JPH0226648Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a mold used when injecting rubber between an inner metal ring and an outer metal ring. The present invention relates to a molding die for rubber injection suitable for molding belt pulleys and the like in which a rubber annular body is disposed.

Conventionally, this type of mold for injecting rubber between an inner metal ring and an outer metal ring has an inner metal ring 4 and an inner metal ring 4 in an annular recess 3b of a lower mold 3, as shown in FIGS. The outer metal ring 5 is set at a predetermined interval, and the mold 1 is
is closed, and a rubber 6 is inserted between the inner metal ring 4 and the outer metal ring 5.
It was intended to be injected with In addition, upper mold 2, lower mold 3
Annular convex portions 2a, 3a provided respectively in
is provided to prevent the rubber 6 from peeling off during use. In consideration of damage to the mold 1 due to variations in the width dimension a of the inner and outer metal rings 4 and 5, the width dimension b of the lower mold recess 3b is
The width was set to be a plus point than the maximum width dimension a.

Therefore, when the inner and outer metal rings 4 and 5 are set and the mold 1 is closed, a gap h is generated between the mold 1 and the inner and outer metal rings 4 and 5, and the rubber 6 is filled into this gap h during molding. easily rotated, and there was a risk that burrs would be formed on the upper or lower surface of the outer circumferential edge of the inner metal ring 4 and the upper or lower surface of the inner circumferential edge of the outer metal ring 5. For this reason, after the molded product is taken out from the mold 1, finishing work such as deburring may be required.

This invention solves the above-mentioned problems, absorbs variations in width dimensions between the inner and outer metal rings, does not generate burrs, and eliminates the need for finishing work to remove burrs after taking out the molded product, improving productivity. The purpose is to provide injection molds.

The gist of this invention is a mold used when an outer metal ring is set outside an inner metal ring and rubber is injected between the inner metal ring and the outer metal ring. an upper mold having a seal part that comes into contact with the upper edge surface of the rubber side of each to prevent the rubber from flowing out; and a seal part that comes into contact with the lower edge surface of the rubber side of the inner and outer metal rings to prevent the rubber from flowing out. The molding die for rubber injection is characterized in that it further comprises a lower mold in which a first core and a second core are provided, each of which has a pressing means for pressing the mold in the closing direction.

An embodiment of this invention will be described below with reference to figures.

FIG. 3 is a sectional view of a rubber injection mold showing an embodiment of this invention, and FIG. 4 is an enlarged view of a portion of FIG. 3.

The rubber injection mold 11 of the embodiment has an upper mold 12
and a lower mold 13 having a first core 17 and a second core 18.

The upper die 12 is provided with an annular protrusion 12a for preventing the rubber 16 from peeling off during use, similar to the conventional one, and the outer lower surface and inner lower surface in the vicinity of the protrusion 12a taper away from the protrusion 12a. This convex portion 12 is formed in a concave shape.
Narrow seal portions 12b, 12c in which the outer lower surface and inner lower surface in the vicinity of a contact the upper surface of the inner peripheral edge of the outer metal ring 15 and the upper surface of the outer peripheral edge of the inner metal ring 14, respectively.
becomes.

The first core 17 provided in the lower mold 13 has an approximately annular groove 17a formed at the upper end of the outer periphery in which the inner metal ring 14 can be set and has a space in which rubber 16 can be injected around the outer periphery of the inner metal ring 14. The annular groove 17a has a cylindrical shape, and an annular protrusion 17b is formed on the outer peripheral edge of the bottom surface of the annular groove 17a to prevent the rubber 16 from peeling off when in use. The inner side of the bottom near the convex portion 17a forms a narrow seal portion 17c that comes into contact with the lower surface of the outer peripheral edge of the inner metal ring 14. In addition, the first core 1
7 At the bottom, there is a guide pin 1 that can slide inside the lower mold 13.
9 is fixed in the vertical direction, and the first core 17 is attached to the mold 1.
A disc spring 21 is disposed between the first core 17 and the lower mold 13 around the guide pin 19 as a pressing means for pressing in the closing direction (upward direction) of the guide pin 19 .

The second core 18 provided in the lower mold 13 is a substantially annular body that contacts the outer circumferential surface of the first core 17, and has an annular groove 18a in which the outer metal ring 15 can be set at the upper end of the inner circumference. The bottom surface of the groove 18a is formed to be concave in a tapered shape from the outer periphery toward the inside,
The inner circumferential edge of the bottom surface of the annular groove 18a forms a narrow seal portion 18b that comes into contact with the lower surface of the inner circumferential edge of the outer metal ring 15. Further, a lower mold 13 is placed on the lower part of the second core 18 so that the second core 18 is evenly pressed by a pressing means to be described later.
A necessary number of guide pins 20 that are slidable within the mold are fixed in the vertical direction, and disc springs 22 are used as pressing means for pressing the second core 18 in the closing direction (upward) of the mold 11, respectively. It is arranged between the surrounding second core 18 and the lower mold 13.

Note that the upper mold 12 has an inner metal ring 14 and an outer metal ring 1.
A sprue, a gate, etc. are provided so that the rubber 16 can be injected between the rubber 16 and the rubber 16.

Therefore, when the inner metal ring 14 and the outer metal ring 15 are set at predetermined positions of the first core 17 and the second core 18 and the mold 11 is closed, the first core 17 and the second core 18 are closed. Disc springs 21 and 22 are provided at the bottom to press the mold 11 in the closing direction (upward), so even if there is variation in the width dimension a of the inner and outer metal rings 14 and 15, the variation can be absorbed. Upper mold 12, first core 17, and second core 1
8, respectively seal portions 12b, 12c, 17c,
and 18b are pressed against the upper and lower surfaces of the outer circumferential edge of the inner metal ring 14 and the upper and lower surfaces of the inner circumferential edge of the outer metal ring 15, and even if the rubber 16 is then injected, the upper and lower surfaces of the outer circumferential edge of the inner metal ring 14 and the outer metal ring 15 Rubber 1 on the top and bottom of the inner periphery
6 will not rotate and no burrs will occur.

Although the rubber injection mold 11 of the embodiment is shown with its opening/closing direction being in the vertical direction, it is of course possible to have the same effect even if it is placed horizontally and opened/closed in the horizontal direction.

In addition, although the figure shows an example in which disc springs 21 and 22 are used as the pressing means for the first core 17 and the second core 18, it is of course possible to use a coil spring instead of a disc spring. It is also possible to configure the second core to be pressed by a cylinder using hydraulic pressure.

Furthermore, although the illustrated example shows an annular protrusion 17b provided on the first core 17 in order to prevent the rubber 16 from peeling off during use, it is also possible to provide it on the outer periphery of the second core 18. Therefore, unless prevention of peeling is taken into consideration, the protrusions 12a and 17b may not be formed.

In addition, in the illustrated example, the seal portions 12b and 12 of the upper die 12, the first core 17, and the second core 18, respectively.
Inner metal ring 14
Tapered upper and lower surfaces are concave on the inner circumferential side, outer metal ring 15
When using a tapered structure in which the upper and lower surfaces are concave on the outer circumferential side, the seal portion 12
The circumferences of b, 12c, 17c and 18b may be formed flat without being tapered.

This idea has the above structure and function,
When the inner and outer metal rings are set and the mold is closed, any variation in width between the inner and outer metal rings is absorbed, and the upper and lower surfaces of the outer periphery of the inner metal ring and the upper and lower surfaces of the inner periphery of the outer metal ring are covered with the upper mold. , the first core, and the second core are pressed into contact with each other, so even if rubber is subsequently injected between the inner and outer metal rings, the upper and lower surfaces of the outer periphery of the inner metal ring and the inside of the outer metal ring The rubber does not rotate around the upper and lower surfaces of the periphery, so no burrs are generated, eliminating the need for finishing work to remove burrs after taking out the molded product, and there are no burrs inside the mold, eliminating the need to clean the mold after each molding. This has the effect of improving productivity.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional rubber injection mold.
FIG. 2 is an enlarged view of a portion of FIG. 1, and FIG. 3 is a sectional view of a mold for rubber injection showing an embodiment of this invention.
FIG. 4 is an enlarged view of a portion of FIG. 3. 1, 11... Molding mold for rubber injection, 2, 12...
...Upper mold, 12b, 12c...Seal part, 3, 13
...Lower mold, 4,14...Inner metal ring, 5,15...
Outer metal ring, 6, 16...Rubber, 17...First core, 17a...Annular groove, 17c...Seal portion, 1
8... Second core, 18a... Annular groove, 18b...
Seal portion, 21, 22... (pressing means) disc spring.

Claims (1)

[Scope of utility model registration request] A mold used when an outer metal ring is set on the outside of an inner metal ring and rubber is injected between the inner metal ring and the outer metal ring, and the mold includes an upper mold and a first middle ring. and a lower mold including a second core and a second core, and the upper mold is formed with a seal portion that comes into contact with the upper surface of the outer peripheral edge of the inner metal ring and the upper surface of the inner peripheral edge of the outer metal ring when the mold is closed. , the first core is formed with a seal portion that comes into contact with the lower surface of the outer peripheral edge of the inner metal ring when the mold is closed, and the second core is formed with a seal portion that contacts the lower surface of the inner peripheral edge of the outer metal ring when the mold is closed. For rubber injection, a sealing portion is formed in contact with the mold, and the first core and the second core are further provided with pressing means for pressing in the closing direction of the mold when the mold is closed. Molding mold.