U.S. patent application number 14/874745 was filed with the patent office on 2016-06-16 for golf club head.
This patent application is currently assigned to Bridgestone Sports Co., Ltd.. The applicant listed for this patent is Bridgestone Sports Co., Ltd.. Invention is credited to Wataru BAN, Tadahiro NARITA.
Application Number | 20160166891 14/874745 |
Document ID | / |
Family ID | 56110165 |
Filed Date | 2016-06-16 |
United States Patent
Application |
20160166891 |
Kind Code |
A1 |
NARITA; Tadahiro ; et
al. |
June 16, 2016 |
GOLF CLUB HEAD
Abstract
A golf club head of the present invention includes a crown
portion, a face portion, and a hosel portion. The crown portion
includes a turbulence-promoting portion that extends from a heel
side to a toe side and a back side.
Inventors: |
NARITA; Tadahiro;
(Chichibu-shi, JP) ; BAN; Wataru; (Chichibu-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bridgestone Sports Co., Ltd. |
Tokyo |
|
JP |
|
|
Assignee: |
Bridgestone Sports Co.,
Ltd.
Tokyo
JP
|
Family ID: |
56110165 |
Appl. No.: |
14/874745 |
Filed: |
October 5, 2015 |
Current U.S.
Class: |
473/332 |
Current CPC
Class: |
A63B 53/0466 20130101;
A63B 2225/01 20130101; A63B 53/0408 20200801; A63B 2071/0694
20130101; A63B 60/006 20200801; A63B 53/02 20130101; A63B 53/0437
20200801 |
International
Class: |
A63B 53/04 20060101
A63B053/04; A63B 53/08 20060101 A63B053/08 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 10, 2014 |
JP |
2014-250300 |
Claims
1. A golf club head comprising a crown portion, a face portion, and
a hosel portion, wherein said crown portion includes a
turbulence-promoting portion that extends from a heel side to a toe
side and a back side.
2. The golf club head according to claim 1, wherein a region of
said crown portion on a side of said face portion with respect to
said turbulence-promoting portion is smoother than said
turbulence-promoting portion.
3. The golf club head according to claim 1, wherein said crown
portion includes at least one other turbulence-promoting portion on
the back side with respect to said turbulence-promoting
portion.
4. The golf club head according to claim 1, wherein said
turbulence-promoting portion extends in one of a line shape or a
band shape.
5. The golf club head according to claim 1, wherein an arithmetic
mean roughness Ra of said turbulence-promoting portion is 2 .mu.m
(inclusive) to 30 .mu.m (inclusive).
6. The golf club head according to claim 1, wherein a concave
portion is formed in an outer surface of said hosel portion on the
toe side.
7. The golf club head according to claim 1, wherein an angle
between a toe-heel direction and a virtual line that connects a
heel end and a sole end of said turbulence-promoting portion is 5
degrees (inclusive) to 50 degrees (inclusive).
8. The golf club head according to claim 1, wherein a region of
said crown portion on the back side with respect to said
turbulence-promoting portion is smoother than said
turbulence-promoting portion.
9. The golf club head according to claim 1, wherein said
turbulence-promoting portion extends from a base portion of said
hosel portion to a toe-side circumferential edge of said crown
portion.
10. The golf club head according to claim 1, wherein said
turbulence-promoting portion passes the back side of a top of said
crown portion.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a golf club head.
[0003] 2. Description of the Related Art
[0004] To improve the head speed of a golf club head at impact, a
measure of reducing the air resistance to the golf club head has
been proposed. For example, each of Japanese Patent Laid-Open No.
2013-538666, Japanese Patent Laid-Open No. 2009-000281, and
Japanese Utility Model Laid-Open No. 60-135153 discloses a golf
club head that reduces the air resistance by forming a plurality of
dimples.
[0005] Forming dimples has a predetermined effect for reducing the
air resistance. However, the air resistance does not decrease in
proportion to the area of dimple formation. If air resistance
reducing elements such as dimples are formed unnecessarily in a
wide area, the manufacture of the golf club head may become
complicated, or the appearance may be spoiled.
SUMMARY OF THE INVENTION
[0006] According to an aspect of the present invention, there is
provided a golf club head comprising a crown portion, a face
portion, and a hosel portion, wherein the crown portion includes a
turbulence-promoting portion that extends from a heel side to a toe
side and a back side.
[0007] Further features of the present invention will become
apparent from the following description of exemplary embodiments
(with reference to the attached drawings).
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of a golf club head according
to an embodiment of the present invention;
[0009] FIG. 2A is a view of the golf club head in FIG. 1 viewed
from the upper side;
[0010] FIG. 2B is a sectional view taken along a line I-I in FIG.
1;
[0011] FIG. 3A is a perspective view showing the section of a crown
portion taken along a line II-II in FIG. 2A;
[0012] FIGS. 3B and 3C are views showing other examples of the
structure of a turbulence-promoting portion;
[0013] FIGS. 4A and 4B are explanatory views of an air resistance;
and
[0014] FIG. 5 is an explanatory view of another example.
DESCRIPTION OF THE EMBODIMENTS
[0015] FIG. 1 is a perspective view of a golf club head 10
according to an embodiment of the present invention. FIG. 2A is a
view of the golf club head 10 viewed from an upper side. FIG. 2A is
a view showing the golf club head 10 viewed from the upper side in
a case where the golf club head 10 is grounded according to a
predetermined lie angle and a predetermined loft angle.
[0016] The golf club head 10 forms a hollow member. The peripheral
walls of the golf club head 10 constitute a face portion 11 that
forms a face (striking face), a crown portion 12 that forms the
upper portion of the golf club head 10, a sole portion 13 that
forms the bottom portion of the golf club head 10, and a side
portion 14 that forms the portion between the crown portion 12 and
the sole portion 13. A turbulence-promoting portion 16 to be
described later is formed on the crown portion 12 as an air
resistance reducing element. The golf club head 10 also includes a
hosel portion 15 in which a shaft is inserted and fixed.
[0017] In FIGS. 1 and 2A, an arrow dl indicates the face-back
direction, and an arrow d2 indicates the toe-heel direction.
Normally, the face-back direction is to a target line direction
(target direction of a shot). The toe-heel direction can be defined
as, for example, the direction to connect the toe-side end and the
heel-side end of the sole portion 13 or the direction perpendicular
to the face-back direction.
[0018] The golf club head 10 is a golf club head for a driver.
However, the present invention is applicable to wood type golf club
heads including a fairway wood other than drivers, utility (hybrid)
golf club heads, and other golf club heads.
[0019] The golf club head 10 can be made of a metal material.
Examples of the metal material are a titanium-based metal (for
example, titanium alloy 6A1-4V-Ti), stainless steel, and a copper
alloy such as beryllium copper.
[0020] The golf club head 10 can be assembled by joining a
plurality of parts. For example, the golf club head 10 can be
formed from a body member and a face member. The body member forms
the peripheral portions including the crown portion 12, the sole
portion 13, the side portion 14, the hosel portion 15, and the face
portion 11. An opening is formed at part of the portion
corresponding to the face portion 11. The face member is joined to
the opening of the body member.
[0021] The hosel portion 15 will be described with reference to
FIG. 2B in addition to FIGS. 1 and 2A. FIG. 2B is a sectional view
taken along a line I-I in FIG. 1, that is, a sectional view taken
along a plane perpendicular to the axis of the hosel portion
15.
[0022] In this embodiment, the hosel portion 15 has a cylindrical
shape. However, the hosel portion 15 may have another tubular shape
such as an elliptic cylindrical shape. A concave portion 15a is
formed in the toe-side outer surface of the hosel portion 15. In
this embodiment, the concave portion 15a has a circular shape
(spherical shape). However, it may have a polygonal shape. Since
the concave portion 15a is provided, the separation position of an
airflow at impact can be changed to the back side as compared to a
case without the concave portion 15a, and the air resistance caused
by the presence of the hosel portion 15 can be reduced. The concave
portion 15a has a depth of, for example, 0.1 mm to 1 mm and a
diameter of, for example, 1 mm to 10 mm. The concave portion 15a
can be provided, in the outer surface of the hosel portion 15, at a
position within the hosel diameter in the face-back direction with
respect to the toe-side end where the airflow readily separates as
the center. The toe-side end position is preferable, as in this
embodiment. In this embodiment, only one concave portion 15a is
provided. However, a plurality of concave portions may be provided.
When providing a plurality of concave portions, the plurality of
concave portions can be provided in a direction parallel to the
axial direction of the hosel portion 15, in the face-back
direction, or in both directions.
[0023] The turbulence-promoting portion 16 will be described with
reference to FIG. 3A in addition to FIGS. 1 and 2A. FIG. 3A is a
perspective view showing the section of the crown portion 12 taken
along a line II-II in FIG. 2A.
[0024] The turbulence-promoting portion 16 generates small
turbulence on the surface, and suppresses separation of an airflow
flowing on the surface of the crown portion 12 from the surface of
the crown portion 12. When the turbulence-promoting portion 16 is
formed at a position where airflow separation from the crown
portion 12 readily occurs, the position where airflow separation
occurs can be moved to the back side. As a result, the air
resistance can be reduced.
[0025] In FIGS. 1 and 2A, the turbulence-promoting portion 16 is
indicated by a thick line so that its presence can easily be
visually recognized for descriptive convenience. However, visual
recognition of the actual turbulence-promoting portion 16 is
impossible or difficult depending on its structure. Conversely, the
turbulence-promoting portion 16 may have a visually emphasized
structure.
[0026] The turbulence-promoting portion 16 extends from the heel
side to the toe side and the back side. The length and the position
or area of the turbulence-promoting portion 16 can appropriately be
set. If the turbulence-promoting portion 16 is formed over a wide
area, the manufacture of the golf club head 10 may become
complicated, or the appearance may be spoiled. That is, the
turbulence-promoting portion 16 is preferably provided in a portion
effective for reducing the air resistance.
[0027] In this embodiment, the turbulence-promoting portion 16
extends in a line or band shape from the base of the hosel portion
15 to the toe-side edge of the crown portion 12, and crosses the
crown portion 12 obliquely in the toe-heel direction. When the
turbulence-promoting portion 16 crosses the crown portion 12 as in
this embodiment, an airflow flowing on the surface of the crown
portion 12 hardly separates throughout in the toe-heel
direction.
[0028] In this embodiment, the turbulence-promoting portion 16 has
an outer shape that bends a plurality of times. This is because the
turbulence-promoting portion 16 is formed following the positions
where the airflow separates from the crown portion 12. However, the
outer shape of the turbulence-promoting portion 16 may be
simplified to a linear shape or arcuate shape.
[0029] In a wood type golf club head having a general shape,
airflow separation from the crown portion at impact tends to occur
relatively from a face-side position on the heel side and from a
back-side position on the toe side. That is, a line that connects
the positions where the airflow separates obliquely crosses the
crown portion 12.
[0030] The turbulence-promoting portion 16 may be formed such that
an angle e between the toe-heel direction and a virtual line L1
that connects the heel end and the sole end becomes 5 degrees
(inclusive) to 50 degrees (inclusive), depending on the shape of
the golf club head, though. The turbulence-promoting portion 16 is
thus located in a region where the airflow separates in a case
without the turbulence-promoting portion 16, and the airflow
separation position can easily be moved to the back side.
[0031] In a wood type golf club head having a general shape,
airflow separation from the crown portion at impact tends to occur
at a position across over the top of the crown portion. In this
embodiment, the turbulence-promoting portion 16 passes the back
side of a top 12a of the crown portion 12. Hence, the
turbulence-promoting portion 16 is located in the region where the
airflow separates in a case without the turbulence-promoting
portion 16, and the airflow separation position can easily be moved
to the back side. Note that the top 12a can be defined as the
highest position of the crown portion 12 in a case where the golf
club head 10 is grounded according to a predetermined lie angle and
a predetermined loft angle.
[0032] The turbulence-promoting portion 16 according to this
embodiment is formed by roughening the surface of the crown portion
12. Out of the crown portion 12, a region S1 on the side of the
face portion 11 with respect to the turbulence-promoting portion 16
is smoother than the turbulence-promoting portion 16. The
turbulence-promoting portion 16 is thus prevented from being formed
over a wide area. In addition, since the region S1 of the crown
portion 12 on the side of the face portion 11 readily comes into
golfer's sight upon addressing, it may be possible to reduce
strange feeling or improve the appearance by forming a smoother
surface.
[0033] In this embodiment, out of the crown portion 12, a region S2
on the back side with respect to the turbulence-promoting portion
16 is also smoother than the turbulence-promoting portion 16. The
turbulence-promoting portion 16 is thus prevented from being formed
unnecessarily in a wide area. The surface roughness of the region
S1 and that of the region S2 may be equal in design.
[0034] As shown in FIG. 3A, the turbulence-promoting portion 16
according to this embodiment is formed by forming a number of
concave portions 16a in the surface of the crown portion 12. Each
concave portion 16a has a circular shape but may have a square
shape. A width W of the turbulence-promoting portion 16 in the
face-back direction can make the formation region of the narrow
turbulence-promoting portion 16 small. However, if the formation
region is too narrow, the turbulence promoting effect may decrease.
Hence, the width W is preferably 2 mm to 30 mm. The surface
roughness of the turbulence-promoting portion 16 is preferably, for
example, 2 .mu.m (inclusive) to 30 .mu.m (inclusive) as an
arithmetic mean roughness Ra.
[0035] The turbulence-promoting portion 16 can also be formed by a
method other than the concave portions 16a. For example, the
turbulence-promoting portion 16 can be formed by a plurality of
grooves. FIG. 3B shows an example. In the example of FIG. 3B, a
plurality of grooves 16b extending in the extending direction of
the turbulence-promoting portion 16 are formed. The
turbulence-promoting portion 16 can also be formed by, for example,
a plurality of linear convex portions or a number of point-like
convex portions. FIG. 3C shows an example. In the example of FIG.
3C, a plurality of linear convex portions 16c extending in the
extending direction of the turbulence-promoting portion 16 are
formed.
[0036] Examples of the method of forming the turbulence-promoting
portion 16 are casting, forging, laser machining, blasting, and
milling.
[0037] The effect of reducing the air resistance of the hosel
portion 15 by the turbulence-promoting portion 16 and the concave
portion 15a will be described next with reference to FIGS. 4A and
4B. FIGS. 4A and 4B are views schematically showing an airflow
acting on the golf club head 10 immediately before impact. FIG. 4A
shows a case where the turbulence-promoting portion 16 and the
concave portion 15a are absent as a comparative example. FIG. 4B
shows this embodiment.
[0038] As shown in FIG. 4A, immediately before impact, the airflow
to the golf club head 10 flows in the face-back direction. An
airflow flowing on the surface of the crown portion 12 changes to a
laminar flow on the side of the face portion 11 and separates
halfway. In addition, an airflow flowing on the toe side of the
hosel portion 15 separates near the toe-side end of the outer
surface of the hosel portion 15. The earlier the airflow separates,
the larger the air resistance to the golf club head 10 is.
[0039] In this embodiment shown in FIG. 4B, small turbulence is
generated by the turbulence-promoting portion 16, airflow
separation on the crown portion 12 delays, and the separation
position shifts to the back side. Additionally, because of the
presence of the concave portion 15a, separation of the airflow
flowing on the toe side of the hosel portion 15 also delays, and
the separation position shifts to the back side. As a result, the
air resistance to the golf club head 10 can be reduced.
[0040] As a detailed example, a case where the turbulence-promoting
portion 16 is formed by the plurality of grooves 16b, as shown in
FIG. 3B, was simulated on a computer. Note that FIG. 3B shows the
grooves 16b as easy to recognize, and their scale does not
necessarily match the actual scale. Each groove 16b was a groove
having a U-shaped section. The groove width was 0.2 mm, the groove
depth was 0.02 mm, and the pitch between the grooves was 0.4 mm.
The width W of the turbulence-promoting portion 16 was 12 mm, and
the surface roughness of the turbulence-promoting portion 16 was 5
.mu.m as the arithmetic mean roughness Ra. As a result, a model
with the turbulence-promoting portion 16 exhibited improvement of
the air resistance as compared to a model without the
turbulence-promoting portion 16.
[0041] To minimize the area of the turbulence-promoting portion 16,
the turbulence-promoting portion 16 is provided at the airflow
separation position described with reference to FIG. 4A.
[0042] The position of the turbulence-promoting portion 16 can be
determined by a simulation on a computer. That is, the airflow at
impact is simulated for a prototype of a golf club head without the
turbulence-promoting portion 16, and portions of the crown portion
12 where the airflow separates are specified. The
turbulence-promoting portion 16 is then designed so as to follow
and include the specified portions. A golf club head including the
turbulence-promoting portion 16 is thus manufactured. This makes it
possible to more easily reduce the air resistance to the golf club
head without forming the turbulence-promoting portion 16 over a
wide area.
Other Embodiments
[0043] In the above-described embodiment, only one
turbulence-promoting portion 16 is provided. However, a plurality
of turbulence-promoting portions 16 may be formed. FIG. 5 shows an
example. In the example of FIG. 5, a turbulence-promoting portion
16A and a turbulence-promoting portion 16B that are spaced apart in
the face-back direction are formed. Although two
turbulence-promoting portions are formed here, three or more
turbulence-promoting portions may be provided. However, the number
is preferably two from the viewpoint of preventing the
turbulence-promoting portions from unnecessarily increasing.
[0044] The turbulence-promoting portion 16A is the same as the
above-described turbulence-promoting portion 16. The
turbulence-promoting portion 16B can have the same structure as the
above-described turbulence-promoting portion 16. However, the
position is different, and the turbulence-promoting portion 16B is
formed on the back side with respect to the turbulence-promoting
portion 16A. If improvement of the separation position by the
turbulence-promoting portion 16A is insufficient, the
turbulence-promoting portion 16B can be provided at a portion where
the airflow separates relatively early. When the
turbulence-promoting portion 16B is provided, the airflow
separation position on the crown portion 12 can further be shifted
to the back side, and the air resistance can be reduced.
[0045] While the present invention has been described with
reference to exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all such modifications and
equivalent structures and functions.
[0046] This application claims the benefit of Japanese Patent
Application No. 2014-250300, filed Dec. 10, 2014 which is hereby
incorporated by reference herein in its entirety.
* * * * *