JP5952655B2 - Golf club head and manufacturing method thereof - Google Patents

Description

  The present invention relates to a golf club head that can realize high hitting sound, improved directional stability of the hit ball, and improved durability, and a method of manufacturing the same.

  The following Patent Document 1 is composed of a head body made of a metal material and provided with openings in the crown part, side part and sole part, and three cover members made of fiber reinforced resin and closing the openings. A golf club head is described.

  However, the golf club head of Patent Document 1 has problems that the hitting sound is low and the hitting feeling is poor because the cover members are independent (separated). Further, the golf club head of Patent Document 1 has a problem that the bonding strength between the cover member and the head body is low.

  Japanese Patent Application Laid-Open No. 2004-259542 discloses a golf body in which a main body made of a metal material and integrally including a face portion and a sole portion and a cover portion made of a fiber reinforced resin and integrally including a crown portion and a side portion are fixed. The club head is listed.

  However, in the golf club head of Patent Document 2, since all of the side portions are formed of fiber reinforced resin having a small specific gravity, the moment of inertia around the vertical axis passing through the center of gravity of the head is reduced. For this reason, the golf club head of Patent Document 2 has a problem that the directionality of the hit ball is not stable.

  Patent Document 3 listed below describes a golf club head composed of a face member made of a metal material and an aft body made of a fiber reinforced resin and constituting the back of the head of the face member. However, the golf club head of Patent Document 3 also has a problem that the moment of inertia around the vertical axis passing through the center of gravity of the head is small and the directionality of the hit ball is not stable.

  The following Patent Document 4 includes a metal material member made of a metal material and having an opening formed between the crown portion and the side portion, and a resin member made of a fiber reinforced resin and constituting the entire crown portion. A golf club head is described. However, the golf club head of Patent Document 4 has a problem in that the direction of the hit ball is not stable because the crown part is entirely formed of fiber reinforced resin, and the moment of inertia about the vertical axis passing through the center of gravity of the head is small. It was.

  Patent Document 5 listed below describes a golf club head made up of a head body made of a metal material and having an opening at the crown, and a cover member made of fiber-reinforced resin and closing the openings. ing. However, the golf club head of Patent Document 5 has a problem that the hitting sound is low.

  Patent Document 6 listed below describes a golf club head having a metal face plate and a fiber-reinforced resin crown or sole. However, in the head of Patent Document 6, the crown side edge where the crown portion and the side portion of the head intersect is formed of fiber reinforced resin. For this reason, the head of Patent Document 6 has a problem that the moment of inertia around the vertical axis passing through the center of gravity of the head is small. Moreover, in patent document 6, since the whole area | region of the crown part was formed with the fiber reinforced resin, there existed a problem that a crown part was easy to vibrate at the time of hitting, and the hitting sound was low and small.

Japanese Patent No. 4410606 JP 2001-340499 A US Patent Application Publication No. 2001-0055995 JP 2003-320060 A Japanese Patent No. 3885023 JP-A-2005-296609

  The present invention has been devised to solve the above-mentioned drawbacks of the prior art, and provides a golf club head capable of realizing high hitting sound, improved directional stability of the hit ball, and improved durability. This is the main purpose.

  According to the first aspect of the present invention, a face portion having a face for hitting a ball, a crown portion connected to the upper edge of the face and forming the upper surface of the head, and a bottom surface of the head connected to the lower edge of the face are formed. A sole portion; and a side portion extending between the crown portion and the sole portion from the toe side edge of the face through the rear of the head to the heel side edge of the face, and a hollow portion is provided therein. A golf club head, comprising: a head body made of a metal material and including at least a part of the crown part and at least a part of the side part; and a cover body made of a fiber reinforced resin. A crown opening that opens at the crown, a side opening that opens at the side, and a club that intersects the crown and the side. The cover body includes a crown cover that closes the crown opening, a side cover that closes the side opening, and the hollow body side of the head body. The crown cover and the joint portion connecting the side cover are integrally formed.

  According to a second aspect of the present invention, in the golf club head according to the first aspect, the side opening is disposed on the toe side with respect to the head rearmost portion located most rearward of the head.

