Golf club head

Abstract

To provide a golf club head advantageous in improving the durability of a face part while securing repulsion performance.SOLUTION: The face portion 14 is made of a material having a Young modulus of 30Gpa or more and 220Gpa or less, and is made of a metallic material or a fiber-reinforced plastic material. The resinous layer 32 is formed so as to cover the 14A of the face. By forming the resin layer 32, it is possible to reduce the stress generated in the face portion 14 due to energy being absorbed by the resin layer 32 when a ball is hit, which is advantageous in ensuring the durability of the face portion 14. The plastic layer 32 has a durometer hardness A85 or more and a durometer hardness D80 or less. If the hardness of the resin layer 32 falls within the above range, it is advantageous in ensuring the rebound performance of the golf club head 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a golf club head. [Background technology]

[0002] In order to control the spin rate of a hit ball within an appropriate range, a golf club head has been proposed in which a resin layer having a dynamic friction coefficient of 0.1 or more and 0.4 or less is formed on the face surface of the face portion (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-143941 Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, the resin layer formed on the face surface is thought to affect not only the amount of spin but also the repulsion performance and durability of the face portion, but these points are not particularly taken into consideration in the above-mentioned conventional technology. The present invention was made with a focus on the fact that the characteristics of the resin layer affect the durability and resilience performance of the face portion, and its purpose is to provide a golf club head that is advantageous in improving the durability of the face portion while maintaining resilience performance. [Means for solving the problem]

[0005] In order to achieve the above object, one embodiment of the present invention is a golf club head comprising a face portion made of a material having a Young's modulus of 30 GPa or more and 220 GPa or less, and a resin layer covering the face surface of the face portion, wherein the resin layer has a durometer hardness of A85 or more and a durometer hardness of D80 or less. [Effects of the Invention]

