JP2009219652A - Golf club shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-weight golf club shaft which more resists actual use on the basis of loads generated at respective portions of a golf club when using the golf club. <P>SOLUTION: Along the whole length of the shaft (100) of the golf club, the shaft club includes a bias layer (111) wherein reinforced fibers of a fiber-reinforced synthetic resin layer are oriented at an angle tilted by ±35 to ±55° with respect to an axial direction and a straight layer (112) wherein the reinforced fibers are oriented in the axial direction. A front side (110) and a base side (120) respectively includes a front side circumferential direction layer (114) a base side circumferential direction layer (123) where the reinforced fibers are oriented in a circumferential direction. The length of the layer (114) in the axial direction is set to be 20% to 50% of the shaft (100) from the from a front end part to the base side (120). The length of the layer (123) in the axial direction is set equal to the length of a grip (3) or more. An intermediate section (130) inserted between the layer (114) and the layer (123) exceeds 30% of the whole length. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a golf club shaft comprising a plurality of fiber-reinforced synthetic resin layers.

  In order to provide a golf club that is easier to handle while maintaining its function, it is one of the issues to reduce the weight of the shaft of the golf club. Therefore, fiber reinforced resin shafts are widely known. That is, a shaft made of a fiber reinforced prepreg in which a reinforcing fiber such as carbon fiber, glass fiber, or boron fiber is impregnated with a synthetic resin is superior in specific strength and specific rigidity as compared with a conventional metal.

The shaft has an inclination direction fiber layer in which the reinforcing fiber is inclined with respect to the axis, an axial length direction fiber layer in the direction parallel to the axis, and a circumferential fiber in which the reinforcement fiber is in the circumferential direction with respect to the axis. A layer is generally selected by arbitrarily selecting a layer, winding it around a metal core, and heating and firing the layer (for example, Patent Document 1).
The shaft made of fiber reinforced resin changes the physical properties of the shaft greatly depending on the direction of the reinforcing fiber and the lamination conditions, and also depending on the shape and thickness of the shaft. It is necessary to perform manufacturing.

For example, in order to reduce the weight of the shaft while maintaining the crushing strength of the shaft, the hoop layer (circumferential fiber layer) in which reinforcing fibers are oriented at an angle of 90 degrees with respect to the axial direction of the shaft is removed. A technique is known in which a hoop layer is formed only in a range in which the relationship between the outer diameter and the thickness of the shaft excluding the hoop layer at the portion satisfies the outer diameter / thickness ≧ 14.0 (for example, patents) Reference 1). This technology regulates the relationship between the outer diameter and the wall thickness, and the part where the diameter is larger than a certain value and the wall thickness is thin is structurally easily crushed, so it is locally reinforced with a circumferential fiber layer. It is.
JP 2004-57673 A

  However, the crushing strength required for each part of the shaft usually varies depending on the fiber reinforced layer lamination conditions such as the fiber direction, type and number of layers of the fiber reinforced prepreg, actual use conditions, and the like. Therefore, when only the relationship between the outer diameter and the wall thickness is specified as in the prior art described above, it is difficult to reduce the weight while maintaining the necessary strength when considering the various conditions described above. There was a case.

  That is, when the winding of the circumferential fiber layer is limited only by the relationship between the outer diameter and the wall thickness (for example, Patent Document 1), the axial position of the shaft around which the circumferential fiber layer is wound, the player Depending on the conditions for use as a golf club having individual differences, there is a risk that the weight may increase if an attempt is made to maintain the strength necessary to prevent breakage or the like.

  An object of the present invention is to provide a lightweight golf club shaft that can withstand actual use based on the load generated at each part of the golf club when the golf club is used.

