a position separated by 1/4 of the maximum head width M. When the fourth plane is used, the cover body is located within the first range partitioned by the third plane and the fourth plane, parallel to the central surface, and the edge of the cover body closest to the face portion. When the plane passing through the portion is the fifth plane and the plane parallel to the center plane and passing through the edge of the cover body closest to the face back is the sixth plane, the fifth plane and the sixth plane are A rib made of a metal material that supports an inner surface portion of the cover body facing the space through the opening at a substantially central position of the partitioned second range from the space side provides the opening. It is formed so as to extend in the toe heel direction so as to cross the head body, the rib is provided integrally with the head body, and the metal material of the rib is the same as the metal material of the head body. The bu extends in the toe heel direction and both ends in the extending direction are connected to the edge of the opening, and the rib has a T-shaped cross section and includes a support wall portion and a reinforcing wall portion. The support wall portion is superposed on the inner surface of the cover body whose cover body faces the space, and the reinforcing wall portion is the support wall at the center in the width direction orthogonal to the extending direction of the support wall portion. The portion is characterized in that the portion projects from the inner surface of the support wall portion facing the space toward the space side over the entire length of the support wall portion .
Further, the present invention is characterized in that the dimension of the portion where the rib supports the cover body in the toe heel direction is substantially the same as the total length of the dimension of the cover body in the toe heel direction.
Further, in the present invention, the rib is formed so as to extend continuously from the inner surface of the cover body to the inner surface of the head body whose head body faces the space, and the rib is formed on the inner surface of the cover body. The golf club head is formed so as to extend over 80% or more of the entire circumference of the inner surface of the golf club head including the inner surface of the head body.
Further, in the present invention, in the head body, a boundary portion extending in a band shape over the entire length of the boundary between the crown portion and the side portion is formed, and the boundary portion is made of a metal material constituting the head body. It is characterized in that it is formed.
Further, in the present invention, the portion within the first range of the boundary portion is formed with a wall thickness larger than the wall thickness of the crown portion and the side portion adjacent to the boundary portion. It is characterized by being composed of parts.
Further, in the present invention, the head mass of the golf club head is 210 g or less, and the magnitude of the moment of inertia having a vertical straight line passing through the center of gravity of the golf club head and orthogonal to the horizontal plane in the reference state as the rotation axis is large. When the value is MI (g · cm ² ), the moment of inertia MI is 6200 g · cm ² or less.
Further, the present invention is characterized in that the head volume of the golf club head is 500 cc or less, and the maximum head width M is 130 mm or less.
Further, according to the present invention, the head body is located in a portion of the head body located in a third range partitioned by the first plane and the third plane, and in a fourth range from the fourth plane to the face back. It is characterized in that a large specific gravity portion formed of a material having a specific gravity larger than that of the portion located in the first range is provided on at least one portion of the portion.
Further, the present invention has a face portion having a vertical height and extending to the left and right, a crown portion extending rearward from the upper part of the face portion, and a sole extending rearward from the lower portion of the face portion. The portion and the side portion extending between the crown portion and the sole portion and between the toe side edge and the heel side edge of the face portion through the face back are formed of a metal material, and the inside thereof is a space. A hollow head body to be formed, and a cover body made of a fiber-reinforced resin material that closes openings formed at at least one of the crown portion, the side portion, and the sole portion from the outside of the head body. A hollow golf club head including a normal line passing through a center point of a face surface in a reference state in which the golf club head is installed according to a predetermined lie angle and loft angle with respect to a horizontal plane. The cross section obtained by breaking the head body in a plane orthogonal to the horizontal plane is defined as the face center reference cross section, and in the reference state, the plane perpendicular to the horizontal plane and the face center reference cross section and abutting on the leading edge is defined as the first plane. When the plane parallel to the one plane and abutting on the outer surface of the face back is the second plane, the distance between the first plane and the second plane is the maximum head width M, and the first plane and the second plane are The first plane and the plane parallel to the second plane are set as the central plane at the position of 1/2 of the dimension connecting the two, and the position separated from the central plane to the face portion side by 1/4 of the maximum width M of the head. When the plane parallel to the central plane is the third plane and the plane parallel to the central plane at a position separated from the central plane by 1/4 of the maximum width M of the head is the fourth plane. , The cover body is located in the first range partitioned by the third plane and the fourth plane, and the portion of the head body located in the fourth range from the fourth plane to the face back. A large specific gravity portion made of a material having a specific gravity larger than that of the remaining portion excluding the fourth range is provided, and the specific gravity of the portion of the head body located in the fourth range is defined as the rear specific gravity Ga. The specific gravity of the portion of the head body located in the third range divided by the first plane and the third plane is defined as the front specific gravity Gb, and the specific gravity of the portion of the head body located in the first range. The golf club head is characterized in that the following equation (1) is satisfied, where is defined as the intermediate specific gravity Gc.
Ga>Gb> Gc …… (1)

According to the present invention, a cover body having a light specific gravity is arranged near the center of gravity of the golf club head, and a portion of the head body made of a metal material having a heavier specific gravity than the cover body is located far from the center of gravity. By arranging the golf club head in, the moment of inertia MI of the golf club head can be secured, which is advantageous in improving the directionality of the hit ball.
Further, the cover body is reinforced by supporting the cover body with ribs having higher rigidity than the cover body, whereby the same effect as increasing the rigidity and elastic modulus of the cover body can be exhibited.
Therefore, despite the structure in which the opening is closed with a cover body having a lower rigidity and elastic modulus than the head body made of a metal material, the hitting sound generated at the time of hitting can be made high-pitched, and a comfortable hitting sound can be produced. It will be advantageous to obtain.
Further, according to the present invention, a cover body having a light specific gravity is arranged near the center of gravity of the golf club head, and a large specific gravity portion made of a material having a heavier specific gravity than the cover body is located far from the center of gravity. By arranging the golf club head in, the moment of inertia MI of the golf club head can be secured, which is advantageous in improving the directionality of the hit ball.
Furthermore, since the large specific gravity part is provided at the position closest to the face back, which is the starting point of vibration at the time of hitting the ball, the vibration generated at the time of hitting the ball passes through the part of the head body to the large specific gravity part which is a heavy object. In the process of transmission, the same action as the so-called mass damper function occurs, the vibration is attenuated, and the lower frequency vibration component of the vibration is more likely to be attenuated, so that the bass component of the hitting sound is attenuated. On the other hand, the treble component is not so attenuated.
Therefore, despite the structure in which the opening is closed with a cover body having a lower rigidity and elastic modulus than the head body made of a metal material, the hitting sound generated at the time of hitting can be made high-pitched, and a comfortable hitting sound can be produced. It will be advantageous to obtain.

It is a front view which looked at the golf club head which concerns on 1st Embodiment from the front of the face surface. It is a view of arrow A of FIG. It is a B arrow view of FIG. FIG. 2 is a cross-sectional view taken along line XX of FIG. It is a top view of the head body which removed the cover body. It is a view of arrow A of FIG. It is a B arrow view of FIG. It is a C arrow view of FIG. 5A and 5B are simplified cross-sectional views taken along the X-ray cross section, where FIG. 5A is a cross-sectional view showing ribs and FIG. It is sectional drawing of an opening and a rib. It is a 1st explanatory view which shows the method of defining the center point Pc of a face surface. It is a 2nd explanatory view which shows the method of defining the center point Pc of a face surface. It is a 3rd explanatory view which shows the method of defining the center point Pc of a face surface. It is a 4th explanatory view which shows the method of defining the center point Pc of a face surface. It is sectional drawing of the golf club head which shows the relationship between the center of gravity point G0 of a golf club head and the center of gravity point FG on a face surface. It is a front view of the golf club head explaining the definition of the contour line I of a face surface. It is sectional drawing of the golf club head explaining the definition of the contour line I of a face surface. It is a front view of the golf club head explaining the definition of the center point Pc of a face surface. It is a schematic perspective view which shows the moment of inertia measuring instrument which measures the moment of inertia of a golf club head. (A) and (B) are schematic views showing the method of measuring the moment of inertia in the order of processes. (A) to (C) are schematic views for explaining the fixing position which fixes a golf club head to a jig at the time of measuring a moment of inertia. It is a schematic diagram for demonstrating the preferable form of the fixing position which fixes a golf club head to a jig at the time of measuring a moment of inertia. It is a figure which shows the evaluation result of the experimental example under condition 1. It is a figure which shows the evaluation result of the experimental example under condition 2. It is a figure which shows the evaluation result of the experimental example under condition 3. It is a figure which shows the evaluation result of the experimental example under condition 4. It is a figure which shows the evaluation result of the experimental example under condition 5. It is a figure which shows the evaluation result of the experimental example under condition 6. It is sectional drawing of the golf club head corresponding to Experimental Example 2. It is sectional drawing of the golf club head corresponding to Experimental Example 3. It is sectional drawing of the golf club head corresponding to Experimental Example 4. It is sectional drawing of the golf club head corresponding to Experimental Example 5. It is sectional drawing of the golf club head corresponding to Experimental Example 6. It is sectional drawing of the golf club head corresponding to Experimental Example 17. It is sectional drawing of the golf club head corresponding to Experimental Example 18. It is sectional drawing of the golf club head corresponding to Experimental Example 19. It is sectional drawing of the golf club head corresponding to Experimental Example 20. (A) A cross-sectional view of a simplified golf club head corresponding to Experimental Examples 8 and 9, and (B) a cross-sectional view of a simplified golf club head corresponding to Experimental Examples 7 and 10, a face center reference cross section Pfc and A cross section orthogonal to the horizontal plane HP is shown. It is the top view of the simplified head body corresponding to Experimental Example 11. It is a top view of the golf club head which shows the modification. It is sectional drawing of the golf club head which concerns on 2nd Embodiment. It is sectional drawing of the golf club head which concerns on the modification of the 2nd Embodiment. It is a figure which shows the evaluation result of the experimental example of the golf club head which concerns on 2nd Embodiment.

(First Embodiment)
Next, an embodiment of the present invention will be described.
As shown in FIGS. 1 to 8, in the present embodiment, the golf club head 10 is a hollow wood type golf club head (driver), and includes a head body 12 and a cover body 46 (FIG. 2). ing. In FIG. 3, the cover body 46 is not shown.