  According to a third aspect of the present invention, the side opening is disposed on the heel side of the toe side opening and the toe side opening that is disposed on the toe side relative to the head rearmost part located at the rearmost position of the head. The golf club head according to claim 1, further comprising a heel side opening.

  The invention according to claim 4 is the golf club head according to any one of claims 1 to 3, wherein the joint portion has a receiving portion that contacts the crown side edge portion.

  According to a fifth aspect of the present invention, the area of the crown opening is the contour of the golf club head in a plan view in a reference state where the golf club head is grounded to a horizontal plane while being held at a specified lie angle and loft angle. 5. The golf club head according to claim 1, wherein the golf club head is 60% or more and 85% or less of a planar projection area surrounded by the line.

  According to a sixth aspect of the present invention, there is provided the golf club head manufacturing method according to any one of the first to fifth aspects, wherein at least one prepreg sheet forming the cover body is disposed on the head body. An affixing step of affixing across the crown opening and the side opening from the hollow part side, and heating the head body to which the prepreg sheet is affixed in a cavity of a mold, and the head body And a fixing step of forming the prepreg sheet and fixing the bladder to the periphery of the crown opening and the side opening by expanding a bladder inserted into the hollow portion.

  The golf club head of the present invention includes a head body made of a metal material and having at least a part of a crown part and at least a part of a side part, and a cover body made of a fiber reinforced resin. The head body includes a crown opening that opens at the crown, a side opening that opens at the side, and a crown side edge that includes a crown side edge that intersects the crown and the side. . Such a head body has a large moment of inertia about the vertical axis passing through the center of gravity of the head. Therefore, in the golf club head of the present invention, the directionality of the hit ball is stable.

  In the cover body, a crown cover that closes the crown opening, a side cover that closes the side opening, and a joint that connects the crown cover and the side cover on the hollow portion side of the head body are integrated. Molded.

  Such a cover body contributes to mass reduction of the head. The reduced mass can be used for increasing the head volume and designing the weight distribution. In the cover body, the crown cover and the side cover are connected by a joint portion. Such a cover body is high in rigidity and increases the hitting sound. In addition, the cover body with high rigidity is prevented from being deformed when hit. Thereby, the adhesive strength between the cover body and the opening is maintained high, and the durability is improved.

  As described above, the golf club head of the present invention can achieve high hitting sound, improved directional stability of the hit ball, and improved durability.

1 is a perspective view of a golf club head according to an embodiment of the present invention. FIG. 2 is a plan view of the golf club head of FIG. 1 in a reference state. FIG. 3 is a bottom view of the golf club head of FIG. 2. FIG. 3 is a side view of the golf club head of FIG. 2 viewed from the toe side. FIG. 3 is a rear view of the golf club head of FIG. 2. FIG. 2 is an exploded perspective view of the golf club head of FIG. 1. FIG. 3 is a partial cross-sectional view taken along line AA in FIG. 2. (A) is sectional drawing explaining the internal-pressure shaping | molding method before bladder expansion | swelling, (b) is sectional drawing explaining the internal-pressure shaping | molding method after bladder expansion | swelling. It is a rear view of the golf club head of other embodiments of the present invention. FIG. 3 is a partial cross-sectional view of the golf club head of Example 1 corresponding to the AA portion of FIG. 2. 10 is an exploded perspective view of a golf club head showing a comparative example 2. FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIGS. 1 to 5 show views of a golf club head (hereinafter, simply referred to as “head”) 1 of this embodiment as seen from different directions. 2 to 5 show the reference state of the head 1.

  As shown in FIGS. 2 to 5, the reference state of the head 1 is that the shaft axis center line CL is arranged in an arbitrary vertical plane VP and is tilted at a specified lie angle α and the face 2 is held at the loft angle β. (The face angle is set to zero) and the head 1 is placed on the horizontal plane HP. Unless otherwise stated, it is assumed that the club head 1 is in this reference state. The loft angle is given as an angle larger than 0 degrees. Further, when a roll is provided on the face 2, the loft angle is determined based on a tangent line passing through the sweet spot SS of the face 2.

