GOLF CLUB HEAD

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a golf club head and, more particularly, to a vibration suppression technique at the time of impact.

2. Description of the Related Art

To improve an impact feel and an impact sound, a golf club head equipped with an damping member which suppresses its vibration at the time of impact has been proposed. Japanese Utility Model Laid-Open No. 6-26927, for example, discloses a golf club head provided with a sheet or coating with antivibration performance, and shows synthetic rubber as an example of the material of the sheet.

When a resin material such as synthetic rubber is used as the damping member, it is often impossible to effectively suppress high-frequency vibration. Also, in the golf club head, the installation space of an damping member is not always large, or the weight of the golf club head increases when a large number of damping members are used. Therefore, the damping member is preferably as small as possible.

SUMMARY OF THE INVENTION

It is an object of the present invention to improve the antivibration performance at the time of impact.

According to an aspect of the present invention, there is provided a golf club head to which an damping member is attached, wherein the damping member is formed by combining a plurality of materials including at least a resin material and a damping alloy.

According to another aspect of the present invention, there is provided a golf club head to which an damping member is attached, wherein the damping member being formed by combining a plurality of materials including at least a resin material and a magnetic material.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external view of a golf club head according to an embodiment of the present invention;

FIG. 2A is a sectional view taken alone a line I-I in FIG. 1;

FIG. 2B is a partial enlarged view of the sectional view shown in FIG. 2A;

FIG. 3 is an exploded perspective view of the golf club head shown in FIG. 1;

FIG. 4A is an external view of the head body;

FIGS. 4B and 4C are views showing other embodiments of an damping member;

FIG. 5 is an external view of a golf club head according to another embodiment of the present invention;

FIG. 6 is an external view of the golf club head, shown in FIG. 5, when viewed from another direction;

FIG. 7 is an exploded perspective view of an damping member;

FIG. 8A is a sectional end elevational view of a damping alloy taken along a line II-II in FIG. 7;

FIG. 8B is a sectional end elevational view of a resin material taken along the line II-II in FIG. 7;

FIG. 8C is a sectional view of the damping member taken along a cross-section corresponding to the line II-II in FIG. 7; and

FIG. 8D is a view for explaining another example of the resin material.

DESCRIPTION OF THE EMBODIMENTS
First Embodiment

FIG. 1 is an external view of an iron golf club head 1 according to the first embodiment of the present invention and, more specifically, a perspective view of the golf club head 1 when viewed from the side of a face portion. Although an example in which the present invention is applied to an iron golf club head will be given herein, the present invention is also applicable to wood and utility (hybrid) golf club heads.

The golf club head 1 includes a face portion (striking surface) 2, sole portion 3, and hosel portion 4. A shaft (not shown) is attached to the hosel portion 4. A plurality of scorelines 2a are formed in the face portion 2. The scorelines 2a are parallel linear grooves extending in the toe-to-heel direction.

The golf club head 1 includes a head body 10 and a face member 20 fixed to the head body 10. FIG. 2A is a sectional view taken along a line I-I in FIG. 1, FIG. 2B is a partial enlarged view, FIG. 3 is an exploded perspective view of the golf club head 1, and FIG. 4A is an external view of the head body 10 when viewed from the side of the face portion 2.

The face member 20 includes a face forming portion 21, and a front portion forming portion 22 extending from the lower end portion of the face forming portion 21 to the back side. The face forming portion 21 has a front surface which forms the face portion 2. The front portion forming portion 22 forms a front portion 3a of the sole portion 3 (its portion on the side of the face portion 2).

The face member 20 is formed by a metal material such as a titanium alloy, stainless steel, maraging steel, or a steel alloy. The face member 20 can be formed by, for example, casting, forging, or press forging in which a plate member is pressed and molded. Forging is advantageous in terms of ease in forming a complex shape.

The head body 10 includes the hosel portion 4. The head body 10 also includes an opening portion 10a through which the back surface of the face member 20 (a back surface 21a of the face forming portion 21) is exposed to the back side. The opening portion 10a is defined by a peripheral edge portion 11.

The peripheral edge portion 11 includes an upper portion forming portion 12, toe-side side forming portion 13, sole forming portion 14, and heel-side side forming portion 15. The side forming portion 13 forms the toe-side side portion of the golf club head 1, and includes an end surface 13F on the side of the face portion 2. The end surface 13F is divided into an outer region 13Fa and an inner region 13Fb on the side of the sole portion 3. The inner region 13Fb is recessed more to the back side than the outer region 13Fa.

The sole forming portion 14 forms the sole portion 3 other than the front portion 3a, and includes an end surface 14a on the side of the face portion 2. A weight member 16 for barycentric position adjustment is fixed to the sole forming portion 14. The weight member 16 is fixed to the recessed portion formed in the sole forming portion 14. The weight member 16 is formed by, for example, a metal material different from that of the head body 10.

