JP2826954B2 - ball - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball suitable for a ball hitting sport indoors or on a small site.

[0002]

2. Description of the Related Art In recent years, ball games in which a ball is hit by a club, rolled, and cupped in a predetermined hole or passed through a gate in a narrow stadium such as indoors, for persons with disabilities and the elderly. boom. In this type of ball game, since the stadium is small, it is necessary to apply an appropriate braking force to the ball to reduce the distance over which the ball rolls (the reach distance).

Here, in order to apply a braking force to the ball,
If artificial turf or a special sheet is laid in the stadium, the work requires a great deal of labor and a large amount of cost. Therefore, conventionally, various improvements of the ball have been proposed.

[0004] For example, a ball having a large number of cylindrical projections having a height of about 3 mm projecting from its surface is known (Japanese Patent Publication No. 3-1010).
No. 35). This ball gives the ball a braking effect by the projection, but the hardness of the projection is soft,
Further, since the protrusion amount of the protrusion is long, the cushion by the protrusion is large, and the feel of hitting (hitting feeling) and the sound at the time of hitting (hitting sound) are not pleasant.

[0005] Also, there is known a golf practice ball that uses a foamed synthetic resin, has a small surface hardness and weight, and has a short reach (giving a braking force) as a golf practice ball (Japanese Patent Laid-Open No. 34468/1985). Official Gazette, Japanese Utility Model Publication No. 13000). However, since these balls are extremely lightweight and have a low surface hardness, the impact given to the club is very small, so that a shot feeling cannot be obtained and the hitting sound is poor.

There is also known a ball in which a braking force is applied to the ball by making the inside of the ball have an uneven density structure (JP-A-61-369). However, such balls
Since the inside has a rough and dense structure, straightness is extremely poor, and the performance of the game is too much influenced by luck, so it is not suitable for the game.

On the other hand, there is also known a ball which obtains braking performance and straightness by enclosing a fluid and small balls in a hollow spherical shell (Japanese Utility Model Publication No. 56-40454). However, in such a ball, when the impact force due to the impact is large and the ball is broken, the enclosed fluid is scattered.

The present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to provide a ball having excellent braking performance without deteriorating the feel at impact, the hitting sound and the straightness.

[0009]

In order to achieve the above-mentioned object, the present invention provides at least a surface layer comprising a viscoelastic material,
In a spherical solid or hollow ball having a deformation element on the surface that deforms when rolling, as the viscoelastic body,
Loss tangent at a surface hardness of 10 to 40 in the ASTM-D method and an angular frequency ω = 110 Hz
It is characterized in that a viscoelastic body having a maximum value of 0.3 or more at 0 ° C. to 50 ° C. is used.

Here, ASTM stands for American Society.
Abbreviation for Testing and Materials.
This method refers to a method of measuring with a D-type hardness meter having a sharp tip in ASTM-D2240 (ANNUAL BOOK of AST
M STANDARDS VOLUME 08.02 Plastic (11): D1601-D309
9, pp. 309-313 of 1987, and
Overseas Standards Guidebook (Issue: Japanese Standards Association, Publication Date
(August 1977), pp. 99-105). The loss tangent tan δ represents the energy absorptivity due to deformation and is expressed by the following equation (1) (Physics Dictionary, p. 1572-
(See page 1574, Issuer: Baifukan.) tan δ = E ₂ / E ₁ (1) where δ: loss angle E ₁ : storage elastic modulus E ₂ : loss elastic modulus

In the present invention, the reason why the surface hardness in the ASTM-D method is 10 or more is that if the surface hardness is less than 10, the ball is too soft and the hitting sound and hit feeling are impaired. On the other hand, setting the surface hardness to 40 or less means that if the surface hardness is larger than 40, the ball is too hard, and the feel of hitting feels hard, such as damaging the floor or numbing the hand at the time of hitting the ball. Because there is. The surface hardness is generally 2 in relation to the resin to be compounded.
It becomes 0 or more and 40 or less.

Next, a description will be given of the principle of the present invention in which a braking force can be obtained without impairing the feel at impact, hitting sound and straightness. If you dissipate the energy given to the ball at the time of hitting, you can get braking power,
There are two factors in this. One is due to the fact that the ball dissipates energy when the ball is deformed by the impact from the club when hit. Another one
One is that the ball is deformed and dissipates energy due to contact with the floor surface (such as the ground) when the ball rolls.

Here, the present ball is not a perfect spherical shape having a deforming element which is deformed at the time of rolling on its surface, and is made of, for example, a polyhedron as shown in FIG.
As shown in the partial cross-sectional view of FIG.
Roll on L. Therefore, energy is dissipated due to deformation during rolling, and a braking force is obtained. That is, the loss tangent t
By setting an δ larger than a predetermined value and having a deformation element, the ball is deformed while rolling, and the deformation dissipates energy to obtain a sufficient braking force.

In order to increase the energy dissipation at the time of hitting and rolling, it is necessary to provide a large projection on the ball and set the surface hardness to be extremely low, so that the deformation at the time of rolling is set to be large. As in the above-mentioned conventional example (Japanese Patent Publication No. 1035/1991), the cushion caused by the projections becomes too large, which leads to deterioration of shot feeling and shot sound.

Therefore, in order to obtain a braking force using a ball having an appropriate surface hardness without increasing the deformation of the ball when rolling, the energy absorption rate must be increased, that is, the loss tangent tan δ must be increased. It must be set higher than the predetermined value. On the other hand, when the ball is perfectly spherical, even if the loss tangent tan δ is increased, no braking force can be obtained if there is no unevenness on the floor surface. Therefore, in the present invention, the braking performance is obtained by setting the loss tangent tan δ to 0.3 or more and providing the ball with a deformation element.

As described above, the present invention provides the loss tangent tanδ
Is set to be larger than the predetermined value, unlike the conventional long projection, the short projection or the deformation element 10 such as the corner in FIG. A braking force can be applied. That is, even if the deformation amount of the deformation element is small, a sufficient braking force can be obtained. Therefore, the surface hardness of the ball can be made 10 or more, so that the braking force can be applied to the ball without impairing the feel at impact and the impact sound. Since the surface hardness of the ball is moderately hard and the loss tangent tan δ is larger than a predetermined value, the energy is dissipated by the deformation of the ball at the time of hitting the ball. From a viewpoint, it is possible to reduce the reaching distance without impairing the feel at impact and the sound at impact.

Also, as described above, the short protrusions and FIG.
Since the braking force is applied to the ball by the small deformation of the deformation element 10 such as the apex and the ridge line in (a), the ball can be made into a spherical shape close to a sphere. Therefore, the braking force of the ball can be obtained without impairing the straightness of the ball.

In the present invention, the resin constituting the viscoelastic body having the above mechanical properties includes, for example,
A resin containing at least a portion of a copolymer elastomer composed of polystyrene and vinyl isoprene or a copolymer elastomer composed of polyester and polyether can be employed. As the above copolymer elastomer,
"Hybler" (registered trademark (hereinafter the same), manufactured by Kuraray Co., Ltd.), "Hytler" (registered trademark (the same),
(Manufactured by Toray DuPont) or the like can be used.

As the constituent material of the viscoelastic body, styrene elastomers such as "Septon" (registered trademark (hereinafter the same), manufactured by Kuraray Co., Ltd.), "Mirastomer" (registered trademark (hereinafter the same), Mitsui) Other elastomers such as olefin elastomers such as Petrochemical Industries, Ltd. may be included in part.

In the present invention, the preferable shape of the ball having a deformable element on its surface which deforms when rolling is a polyhedron, a sphere having a large number of projections formed on the outer surface of the sphere, or a top of a poly (m) face. A spherical object having m or more projections formed on the surface excluding the surface, or a spherical object having a groove formed on a ridge of a polyhedron, may be used. As the polyhedron, a polyhedron of 60 or more having all vertices on a spherical surface passing through the vertices of the icosahedron is preferable. The deformation element is constituted by the top, ridge and projection of the polyhedron. The ball may be hollow or solid, and may have a double structure having a metal or synthetic resin sphere inside.

The size of the ball is generally 50 mm in maximum diameter.
It is set to about mm to 100 mm. The weight of the ball is generally preferably about 40 g to 200 g, and more preferably about 60 g to 130 g, from the viewpoint of good shot feel and use. The weight per unit volume of the ball is generally set to about 0.7 g / cm ³ or more.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a ball according to an embodiment of the present invention. FIG. 1A shows a first embodiment. In this figure, the ball 1 is composed of a 60-sided body. The shape of the ball 1 composed of the 60-sided body is obtained as follows with reference to the regular icosahedron 2 of FIGS. 2 (a) and 2 (b).

[0023] In FIG. 2 (a), the vertices of the icosahedron 2 and O ₁ ~ O _n, triangle O ₁ O ₂ O ₃ constituting the respective surfaces 21
The geometric center of gravity (face center) of ~ O ₁ O ₆ O ₂ is G ₁ ~
And G _5. The centers of gravity G _{1 of the} surfaces 21 and 21 adjacent to each other,
Conclusion and common vertex O ₁ of G ₂ and the adjacent both sides 21 and 21, which all adjacent surface around the vertex O ₁ 2
When performed for 1 and 21, five new triangles (surface) O ₁ G ₁ to one around the vertex _{O 1 G 2 ~O 1 G 5} G 1 is formed.
Therefore, for the all the 12 vertices O ₁ ~ O _n, if similar, 60 face is formed (fifth surface × 12). Then, the newly formed vertex (center of gravity) G ₁
~G _n projected radially on a spherical surface passing through the vertex O ₁ ~ O _n of the original icosahedron 2 by (movement), FIGS. 1 (a)
Is obtained.

FIG. 3A shows a second embodiment. In this figure, the ball 1A is composed of an 80-face body. The shape of the ball 1A composed of the 80-hedron is obtained as follows with reference to the regular icosahedron 2 in FIG. In FIG. 3B, vertices constituting one triangle of the icosahedron 2 are denoted by O _{1 to} O _3, and each ridge line O ₁ O ₂ , O ₂ O ₃ and O ₃ O ₁
Are A, B, and C, respectively. Now, three midpoints A, B, and C, by projecting (move) in the radial direction on a spherical surface passing through the vertex O ₁ ~ O _n of the original icosahedron 2, the triangle ABC in FIG. 3 (a) It rises outwards like a triangle A ₁ B ₁ C ₁ shown by oblique lines, and four faces A ₁ B ₁ C ₁ , O ₁ C ₁ A ₁ , O with respect to the original one face O ₁ O ₂ O _{3 2} A ₁ B ₁ and O ₃ B ₁ C ₁ are formed. Therefore, if the same is applied to all the surfaces 21 of the regular icosahedron 2 in FIG. 3B, 80 surfaces are formed, and the 80-hedron 1A in FIG. 3A is obtained.

FIG. 4A shows a third embodiment. In this figure, the ball 1B is composed of 240 planes. The shape of the ball 1B composed of the 240-plane is shown in FIG.
(A) 20 points based on the ball 1 composed of 60 faces
It can be obtained by the same method as that for obtaining a regular 80-hedron from a face. In FIG. 4B, vertices forming one triangle of the above-described 60-sided body _{1 are} denoted by O _{1 to} O _3, and each ridge O
The middle points of ₁ O ₂ , O ₂ O _3, and O ₃ O ₁ are A, B, and C, respectively. Now, three midpoints A, B, and C, by projecting (move) in the radial direction on a spherical surface passing through the vertex O ₁ ~ O _n of the original 60 facepiece 1, the triangle ABC in FIG. 4 (a) It rises outward like a triangle A ₁ B ₁ C ₁ shown by oblique lines, and the original one surface
O ₁ O ₂ O ₃ with respect to the four surfaces _{A 1 B 1 C 1, O} 1 C 1 A 1, O 2 A 1 B 1, O 3 B 1
C ₁ is formed. Therefore, the 60-hedron 1 shown in FIG.
By doing the same for all the surfaces 11, the 240 surfaces are formed, and the 240-plane body 1B of FIG. 4A is obtained.

In the present invention, the shape of the polyhedron forming the ball is not limited to the above three types, but various shapes can be adopted. Generally,
As described above, with the regular polyhedron (for example, regular icosahedron) as a reference, the vertices of this regular polyhedron are left as they are, and the newly set vertices are moved in the radial direction to the spherical surface passing through the vertices of the original regular polyhedron, It is preferable to use a polyhedron (m-hedron) having more faces than the original regular polyhedron.

FIG. 5 shows a fourth embodiment. The ball 1C in FIG. 5 has a large number of projections (deformation elements) 12 in FIG. 5 protruding from the surface of the above-mentioned 60-plane (m-plane) 1 in FIG. The position where the projection 12, generally, is preferably a surface excluding the top O ₁ ~ O _n of m tetrahedron vertex O ₁ ~
O _n and a surface 11 excluding the ridge 13 is more preferable.

As shown in FIGS. 6 (a) to 6 (e), the shape of the projection 12 may be various shapes such as a cylinder, a cone, a hemisphere, a truncated cone and a triangular prism. In particular, a conical shape in which the tip of the projection 12 has a sharp point is particularly preferable. This is because the sharpness of the tip increases the amount of deformation of the projection (deformation element) 12 during rolling.

The number and size of the projections 12 are shown in FIG.
As shown in (d) to (g) of FIG. 6, various methods are conceivable. In general, one surface 11 is provided with one or more protrusions 12.
The braking performance and straight running performance are improved.

FIGS. 7A and 7B show a fifth embodiment.
In this figure, a ball 1D is a 60-hedron 1 shown in FIG.
7 is long in the direction along the ridge line 13 in FIG.
This is formed by forming a V-shaped groove 14 in (b). As the cross-sectional shape of the groove 14, various shapes such as a U-shape and a concave shape other than the V-shape can be considered. In addition, instead of the groove 14,
A ridge may be provided along the ridgeline 13 in FIG.

Next, the effects of the present invention will be clarified by showing test examples and comparative examples. First, in order to obtain the peak value of the loss tangent tan δ at 0 ° C. to 50 ° C., test pieces having the following sample dimensions were prepared using the materials shown in Tables 1 to 3. Sample Dimensions Length: 20 to 40 mm Width:. 2 to 4 mm thickness: using a measuring instrument of 0.4 to 0.6 mm angular frequency ω = 110H _Z, 0 ℃ ~50
The storage elastic modulus E ₁ and the loss elastic modulus E ₂ at 0 ° C. were measured at a heating rate of 2 ° C./min. The outline of the measurement conditions is as follows. Vibration displacement: 16 μm (single amplitude) Static tension: 5 g Measurement temperature interval: 2 ° C. Based on the above storage elastic modulus E ₁ and loss elastic modulus E ₂ ,
The loss tangent tan δ at 0 ° C to 50 ° C was determined. The peak value (maximum value) is as shown in Tables 1 to 3.

On the other hand, balls of various shapes were molded with the compositions shown in Tables 1 to 3. The surface hardness was measured by the ASTM-D method and is shown in Tables 1 to 3. Regarding the braking performance, a fixed impact force is applied to a stationary ball using a pendulum-type hitting machine, and the ball is rolled on a flat floor to reach its reach (unit:
m) was measured and indicated. As for the straightness, values obtained by dividing the amount of positional deviation from the original direction in which the ball rolls by the above-mentioned reach distance were obtained, and are shown in Tables 1 to 3. About the shot feeling and the shot sound, five indoor golf instructors
The ball was actually hit with the club, and the feeling is shown in Tables 1 to 3.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

Test Examples 1 to 5 and Comparative Examples 1 to 7: 60
As shown in Tables 1 (a) and 1 (b), a ball 1 composed of a face was molded with a mixture of Hybler and septon or milastomer.

Test Examples 6 and 7: As shown in Table 2 (a), the ball 1 consisting of the above-mentioned 60-hedron was subjected to Hytrel and PV.
C was mixed with the mixture.

Test Examples 8 to 11 and Comparative Examples 9 and 10: The above-mentioned 80-hedron or 240-hedron or sphere ball was formed by blending Hybler with Septon or Mirastomer as shown in Table 2 (b). did.

Test Examples 12 to 18: FIG.
As shown in Table 3, the balls having the protrusions 12 or the grooves 14 shown in FIG. 6 were molded with a mixture of Hybler and Septon or Mylastomer.

The loss tangent tan in Tables 1 (a) and (b)
FIGS. 8A and 8B show the relationship between δ and the reaching distance. As can be seen from these figures, when the loss tangent tanδ is smaller than 0.3, the reach increases sharply. That is,
It can be seen that the braking performance sharply decreases.

As can be seen from Table 1 (b), when the hardness exceeds 40, the shot feeling is hard.

As can be seen from the results shown in Table 2 (a), as the resin constituting the viscoelastic body, in addition to a copolymer elastomer (Hybler) comprising polystyrene and vinyl isoprene, a copolymer comprising polyester and polyether was used. A united elastomer (Hytrel) can be used.

As can be seen from the results of Table 2 (b), in the case of a sphere having no deforming element, even if the loss tangent is large, braking performance cannot be obtained. On the other hand, as the polyhedron constituting the ball, as the number of faces increases, braking performance decreases but straightness improves. It turns out that it is suitable for. Therefore, if the number of polyhedrons is changed according to the size of the stadium, the variety of sports can be enjoyed.

As shown in Table 3, the ball having projections or grooves on the 60-sided body had the same straightness as the 240-sided body of Table 2 (b), and the test of Tables 1 (a) and 1 (b). Compared to the 60-hedrons of Examples 2 and 4, the braking performance was not significantly reduced, indicating that it was the most preferable.

[0045]

As described above, according to the present invention,
Since the surface hardness of the ball is set within a predetermined range, the shot feeling and hitting sound are excellent. In addition, a deformation element that deforms when rolling is provided on the surface, that is, the ball is formed into a sphere having corners and protrusions, and the value of the loss tangent tan δ is set to a predetermined value or more, so that only energy is dissipated at the time of hitting the ball Rather, even if the ball is close to a sphere, the deformation element is deformed when rolling and energy is dissipated, so that the ball has excellent braking performance without impairing straightness.

[Brief description of the drawings]

FIG. 1 (a) is a front view of a ball made of a 60-sided body showing a first embodiment of the present invention, and FIG. 1 (b) is a partially enlarged sectional view of the ball.

FIGS. 2A and 2B are a front view and a plan view of a regular icosahedron, showing a method of forming the above-described 60-sided body based on the regular icosahedron.

FIG. 3 (a) is a front view of an 80-hedron ball showing a second embodiment, and FIG.
It is a front view of a regular icosahedron showing the method of forming a 0-hedron.

FIG. 4A is a front view of a 240-faced ball showing a third embodiment, and FIG.
It is a front view of a 60-sided body which shows the method of forming a 40-sided body.

FIG. 5 is a front view of a ball showing a fourth embodiment.

FIGS. 6A and 6B are a partial perspective view and a partial front view, respectively, showing the shape and arrangement of the projections;

FIG. 7 is a front view and an enlarged partial cross-sectional view showing a grooved ball according to a fifth embodiment.

FIG. 8 is a table showing the relationship between the loss tangent and the reach in Tables 1 (a) and (b).

[Explanation of symbols]

 1, 1A, 1B, 1C, 1D: ball 10, 12: deformation element

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 60-94257 (JP, U) JP-A 63-193059 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) A63B 37/00 A63B 39/00

Claims (1)

(57) [Claims] At least a surface layer is made of a viscoelastic material,
In a spherical solid or hollow ball having on its surface a deforming element which deforms when rolling, the viscoelastic body has a surface hardness of 1 according to the ASTM-D method.
Set to 0 or more and 40 or less, and angular frequency ω = 110 Hz
Loss tangent, tan, obtained by dividing the loss modulus of elasticity by the storage modulus
A ball, wherein δ shows a maximum value of 0.3 or more at 0 ° C to 50 ° C.