The head body 12 is made of a metal material.
As the metal material, for example, one kind or two or more kinds such as stainless steel, maraging steel, pure titanium, titanium alloy or aluminum alloy are used.
The head body 12 includes a face portion 14, a crown portion 16, a sole portion 18, and a side portion 20.
The face portion 14 has a vertical height and extends to the left and right.
The crown portion 16 extends rearward from the upper portion of the face portion 14.
The sole portion 18 extends rearward from the lower portion of the face portion 14.
The side portion 20 extends between the crown portion 16 and the sole portion 18 through the face back 28 between the toe 22 side edge of the face portion 14 and the heel 24 side edge.
As shown in FIG. 4, the head body 12 has a hollow shape (hollow structure) with a space 13 inside surrounded by the face portion 14, the crown portion 16, the sole portion 18, and the side portion 20.
The outer surface exposed to the outside of the face portion 14 is the face surface 14A for hitting the ball, and the inner surface of the face portion 14 facing the space 13 is the face inner surface 14B.
The outer surface exposed to the outside of the crown portion 16 is the crown surface 16A, and the inner surface of the crown portion 16 facing the space 13 is the crown inner surface 16B.
The outer surface exposed to the outside of the sole portion 18 is the sole surface 18A, and the inner surface of the sole portion 18 facing the space 13 is the sole inner surface 18B.
The outer surface exposed to the outside of the side portion 20 is the side surface 20A, and the inner surface of the side portion 20 facing the space 13 is the side inner surface 20B.
In the following, the crown surface 16A, the sole surface 18A, and the side surface 20A are collectively referred to as the outer surface of the head body 12, and the crown inner surface 16B, the sole inner surface 18B, and the side inner surface 20B are collectively referred to as the inner surface of the head body 12.
In the figure, reference numeral 26 indicates a leading edge.

As shown in FIGS. 1 to 3, the crown portion 16 is provided with a hosel 29 connected to the shaft S on the face surface 14A side and at a position closer to the heel 24, and the shaft S is connected to the hosel 29. A golf club is composed.

As shown in FIGS. 5 to 7, in the head main body 12, band-shaped boundary portions 30 are provided at the boundaries between the crown portion 16 and the side portions 20 on the toe 22 side and the heel 24 side, respectively, and two of them are provided. The boundary portion 30 is formed of a metal material constituting the head main body 12.
The boundary portion 30 is provided at a position displaced inside the head main body 12 by the thickness Tc of the cover body 46 from the outer surface of the head main body 12.

As shown in FIGS. 4 to 8, openings 32 are formed in at least one of the crown portion 16, the side portion 20, and the sole portion 18 in the head main body 12.
In the present embodiment, the first opening 32A is formed in the crown portion 16, the second opening 32B is formed from the side portion 20 on the toe 22 side to the sole portion 18 on the toe 22 side, and the side portion on the heel 24 side. A third opening 32C is formed from 20 to the sole portion 18 on the heel 24 side.
That is, the first opening 32A and the second opening 32B are separated by the boundary portion 30 on the toe 22 side, and the first opening 32A and the third opening 32C are separated by the boundary portion 30 on the heel 24 side. There is.
Then, each of the openings 32A to 32C is closed by two cover bodies 46 described later.
As shown in FIGS. 4 to 8, a mounting portion 34 for mounting the cover body 46 described later is formed along the edges of the openings 32A to 32C.
As shown in FIGS. 5 and 10, the mounting portion 34 includes a vertical plate portion 36, a horizontal plate portion 38, and a boundary portion 30, and is formed in a concave shape recessed inside the head main body 12.
The vertical plate portion 36 projects from the outer surface of the head body 12 to the inside of the head body 12 by the thickness Tc of the cover body 46.
The horizontal plate portion 38 is connected to the tip of the vertical plate portion 36, and therefore, the openings 32A to 32C are displaced from the outer surface of the head main body 12 to the inside of the head main body 12 by the thickness Tc of the cover body 46. It extends along the edges of the face portion 14 side and the face back 28 side.
The boundary portion 30 connects the horizontal plate portion 38 on the face portion 14 side and the toe 22 side on the toe 22 side and the heel 24 side.
Therefore, in a state where the cover body 46 is fitted inside the vertical plate portion 36 and closes the openings 32A to 32C, a step between the outer surface of the cover body 46 where the cover body 46 is exposed to the outside and the outer surface of the head body 12 Is designed not to occur.

As shown in FIGS. 4 to 8 and 10, ribs made of a metal material that support the inner surface portion of the cover body 46 facing the space 13 through the openings 32A to 32C from the space 13 side. 40 is formed so as to extend in the toe heel direction so as to cross each of the openings 32A to 32C.
The length of the rib 40 is defined as described later, but in the example shown in FIG. 9A, the rib 40 is formed over the entire circumference of the inner surface of the head body 12.
More specifically, as shown in FIGS. 5 to 8, the ribs 40 include a first rib portion 40A that crosses the first opening 32A, a second rib portion 40B that crosses the second opening 32B, and a third rib portion 40B. A third rib portion 40C that crosses the opening portion 32C, a fourth rib portion 40D extending along the inner surface of the sole portion 18, and a fifth rib portion provided at a boundary portion 30 on the toe 22 side and the heel 24 side. It is configured to include the part 40E.
Further, in the present embodiment, the first rib portion 40A, the second rib portion 40B, the third rib portion 40C, the fourth rib portion 40D, and the fifth rib portion 40E are the same as the metal materials constituting the head body 12. It is made of metal material.

As shown in FIG. 10, the rib 40 has a T-shaped cross section, and includes a support wall portion 42 and a reinforcing wall portion 44.
In the first to third rib portions 40A to 40C, the support wall portion 42 is a portion where the cover body 46 is overlapped with the inner surface of the cover body 46 facing the space 13 and has a strip shape. Further, the support wall portion 42 is a portion of the fourth rib portion 40D that is joined to the sole inner surface 18B of the sole portion 18 and has a strip-like shape. Further, the support wall portion 42 is formed at the boundary portion 30 in the fifth rib portion 40E.
The outer surface of the support wall portion 42 superimposed on the inner surface of the cover body 46 is provided at a position displaced inside the head main body 12 by the thickness Tc of the cover body 46 rather than the outer surface of the head main body 12.
Therefore, at the intersection of the first rib portion 40A and the boundary portion 30, the outer surface of the support wall portion 42 and the outer surface of the boundary portion 30 are located on the same surface, and the second rib portion 40B and the boundary portion 30 are aligned. At the intersection, the outer surface of the support wall portion 42 and the outer surface of the boundary portion 30 are located on the same surface, and at the intersection of the third rib portion 40C and the boundary portion 30, the outer surface of the support wall portion 42 and the boundary portion are bordered. The outer surface of the portion 30 is located on the same surface.
Further, at the intersection of the boundary portion 30 and the horizontal plate portion 38, the outer surface of the support wall portion 42 and the outer surface of the horizontal plate portion 38 are located on the same surface.
The reinforcing wall portion 44 is located in the center in the width direction orthogonal to the extending direction of the support wall portion 42, from the inner surface of the support wall portion 42 facing the space 13 to the space 13 side over the entire length of the support wall portion 42. It is protruding.

In the present embodiment, the dimensions of the rib 40 are as follows.
The height H of the rib 40 is 2 mm or more and 10 mm or less.
Here, the height H of the rib 40 is the dimension from the surface of the support wall portion 42 overlapped with the inner surface of the cover body 46 and the inner surface of the sole portion 18 to the tip of the reinforcing wall portion 44, and the height H of the boundary portion 30. It is a dimension from the outer surface to the tip of the reinforcing wall portion 44.
The thickness D of the support wall portion 42 and the reinforcing wall portion 44 is 0.5 mm or more and 3 mm or less.
Further, the width W of the rib 40, that is, the width W of the support wall portion 42 is 2 mm or more and 10 mm or less.
When the height H, the thickness D, and the width W are below the lower limit values, the rib 40 reduces the effect of increasing the strength and rigidity of the cover body 46 and the head body 12, which will be described later, and reduces the effect of making the hitting sound high.
Further, when the height H, the thickness D, and the width W each exceed the upper limit values, the weight of the rib 40 becomes too heavy, and the effect of reducing the weight of the head body 12 decreases.

The cover body 46 closes the first to third openings 32A to 32C from the outside of the head body 12, and is made of a fiber-reinforced resin material. As the fiber reinforced resin material, various conventionally known fiber reinforced resin materials such as carbon fiber reinforced resin which is lightweight and has excellent strength can be used.
Further, the material of the cover body 46 may be lighter than the specific gravity of the main body 12, and if it is a metal, a magnesium alloy, an aluminum alloy, a titanium alloy, or the like can be used.
In the case of a fiber-reinforced resin material, since the fiber-reinforced resin has anisotropy in which the strength differs in the fiber direction and the fiber orthogonal direction, the strength is as strong as possible by laminating a plurality of layers having different fiber directions. Is configured to be close to isotropic, and the strength and rigidity of the cover body 46 are improved.
The cover body 46 is generally formed with a uniform wall thickness, but may have an unbalanced wall thickness.
The cover body 46 is formed in a shape continuous with the outer surface of the head main body 12 in a state where the first to third openings 32A to 32C are closed. The outer surface of the club head 10 is configured.

In the present embodiment, the cover body 46 has a toe side cover body 46A that closes the toe 22 side half of the first opening 32A, the second opening 32B, and a heel 24 side of the first opening 32A. It is composed of two cover bodies 46, a half portion of the cover body 46B and a heel side cover body 46B that closes the third opening 32C.
As shown in FIG. 2, on the crown portion 16 side of the head main body 12, the toe side cover body 46A and the heel side cover body 46B are covered joints extending along the direction connecting the face portion 14 and the face back 28. It is joined via a portion 47.
It goes without saying that the toe side cover body 46A and the heel side cover body 46B may be integrally configured.
The inner surface of the cover body 46 is overlapped with the outer surface of the horizontal plate portion 38 of the mounting portion 34, the outer surface of the boundary portion 30, and the outer surface of the support wall portion 42 of the rib 40 from the outside of the head body 12, and the cover body 46 is a vertical plate. In a state where the openings 32A to 32C are closed by being fitted inside the portion 36, the openings 32A to 32C are attached to the attachment portion 34 and the support wall portion 42 of each rib 40 by a conventionally known bonding method such as adhesion or caulking (integrally coupled). The golf club head 10 is assembled by this. Then, the outer surface of the head body 12 and the outer surface of the cover body 46 are appropriately painted to enhance the design.

Next, before explaining the definition of each part of the golf club head 10 in detail, a method of defining the center point Pc of the face surface 14A will be described.
The center point Pc of the face surface 14A is the geometric center of the face surface 14A, and various conventionally known methods of defining the center point Pc include the first defining method and the second defining method exemplified below. The method can be adopted.