In the face member 20, the back surface 21a of the face forming portion 21 is fixed to the outer region 13Fa and the end surface of the upper portion forming portion 12 on the side of the face portion 2, and an end surface 22a of the front portion forming portion 22 on the back side is fixed to the lower portion of the end surface 14a. The head body 10 and the face member 20 are fixed to each other by, for example, welding. The inner region 13Fb and the upper portion of the end surface 14a are spaced apart from the back surface 21a of the face forming portion 21.

The sole forming portion 14 is thicker than the front portion forming portion 22, as shown in FIG. 2A. Making the sole forming portion 14 relatively thick improves the rigidity and lowers the center of gravity of the golf club head. Also, making the entire face portion 2 including the front portion forming portion 22 relatively thin allows the face forming portion 21 to easily flex at the time of impact.

In this embodiment, a gap is formed between the face forming portion 21 and the end surface 14a of the sole forming portion 14 by providing the front portion forming portion 22. With this arrangement, the lower portion of the face forming portion 21 can easily flex. It is therefore possible to suppress a decrease in flight distance when a golf ball is struck by the lower portion of the face portion 2.

An damping member 30 is attached in the gap between the face forming portion 21 and the end surface 14a of the sole forming portion 14. The damping member 30 is fixed to this gap by, for example, an adhesive. The damping member 30 is formed by combining a resin material 31 and a damping alloy 32 to constitute a stacked body in this embodiment. The resin material 31 is in contact with the back surface 21a of the face forming portion 21, and the damping alloy 32 is in contact with the end surface 14a of the sole forming portion 14.

The resin material 31 is made of, for example, a synthetic resin material or a natural resin material (for example, natural rubber). The resin material 31 is preferably made of an elastic body (especially a viscoelastic body), and is, for example, NBR (acrylonitrile butadiene rubber). Examples of the damping alloy 32 are flake graphite cast iron, a magnesium alloy, Silentalloy (Fe—Cr—Al), an Ni—Ti alloy, and an Mn—Cu alloy.

In this embodiment, the damping alloy 32 is a plate member, which is fixed to the resin material 31 by, for example, an adhesive on its back side. As the damping alloy 32 is stacked on the resin material 31 as a plate member, the rigidity of the damping member 30 can be improved even if a soft resin material is adopted as the resin material 31. This makes it easy to deal with the damping member 30 in assembling it into the golf club head 1.

In this embodiment, as described above, the lower portion of the face forming portion 21 can easily flex, but an impact feel or an impact sound often deteriorates as the amount of flexure increases. However, the damping member 30 facilitates vibration damping. In this way, in this embodiment, an impact feel and an impact sound can be improved while allowing the lower portion of the face portion 2 to easily flex.

Especially because the damping member 30 is formed by combining the resin material 31 and the damping alloy 32, the damping alloy 32 can suppress vibration with relatively high frequencies, and the resin material 31 can suppress vibration with relatively low frequencies, thus widening the vibration suppression frequency range. This makes it possible to improve the antivibration performance at the time of impact.

Also, in this embodiment, the damping member 30 is formed in an L shape, and extends to the gap between the inner region 13Fb and the back surface 21a of the face forming portion 21. This makes it possible to prevent an impact feel from deteriorating even if a golf ball is struck by a portion on the toe side away from the sweet spot of the face portion 2.

Although the damping member 30 is formed by combining two materials: the resin material 31 and the damping alloy 32 in this embodiment, it may be formed by combining three or more materials. For example, the resin material 31 may be mixed with a metal powder for weight adjustment, or fine particles of an inorganic material for improving the vibration energy absorption performance. Examples of the inorganic material are mica, glass, and calcium carbonate.

Various methods can be adopted to combine the resin material 31 and damping alloy 32. For example, the arrangement of the resin material 31 and damping alloy 32 may be reversed. This means that the damping alloy 32 may be disposed on the side of the back surface 21a of the face forming portion 21, while the resin material 31 is disposed on the side of the end surface 14a of the sole forming portion 14. Also, a stacked body may be formed by sandwiching the resin material 31 using a pair of plate members 32 made of a damping alloy, as shown in FIG. 4B. This arrangement makes it easier to deal with the damping member 30 in assembling it into the golf club head 1. In contrast to an example illustrated in FIG. 4B, a stacked body may be formed by sandwiching one damping alloy 32 using two resin materials 31.

Instead of the method of stacking the resin material 31 and damping alloy 32, the damping member 30 may be a mixture of the resin material 31 with small pieces 32′ of a damping alloy, as shown in FIG. 4C. The small pieces 32′ can have various shapes such as a plate, spherical, or rod shape. Also, the damping member 30 may be a mixture of the resin material 31 with fine particles of a damping alloy.

