Patent Publication Number: US-10328319-B2

Title: Golf club head

Description:
TECHNICAL FIELD 
     The present invention relates to a golf club head. 
     BACKGROUND ART 
     In recent years, as disclosed in JP 5882522, for example, golf club heads have been proposed in which a raised portion is provided on the crown portion and a sloped surface is formed as a step between the raised portion and the portion rearward thereof. This configuration enables the height of the face portion to be raised by the height of the raised portion. Thus, the rebound performance of the face portion can be improved. Also, on the crown portion, only the raised portion is formed higher, and the portion rearward thereof is formed at a lower position than the raised portion, enabling the center of gravity of the head to be lowered. 
     JP 5882522 is an example of related art. 
     SUMMARY OF THE INVENTION 
     However, even with a golf club head having a structure such as described above, there is room for improvement in order to enhance the rebound performance, and it is desired to further increase the carry distance. The present disclosure was made in order to solve the above problem, and an object thereof is to provide a golf club head that is able to further enhance the rebound performance in a golf club head that has a raised portion formed on the crown portion. 
     A golf club head according to the present invention is provided with a face portion, a crown portion and a sole portion, the crown portion including a first region extending in a toe-heel direction along at least part of the face portion, a second region arranged further on a back side than the first region, a step region extending in the toe-heel direction between the first region and the second region and extending downward toward the second region from the first region side, and at least one rib formed on an inner wall surface of the crown portion and extending in a face-back direction from at least the step region to the second region. Note that the “face-back direction”, which is the direction in which the rib extends, need not be strictly in the face-back direction, and may slope at an angle. 
     In the above golf club head, the rib can be formed across the entire second region in the face-back direction. 
     In the above golf club heads, the rib can be formed to extend across the entire step region in the face-back direction. 
     In the above golf club heads, the rib can, in the first region, be formed to extend in the face-back direction, and to not reach a boundary between the crown portion and the face portion. 
     In the above golf club heads, the rib can be formed on a line extending in the face-back direction through a face center. 
     In the above golf club heads, the second region can be curved so as to be upwardly convex. 
     With a golf club head according to the present invention, the rebound performance can be further enhanced in a golf club head that has a raised portion formed on the crown portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a reference state of a golf club head according to the present embodiment. 
         FIG. 2  is a plan view of  FIG. 1 . 
         FIG. 3  is a cross-sectional view along an A-A line in  FIG. 2 . 
         FIG. 4A  is a diagram illustrating the boundary of a face portion. 
         FIG. 4B  is a diagram illustrating the boundary of the face portion. 
         FIG. 5  is a cross-sectional view showing the case where a rib is not provided in the golf club head of  FIGS. 1 to 3 . 
         FIG. 6  is a plan view showing another example of  FIG. 3 . 
         FIG. 7  is a plan view showing another example of  FIG. 2 . 
     
    
    
     EMBODIMENTS OF THE INVENTION 
     Hereinafter, an embodiment of a golf club head according to the present invention will be described, with reference to the drawings. 
     1. Overview of Golf Club Head 
       FIG. 1  is a perspective view of this golf club head,  FIG. 2  is a plan view of the head in a reference state, and  FIG. 3  is a cross-sectional view along an A-A line in  FIG. 2 . As shown in  FIGS. 1 to 3 , this golf club head (hereinafter, may be simply referred to as “head”)  100  is a wood-type golf club head having a hollow structure with an internal space, and a wall surface is formed by a face portion  1 , a crown portion  2 , a sole portion  3  and a hosel portion  4 . Specifically, the present invention is applicable to golf club heads such as utilities, fairway woods and drivers. 
     The face portion  1  has a face surface which is the surface that hits the ball, and the crown portion  2  adjoins the face portion  1  and constitutes the upper surface of the head  100 . The sole portion  3  mainly constitutes the bottom surface of the head  100 , and constitutes the outer peripheral surface of the head  100  other than the face portion  1  and the crown portion  2 . That is, besides the bottom surface of the head  100 , the region extending from the toe side of the face portion  1  around the back side of the head to the heel side of the face portion  1  is also part of the sole portion  3 . Furthermore, the hosel portion  4  is a region that is provided adjoining the heel side of the crown portion  2 , and has an insertion hole  41  into which the shaft (illustration omitted) of the golf club is inserted. A center axis line Z of this insertion hole  41  coincides with the axis line of the shaft. 
     Here, the reference state when setting the golf club head  100  on the ground will be described. First, as shown in  FIG. 2 , a state where the above center axis line Z is contained in a plane P 1  that is perpendicular to the ground and the head is placed on the ground at a predetermined lie angle and real loft angle is prescribed as the reference state. The above plane P 1  will be referred to as the reference perpendicular plane. Also, as shown in  FIG. 2 , the line of intersection between the above reference perpendicular plane P 1  and the ground will be referred to as the toe-heel direction, and the direction perpendicular to this toe-heel direction and parallel to the ground will be referred to as the face-back direction. Also, the direction that is orthogonal to the toe-heel direction and the face-back direction may be referred to as the up-down direction. 
     In the present embodiment, the boundary between the face portion  1  and the crown portion  2  and between the face portion  1  and the sole portion  3  can be defined as follows. That is, in the case where a ridgeline is formed therebetween, this ridgeline will be the boundary. On the other hand, in the case where a clear ridgeline is not formed, in each of cross-sections E 1 , E 2 , E 3  and so forth that contain a straight line N connecting a head center of gravity G and a sweet spot SS, as shown in  FIG. 4A , a position Pe at which a curvature radius r of a contour line Lf of the face outer surface first reaches 200 mm in a direction toward the face outer side from the sweet spot side, as shown in  FIG. 4B , will be the periphery of the face portion  1 , and this periphery is defined as the boundary with the crown portion  2  or the sole portion  3 . Note that the sweet spot SS is the point of intersection between the normal (straight line N) of the face surface that passes through the head center of gravity G and this face surface. 
     Also, in the present embodiment, the boundary between the crown portion  2  and the sole portion  3  can be defined as follows. That is, in the case where a ridgeline is formed between the crown portion  2  and the sole portion  3 , this ridgeline will be the boundary. On the other hand, in the case where a clear ridgeline is not formed therebetween, the contour when the head is set in the reference state and viewed from directly above the center of gravity of the head  100  will be the boundary. 
     Also, the head  100  can, for example, be formed with a titanium alloy (Ti-6Al-4V, Ti-8Al-1Mo-1V, etc.) having a specific gravity of substantially about 4.3 to 4.5. Also, apart from a titanium alloy, the head can also be formed using one or two or more materials selected from stainless steel, maraging steel, an aluminum alloy, a magnesium alloy and an amorphous alloy, for example. 
     Also, the volume of this golf club head  100  is desirably from 90 cm 3  to 460 cm 3  inclusive, for example. 
     2. Assembly Structure of Golf Club Head 
     The golf club head  100  according to the present embodiment is constituted, as shown in  FIG. 3 , by assembling a head main body  101  having a crown portion  2  and a sole portion  3  and a cup-shaped face member  102  having a face portion  1  and a peripheral portion  15  extending from the periphery of the face portion. This head main body  101  has an opening  18  enclosed by the crown portion  2  and the sole portion  3 , and the face member  102  is attached so as to close off this opening  18 . That is, an end face of the peripheral portion  15  of the face member  102  is butted against an end face of the opening  18  of the head main body  101 , and these portions are joined by welding (so-called cup face structure). The face member  102  is integrated with the head main body  101 , by being attached to an edge portion of the opening  18  of the head main body  101 , and the peripheral portion  15  of the face member  102  thereby functions as part of the crown portion  2  and the sole portion  3  of the head  100 . 
