JP2001000590A - Golf club head, golf club and golf club set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf club head, golf club and golf club set which may be improved in the directivity of a hit ball and decreased in the variations of a carry. SOLUTION: The inclination of a major axis 9b of a cut elliptic face 7 obtained when the ellipsoid of inertia 6 of the golf club head 1 is cut from the plane which passes the centroid G of the golf club head and is parallel to the face reference face passing the centroid G with respect to a reference axis α parallel with the intersecting line of the face reference face of the golf club head 1 and a ground surface is >=0 to <=45 deg. in a direction uphill on toe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a golf club head, a golf club, and a golf club set.
More specifically, the present invention relates to a golf club head, a golf club, and a golf club set that can improve the directionality at the time of hitting a ball and reduce variation in flight distance.

[0002]

2. Description of the Related Art Conventionally, performance required of a golf club includes realizing a sufficient flight distance of a hit ball and stabilizing the directionality of the hit ball. In particular, the direction of the hit ball affects whether or not the golfer can keep the fairway, and is one of the major factors influencing the score. Here, the directionality of the hit ball greatly varies depending on the position of the hit point at which the golf club head hits the golf ball (also referred to as a ball). Except for professional golfers and top amateurs, many ordinary golfers hit golf balls at various positions on the face of a golf club head. Therefore, when the ball is hit at the intersection of a vertical line drawn from the center of gravity of the golf head to the face and the face (hereinafter referred to as a sweet spot), the direction of the hit ball is stable, When the ball is hit in an area other than the spot, the direction in which the hit ball flies varies. That is, the directionality of the hit ball deteriorates.

[0003] Therefore, conventionally, even when the ball is hit at a position away from the center of gravity of the golf head, the moment of inertia of the golf head is controlled so that the directionality of the hit ball does not vary.
Especially when the golf club head is set on the ground,
Various methods have been proposed to increase the moment of inertia in the heel direction.

For example, a first conventional example is disclosed in
No. 6,799,91, the center of the toe and hosel weight members is above the horizontal axis that is horizontal to the ground through the center of gravity of the golf club head when the golf club is lying at the address. A golf club head is disclosed. In this way, the moment of inertia around the horizontal axis and the vertical axis passing through the center of gravity can be increased.

A second conventional example is disclosed in Japanese Patent Application Laid-Open No. 9-14 / 1991.
Japanese Patent No. 9954 discloses the following golf club head. That is, when the golf club head is arranged on a plane, the Z-axis extending in the direction parallel to the tangential direction of the face surface and extending in the horizontal direction and the direction perpendicular to the plane.
Of the three principal axes of inertia having the origin at the center of gravity of the golf club head on the XZ plane defined by the axis and the straight line obtained by projecting the inertial principal axis having the smallest angle with the X axis onto the XZ plane and the X axis. The angle is defined to be in a range of 10 ° or more and 40 ° or less.

Further, as a third conventional example, Japanese Patent Laid-Open Publication No. 1-3
No. 00970 discloses a wood club head in which the weight of the hosel portion is set to 5% or less of the weight of the head body and the length is set to 4 cm or less, so that the principal axis of inertia is horizontal.

As a method for improving the directionality of a hit ball, various proposals have been made for a technique for increasing the moment of inertia of a golf club head. For example, as a fourth conventional example, a so-called cavity structure in which a hollow portion is provided inside an iron head main body and a peripheral portion is thickened is known. As a fifth conventional example, there is known a technology in which an iron head has a hollow structure in which the inside is completely hollow.

[0008]

Here, the magnitude and direction of the force at the time of collision between the golf club head and the golf ball will be considered. When hitting a golf ball with a golf club,
As shown in FIG. 1, the golf club head 1 receives a striking force F from the ball 2 in the striking direction. Since the golf club head 1 has a loft angle δ according to its count, the striking force F at the time of striking can be decomposed into a component force FH parallel to the face surface and a component force FP perpendicular to the face as shown in FIG. . The component force FH is a force for rotating the ball 2 together with the frictional force on the face surface (a force for generating a back spin or a side spin).
On the other hand, the component force FP is a force for rotating the golf club head 1. For this reason, the position at which the ball 2 is hit
Away from the golf club head 1
Is rotated, and the flying direction of the hit ball 2 deteriorates.

