JP2004188190A - Wood type golf club head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wood type golf club head which can stabilize directivity of a hit ball. <P>SOLUTION: In this wood type golf club head, a gravity center distance (d) which is the shortest distance between the axial center line of a shaft and the center of gravity G of the head is made 45-50 mm in a condition that the axial center line of the shaft is placed in a vertical plane and tilted in a prescribed lie angle and placed on the horizontal plane by making a face angle O°. On the area gravity center FC on a face plane and a sweet spot point SS where the perpendicular line directed from the area gravity center FC to the face plane crosses the face plane, a horizontal tangential line in contact with the face plane passing the area gravity center FC, a point T where the horizontal tangential line in contact with the face plane passing the area gravity center FC crosses the perpendicular line from the sweet spot point SS to the tangential line is positioned in a face plane center area within 2 mm length on the tangential line to the toe side and 4 mm to the heel side by making the area gravity center FC as the reference. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a wood type golf club head capable of improving the directionality of a hit ball.

When a golfer who is relatively inexperienced at a beginner or intermediate level hits a ball with a wood-type golf club such as a driver, the ball is likely to be sliced spin (in the case of a right-handed golfer, the hitting ball tends to move rightward). ). As this cause,
(1) The ball is hit with the face surface open (FIG. 10A),
(2) The swing trajectory of the head is a so-called outside-in trajectory, and the ball is cut (FIG. 10B).
(3) Gear effect by hitting on the heel side of the face surface (FIG. 10C),
Etc. are considered.

  Conventionally, as a measure to prevent slice spin of the hit ball, the head center of gravity distance (the shortest distance from the head center of gravity to the shaft axis line of the shaft) is set small to improve the “head return” and the face surface opens when hitting Attempts to prevent this are known. That is, conventionally, in order to improve the return of the head, it has been considered effective to reduce the moment of inertia of the head around the axial center line of the shaft. Related prior art documents include the following.

JP 2001-231897 A Japanese Patent Laid-Open No. 9-271545 JP-A-6-343721 JP-A-9-192269 Japanese Patent Laid-Open No. 11-267251

  The inventors have conducted a number of actual hit tests on golfers with low skill levels as described above, and examined changes in swing patterns and face angles during swings. In many cases, the face surface was open, and it turned out that the result was completely opposite to the above prediction. As a result of further experiments, it was found that slice spin can be reduced by appropriately limiting the center-of-gravity distance of the head and the position of the sweet spot point.

  As described above, an object of the present invention is to provide a wood type golf club head that can reduce slice spin and improve the directionality of a hit ball.

According to the first aspect of the present invention, the shaft center line is arranged in a vertical plane, tilted at a specified lie angle, and placed in a horizontal plane with a face angle of 0 °. The center-of-gravity distance d, which is the shortest distance between the shaft center line and the head center of gravity G, is 45 to 50 (mm), and the area center of gravity FC of the face surface and the perpendicular line from the head center of gravity G to the face surface are In the sweet spot point SS that intersects the face surface,
A point T where a horizontal tangent line that passes through the area centroid FC and touches the face surface and a perpendicular to the tangent line from the sweet spot point SS intersects with the area centroid FC as a reference, the length on the tangent line is on the toe side The wood-type golf club head is positioned in the center area of the face surface within 2 (mm) and within 4 (mm) on the heel side.

  Here, the “face surface” is defined as a portion surrounded by the peripheral edge when the peripheral edge can be visually identified such as a clear ridge line. However, when the peripheral edge of the face surface is not clear, as shown in FIG. 8A, the head is cut along a number of planes E1, E2,... Including the straight line connecting the center of gravity G of the head and the sweet spot point SS. As shown in FIG. 8B, a position Pe where the curvature radius r of the face outer surface outline Lf is 200 mm or less for the first time when viewed from the center side of the face surface is defined as the peripheral edge. An area surrounded by the position Pe is defined as a face surface. The face outer surface outline Lf is determined by filling a face line, a punch mark, or the like.