[A] First method for defining the center point Pc of the face surface 14A:
When the boundary between the face surface 14A and the portion of the other golf club head 10 is clear, in other words, it is a method of defining the center point Pc when the peripheral edge of the face surface 14A is specified by the ridge line. In this case, the face surface 14A is clearly defined.
11 to 14 are explanatory views showing a method of defining the center point Pc of the face surface 14A.

(1) First, as shown in FIG. 11, the golf club head 10 is placed on the horizontal surface HP so that the lie angle and the face angle become specified values. The state of the golf club head 10 at this time is used as the reference state. The set values of the lie angle and the face angle are, for example, the values described in the product catalog.

(2) Next, the temporary center point c0 in the direction connecting the crown portion 16 and the sole portion 18 is obtained.
That is, as shown in FIG. 11, a perpendicular line f0 that intersects the approximate center point of a line parallel to the horizontal plane HP connecting the toe 22 and the heel 24 (hereinafter referred to as a horizontal line) is drawn.
The midpoint between the a0 point where the perpendicular line f0 and the upper edge of the face surface 14A intersect and the b0 point where the perpendicular line f0 and the lower edge of the face surface 14A intersect is defined as a temporary center point c0.

(3) Next, as shown in FIG. 12, a horizontal line g0 passing through the temporary center point c0 is drawn.
(4) Next, as shown in FIG. 13, at the d0 point where the horizontal line g0 and the edge of the face surface 14A on the toe 22 side intersect, and at the e0 point where the horizontal line g0 and the edge of the face surface 14A on the heel 24 side intersect. Let the midpoint be the temporary center point c1.

(5) Next, as shown in FIG. 14, a perpendicular line f1 passing through the temporary center point c1 is drawn, and the perpendicular line f1 and the upper edge of the face surface 14A intersect with the perpendicular line f1 and the lower edge of the face surface 14A. Let the midpoint of the b1 point where the two intersect is the temporary center point c2.
Here, if the temporary center points c1 and c2 match, that point is defined as the center point Pc of the face surface 14A.
If the temporary center points c1 and c2 do not match, the steps (2) to (5) are repeated.
Since the face surface 14A has a curved surface, the length of the horizontal line g0 and the lengths of the perpendicular lines f0 and f1 when finding the midpoint of the horizontal line g0 and the midpoint of the perpendicular lines f0 and f1 are the curved surface of the face surface 14A. Along the length shall be used.
The face center line CL is defined by a straight line that passes through the center point Pc and extends in a direction orthogonal to the toe 22-heel 24 direction.

[B] A second method for defining the center point Pc of the face surface 14A:
Next, the definition of the center point Pc when the peripheral edge of the face surface 14A and the portion of the other golf club head 10 are connected by a curved surface and the face surface 14A cannot be clearly defined will be described.

As shown in FIG. 15, the golf club head 10 is hollow, the reference numeral G0 indicates the center of gravity point of the golf club head 10, and the reference numeral Lp is a straight line connecting the center of gravity point G0 and the center of gravity point FG on the face surface, in other words. The straight line Lp is a perpendicular line (normal line) of the face surface 14A passing through the center of gravity point G0.
That is, the point where the center of gravity point G0 of the golf club head 10 is projected onto the face surface 14A is the center of gravity point FG on the face surface.
Here, as shown in FIG. 16, consider a large number of planes H1, H2, H3, ..., Hn including a straight line Lp connecting the center of gravity point G0 and the center of gravity point FG on the face surface.

As shown in FIG. 17, the radius of curvature r0 of the outer surface of the golf club head 10 is measured in the cross section when the golf club head 10 is broken along the planes H1, H2, H3, ..., Hn.
When measuring the radius of curvature r0, it is treated as if there is no face line, punch mark, etc. on the face surface 14A.
The radius of curvature r0 is continuously measured from the center point Pc of the face surface 14A in the outward direction (upward and downward in FIG. 17).
Then, in the measurement, the portion where the radius of curvature r0 is first or less than a predetermined value is defined as the contour line I representing the peripheral edge of the face surface 14A.
The predetermined value is, for example, 200 mm.
A range surrounded by contour lines I determined based on a number of planes H1, H2, H3, ..., Hn is defined as the face surface 14A, as shown in FIGS. 16 and 17.

Next, as shown in FIG. 18, the golf club head 10 is placed on a horizontal ground (horizontal plane HP) so that the lie angle and the face angle become specified values.
The straight line LT passes through the toe 22 side point PT of the face surface 14A and extends in the vertical direction.
The straight line LH passes through the heel 24 side point PH of the face surface 14A and extends in the vertical direction.
The straight line LC is parallel to the straight line LT and the straight line LH. The distance between the straight line LC and the straight line LT is equal to the distance between the straight line LC and the straight line LH.
Reference numeral Pu indicates an upper point of the face surface 14A, and reference numeral Pd is a lower point of the face surface 14A. The upper point Pu and the lower point Pd are both intersections of the straight line LC and the contour line I.
The center point Pc is defined by the midpoint of the line segment connecting the upper point Pu and the lower point Pd.

(Face center reference cross section Pfc)
Next, the provisions of each part of the golf club head 10 will be described in detail.
First, the face center reference cross section Pfc of the golf club head 10 is defined.
As shown in FIGS. 1 to 3, the golf club head 10 is set in a reference state in which the golf club head 10 is installed according to a predetermined lie angle and loft angle with respect to the horizontal plane HP.
As shown in FIG. 1, a cross section obtained by breaking the head body 12 on a plane X including a normal passing through the center point Pc of the face surface 14A and orthogonal to the horizontal plane HP is defined as a face center reference cross section Pfc. In other words, the face center reference cross section Pfc is a cross section obtained by breaking the head body 12 on a plane X including the face center line CL and orthogonal to the horizontal plane HP in the reference state.

(1st to 6th planes P1 to P6, central surface P0, 1st range A1, 2nd range A2, head maximum width M)
As shown in FIG. 4, in the reference state of the golf club head 10, the plane orthogonal to the horizontal plane HP and the face center reference cross section Pfc and abutting on the leading edge 26 is defined as the first plane P1.
In addition, in FIG. 4, in order to show the cover body 46 located on the sole portion 18 side, the cross section of the portion displaced in the toe heel direction with respect to the face center reference cross section Pfc is shown.
The plane parallel to the first plane P1 and abutting on the outer surface of the face back 28 is referred to as the second plane P2.
When the head body 12 is viewed in a plane, the distance between the first plane P1 and the second plane P2 is defined as the head maximum width M.
The plane parallel to the first plane P1 and the second plane P2 at a position halved in the dimension connecting the first plane P1 and the second plane P2 is defined as the central plane P0.
A plane parallel to the central surface P0 at a position separated from the central surface P0 on the face portion 14 side by 1/4 of the maximum head width M is referred to as a third plane P3.
A plane parallel to the center plane P0 at a position separated from the center plane P0 on the face back 28 side by 1/4 of the maximum head width M is referred to as a fourth plane P4.
The range partitioned by the third plane P3 and the fourth plane P4 is defined as the first range A1.
The plane parallel to the central surface P0 and passing through the edge of the cover body 46 closest to the face portion 14 is defined as the fifth plane P5.
The plane parallel to the central surface P0 and passing through the edge of the cover body 46 closest to the face back 28 is defined as the sixth plane P6.
The range partitioned by the fifth plane P5 and the sixth plane P6 is defined as the second range A2.

In the present embodiment, the cover body 46 is located within the first range A1.
When the cover body 46 is located within the first range A1, it is advantageous in securing the moment of inertia MI of the golf club head 10, which will be described later.
This is because the cover body 46 having a light specific gravity is located near the center of gravity G0, and the head body 12 having a heavy specific gravity is located far from the center of gravity G0.
On the other hand, if the cover body 46 is located outside the first range A1, it is disadvantageous in securing the moment of inertia MI.
This is because the cover body 46 having a light specific gravity is located far from the center of gravity G0, and the head body 12 having a heavy specific gravity is located near the center of gravity G0.
The method of measuring the moment of inertia MI of the golf club head 10 will be described later.

Further, in the present embodiment, the rib 40 is formed so as to extend in the toe heel direction so as to cross the opening 32 at a substantially central position of the second range A2.
By doing so, the cover body 46 is reinforced by the rib 40, and the strength and rigidity of the cover body 46 are increased, so that the hitting sound tends to be high-pitched, which is advantageous in obtaining a comfortable hitting sound.
Further, the substantially central position of the second range A2 is defined as follows.
That is, the dimension of the second range A2 is α, and the plane parallel to the central surface P0 passing through the position α / 4 away from the central position β of the second range A2 in the face portion 14 direction is defined as the seventh plane P7. Assuming that the plane parallel to the central plane P0 passing through the position α / 4 separated from the central position of the range A2 in the face back 28 direction is the eighth plane P8, the fifth plane is divided by the seventh plane P7 and the eighth plane P8. The range A5 is defined as the substantially central position of the second range A2.
In the present embodiment, the case where the positions of the second range A2 on the crown portion 16 side and the position of the second range A2 on the sole portion 18 side match has been described, but the crown portion 16 side and the sole portion 18 side If the positions of the two second ranges A2 do not match, the rib 40 may be formed at a substantially central position (fifth range A5) of at least one of the second ranges A2.

Further, the dimension in the toe heel direction (dimension along the toe heel direction) of the portion where the rib 40 supports the cover body 46 is substantially the same as the total length of the dimension in the toe heel direction (dimension along the toe heel direction) of the cover body 46. Is preferable in order to secure the strength and rigidity of the cover body 46, and is advantageous in making the hitting sound high.
That is, to explain by diverting FIG. 38, as shown in FIG. 38 (A), the dimensions (Lth1 + Lth2 + Lth3) of the portion where the rib 40 supports the cover body 46 are in the toe heel direction of the cover body 46. It is preferably 70% or more of the total length (Lc1) of the dimension.
That is, when the rib 40 provided on the sole portion 18 is divided into a portion that supports the cover body 46 and a portion that does not support the cover body 46, the rib 40 of the portion that does not support the cover body 46 is It is treated separately from the rib 40 of the portion supporting the cover body 46, and is not included in the calculation of the ratio of the rib 40 to the total length of the dimension in the toe heel direction.
As shown in FIG. 38 (B), the dimension in the toe heel direction (Lth1 + Lth2 + Lth3) of the portion where the rib 40 supports the cover body 46 is less than 70% of the total length (Lc1) of the dimension in the toe heel direction of the cover body 46. If there is, the effect of ensuring the strength and rigidity of the cover body 46 is reduced, and the effect of making the hitting sound high is reduced.