The above-mentioned conventional example will be examined from such a viewpoint. First, Japanese Unexamined Patent Application Publication No. 7-67991 as the first conventional example discloses a method of increasing the moment of inertia of a golf club head. However, no particular consideration is given to the moment of inertia in a direction perpendicular to the face surface of the golf club head. That is, as described above, no measures are taken for the rotation of the golf club head due to the component force FP (see FIG. 1) when the ball is hit at a position away from the center of gravity of the golf club head. Therefore, the directionality of the hit ball may be deteriorated.

A second conventional example is disclosed in Japanese Patent Laid-Open No. 7-1.
In Japanese Patent No. 49954, only the direction of the principal axis of inertia of the golf club head is set within a certain angle range with respect to the horizontal axis, and the rotation of the golf club head when hitting a golf ball is suppressed. Therefore, it is not specifically considered to increase the moment of inertia perpendicular to the face surface.

In the above-mentioned Japanese Patent Application Laid-Open No. Hei 9-149954, the horizontal direction is assumed as the direction of the distribution of hit positions of the golf club head (hitting point distribution). The spots at have variations also in the vertical direction. Also, the distribution of the variation of the hit points changes depending on the golf club count. For this reason, Japanese Unexamined Patent Application Publication No. 9-14995, which considers only the horizontal direction as the direction of the variation of the hit points,
In Japanese Patent Application Publication No. 4 (1994), variations in the flight distance of a hit golf ball occur due to variations in the vertical direction of the hit points.

Here, a perpendicular is drawn on the face through the center of gravity G (see FIG. 1) of the golf club head, and a point where the perpendicular and the face intersect is referred to as a sweet spot (SS). If the distance between the sweet spot SS and the hit point at which the golf ball is hit is increased, the golf club head is more likely to rotate at the time of hitting. on the other hand,
In the above-mentioned Japanese Patent Application Laid-Open No. 9-149954, a principal axis of inertia about the center of gravity G of the golf club head is considered. Therefore, when the golf club count becomes large and the loft angle δ becomes large, the sweet spot is located at a position considerably higher than the position of the center of gravity G. Therefore, the center of gravity G in the golf club head is
If you set a hit point on the face surface at a height almost the same as the hit point, this hit point will be separated from the sweet spot, and the directional variation of the hit ball may be rather large there were.

A third conventional example is disclosed in Japanese Patent Laid-Open Publication No. 1-3
In the golf club head having the above-described configuration, the golf club head having the above-described configuration makes the main axis of inertia substantially horizontal so that the hit point hitting the ball deviates from the sweet spot in the horizontal direction. A golf club head that does not deteriorate in directionality is disclosed. However, in the golf club head disclosed in Japanese Patent Application Laid-Open No. 1-300970, there is a disadvantage that the variation in the flight distance of the hit ball does not improve much with respect to the variation in the hitting point in the vertical direction.

Further, in the fourth conventional golf club head cavity structure, although the effect of increasing the moment of inertia of the golf club head is provided, only the peripheral portion of the golf club head is made thicker, and the face is not thickened. The effect of increasing the moment of inertia in the direction perpendicular to the plane was small.

The effect of increasing the moment of inertia of the golf club head is also recognized in the hollow structure cited as the fifth conventional example, but in this case, the moment of inertia in the direction perpendicular to the face is also increased. The effect was small.

As described above, hitherto, golf club heads have been proposed in which the directionality of a hit golf ball is improved or the moment of inertia itself of the golf club head is increased. It has been difficult to realize a golf club head that can improve the directionality of the golf club and at the same time reduce the variation in the flight distance.

The present invention has been made to solve the above problems, and one object of the present invention is to
An object of the present invention is to provide a golf club head capable of improving the directionality of a hit golf ball and, at the same time, reducing variations in the flight distance of the ball.

Another object of the present invention is to provide a golf club capable of improving the directionality of a hit golf ball and, at the same time, reducing variations in the flight distance of the ball.

Another object of the present invention is to provide a golf club set capable of improving the directionality of a hit golf ball and, at the same time, reducing variations in the flight distance of the ball.

[0020]

SUMMARY OF THE INVENTION In one aspect of the present invention, a golf club head is provided with respect to a reference axis that passes through the center of gravity of the golf club head and is parallel to the intersection of the face reference plane of the golf club head with the ground. The inclination angle of the major axis of the cut elliptical surface obtained when the inertial ellipsoid of the golf club head is cut by a plane passing through the center of gravity and parallel to the face reference plane is 0 ° or more and 45 ° or less in the toe-up direction ( Claim 1).

