JP2003117030A - Golf club head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf club head having superior rebounding performance. SOLUTION: This golf club head 1 has a hollow part (i) inside. A face part 2 having a face surface F hitting a ball, includes a face central part 7, and a pleated part 9 having the annular shape surrounding a central part 7 of the face, and projecting to the hollow part (i) in a state of being folded in the approximately U-shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf club head capable of improving resilience performance.

[0002]

2. Description of the Related Art Golf clubs that fly well can play an important role in improving the score in golf competitions. There are various cases in which a golf club that flies well can be considered, and the following (1) to (3) are generally mentioned. It flies well because the hit ball is hard to bend, so the head speed and swing speed increase, so it flies well Even if you hit the sweet spot without hitting the sweet spot (that is, even if the flight distance when hit with the sweet spot is the same, you hit the sweet spot without hitting it) If the decrease in the flight distance when hitting is small, the average flight distance after repeated hits will increase and it will feel like a club that flies well) Fly well when hit with a sweet spot

With regard to the above items (1) and (2), in order to suppress the bending of the hit ball and to reduce the loss of flight distance at the time of a miss hit, various improvements have been made to the head shape and weight distribution such as enlarging the club head and increasing the moment of inertia. Has been done. Regarding the above, by devising the weight and balance of the club, the length of the shaft, the rigidity distribution, etc.,
Attempts have been made to increase the head speed immediately before hitting a golf ball, but it is difficult to obtain a remarkable effect because it is easily affected by the swing motion and arm strength of each golfer. Further, the above is a problem that club makers are particularly paying attention to, since it remarkably appears in the flight distance at the time of a nice shot.

In order to solve the above problems, it is effective to increase the coefficient of restitution of the head. The coefficient of restitution of the head minimizes energy loss at the time of hitting the ball and hits the ball in a high repulsion state. It can be increased by that. In particular,
It is considered effective to reduce the thickness of the face portion of the head as much as possible and bring the first-order minimum value of the frequency transfer function of the golf club or golf club head closer to that of the ball (for example, Japanese Patent Publication No. 5-33071). See the bulletin).

Therefore, in recent years, in order to further reduce the wall thickness while maintaining the strength of the face portion, it has been proposed to use a β-type titanium alloy or amorphous alloy, which is a material having a low Young's modulus and high strength, for the face portion. Has been done. However, in order to achieve higher resilience by selecting materials, there is no choice but to wait for the completion of new materials, and there is a limit at present.

On the other hand, efforts have been made to obtain a high coefficient of restitution while utilizing the existing metal materials by structurally devising it. For example, in order to reduce the rigidity of the face portion, it is effective to increase the face surface. The head having a large face area has a slightly lower strength than the head having the same face thickness but a small face area, but the rigidity can be further reduced. Therefore, if the thickness of the face portion is set so that the strength can be maintained, the rigidity can be reduced while maintaining the strength. However, the increase in the area of the face surface leads to an increase in the volume of the entire head, which leads to an increase in the weight of the head. On the other hand, since the club swings by a person, the weight of the club head cannot be extremely increased empirically, and as a result, there is a limit to the high resilience by enlarging the face surface.

The present invention has been devised in view of the above problems, and a face portion having a face surface for hitting a ball has an annular shape surrounding the center portion of the face and a cross section in a hollow portion inside the head. To provide a golf club head capable of effectively lowering the rigidity of the face portion and improving the resilience performance without increasing the weight of the head on the basis of providing a pleated portion which is bent and protrudes in a substantially U shape. It is an object.

[0008]

According to a first aspect of the present invention, there is provided a golf club head having a hollow portion therein, wherein the face portion having a face surface for hitting a ball has a face central portion and a face central portion. It is characterized in that it has an annular shape surrounding the center part of the face, and includes a fold-shaped part which is bent and protrudes in a substantially U-shaped cross section in the hollow part.