  In order to solve the above-described problems, the present invention includes a front side provided with a club head at a tip portion, and an original side on which a grip is disposed, and gradually increases the outer diameter from the front side to the original side. A golf club having a shaft composed of a plurality of fiber-reinforced synthetic resin layers, wherein the reinforcing fibers of the fiber-reinforced synthetic resin layer are ± 35 degrees or more and ± 55 degrees or less with respect to the axial direction over the entire length of the shaft. And a straight layer in which the reinforcing fibers of the fiber-reinforced synthetic resin layer are aligned in the axial direction, and the reinforcing fibers are provided on the front side and the original side, respectively. Further comprising a front-side circumferential layer and a former-side circumferential layer oriented in the circumferential direction, and the length of the front-side circumferential layer in the axial direction extends from the tip to the former side of the shaft. 20% or more and 50% or less of the total length, The axial length of the side circumferential layer is at least the length of the grip, and the intermediate portion sandwiched between the front circumferential layer and the original circumferential layer has a length exceeding 30% of the total length. It is characterized by.

With such a configuration, bending strength, torsional strength, and crushing (crushing) strength can be efficiently reinforced, and a lightweight, high-strength shaft can be obtained.
In addition, the shaft side can be prevented from being damaged even if an abnormal crushing load is applied to the grip during use, and the shaft end can be prevented from being damaged even if the vicinity of the head is greatly bent during swinging. Can be improved and stabilized. And since a circumferential direction layer is provided only in a required part, ultimate weight reduction, strength improvement, and stabilization can be achieved. Since the middle part of the shaft can tolerate expansion and contraction of the reinforcing fiber and deformation of the shaft cross section against bending stress, when the golf club is swung, the maximum point of bending of the shaft moves relatively from the front side to the middle part As a result, the kick point portion can be sufficiently sticky, and a golf club shaft that is easy to swing and is easy to swing.

Here, the kick point is generally used in evaluating a shaft of a golf club and is defined as follows.
That is, the kick point is based on a straight line connecting one end and the other end of the shaft when the shaft is bent by applying a compressive force simultaneously from one end of the shaft to the other end and from the other end to the other end. If the axis line curve of the bent shaft is defined as the shaft line, the farthest vertex position of the shaft line with respect to this reference line. In the measurement of the kick point, the apex position when the distance between the reference line and the shaft line reaches a maximum of 5 cm is set as the kick point when a compression force is applied from both ends to bend the shaft.

  In addition to the above-described configuration, the steep taper portion includes a steep taper portion in which the outer diameter of the shaft is conically reduced from the original side to the front side at the intermediate portion and closer to the original side from the kick point. When the other taper portion is provided on the front side and / or the original side in the axial direction, the taper of the steep taper portion is preferably larger than that of the other taper portion.

  With this configuration, the range in which the shaft has a small diameter can be lengthened and the range that is easily deformed can be expanded, so that the crushing strength can be stabilized, the head can be returned smoothly during the swing, and the swing operation is easy. It becomes the shaft of a golf club.

  In addition to the above configuration, the front side includes the bias layer on the inner peripheral side, the straight layer on the outer peripheral side, the bias layer and the straight layer, or a plurality of the straight layers. A front-side circumferential layer, wherein the former side is adjacent to the inner circumferential side of the bias layer on the inner circumferential side, the straight layer on the outer circumferential side, and the inner circumferential side of the outermost straight layer. And a layer.

With this configuration, the front side circumferential layer is wound between the bias layer and the straight layer, or between a plurality of straight layers, so that the bending rigidity is substantially increased by concentrating the straight layer on the outer layer side. Crushing strength can be improved while maximizing. Furthermore, by concentrating different fiber direction layers, ie, bias layer, circumferential direction layer (front side circumferential direction layer), and straight layer, within a certain range, fibers in each direction can be firmly fixed, and impact when hitting a ball Stable strength can be obtained against a torsional load.
Moreover, since the former side circumferential direction layer is wound inside the outermost layer of the straight layer, it is possible to prevent the meandering of the fibers in the circumferential layer and the cutting of the fibers during surface polishing, and the maximum amount with a small amount of fibers. A reinforcing effect against limit squashing can be obtained. Therefore, the golf club shaft can be reduced in weight and strength required for each part of one shaft.

  In addition to the configuration, the front side circumferential layer and the original side circumferential layer are thinner than the bias layer and the straight layer, and the synthetic resin impregnation amount is smaller than that of the bias layer and the straight layer. It is preferably formed by winding a single layer or less than two layers with a large number of prepreg sheets.

