JP7047315B2 - Wood type golf club head - Google Patents

Description

The present invention relates to a wood-type golf club head, and more particularly to a wood-type golf club head capable of improving the flight distance and directional variation of a hit ball.

When a ball is hit with the face of a golf club head having a loft angle, the ball has a backspin based on the frictional force with the face. It was generally considered that the larger the loft angle and the larger the coefficient of friction of the face surface, the larger the backspin amount of the ball.

However, as a result of various experiments, in a golf club head having a small loft angle such as a wood type golf club head, the larger the friction coefficient of the face, the lower the backspin amount, and the smaller the friction coefficient of the face, the more back. It has been confirmed that the amount of spin increases (see Patent Document 1). It is believed that such a phenomenon is affected by the recoil generated in the ball.

In general, recoil is a kind of restoring force that tries to restore the elastic twist generated inside the golf ball by contact with the face, and when this recoil is strongly expressed, the amount of backspin decreases. That is, in a golf club head having a small loft angle, the larger the coefficient of friction of the face, the more the recoil action is relatively enhanced, and the amount of backspin of the ball is reduced. On the contrary, in a golf club head having a small loft angle, the smaller the coefficient of friction of the face, the more the action of recoil is suppressed and the amount of backspin of the ball increases.

Patent Document 2 proposes a golf club head utilizing the above-mentioned phenomenon. This golf club head has a ten-point average roughness smaller than 1.5 (μm) in the region on the face that is on the crown side of the sweet spot of the face, and is on the sole side of the sweet spot of the face. The ten-point average roughness of the region under the face is 1.5 to 10 (μm).

Generally, when the ball is hit in the area on the face, the backspin amount of the ball is usually reduced by the gear effect. However, according to the wood-type golf club head described in Patent Document 2, since the friction coefficient of the region on the face of the face is small, the action of recoil is weakened and the backspin amount of the ball is significantly reduced. Can be suppressed.

Further, when the ball is hit in the region under the face, the backspin amount of the ball is usually increased by the gear effect. However, according to the wood-type golf club head described in Patent Document 2, since the friction coefficient in the region under the face of the face is large, the recoil action is strengthened and the significant increase in the backspin amount of the ball is suppressed. can do.

As described above, according to the golf club head of Patent Document 2, even when the hitting points are scattered above and below the face, the flight distance of the hit ball can be stabilized.

Japanese Unexamined Patent Publication No. 2000-5352 Japanese Unexamined Patent Publication No. 2004-201787

However, even in the wood type golf club head of Patent Document 2, there is a problem that the flight distance of the hit ball tends to vary when the hitting point deviates in the toe-heel direction (left-right direction) of the face.

The present invention has been devised in view of the above problems, and its main object is to provide a wood-type golf club head capable of improving the flight distance of a hit ball and the variation in directionality.

The present invention is a wood-type golf club head having a face portion having a face for hitting a ball, wherein the face includes a first region and a second region, and the first region is a toe of the face. The second region is located in the center of the heel direction and on the upper side of the face, and the second region is adjacent to the toe side, the heel side, and the lower side of the first region in the front view of the face. It is formed in a U shape, and the surface roughness of the second region is formed to be larger than the surface roughness of the first region.

In another aspect of the invention, it is desirable that the toe side and heel side of the second region extend to the upper edge of the face.

In another aspect of the present invention, it is desirable that the boundary between the first region and the second region extends in a convex arc shape toward the lower side of the face in the front view of the face.

In another aspect of the present invention, it is desirable that the lowermost position of the first region is located at a height of ½ of the maximum height of the face or above it.

In another aspect of the invention, it is desirable that the lowest position of the first region is located at a height of 2/3 of the maximum height of the face or below it.

In another aspect of the present invention, the moment of inertia about the vertical axis passing through the center of gravity of the head is 3500 to 6000 (g · cm ² ) in a reference state in which the head is placed on a horizontal plane at a specified lie angle and loft angle. It is desirable that the bulge radius of the face is 10 to 16 inches.

In another aspect of the present invention, the difference in arithmetic mean roughness Ra is 0.5 μm or more and the difference in maximum height roughness Rz is 5 μm or more between the first region and the second region. Is desirable.

In another aspect of the present invention, the difference in arithmetic mean roughness Ra between the first region and the second region is 0.5 to 4 μm, and the difference in maximum height roughness Rz is 5 to 15 μm. It is desirable to have it.

According to the wood type golf club head of the present invention, the face includes a first region and a second region. The first region is located at the center of the face in the toe-heel direction and on the upper side of the face. The second region is formed in a U shape in front view of the face so as to be adjacent to the toe side, heel side, and lower side of the first region. The surface roughness of the second region is formed to be larger than the surface roughness of the first region.

According to the wood type golf club head of the present invention, since the first region has a low friction surface, when the ball is hit at the center and the upper side of the face, the action of the recoil is weakened, and thus the backspin amount. It is possible to suppress a significant decrease in. Further, according to the wood type golf club head of the present invention, since the second region has a surface with high friction, when the ball is hit on the lower side of the face, the action of the recoil is strengthened and the backspin amount of the ball is increased. Can be suppressed from a large increase in.

Further, according to the wood type golf club head of the present invention, since the second region having a high friction surface constitutes the toe side and the heel side of the face, the ball is hit on the toe side or the heel side of the face. When this is done, the action of the recoil can be strengthened and a significant increase in the amount of side spin of the ball can be suppressed. This reduces the bending of the ball in the left-right direction and suppresses variations in flight distance.

As described above, according to the wood type golf club head of the present invention, it is possible to stabilize the flight distance of the hit ball even when the hitting points are scattered not only above and below the face but also to the left and right.

It is a perspective view of the wood type golf club head of this embodiment. It is a front view of the wood type golf club head of this embodiment. It is a top view of the wood type golf club head of this embodiment. FIG. 2 is a cross-sectional view taken along the line AA of FIG. (A) is a front view of the golf club head, and (B) is a partial cross-sectional view of the E1 line. (A) to (C) are plan views of the golf club head for explaining the toe side hit and the heel side hit of the face. It is a front view of the wood type golf club head of this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The specific configurations shown in the embodiments and drawings detailed below are for understanding the contents of the present invention, and the present invention is not limited to those specific configurations. not.

1 to 4 are a perspective view, a front view, a plan view, and a sectional view taken along line AA of FIG. 3 of the golf club head 1 of the present embodiment (hereinafter, may be simply referred to as a “head”). Each is shown. Further, FIGS. 1 to 3 show the head 1 in the reference state.

[Head reference state]
The reference state is a state in which the head 1 is placed on the horizontal plane HP while being maintained at its loft angle α (FIG. 4) and lie angle β (FIG. 2). In the reference state, the shaft axis center line CL of the head 1 is arranged in an arbitrary vertical plane VP. The horizontal direction y along the vertical plane VP is the toe-heel direction of the head 1, and the horizontal direction x orthogonal to the vertical plane VP is the front-back direction of the head 1. The vertical direction z orthogonal to both x and y is defined as the vertical direction of the head 1. Unless otherwise noted, head 1 should be understood as being placed in reference state.

[Basic head configuration]
As shown in FIGS. 1 to 4, the head 1 of the present embodiment is a wood type having a hollow portion i inside, and is more preferably configured as a driver. The wood-shaped head 1 includes at least a brassie (# 2), a spoon (# 3), a buffy (# 4) and a creek (# 5) in addition to the driver (# 1). The wood type head 1 includes a head having a similar shape even if the count or the name is different from that listed above, for example, a utility type. In a preferred embodiment, the loft angle α of the wood type head is, for example, 35 degrees or less, more preferably 26 degrees or less.

The head 1 of the present embodiment is made of, for example, a metal material. The metal material is not particularly limited, but is preferably one or more, for example, stainless steel, maraging steel, pure titanium, titanium alloy, aluminum alloy, or the like. However, it goes without saying that elements other than metal materials such as fiber reinforced resin may be partially used.