Further, the pleated portion can form a groove-shaped portion extending the face surface by a concave portion formed by bending the U-shaped cross section. The face surface can be made substantially flush with the groove portion by disposing an elastic material that can be deformed following the face portion when hitting a ball, for example. It is desirable that such a groove portion has a width GW on the face surface of 1 to 10 mm and a recess amount GD of 2 to 10 mm. Further, the plate thickness Tp of the pleated portion is
It is desirable that the thickness is smaller than the plate thickness Tc at the center of the face.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a golf club head (hereinafter, may be simply referred to as “head”) 1 of the present embodiment.
Is a front view of a normal state in which is placed on a horizontal plane with a prescribed lie angle and face angle, FIG. 2 is an exploded perspective view thereof, and FIG. 3 is an enlarged sectional view taken along line AA of FIG.

In the figure, a head 1 uses a face portion 2 having a face surface F for hitting a ball, and an upper edge Ea of the face surface F (the reference numeral "E" is simply used when referring to the entire peripheral edge of the face surface). ), Which forms the upper surface of the head, and the sole portion 4 which forms the bottom surface of the head, which connects to the lower edge Eb of the face F, and the crown portion 3.
Between the toe and the sole portion 4, and a side portion 5 extending from the toe side edge Ec of the face surface F to the heel side edge Ed of the face surface F, the face portion 2, the crown portion 3, and the side portion 5. And a neck portion 6 which is arranged in the vicinity of the intersecting portion on the heel side with and on which one end of a shaft (not shown) is mounted. The head 1 of this example is a wood type such as a driver (# 1) having a hollow portion i therein. The hollow portion i may be left in a hollow state, but may be filled with, for example, a foamed resin or the like that does not substantially contribute to the rigidity of the head.

The head 1 can be made of various metal materials such as aluminum alloy, titanium, titanium alloy, and stainless steel. In this example, Ti-6Al-4V, which is an α + β type titanium alloy, is adopted, and is manufactured by molding one or more parts by, for example, the lost wax precision casting method and, if necessary, joining them together. Is illustrated. However, it is needless to say that the material is not limited to this, and can be manufactured by another material or another molding method.

The head 1 of the present invention comprises the face portion 2
In addition, a face center portion 7 and a pleated portion 9 which is annular and surrounds the face center portion 7 and which is bent and protrudes into the hollow portion i in a substantially U-shaped cross section.

The face center portion 7 is a portion suitable for hitting a ball and is defined as a region having a certain area including at least the sweet spot SS.
As shown in FIG. 3, the sweet spot SS is a point where a normal line drawn from the center of gravity G of the head perpendicularly to the face surface F intersects with the face surface F. Also, this face center 7
Is formed such that its face side surface is substantially flat. The term "substantially flat surface" means a fine groove or recess for improving friction with a ball recognized under the golf rules, such as score line grooves and punch marks (both not shown). There is no problem in providing it.

The area of the center portion 7 of the face (the area surrounded by the groove portion 10 described later) is not particularly limited, but in consideration of variations in actual hitting points of average golfers and the like, it is preferable that the face portion be the face. It is desirable to secure about 30 to 80%, more preferably about 40 to 70% of the area of the surface F (the area surrounded by the peripheral edge E of the face surface, which is measured in a state where the groove-shaped portion 10 described later is filled). . It should be noted that the "rim of the face surface" is specified by the ridge line when it is clear, but when it is unclear, the "periphery of the face surface" is shown in FIG.
As shown in (A), a tangent to the face surface F passing through the sweet spot point SS (A to D in FIG. 10A)
(Only four of them are shown) FR is drawn,
As shown in (C), an inclined line U extending toward the rear of the head is drawn at an angle of 45 ° with respect to each tangent line R, and the intersections of the inclined line U and the head surface are continuously obtained and specified. sell.

As shown in FIG. 1, the pleated portion 9 has a continuous annular shape so as to surround the face central portion 7, but as shown in FIG.
Various forms can be adopted, such as those having e and 9o, and further, as shown in FIG. 5, plural ones are intermittently arranged to form a discontinuous annular shape. The pleated portion 9 defines the shape of the face center portion 7. Therefore, in consideration of the distribution of variations of actual hitting points of an average golfer and the like, the shape of the face center portion 7 should be a horizontally long shape or a horizontally long elliptical shape along the peripheral edge E of the face centering on the sweet spot SS. It is desirable to form the pleats 9 in an annular shape. However, it may be formed in a circular shape.