The invention according to claim 2 is the wood type golf club head according to claim 1, wherein the center-of-gravity distance d is 47 to 48 (mm) and the head volume is 300 (cm ³ ) or more.

  In the invention according to claim 1, in addition to improving the return of the head by appropriately limiting the center of gravity distance and the position of the sweet spot point with respect to the area center of gravity on the face surface, the hit point and the sweet spot point are matched, The direction of the hit ball can be improved by reducing the slice spin. Further, since the return of the head is improved and the grip of the ball is improved, even an average golfer can easily hit a so-called draw-type ball muscle, leading to an improvement in the flight distance.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 illustrates a driver (# 1) as a wood-type golf club head (hereinafter sometimes simply referred to as “head”) 1 of the present invention. The wood type golf club includes a head that is conventionally made of a wood material, and the head material is not made of a wood material, and includes at least a driver (# 1), a plush (# 2), a spoon ( The concept includes # 3), buffy (# 4), and clique (# 5).

  The head 1 includes a face portion 3 having a face surface 2 which is a surface for hitting a ball, a crown portion 4 which is connected to the peripheral edge 2a on the face surface 2 and forms the upper surface of the head, and a peripheral edge 2b below the face surface 2. The face surface 2 passes through the back face from the toe-side peripheral edge 2t of the face surface 2 by connecting between the sole portion 5 (not visible in FIG. 1) that forms a bottom surface of the head and the crown portion 4 and the sole portion 5. A neck portion 7 which is provided in the vicinity of the heel side intersection where the face portion 3, the crown portion 4 and the side portion 6 intersect with each other, and which is attached to one end of a shaft (not shown). Are provided.

  The neck portion 7 is formed with a cylindrical shaft insertion hole 7a. The shaft is inserted concentrically into the shaft insertion hole 7a with the axial center line aligned. Accordingly, the shaft center line CL of the shaft insertion hole 7a and the shaft axis center line (SL) substantially coincide with each other. Therefore, in this specification, when the head 1 is adjusted to the lie angle, the axis of the shaft insertion hole 7a The center line CL is used as a reference.

  The head 1 may be made of, for example, aluminum alloy, titanium, titanium alloy, stainless steel, or other various metal materials, but may be partially or entirely made of fiber reinforced resin. Although not particularly limited, it is preferably formed of a titanium alloy having a high specific strength. Further, the head 1 of this example is formed by the lost wax precision casting of Ti-6Al-4V, which is an α + β type titanium alloy, and joining the remaining parts thereto by welding or the like. Indicates. However, the manufacturing method is not limited to such an embodiment, and can be manufactured by other materials and other molding methods.

  2 to 4 show a front view, a side view, and a plan view of the head 1 in a measurement state. The measurement state of the head 1 uniquely defines the posture of the head 1 with respect to the horizontal plane HP. Specifically, the shaft center line SL of the shaft is arranged in an arbitrary vertical plane VP1 and has a specified lie angle. It is in a state where it is tilted by β (the lie angle determined for the head) and grounded to the horizontal plane HP with a face angle of 0 °. When the face angle is set to 0 °, as shown in FIG. 4, the head is moved around the axis center line CL so that a horizontal tangent line L in contact with the area gravity center FC of the face surface 2 is parallel to the vertical surface VP1. Rotate to adjust. FIG. 5 is a head end view of the vertical plane VP1 in FIG.

  In the measurement state, the head 1 of the present invention sets the center-of-gravity distance d, which is the shortest distance between the shaft centerline SL of the shaft and the head center-of-gravity G, to 45 to 50 mm.

  In the experiments conducted by the inventors, a number of actual hit tests were conducted on golfers of beginner to intermediate level (approximately 15 or more levels in terms of handicap). FIG. 6 shows, as a representative example, a change in the face angle during a swing when a golf player (testers 1 to 5) performs a hit test using two types of clubs. In FIG. 6, the horizontal axis indicates the face angle at a position 10 cm before the impact, and the vertical axis indicates the face angle immediately before the impact. Further, the face angle is displayed as 0 ° when the face surface is directly facing the target flying ball direction,-when the face is open more than this, and + when it is closed.