  In this specification, the front-rear direction of the head 1 is defined as a direction TH parallel to a normal line N lowered from the center of gravity G of the head to the face 2 in plan view in the reference state, as shown in FIG. The toe-heel direction is a direction TK perpendicular to the normal N in the plan view. Note that the intersection of the normal N and the face 2 is the sweet spot SS.

  As shown in FIG. 1, the head 1 includes a face portion 3, a crown portion 4, a sole portion 5, a side portion 6, and a hosel portion 7.

  The face portion 3 is formed with a face 2 as a surface for hitting a ball on the front surface. The crown portion 4 extends from the upper edge 2a of the face 2 to the rear of the head and forms the upper surface of the head. As shown in FIG. 3, the sole portion 5 extends rearward from the lower edge 2 b of the face 2 to form the bottom surface of the head. As shown in FIGS. 1 and 3, the side portion 6 extends between the crown portion 4 and the sole portion 5 from the toe side edge 2 c of the face 2 to the heel side edge 2 d of the face 2 through the back of the head. .

As shown in FIG. 2, the hosel portion 7 is provided on the heel side of the crown portion 4. The hosel part 7 has a cylindrical shaft insertion hole 7a into which the tip of a golf club shaft (not shown) is inserted. A golf club (not shown) is formed by attaching a golf club shaft to the shaft insertion hole 7a.

  The head 1 of the present embodiment is provided with a hollow portion i (shown in FIG. 6) inside. The head 1 is preferably configured as a wood type. The wood type golf club head includes at least a driver (# 1), a brushy (# 2), a spoon (# 3), a buffy (# 4), a creek (# 5), etc. It is a concept that includes heads having different shapes but having substantially similar shapes.

Although not particularly limited, the volume of the head 1 is preferably 90 cm ³ or more, more preferably 100 cm ³ or more. Such a large volume is useful for deepening the moment of inertia of the head 1 and the center of gravity of the head. On the other hand, even if the volume of the club head 1 is too large, there are problems such as an increase in head weight, deterioration in swing balance, and violation of golf rules. Therefore, the volume V of the head 1 is preferably 460 cm ³ or less, more preferably 430 cm ³ or less.

  If the mass of the head 1 is too small, the kinetic energy of the head becomes small, and there is a tendency that improvement in the flight distance cannot be expected. On the other hand, if the mass of the head 1 is too large, it is difficult to swing the golf club, and the direction stability and the flight distance of the hit ball tend to be deteriorated. From such a viewpoint, the mass of the head 1 is preferably 185 g or more, more preferably 195 g or more, preferably 230 g or less, more preferably 225 g or less.

  As shown in FIGS. 1 and 6, the head 1 includes a head main body 1A made of a metal material, a cover body 1B made of a fiber reinforced resin, and a face base 1C, which are joined together. ing.

  The head main body 1 </ b> A includes, as at least two openings, a crown opening Oc that opens at the crown 4 and a side opening Os that opens at the side 6. The head body 1 </ b> A of the present embodiment is further provided with a face opening Of that opens at the face portion 3. The cover body 1B closes the crown opening Oc and the side opening Os. The face base 1 </ b> C closes the face opening portion Of and constitutes a part of the face portion 3.

  Such a head 1 can be made with a small mass because the crown opening portion Oc and the side opening portion Os are constituted by the cover body 1B having a small specific gravity. Therefore, the head 1 of the present invention can obtain a mass that can be used for increasing the head volume and designing the weight distribution (hereinafter, such a mass is referred to as “excess mass”).

  The head main body 1 </ b> A of the present embodiment constitutes a remaining portion excluding the three openings Oc, Os, and Of from the head 1. That is, the head main body 1A includes a face edge portion 3A, a crown edge portion 4A, a side edge portion 6A, a sole portion 5, and a hosel portion 7, which are integrally formed.

  In order to increase productivity, the head main body 1A is preferably formed of a single cast product (more specifically, a lost wax precision cast product). However, the head main body 1A may be formed by joining two or more parts such as forging, casting, and rolling material.

  The metal material forming the head main body 1A is not particularly limited, but preferably stainless steel, maraging steel, pure titanium, aluminum alloy, magnesium alloy, titanium alloy, or the like is used.