Further, the rib 40 is formed so as to extend continuously from the inner surface of the cover body 46 to the inner surface of the head main body 12 in which the head main body 12 faces the space 13 (see FIG. 9A), and the rib 40 is formed in the cover body 46. 80% or more of the entire circumference of the inner surface of the golf club head 10 (in other words, the entire circumference of the inner surface of the golf club head 10 along the extending direction of the rib 40), which is composed of the inner surface of the golf club head 10 and the inner surface of the head body 12. If so, it becomes more advantageous in making the hitting sound high.
This is because the rib 40 enhances the strength and rigidity of both the cover body 46 and the head body 12.
Therefore, if the length of the rib 40 is less than 80% of the entire circumference of the inner surface of the golf club head 10, the effect of ensuring the strength and rigidity of both the cover body 46 and the head body 12 is reduced, and the hitting sound is made high. The effect of playing golf is reduced.
In the actual shape of the golf club head 10, the curvature of the curved surface of the inner surface of the head body 12 is locally increased at the boundary portion 30 between the crown portion 16 and the side portion 20, so that the golf club head 10 is manufactured. It can be difficult to form the rib 40. Therefore, the rib 40 may not be formed over 100% of the entire inner surface of the golf club head 10.

Further, in the head main body 12, a boundary portion 30 extending in a band shape over the entire length of the boundary between the crown portion 16 and the side portion 20 is formed, and the boundary portion 30 is formed of a metal material constituting the head main body 12. There is.
Therefore, the boundary portion 30 is formed so as not to be divided in the middle of the extending direction.
By forming the boundary portion 30 over the entire length of the boundary between the crown portion 16 and the side portion 20 in this way, the strength and rigidity of the head main body 12 are ensured, so that the strength and rigidity of the head main body 12 are enhanced. It is more advantageous for making the hitting sound high.
It is advantageous that the width of the boundary portion 30 is 1 mm or more in order to increase the strength and rigidity of the head body 12, and that the width of the boundary portion 30 is less than 1 mm, the strength and rigidity of the head body 12 are increased. The effect of enhancing is reduced.

Further, as shown in FIG. 9B, the portion of the boundary portion 30 within the first range A1 has a wall thickness larger than the wall thickness of the crown portion 16 and the side portion 20 adjacent to the boundary portion 30. If it is composed of the thick portion 31 formed of the above, it is more advantageous in securing the moment of inertia MI of the golf club head 10 and also in securing the strength and rigidity of the head body 12.
This is because it is advantageous in securing the moment of inertia MI by arranging the portion having the weight as far as possible from the center of gravity point G0.
The thickness of the thick portion 31 may be 1 mm or more, and more preferably 2 mm or more and 5 mm or less.
When the thickness of the thick portion 31 is 2 mm or more and 5 mm or less, the moment of inertia MI of the golf club head 10 is secured while suppressing the weight increase of the golf club head 10, and the strength and rigidity of the head body 12 are secured. It will be more advantageous in doing so.
If the thickness of the thick portion 31 is less than the above range, the above effect is reduced, and if the thickness of the thick portion 31 exceeds the above range, the weight of the golf club head 10 becomes excessive.
Further, the length of the thick portion 31 may be 10 mm or more, and more preferably 20 mm or more and 50 mm or less.
When the length of the thick portion 31 is 20 mm or more and 50 mm or less, the moment of inertia MI of the golf club head 10 is secured while suppressing the weight increase of the golf club head 10, and the strength and rigidity of the head body 12 are secured. It will be more advantageous to do.
If the length of the thick portion 31 is less than the above range, the above effect is reduced, and if the length of the thick portion 31 exceeds the above range, the weight of the golf club head 10 becomes excessive.

The head mass of the golf club head 10 is 210 g or less, and the magnitude of the moment of inertia about the vertical straight line passing through the center of gravity point G0 of the golf club head 10 and orthogonal to the horizontal plane HP in the reference state is MI ( When g · cm ² ), the moment of inertia MI is 6200 g · cm ² or less.
The head mass is preferably in the range of 180 g or more and 205 g or less.
When the head mass is within the above range, it is advantageous in securing the moment of inertia MI and improving the directionality of the hit ball.
When the head mass is less than the above range, the head weight is small, so that the moment of inertia MI is small, and the effect of improving the directionality of the hit ball is reduced.
When the head weight exceeds the above range, the head weight is large, so that the swing speed is lowered and the effect of securing the flight distance is lowered.
In addition, the moment of inertia MI of the golf club head 10, it is preferable that the 5000g · cm ² or more 6000g · cm ² or less.
When the moment of inertia MI is within the above range, it is advantageous in improving the directionality of the hit ball.
When the moment of inertia MI is less than the above range, the effect of improving the directionality of the hit ball is reduced.
In addition, the upper limit of the British R & A Rules of Golf moment of inertia MI defined in is ^{5900g · cm 2 + 100g · cm} 2.

Further, the head volume of the golf club head 10 is 500 cc or less, and the maximum head width M is 130 mm or less.
Further, it is preferable that the head volume is in the range of 440 cc or more and 470 cc or less, and the maximum head width M is in the range of 120 mm or more and 127 mm or less.
When the volume of the head body 12 is within the above range, it is advantageous in securing the moment of inertia MI.
If the volume of the head body 12 is less than the above range, the effect of securing the moment of inertia MI is reduced.
The upper limit of the volume of the head body 12 defined by the R & A Rules of Golf in the United Kingdom is 470 cc.
Further, when the maximum head width value M is within the above range, it is advantageous in securing the moment of inertia MI.
When the maximum head width value M is less than the above range, the effect of securing the moment of inertia MI is reduced.
The upper limit of the head maximum width M defined by the R & A Golf Rules of the United Kingdom is 127 mm.

As shown in FIG. 4, a portion of the head body 12 located in the third range A3 partitioned by the first plane P1 and the third plane P3, and the fourth range from the fourth plane P4 to the face back 28. At least one portion of the portion located in A4 is formed of a (metal) material having a specific gravity larger than the specific gravity of the portion located in the first range A1 partitioned by the third plane P3 and the fourth plane P4. If the large specific gravity portion 48 is provided, the weight of a portion farther away from the center of gravity point G0 can be increased, which is advantageous in securing the moment of inertia MI.
In this case, the portion of the head body 12 excluding the large specific gravity portion 48 and the large specific gravity portion 48 may be made of metal materials having different specific gravities, and various conventionally known metal materials are used as such metal materials. It is possible.
For example, the portion of the head body 12 excluding the large specific gravity portion 48 is made of titanium alloy (specific gravity 4.4), and the face back 28 has a large specific gravity portion 48 as stainless steel (specific gravity 7.8) or tungsten alloy (specific gravity 9 to 9 to). 18) may be provided.
Alternatively, the portion of the head body 12 excluding the large specific gravity portion 48 may be made of titanium alloy (specific gravity 4.4), and the face portion 14 may be made of β titanium (specific gravity 4.8).
The large specific gravity portion 48 is, for example, a portion 48A constituting the face portion 14 or a portion 48B constituting the face back 28.

Here, a method of measuring the moment of inertia MI of the golf club head 10 will be described in detail with reference to FIGS. 19 to 22.
Here, FIG. 19 is a schematic perspective view showing a moment of inertia measuring instrument of the golf club head 10. The moment of inertia MI is measured by the moment of inertia measuring device 60 shown in FIG.

The moment of inertia measuring device 60 includes a measuring unit 62, a calculation unit 64, a start lever 66, a display unit 68, and an operation button 69. An object to be measured for the moment of inertia MI is placed on the measuring unit 62, and the start lever 66 After the hand is picked and displaced by hand, the hand is released to twist and vibrate, the moment of inertia MI is measured through the calculation unit 64 by measuring the period of the twisting vibration at this time, and the numerical value of the moment of inertia MI is displayed on the display unit 68. It is a display device.
As the moment of inertia measuring device 60, Model MOI-005-014 manufactured by Inertia Dynamics Co., Ltd. is exemplified. Such a moment of inertia measuring instrument may be a known one, and is not particularly limited in the present invention.

As shown in FIG. 20A, the jig 70 is fixed to the moment of inertia measuring device 60, and the moment of inertia Ia of the jig 70 is measured.
Next, as shown in FIG. 20B, the sole portion 18 of the golf club head 10 is fixed to the upper surface portion 72 of the jig 70, and the total moment of inertia Ib of the golf club head 10 and the jig 70 is measured. .. Next, the moment of inertia MI of the golf club head 10 is obtained from (Ib-Ia) from the obtained moments of inertia Ia and Ib.
In the normal moment of inertia measuring instrument 60, the numerical value of Ia is automatically tare by a series of procedures by making full use of the operation button 69, and the numerical value of (Ib-Ia) is displayed.

In order to fix the golf club head 10 and the jig 70, for example, fixing with a double-sided tape, an adhesive such as clay, fixing with an adhesive, or fixing with a magnetic force can be mentioned.
For fixing, the sole portion 18 of the golf club head 10 is fixed to the upper surface portion 72 of the jig 70. However, if the sole portion 18 has a convex curved surface, the upper surface portion 72 is preferably a concave curved surface that matches the convex curved surface, and if the sole portion 18 is a flat surface, the upper surface portion 72 is It is preferably flat. That is, it is preferable that both sides to be fixed match.
When the sole portion 18 of the golf club head 10 has a curved surface, an adhesive body (not shown) is provided so as to match the sole portion 18 and the upper surface portion 72, and the golf club head 10 is fixed. In this case, it goes without saying that a sticky body having an internal mass of a fixing means such as an adhesive is included in a part of the jig, and in tare pulling, it is pulled as a tare like the jig.

The golf club head 10 passes through the center of gravity G0 of the golf club head 10 shown in FIG. 21 (A), passes through the first straight line V orthogonal to the horizontal plane HP, and twists the moment of inertia measuring instrument 60 shown in FIG. 21 (B). It is preferable that the rotation axis R of the vibration is fixed to the moment of inertia measuring device 60 so as to coincide with or substantially match as shown in FIG. 21 (C).
Approximately the same means that the distance between the point where the rotation axis R passes through the horizontal plane HP and the point p where the first straight line V passes through the horizontal plane HP is within 3 mm, preferably within 2 mm, and more preferably within 1 mm. ..
By fixing the sole portion 18 of the golf club head 10 within this range, the moment of inertia MI of the golf club head 10 can be measured more accurately.