  As shown in FIG. 6, in the heads using the comparative head with the center-of-gravity distance d of 28.1 mm, the face angle immediately before the impact is wide.

  On the other hand, in the club using the head of the example in which the center-of-gravity distance d is set to 47.5 mm, which is larger than the conventional one, the face angle immediately before the impact is very small in all the testers 1 to 5. . Further, in detail, in the tester 1, the change in the face angle from 10 cm before the impact to just before the impact is very small. In later impressions, the tester 1 feels that the head with the larger center-of-gravity distance d has already returned at the top position of the swing. And it looks like it is in a state of 10cm before impact-just before impact. This is because, as shown in FIG. 11, the swing pattern of the tester 1 is a type in which the top position is relatively low and the face surface is returned from an early stage. Since the moment foot is large, the weight of the head promotes the return of the face, and it is considered that the return of the face is promoted, such as a large moment that closes the face.

  On the other hand, the testers 2 to 5 obtained completely different results from the tester 1 when the head of the example was used. That is, the face angle from 10 cm before impact to just before the impact changes very greatly in the closing direction. A head with a large center-of-gravity distance d has a large moment of inertia around the shaft axis, so it is difficult to rotate the head around the axis centerline of the shaft at the initial stage. There is little decrease in speed. This is considered to be a cause of effectively closing the face immediately before impact.

  As a result of examining a large number of beginner to intermediate golfers, it has been found that golfers having such a skill level have very many two swing patterns as described above. Based on such knowledge, the present invention can suppress the opening of the face and reduce the slice spin by setting the center-of-gravity distance d of the head 1 to be larger than the conventional one. If the center of gravity distance d is less than 45 mm, the face is likely to open at the time of impact as in the comparative head, but conversely, if the center of gravity distance d exceeds 50 mm, the shaft is centered around the axis of the shaft. Since the moment of inertia becomes excessively large, it is easy to have an impact with the face still open. Particularly preferably, the center-of-gravity distance d is 47 to 49 mm, more preferably 47 to 48 mm.

Such a head 1 having a large center-of-gravity distance d can be realized by reviewing the head weight distribution design. For example,
(A) increasing the head volume;
(B) Increase the length of the head toe and heel direction.
(C) The toe side thickness of the head is larger than the heel side thickness,
(D) adding a heavy object to the toe side of the head;
One or more means such as can be combined.

It is known that when the head volume is increased, the moment of inertia of the head is increased, and even if the impact position is slightly deviated, the head blur is small and helps to stabilize the directionality of the hit ball. From such a viewpoint, the head volume is desirably 300 cm ³ or more, more preferably 350 cm ³ or more, and particularly preferably 400 cm ³ or more. On the other hand, the upper limit of the head volume is not particularly limited because it is sufficient if it is within a range that is practically acceptable for a golf club. However to prevent such head weight excessive increase or decrease in the durability, the head volume, for example 600 cm ³ or less in combination with any of the above lower limit value, further 550 cm ³ or less, or 500 cm ³ or less, or 450 cm ³ Hereinafter, it may be set to 425 cm ³ or less. The head volume is a volume including the neck portion 7.

Further, when the head volume is increased, the inertial moment Ia around the axis perpendicular to the horizontal plane HP passing through the head center of gravity G and the center of the head around the axis parallel to the horizontal plane HP and the vertical plane VP1 in the head measurement state. The moment of inertia Ib increases. On the other hand, the head weight is subject to certain restrictions due to the balance with the swing balance. Therefore, for example, when the head volume is 300 cm ³ or more and less than 350 cm ^{3, the} inertia moment Ia is 2800 g · cm ² or more and the inertia moment Ib is 1700 g · cm ² or more, and when the head volume is 350 cm ³ or more and less than 400 cm ^3, moment of inertia Ia is 3400 g · cm ² or more and moment of inertia Ib is 2000 g · cm ² or more, further wherein the moment of inertia Ia when the head volume is 400 cm ³ or more is 3800 g · cm ² or more and moment of inertia Ib is 2700 g · cm ² or more Is set.