The head 1 of the present embodiment includes, for example, a face portion 2, a crown portion 3, a sole portion 4, and a side portion 5. The hollow portion i of the head 1 is defined by a face portion 2, a crown portion 3, a sole portion 4, and a side portion 5.

The front surface of the face portion 2 constitutes a face 2a, which is a hitting surface for hitting a ball. A score line (groove) extending in the toe-heel direction may be formed on the face 2a according to the custom (not shown).

As shown in FIG. 2, the face 2a is defined by an upper edge e1, a lower edge e2, a toe side edge e3 and a heel side edge e4. Each of these edges e1 to e4 is defined by the ridgeline if a clear ridgeline is identifiable. On the other hand, when such a clear ridgeline cannot be identified, as shown in FIG. 5A, a large number of planes E1, E2 ... Including a straight line N (FIG. 4) connecting the head center of gravity G and the sweet spot SS. As shown in FIG. 5B, the radius of curvature r of the outer surface contour line Lf of the face is measured from the sweet spot SS side toward the outside of the face, and the value is 200 mm (about) for the first time. The position of 7.874 inches) is defined as each of the edges e1 to e4. The outer surface contour line Lf of the face is defined as having no score line (with the score line smoothly filled).

As shown in FIGS. 1 and 4, the crown portion 3 is connected to the face portion 2 to form the upper surface of the head. For example, a hosel portion 6 may be provided on the heel side of the crown portion 3. The hosel portion 6 is formed in a cylindrical shape having a shaft insertion hole 6a so that a shaft (not shown) can be fixed. The shaft center line of the shaft insertion hole 6a corresponds to the shaft shaft center line CL.

As shown in FIG. 4, the sole portion 4 is connected to the face portion 2 to form the bottom surface of the head.

As shown in FIGS. 1 to 3, the side portion 5 connects the crown portion 3 and the sole portion 4. The toe side and heel side of the side portion 5 are connected to the toe side and heel side of the face portion 2, respectively.

The head 1 of the present embodiment has a large volume, preferably 200 cm ³ or more, more preferably 250 cm ³ or more, and further preferably 300 cm ³ or more. In such a head 1, the moment of inertia about the vertical axis passing through the center of gravity G of the head (hereinafter, such a moment of inertia is referred to as "left and right moment of inertia") becomes large in the reference state. In the present embodiment, it is desirable that the head 1 has a left and right moment of inertia of 3500 to 6000 (g · cm ² ). The head 1 having a large moment of inertia on the left and right is less likely to exhibit the gear effect on the left and right.

As shown in FIG. 6A, the left and right gear effect means that when the ball is hit on the toe side or the heel side of the face, the head makes a slight rotation around the vertical axis and the ball has a face. This is a phenomenon in which a side spin in the direction opposite to that of the head is generated due to friction with the ball, which causes bending such as a hook or a slice in the hit ball. This side spin causes the ball to deteriorate in direction with respect to the target flight line direction. However, in a head having a large left and right moment of inertia, even if the hitting point shifts to the toe side or the heel side of the face, the above-mentioned rotational behavior of the head becomes small, so that the side spin amount of the ball decreases and the direction of the hitting ball Can be stabilized.

As shown in FIG. 3, it is desirable that the bulge radius R of the face 2a is 10 to 16 inches (254 to 406.4 mm) in order to further stabilize the direction of the hit ball and suppress the decrease in the flight distance. .. The bulge radius R is a radius of curvature that defines the horizontal bulge of the face 2a toward the outside of the head, that is, the magnitude of the “bulge”.

As shown in FIG. 6B, the original purpose of the bulge is to launch the ball to the right or left side of the target flight line when the hitting point of the ball shifts to the toe side or the heel side of the face 2a. To let you. As mentioned above, when hitting off-center, the ball hooks or slices due to the left and right gear effects. However, by directing the launch direction of the ball in the direction opposite to the direction in which the ball will bend in advance by the bulge, both are canceled out and the directionality of the ball with respect to the target flight line direction is enhanced.

On the other hand, as shown in FIG. 6C, the head having a large moment of inertia on the left and right has a small influence of the gear effect on the left and right, and the side spin of the ball is small. Therefore, if the bulge radius R is small, the ball launched to the left and right cannot return to the target flight line direction. From this point of view, in this embodiment, the bulge radius R is set to 10 to 16 inches.

As shown in FIG. 2, in the head 1 of the present embodiment, the face 2a includes a first region 10 and a second region 20.

The first region 10 is located at the center of the face 2a in the toe-heel direction and on the upper side of the face 2a. More specifically, the first region 10 extends from the upper edge e1 of the face 2a to the lower side of the face 2a. The first region 10 is terminated without reaching the lower edge e2 of the face 2a, the toe side edge e3, and the heel side edge e4.

The second region 20 is formed as a U-shaped region in the front view of the face 2a so as to be adjacent to the toe side, heel side, and lower side of the first region 10. In the present embodiment, the second region 20 extends from the toe side of the upper edge e1 of the face 2a to the heel side of the upper edge e1 of the face 2a along the first region 10, and the first region 10 is towed. Surrounded from the side, bottom and heel side. The toe side and heel side of the second region 20 extend to, for example, the upper edge e1 of the face 2a. Further, the second region 20 reaches, for example, the toe side edge e3, the heel side edge e4, and the lower edge e2, and essentially forms the remaining region excluding the first region 10 of the face 2a.

In the head 1 of the present embodiment, the surface roughness of the second region 20 is formed to be larger than the surface roughness of the first region 10. Therefore, the second region 20 has a higher coefficient of friction than the first region 10.

According to the head 1 of the present embodiment, when the ball is hit at the center and the upper side of the face 2a of the head 1, the ball comes into contact with the first region 10 having a relatively low coefficient of friction. Therefore, the action of the recoil of the ball is weakened, and it is possible to suppress a significant decrease in the amount of backspin.

Further, according to the head 1 of the present embodiment, when the ball is hit on the lower side of the face 2a of the head 1, the ball comes into contact with the second region 20 having a relatively high coefficient of friction. Therefore, the action of the recoil of the ball is strengthened, and it is possible to suppress a large increase in the backspin amount.

As described above, according to the head 1 of the present embodiment, since the change in the backspin amount due to the so-called vertical gear effect is suppressed, the hit ball is hit even when the hitting points are scattered in the vertical direction of the face 2a. The flight distance is stable.

Here, if the position 10P on the lowermost side of the first region 10 is too low, the ball comes into contact with the first region 10 when hit on the lower side of the face 2a, the backspin amount increases excessively, and the ball is hit. There is a risk of impairing the flight distance. From this point of view, as shown in FIG. 7, the lowermost position 10P of the first region 10 is positioned at a height position of 1/2 of the maximum height H of the face 2a or above it. Is desirable. The maximum height of the face 2a is defined as the vertical height from the horizontal plane HP to the highest position of the upper edge e1 of the face 2a.

On the contrary, if the position 10P on the lowermost side of the first region 10 is too high, the ball comes into contact with the second region 20 when hit on the upper side of the face 2a, the backspin amount is excessively reduced, and the ball is also hit. There is a risk of impairing the flight distance. From this point of view, it is desirable that the lowermost position 10P of the first region 10 is located at a height of 2/3 of the maximum height H of the face 2a or below it. The sweet spot SS of the head is also preferably located between the height position of 1/2 of the maximum height H of the face 2a and the height position of 2/3 of the maximum height H of the face 2a. .. In a particularly preferable embodiment, it is preferable that the sweet spot SS of the head and the position 10P on the lowermost side of the first region 10 are provided at the same height.

Further, as shown in FIG. 7, the width CW in the toe-heel direction of the first region 10 is preferably in the range of 40% to 60% of the maximum width FW in the toe-heel direction of the face 2a.

Further, according to the head 1 of the present embodiment, the entire area on the toe side and the heel side of the face 2a is formed as the second region 20. Therefore, when the ball is hit on the toe side or the heel side of the face 2a of the head 1, the ball comes into contact with the second region 20 having a relatively high coefficient of friction. Therefore, the action of the recoil of the ball is strengthened, and the side spin can be adjusted to an appropriate amount by the left and right gear effects. This reduces the bending of the ball in the left-right direction and suppresses variations in flight distance. Such an action is particularly effective in the head 1 having a large left and right moment of inertia and a large bulge radius as in the present embodiment.

In a preferred embodiment, it is desirable that the boundary 30 between the first region 10 and the second region 20 extends in a convex arc shape toward the lower side of the face 2a in the front view of the face 2a. In the present embodiment, the boundary 30 extends smoothly along the toe side edge e3, the lower edge e2, and the heel side edge e4 of the face 2a. However, the present invention is not limited to such an aspect, and the boundary 30 can be changed to various aspects. For example, the boundary 30 may be V-shaped.

As described above, according to the head 1 of the present embodiment, it is possible to stabilize the flight distance of the hit ball even when the hitting points are scattered not only in the vertical direction of the face 2a but also in the horizontal direction. It works.

As described above, in the head 1 of the present embodiment in which the left and right moments of inertia are large, the action of the left and right gear effects is weakened, but when the hitting point is largely deviated from the toe side or the heel side of the face 2a. , The amount of side spin tends to increase. From such a viewpoint, it is desirable that the surface roughness of the second region 20 gradually increases from the central portion of the face 2a in the toe-heel direction toward the toe side and the heel side. According to such an aspect, even when the hitting point is largely deviated from the toe side or the heel side of the face 2a, the action of the recoil can be further strengthened, the side spin can be appropriately adjusted, and the left and right bending can be reduced.

The surface roughness of the first region 10 and the second region 20 can be evaluated by various parameters, and for example, various surface roughness parameters specified in JIS-B-0601 can be used.

As the surface roughness, for example, the arithmetic mean roughness Ra may be used. For example, it is desirable that the difference in arithmetic mean roughness Ra between the first region 10 and the second region 20 is 0.5 μm or more. When the difference in the arithmetic mean roughness Ra is less than 0.5 μm, the surface roughness of the first region 10 and the second region 20 approaches the same, so that the effect of suppressing the variation in the flight distance when the hitting points vary is effective. It may not be obtained sufficiently. On the other hand, if the difference in the arithmetic mean roughness Ra is too large, it may deviate from the range of the golf rule. From this point of view, the difference in arithmetic mean roughness Ra between the first region 10 and the second region 20 is more preferably in the range of 0.5 to 4 μm, and further preferably in the range of 1 to 4 μm. Is desirable.

The arithmetic average roughness Ra of the first region 10 is not particularly limited, but is preferably about 1 to 3 μm.

Further, as the surface roughness, the maximum height roughness Rz may be used together with the arithmetic average roughness Ra or instead of the arithmetic average roughness Ra. For example, it is desirable that the difference in maximum height roughness Rz between the first region 10 and the second region 20 is 5 μm or more. When the difference in the maximum height roughness Rz is less than 5 μm, the surface roughness of the first region 10 and the second region 20 approaches the same level, so that the effect of suppressing the variation in the flight distance when the hitting points vary is sufficient. May not be obtained. On the other hand, if the difference in the maximum height roughness Rz is too large, it may deviate from the range of the golf rule. From this point of view, it is desirable that the difference in average height roughness Rz between the first region 10 and the second region 20 is more preferably 5 to 15 μm, still more preferably 7 to 13 μm.

The maximum height roughness Rz of the first region 10 is not particularly limited, but is preferably about 10 to 18 μm.

The first region 10 and the second region 20 can be easily formed, for example, by performing shot blasting, polishing, or the like under different processing conditions.

Although the embodiments of the present invention have been described in detail above, it goes without saying that the present invention is not limited to the above-described embodiments and can be changed to various embodiments. In particular, each embodiment should not be rigorously understood as being independent of each other. For example, embodiments obtained by substituting some elements of one embodiment with the elements described in another embodiment should be understood as the scope of the present invention.

In order to confirm the effect of the present invention, a wood-type golf club head having a hollow structure made of titanium alloy having different surface roughness of the face was prototyped based on the specifications of FIGS. 1 to 4 and Table 1. A batting test was conducted. The common specifications of the wood type golf club used in the test are as follows.
Club total length: 45 inches Head volume: 460 cm ³
Loft angle: 10 degrees Moment of inertia on the left and right of the head: 4000 g ・ cm ²
Bulli radius: 12 inches Maximum face height H: 54 mm
Width of 1st region CW / Maximum width of face FW: 64%

For the surface roughness (Ra, Rz) of the face, the product name "INFINITE FOCUS optical 3D Measurement Device G4f" manufactured by Alicona was used, and three points (arbitrary) were measured in each area, and the average value thereof is shown. rice field.

In the hitting test, each golf club is attached to a swing robot, the head speed is adjusted to 45 m / s, and six balls are hit at a predetermined position on the face, and the average flight distance and backspin amount are obtained. It was measured. The ball hitting position of the face is as follows.
Reference impact: Face center (upper and lower sides of the face and intermediate position in the toe / heel direction)
5mm upper striking: 5mm above the face center 10mm upper striking: 10mm above the face center 5mm lower striking: 5mm below the face center The results of the test are shown in Table 1.

As a result of the test, it was confirmed that the head of the example suppressed the variation in the flight distance as compared with the comparative example.

Next, by changing the surface roughness, the left and right moments of inertia, and the bulge radius of the second region shown in Table 2, the hit ball is hit at a position 20 mm toe side and a position 20 mm heel side from the face center, respectively. The amount of side spin and the amount of deviation of the hit ball in the left-right direction with respect to the target flight line direction were measured.
The test results are shown in Table 2.

As a result of the test, it was confirmed that the head of the example was significantly improved in the direction of the hit ball as compared with the comparative example.

1 Wood type golf club head 2 Face part 2a Face 10 1st area 10P Lowermost position of 1st area 20 2nd area 30 Boundary e1 Upper edge of face H Maximum height of face R bulge radius

Claims (5)

A wood-type golf club head with a face that has a face that hits the ball.
The face includes a first region and a second region.
The first region is located at the center of the face in the toe-heel direction and on the upper side of the face.
The second region is formed as a U-shaped region in the front view of the face so as to be adjacent to the toe side, heel side, and lower side of the first region.
The second region extends from the toe side of the upper edge of the face to the heel side of the upper edge of the face along the first region, whereby the first region is on the toe side, the lower side and the heel side. Surrounded from the heel side,
The toe side and heel side of the second region each extend to the upper edge of the face.
The second region reaches the toe side edge, the heel side edge and the lower edge of the face, and forms the remaining region excluding the first region of the face.
The surface roughness of the second region is formed to be larger than the surface roughness of the first region .
A wood-type golf club head having a difference in arithmetic mean roughness Ra of 0.5 to 4 μm and a difference in maximum height roughness Rz of 5 to 15 μm between the first region and the second region . The wood-type golf club head according to claim 1, wherein the boundary between the first region and the second region extends in a convex arc shape toward the lower side of the face in the front view of the face. The wood-type golf club head according to claim 1 or 2, wherein the position on the lowermost side of the first region is located at a height position of 1/2 of the maximum height of the face or above the height position thereof. The wood-type golf club head according to any one of claims 1 to 3, wherein the position on the lowermost side of the first region is located at a height of 2/3 of the maximum height of the face or below the height position. .. In the reference state where the head is placed on the horizontal plane with the specified lie angle and loft angle, the moment of inertia around the vertical axis passing through the center of gravity of the head is 3500 to 6000 (g · cm). ² )
The wood-type golf club head according to any one of claims 1 to 4, wherein the bulge radius of the face is 10 to 16 inches.

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