  The face edge 3 </ b> A of the head main body 1 </ b> A constitutes around the face opening Of in the face 3. In the present embodiment, the face opening Of is formed without protruding from the face 3. When the head 1 in the reference state is viewed from the front, the face opening portion Of surrounds the sweet spot SS and has a smooth outline along the outline of the face 2. For this reason, the face edge 3A of the present embodiment is continuously formed in an annular shape around the face opening Of. The face opening Of may be provided with a plurality of claw pieces K that can hold the back surface of the face base 1C.

  The crown edge 4 </ b> A of the head main body 1 </ b> A constitutes the crown opening 4 around the crown opening Oc. In this embodiment, the crown opening Oc is formed without protruding from the crown portion 4. For this reason, the crown edge portion 4A is also continuously formed in an annular shape around the crown opening portion Oc. The crown edge 4A is connected to the face edge 3A at the upper edge 2a of the face 2. Note that the contour of the crown opening portion Oc is formed by a smooth curve along the contour of the crown portion 4 except for the heel side. This is useful for preventing stress concentration and the like.

  By increasing the crown opening Oc, the mass of the upper portion of the head can be reduced, and the center of gravity of the head 1 can be lowered. As shown in FIG. 2, the crown opening Oc is an opening including the center of gravity G of the head in a plan view of the head 1 in the reference state. Such an opening acquires excess mass while reducing more mass from near the center of gravity G of the head. By using this surplus mass in the peripheral portion of the head, the moment of inertia Ma about the vertical axis passing through the center of gravity G of the head increases.

  In a plan view of the reference state, the area Sa of the crown opening Oc is preferably 60% or more, more preferably 63% or more of the planar projection area S surrounded by the contour line R of the head 1. This reliably lowers the center of gravity of the head 1 and further increases the moment of inertia Ma.

  As shown in FIGS. 3, 4, and 6, the side edge 6 </ b> A configures the side opening 6 around the side opening Os. The side opening Os of the present embodiment is housed on the toe side of the head rearmost portion Ba located at the rearmost side of the head 1 in a bottom view (FIG. 3) in the reference state. The side opening Os is provided at a distance from the toe side edge 2c of the face 2 to the rear of the head. Accordingly, the side edge portion 6A of the present embodiment forms the entire side portion 6 in the heel side region from the head last portion Ba, and the side portion 6 in the side portion 6 in the toe side region from the head last portion Ba. The periphery of the opening Os is formed.

  By arranging the side opening Os close to the toe side, the mass on the toe side of the head 1 is reduced, and the center of gravity G of the head is arranged on the heel side. Such a head 1 is easy to return to the state in which the face 2 is addressed at the time of swing, and the direction stability of the hit ball is improved. As shown in FIG. 3, the distance La in the head longitudinal direction between the centroid Zs of the side opening Os and the toe side end T located closest to the toe side of the head 1 in the bottom view of the head 1 in the reference state. Is 20% or less of the head length L, more preferably 10% or less. Thereby, the said effect | action is exhibited more reliably. The “head length” is a distance in the front-rear direction between the leading edge FE located on the foremost side of the head 1 and the head rearmost portion Ba.

  As shown in FIG. 3, in the bottom view of the head 1 in the reference state, the area Sb of the side opening Os is preferably 4% or more, more preferably 6% or more of the planar projection area S, preferably It is 20% or less, more preferably 18% or less. When the area Sb of the side opening Os is increased, the rigidity of the head 1 may be reduced. On the contrary, when the area Sb of the side opening Os is small, there is a possibility that a sufficient excess mass cannot be obtained from the side 6.

  The side edge 6A and the crown edge 4A are integrally connected by a crown side edge 8. Thereby, the crown side edge portion 9 is formed in the head main body 1A. The crown side edge 8 constitutes the contour line R of the head 1 in a plan view (FIG. 2) in the reference state.