  The face bulge and the face roll are desirably set in association with the head volume (in other words, the moments of inertia Ia and Ib). The face bulge is a radius of curvature of the face surface 2 cut by a horizontal plane passing through the area center of gravity FC of the face surface 2 in the measurement state of the head, and the face roll passes through the area center of gravity FC of the face surface 2 and the shaft. The radius of curvature of the face surface 2 is cut by a vertical plane perpendicular to the vertical plane VP where the axis center line SL is located.

  When the head volume is increased, the inertia moments Ia and Ib are also increased as described above, and the head shake is reduced even at the time of a miss hit. Thereby, the influence of the spin amount of the ball due to the gear effect is reduced. On the other hand, the face bulge and face roll control the ball jumping angle immediately after launch according to the spin generated by the gear effect. For example, as shown in FIG. 7, when a face bulge having a radius of curvature R is provided on the face surface 2, when a ball is hit on the toe side, the ball is launched to the right of the target flying ball direction F1. However, since the hook spin due to the gear effect acts on the ball, the hit ball bends in the direction of the target flying line as indicated by the arrow F3, and deviation from the target flying edge is reduced.

In this way, the face bulge aims to stabilize the directionality of the hit ball by synergistic action with the gear effect by controlling the right and left jump angles of the ball immediately after launch. The same applies to the face round because the above effect appears in the vertical direction. Therefore, it is preferable that the face bulge and the face roll (hereinafter, collectively referred to as “face round”) be defined in relation to the influence of the gear effect, in other words, the head volume. Specifically, when the head volume is 300 cm ³ or more and less than 350 cm ^{3, the} radius of curvature of the face round is preferably 229 to 330 mm, more preferably 254 to 305 mm. When the head volume is 350 cm ³ or more and less than 400 cm ³ , the radius of curvature of the face round is preferably 254 to 356 mm, more preferably 267 to 330 mm. Further, when the head volume is 400 cm ³ or more, the radius of curvature of the face round is preferably 279 to 381 mm, more preferably 292 to 356 mm.

  The radius of curvature of the face round of the face surface 2 is set in the above range, but the area of the face surface located in the vicinity of the periphery of the face surface 2 is a radius of curvature that deviates from the range of the curvature range. Also good. The face surface 2 set in this way is connected to other regions (crown portion 4, sole portion 5 and side portion 6) of the head. The boundary between the face surface 2 and the other regions is the face surface 2. Is the periphery. The peripheral edge of the face surface may be an edge shape such as a ridge line, but from the viewpoint of head durability, it is formed with a radius of curvature smaller than the radius of curvature of the face round and smoothes the face surface 2 and other regions. It is preferable to provide the peripheral edge of the face surface in the change region that is the connecting portion. As described above, in the former case, the edge portion is the periphery of the face surface 2, and in the latter case, the radius of curvature gradually decreases from the center direction of the face surface toward other regions in the changed portion. The position where the radius of curvature is 200 mm or less for the first time is the periphery of the face surface.

  By the way, when the center-of-gravity distance d is set to be large as in the head 1 of the present invention, the head center-of-gravity G tends to be closer to the toe side of the face surface 2, and as a result, the perpendicular Q from the head center-of-gravity G to the face surface 2 is The sweet spot point SS that intersects the surface 2 is located closer to the toe side. However, since the golfer usually cannot know where the sweet spot point SS is located on the face surface 2, the golfer tries to hit the ball at the center of the face surface 2. For this reason, simply increasing the center-of-gravity distance d makes it easier to hit the ball on the heel side than the sweet spot point SS, which may cause slice spin due to the above-described factor (3).