     Accordingly, the surface that is integrally formed as a result of the peripheral portion  15  of the face member  102  being attached to the head main body  101  constitutes the crown portion  2  and the sole portion  3  of the head  100 . Thus, strictly speaking, the crown portion  2  and the sole portion  3  of the head main body  101  are part of the crown portion  2  and the sole portion  3  of the head  100 , although, in this specification, these portions of the head main body  101  may also be referred to simply as the crown portion  2  and the sole portion  3 , without making this distinction. 
     3. Structure of Crown Portion 
     Next, the crown portion  2  will be described. As shown in  FIGS. 1 to 3 , the crown portion  2  is provided with a raised portion (first region)  21  that is arranged on the face portion side and a base portion (second region)  22  that is arranged further on the back side than the raised portion  21 . The raised portion  21  is mainly a band-like region extending in the toe-heel direction along the face portion  1 , with the respective end portions on the toe and heel sides extending slightly to the back side along the periphery of the crown portion  2 , and is formed as a whole to be U-shaped in plan view. On the other hand, the base portion  22  is a region that occupies most of the crown portion  2  at a lower position than the raised portion  21 , and the periphery thereof contacts the sole portion  3 . A sloped surface (step region)  23  that constitutes a step is formed on the boundary between the raised portion  21  and the base portion  22 . The height of the face portion  1  in the up-down direction is thereby increased by the amount of the step between the raised portion  21  and the base portion  22 . 
     This sloped surface  23  is configured so as to extend upward, moving toward the face portion  1  side. The sloped surface  23  can thereby be sighted from above, when the golf club head  100  is set in the reference state. That is, the sloped surface can be sighted by the golfer at address. The sloped surface  23  is formed along the raised portion  21 , and is thus formed to be U-shaped in plan view, similarly to the raised portion  21 . 
     As shown in  FIG. 3 , a width D of the raised portion  21  in the face-back direction is, in plan view, preferably set from 5 to 25 mm, and more preferably from 7 to 20 mm, for example. 
     Also, a width W of the sloped surface  23  in the face-back direction in plan view is preferably set from 3 to 9 mm, and more preferably from 3 to 7 mm, for example. Furthermore, a height H of the sloped surface  23  is preferably set from 0.5 to 8 mm, more preferably from 0.5 to 6 mm, and particularly preferably from 0.5 to 5 mm, for example. Also, an angle θ that a horizontal line passing through a base end portion of the sloped surface  23  forms with the sloped surface  23  is preferably from 30 to 60 degrees. 
     The base portion  22  curves so as to be upwardly convex. For example, the curvature radius in the cross-section shown in  FIG. 3  can be formed to be from 120 to 200 mm. The curvature radius can be formed such that when three points on the above line are prescribed, for example, the curvature radius increases approaching the front point. 
     Note that the cross-section in  FIG. 3  is a cross-section in the face-back direction passing through a face center. The face center can be defined as follows. First, an arbitrary point Po is determined generally in a vicinity of the middle of the face portion  1  (face surface) in the toe-heel direction and the up-down direction. A line x extending in the toe-heel direction is drawn through this point Po, and a midpoint Px of this line x is determined. Next, on the face portion  1 , a line y extending in the up-down direction is drawn through the point Px, and a midpoint Py of this line is determined. A process of redrawing the line extending in the toe-heel direction through the point Py determined in this way as the line x and thereafter redetermining the point Py in a similar manner to that described above is then repeatedly performed. A new point Py at which the distance between the previous point Py and the new point Py becomes 0.5 mm or less during the repetitions of this process is defined as the face center. Note that, more specifically, the above line x passing through the point Po is the line of intersection between the face surface (surface of the face portion  1 ) and a plane that contains the normal of the face surface passing through this point Po and is parallel to the toe-heel direction. Also, more specifically, the above line y passing through the point Px is the line of intersection between the face surface and a plane that contains the normal of the face surface passing through this point Px and is parallel to the up-down direction. Also, more specifically, the above line x passing through the point Py is the line of intersection between the face surface and a plane that contains the normal of the face surface passing through this point Py and is parallel to the toe-heel direction. Note that the lengths of the above lines x and y are measured along the face surface. 
     4. Structure of Inner Wall Surface of Crown Portion 
     Next, the structure of the inner wall surface of the crown portion  2  will be described. As shown in  FIGS. 2 and 3 , a rib  24  is formed on a line that passes through the above face center and extends in the face-back direction. The end portion on the face side of this rib  24  is connected to the inner wall surface of the raised portion  21  on the back side, and the end portion on the backside is connected to the inner wall surface of the end portion on the back side of the base portion  22 . That is, this rib  24  extends from the raised portion  21  to the base portion  22  via the sloped surface  23 , and extends across the entirety of the sloped surface  23  and the base portion  22  in the face-back direction. 
     The width of the rib  24  in the toe-heel direction can be set from 0.5 to 1.5 mm, for example. Also, the height of the rib  24  from the inner wall surface of the crown portion  2  can be set from 1.0 to 5.0 mm, for example. 
     The rib  24  need only be provided in a position within a range of 30 mm to the toe side and 30 mm to the heel side from the above face center, for example. 
     5. Manufacturing Method of Golf Club Head 
     Next, an example of the manufacturing method of the above golf club head will be described. First, the abovementioned head main body  101  and face member  102  are prepared. A head main body  101  and a face member  102  such as described above can be produced with various methods. For example, the head main body  101  can be manufactured by casting such as a well-known lost wax precision casting process. Also, the face member  102  can be manufactured by a method such as forging, plate pressing or casting, for example. Also, the pre-processing plate of the face member  102  that is used at this time is processed such that the rolling direction substantially coincides with the direction from an upper portion on the toe side of the face portion  1  to a lower portion on the heel side. 
     The golf club head is then completed when predetermined coating is performed after joining these portions by welding (TIG (tungsten inert gas) welding, plasma welding, laser welding, brazing, etc.), for example. 
     6. Features 
     According to the above embodiment, the following effects can be obtained. 
     (1) In the crown portion  2 , the raised portion  21  is formed higher than the base portion  22  via the sloped surface  23 , thus enabling the height of the face portion  1  to be increased by the height of the raised portion  21 . Thus, the rebound performance of the face portion  1  can be improved. Also, in the crown portion  2 , only the raised portion  21  is formed higher, and the base portion  22  occupying most of the crown portion  2  is formed at a lower position than the raised portion  21 , thus enabling the center of gravity of the head to be lowered. 
     (2) In the present embodiment, the rib  24  is provided on the inner wall surface of the crown portion  2 , but in the case where, for example, this rib is not provided, the inventor found that the crown portion  2  exhibited the following behavior when the ball hit the face portion  1 . This point will be described with reference to  FIG. 5 . 
     As shown in  FIG. 5 , when the ball hits the face portion  1 , the crown portion  2  deforms as shown by the dashed lines. First, at impact when the ball hits the face portion  1 , the crown portion  2  deforms such that the base portion  22  is pushed toward the sole portion  3  while the sloped surface  23  rises up steeply, as shown by the dashed line ( 1 ). When the ball separates from the face portion  1  in the latter part of impact, the crown portion  2  is restored from the dashed line ( 1 ), and deforms so as to bulge further upward, as shown by the dashed line ( 2 ). Following this, the crown portion  2  is restored to an initial shape, while repeatedly vibrating between the dashed lines ( 1 ) and ( 2 ). Thus, part of elastic energy stored by the deformation of the crown portion  2  in the early part of impact is converted to vibration of the crown portion  2 , and energy for rebounding the ball is lost. It was thereby found that the problem of a reduction in rebound performance arises. 
     In contrast, when the rib  24  extending in the face-back direction is provided on the inner wall surface of the crown portion  2  such as in the present embodiment, the crown portion  2  can be prevented from deforming in the manner described above. That is, the crown portion  2  is prevented from being pushed downward due to the rib  24  which extends in the face-back direction, and the crown portion  2  vibrating in the up-down direction can thereby be suppressed. As a result, a reduction in rebound performance can be prevented. In particular, this rib  24  extends across the entirety of the base portion  22 , and thus greatly contributes to suppressing the deformation of the base portion  22 . 
     (3) In the present embodiment, the respective end portions of the rib  24  are fixed to the inner wall surface of the raised portion  21  and the rear end portion of the crown portion  2 . The effect of preventing deformation of the crown portion  2  obtained by the rib  24  can be enhanced more than in the case where, for example, there are portions that do not contact the inner wall surface of the head  100  at both ends of the rib  24 , as shown in  FIG. 6 . The end portion on the face side of the rib  24  only extends partway along the raised portion  21 , however, rather than reaching the face portion  1 . Accordingly, deformation of the face portion  1  being inhibited is prevented. 
     (4) Since the crown portion  2  curves so as to be upwardly convex, pushing of the crown portion  2  toward the sole portion  3 , at the time of the impact with the ball, as shown in the above  FIG. 5 , can be suppressed. 
     7. Variations 
     Although an embodiment of the present invention is described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. Also, the following variations can be appropriately combined. Modifications such as the following can be made, for example. 
     &lt;7-1&gt; 
     In the above embodiment, the raised portion  21  and the sloped surface  23  are formed to be U-shaped in plan view, but are not limited thereto, and need only extend generally in the toe-heel direction. Accordingly, the raised portion  21  and the sloped surface  23  can also be formed in a band shape extending generally straight in the toe-heel direction, for example. Also, the sloped surface  23  may not necessarily be flat. For example, the sloped surface can also be formed to be curved. Furthermore, the region between the raised portion  21  and the base portion  22  need not necessarily be formed as a slope, and may be a step that extends in the up-down direction. 
     &lt;7-2&gt; 
     The rib  24  need only extend in the face-back direction on the inner wall surface of the crown portion  2 , and the position thereof is not particularly limited. The rib  24  need only at least extend from the sloped surface  23  across to the base portion  22 , and need not extend across the entirety of the sloped surface  23  and the base portion  22 . Also, the rib  24  need not necessarily be formed on the raised portion  21 . 
     Also, the position at which the rib  24  is provided is preferably on a line that passes through the face center and extends in the face-back direction, as described above, but is not limited thereto. For example, as shown in  FIG. 7 , a rib  24  that slopes at an angle so as to extend further on the heel side moving toward the back side from a position nearer the heel of the raised portion  21  can also be provided. In this way, the rib  24  need not strictly extend in the face-back direction, and may slope at an angle. A plurality of ribs  24  can also be formed. Also, as described above, when both end portions of the rib  24  are supported by the inner wall surface of the head, the effect of suppressing vibration obtained by the rib  24  is improved. 
     &lt;7-3&gt; 
     The head according to the above embodiment has a cup face structure, but other forms are possible. For example, the head can be constituted by fitting the crown portion  2  into an opening for the crown portion formed in a head main body that includes the face portion  1  and the sole portion  3 . Also, a cup face structure need not be adopted, and the head can be constituted by fitting a plate-like face member into an opening formed in the face portion  1  and welding the face member to the head main body. 
     &lt;7-4&gt; 
     The sole portion  3  is not particularly limited in shape, and can, from a design or structural viewpoint, be appropriately provided with recessed portions or grooves, for example. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  Face portion 
           2  Crown portion 
           21  Raised portion (first region) 
           22  Base portion (second region) 
           23  Sloped surface (step region) 
           24  Rib 
           3  Sole portion 
           4  Hosel portion