Golf Club Shafts

Abstract

To provide a golf club shaft which gives excellent feeling to an athlete type golfer in spite of the light weight.SOLUTION: A shaft 6 is 50 g or less. Flex by fixing a grip side is 110 mm or less, and flex by fixing a head side is 100 mm or less. Shaft torque is 4.0° to 6.5°. The shaft 6 includes a first hoop layer f1, a second hoop layer f2 longer than the first hoop layer f1, and a third hoop layer f3 longer than the second hoop layer f2. When an outer diameter at a position of 550 mm from a tip end Tp is D5, an outer diameter at a position of 950 mm from the tip end Tp is D9, crushing strength at a position of 550 mm from the tip end Tp is F5, and crushing strength at a position of 950 mm from the tip end Tp is F9, F5 / D5 is 1.5 or more and 2.5 or less, and F9 / D9 is 1.0 or more and 2.0 or less. A difference (F5-F9) is 4 kgf of less.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to golf club shafts. [Background technology]

[0002] A lightweight shaft is advantageous for improving the flight distance. However, the reduction in weight can reduce the bending rigidity. JP 2014-171582 A describes a shaft that is lightweight while maintaining bending rigidity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-171582 A Summary of the Invention [Problem to be solved by the invention]

[0004] Golfers who are relatively physically strong and competitive are also called athletic golfers. From the viewpoint of feeling, many athletic golfers have been unable to use a lightweight shaft. If athletic golfers can use a lightweight shaft, it is effective in improving the flying distance. In addition, for athletic golfers whose muscles have decreased due to aging or the like, if they can use a lightweight shaft, they can recover the flying distance.

[0005] An example of the present disclosure provides a golf club shaft that is lightweight yet provides a good feeling for athletic golfers. [Means for solving the problem]

[0006] In one embodiment, the golf club shaft is formed of a plurality of fiber reinforced resin layers and has a tip end and a butt end. The shaft weight is 50 g or less. The forward flex is 110 mm or less. The reverse flex is 100 mm or less. The shaft torque is 4.0° or more and 6.5° or less. The plurality of fiber reinforced resin layers include a first hoop layer disposed from the butt end to a first position, a second hoop layer disposed from the butt end to a second position and longer than the first hoop layer, and a third hoop layer disposed from the butt end to a third position and longer than the second hoop layer. The outer diameter of the shaft at a position 550 mm from the tip end is D5 (mm), the outer diameter of the shaft at a position 950 mm from the tip end is D9 (mm), the crushing strength at a position 550 mm from the tip end is F5 (kgf), and the crushing strength at a position 950 mm from the tip end is F9 (kgf). F5 / D5 is 1.5 or more and 2.5 or less. F9 / D9 is 1.0 or more and 2.0 or less. The difference (F5-F9) is 4 kgf or less. Effect of the Invention

[0007] As one aspect, a golf club shaft that is lightweight yet provides a good feeling for athletic golfers can be provided. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an overall view of a golf club equipped with a golf club shaft according to an embodiment. [Diagram 2] FIG. 2 is a development view of the golf club shaft of FIG. [Diagram 3] FIG. 3(a) is a schematic diagram showing a method for measuring forward flex, and FIG. 3(b) is a schematic diagram showing a method for measuring reverse flex. [Figure 4] FIG. 4 is a schematic diagram showing a method for measuring the shaft torque. [Diagram 5] FIG. 5 is a schematic diagram showing a method for measuring the impact absorption energy. [Figure 6]FIG. 6 is a graph showing an example of a waveform obtained when measuring impact absorption energy. [Figure 7] FIG. 7 is a schematic diagram showing a method for measuring the crushing strength. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the drawings as appropriate.

[0010] In this application, the terms "layer" and "sheet" are used. A "layer" is the name after it has been rolled, whereas a "sheet" is the name before it has been rolled. A "layer" is formed by rolling a "sheet." In other words, the rolled "sheet" forms a "layer."

[0011] In this application, the same reference numerals are used for layers and sheets, for example, the layer formed by sheet s1 is referred to as layer s1.

[0012] In this application, the axial direction means the axial direction of the shaft. In this application, the circumferential direction means the circumferential direction of the shaft. Unless otherwise specified, the length in this application means the length in the axial direction. Unless otherwise specified, the position in this application means the position in the axial direction. Unless otherwise specified, the "inner" in this application means the inner side in the radial direction of the shaft. Unless otherwise specified, the "outer" in this application means the outer side in the radial direction of the shaft.

[0013] FIG. 1 shows a golf club 2 equipped with a golf club shaft 6 according to the present disclosure. The golf club 2 includes a head 4, a shaft 6, and a grip 8. The head 4 is provided at a tip portion of the shaft 6. The grip 8 is provided at a butt portion of the shaft 6. The shaft 6 is a shaft for a wooden club. The golf club 2 is a driver (No. 1 wood). The shaft 6 is a shaft for a driver.

[0014] The head 4 and the grip 8 are not limited. Examples of the head 4 include a wood type head, a utility type head, an iron type head, and a putter head. In this embodiment, the head 4 is a wood type head. In this embodiment, the head 4 is a driver head.

[0015] The shaft 6 is formed of a plurality of fiber reinforced resin layers. The type of fiber is not limited. In this embodiment, a carbon fiber reinforced resin layer and a glass fiber reinforced resin layer are used as the fiber reinforced resin layer. The shaft 6 is a tubular body. Although not shown, the shaft 6 has a hollow structure. The shaft 6 has a tip end Tp and a butt end Bt. In the golf club 2, the tip end Tp is located inside the head 4. In the golf club 2, the butt end Bt is located inside the grip 8.

[0016] The shaft 6 has a tapered portion in which the outer diameter continuously increases toward the butt end Bt. At least an area of ​​the shaft 6 that is 200 mm or more and 950 mm or less away from the tip end Tp is the tapered portion.

[0017] 1, what is indicated by the double-headed arrow Ls is the length of the shaft 6. This distance Ls is measured along the axial direction.

[0018] The shaft 6 is formed by winding a plurality of prepreg sheets. In these prepreg sheets, the fibers are substantially oriented in one direction. A prepreg in which the fibers are substantially oriented in one direction is also called a UD prepreg. "UD" is an abbreviation for unidirectional. Note that a prepreg other than a UD prepreg may be used. For example, the fibers may be woven in the prepreg sheet. In the present application, the prepreg sheet is also simply called a sheet.

[0019] The prepreg sheet includes fibers and a resin. The resin is also called a matrix resin. Examples of the fibers include carbon fibers and glass fibers. Typically, the matrix resin is a thermosetting resin.