Further, the pleated portion 9 has a substantially U-shaped cross section in this example.
A groove portion 10 extending the face surface F is formed by a concave portion formed by bending in a letter shape. That is, as shown in FIG. 6, the groove-shaped portion 10 includes a pair of groove wall portions 10 a and 10 a which are spaced apart from each other and face each other, and the groove wall portion 10.
a and a groove bottom portion 10b connecting between 10a and 10a. Groove wall 1
In the present example, 0a and 10a are illustrated as being substantially perpendicular to the face surface F and parallel to each other.
Further, the groove bottom portion 10b is formed by an arc-shaped curve in this example, and prevents stress concentration and the like at the groove bottom portion 10b. Further, on the hollow portion i side, it is desirable that chamfering is appropriately performed at the intersection j between the pleated portion 9 and the inner surface of the face central portion 7 by an arc to prevent stress concentration. In addition, as shown in FIG. 7, the "substantially U-shaped cross section" is a cross section in which the groove walls 10a and 10a of the groove-shaped portion 10 facing each other are not parallel to each other and the width gradually increases toward the face surface F side. Includes shape.

Since such a pleated portion 9 is bent and protrudes toward the hollow portion i in a substantially U-shaped cross section, for example, the crown portion 3 and the sole portion 4 are not changed in shape or weight is increased. Within a limited head weight range, the area of the face surface F can be artificially expanded and the face portion 2 can be made low in rigidity. When the ball is hit with the face central portion 7 and the face central portion 7 is displaced toward the hollow portion i,
Rather than the face portion 2 being locally displaced, the face portion 2
It is advantageous in terms of durability to secure the displacement as a whole. In the head 1 of the present invention, since the pleated portion 9 can elastically support the face center portion 7 that hits the ball, it is possible to reduce the concentration of displacement in the face center portion 7 that directly contacts the ball at the time of hitting the ball. Since the face portion 2 is flexed in a well-balanced manner, it is also advantageous in durability. In this way, by providing the pleated portion 9 on the face portion 2, the face portion 2
It is possible to reduce the rigidity of the face portion 2 while maintaining the strength of No. 1 and achieve high resilience performance.

As shown in FIG. 5, the groove portion 10 has a width GW on the face F that is set to, for example, 1 to 10 mm, more preferably 2 to 8 mm, and further preferably 2 to 5 mm. . If the width W is larger than 10 mm, considering the actual variation of the hitting points of average golfers and the like, the area of the face central portion 7 at which the ball should be hit tends to be too small, which is not preferable. When it becomes smaller than 1 mm, such groove 1
The pleats 9 having 0 are difficult to form. Further, the recess amount GD of the groove portion 10 is preferably 2 to 10 mm, more preferably 2 to 9 mm, and further preferably 4 to 8 mm. When the recessed amount GD is less than 2 mm, the face portion 2
The effect of lowering the rigidity is reduced, and conversely, if it exceeds 10 mm, molding becomes difficult, and the weight increase of the pleated portion 9 tends to be larger than that of the structure without the pleated portion 9. Further, the groove width GW and / or the recess amount GD can be changed in addition to the case of being formed constant.

Further, as shown in FIG. 6, the plate thickness Tp of the pleated portion 9 may be the same as the plate thickness Tc of the face center portion 7, but it is particularly preferably smaller than the plate thickness Tc. desirable. In this way, by making the plate thickness Tp of the pleated portion 9 smaller than the plate thickness Tc of the face center portion 7, the spring constant of the pleated portion 9 is lowered, the face portion 2 is made less rigid, and the resilience performance is improved. Can be improved. The plate thickness Tc of the face center portion 7 is preferably 2.0 to 4.0 mm, more preferably 2.2 to 3.5 mm, further preferably 2.5 to 3.
It is desirable to set it to 5 mm. If the plate thickness Tc is less than 2.0 mm, the durability of the face portion tends to decrease, and conversely, if it exceeds 4.0 mm, low rigidity is impaired and the resilience performance tends to deteriorate. On the other hand, the plate thickness Tp of the corrugated portion 9
Is preferably 0.3-of the plate thickness Tc of the face center portion 7.
It is desirable to set 0.9 times, more preferably 0.4 to 0.7 times.

