JP2000140166A - Golf club head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To firmly assure the stability of the directivity of an impacted ball even in case of the occurrence of duffing by setting the inertia moment around the centroid of golf club head to specific value. SOLUTION: A head body 1 of a wood type is formed to a hollow shape by a shell member having a top 1a, back 1b, sole 1c, face 1d, toe 1e and heel 1f. In such a case, projecting parts 1a', 1c' and 1e' are formed in the inner peripheral parts of the top 1a, sole 1c and toe 1e of the shell member so as to enclose the position G which is ought to be the centroid when the head body is constituted. As a result, the inertia moment around the centroid G is made to >=2600 g/cm2 and the rotation around the centroid G in case of the occurrence of duffing is suppressed. Namely, the change in the direction of the face is lessened at the time of impact and the directivity of the hit ball is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a golf club head.

[0002]

2. Description of the Related Art Conventionally, it has been an issue for golf players to overcome a missed shot such as a slice or a hook ball when not hitting a ball at a sweet spot. As means for solving such a problem, it has been practiced to increase the moment of inertia of the golf club head in the toe / heel direction, thereby making the head difficult to rotate and stabilizing the direction. That is, various improvements have been made to increase the moment of inertia about the center of gravity as viewed from the top side, so that the golf club has a head (face surface) that is difficult to face left and right.

[0003] On the other hand, mistakes at the time of hitting a ball include a so-called "duffling", in which the head collides with the ground immediately before hitting the ball, in addition to the above-mentioned ones. Such a duffry,
It is a phenomenon that occurs immediately before impacting the ball, and if such a duffling occurs, it is no longer possible to control the direction of the head, so as a golf club head to minimize the decrease in head speed, The sole shape is devised so that it is easy to slip through.

[0004] However, the head that once collides with the ground due to "duffling" rotates in the circumferential direction of the head viewed from the face side around the center of gravity by the force received from the ground, and the rotation causes the face to have a loft angle or a curvature (bulge). , Roll), the direction of the face is changed and the direction of the hit ball is deteriorated. In other words, when a duffling occurs on the heel side of the head, the toe side of the head is lowered by the reaction force, and when impacting in this state, the ball is likely to jump rightward because the face is facing right due to the loft angle. . Conversely, if duffling occurs on the toe side of the head, the reaction force will lower the heel side of the head, and when impacted in this state, the ball is likely to jump leftward because the face is facing left due to the loft angle. Become. The duffling that occurs when the toe / heel side collides with the ground is an upright swing in which the toe side of the head is lowered due to a swing error, ground conditions, or a difference in height, and a flat swing in which the heel side of the head is lowered. Easily caused by

Conventionally, no consideration has been given to the moment of inertia in the circumferential direction of the head centered on the center of gravity as viewed from the face side when designing a golf club head. When
It is the present situation that the directionality of the hit ball is deteriorated.

It is an object of the present invention to provide a golf club head which can stabilize the directionality of an impacted ball even if "duffing" occurs.

[0007]

SUMMARY OF THE INVENTION In a golf club,
As shown in FIG. 1, “duff” when swinging is a position vertically below the center of gravity G as viewed from the face side (point P).
In addition to the collision of the sole with the ground, the toe or heel of the head is lowered due to the difference in height of each player, the habit of the swing, etc., and as shown in FIGS. There are cases where collision occurs at positions shifted in the heel direction (points P1 and P2). Such P1 point, P
When the sole collides with the ground at two points, the head receives R1, R indicated by arrows in FIG.
A force acts in two directions (the circumferential direction of the head around the center of gravity as viewed from the face side), and the head attempts to rotate in this direction.

The face of the head has a loft angle. When the face portion of the head rotates in the direction of the arrow in FIG. 1 at the moment of impact with the ball, the face at the time of impact is left and right due to the loft angle and curvature. Would be suitable for Specifically, when the head duffs at point P1, the head rotates in the direction of R1 due to the force received from the ground,
If an impact is made in this state, the ball is likely to emerge to the left. Conversely, when the head duffs at point P2, the head rotates in the direction of R2 due to the force received from the ground, and when impacted in this state, the ball is more likely to come out to the right.

The inventor of the present invention has found out the phenomenon described above with respect to "duffling" of a golf club, and by configuring the head as described below, the directionality can be improved even if "duffling" occurs. did. (1) A head is prepared such that the moment of inertia in the circumferential direction of the head around the center of gravity as viewed from the face side is 2600 g · cm ² or more.

[0010] The moment of inertia of the conventional golf club head is, on average, are set to be substantially 1700~2200g · cm ^2, it is also 2400g · cm ² about the largest ones. On the other hand, by forming the head so that the moment of inertia is further increased, it is possible to suppress the rotation in the circumferential direction around the center of gravity during duffling. The following experiment was conducted on the effect of the directionality of a golf club head having a large moment of inertia.