[0020] Examples of the matrix resin of the prepreg sheet include thermosetting resins and thermoplastic resins. From the viewpoint of shaft strength, the matrix resin is preferably a thermosetting resin, and more preferably an epoxy resin.

[0021] The shaft 6 is manufactured by a sheet winding method. In the prepreg, the matrix resin is in a semi-cured state. In the shaft 6, a prepreg sheet is wound and cured. This curing means that the matrix resin in the semi-cured state is cured. This curing is achieved by heating. The manufacturing process of the shaft 6 includes a heating step. This heating cures the matrix resin of the prepreg sheet.

[0022] FIG. 2 is a development of a prepreg sheet constituting the shaft 6. FIG. 2 shows the sheets constituting the shaft 6. The shaft 6 is composed of a plurality of sheets. As shown in FIG. 2, the shaft 6 is composed of 16 sheets. The shaft 6 has a first sheet s1 to a sixteenth sheet s16. This development shows the sheets constituting the shaft in order from the radially inner side of the shaft 6. The sheets are wound in order from the sheet located at the top in FIG. 2. In FIG. 2, the left-right direction of the drawing coincides with the axial direction. In FIG. 2, the right side of the drawing is the tip side of the shaft. In FIG. 2, the left side of the drawing is the butt side of the shaft.

[0023] Fig. 2 shows not only the winding order but also the arrangement in the axial direction. For example, in Fig. 2, one end of the sheet s1 is located at the tip end Tp.

[0024] The shaft 6 has a straight layer, a bias layer, and a hoop layer.

[0025] The orientation angle of the fibers of each sheet is shown in Figure 2. The sheet marked with "0°" is a straight sheet. The straight sheet constitutes a straight layer.

[0026] The straight layer is a layer in which the fiber orientation is substantially 0° with respect to the axial direction. Due to errors during winding, etc., the fiber orientation may not usually be completely parallel to the shaft axis direction. In the straight layer, the absolute angle of the fibers with respect to the shaft axis is 10° or less. The absolute angle is the absolute value of the angle (fiber angle) between the shaft axis and the fiber direction. In other words, an absolute angle of 10° or less means that the fiber angle is between -10 degrees or more and +10 degrees or less.

[0027] 2, the sheets constituting the straight layer (straight sheets) are sheet s1, sheet s2, sheet s6, sheet s8, sheet s9, sheet s10, sheet s11, sheet s13, sheet s14, sheet s15, and sheet s16. The straight layer greatly contributes to bending rigidity and bending strength.

[0028] The bias layer is a layer in which the fiber orientation is substantially inclined with respect to the axial direction. The bias layer has a large contribution to the torsional rigidity and torsional strength. Preferably, the bias layer is formed of two sheet pairs in which the fiber orientation is inclined in opposite directions. Preferably, the sheet pair includes a layer with a fiber angle of -60° or more and -30° or less, and a layer with a fiber angle of 30° or more and 60° or less. That is, preferably, the bias layer has an absolute angle of 30° or more and 60° or less.

[0029] In the shaft 6, the sheets (bias sheets) constituting the bias layer are sheets s3 and s4. The sheets s3 and s4 form a sheet pair. The sheets s3 and s4 are laminated together and wound in this sheet pair state.

[0030] In FIG. 2, the fiber angle is shown for each sheet. The plus (+) and minus (-) in the fiber angle indicate the inclination direction of the fibers. In a sheet pair, a sheet with a positive fiber angle is combined with a sheet with a negative fiber angle. In each sheet pair, the fibers are inclined in opposite directions. Note that in FIG. 2, the fiber orientation direction is the same for sheets s3 and s4, but because sheet s4 is turned over and attached to sheet s3, the fiber directions are opposite to each other.

[0031] The hoop layer is a layer in which the fibers are arranged substantially along the circumferential direction of the shaft. Preferably, in the hoop layer, the absolute angle of the fibers is substantially 90° with respect to the shaft axis. However, due to errors in winding, the orientation of the fibers may not be completely 90° with respect to the shaft axis. Usually, in this hoop layer, the absolute angle of the fibers is 80° or more and 90° or less.

[0032] The hoop layer contributes greatly to the crushing rigidity and crushing strength of the shaft. Crushing rigidity is rigidity against crushing deformation. Crushing deformation is deformation caused by a force that crushes the shaft radially inward. In a typical crushing deformation, the cross section of the shaft changes from circular to elliptical. Crushing strength is strength against crushing deformation. Crushing strength can also be related to bending strength. Crushing deformation can occur in conjunction with bending deformation. This correlation is particularly large in lightweight shafts with thin walls. Improving crushing strength can contribute to improving bending strength.

[0033] In the embodiment of FIG. 2, the prepreg sheets (hoop sheets) for the hoop layer are sheet s5, sheet s7 and sheet s12.

[0034] A combined sheet is used to manufacture the shaft 6 shown in Fig. 2. The combined sheet is formed by laminating a plurality of sheets together.

[0035] In the embodiment of FIG. 2, four sets of combined sheets are used. The first combined sheet is a combination of sheets s3 and s4. The second combined sheet is a combination of sheets s5 and s6. The third combined sheet is a combination of sheets s7 and s8. The fourth combined sheet is a combination of sheets s12 and s13.

[0036] As described above, in this application, sheets and layers are classified according to the orientation angle of the fibers, and in addition, in this application, sheets and layers are classified according to the length in the axial direction.

[0037] A layer disposed over the entire axial direction is referred to as a full-length layer. A sheet disposed over the entire axial direction is referred to as a full-length sheet. A rolled full-length sheet forms a full-length layer. On the other hand, a layer disposed partially in the axial direction is referred to as a partial layer. A sheet disposed partially in the axial direction is referred to as a partial sheet. A rolled partial sheet forms a partial layer.

[0038] A full length layer that is a bias layer is called a full length bias layer. A full length layer that is a straight layer is called a full length straight layer. A full length layer that is a hoop layer is called a full length hoop layer.

[0039] In the embodiment of Fig. 2, the sheets constituting the full length bias layer are sheet s3 and sheet s4. The sheets constituting the full length straight layer are sheet s10, sheet s13 and sheet s14. The shaft 6 has a plurality of full length straight layers s10, s13 and s14. The sheet constituting the full length hoop layer is sheet s12.

[0040] A partial layer that is a bias layer is referred to as a partial bias layer. A partial layer that is a straight layer is referred to as a partial straight layer. A partial layer that is a hoop layer is referred to as a partial hoop layer.