Second Embodiment

FIGS. 5 and 6 are perspective views of a golf club head 110 according to another embodiment of the present invention, in which FIG. 5 is a perspective view of the golf club head 110 when viewed from above; and FIG. 6 is a perspective view of the golf club head 110 when viewed from below. Although an example in which the present invention is applied to a wood golf club head will be given herein, the present invention is also applicable to iron and utility (hybrid) golf club heads.

The golf club head 110 takes the form of a hollow body, and its peripheral wall forms a face portion 111, a crown portion 112, a sole portion 113, and a side portion 114. The face portion 111 forms a face surface (striking surface). The crown portion 112 forms the upper portion of the golf club head 110. The sole portion 113 forms the bottom portion of the golf club head 110. The side portion 114 forms the side portion of the golf club head 110. The side portion 114 includes toe-, back-, and heel-side portions. The golf club head 110 also includes a hosel portion 115 to which a shaft is attached.

The golf club head 110 can be made of a metal material such as a titanium-based metal (for example, 6Al-4V-Ti titanium alloy), stainless steel, or a copper alloy such as beryllium copper.

An damping member 120 is fixed to the golf club head 110, as shown in FIG. 6. Although the damping member 120 is fixed to the heel-side portion of the side portion 114 in this embodiment, the fixing portion is not limited to this, and may be, for example, the crown portion 112 or sole portion 113. In this embodiment, the damping member 120 is separably fixed to the golf club head 110 using a bolt 124. However, the fixing method is not limited to this, and may be adhesion or sticking.

The damping member 120 not only suppresses vibration of the golf club head 110 at the time of impact, but also functions as an ornament which improves the external appearance of the golf club head 110.

FIG. 7 is an exploded perspective view of the damping member 120. The damping member 120 is formed by adhering a shell-shaped damping alloy 121 and a resin material 122 to each other. FIG. 8A is a sectional end elevational view of the damping alloy 121 taken along a line II-II in FIG. 7, FIG. 8B is a sectional end elevational view of the resin material 122 taken along the line II-II in FIG. 7, and FIG. 8C is a sectional view of the damping member 120 taken along a cross-section corresponding to the line II-II in FIG. 7.

The damping alloy 121 is formed in a cup shape which opens on the side of mounting on the golf club head 110. Practical examples of the damping alloy 121 are the same as those of the damping alloy 32.

In this embodiment, a plurality of linear grooves 121a′ are formed in an outer surface 121a of the damping alloy 121 to improve the aesthetic design features of the golf club head 110. An aesthetic design pattern represented not only by such a graphics but also by a text and a color can be formed on the outer surface 121a of the damping alloy 121. Such an aesthetic design pattern may be printed on the outer surface 121a.

A circular recessed portion 1211 is formed at the central portion of the outer surface 121a of the damping alloy 121, and a through hole 1212 into which the bolt 124 is to be inserted is formed at the center of the recessed portion 1211. The recessed portion 1211 at least partially accommodates the head of the bolt 124.

The resin material 122 is a solid material which fills the interior of the damping alloy 121, and is made of, for example, a resin block having a specific shape formed by molding in advance. Examples of the resin material 122 are the same as those of the resin material 31.

The resin material 122 has an adhesive surface 122a, and a mounting surface 122b to be fitted in the golf club head 110.

The adhesive surface 122a is a portion adhered to an inner surface 121b of the damping alloy 121 by an adhesive layer 123, and has an outer shape roughly conforming to the shape of the inner surface 121b. In this embodiment, since the adhesive layer 123 is formed over the entire region on the adhesive surface 122a, the outer shape of the adhesive surface 122a is slightly smaller than the shape of the inner surface 121b of the damping alloy 121.

Further, a slightly recessed, separated portion 1220 is formed in the portion of the adhesive surface 122a, which is located behind the surface of the damping alloy 121, in which the grooves 121a′ are formed. The separated portion 1220 is more considerably separated from the inner surface 121b of the damping alloy 121 than from the remaining portion of the adhesive surface 122a. The adhesive layer 123 can be relatively thick in the separated portion 1220.

A circular recessed portion 1221 is formed at the central portion of the separated portion 1220, and a through hole 1222 into which the bolt 124 is to be inserted is formed at the center of the recessed portion 1221. The recessed portion 1221 partially accommodates the recessed portion 1211 in the damping alloy 121.

In this embodiment, the mounting surface 122b has an outer shape roughly conforming to that of the golf club head 110. In this embodiment, since the damping member 120 is fastened to the golf club head 110 using the bolt 124 as a method of fixing the damping member 120 to the golf club head 110, the mounting surface 122b comes into contact (especially, press contact) with the surface of the golf club head 110. If adhesion or sticking is selected as the fixing method, an adhesive or a sticker is interposed between the mounting surface 122b and the surface of the golf club head 110.