Further, it is not always necessary that the distance between the point where the rotation axis R passes through the horizontal plane HP and the point p where the first straight line V passes through the horizontal plane HP is within the above range, and this distance is known to automatically tare. It can be corrected by subtracting the product of the mass of the golf club head 10 multiplied by the square of this distance from the numerical value of (Ib-Ia) obtained in the above steps.
The moment of inertia MI of the golf club head 10 may be obtained by this correction method. As described above, the method of measuring the moment of inertia MI of the golf club head 10 is not particularly limited.

The rotation axis R of the moment of inertia measuring device 60 and the point at which the rotation axis R passes through the sole portion 18 are determined by the moment of inertia measuring device 60. The rotation axis R is preferably vertical or substantially vertical.
Here, the term "vertical" means that the inclination with respect to the vertical direction is within 2 °, preferably within 1 °. In order to set the rotation axis R vertically or almost vertically, adjust the level of the measuring instrument with reference to the spirit level provided in the moment of inertia measuring instrument 60, or adjust the measuring instrument horizontally. It is possible to install it on the top.
By setting within the above range, the moment of inertia MI around the rotation axis with the first straight line V passing through the center of gravity G of the golf club head 10 and orthogonal to the horizontal plane HP as the first rotation axis can be measured more accurately. Can be done.

Further, it is preferable that the plane supported by the upper surface portion 72 of the jig 70 is horizontal or substantially horizontal. Approximately horizontal in the present invention means that the inclination with respect to the horizontal plane HP is within 2 °, preferably within 1 °.
By setting within the above range, the moment of inertia MI of the golf club head 10 can be measured more accurately.

Further, it is preferable that the jig 70 is mounted on the moment of inertia measuring device 60 so that the position of the center of gravity of the jig itself coincides with or substantially coincides with the rotation axis R. In general, when the center of gravity position of the jig 70 is C as shown in FIG. 22, the distance δ between the center of gravity position C and the rotation axis R is within 2 mm, preferably within 1 mm.
By setting the position C of the center of gravity of the jig 70 within the above range, the moment of inertia MI of the golf club head 10 can be measured more accurately.

As described above, according to the present embodiment, as shown in FIG. 4, the opening 32 formed in the hollow head body 12 formed of the metal material is formed from the outside of the head body 12 with the fiber reinforced resin material. The cover body 46 is closed by the cover body 46 composed of the cover body 46, and the cover body 46 faces the space 13 through the opening 32 at a substantially central position of the second range A2 partitioned by the fifth plane P5 and the sixth plane P6. A rib 40 made of a metal material that supports the inner surface portion of the space 13 from the space 13 side is formed so as to extend in the toe heel direction so as to cross the opening 32.
Therefore, the cover body 46 is arranged at a position near the center of gravity point G0 of the golf club head 10, and the portion of the head body 12 made of a metal material having a heavier specific gravity than the cover body 46 is located at a position far from the center of gravity point G0. By arranging the golf club head 10, the moment of inertia MI of the golf club head 10 can be secured, which is advantageous in improving the directionality of the hit ball.
Further, the cover body 46 is reinforced by supporting the cover body 46 by ribs 40 having higher rigidity than the cover body 46, thereby exhibiting the same effect as increasing the rigidity and elastic modulus of the cover body 46. be able to.
Therefore, despite the structure in which the opening 32 is closed by the cover body 46 having a lower rigidity and elastic modulus than the head body 12 made of a metal material, the hitting sound generated at the time of hitting can be made high-pitched, which is comfortable. It is advantageous in obtaining the hitting sound.

Hereinafter, experimental examples of the present invention will be described.
23 to 28 are diagrams showing the experimental results of the golf club head 10 according to the present invention.
A golf club head 10 as a sample was prepared for each experimental example, and the following four evaluation items were measured to obtain indexes (evaluation points), and the total points of the four indexes were obtained.
In the following experimental example, a driver was used as the golf club head 10 as an experimental target.

(1) Hitting sound The hitting sound when a golf ball was actually hit using the golf club head 10 of each experimental example for 20 subjects was evaluated by an index.
The index of the experimental example corresponding to the comparative example is set to 100, and the larger the index is, the higher the hitting sound is and the more comfortable the hitting sound is, and the better the evaluation is.
In the evaluation of the hitting sound, 20 golfers actually hit the golf ball 10 times at a time for each golf club head 10, and the average value was calculated.

(2) Variation in flight distance The variation in flight distance when a golf ball was actually hit by the golf club head 10 of each experimental example for 20 subjects was evaluated by an index.
Here, the variation in flight distance is obtained as follows.
The difference between the maximum value and the minimum value of the flight distance is calculated as the variation of the flight distance.
The evaluation data of the flight distance variation was obtained for each of the 20 subjects using the golf clubs of each experimental example, and the average value of the evaluation data of the flight distance variation of 20 persons was obtained for each of the golf clubs.
Then, the average value of the evaluation data of the experimental examples corresponding to the comparative examples is set to 100, and the experimental examples other than the comparative examples are indexed (the average value of the evaluation data of the experimental examples corresponding to the comparative examples / the evaluation of the experimental examples other than the comparative examples. It was evaluated by the average value of the data) × 100). That is, the higher the index, the smaller the variation in flight distance and the better.

(3) Left-right variation The left-right variation when a golf ball was actually hit by the golf club head 10 of each experimental example for 20 subjects was evaluated by an index.
Here, the left-right variation is obtained as follows.
That is, a target point is set in the hitting field and the golfer hits the ball toward the target point. Then, the distance between the straight line connecting the hitting point and the target point and the point where the hit ball stops is recorded as the directional blur width (yard).
The amount of deviation to the right with respect to the target flying ball line Lg is displayed as a positive (+) value, and the amount of deviation to the left is displayed as a negative (-) value, and all values are measured values of 10 balls. Was calculated as the evaluation data of the left-right variation.
Here, the evaluation data of the left-right variation was obtained for each of the 20 subjects using the golf clubs of each experimental example, and the average value of the evaluation data of the left-right variation of 20 subjects was obtained for each of the golf clubs. Then, the average value of the evaluation data of the experimental examples corresponding to the comparative examples is set to 100, and the experimental examples other than the comparative examples are indexed ((the average value of the evaluation data of the experimental examples corresponding to the comparative examples / the experimental examples other than the comparative examples). It was evaluated by the average value of the evaluation data) × 100). That is, the higher the index, the smaller the left-right variation and the better.

(4) Durability The golf ball is repeatedly hit on the face surface 14A of the golf club head 10 fixed to the shaft with an air cannon, and the number of hits required until the face portion 14 is deformed or damaged is measured and the number of hits is measured. Was indexed. The ball speed was 50 m / s. The hitting point position was the center point Pc of the face surface 14A.
In this case, the measurement result of the golf club head 10 of the experimental example corresponding to the comparative example is shown as an index of 100. The larger the index, the better the evaluation.

(5) Total score The total score was the sum of the above-mentioned four indexes of hitting sound, flight distance variation, left-right variation, and durability.
The total score of the experimental examples corresponding to the comparative examples is set to 400, and the larger the total score, the better the evaluation.

The golf club head 10 of the experimental example will be described below.
The golf club head 10 used in the experimental examples is a driver, and has the following conditions in common except for the parameters specified in the experimental examples.
Material of head body 12: Titanium alloy Ti-8Al-1Mo-1V
Face 14 material: Ti-6Al-4V
Material of cover body 46: CFRP (carbon fiber reinforced resin)
Cover body 46 thickness Tc: 0.6 mm
However, in Experimental Examples 2 to 20, it was assumed that the face back 28 was provided with a stainless alloy (specific gravity 7.8) mass of 30 g as the large specific gravity portion 48.
Loft angle 10.5 °
Rye angle 59 °
Head volume 460cc

(Condition 1)
As shown in FIG. 23, the conditions specified in claim 1 were changed for each experimental example.
The conditions specified in claims 2 to 8 are fixed as follows.
That is, the dimension in the toe-heel direction of the portion where the rib 40 supporting the cover body 46 as defined in claim 2 does not satisfy the provision that the dimension in the toe-heel direction of the cover body 46 is substantially the same as the total length. Specifically, the toe-heel direction dimension of the portion where the rib 40 supports the cover body 46 is 60% of the total length of the toe-heel direction dimension of the cover body 46, which is less than the preferable 70%.
That is, as shown in FIG. 38 (B), the dimension in the toe heel direction (Lth1 + Lth2 + Lth3) of the portion where the rib 40 supports the cover body 46 is 70% of the total length (Lc1) of the dimension in the toe heel direction of the cover body 46. Is below.
Further, the rib 40 defined in claim 3 satisfies the provision that the rib 40 is formed so as to extend over 80% or more of the entire circumference of the inner surface of the golf club head 10 including the inner surface of the cover body 46 and the inner surface of the head body 12. Specifically, the rib 40 is formed so as to extend over 70% of the entire circumference of the inner surface of the golf club head 10.
The dimensions of the rib 40 are as follows, and are the same in all experimental examples except Experimental Example 1.
Height of rib 40 H: 5 mm
Rib 40 thickness D: 1 mm
Width of rib 40 W: 5 mm
Further, it is assumed that the boundary portion 30 specified in claim 4 is formed with a width of 5 mm.
The thick portion 31 (FIG. 9B) specified in claim 5 is assumed to have a thickness of 3 mm and a length of 50 mm.
The head mass specified in claim 6 was 200 g, and the moment of inertia MI was 5500 g · cm ² , both of which were within the specified range.
The head volume specified in claim 7 was 460 cc, and the maximum head width M was 125 mm, both of which were within the specified range.
In the large specific gravity portion 48 defined in claim 8, a stainless alloy is arranged on the face back 28 side.

Experimental Example 1 corresponds to a comparative example, and although not shown, the entire head body 12 is made of a metal material (titanium alloy), does not have an opening 32 or a cover body 46, and has a rib 40. It is a general golf club head (driver) that is not formed.

In Experimental Example 2, as shown in FIG. 29, the cover body 46 defined in claim 1 is located at a position deviated from the first range A1 toward the face portion 14, which is outside the scope of the present invention.
The rib 40 defined in claim 1 is located at a substantially central position of the second range A2 (located within the fifth range A5).
As shown in FIG. 29, an opening is formed on the face portion 14 side of the head main body 12, and the face portion 14 is joined by welding or the like. Therefore, the opening 32 and the cover body 46 are provided in a range excluding the face portion 14.
In FIGS. 29-37 showing an experimental example, the shapes (vertical plate portion 36, horizontal plate portion 38) of the mounting portion 34 of the head main body 12 are not shown in order to simplify the drawing.

