JP2006061206A - Wood type golf club head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase carry by reducing a back spin amount while increasing a ball hitting angle. <P>SOLUTION: In a wood type golf club head 1 whose loft angle is 15 degrees or more, a plurality of face line grooves 8 are provided on a face surface 2 and the face line grooves 8 are characterised by that the depth d is 0.35-0.45 mm and amplification width W is 0.75-0.85 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wood type golf club head useful for increasing a flight distance by reducing a backspin amount while increasing a ball launch angle.

  A wood type golf club head such as a driver or a fairway wood usually has a loft angle of about 8 to 26 degrees. The loft angle is one factor that determines the launch angle (angle with respect to the horizontal plane) of the ball at the time of hitting. That is, a head having a large loft angle increases the launch angle of the hit ball and easily obtains a high trajectory. Therefore, a wood type golf club head having a loft angle set to 15 degrees or more is designed and developed for the purpose of easily hitting a high ball.

  Further, wood type golf clubs tend to have a higher head speed at the time of hitting than iron type golf clubs due to the shaft length. For this reason, it is necessary to ensure sufficient durability of the face portion. Based on such an idea, in the conventional wood type golf club head having a loft angle of 15 degrees or more, the depth and width of the face line groove provided on the face surface are both small (for example, the depth is 0.25 to 0). .30 mm, the groove width is 0.6 to 0.7 mm, for example, and the groove pitch is large (for example, 4.0 to 6.5 mm).

  Further, the specification of the face line groove as described above acts in the direction of relatively reducing the friction coefficient of the face surface. For this reason, conventionally, it has been considered that the backspin amount of the ball is also reduced.

  The inventors tried various experiments on wood type golf club heads having a loft angle of 15 degrees or more with different specifications of the face line groove. When limited to different ranges, it has been found that the backspin amount can be further reduced while increasing the launch angle of the ball, and the flying distance can be increased by preventing the blow-up. There are the following as prior art related to the face line groove,

JP 2001-178856 A JP 2001-54599 A

  The present invention has been devised in view of the above circumstances. Based on limiting the depth and width of the face line groove to a certain range, the backspin is increased while increasing the launch angle of the ball. An object of the present invention is to provide a wood type golf club head that reduces the amount to increase the flight distance and does not deteriorate the durability.

  The invention according to claim 1 of the present invention is a wood type golf club head having a loft angle of 15 degrees or more, wherein a plurality of face line grooves extending in the toe and heel directions are provided on the face surface, and the face line The groove has a depth of 0.35 to 0.45 mm and a groove width of 0.75 to 0.85 mm.

  The invention according to claim 2 is the wood type golf club head according to claim 1, wherein the face line groove has a groove pitch of 2.5 to 3.5 mm.

  According to a third aspect of the present invention, the face line groove includes a pair of groove walls which incline in a direction of enlarging the groove width from the groove bottom toward the face surface in the cross section thereof, and the face surface of the groove wall 3. The wood type golf club head according to claim 1, wherein an angle with respect to a normal normal is 10 to 30 degrees.

  Since the wood type golf club head of the present invention has a loft angle of 15 degrees or more, the ball launch angle can be increased and a high trajectory can be easily obtained. Further, by limiting the depth and width of the face line groove to a certain range, it is possible to reduce the backspin amount and increase the flight distance while increasing the launch angle. In particular, when the groove pitch of the face line groove is further limited, deterioration of the durability of the face surface can be prevented more reliably. Further, when the angle of the groove wall of the face line groove is limited, the backspin amount of the hit ball can be further reduced and the flight distance can be increased.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a wood type golf club head according to the present embodiment, FIG. 2 is a front view thereof, FIG. 4 is an AA end view thereof, and FIG. 4 is an exploded perspective view of the head. In the figure, a wood type golf club head (hereinafter sometimes simply referred to as “head”) 1 is connected to a face portion 3 that defines a face surface 2 for hitting a ball, and an upper edge 2 a of the face surface 2. The heel from the toe side edge 2c of the face surface 2 between the crown portion 4 forming the upper surface of the head, the sole portion 5 forming the head bottom surface connected to the lower edge 2b of the face surface 2, and the crown portion 4 and the sole portion 5 The side portion 6 extends to the side edge 2d and forms a side surface of the head, and a hosel portion 7 to which a shaft (not shown) is attached.

