Rubber splice molding method and mold

Abstract

To provide a rubber splice molding method for connecting a pair of preformed rubber rods with their tips in an unvulcanized state, while vulcanizing them.SOLUTION: The method includes butting unvulcanized tips of preformed rubber rods 1 and 2 against each other, forming burrs 15 projecting on both sides S5 and S5, and vulcanizing them.SELECTED DRAWING: Figure 6

Description

Background Art

[0001] The present invention relates to a rubber joining molding method and a mold.

Technical Field

[0002] Conventionally, as shown in FIGS. 15 to 21, as a rubber joining molding method, with the end faces 43, 43 of the tips of a pair of preformed rubber rod-like bodies 42, 42 whose tips 41 are in an unvulcanized state (including a semi-vulcanized state) abutted against each other, they are vulcanized (by heating and pressing) and joined. This method is known (see Patent Document 1).

[0003] In FIGS. 15 to 17, in the lower mold 44, with a single product groove 45 as the center, two escape grooves 46, 46 are recessed in parallel therewith. Into the product groove 45 of this lower mold 44, a pair of the preformed rubber rod-like bodies 42 are fitted as shown in FIG. 18. By the upper mold 48, as shown in FIGS. 19 and 21, it is pressed so that both end faces 43, 43 are in contact with each other, and heated and pressed (that is, press molding is performed).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the rubber rod-like body (product) 49 obtained by the above-described conventional molding method, there has been a problem that a defective joint portion 50 as shown in FIG. 21 occurs. Therefore, the present inventor repeatedly conducted experiments and the like to investigate the cause of the occurrence of such a defective joint portion 50, and as a result, the following has been found. That is, as shown in FIGS. 19 and 20, the upper mold 48 is moved in the direction of arrow N 48As shown, when pressing while approaching the lower mold 44, the rubber rod-shaped body 42 causes a large flow toward the side of the outer end 45A within the product groove 45 where the outer end 45A is in an open state (open-mouthed state), as indicated by arrow F 42 As a result, it has been found that a large flow toward the side of the outer end 45A occurs, and the end faces 43, 43 cannot be pressed together strongly enough.

[0006] In addition, as shown in Fig. 20, when the upper mold 48 is pressed while approaching the lower mold 44 as indicated by arrow N 48 As shown, when pressing while approaching the lower mold 44, the flow into both relief grooves 46, 46 (refer to arrow F 46 ) is small. Therefore, an object of the present invention is to provide a rubber joining and molding method that solves the above-described conventional problems and can firmly and reliably connect the unvulcanized tips of preformed rubber rod-shaped bodies by vulcanization, and a mold therefor.

Means for Solving the Problem

[0007] Therefore, in the rubber joining and molding method of butting the end faces of the tips of a pair of preformed rubber rod-shaped bodies at least at the tips in an unvulcanized state and vulcanizing and connecting them by heating and pressing; a rubber joining and molding method in which a thin plate-like burr is formed in a protruding shape from the butting position of the end faces of the above tips to both sides or one side.

[0008] In addition, in the mold used for rubber joining and molding, which has a product molding groove in the center and relief grooves in parallel on both the left and right sides; corresponding to the longitudinal position of the rod-shaped body tip butting portion where the tips of a pair of preformed rubber rod-shaped bodies at least at the tips in an unvulcanized state are butted together; a substantially rectangular burr forming recess is formed in the above product molding groove. In addition, a communication small groove with a minute cross-sectional area that connects and communicates the above burr forming recess and the above relief groove is formed. In addition, the above communication small groove is disposed at the center of the inner side of the substantially rectangular burr forming recess. In addition, the above communication small groove is disposed at the inner corner of the substantially rectangular burr forming recess.

[0009] In addition, in the rubber joining and molding method of the present invention, while clip projecting pieces for attaching other members are provided projecting at the intermediate part in the longitudinal direction, the end faces of the tips of the preformed rubber rod-shaped bodies with both tips in an unvulcanized state are butted against each other in sequence, and are vulcanized by heating and pressing to be connected in a closed ring shape; it is a rubber joining and molding method in which a new clip projecting piece corresponding to the connection position is formed so as to project laterally from the butting position of the end faces of the above-mentioned tips.