In Experimental Example 3, as shown in FIG. 30, the cover body 46 defined in claim 1 is located at a position outside the first range A1 toward the face back 28, which is outside the scope of the present invention.
The rib 40 defined in claim 1 is located at a substantially central position of the second range A2 (located within the fifth range A5).

In Experimental Example 4, as shown in FIG. 31, the cover body 46 specified in claim 1 is located within the first range A1, but the rib 40 specified in claim 1 is substantially equal to the second range A2. It is located at a position deviated from the central position toward the face portion 14 (a portion deviated from the fifth range A5), which is outside the scope of the present invention.

In Experimental Example 5, as shown in FIG. 32, the cover body 46 defined by claim 1 is located within the first range A1, but the rib 40 defined by claim 1 is substantially the same as that of the second range A2. It is located at a position deviated from the central position toward the face back 28 side (a portion deviated from the fifth range A5), which is outside the scope of the present invention.

In Experimental Example 6, as shown in FIG. 33, the cover body 46 specified in claim 1 is located in the first range A1, and the rib 40 specified in claim 1 is substantially in the center of the second range A2. It is located in position (located within the fifth range A5) and is within the scope of the present invention.

Therefore, as shown in FIG. 23, although Experimental Example 3 slightly exceeds Experimental Example 6 in terms of durability, Experimental Example 6 satisfying the provision of claim 1 has hitting sound, flight distance variation, left-right variation, and so on. The durability and the total score are higher than those of Experimental Examples 1-5, which are outside the scope of the present invention.

(Condition 2)
As shown in FIG. 24, the conditions specified in claim 1 are set to constant conditions within the specified range, the conditions specified in claim 2 are changed, and the conditions specified in claim 3-8 are set to constant conditions. did.
That is, as shown in FIG. 4, the cover body 46 specified in claim 1 is located in the first range A1, and the rib 40 specified in claim 1 is located substantially in the center position of the second range A2. (Located within the fifth range A5), which is within the scope of the present invention.
Further, the rib 40 defined in claim 3 is formed so as to extend over 100% of the entire circumference of the inner surface of the golf club head 10 including the inner surface of the cover body 46 and the inner surface of the head body 12.
Further, it is assumed that the boundary portion 30 specified in claim 4 is formed with a width of 5 mm.
The thick portion 31 (FIG. 9B) specified in claim 5 is assumed to have a thickness of 3 mm and a length of 50 mm.
The head mass specified in claim 6 was 200 g, and the moment of inertia MI was 5500 g · cm ² , both of which were within the specified range.
The head volume specified in claim 7 was 460 cc, and the maximum head width M was 125 mm, both of which were within the specified range.
In the large specific gravity portion 48 defined in claim 8, a stainless alloy is arranged on the face back 28 side.
As shown in FIG. 24, in Experimental Example 7, the dimension in the toe heel direction of the portion where the rib 40 defined in claim 2 supports the cover body 46 is substantially the same as the total length of the dimension in the toe heel direction of the cover body 46. Does not meet the requirement of.
Specifically, the dimension in the toe-heel direction of the portion where the rib 40 supports the cover body 46 is 66% of the total length of the dimension in the toe-heel direction of the cover body 46, which is less than the preferable 70%.
That is, as shown in FIG. 38 (B), the dimension in the toe heel direction (Lth1 + Lth2 + Lth3) of the portion where the rib 40 supports the cover body 46 is 70% of the total length (Lc1) of the dimension in the toe heel direction of the cover body 46. Is below.
Experimental Example 8 satisfies the provision that the dimension in the toe-heel direction of the portion where the rib 40 supports the cover body 46 specified in claim 2 is substantially the same as the total length of the dimension in the toe-heel direction of the cover body 46. There is.
Specifically, the dimension of the portion where the rib 40 supports the cover body 46 in the toe heel direction is 75% of the total length of the cover body 46 in the toe heel direction, which is more than 70%.
That is, as shown in FIG. 38 (A), the dimension in the toe heel direction (Lth1 + Lth2 + Lth3) of the portion where the rib 40 supports the cover body 46 is 70% of the total length (Lc1) of the dimension in the toe heel direction of the cover body 46. Is exceeded.

Therefore, although Experimental Example 7 slightly exceeds Experimental Example 8 in terms of durability, Experimental Example 8 satisfying all the provisions of claims 1 and 2 is advantageous in ensuring the strength and rigidity of the cover body 46. Therefore, the effect of making the hitting sound high is ensured, and the hitting sound, the flight distance variation, the left-right variation, and the total points are within the scope of the present invention, but substantially exceed the experimental example 7 which does not satisfy the provision of claim 2. There is.

(Condition 3)
As shown in FIG. 25, the conditions specified in claims 1 and 2 are set as constant conditions within the specified range, and the conditions specified in claim 3 are changed to the conditions specified in claim 4-8. Was a fixed condition.
That is, as shown in FIG. 4, the cover body 46 specified in claim 1 is located in the first range A1, and the rib 40 specified in claim 1 is located substantially in the center position of the second range A2. (Located within the fifth range A5), which is within the scope of the present invention.
Further, the dimension in the toe heel direction of the portion where the rib 40 supporting the cover body 46 specified in claim 2 is substantially the same as the total length of the dimension in the toe heel direction of the cover body 46 (70%), which is within the regulation. And said.
Further, it is assumed that the boundary portion 30 specified in claim 4 is formed with a width of 5 mm.
The thick portion 31 (FIG. 9B) specified in claim 5 is assumed to have a thickness of 3 mm and a length of 50 mm.
The head mass specified in claim 6 was 200 g, and the moment of inertia MI was 5500 g · cm ² , both of which were within the specified range.
The head volume specified in claim 7 was 460 cc, and the maximum head width M was 125 mm, both of which were within the specified range.
In the large specific gravity portion 48 defined in claim 8, a stainless alloy is arranged on the face back 28 side.
As shown in FIGS. 25 and 38 (A), in Experimental Example 9, the length of the rib 40 defined in claim 3 is 75% of the entire circumference of the inner surface of the golf club head 10, and is 80% or more. not filled.
In Experimental Example 10, as shown in FIG. 38 (B), the length of the rib 40 defined in claim 3 is set to 85% of the entire circumference of the inner surface of the golf club head 10, and satisfies the provision of 80% or more. ..

Therefore, Experimental Example 10 satisfying all the provisions of claims 1, 2 and 3 is more advantageous in ensuring the strength and rigidity of the cover body 46, so that the effect of making the hitting sound high is ensured and the hitting sound is obtained. , The variation in flight distance, the variation on the left and right, the durability, and the total score exceed the experimental example 9 which does not satisfy the provision of claim 3.

(Condition 4)
As shown in FIG. 26, the conditions specified in claims 1-3 are set to constant conditions within the specified range, and the conditions specified in claims 4 and 5 are changed to the conditions specified in claims 6-8. Was a fixed condition.
That is, as shown in FIG. 4, the cover body 46 specified in claim 1 is located in the first range A1, and the rib 40 specified in claim 1 is located substantially in the center position of the second range A2. (Located within the fifth range A5), which is within the scope of the present invention.
Further, the dimension in the toe heel direction of the portion where the rib 40 supporting the cover body 46 specified in claim 2 is substantially the same as the total length of the dimension in the toe heel direction of the cover body 46 (70%), which is within the regulation. And said.
Further, the length of the rib 40 specified in claim 3 is set within the specified value as 100% of the entire circumference of the inner surface of the golf club head 10.
The head mass specified in claim 6 was 200 g, and the moment of inertia MI was 5500 g · cm ² , both of which were within the specified range.
The head volume specified in claim 7 was 460 cc, and the maximum head width M was 125 mm, both of which were within the specified range.
In the large specific gravity portion 48 defined in claim 8, a stainless alloy is arranged on the face back 28 side.
As shown in FIG. 39, in Experimental Example 11, there is no boundary portion (metal portion) 30 specified in claim 4, and there is no thick portion 31 specified in claim 5, and the provisions of claims 4 and 5 are not provided. Does not meet.
In Experimental Example 12, the width of the boundary portion 30 specified in claim 4 is 5 mm, the thickness of the thick portion 31 specified in claim 5 is 0.5 mm, and the length is 50 mm. Although the provision of item 4 is satisfied, the thickness of the thick portion 31 specified in claim 5 is less than 1 mm.
In Experimental Example 13, the width of the boundary portion 30 specified in claim 4 is 5 mm, the thickness of the thick portion 31 specified in claim 5 is 3 mm, and the length is 50 mm. It meets the provisions of 5.

Therefore, in Experimental Example 13 that satisfies all the provisions of claims 1-5, since the boundary portion 30 and the thick portion 31 satisfy the provisions, the moment of inertia MI is secured while ensuring the strength of the head body 12. In order to be more advantageous in the above, the hitting sound, the flight distance variation, the left-right variation, the durability, and the total points exceed the experimental examples 11 and 12 which do not satisfy the provisions of claims 4 and 5.

(Condition 5)
As shown in FIG. 27, the conditions specified in claims 1-5 and 8 are set to constant conditions within the specified range, and the conditions specified in claims 6 and 7 are changed.
That is, as shown in FIG. 4, the cover body 46 specified in claim 1 is located in the first range A1, and the rib 40 specified in claim 1 is located substantially in the center position of the second range A2. (Located within the fifth range A5), which is within the scope of the present invention.
Further, the dimension in the toe heel direction of the portion where the rib 40 supporting the cover body 46 specified in claim 2 is substantially the same as the total length of the dimension in the toe heel direction of the cover body 46 (70%), which is within the regulation. And said.
Further, the length of the rib 40 specified in claim 3 is set within the specified value as 100% of the entire circumference of the inner surface of the golf club head 10.
The boundary portion 30 specified in claim 4 has a width of 5 mm and is within the specified range.
The thick portion 31 specified in claim 5 has a thickness of 3 mm and a length of 50 mm, and is within the specified range.
In the large specific gravity portion 48 defined in claim 8, a stainless alloy is arranged on the face back 28 side.