When the pleated portion 9 is formed, its forming position is not particularly limited. However, when the pleated portion 9 is too close to the peripheral edge E of the face surface F, the pleated portion 9 is formed in the hollow portion i, for example, the crown portion 3 or the sole portion. It is not preferable that it interferes with the inner surface of 4 or the like, or the molding thereof becomes difficult. Further, even if the pleats 9 are too close to the sweet spot SS side, the area occupied by the face central portion 7 may be compressed and the sweet area may be reduced. From this point of view, the separation width S between the peripheral edge E of the face surface and the groove edge outside the groove-shaped portion 10 is determined.
(Shown in FIG. 8) is, for example, preferably 2 to 15 mm, more preferably 3 to 8 mm. As a result, the face surface F has a flat peripheral portion 13 formed between the peripheral edge E and the groove portion 10.

Further, as shown in FIG.
It is also possible to dispose the elastic material 11 which can be deformed following the face portion 2 when hitting a ball. As a result, the face surface F
Can be substantially flush. The elastic material 11 is not particularly limited as long as it can exhibit the above-mentioned action, but various rubbers and resins, particularly ionomer resins used for golf balls and the like are preferable in that they can withstand deformation. .

In this way, by disposing the elastic material 11 in the groove-like portion 10 so that the face surface F is flush, the fold-like portion 9 is formed.
It is possible to prevent mis-hits due to the unevenness of the groove-like portions 10 when hitting a ball without impairing the low rigidity of the face portion due to, and to prevent a sense of discomfort at the time of holding. Further, it is preferable in that it is possible to prevent foreign matter such as earth and sand or lawn from being caught in the groove portion 10. Further, after the elastic material 11 is filled inside the groove state 10, for example, by evenly coating it, the visibility of the pleated portion 9 can be obstructed from the outside, and a feeling of strangeness in the appearance of the head or the like is also caused. It can be prevented.

FIG. 9 shows another embodiment of the present invention.
In this form, the plate thickness Tc of the face center portion 7 changes. That is, for example, the plate thickness Tc of the sweet spot SS and its peripheral region where the stress is high at the time of hitting the ball.
It is possible to adopt a design concept utilizing the concept of "equal strength" according to the generated stress, with 1 being the maximum and the plate thickness Tc2 in the peripheral region where the stress is relatively small being relatively small. In this embodiment, the amount of bending of the entire face center portion 7 can be increased while maintaining the strength, and the rigidity of the face portion 2 can be reduced more effectively and the resilience performance can be improved, as compared with the above-described embodiment. If the plate thickness Tc2 is too small, the generated stress is small,
Since fatigue fracture due to repeated use can be considered, the ratio (Tc2 / Tc1) of the plate thicknesses is preferably set to, for example, 0.3 to 0.9, more preferably 0.5 to 0.8. Is desirable.

Further, in the normal state shown in FIG.
It is also preferable to design the aspect ratio, which is the ratio (h / w) of the height h of the face surface F and the width w of the face surface F, to approach 1.0. Specifically, the aspect ratio is 0.6 to
Set to about 1.0. This is, for example, in Japanese Patent Laid-Open No. 2001-2001.
As described in 95955, by the shape effect of the face portion 2, it is possible to increase the amount of bending of the face portion at the time of hitting a ball and improve the resilience performance.

Although the embodiment of the present invention has been described above by taking the wood type golf club head as an example, the present invention is not limited to such a form, and any head having a hollow portion can be used. It is also applicable to iron type, utility type, and putter type.

[0027]

EXAMPLES Examples in which the present invention is embodied will be described below. A plurality of wood-type golf club heads having a head mass of 190 g made of titanium alloy (Ti-6Al-4V) were prototyped based on the specifications of Table 1, and the restitution coefficient and durability of each head were tested. In addition, heads of substantially the same shape having a configuration other than the present invention were also prototyped and their performances were compared. In the head of the example, the area of the central portion of the face was set to 50% of the total area of the face surface. In addition, the width GW of the groove-shaped portion is 2 mm, and the amount of depression GW is 4 mm.
Unified. The test method is as follows.