A large number of wood club heads are prepared (prepared every 200 g · cm ² ) in which the above-mentioned moment of inertia is set to various values (the conditions other than the moment of inertia are all the same), and each of the heads is hit by a robot ( The head speed is 40 m / s when no duffing is performed), and the distance of the shake from the center to the left and right is measured. In this measurement, in order to make the state of “duff” the same in all test clubs, as shown in FIG. 4A, the swing was set so as to duff at 150 mm before the ball, and the duff state was also A duffed state on the heel side of the sole (tilt the shaft at −15 degrees with respect to the normal lie angle; see FIG. 4B), and a duffed state on the toe side of the sole (with respect to the normal lie angle) The shaft was tilted by +15 degrees; see FIG. 4 (d)), and 20 hits each, for a total of 40 hits (FIG. 4 (c) shows the attitude of the head when there is no duff). Then, when the average value of the distances deviated left and right from the center was obtained, the following results were obtained.

[0012]

[Table 1]

As is clear from this measurement, the conventional head formed so that the moment of inertia in the circumferential direction of the head centered on the center of gravity as viewed from the face side is 2400 g · cm ² or less, as in the prior art. By forming the head such that the moment of inertia is 2600 g · cm ² or more as in the present invention, a remarkable improvement in directionality is observed. The result that blurring hardly occurs was obtained. As is clear from the measurement results, the directionality is stabilized when the moment of inertia is increased, but when the moment is too large, the balance of the entire head is lost. Therefore, the upper limit is set to about 3400 g · cm ^2. It is preferable to keep it. (2) In addition to the above-described setting of the moment of inertia, the head is designed such that when "duffling" actually occurs, rotation of the head in the circumferential direction around the center of gravity can be suppressed as much as possible when viewed from the face side. Thus, the directionality of the ball can be stabilized. That is, the rotation of the head described above
As shown in FIGS. 2 and 3, the sole collides with the ground at positions (P1, P2) shifted in the toe-heel direction with respect to the vertically lower position P of the center of gravity G viewed from the face side. It is also caused by the force received from the ground. Therefore, P,
By forming the sole such that the distance R between P1 and between P and P2 is reduced, it becomes possible to suppress the rotation of the head around the center of gravity G. That is, the contact position with the ground
By forming the sole so as to be as close to the point P as possible, the head can be prevented from rotating in the head circumferential direction as described above.

Specifically, the "duff" in the toe-heel direction occurs when a flat swing as shown in FIG. 2 or an upright swing as shown in FIG. 3 is performed. And "Dafuri" as shown in these figures
Occurs in a range of ± 15 degrees with respect to the lie angle α at the time of normal addressing shown in FIG. For this reason, at the time of addressing, when tilted by 15 degrees in the toe direction and the heel direction, the distance between the vertical line passing through the center of gravity G and the ground point (P1, P2) of the ridge line of the sole viewed from the face side is reduced. By forming the sole on the head, even when the head is actually duffed, the rotation of the head around the center of gravity G can be suppressed, and the directionality can be stabilized.

In a conventional golf club head, when the shaft is inclined ± 15 degrees with respect to a regular lie angle when viewed from the face side, the distance between the vertical line passing through the center of gravity and the contact point between the ridge line of the sole and the ground is the average. It is set to approximately 10 to 20 mm,
The smallest one is about 3.6 mm. On the other hand, by forming the sole such that the distance R is reduced, it becomes possible to suppress rotation around the center of gravity even when a force acts from the ground. Thus, between P and P1 described above,
The following experiment was conducted on the effect of the directionality of a golf club head having a sole formed so as to reduce the distance R between P and P2.

As in the experiment (1), P, P
1 and the distance R between P and P2 were variously changed (1.0 mm
A number of wood club heads having a sole shape (changed every time) (inertial momentum in the circumferential direction of the head is set to 2200 g · cm ² ) are prepared in a large number, and each of them is hit by a robot (head speed is 40 m / s when no duffing is performed). Then, measure the distance of the shake from the center to the left and right. Also in this measurement, as shown in FIG. 4A, the swing was set so as to duff at 150 mm before the ball,
In addition, a state in which the sole is deflated on the heel side (see FIG. 4B) and a state in which the sole is torched on the toe side (FIG. 4B)
(See (d)), and 20 hits each, for a total of 40 hits (when R = 0, 40 hits). Then, when the average value of the distances deviated left and right from the center was obtained, the following results were obtained.