[0041] In the embodiment of Fig. 2, no partial bias layer is provided. The sheets constituting the partial straight layer are sheet s1, sheet s2, sheet s9, sheet s11, sheet s15, and sheet s16. The sheets constituting the partial hoop layer are sheet s5 and sheet s7. There is no partial hoop layer other than layer s5 and layer s7.

[0042] Sheets s1, s2, s9, s11, s15 and s16 constitute a tip partial straight layer. The tip partial straight layer is disposed at the tip portion of the shaft 6. One end of the tip partial straight layer is located at the tip end Tp.

[0043] The sheets s6 and s8 configure a butt partial straight layer. The butt partial straight layer is disposed at the butt end of the shaft 6. One end of the butt partial straight layer is located at the butt end Bt.

[0044] The sheets s5 and s7 are butt partial hoop layers. The butt partial hoop layer is disposed at the butt end of the shaft 6. One end of the butt partial hoop layer is located at the butt end Bt.

[0045] The manufacturing process of this shaft 6 will be outlined below.

[0046] [Outline of shaft manufacturing process]

[0047] (1) Cutting process In the cutting process, the prepreg sheet is cut into a desired shape. Through this process, each sheet shown in FIG. 2 is cut out.

[0048] The cutting may be performed by a cutting machine or manually, for example, by using a utility knife.

[0049] (2) Bonding process In this step, a plurality of sheets are laminated together to produce the above-mentioned combined sheet. Heating and / or pressing may be used in the lamination step.

[0050] (3) Winding process In the winding process, a mandrel is prepared. Typically, the mandrel is made of metal. A release agent is applied to the mandrel. A tacky resin is then applied to the mandrel. The resin is also called a tacking resin. The cut sheet is then wound around the mandrel. The tacking resin facilitates attachment of the sheet end to the mandrel.

[0051] This winding step results in a wound body. In this wound body, the prepreg sheet is wound around the outside of the mandrel. This winding is performed, for example, by rolling the object to be wound on a flat surface. This winding may be performed manually or by a machine. This machine is called a rolling machine.

[0052] (4) Tape wrapping process In the tape wrapping process, a tape is wrapped around the outer circumferential surface of the wound body. This tape is also called wrapping tape. This wrapping tape is wound in a spiral shape without gaps while being tensioned. This wrapping tape applies pressure to the wound body. This pressure contributes to reducing voids.

[0053] (5)Curing process In the curing process, the wound body after the tape wrapping is heated. This heating causes the matrix resin to harden. During this curing process, the matrix resin temporarily becomes fluid. This fluidization of the matrix resin can cause air to be expelled between or within the sheets. The clamping force of the wrapping tape promotes the expulsion of this air. As a result of this curing, a hardened laminate is obtained.

[0054] (6) Mandrel removal process and wrapping tape removal process After the curing step, the mandrel is removed and the wrapping tape is removed. Preferably, the mandrel is removed and the wrapping tape is removed.

[0055] (7) Both ends cutting process In this step, both ends of the cured laminate are cut to make the end faces of the tip end Tp and the butt end Bt flat.

[0056] (8) Polishing process In this process, the surface of the cured laminate is polished. The wrapping tape leaves spiral-shaped irregularities on the surface of the cured laminate. Polishing removes these irregularities and makes the surface smooth.

[0057] (9) Painting process After the sanding step, the cured laminate is painted.

[0058] The forward flex and reverse flex are measured for the shaft 6. The forward flex and reverse flex are specifications relating to the bending stiffness of the shaft 6.

[0059] FIG. 3(a) shows a method for measuring forward flex. As shown in FIG. 3(a), a first support point S1 is set at a position 1093 mm from the tip end Tp. Furthermore, a second support point S2 is set at a position 953 mm from the tip end Tp. A support B1 that supports the shaft 6 from above is provided at the first support point S1. A support B2 that supports the shaft 6 from below is provided at the second support point S2. In a no-load state, the shaft axis of the shaft 6 is horizontal. A load of 2.7 kgf is applied vertically downward to a load point k1 that is 129 mm away from the tip end Tp. The distance (mm) of the load point k1 between the no-load state and the stable state with the load applied is the forward flex. This distance is measured along the vertical direction.

[0060] The cross-sectional shape of the part of the support B1 that abuts against the shaft (hereinafter referred to as the abutment part) is as follows: In a cross section parallel to the shaft axial direction, the cross-sectional shape of the abutment part of the support B1 has a convex round shape. The radius of curvature of this round shape is 15 mm. In a cross section perpendicular to the shaft axial direction, the cross-sectional shape of the abutment part of the support B1 has a concave round shape. The radius of curvature of this concave round shape is 40 mm. In a cross section perpendicular to the shaft axial direction, the horizontal length (depth direction length in FIG. 3(a)) of the abutment part of the support B1 is 15 mm. The cross-sectional shape of the abutment part of the support B2 is the same as that of the support B1. The cross-sectional shape of the abutment part of the load indenter (not shown) that applies a load of 2.7 kgf at the load point k1 has a convex round shape in a cross section parallel to the shaft axial direction. The radius of curvature of this round shape is 10 mm. The cross-sectional shape of the contact portion of the load indenter (not shown) that applies a load of 2.7 kgf at the load point k1 is a straight line in a cross section perpendicular to the shaft axial direction. The length of this straight line is 18 mm. A weight including this load indenter is hung from the load point k1.

[0061] Fig. 3(b) shows the method for measuring the reverse flex. The reverse flex is measured in the same manner as the forward flex, except that the first support point S1 is set 12 mm away from the tip end Tp, the second support point S2 is set 152 mm away from the tip end Tp, the load point k2 is set 924 mm away from the tip end Tp, and the load is set to 1.3 kgf.

[0062] The shaft torque is measured for the shaft 6. The shaft torque is the torsional angle when a predetermined torque is applied to the shaft 6. Therefore, the smaller the shaft torque, the higher the torsional rigidity of the shaft 6.

[0063] 4 is a schematic diagram showing a method for measuring the shaft torque. The portion from a point 40 mm from the tip end Tp to the tip end Tp is fixed by a jig M1. This fixing is achieved by an air chuck, and the air pressure of this air chuck is 2.0 kgf / cm 2The jig M2 is fixed to a portion 50 mm wide on the butt end Bt side from a position 825 mm away from the jig M1. This fixing is achieved by an air chuck, and the air pressure of this air chuck is 1.5 kgf / cm 2 With jig M1 fixed, jig M2 is rotated to apply a torque of 0.139 kgf m to shaft 6. The twisting angle (°) caused by this torque is the shaft torque. The smaller the shaft torque, the higher the torsional rigidity of shaft 6.

