JP2002028263A - Racket frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a racket frame which can achieve a good repulsion characteristic and controllability by reducing a impact to the hand of a player. SOLUTION: The impact point P is set near a region of a node 8a of vibration existing on the top side of the frame and simultaneously the width of a ball hitting part 3 is maximized in the region described above. Simultaneously the position of an immobile point Q when a ball 7 is hit in the impact point P position is so set as to exist within a range of 50 to 80 mm from the terminal of a grip 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a racket frame for reducing vibration of a racket frame generated when hitting a ball, improving resilience characteristics, and improving control performance.

[0002]

2. Description of the Related Art As shown in FIG. 4, when considering the movement of a racket frame 21 when hitting a ball 25, when the racket frame 21 receives a striking force F in the X-axis direction at a striking point P at the time of striking. Each point of the racket frame 21 exhibits a parallel movement of the center of gravity G and a rotational movement around the center of gravity G. At this time, there are momentarily momentary points that remain stationary during the movement. This point is the fixed point Q at the time of hitting, which is called the center of hitting.

Such a fixed point Q is determined by the distance h from the strike point P of the ball 25 to the center of gravity G, the mass m of the racket frame itself, and the moment of inertia I around the center of gravity G.
It is derived by various elements consisting of G,
Generally, the distance hx from the fixed point Q to the hit point P
Is obtained by the following equation (1). hx = h + IG / (m · h) Equation (1)

[0004] That is, the ball 25 is
When the ball is hit, the position of the fixed point Q fluctuates according to the difference in the point at which the ball 25 is hit (hit point P). Generally, the player frequently plays the game while gripping the center of the grip portion 23 within a region s of 50 mm to 80 mm from the end portion 24 of the grip portion 23 of the racket frame 21. Therefore, for example, as shown in FIG. 4, when the fixed point Q hits the ball 25 at a suitable hitting point P such that the fixed point Q is located in the region s of the grip portion 23 gripped by the player, Grip part 23
In the area s, the movement is momentarily stopped, so that the impact (initial vibration at the time of hitting) felt by the player's hand is reduced, and the energy loss at the time of hitting is suppressed. On the other hand, if the hitting point deviates from the above-described preferable hitting point, the fixed point Q shifts to a position outside the area s held by the player, and the player grips at the time of hitting. In the region s, the parallel movement of the center of gravity G and the rotational movement around the center of gravity G as described above are exhibited, so that the hand gripping the grip portion 23 shakes, and the energy at the time of impact is significantly consumed. In addition, the control performance at the time of hitting is reduced.

The hit point P when hitting the ball 25 varies depending on the player layer.
That is, on average, in general, for a beginner or a weak player, the position of the hitting point P when hitting the ball 25 is more than the middle point of the longitudinal axis of the hitting portion 22 in the grip portion 23.
In the intermediate level, the area is closer to the middle point, and in the advanced level, the area is closer to the top than the middle point.

Therefore, in recent years, a racket frame has been designed in consideration of such a situation in consideration of a different hitting point position for each player layer. For example, in Japanese Patent No. 2828018, as shown in FIGS.
By hitting or hitting the hit point P when hitting the ball 36 in the face maximum width position 33 area where the resilience of the ball 36 is the best in the area 2, and the position of the center of gravity of the racket frame 31, Ball of time 36
At the same time, it is proposed that the face maximum width position 33 is designed to be adapted to a region where the hitting frequency of each player layer such as a beginner or an advanced player is high.

That is, the shape of the face surface 32 of the racket frame 31 is such that the face maximum width position 33 is in the midpoint area 34 of the face length N (elliptical shape), and the face maximum width position 33 is the face length N. A mode in which the face is located closer to the grip portion 35 than the midpoint 34 (a shape in which the face is expanded on the grip portion 35 side), and a face maximum width position 33
Is located on the face top side from the midpoint 34 of the face length N (the face is bulged on the top side)
In the case of a beginner or a weak player, the hit point is more than the center of the face surface 32 in the grip portion 35.
As shown in FIG. 6, the face maximum width position 33 is positioned closer to the grip portion 35 than the midpoint 34 of the face length N in order to adapt to this. In FIG. 7, since the hit point is biased toward the top side from the center of the face surface 32, the face maximum width position 33 is shifted to the top side from the midpoint 34 of the face length N as shown in FIG. Is located.

[0008]

In this type of proposal, the shape of the face surface 32 (the face maximum width position 33) is adjusted according to the different hitting positions for each player layer. For the layer, good rebound characteristics can be expected when hit.

However, with this type of racket frame 31, when hitting the ball 36 as described above,
No consideration is given to reducing the impact force acting on the player's hand, and in particular, it is not considered that the fixed point causes a shift due to the difference in the position of the hitting point P,
With the shift of the hitting point P, the position of the fixed point occurs at a position apart from the area of the grip portion gripped by the player, and a large impact force is easily transmitted to the player's hand. .

Further, as a result of various studies by the present inventors, the position of the hit point P at the time of hitting the ball is far from the region where the node 37 of the out-of-plane primary bending vibration M of the racket frame 31 is located. It has been found that when separated, the vibration generated at the time of hitting is amplified, and the energy at the time of hitting is consumed by the amplified vibration, so that it is difficult to exhibit good resilience characteristics at the time of hitting. Therefore, in order to sufficiently satisfy the rebound characteristics of the racket frame, it is preferable to provide the face maximum width position near the region where the node of the out-of-plane primary bending vibration M of the racket frame is located, and set the hitting point P in the region. . That is, it has been found that shifting the face maximum width position to the frame top side and positioning the impact point P closer to the top portion can be expected to provide the best resilience characteristics. However, if the racket frame is designed with the sole purpose of improving the resilience characteristics, the fixed point of the racket frame will be displaced from the area of the grip portion gripped by the player, and the player will not be Therefore, it was found that it is necessary to limit the displacement of the immovable point while the striking point P is positioned closer to the top portion.

In view of the foregoing, the present invention has been made to provide a racket frame capable of reducing the impact transmitted to the player's hand when hitting and achieving good rebound characteristics and controllability. Aim.

[0012]

In order to achieve the above object, the present invention has the following arrangement. That is, in the racket frame according to the first aspect of the present invention, the maximum width position of the hitting portion in the direction orthogonal to the longitudinal axis of the racket frame is equal to the entire racket frame length L from the end of the grip portion.
And the fixed point position of the racket frame when the maximum width position region on the longitudinal axis of the racket frame is set as the ball hitting point is within the range of 0.71L to 0.83L. 50mm from the end of
It is characterized in that it is set within a range of 80 mm.

According to a second aspect of the present invention, there is provided the racket frame according to the first aspect, wherein a maximum width position of the hitting portion is provided near a region corresponding to a node of the out-of-plane primary bending vibration of the racket frame. It is characterized by being carried out.

According to a third aspect of the present invention, there is provided the racket frame according to the first or second aspect, wherein a total length L of the racket frame from the end of the grip portion of the racket frame is 0.3.
The mass body is provided in a range of 0 L to 0.50 L.

A fourth aspect of the present invention is the racket frame according to the first, second, or third aspect, wherein the mass of the racket frame before the gut is stretched is in a range of 200 g to 260 g. Things.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. That is, as shown in FIG. 1, the racket frame 1 of the present embodiment has a hitting portion 3 on which a gut 2 is stretched to form a net surface, and a left and right 2 connecting the hitting portion 3 and the grip portion 4. The shaft portion 5 is formed integrally with a fiber reinforced resin.

As shown in FIG. 1, the out-of-plane primary bending vibration M generated when the racket frame 1 hits the ball 7 is
Near the top side of the racket frame 1 (from the end portion 6 of the grip portion 4 to the total racket frame length L of 0.83L or more).
0.92L) and near the grip portion 4 side (from the end portion 6 of the grip portion 4 to the total length L of the racket frame 0.1).
7L to 0.30L) and have nodes 8a and 8b,
The antinode 9 of the vibration is in a region between the nodes 8a and 8b. In the racket frame 1 of the present embodiment, the hitting point P is set in the vicinity of the region of the vibration node 8a located on the top portion side so as to obtain a good rebound characteristic at the time of hitting. The width of the portion 3 is configured to be maximum. That is, the maximum width W position of the hitting portion 3 in the direction orthogonal to the longitudinal axis y of the racket frame 1 is set within the range of 0.71 L to 0.83 L of the entire racket frame L from the end portion 6 of the grip portion 4. It is configured to be located.

At the same time, the racket frame 1 of this embodiment
In the above, the position of the fixed point Q when the ball is hit at the hit point P is set so as to be located within a range of 50 mm to 80 mm from the end portion 6 of the grip portion 4 normally held by the player, It is configured to suppress the impact acting on the player's hand when hitting.

In order to set the position of the fixed point Q with respect to the hitting point P within the above-described appropriate range, the outer shape, cross-sectional shape, wall thickness, type of material used, arrangement location of the racket frame 1 are set. It can be achieved by variously selecting / combining the above and taking measures for improving the linear density distribution on the longitudinal axis y of the racket frame 1.

That is, in the racket frame 1 of the present embodiment, the maximum width W of the hitting portion 3 is provided in a region where the node 8a of the out-of-plane primary bending vibration M of the racket frame 1 is located. The W position is located on the top portion side of the racket frame 1, and the hit point P is also near the top portion side. Therefore, in such a racket frame 1, as shown in FIG. 3, if the linear density distribution is not optimized, the position of the fixed point Q shifts to the top side with the shift of the hit point P. What happens. However, in this embodiment, the position of the fixed point Q with respect to the hit point P is
In order to set within the above-mentioned appropriate range, a line density distribution obtained by obtaining an optimum position of the center of gravity with respect to the hitting point P and an optimum moment of inertia around the position of the center of gravity was obtained. That is, as shown in FIG. 2, the racket frame of the present embodiment is designed by increasing the linear density within the range e of 0.30 L to 0.50 L of the entire racket frame L from the end portion 6 of the grip portion 4. You.

The rate of increasing the linear density varies depending on the outer shape, the mass and the like of the racket frame.
In general, it is preferable that the mass in the range e be in the range of 3% to 12% of the mass of the racket frame 1.

Further, as a specific means, as shown in FIG. 1, a means for disposing a mass body 10 of 9 g to 36 g in the range e is employed. The mass of the mass body 10 is 9 g
If the fixed point Q is smaller than the fixed range, the fixed point Q deviates from the suitable range in which the player grips the grip portion 4 to the distal end portion 6 side of the grip portion. A large impact is transmitted to the player's hand when hitting off the top.

The racket frame 1 of the present embodiment as described above.
In order to manufacture, for example, around a tube for internal pressure molding, a plurality of prepreg sheets for racket frame molding are laminated, and after arranging this in a cavity having a mold frame shape, In a normal manufacturing method of a racket frame made of fiber reinforced resin, for example, by injecting compressed air or the like and heating, the type and the amount of lamination of the prepreg sheet are adjusted, and the total length L of the racket frame is set at 0 from the end of the grip portion. A means for manufacturing a racket frame so that the linear density distribution as described above can be obtained by incorporating the mass body 10 and integrally curing and molding the mass body 10 in a region corresponding to a range e of 30L to 0.50L. Can be In addition to such a method, a method of obtaining the racket frame having the linear density distribution as described above by bonding the mass body 10 within the above-described range e with an adhesive or a double-sided tape after the racket frame 1 is cured and formed. It is good.

As the main reinforcing fiber constituting the racket frame made of the fiber-reinforced resin of the present embodiment, various fibers such as carbon fiber, glass fiber, boron fiber, and aromatic polyamide fiber can be used. Carbon fibers are also preferable in terms of mass, cost, and the like. As the matrix resin, an epoxy resin, a nylon resin or the like can be used, but an epoxy resin is preferable in view of strength and durability.

The material constituting the mass body 10 may be a resin material having a higher specific gravity than the material constituting the racket frame 1, a metal material, or a material composed of a composite material thereof. .

[0026]

EXAMPLES In order to confirm the effects of the present invention, the following Table 1 was used.
The racket frames of Example 1 and Comparative Examples 1 to 3 shown in FIG.

[0027]

[Table 1]

That is, in the racket frame prepared as the first embodiment, as shown in FIG. 1, the position of the maximum width W of the hitting portion 3 is set at the node 8a of the out-of-plane primary bending vibration M of the racket frame 1.
Is formed so as to be disposed in the vicinity area of.
In order to set the position of the fixed point Q with respect to the hit point P when hitting the ball in the maximum width W position area on the longitudinal axis y of the racket frame 1 within the area that the player grips, A lead weight 1 is placed in a region corresponding to a position 300 mm from the end 6 of the grip portion 4 of the frame 1.
The one provided with 30 g of Oa was prepared.

Further, as Comparative Example 1, a racket frame 1 of Example 1 from which the weight 10a was removed was prepared. Then, in Comparative Example 2, as shown in FIG. 5, one prepared such that the maximum width position of the hitting portion was disposed in the midpoint 34 region of the longitudinal axis of the hitting portion was prepared. Further, in Comparative Example 3, as shown in FIG. 6, the maximum width position of the hitting portion is such that the grip portion 3 is located at a center point 34 of the longitudinal axis of the hitting portion.
The one formed so as to be disposed in the area close to five was prepared. The racket frames of Comparative Example 2 and Comparative Example 3 did not have the weight 10a.

The following tests were performed on the racket frames of Example 1 and Comparative Examples 1 to 3 in order to confirm the rebound characteristics at the time of hitting. That is, as shown in FIG. 8, the racket frame 1 in which
With the grip portion 4 of the hitting portion 3 held and fixed,
The ball 7 collides at a speed (Vo) of 28 m / sec against (the maximum width W position area of the hitting portion 3 on the longitudinal axis y of the racket frame 1), and the speed (Vr) of the rebounded ball
The restitution coefficient was determined from the ratio (Vr / Vo) of the velocity of the incident ball to the index of the repulsion characteristic. The greater the value of the coefficient of restitution, the better the resilience characteristics can be obtained.
The measurement results at this time are shown in Table 2 below.

[0031]

[Table 2]

Further, in addition to the above-mentioned test, an actual hitting test was performed on these racket frames 1. In this actual hit test, the ball 7 was actually hit with a racket frame of Example 1 and Comparative Examples 1 to 3 for a general amateur player, and at that time, the player felt the hit ( Impact and numbness transmitted to the hand) and controllability were evaluated. The test results at this time are shown in Table 3 below.

[0033]

[Table 3]

From the above test results, the racket frame 1 of the first embodiment can obtain a good rebound characteristic at the time of hitting as compared with the racket frames of Comparative Examples 1 to 3, and at the same time have a good feeling at the time of hitting. It was confirmed that an excellent effect was obtained in controllability.

[0035]

As described above, in the present invention, the maximum width position of the hitting portion is set within the range of 0.71L to 0.83L of the total length L of the racket frame from the end of the grip portion, and the ball hits. Since the point is designed to be located near the region corresponding to the node of the out-of-plane primary bending vibration of the racket frame, good resilience characteristics can be obtained at the time of impact.

At the same time, according to the present invention, the fixed point position at the time of hitting the ball at the hit point is 50 mm to 80 m from the end of the grip portion gripped by the player's hand.
m is set to be within the range of
The impact force transmitted to the player's hand at the time of the impact is significantly suppressed, and the hand holding the grip portion does not shake at the time of the impact. As a result, since the energy at the time of hitting is not consumed, it is possible to further improve the resilience characteristics of the racket frame, and at the same time, the player has a good feeling at the time of hitting and a good performance in controllability. It is something that can be done.

Further, in the racket frame of the present invention, by setting the mass before the gut stretching within the range of 200 g to 260 g, good operability can be obtained even for a weak player.

[Brief description of the drawings]

FIG. 1 is an external view illustrating the front and side surfaces of a racket frame according to an embodiment.

FIG. 2 is an explanatory diagram illustrating a linear density distribution of the racket frame according to the embodiment.

FIG. 3 is an explanatory diagram illustrating a linear density distribution before a weight of the racket frame according to the embodiment is provided.

FIG. 4 is an explanatory diagram showing movement of a racket frame when hitting a ball.

FIG. 5 is an external view illustrating the front and side surfaces of a conventional racket frame.

FIG. 6 is an external view illustrating the front and side surfaces of a conventional racket frame.

FIG. 7 is an external view illustrating the front and side surfaces of a conventional racket frame.

FIG. 8 is an explanatory diagram showing a test method.

[Explanation of symbols]

 Reference Signs List 1 racket frame 2 gut 3 hitting part 4 gripping part 5 shaft part 6 terminal part 7 ball 8a section 8b node 9 belly 10 mass body 10a weight 21 racket frame 22 hitting part 23 grip part 24 terminal part 25 ball 31 racket frame 32 face surface 33 Face maximum width position 34 Midpoint 35 Grip part 36 Ball 37 Section

Claims (4)

[Claims] 1. The maximum width position of the hitting portion in a direction perpendicular to the longitudinal axis of the racket frame is 0.71L to 0.8 of the total length L of the racket frame from the end of the grip portion.
The fixed point position of the racket frame when it is within the range of 3L and the maximum width position area on the longitudinal axis of the racket frame as the ball hitting point is 50 mm to 80 mm from the end of the grip portion. A racket frame characterized in that it is set within the range. 2. The racket frame according to claim 1, wherein a maximum width position of the hitting portion is provided near a region corresponding to a node of the out-of-plane primary bending vibration of the racket frame. 3. A total length L of the racket frame from 0.30 L to 0.5 from the end of the grip portion of the racket frame.
The racket frame according to claim 1 or 2, wherein the mass body is disposed within a range of 0L. 4. The racket frame according to claim 1, wherein the weight of the racket frame before the gut is stretched is in a range of 200 g to 260 g.