Here, the face reference surface corresponds to the face surface when the hitting surface (face surface) for hitting a ball such as an iron club head is flat. Also, when the face surface is a convex curved surface, such as a golf club head of a general wood club, the center of gravity of the face surface, the sweet spot, or the surface including the outer periphery of the face surface is most often used. A plane at a point on the face surface at a distance that is in contact with the face surface. Since the center of gravity or the sweet spot of the face surface described above is concentrated at substantially the same position, no significant difference occurs even if the tangent of the hitting surface at any point is used as the face reference surface.

Conventionally, in a golf club head, in order to improve the directionality of a hit ball, a projection area or a projection area of an inertia ellipsoid of the golf club head is projected on a face surface of the golf club head. The direction of the principal axis of inertia was thought to have an effect.
However, as a result of the research, the inventors have found that the size of the cut ellipsoid of the inertial ellipsoid of the golf club head and the direction of the long axis of the cut ellipsoid as described above indicate the directionality of the hit ball and the flight distance in the golf club head. Was found to affect the variability. That is, by aligning the direction of the major axis of the cut ellipsoid with the direction of the distribution of the hit points in the golf club head, the directionality of the hit ball is improved even when the hit points vary, and the flying distance is reduced. It has been found that variations can be reduced. And, as will be described later, the direction in which the hit points vary is a direction inclined in the toe-up direction in the golf club head. For this reason, if the inclination angle of the major axis of the cut elliptical surface with respect to the reference axis is set to 0 ° or more and 45 ° or less in the toe-up direction, when the hit points vary, the directionality of the hit ball is improved, and It has become possible to reduce the variation in the flight distance of the ball.

In the golf club head according to the one aspect, the tilt angle may be 0 ° or more and 30 ° or less (claim 2).

In the golf club head according to the one aspect, the inclination angle may be 0 ° or more and 15 ° or less.

Here, when a beginner hits a golf ball, the direction of variation of the hit points may become closer to the horizontal direction due to wobbling of the upper body. In such a case, by setting the inclination angle of the major axis of the cut ellipse as described above, it is possible to more reliably improve the directionality of the hit ball and reduce the variation in the flight distance of the ball. Becomes possible.

In the golf club head according to the above aspect, an axis passing through the center of gravity of the golf club head and perpendicular to the ground is defined as a Z-axis, an axis parallel to the intersection line and passing through the center of gravity is defined as an X-axis. An angle between the projection main axis and the X axis, which is obtained by projecting one of the main axes onto a plane defined by the Z axis and the X axis, is 0.
It may be not less than 9 ° and not more than 9 ° (claim 4).

In this case, the angle formed between the principal axis of projection of the inertial ellipsoid and the X axis is set in the above range, whereby
The horizontal deflection of the golf club head when hitting the golf ball can be reduced. As a result, the directionality of the hit golf ball can be further improved.

A golf club according to another aspect of the present invention includes the golf club head according to the above aspect, and a shaft having one end connected to the golf club head.

A golf club set according to another aspect of the present invention is a golf club set including the golf club according to the above other aspect, wherein the golf club has a first golf club and a count higher than that of the first golf club. A large second golf club. The tilt angle of the first golf club is selected from a first angle range. The tilt angle of the second golf club is a second angle larger than the first angle range.
(Claim 6).

In the golf club set according to the another aspect, the tilt angle of the second golf club may be greater than or equal to the tilt angle of the first golf club.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.

FIGS. 1 and 2 are schematic side views of a golf club head for explaining the principle of the present invention. FIG.
Describes the impact force generated on the face surface when a golf ball is hit with a golf club head. FIG. 2 shows a state where the face rotates and the ball jumps out when hit.

Referring to FIG. 1, when a golf club head (also called a club head) 1 hits a ball 2, the club head 1 hits the ball 2 at the hitting position of the ball 2 in the traveling direction of the golf club swing. Receive force F. The club head 1 has an angle between the sole and the face surface in order to obtain a flight distance for each count by changing the angle of the ball 2 to fly out according to the count. This angle is called the loft angle δ. The loft angle δ is usually set to about 10 ° for a driver, about 20 ° for a 3 iron, about 30 ° for a 6 iron, and about 40 ° for a 9 iron. That is, the loft angle δ is set to increase as the number increases.