Effects of the Invention

[0010] According to the rubber joining and molding method of the present invention, the unvulcanized rubber at the tips of the preformed rubber rod-shaped bodies surely and strongly collides with each other and becomes in a state of being pressure-bonded. To explain repeatedly, the raw rubber at the tips of the preformed rubber rod-shaped bodies flows in the product groove (of the mold) at a sufficient high speed while forming thin plate-like burrs projecting to both sides (or one side). Therefore, the end faces of the tips of the pair of rubber rod-shaped bodies collide with each other and are butted together, so the subsequent vulcanization (by heating and pressing) of the butted part is surely performed, and the pair of rubber rod-shaped bodies can be firmly integrated (connected).

[0011] Also, according to the mold of the present invention, since a substantially rectangular burr-forming recessed part is formed in the product molding groove, the raw rubber at the tips of the preformed rubber rod-shaped bodies flows in the product molding groove at a sufficient high speed while forming thin plate-like burrs projecting laterally. Therefore, the end faces of the tips of the pair of rubber rod-shaped bodies collide with each other and are surely butted together. Thus, the subsequent vulcanization (by heating and pressing) is surely performed, and the pair of rubber rod-shaped bodies can be firmly integrated (connected).

[0012] Also, in the present invention (claim 6), since it is a rubber joining and molding method in which a new clip projecting piece corresponding to the connection position is formed so as to project laterally from the butting position of the end faces of the above-mentioned tips, the raw rubber flows in the product molding groove (of the mold) at a sufficient high speed while (newly) forming the new clip projecting piece. Therefore, the end faces of the pair of preformed rubber rod-like bodies (unvulcanized) collide with each other and abut against each other. Therefore, subsequent vulcanization (by heating and pressurization) is surely performed, and they are firmly connected and integrated. Moreover, new clip protrusions for attaching other members can be (newly) formed, achieving a two-for-one effect.

Brief Description of the Drawings

[0013]

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Embodiments for Carrying Out the Invention

[0014] Hereinafter, the present invention will be described in detail based on the illustrated embodiments. In FIGS. 1 to 7, a lower mold 4 and an upper mold 8 used in a rubber joining molding method are illustrated.

[0015] In the rubber joining molding method, the end faces 11 and 12 of the tips 1A and 2A of a pair of preformed rubber rod-like bodies 1 and 2, at least the tips 1A and 2A of which are in an unvulcanized state, are butted against each other (see FIG. 4). Then, as shown in FIG. 5, the heated upper mold 8 (as a press mold) is pressed as indicated by the arrow F 8 in this way. By continuing this pressing state for a predetermined time, the unvulcanized tips 1A and 2A (and other unvulcanized parts if any) are vulcanized by heating and pressing, and the both end faces 11 and 12 are integrally connected. In the illustration shown in FIG. 4, one of the preformed rubber rod-like bodies 1 has only the tip 1A unvulcanized, and the remaining part 1C is shown as being vulcanized. The other preformed rubber rod-like body 2 is illustrated as having not only the tip 2A but also the whole being unvulcanized. (In FIG. 4, the vulcanized state is shown by a large number of small dots.)

[0016] Next, the mold used for rubber joint molding will be specifically described. As shown in FIGS. 1 to 7, the mold has a product molding groove 5 in the center, and has escape grooves 6, 6 in parallel on the left and right thereof. At least, the end faces 11, 12 of the tips 1A, 2A of the pair of preformed rubber rod-like bodies 1, 2 whose tips 1A, 2A are in an unvulcanized state are butted against each other. Corresponding to the longitudinal position of the rod-like body tip butting portion 30, a burr formation concave portion 9 having a substantially rectangular shape in plan view is formed in the product molding groove 5. (This burr formation concave portion 9 can also be referred to as a dummy formation concave portion 9.)

[0017] Also, as shown in FIGS. 1, 6, and 7, a communication small groove 10 having a minute cross-sectional area for connecting and communicating the burr formation concave portion 9 and the escape groove 6 is formed. This communication small groove 10 is a small groove having a width dimension of 3 mm to 8 mm and a depth of about 0.05 mm to 0.3 mm. Also, in the embodiment shown in FIGS. 1 and 6, this communication small groove 10 is disposed at the center of the inner side 19 of the substantially rectangular burr formation concave portion 9. In addition, as shown in FIG. 9, it is also possible to dispose the communication small groove 10 at the inner corner portion 20 of the substantially rectangular burr (dummy) formation concave portion 9. Although not shown, in FIG. 9, the communication small groove 10 is disposed only at one inner corner portion 20, but it may be disposed at both inner corner portions 20, 20.