<Repulsion coefficient (Spring effect test US
GA method)> The repulsion characteristic of the head is S. G. A. of
Procedure for Measuring the Velocity Ratio of a
Club Head for Conformance to Rule 4-1e, Revision 2
(February 8, 1999). Specifically, a golf ball is shot by using a ball launching device and is made to collide with a sweet spot on a face portion of a head mounted without being fixed on a pedestal, and an incident velocity Vi and a rebound velocity immediately before the collision of the golf ball. Measure Vo and. Then, when the incident velocity of the golf ball is Vi, the rebound velocity is Vo, the head mass is M, and the average mass of the golf ball is m, the restitution coefficient e was calculated by the following formula. (Vo / Vi) = (eM-m) / (M + m) The distance from the launch port of the golf ball to the face part is 55 inches, and the ball is not more than 5 mm away from the head sweet spot position and the face surface is Make a right-angled collision with. The golf ball uses Pinnacle Gold made by Titleist, and the initial ball speed is 160
Feet ± 0.5 feet (48.768 ± 0.152
4 m / s).

<Durability> The same shaft made of FRP was attached to each test head to make a 46-inch wood type golf club as a prototype, and the club was attached to a swing robot so that the head speed was 50 m / s. The golf ball was hit with a sweet spot of 3,000 balls for each club, and the degree of damage to the face surface was visually observed. The test results are shown in Table 1.

[0030]

[Table 1]

As a result of the test, it can be confirmed that the example has an increased restitution coefficient as compared with the comparative example. In addition, it was confirmed that it has sufficiently practical performance in terms of durability. Next, examples were made in which the width of the groove-shaped portion and the amount of recess were different, and the performance was compared. The measurement results are shown in Table 2.

[0032]

[Table 2]

[0033]

According to the inventions of claims 1 and 2,
The face portion includes a center portion of the face and a pleated portion which is formed in an annular shape and surrounds the center portion of the face and which is bent and protrudes in a hollow portion into a substantially U-shaped cross section, thereby increasing the restitution coefficient and the flight distance of a hit ball. Can be improved.

According to a third aspect of the present invention, the groove portion formed on the face surface side by the pleated portion is filled with an elastic body which can be deformed to follow the face portion when hitting a ball, and the face surface side. When it is made substantially flat, it is possible to prevent foreign matter from being caught in the groove-like portion without impairing the bending characteristic of the face portion, and also to prevent a feeling of strangeness in appearance.

Further, as in the invention described in claims 4 to 5, by limiting the width GW and the amount of depression GD of the groove portion, or the plate thickness Tp of the pleated portion is set to be smaller than the plate thickness Tc of the face central portion. By making it smaller, the rigidity of the face portion 2 can be reduced more effectively and surely.

[Brief description of drawings]

FIG. 1 is a front view of a head showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view thereof.

FIG. 3 is a sectional view taken along the line AA.

FIG. 4 is a front view of a head showing another embodiment of the present invention.

FIG. 5 is a front view of a head showing another embodiment of the present invention.

FIG. 6 is an enlarged sectional view of a pleated portion.

FIG. 7 is an enlarged cross-sectional view of a pleated portion.

FIG. 8 is an enlarged cross-sectional view showing another form of the pleated portion.

FIG. 9 is a sectional view of a head showing another embodiment of the present invention.

10A to 10C are schematic diagrams for explaining the peripheral edge of the face surface.

[Explanation of symbols]

1 golf club head 2 face part 3 Crown 4 sole part 5 side parts 7 Face center 9 folds 10 Groove 11 Elastic material C sweet spot F face surface GW Groove width GD Groove amount of groove

Claims (5)

[Claims] 1. A golf club head having a hollow portion inside, wherein the face portion having a face surface for hitting a ball has a center portion of the face and an annular shape surrounding the center portion of the face, and the hollow portion has a cross section. A golf club head comprising: a fold-shaped portion that is bent and protrudes in a substantially U shape. 2. The golf club head according to claim 1, wherein the pleated portion forms a groove portion extending through the face surface by a concave portion formed by bending the U-shaped cross section. 3. The groove-shaped portion is provided with an elastic material which can be deformed following the face portion when hitting a ball, and the face surface is flush with the elastic material. Golf club head. 4. The width GW of the face surface of the groove portion is 1
The golf club head according to claim 2 or 3, wherein the golf club head has a depth of -10 mm and a recess amount GD of 2 to 10 mm. 5. The golf club head according to claim 1, wherein a plate thickness Tp of the pleated portion is smaller than a plate thickness Tc of the face center portion.