The adhesive layer 123 adheres the inner surface 121b of the damping alloy 121 to the adhesive surface 122a of the resin material 122. The adhesive layer 123 is formed by, for example, supplying a liquid adhesive to the gap between the inner surface 121b of the damping alloy 121 and the adhesive surface 122a of the resin material 122, and hardening the adhesive. As the adhesive which forms the adhesive layer 123, a synthetic adhesive such as an epoxy resin adhesive or an acrylic adhesive is preferable. Especially the use of an adhesive, that has a hardness higher than the resin material 122 after hardening, makes it possible to reinforce the damping alloy 121 and, more specifically, reinforce the surface portion of the damping alloy 121, in which the grooves 121a′ are formed, by the adhesive layer 123 formed in the separated portion 1220.

After the damping alloy 121 is adhered to the resin material 122, the bolt 124 is inserted into the holes 1212 and 1222 and screwed into a screw hole 114a (FIG. 7) formed in the golf club head 110, thereby fixing the damping member 120 to the golf club head 110.

In this embodiment, since the damping member 120 is formed by combining the resin material 122 and the damping alloy 121, the damping alloy 121 can suppress vibration with relatively high frequencies, and the resin material 122 can suppress vibration with relatively low frequencies, thus widening the vibration suppression frequency range. This makes it possible to improve the antivibration performance at the time of impact.

Also, since the solid resin material 122 fills the interior of the damping alloy 121 and forms the mounting surface 122b, the mounting surface 122b to be fitted in the golf club head 110 can be formed. This makes it possible not only to stably fix the damping member 120 to the golf club head 110, but also to transmit vibration of the golf club head 110 to the damping member 120.

Since the damping alloy 121 is adhered to the resin material 122 by the adhesive layer 123, their adhesion strength can be improved. This contributes to tightly fixing the damping alloy 121 and resin material 122 to each other.

Also, since the resin material 122 forms the mounting surface 122b, and the damping member 120 is fixed to the golf club head 110 by fastening using the bolt 124, the damping member 120 can be more reliably fitted in and fixed to the golf club head 110 by elastic deformation of the resin material 122. Moreover, a plurality of types of damping members 120 having different design patterns and weights can be prepared and selected by the user.

Moreover, the resin material 122 may be mixed with small pieces 125, as shown in FIG. 8D. The small pieces 125 can have various shapes such as a plate, spherical, or rod shape. The resin material 122 may be mixed with fine particles of a damping alloy in place of small pieces 125. In these cases, the damping alloy 121 may be an aluminum alloy or a nickel alloy.

Third Embodiment

Although an damping member formed by combining a resin material and a damping alloy has been described in the above-mentioned first and second embodiments, a magnetic material may be used in place of a damping alloy. The magnetic material is, for example, ferrite such as barium ferrite or strontium ferrite, or a rare-earth magnet such as a samarium-cobalt magnet or a neodymium-iron-boron magnet, and need only have a magnetic force.

In this case, the mounting portion of the damping member is a portion, made of a magnetic material (for example, soft iron), of the golf club head. Therefore, the resin material of the damping member is at least partially sandwiched between the golf club head and the magnetic material of the damping member, and a magnetic force acts in its compression direction. This prompts conversion of vibration energy into thermal energy inside the resin material, thus improving the vibration suppression effect provided by the resin material. This makes it possible to obtain a greater vibration suppression effect using a smaller damping member, thus improving the antivibration performance at the time of impact.

As a practical arrangement example, an arrangement in which the portion made of the damping alloy is replaced with a magnetic material can be adopted in the above-mentioned first and second embodiments. That is, it is possible to adopt an arrangement in which the damping alloy 32 shown in FIGS. 2A and 2B or 4B is replaced with a magnetic material, or an arrangement in which the small pieces 32′ of the damping alloy shown in FIG. 4C are replaced with a magnetic material. It is also possible to adopt a mixture of a resin material with fine particles of a magnetic material, as a matter of course. It is moreover possible to adopt an arrangement in which the damping alloy 121 shown in FIG. 7 is replaced with a magnetic material.

It is again possible to adopt an damping member formed by combining three materials: a damping alloy, a magnetic material, and a resin material. In an example shown in FIGS. 2A and 2B or 7, the damping alloy 32 or 121 can be directly adopted to form an arrangement in which small pieces or fine particles of a magnetic material are mixed in the resin material 31 or 122. This makes it possible not only to widen the vibration suppression frequency range, but also to improve the vibration suppression effect by the resin material.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2012-020300, filed Feb. 1, 2012, which is hereby incorporated by reference herein in its entirety.

GOLF CLUB HEAD

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CPC

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Abstract

Description

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Priority Claims (1)