The crown side edge portion 9 includes a crown side edge 8 and has a width from the crown side edge 8 toward the crown portion 4 side and the side portion 6 side. The crown side edge portion 9 is located on the outermost side of the head 1 and continuously extends around the head center of gravity G from the toe side edge 2c to the heel side edge 2d in an arc shape. Such a crown side edge portion 9 distributes more mass at a position away from the center of gravity G of the head. Therefore, in the head 1 of this embodiment, the moment of inertia Ma about the vertical axis passing through the head center of gravity G is increased, and the directional stability of the hit ball is improved.

  The crown opening Oc reduces the mass of the head upper part. However, if the crown opening portion Oc is increased, the mass of the crown / side edge portion 9 occupying the crown portion 4 is decreased, and the moment of inertia Ma may not be sufficiently increased. From such a viewpoint, it is desirable that the area Sa of the crown opening Oc is 85% or less of the planar projection area S of the head 1 in a plan view of the reference state. Thereby, the low center of gravity of the head 1 and the increase of the moment of inertia Ma are balanced.

  Further, when the side opening Os is disposed on the sole 5 side, the head center of gravity G may not be lowered. Conversely, when the side opening Os is disposed on the crown 4 side, the mass of the crown / side edge 9 is increased. The moment of inertia Ma may be reduced. For this reason, in a side view of the head 1 in the reference state, the vertical distance He between the lowermost end Se of the side opening Os and the horizontal plane HP is preferably a vertical distance from the horizontal plane HP to the highest point Pa of the crown portion 4. It is 7.5% or more of the head height H, more preferably 10% or more, and preferably 30% or less, more preferably 25% or less. Similarly, in a side view of the head 1 in the reference state, the vertical distance Hi between the uppermost end Si of the side opening Os and the horizontal plane HP is preferably 40% or more, more preferably 45% or more of the head height H. , Preferably 75% or less, more preferably 70% or less.

  As shown in FIG. 6, the cover body 1B integrally includes a crown cover 11 that closes the crown opening portion Oc, a side cover 12 that closes the side opening portion Os, and a joint portion 13 that connects these at the hollow portion i side. It has. Such a cover body 1 </ b> B has increased rigidity due to the joint portion 13, and vibration and deformation at the time of impact are suppressed. Therefore, the head 1 of this embodiment has a high hitting sound. In the head 1 of this embodiment, the adhesive strength between the cover body 1B, the crown opening portion Oc, and the side opening portion Os is maintained high, and the durability is improved.

  As shown in FIG. 7 which is an AA cross section of FIG. 6 and FIG. 2, the crown cover 11 has a main portion 11 a that forms the outer surface 4 a of the crown portion 4, and is stepped from the periphery of the main portion 11 a. In addition, it includes an overlapping portion 11b that overlaps the inner surface 4b of the crown edge portion 4A.

  Similarly, the side cover 12 includes a main portion 12a that forms the outer surface 6a of the side portion 6, and an overlapping portion 12b that is recessed in a step shape from the periphery of the main portion 12a and overlaps the inner surface 6b of the side edge portion 6A. It is out.

  In the present embodiment, the joint portion 13 is formed by integrally connecting the toe side portion of the overlapping portion 11 b of the crown cover 11 and the crown side portion of the overlapping portion 12 b of the side cover 12.

  The joint portion 13 has a receiving portion 13 </ b> A that contacts the crown side edge portion 9. As shown in FIG. 7, the receiving portion 13 </ b> A has a concave shape along the inner surface of the crown side edge portion 9. Thereby, the crown side edge portion 9 is fitted into the receiving portion 13A, and both are in close contact with each other. Thereby, the cover body 1B is more firmly fixed to the head body 1A.

  In a more preferred embodiment, the receiving portion 13A is bonded to the inner surface of the crown side edge portion 9. In this case, the rigidity of the cover body 1B is further increased, and the head 1 of the present embodiment provides a higher hitting sound. Further, the high rigidity of the cover body 1B further reduces the deformation of the cover body 1B at the time of hitting the ball, and the adhesive strength between the cover body 1B, the crown opening portion Oc and the side opening portion Os is increased, and the durability is improved. improves. Furthermore, since the receiving portion 13A is bonded to the crown / side edge 9, it is possible to suppress chatter noise generated by repeated contact and separation between the receiving portion 13A and the crown / side edge 9 when the ball is hit, The hitting feeling is improved. Note that the receiving portion 13 </ b> A of the present embodiment is formed from the entire region of the joint portion 13. Such receiving portion 13A further improves the durability of the head 1.

