Patent Application
20200391088
The present invention relates to a golf club head, more particularly to a wall structure of a hollow golf club head.
Japanese Patent Application Publication No. 2003-180885 discloses a hollow golf club head having a cavity therein. This type of golf club head comprises a wall (including, for example, a face portion, a crown wall, a sole wall, etc.) surrounding the cavity.
Reducing the thickness of such wall constituting a hollow golf club head is useful for reducing the mass of the golf club head and as well as designing the mass distribution of the golf club head. For example, by reducing the thickness of the crown wall, it is possible to lower the position of the center of gravity of the head.
On the other hand, such reducing of the wall thickness may reduce the rigidity of the golf club head.
The present invention was therefore, made in view of the above problems, and a primary objective of the present invention is to provide a golf club head in which it is possible to reduce the wall thickness without impairing the rigidity of the head.
According to the present invention, a golf club head has a cavity therein and comprises:
a wall at least a part of which is formed as a patterned convexo-concave wall portion, wherein
the convexo-concave wall portion is composed of convexed portions repeatedly arranged in a first direction and a second direction intersecting the first direction, and concaved portions formed between the convexed portions, and
each of the convexed portions is composed of at least one first protrusion extending in the first direction, and at least one second protrusion extending in the second direction.
The convexo-concave wall portion may constitute a curved portion of the wall which is curved along a curved plane.
The wall provided with the convexo-concave wall portion may be a crown wall of the golf club head forming an upper surface of the golf club head.
As to the overall area of the golf club head measured in the top view of the golf club head under its standard state, the convexo-concave wall portion may occupy an area of from 10% to 95% of the overall area.
The above-said at least one first protrusion may be four first protrusions, and the above-said at least one second protrusion may be four second protrusions.
The above-said at least one first protrusion may be two first protrusions, and the above-said at least one second protrusion may be two second protrusions.
The above-said at least one first protrusion may be one first protrusion, and the above-said at least one second protrusion may be two second protrusions connected to both ends of the one first protrusion.
The concaved portions and the convexed portions may have the same contour shape.
The convexo-concave wall portion may be made of a metal material, and the thickness of the metal material in the convexo-concave wall portion may be in a range from 0.25 to 0.50 mm.
The difference in height between the convexed portions and the concaved portions may be in a range from 0.6 to 4.0 mm.
Each convexed portion may be formed in such a size that a smallest square which circumscribes the convexed portion in the plan view of the convexed portion, has four sides whose length is 10 to 40 mm.
The first direction may be substantially parallel with a front-back direction of the golf club head, and the second direction may be substantially parallel with a toe-heel direction of the golf club head.
In the golf club head according to the present invention, as the wall is provided with the convexo-concave wall portion having the specific configuration, the thickness of the wall can be reduced in the convexo-concave wall portion without impairing its rigidity. Therefore, the golf club head according to the present invention can achieve, for example, mass reduction of the club head and the increased flexibility of designing of the mass distribution.
Embodiments of the present invention will now be described in detail in conjunction with accompanying drawings. In the following descriptions of the respective embodiments, the same or common elements are denoted by the same reference numerals, and redundant descriptions are omitted.
In this application including the description and claims, dimensions, positions, directions and the like relating to the club head refer to those under a standard state of the club head unless otherwise noted.
Here, the standard state of the club head is such that the club head is set on a horizontal plane HP so that the axis CL of the club shaft (not shown) is inclined at the specified lie angle while keeping the axis CL on a vertical plane VP as shown in
[Directions about Head]
Three orthogonal directions relating to the head 1 are defined as follows:
a toe-heel direction y of the head which is parallel with the horizontal plane HP and the vertical plane VP,
a front-back direction x of the head which is parallel with the horizontal plane HP and perpendicular to the vertical plane VP, and an up-down direction z of the head which is orthogonal to both the directions x and y.
In the present embodiment shown in
Wood-type heads include a driver (#1) and a fairway wood. The head 1 may be preferably formed as a driver.
Aside from the wood-type, the head 1 may be formed as a utility type head or an iron type head as long as it has a cavity i.
In the present embodiment, a major part of the head 1 is made of a metal material. As to the metal material, various materials, for example, titanium, titanium alloy, stainless steel, aluminum alloy and the like can be used.
