JP2563236B2 - Racket frame manufacturing method - Google Patents

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 a racket which can be used for tennis, soft tennis, squash, badminton, racket ball and the like.
Relates to a method of manufacturing a beam, a method of manufacturing a racquet frame for a racket can be adjusted to particular meet requests and strength of the good and strength of the vibration damping.

[0002]

2. Description of the Related Art Conventionally, as a method for manufacturing a racket frame made of this kind of fiber reinforced plastic, a cloth or braid made of glass fiber or carbon fiber is impregnated with a matrix resin such as epoxy resin, and a prepreg is used as a foam core material or a tube. FR which is wound around, inserted into the mold, and cured by heating
A method for manufacturing a P racket frame is known. The addition moth <br/> Las fibers or mixed with carbon fiber chopped fiber-reinforced thermoplastic synthetic resin (FRTP), method for producing FRP racket frame constituted by injection into a mold is known. In addition, the manufacturing method by injection
As a method for manufacturing a racket frame, a core member made of fiber reinforced plastic is used as a strength member, and the outer shell is covered with a fiber reinforced thermoplastic synthetic resin (Japanese Patent Publication No. 59-23224). . In the production method of this La packet frame, a locking pin fitting hole provided on the upper and lower surfaces of the core in the steel fiber reinforced plastic, the locking pin inserted and fixed in the fitting hole, and the insertion fixing By placing the locking pin in the fitting hole provided on the mold surface and arranging it, the core body is held in the mold space and the synthetic resin for forming the outer shell is injected. It was In addition, injectors
As a manufacturing method using a racket frame , a low melting point core is placed in a mold, a thermoplastic material is injected around the core, the molded body is solidified and then heated, and the core is melted and removed to form a racket frame. A method of manufacturing a racket frame configured to be formed is provided (Japanese Examined Patent Publication 5).
9-35632).

[0003]

However, in the conventional racket frame made of fiber reinforced plastic described above,
Those with good vibration damping are weak in strength. Therefore, if the strength is increased, there is a problem that the wall thickness becomes thicker and heavier. On the contrary, if the strength is increased without increasing the weight, there is a problem that the vibration damping is deteriorated. There was no suitable adjustment of strength and vibration damping properties without increasing weight. Further, in the racket frame manufacturing method in which the locking pin fitting holes are provided on the upper and lower surfaces of the conventional core body made of the fiber-reinforced plastic described above, a high injection pressure is applied to the core body, It deforms and collapses. Therefore, there is a problem that the outer shell of the crushed member becomes thick, the weight cannot be reduced, and the vibration damping is not good. In addition, since the core is held in the space inside the mold only by the upper and lower locking pins, the locking pin must be fitted not only in the fitting hole on the mold side but also in the fitting recess of the core. Therefore, it is necessary to form a fitting recess in the core body. However, since the core body is required to be lightweight, it is formed into a hollow tube shape. Forming the fitting recess on the hollow core-like thin core body is advantageous in terms of equipment and working cost even when the fitting recess is formed later in the molded core body. However, there was a problem in actual manufacturing in terms of strength, yield, etc. Further, a low melting point core is placed in a mold, a thermoplastic material is injected around the core, the molded body is heated to melt and remove the core of the racket frame. In the manufacturing method, vibration damping is good, but strength is weak. Therefore, when trying to increase the strength of the racket frame, there is a problem that the wall thickness becomes thick and heavy.

Therefore, the present invention solves the drawbacks of the above-described conventional racket frame manufacturing method, and the racket frame manufacturing method for a racket in which good vibration damping and strength can be adjusted to meet the requirements of the racket. For the purpose of providing.

[0005]

In order to achieve the above object, a method for manufacturing a racket frame according to the present invention comprises a reinforced long fiber.
Mold and cure a prepreg in which fiber is impregnated with thermosetting resin
To form a hollow thin-walled internal structure, and then
The low melting point alloy is injected in the molten state into the hollow of the internal structure.
To cool and solidify, and then fill the inside of the hollow with the low melting point alloy.
The internal structure is placed in the mold space, and then the internal structure is
By injection molding short fiber reinforced resin around the adult
Forming the outer structure, then heating the racket frame,
The low melting point compound filled in the hollow of the internal structure.
The first feature is to melt and remove gold. Book again
The racket frame manufacturing method of the invention has the first feature described above.
In the prepreg, reinforced long fibers are impregnated with thermosetting resin.
Hollow thin-walled internal structure by molding and hardening the leg
Instead of forming the body, yarns and thermoplastics made from reinforced long fibers
Made by braiding a thread made of flexible resin into a tubular shape
To form a hollow thin internal component by
Is the second feature.

[0006]

The operation of the racket frame manufacturing method according to the present invention is as follows.
In the first feature, the reinforced long fibers are impregnated with a thermosetting resin.
External structure that uses injection prepreg and injection molding
Inside the racket frame core for the body
It is formed by winding it into a hollow (cylindrical) shape and then heat-curing it to make it hollow.
Form the internal structure of the meat. The prepreg is heated
Wrap around the burned material that will be
It may be formed thin. In that case, the burned material
Is for the heat curing of the prepreg, or for filling the low melting point alloy
To burn off. Next obtained hollow thin-walled internal structure
It is filled with a low melting point alloy melted against and cooled and solidified.
The internal structure filled with low melting point alloy.
Is made. And this hollow was filled with low melting point alloy
The internal structure is placed in the mold space and the thermoplastic short fiber strength is
The internal structure is made by injection molding the plasticized resin into the mold space.
An outer structure is formed around the. The racket obtained
The frame is heated to melt the low melting point alloy and
The racket frame is completed by removing it from the inside of the adult hollow
It The low melting point alloy is, of course, a thermoplastic short fiber.
Use a resin with a lower melting point than the fiber-reinforced resin. On the other hand, the main
In the second feature of the manufacturing method of Ming racket frame
The internal structure consists of yarns made of reinforced long fibers and thermoplastic resin.
Using a thread made of fat and knitted into a sheet,
Is wound into a hollow shape and then heat-cured to make it hollow.
Form a thin internal structure. Also, the internal structure is reinforced
Hollow combination of long fiber and thermoplastic resin
After being formed into a string, it is cured and used as a hollow thin internal structure.
Good. In addition, in the first and second features, a hollow internal structure
Positioning pins Adult, from those braided consisting of a prepreg impregnated with a thermosetting resin to reinforcing long fibers formed into positioning pins integrally or as reinforcing long fibers and a thermoplastic resin
And down integrally molded, the internal structure which is integrally molded with this positioning pin said fixed with positioning <br/> Me pins integrally molded into the mold space, the short fibers around the inner structure It is also possible to form the outer component by injection molding a reinforced thermoplastic resin and thereby to mold the racket frame. In this case, since the inner structure does not need to be provided with a fitting recess for a positioning pin or the like, the structure or the manufacture of the inner structure becomes very easy. The racket frame according to the first and second features of the present invention described above.
According to the manufacturing method of the
Forming an empty thin internal structure, and the inside of this hollow thin wall
The structure is reinforced with a low melting alloy that can be melted and removed later,
The resin reinforced with short fibers is injected around the inner structure.
By shaping it to form a racket frame
The long fiber reinforced resin strengthens the strength and
High strength with vibration damping improved by fiber reinforced resin
Racket flare that has both high degree and high vibration damping
You can get Also during racket frame formation
In the internal structure, the hollow part is filled with low melting point alloy.
Since the strength is sufficiently improved by
Even if the body is hollow and thin, injection molding of external components
It is not deformed or damaged during shaping,
Therefore, the thickness ratio between the internal and external components can be freely set.
You can change and adjust the characteristics of the racket frame
It Of course, it is the internal structure that is made of prepreg.
This is a drawback when forming with prepreg etc.
Reduce the work time required for the
Limited to the inner structure part. Also, the external component is injection molded.
Because it is a shape, you can finish the surface beautifully and burr
It requires less work after removal. The racket frame
If only injection molding is used to form the meat,
Fiber-reinforced resin cannot be injection molded, resulting in
The strength of the torch frame cannot be enhanced sufficiently. Meanwhile, pre
Using a breg, etc., stack these to make a frame prototype.
Racket by putting this in a mold and heat molding
In the case of forming on the frame, that is, by injection molding
If fleshing is not used at all, stack prepreg, etc.
There are many amounts and processes, and time and labor are required for the stacking work.
It takes a long time, and the heat molding in the mold is a low temperature pressing.
As it takes too long to cure,
There is a problem that it takes a lot of time to manufacture the battery. Also in the mold
In molding, burrs are easily generated and post-processing requires labor.
It In addition, it is easy for bubbles to form after molding, which improves quality and strength.
The problem remains.

[0007]

1 and 2 are obtained by the manufacturing method of the present invention.
FIG. 3 to FIG. 8 are views for explaining an example of the racket frame manufacturing method of the present invention, FIG. 1 is an overall view of the racket frame, and FIG. 1 is a sectional view taken along the line AA of FIG. 1, FIG. 3 is a general view of the internal structure of the racket frame, and FIG. 4 is a state in which a low melting point alloy is injected into the hollow of the internal structure along the line BB of FIG. FIG. 5 is a sectional view, FIG. 5 is a view showing a cavity of one split mold for molding the racket frame, FIG. 6 is a view showing a state in which a positioning member is arranged in the space of one split mold, and FIG. 7 is a space of the mold. FIG. 8 is a sectional view showing a state in which the internal structure is positioned and held, and FIG. 8 is a sectional view showing a state of the racket frame after being taken out from the mold.

With reference to FIGS. 1 and 2, the manufacturing method of the present invention.
An example of the racket frame obtained by the above will be described. The racket frame F includes an internal structure 10 and the internal structure 1.
0 and a resin-made external component 20 formed around 0. The core of the internal structure 10 is hollow 11. The internal structure 10 has a thin wall around the core portion made of a thermosetting resin reinforced with long fibers, and has a thickness of, for example, 0.
It is formed to 5 mm. This internal structure 10 comprises a cloth or braid made of long reinforcing fibers such as glass fibers or carbon fibers, and a prepreg impregnated with a matrix resin (such as epoxy resin) wound around a lightweight member such as a foam core material or a tube. After being inserted into the mold, it is formed by heating and curing. Alternatively, the internal structure 10 is obtained by winding a long reinforced fiber into a sheet-like prepreg by an internal pressure method, and then mounting the prepreg in a mold, introducing a gas into the hollow to apply pressure, and heating while applying internal pressure to cure. You may form by making it. Examples of the thermosetting resin that molds the internal structure 10 include epoxy resin and unsaturated polyester resin.

In the above description of the racket frame,
Although the thermosetting resin reinforced with long fibers is used as the internal structure 10, a thermoplastic resin reinforced with long fibers may be used instead. In this case, the internal structural body 10 is formed by knitting a yarn made of reinforcing fibers such as glass fibers and carbon fibers and a yarn made of a thermoplastic resin into filaments into a sheet shape, which is a lightweight member such as a foam core material or a tube. Wrapped around,
It can be formed by inserting it into a mold and then heating and cooling to cure it. Also, knitted into the above-mentioned sheet,
After formation into a tubular shape, fitted in a mold, pressed by introducing gas into the hollow, it can be formed by heating and curing while applying pressure. Furthermore, the internal structure 1
0 is a hollow braid composed of a yarn made of reinforced long fibers and a yarn made of a thermoplastic resin, which is mounted in a mold,
It can be formed by introducing a gas into the hollow, pressurizing it, and heating it while applying an internal pressure to cure it. Examples of the thermoplastic resin that molds the internal structure 10 include nylon resin, polycarbonate resin, polyphenylene oxide resin, and the like.

The outer structure 20 is formed around the inner structure 10 from a thermoplastic resin reinforced with short fibers. The external structure 20 is formed into a thin layer by injection molding a thermoplastic resin reinforced with short fibers such as glass fibers and carbon fibers or chopped fibers. The thickness of the external component 20 is, for example, about 2 mm. Examples of the thermoplastic resin forming the outer structure 20 include nylon resin, polycarbonate resin, polyphenylene oxide resin, and the like, as described above.

Next, an embodiment of the racket frame manufacturing method of the present invention will be described with reference to FIGS. First,
The internal structure 10 shown in FIG. 3 uses a sheet-like prepreg obtained by arranging long reinforcing fibers in a thermosetting resin that is a matrix, and after winding the prepreg into a hollow or winding it on a heat-burnt material. After that, it is mounted in a mold, a gas is introduced into the hollow by an internal pressure method to pressurize, and it is heated and cured while applying an internal pressure to form it.

The inner structure 10 is made by knitting a yarn made of reinforced long fibers and a yarn made of a thermoplastic resin into a sheet as its material, and a racket for an outer structure to be injection molded. To be the core of the frame
It may be formed by winding it into a hollow shape, mounting it in a mold, heating and cooling it while introducing gas into the hollow and applying internal pressure, and hardening it to form a hollow thin wall, or strengthening. After forming a long braided yarn and a thermoplastic resin yarn into a hollow braid, this is attached to a mold and heated and cooled while applying internal pressure in the hollow to harden it to form a hollow thin wall. Good. ,

Next, the internal structure 1 formed as described above.
As shown in FIG. 4, the low-melting-point alloy 12 is injected into the core of the hollow 11 of No. 0 from the opening of the grip end 14 to fill the inside of the hollow 11. As the low melting point alloy 12, lead,
Examples of the alloy include tin, bismuth, cadmium and the like. The melting point of the low melting point alloy 12 needs to be lower than the melting temperature of the thermoplastic resin described later. As the low melting point alloy 12, an alloy having a melting point of about 110 to 180 ° C. is usually used.

Further, the inner structure 10 filled with the low melting point alloy 12 is mounted on the mold 30 to form a racket frame. The mold 30 is, for example, as shown in FIGS. 5 to 7, a split mold 31, which can be divided into two parts by a plane perpendicular to the thickness direction of the racket frame (a plane parallel to the face surface of the racket).
32 (see FIG. 7), each split mold 31, 32 is provided with grooves 33, 34 for forming a mold space 40. By combining the two grooves 33 and 34, a mold space 40 is completed in the mold 30, and the space 40 is formed in the mold space 40.
The entire internal structure 10 shown in FIG. The inner structure 10 is a core of the racket frame, and the resin 40 is injection-molded into the space 40 around the inner structure 10, so that the resin outer structure 20 is formed around the inner structure 10 to form a racket frame. It is formed. Therefore, the internal structure 10 needs to be held and positioned without contacting the inner surface of the mold 30 around the internal structure 10.

In this embodiment, the internal structure 10 is attached to the mold 30.
As a positioning member for positioning in the space 40, resin-made positioning pins 50 are arranged so as to project into the mold space 40 from above and below and from the left and right of the inner surface of the mold.
Therefore, in this embodiment, as shown in FIG. 7, insertion holes 35a and 35b are provided at appropriate intervals on the bottom surface 33a and the side surface 33b of the groove 33 of one split die 31, and the split die 32 on the other side. Insertion hole 36a in the bottom surface 34a of the groove 34
Is provided. Each of the insertion holes 35a, 35b, 36a
By inserting the resin-made positioning pin 50 into the, the positioning pin 50 comes into contact with the internal component 10 from above and below and from the left and right, and the internal component 10 can be positioned and arranged at a predetermined position in the mold space 40. .

The groove 33 of the one split mold 31 is shown in FIG.
As shown in, two fixing protrusions 37 are provided from the bottom surface 33a at a position corresponding to the grip position of the racket frame. A mounting hole 13 is provided at a position corresponding to the grip of the internal structure 10 with respect to the fixing projection 37. In FIG. 5, reference numeral 38 is a molten resin injection passage.

In the manufacture of the racket frame of this embodiment, first, the hollow internal structure 10 is formed as described above. A low melting point alloy (mp 140 ° C.) is melted and injected into the hollow of the internal structure 10, and the inside of the hollow 11 is filled and solidified. Next, the positioning pin 50 made of resin is inserted into the insertion holes 35a, 35b, 36a of the split dies 31, 32 of the die 30. Next, the inner structure 10 is fitted into the fixing projection 37 in one split mold 31, and the entire inner structure 10 is mounted in the groove 33 of the split mold 31. Then, the other split mold 32 is fitted to the split mold 31.
As a result, the upper and lower surfaces and the left and right surfaces of the internal structure 10 are positioned and arranged in the mold space 40 while being in contact with the resin positioning pins 50 of the split molds 31 and 32. After that, a thermoplastic resin reinforced with short fibers, such as nylon, is injected from the injection passage 38 into the mold space 40, so that the resin outer structure 20 is formed around the inner structure 10. . After injection molding, split molds 31, 32
Open and take out the molded racket frame. At this time, the resin positioning pin 50 is also taken out of the mold 30 together with the racket frame as a part of the meat of the outer structure 20 of the racket frame (FIG. 8).

Then, the racket frame is heated to 150 ° C. in an oven (not shown) to remove the low melting point alloy 12 from the grip end portion 14. This heating temperature is equal to or higher than the melting point of the alloy and equal to or lower than the melting temperature of the thermoplastic resin of the external component 20. That is, of course, the manufacturing method of the present invention
The thermoplastic resin used in
It must have a melting point above the point. For example, the low melting point
As the alloy, a known alloy having a temperature of 110 to 180 ° C., for example,
Composed of lead, tin, bismuth, cadmium, etc.
Use known alloys and change these compounding ratios appropriately.
For example, it has melting points at various temperatures such as the above 110 to 180.
You can get the alloy freely, but if you do
The low melting point alloy 12 is
Nylon resin, polycarbonate resin, polyfe mentioned above
The melting point of the nylene oxide resin is the low melting point alloy 1
It must have a melting point higher than 2. Nylon resin mentioned above
When used with low melting point alloy 12 with a melting point of 140 ° C
Nylon resin generally has a melting point of about 250 degrees.
However, in the case of fiber-reinforced nylon resin, the melting point is
Since it becomes higher, the low melting point alloy of 140 ° C.
There is no problem in melting and removing at temperature. On the other hand, already
Polycarbonate resin and polyphenylene oxai described above
In the case of resin, its melting point is generally around 150 ° C.
It is fiber reinforced and its melting point is slightly higher.
With polycarbonate resin and polyphenylene oxide
When the resin is used as a thermoplastic resin,
The point alloy 12 has a melting point lower than 150 ° C.
Need to be used. Then, the low melting point alloy 12 is melted and removed.
The heating temperature for the melting is set to a low melting point with the thermoplastic resin used.
To adopt a temperature between the melting points of gold 12
Become. For the racket frame taken out of the mold
Is the portion of the positioning pin 50 protruding from the outer surface of the racket frame (the insertion holes 35a, 3a of the die 30).
5b and 36a) are removed. After that, drill a gut hole and attach a grip, end cap, gut, etc. to make a racket. The order of removing the low melting point alloy 12 and scraping off the positioning pin 50 is not limited to the above embodiment.

In the above embodiment, the resin-made positioning pin 50 is used as the positioning member for positioning the internal structure 10 in the mold space 40, and this is inserted into the insertion holes 35a, 35b, 36a of the mold 30. As explained in the example,
The present invention is not limited to the above embodiment. First, when a resin positioning member is used, the positioning pin 50 does not have to be the positioning pin 50, and the positioning pin 50 contacts the surface of the internal structure 10 so as to project from the inner surface of the mold 30 toward the space 40. I wish I had. Secondly, the resin positioning member is the mold 3
Without being inserted into the insertion holes 35a, 35b, 36a of 0, or attached to the inner surface of the mold 30 or the mold 30
It is also possible to just abut and interpose both between the inner surface and the internal structure 10. By configuring the resin positioning member in this way, it is not necessary to form the insertion holes 35a, 35b, 36a on the inner surface of the mold 30, and after injection molding the outer structure 20, In the above, since the positioning member does not project from the outer structural body 20 of the racket frame, a post process of scraping off the projecting portion is not necessary. The present invention also includes in its technical scope a manufacturing method having such a resin positioning member and a mold.

In the above-mentioned embodiment, the resin positioning member including the resin positioning pin 50 is made of resin in order to make it easy to fit in with the external structural body 20 formed by injection molding. , External component 2
In addition to the same resin as 0, various thermosetting resins and thermoplastic resins can be selected, except for a resin whose softening temperature is extremely lower than the melting temperature of the resin of the external component 20.
Of course, if the resin positioning member can play a role of positioning, it does not re-melt when the external component 20 is injection-molded to form an interface with the tissue of the external component 20. Is preferred.

As in the above embodiment, since the inner structural body 10 is made of long fiber reinforced (thermosetting, thermoplastic) resin and the outer structural body 20 is made of short fiber reinforced resin, the strength of the racket frame is improved. This can be achieved by the internal structure 10, and the damping characteristics can be adjusted by the material and thickness of the external structure 20. When injection molding the outer component 20, the inner component 10
Since the inside of the hollow 11 is filled with the low melting point alloy 12, it is possible to prevent the internal structure 10 from being crushed even when molding with a high injection pressure. Therefore, the injection amount of the thermoplastic resin for forming the external structure 20 can be controlled accurately. Therefore, the ratio of the thickness of the inner structure 10 to the thickness of the outer structure 20 and the weight of the racket can be arbitrarily changed. as a result,
Appropriate strength and vibration damping property can be obtained, and one of the features can be emphasized by changing the thickness ratio. Further, since the low melting point alloy 12 filling the hollow 11 is heated and melted and injected, the casting step of forming a specific shape as in the prior art can be omitted and most of it can be recovered. As a result, the cost can be reduced.

FIG. 9 is a drawing obtained by the manufacturing method of the present invention.
FIG. 10 is a partial cross-sectional view of the frame for explaining another example of the ket frame, and FIG. 10 is a partial cross-sectional view of the frame for explaining the manufacturing method thereof. In this example,
The racket frame is composed of an internal structure 10 and an external structure 20. In the internal structure 10 of this embodiment, a positioning projection 15 in the vertical direction (thickness direction of the racket frame) and a positioning projection 16 in the horizontal direction (width direction of the racket frame) are integrated on the surface thereof. ing.
Others are the same as the racket frame of the first embodiment described above.

[0023] The FIG. 10, a manufacturing method of another embodiment in of these present invention. In this alternative embodiment, the grooves 31 and 32 of the mold 30 are not provided with positioning pin insertion holes in the bottom and side surfaces thereof. Also, the internal structure 10 is formed as described in the above-mentioned embodiments. The internal structure 10 and the positioning protrusions 15 and 16 of this embodiment may be integrally molded, or may be integrally fixed to the internal structure 10 at the same time when the internal structure 10 is molded. May be. Since the external component 20 is formed of a plastic different from that of the internal component 10, the external component 20
It is preferably formed of the same plastic as.

Next, the low melting point alloy 12 is injected into the inner structure 10 to fill the inside of the hollow 11. The positioning protrusion 1
The internal structural body 10 integrated with 5, 16 and filled with the low melting point alloy 12 is fitted into one split mold 31 of the mold 30, and then the other split mold 32 is fitted to the split mold 31.
As a result, the upper and lower surfaces of the inner structure 10 and the left and right resin-made positioning protrusions 15 and 16 are positioned and arranged in the mold space 40 in a state of being in contact with the inner surface of the mold 30. Then, the short fiber reinforced thermoplastic resin is injected into the mold space 40 from the injection passage, so that the resin-made external component 20 is formed around the internal component 10. After injection molding,
Open the split mold and take out the molded racket frame. At this time, the positioning projections 15 and 16 made of resin are also taken out from the mold together with the racket frame as a part of the meat of the outer structural body 20 of the racket frame. Since the positioning protrusions 15 and 16 made of resin are integrated with each other in contact with the inner surface of the mold 30, they do not protrude from the outer surface of the racket frame, so that no work for scraping is required. .

FIG. 11 shows a racket obtained by the manufacturing method of the present invention.
FIG. 14 is a partial cross-sectional view of an internal structure for explaining still another example of the frame . As shown in FIG. 11, the racket frame of this embodiment includes an internal structural body 60 and a resin external structural body 70 formed around the internal structural body 60, and a core portion of the internal structural body 60. Has a hollow 61. The cross-sectional shape of the racket frame of this embodiment is formed into a substantially elliptical shape, and has a step portion 62 on the center plane side.

The internal structure 60 of the racket frame of this embodiment is formed by the method described above. Then, the low melting point alloy 12 is injected into the inner structural body 60 to fill the inside of the hollow 61, then the outer structural body 70 is formed, and the low melting point alloy 12 is melted and removed to manufacture a racket frame. According to the racket frame of this embodiment, the low melting point alloy 12 is injected into the hollow 61 of the inner structure 60 even when the inner structure 60 having a modified cross section and the outer structure 70 are formed by injection molding. The inside of the hollow 61 is filled. Therefore, even if the injection molding pressure is applied, the deformation of the internal structural body 60 can be prevented,
It is possible to prevent the wall thickness of the outer structure 70 from locally increasing and changing the ratio of the wall thicknesses of the inner structure 60 and the outer structure 70. As a result, it is possible to easily adjust the strength and the vibration damping property.

[0027]

According to the method of manufacturing the racket frame of the present invention, the present invention has the above-described structure and operation .
Molded prepreg in which reinforced long fibers are impregnated with thermosetting resin
And then cured to form a hollow thin internal structure
Then, melt the low melting point alloy into the hollow of the internal structure.
In the solid state, cooled and solidified, and then hollowed with the low melting point alloy
Place the filled internal components in the mold space, then
Injection molding a short fiber reinforced resin around the inner structure
To form the outer structure, and then the racket frame
Before heating and filling the hollow inside of the internal structure
Serial Since followed by removal a low melting alloy, long fiber
Strengthened by fiber reinforced resin and short fiber reinforced resin
Therefore, high strength and high vibration damping with improved vibration damping
A hollow racket frame that combines both characteristics of sex
Obtainable. Also during the racket frame formation
The inner structure is filled with a low melting point alloy in the hollow part.
By doing so, the strength can be sufficiently improved so that the internal structure is
Even if it is empty and thin, it can be used for injection molding of external components.
It will not be deformed or damaged when
Freely change the thickness ratio of internal and external components
Then, the characteristics of the racket frame can be adjusted.
Of course, only the internal structure is formed by prepreg.
Therefore, there is a problem that is a drawback when forming with prepreg etc.
The labor can be reduced and it can be formed with prepreg.
If there is a limited part of the frame
It can be limited to the internal structure part that is
It is possible to reduce the adverse effect on it. Also, the external structure
Since the adult is injection molded, the surface should be finished beautifully.
Can be, it requires less work after the deburring and the like. Claim 2
According to the method for manufacturing a racket frame described in
The same effect as that described in 1 can be obtained.
In addition, both internal and external components are made of thermoplastic resin.
Both components are formed using the same resin by using fat.
Adhesiveness at the interface of both components
Can also be improved sufficiently.

[Brief description of drawings]

FIG. 1 is a racket frame obtained by the manufacturing method of the present invention.
It is a general view for explaining an example of a program .

2 is an A-A sectional view of FIG.

FIG. 3 is an overall view of an internal structure for explaining one embodiment of the racket frame manufacturing method of the present invention.

4 is a cross-sectional view showing a state in which a low melting point alloy is injected into the hollow of the internal component taken along the line BB in FIG.

FIG. 5 is a view showing one split mold cavity portion for explaining the embodiment.

FIG. 6 is a view showing a state in which a positioning member is arranged in one split mold space for explaining the above-mentioned embodiment.

FIG. 7 is a cross-sectional view showing a state in which an internal structural body is positioned and held in a space of a mold for explaining the above embodiment.

FIG. 8 is a cross-sectional view showing a state of the racket frame after being taken out from the mold for explaining the embodiment.

FIG. 9 is a racket frame obtained by the manufacturing method of the present invention.
It is a sectional view of a part of frame for explaining another example of the dome .

FIG. 10 is a partial sectional view of a frame for explaining another embodiment of the racket frame manufacturing method of the present invention.

FIG. 11 shows still another layer obtained by the production method of the present invention.
It is a sectional view of a part of internal structure for explaining an example of a ket frame .

[Explanation of symbols]

 10 Internal Configuration 20 External Configuration 30 Mold 40 Space 50 Resin Positioning Pin 60 Internal Configuration 70 External Configuration

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-1-121074 (JP, A) JP-A-58-61765 (JP, A) JP-A-3-247362 (JP, A) JP-A-3- 159665 (JP, A) JP 61-45782 (JP, A) JP 58-212464 (JP, A)

Claims (2)

(57) [Claims] 1. A reinforced filament is impregnated with a thermosetting resin.
Hollow thin-walled interior by molding and curing the prepreg
Forming a structure, and then having a low melting point in the hollow of the internal structure.
The alloy is poured in the molten state, cooled and solidified, then the low melting
Inside the mold space, fill the hollow interior with a point alloy.
And then place a short fiber reinforced resin around the internal structure.
The outer component is formed by injection molding and then the
Heat the heating frame and fill the hollow inside of the internal structure.
Characterized by melting and removing the low melting point alloy
Racket frame manufacturing method. 2. A reinforced continuous fiber impregnated with a thermosetting resin.
Hollow thin-walled interior by molding and curing the prepreg
Instead of forming a construct, a thread made of reinforced filaments and heat
A braid with a thread made of a plastic resin is formed into a tubular shape.
And cure to form a hollow, thin-walled internal structure
The method for manufacturing a racket frame according to claim 1.