JP2001170223A - Wood type golf club head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the directivity of a hit ball. SOLUTION: This wood type golf club head 1 is formed with a clubface F as a bulge B. The inertia moment I around a perpendicular axis passing the centroid point G of the head 1 in a reference state in which the head is placed on a horizontal plane by setting the head at a prescribed lie angle and loft angle is >=3500 (g.cm2). The following equation (1) is satisfied between this inertia moment I (g.cm2) and the radius R of curvature (cm) of the bulge: 0.01×I-13.0<=R<=0.01×I-2.0...(1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood type golf club head capable of improving the direction of a hit ball.

[0002]

2. Description of the Related Art As shown in FIG. 4, when a ball is hit with a wood type golf club head a, the center of gravity G of the head is set.
When the ball is hit on the toe side from the sweet spot point S, which is the foot of the perpendicular drawn to the face from the head a, the head a becomes the center of gravity G
Is rotated clockwise around the center, and the ball in contact with the head a is rotated counterclockwise (rotation of the hook when right-handed)
Takes a side spin. Conversely, when the ball is hit on the heel side of the sweet spot point S, the head a rotates counterclockwise around the center of gravity G, and the ball in contact with this head a is rotated clockwise (right-handed). If the slice rotation) takes a side spin.

[0003] Such a phenomenon is well known as a gear effect. When the face surface is flat, as shown in FIG. 4, the launched ball is launched in parallel with the target flight line direction j, but immediately with respect to the target flight line direction j by the side spin. Hook or slice large and skew left and right.

Conventionally, in order to solve such a problem,
As shown in FIG. 5, the wood-type golf club head a has a smooth curved surface having a finite radius of curvature R that protrudes outward when the face surface is viewed from a plane, that is, a bulge (horizontal face). Bulge) is being given. When the face surface is a bulge, as shown in FIG. 5, for example, when the ball is hit on the toe side from the sweet spot point S, the ball is once hit rightward at a deflection angle θ with respect to the target flight line direction j. Thereafter, an action of returning to the target flight line direction j is obtained by the side spin of the hook rotation. Conversely, when the ball is hit on the heel side of the sweet spot point S, the ball is launched slightly leftward with respect to the target flight line direction j, and then returns to the center by the side spin of the slice rotation. .

[0005]

By the way, in recent years, due to the development of wood type golf club head materials and manufacturing techniques, the size of the head has been remarkably increased. This increases the moment of inertia about the vertical axis passing through. Even when the head having a large moment of inertia hits the ball with the sweet spot point S removed from the toe side or the heel side, the rotational shake about the vertical axis passing through the center of gravity point G of the head is reduced, so that the gear effect described above causes The amount of given side spin is also reduced. Therefore, for example, as shown in FIG. 6, in the case of a head having a small bulge radius of curvature R (strong roundness) and a large moment of inertia, if the sweet spot point S is removed to the toe side or the heel side and the ball is hit, the ball swings Even though the angle θ is large, the amount of side spin corresponding to the angle θ is not obtained, so that the hit ball may not return to the target flight line direction j and the directionality may be degraded.

For example, in Japanese Patent Application Laid-Open No. Hei 8-196665, the moment of inertia of the head is set to 3000 (g · cm ² ) or more and the radius of curvature of the bulge is set to 40 cm or more.
In Japanese Patent Application Laid-Open No. 11-89976, the head volume is set to 220 to 320 (cm ³ ) and the radius of curvature of the bulge is set to four.
It has been proposed that each be 0 cm or more. However, in these proposals, a specific radius of curvature of a bulge suitable for the moment of inertia of the head is not given, and much room for improvement still remains.

That is, for the former, for example,
The moment of inertia is 4000 (gcm ^Two) If
The radius of curvature of Ruji can be anything as long as it is 40 cm or more.
For example, a large bulge with a radius of curvature of about 100 cm
The rate radius can also be determined. With such a head
Means that although the moment of inertia is large,
As a result of the flattening, the swing angle of the ball is small.
However, the side spin amount due to the gear effect tends to be excessive
The hit ball can deviate significantly from the target flight line.
Inferred easily.

As a result of various experiments, the inventors have found that in a wood type golf club head, the radius of curvature of the bulge on the face surface and the moment of inertia about a vertical axis passing through the center of gravity of the head are correlated. It is necessary to regulate, and even if the ball is hit without the sweet spot point, by appropriately controlling the balance between the swing angle given to the ball and the amount of side spin of the ball, They have found that the directionality of the hit ball can be stabilized, and have completed the present invention. As described above, an object of the present invention is to provide a wood-type golf club head that can improve the directionality of a hit ball.

[0009]

According to a first aspect of the present invention, there is provided a wood-type golf club having a bulge face, wherein the head is mounted on a horizontal plane at a predetermined lie angle and loft angle. In the reference state, the moment of inertia I about the vertical axis passing through the center of gravity of the head is 3500 (g · g).
cm ² ) or more and this moment of inertia I (g · cm
² ) A wood-type golf club head characterized by satisfying the following expression in terms of the bulge radius of curvature R (cm). 0.01 × I-13.0 ≦ R ≦ 0.01 × I-2.0 ...

When the radius of curvature of the bulge on the face surface is not uniform between the upper and lower sides of the face surface (between the crown portion and the sole portion), the radius of curvature R of the bulge becomes the radius of curvature of the bulge passing through the sweet spot point on the face surface. Specify by radius of curvature.

According to a second aspect of the present invention, there is provided the wood type golf club head according to the first aspect, wherein the following expression is satisfied. 0.01 × I-12.5 ≦ R ≦ 0.01 × I-2.6 ...

The invention according to claim 3 is the wood type golf club head according to claim 1 or 2, wherein the bulge has a radius of curvature R of 38.1 (cm) or less.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a wood-type golf club head (hereinafter, may be simply referred to as a “head”) 1 of the present embodiment, FIG. 2 is a front view of the same from the face side, and FIG. 3 is a view from the toe side. Each side view is shown. As shown in the figure, a head 1 of the present embodiment has a face portion 2 having a face surface F that forms a surface to hit a ball,
A crown portion 3 connected to the upper edge of the face portion 2 and forming the upper surface of the head, a sole portion 4 connected to the lower edge of the face portion 2 and forming the lower surface of the head, and a connection between the crown portion 3 and the sole portion 4 And a side portion 5, for example, a hollow portion is formed inside. In addition, the head 1 of this embodiment has a shaft mounting portion 6 to which a shaft (not shown) is mounted.
Exemplarily is provided integrally on the heel side of the crown portion 3.

As shown in FIG. 2A, the shaft center line C of the shaft mounting portion 6 is fixed to the vertical plane VP, and the head 1 has an angle formed by the shaft center line C and the horizontal plane HP. A certain lie angle α and a loft angle β which is an angle between the face surface F and the vertical line V as shown in FIG. The head 1 shown in FIG. 1 is shown as a reference state in which the head 1 is mounted on the horizontal plane HP at a predetermined lie angle α and a loft angle β (face angle is 0 °).

The head 1 has a face surface F at a bulge,
In other words, the head 1 is constituted by a curved surface which bulges outward and has a moment of inertia I about the vertical axis passing through the center of gravity G of the head 1 in the reference state is 3500 (g · cm ² ) or more. (G · cm ² )
With respect to the bulge radius of curvature R (cm), the following equation is satisfied. 0.01 × I-13.0 ≦ R ≦ 0.01 × I-2.0 ...

First, the head 1 according to the present invention is provided with the center of gravity G
Is about 3500 (g ·
cm ² ) or more. The moment of inertia I affects the rotational shake of the head 1 when the sweet spot point S of the face surface F is hit on the toe side or the heel side and the ball is hit.
By setting it to be not less than 00 (g · cm ² ), the rotational deviation itself is suppressed.

To increase the moment of inertia of the head 1, a) increase the weight of the head, b) increase the volume of the head, c) change the weight distribution by changing the thickness, shape, etc. of the head. Is mentioned. However, if the weight of the head is excessively heavy, the swing tends to be difficult, and if the head volume is excessively large, a sense of incongruity is likely to occur when the head is held,
This has the effect of increasing the height of the center of gravity of the head and increasing the backspin amount of the hit ball. Therefore, from these viewpoints, considering the characteristics of the current head material and manufacturing technology,
The moment of inertia I of the head is, for example, 3500 to 5
000 g · cm ² .

For example, titanium or a titanium alloy (for example, 6
Al-4V titanium) is used, the head volume eg 300 cm ³ or more, more preferably 380 cm ³ or more, more preferably by a 380～440Cm ^3, common swing is possible and can be set up without feeling In addition, it has been found from experiments by the inventors that the head 1 having an inertia moment I of 3500 g · cm ² or more can be manufactured. Further, the head 1 can be made of a high-strength fiber reinforced resin, a thermoplastic resin, a thermosetting resin, or the like, in addition to titanium and a titanium alloy, other materials, for example, other metal materials.

Further, the inventors made various prototypes of the existing head and the head 1 having a large moment of inertia as described above. FIG. 3 is a graph showing the relationship between the moment of inertia I of the head and the radius of curvature R of the bulge. The radius of curvature R of the bulge is measured at a position passing through the sweet spot point S, and the moment of inertia I of the head is expressed as IN
MOMENT OF INERTIA MEASURIN manufactured by ERTIA DYNAMICS Inc
It is the value measured using MODELNO.005-002 of G INSTRUMENT. As a result of various experiments, even when the sweet spot point S of the face surface F is hit to the toe side or the heel side and hit, the balance between the swing angle given to the ball and the amount of side spin of the ball is optimized. In order to achieve this, it has been found that the following equation must be satisfied in the moment of inertia I (g · cm ² ) of the head 1 and the radius of curvature R (cm) of the bulge. 0.01 × I-13.0 ≦ R ≦ 0.01 × I-2.0 ...

That is, if R <0.01 × I-13.0, the bulge becomes too strong in a head having an inertia moment I of 3500 (g · cm ² ) or more. For this reason, as illustrated in FIG. 6, for example, despite the large swing angle θ of the hit ball, it is difficult to obtain a side spin amount corresponding to the swing angle θ. A phenomenon that cannot return to j occurs. Conversely, if R> 0.01 × I−2.0, the bulge becomes too flat even for a head having an inertia moment I of 3500 (g · cm ² ) or more. For this reason, as shown in FIG. 4, for example, the swing angle of the hit ball is very small, and a phenomenon occurs in which the ball is excessively bent beyond the target flying line due to the side spin.

From such a viewpoint, the moment of inertia I (g · cm ² ) of the head 1 and the radius of curvature R of the bulge are obtained.
(Cm) can further stabilize the directionality of the hit ball by satisfying the following expression. 0.01 × I-12.5 ≦ R ≦ 0.01 × I-2.6 ...

As a result of various experiments by the inventors, in the case of a head having a moment of inertia I of 3500 g · cm ² or more, when the radius of curvature R of the bulge exceeds 38.1 cm, the ball is not hit when hit. The characteristics of the given side spin amount and deflection angle tend to sharply approach the characteristics of a head having a substantially flat face surface without a bulge, and the effect of improving the directionality of the ball is relatively small. Was found to decrease. That is, when the radius of curvature R of the bulge exceeds 38.1 cm, as shown in FIG. 4, when the ball is launched, the bulge is launched almost perpendicularly to the face surface F (in the direction of the target flying line), and then the side spin is applied. Tends to deviate from the target flight line direction. From such a viewpoint, the radius of curvature R of the bulge is set so as to satisfy the above-mentioned formula or the relationship in relation to the moment of inertia I of the head 1, and more preferably, the upper limit of the radius of curvature R of the bulge is 38.1 cm. Is particularly desirable.

[0023]

EXAMPLE A wood type golf club head was prototyped according to the specifications shown in Table 1, and a test hit test was performed with a club using this head. Each head is made of titanium alloy (6Al-4
V titanium), and the loft angle, lie angle, and face angle were all the same. Examples 1-3, Comparative Examples 1 and 2, a head volume 380 cm ^3, Example 4 and 5 and Comparative Examples 3 and 4 were the same 420 cm ^3.

Each head has the same shaft (Ferject FJ474 manufactured by Sumitomo Rubber Industries, Ltd.).
A wood-type golf club was prototyped with a carbon shaft) and the same grip (“Perfect Cord” manufactured by Serizawa Rubber Industries, Ltd.). This club has a total length of 11
4.3 cm, mass 280 g, and swing balance D0. The club is set on a swing robot and a golf ball (“MAXFLI HI-BRI” manufactured by Sumitomo Rubber Industries, Ltd.) is used at a head speed of 45 m / s.
D ”) and measures the swing angle (clockwise is positive), side spin amount (positive slice rotation), and deviation amount of the ball drop point from the target (positive on the right side of the target) of the launched ball. A test hit test was performed. In the test hit test, the position of the face hitting the ball was 20 mm on the toe side in the horizontal direction from the sweet spot point (toe side hit point), and 20 mm on the heel side in the horizontal direction from the sweet spot point (heel side). Hitting points), hit five balls at each position, and evaluated the average value of each. Table 1 shows head specifications and test results.
Shown in

[0025]

[Table 1]

In Example 1, the moment of inertia was 3505 g.
・ Because the radius of curvature R of the bulge is appropriate, although the cm ² is the smallest among the clubs, the displacement at the drop point was the smallest among all the clubs.

In the second embodiment, the moment of inertia is the same as that of the first embodiment, and the radius of curvature R of the bulge is larger than that of the first embodiment. Since the radius of curvature R of the bulge is larger than that in the first embodiment, the deflection angle is small, and therefore, the amount of deviation is small in the first embodiment.
It is slightly larger. However, since the relationship between the deflection angle and the amount of side spin is within an appropriate range, the amount of deviation at the drop point is small and good.

In the third embodiment, the moment of inertia is the same as that of the first embodiment, and the radius of curvature R of the bulge is smaller than that of the first embodiment. Since the radius of curvature R of the bulge is smaller than that of the first embodiment, the deflection angle is large, and therefore, the deviation amount is slightly larger than that of the first embodiment. However, since the relationship between the deflection angle and the amount of side spin is within an appropriate range, the amount of deviation at the drop point is small and good.

In the fourth embodiment, the radius of curvature R of the bulge is the same as that of the first embodiment, and the moment of inertia is larger than that of the first embodiment. Since the moment of inertia is large, the amount of side spin is small, the return of the ball due to the side spin is small, and the amount of deviation is slightly larger than in the first embodiment. However, since the relationship between the deflection angle and the amount of side spin is within an appropriate range, the amount of displacement at the falling point is small and good.

In the fifth embodiment, the moment of inertia and the radius of curvature R of the bulge are larger than in the first embodiment. Since the radius of curvature R of the bulge is larger than that in the first embodiment, the deflection angle is small, and since the moment of inertia is large, the side spin is small. The swing angle is small and the return of the hit ball due to the side spin is small, that is, the relationship between the swing angle and the amount of side spin is appropriate, and the shift amount at the drop point is small and good.

On the other hand, in Comparative Example 1, the radius of curvature R of the bulge is too small with respect to the moment of inertia I, so that the swing angle is large, and the hit on the toe side moves to the right, and the hit on the heel side turns to the left. , Each has a large displacement amount. In Comparative Example 2, since the radius of curvature R of the bulge is too large with respect to the moment of inertia I, the deflection angle is too small to shift leftward when hitting toward the toe and rightward when hitting against the heel. Has become. Further, although the moment of inertia I is large in Comparative Example 3, as in Comparative Example 1,
Since the radius of curvature R of the bulge is small, the deflection angle is large, and the shift amount is large in the right direction when hitting toward the toe, and in the left direction when hitting on the heel side. Further, in Comparative Example 4, the moment of inertia I is large, but as in Comparative Example 2, the radius of curvature R of the bulge is large, so that the swing angle is large, and the hitting toward the toe is leftward, and the hitting toward the heel is rightward. Each shift amount is large.

[0032]

As described above, according to the present invention,
By limiting the radius of curvature of the bulge of the face surface and the moment of inertia about the vertical axis passing through the center of gravity of the head in relation to each other, even if the ball is hit without the sweet spot point, it is given to the ball The swing angle and the amount of side spin of the ball can be appropriately controlled in a well-balanced manner, and a wood-type golf club head in which the directionality of the hit ball is stable can be realized.

[Brief description of the drawings]

FIG. 1 is a plan view of a head according to an embodiment of the present invention in a reference state.

FIG. 2 (A) is a front view of the same seen from the face side,
(B) is the side view seen from the toe side.

FIG. 3 is a graph showing a relationship between a moment of inertia I of a head and a radius of curvature R of a bulge.

FIG. 4 is a plan view illustrating a gear effect of a head having a flat face surface.

FIG. 5 is a plan view illustrating a gear effect of a head having a bulge face.

FIG. 6 is a plan view illustrating a gear effect of a head having a bulge face.

[Explanation of symbols]

 Reference Signs List 1 head 2 face portion 3 crown portion 4 sole portion 5 side portion B bulge F face surface G center of gravity of head I moment of inertia about a vertical axis passing through the center of gravity of head R radius of curvature of bulge

Claims (3)

[Claims] An inertia about a vertical axis passing through a center of gravity of a head in a reference state in which a head is mounted on a horizontal plane at a predetermined lie angle and a loft angle in a wood type golf club having a bulge face. When the moment I is 3500 (g
· Cm ²⁾ or more, and this moment of inertia I (g · cm ^2), the said bulge radius of curvature R (cm), wood-type golf club head that satisfies the following equation. 0.01 × I-13.0 ≦ R ≦ 0.01 × I-2.0 ... 2. The wood type golf club head according to claim 1, wherein the following formula is satisfied. 0.01 × I-12.5 ≦ R ≦ 0.01 × I-2.6 ... 3. The curvature radius R of the bulge is 38.1 (c
m) The wood type golf club head according to claim 1 or 2, wherein: