JPS5833443A - Preparation of toothed belt - Google Patents

Abstract

PURPOSE:To prepare a high quality toothed belt, by a method wherein a preliminarily fabricated reinforcing fabric with a tooth shaped mold is correctly arranged along the tooth part of an inner metal mold and a liquid resin (a polyurethane elastomer) is thereafter injected to carry out molding processing. CONSTITUTION:Both side parts of a reinforcing plate with a tooth shaped mold obtained by molding a reinforcing plate impregnated with a liquid resin are filled with a urethane foam 5 to form a reinforcing fabric 4b with a connecting segments. In the next stage, the above described reinforcing fabric 4b is wound around a cylinderical inner metal mold 12 in an endless form while inlaid with tooth shaped grooves 13. Subsequently, a rope tensile body 15 are spirally wound around the outer periphery of the reinforcing fabric 4b and a cylindrical outer metal mold (not shown in a drawing) is concentrically attached to inject a liquid resin into the formed gap part and to cure the same therein. The obtained molded body is cut in round slices at a predetermined width to obtain a toothed belt.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a polyurethane toothed belt whose toothed surfaces are covered with a reinforcing cloth.

In particular, by accurately attaching the reinforcing cloth to the tooth profile surface of the toothed belt during the belt manufacturing process, we can eliminate tooth base cracks that frequently occur in conventional seed belts! In fact, the belt life is increased by preventing this, and by forming accurate belt teeth, smooth belt driving can be achieved.

Conventionally, the manufacturing method for polyflex toothed belts has been to endlessly wrap a reinforcing cloth around the outer circumferential surface of a cylindrical inner mold that has a plurality of tooth grooves in the axial direction of the outer circumferential surface, or to wrap the reinforcing cloth around the inner mold. The rope is wound endlessly along the tooth grooves, and the rope tensile body is spirally wound on top of it.A cylindrical outer mold is then set concentrically on the outside of this inner mold, and the inner mold and Liquid urethane elastomer is injected into the gap between it and the outer mold, and the urethane elastomer is passed between the tensile members and filled into the tooth grooves of the inner mold to form the teeth of the belt, and the tensile member is embedded. to form a belt tension portion at the same time,
After the flexible elastomer hardens, the belt molded body is removed from the mold, and the belt molded body is cut into rings of a predetermined width in the circumferential direction.
The most common manufacturing method is to obtain multiple toothed belts, but the reinforcing fabric may become misaligned when winding the rope tension member or filling the teeth with liquid urethane elastomer. Air bubbles may occur on the surface of the belt teeth, wrinkles or sag may occur in the reinforcing cloth on the surface of the teeth, and uniform and accurate shaping of the belt tooth profile is the most important area for smooth belt drive. had many problems.

The present invention aims to prevent the failure of the accurate forming operation of the belt teeth caused by the disorder of the reinforcing cloth, and the reinforcing cloth is molded to form a reinforcing cloth with a tooth pattern in advance, and then this is The structure is precisely positioned along the teeth of the inner mold.

Next, a method for manufacturing a polyflex toothed belt according to the present invention will be explained with reference to the drawings.

First, as the first step, as illustrated in FIG. A reinforcing fabric (4) made of stretchable canvas, non-woven fabric, knitted fabric, etc. woven with shrunk nylon warp and normal nylon weft is used, especially reinforcing fabric (4).
If 4) is a stretchable canvas, the stretch direction of the canvas is arranged perpendicular to the tooth profile (3) (3) of the lower molding board (2). Apply polyurethane nystomer to the reinforcing cloth (4) on all songs,
This reinforcing cloth (4) is held between upper and lower molding plates (1) and (2) and heated under pressure from the outside for a predetermined period of time to harden the shape-retaining polyurethane nidistomer that has passed through the reinforcing cloth (4). A reinforcing cloth (4a) with a tooth pattern is obtained (see FIG. 2).

The next second step is to strengthen and fix the tooth groove portions at both ends of the reinforcing fabric with tooth profile (4a) with tooth profile connecting pieces, and to further improve the shape retention effect of the tooth profile reinforcing fabric, as shown in Fig. 3. As shown in the figure, remove the upper plate (1) of the molding board, and attach both ends of the lower molding board (2) with the tooth-shaped reinforcing cloth still attached using a pair of end plates (6) (6). Bolts to the lower molding board (2) (
7), etc., and place a pre-formed tooth-shaped Frethane rod-shaped body (8) as shown in Fig. 4 in the center of the tooth groove of the lower molding plate (2), i.e. Each reinforcing cloth with a tooth profile (4a) is fitted into the center part thereof, thereby creating a gap (9) between the end plate (6) and the end face of the fitted tooth profile rod (8) (Fig. 8). ), then polyurethane distomer is injected into this void (9), the clay plate 00 is placed on the lower molding board (2), and this is heated under pressure from the outside to form the void (9) K. After curing the injected r-lastomer, remove the top plate (10) and the tooth-shaped urethane rod-shaped body (8) in sequence, and attach the grooves at both ends shown in Fig. 5 to the urethane tooth-shaped connecting pieces (5) (5). The tooth-shaped reinforcing cloth (41) with connecting piece which is fixed and shape-retaining is placed on the lower molding plate (2).
).

As a third step, the tooth-shaped reinforcing cloth (4b) is
As shown in the figure, a cylindrical inner mold α'4 having a large number of tooth-shaped grooves in the axial direction on the entire outer circumference is coated with a thin layer of polyurethane nystomer sprayed in advance on the tooth-shaped groove 03 portion of the inner mold. The tooth profile portions of the reinforcing cloth (4b) are matched with the tooth profile grooves 03 of the inner mold (2), and the tooth profile connecting pieces (5) (5) formed at both ends of the reinforcing cloth (4b) are inserted into the inner mold together with the reinforcing cloth. It is wrapped endlessly around the circumferential surface of the inner mold while being strongly pushed into the tooth-shaped groove 03 of the mold.

6') In the invention, the tooth-shaped connecting piece (5) of the reinforcing cloth (
Since the method of pushing 5) into the groove of the inner mold is adopted, the reinforcing cloth (4b) can be easily fixed to the outer part of the inner mold Q44, and its fixation is strong and reliable.

As the fourth step, a low elongation, high strength material such as steel wire, Tetron (trade name), nylon fiber, etc. Attach the rope tension body OQ to the spiral spring.

Thus, in the fifth step, reinforcing cloth with a tooth pattern and a connecting piece (
4b) A cylindrical outer mold (not shown) is set concentrically outside the inner mold with a rope tensile body wrapped around the outer peripheral surface of the mold. Liquid urethane elastomer is injected into the gap formed by both molds, the elastomer fills the gap, and the teeth and tension parts of the belt are filled and molded. Vulcanization hardening progresses by heating for a predetermined period of time, creating a wide width. A toothed belt molded body is formed.

In the final sixth step, the thus obtained toothed belt molded body is removed from both the inner and outer molds, cut into rings with a predetermined width in the circumferential direction, and the entire surface of the toothed part shown in Fig. 7 is covered with reinforcing cloth. A precisely coated polyurethane toothed belt 0Q is obtained.

The present invention is intended to strengthen the belt teeth by accurately covering the entire surface of the teeth with a reinforcing cloth. Accurately fixing and covering the reinforcing cloth at a predetermined position has been accompanied by many difficulties. In the present invention, the reinforcing cloth is coated with polyurethane elastomer and molded using heat and pressure.The reinforcing cloth with tooth-shaped shapes is created in advance, and the grooves at both ends of this reinforcing cloth are connected to the urethane tooth-shaped shapes. When the reinforcing cloth with connecting piece is firmly wrapped around the grooved circumferential surface of the inner mold in an interlocking state, the toothed connecting piece is pressed and the inner mold is tightened. Since it can be stably attached to the mold surface, it can be used to prevent the reinforcing fabric from shifting, wrinkling, or bending during the subsequent wrapping of the rope tensile material or during the injection of liquid urethane elastomer into the belt teeth. The cause of fatal defects can be completely eliminated, and the reinforcing AJ is accurately and firmly fixed over the entire surface of the belt's teeth, so there will be no tooth root clutter in future belts. Moreover, a belt in a good meshing state can be maintained throughout the cutting period.

[Brief explanation of the drawing]

Figure 1 is a partial perspective view of the molding board, Figure 2 is tooth J cedar i1,1
7 (-J) A partial perspective view of the reinforcing fabric, Figure 3 shows the connecting piece.
1) A perspective view showing the forming process of reinforcing cloth with W, FIG. 4 is a perspective view of a tooth-shaped urethane rod, FIG. Figure 7 shows -814 of the toothed belt obtained by implementing this invention.
FIG. In the figure, (1), (2) beams, ■ molding board, (3) tooth profile,
(4) is reinforcing cloth, (4a) is reinforcing cloth with tooth pattern, (4b
) has one reinforcing cloth with H-, (5) (5) has a tooth-shaped connecting piece, (one is F) No. 4? , 惺1. (13 indicates the tooth groove, and α indicates the rope tension member. Fig. 4b

Claims (1)

[Claims] (1) A reinforcing cloth coated with polyurethane nystomer is sandwiched between a pair of molding plates, heated and pressed to form a reinforcing cloth with a toothed shape, and then the grooves at both ends of this reinforcing cloth are made into toothed connecting pieces. The reinforcing cloth with the tooth-shaped connecting piece is meshed around a cylindrical inner mold in which a group of tooth-shaped grooves are carved in the axial direction of the circumferential surface and a thin layer of polyurethane distomer is adhered to the inside of the groove. After pressure winding and spirally wrapping a rope tensile material on its surface, outer molds are assembled concentrically, and liquid urethane elastomer is injected between both molds and cured to produce a belt molded product. A method for manufacturing toothed belts that are cut into rings.