  Therefore, in the present invention, while the center-of-gravity distance d is set to be large, the area center of gravity FC and the sweet spot point SS of the face surface 2 pass through the area center of gravity FC and touch the face surface 2 as shown in FIGS. The point T where the horizontal tangent L and the perpendicular line J to the tangent L from the sweet spot point SS intersect, with the area centroid FC as a reference, the length x on the tangent L is within 2 mm on the toe side and on the heel side It is located in the face surface central area Ac within 4 mm. Thereby, the hit point targeted by the golfer and the sweet spot point SS can be substantially matched, and the occurrence of slice spin can be suppressed by removing the above-described factor (3).

  Further, when the point T has a length x on the tangent L that exceeds 2 mm on the toe side with respect to the area center of gravity FC, if the ball is hit with the area center of gravity FC of the face surface 2, the heel is larger than the sweet spot point SS. It will hit at a position off the side. Therefore, as in the above factor (3), slice spin is easily applied due to the gear effect, and the directionality is impaired. On the other hand, when the length of the point T on the tangent line L exceeds 4 mm on the heel side with respect to the area center of gravity FC, if the ball is hit with the area center of gravity FC of the face surface 2, the point T is larger than the sweet spot point SS. It will hit at a position off the side. This is likely to cause hook spin due to the gear effect, and similarly impairs directionality. In addition, since the center-of-gravity distance d is set to be large, for example, the face surface must be provided too close to the head, and the head shape tends to give a feeling of strangeness.

  An object of the present invention is to reduce slice spin. For this reason, it is important to reduce the probability of hitting the ball on the heel side from the sweet spot point SS. Therefore, as described above, the allowable amount on the toe side of the length x on the tangent line L is 2 mm, while the heel side is 4 mm, which is twice that, allowing the head center of gravity G to be closer to the heel. . More preferably, the range of x is 1 mm on the toe side, 2 mm on the heel side, particularly preferably 0 mm on the toe side and 1.5 mm on the heel side.

  Needless to say, the head 1 of the present invention can be applied to a fairway wood or the like in addition to the driver. The loft angle is preferably about 7 to 12 °, more preferably an average golfer for a head of 10.5 to 12 °, particularly about 11 to 12 °.

  A wood-type golf club head having the basic form shown in FIGS. 1 to 5 was made on the basis of the specifications shown in Table 1, and the same carbon shaft (MP-100 Flex R, manufactured by Sumitomo Rubber Industries) was attached to the golf club head. An inch, balance D0 wood type golf club was manufactured, and a test hit test and an impression test were conducted. Each head was formed by welding a face plate made of Ti-4.5Al-3V-2Mo-2Fe to a head body cast from Ti-6Al-4V. The loft angle was 11 °, the face angle was 2 °, the lie angle was 56 °, and the head mass was 188 g. Both face bulge and face roll are standardized to 254mm.

The center of gravity of the head was adjusted by changing the thickness on the toe side and heel side of the head. The lower limit of the wall thickness was 0.8 mm, and the upper limit was as much as possible within the limits of the head volume and mass. Specifically, except for Example 2 (head volume 470 cm ³ ), the upper limit was 2.2 mm, and in Example 2 the upper limit was 1.6 mm.

The test hit test consists of 100 right-handed golfers with handicap of 15 or more hitting 10 golf balls (“MAXFLI HI-BRID” manufactured by Sumitomo Rubber Industries, Ltd.) using each test club. It went by. Then, in order to examine the return of the head at the time of impact, the amount of right / left deviation of the hit point of the hit ball with respect to the target direction was measured. For each golfer, an average of 10 balls was calculated for each golfer, and the results for these 10 players were further averaged. In addition, when the hit ball is shifted in the left direction, a negative display is made. The inertia moment of the head was measured using a device called MOMENT OF INERTIA MEASURING INSTRUMENT manufactured by INERTIA DYNAMICS Inc. Also, the impression test was conducted by examining whether or not the head shape felt uncomfortable when it was normally held, and evaluated by the number of golfers who felt uncomfortable.
Tables 1 and 2 show the test results.