[0064] The three-point bending strength of the shaft 6 is measured. This strength can be measured by the SG-type three-point bending strength test. This test is a test for golf club shafts established by the Japan Product Safety Association (CPSA number 0098). In this test, the strength is measured at points T, A, B, and C. Point T is located 90 mm from the tip end Tp. Point A is located 175 mm from the tip end Tp. Point B is located 525 mm from the tip end Tp. Point C is located 175 mm from the butt end Bt.

[0065] The impact absorption energy of the tip of the shaft 6 is measured. This indicates the strength against the impact when hitting.

[0066] FIG. 5 shows a method for measuring the impact absorption energy of the tip. In this measurement, the tip of the shaft cut at a position 200 mm from the tip end Tp is used. This measurement is an impact test using a cantilever bending method. A drop weight impact tester (IITM-18) manufactured by Yonekura Seisakusho is used as the measuring device 20. The tip of the shaft from the tip end Tp to 50 mm is fixed to a fixing jig 22. A 600 g weight W is collided at a position 100 mm from the fixed end, that is, at a position 150 mm from the tip end Tp. The weight W is dropped from 1500 mm above the shaft 6 to collide. An accelerometer 24 is attached to the weight W. The accelerometer 24 is connected to an FFT analyzer 28 via an AD converter 26. A measurement waveform is obtained by FFT processing. Through this measurement, the displacement D and the impact bending load L are measured, and the impact absorption energy until the start of destruction is calculated.

[0067] Fig. 6 is an example of a measured waveform. This waveform is a graph showing the relationship between the displacement D (mm) and the impact bending load L (kgf). In the graph of Fig. 6, the area of ​​the hatched portion is the impact absorption energy Em (J).

[0068] The crushing strength of the shaft 6 is measured. FIG. 7 shows the method of this measurement. A universal testing machine (220X type) manufactured by INTESCO is used for the measurement. A sliced ​​sample 30 having an axial width of 10 mm is cut out from the shaft 6 with the measurement position as the center. The sample is placed on a receiving jig 32 whose upper surface 32a is a horizontal plane, and the sample 30 is compressed by an indenter jig 34. The indenter jig 34 is lowered vertically downward to compress the sample 30, and the load at the time of complete destruction is measured. The sample 30 is compressed so as to cause a crushing deformation. The lower surface 34a of the indenter jig 34, which is the surface that presses the sample, is a plane parallel to the upper surface 32a of the receiving jig 32. The speed at which the indenter jig 34 is lowered is 5 mm / min.

[0069] The shaft 6 is lightweight, yet provides a good feeling and is easy to swing for athletic golfers. Therefore, the shaft 6 can be used by athletic golfers who have avoided lightweight shafts. By using a lightweight shaft, athletic golfers who are relatively physically strong can greatly improve their head speed. The athletic golfers referred to in this application are golfers who have a driver head speed of about 40 to 48 m / s.

[0070] The shaft 6 is lightweight. By making the shaft lighter, the head speed increases. From this viewpoint, the shaft weight is preferably 50g or less, more preferably 49g or less, and more preferably 48g or less. From the viewpoint of strength, the shaft weight is preferably 30g or more, more preferably 32g or more, and more preferably 34g or more. The shaft weight of Example 1 described later was 47g.

[0071] From the viewpoint of providing a comfortable feel for athletic golfers, the forward flex is preferably 110 mm or less, more preferably 108 mm or less, and even more preferably 106 mm or less. From the viewpoint of increasing head speed by flex return, the forward flex is preferably 80 mm or more, more preferably 85 mm or more, and even more preferably 90 mm or more. The forward flex of Example 1 described later was 105 mm.

[0072] From the viewpoint of providing a comfortable feeling for athletic golfers, the reverse flex is preferably 100 mm or less, more preferably 98 mm or less, and even more preferably 96 mm or less. From the viewpoint of increasing head speed by flex return, the reverse flex is preferably 70 mm or more, more preferably 75 mm or more, and even more preferably 80 mm or more. The reverse flex of Example 1 described later was 95 mm.

[0073] The rebound is a phenomenon in which the shaft returns to its original position, causing the head to lag behind in the direction of the swing. The rebound during the downswing increases head speed.

[0074] From the viewpoint of providing a comfortable feel for athletic golfers, the shaft torque is preferably 6.5° or less, more preferably 6.4° or less, and more preferably 6.3° or less. In a lightweight shaft, the amount of material used is limited. From this viewpoint, the shaft torque is preferably 4.0° or more, more preferably 4.1° or more, and more preferably 4.2° or more. The shaft torque in Example 1 described below was 6.2°.

[0075] Shafts used by athletic golfers require high strength. From this viewpoint, the three-point bending strength at point T (90 mm from tip end Tp) is preferably 190 kgf or more, more preferably 195 kgf or more, and more preferably 200 kgf or more. In a lightweight shaft, the amount of material used is limited. From this viewpoint, the three-point bending strength at point T is preferably 220 kgf or less, more preferably 215 kgf or less, and more preferably 210 kgf or less.

[0076] Shafts used by athletic golfers require high strength. From this viewpoint, the three-point bending strength at point A (175 mm from the tip end Tp) is preferably 70 kgf or more, more preferably 73 kgf or more, and more preferably 75 kgf or more. In a lightweight shaft, the amount of material used is limited. From this viewpoint, the three-point bending strength at point A is preferably 85 kgf or less, more preferably 83 kgf or less, and more preferably 80 kgf or less.

[0077] Shafts used by athletic golfers require high strength. From this viewpoint, the three-point bending strength at point B (525 mm from the tip end Tp) is preferably 65 kgf or more, more preferably 68 kgf or more, and more preferably 70 kgf or more. In a lightweight shaft, the amount of material used is limited. From this viewpoint, the three-point bending strength at point B is preferably 80 kgf or less, more preferably 78 kgf or less, and more preferably 75 kgf or less.

[0078] Shafts used by athletic golfers require high strength. From this viewpoint, the three-point bending strength at point C (175 mm from the butt end Bt) is preferably 90 kgf or more, more preferably 95 kgf or more, and more preferably 100 kgf or more. In a lightweight shaft, the amount of material used is limited. From this viewpoint, the three-point bending strength at point C is preferably 120 kgf or less, more preferably 115 kgf or less, and more preferably 110 kgf or less.

[0079] When an athletic golfer hits the ball, a strong impact is applied to the tip of the shaft. From this viewpoint, the impact absorption energy of the tip is preferably 3.4 J or more, more preferably 3.5 J or more, and more preferably 3.6 J or more. In a lightweight shaft, the amount of material used is limited. From this viewpoint, the impact absorption energy of the tip is preferably 4.0 J or less, more preferably 3.9 J or less, and more preferably 3.8 J or less.

[0080] From the viewpoint of firmness and strength, the crushing strength at a position 550 mm from the tip end Tp is preferably 11 kgf or more, more preferably 17 kgf or more, and more preferably 18 kgf or more. In a lightweight shaft, the amount of material used is limited. From this viewpoint, the crushing strength at a position 550 mm from the tip end Tp is preferably 26 kgf or less, more preferably 25 kgf or less, and more preferably 24 kgf or less.

[0081] From the viewpoint of firmness and strength, the crushing strength at a position 650 mm from the tip end Tp is preferably 11 kgf or more, more preferably 16 kgf or more, and more preferably 17 kgf or more. In a lightweight shaft, the amount of material used is limited. From this viewpoint, the crushing strength at a position 650 mm from the tip end Tp is preferably 24 kgf or less, more preferably 23 kgf or less, and more preferably 22 kgf or less.

[0082] From the viewpoint of firmness and strength, the crushing strength at a position 750 mm from the tip end Tp is preferably 11 kgf or more, more preferably 15 kgf or more, and more preferably 16 kgf or more. In a lightweight shaft, the amount of material used is limited. From this viewpoint, the crushing strength at a position 750 mm from the tip end Tp is preferably 22 kgf or less, more preferably 21 kgf or less, and more preferably 20 kgf or less.

[0083] From the viewpoint of firmness and strength, the crushing strength at a position 850 mm from the tip end Tp is preferably 11 kgf or more, more preferably 14 kgf or more, and more preferably 15 kgf or more. In a lightweight shaft, the amount of material used is limited. From this viewpoint, the crushing strength at a position 850 mm from the tip end Tp is preferably 20 kgf or less, more preferably 19 kgf or less, and more preferably 18 kgf or less.

[0084] From the viewpoint of firmness and strength, the crushing strength at a position 950 mm from the tip end Tp is preferably 11 kgf or more, more preferably 13 kgf or more, and more preferably 14 kgf or more. In a lightweight shaft, the amount of material used is limited. From this viewpoint, the crushing strength at a position 950 mm from the tip end Tp is preferably 19 kgf or less, more preferably 18 kgf or less, and more preferably 17 kgf or less.

[0085] 2, the shaft 6 includes a first hoop layer f1 arranged from the butt end Bt to a first position P1, a second hoop layer f2 arranged from the butt end Bt to a second position P2 and longer than the first hoop layer f1, and a third hoop layer f3 arranged from the butt end Bt to a third position P3 and longer than the second hoop layer f2. The second position P2 is located closer to the tip side than the first position P1. The third position P3 is located closer to the tip side than the second position P2. In this embodiment, the first hoop layer f1 is layer s5, the second hoop layer f2 is layer s7, and the third hoop layer f3 is layer s12.

[0086] In this embodiment, the third position P3 is the tip end Tp, and the third hoop layer f3 is a full-length hoop layer. The third hoop layer f3 may be a partial hoop layer. When the third hoop layer f3 is a partial hoop layer, the length of the third hoop layer f3 is preferably 900 mm or more, more preferably 950 mm or more, even more preferably 1000 mm or more, and is preferably 1150 mm or less, even more preferably 1140 mm or less, even more preferably 1130 mm or less. The first hoop layer f1 and the second hoop layer f2 are butt partial hoop layers.

[0087] It was found that the three hoop layers f1, f2, and f3 of different lengths are effective for athletic golfers. It was found that athletic golfers find it easier to swing a shaft with a firm grip. In a lightweight shaft with a thin wall thickness, the part with a large outer diameter is easily crushed. The three hoop layers f1, f2, and f3 of different lengths reinforce the crushing rigidity of the butt side, which has a larger outer diameter. As a result, the shaft is lightweight yet firm, improving the feeling for athletic golfers.

[0088] The improvement in torsional rigidity due to the hoop layer is more effective the further outward the hoop layer is located. By arranging a longer hoop layer on the outside, the effect of the crushing rigidity due to the hoop layer can be maximized for the entire shaft 6. This contributes to reducing the weight of the shaft 6.

[0089] The second hoop layer f2 is disposed outside the first hoop layer f1. Thus, the tip side end of the first hoop layer f1 is covered by the second hoop layer f2. The third hoop layer f3 is disposed outside the second hoop layer f2. Thus, the tip side end of the second hoop layer f2 is covered by the third hoop layer f3. These configurations can stabilize the crushing deformation at the end positions of the partial hoop layers and improve the feeling.

[0090] At least one of the first hoop layer f1 and the second hoop layer f2 is thicker than the third hoop layer f3. This reinforces the crushing rigidity of the butt side, which has a larger outer diameter, and can further improve the firmness of the club. In the shaft 6, the second hoop layer f2 is thicker than the third hoop layer f3. In the shaft 6, the second hoop layer f2 is thicker than the first hoop layer f1. In the shaft 6, the first hoop layer f1 is thinner than the third hoop layer f3. The first hoop layer f1 may be thicker than the third hoop layer f3. From the viewpoint of firmness, it is preferable that the second hoop layer f2 is thicker than the third hoop layer f3.

[0091] From the standpoint of shaft weight, the thickness of the first hoop layer f1 is preferably 0.035 mm or less, more preferably 0.034 mm or less, and more preferably 0.033 mm or less. From the standpoint of the crushing strength of the butt end of the shaft 6, the thickness of the first hoop layer f1 is preferably 0.020 mm or more, more preferably 0.021 mm or more, and more preferably 0.022 mm or more.

[0092] From the standpoint of shaft weight, the thickness of the second hoop layer f2 is preferably 0.045 mm or less, more preferably 0.040 mm or less, and more preferably 0.035 mm or less. From the standpoint of firmness, the thickness of the second hoop layer f2 is preferably 0.028 mm or more, more preferably 0.030 mm or more, and more preferably 0.032 mm or more.

[0093] From the viewpoint of shaft weight, the thickness of the third hoop layer f3 is preferably 0.030 mm or less, more preferably 0.029 mm or less, and more preferably 0.028 mm or less. From the viewpoints of crushing strength and firmness, the thickness of the third hoop layer f3 is preferably 0.020 mm or more, more preferably 0.021 mm or more, and more preferably 0.022 mm or more.

[0094] In Fig. 2, the length of the first hoop layer f1 is indicated by a double-headed arrow L1. From the viewpoint of reinforcing the butt portion of the shaft 6 to improve the firmness, the length L1 of the first hoop layer f1 is preferably 300 mm or more, more preferably 350 mm or more, and more preferably 400 mm or more. From the viewpoint of selectively reinforcing the area closer to the butt, the length L1 of the first hoop layer f1 is preferably 550 mm or less, more preferably 540 mm or less, and more preferably 530 mm or less.

[0095] In Fig. 2, the length of the second hoop layer f2 is indicated by a double-headed arrow L2. From the viewpoint of making the second hoop layer f2 longer than the first hoop layer f1 to enhance a sense of firmness, the length L2 of the second hoop layer f2 is preferably 500 mm or more, more preferably 550 mm or more, and more preferably 600 mm or more. From the viewpoint of reducing the weight of the shaft 6, the length L2 of the second hoop layer f2 is preferably 775 mm or less, more preferably 765 mm or less, and more preferably 755 mm or less.

[0096] The shaft 6 has a fiber elastic modulus of 10t / mm 2 The shaft 6 includes a low elasticity tip partial layer which is as follows. In FIG. 2, the low elasticity tip partial layer is a tip partial straight layer s1. The low elasticity tip partial layer s1 enhances the impact absorption energy of the tip portion of the shaft 6. The low elasticity tip partial layer s1 is a glass fiber reinforced layer reinforced with glass fiber. This further enhances the impact absorption energy. The shaft 6 has a thick portion in which the low elasticity tip partial layer s1 is wound in two or more plies. The length of this thick portion is 100 mm or more (250 mm or less). This thick portion further enhances the impact absorption energy.

[0097] The batt partial straight layer includes a first batt straight layer b1 having a first length and a second batt straight layer b2 having a second length. The second batt straight layer b2 is longer than the first batt straight layer b1. In the embodiment of FIG. 2, the first batt straight layer b1 is layer s6, and the second batt straight layer b2 is layer s8. The first batt straight layer b1 is in contact with the first hoop layer f1. The second batt straight layer b2 is in contact with the second hoop layer f2. The second batt straight layer b2 is located outside the first batt straight layer b1.

[0098] The different first butt straight layer b1 and second butt straight layer b2 reinforce the bending rigidity of the butt side with a larger outer diameter. As a result, the club is lightweight yet firm, improving the feeling for athletic golfers. This effect, combined with the hoop layers f1 to f3, enhances the feeling.

[0099] The preferred range of the length of the first batt straight layer b1 is the same as the length L1 of the first hoop layer f1 The preferred range of the length of the second batt straight layer b2 is the same as the length L2 of the second hoop layer f2.

[0100] The shaft 6 has a plurality of butt partial straight layers s6, s8. Among them, the longest butt partial straight layer is also referred to as the longest butt straight layer. In this embodiment, the longest butt straight layer m2 is the layer s8. In this embodiment, the longest butt straight layer m2 is the second butt straight layer b2.

[0101] The chip partial straight layer has a first chip straight layer t1 having a first length, a second chip straight layer t2 having a second length, a third chip straight layer t3 having a third length, and a fourth chip straight layer t4 having a fourth length. In the embodiment of FIG. 2, the second chip straight layer t2 is longer than the first chip straight layer t1. The third chip straight layer t3 is longer than the second chip straight layer t2. The fourth chip straight layer t4 is longer than the third chip straight layer t3.

[0102] In the embodiment of Fig. 2, the first chip straight layer t1 is layer s16, the second chip straight layer t2 is layer s9, the third chip straight layer t3 is layer s15, and the fourth chip straight layer t4 is layer s11. Note that the layers s1 and s2 can also be the first chip straight layer t1.

[0103] By reducing the full-length straight layers and increasing the partial straight layers, the amount of prepreg used can be reduced, and the shaft weight can be suppressed. However, stress can be concentrated at the ends of the partial straight layers during bending deformation. By varying the length of the tip straight layers, the positions of the ends of the tip straight layers are dispersed in the axial direction. In addition, the strength can be increased closer to the tip side, which is closer to the head and requires more bending strength. This can improve strength.

[0104] The first chip straight layer t1 is located outside the fourth chip straight layer t4, the second chip straight layer t2 is located inside the fourth chip straight layer t4, and the third chip straight layer t3 is located outside the fourth chip straight layer t4.

[0105] At least one of the first chip straight layer t1, the second chip straight layer t2, and the third chip straight layer t3 is located inside the fourth chip straight layer t4. At least one of the first chip straight layer t1, the second chip straight layer t2, and the third chip straight layer t3 is located outside the fourth chip straight layer t4. With this configuration, the positions of the ends of the chip straight layers are dispersed in the radial direction. This can improve strength.

[0106] The shaft 6 is provided with a plurality of tip partial straight layers. Among them, the longest tip partial straight layer is also referred to as the longest tip straight layer. In the embodiment of FIG. 2, the longest tip straight layer m1 is the layer s11. The longest tip straight layer m1 is the fourth tip straight layer t4.

[0107] The shaft 6 has an overlapping portion R1 where the longest tip straight layer m1 and the second butt straight layer b2 overlap in the axial direction (see FIG. 2). The overlapping portion R1 is formed by the longest tip straight layer m1 and the longest butt straight layer m2 overlapping in the axial direction.

[0108] The overlapping portion R1 is located in the middle of the shaft 6. When the shaft 6 flexes during a swing, bending deformation is large in this middle portion. The overlapping portion R1 increases the bending rigidity of the middle portion of the shaft 6. The overlapping portion R1 increases the rigidity of a portion that is prone to bending. This overlapping portion R1 increases the sense of solidity and contributes to an improved feeling.

[0109] The second hoop layer f2 is disposed on at least a part of the overlapping portion R1. This can further enhance the sense of firmness and feeling. In this embodiment, the second hoop layer f2 is disposed on the entire overlapping portion R1 (see FIG. 2).

[0110] From the viewpoint of a firm feel for athletic golfers, the length of the overlapping portion R1 is preferably 100 mm or more, more preferably 150 mm or more, and more preferably 200 mm or more. From the viewpoint of reducing the weight of the shaft 6, the length of the overlapping portion R1 is preferably 400 mm or less, more preferably 350 mm or less, and more preferably 300 mm or less.

[0111] The overlapping portion R1 has an axial center C1 (see FIG. 2). From the viewpoint of a firm feel for athletic golfers, it is preferable that the axial center position of the overlapping portion R1 is located between the first position P1 and the second position P2.

[0112] The outer diameter of the shaft 6 at a position 550 mm from the tip end Tp is set to D5 (mm). The outer diameter of the shaft 6 at a position 950 mm from the tip end Tp is set to D9 (mm). The crushing strength at a position 550 mm from the tip end Tp is set to F5 (kgf). The crushing strength at a position 950 mm from the tip end Tp is set to F9 (kgf).

[0113] If F5 / D5 is small, the crush strength relative to the outer diameter is small, resulting in a lack of firmness and poor feeling. From this viewpoint, F5 / D5 is preferably 1.5 or more, more preferably 1.55 or more, and even more preferably 1.6 or more. If F5 / D5 is large, the crush strength relative to the outer diameter is high. In this case, while there is room for reduction in the hoop layer, layers other than the hoop layer may be insufficient, resulting in poor feeling. From this viewpoint, F5 / D5 is preferably 2.5 or less, more preferably 2.4 or less, and even more preferably 2.3 or less.

[0114] If F9 / D9 is small, the crush strength relative to the outer diameter is small, resulting in a lack of firmness and poor feeling. From this viewpoint, F9 / D9 is preferably 1.0 or more, more preferably 1.05 or more, more preferably 1.08 or more, and even more preferably 1.1 or more. If F9 / D9 is large, the crush strength relative to the outer diameter is high. In this case, while there is room for reduction in the hoop layer, layers other than the hoop layer may be insufficient, resulting in poor feeling. From this viewpoint, F9 / D9 is preferably 2.0 or less, more preferably 1.9 or less, and even more preferably 1.8 or less.

[0115] If the difference (F5-F9) is large, the crushing strength of the butt side is relatively small, and the feeling of firmness may be insufficient. From this viewpoint, the difference (F5-F9) is preferably 4 kgf or less, more preferably 3.9 kgf or less, more preferably 3.8 kgf or less, and more preferably 3.5 kgf or less. Considering the limit of the design freedom, the difference (F5-F9) is preferably 1.0 kgf or more, more preferably 1.5 kgf or more, and more preferably 2.0 kgf or more.

[0116] From the viewpoint of distance, the shaft length Ls is preferably 1080 mm or more, more preferably 1130 mm or more, and more preferably 1150 mm or more. Considering the restriction on club length in the golf rules, the shaft length Ls is preferably 1210 mm or less, more preferably 1200 mm or less, and more preferably 1190 mm or less.

[0117] From the viewpoint of increasing the head speed, the shaft weight is preferably equal to or less than 50 g, more preferably equal to or less than 49 g, and still more preferably equal to or less than 48 g. From the viewpoint of design freedom, the shaft weight is preferably equal to or more than 30 g, more preferably equal to or more than 32 g, and still more preferably equal to or more than 34 g.

[0118] Below are examples of prepregs that can be used in the shafts of the present disclosure.

[0119] [Table 1]

[0120] [Table 2] EXAMPLES

[0121] [Example 1] According to the manufacturing process described above, a shaft similar to shaft 6 was produced. The sheet configuration of the shaft was as shown in FIG. 2. The length Ls of the shaft was 1168 mm. The shaft weight was 47 g. The shaft torque was 6.2°. A driver head and a grip were attached to the obtained shaft to obtain a golf club. As the driver head, a head attached to a product name "SRIXON ZX7 driver (loft angle 10.5°)" manufactured by Sumitomo Rubber Industries, Ltd. was used.

[0122] In Example 1, layers other than the tip portion straight layer s1 were carbon fiber reinforced layers, but the tip portion straight layer s1 was a glass fiber reinforced layer. The glass fiber reinforced layer had a fiber elastic modulus (tensile elastic modulus) of 7t / mm 2 The glass fiber reinforced prepreg was used. The thickness of the layer s7 (second hoop layer f2) was 0.034 mm. The prepreg of this layer s7 was manufactured by Toray Industries, Inc. under the trade name "805S-3". The thickness of the layer s12 (third hoop layer f3) was 0.028 mm. The prepreg of this layer s12 was manufactured by Toray Industries, Inc. under the trade name "8053S-3". The length L1 was 500 mm, and the length L2 was 720 mm. The length of the tip portion straight layer s11 was 698 mm.

[0123] The strength of Example 1 was as follows. The three-point bending strength was 205 kgf at a position 90 mm from the tip end Tp, 78 kgf at a position 175 mm from the tip end Tp, 73 kgf at a position 525 mm from the tip end Tp, and 105 kgf at a position 175 mm from the butt end Bt. The impact absorption energy of the tip was 3.7 J. The crushing strength was 19 kgf at a position 550 mm from the tip end Tp, 18 kgf at a position 650 mm from the tip end Tp, 17 kgf at a position 750 mm from the tip end Tp, 16.5 kgf at a position 850 mm from the tip end Tp, and 16 kgf at a position 950 mm from the tip end Tp. The measurement methods for the three-point bending strength, impact absorption energy, and crushing strength are as described above.

[0124] [Example 2] A shaft and a golf club of Example 2 were obtained in the same manner as in Example 1, except that the prepreg of the second hoop layer f2 was the same as the prepreg (thickness 0.028 mm) of the third hoop layer f3.

[0125] [Comparative Example 1] A shaft and a golf club of Comparative Example 1 were obtained in the same manner as in Example 1, except that the second hoop layer f2 was omitted.

[0126] [Comparative Example 2] A shaft and a golf club of Comparative Example 1 were obtained in the same manner as in Example 1, except that the length L2 of the second hoop layer f2 was shortened to be the same as the length L1 of the first hoop layer f1.

[0127] [Comparative Example 3] A shaft and a golf club of Comparative Example 3 were obtained in the same manner as in Example 1, except that the second butt straight layer b2 was made into a hoop layer by changing only the fiber direction of the same prepreg.

[0128] The evaluation results of the examples and comparative examples are shown in Table 3 below.

[0129] [Table 3]

[0130] The evaluation methods for the forward flex, reverse flex and strength are as described above. The evaluation method for the feeling is as follows.

[0131] <Feeling> Five athletic golfers with a driver head speed of 43-46 m / s or more hit five balls with each club. Each tester rated the feeling of the shaft using a maximum of 10 points. The higher the score, the better the feeling. The golf ball used was a product name "SRIXON Z-STAR XV" manufactured by Sumitomo Rubber Industries. The average score is shown in Table 3 above.

[0132] As shown in Table 3, the examples were rated higher than the comparative examples.