  As matrix resin used for the fiber reinforced resin which comprises cover body 1B, a thermosetting resin or a thermoplastic resin is mentioned, for example. Examples of the thermosetting resin include an epoxy resin, an unsaturated polyester resin, a phenol resin, and a polyurethane resin. Examples of the thermoplastic resin include polyamide resin, saturated polyester resin, polystyrene resin, polyethylene resin, AS resin, and polypropylene resin.

  Examples of the reinforcing fibers used in the fiber reinforced resin include inorganic fibers such as carbon fibers, glass fibers, boron fibers, silicon carbide fibers, and alumina fibers, organic fibers such as polyethylene and polyamide, and metal fibers. One or more kinds of these fibers are used as the reinforcing fiber.

  The reinforcing fiber preferably has a tensile elastic modulus of 50 GPa or more, more preferably 100 GPa or more, preferably 450 GPa or less, more preferably 350 GPa or less in order to ensure the durability and tensile strength of the cover body 1B. The tensile modulus of the fiber is a value measured in accordance with “Carbon Fiber Test Method” of JIS R7601.

  As shown in FIG. 6, the face base 1C is formed in a plate shape in this embodiment. The contour shape of the face base 1C is formed to be the same as or slightly smaller than the face opening Of. Thereby, the face base 1 </ b> C forms a main striking surface including the sweet spot SS of the face 2. Such a face substrate 1C is preferably a machined product obtained by accurately finishing a plate material obtained by punching a rolled material by CNC machining.

  Various metal materials are used as the metal material constituting the face base 1C. As this metal material, for example, titanium alloys such as Ti-15V-6Cr-4Al and Ti-6Al-4V having high specific strength, and maraging steel excellent in strength and toughness are desirable.

  Next, a manufacturing method for manufacturing such a head 1 will be described. In this embodiment, the cover body 1B made of fiber reinforced resin is manufactured by an internal pressure molding method in which the molding and the fixing to the head body 1A are performed substantially simultaneously.

  In the manufacturing method of this embodiment, first, the head main body 1A is prepared.

  Next, as shown in FIG. 8A, at least one prepreg sheet P straddling the crown opening Oc and the side opening Os on the inner surface 4b of the crown edge 4A and the inner surface 6b of the side edge 6A. Is pasted (pasting step). In the present embodiment, an adhesive is filled between the prepreg sheet closest to the head outer surface and the inner surfaces 4b and 6b. As a result, the prepreg sheet P is firmly fixed to the head main body 1A, positional displacement is prevented, and molding accuracy is increased. As this adhesive, for example, an epoxy thermosetting adhesive or a primer is preferably employed.

  Next, as shown in FIG. 8B, the head body 1A to which the prepreg sheet P is attached is heated in the cavity 19 of the mold 18 (adhering step). The mold 18 includes, for example, a separable upper mold 18a and lower mold 18b, and a cavity 19 having a desired shape of the head 1 is formed therein.

  In the cavity 19, the prepreg sheet P is in a plastic state that can be deformed by applying sufficient heat. In this state, the bladder B is expanded. The bladder B is inserted into the hollow part i from the face opening part Of, for example. The bladder B has a bag shape made of rubber that can be elastically deformed, and expands by being filled with a high-temperature and high-pressure fluid or steam. Due to the expansion of the bladder B, the prepreg sheet P is compressed by the bladder B and the cavity 19 and formed into the shapes shown in FIGS. 1 to 5 along the shapes of the cavity 19 and the openings Os and Oc.

  When the matrix resin of the prepreg sheet P is completely cured, the bladder B is contracted and taken out from the hollow portion i. The head 1 is taken out from the mold 18.

  As shown in FIG. 8B, when a gap E is formed between the crown edge 4A and side edge 6A of the head body 1A and the cover body 1B, the gap E is bonded to, for example, an adhesive. It is desirable that an agent, a molten metal or a brazing material is filled. Thereby, the outer surface of the head 1 is smoothed, and the head main body 1A and the cover body 1B are firmly fixed.

