JPH02274271A - Wooden club head for golf - Google Patents

Abstract

PURPOSE:To increase head speed at the time of swing, stabilize swing orbit, and improve flying distance and directionality of ball by forming the upper and lower edge angle parts of a head body face surface into curved surfaces having a radius of curvature of 10mm or more, and forming uneven parts on the both curved surfaces to provide spiral flow generating parts. CONSTITUTION:A head body 1 is provided with respective spiral flow generating parts 20, 20' on the upper and lower edge angle parts 2a, 2b of a face surface 2. The spiral flow generating parts 20, 20' are formed by forming the upper and lower edge angle parts 2a, 2b of the face surface 2 into curved surfaces 21, 21' having radius of curvature of 10mm or more (R>10mm), and uneven parts 22, 22' consisting of a number of semi-circular recessed parts are formed on the both curved surfaces 21, 21'. Hence, peeling of an air flow boundary layer caused around a head at the time of swing can be certainly prevented, and the head speed and stability of the swing orbit can be improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a golf wood club head with an improved head shape, in which a spiral flow is formed at both upper and lower edge corners of the face surface of the head body. By providing the generating portion, it is possible to prevent laminar separation of the laminar boundary layer of the airflow flowing along the ball hitting direction on both the upper and lower surfaces of the head during swing, and to reduce air resistance force.

(2) The golf wood club head according to claim 1, wherein the uneven portion comprises a large number of hemispherical recesses.

(3) The golf wood club head according to claim 1, wherein the uneven portion is composed of a plurality of grooves having a predetermined width and depth.

(Prior Art) Generally, when a wood club swings from takeback to impact, the air flow generated around the club head has a large effect on the head speed and the stability of the swing trajectory.

Conventionally, in this type of golf wood club head, as shown in FIG. It has a unique shape in which both the surfaces (surface) 3 and lower surface (sole surface) 4 form a streamlined shape toward the back surface 5 side.

However, in a wood club head with such a conventional structure, a crown surface 3 and a sole surface 4 that are connected to the upper and lower edge corner portions 2a and 2b of the face surface 2 of the head body 1 are
Since the boundary between the head body 1 and the head body 1 is formed at an acute angle, the flow of air generated around the head body 1 (indicated by the solid arrow in FIG. 3) when the ball is swung in the hitting direction Immediately after the upper and lower edge corners 2a and 2b of the face surface 2, large turbulence occurs and laminar separation of the one-layer boundary layer occurs, and the turbulence caused by this laminar separation induces a transition from laminar flow to turbulent flow. to create a peeled area on the back surface 5 side of the head body 1,
This creates a pressure difference between the front and back of the face surface 2 of the head body 1.

By the way, in fluid mechanics, an object placed in a flow receives a force from the fluid, of which the component acting in a direction perpendicular to the mainstream is called lift force, and the component acting in a direction parallel to the mainstream is called drag force. This drag force is applied to the object, that is, the head body 1
It can be divided into pressure drag, which is obtained by integrating the pressure distribution acting on In a flow, pressure drag is large.

In particular, the pressure drag caused by the pressure difference mentioned above is 1
Due to the negative pressure effect of the separation area formed behind the separation point of the laminar boundary layer, the head speed during swing is reduced,
It is known that this not only reduces the flight distance of the ball, but also causes the swing trajectory to become unstable.

Therefore, as disclosed in Japanese Patent Publication No. 53-31417, a groove called a trip step is formed at the upper edge corner of the face surface of the head body, or as disclosed in Japanese Patent Application Publication No. 62-176469. As has been said,
There is a structure in which a large number of fine grooves are formed in a shark-skin shape over almost the entire crown surface and sole surface of the head body to generate a turbulent boundary layer on the head surface during swing.

(Problems to be Solved by the Invention) According to the wood club head according to the invention described in the above-mentioned conventional publication, by generating a turbulent boundary layer on the head surface during swing, the separation area of the boundary layer of airflow is reduced. This is designed to reduce the pressure drag by simply forming a groove called a trip step on the upper edge corner of the face surface of the head body, or by forming a groove on the crown surface and sole surface of the head body. Simply treating the surface so that many fine grooves are formed in a shark-skin pattern over almost the entire surface is not enough.
It is impossible to achieve the desired action and effect.

That is, as shown in FIG. 3, in a conventional wood club head, the boundary between the crown surface 3 and the sole surface 4, which connect the upper and lower edge corners 2a and 2b of the face surface 2 of the head body 1, has an angle. It is formed at an acute angle, and in terms of fluid dynamics,
Because the so-called ``separation area is determined congenitally,'' laminar separation of the laminar boundary layer has already occurred immediately after the upper and lower edge corners 2a and 2b of the head body face surface 2, resulting in a turbulent boundary layer. There was a problem in that it was not formed.

This invention was made under the above circumstances, and its purpose is to provide a golf golf ball that reliably prevents separation of the boundary layer of the airflow that occurs around the head during a swing. Our goal is to provide wood club heads for use.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention has a structure in which swirl flow generating portions are provided at both upper and lower edge corner portions of the face surface of the head main body. In this case, the swirling flow generating section is formed by forming both the upper and lower edge corners of the face surface of the head main body into curved surfaces with a radius of curvature of 10 mm or more, and forming uneven portions on both of these curved surfaces. be.

In addition, the uneven parts constituting the swirl flow generating part include a large number of hemispherical recesses (dimples), a plurality of grooves having a predetermined width and depth, or a plurality of grooves having a predetermined surface width and opening angle. It is preferable to form it with a V-groove.

(Function) That is, in the present invention, since the upper and lower edge corner portions of the face surface of the head body are each formed into curved surfaces with a radius of curvature of 10 mm or more, the crown surface that connects with the upper and lower edge corner portions of the face surface is formed. There is no boundary with the sole surface, and the separation point of the laminar boundary layer of the air flow generated during swing is located behind the upper and lower edge corners of the face surface, and there are irregularities on the upper and lower edge corners that form a curved surface. Because of the formation of a turbulent boundary layer, a swirling flow occurs before the separation point of the laminar boundary layer, transitioning from a single-layer flow to a turbulent flow, and a turbulent boundary layer is formed over the entire crown surface and sole surface. is formed.

As a result, the separation region of the boundary layer of the airflow is formed with a large delay in the vicinity of the back surface of the head main body, and pressure drag can be reduced.

[Embodiments] The present invention will be described below with reference to embodiments shown in FIGS. 1 and 2. In the illustrated embodiment of the present invention, parts having the same structure as those of the conventional structure shown in FIG. 3 will be described using the same reference numerals.

As shown in FIG. 1, the head body 1 of the golf wood club according to the present invention has a structure in which swirl flow generating portions 20 and 20' are provided at the upper and lower edge corner portions 2a and 2b of the face surface 2, respectively. As shown in FIG.
It is formed into a curved surface 21.21' with a diameter of 0 mm or more (R>10 mm), and an uneven portion 22.22' consisting of a large number of hemispherical concave portions is formed on each of the curved surfaces 21.21'. It is.

According to the above-described structure of the golf wood club head according to the present invention, both upper and lower edge corner portions 2a, 2b of the face surface 2 are formed into curved surfaces 21. with a radius of curvature R of 1 mm or more.
21', there is no boundary part that connects with the crown surface 3 and the sole surface 4, so the separation points A and B of the laminar boundary layer of the airflow that occurs when swinging in the hitting direction Both upper and lower edge corners 2a, 2 of surface 2
Since the curved surface 21.21' is located at the rear of the curved surface 22.22', a swirling flow is generated in front of the separation points A and B of the laminar boundary layer. A turbulent boundary layer is formed over the entire surface of the crown surface 3 and sole surface 4, and as a result, the separation region of the boundary layer of the airflow can be formed with a large delay in the vicinity of the back surface 5 of the head body 1. This allows for lower pressure drag during swing than in a conventional club head as shown in FIG.

In addition, in the above embodiment, the swirling flow generating parts 2o, 2
The concave and convex portions 22 and 22' that constitute 0'.

Although it is formed with a large number of hemispherical recesses (dimples), it may also be formed with kerfs or grooves, and in this case, the kerfs have a width of 1 to 3 mm and a depth of 0.5 mm. As mentioned above, the groove has a surface width of 1 to 3 mm,
Multiple strips with an opening angle of 60-120'', for example 1-
It is preferable to form a range of five.

[Effects of the Invention] As is clear from the above description, according to the present invention, the radius of curvature of the upper and lower edge corners of the face surface of the head body is L.
Om m or more curved surfaces are respectively formed, and the concave and convex portions are formed on both of these curved surfaces to provide a swirl flow generating section. There is no boundary with the sole surface, and the separation point of the laminar boundary layer of the air flow generated during swing can be located behind the upper and lower edge corners of the face surface, and the upper and lower edge corners form a single curved surface. Since the uneven portion is formed on the sole surface, a swirling flow can be generated in front of the separation point of the one-layer boundary layer, and a turbulent boundary layer can be formed over the entire surface of the crown surface and the sole surface.

Therefore, the separation region of the boundary layer of the airflow can be formed with a long delay near the back surface of the head body, so it is possible to reduce the pressure drag.
Since the head speed during the swing can be increased and the swing trajectory can be stabilized, the ball flight distance and directionality of the ball can be improved, which is an excellent effect.

21° 22. ３　・・ ４　・・ 5　・・ A, B X・・・ 21′...Curved surface.

22'... uneven portion, ・Top surface (crown surface), ・Bottom surface (sole surface), ・Back side, ...separation point of laminar boundary layer, ・Ball direction.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing one embodiment of a golf wood club head according to the present invention, FIG. 2 is an enlarged sectional view of a swirling flow generating part, and FIG. 3 is a diagram of a conventional golf wood club head. It is a schematic explanatory diagram.

Claims (3)

[Claims] (1) A wood club head for golf, in which both upper and lower edge corner portions of the face surface of the head main body are formed into curved surfaces with a radius of curvature of 10 mm or more, and uneven portions are formed on both of these curved surfaces. (2) The golf wood club head according to claim 1, wherein the uneven portion comprises a large number of hemispherical recesses. (3) The golf wood club head according to claim 1, wherein the uneven portion is composed of a plurality of grooves having a predetermined width and depth.