[0018] Next, the rubber joint molding method in the present invention will be described. In FIG. 4, a rubber joint molding method in which the tips 1A, 2A of a pair of preformed rubber rod-like bodies 1, 2 whose tips 1A, 2A are at least in an unvulcanized state are butted against each other, and as shown in FIG. 5, the upper mold 8 is pressed and vulcanized and connected by heating and pressurization is conventionally known.

[0019] In the present invention, from the butting position Z of the end faces 11, 12 of the tips 1A, 2A, both sides S 5 , S 5A manufacturing method for forming, in a protruding shape, thin plate-like burrs 15, 15 (which may also be referred to as dummies or dummy parts) (see FIGS. 5, 6, and 7). Furthermore, specifically in detail, as shown in FIGS. 5, 6, and 7, when the preformed rubber rod-like bodies 1 and 2 are pressed by the upper die 8 in the direction of arrow F 8 the rubber rod-like bodies 1 and 2, when being pressed, (compared with the arrow F in the conventional example shown in FIG. 19) flow only a little (do not escape) toward the side of the outer end 5A of the product forming groove 5, as indicated by arrows F 42 1 ,F 2 . That is, the end faces 11 and 12 of the preformed rubber rod-like bodies 1 and 2 that abut against each other are pressed together sufficiently strongly. Furthermore, since the flow of the rubber in the longitudinal direction F 1 ,F 2 is suppressed, the dimensional accuracy is excellent. Moreover, as shown in FIGS. 6 and 7, from the abutting position Z of the end faces 11 and 12 of the preformed rubber rod-like bodies 1 and 2, unvulcanized rubber flows out toward the sides S 5 ,S 5 , and the end faces 11 and 12 from which impurities (gases, etc.) have been removed are abutted against each other.

[0020] FIG. 8(A) shows an intermediate product 22 obtained by the die and manufacturing method shown in FIGS. 1 to 7 (described above), in a state where unnecessary protruding parts 17 such as burrs 15 are protruding. Therefore, as shown in FIG. 8(B), if this unnecessary protruding part 17 is cut and removed, a gasket or sealing material with a large circumferential length as a rubber product 25 can be obtained. In FIG. 8(A), it may also be possible to cut at the part indicated by X-X and leave only the rectangular burr 15. That is, FIG. 13(A) shows the case where the rectangular burr 15 is left in this way.

[0021] Or, as shown in FIG. 8(B), it is also desirable to remove all the rectangular burrs 15. ​Furthermore, in Fig. 13(A), the whole is a simple single annular body (without a branch portion), but as shown in Fig. 13(B), it may also be preferable to continuously provide branch portions 26 that form (separate closed sub-annular portions 24, 24) by means of branch portions 23, 23. It is also desirable that the shape of the closed sub-annular portion 24 be circular, elliptical, polygonal, or the like.

[0022] Although not shown in the drawings, Fig. 13(B) shows the case where all the burrs 15 are cut and removed, but it is also possible to leave the burrs 15. In Figs. 13(A) and 13(B), P indicates the approximate length dimension of the preformed rubber rod-shaped bodies 1 and 2 before connection, and Z indicates the connection (butted) position.

[0023] Next, Figs. 9 to 12 show another embodiment of the mold used for rubber joint molding. (Similar to the aforementioned embodiment,) it has a product molding groove 5 in the center, and on its left and right sides in parallel, there are escape grooves 6, 6. At least the tips 1A, 2A of a pair of preformed rubber rod-shaped bodies 1, 2 in an unvulcanized state correspond to the longitudinal position of the rod-shaped body tip butting portion 30 where the tips 1A, 2A are butted. In the product molding groove 5, a burr-forming concave portion 9 having a substantially rectangular shape in plan view is formed only on one side in the left-right direction.

[0024] Also, an example is shown where a communication small groove 10 having a minute cross-sectional area for communicating and connecting a single burr-forming concave portion 9 and the escape groove 6 is disposed at one of the inner corner portions 20 of the burr-forming concave portion 9. This communication small groove 10 is a small groove having a width dimension of 3 mm to 8 mm and a depth of about 0.05 mm to 0.3 mm. Although not shown in the drawings, communication small grooves 10 may be disposed at both inner corner portions 20, 20. Alternatively, (as in the embodiment shown in Fig. 6,) it is also possible to dispose the communication small groove 10 at the center of the inner side 19 of the concave portion 9.

[0025] Next, another embodiment of the present invention shown in Fig. 14 will be described. Figure 14(B) shows a rubber molded product 36 such as a gasket or seal with a long circumference - for example, 2000 mm or more - manufactured by the rubber joining molding method, which is fixed (attached) along the peripheral edge of a large-diameter mounting hole (hole) of another member. In particular, on the peripheral edge of such a large-diameter mounting hole (hole), engaging protrusions (such as mounting pins) are arranged at a predetermined pitch (not shown in the figure). Correspondingly, a large number of clip protrusion pieces 13 with small holes are arranged on the rubber molded product 36.

[0026] Hereinafter, a method for manufacturing such a rubber molded product 36 by rubber joining molding will be described in detail. In Figure 14(A), a plurality of - five in the illustrated example - preformed rubber rod-like bodies 3 are shown. Both ends 3A, 3A of each preformed rubber rod-like body 3 are in an unvulcanized state, and moreover, the intermediate part is vulcanized, and a plurality of clip protrusion pieces 13... for attaching to other members project (in advance). That is, a plurality of preformed rubber rod-like bodies 3 in which clip protrusion pieces 13... for attaching to other members project in advance at the intermediate part in the longitudinal direction and both ends 3A, 3A are in an unvulcanized state are prepared in advance. The end faces 11, 12 of the tips 3A of these rod-like bodies 3, 3 are sequentially butted together and vulcanized by heating and pressing to form a closed-loop rubber molded product 36 as shown in Figure 14(B).

[0027] In Figure 14(B), Z indicates the butted part (position). In this way, a new clip protrusion piece 13N is formed to protrude laterally from the butting position Z of the end faces 11, 12 of the tips 3A, 3A - that is, to protrude laterally in the same direction as the existing clip protrusion piece (old clip protrusion piece) 13. As is clear from Figure 14(B) and the above description, for the method of forming the new clip protrusion piece 13N, the mold and manufacturing method as described in Figures 9 to 12 can be applied.

[0028] As described in detail above, in the rubber joining and molding method of abutting the end faces 11, 12 of the tips 1A, 2A of a pair of preformed rubber rod-like bodies 1, 2 in which at least the tips 1A, 2A are in an unvulcanized state, and vulcanizing and connecting them by heating and pressing; from the abutting position Z of the end faces 11, 12 of the tips 1A, 2A, to both sides S 5 , S 5 or one side S 5 to form a protruding thin plate-like burr 15, so that the unvulcanized rubber at the tips 1A, 2A of the preformed rubber rod-like bodies 1, 2 strongly collides with each other and is in a state of being press-connected. That is, the tips 1A, 2A of the preformed rubber rod-like bodies 1, 2 are on both sides S 5 , S 5 (see Fig. 7) or one side S 5 (see Fig. 12) to flow in the product forming groove 5 at a sufficient speed so as to form a protruding thin plate-like burr 15. The end faces 11, 12 of the tips 1A, 2A strongly collide with each other and are abutted, so that they are surely and firmly integrated by subsequent vulcanization (by heating and pressing). That is, the end faces 11, 12 of the tips 1A, 2A of the rod-like bodies 1, 2 are firmly integrally connected.

[0029] Further, the mold according to the present invention has a product forming groove 5 in the center and has escape grooves 6, 6 in parallel on both the left and right sides, and is a mold used for rubber joining and molding; at least the tips 1A, 2A of a pair of preformed rubber rod-like bodies 1, 2 in an unvulcanized state correspond to the longitudinal position of the rod-like body tip abutting portion 30 where the tips 1A, 2A are abutted; in the product forming groove 5, a substantially rectangular burr forming recess 9 is formed. Therefore, the raw rubber at the tips 1A, 2A of the preformed rubber rod-like bodies 1, 2 flows in the product forming groove 5 at a sufficient high speed while forming a thin plate-like burr 15 protruding laterally. Therefore, the end faces 11, 12 of the tips of the pair of rubber rod-like bodies 1, 2 collide with each other and are surely abutted. Therefore, subsequent vulcanization (by heating and pressing) is surely performed, and the pair of rubber rod-like bodies 1, 2 can be firmly integrated (connected).

[0030] In addition, in the mold, since a communication small groove 10 with a minute cross-sectional area that communicatively connects the burr formation concave portion 9 and the relief groove 6 is formed, the gas / air inside the burr formation concave portion 9 is immediately expelled to the relief groove 6, and rubber immediately flows into and fills the burr formation concave portion 9. Moreover, an appropriate internal pressure can be maintained in the burr formation concave portion 9.

[0031] In addition, since the communication small groove 10 is disposed at the center of the back side 19 of the substantially rectangular burr formation concave portion 9, the machining (formation) of the communication small groove 10 is easy, and the preformed rubber rod-like bodies 1 and 2 easily flow at an equal speed. In addition, since the communication small groove 10 is disposed at the inner corner portion 20 of the substantially rectangular burr formation concave portion 9, the setting of the machining position of the communication small groove 10 becomes easy.

[0032] In addition, in a rubber joining molding method in which a clip projection piece 13 for attaching other members projects at a longitudinal intermediate portion, and the end faces 11 and 12 of the tips 3A of the preformed rubber rod-like bodies 3 and 3 whose both tips 3A are in an unvulcanized state are sequentially butted against each other and vulcanized by heating and pressing to be connected in a closed annular shape; since it is a method of forming a new clip projection piece 13N that protrudes laterally from the butting position Z of the end faces 11 and 12 of the tips 3A and corresponds to the connection position, as shown in FIG. 14(B), the new clip projection piece 13N can be formed extremely easily and surely in accordance with the interval (pitch) between the original clip projection pieces 13... at an equal pitch in the circumferential direction. Therefore, as exemplified in FIG. 14(B), it is also easily possible to equally arrange the clip projection pieces 13 and 13N over the entire circumference of the rubber molded product 36. Moreover, the connecting portion between the preformed rubber rod-like bodies 3 and 3 has its connection strength improved and high (excellent) dimensional accuracy in the longitudinal direction by forming the new clip projection piece 13N. That is, the high connection strength between the preformed rubber rod-like bodies 1 and 2 described in FIGS. 11 and 12 is obtained as the same action / effect.

Explanation of Reference Numerals

[0033] 1 Preformed rubber rod-like body 1A Tip 2 Preformed rubber rod 2A Tip 3 Preformed rubber rod 3A Tip 5 Product forming groove 6 Relief groove 9 Burr forming recess (dummy forming recess) 10 Communication small groove 11 End face 12 End face 13 Clip projection 13N New clip projection 15 Burr 19 Rear side 20 Rear corner 30 (Rod tip) butting part S 5 Side Z Butting position

Claims

1. In a rubber joining and molding method in which end faces (11) (12) of tips (1A) (2A) of a pair of preformed rubber rod-like bodies (1) (2) with at least the tips (1A) (2A) in an unvulcanized state are abutted against each other and vulcanized and connected by heating and pressing, From the mutual butting position (Z) of the end faces (11)(12) of the above-mentioned tips (1A)(2A), to both sides (S 5 )(S 5 ) or to one side (S 5 ), forming a thin plate-like burr (15) in a protruding shape, A rubber joining and molding method characterized thereby.

2. In a mold used for rubber joining and molding, having a product forming groove (5) in the center and relief grooves (6) (6) in parallel on both the left and right sides, The tips (1A) (2A) of a pair of preformed rubber rod-like bodies (1) (2) with at least the tips (1A) (2A) in an unvulcanized state correspond to the longitudinal position of a rod-like body tip abutting portion (30) where the tips are abutted against each other, A substantially rectangular burr forming recessed portion (9) is formed in the product forming groove (5). A mold characterized thereby.

3. The mold according to claim 2, in which a communication small groove (10) with a minute cross-sectional area for communicating and connecting the burr forming recessed portion (9) and the relief groove (6) is formed.

4. The mold according to claim 3, in which the communication small groove (10) is disposed at the center of the back side (19) of the substantially rectangular burr forming recessed portion (9).

5. The mold according to claim 3, in which the communication small groove (10) is disposed at the back corner portion (20) of the substantially rectangular burr forming recessed portion (9).

6. In a rubber joining and molding method in which clip projecting pieces (13) for attaching other members project at the longitudinal intermediate portion and end faces (11) (12) of tips (3A) of preformed rubber rod-like bodies (3) (3) with both tips (3A) (3A) in an unvulcanized state are sequentially abutted against each other and vulcanized and connected in a closed loop by heating and pressing, From the mutual abutting position (Z) of the end faces (11) (12) of the tips (3A) (3A), a new clip projecting piece (13N) corresponding to the connection position is formed to project laterally. A rubber joining and molding method characterized thereby.

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