[0006] According to one embodiment of the present invention, the resin layer is formed to cover the face surface, and the resin layer absorbs energy when hitting a ball, thereby reducing stress generated in the face portion, which is advantageous in ensuring the durability of the face portion. Furthermore, the resin layer has a durometer hardness of A85 or more and a durometer hardness of D80 or less, which is advantageous in ensuring the resilience performance of the golf club head. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a front view of a golf club head according to an embodiment, viewed from the front of the face surface. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] 1A is a front view showing the shape of a type A push needle used when measuring durometer hardness A, and FIG. 1B is a front view showing the shape of a type D push needle used when measuring durometer hardness D. [Figure 4] FIG. 2 is an explanatory diagram illustrating the correspondence between durometer hardness A and durometer hardness D. [Figure 5] FIG. 10 is a diagram showing an acceleration waveform in Experimental Example 1 (Comparative Example). [Figure 6] FIG. 10 is a diagram showing an acceleration waveform in Experimental Example 2. [Figure 7] FIG. 10 is a diagram showing acceleration waveforms in Experimental Example 3. [Figure 8] FIG. 10 is a diagram showing acceleration waveforms in Experimental Example 4. [Figure 9] FIG. 10 is a diagram showing acceleration waveforms in Experimental Example 5. [Figure 10] FIG. 10 is a diagram showing acceleration waveforms in Experimental Example 6. [Figure 11] 10 is a diagram showing the relationship between the durometer hardness D for Experimental Examples 2-6 and the difference in COR relative to Experimental Example 1. FIG. [Figure 12] FIG. 10 is a diagram showing acceleration waveforms in Experimental Example 7. [Figure 13] FIG. 10 is a diagram showing an acceleration waveform in Experimental Example 8. [Figure 14] FIG. 10 is a diagram showing acceleration waveforms in Experimental Example 9. [Figure 15] FIG. 10 is a diagram showing acceleration waveforms in Experimental Example 10. [Figure 16] 10 is a diagram showing the relationship between the durometer hardness D for Experimental Examples 7-10 and the difference in COR relative to Experimental Example 1. FIG. [Figure 17] FIG. 10 is a diagram showing acceleration waveforms in Experimental Example 11. [Figure 18] FIG. 13 is a diagram showing an acceleration waveform in Experimental Example 12. [Figure 19] FIG. 13 is a diagram showing an acceleration waveform in Experimental Example 13. [Figure 20] FIG. 10 is a graph showing the relationship between the durometer hardness D for Experimental Examples 11 to 13 and the difference in COR relative to Experimental Example 1. [Figure 21] FIG. 10 is a diagram showing the evaluation results of durability in Experimental Example 1-13. [Figure 22] FIG. 10 is a diagram showing the relationship between durability (number of times) and maximum acceleration in Experimental Example 1-13. [Figure 23] FIG. 1A is a diagram showing the evaluation results of durability for each experimental example, FIG. 1B is a diagram showing the evaluation results of resilience performance for each experimental example, and FIG. 1C is a diagram showing the overall evaluation results for each experimental example. [Figure 24] FIG. 10(A) is a diagram showing the amplitude waveform of the hitting sound in Experimental Example 1 (Comparative Example), and FIG. 10(B) is a diagram showing the results of frequency analysis of FIG. [Figure 25] 10A is a diagram showing the amplitude waveform of the impact sound in Experimental Example 14 in which a resin layer was provided on the face surface of the metal face portion, and FIG. 10B is a diagram showing the results of frequency analysis of FIG. [Figure 26] 10A is a diagram showing the amplitude waveform of the hitting sound in Experimental Example 15 in which a resin layer was provided on the face surface of the FRP face portion, and FIG. 10B is a diagram showing the results of frequency analysis of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Next, an embodiment of the present invention will be described. As shown in FIGS. 1 and 2, in this embodiment, the golf club head 10 is a hollow wood-type golf club head (driver), and is configured to include a head main body 12 and a resin layer 32. The head body 12 is made of a metal material or a fiber reinforced plastic material (FRP), or is made of a combination of a metal material and a fiber reinforced plastic material. As the metal material, for example, one or more of stainless steel, maraging steel, pure titanium, titanium alloy, aluminum alloy, etc. may be used. As the fiber reinforced resin material, a carbon fiber reinforced resin material (CFRP) or the like is used. The head body 12 includes a face portion 14 , a crown portion 16 , a sole portion 18 , and a side portion 20 . The head body 12 has a hollow structure in which the inside surrounded by the face portion 14, the crown portion 16, the sole portion 18, and the side portion 20 is a hollow portion 28. The face portion 14 has a vertical height and extends laterally. In this embodiment, the face portion 14 is made of a material having a Young's modulus of 30 Gpa or more and 220 Gpa or less, and is made of the above-mentioned metal material or fiber-reinforced resin material. Using a metal material for the face portion 14 is advantageous in that the frequency of the impact sound generated when hitting the ball falls within a preferred high frequency range. Furthermore, using a fiber reinforced resin material for the face portion 14 is advantageous in reducing the weight of the golf club head 10 .

[0009] The crown portion 16 has a thickness smaller than that of the face portion 14 and extends rearward from an upper portion of the face portion 14 . The surface of the face portion 14 exposed to the outside is a face surface 14A that strikes the ball. The crown portion 16 is provided with a hosel 30 connected to the shaft S at a position on the face surface 14A side and near the heel 24, and the golf club 100 is configured by connecting the shaft S to the hosel 30. The sole portion 18 extends rearward from the lower portion of the face portion 14 . As shown in FIGS. 1 and 2, the side portion 20 extends between the crown portion 16 and the sole portion 18, between the toe 22 side edge and the heel 24 side edge of the face portion 14, passing through the back of the face.