As shown in FIG. 27, in Experimental Example 14, the head mass specified in claim 6 was 175 g and the moment of inertia MI was 4500 g · cm ² , which was within the specified range, but the preferable head mass was 180 to 205 g and the moment of inertia MI was 50000. The value deviated from 6000 g · cm ² .
Further, the head volume specified in claim 7 is 460 cc, the maximum head width M is 125 mm, which is within the specified range, and the preferable head volume is 440 to 470 cc, and the maximum head width is 120 to 127 mm.
In Experimental Example 15, the head mass specified in claim 6 is 200 g and the moment of inertia MI is 4400 g · cm ² , which is within the specified range and is in the range of a preferable head mass of 180 to 205 g, but a preferable moment of inertia MI of 5000 to 6000 g. The value deviated from cm ² . ..
Further, the head volume specified in claim 7 is 420 cc, the maximum head width M is 118 mm, which is within the specified range, and the preferable head volume is 440 to 470 cc, and the maximum head width is 120 to 127 mm.
Ta.
Further, in Experimental Example 16, the head mass specified in claim 6 is 200 g, the moment of inertia MI is 5500 g · cm ² , and the value is within the specified range, and the preferable head mass is in the range of 180 to 205 g, and the preferred moment of inertia MI is 5000 to 6000 g. -It was within the range of cm ² .
Further, the head volume specified in claim 7 is 460 cc, the maximum head width M is 125 mm, which is within the specified range, and the preferable head volume is 440 to 470 cc, and the maximum head width is 120 to 127 mm.

Therefore, Experimental Example 16 satisfying all the provisions of claims 1-7 is more advantageous in securing the moment of inertia MI because the head mass, the moment of inertia MI, the head volume, and the maximum width of the head satisfy the provisions. Therefore, the hitting sound is equal to or higher than that of Experimental Examples 14 and 15 that do not satisfy the provisions of claim 6 or 7, and the flight distance variation, left-right variation, durability, and total points are claimed 6 or claim 7. It exceeds the experimental examples 14 and 15 that do not satisfy the provision of 7.

(Condition 6)
As shown in FIG. 28, among claims 1-8, the conditions specified in claim 1 are changed within the specified range, and the conditions specified in claim 2-8 are set as constant conditions within the specified conditions.
Further, the dimension in the toe heel direction of the portion where the rib 40 supporting the cover body 46 specified in claim 2 is substantially the same as the total length of the dimension in the toe heel direction of the cover body 46 (70%), which is within the regulation. And said.
Further, the length of the rib 40 specified in claim 3 is set within the specified value as 100% of the entire circumference of the inner surface of the golf club head 10.
The boundary portion 30 specified in claim 4 has a width of 5 mm and is within the specified range.
The thick portion 31 specified in claim 5 has a thickness of 3 mm and a length of 50 mm, and is within the specified range.
The head mass specified in claim 6 was 200 g, and the moment of inertia MI was 5500 g · cm ² , both of which were within the specified range.
The head volume specified in claim 7 was 460 cc, and the maximum head width M was 125 mm, both of which were within the specified range.
In the large specific gravity portion 48 defined in claim 8, a stainless alloy is arranged on the face back 28 side.
Therefore, the following Experimental Examples 17 to 20 all satisfy the provisions of claims 1-8.
As shown in FIG. 34, in Experimental Example 17, the cover body 46 is located between the central surface P0 and the fourth plane P4.
Further, the plane parallel to the central surface P0 passing through the position α / 4 separated from the central position β of the second range A2 in the face portion 14 direction is defined as the seventh plane P7, and the face back 28 from the central position β of the second range A2. Assuming that the plane parallel to the central plane P0 passing through the positions separated by α / 4 in the direction is the eighth plane P8, the range divided by the plane P20 parallel to the central plane P0 and located at the central position β and the eighth plane P8. The rib 40 is located approximately in the center of the (within the fifth range A5).

As shown in FIG. 35, in Experimental Example 18, the cover body 46 is located between the central surface P0 and the third plane P3.
Further, the plane parallel to the central surface P0 passing through the position α / 4 separated from the central position β of the second range A2 in the face portion 14 direction is defined as the seventh plane P7, and the face back 28 from the central position β of the second range A2. Assuming that the plane parallel to the central plane P0 passing through the positions separated by α / 4 in the direction is the eighth plane P8, the range divided by the plane P20 parallel to the central plane P0 and located at the central position β and the seventh plane P7. The rib 40 is located approximately in the center of the (within the fifth range A5).

As shown in FIG. 36, in Experimental Example 19, the cover body 46 has a tenth plane P10 in which the central surface P0 is translated to the face portion 14 side by M / 8 minutes, and the central surface P0 is M to the face back 28 side. It is located between the 11th plane P11 which was translated by / 8 minutes.
Further, the plane passing through the position α / 4 separated from the central position β of the second range A2 in the face portion 14 direction and parallel to the central surface P0 is defined as the seventh plane P7, and the face back 28 from the central position β of the second range A2. Assuming that the plane parallel to the central plane P0 passing through the positions separated by α / 4 in the direction is the eighth plane P8, it is approximately in the center of the range partitioned by the seventh plane P7 and the eighth plane P8 (within the fifth range A5). The rib 40 is located.

As shown in FIG. 37, in Experimental Example 20, the cover body 46 is located between the fifth plane P5 and the sixth plane P6.
Further, the plane passing through the position α / 4 separated from the central position β of the second range A2 in the face portion 14 direction and parallel to the central surface P0 is defined as the seventh plane P7, and the face back 28 from the central position β of the second range A2. Assuming that the plane parallel to the central plane P0 passing through the positions separated by α / 4 in the direction is the eighth plane P8, it is approximately in the center of the range partitioned by the seventh plane P7 and the eighth plane P8 (within the fifth range A5). The rib 40 is located.

Therefore, Experimental Examples 17 to 20 satisfying all the provisions of claims 1-8 are advantageous in securing the moment of inertia MI and making the hitting sound high-pitched, so that the hitting sound, the flight distance variation, and the left and right are left and right. The variation, durability, and total score are almost higher than those of other Experimental Examples 1 to 16.

(Modification example)
FIG. 40 shows a modified example of the first embodiment.
In this modification, in addition to the rib 40, a support plate portion 60 for supporting the cover body 40 is separately provided.
The support plate portion 60 is made of the same metal material as the head body 12.
The support plate portion 60 supports a portion of the inner surface of the cover body 46 with the cover body 46 facing the space 13 via the first opening 32A from the space 13 side.
The support plate portion 60 is formed so as to extend along the direction connecting the face portion 14 and the face back 28 so as to cross the first opening 32A.
The outer surface of the support plate portion 60 superimposed on the inner surface of the cover body 46 is provided at a position displaced inside the head main body 12 by the thickness Tc of the cover body 46 rather than the outer surface of the head main body 12.
Both ends of the support plate portion 60 are connected to the horizontal plate portion 38, and at the intersection of the support plate portion 60 and the horizontal plate portion 38, the outer surface of the support plate portion 60 and the outer surface of the horizontal plate portion 38 are on the same surface. Is located in.

The inner surface of the cover body 46 is overlapped with the outer surface of the horizontal plate portion 38 of the mounting portion 34 and the outer surface of the boundary portion 30, the outer surface of the support wall portion 42 of the rib 40, and the outer surface of the support plate portion 60 from the outside of the head body 12. In a state where the cover body 46 is fitted inside the vertical plate portion 36 and closes the openings 32A to 32C, the mounting portion 34 and the support wall portion 42 of each rib 40 and the support wall portion 42 of each rib 40 are formed by a conventionally known bonding method such as adhesion or caulking. It is attached to the support plate portion 60 (integrally coupled), whereby the golf club head 10 is assembled.
According to such a modification, since the rigidity of the head body 12 is increased by the support wall portion 60, it is more advantageous in making the hitting sound generated at the time of hitting a high-pitched sound, and more advantageous in obtaining a comfortable hitting sound. Become.
In this example, the case where one support plate portion 60 is provided substantially in the center of the first opening 32A in the toe heel direction is shown, but a plurality of support plate portions 60 are provided at intervals in the toe heel direction. You may.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. 41.
In the following embodiments, the same parts and members as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and the description thereof will be omitted.
The second embodiment is different from the first embodiment in that the rib 40 is omitted and the large specific gravity portion 50 is provided on the face back 28 side.

As shown in FIG. 40, the golf club head 10A includes a head main body 12A and a cover body 46 configured in the same manner as in the first embodiment, and the head main body 12A has a first embodiment. Openings 32 (first to third openings 32A to 32C) similar to the above are provided.
In the reference state of 10A of the golf club head, the plane that is orthogonal to the horizontal plane HP and the face center reference cross section Pfc and abuts on the leading edge 26 is set as the first plane P1, and is parallel to the first plane P1 and abuts on the outer surface of the face back 28. The plane is the second plane P2, and the distance between the first plane P1 and the second plane P2 is the maximum head width M when the head body 12A is viewed in a plane.
The plane parallel to the first plane P1 and the second plane P2 at a position halved in the dimension connecting the first plane P1 and the second plane P2 is defined as the central plane P0.
A plane parallel to the central surface P0 at a position separated from the central surface P0 on the face side by 1/4 of the maximum head width M is referred to as a third plane P3.
A plane parallel to the center plane P0 at a position separated from the center plane P0 on the face back 28 side by 1/4 of the maximum head width M is referred to as a fourth plane P4.
The cover body 46 is located in the first range A1 partitioned by the third plane P3 and the fourth plane P4.
The portion of the head body 12A located in the fourth range A4 from the fourth plane P4 to the face back 28 is formed of a (metal) material having a specific gravity larger than the specific gravity of the remaining portion excluding the fourth range A4. A large specific gravity portion 50 is provided.
For example, the large specific gravity portion 50 is made of a tungsten alloy (specific gravity 12), and the head body 12A excluding the large specific gravity portion 50 is made of a titanium alloy (specific gravity 4.4).

According to the second embodiment, the opening 32 formed in the hollow head main body 12 made of a metal material is closed from the outside of the head main body 12 with a cover body 46 made of a fiber reinforced resin material.
Therefore, the cover body 46 is arranged near the center of gravity point G0 of the golf club head 10, and the large specific gravity portion 50 made of a metal material having a heavier specific gravity than the cover body 46 is far from the center of gravity point G0. By arranging the golf club head 10 at the above location, the moment of inertia MI of the golf club head 10 can be secured, which is advantageous in improving the direction of the hit ball.
Further, since the large specific gravity portion 50 is provided at the position closest to the face back 28, which is the starting point of the vibration at the time of hitting the ball, the vibration generated at the time of hitting the ball is heavy through the portion of the head body 12A. In the process of transmitting to the large specific gravity portion 50, an action similar to the so-called mass damper function occurs, and the vibration is damped.
At this time, since the lower frequency vibration component of the vibration is more likely to be attenuated, the low frequency component is attenuated in the hitting sound, while the high frequency component is not so attenuated.
Therefore, despite the structure in which the opening 32 is closed by the cover body 46 having a lower rigidity and elastic modulus than the head body 12A made of a metal material, the hitting sound generated at the time of hitting can be made high-pitched, which is comfortable. It is advantageous in obtaining the hitting sound.