[0133] The following notes are part of the invention contained in this disclosure. [Appendix 1] A golf club shaft formed of a plurality of fiber reinforced resin layers and having a tip end and a butt end, The shaft weight is 50g or less. The forward flex is 110 mm or less and the reverse flex is 100 mm or less, The shaft torque is 4.0° or more and 6.5° or less, The plurality of fiber reinforced resin layers include a first hoop layer disposed from the bat end to a first position, a second hoop layer disposed from the bat end to a second position and longer than the first hoop layer, and a third hoop layer disposed from the bat end to a third position and longer than the second hoop layer, When the outer diameter of the shaft at a position 550 mm from the tip end is D5 (mm), the outer diameter of the shaft at a position 950 mm from the tip end is D9 (mm), the crushing strength at a position 550 mm from the tip end is F5 (kgf), and the crushing strength at a position 950 mm from the tip end is F9 (kgf), F5 / D5 is 1.5 or more and 2.5 or less, F9 / D9 is 1.0 or more and 2.0 or less, A golf club shaft with a difference (F5-F9) of 4kgf or less. [Appendix 2] a three-point bending strength of 190 kgf or more at a position 90 mm from the tip end, 70 kgf or more at a position 175 mm from the tip end, 65 kgf or more at a position 525 mm from the tip end, and 90 kgf or more at a position 175 mm from the butt end; The impact absorption energy of the tip is 3.4J or more. 2. The golf club shaft according to claim 1, wherein the crushing strength is 11 kgf or more at a position 550 mm from the tip end, 11 kgf or more at a position 650 mm from the tip end, 11 kgf or more at a position 750 mm from the tip end, 11 kgf or more at a position 850 mm from the tip end, and 11 kgf or more at a position 950 mm from the tip end. [Appendix 3] The first hoop layer and the second hoop layer are butt partial hoop layers, the third hoop layer is a full length hoop layer; The second hoop layer is disposed on the outside of the first hoop layer, 3. The golf club shaft according to claim 1, wherein the third hoop layer is disposed outside the second hoop layer. [Appendix 4] The length of the first hoop layer is 300 mm or more and 550 mm or less, 4. The golf club shaft according to claim 3, wherein the second hoop layer has a length of 500 mm or more and 775 mm or less. [Appendix 5] The plurality of fiber reinforced resin layers include a chip partial layer, The chip partial layer has a fiber elastic modulus of 10t / mm 2 5. A golf club shaft according to any one of claims 1 to 4, comprising a low elasticity tip partial layer, [Appendix 6] 6. The golf club shaft according to claim 1, wherein at least one of the first hoop layer and the second hoop layer is thicker than the third hoop layer. [Appendix 7] The plurality of fiber reinforced resin layers include a plurality of tip portion straight layers having different lengths and a plurality of butt portion straight layers having different lengths, The plurality of tip partial straight layers includes a longest tip straight layer, The plurality of butt partial straight layers include a longest butt straight layer, 7. The golf club shaft according to claim 1, wherein an overlapping portion is formed between the longest tip straight layer and the longest butt straight layer in an axial direction. [Appendix 8] an axial center of the overlapping portion is located between the first position and the second position; 8. The golf club shaft of claim 7, wherein the second hoop layer is disposed in the overlapping portion. [Explanation of symbols]

[0134] 2. Golf clubs 4 Head 6. Shaft 8. Grip s1~s16: Prepreg sheets (layers) f1: First hoop layer f2: Second hoop layer f3: Third hoop layer P1...1st position P2...2nd position P3...3rd position b1: First butt straight layer b2: Second butt straight layer m1: Longest tip straight layer m2 ···Longest butt straight layer Bt: Butt end Tp: Chip end

Claims

1. A golf club shaft formed of a plurality of fiber reinforced resin layers and having a tip end and a butt end, The shaft weight is 50 g or less, The forward flex is 110 mm or less and the reverse flex is 100 mm or less, The shaft torque is equal to or greater than 4.0° and equal to or less than 6.5°, The plurality of fiber reinforced resin layers include a first hoop layer disposed from the bat end to a first position, a second hoop layer disposed from the bat end to a second position and longer than the first hoop layer, and a third hoop layer disposed from the bat end to a third position and longer than the second hoop layer, When the outer diameter of the shaft at a position 550 mm from the tip end is D5 (mm), the outer diameter of the shaft at a position 950 mm from the tip end is D9 (mm), the crushing strength at a position 550 mm from the tip end is F5 (kgf), and the crushing strength at a position 950 mm from the tip end is F9 (kgf), F5 / D5 is 1.5 or more and 2.5 or less, F9 / D9 is 1.0 or more and 2.0 or less, A golf club shaft in which the difference (F5-F9) is 4 kgf or less.

2. a three-point bending strength of 190 kgf or more at a position 90 mm from the tip end, 70 kgf or more at a position 175 mm from the tip end, 65 kgf or more at a position 525 mm from the tip end, and 90 kgf or more at a position 175 mm from the butt end; The impact absorption energy of the tip is 3.4 J or more, 2. The golf club shaft of claim 1, wherein the crushing strength is 11 kgf or more at a position 550 mm from the tip end, 11 kgf or more at a position 650 mm from the tip end, 11 kgf or more at a position 750 mm from the tip end, 11 kgf or more at a position 850 mm from the tip end, and 11 kgf or more at a position 950 mm from the tip end.

3. the first hoop layer and the second hoop layer are butt partial hoop layers; the third hoop layer is a full length hoop layer; The second hoop layer is disposed on the outside of the first hoop layer, 3. The golf club shaft according to claim 1, wherein the third hoop layer is disposed outside the second hoop layer.

4. The length of the first hoop layer is 300 mm or more and 550 mm or less, 4. The golf club shaft according to claim 3, wherein the second hoop layer has a length of 500 mm or more and 775 mm or less.

5. The plurality of fiber reinforced resin layers include a chip partial layer, The tip partial layer has a fiber elastic modulus of 10t / mm ２ 5. The golf club shaft according to claim 1, further comprising a low elasticity tip portion layer having a thickness of 0.1 to 0.5 mm.

6. 6. The golf club shaft according to claim 1, wherein at least one of the first hoop layer and the second hoop layer is thicker than the third hoop layer.

7. The plurality of fiber reinforced resin layers include a plurality of tip portion straight layers having different lengths and a plurality of butt portion straight layers having different lengths, The plurality of tip partial straight layers includes a longest tip straight layer, The plurality of butt partial straight layers include a longest butt straight layer, 7. The golf club shaft according to claim 1, further comprising an overlapping portion formed between the longest tip straight layer and the longest butt straight layer in an axial direction.

8. an axial center of the overlapping portion is located between the first position and the second position; The golf club shaft of claim 7 , wherein the second hoop layer is disposed in the overlapping portion.

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