[0017]

[Table 2]

Thus, as compared with the conventional head in which the sole is formed so that the distance of R is about 3.6 mm, as in the present invention, the distance of R is 2.6 mm or less. By forming the sole on the base, a remarkable improvement in the directionality was observed. In such a configuration, the shape of the sole is specified by the ridgeline viewed from the face side, and the shape in the face-back direction is not limited. Further, the shape of the sole is preferably formed symmetrically with respect to a vertical line passing through the center of gravity when viewed from the face side, but may be any other shape. Further, between P and P1 described above and between P and P2
When the distances between the two are different in size, the larger one is set as the R distance.

As described in (1) above, a preferable effect can be obtained by forming the head so that the rotational moment around the center of gravity is large. However, the shape of the sole is such that R is not more than 2.6 mm. If it is formed, the rotational moment around the center of gravity is set to at least 2400 g · cm ² or more in consideration of a decrease in the moment of force around the center of gravity received from the ground when the head is duffed, and the like. Preferably.

Alternatively, as described in (1) above, according to the golf club in which the moment of inertia around the center of gravity of the head is set to 2600 g · cm ² or more, it is possible to suppress the rotation of the head when duffing. . For this reason, if the head is configured in combination with the technique (1), R is set to the value of the conventional head in consideration of the difficulty of rotation of the head when the head is duffed due to the magnitude of the moment of inertia. Preferably, the sole shape is 10 mm or less, which is smaller than the average range. (3) The moment of inertia described above, and between P and P1, P,
It is also possible to configure the head in consideration of the sole in which the distance R between P2 is reduced. That is, when the duffling occurs, the rotation around the center of gravity of the head can be suppressed by suppressing the angular acceleration β generated in the direction of the arrow in FIG. 1 as much as possible. Here, assuming that the moment of inertia is I and the force that the head receives from the ground when duffling occurs is F, a relationship of FR = I · β holds, and a relationship of β = F · (R / I) holds. Is derived. As is apparent from this equation, the angular acceleration β can be adjusted by the value of R / I that changes depending on the configuration of the head. That is, by suppressing the value of R / I, the value of angular acceleration β is also suppressed, and rotation around the center of gravity can be suppressed.

The conventional golf club head has the above-mentioned R
When the value of / I was measured, on average, it was approximately 2.5 to 7.5 × 1.
It is set to 0 ^-4 [1 / (g · cm)], and at least about 1.50 × 10 ^-4 [1 / (g · cm)]. On the other hand, by forming the head so that the value of R / I becomes small, the angular acceleration at the time of duffing can be suppressed, and the rotation of the head in the circumferential direction can be suppressed. Here, various values of R / I are set (0.50 × 10
^-4 [changed every [1 / (g · cm)]), a golf club head equipped with each head was subjected to an experiment similar to the above (1), and the golf club head was displaced from the center to the left and right. When the average value of the distances was obtained, the following results were obtained.

[0022]

[Table 3]

As is apparent from the result, the above-described R
By forming the head such that the value of / I is 1.00 × 10 ⁻⁴ [1 / (g · cm)] or less, the angular acceleration around the center of gravity of the head is effectively suppressed, and Remarkable results were obtained. For this reason, by adjusting the distance of R and the value of the moment of inertia I in a well-balanced manner according to the type of the head and the subject, the rotation of the head is suppressed even if duffling occurs, and the golf club has a stable directionality. It becomes possible. Even in such a configuration, if the rotational moment I around the center of gravity is set to 2600 g · cm ² or more, duffling occurs and even if force is applied from the ground,
According to the magnitude of the moment, a golf club having an effect such as a spinning rotation can be obtained. Or,
By forming the sole so that the distance of R is 10 mm or less, the position of the force received from the ground when the head is duffed becomes close to the center of gravity, and the golf club has an effect that rotation is unlikely to occur. Can be

[0024]

FIG. 5 shows an embodiment of the golf club head according to the present invention constructed on the basis of the above description.
This will be described with reference to FIG. In this embodiment, the center of gravity G
It is an embodiment for increasing the surrounding moment of inertia.

5A shows a wood type head. FIG. 5A is a cross-sectional view of the head body 1 near the center of gravity along the toe-heel direction, and FIG. 5B is the center of gravity of the head body. It is sectional drawing along the face-back direction in the vicinity.

The head body 1 has a top 1a, a back 1
b, sole 1c, face 1d, toe 1e and heel 1
f is formed in a hollow shape by a so-called outer shell member. These members are integrally formed singly or arbitrarily in combination, and are joined by welding or the like, whereby a head as shown in the figure is manufactured. In this case, the material constituting each member is not particularly limited, and for example, titanium, a titanium alloy, stainless steel, an aluminum alloy, a fiber reinforced metal, or the like can be used.

Of the outer shell members as described above, the top 1
Projections 1a ', 1c', 1e 'are formed on the inner periphery of the a, the sole 1c, and the toe 1e so as to surround a position G to be a center of gravity when the head body is constructed.
In this way, by making the inner peripheral portion of the outer shell member thick (weight part) so as to surround the center of gravity G, the rotational moment around the center of gravity G can be increased, and even if duffling occurs, the center of gravity can be obtained. When the rotation around G is suppressed and the impact is actually made, the change in the direction of the face is reduced, and the directionality can be stabilized.

The above-mentioned weight part can be integrally formed with each outer shell member by forging, casting, pressing, or the like, or after each outer shell member is formed, the weight member is placed at a predetermined position. Separately, it can be attached by welding or the like. In the configuration shown in FIG.
Similarly, a protruding portion may be formed so that the weight portion goes around the center of gravity G. In addition, weight part (thick part)
May be formed continuously as shown in the figure or may be formed partially, and the distribution thereof can be implemented in various forms.

Of course, as described above, the head body 1
Has a sole 1c, as shown in FIGS. 2 and 3,
It is more preferable to make the shape such that the distance of R is 10 mm or less. Further, the constituent material of each member, the shape of the head, and the manufacturing method thereof are not limited as long as the requirements described in the claims are satisfied.

[0030]

As described above, according to the present invention, even when the golf club is swung and the head body hits the ground strongly at the time of hitting (when duffling occurs), the direction of the head is hard to change, and the direction of the hitting ball is reduced. The nature becomes stable.

[Brief description of the drawings]

1A and 1B are diagrams for explaining the present invention, in which FIG. 1A is a diagram of a head viewed from the front, and FIG. 1B is a diagram of the head viewed from a side.

FIG. 2 is a view for explaining the present invention, showing a posture of the head when a flat swing is performed (a state where the head is tilted by +15 degrees with respect to a normal lie angle).

FIG. 3 is a view for explaining the present invention, and shows a case where the head is upright-swinged (the head is moved −1 with respect to a normal lie angle).
FIG. 5 is a diagram illustrating a posture of a head in a state of being tilted by 5 degrees).

FIGS. 4A and 4B are diagrams for explaining an experiment of head duffling according to the present invention, wherein FIG. 4A is a diagram for explaining the trajectory of the head, and FIGS. Diagram showing the state of the head when swinging
(C) is a diagram showing the state of the head in a normal swing without duffling.

FIG. 5 is a diagram showing an embodiment of the present invention, wherein (a)
FIG. 4 is a cross-sectional view of the head near the center of gravity along the toe-heel direction, and FIG. 4B is a cross-sectional view of the head near the center of gravity along the face-back direction.

[Explanation of symbols]

1. Head body, 1a top, 1b back, 1c
Sole, 1e ... toe, 1f ... heel, G ... center of gravity.

Claims (8)

[Claims] 1. A golf club head having a moment of inertia in a circumferential direction of a head centered on a center of gravity as viewed from a face side of 2600 g · cm ² or more. 2. The distance between a vertical line passing through the center of gravity and a contact point of the ridge line of the sole viewed from the face side when the head is inclined by 15 ° in the toe direction and the heel direction at the time of addressing is 10 mm.
The golf club head according to claim 1, wherein the sole is formed as follows. 3. The distance between the vertical line passing through the center of gravity and the contact point of the ridge line of the sole viewed from the face side is 2.6 m when tilted by 15 ° in the toe direction and the heel direction at the time of addressing.
m, wherein the sole is formed so as to be not more than m. 4. The golf club head according to claim 3, wherein a moment of inertia in a head circumferential direction centered on a center of gravity as viewed from the face side is 2400 g · cm ² or more. 5. When the moment of inertia in the circumferential direction of the head centered on the center of gravity viewed from the face side as I is tilted by 15 ° in the toe direction and the heel direction at the time of addressing, respectively, the perpendicular line passing through the center of gravity and the face side are viewed from the face side. When the distance between the ridge line of the sole and the ground contact point is R, R / I is 1.00 × 10
^-4 [1 / (g · cm)] or less. 6. The golf club head according to claim 5, wherein I is 2600 g · cm ² or more. 7. The golf club head according to claim 5, wherein R is 10 mm or less. 8. When the moment of inertia I in the circumferential direction of the head around the center of gravity as viewed from the face side is 2600 g · cm ² or more, and the head is inclined by 15 ° in the toe direction and the heel direction at the time of addressing, it passes through the center of gravity. The distance R between the perpendicular and the contact point of the ridge of the sole viewed from the face side is 2.6 mm.
And R / I is 1.00 × 10 ⁻⁴ [1 / (g ·
cm)] or less.