Further, it may be possible that the head 1 is partially made of a nonmetallic material such as resin, rubber, elastomer, fiber reinforced resin or the like.
The head 1 is composed of a face portion 2, and a main body portion 3 extending rearward of the head from the face portion 2.
The face portion 2 in this example is formed in the form of a plate. The front surface of the face portion 2 forms a ball hitting surface 2a. The back surface (not shown) of the face portion 2 faces the internal cavity i.
As shown in
The crown wall 4 is continuous with the face portion 2 and forms the upper surface of the head.
Preferably, the crown wall 4 is smoothly convexly curved as shown in
The sole wall 5 is continuous with the face portion 2 and forms the bottom surface of the head.
In the present embodiment, the sole wall 5 is connected to the crown wall 4 via a smooth curved surface.
However, it may be possible that the main body portion 3 further includes a side wall extending in the up-down direction of the head 1 to connect between the sole wall 5 and the crown wall 4. Thus, the above-said wall further includes the side wall.
Further, the head 1 comprises a hosel portion 6 having the above-said shaft inserting hole 6a into which a golf club shaft (not shown) is fixed.
The center line of the shaft inserting hole 6a corresponds to the axis CL of the inserted club shaft.
The hosel portion 6 in this example has a cylindrical shape and is formed in a heel-side portion of the crown wall 4.
According to the present invention, a convexo-concave wall portion 10 forms at least a part of the above-said wall constituting the head 1.
Here, the wall constituting the head 1 includes the face portion 2, the crown wall 4 and the sole wall 5 in this example, and optionally the above-said side wall.
Preferably, the convexo-concave wall portion 10 is provided in the wall constituting the main body portion 3 of the head 1. In the present embodiment, the convexo-concave wall portion 10 is provided in the crown wall 4.
However, the convexo-concave wall portion 10 may be provided in the sole wall 5 or in the face portion 2.
Further, the convexo-concave wall portion 10 may be provided in two or more of the face portion 2, the crown wall 4 and the sole wall 5, and optional side wall.
As shown, in the convexo-concave wall portion 10, multiple convexed portions 100 are repeatedly arranged in a first direction D1 and a second direction D2 intersecting the first direction D1. And, concaved portions 200 are formed between the convexed portions 100.
Thus, the convexo-concave wall portion 10 has a patterned outer surface, and as can be seen from
Each of the convexed portions 100 is composed of at least one rib-like first protrusion 101 extending in the first direction D1, and at least one rib-like second protrusion 102 extending in the second direction D2 as shown in
As described above, in the convexo-concave wall portion 10 of the present embodiment, the convexed portions 100 are repeatedly arranged in the first direction D1 and the intersecting second direction D2, and the concaved portions 200 are formed between the convexed portions 100. Further, each of the convexed portions 100 comprises at least one rib-like first protrusion 101 extending in the first direction D1 and at least one rib-like second protrusion 102 extending in the second direction D2. As a result, the convexo-concave wall portion 10 is increased in the bending rigidity in the first direction D1 and the second direction D2.
Therefore, in the head 1 according to the present invention, the wall can be reduced in the thickness in the convexo-concave wall portion without reducing the bending rigidity. This facilitates the mass reduction of the head 1 and the designing of the mass distribution, for example.
The mass reduction of the wall can produce a mass margin for increasing the design freedom of the mass distribution of the head 1.
In the case of the convexo-concave wall portion 10 formed as a part of the crown wall 4 as in the present embodiment, by making the convexo-concave wall portion 10 thinner, the mass of the crown wall 4 (namely, the mass of an upper part of the club head) is reduced. This makes it possible to lower the center of gravity of the head 1.
As shown in
Preferably, the first direction D1 is substantially parallel with the front-back direction x of the head, and the second direction D2 is substantially parallel with the toe-heel direction y of the head.
In general, when a golf ball is hit, a large force in the first direction D1 acts on the hitting surface 2a of the face portion 2, and this force is transmitted to the crown wall 4. Therefore, the crown wall 4 undergoes such bending deformation that the crown wall 4 is bent convexly toward the upper side of the head.
However, the convexo-concave wall portion 10 suppresses such bending deformation of the crown wall 4, and thus helps to significantly increase the durability of the crown wall 4 against ball hitting.