  In Example 1, even the golfer with the best balance and easy slicing had the falling point deviated to the left, and a very good result was obtained. In Example 2, the distance x is the same as in Example 1, but it can be seen that the variation is further reduced because the head volume is large. In Examples 1 and 2, the absolute value of the absolute value of the deviation amount of the total number of hit balls is 12.8 m and 5.2 m, respectively.

  In Example 3, since the distance x is negative (the sweet spot is on the toe side relative to the area center of gravity), a slice spin due to the gear effect is likely to be applied, though slightly. For this reason, although the falling point is on the right side, the deviation amount itself is small and sufficiently satisfactory as compared with the comparative example. Further, in Example 4, since the distance x is positive (the sweet spot is on the heel side with respect to the area center of gravity), hook spin tends to be slightly applied due to the gear effect. For this reason, the drop point is on the left side, but the result is satisfactory. In the fifth embodiment, the distance x is substantially the same as that of the fourth embodiment, but the center-of-gravity distance d is set to be slightly larger. In Example 6, the sweet spot is close to the toe, and the slice spin is likely to be applied. However, the center of gravity distance d is large and the head is easy to return, so that the shift amount is small.

  On the other hand, since the center-of-gravity distance d is too large in the comparative example 1, and the center-of-gravity distance d is conversely too small in the comparative example 2, the amount of deviation in the right direction is large. In Comparative Example 3, the center-of-gravity distance d is appropriately regulated, but the distance x is too small (the sweet spot is positioned too far on the toe side with respect to the area center of gravity of the face surface). The amount of displacement to the right is large due to the effect of the pin. In Comparative Example 4, since the distance x is too large (the sweet spot is located on the heel side with respect to the center of gravity of the area of the face surface), the shift amount to the left is increased due to the hook spin due to the gear effect. . FIG. 9 shows the relationship between the distance x and the center-of-gravity distance d including the conventional head and the head of the comparative example.

It is a perspective view which shows the head of this embodiment. It is a front view which shows the measurement state of a head. It is a side view which shows the measurement state of a head. It is a top view which shows the measurement state of a head. FIG. 5 is an end view of a cutting plane parallel to the vertical plane VP1 of FIG. It is a graph which shows the change of the face angle during a swing. It is a top view explaining the relationship between a gear effect and a face bulge. (A) is a front view illustrating the face surface, and (B) is a sectional view thereof. It is a graph which shows distribution of the gravity center distance d of a head. (A), (B), (C) are schematic plan views for explaining the cause of slice spin. 3 is a schematic diagram illustrating a swing pattern of the tester 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wood type golf club head 2 Face surface 3 Face part 4 Crown part 5 Sole part 6 Side part 7 Neck part d Center of gravity distance x Distance SL Shaft axis center line

Claims (2)

In the measurement state where the shaft center line is placed in the vertical plane and tilted at the specified lie angle and the face angle is set to 0 °,
The center-of-gravity distance d, which is the shortest distance between the shaft center line of the shaft and the head center-of-gravity G, is set to 45 to 50 (mm),
In addition, the area gravity center FC of the face surface and the sweet spot point SS where the perpendicular line from the head gravity center G to the face surface intersects the face surface,
A point T where a horizontal tangent line that passes through the area centroid FC and touches the face surface and a perpendicular to the tangent line from the sweet spot point SS intersects with the area centroid FC as a reference, the length on the tangent line is on the toe side A wood-type golf club head characterized by being positioned in the center area of the face surface within 2 (mm) and within 4 (mm) on the heel side. The centroid distance d 47-48 (mm) a is and wood type golf club head according to claim 1, wherein the head volume 300 (cm ³⁾ or more.

Images