  Next, the face base 1C as shown in FIG. 6 is fixed to the face edge 3A by, for example, welding.

  The fixing step may be performed after the head body 1A and the face base 1C are fixed. In this case, the bladder B can be inserted from a through hole (not shown) provided in the head body 1A.

  FIG. 9 shows another embodiment of the present invention. In this embodiment, the side opening portion Os is disposed on the heel side with respect to the head rear portion Ba and the toe side side opening portion Os1 disposed on the toe side with respect to the head rearmost portion Ba in the rear view in the reference state. The heel side opening part Os2 is included. In such an embodiment, by dividing the side opening Os into two, each opening can be made smaller than in the case where an opening having the same opening area is formed by one opening, and the side of the head 1 can be reduced. The local rigidity reduction of the part 6 is prevented. Further, by dividing the side opening Os into the toe side and the heel side, the center of gravity depth can be effectively increased by allocating more mass near the head rearmost portion Ba.

  Although the present invention has been described in detail above, the present invention is not limited to the specific embodiments described above, and can be modified in various ways as necessary.

  In order to confirm the effect of the present invention, a wood-type golf club head was prototyped and tested for durability, moment of inertia, and hitting sound (feeling of height, size, reverberation length, etc.).

[Example]
Each head of the embodiment has the basic shape shown in FIGS. As shown in FIG. 10, the head of Example 1 is in a mode in which the receiving portion 13 of the cover body and the inner surface of the crown side edge portion 9 are not in close contact with each other and there is a gap. As shown in FIG. 7, the head of Example 2 is in a form in which the receiving part of the cover body and the crown side edge are in close contact but are not adhered. The heads of the third and subsequent embodiments are the same as those of the second embodiment in which the receiving portion and the crown / side edge are fixed with an adhesive. The main common specifications of each head in the embodiment are as follows.
Head mass: 215 g
Head volume: 170cm ³
Metal material of the head body: Stainless steel Metal material of the face base: Maraging steel Cover body: Five laminates of prepregs in which carbon fibers are aligned in one direction Angle of carbon fibers of the prepreg: 90 with respect to the head longitudinal direction 3 at 0 ° and 2 at 0 ° The distance La / L from the toe side end of the centroid of the side opening: 6.6%
Distance Hi / H at the top end of the side opening: 43.3%
Distance He / H at the lowest end of the side opening: 8.3%

[Comparative Example 1]
The head of Comparative Example 1 was all formed of a metal material, the head volume was 170 cm ³ , and the head mass was 215 g. The external shape of the head of Comparative Example 1 is basically the same as that of the example. Further, the head body of Comparative Example 1 is made of the same stainless steel as that of the example, but does not have a crown opening and a side opening, and a portion corresponding to each opening is formed of stainless steel. The head body of Comparative Example 1 has a face opening as in the example, and a maraging steel face base is fixed thereto.

[Comparative Example 2]
As shown in FIG. 11, the head of Comparative Example 2 is based on the shape and material of Example 1, and includes a stainless steel head body a, a carbon fiber reinforced resin crown cover b, and a carbon fiber reinforced resin side. It is composed of a cover c and a face base d of maraging steel. The crown cover b and the side cover c are separated from each other, and the joint portion of the first embodiment is not provided. The area of each opening in Comparative Example 2 was the same as in Example 1. In order to match the mass with Comparative Example 1, Comparative Example 2 (and each Example) has a larger crown side edge thickness than Comparative Example 1 according to the excess mass obtained at the opening. Yes.
The test method is as follows.

<Durability>
A 42-inch wood type golf club (# 5) was prototyped by attaching FRP shafts (MP700, Flex R, manufactured by Dunlop Sports Co., Ltd.) to each test head. Each club was attached to a swing robot manufactured by Miyamae Co., Ltd., and a commercially available 3-piece golf ball (“XXIO XD” manufactured by Dunlop Sports Co., Ltd.) was repeatedly hit at a face center position at a head speed of 50 m / s. Then, the number of hit balls in which the cover body was damaged was examined. The result is indicated by the actual number of hit balls, and the larger the value, the better the durability. The upper limit hit number of balls was 10,000 times.