  In the present specification, the wood type golf club does not mean that the head material is made of a wood material, but has a head shape or a head shape similar to that which has been mainly formed of a wood material. Point to. Specifically, it includes at least a driver (# 1), a plush (# 2), a spoon (# 3), a buffy (# 4), and a creek (# 5), and these are similar but have different numbers and names It also includes a head having the shape described above.

The volume of the head 1 is not particularly limited, but is preferably, for example, 100 cm ³ or more, more preferably 200 cm ³ or more, still more preferably 300 cm ³ or more, and the upper limit is, for example, 500 cm ³ or less, more preferably 480 cm ^3. In the following, 460 cm ³ or less is more desirable. When the volume of the head 1 is less than 100 cm ³ , the natural frequency of the head is considerably larger than the natural frequency of the ball, and the resilience performance of the head is lowered. On the contrary, when the volume of the head 1 exceeds 500 cm ³ , the head weight tends to be large or difficult to hold, which is not preferable. In order to maintain a sufficient head volume, a hollow portion i is provided inside the head 1 as shown in FIG. The hollow part i may be left hollow or may be provided with a weight adjusting material or the like.

  As shown in FIG. 4, the head 1 has a so-called two-piece structure made of a face member 1A having a face surface 2 and a head main body 1B fixed to the face member 1A to form the head 1. Things are shown.

  The head body 1B includes a crown base portion 14 that forms a main portion of the crown portion 4, a sole base portion 15 that forms a main portion of the sole portion 5, and a connection between the crown base portion 14 and the sole base portion 15. The side base portion 16 constituting the main portion of the side portion 6 and the hosel portion 7 are integrally provided. An annular joint edge O1 joined to the face member 1A is formed on the front surface of the head body 1B.

  The face member 1A is integrally provided with the face portion 3 and an extension portion 9 extending from the face portion 3 to the head rear side (back face side). The face member 1 </ b> A of the present embodiment shows a preferable aspect including substantially the entire area of the face portion 3, but may include a main portion of the face portion 3.

  The extension 9 is formed with a horizontal length D of, for example, about 7 to 30 mm from the respective edges (the upper edge 2a, the lower edge 2b, the toe side edge 2c, and the heel side edge 2d) of the face surface 2, for example. Is done. The extension portion 9 of the present embodiment includes a crown portion side extension portion 9 a that forms a part of the crown portion 3, a sole portion side extension portion 9 b that forms a part of the sole portion 4, and a side portion 5 toe. It includes a toe side extension 9c that forms part of the side part and a heel side extension 9d that forms part of the heel side part of the side part 5. As a result, the face member 1A in this example is substantially bowl-shaped. The rear end face of each extension 9 forms a joining edge O2 that is fixed to the joining edge O1 of the head body 1B. Further, each extension portion 9 and the face portion 3 are not integrally joined by welding or the like, but are integrally formed by bending work such as pressing, casting or forging. The hosel side portion of the face member 1A is cut out in a concave shape, and the hosel portion 7 provided in the head body 1B fits there.

  The head body 1B and the face member 1A are formed of various metal materials such as aluminum alloy, titanium, titanium alloy, and stainless steel. Further, a fiber reinforced resin may be employed for a part of the head body 1B. The head main body 1B and the face member 1A may be made of the same material or different materials. In the case of using different materials, it is preferable to select a combination that allows welding.

