CN113018805A - Golf club head and golf club - Google Patents

Abstract

The invention provides a golf club head, which does not reduce the durability near the position where the golf ball is actually hit, effectively improves the flexibility, and does not affect the hitting performance. A golf club head of the present invention has a front face portion (5) having a striking face formed with a scribed line, and a thin portion is formed on the back face of the front face portion (5). On a perpendicular line passing through a geometrically central position (FC) of the front face portion, when a hitting position defined by a position 15mm in height from a head front edge (LE) is defined as (C), the thin-walled portion is formed so as not to include an effective hitting region (R1) defined within 10mm of a radius centering on the hitting position (C). The thin portion has a toe side recessed portion (21) provided on the toe side and a heel side recessed portion (22) provided on the heel side with respect to an effective striking area (R1), and the toe side recessed portion (21) and the heel side recessed portion (22) are formed in a region below the heel side upper end position of the striking surface of the front portion.

Description

Golf club head and golf club

Technical Field

The present invention relates to a golf club, and more particularly, to a golf club head suitable for a metal type golf club.

Background

In general, it is known that a front surface portion of a head of a metal type golf club, on which a ball is struck, is integrally formed with a head body, or a front member separate from the head body is integrally formed with the head body by bonding, welding, caulking, or the like. In such a head, it is known that a groove is formed in the rear surface of the front surface portion in order to facilitate the deflection of the front surface portion (hereinafter, including a front member that is separate from the head main body) and to increase the flight distance. That is, since the groove is formed, the rigidity of the groove portion is reduced, and therefore the flexibility of the front portion can be improved.

For example, patent document 1 discloses a structure in which long grooves are formed in the toe-heel direction on the top side and the bottom side of the back surface of the front surface portion. In general, in a flat front portion having no groove, the geometrically central position (also referred to as front center FC) is the most flexible region, and the geometrically central position can be made more flexible by forming the long grooves on the top and bottom sides as described above. That is, since the amount of deflection of the geometrically central region of the front portion increases, the rebound force at the time of hitting a ball increases, and the flight distance increases.

However, in most of metal type golf clubs, a ball is hit from the ground without raising the mat, and the actual hitting position is located below the geometrically central position. Specifically, the height of the geometrically central position is about 20mm from the ground contact surface of the head (head front edge), while the height of the actual hitting position is about 15mm from the ground contact surface of the head. That is, in order to increase the rebound resilience (to largely deflect the front surface portion), it is preferable that the distance be about 15mm from the ground contact surface of the head. In view of this point, for example, patent document 2 discloses a configuration in which a plurality of grooves parallel to the scribe lines are formed in the lower region on the back surface of the front surface portion, thereby reducing the rigidity of the lower region. The grooves formed on the rear surface of the front surface portion are provided corresponding to regions between the scribed lines (band-shaped regions), and the grooves are connected by connecting grooves extending in a direction intersecting the extending direction of the grooves.

Patent document

Patent document 1: japanese patent No. 5537382 publication

Patent document 2: japanese patent No. 6347305 publication

Disclosure of Invention

As described above, by forming the groove in the back surface of the front surface portion, the flexibility can be improved without increasing the weight of the front surface portion, and as disclosed in patent document 2, forming the groove in the lower region of the front surface portion to reduce the rigidity is effective for increasing the amount of the flexibility in the lower region.

However, if the groove is formed in the actual hitting region, the strength is directly lowered, and therefore, the wall thickness of the front portion cannot be reduced, and the effect of improving the flexibility is not high. Further, if grooves are formed in the portion where the ball hits, the ball deforms at the moment of hitting, and the feeling of hitting soft like sticking to the front is reduced (the feeling of hitting is reduced).

The present invention has been made in view of the above problems, and an object of the present invention is to provide a golf club head and a golf club which can effectively improve flexibility without lowering durability in the vicinity of a position where a ball is actually hit, and which does not affect hitting performance.

In order to achieve the above object, the present invention provides a golf club head including a face portion having a striking surface on which a reticle is formed, and a thin portion formed on a rear surface of the face portion, wherein the thin portion is formed so as not to include an effective striking area defined within a radius of 10mm with respect to a striking position C defined as a center on a perpendicular line passing through a geometrically central position of the face portion and defining the striking position as a position 15mm from a head front edge, the thin portion includes a toe-side concave portion provided on a toe side with respect to the effective striking area and a heel-side concave portion provided on a heel side, and the toe-side concave portion and the heel-side concave portion are formed in a region below a heel-side upper end position of the striking surface of the face portion.

Since the front surface portion of the above-described structure is formed with the toe-side concave portion and the heel-side concave portion on the back surface thereof so as not to include the sweet spot region defined within a radius of 10mm with the hitting position C as the center, the flexibility (rebound resilience) of the sweet spot region can be effectively improved, and the flight distance of a hit ball can be improved. In particular, since the toe-side concave portion and the heel-side concave portion are formed in the lower region than the heel-side upper end position of the face portion, the flexibility within a radius of 10mm around the hitting position C can be improved, the tolerance of the off-center hit (miss hit) can be improved, and the flight distance is not greatly reduced. Further, since no recess is formed in the effective striking region where a ball strike actually occurs, the rebound performance can be effectively improved without reducing the fatigue strength and the feeling of striking the ball at the striking portion.

In the above-described configuration, the hitting surface indicates an area in which a scribed line is formed on the surface of the front surface portion, and the effective hitting area indicates an area within a certain range in consideration of a deviation in a normal hitting operation by a golfer within the hitting surface. That is, although the golfer swings through the hitting position C, the deviation occurs from the hitting position C, and the flexibility of the region where the deviation occurs is intended to be improved in the present invention. In the present invention, the effective hitting area is set to a range within 10mm of the radius around the actual correct hitting position (hitting position defined by a position 15mm in height from the front edge of the head) C, and it is desired to improve the rebound resilience within this range.

Further, since the thin portion (concave portion) having low rigidity for improving the rebound resilience is not formed at least in the effective hitting region, the fatigue strength and the feeling of hitting at the hitting portion are not reduced. The toe-side concave portion and the heel-side concave portion may be configured by a groove, a concave portion in a certain range, or a combination of these portions, and may be appropriately deformed in terms of shape, depth, and the like, as long as the center region of the front portion on the lower side than the geometric center position (front center) of the front portion is made less rigid.

The head having the above-described front structure can be applied to a metal golf club without being affected by the size of the club.

According to the present invention, a golf club head and a golf club can be obtained which are effective in improving flexibility without lowering durability in the vicinity of a position where a ball is actually hit, and which do not affect hitting performance.

Drawings

Fig. 1 is a view showing a golf club head according to embodiment 1 of the present invention, and is a front view of the head.

Fig. 2(a) is a sectional view taken along the line ii (a) -ii (a) of the head shown in fig. 1, and (b) is a sectional view taken along the line ii (b) -ii (b) of the head shown in fig. 1.

Fig. 3 is a rear view of the head according to embodiment 1.

Fig. 4 is a view showing embodiment 2 of the present invention, and is a view of the head as viewed from the rear side.

Fig. 5(a) to (c) are views showing embodiments 3 to 5 of the present invention, respectively, and are rear views of front faces.

Fig. 6(a) to (c) are views showing embodiments 6 to 8 of the present invention, respectively, and are rear views of front faces.

Fig. 7(a) to (c) are views showing embodiments 9 to 11 of the present invention, respectively, and are rear views of front faces.

Fig. 8(a) and (b) are views showing the 12 th and 13 th embodiments of the present invention, respectively, and are rear views of a front face.

Description of the symbols

1-a club head; 1A-a club head body; 5-face part; 7-scribing; 21. 31, 41, 51, 61, 71-toe side concavity; 22. 32, 42, 52, 62, 72-heel-side concavity; FC-geometrically central location; c-ball impact position; r-a ball striking face; r1-sweet spot.

Detailed Description

Hereinafter, an embodiment of a metal type golf club head (hereinafter, referred to as a head) according to the present invention will be specifically described with reference to the drawings.

Fig. 1 to 3 are views showing a 1 st embodiment of the present invention, fig. 1 is a front view of a head, fig. 2(a) is a sectional view taken along the line ii (a) -ii (a) of the head shown in fig. 1, fig. 2(b) is a sectional view taken along the line ii (b) -ii (b) of the head shown in fig. 1, and fig. 3 is a view of the head viewed from the rear side.

The golf club to which the head according to the present embodiment is attached is a metal type club, and a front end of a shaft (not shown) to which a grip is attached on a base end side is fitted into and fixed to a hosel 1B, and the hosel 1B is integrally formed with a head main body 1A constituting the head 1. The shaft and the head body 1A are set so that a predetermined lie angle α is formed between the axis X of the fixed shaft and the reference horizontal plane P when the golf club is set at the hitting position with respect to the reference horizontal plane P. In this case, the shaft may be made of steel or may be made of fiber-reinforced resin (FRP).

The head body 1A is integrally formed with a front face portion 5 for generating a hitting ball. The front surface portion 5 is formed in a plate shape, and includes a front surface 5a on which a shot occurs on the front side, a rear surface 5b on which a thin portion (recess) described later is formed on the rear side, and the front surface 5a of the front surface portion 5 is formed to have a predetermined loft angle β corresponding to the club number.

The head main body 1A integrally formed with the front surface portion 5 can be integrally formed by casting or the like using a metal material such as titanium, a titanium alloy, stainless steel, carbon steel, or tungsten, and has a structure including an upper portion 1A, a sole portion 1b, a toe portion 1c, and a heel portion 1d around the front surface portion 5. In this case, the front face portion 5 may be formed of a plate-like member other than the head body (for example, integrally formed by casting or the like using a metal material such as titanium, a titanium alloy, stainless steel, carbon steel, or tungsten), or may be formed in a ring shape, for example, so that the head body 1A is fixed to the opening portion by caulking, welding, bonding, or the like, thereby forming a separate front face member. The end of the front face portion 5 may constitute a part of the upper portion, the sole portion, and the like of the head body.

As described above, the head body 1A includes the upper portion 1A, the sole portion 1b, the toe portion 1c, and the heel portion 1d, and these portions extend rearward along the peripheral edge of the front portion 5. In the present embodiment, the upper portion 1a extends rearward, the tip end side thereof is bent so as to hang downward, and the bottom portion 1b extends rearward, and a rear member 1f that extends rearward and stands upward is integrated at the tip end position thereof by welding or the like. The tip end of the rear member 1f is erected to a position substantially midway between the toe portion 1c and the heel portion 1d, and is formed of a material having a higher specific gravity than the material constituting the head body 1A, so that the center of gravity of the head body can be effectively lowered. The rear member 1f may be formed integrally with the head body, or may be formed by attaching another weight member thereto.

Similarly, the toe portion 1c and the heel portion 1d extend rearward and are curved toward the center at the tip end side, so that the head body 1A has a cavity structure in which the rear side of the front portion 5 is open, and the flexibility of the front portion as a whole is improved.

The head body 1A has a shape that increases in height as it moves from the heel side to the toe side, and a plurality of scribe lines 7 are formed in parallel in the toe-heel direction on the front face 5a of the front face portion 5 having the same shape. In the present invention, the region R where the score line 7 is formed is defined as the face of the front face portion 5. For example, the striking surface R is formed by performing a masking process on the outer side of each of the toe side edge Ra and the heel side edge Rb and performing a surface roughening process such as sandblasting.

A geometrically central position (front center) FC exists within the striking face R of the face portion 5. When the player hits the ball, although the ball hit occurs in the vicinity of the perpendicular line passing through the geometric center position FC in the toe-heel direction (the player hits the ball with awareness of this point), as described above, the actual hit position in the height direction is located below the geometric center position FC. Specifically, the height H is a position at which the sole portion 1b of the head body moves along the ground surface and a ball hit occurs in a state in which the ball is set on the ground surface, and is about 15mm from the head front edge LE of the sole portion 1 b. In a metal type golf club, the position is a position (ideal hitting position) at which a shot is made in a state where a so-called shaving or thick shot does not occur, and this position is defined as a hitting position C. Although the hitting position C varies depending on the type of club, the score line 7 is approximately near the 4 th position from the lowermost end, and a golfer usually tries to hit a ball near the hitting position when swinging.

Further, although the geometric center position FC and the hitting position C are shown on the back surface of the front surface portion shown in fig. 3, these positions match the geometric center position FC and the hitting position C shown on the hitting surface side of the front surface portion shown in fig. 1.

Since the rear side of the front face portion 5 has a cavity structure as described above, the front face portion as a whole can flex, and the most flexible position is near the geometrically central position FC. In fact, since the front portion 5 has a shape in which the length on the heel side is short and the length increases as it moves to the toe side when viewed in the top-bottom direction, it is considered that the position where deflection is most likely to occur is slightly closer to the toe side than the geometrically central position FC.