[0010] The resin layer 32 is formed without any gaps with respect to the face surface 14A so as to cover the face surface 14A. By forming the resin layer 32 to cover the face surface 14A, the resin layer 32 absorbs energy when the ball is hit, thereby reducing the stress generated in the face portion 14, which is advantageous in ensuring the durability of the face portion 14. The resin layer 32 has a durometer hardness of not less than A85 and not more than D80. If the hardness of the resin layer 32 is within the above range, it is advantageous in ensuring the resilience performance of the golf club head 10 . If the hardness of the resin layer 32 is below the above range, the hardness of the resin layer 32 will be too low, causing excessive energy absorption by the resin layer 32, which is disadvantageous in ensuring the resilience performance of the golf club head 10. In addition, the frequency of the impact sound generated when hitting the ball will tend to be lower than the preferred high frequency range. If the hardness of the resin layer 32 exceeds the above range, the hardness of the resin layer 32 will be too high, and the energy absorbed by the resin layer 32 will be too small, which is disadvantageous in ensuring the durability of the golf club head 10 . In order to achieve the above-mentioned effects, it is more preferable that the hardness of the resin layer 32 is equal to or greater than durometer hardness A90 and equal to or less than durometer hardness D60.

[0011] Here, the durometer hardness will be explained. A durometer is a hardness tester that measures hardness by pressing a pin of a predetermined shape against the surface of a sample with the force of a spring, causing deformation, and measuring the depth to which the pin penetrates the sample when the resistance of the sample and the force of the spring are balanced. Durometer hardness A is the hardness measured using a type A push needle 50 shown in FIG. 3(A), and durometer hardness D is the hardness measured using a type D push needle 52 shown in FIG. 3(B). Generally, for samples with relatively low hardness, a type A indentation needle 50 is used for measurement, and the upper limit of the durometer hardness A is 100. On the other hand, for samples with relatively high hardness, with a durometer hardness A generally exceeding 90, a type D indentation needle 52 is used to measure the durometer hardness D. FIG. 4 is a diagram showing the correspondence between durometer hardness A and durometer hardness D, and durometer hardness A and durometer hardness D can be converted to each other using FIG.

[0012] In this embodiment, the hardness of the resin layer 32 does not refer to the hardness measured for the resin layer 32 alone, but rather refers to the hardness measured by pressing a type A push needle 50 or a type D push needle 52 into the surface of the resin layer 32 located on the opposite side of the face surface 14A when the resin layer 32 is formed on the face surface 14A. When measuring the hardness of the resin layer 32, first, the hardness is measured by durometer hardness A, and for resin layers 32 whose durometer hardness A exceeds 98, durometer hardness D is measured using a type D push needle 52.

[0013] The thickness of the resin layer 32 is not less than 0.3 mm and not more than 1.5 mm. If the thickness of the resin layer 32 is within the above range, it is advantageous for improving the durability of the face portion 14 while ensuring the repulsion performance of the golf club head 10 . If the thickness of the resin layer 32 is below the above range, the resin layer 32 is too thin and the energy at the time of hitting the ball is not sufficiently absorbed by the resin layer 32, so the effect of the resin layer 32 in alleviating the stress in the face portion 14 is reduced, and the effect of ensuring the durability of the golf club head 10 is reduced. If the hardness of the resin layer 32 exceeds the above range, the resin layer 32 becomes too thick and absorbs too much energy at the time of hitting the ball, thereby reducing the effect of ensuring the resilience performance of the golf club head 10. Additionally, the frequency of the impact sound generated when the ball is hit tends to be lower than the high frequency range (roughly around 4000 Hz) that golfers find pleasant when listening to impact sounds. It is more preferable that the thickness of the resin layer 32 be 0.3 mm or more and 0.5 mm or less in order to achieve the above-mentioned effects.

[0014] As the material for forming the resin layer 32, polyurethane, ionomer resin, or ultra-high molecular weight polyethylene is preferable because of its excellent processability. The material of the resin layer 32 is not limited as long as the hardness of the resin layer 32 is within the above-mentioned range.

[0015] The resin layer 32 is provided on the face 14A by painting, coating, bonding, adhesion, welding, or bonding using an anchor effect. Note that bonding using the anchor effect refers to bonding of the resin layer 32 to the face surface 14A by the molten resin layer 32 penetrating into the minute unevenness formed on the face surface 14A and solidifying.

[0016] Furthermore, as shown in FIG. 2, it is preferable that the thickness of a central portion 3202 of the resin layer 32 corresponding to the central portion of the face surface 14A is greater than the thickness of a peripheral portion 3204 of the resin layer 32 corresponding to the peripheral portion of the face surface 14A, and that the thickness of the resin layer 32 gradually decreases from the central portion 3202 to the peripheral portion 3204. This is because higher durability is required for the central portion 3202 of the resin layer 32, which corresponds to the area with a high impact point distribution, in other words, the central portion of the face surface 14A where the ball is hit frequently, while not as high durability is required for the peripheral portion 3204 of the resin layer 32, which corresponds to the area with a low impact point distribution, in other words, the peripheral portion of the face surface 14A where the ball is hit less frequently. In other words, the central portion of the face portion 14 deforms more when hitting the ball than the peripheral portion of the face portion 14, which is disadvantageous in terms of ensuring durability, and therefore it is necessary to ensure greater durability in the central portion of the face portion 14. Setting the thickness of the resin layer 32 in this manner is advantageous in ensuring the durability of the golf club head 10 while reducing its weight.

[0017] Furthermore, the golf club head 10 of this embodiment preferably has a coefficient of restitution (COR) of 0.822 or more. That is, in a golf club head 10 having a restitution coefficient of 0.822 or more, which is called a high-restitution head, the thickness of the face portion 14 is reduced in order to ensure the amount of deflection of the face portion 14 when hitting the ball, which tends to reduce the durability of the face portion 14. Therefore, forming the resin layer 32 on the face surface 14A is advantageous in ensuring the durability of a golf club head 10 having a restitution coefficient of 0.822 or more.

[0018] Next, the experimental results of the golf club head 10 will be described. In the following, a sample golf club head 10 was produced for each experimental example, and the repulsion performance and durability were evaluated under the following conditions.

[0019] Experimental Example 1 is a comparative example, and is a golf club head 10 in which the resin layer 32 is not provided on the face surface 14A, and does not satisfy the provisions of claim 1 of the present invention. The specifications of each part in Experimental Example 1 are as follows: Material of head body 12: Titanium alloy Ti-8Al-1Mo-1V Material of face portion 14: Ti-6Al-4V Loft angle 10.5° Lie angle 59° Head volume 460cc

[0020] The following experimental examples, except for experimental example 1 (comparative example), have the same specifications as experimental example 1, except that a resin layer 32 is provided. In addition, in each of the following experimental examples except for experimental example 1 (comparison example), the thickness of the resin layer 32 is uniform, and therefore the thickness of the central portion 3202 of the resin layer 32 and the thickness of the peripheral portion 3204 of the resin layer 32 are also uniform.

[0021] In the following, a pendulum testing machine was used for the golf club head 10 of each experimental example, and the shaft was attached to the golf club head 10 and fixed with a jig, and a certain impact force was applied to the face portion 14 with the pendulum, and the acceleration (acceleration waveform) was measured with an acceleration sensor attached to the pendulum. The measurement results of the acceleration waveform are shown in Figures 5 to 10, where the horizontal axis is time (μs) and the vertical axis is acceleration (m / s 2 ) are shown. In the figure, the values ​​in μs units on the left side indicate the CT value calculated from the acceleration waveform, and the values ​​in m / s units on the right side indicate the CT value calculated from the acceleration waveform. 2 The unit value indicates the maximum acceleration (peak value of acceleration).

[0022] (Condition 1) Changing the hardness of the resin layer 32 Under condition 1, the thickness of the resin layer 32 was set to 1.0 mm in each of Experimental Examples 2 to 6, and only the hardness of the resin layer 32 was changed. FIG. 5: Experimental Example 1 (Comparative Example) No resin layer 32 Figure 6: Experimental Example 2: Durometer hardness D90 Figure 7: Experimental Example 3: Durometer hardness D80 Figure 8: Experimental Example 4: Durometer hardness A98 Figure 9: Experimental Example 5: Durometer hardness A85 Figure 10: Experimental Example 6: Durometer hardness A70

[0023] As can be seen by comparing Figure 5 with Figures 6 to 10, in Experimental Examples 2 to 6 in which resin layer 32 was provided, compared to Experimental Example 1, the maximum acceleration was lower because energy was absorbed by the deformation of resin layer 32 when the ball was hit.In addition, it was found that the high-frequency components of the acceleration waveform, in other words, the vibrations that resonate in the hands, were absorbed by resin layer 32, resulting in a softer and improved hitting feel felt by the golfer. Furthermore, as can be seen from Figures 6 to 10, the lower the hardness of the resin layer 32, the more easily the resin layer 32 deforms and absorbs energy when hitting the ball, resulting in a decrease in maximum acceleration while increasing the CT value (the time the ball is in contact with the face surface 14A via the resin layer 32).

[0024] In FIG. 11, the horizontal axis shows Durometer D hardness, and the vertical axis shows the decrease in COR of each experimental example relative to the COR of experimental example 1 (i.e., the difference obtained by subtracting the COR of the experimental example from the COR of experimental example 1), and the values ​​of experimental examples 2 to 6 are plotted. The values ​​of the durometer A hardness were converted to values ​​of the durometer D hardness using FIG. FIG. 11 shows that the resilience performance of Experimental Example 6 (Durometer hardness A70), which generally has a durometer D hardness of less than 35 (durometer hardness A of less than 85), drops sharply compared to the resilience performance of the other Experimental Examples 2-5. Therefore, it is clear that in order to ensure resilience performance, the hardness of the resin layer 32 needs to be equal to or greater than durometer hardness A85.

[0025] (Condition 2) The thickness of the resin layer 32 is changed. In condition 2, the hardness of the resin layer 32 was kept constant at durometer hardness A85, and only the thickness of the resin layer 32 was changed, and the same acceleration waveform as in condition 1 was measured. FIG. 12: Experimental Example 7: Resin layer 32 thickness: 0.3 mm FIG. 13: Experimental Example 8: Resin layer 32 thickness: 0.5 mm FIG. 14: Experimental Example 9: Resin layer 32 thickness: 1.0 mm FIG. 15: Experimental Example 10: Resin layer 32 thickness: 2.0 mm The resin layer 32 in Experimental Examples 7-10 was made of polyurethane (PU).

[0026] As can be seen from Figures 12 to 15, the thicker the resin layer 32, the more easily the resin layer 32 deforms when hitting the ball, resulting in a decrease in maximum acceleration while increasing the CT value (the time the ball is in contact with the face surface 14A via the resin layer 32).

[0027] In FIG. 16, the horizontal axis represents the thickness of the resin layer 32, and the vertical axis represents the amount of decrease in COR in each experimental example relative to the COR in experimental example 1, with the values ​​for experimental examples 7 to 10 being plotted. Looking at Figure 16, it can be seen that when the hardness of the resin layer 32 is low, at durometer hardness A85, the resilience performance of Experimental Example 10 (thickness 2.0 mm), which has a thickness of over 1.5 mm, drops sharply compared to the resilience performance of the other Experimental Examples 7-9. Therefore, in order to ensure resilience performance, it is advantageous for the resin layer 32 to be as thin as possible, and it can be said that it is advantageous for the thickness to be approximately 1.5 mm or less.

[0028] (Condition 3) The thickness of the resin layer 32 is changed. In condition 3, the hardness of the resin layer 32 was kept constant at durometer hardness D80, and only the thickness of the resin layer 32 was changed, and the same acceleration waveform as in condition 1 was measured. FIG. 17: Experimental Example 11: Resin layer 32 thickness: 0.5 mm FIG. 18: Experimental Example 12: Resin layer 32 thickness: 1.0 mm FIG. 19: Experimental Example 13: Resin layer 32 thickness: 2.0 mm The resin layer 32 in Experimental Examples 17-19 was made of polycarbonate (PC).

[0029] As can be seen from Figures 17 to 19, the thicker the resin layer 32, the more easily the resin layer 32 deforms when hit with a ball, resulting in a decrease in maximum acceleration and a longer CT value (the time the ball is in contact with the resin layer 32).

[0030] In FIG. 20, the horizontal axis represents the thickness of the resin layer 32, and the vertical axis represents the decrease in COR for each experimental example relative to the COR for experimental example 1, with the values ​​for experimental examples 11 to 13 plotted. In FIG. 20, an experimental example in which the resin layer 32 has a thickness of 1.5 mm is added, and the drawing of the acceleration waveform for this experimental example is omitted. Looking at Figure 20, it can be seen that when the hardness of the resin layer 32 is high, at durometer hardness D80, the resilience performance of Experimental Example 13 (thickness 2.0 mm) with a thickness of 2.0 mm decreases, although not as rapidly, compared to the resilience performance of the other Experimental Examples 11 and 12 and the Experimental Examples with a resin layer 32 thickness of 1.5 mm. Therefore, in order to ensure resilience performance, it is advantageous for the resin layer 32 to be as thin as possible, and it can be said that it is advantageous for the thickness to be at least 1.5 mm or less.

[0031] (Condition 4) Durability Condition 4 evaluated the durability of the above-mentioned Experimental Examples 1-13. Durability was evaluated by repeatedly hitting golf balls with an air cannon against the face surface 14A (resin layer 32) of the golf club head 10 fixed to the shaft, and measuring the number of hits required until deformation, cracking, or damage occurred in the face portion 14 including the resin layer 32. As shown in Figure 21, the durability was evaluated on a three-level scale (×: poor durability, △: no problem with durability, ○: good durability) depending on the number of hits. The ball speed was set to 50 m / s, and the impact point was set to the geometric center of the face 14A.

[0032] FIG. 22 is a diagram plotting experimental examples 1-13, with the horizontal axis representing the number of hits and the vertical axis representing the maximum acceleration, and the ranges of the above three-level evaluation criteria are entered. The lower the maximum acceleration of the golf club head 10, the more durable it is, and the higher the maximum acceleration, the more durable it is. This is because the hardness of the resin layer 32 is low, and the thicker the resin layer 32, the lower the maximum acceleration, and the energy generated when hitting the ball is absorbed by the resin layer 32, thereby reducing the stress generated in the face portion 14. In other words, the harder the resin layer 32 is and the thinner the resin layer 32 is, the higher the maximum acceleration becomes, and the less energy generated when hitting the ball is absorbed by the resin layer 32, resulting in higher stress generated in the face portion 14.

[0033] Figure 23 shows an evaluation of durability (Figure 23(A)), resilience performance (Figure 23(B)), and overall performance (Figure 23(C)) for several experimental examples (including the aforementioned experimental examples 2-13) in which the hardness and thickness of the resin layer 32 were varied, each evaluated on a three-point scale (x: poor evaluation, △: acceptable evaluation, ○: good evaluation). The overall evaluation in Figure 23(C) is a combination of the two evaluations in Figures 23(A) and (B), and the evaluation is determined as follows: If the two ratings are × and ×, the overall rating is ×. If the two ratings are × and △, the overall rating is ×. If the two ratings are △ and △, the overall rating is △. If the two ratings are △ and ○, the overall rating is △. If the two ratings are OK and NO, the overall rating is NO. If the two ratings are ○ and ○, the overall rating is ○. As shown in Figure 23(C), when the hardness of the resin layer 32 is in the range of Durometer A hardness 85 or more and Durometer D hardness 80 or less, and the thickness of the resin layer 32 is in the range of 0.3 mm or more and 1.5 mm or less, the overall evaluation is △ or ○.

[0034] (Condition 5) Condition 5 evaluated the sound pressure and frequency distribution of the sound (hitting sound) when a ball was hit at the center point (face center) of the face surface 14A using a swing robot. Figures 24 to 26 show the measurement results for Experimental Examples 1, 14, and 15, respectively. (A) shows the sound wave signal with time on the horizontal axis and amplitude on the vertical axis, and (B) shows the frequency analysis results with frequency on the horizontal axis and sound pressure on the vertical axis. In Experimental Example 1 (comparative example) of FIG. 24, as described above, the resin layer 32 is not formed on the face surface 14A. In Experimental Example 14 of FIG. 25, the head main body 12 (face portion 14) is made of a titanium alloy, and a resin layer 32 is formed on the face surface 14A. In Experimental Example 15 of FIG. 26, the head main body 12 (face portion 14) is made of CFRP, and a resin layer 32 is formed on the face surface 14A. In Experimental Examples 14 and 15, the hardness of the resin layer 32 was set to durometer A90, and the thickness of the resin layer 32 was set to 0.5 mm.

[0035] As is clear from FIGS. 24 to 26, in Experimental Example 1, the impact sound is loudest and there is a clear peak in the frequency band where golfers feel comfortable when listening to the impact sound. Furthermore, in Experimental Example 14, although the volume of the impact sound is lower than in Experimental Example 1, there is a clear peak in the frequency band that golfers find comfortable when listening to the impact sound. Furthermore, in Experimental Example 15, the impact sound is even quieter than in Experimental Example 14, and there is no clear peak in the frequency band that golfers find comfortable when listening to the impact sound. Therefore, in terms of the evaluation of hitting sounds, Experimental Example 14 in which the head body 12 (face portion 14) is made of metal is more advantageous than Experimental Example 15 in which the head body 12 (face portion 14) is made of CFRP.

[0036] In this embodiment, the golf club head 10 is described as a hollow wood-type golf club head (driver), but the present invention is of course also applicable to golf club heads that do not have a hollow portion, such as hollow utilities, fairway woods, or cavity irons. [Explanation of symbols]

[0037] 10. Golf club head 12 Head body 14 Face 14A Face 16 Crown part 18 Sole 20 Side part 22 Tou 24 Heels 28 Hollow part 30 Hosel 32 Resin layer 3202 Central part 3204 Peripheral part 50 Type A push pins 52 Type D push pin 100 golf clubs S shaft

Claims

1. a face portion made of a material having a Young's modulus of 30 GPa or more and 220 GPa or less; a resin layer covering a face surface of the face portion, The resin layer has a durometer hardness of A85 or more and a durometer hardness of D80 or less. A golf club head characterized by:

2. The thickness of the resin layer is 0.3 mm or more and 1.5 mm or less.

2. The golf club head according to claim 1.

3. The resin layer is formed of polyurethane, ionomer resin, or ultra-high molecular weight polyethylene.

2. The golf club head according to claim 1.

4. The resin layer is provided on the face surface by any one of painting, coating, adhesion, pressure-sensitive adhesion, welding, and bonding by an anchor effect.

2. The golf club head according to claim 1.

5. The material of the face portion is fiber reinforced resin.

2. The golf club head according to claim 1.

6. The material of the face portion is a metal material.

2. The golf club head according to claim 1.

7. a thickness of a central portion of the resin layer corresponding to a central portion of the face surface is greater than a thickness of a peripheral portion of the resin layer corresponding to a peripheral portion of the face surface, and the thickness of the resin layer is gradually reduced from the central portion to the peripheral portion.

2. The golf club head according to claim 1.

8. The coefficient of restitution is 0.822 or more.

2. The golf club head according to claim 1.

Images