  In this embodiment, the head body 1B is made of a cast product of Ti-6Al-4V, which is a titanium alloy that can be easily cast by lost wax, and the face member 1A is made of Ti-4. 5Al-3V-2Mo-2Fe is used respectively. The head 1 is formed by welding the joint edge O1 of the head main body 1B and the joint edge O2 of the face member 1A. In this case, at least one of the head body 1B or the face member 1A is appropriately provided with a claw piece 17 or the like that can provide a small gap for filling the weld metal between the facing joint edges O1 and O2 and can temporarily fix both members. Is desirable. The claw piece 17 of this embodiment is provided on the head main body 1B and is inserted into the inner peripheral surface of the face member 1A, whereby both the members 1A and 1B can be temporarily fixed, and workability during welding can be improved.

  Since the hosel portion 7 is integrally formed with the sole base portion 15 in advance, such a head 1 is useful for reducing variations such as a lie angle and improving molding accuracy. Further, the head 1 having a two-piece structure has fewer welded portions than the one having a three-piece structure, and can improve productivity. Further, since it is useful for suppressing variations in various dimensions and angles of the head, a highly accurate head can be provided.

  In the head 1 of this embodiment, as shown in FIG. 3, the welded portion X is not formed on each edge 2 a, 2 b, 2 c, and 2 d of the face surface 2. When the welded portion is included in each edge of the face surface 2, not only the workability at the time of welding is bad, but also a weld bead that cannot be polished remains on the peripheral portion of the face portion 3 and on the hollow portion i side. There is a tendency to reduce the resilience performance of the head 1 due to the increase in rigidity accompanying the increase in thickness. On the other hand, in the head 1 of the present embodiment, the welded portion X between the face member 1A and the head main body 1B moves away from the edge of the face surface 2 toward the rear of the head. Accordingly, it is possible to suppress a decrease in the resilience performance of the head.

  From the above viewpoints, it is particularly preferable that the length D of the extension 9 is 8 mm or more, more preferably 10 mm or more. On the other hand, if the length D of the extension portion 9 is too large, it becomes difficult to form the face member 12 by plastic working such as forging or pressing, which tends to reduce productivity. From this point of view, the length D of the extension 9 is preferably 30 mm or less, particularly preferably 25 mm or less, more preferably 20 mm or less in combination with any one of the lower limit values.

  Also, as shown in FIG. 3, the head 1 of the present embodiment is configured with a loft angle α of 15 degrees or more. In this specification, the loft angle is a real loft angle. That is, as shown in FIG. 2, the shaft axis line SL is arranged in a vertical plane and is grounded at a lie angle β with respect to the horizontal plane HP, and the face angle (also referred to as a hook angle) is adjusted to 0 degree. In the reference state, an angle formed by the plane VP1 parallel to the vertical plane VP and the face surface 2 is defined. The shaft axis line SL is the axis center line when the head 1 has a club shaft, but when the club shaft is not attached, the axis axis line CL of the shaft insertion hole 7a of the hosel part 7 is used as a reference. And

  A wood type golf club head having a loft angle of 15 degrees or more can easily obtain a high trajectory by increasing the ball launch angle with respect to a horizontal plane. This can reduce the run (rolling distance) of the hit ball, so that the controllability of the distance can be improved. The upper limit of the loft angle of the head 1 is not particularly defined, but if it is too large, the hit ball tends to rise too much and the flight distance is remarkably impaired, so it is preferably 25 ° or less, more preferably 20 ° or less.

  A plurality of face line grooves 8 extending in the toe and heel directions are provided on the face surface 2 of the head 1. The face line groove 8 of this embodiment is processed simultaneously with the molding of the face member 1A. For example, when the face member 1A is formed by pressing or forging, the face line groove 8 is recessed in the face surface 2 by a protrusion provided in the mold. The face line groove 8 extends linearly in the toe and heel directions, and is provided at a distance in the crown and sole directions. In the head 1 of the present invention, the depth d of the face line groove 8 is set to 0.35 to 0.45 mm, and the groove width W is set to 0.75 to 0.85 mm.

  FIG. 5 shows a partial cross-sectional view of the face portion 3 including the cross-section of the face line groove 8. The cross section of the face line groove 8 of this embodiment is line symmetric with respect to the groove center line Wc that divides the groove width W into two. In the cross section, the face line groove 8 includes a groove bottom 8a and a pair of groove walls 8b and 8b disposed on both sides of the groove bottom 8a.

  In the present embodiment, the groove bottom 8 a is formed by a plane parallel to the face surface 2. The pair of groove walls 8b and 8b are inclined in a direction of increasing the groove width W from the groove bottom 8a toward the face surface 2. Further, the groove wall 8b of this example is formed with a substantial plane at its main part. It is desirable that a joint portion 8c formed of an arc having a small curvature radius R1 of, for example, 0.01 to 0.1 mm is provided at a connection portion between the groove bottom 8a and the groove wall 8b. Such a joint portion 8 prevents the stress from concentrating on the connecting portion between the groove bottom 8a of the face line groove 8 and the groove wall 8b at the time of hitting as much as possible, and helps to improve the durability of the face portion 3.

  As shown in FIG. 5A, the depth d of the face line groove 8 is measured in a direction perpendicular to the face surface 2 and between the flat face surface 2 excluding the face line groove 8 and the groove bottom 8b. Is the maximum distance. The groove width W of the face line groove 8 is a distance between the groove edges 8e, 8e measured in parallel with the face surface 2 and perpendicular to the longitudinal direction of the groove. The intersection of the groove wall 8b and the face surface 2 is determined by the R & A golf rule that the radius of curvature must be a circular shape of 0.508 mm or less. For this reason, as shown in FIG. 5A, the groove edge 8e is an inclined surface inclined at 30 degrees with respect to the face surface 2 in the circular portion based on the internal rule “30 degree measurement method” of the R & A. It is determined as the position where S contacts for the first time.

  The specifications of such face line grooves 8 are larger in depth d and groove width W than the specifications of face line grooves provided in conventional wood type golf club heads having a loft angle of 15 degrees or more. In other words, the specifications of the plurality of face line grooves 8 provided in the head 1 of the present embodiment act in the direction of increasing the friction coefficient of the face surface 2 as compared with the conventional one.

  Conventionally, on the premise of an iron-type golf club head, particularly an iron-type golf club head having a large loft angle, it has been considered that the backspin amount of the hit ball increases when the friction coefficient of the face surface is increased. However, in the case of a wood-type golf club head with a relatively small loft angle, such a phenomenon is unexpectedly hardly seen. Rather, when the friction coefficient of the face surface 2 increases, the backspin amount of the hit ball may decrease. found.

  FIG. 6 shows a schematic cross-sectional view at the moment when the ball B contacts the face surface 2. Due to the recent computer simulation technology and the like, when the ball is hit, the cover B1 of the ball B resists the force f1 that applies the backspin by the frictional force, and the internal B2 including the core of the ball B is contrary to this. It has been found that an internal frictional force f2 that tries to twist in the direction works. Such a phenomenon is generally called “recoil phenomenon”. Since the internal frictional force f2 hinders backspin, the backspin amount of the ball decreases as the head in which the recoil phenomenon occurs more strongly. It has also been found that the recoil phenomenon is more intense in wood type heads having a face surface 2 having a loft angle of about 15 to 25 degrees and a large friction coefficient.

  Based on the above analysis theory, the inventors conducted an actual hit test in which a ball was hit with a wood type golf club head having a loft angle of 15 to 25 degrees. It was confirmed that the backspin amount of the hit ball decreased when the friction coefficient of the ball was increased. As described above, by increasing the friction coefficient of the face surface 2 for a wood-type head having a loft angle of 15 degrees or more, the backspin amount can be reduced while maintaining a large ball launch angle. Since such a trajectory does not blow up excessively, a large flight distance can be obtained.

  Here, when the depth d of the face line groove 8 is less than 0.35 mm or the groove width W is less than 0.75 mm, the friction coefficient of the face surface 2 cannot be sufficiently increased, and the backspin amount is reduced. The effect is not noticeable. On the contrary, when the depth d of the face line groove 8 is larger than 0.45 mm or when the groove width W is larger than 0.85 mm, the strength of the face portion 2 is likely to be insufficient. This tends to deteriorate the durability of the face portion 3 by causing cracks or the like due to stress concentration at the bottom of the face line groove 8 or the like with repeated hitting. From this point of view, the depth d of the face line groove 8 is more preferably 0.4 mm or more, and the upper limit is preferably 0.5 mm or less. Similarly, the groove width W of the face line groove 8 is Is more preferably 0.78 mm or more, and the upper limit is more preferably 0.82 mm or less.

  Further, as shown in FIG. 5B, the groove pitch P of the face line grooves 8 is 3.5 mm or less, more preferably 3.0 mm or less. The groove pitch P is the shortest distance between the groove edges 8e, 8e on the same side measured in parallel with the face surface 2 in the adjacent face line grooves 8, 8. Conventionally, in a wood type golf club head having a loft angle of 15 degrees or more, the groove pitch P is normally set to 4.0 mm or more. Therefore, in order to sufficiently increase the friction coefficient of the face surface 2 The current situation is not reached. By setting the pitch P of the face line grooves 8 to 3.5 mm or less and arranging the face line grooves 8 densely, the friction coefficient of the face surface 2 can be further increased. This helps to reduce the backspin amount of the hit ball more effectively. On the other hand, when the groove pitch P is too small, the strength of the face portion 3 is insufficient and the durability tends to be deteriorated. From such a viewpoint, the lower limit of the groove pitch P of the face line groove 8 is preferably 2.5 mm or more, more preferably 2.8 mm or more.

  Further, the angle θ of the groove wall 8b of the face line groove 8 is preferably 10 degrees or more, more preferably 15 degrees or more, and further preferably 20 degrees or more. The angle θ is the angle of the groove wall 8b with respect to the normal N perpendicular to the face surface 2 in the transverse section. When the angle is less than 10 degrees, the corner portion sandwiched between the face surface 2 and the groove wall 8b is sharpened, and the ball tends to be easily damaged at the time of hitting. On the other hand, if the angle θ is too large, the sharpness of the corner portion sandwiched between the face surface 2 and the groove wall 8b is impaired, and the effect of increasing the friction coefficient of the face surface 2 tends to be insufficient. For this reason, the angle θ is preferably 30 degrees or less, more preferably 25 degrees or less.

  Further, as shown in FIG. 2, the face line groove 8 is continuously formed in the central area A of the face surface 2 surrounded by a circle having a radius of 15 mm with the sweet spot SS as the center, without being interrupted by the groove pitch P. It is desirable to be provided. Such a central area A has more opportunities for contact with the ball when hit. Therefore, by closely arranging the face line grooves 8 having a large width and depth in the central region A, it is possible to obtain a trajectory with a small backspin amount while effectively increasing the launch angle.

  In the head 1 of the present invention, the friction coefficient of the face surface 2 is increased by limiting the depth d and the groove width W of the face line groove 8. For example, the face surface 2 is subjected to various surface treatments. Needless to say, the methods can be used together. Examples of the surface treatment method may include shot blasting, shot peening, etching, and / or various vapor deposition methods.

  Face line grooves 8 having a large depth d and a large width W are relatively densely arranged on the face surface 2 of the head 1 of the present embodiment. For this reason, if the thickness of the face part 3 is too small, the strength of the face part 3 is insufficient and the durability tends to be lowered. Conversely, if it is too large, the resilience is lowered and the flight distance of the hit ball tends to be impaired. . From such a viewpoint, the thickness of the face portion 3 is not particularly limited, but is preferably 2.0 mm or more, more preferably 2.2 mm or more, and further preferably 2.4 mm or more. The upper limit is preferably It is 3.5 mm or less, more preferably 3.3 mm or less, and still more preferably 3.0 mm or less. Further, as shown in FIG. 3, the face portion 3 of the present embodiment is formed with a substantially constant thickness. For example, the face portion 3 is larger than the thickness of the central portion and is formed at the peripheral portion thereof. An aspect (not shown) including a portion having a small thickness may be used.

  In order to confirm the effect of the present invention, a driver-type wood type golf club head (real loft angle: 20 degrees) having face line grooves of the specifications shown in Table 1 provided on the face surface was made on a trial basis and various tests were conducted. . As shown in FIG. 4, the head was manufactured by TIG welding a face member of Ti-4.5Al-3V-2Mo-2Fe and a head body of Ti-6Al-4V. The test method is as follows.

<Flight test>
Each test head is equipped with the same shaft made by FRP (MP-200 Flex R, manufactured by SRI Sports Co., Ltd.), and a 45-inch wood-type golf club is prototyped, and the club is attached to a swing robot. A golf ball (“Everio HI-BRID” manufactured by SRI Sports Co., Ltd.) was hit at 10 m for each club at 40 m / s, and the launch angle, backspin amount, and flight distance (carry + run) were measured.

<Durability test>
Each of the above clubs was attached to a swing robot and adjusted so that the head speed was 51 m / s, and the golf balls were hit with 3000 balls for each club. For the case where the face part was damaged in the middle, the number of hit balls was examined. Those that were not damaged were evaluated as “OK”. Table 1 shows the test results.

  Consider the results of the test. First, in Comparative Example 1 having no face line groove, the backspin amount is very large at 3800 rpm, but in Comparative Examples 2 and 3 in which the face line groove is provided, the backspin amount is reduced. . However, since the face line grooves 8 of Comparative Examples 2 and 3 have a relatively large groove width or groove depth, the amount of reduction is not sufficient.

  On the other hand, in the head of the example, compared with the backspin amount of the comparative example 1, is reduced to about 55 to 82%, and a remarkable effect can be confirmed. As a result, the flight distance increased by a maximum of 112% (24.4 yards in distance) in comparison with Comparative Example 1. As described above, it was confirmed that the head of the example significantly reduced the backspin amount and had sufficient practical durability compared to the comparative example. Similar results were obtained for heads with real loft angles of 15, 17, 19 and 25 degrees.

It is a perspective view of a head showing an embodiment of the present invention. It is the front view. It is the AA end elevation. It is a disassembled perspective view of a head. (A), (B) is the fragmentary sectional view of the face part which shows the cross section of a face line groove | channel. It is a cross-sectional schematic diagram at the time of contact between a ball and a face surface. (A)-(C) are the front views of the head of an Example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wood type golf club head 1A Face member 1B Head main body 2 Face surface 3 Face part 4 Crown part 5 Sole part 6 Side part 7 Hosel part 8 Face line groove

Claims (3)

A wood type golf club head having a loft angle of 15 degrees or more,
A plurality of face line grooves extending in the toe and heel directions are provided on the face surface,
The wood type golf club head according to claim 1, wherein the face line groove has a depth of 0.35 to 0.45 mm and a groove width of 0.75 to 0.85 mm.   2. The wood type golf club head according to claim 1, wherein the face line groove has a groove pitch of 2.5 to 3.5 mm.   The face line groove includes a pair of groove walls inclined in a direction in which the groove width is increased from the groove bottom toward the face surface in a cross section thereof, and an angle with respect to a normal line perpendicular to the face surface of the groove wall is 10 to 10. The wood type golf club head according to claim 1 or 2, wherein the angle is 30 degrees.

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