The striking force F at the time of striking, as shown in FIG.
A component force FH parallel to the face and a component force FP perpendicular to the face
And can be disassembled. This component force FH is a force for rotating the ball 2 together with the frictional force on the face surface. For this reason, back spin and side spin are generated by this component force FH. When the swing speed is high and the collision speed of the club head 1 with the ball is high, the hitting force F becomes large. When the impact force F increases, the component force FH also increases, and back spin and side spin are likely to occur. For example, the ball of an iron such as a professional golfer soars upward after a shot and then appears to fall almost perpendicular to the ground. This is because the ball floats upward and then falls.

Next, referring to FIG. 2, a component force FP perpendicular to the face surface is a force for rotating the club head 1. The rotation of the club head 1 causes the ball 2 after the shot to fly up and down or left and right.

Here, it is known that if the ball 2 is hit at the sweet spot SS, the ball 2 will fly the best. When the ball 2 is hit at the sweet spot SS, the club head 1 hardly rotates. That is, the directionality of the hit ball is stabilized. However, when a general player except a professional golfer or a top amateur performs a shot, it is difficult to stably hit the ball 2 at the sweet spot SS of the club head 1. For this reason, a general player hits the ball 2 on the face around the sweet spot SS. That is, the position (hit point) at which the ball 2 is hit on the face surface varies.

FIG. 3 is a schematic diagram of a golf club for explaining the direction of variation of the hit points, and shows a state in which hit points on the face surface of a general iron vary. Referring to FIG. 3, in the golf club, a lie angle θ, which is an angle formed by the center axis of the club shaft with respect to axis 4 that is horizontal to the ground, is set. The golf club 3 shows a state in which the lie angle θ is set to the set value in the address state before hitting the ball.
b. Usually, the lie angle θ is 56 ° with a driver.
Around 58 ° with 3 irons, 60 with 6 irons
The angle is set to around 62 ° with a 9 iron.
That is, the lie angle θ is set to increase as the number increases.

However, when the golfer normally addresses the golf club, the lie angle θ may not be equal to the set value because of the variation in the height and the attitude of the golfer. For example, some golfers may hold the toe side floating to prevent duffling. The golf club 3a shows such a state. Also,
The lie angle θ may be larger than the set value depending on how the golfer is held. The golf club 3c shows such a state. Thus, the lie angle θ varies depending on the golfer.

In this case, the hit point (the position at which the ball is hit) on the face surface of the golf club head also varies. Specifically, in the case of the golf club 3a, the ball is hit at a hit point located on the heel side of the club head and below the sweet spot. In a state like the golf club 3c, the ball is hit at a position higher than the sweet spot and located on the toe side of the club head. The direction in which the hit points vary on the face surface of the club head can be approximately represented by a straight line 5 shown in FIG. Here, the axis 4 is a straight line that passes through the center of gravity of the club head and is parallel to the line of intersection of the face surface, which is the face reference surface of the club head, with the ground. Also, assuming a vertical axis that passes through the center of gravity of the club head and is perpendicular to the ground,
The straight line 5 is a straight line passing through the center of gravity of the club head and perpendicular to the center axis of the shaft in a plane defined by the vertical axis and the axis 4. The angle θ ′ between the straight line 5 and the axis 4 is expressed as (90−θ) ° on the paper surface of FIG. 3 (on the plane defined by the vertical axis and the axis 4).

The angle between the projection line and the axis 4 when the straight line 5 which is the direction of the variation of the hit points is projected onto the face surface of the club head is tan ^-1 (tan (90-90
θ) / cos δ). Here, δ indicates the loft angle δ.

More specifically, as shown in FIG. 4, the lie angle θ is 58 ° for the third iron, so that the angle θ ′ between the straight line 5 indicating the direction in which the hit point varies and the axis 4 is 32 °. Becomes Further, as shown in FIG. 5, in the case of a 6-iron, the lie angle θ is 60 °, and the angle θ ′ between the straight line 5 indicating the direction in which the hit point varies and the axis 4 is 30 °. Here, FIG. 4 is a schematic diagram for explaining the variation direction of the hit points on the third iron, and FIG. 5 is a schematic diagram for explaining the variation direction of the hit points on the sixth iron.

It can be seen that the lie angle θ changes as the iron count increases, thereby changing the angle θ ′ between the axis 4 and the direction in which the hit points vary in the golf club.

The inventors set the inertial ellipsoid of the golf club head through the center of gravity of the golf club head and the face reference surface of the golf club head with respect to the variation direction of the hit point obtained as described above. By aligning the major axis of the cut elliptical surface obtained when cutting with a plane parallel to the same direction in almost the same direction, it is possible to improve the directionality of the hit ball and reduce the variation in flight distance. I found it. This will be specifically described below.