When a shot is made with a metal club having the above-described head, a shot occurs near the shot position C, but when it is verified that a mark is formed when an average middle-tech golfer (ordinary golfer) makes 100 shots, a result is obtained that almost all shots are made at a height of 25mm or less (within 6 of the height of the scribed line 7) from the head front edge LE in the height direction. In addition, a result was obtained that almost all shots were made within 10mm of the toe side and the heel side with the shot position C as a center in the toe-heel direction (traces of shots were also found to be made somewhat more outside than 10 mm).

In the present invention, according to the above verification results, the region of the hitting surface R on which a normal golfer hits is defined as the effective hitting region R1, and a concave portion, which is a thin portion for reducing rigidity, is formed on the back surface of the front surface portion 5 so that the effective hitting region R1 is effectively deflected. Specifically, in the present invention, the sweet spot region R1 is defined as a region within a radius of 10mm (a circular region surrounded by a broken line) with the hitting position C as a center, and a thin portion (concave portion) having low rigidity is formed outside the sweet spot region (excluding the sweet spot region) to effectively deflect the sweet spot region R1.

The concave portion serving as the thin portion has the toe-side concave portion 21 provided on the toe side and the heel-side concave portion 22 provided on the heel side with respect to the effective striking area R1, and the effective striking area R1 inside both concave portions can be easily deflected by reducing the rigidity of the portions. At this time, if the geometric shape of the front portion is taken into consideration, the most easily deflected portion is in the vicinity of the geometric center position FC as described above, and therefore if the low-rigidity concave portion is formed at a position above the geometric center position FC, the easily deflected region is displaced upward, and the effective hitting region R1 cannot be deflected effectively. That is, the toe recess 21 and the heel recess 22, which are low rigidity portions, are preferably formed in a lower region of the front surface portion, specifically, at least in a lower region than the heel upper end position Pr of the ball striking surface R of the front surface portion 5 and below the geometrically central position FC so that the effective ball striking region R1 is easily deflected. Further, the depth D of the recess for achieving the lower rigidity is preferably 30% or less of the thickness T of the front portion because the strength as the front portion is reduced if it is too deep.

As shown in fig. 3, the toe-side concave portion 21 and the heel-side concave portion 22 of the present embodiment are respectively constituted by 3 curved grooves 21a, 21b, 21c and 22a, 22b, 22c on the front surface back surface so as not to include a region corresponding to the effective hitting region R1 on the front surface side. That is, the grooves are formed below the geometrically central position FC, the grooves 21a, 21b, and 21c are formed so as to be parallel to each other while being bent from the center position on the toe side to the center position on the bottom side, and the grooves 22a, 22b, and 22c are formed so as to be parallel to each other while being bent from the center position on the heel side to the center position on the bottom side. By forming 3 grooves in each of the grooves in this manner, the effective striking area R1 can be effectively deflected substantially uniformly by forming the grooves in a substantially symmetrical shape on the toe side and the heel side while effectively achieving a reduction in rigidity.

In the present embodiment, the toe concave portion 21 and the heel concave portion 22 are formed outside the toe side 15mm (outside the position indicated by the symbol Rt) and outside the heel side 15mm (outside the position indicated by the symbol Rh) with the ball striking position C as the center, in consideration of variations (large variations) in the ball struck in the toe-heel direction, in addition to the range of the effective ball striking region R1 described above, and the substantially elliptical region R2 larger than the effective ball striking region R1 is effectively deflected. That is, by forming the toe-side concave portion 21 and the heel-side concave portion 22 at positions not including the region R2, the elliptical region R2 larger than the effective striking region R1 can be effectively deflected without reducing the feeling of striking the ball and the strength, and the drop in the flight distance can be suppressed even if the striking position is slightly shifted in the toe-heel direction.

Since the toe-side depressed portion 21 and the heel-side depressed portion 22 are formed on the rear surface of the front surface portion 5 having the above-described configuration so as not to include the sweet spot region R1 defined within a radius of 10mm with the hitting position C as the center, the flexibility (rebound resilience) of the sweet spot region can be effectively improved, and the flight distance of the hit ball can be improved. In particular, in the present embodiment, since the formation position of each groove is shifted from the hitting position C by 15mm or more to the toe side and the sole side, the tolerance for mishit (misshot) is increased, and further, since no concave portion is formed in the R1 in the effective hitting region where a hit ball actually occurs, the fatigue strength and the feeling of hitting the ball at the hitting portion are not reduced, and the rebound performance is effectively improved, and when a miss hit occurs and a hit ball is made through the portion where the concave portion is formed, the miss hit can be perceived.

Here, a front surface portion in which concave portions (3 curved grooves 21a, 21b, 21c formed on the toe side and 3 curved grooves 22a, 22b, 22c formed on the heel side) having shapes as shown in fig. 3 are formed on the back surface of the front surface portion will be described while comparing CT value distributions of the front surface portion having the same structure and not formed with grooves.

The deflection of the front face portion is measured by a pendulum test of USGA (american golf association) as an index, and the deflection of the front face portion can be evaluated by a numerical value (CT value) called a feature time. Specifically, the elasticity of the position of the front portion can be evaluated by measuring the contact time when a predetermined sample is made to collide with the front portion, and if the CT value is high (the contact time is long), the contact time with the front portion at the time of hitting a ball is long, and it can be evaluated that the flexibility is excellent. That is, the higher the CT value is, the more the front portion is likely to be flexed, and the flight distance of the ball can be increased, and if the area of the front portion having a higher CT value is larger, it means that a stable shot is completed even if a slight deviation of the shot occurs.

In the front face portion, the CT value can be derived from the front position, and the size of the CT value and the overall distribution state can be obtained for each position. The CT value is also influenced by the material of the front surface portion, but is more influenced by the thickness of the front surface portion and the distance from the edge region. That is, the front portion itself can be easily deflected by reducing the thickness, and the region farthest from the edge region (the geometrically central position FC of the front portion) is easily deflected largely, so that the CT value in the vicinity of the geometrically central position FC is high.

In the present invention, as described above, since the toe-side concave portion 21 and the heel-side concave portion 22, which are thin portions, are formed on the toe side and the heel side so as not to include the effective striking area R1, the rigidity of the portions is reduced, and the CT value of the striking position C and the effective striking area R1, which is a peripheral area thereof, is increased.

Table 1 below shows the CT value distribution of the conventional front face portion in which the toe-side concave portion and the heel-side concave portion are not formed, and shows the actual measurement values and percentages. Table 1 shows the results of the distribution of CT values in an effective hitting region (range of height from U5 to U25, and range of toe (T) heel (H) direction from T10 to H10) of radius 10mm centering on the hitting position C (height position 15mm from the head front edge, indicated by U15) measured in units of 5mm, the results of measurements up to 20mm (T15, T20) on the toe side, and the results of measurements up to 15mm (H15) on the heel side. In addition, the heel side 20mm (H20) and the height 5mm (U5) do not show the measurement result because they are not proper shots such as a right oblique flight ball and a shaving ball.

TABLE 1

Table 2 below shows the CT value distribution of the front face portion according to the present invention in which the toe-side concave portion 21 and the heel-side concave portion 22 are formed as shown in fig. 3, which is the same as table 1, and shows the actual measurement values and percentages. The front surface portion obtained as a result of table 2 has the same structure as the front surface portion of table 1 except that the toe-side concave portion 21 and the heel-side concave portion 22 are formed.

TABLE 2

The CT value at the striking position C (height of 15mm from the front edge of the head, indicated by U15) of the conventional face part was 224.0 μ s, whereas the CT value at the striking position C of the present invention was 247 μ s, and the flexibility of the striking position C at which a ball actually struck was obtained was improved. In addition, with respect to the CT value (actually measured value) in the effective hitting region, the front surface portion of the present invention is equal to or more than that of the conventional front surface portion, and results of improved flexibility as a whole are obtained in the effective hitting region, and results of high CT values are obtained even at positions of 15mm and 20mm on the toe side and 15mm on the heel side. In the regions having heights of 10mm (U10) and 15mm (U15), the CT values on the toe side and the heel side of the hitting position C do not show a large decrease as in the conventional face part, and a result is obtained that the amount of change between the hitting positions C is small in the height range. That is, although a miss-hit that is not a large thickness hit occurs frequently when hitting the ball at the same height as the hitting position C (or at a position slightly below the hitting position C), since there is no large decrease in the CT value at the hitting position C at this position, the flight distance can be stabilized even if a miss-hit occurs.

