JP2018202036A - Golf club - Google Patents

Abstract

To provide a golf club used in ground golf or park golf, in which a face base as an inner layer hardly breaks even in play in a cold environment such as in winter.SOLUTION: A golf club 100 comprises a head 101. The head 101 has a face 102 on the head 101 across a face base 110. The face base 110 comprises a resin material harder than the face 120 with a degree of hardness increasing as the temperature decreases. The face 120 is constructed by forming an elastomeric material into a plate shape, characterized in that it has elasticity allowing elastic deformation upon striking a ball and in that the amount of reduction in the loss coefficient tanδ associated with a temperature drop in the temperature range from 0°C to 35°C is less than the amount of reduction associated with the temperature drop in the temperature range from 0°C to 35°C in the loss coefficient tanδ of the face base 110.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a golf club used for ground golf or park golf.

  Conventionally, various golf clubs used for ground golf or park golf have been proposed. For example, Patent Document 1 below discloses a golf club in which a face member that forms a head for hitting a ball and that directly contacts the ball is formed of two layers, an inner layer and an outer layer. In this case, the face member is formed of a viscoelastic body that easily elastically deforms the outer layer in direct contact with the ball, and the head body is damaged by providing an inner layer made of a resin material harder than the outer layer on the back side of the outer layer. To prevent it.

Japanese Patent Laid-Open No. 2006-230685

  However, in the golf club described in Patent Document 1 described above, the temperature dependency of the resin material constituting each of the inner layer and the outer layer is generally higher than that of a metal material or the like, and becomes harder and more brittle as the temperature becomes lower. Therefore, there is a problem that the inner layer made of a harder resin material is easily damaged by impact when hitting a ball when playing in a low temperature environment such as winter.

  The present invention has been made to address the above problems, and an object of the present invention is to provide a golf club for use in ground golf or park golf in which the face base as an inner layer is not easily damaged even when played in a low temperature environment such as winter. There is.

  In order to achieve the above object, a feature of the present invention is a golf club used for ground golf or park golf in which a shaft that extends in a rod shape is provided on a head for hitting a ball, the head comprising: a head body to which the shaft is attached; The face comprises a face that is supported by the head body and elastically deforms when the ball is hit, and a face base that is made of a material harder than the face and is provided between the head body and the face, In the face, the amount of decrease in the loss coefficient tan δ accompanying the temperature decrease in the temperature range of 0 ° C. to 35 ° C. is the amount of decrease in the face base loss coefficient tan δ due to the temperature decrease in the temperature range of 0 ° C. to 35 ° C. Less than that.

  According to the characteristics of the present invention configured as described above, the golf club hit the ball at a low temperature because the amount of decrease in the face loss coefficient tan δ accompanying the temperature decrease is lower than the amount of decrease in the face base loss coefficient tan δ. It is possible to prevent the face base from being damaged by suppressing a reduction in the impact absorption rate by the face and mitigating the impact transmitted to the face base cured at a low temperature. In this case, the reduction amount of each loss coefficient tan δ of the face and the face base can be replaced with a decrease rate of each loss coefficient tan δ accompanying a temperature decrease within a temperature range of 0 ° C. to 35 ° C. In addition, according to the golf club of the present invention, it is possible to suppress changes in controllability and flight distance when a ball is hit between a high temperature environment such as summer and a low temperature environment such as winter. be able to. In addition, the golf club can also relieve the impact transmitted to the user by absorbing the impact of the face even when the face base changes to hard at low temperatures and the repulsive force due to the impact of the ball increases. .

  Here, the loss coefficient tan δ is a ratio between the storage elastic modulus and the loss elastic modulus. The storage elastic modulus indicates the rigidity of the viscoelastic body during dynamic behavior. Moreover, the loss elastic modulus indicates the disappearance energy of viscoelasticity during dynamic behavior.

  Another feature of the present invention is that in the golf club, the face base has a loss coefficient tan δ of 0.05 or more.

  According to another aspect of the present invention configured as described above, the golf club has a face base loss coefficient tan δ of 0.05 or more, and the face base is configured to more easily absorb vibration. The face base absorbs the impact when hitting the ball more effectively and the repulsive force is suppressed to improve the controllability of the ball, making it easier for younger, beginners or seniors to play. . On the other hand, if the face-based loss coefficient tan δ is less than 0.05, the controllability of the ball is lowered, but the rebound of the ball is improved, so it can be said that it is suitable for intermediate and advanced players. Further, in the golf club according to the present invention, the impact absorption rate when the ball is hit can be improved, so that damage to the face base can be more effectively suppressed even at low temperatures such as in winter. .