In this application including the description and claims, the expression “substantially parallel” means that the angle between the two objects is at most 15 degrees.
Preferably, the convexed portions 100 are each composed of multiple lib-like first protrusions 101 extending in the first direction D1, and multiple lib-like second protrusions 102 extending in the second direction D2.
The four first protrusions 101 extend in parallel with each other, and are displaced from each other in the second direction D2.
The four second protrusions 102 extend in parallel with each other, and are displaced from each other in the first direction D1.
In the convexed portion 100 of the present embodiment shown in
Preferably, one first protrusion 101 and one second protrusion 102 are connected to each other so as to form a corner, thereby forming an L-shaped convex unit 103.
Each convexed portion 100 is made up of four L-shaped convex units 103 which are rotated and arranged around the center C1 of the convexed portion at an angular pitch of 90 degrees. The convexed portion 100 has a swastika-like contour shape.
In
Each concaved portion 200 is composed of at least one first concaved portion 201 extending in the first direction D1, and at least one second concaved portion 202 extending in the second direction D2.
The four first concaved portions 201 extend in parallel with each other, and are displaced from each other in the second direction D2.
The four second concaved portions 202 extend parallel with each other, and are displaced from each other in the first direction D1.
In the concaved portion 200 of the present embodiment shown in
Each concaved portion 200 is made up of four L-shaped concave units 203 which are rotated and arranged around the center C2 of the concaved portion at an angular pitch of 90 degrees. The concaved portion 200 has a swastika-like contour shape.
As is clear from the comparison between
the first concaved portions 201 and the second concaved portions 202 correspond to the first protrusions 101 and the second protrusions 102, respectively.
Here, the contour shape of one convexed portion 100 is that of a most protruding part 100a of the surface of the convexo-concave wall portion 10, and
the contour shape of one concaved portion 200 is that of a most denting part 200a of the surface of the convexo-concave wall portion 10.
By configuring the convexed portions 100 and the concaved portions 200 to have the same contour shape in this way, it becomes possible to eliminate anisotropy at the time of deformation of the convexo-concave wall portion 10. Thereby, the strength of the convexo-concave wall portion 10 can be improved in a well-balanced manner.
As shown in
In this example, the side-wall surface part 300 is an inclined surface, but the side-wall surface part 300 may extend perpendicular to the surface parts 100a and 200a.
In the present embodiment, the convexo-concave wall portion 10 is made of a metal material. As the metal material, various materials, e.g. titanium, titanium alloy, stainless steel, aluminum alloy and the like can be used. In particular, a titanium alloy having a large specific strength is preferable. However, the convexo-concave wall portion 10 may be made of a non-metallic material such as a resin and a fiber reinforced resin.
The convexo-concave wall portion 10 of the present embodiment can be made thinner without losing its rigidity by having the above structure.
The thickness t of the convexo-concave wall portion 10 (metal material thickness t) is preferably set to be at most 1.00 mm, more preferably at most 0.7 mm, still more preferably at most 0.6 mm, yet still more preferably at most 0.5 mm in view of the mass reduction and mass distribution design.
However, from the viewpoint of maintaining the durability of the head 1, the thickness t is preferably at least 0.25 mm, more preferably at least 0.3 mm, still more preferably at least 0.35 mm, yet still more preferably at least 0.4 mm.
Preferably, the difference h between the heights of the unevenness of the convexo-concave wall portion 10, that is, the height from the most denting surface part 200a to the most protruding surface part 100a (shown in
If the height h is too large, there is a possibility that the convexo-concave wall portion 10 is decreased in the compressive and tensile rigidity in its own plane.
The sizes of the convexed portions 100 in the convexo-concave wall portion 10 are not particularly limited. But, in order to obtain a sufficient effect of increasing the bending rigidity without impairing the productivity and the workability, it is preferred that, in the top view of the convexo-concave wall portion 10, each convexed portion 100 has such a size that a smallest square s which circumscribes the convexed portion 100 (most protruding surface part 100a) as shown in
When the convexo-concave wall portion 10 is formed along a curved plane as in the present embodiment (
The convexo-concave wall portion 10 can be manufactured by various methods. For example, by pressing a thin metal sheet constituting the wall, the convexo-concave wall portion 10 can be formed on the metal sheet. By using such thin metal plate for a part of the wall or the entire wall, the head 1 in the present embodiment can be manufactured.