Next, a modified example of the second embodiment will be described with reference to FIG. 42.
In the modified example, in addition to providing the large specific gravity portion 50 on the face back 28, the large specific gravity portion 52 is also provided on the face portion 14, which is different from the second embodiment.
That is, most (or all) of the face portion 14 was composed of a large specific gravity portion 52 using β titanium DAT55G (specific gravity 4.7).
Therefore, the remaining head body 12 except for the large specific gravity portion 50 made of a tungsten alloy (specific gravity 12) and the large specific gravity portion 52 made of β-titanium DAT55G (specific gravity 4.7) is a titanium alloy (specific gravity 4.4). That is, the specific gravity of the portion of the head main body 12 located in the fourth range A4 is the rear specific gravity Ga, and the third range of the head main body 12 is divided by the first plane P1 and the third plane P3. When the specific gravity of the portion located in A3 is the front specific gravity Gb and the specific gravity of the portion of the head body 12 located in the first range A1 is the intermediate specific gravity Gc, the following equation (1) is satisfied.
Ga>Gb> Gc …… (1)
With such a configuration, in addition to the effect of the second embodiment, the two large specific gravity parts 50 and 52 are arranged at a position away from the center of gravity point G0, so that the moment of inertia MI is made larger. The effect of being advantageous in securing is achieved.

Hereinafter, the golf club head 10 of the experimental example reflecting the second embodiment and the modified example thereof will be described.
The head body 12A of the experimental example was prepared as follows in the same manner as in the first embodiment.
Material of head body 12: Titanium alloy Ti-8Al-1Mo-1V
Face 14 material: Ti-6Al-4V
Material of cover body 46: CFRP (carbon fiber reinforced resin)
Cover body 46 thickness Tc: 0.6 mm
The material of the large specific gravity portion 50: a tungsten alloy (specific gravity 12) having a mass of 60 g was provided.
Material of large specific gravity portion 52: β titanium DAT55G (specific gravity 4.7) with a mass of 58 g was provided.
Loft angle 10.5 °
Rye angle 59 °
Head volume 460cc

As shown in FIG. 43, experiments were conducted on Experimental Example 1 which is a comparative example, Experimental Example 21 which satisfies the provision of claim 9, and Experimental Example 22 which satisfies the provision of claim 10.
As shown in FIG. 41, Experimental Example 21 satisfying the provision of claim 9 is advantageous in securing the moment of inertia MI and making the hitting sound high-pitched, so that the hitting sound, the flight distance variation, and the left-right variation , Durability, and total score exceed Experimental Example 1, which is outside the scope of the present invention.
Further, since Experimental Example 22 satisfying the provision of claim 10 is more advantageous in securing the moment of inertia MI, the evaluation of hitting sound, variation in flight distance, and variation in left and right is higher than that in Experimental Example 21. The total score is also high.

10, 10A Golf club head 12, 12A Head body 13 Space 14 Face part 16 Crown part 18 Sole part 20 Side part 22 Toe 24 Heel 26 Leading edge 28 Face back 29 Hosel 30 Boundary part 31 Thick part 32 Opening 32A 1st Opening 32B 2nd opening 32C 3rd opening 34 Mounting part 40 Rib 40A 1st rib part 40B 2nd rib part 40C 3rd rib part 40D 4th rib part 40E 5th rib part 42 Support wall part 44 Reinforcing wall part 46 Cover body 46A Toe side cover body 46B Heel side cover body 48 Large specific gravity part 50 Large specific gravity part 52 Large specific gravity part Pfc Face center reference cross section P0 Center plane P1 First plane P2 Second plane P3 Third plane P4 Fourth plane P5 5th plane P6 6th plane A1 1st range A2 2nd range A3 3rd range A4 4th range HP horizontal plane M Head maximum width

Claims (9)

A face portion having a vertical height and extending to the left and right, a crown portion extending rearward from the upper part of the face portion, a sole portion extending rearward from the lower portion of the face portion, and the crown portion. A hollow head in which a metal material is formed between the sole portion and a side portion extending between the toe side edge and the heel side edge of the face portion through a face back, and the inside thereof is a space. With the main body
A cover body made of a fiber-reinforced resin material that closes openings formed at at least one of the crown portion, the side portion, and the sole portion from the outside of the head body.
A hollow golf club head equipped with
In a reference state in which the golf club head is installed according to a predetermined lie angle and loft angle with respect to the horizontal plane, the head body is broken at a plane including a normal passing through the center point of the face surface and orthogonal to the horizontal plane. The cross section is used as the face center reference cross section.
In the reference state, the horizontal plane and the plane orthogonal to the face center reference cross section and in contact with the leading edge were designated as the first plane, and the plane parallel to the first plane and in contact with the outer surface of the face back was designated as the second plane. When, the distance between the first plane and the second plane is defined as the maximum head width M.
The first plane and the plane parallel to the second plane are set as the central plane at a position halved in the dimension connecting the first plane and the second plane, and the head is located on the face side from the central plane. A plane parallel to the central surface at a position significantly separated by 1/4 of M is defined as a third plane, and parallel to the central surface at a position separated from the central surface by 1/4 of the maximum head width M on the face back side. When the plane to be used is the fourth plane, the cover body is located within the first range partitioned by the third plane and the fourth plane.
The plane parallel to the central surface and passing through the edge of the cover body closest to the face portion is defined as the fifth plane, and the plane parallel to the central surface and passing through the edge portion of the cover body closest to the face back is the fifth plane. When the number of planes is 6, the portion of the inner surface of the cover body facing the space through the opening at a substantially central position of the second range partitioned by the fifth plane and the sixth plane. A rib made of a metal material that supports the space side extends in the toe heel direction so as to cross the opening .
The rib is provided integrally with the head body, and the metal material of the rib is the same as the metal material of the head body.
The rib extends in the toe heel direction and both ends in the extending direction are connected to the edge of the opening.
The rib has a T-shaped cross section, and includes a support wall portion and a reinforcing wall portion.
The support wall portion is formed by superimposing the cover body on the inner surface of the cover body facing the space.
The reinforcing wall portion is located in the center in the width direction orthogonal to the extending direction of the support wall portion, from the inner surface of the support wall portion facing the space to the space side over the entire length of the support wall portion. Protruding,
A golf club head that features that. The toe-heel direction dimension of the portion where the rib supports the cover body is substantially the same as the total length of the toe-heel direction dimension of the cover body.
The golf club head according to claim 1. The rib is formed so as to extend continuously from the inner surface of the cover body to the inner surface of the head body in which the head body faces the space.
The rib is formed so as to extend over 80% or more of the entire circumference of the inner surface of the golf club head including the inner surface of the cover body and the inner surface of the head body.
The golf club head according to claim 1 or 2. In the head body, a boundary portion extending in a band shape over the entire length of the boundary between the crown portion and the side portion is formed.
The boundary portion is formed of a metal material constituting the head body.
The golf club head according to any one of claims 1 to 3, wherein the golf club head is characterized by the above. Of the boundary portion, the portion within the first range is composed of a thick portion formed with a wall thickness larger than the wall thickness of the crown portion and the side portion adjacent to the boundary portion. ,
4. The golf club head according to claim 4. The head mass of the golf club head is 210 g or less.
When the magnitude of the moment of inertia with the vertical straight line passing through the center of gravity of the golf club head and orthogonal to the horizontal plane as the rotation axis in the reference state is defined as the moment of inertia MI (g · cm ² ), the moment of inertia MI is 6200 g · cm ² or less,
The golf club head according to any one of claims 1 to 5, characterized in that. The head volume of the golf club head is 500 cc or less.
The maximum head width M is 130 mm or less.
The golf club head according to any one of claims 1 to 6, characterized in that. At least one of the portion of the head body located in the third range partitioned by the first plane and the third plane and the portion located in the fourth range from the fourth plane to the face back. A large specific gravity portion formed of a material having a specific gravity larger than that of the portion located in the first range is provided in the portion.
The golf club head according to any one of claims 1 to 7, wherein the golf club head is characterized. A face portion having a vertical height and extending to the left and right, a crown portion extending rearward from the upper part of the face portion, a sole portion extending rearward from the lower portion of the face portion, and the crown portion. A hollow head in which a metal material is formed between the sole portion and a side portion extending between the toe side edge and the heel side edge of the face portion through a face back, and the inside thereof is a space. With the main body
A cover body made of a fiber-reinforced resin material that closes openings formed at at least one of the crown portion, the side portion, and the sole portion from the outside of the head body.
A hollow golf club head equipped with
In a reference state in which the golf club head is installed according to a predetermined lie angle and loft angle with respect to the horizontal plane, the head body is broken at a plane including a normal passing through the center point of the face surface and orthogonal to the horizontal plane. The cross section is used as the face center reference cross section.
In the reference state, the horizontal plane and the plane orthogonal to the face center reference cross section and in contact with the leading edge were designated as the first plane, and the plane parallel to the first plane and in contact with the outer surface of the face back was designated as the second plane. When, the distance between the first plane and the second plane is defined as the maximum head width M.
The first plane and the plane parallel to the second plane are set as the central plane at a position halved in the dimension connecting the first plane and the second plane, and the head is located on the face side from the central plane. A plane parallel to the central surface at a position significantly separated by 1/4 of M is defined as a third plane, and parallel to the central surface at a position separated from the central surface by 1/4 of the maximum head width M on the face back side. When the plane to be used is the fourth plane, the cover body is located within the first range partitioned by the third plane and the fourth plane.
A large specific gravity portion formed of a material having a specific gravity larger than the specific gravity of the remaining portion excluding the fourth range is provided in a portion of the head body located in the fourth range from the fourth plane to the face back. Provide,
The specific gravity of the portion of the head body located in the fourth range is defined as the rear specific gravity Ga.
The specific gravity of the portion of the head body located in the third range partitioned by the first plane and the third plane is defined as the front specific gravity Gb.
When the specific gravity of the portion of the head body located in the first range is the intermediate specific gravity Gc,
The following equation (1) is satisfied,
A golf club head that features that.
Ga>Gb> Gc …… (1)

Images