<Inertia moment>
In the reference state of the head, the moment of inertia around the vertical axis passing through the center of gravity of the head was measured using MOMENT OF INERTIA MEASURING INSTRUMENT MODEL NO.005-002 manufactured by INERTIA DYNAMICS Inc. The larger the value, the greater the moment of inertia and the better the directionality of the hit ball.

<Hit sound>
Twenty golfers having handicap 5 to 15 hit the golf balls 10 balls at a time using the wood type golf club. At this time, the feeling including the pitch and the magnitude of the hitting sound, the presence / absence of chatter sound, the length of reverberation (which is considered to be more comfortable) was evaluated by the sensuality of the 20 golfers. The result is a 10-point method with 10 points as a perfect score, indicating that the larger the value, the better.
Table 1 shows the test results.

  As a result of the test, it was confirmed that the head of the example improved the durability and the directional stability (moment of inertia) of the hit ball in a well-balanced manner as compared with the head of the comparative example. In addition, it was confirmed that the head of the example had a high hitting sound and a loud sound equivalent to that of the metal head (Comparative Example 1), and a good feeling was obtained.

DESCRIPTION OF SYMBOLS 1 Golf club head 1A Head main body 1B Cover body 2 Face 3 Face part 4 Crown part 6 Side part 8 Crown side edge 9 Crown side edge part 11 Crown cover 12 Side cover 13 Joint part i Hollow part Oc Crown opening part Os Side Aperture

Claims (7)

A face portion having a face for hitting a ball; a crown portion connected to an upper edge of the face and forming a top surface of the head; a sole portion connecting to a lower edge of the face and forming a bottom surface of the head; the crown portion and the sole portion; A golf club head having a side portion extending from the toe side edge of the face to the heel side edge of the face through the back of the head, and having a hollow portion therein,
A head body made of a metal material and including at least a part of the crown part and at least a part of the side part, and a cover body made of a fiber reinforced resin,
The head main body includes a crown opening that opens at the crown, a side opening that opens at the side, and a crown side edge that includes a crown side edge at which the crown and the side intersect. Including
The cover body is integrally formed with a crown cover that closes the crown opening, a side cover that closes the side opening, and a joint that joins the crown cover and the side cover on the hollow portion side of the head body. It is,
In a side view of the golf club head in a reference state,
The vertical distance He between the lowermost end of the side opening and the horizontal plane is 7.5% to 30% of the head height H, which is the vertical distance from the horizontal plane to the highest point of the crown,
A golf club head characterized in that a vertical distance Hi between the uppermost end of the side opening and the horizontal plane is 40% to 75% of the head height H. In the bottom view of the golf club head in the reference state, the distance in the head longitudinal direction between the centroid of the side opening and the toe side end located closest to the toe side of the golf club head is 20% of the head length. The golf club head according to claim 1, wherein: 3. The golf club head according to claim 1, wherein the side opening is disposed on a toe side with respect to a head rearmost portion located most rearward of the head. The side opening includes a toe side opening and a heel side opening that is disposed on the heel side of the head rearmost part, and a heel side side opening disposed on the heel side of the head rearmost part. The golf club head according to claim 1, comprising: The golf club head according to claim 1, wherein the joint portion includes a receiving portion that contacts the crown side edge portion. In a plan view of a reference state in which the golf club head is grounded to a horizontal plane while being held at a specified lie angle and loft angle,
6. The golf club head according to claim 1, wherein an area of the crown opening is 60% or more and 85% or less of a planar projection area surrounded by a contour line of the golf club head. A method for manufacturing a golf club head according to any one of claims 1 to 6,
An attaching step of attaching at least one prepreg sheet forming the cover body across the crown opening and the side opening from the hollow portion side of the head body;
The head body to which the prepreg sheet is attached is heated in a cavity of a mold, and the bladder inserted into the hollow portion of the head body is expanded to form the prepreg sheet and A method of manufacturing a golf club head, comprising: a fixing step of fixing the crown opening and a peripheral edge of the side opening.

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