JPH03211042A - Manufacture and manufacturing device for round belt - Google Patents

Abstract

PURPOSE:To improve freedom in selection of a material and manufacturing condition and manufacture an annular round belt whose strength is improved, by a method wherein after a belt material is filled into a cavity with centrifugal force by a die, the belt material is cured under a state where a rotation of a die is kept on and the belt material is molded swiftly into a fixed form. CONSTITUTION:Dies 5, 6, 7 each are turned unitarily following to a rotation of a shaft 3a. Then a die 4 is heated, for example, at 100 deg.C under this turned state and liquid rubber is loaded within the die 4. For example, liquid polyether polyurethane is adopted as the liquid rubber. Since the cast liquid rubber receives centrifugal rubber with turning, the same is filled sway swiftly into cavities S1-S8 and flash grooves F1-F8. After the cavities S1-S8 are filled with the liquid rubber after the lapse of a fixed time after loading of the liquid rubber, the liquid rubber is deaerated under a state where this turning is kept on and cured in a fixed time in succession. With this curing, the liquid rubber is formed into a fixed form corresponding to the cavities S1-S8 and flash grooves F1-F8.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method and apparatus for manufacturing round belts, etc.
In particular, it relates to measures for improving workability and belt strength.

(Prior Art) Ring-shaped round belts for transmitting light loads, which are often used in household electric appliances, have been generally known. This ring-shaped round belt is made of polyether urethane rubber or the like and has a circular cross section and an annular shape.

Conventionally, this ring-shaped round belt has been manufactured by injection molding, in which heated thermoplastic urethane rubber is forced into a mold and molded into a predetermined shape. Other manufacturing methods include a cast press method in which liquid thermosetting urethane rubber is filled into a mold and heated, and a material processing method in which a rubber material is processed to form a predetermined shape.

(Problems to be Solved by the Invention) However, the conventional manufacturing methods as described above have the following problems. In other words, the injection molding method and the cast press method are subject to restrictions on the selection of materials. In other words, when a round belt as a product is required to have low hardness, low permanent elongation, wear resistance, and heat resistance, applicable materials are restricted. Additionally, there were restrictions on the pot life, which is the time it takes for a fluid rubber material to harden, and the viscosity of the rubber material in its fluid state, making it complicated to set processing conditions for the rubber material and other components. . Further, during operation of the belt manufactured by such a manufacturing method, there is a risk that the belt may be cut at a weld line portion where the belt material is insufficiently fused or at a gate portion where the belt surface is subjected to post-processing. Furthermore, the processability of the liquid thermosetting urethane rubber is poor in the casting press method and the material processing method.

The present invention has been made in view of these problems, and aims to provide a manufacturing method for manufacturing a ring-shaped round belt with improved flexibility in material selection and processing conditions, and improved strength. .

(Means for Solving the Problems) In order to achieve the above object, in the present invention, liquid rubber is used as a belt material, and this liquid rubber is press-fitted into a mold cavity by centrifugal force and molded. Specifically, the invention of claim (1) is a method for manufacturing a rubber round belt, etc., which has a cavity with a circular cross section extending in the circumferential direction, and in which the cavity is formed in a divided portion of the inner circumferential surface. A ring-shaped mold having a continuous opening for injecting the belt material is prepared around the entire circumference. Then, a fluid curable belt material is poured into the cavity through the opening by centrifugal force generated by the rotation of the mold around the center of the ring, and is then cured while the mold continues to rotate. I made it.

Further, the invention of claim (2) provides a manufacturing apparatus for carrying out the method according to the invention of claim (1), which is a mold member that is formed by overlapping a plurality of ring-shaped mold members and is polymerized. A mold having a circular cross-sectional cavity extending in the circumferential direction is formed in between, and an opening for injecting the belt material that communicates with the cavity is formed around the entire circumference at the overlapping part of the inner peripheral surface of the mold member. and a driving means for driving the mold to rotate around the center of the ring so that a fluid curable belt material flows into the cavity from the opening by centrifugal force.

(Function) According to the manufacturing method according to the invention of claim (1), after the belt material is poured into the cavity by the centrifugal force caused by the rotation of the mold, the belt material is cured while the rotation of the mold is maintained. Therefore, by quickly forming the belt material into a predetermined shape, it is possible to uniformly form the entire circumference of the belt, but there are no weld lines or gate areas.
This improves belt strength. Furthermore, since a belt material with good fluidity is used, flexibility in viscosity and pot life can be improved.

According to the manufacturing apparatus according to the invention of claim (2), the cavity and the belt injection opening are formed simply by overlapping the mold members, so that the manufacturing operation of the round belt is simplified.

(Example) Next, one embodiment of the present invention will be described with reference to the drawings.

First, the belt manufacturing apparatus will be explained.

As shown in FIG. 3, the belt manufacturing apparatus 1 has a base 2. As shown in FIG. This base 2 is a frame having a substantially pentagonal shape when viewed from the front,
Its upper surface forms a mold support surface 2a inclined at approximately 45 degrees. A shaft 3a inclined along the support surface 2a is rotatably attached to the mold support surface 2a via shaft support members 2b and 2c. This shaft 3a is slightly above the lower shaft support member 2C,
A pulley 3b is fixed to rotate integrally. On the other hand, a motor 3d having a drive shaft 3C whose axis is parallel to the shaft 3a is disposed below the mold support surface 2a of the base 2,
A pulley 3e is attached to the drive shaft 3C of the motor 3d, and a V-belt 3f is passed between the pulley 3e and the pulley 3b of the shaft 3a, and the driving force of the motor 3d is applied to the V-belt 3f. It is configured to be transmitted to the shaft 3a via.

Furthermore, as shown in FIG. 1, this shaft 3a has a tapered upper end portion, and a screw hole 3h is formed in the center of the tip end surface 3g.

A mold 4 is rotatably attached to the tip of the shaft 3a. As shown in FIGS. 1 and 2, this mold 4 includes a lower mold 5, a plurality (seven in this example) of middle molds 6, 6.・
..., an upper die 7 and a plurality of fastening members 8.

The lower die 5 is a disk-shaped member, and a boss portion 5b having a tapered mounting hole 5a into which the tapered end portion of the shaft 3a is inserted is formed in the center thereof. Also,
A circumferential groove 5C is formed in the upper surface of the lower mold 5 near the outer peripheral edge thereof. The circumferential groove 5C has a substantially semicircular vertical cross section with a predetermined radius r (2.5 mm in this example), and the circumferential length at the center of the semicircular cross section is set to, for example, 980 mm. . Further, the outer surface 5d located on the outside of the circumferential groove 5C is located above the inner surface 5e located on the inner side of the circumferential groove 5C by a predetermined dimension S (approximately 0.1 mm in this example), and this outer surface 5d A step portion 5f having the same height as the inner surface 5e is recessed in the ridgeline portion of the circumferential groove 5C. Further, the outer edge of the outer surface 5d has a step portion 5 facing downward.
A plurality of screw holes 5i, 5i, . . . are formed through the outer peripheral edge 5h of the stepped portion 5g at equal intervals in the circumferential direction.

Each of the middle molds 6 is a ring-shaped member having the same configuration, and its outer diameter is set to be larger than the diameter of the stepped portion 5g of the lower mold 5 and smaller than the diameter of the position where the screw hole 51 is formed. has been done. Then, on the upper and lower surfaces of each medium mold 6, the lower mold 5
Similar circumferential grooves 6a, 6 are provided at positions corresponding to circumferential grooves 5C.
b is recessed. Similarly to the lower mold 5, the outer surface 6C located on the outside of the circumferential groove 6a formed on the upper surface side of the middle mold 6 is located above the inner surface 6d located on the inner side of the circumferential groove 6a by the predetermined dimension S. A step portion 6e having the same height as the inner surface 6d is recessed in the ridgeline between the outer surface 6C and the circumferential groove 6a. On the other hand, the outer surface 6f located on the outside of the circumferential groove 6b formed on the lower surface side is located below the inner surface 6g located on the inner side of the circumferential groove 6b by a predetermined dimension S, and the outer surface 6f and the circumferential surface Groove 6b
A stepped portion 6h having the same height as the inner surface 6g is recessed in the ridgeline portion. Further, the outside of the upper outer surface 6C corresponds to the shape of the step 5g of the lower mold 5 and extends downward to a step 61, while the further outside of the lower outer surface 6f corresponds to the shape of the step 5g of the lower mold 5. A step portion 6 that goes downward in accordance with the shape of the step portion 5g.
Each is consecutive to j. It should be noted that a plurality of these medium molds 6 are prepared depending on the number of round belts to be manufactured in one process.

The upper mold 7 is basically a ring-shaped member similar to the middle mold 6, and its outer diameter is set to be approximately the same size as the lower mold 5. A circumferential groove 7a similar to that of the lower mold 5 and the middle mold 6 is formed in the lower surface of the upper mold 7 near its outer periphery. Also, the outer surface 7 located outside this circumferential groove 7a
b is located below the lower surface 7C located inside the circumferential groove 7a by the predetermined dimension S, and a step portion 7d having the same height as the inner surface 7C is provided on the ridgeline between the outer surface 7b and the circumferential groove 7a.
is recessed. Furthermore, a step portion 7e extending downward matching the shape of the step portion 61 of the medium mold 6 is formed further outside the outer surface 7b, and an outer peripheral edge portion 7f on the outside of the step portion 7e.
, a plurality of through holes 7g are formed corresponding to the screw holes 51 of the lower mold 5.

The fastening member 8 is for integrally assembling the molds 5, 6.7, and includes an insertion portion 8a having a diameter that allows insertion through the through hole 7g of the upper mold 7, and a tip of the insertion portion 8a. , lower mold 5
a threaded portion 8b that is screwed into the screw hole 51 of the
It consists of a grip part 8C formed at the upper end of the.

With this configuration, when each mold 5, 6.7 is assembled, a cavity with a circular cross section is formed by each peripheral groove 5c, 6a, 6b, 7a, and each step 5
f, 6e, 6h, and 7e form openings for injecting belt material.

Next, a belt manufacturing method using the belt manufacturing apparatus 1 described above will be explained. First, the molds 5, 6.7 of the molds described above are assembled onto the shaft 3a. In this case, the shaft 3 is inserted into the upper end of the shaft 3a with the boss portion 5b of the lower mold 5
A bolt 9 with a seat is screwed into a screw hole 3h formed in the tip end surface 3g of the shaft 3a, and by tightening the bolt 9, the lower die 5 is attached to the shaft 3a so as to rotate integrally. Thereafter, the middle mold 6 is placed on the lower mold 5 with the step 5g of the lower mold 5 and the lower step 6j of the first middle mold 6 aligned. As a result, a cavity S1 having a circular cross section is formed by the circumferential groove 50 on the upper surface of the lower mold 5 and the circumferential groove 6b on the lower surface of the middle mold 6.

After that, the second and subsequent sheets (6 sheets in this example)
Medium size 6,6. ... are overlapped with each step portion 6i, 6j aligned. As a result, each of the medium molds 6, 6. Cavities S2 to S7 similar to the cavity S1 are also formed between the upper circumferential groove 6a and the lower circumferential groove 6b of the middle mold 6 placed above it.

Furthermore, with the upper mold 7 in a state where the position of the through hole 7g corresponds to the position of the screw hole 51 of the lower mold 5, the uppermost middle mold 6 is
Place it on. As a result, a cavity S8 is formed by the upper circumferential groove 6a of the uppermost middle mold 6 and the circumferential groove 7a formed in the upper mold 7. Then, as described above, each mold 5. 6. The heights of the upper and lower surfaces of the circumferential grooves 5c, 6a, 6b, and 7a are different on the inside and outside of each circumferential groove 5c, 6a, 6b, and 7a. ．． 2mm annular opening 1
0 is formed. Furthermore, the above-mentioned stepped portions 5f and 6e are provided on the outer peripheral side of each of the cavities 81 to S8.

Paris grooves F1 to F8 are formed by 6h and 7e.

In this way, each type 5. 6. 7 are stacked on top of each other, each of the molds 5, 6. Assemble 7 in one piece.

After that, when the motor 3d is driven, its rotation is transmitted to the shaft 3a via the V-belt 3f.
With the rotation of a, each mold 5, 6° 7 rotates integrally. The rotation speed of the mold 4 at this time is set to 700 r, p, m, etc. Then, in this rotated state, the mold 4
is heated to, for example, 100° C., and liquid rubber is poured into the mold 4. This liquid rubber is made of, for example, liquid polyether polyurethane, mixed with a compounding agent such as adipic acid, and heated to approximately the same temperature as the mold temperature.

Then, the injected liquid rubber is quickly transferred from the opening 10 to the cavity 8 in order to receive the centrifugal force caused by the rotation.
1 to S8 and paris grooves F1 to F8. After a predetermined period of time has elapsed since the injection of the liquid rubber, and the cavities 81 to S8 are filled with the liquid rubber, the liquid rubber is degassed and heated for a predetermined period of time (for example, 5 minutes) while maintaining this rotation. Let it harden. By this curing, the liquid rubber is formed into a predetermined shape corresponding to the cavities 81 to S8 and the paris grooves F1 to F8. After that, the rotation of the motor 3d is stopped,
Place mold 4 in the reverse order to each mold 5. 6. 7 is divided to obtain a belt body 11 as shown in FIG. Thereafter, the burrs protruding from the inner and outer circumferential sides of the belt body 11 are cut to obtain a ring-shaped round belt as a product.

As described above, in the method according to this embodiment, since liquid rubber is used, the viscosity and pot life can be improved. Moreover, since the cavities S1 to S8 can be quickly filled with liquid rubber by centrifugal force, the entire circumference of the belt can be uniformly formed, and the strength of the belt is improved. Furthermore, by a simple operation such as changing the rotation speed of the mold 4, centrifugal force, that is, liquid rubber can be transferred to the cavities 81~
The pressure at which S8 is filled can be changed. Furthermore, paris grooves F1 to F8 are provided on the outer circumferential side of the cavities 81 to S8.
Therefore, even if air 4 remains in the cavities 81 to S8 when filling the liquid rubber, this air will be forced into the paring grooves F1 to F8, and the liquid rubber will not be in the cavities 81 to S8. It is possible to prevent unfilled portions from occurring.

In addition, in this embodiment, a case has been described in which seven medium-sized molds 6 are used and eight belts are taken in the - process, but if the number of medium-sized molds 6 is increased, a larger number of belts can be obtained in the - process. You can also.

(Effects of the Invention) As described above, according to the manufacturing method according to the invention of claim (1), after the belt material is filled into the cavity by the centrifugal force caused by the rotation of the mold, the rotation of the mold is maintained. By quickly forming the belt material into a predetermined shape in order to harden the belt material in a state where the belt material is Due to its absence, there is no part that causes breakage during operation, and belt strength is improved. Also,
Since a fluid belt material is used, the viscosity of the belt material during molding and the flexibility of the pot life can be improved.

According to the manufacturing apparatus according to the invention of claim (2), the cavity and the belt injection opening are formed simply by overlapping the mold members, so that the round belt manufacturing operation can be simplified.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention, with Figure 1 being a vertical cross-sectional view showing the state in which the mold is attached to the shaft, and Figure 2 being a vertical cross-sectional view showing the state where the mold is attached to the shaft.
The figure is a vertical cross-sectional view of the cavity surrounding area with the mold disassembled, FIG. 3 is an overall view of the belt manufacturing apparatus, and FIG. 4 is a vertical cross-sectional perspective view of the belt body removed from the mold. 1... Belt manufacturing device 4... Mold 5... Lower die 6... Middle die 7... Upper die 10... Opening 6 JP-A-3-211042 (7)

Claims (2)

[Claims] (1) A method for manufacturing a rubber round belt, etc., which has a cavity with a circular cross section extending in the circumferential direction, and an opening for injecting belt material that communicates with the cavity in a divided portion of the inner peripheral surface. A ring-shaped mold formed around the entire circumference is prepared, and a fluid curable belt material is poured into the cavity through the opening by centrifugal force caused by rotation of the mold around the center of the ring, and A method for manufacturing round belts, etc., characterized by curing while maintaining the rotation of a mold. (2) Consisting of a plurality of ring-shaped mold members stacked on top of each other,
A cavity with a circular cross section extending in the circumferential direction is formed between the mold members to be superposed, and an opening for injecting belt material communicating with the cavity is provided around the entire circumference at the overlapping part of the inner peripheral surface of the mold member. a formed mold; and a driving means for driving the mold to rotate around the center of the ring so that a fluid curable belt material flows into the cavity from the opening by centrifugal force. Manufacturing equipment for round belts, etc., featuring: