JP2001017585A - Head for wood golf club - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head for a wood golf club which is hard to cause a slice. SOLUTION: This head 1 for a wood type golf club has a bulge 3 on the face surface to hit a ball. When the face surface is virtually divided into a heel side h and a toe side t by a first virtual dividing line which vertically passes a sweet spot point SS wherein a normal line N drawn on the face surface 2a from the center G of gravity of the head 1, crosses the face surface 2a, in the toe side bulge surface 3t and the heel side bulge surface 3h, the bulge radius Rto on a horizontal surface passing the sweet spot point SS, of the toe side bulge surface 3t is set to be 1.2 to 4.0 times of the bulge radius Rho of the heel side bulge surface 3h on the horizontal surface.

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 for a wood type golf club, which hardly undergoes side spin during slice rotation.

[0002]

2. Description of the Related Art A general wood-type golf club head has a bulge (horizontal face bulge) on a face on which a ball is hit. As shown in FIG. 6, the "bulge" is a horizontal radius of the curvature radius R formed on the face f when the head a is viewed from a plane. The operation of such a bulge is as follows.

As shown in FIG. 5A, when a ball is hit on the toe side of the sweet spot point SS on the face surface with a head having no bulge on the face surface, the head moves from the center of gravity G of the head to the hit position. The moment of the product (F × D1) of the distance D1 and the impact force F due to the impact of the ball acts on the center of gravity G to instantaneously rotate the head about a vertical axis passing through the center of gravity G. The hit ball has a hook effect (hereinafter, “hook”,
"Slice" refers to a right-handed golfer). The “gear effect” is, as shown in FIG. 6, the ball b and the face f
Is a phenomenon in which a side spin of the head b is rotated in a direction opposite to the rotation around the center of gravity G of the head a due to friction at the time of contact with the ball b.

In FIG. 5 (a), since the face has no bulge, the face has a target flight line direction L.
In the case of a square, the ball is hit straight in the eyeball direction L, but immediately deviates to the left more than the target ball direction L by the side spin of the hook rotation. Conversely, when the ball is hit on the heel side of the face surface, the ball is given a side spin of the slice rotation, and conversely, the ball is greatly sliced and deviated to the right more than the target flight line direction L.

On the other hand, as shown in FIG. 1B, in the case of a head provided with a bulge on the face surface, the ball hits on the toe side (the same position as in (a)) above the sweet spot point SS on the face surface. Even if it is performed, the distance D2 from the center of gravity G of the head to the ball hitting position becomes smaller than in the case of (a), and the moment (F × D2) for instantaneously rotating the head also becomes smaller. For this reason, the rotation speed of the head is relatively lower than in the case of (a), the gear effect is reduced, and the side spin amount of the hook rotation given to the ball is also relatively small. Also, because the toe side of the face is slightly rightward due to the bulge,
The trajectory is corrected such that the ball is launched slightly to the right of the target flight line direction L, and returns to the target flight line direction L by the side spin of gentle hook rotation.

Also, when the ball is hit on the heel side of the face surface, the amount of side spin in the slice rotation of the ball can be made relatively small due to a reduction in the gear effect. Also, since the heel side of the face surface is slightly leftward due to the bulge, the ball is launched slightly leftward from the target flying line direction L, and the target flying line is formed by the side spin of the gentle slice rotation. It is possible to return to the direction L.

[0007] Thus, the bulge affects the gear effect. That is, when the radius R of the bulge is reduced and the roundness is increased, the gear effect is reduced. On the contrary, when the radius R of the bulge is increased and the surface is flattened, the gear effect tends to appear strongly.

[0008]

The radius of a conventional bulge is conventionally set to about 220 to 400 mm, and is generally formed to have substantially the same radius from the toe to the heel on the face surface. It is a target. The reason for this is to make the strength of the gear effect due to the bulge constant on each side of the heel and toe of the face surface, and to make the above-mentioned hit ball trajectory correcting function uniform.

However, it is well known empirically that beginner golfers do not have stable hitting points and are likely to produce slice-type hits with side spin of slice rotation. In addition, many golfers tend to prefer a so-called drawball ball having a small degree of bending of the hook ball with a moderate spin rotation of the side spin.

The present invention has been devised in view of the above problems, and is based on the fact that the bulge radius is relatively large on the toe side of the face surface and small on the heel side. When hit on the toe side, the ball gives the ball more side spin for the hook rotation, and even when hit on the heel side, it is difficult to give the ball the side spin of the slice rotation, effectively suppressing the slice. It is an object of the present invention to provide a golf club head.

[0011]

According to a first aspect of the present invention, there is provided a head for a wood type golf club having a bulge on a face for hitting a ball, wherein the head is pulled from the center of gravity of the head to the face. A first imaginary dividing line vertically passing through a sweet spot point at which the normal line intersects the face surface, the toe side, the heel side bulge surface, and the heel side bulge surface, where the face surface is virtually divided into the toe side and the heel side. A bulge radius Rto of the toe-side bulge surface in a horizontal plane passing through the sweet spot point is 1.2 to 4.0 times a bulge radius Rho of the heel-side bulge surface in the horizontal plane.

The bulge radius Rti of the toe-side bulge surface in an arbitrary horizontal plane is 1.2 to 4.0 times the bulge radius Rhi of the heel-side bulge surface in the same horizontal plane. The wood type golf club head according to claim 1, wherein:

According to a third aspect of the present invention, the toe-side bulge radius Rto passing through the sweet spot point is 400 to 400.
3. The wood-type golf club head according to claim 1, wherein the head is 1000 mm.

According to a fourth aspect of the present invention, the face surface has a roll, and the face surface is virtually divided into a crown side and a sole side by a second virtual division line passing right and left through the sweet spot point. Between the crown-side roll surface and the sole-side roll surface, the roll radius Rco of a vertical surface passing through the sweet spot point of the crown-side roll surface is defined as a roll radius Rso of the vertical surface of the sole-side roll surface. The wood type golf club head according to any one of claims 1 to 3, wherein the ratio is 1.2 to 4.0 times.

According to a fifth aspect of the present invention, the roll radius Rci on any vertical surface of the crown side roll surface is equal to the roll radius Rsi on the same vertical surface of the sole side roll surface.
The wood type golf club head according to claim 4, wherein the ratio is 1.2 to 4.0 times.

According to a sixth aspect of the present invention, there is provided a roll radius Rc of a crown-side roll surface passing through the sweet spot point.
6. The wood type golf club head according to claim 4, wherein o is 400 to 1000 mm.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a front view of a wood type golf club head (hereinafter, may be simply referred to as a “head”) 1 of the present embodiment. In the figure, head 1
A face 2a which hits a ball and has a predetermined loft angle; a crown 2b which is continuous with an upper edge of the face 2a and forms an upper surface of the head 1;
a sole portion 2c continuing from the lower edge of the head portion 1 and forming the lower surface portion of the head 1; and a side extending between the crown portion 2b and the sole portion 2c from the toe t on the face surface to the heel h of the face surface 2a through the back face. It has a portion 2d and a shaft mounting portion 2e to which the shaft is attached. The head 1 of this example is made of metal having a head volume of about 220 to 320 cc and a depth of the center of gravity (horizontal distance between the center of gravity G of the head and the lower edge of the face surface) of about 21 to 46 mm. Is illustrated.

The face 2a of the head 1 is formed as a curved surface which is smoothly convex outward, and in this embodiment, the bulge 3 and the roll 4 are shown.
The bulge 3 moves the face surface 2a to the center of gravity G of the head.
A normal line N (shown in FIG. 2 and FIG. 3) drawn on the face surface 2a from the toe side by a first virtual dividing line L1 vertically passing through a sweet spot point SS intersecting with the face surface 2a.
It includes a toe-side bulge surface 3t and a heel-side bulge surface 3h when virtually divided on the heel side.

As shown in FIGS. 1 and 2, the bulge radius Rto of the toe-side bulge surface 3t on the horizontal plane HP passing through the sweet spot point SS is defined by the heel-side bulge surface 3h of the horizontal plane HP. 1. Bulge radius Rho
It is set to 2 to 4.0 times. In FIG. 2, a part of the head 1 has a cross section along the horizontal plane HP.

In such a head 1, since the bulge radius Rto on the toe side is relatively large, the gear effect is relatively enhanced on the toe side. Therefore, when the ball is hit on the toe side of the sweet spot point SS, the side spin amount of the hook rotation can be increased. Particularly for beginners and the like, the face 2 is often slightly more open than the square at the moment of hitting the ball. Therefore, the ball is easily hit rightward. Then, even if the ball is hit in such a state, the side spin of a large amount of hook rotation is given to the ball to suppress it in the right direction of the hit ball, and the trajectory can be effectively corrected.

In the head 1 of this embodiment, the bulge radius Rho on the heel side of the face surface 2 is relatively small, so that the gear effect is weakened on the heel side. Therefore, even when the ball is hit on the heel side of the sweet spot point SS, an increase in the side spin of the slice rotation is suppressed. Thus, the present invention can provide a head in which side spin of slice rotation is less likely to occur.

Here, the bulge radius Rto on the toe side is obtained.
Needs to be set to 1.2 to 4.0 times the heel-side bulge radius Rho in the horizontal plane HP. If the toe side bulge radius Rto is less than 1.2 times the heel side bulge radius Rho, it becomes difficult to appropriately increase the side spin of the rotation of the hook on the ball launched on the toe side, and The effect of suppressing the side spin amount by the slice rotation of the ball hit on the side also tends to decrease. Conversely, the toe-side bulge radius Rto is
When it exceeds 4.0 times the heel-side bulge radius Rho,
The shape of the face surface 2a becomes unusual, giving the user a sense of incongruity. In addition, the gear effect on the toe side is too strong, giving the ball excessive side spin of the hook rotation, and the roundness of the heel-side bulge surface 3h. It is not preferable because the ball hit on the heel side becomes too strong and tends to hit straight to the left.

From such a viewpoint, the bulge radius Rto on the toe side is equal to the bulge radius Rho on the heel side, which is 1.
It is 2 times or more, more preferably 1.5 times or more, and in combination with any one of the above lower limits, its upper limit is 4.0 times or less, more preferably 3.0 times or less, and further preferably 2 times or less. It is desirable to set it to 0.0 times or less.

It is desirable that the bulge radius Rti of the toe-side bulge surface 3t in an arbitrary horizontal plane is 1.2 to 4.0 times the bulge radius Rhi of the heel side in the same horizontal plane. In other words, it is desirable that the bulge radius Rti on the toe side be 1.2 to 4.0 times the bulge radius Rhi on the heel side on the same horizontal plane even in each horizontal plane having different heights. More specifically, in consideration of a realistic variation in hitting points, for example, 5 mm each on the crown side and the sole side from the horizontal plane HP passing through the sweet spot point SS,
In each horizontal plane between the horizontal plane HP1 on the crown side and the horizontal plane HP2 on the sole side, which is more preferably 7 mm, and still more preferably 10 mm, the bulge radius Rti on the toe side
Is preferably 1.2 to 4.0 times the bulge radius Rhi on the heel side. At this time, it is further preferable that the bulge radius ratio (Rti / Rhi) on each horizontal plane is set to be substantially constant.

Then, for example, the average bulge radius Rta of the toe side bulge surface 3t can be set to 1.2 to 4.0 times the average bulge radius Rha of the heel side bulge surface 3h. The average bulge radius can be calculated, for example, as follows. First, a thin film or the like is stuck on the face surface 2a so as not to wrinkle, and the unevenness such as the score line of the face surface 2a is blinded, and the surface is measured by a three-dimensional shape measuring device at intervals of, for example, 5 mm. Further, as shown in FIG. 4, based on the obtained point group data P,...
3D Bezier curve (Be
zier Curve) and calculate the average value.

If the value of the bulge radius Rto on the toe side passing through the sweet spot point SS is too small, the roundness of the toe-side bulge surface 3t tends to be strong, giving a user an uncomfortable feeling when holding the bulge surface. However, the gear effect at the time of hitting on the toe side tends to decrease, and an appropriate increase in the side spin amount of the hook rotation tends not to be expected. Conversely, if the value of the bulge radius Rto on the toe side is too large, the flatness of the toe-side bulge surface 3t tends to be strong, giving the user a sense of incongruity as described above, and the gear effect when hitting on the toe side is strong. This tends to cause excessive increase in the side spin amount of the rotation of the hook due to excessive rotation. From such a viewpoint, the value of the bulge radius Rto on the toe side of the horizontal plane passing through the sweet spot point SS is:
For example, 200 to 1500 mm, preferably 300 to 12 mm
It is desirable that the thickness be 00 mm, more preferably 400 to 1000 mm.

The head 1 of the present embodiment is provided with a roll (vertical face roll) 4 as shown in FIG. The “roll” is a vertical roundness when the face surface 2 a is viewed from the side.

Generally, since the head 1 has a loft angle, a back-spin is applied to the hit ball.
However, when the ball is hit on the crown c side of the sweet spot point SS on the face surface 2a, the center of gravity G
The head 1 instantaneously rotates about a horizontal axis passing through the ball, a vertical gear effect occurs, and a force acts on the ball to reduce the backspin amount. Conversely, when the ball is hit on the sole s side from the sweet spot point SS on the face surface 2a,
The ball acts to increase the amount of back spin. When a roll is provided on the face surface 2a, such a gear effect is reduced as in the case of a bulge, and a large change in the backspin amount at the time of a miss shot can be suppressed.

The roll 4 of this embodiment is used when the face surface 2 is virtually divided into a crown c side and a sole s side by a second virtual division line L2 (shown in FIG. 1) passing right and left through the sweet spot point SS. As shown in FIG. 4, the sweet spot point SS on the crown-side roll surface 4c includes a crown-side roll surface 4c and a sole-side roll surface 4s.
The roll radius Rco on the vertical plane VP passing through the horizontal plane VP is 1.2 to 4.0 times the roll radius Rso of the sole-side roll surface 4s passing through the horizontal plane VP.

In such a head 1, since the roll radius on the crown side c is relatively large, the gear effect is relatively enhanced on the crown side. Therefore, when the ball is hit on the crown side from the sweet spot point SS,
The effect of reducing the backspin is great. Further, when the ball is hit on the sole side s, the roll radius Rso on the sole side s of the face surface 2a is relatively small, so that the gear effect on the sole side is weakened, and the increase of the back spin is suppressed. . As described above, in the head 1 according to the present embodiment, the increase in the backspin amount can be suppressed as compared with the related art at the time of a miss shot at a hit point deviated vertically from the sweet spot point SS, and This is preferable in that the loss of flight distance due to climbing is minimized.

Here, the crown-side roll radius Rc
o is the roll radius Rso on the sole side in the vertical plane VP.
It is desirable to set the value to 1.2 to 4.0 times. When the crown-side roll radius Rco is less than 1.2 times the sole-side roll radius Rso, the effect of reducing the backspin of the ball launched on the crown side is not sufficient, and the ball is launched on the sole side. It tends to be difficult to suppress an increase in the backspin amount of the ball.

Conversely, the crown-side roll radius Rco
However, if the roll radius Rso on the sole side exceeds 4.0 times, the shape of the face surface 2a becomes peculiar, giving a user a sense of incongruity, and for example, the roundness of the sole side roll surface 4s becomes too strong. In some cases, the ball hit on the sole side may not have a sufficient launch angle.

From such a viewpoint, the roll radius Rco on the crown side is equal to the roll radius Rs on the sole side.
o is 1.2 times or more, more preferably 1.5 times or more, and in combination with any of the above lower limits, the upper limit is 4.0 times or less, more preferably 3.0 times or less, More preferably, it is desirable to set it to 2.0 times or less.

Preferably, the roll radius Rci of the crown-side roll surface 4c on any vertical surface is 1.2 to 4.0 times the roll radius Rsi of the sole-side roll surface 4s on the same vertical surface. . In other words, it is preferable that the roll radius Rci on the crown side be 1.2 to 4.0 times the roll radius Rsi on the sole side on the same vertical plane even in different vertical planes.

More specifically, the vertical plane VP passing through the sweet spot point SS is considered in consideration of a realistic variation of the hit point.
For example, in each vertical plane between the vertical plane VP1 on the toe side and the vertical plane VP2 on the heel side, which is separated by 5 mm, more preferably 10 mm, and more preferably 20 mm on each of the toe side and the heel side, the roll radius Rci on the crown side. Is desirably 1.2 to 4.0 times the roll radius Rsi on the sole side. At this time, the roll radius ratio (R
It is further preferable to set (ci / Rsi) to be substantially constant.

Further, for example, the average roll radius Rca of the crown-side roll surface 4c can be set to 1.2 to 4.0 times the average roll radius Rsa of the sole-side roll surface 4s. The average roll radius can be measured in the same manner as the average bulge radius.

If the value of the crown-side roll radius Rco on the vertical plane VP passing through the sweet spot point SS is too small, the crown-side roll surface 4c tends to be too rounded, and is used when holding the roll. In addition to giving an uncomfortable feeling to the rider, the gear effect when hit on the crown side is reduced, and the effect of reducing the backspin tends to be reduced. Conversely, if the value of the crown-side roll radius Rco is too large,
The flattening of the crown-side roll surface 4c tends to be strong, giving the user a sense of incongruity similarly to the above, and the gear effect when hit on the crown side becomes too strong, and the backspin may be unnecessarily reduced. is there. From such a viewpoint, the value of the crown-side roll radius Rco on the vertical plane VP passing through the sweet spot point SS is, for example, 200 to
It is desirable that the thickness be 1500 mm, preferably 300 to 1200 mm, and more preferably 400 to 1000 mm.

[0038]

EXAMPLE A head having a bulge and a roll having the specifications shown in Table 1 was prototyped, and a wood having the same shaft (Ferject V513 carbon shaft hardness (R) manufactured by Sumitomo Rubber Industries, Ltd.) attached to each head. A golf club was prototyped, and the golf club was set on a swing robot, the ball was hit at a head speed of 45 m / s, and the amount of back spin, side spin, launch angle, and carry of the launched ball were measured. In the test hit test, the following five positions were set as the positions of the face on which the ball was hit, and six balls were hit at each position, and the evaluation was made based on the average value at that time. Base hit point: Sweet spot point Toe side hit point: Position 20mm horizontally on the toe side from the sweet spot point Heel side hit point Sweet spot point heel side horizontally 20mm position crown side RBI from: the sweet spot point crown side perpendicular to the 10mm position sole side RBI from: 10mm position from the sweet spot point on the sole side vertical

Each head was made of a 6Al-4V titanium alloy, the head volume was set to 270 cc, and the loft angle was set to 10 degrees. The launch angle measures the angle of the ball immediately after being launched from the head with respect to the horizontal line, and the side spin measures the number of rotations of the ball immediately after the launch about the vertical axis (hook rotation is indicated by-) using a measuring instrument. did. The carry was defined as a horizontal distance connecting a hitting position of the ball and a position where the ball first dropped by a straight line.
Table 1 shows the specifications of the head, and Tables 2 and 3 show the test results.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

As is clear from the side spin change amount in Table 2, in the golf club of the embodiment, the side spin of the rotation of the hook greatly increased at the toe side hit point.
Conversely, it can be seen that the side spin increase in the slice rotation is small at the heel side hit point. From these results, it can be seen that the golf club head of the present embodiment is difficult to slice and easy to hit a draw ball even at a beginner level.

As is clear from the backspin change in Table 3, in the golf club of the embodiment, the backspin decreases greatly at the crown side hit point, and increases at the sole side hitpoint. It can be seen that the amount is small. From these results, the golf club head of the present embodiment can reduce the backspin of the ball and reduce energy loss due to the backspin, even when hit at a position where the sweet spot is vertically removed. As a result, it was confirmed that the resilience with the ball (ball initial velocity) could be improved, and the blow-up of the hit ball due to the high backspin could be effectively suppressed to suppress the loss of the flight distance.

[0045]

As described above, in the head according to the first to third aspects, the bulge radius on the toe side is relatively large, so that the gear effect is relatively strong on the toe side, and the head effect is higher than the sweet spot point. If you hit the ball on the toe side,
The side spin amount of the hook rotation can be increased. Especially for beginners, the face is often slightly open than the square at the moment of hitting the ball, so that the ball is likely to be launched in the right direction. The side spin of the rotation of the hook suppresses that in the right direction of the hit ball, and the trajectory of the hit ball can be effectively modified.

Further, since the bulge radius on the heel side of the face surface is relatively small, the gear effect is relatively weakened on the heel side, and when the ball is hit on the heel side, the side spin of the slice rotation is reduced. The increase can also be suppressed. As described above, the head according to the present invention is hardly subject to the side spin of the slice rotation.

In the head according to claims 4 to 6, in addition to the above-mentioned effects, since the roll radius on the crown side is relatively large, the gear effect is relatively strong on the crown side, and the crown effect is higher than the sweet spot point. When the ball is hit by the side, the back spin can be further reduced. Further, since the roll radius on the sole side of the face surface is relatively small, the gear effect is weakened on the sole side, and an increase in back spin is suppressed. For this reason, in the case of a miss shot at a hit point deviated vertically from the sweet spot point, in any case, the increase in backspin amount can be suppressed compared to the past, and the loss of flight distance due to the rising of the hit ball is minimized. sell.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing a part of the cross section.

FIG. 3 is a sectional view taken along a first virtual dividing line L1 in FIG. 1;

FIG. 4 is a diagram illustrating an example of measuring an average bulge radius.

5 (a) and 5 (b) are diagrams showing the direction of a flying ball depending on the hitting position of a conventional golf club head and a ball.

FIG. 6 is a plan view of a head for explaining a gear effect.

[Explanation of symbols]

 1 Head 2 Face 3 Bulge 3t Toe-side bulge 3h Heel-side bulge 4 Roll 4c Crown-side roll 4s Sole-side roll SS SS Sweet spot point

Claims (6)

[Claims] 1. A head for a wood-type golf club having a bulge on a face surface for hitting a ball, wherein a normal drawn from the center of gravity of the head to the face surface passes vertically through a sweet spot point intersecting with the face surface. A bulge in a horizontal plane passing through the sweet spot point of the toe-side bulge surface, wherein a toe-side bulge surface and a heel-side bulge surface are obtained by virtually dividing the face surface into the toe side and the heel side by the first virtual dividing line. A wood-type golf club head, wherein a radius Rto is 1.2 to 4.0 times a bulge radius Rho of the heel-side bulge surface in the horizontal plane. 2. The bulge radius Rti of the toe-side bulge surface in an arbitrary horizontal plane is 1.2 to 4.0 times the bulge radius Rhi of the heel-side bulge surface in the same horizontal plane. The wood type golf club head according to claim 1. 3. The wood type golf club head according to claim 1, wherein a bulge radius Rto of a toe-side bulge surface passing through the sweet spot point is 400 to 1000 mm. 4. A crown-side roll surface having a roll, wherein the face surface is virtually divided into a crown side and a sole side by a second virtual division line passing right and left through the sweet spot point, The roll radius Rco of the crown-side roll surface on a vertical plane passing through the sweet spot point is 1.2 to 4.0 of the roll radius Rso of the sole-side roll surface on the vertical surface.
4. The method according to claim 1, wherein the number is doubled.
A wood-type golf club head as described in the above. 5. A roll radius Rci on an arbitrary vertical surface of the crown-side roll surface is 1.2 to 4.0 times a roll radius Rsi on the same vertical surface of the sole-side roll surface. The wood type golf club head according to claim 4, wherein 6. The wood-type golf club head according to claim 4, wherein a roll radius Rco of the crown-side roll surface passing through the sweet spot point is 400 to 1000 mm.