First, the inertial resistance in a direction perpendicular to the face reference plane of the golf club is determined. FIG. 6 is a schematic diagram for explaining the inertial ellipsoid and the XYZ axes of the club head. FIG. 6 shows a state in which the golf club is arranged on the ground such that the lie angle and the loft angle are at predetermined angles. Referring to FIG. 6, an axis passing through the center of gravity G of club head 1 and perpendicular to the ground is defined as a Z axis. An axis parallel to the intersection line between the face reference plane and the ground, perpendicular to the Z axis, and passing through the center of gravity G is defined as an X axis. An axis perpendicular to both the X axis and the Z axis and passing through the center of gravity G is defined as a Y axis.

Next, referring to FIG. 7, the direction vector of a plane parallel to the face reference plane and passing through the center of gravity G is represented by f (l,
m, n) ^T. Next, as shown in FIG. 7, vectors f ₁ , f ₂ , and f ₃ shown in the following equations are defined. Here, FIG. 7 is a schematic diagram for explaining the cut ellipsoid and the coordinate conversion.

F ₁ (l ₁ , m ₁ , n ₁ ) ^T = f × Z (0,0,1) ^T f ₂ (l ₂ , m ₂ , n ₂ ) ^T = f ₁ × f (1) f ₃ (l ₃ , m ₃ , n ₃ ) ^T = f ₁ × f ₂ where × represents an outer product.

Next, as shown in FIG. 8, the axis parallel to the intersection of the face reference plane and the ground and passing through the center of gravity G is the α axis, and the center of gravity G is perpendicular to the α axis on this face reference plane. Let the axis passing through be the β axis. An axis perpendicular to both the α axis and the β axis is defined as a γ axis. Here, the relationship between the XYZ coordinate system and the αβγ coordinate system is expressed as follows.

X = l ₁ · α + l ₂ · β + l ₃ · γ Y = m ₁ · α + m ₂ · β + m ₃ · γ (2) Z = n ₁ · α + n ₂ · β + n ₃ · γ where l ₁ and l ₂ , l ₃ , l ₁₂ , l ₁₃ and l ₂₃ are represented by X, Y,
When the moment of inertia about the Z axis and the product of inertia are used, the inertial ellipsoid 6 of the club head 1 is represented by the following equation.

L ₁ · X ² + l ₂ · Y ² + l ₃ · Z ² + 2 · l ₁₂ · X · Y + 2 · l ₁₃ · X · Z + 2 · l ₂₃ · Y · Z = 1 (3) The inertial ellipsoid 6 represented by the equation (3) is XY
Expressed in the Z coordinate system. The inertial ellipsoid 6 indicates the magnitude of the inertial resistance in each direction. By substituting equation (2) into equation (3), the inertial ellipsoid 6 can be represented using the αβγ coordinate system. Furthermore, this αβ
In the equation of the inertial ellipsoid represented by the γ coordinate system, if the term of γ is set to 0, the equation of the cut ellipsoid 7 obtained by cutting the inertial ellipsoid 6 by a plane parallel to the face reference plane passing through the center of gravity G is obtained. You can ask. Equation (4) of the cut ellipsoid is expressed as follows.

(I₁l₁ ^Two+ I_Twom₁ ^Two+ I_Threen₁ ^Two+ I₁₂l₁m₁+ I₁₃l₁n₁+ I_{twenty three}m₁n₁) Α^Two + (I₁l_Two ^Two+ I_Threem_Two ^Two+ I_Threen_Two ^Two+ I₁₂l_Twom_Two+ I₁₃l_Twon_Two+ I_{twenty three}m_Twon_Two) Β^Two + (I₁l₁l_Two+ I_Twom₁m_Two+ I_Threen₁n_Two+ I₁₂l₁m_Two+ I₁₂l_Twom₁+ I₁₃l₁n _Two ) + I₁₃l_Twon₁+ I_{twenty three}m₁n_Two+ I_{twenty three}m_Twon₁) Αβ = 1 (4) With reference to FIGS.
And a shaft 9a. Here, FIG. 8 illustrates a cut ellipsoid.
FIG. 9 is a schematic view for illustrating a major axis of a cut ellipsoid.
Schematic diagram for explaining an angle θ1 which is an inclination angle between the angle α and the α axis
FIG. 10 is the side of the golf club head shown in FIG.
It is an area schematic diagram.

The size of the cut elliptical surface 7 indicates the magnitude of the inertial resistance indicating the ease of rotation of the club head 1 on the cut surface. That is, this cut ellipsoid 7
Represents the inertial resistance of the club head 1 in the direction perpendicular to the face reference plane. As shown in FIGS. 8 and 9, the major axis length of the cut elliptical surface is indicated by a, and the minor axis length of the cut elliptical surface 7 is indicated by b. From the definition of the inertial ellipsoid, the inertial resistance of the club head 1 is large in the direction along the axis 9b. For this reason, when the hit points vary in the direction along the axis 9b, the displacement of the club head 1 when hitting the ball is minimized. That is, if the major axis 9b of the cut elliptical surface can be aligned in the direction of variation of the hit points on the club head, the rotation of the club head 1 can be minimized even when the hit points vary. As a result, the direction in which the hit ball flies can be improved, and the flight distance can be stabilized.

Here, the direction in which the hit points in the club head 1 vary as described above is the direction indicated by the straight line 5 as shown in FIG. Then, an angle formed between a projection straight line (a straight line indicating the direction in which the hitting points vary) and the α axis when a straight line 5 indicating the direction in which the hitting points vary is projected on a plane passing through the center of gravity G of the club head 1 and parallel to the face reference plane. (Projection variation angle) is tan ^-1 (tan
(90−θ) / cosδ). Here, δ indicates the loft angle.

For example, in the case of the 3-iron shown in FIG. 4, the projection variation angle is 33.6 °. In the case of the 6-iron shown in FIG.
3.7 °.

Therefore, if the major axis 9b of the cut ellipse 7 is set so that the angle θ1 is in the range of 0 ° to 45 °, the direction in which the hit points vary and the major axis 9b of the cut ellipse 7 Can be made substantially the same. As a result, even when the hit points vary, the directionality of the hit ball can be maintained satisfactorily, and the variation in flight distance can be reduced.

When an actual golfer, such as a beginner, uses a golf club, the lie angle θ may not be equal to the set value due to variations in the height and attitude of the golfer. In particular, in the case of a beginner, the variation of the hit points becomes larger in the toe-heel direction of the club head 1 due to the wobbling of the upper body. For this reason, the direction in which the hit points vary is closer to horizontal. In such a case, it is preferable that the angle θ1 formed by the α axis and the major axis 9b of the cut elliptical surface 7 be 0 ° or more and 30 ° or less. In a golf club head corresponding to a beginner having a large body wobble as described above, the angle θ1 is set to 0 °.
It is more preferable to set the angle to 15 ° or less.

FIG. 11 is a schematic view showing the principal axis of the inertia ellipsoid of the golf club head.
2 shows principal axes 8a to 8c of the inertial ellipsoid 6 of FIG. Also,
FIG. 12 is a schematic view showing the major axis and the minor axis of the cut elliptical surface of the golf club head, and shows the cut elliptical surface 7 of the inertial ellipsoid 6 in the club head 1 shown in FIG. In FIG. 12, the major axis 9b and the minor axis 9 of the cut ellipsoid 7 are shown.
a is shown. Here, the shape of the cut ellipsoid 7 is
When the shape of the inertial ellipsoid 6 is made constant, it can be changed by changing the face reference plane of the club head 1. That is, it can be seen that the directions of the main axes 8a to 8c of the inertial ellipsoid 6 and the major axis 9b and the minor axis 9a of the cut ellipsoid 7 can be adjusted independently.

For this reason, the direction of the major axis 9b of the cut elliptical surface 7 shown in FIG.
b and the principal axis 8 of the inertial ellipsoid 6
By adjusting the directions of a to 8c (see FIG. 11),
It is possible to reduce the horizontal deflection of the club head 1 when hitting a ball. Specifically, the principal axes of inertia 8a to 8c of the inertial ellipsoid 6 (see FIG. 11) are projected on an XZ plane defined by the X axis and the Z axis shown in FIG.
By reducing the angle between one of the projected principal axes of inertia and the X axis, the moment of inertia of the club head 1 in the left-right direction can be increased. More specifically, as shown in FIG.
It is preferable that the angle between a and 10b and the X axis is 0 ° or more and 9 ° or less. Here, FIG. 13 is a schematic diagram for explaining the relationship between the angle between the main axis of the inertial ellipsoid projected on the XZ plane and the X axis.

In this way, the major axis 9 of the cut elliptical surface 7
The direction of the hit ball is improved by adjusting the direction of b, and by setting the direction of the axis projected onto the XZ plane and the direction of the X axis as described above by adjusting the direction of the principal axis of the inertial ellipsoid 6,
In addition, variations in flight distance can be reduced.

[0059]

Example 1 A golf club using a club head according to the present invention and a golf club using a conventional club head as a comparative example were tested for variations in ball flight distance with respect to variations in hit points. Was.
A golf club according to the present invention includes a club head according to the present invention and a shaft connected to the club head. A conventional golf club also includes a club head and a shaft. In the golf club head according to the present invention used in this test, a 3 iron having a loft angle δ of 20 ° and a lie angle θ of 58 ° was used. The angle θ1 between the major axis 9b (see FIG. 9) and the α-axis (see FIG. 9) of the cut elliptical surface of the inertial ellipsoid in the club head according to the present invention was set to 8 °.

As the test conditions, the speed of the golf club head was set to 37 m / sec by a golf robot. Then, in consideration of the variation of the hit points when a normal golfer used, the flight distance was measured at three hit points as shown in FIG. FIG. 14 is a schematic diagram for explaining the spots during the test in the first embodiment. Specifically, referring to FIG. 14, a hit point 13 corresponding to a sweet spot and a hit point 11 located on the toe side (on the toe)
And the hit point 12 located on the heel side (under the heel). The hit points 11 to 13 are 8 ° with respect to the α axis.
And the distance between the hit points was 12 mm. Table 1 shows the measurement results.

[0061]

[Table 1]

As can be seen from Table 1, in the golf club using the conventional club head, the hit point 1 on the toe side
In No. 1, the flight distance of the ball was significantly reduced. However, in the golf club using the club head according to the present invention, the flight distance at the hit point 11 with respect to the hit points 12 and 13 is less reduced than in the conventional club head. This indicates that the rotation of the head at the time of impact is suppressed in the club head of the present invention as compared with the conventional club head. Further, in the golf club using the club head according to the present invention, the directionality of the hit ball is more stable than that of the conventional club.

As described above, in the club using the club head according to the present invention, it is understood that the directionality of the hit ball can be improved and the variation in the flight distance can be reduced.

(Embodiment 2) FIG. 15 is a schematic view showing Embodiment 2 of a golf club head according to the present invention. FIG.
, The iron club head 1 is divided into a shaft insertion portion and a face portion. And club head 1
Defined by an X axis and a Y axis passing through the geometric center of
The face part is divided by a plane (horizontal plane) parallel to the Y plane (see FIG. 6). Further, the face portion is divided by a plane (vertical plane) parallel to a YZ plane (see FIG. 6) defined by the Z axis and the Y axis. Further, the club head 1 is divided into a face side and a back side. In this way, as shown in FIG. 15, the club head 1 is moved to the areas a1 to i1 and a2.
Is divided into 18 areas, i. And the area c1
And a metal having a relatively large specific gravity are arranged at h1 and h1. As the metal, for example, a stainless alloy, a tantalum alloy, a tungsten alloy, or the like can be used. As a result, the angle θ1 between the major axis 9b of the cut ellipsoid and the α-axis can be set to 8 ° as shown in Table 2.

As another example of the second embodiment, as shown in FIG. 16, a metal having a relatively lower specific gravity than other regions is arranged in regions a1, d1, and i1. As this metal, for example, a stainless alloy, a lithium alloy, a beryllium alloy, an aluminum alloy, a titanium alloy, or the like can be used. Here, FIG. 16 is a schematic diagram showing another example of Embodiment 2 of the golf club head according to the present invention. By doing so, as shown in Table 2, the angle θ2, which is the inclination angle between the major axis 9b of the cut ellipsoid and the α-axis, is 25
°.

[0066]

[Table 2]

Also, using the material arrangement as shown in FIG. 15, the third iron (3I) and the sixth iron (6I)
And were produced. Table 3 shows data such as dimensions of the manufactured 3rd iron and 6th iron.

[0068]

[Table 3]

As described above, by appropriately selecting the material for each region of the club head 1, the weight balance of the club head 1 can be changed. As a result, the angle between the major axis 9b of the cut elliptical surface 7 of the club head 1 and the α-axis can be changed.

In the golf club set including the golf club having the club head according to the present invention, the angle range in which the angle θ1 between the major axis 9b of the cut ellipsoid and the α axis is selected as the club number increases. It may be larger.

In the golf club set including the golf club having the club head according to the present invention, the angle θ1 between the major axis 9b of the cut elliptical surface and the α-axis is set to increase as the club number increases. May be.

Further, in the golf club head according to the present invention, iron, stainless steel, aluminum, titanium,
Magnesium, tungsten, copper, nickel, zirconium, cobalt, manganese, zinc, silicon, tin, chromium, FRP, synthetic resin, ceramics, rubber, and the like can be used. Further, the above-mentioned materials may be used as a single material, or a club head may be manufactured by combining two or more kinds of the above-mentioned materials.

As a method of manufacturing a club head according to the present invention, a precision casting method may be used. If this precision casting method is used, a low cost and high dimensional accuracy club head can be obtained.

The club head body may be formed by die casting, press molding, or forging. Further, the club head may be divided into a plurality of parts, and each part may be manufactured by press working, forging, precision casting, metal injection, die casting, cutting, or powder metallurgy. The respective parts may be joined by a method such as welding, bonding, press-fitting, fitting, crimping, screwing or brazing to produce a club head.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the embodiments and examples, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0076]

As described above, according to the present invention, the inclination of the long axis of the cut elliptical surface with respect to the reference axis in the club head is defined, thereby improving the directionality of the hit ball and improving the flying performance. A golf club head, a golf club, and a golf club set capable of reducing variation in distance can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a golf club head.

FIG. 2 is a schematic side view of a golf club head.

FIG. 3 is a schematic diagram of a golf club for describing a direction in which hit points vary.

FIG. 4 is a schematic diagram for explaining a direction of variation of hit points in a third iron.

FIG. 5 is a schematic diagram for explaining a variation direction of hit points in a 6-iron.

FIG. 6 is a schematic diagram for explaining an inertial ellipsoid and XYZ axes of a club head.

FIG. 7 is a schematic diagram for explaining a section ellipse and coordinate transformation.

FIG. 8 is a schematic diagram for explaining a cut ellipsoid.

FIG. 9 is a schematic diagram showing an angle between a long axis and an α axis on a cut ellipsoid.

10 is a schematic side view of the golf club head shown in FIG.

FIG. 11 is a schematic diagram showing a main axis of an inertial ellipsoid of a golf club head.

FIG. 12 is a schematic diagram showing a major axis and a minor axis of a cut elliptical surface of a golf club head.

FIG. 13 is a schematic diagram for explaining the relationship between the angle between the main axis of the inertial ellipsoid projected on the XZ plane and the X axis.

FIG. 14 is a schematic diagram for explaining hit points during a test in Example 1.

FIG. 15 is a schematic view showing Embodiment 2 of the golf club head according to the present invention.

FIG. 16 is a schematic view showing another example of the second embodiment of the golf club head according to the present invention.

[Explanation of symbols]

1 club head, 2 balls, 3, 3a to 3c club, 4 axes, 5 straight lines, 6 inertia ellipsoid, 7 cut ellipsoid, 8a to 8c principal axes of inertia ellipsoid, 9a, 9b axes of cut ellipse, 10a, 10b Axis where the principal axis of inertia is projected on the XZ axis, 11 to 13 hit points.

Claims (7)

[Claims] 1. A golf club according to claim 1, wherein said golf club head is a golf club head having a golf club head and a golf club head. A golf club head, wherein the inclination angle of the major axis of the cut ellipsoid obtained when the inertia ellipsoid of the club head is cut is 0 ° or more and 45 ° or less in the toe-up direction. 2. The golf club head according to claim 1, wherein the inclination angle is 0 ° or more and 30 ° or less. 3. The golf club head according to claim 1, wherein the inclination angle is 0 ° or more and 15 ° or less. 4. An axis passing through the center of gravity and perpendicular to the ground is defined as a Z-axis, an axis parallel to the intersection line and passing through the center of gravity is defined as an X-axis, and one of main axes of the inertial ellipsoid is defined as the Z-axis. The golf club head according to any one of claims 1 to 3, wherein an angle formed between the main axis projected onto a plane defined by an axis and the X axis and the X axis is 0 ° or more and 9 ° or less. . 5. A golf club comprising: the golf club head according to claim 1; and a shaft having one end connected to the golf club head. 6. A golf club set including the golf club according to claim 5, wherein the golf club includes a first golf club and a second golf club having a higher count than the first golf club. The inclination angle of the first golf club is selected from a first angle range, and the inclination angle of the second golf club is selected from a second angle range larger than the first angle range. Golf club set to be selected. 7. The golf club set according to claim 6, wherein the inclination angle of the second golf club is greater than or equal to the inclination angle of the first golf club.