  With this configuration, the thickness of the front side circumferential layer and the original side circumferential layer is the minimum amount of reinforcement, and the synthetic resin impregnation amount of these layers is larger than the other layers and is oriented in different fiber directions. Therefore, peeling is prevented, so that the shaft of the golf club can be further reduced in weight, improved in strength and stabilized.

  According to such a golf club shaft configuration, it is possible to provide a lightweight golf club shaft that can withstand actual use based on the load generated at each part of the golf club when the golf club is used. .

[First Embodiment]
A shaft of a golf club according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an external side view of a golf club 1 having a shaft according to the present embodiment. A golf club 1 includes a tubular shaft 100 having a hollow portion composed of a plurality of fiber-reinforced synthetic resin layers to be described later, a head 2 attached to one end of the shaft 100, and a grip disposed on the other end side. 3.
The shaft 100 has an outer diameter that gradually increases from the front side 110 to the base side 120, where one end side where the head 2 is provided is the front side 110 and the other end side where the grip 3 is disposed is the base side 120. As described later, it has a shape in which a plurality of tapers are combined.

  There is an intermediate portion 130 between the front side 110 and the original side 120, and the center of gravity G of the golf club 1 is located in the intermediate portion 130. In the present embodiment, when the player swings the golf club, the kick point KP at which the bending of the shaft 100 becomes the maximum is positioned near the center of gravity G and closer to the head 2.

Next, each part of the shaft 100 according to the present embodiment will be described with reference to the drawings. 2 is an enlarged sectional view of the front side 110 shown in FIG. 1A, FIG. 3 is an enlarged sectional view of the original side 120 shown in FIG. 1B, and FIG. 4 is an intermediate portion 130 shown in FIG. FIG.
Each part will be described below with reference to FIGS. 2 to 4, but a bias layer 111 and a straight layer 112 described later are stacked over the entire length of the shaft 100.

As shown in FIG. 2, the front side 110 has a straight layer 113 for reinforcing the high load on the front side 110 on the innermost side (side closer to the axis X), and a bias on the outer peripheral side adjacent to the straight layer 113. The layer 111 includes a straight layer 112 on the outermost peripheral side, and a front-side circumferential direction layer 114 laminated between the bias layer 111 and the straight layer 112.
Here, the bias layer 111 is a fiber reinforced synthetic resin layer in which the reinforcing fibers are oriented at an inclination angle of ± 35 degrees or more and ± 55 degrees or less with respect to the axis X direction, and the straight layers 112 and 113 are the reinforcing fibers having the axis line. It is a fiber reinforced synthetic resin layer oriented in the X direction, and the front side circumferential direction layer 114 is a fiber reinforced synthetic resin layer in which reinforced fibers are oriented in the circumferential direction.

  In addition, the lamination | stacking number of each synthetic resin layer shown by FIGS. 2-4 is an example which shows a schematic structure, and is not limited to the number of layers of a figure, It sets suitably according to load conditions, the material to be used, etc. In this embodiment, in addition to the straight layer 112 laminated | stacked over the shaft full length, the straight layer 113 which reinforces a front side locally is provided. Further, the front side circumferential direction layer 114 can be laminated between the straight layers 112 and 113.

  The orientation of the reinforcing fibers of the straight layers 112 and 113 is in the range of approximately 0 to ± 10 degrees with respect to the axis X direction, and the orientation of the reinforcing fibers of the front circumferential layer 114 is approximately 90 degrees ± 10 with respect to the axis X direction. It may be in the range of degrees.

  As the reinforcing fiber, fibers such as carbon fiber, glass fiber, and boron fiber that are generally used as high-performance reinforcing fibers can be applied, but carbon fiber is preferable because it is lightweight and has high strength. Further, continuous fibers are preferable, and the arrangement form of the fibers can be appropriately set, but a unidirectional, sheet-like prepreg is preferable.

  As shown in FIG. 1, the range HA in which the front side circumferential layer 114 is provided extends over a length of 20% to 50% of the total length L from the front side of the shaft including the fixing position of the head 2. With this configuration, damage can be prevented even if the vicinity of the head 2 is greatly bent during the swing, so that strength can be improved and stabilized.

  As shown in FIG. 3, the original side 120 includes the innermost bias layer 111, the outermost straight layer 112a, the straight layer 121b on the inner peripheral side of the straight layer 112a, the straight layer 121a and the straight layer. The former side circumferential direction layer 123 between 121b. The orientations of the reinforcing fibers in the bias layer 111, the straight layer 122, and the former-side circumferential direction layer 123 are the same as those described above. The straight layer is formed by laminating a straight layer 112, which is a fiber-reinforced synthetic resin layer over the entire length of the shaft, and a straight layer 122 that is laminated according to load conditions, material characteristics, and the like, similar to the straight layer on the front side 110. Yes.

In addition, the former side circumferential direction layer 123 shall be within a range GA of 150 mm or less from the portion where the grip 3 is disposed (the broken line portion of the former side 120 in FIG. 1) and one end of the grip 3 to the front side 110. However, it is not limited to this.
With this configuration, the original side 120 can prevent breakage even when an abnormal crushing load is applied during use, and the strength can be improved and stabilized. Since the circumferential layer is wound only on necessary portions, the ultimate weight reduction, strength improvement, and stabilization can be achieved.

  Further, since the original side circumferential direction layer 123 is laminated and wound on the inner circumference side of the outermost straight layer 112a, it prevents the meandering of the fibers in the circumferential layer and the fiber cutting during surface polishing. It is possible to obtain the maximum crushing reinforcement effect with a small amount of fibers. Therefore, it is possible to obtain a golf club that achieves weight reduction and strength improvement required for each part of one shaft 100.

The intermediate portion 130 is a portion in the axis X direction of the shaft 100 sandwiched between the front-side circumferential layer 114 and the original-side circumferential layer 123, and as shown in FIG. Unlike the above, there is no circumferential layer, and the bias layer 111 and the straight layer 112 are included. Here, the intermediate portion is assumed to exceed 30% of the total length.
With such a configuration, the expansion and contraction of the reinforcing fiber and the deformation of the shaft cross section can be allowed with respect to the bending stress. Therefore, the kick point KP (see FIG. 1) can be relatively easily moved from the front portion to the intermediate portion, and the kick point KP portion is sufficient. It is possible to obtain a golf club that is easy to swing and can be obtained without being bent (bent).

  As described above, the shaft 100 has an outer diameter gradually increased from the front side 110 to the base side 120 (see FIG. 1), and a shape in which a plurality of tapers are combined is also applied as described later. As shown in FIG. 4B, the intermediate portion 130 has a steep taper portion ST formed closer to the original side 120 from the kick point KP. The steep taper part ST is formed to have a larger taper than the taper part T1 on the front side 110 in the axial center X direction and the taper part T2 on the original side 120. In other words, the taper portion T1 and the taper portion T2 are connected by the steep taper portion ST having a large taper.

  In the present embodiment, when the taper of the taper portion T1 is 5/1000 or less and the taper of the taper portion T2 is 3/1000 or less, the taper of the steep taper portion ST is 25/1000 or more, preferably 30/1000 or more. It is said. That is, the difference between the steep taper portion ST and the front and rear taper portions T1, T2 is 15/1000 or more, preferably 20/1000 or more. From the viewpoint of strength over the entire length of the shaft 100 to which the head 2 and the grip 3 are attached, the difference between the steep taper portion ST and the front and rear taper portions T1, T2 is preferably 55/1000 or less. However, it is needless to say that these specifications are set based on load conditions, material characteristics, use conditions, and the like, and are not limited to the numerical values described above.

  With this configuration, the small range of the shaft intermediate portion can be lengthened and the range where the shaft intermediate portion 30 is easily bent can be expanded, so that the crushing strength can be stabilized and the head 2 can be smoothly returned during the swing. This is a golf club that can be easily swung.

Next, a preferred prepreg applied to the bias layer, the straight layer, and the circumferential layer will be described.
The prepreg is composed of reinforcing fiber and synthetic resin, and is formed by arranging a plurality of reinforcing fibers and impregnating the synthetic resin, and the fiber is reinforced by curing the resin by subsequent processing. It becomes.

  In this embodiment, carbon fibers are used as reinforcing fibers for the bias layer, straight layer, and circumferential layer because of high strength and light weight, but glass fibers, boron fibers, and the like can also be used. As an example of the physical properties of this carbon fiber, the tensile modulus is 54 GPa to 588 GPa, and the strength is 1100 MPa to 3820 MPa.

As the synthetic resin impregnated in the reinforcing fiber, an epoxy resin which is a thermosetting resin having excellent strength is used. However, a phenol resin, a furan resin, a thermoplastic resin, or the like may be used depending on conditions.
The synthetic resin impregnation amount is preferably 15 to 35 wt% (weight%), more preferably 20 to 30 wt% in the bias layer and the straight layer, and the synthetic resin impregnation amount in the circumferential layer is preferably 30 to 60 wt%. More preferably, it is 34-56 wt%.
With this configuration, the thickness of the circumferential layer is the minimum amount of reinforcement, and the amount of resin impregnation is greater than that of the other main body layers to prevent peeling in different fiber directions, thus further reducing weight and improving strength. The golf club can be stabilized.

Next, an example of a laminated structure (cut shape) of the prepreg according to the present embodiment will be described with reference to the drawings. FIG. 5 shows a laminated configuration, and shows a prepreg cut shape applied to the bias layer, the straight layer, the front side circumferential direction layer, and the original side circumferential direction layer. In the following description, FIG. 1 is referred to as appropriate.
The shaft 100 is manufactured by a sheet winding method using these prepregs, and is sequentially cut from the inner periphery side in the order of the cut prepregs shown in FIGS. 5 (b) to 5 (h). ) To be laminated. Then, the synthetic resin is cured by heating and pressurizing and integrally molded, and then the cored bar 150 is pulled out and the shaft 100 is molded.

  Here, the thin line in the figure of FIG.5 (b)-(h) has shown the orientation of the reinforced fiber. Moreover, in the following description, since the target is not a molded resin layer but a prepreg, the reference numbers are changed even if the names are the same as or similar to the names of the layers shown in FIGS. .

As shown in FIG. 5A, the core metal 150 has a diameter of the front side 151 such that the front side 151 to which the head 2 is attached has a small diameter and the original side 152 on which the grip 3 is disposed has a large diameter. The taper part 153 which expands gradually from the original side 152 is provided. The shape of the cored bar 150 is set so that the final shape of the final shaft can be formed in consideration of the thickness of the reinforcing fiber synthetic resin layer.
Note that some taper portions have the steep taper portion ST and the taper portions T1 and T2 (see FIG. 4) as described above, but FIG. 5 (a) does not have the plurality of taper portions. This is an example.

As shown in FIG. 5B, the reinforcing layer 160 is a narrow-width straight layer that reinforces the front side 151 to which the head 2 is attached, and is laminated and wound around the cored bar 150.
The head 2 has the highest speed when the golf club 1 is swung, and the load on the shaft 100 in the vicinity thereof becomes high. For this reason, the reinforcing layer 160 is used to locally reinforce the vicinity of the front side 151 in order to prevent damage even if the vicinity of the head is greatly bent during the swing.

  As shown in FIG. 5C, the bias layer 161 has a wider shape on the original side 152 depending on the taper shape of the shaft 100, and is laminated and wound over the entire length of the shaft 100. In this embodiment, two bias layers 161 and 161 in which the orientations of the reinforcing fibers are different from each other are laminated and wound in order from the above-described reinforcing layer 160. Therefore, the orientations of the reinforcing fibers of the two bias layers 161 and 161 are crossed. Further, as shown in FIG. 5C, the two bias layers 161 and 161 are laminated and wound while being shifted in the circumferential direction, thereby eliminating the overlap at the end portion of the prepreg and becoming an uneven thickness state. To prevent that.

As shown in FIG. 5D, the front side circumferential layer 162 is wider than the reinforcing layer 160, and the circumferential layer is laminated and wound so as to cover the front side 151. As described above, when the player swings the golf club, the front side 151 generates large loads in various directions (tensile, torsion, bending, etc.) by the head 2 at the farthest point of the swing path. . In this embodiment, since the front side circumferential layer 162 is laminated and wound only in a necessary portion as described above, ultimate weight reduction, strength improvement, and stabilization can be achieved.
Further, since the front-side circumferential layer 162 is wound between the bias layer 161 and a first straight layer 163 (see FIG. 5E) described later, the straight layer is substantially concentrated on the outer layer side, Crushing strength can be improved while maximizing bending rigidity.

  As shown in FIG. 5 (e), the first straight layer 163 has a wider shape on the original side 152 depending on the taper shape of the shaft 100, and is laminated and wound over the entire length of the shaft 100. Yes. In this embodiment, the two first straight layers 163 and 163 are laminated and wound in order from above the bias layer 161 and the front side circumferential layer 162.

  The bias layer 161, the second straight layer 165 described later, and the first straight layer 163 form an intermediate portion 130 of the shaft 100. With this configuration, the intermediate portion 130 of the shaft 100 can allow expansion and contraction of the reinforcing fibers and deformation of the shaft cross section with respect to bending stress, so that the kick point KP can be relatively easily moved from the front portion to the intermediate portion and the kick point KP. The golf club can be made into a golf club that is easy to swing because it can be sufficiently bent (bend) and sticky.

As shown in FIG. 5 (f), the former-side circumferential layer 164 has a circumferential layer laminated and wound from above the first straight layer 163 so as to cover the former side 152. The former side 152 is a portion corresponding to the grip 3 and is a portion where the player can strongly grip the golf club 1 during the swing.
With such a configuration, even if an abnormal crushing load is applied to the grip 3 during use, the damage can be prevented, so that the strength can be improved and stabilized. Since the circumferential layer is wound only on necessary portions, the ultimate weight reduction, strength improvement, and stabilization can be achieved.

The former side circumferential direction layer 164 is laminated and wound on the inner circumferential side adjacent to the second straight layer (see FIG. 5G) to be laminated and wound on the outermost periphery of the shaft 100 described later.
The end surface of the front side 151 in the axis X direction of the former side circumferential layer 164 is preferably formed in an inclined shape. This is to avoid the shaft 100 having a sharp intensity distribution.
With this configuration, it is possible to avoid the grip 3 attached later and the original circumferential layer 164 from coming into contact with each other, preventing the meandering of the fibers in the circumferential layer and the cutting of the fibers during surface polishing, and reducing the amount of fibers The maximum squeezing reinforcement effect can be obtained. Therefore, the golf club can be reduced in weight and strength required for each part of one shaft.

  As shown in FIG. 5G, the second straight layer 165 has a wider shape on the original side 152 depending on the taper shape of the shaft 100, and the first straight layer 163 extends over the entire length of the shaft 100. And the original side circumferential direction layer 164 is laminated and wound. Since the function of the second straight layer 165 is the same as that of the first straight layer 163 described above, description thereof is omitted.

As shown in FIG. 5 (h), the reinforcing layer 166 is a narrow-width straight layer that reinforces the original side 152 on which the grip 3 is provided, and is laminated and wound from above the second straight layer 165. .
Unlike the intermediate portion 130, the grip 3 is subjected to a crushing load when the golf club 1 is swung as described above. Local reinforcement is made for such a high load.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 6 shows a laminated configuration, and shows a prepreg cut shape applied to the bias layer, the straight layer, the front side circumferential layer, and the original side circumferential layer. In addition, about the structure which overlaps with 1st Embodiment, it abbreviate | omits and demonstrates a different part. In the following description, FIG. 1 is referred to as appropriate.

The shaft of this embodiment is produced by a sheet winding method using these prepregs, and is sequentially viewed from the inner periphery side in the order of the prepregs cut as shown in FIGS. 6 (b) to (i). A 6 (a) cored bar 250 is wound and laminated. Then, the synthetic resin is cured by heating and pressurizing and integrally molded, and then the cored bar 250 is pulled out to mold the shaft.
In addition, the thin line in the figure of FIG.6 (b)-(i) has shown the orientation of the reinforced fiber similarly to FIG.

As shown in FIG. 6A, the core metal 250 has a diameter of the front side 251 such that the front side 251 to which the head 2 is attached has a small diameter and the original side 252 on which the grip 3 is disposed has a large diameter. The first gradual taper portion MT1, the second gradual taper portion MT2, the steep taper portion ST1, the third gradual taper portion MT3, and the straight portion ET are sequentially provided from the front side 251. The shape of the cored bar 250 is set so that the final shape of the final shaft can be formed in consideration of the thickness of the reinforcing fiber synthetic resin layer.
Here, in the respective taper portions, when the shaft is formed, the above-described taper portions TP1 and TP2 correspond to the second gentle taper portion MT2 and the third gentle taper portion MT3, respectively, and the steep taper portion ST is This corresponds to the steep taper portion ST1 (see also FIG. 4).

  As can be seen by comparing FIGS. 5 and 6, the reinforcing layer 160 of FIGS. 5B and 6B, the front circumferential layer 162 of FIGS. 5D and 6D, FIG. Since the reinforcing layer 166 in (h) and FIG. 6 (i) is a part having the same shape and the same function, the description thereof is omitted.

As shown in FIG. 6C, the bias layer 261 is arranged on the original side 152 in accordance with the taper shape of the shaft 200 in accordance with the second gentle taper portion MT2, the steep taper portion ST1, and the third gentle taper portion MT3. Has a wide shape and is laminated and wound over the entire length of the shaft.
Since the reinforcing layer 160 is laminated and wound on the inner peripheral side for the first gentle taper portion MT1, and the straight portion ET has a small change from the third gentle taper portion MT3, FIG. Then, although the shape is not changed, these shapes and the like may be considered in actual manufacturing.

  In this example, similarly to the first embodiment, two bias layers 261 and 261 having different reinforcing fiber orientations are stacked and wound in order from the top of the reinforcing layer 160 described above. Therefore, the orientations of the reinforcing fibers of the two bias layers 261 and 261 are crossed. Further, as shown in FIG. 6C, the two bias layers 261 and 261 are stacked and wound while being shifted in the circumferential direction, thereby eliminating the overlap at the end portion of the prepreg and becoming an uneven thickness state. To prevent that.

  As shown in FIG. 6E, the adjustment straight layer 267 has an overlapping portion E that partially overlaps the original end surface in the axis X direction of the front side circumferential layer 162, and the bias side 261 and the front side circumference. The directional layer 162 is laminated and wound from above. The adjustment straight layer 267 is provided corresponding to the shape of the steep taper part ST1, and for example, by making a cut D shown by a broken line, meandering of the reinforcing fibers can be prevented.

As shown in FIG. 5 (f), the first straight layer 263 is formed on the original side 152 in accordance with the second gentle taper portion MT2, the steep taper portion ST1, and the third gentle taper portion MT3 according to the taper shape of the shaft. It has a wider shape, and is laminated and wound from above the front-side circumferential layer 162 and the adjustment straight layer 267 over the entire length of the shaft.
For the first gentle taper portion MT1, the reinforcing layer 160 is laminated and wound on the inner peripheral side, and for the straight portion ET, the change from the third gentle taper portion MT3 is small. However, in actual manufacturing, these shapes and the like may be taken into consideration.
Note that the notch D in the adjustment straight layer 267 (FIG. 6E) can also be applied to the first straight layer 263.

As shown in FIG. 6G, the former-side circumferential layer 264 is formed on the inner peripheral side adjacent to the second straight layer (see FIG. 6H) that is laminated and wound on the outermost periphery of the shaft described later. Laminated and wound.
Unlike the first embodiment, the end surface of the front side 251 in the axis X direction of the original side circumferential layer 264 is formed in a straight line. This is because the layer thickness is adjusted by other layers, and may be formed in an inclined shape as in the first embodiment.
With such a configuration, it is possible to avoid contact between the grip 3 to be attached later and the original circumferential layer 264, and to prevent meandering of the fibers in the circumferential layer and cutting of the fibers during surface polishing, and a small amount of fiber. The maximum squeezing reinforcement effect can be obtained. Therefore, the golf club can be reduced in weight and strength required for each part of one shaft.

  As shown in FIG. 6 (h), the second straight layer 265 is formed on the original side 152 in accordance with the second gentle taper portion MT2, the steep taper portion ST1, and the third gentle taper portion MT3 according to the taper shape of the shaft. It has a wider shape, and is laminated and wound from above the first straight layer 163 and the original circumferential layer 164 over the entire length of the shaft. Since the function of the second straight layer is the same as that of the first straight layer 163 described above, description thereof is omitted.

  The preferred embodiments have been described above. However, the present invention is not limited to the above-described embodiments, and appropriate modifications can be made without departing from the scope of the present invention.

1 is an external side view of a golf club provided with a shaft according to a first embodiment of the present invention. FIG. 2 is an enlarged partial cross-sectional view of the front side shown in a range A surrounded by a one-dot chain line in FIG. 1. FIG. 3 is an enlarged partial cross-sectional view on the original side shown in a range B surrounded by a one-dot chain line in FIG. 1. It is an expanded partial sectional view of the intermediate part shown in the range C enclosed with the dashed-dotted line of FIG. 1 shows a prepreg laminated structure of a shaft according to a first embodiment of the present invention, where (a) is a cored bar, (b) to (h) are bias layers, straight layers, front side circumferential layers, and original side circumferential layers. The cutting shape of the prepreg applied to is shown. The prepreg lamination structure of the shaft which concerns on 2nd Embodiment of this invention is represented, (a) is a metal core, (b)-(i) is a bias layer, a straight layer, a front side circumferential direction layer, a former side circumferential direction layer. The cutting shape of the prepreg applied to is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Golf club 2 Head 3 Grip 100 Shaft 110 Front side 111 Bias layer 112,113,122 Straight layer 114 Front side circumferential layer 120 Original side 123 Original side circumferential direction layer 130 Middle part 150 Core metal KP Kick point ST Steep taper part T1 , T2 Taper

Claims (4)

A shaft comprising a plurality of fiber-reinforced synthetic resin layers, each having a front side on which a club head is provided at the front end and a base side on which a grip is disposed, and having an outer diameter gradually increased from the front side to the base side. A golf club comprising
A bias layer in which the reinforcing fibers of the fiber-reinforced synthetic resin layer are oriented at an inclination angle of ± 35 degrees or more and ± 55 degrees or less with respect to the axial direction over the entire length of the shaft, and the reinforcing fibers of the fiber-reinforced synthetic resin layer Has a straight layer oriented in the axial direction,
The front side and the former side each further have a front side circumferential layer and a former side circumferential layer in which the reinforcing fibers are oriented in the circumferential direction,
The axial length of the front-side circumferential layer is 20% or more and 50% or less of the total length of the shaft from the tip portion to the original side,
The length in the axial direction of the original side circumferential layer is at least the length of the grip,
A golf club shaft, wherein an intermediate portion sandwiched between the front-side circumferential layer and the original-side circumferential layer has a length exceeding 30% of the total length. A steep taper portion in which the outer diameter of the shaft is reduced in a conical shape from the original side to the front side at the intermediate portion and closer to the original side from the kick point;
The taper of the steep taper portion is larger than that of the other taper portion when another taper portion is provided on the front side and / or the original side in the axial direction of the steep taper portion. 2. A shaft of a golf club according to 1. The front side includes the bias layer on at least the inner peripheral side, the straight layer on at least the outer peripheral side, the bias layer and the straight layer, or the front side circumferential direction between the plurality of straight layers. A layer, and
The original side comprises the bias layer on the inner peripheral side, the straight layer on the outer peripheral side, and the original circumferential direction layer adjacent to the inner peripheral side of the outermost straight layer. The golf club shaft according to claim 1 or 2.   The front-side circumferential layer and the original-side circumferential layer are each made of a prepreg sheet that is thinner than the bias layer and the straight layer and has a greater amount of synthetic resin impregnation than the bias layer and the straight layer. The golf club shaft according to any one of claims 1 to 3, wherein the golf club shaft is formed by being wound in layers or less than two layers.

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