In the second example, each of the convexed portions 100 is composed of two rib-like first protrusions 101 extending straight in substantially parallel with the first direction D1, and two rib-like second protrusions 102 extending straight in substantially parallel with the second direction D2.
The first protrusions 101 extend parallel to each other, and are displaced from each other in the second direction D2.
The second protrusions 102 extend in parallel with each other, and are displaced from each other in the first direction D1. In this example too, the convexed portions 100 and the concaved portions 200 have the same contour shape.
Such convexo-concave wall portion 10 can also make the wall of the head 1 thinner without impairing the rigidity.
In this example too, the convexed portions 100 and the concaved portions 200 have the same contour shape.
Such convexo-concave wall portion 10 can also make the wall of the head 1 thinner without impairing the rigidity.
In the fourth example, each of the convexed portions 100 is composed of one rib-like first protrusion 101 and two rib-like second protrusions 102, and
the two second protrusions 102 are respectively connected to both ends of the first protrusion 101 in the form of a capital I. In the fourth example, each of the concaved portions 200 comprises one second concaved portions 202 and two first concaved portions 201, and the two first concaved portions 201 are respectively connected to both ends of the second concaved portions 202 in the form of a capital I.
In this example too, the convexed portions 100 and the concaved portions 200 have the same contour shape.
Such convexo-concave wall portion 10 can also make the wall of the head 1 thinner without impairing the rigidity.
While detailed description has been made of preferable embodiments of the present invention, the present invention can be embodied in various forms without being limited to the illustrated embodiments. Thus, it must be understood that the present invention includes all modifications, equivalents and alternatives falling within the spirit and scope of the invention as set forth in the appended claims.
Firstly, convexo-concave wall portions having specifications listed in Table 1 (test examples 1 to 3) were computer-simulated to obtain their bending rigidity.
The test examples 1 to 3 were each based on a 120×120 mm square flat plate made of a titanium base alloy and respectively provided with the convexo-concave patterns shown in
The results are shown in Table 1. As shown, the test example 1 having the pattern shown in
Further, the ratio of the maximum value of the bending rigidity and that of flat plate was obtained.
The results are also shown in Table 1. As shown, the test examples 1 to 3 had higher bending rigidity of about 7 to 15 times that of the flat plate although the material thickness was smaller than that of the flat plate.
Further, in order to evaluate the rigidity of the test example 1 when applied to the curved crown portion of a golf club head, a test example 4 was prepared by curving the test example 1 along a sphere in the computer-simulation so that the boundary between the convexed portions and the concaved portions (boundary N shown in
As shown in
In order to obtain the rigidity, the outer peripheral edge of the test example 4 was completely restrained or fixed to a flat plane, and a load from 0 to 100 N in the perpendicular direction to the flat plane was applied to the central point of the convexed surface the test example 4, and the deformation was calculated to obtain the displacement in the perpendicular direction of the central point.
Such deformation calculation was performed by changing the thickness to 0.30 mm, 0.35 mm and 0.40 mm, and changing the height difference h to 3.0 mm, 2.0 mm and 1.0 mm for each thickness.
Further, a comparative example which was the same as the test example 4 except that the thickness was 0.5 mm and no convexo-concave pattern was provided, was prepared and deformation calculation was performed similarly.
The obtained simulation results are shown in
Solid line: height difference h=3.0 mm
Long dashed line: height difference h=2.0 mm
Short dashed line: height difference h=1.0 mm
As is clear from
In general, displacement of a metal golf club head at the time of hitting a ball is at most 1.0 mm. In such a displacement range, the rigidity becomes highest when the height difference h is 2.0 mm at any thickness.
Further, it was found that, when the height difference h is in a range from 2.0 to 3.0 mm, the load and the displacement had a substantially linear relationship at any thickness.
Further, it was confirmed that, compared to the comparative example, the mass of the test examples 4 was reduced by about 1.7 g when the thickness t=0.30 mm and about 1.0 g when the thickness t=0.40 mm. Such reduced mass can be utilized to increase the moment of inertia of the golf club head.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-111079 | Jun 2019 | JP | national |