Actually, trial tests were performed on the metal type golf club having the conventional front face portion and the metal type golf club having the front face portion of the present invention under the same conditions except for the groove of the front face portion. In order to obtain an evaluation of performance when a typical golfer hits a wrong shot (hits a shot at a position deviated from the shot position C) within a range where the shot is likely to be hit, a trial test was conducted by hitting 4 balls at each position while changing the shot position while setting the head speed to be the same using a robot tester, and the average value was obtained. The hitting positions are 4 positions of the hitting position C, 5mm downward from the hitting position C, 10mm toward the toe side from the hitting position C, and 10mm toward the heel side from the hitting position C.

In the golf club having the front face part of the present invention, if the average value of the whole is compared, the flying distance is improved by about 5 yards compared with the conventional golf club. In addition, even if the deviation occurs in the range of about 3 yards with respect to the center line (target direction) with respect to the left-right direction in the present invention, the deviation occurs in the range of about 5 yards in the golf club having the conventional face portion, and the result of stabilizing the directivity is obtained.

As shown in tables 1 and 2, even in any of the hitting position C, 5mm downward from the hitting position C, 10mm toward the toe side from the hitting position C, and 10mm toward the heel side from the hitting position C, since the CT value of the present invention is higher than that of the conventional one, it is considered that the flying distance as a whole is improved. The reason why the variation in the left-right direction is small and the directivity is stable is considered as follows.

In a wood-type golf club such as queen wood, a so-called engagement effect is obtained because an arc portion (arc in the toe-heel direction) is formed on the front surface, but a slight engagement effect is considered to be obtained even on the front surface of a metal-type golf club. This engagement effect is such that, when a ball is struck by a point away from the center of gravity of the head, a torque is generated around the center of gravity, and when a ball is struck by the toe side, a right-hand kick occurs with respect to the center line, and when a ball is struck by the heel side, a left-hand kick occurs with respect to the center line. In such a striking direction, the engagement effect acts, and when a ball is struck on the toe side, the left-hand (draw) spin acts on the ball, and when a ball is struck on the heel side, the right-hand (fade) spin acts on the ball, and the ball is returned to the center line direction. As described above, in the present invention, since the CT value is increased in the sweet spot region, the flight distance performance is improved (the drop position of the shot is elongated) compared with the conventional one even if the shot is deviated, and it is considered that the engagement effect sufficiently acts to easily return the shot to the center.

Next, another embodiment of the present invention will be explained.

In the following embodiments, configuration examples in which the shape of the concave portion formed on the back surface of the front surface portion is variously modified are shown, and only the back surface of the front surface portion is shown. The same components as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

Fig. 4 is a view showing embodiment 2 of the present invention.

In the configuration of the above embodiment, the concavity is formed on the back surface of the front surface portion, so that the flexibility of the sweet spot region is effectively improved without making the front surface portion heavy.

For example, as shown in fig. 4, a rib 25 may be formed in the toe-heel direction at a position above the effective striking area R1 to increase the rigidity of the peripheral portion, facilitate flexure between the increased portion and the sole portion 1b, and increase the flexibility of the effective striking area R1. The rib may be formed continuously in the toe-heel direction, or may be formed in a plurality of parts, and the shape, the forming position, and the like of the rib may be appropriately changed.

Fig. 5(a) to (c) are views showing embodiments 3 to 5 of the present invention.

Although the toe-side concave portion 21 and the heel-side concave portion 22 of the above embodiment are each formed of 3 curved narrow grooves, as shown in fig. 5(a), the widths of the curved grooves 31a, 31b, 31c and the curved grooves 32a, 32b, 32c forming the toe-side concave portion 31 and the heel-side concave portion 32 may be increased. By widening the groove width in this manner, the rigidity of the region is further reduced, and the flexibility of the sweet spot region R1 can be improved. At this time, the peripheral edge region of each of the grooves constituting the toe-side concave portion 31 and the heel-side concave portion 32 is made less rigid by being deepened or widened as it moves outward, so that the vicinity of the hitting position C at the center can be greatly deflected, and the flight distance can be further increased.

In addition, when the grooves are formed as the recessed portions, the width thereof also affects the grooves, but as shown in fig. 5(b) and (c), the effect of effectively improving the flexibility of the effective hitting region R1 can be obtained by forming 2 or more grooves. Further, the shape of the groove can be appropriately deformed such as bending in the vertical direction as shown in fig. 5 (c).

Fig. 6(a) to (c) are views showing embodiments 6 to 8 of the present invention.

In each of the embodiments shown in fig. 5, the grooves constituting the toe-side concave portion 31 and the heel-side concave portion 32 are curved, but the grooves 41a, 41b, and 41c and the grooves 42a, 42b, and 42c constituting the toe-side concave portion 41 and the heel-side concave portion 42 may be formed curved as shown in fig. 6(a), or may be formed straight in the vertical direction or in an inclined direction as shown in fig. 6(b) and (c).

Fig. 7(a) to (c) are views showing embodiments 9 to 11 of the present invention.

As shown in fig. 7(a), the grooves 51a, 51b, 51c and the grooves 52a, 52b, 52c constituting the toe-side concave portion 51 and the heel-side concave portion 52 may be formed along the horizontal direction, or the horizontal grooves 52a, 52b, 52c and the vertical groove 52d may be combined as in the heel-side concave portion 52 of fig. 7 (b). Alternatively, as in the toe-side concave portion 51, the substantially horizontal grooves 51a and 51b and the curved groove 51c may be combined. As shown in fig. 7(c), the grooves 51a and 52a may be combined with the concave portions 51b and 52b recessed within a certain range, or the grooves 51c and 52c may connect the grooves.

Fig. 8(a) and (b) are views showing embodiments 12 and 13 of the present invention.

As shown in fig. 8(a), the toe-side concave portion 61 and the heel-side concave portion 62 may be formed of concave portions 61a and 62a recessed within a certain range. At this time, since the depth of each concave portion becomes deeper as it moves outward, the vicinity of the hitting position C as the center can be greatly deflected, and the flight distance can be further increased.

As shown in fig. 8(b), the toe-side concave portion 71 and the heel-side concave portion 72 may be configured by forming a plurality of circular concave portions 71a and 72 a. At this time, by increasing the number of concave portions or increasing the depth as the ball moves outward, the vicinity of the hitting position C, which is the center, can be greatly deflected, as in the configuration of fig. 8 (a).

Although the metal type golf club and the head thereof according to the present invention have been described above, the present invention is characterized in that a thin wall portion (concave portion) for reducing rigidity is provided on the front surface so that the effective hitting region R1 of the front surface portion can be easily deflected in consideration of a deviation from the hitting position C at the time of hitting a ball with a normal swing. The structures of the toe-side concave portion and the heel-side concave portion, which are the concave portions, are exemplified, and the shapes thereof can be appropriately deformed. At this time, the flexibility of the sweet spot region R1 can be appropriately changed by changing the depth, size (width, length), and formation position. For example, the structure and the formation position of the recess constituting the thin portion can be appropriately changed by thinning the recess in a certain range, forming the recess in a groove shape, or combining these in a region other than the effective hitting region R1. The sweet spot region R1 may be formed on the toe side and the heel side as in the above-described embodiment, or may be formed so as to be located on the upper side or the lower side with respect to the sweet spot region R1 in some cases.

Claims (8)

1. A golf club head having a front face part having a striking face formed with a scribed line, a thin part being formed on the back face of the front face part,

forming the thin-walled portion so as not to include a region defined as an effective striking area within a radius of 10mm from a striking position (C) as a center when the striking position (C) is defined as the striking position at a position 15mm from a front edge of the head on a perpendicular line passing through a geometrically central position of the front portion,

the thin portion has a toe-side concave portion provided on a toe side of the effective hitting region and a heel-side concave portion provided on a heel side of the effective hitting region, and the toe-side concave portion and the heel-side concave portion are formed in a region below a heel-side upper end position of the hitting surface of the front portion.

2. The golf club head according to claim 1, wherein the toe side concavity and the heel side concavity are formed more outside than the toe side 15mm and more outside than the heel side 15mm centering on the ball striking position (C).

3. The golf club head according to claim 1 or 2, wherein the toe side concave portion and the heel side concave portion are formed closer to a lower region than a geometrically central position of the front face portion.

4. The golf club head according to any one of claims 1 to 3, wherein the toe side concave portion and the heel side concave portion each have 2 or more grooves.

5. The golf club head according to any one of claims 1 to 4, wherein the toe-side concave portion and the heel-side concave portion are formed in a substantially symmetrical shape.

6. The golf club head according to any one of claims 1 to 5, wherein the toe side concave portion and the heel side concave portion are made less rigid as moving toward the toe side outer side and the heel side outer side, respectively.

7. The golf club head according to any one of claims 1 to 6, wherein a rib is formed on an inner face of the front face portion in a toe-heel direction at a position above the effective hitting region.

8. A metal type golf club having the golf club head according to any 1 of claims 1 to 7.

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