  Another feature of the present invention is that in a golf club, the difference between the face loss coefficient tan δ and the face base loss coefficient tan δ increases as the temperature decreases.

  According to another aspect of the present invention configured as described above, the golf club is configured such that the difference between the loss coefficient tan δ increases as the temperature decreases between the face and the face base. For example, damage to the face base can be more effectively prevented in an environment of 10 ° C. or less.

  Another feature of the present invention is that in the golf club, the face has a maximum loss coefficient tan δ in a temperature range of 0 ° C. to 35 ° C.

  According to another feature of the present invention thus configured, the golf club has a maximum value in the temperature range of 0 ° C. to 35 ° C. of the face loss coefficient tan δ. The impact absorption at the time of hitting can be maximized, and since the increase / decrease amount of the loss factor tanδ with respect to the temperature change near this maximum value is small, the controllability of the ball and the change in the flight distance when the ball is hit can be suppressed. . Note that the maximum value of the loss coefficient tan δ is whether or not there is a maximum value in the temperature range of 0 ° C. to 35 ° C., and is independent of the presence or absence of the maximum value outside this temperature range.

1 is an overall perspective view schematically showing the overall configuration of a golf club according to an embodiment of the present invention. FIG. 2 is an essential part enlarged perspective view schematically showing an overall configuration of a head in the golf club shown in FIG. 1. FIG. 3 is a cross-sectional view of an essential part schematically showing the internal configuration of the head shown in FIG. 2. 3 is a characteristic graph showing each loss coefficient tan δ in the temperature range of 0 ° C. to 35 ° C. of the face base and the face shown in FIG. FIG. 3 is a perspective view schematically showing an overall configuration of a face base in the head shown in FIG. 2. FIG. 3 is a perspective view schematically showing an overall configuration of a face in the head shown in FIG. 2.

  Hereinafter, an embodiment of a golf club according to the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an outline of the overall configuration of a golf club 100 according to the present invention. 2 is a partially enlarged perspective view of the head 101, which is a main part of the golf club 100 shown in FIG. 1, viewed from another direction. FIG. 3 is a cross-sectional view schematically showing the internal structure of the head 101 shown in FIG. Note that each drawing referred to in the present specification is schematically represented by exaggerating some of the components in order to facilitate understanding of the present invention. For this reason, the dimension, ratio, etc. between each component may differ. This golf club 100 is a rod-like tool for hitting a ball in ground golf or park golf.

(Configuration of golf club 100)
The golf club 100 mainly includes a head 101 and a shaft 106. The head 101 is a portion for hitting a resin ball (not shown) used in ground golf or park golf in the golf club 100, and mainly includes a head body 102, a face base 110, and a face 120. ing.

  The head body 102 is a component that supports the face base 110 and the face 120, and is configured by forming a rigid body (for example, wood) into a block shape. An attachment front surface 103 is formed on a part of the outer surface of the head main body 102 so as to extend in a smooth flat shape in the vertical direction. The face base 110 and the face 120 are attached to the attachment front surface 103, respectively. Yes. In this case, the attachment front surface 103 is formed with fitting holes 104 into which the main body fitting portions 124 are fitted at positions corresponding to the two main body fitting portions 124 in the face 120.

  The outer peripheral portion of the mounting front surface 103 is formed in a shape corresponding to the outer peripheral portion of the face base 110, and the outer peripheral portion of the mounting front surface 103 and the outer peripheral portion of the face base 110 are formed flush with each other. The head main body 102 is provided with a sole 105 on the lower surface and a shaft 106 on the upper surface.

  The sole 105 is a component for protecting the lower surface of the head main body 102, and is configured by forming an aluminum material into a shape that curves along the bottom surface of the head main body 102. In this case, the sole 105 is formed to a size that covers the bottom surface of the face base 110 as well as the bottom surface of the head body 102. The sole 105 is attached to the bottom surface of the head body 102 with a screw (not shown). The sole 105 can be formed in a shape that covers only the bottom surface of the head body 102 and does not cover the bottom surface of the face base 110.

  The shaft 106 is a component that supports the head 101 in a swingable manner, and is configured by forming a wood or carbon material into a rod shape. The shaft 106 has a head main body 102 attached to one end (lower end in the figure) and a grip 107 attached to the other end (upper end in the figure). The grip 107 is a portion that a user playing golf grips with his / her hand, and is formed by forming a rubber material into a cylindrical shape. The grip 107 is inserted into the other end of the shaft 106.

  The face base 110 is a component that covers the back surface 122 and the outer periphery 123 of the face 120, and is configured by forming a material harder than the face 120 into a plate shape. In this case, the material constituting the face base 110 includes a resin material, metal material, or wood that is harder than the face 120. In this case, the resin material includes an elastomer material harder than the face 120 in addition to a hard resin material. More specifically, the resin material preferably has a durometer hardness (temperature 23 ° C. ± 2 ° C., humidity 50% ± 5%) of HDD 60-100. In the present embodiment, the face base 110 is made of a thermoplastic polyurethane resin.

  Further, the face base 110 has a characteristic that the hardness increases and becomes hard as the temperature decreases in a temperature range of at least 0 ° C. to 35 ° C. Here, the hardness is one of the mechanical properties of the material of the face base 100 or near the surface, is the difficulty of deformation of the object by an external force, and is also referred to as “hardness”.

  That is, as shown in FIG. 4, the face base 110 has a loss factor tan δ of 0.05 or more in the temperature range of 0 ° C. to 35 ° C., and the loss factor (also referred to as “loss tangent”) tan δ as the temperature decreases. Has a characteristic of decreasing. Here, the significance of defining the temperature range of 0 ° C. to 35 ° C. is the temperature range of the face base 110, but corresponds to the temperature environment for playing ground golf and park golf. Therefore, if play at less than 10 ° C. or 30 ° C. or higher is not assumed, the temperature range defining the loss coefficient tan δ may be 10 ° C. or higher and 25 ° C. or lower.

  Further, the loss coefficient tan δ is a ratio between the storage elastic modulus and the loss elastic modulus in a viscoelastic body such as an elastomer material. A larger value means that the response is delayed and the vibration suppressing effect is higher. The storage elastic modulus indicates the rigidity of the viscoelastic body during dynamic behavior. Moreover, the loss elastic modulus indicates the disappearance energy of viscoelasticity during dynamic behavior. In FIG. 4, each loss coefficient tan δ of the face base 110 and the face 120 is indicated by a solid line in the range of −12.5 ° C. to 37.5 ° C., and each outside thereof is indicated by a broken line.

  As shown in FIG. 5, the face base 110 mainly includes a cover part 111 and a back base part 112. The cover portion 111 is a portion that covers the outer peripheral portion 123 of the face 120, and is formed in an annular shape that surrounds the outer peripheral portion 123 of the face 120. In this case, the cover 111 is formed such that the inner peripheral portion thereof has a shape corresponding to the outer peripheral portion 123 of the face 120 and the outer peripheral portion extends linearly or curvedly along the forming direction of the inner peripheral portion. ing.

  The back base portion 112 is a portion that is formed in a plate shape on the inner side of the annular cover portion 111 and to which the face 120 is attached while the cover portion 111 is integrated and reinforced in the inner direction, and is integrated with the cover portion 111. Is formed. Thus, the face base 110 is formed as a region for holding the face 120 in a concave region surrounded by the cover portion 111 and the back base portion 112.

  Through holes 113 are formed in the back base portion 112 at positions corresponding to the body fitting portions 124 in the face 120. Further, the thickness of the back base portion 112 is the same as the thickness of the face 120. Of course, the thickness of the back base 112 may be equal to or less than the thickness of the face 120.

  The face 120 is a component that strikes in direct contact with a ball, and is formed by forming an elastomer material into a plate shape. In this case, the elastomer material constituting the face 120 is a rubber material or a resin material having elasticity that elastically deforms when a ball is hit, and more specifically, a thermosetting elastomer material (for example, vulcanized rubber). , Urethane rubber, silicone rubber, fluorine rubber, etc.) and thermoplastic elastomer materials (for example, styrene-based, olefin-based, vinyl chloride-based, urethane-based or amide-based resins). In the present embodiment, the face 120 is made of a thermoplastic polyurethane resin. Further, the hardness of the face 120 is preferably durometer hardness (temperature 23 ° C. ± 2 ° C., humidity 50% ± 5%) and HDA 70-100.

  Further, as shown in FIG. 4, the face 120 has a loss coefficient tan δ of 0.05 or more and a value larger than the loss coefficient tan δ in the face base 110 in the temperature range of 0 ° C. to 35 ° C. It has a characteristic of once rising and then decreasing. In this case, the loss coefficient tan δ in the face 120 is decreased by a temperature decrease in the temperature range of 0 ° C. to 35 ° C. The temperature decrease in the temperature range of 0 ° C. to 35 ° C. in the loss coefficient tan δ of the face base 110. It has characteristics that are less than the amount of decrease associated with.

  In this embodiment, the loss coefficient tan δ of the face 120 is about 0.17 at about 35 ° C., 0.2 at about 20 ° C., and about 0.17 at 0 ° C. The amount of decrease in the loss factor tan δ accompanying the temperature decrease within the temperature range of ° C. is about 0.03. On the other hand, the loss coefficient tan δ of the face base 110 is about 0.15 at about 35 ° C., 0.09 at about 20 ° C., and about 0.06 at 0 ° C., so that the temperature of 0 ° C. to 35 ° C. The amount of decrease in loss factor tan δ accompanying the temperature decrease within the range is about 0.09.

  As shown in FIG. 6, the face 120 has a surface 121 for hitting a ball formed in a smooth flat shape, and a back surface 122 which is the back side of the surface 121 is 2 on both sides in the left and right direction on the smooth plane. Two main body fitting portions 124 are respectively formed. Further, the outer peripheral portion 123 of the face 120 is formed in a shape corresponding to the inner peripheral surface of the cover portion 111 of the face base 110 and is covered with the cover portion 111.

  In the present embodiment, the face 120 has a height that is the width in the vertical direction when hitting the ball is equal to or less than the diameter (6 cm) of the ball, and a horizontal width direction that is orthogonal to the height direction is equal to or greater than the diameter (6 cm) of the ball. Are formed in a horizontally long plate shape (preferably twice the diameter of the ball). Note that the size and shape of the face 120 is not limited to the present embodiment as long as it is formed in a size and shape capable of hitting a ball.

  The main body fitting portion 124 is a portion for attaching the face 120 to the head main body 102, and is formed to protrude from the back surface 122 of the face 120 in a column shape. The main body fitting portions 124 are formed at the center in the vertical direction on the back surface 122 of the face 120 and at both ends in the width direction. Of course, one or three or more main body fitting portions 124 may be provided. The face 120 is covered with the surface 121 exposed in the face base 110.

(Manufacture of golf club 100)
Here, the manufacturing process of the golf club 100 will be briefly described. First, the worker manufactures the face base 110 as the first step. Specifically, the operator performs injection molding of the face base 110 using an injection molding machine (not shown).

  Next, the worker manufactures the face 120 as the second step. Specifically, the operator performs injection molding of the face 120 using an injection molding machine in a state where the face base 110 is placed in a mold (not shown) for molding the face 120. That is, the front surface 121, the back surface 122, and the main body fitting portion 124 of the face 120 are integrally formed with respect to the face base 110 by insert molding processing in which the face base 110 is disposed in the mold. The face 120 can also be manufactured by forming the face 120 alone and then fitting it into the face base 110 without insert molding the face base 110.

  Next, the operator prepares the head main body 102 as the third step. Specifically, the worker forms necessary shapes such as the outer shape, the mounting front surface 103, and the fitting hole 104 by cutting the wood.

  Next, the worker attaches the face 120 and the face base 110 to the head main body 102 as a fourth step. Specifically, the operator applies an adhesive to the back surface of the face base 110 to which the face 120 is integrally attached, and affixes it to the attachment front surface 103 of the head body 102. In this case, the two main body fitting portions 124 of the face 120 are fitted into the fitting holes 104 of the mounting front surface 103 of the head main body 102, respectively.

  Next, the operator prepares the sole 105 and attaches it to the head body 102 as a fifth step. Specifically, the worker attaches a sole 105 separately manufactured using a processing method such as aluminum die casting to the lower surface of the head main body 102 using screws (not shown).

  Next, as a sixth step, the worker grinds the outer peripheral surface of the face base 110 together with the side surface of the head main body 102. Thereby, the step between the outer peripheral surface of the mounting front surface 103 of the head main body 102 and the outer peripheral surface of the face base 110 is eliminated, and both are flush with each other. In this case, since the face base 110 is made of a material harder than the face 120, the grinding process can be performed with high accuracy. In addition, it is not necessary to perform the grinding process in the sixth step when the step does not occur or when the step is acceptable.

  Next, the worker paints the outer surface of the head body 102 as a seventh step. Specifically, the worker colors the outer surface of the head body 102 by spraying or the like in a state where the face 120 and the face base 110 in the head body 102 are masked.

  Next, the operator prepares the shaft 106 and attaches it to the head body 102 as an eighth step. Specifically, the operator inserts and attaches a shaft 106 separately manufactured by cutting and painting to wood onto the upper surface of the head main body 102. Next, the operator inserts and attaches the grip 107 manufactured in a separate process to the upper end portion of the shaft 106. Needless to say, the grip 107 may be attached in advance to the shaft 106 before being inserted into the head main body 102. Thereafter, the operator completes the golf club 100 through an inspection process for testing the appearance and feeling of use.

(Operation of the golf club 100)
Next, the operation of the golf club 100 configured as described above will be described. A user playing golf hits the ball with the face 120 by holding the grip 107 and swinging the head 101. In this case, the face 120 and the face base 110 repel the ball with a loss coefficient tan δ at a temperature corresponding to a temperature environment such as air temperature or solar radiation used.

  In this case, the loss coefficient tan δ of the face 120 and the face base 110 becomes lower as the playing temperature becomes lower. That is, the face 120 and the face base 110 have higher hardness and lower toughness as the temperature is lowered, and the storage elastic modulus increases and / or the loss elastic modulus decreases. As a result, the face base 110 is originally made of a material harder than the face 120. However, the face base 110 is more easily damaged by the impact of the ball than the face 120 due to curing at a low temperature.

  However, in the face 120, the amount of decrease in the loss coefficient tan δ accompanying the temperature decrease in the temperature range of 0 ° C. to 35 ° C. is the temperature decrease in the temperature range of 0 ° C. to 35 ° C. in the loss coefficient tan δ of the face base 110. It has characteristics that are less than the accompanying reduction. In other words, since the face 120 is configured to be less elastic than the face base 110 with respect to a temperature drop, a reduction in impact absorption capability due to a ball hit is suppressed. Thereby, the face base 110 is prevented from being damaged by the face 120 being partially absorbed by the face 120 even during play at low temperatures. Further, the golf club 100 relieves the impact transmitted to the user by absorbing the impact of the face 120 even when the face base 110 changes to hard at low temperatures and the repulsive force due to the ball hitting becomes large. be able to.

  As can be understood from the above description of the operation, according to the above embodiment, the golf club 100 has a reduction amount of the loss coefficient tan δ of the face 120 that is lower than a reduction amount of the loss coefficient tan δ of the face base 110 due to a temperature drop. Further, it is possible to prevent the face base 110 from being damaged by suppressing the reduction of the impact absorption rate by the face 120 when the ball is hit at a low temperature and reducing the impact transmitted to the face base 110 cured by the low temperature. In addition, according to the golf club 100 of the present invention, the controllability and the flight distance of the ball when hit in a high temperature environment such as summer and when the ball is hit in a low temperature environment such as winter are changed. Can be suppressed.

  Furthermore, in carrying out the present invention, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the object of the present invention.

  For example, in the above-described embodiment, the face 120 is defined such that the amount of decrease in the loss coefficient tan δ of the face 120 due to the temperature decrease is lower than the amount of decrease in the loss coefficient tan δ of the face base 110. However, the face 120 can be expected to have the same function and effect even if the reduction rate of the loss coefficient tan δ of the face 120 due to the temperature drop is specified to be lower than the reduction rate of the loss coefficient tan δ of the face base 110.

  Further, in the above-described embodiment, the face 120 is configured such that the loss coefficient tan δ becomes a maximum value in a temperature range of 0 ° C. to 35 ° C., specifically, about 20 ° C. As a result, the golf club 100 can maximize the absorption of impact at the time of hitting the ball near the maximum value, and the increase / decrease amount of the loss coefficient tanδ with respect to the temperature change near the maximum value is small. The change in the controllability and flight distance of the ball can be suppressed. However, the face 120 does not necessarily have the maximum value in the temperature range of 0 ° C. to 35 ° C., and the face 120 may be configured such that the loss factor tan δ only increases or decreases with a temperature change.

  Further, in the above-described embodiment, the face 120 and the face base 110 are configured such that the difference in the loss coefficient tan δ increases as the temperature decreases. As a result, the golf club 100 can prevent the face base 110 from being damaged by mitigating the transmission of the impact to the face base 110 when the ball is hit even in a lower temperature environment (for example, 10 ° C. or less). . However, the golf club 100 may be configured such that the difference between the loss coefficients tan δ decreases as the temperature of the face 120 and the face base 110 decreases, or the difference between the two decreases with temperature decrease.

  In the above embodiment, the face base 110 has a loss coefficient tan δ of 0.05 or more. Thereby, the golf club 100 can easily absorb the impact when the face 120 hits the ball even at low temperatures such as in winter, and can prevent the face base from being damaged. However, the face base 110 can be configured with a loss coefficient tan δ of less than 0.05. According to this, the golf club 100 can improve the repulsive force when hitting the ball. Even when the loss coefficient tan δ of the face base 110 is 0.05 or more or 0.05 or less, the loss coefficient tan δ of the face 120 is preferably 0.05 or more, but is configured to be less than 0.05. This is not excluded.

  Further, in the above-described embodiment, the face 120 and the face base 110 are made of a resin material whose loss coefficient tan δ has the characteristics shown in FIG. However, the face base 110 only needs to be made of a material that is harder than the face 120 and that increases in hardness as the temperature decreases. Further, in the face 120, the amount of decrease in the loss coefficient tan δ accompanying the temperature decrease in the temperature range of 0 ° C. to 35 ° C. is the temperature decrease in the temperature range of 0 ° C. to 35 ° C. in the loss coefficient tan δ of the face base 110. What is necessary is just to be comprised with less material than the accompanying fall amount. That is, the face 120 and the face base 110 do not need to be made of materials having loss characteristics tanδ that are exactly the same as those shown in FIG.

  In the above embodiment, the face base 110 includes the cover portion 111 that covers the outer peripheral portion 123 of the face 120. However, the face base 110 can be configured by only the back base portion 112 without the cover portion 111.

  In the above embodiment, the face 120 is made of a material that is elastically deformed when a ball is hit. However, the face 120 only needs to be made of a softer material than the face base 110, and can be made of, for example, a hard resin material (for example, HDA 100 or more).

  In the above embodiment, the face 120 is formed such that the center in the vertical direction and the center in the width direction are recessed in the front view. However, the shape of the face 120 is not particularly limited, and can be formed into a rectangular shape such as a rectangle or a square, a polygon such as a pentagon or a hexagon, or a circle such as a circle or an ellipse. .

  In the above embodiment, the face 120 includes the main body fitting portion 124. However, the face 120 may be configured by omitting the main body fitting portion 124 and attached to the face base 110 or the head main body 102 using an adhesive.

DESCRIPTION OF SYMBOLS 100 ... Golf club, 101 ... Head, 102 ... Head main body, 103 ... Mounting front surface, 104 ... Fitting hole, 105 ... Sole, 106 ... Shaft, 107 ... Grip,
110 ... Face base, 111 ... Cover part, 112 ... Back base part, 113 ... Through hole,
120 ... face, 121 ... front surface, 122 ... back surface, 123 ... outer peripheral portion, 124 ... main body fitting portion.

In order to achieve the above object, a feature of the present invention is a golf club used for ground golf or park golf in which a shaft that extends in a rod shape is provided on a head for hitting a ball, the head comprising: a head body to which the shaft is attached; A face made of an elastomer material that forms a striking surface that is elastically deformed when hitting a ball supported by the head body, and a face that is made of an elastomer material harder than the face and is provided between the head body and the face And the face has a temperature drop within the temperature range of 0 ° C. to 35 ° C. in the loss coefficient tan δ of the face base when the loss factor tan δ decreases with a temperature drop in the temperature range of 0 ° C. to 35 ° C. It is less than the amount of reduction accompanying the reduction.

Claims (4)

A golf club used for ground golf or park golf in which a shaft extending in a rod shape is provided on a head for hitting a ball,
The head is
A head body to which the shaft is attached;
A face constituting a striking surface which is supported by the head body and elastically deforms when the ball is hit;
A face base made of a material harder than the face and provided between the head body and the face,
The face is
The amount of decrease in the loss factor tan δ accompanying the temperature decrease in the temperature range of 0 ° C. to 35 ° C. is less than the amount of decrease in the loss coefficient tan δ of the face base due to the temperature decrease in the temperature range of 0 ° C. to 35 ° C. A golf club characterized by having less. The golf club according to claim 1,
The face base is
The golf club characterized in that the loss coefficient tan δ is 0.05 or more. In the golf club according to claim 1 or 2,
The golf club according to claim 1, wherein a difference between the loss coefficient tan δ of the face and the loss coefficient tan δ of the face base increases as the temperature decreases. In the golf club according to any one of claims 1 to 3,
The face is
A golf club characterized in that the loss coefficient tan δ has a maximum value in a temperature range of 0 ° C to 35 ° C.

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