JP5975422B2 - Shaft with conductive structure - Google Patents

Description

  The present invention relates to a shaft having a conductive structure, and more particularly to a shaft to which a sensor can be attached.

  In golf clubs, it is known that the bending of a shaft affects performance such as flight distance. The shaft bending can be evaluated in a static state, but the dynamic behavior of the shaft during the swing does not necessarily match the result of the evaluation in the static state. Therefore, strain gauges are attached to any two points on the shaft to obtain information on dynamic behavior such as various deformations of the shaft during the swing. It has been proposed to evaluate the behavior (Patent Document 1). Further, the evaluation of the dynamic behavior of the shaft is required not only for golf clubs but also for tools having rod-like members (shafts) such as fishing rods, tennis rackets, or baseball bats.

JP 2003-102886 A

  However, in order to evaluate the dynamic behavior of the shaft, if the strain gauge attached to the shaft and the strain measurement device are connected by wiring, the dynamic behavior of the shaft may change depending on the weight of the wiring. . Therefore, it has been difficult to accurately evaluate the dynamic behavior of the shaft itself such as bending.

  The present invention has been made to solve the above-described conventional problems, and suppresses a change in the dynamic behavior of the shaft due to the attachment of a sensor to the shaft, thereby enabling more accurate dynamic behavior of the shaft itself. The purpose is to provide technology to evaluate.

In order to attain at least part of the above problems, the shaft of the present invention is a shaft sensor is configured to be mounted, a conductive structure that is responsible for the mechanical strength of the shaft, the conductive A conductive coating film formed on a part of the outer surface of the conductive structure, and the sensor is attached to the outer peripheral portion of the shaft, arranged along the longitudinal direction of the shaft, and connected to the sensor A part of the plurality of lines includes the conductive structure portion and the conductive coating film . According to this configuration, wiring corresponding to some of the plurality of lines can be omitted from the wiring provided in addition to the shaft. As a result, the weight of the wiring can be reduced and the dynamic behavior of the shaft can be prevented from changing due to the weight of the wiring, so that the dynamic behavior of the shaft itself can be more accurately evaluated. .
In this configuration, a part of the plurality of lines includes a conductive coating film formed on a part of the outer surface of the conductive structure part, and the sensor is attached to the outer peripheral part of the shaft. For this reason, it becomes easier to attach the sensor to the shaft, and it becomes easier to form a part of the track.

  The part of the lines may be a reference potential line connected to a reference potential point. According to this configuration, since the conductive structure portion is used as a reference potential line that is commonly used for a plurality of sensors, it is easier to use the plurality of sensors.

Explanatory drawing which shows the structure of the golf club using this invention. The circuit diagram of the detection circuit which detects the deformation amount of a strain gauge in a strain measuring device. Explanatory drawing which shows a mode that a strain gauge is attached to a shaft. Explanatory drawing which shows the other aspect which attaches a strain gauge to a shaft. Explanatory drawing which shows the structure of the shaft in 2nd Example. Explanatory drawing which shows the structure of the shaft of the aspect different from FIG. 5 in 2nd Example. Explanatory drawing which shows the structure of the shaft in 3rd Example. Explanatory drawing which shows a mode that the electrical resistance of a CFRP layer is measured.

A. First embodiment:
FIG. 1 is an explanatory diagram showing a configuration of a golf club 10 using the present invention. The golf club 10 has a head 11, a grip 12, and a shaft 13 to which the head 11 and the grip 12 are attached at both ends. The shaft 13 is a tapered hollow member that narrows from the grip 12 toward the head 11. As will be described in detail later, the shaft 13 includes a carbon fiber reinforced resin (CFRP) layer in which a carbon fiber layer is impregnated with a matrix resin and cured, and a coating film of an insulating paint ( Insulating film). A plurality of strain gauges 21 for measuring strain at each position of the shaft 13 are fixed to the golf club 10 with an adhesive, an adhesive tape, or the like. The wiring member 22 wound around the shaft 13 is formed of a flexible printed board, and one end thereof is introduced into the shaft 13 on the grip 12 side. Each terminal of the strain gauge 21 is a strain measurement provided inside the shaft 13 at the position of the grip 12 via a plurality of conductive wires (not shown) formed on the wiring member 22 and a conductive CFRP layer. Connected to a device (not shown). The strain measuring device detects the deformation amount of the strain gauge 21 from the change in the resistance value of the strain gauge 21. The detected deformation amount of the strain gauge 21 is wirelessly transmitted from the strain measuring device to an external device. Thereby, it becomes possible to evaluate the dynamic deformation state of the shaft 13 when a user such as a bend swings. Note that the transmission of the deformation amount from the strain measurement device to the external device may be performed by wire, or the strain measurement device may be installed outside. In these cases, necessary wiring is drawn from the grip 12 side.

  FIG. 2 is a circuit diagram of a detection circuit 30 that detects the deformation amount of the strain gauge 21 in the strain measurement apparatus. The detection circuit 30 includes three resistors R1 to R3, a constant voltage source 31, and a voltage detector 32. The gauge resistance Rg of the strain gauge 21 is connected to the detection circuit 30 by three lines LA to LC. Lines LA and LB extending from both ends of the gauge resistor Rg are connected to ends of the resistors R1 and R3 opposite to the resistor R2, respectively, and the gauge resistor Rg and the three resistors R1 to R3 form a closed circuit. The voltage detector 32 is connected to the connection point between the resistor R1 and the gauge resistor Rg and the connection point between the two resistors R2 and R3 on the detection circuit 30 side. The constant voltage source 31 is connected to the connection point of the two resistors R1 and R2 on the detection circuit 30 side, and is connected to the connection point of the resistor R3 and the gauge resistor Rg on the strain gauge 21 side. Thereby, the strain gauge 21, the lines LA to LC, the constant voltage source 31, and the voltage detector 32 constitute a bridge. In the first embodiment, conductors formed on the wiring member 22 are used as the lines LA and LB constituting the closed circuit in the bridge. This suppresses the resistance of the lines LA and LB from affecting the detection result of the deformation amount. On the other hand, the CFRP layer of the shaft 13 is used as the line LC connected to the constant voltage source 31. As described above, since the strain measuring device is provided inside the shaft 13 at the position of the grip 12, the lines LA to LC connecting the strain gauge 21 and the strain measuring device are arranged in the longitudinal direction of the shaft 13 ( That is, it is provided in the direction from the head 11 side toward the grip 12 side.

  FIG. 3 is an explanatory diagram showing a state in which the strain gauge 21 is attached to the shaft 13. FIG. 3A shows a cross section of the shaft 13 to which the strain gauge 21 is attached. As shown in FIG. 3A, the shaft 13 has a CFRP layer 131 and an insulating coating film 132 formed on the outer surface of the CFRP layer 131. When attaching the strain gauge 21, first, as shown in FIG. 3B, a part of the insulating coating film 132 is peeled off to provide an opening 133. Thus, even if a part of the insulating coating film 132 is peeled off and the opening 133 is provided, the CFRP layer 131 (structure part) responsible for the mechanical strength is in the original state of the shaft 13 shown in FIG. Are the same. Therefore, the influence on the strength of the shaft 13 by providing the opening 133 can be ignored. In the first embodiment, a part of the insulating coating film 132 is peeled off to form the opening 133, but a shaft provided with the opening 133 in advance may be prepared.

  Next, after fixing the strain gauge 21 with an adhesive, an adhesive tape or the like, as shown in FIG. 3C, the terminals of the strain gauge 21 connected to the constant voltage source 31 (FIG. 2) and the CFRP layer 131 are connected. The connection member 23 is connected through the opening 133. Further, the other terminal of the strain gauge 21 and the wiring member 22 are connected by the connecting member 24. Thereby, the strain gauge 21 and the detection circuit 30 (FIG. 2) include the lines LA and LB constituted by the connection member 24 and the wiring member 22, and the line LC constituted by the connection member 23 and the CFRP layer 131. Connected. As the connecting member 23 that connects the terminal of the strain gauge 21 and the CFRP layer 131, for example, a conductive resin can be used. Moreover, as the connection member 24 which connects the terminal of the strain gauge 21 and the wiring member 22, for example, a conductive resin, a copper wire, or the like can be used. As shown in FIG. 3C, when the strain gauge 21 is attached to the outer peripheral side of the shaft 13, a solid shaft can be used instead of the hollow shaft 13.

  FIG. 4 is an explanatory view showing another aspect of attaching the strain gauge 21 to the shaft 13. In the example of FIG. 4, the strain gauge 21 is attached to the inside of the shaft 13. Although not shown, the wiring member 22 is connected to a strain measuring device provided on the grip 12 side through the inside of the shaft 13. As shown in FIG. 4, since the conductive CFRP layer 131 is exposed on the inner surface of the shaft 13, the strain gauge 21 is fixed to the CFRP layer 131 with the insulating resin layer 25 interposed therebetween. 3, the strain gauge 21 and the detection circuit 30 (FIG. 2) are connected by connecting the terminals of the strain gauge 21 to the CFRP layer 131 and the wiring member 22. In addition, peeling off a part of insulating coating film 132 and providing the opening part 133 is abbreviate | omitted. In this case, since the external shape of the shaft 13 is the same as the original state, the influence of the air resistance of the strain gauge 21 and the wiring member 22 on the deformation state of the shaft 13 is reduced, and the deformation state of the shaft 13 is more accurately determined. It becomes possible to evaluate. However, it is preferable to attach the strain gauge 21 to the outer peripheral portion of the shaft 13 in that the strain gauge 21 can be easily attached.

  As described above, in the first embodiment, the CFRP layer 131 is used as the line LC connected to the constant voltage source 31 among the lines LA to LC connecting the strain gauge 21 and the detection circuit 30 (FIG. 2). Therefore, the conducting wire for use in the line LC can be omitted from the wiring member 22, and the number of conducting wires formed on the wiring member 22 can be reduced. Therefore, the wiring member 22 can be thinned and its weight can be reduced. Therefore, the influence of the weight of the wiring member 22 on the deformation state of the shaft 13 can be reduced, and the deformation state of the shaft 13 can be more accurately evaluated. Is possible. Further, by making the wiring member 22 thinner, stress applied to the wiring member 22 itself at the time of swing is reduced, so that it is easy to suppress the occurrence of troubles such as disconnection of the conductive wire formed on the wiring member 22.

  In the first embodiment, the CFRP layer 131 is used for the line LC connected to the constant voltage source 31, but other configurations are possible. For example, it is possible to replace the voltage detector 32 and the constant voltage source 31 and use the CFRP layer 131 for a line connected to the voltage detector 32. However, since the potential of each terminal of the voltage detector 32 changes depending on the state of each strain gauge 21, it is not easy to use the plurality of strain gauges 21 and the detection circuit 30. On the other hand, both ends of the constant voltage source 31 have a constant potential. Therefore, the CFRP layer 131 is connected to one end (a reference potential point or a ground) of the constant voltage source 31 serving as a potential reference in that it becomes easier to use the plurality of strain gauges 21 and the detection circuit 30. It is preferably used for the line LC (reference potential line). When the strain gauge 21 is attached to the inside of the shaft 13 and the CFRP layer 131 is used for the line LC connected to one end of the constant voltage source 31, the other lines LA and LB are connected to the reference potential of the shaft 13. Arranged inside. Therefore, noise induced in the lines LA and LB can be reduced.

B. Second embodiment:
FIG. 5 is an explanatory diagram showing the configuration of the shaft 13a in the second embodiment. FIG. 5A is a perspective view of the shaft 13a viewed from the grip 12 side, FIG. 5B is a cross-sectional view of the shaft 13a on the AA plane, and FIG. It is sectional drawing of the shaft 13a in a B surface. As shown in FIG. 5, in the shaft 13a of the second embodiment, a substantially circular opening 133a is provided in advance in an insulating coating film 132a formed on the outer surface of the CFRP layer 131, and the position of the opening 133a. In FIG. 1, a conductive paint film (conductive film) 134 a is formed on the outer surface of the CFRP layer 131. Other points are the same as in the first embodiment. Thus, by forming the conductive coating film 134a on the outer surface of the CFRP layer 131, the terminals of the strain gauge 21 are connected to the CFRP layer 131 through the conductive coating film 134a. In this case, the conductive coating film 134a is included in the line LC (FIG. 2).

  FIG. 6 is an explanatory view showing the configuration of the shaft 13b in a mode different from FIG. 5 in the second embodiment. 6A is a perspective view of the shaft 13b viewed from the grip 12 side, FIG. 6B is a cross-sectional view of the shaft 13b on the AA plane, and FIG. It is sectional drawing of the shaft 13b in a B surface. The shaft 13b shown in FIG. 6 is different from the shaft 13a shown in FIG. 5 in that the opening 133b provided in the insulating coating film 132b has an annular shape. Other points are the same as the shaft 13a shown in FIG. In the shaft 13b of FIG. 6, the opening 133b and the conductive coating film 134b are formed symmetrically with respect to the axis of the shaft 13b, so that the shaft 13b conforms to the rules of golf. Therefore, if the strain gauge 21, the wiring member 22, and the strain measuring device are detachable, the deformation state of the shaft 13b itself used in the game can be measured.

  In the second embodiment, conductive coatings 134 a and 134 b are formed on the outer surface of the CFRP layer 131. In this case, if the conductive coating films 134a and 134b are formed of a solderable resin (see, for example, Japanese Patent Laid-Open No. 10-31912), the terminals of the strain gauge 21 (FIG. 3) are connected to the conductive coating films 134a and 134b. Can be soldered to Further, even when the carbon fiber content is increased or the like, the adhesiveness of the CFRP layer 131 is lowered, and the adhesiveness to the conductive coating films 134a and 134b is reduced even when the connecting member 24 is peeled off relatively easily. Can be high enough. Further, the terminals of the strain gauge 21 are projected from the surfaces of the strain gauges 21 on the shafts 13a, 13b side, and the strain gauges 21 are pressed against the shafts 13a, 13b so that the terminals come into contact with the conductive coatings 134a, 134b. Then, the terminal of the strain gauge 21 can be connected to the conductive coating films 134a and 134b. Thus, according to the second embodiment, by forming the conductive coatings 134a and 134b on the outer surface of the CFRP layer 131, the terminals of the strain gauge 21 are electrically connected to the CFRP layer 131, and the line LC is connected. It is easier to form.

C. Third embodiment:
FIG. 7 is an explanatory diagram showing the configuration of the shafts 13c and 13d in the third embodiment. 7A and 7B are cross-sectional views of the shaft 13c on the AA plane (see FIG. 5) and the BB plane. 7C and 7D are cross-sectional views of the shaft 13d on the AA plane (see FIG. 5) and the BB plane. As shown in FIG. 7, in the third embodiment, conductive coating films 134c and 134d formed on the outer surface of the CFRP layer 131 at the positions of the openings 133a and 133b protrude from the insulating coating films 132a and 132b. Thus, the shafts 13a and 13b (FIGS. 5 and 6) of the second embodiment are different. The other points are the same as the shafts 13a and 13b of the second embodiment. Thus, by making the conductive coating films 134 c and 134 d protrude, it becomes easier to connect the terminals of the strain gauge 21 to the CFRP layer 131. Further, in the shaft 13d shown in FIGS. 7C and 7D, the outermost periphery of the conductive coating film 134d is located outside the insulating coating film 132b. Therefore, when the shaft 13d rolls, etc., it can suppress that the insulating coating film 132b is damaged.

D. Variations:
The present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

D1. Modification 1:
In each of the above-described embodiments, the CFRP layer 131 formed of carbon fiber reinforced resin is used as the structural portion responsible for the mechanical strength of the shafts 13 to 13d. It is also possible to form with other materials. The structure portion can be formed of, for example, a resin in which carbon nanotubes are dispersed, a resin in which metal fibers are dispersed, or the like.

D2. Modification 2:
In each of the above embodiments, the dynamic deformation state of the shafts 13 to 13d is evaluated by attaching the strain gauges 21 to the shafts 13 to 13d. However, various sensors are attached to the shafts 13 to 13d, and the shaft 13 It is also possible to evaluate the dynamic behavior of ˜13d. For example, the dynamic behavior of the shafts 13 to 13d can be evaluated by attaching an angle sensor or an acceleration sensor to the shafts 13 to 13d.

  Furthermore, it is possible to use the CFRP layer 131 to evaluate the state of the shafts 13 to 13d without using a sensor. For example, as shown in FIG. 8, two measurement terminals 42 connected to both ends of the battery 41 and two measurement terminals 44 connected to both ends of the voltmeter 43 have two different conductivity. It is possible to measure the electrical resistance of the CFRP layer 131 between the two conductive coatings 134d by contacting the coating 134d (referred to as a four-terminal method). In this case, the CFRP layer 131 functions as a part of a circuit for evaluating the state of the shaft. Normally, when damage such as cracks occurs in the CFRP layer 131, the electrical resistance of the CFRP layer 131 increases in the damaged region. Therefore, as shown in FIG. 8, by measuring the electrical resistance of the CFRP layer 131, it is possible to evaluate whether or not the shaft 13d is damaged and where it is damaged. it can. Also, when damage is detected, a warning can be issued by a lamp such as an LED or a buzzer. FIG. 8 shows an example of the shaft 13d in which the annular conductive coating film 134d protrudes from the insulating coating film 132b. The electrical resistance of the CFRP layer 131 is measured on the insulating coating films 132 to 132b. If the openings 133 to 133b are provided, the shafts having various shapes described in the above embodiments can be used. In the example of FIG. 8, the electrical resistance of the CFRP layer 131 is measured by the 4-terminal method, but the electrical resistance of the CFRP layer 131 may be measured by other methods such as the 2-terminal method. However, it is preferable to measure the electrical resistance of the CFRP layer 131 by the four-terminal method in that the measurement accuracy of the electrical resistance can be increased.

D3. Modification 3:
In each of the above embodiments, the present invention is applied to the shafts 13 to 13d of the golf club 10. However, the present invention is applied to various shafts (rod-like members) in addition to the shafts 13 to 13d of the golf club 10. Can do. The present invention can be applied to, for example, a rod member in a fishing rod, a tennis racket, or a baseball bat.

  DESCRIPTION OF SYMBOLS 10 ... Golf club, 11 ... Head, 12 ... Grip, 13 ... Shaft, 13a, 13b, 13c, 13d ... Shaft, 21 ... Strain gauge, 22 ... Wiring member, 23 ... Connection member, 24 ... Connection member, 25 ... Insulation Resin layer, 30 ... detection circuit, 31 ... constant voltage source, 32 ... voltage detector, 41 ... battery, 42 ... measurement terminal, 43 ... voltmeter, 44 ... measurement terminal, 131 ... CFRP layer, 132, 132a 132b ... Insulating coating, 133, 133a, 133b ... opening, 134a, 134b, 134c, 134d ... conductive coating, LA, LB, LC ... line, R1, R2, R3 ... resistance, Rg ... gauge resistance

Claims (2)

A shaft sensor is configured to be attached,
A conductive structure responsible for the mechanical strength of the shaft;
A conductive coating formed on a part of the outer surface of the conductive structure;
With
The sensor is attached to the outer periphery of the shaft,
A part of the plurality of lines arranged along the longitudinal direction of the shaft and connected to the sensor includes the conductive structure portion and the conductive coating film .
shaft. The part of the lines is a reference potential line connected to a reference potential point.
The shaft according to claim 1.

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