JP2005199487A - Venting device of tire vulcanizing mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire vulcanizing mold constituted so as to facilitate processing of high precision with respect to a mold or the like, to effectively prevent the early occurrence of the settling phenomenon, damage or the like of a valve disc pressing spring and to form the earth surface of a molded block as an expected flat smooth surface to also effectively prevent the occurrence of unbalanced abrasion to the block. <P>SOLUTION: In the venting device of the tire vulcanizing mold for vulcanizing and molding a tire having a block pattern, a vent hole 3 is formed corresponding to a block forming position and one valve disc 5 for bringing about the communication and cutting-off of the vent hole 3 and a block forming space 2 and molding the whole of the earth surface of the formed block is arranged and a coil spring for energizing the valve disc 5 in the direction separated from a valve seat 6 is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  This invention enables smooth and sufficient discharge from the vulcanization molding space of the air contained in the vulcanization mold, the gas generated from the green tire, and the like when vulcanizing the green tire. In particular, it is used for vulcanization molding of product tires having a block pattern, and it has excellent durability and can cause unexpected irregularities on the ground contact surface of the block. There is no suggestion of technology.

  For example, as a conventional gas venting device for a vulcanization mold used for vulcanization molding of a heavy duty pneumatic tire having a large contact area of a block, FIG. 4 shows a cross-sectional view and molding for one block formation space. As illustrated in the front view of the surface, the grounding surface of the block formed in the block forming space 51 is identified, and a plurality of, for example, two through the molds are formed in the top wall 52 of the space 51. The vent holes 53 are formed, and at the end of each vent hole 53 on the space 51 side, communication between the vent hole 53 and the block forming space 51 and blocking of the communication are performed. For example, the front dimension is 7 × 4 mm. Some valve bodies 54 are arranged, and each valve body 54 is constantly urged toward the space 51 by a coil spring 55 housed in a vent hole 53.

  In such a gas venting apparatus, when the tread rubber of the tire enters the block forming space 51 as indicated by the phantom line in FIG. For example, air between the tread rubber 56 and the top wall 52 in 51 can be discharged out of the mold through the vent hole 53 under the opening of the valve body 54 based on the action of the coil spring 55. Then, after the tread rubber 56 enters the space 51 until it contacts the valve body 54, the valve body 54 is resisted against the spring force of the coil spring 55 by the valve body pressing force by the tread rubber 56. The seating can prevent the tread rubber 56 from flowing into the vent hole 53.

  However, in this prior art, a plurality of extremely small sized valve bodies 54 are disposed on the top wall 52, and each of the valve bodies 54 is disposed in each small-diameter vent hole 53. Therefore, there is a problem that it is difficult to process the mold or the like with high accuracy, and the coil spring 55 is liable to sag or break.

  In addition, when the green tire is vulcanized, each of the plurality of valve bodies 54 contributes independently to the molding of the ground contact surface portion of the block. Therefore, the entire ground contact surface is made smooth. There is a problem that it is difficult to form a flat flat surface, and there is a high possibility that the block ground surface is worn unevenly.

  The present invention has been made to solve such problems of the prior art, and the object of the present invention is to facilitate high-precision machining of a mold and the like, and to provide a valve body. Effectively prevent the occurrence of premature sag, breakage, etc. of the pressure spring.Furthermore, the ground contact surface of the molded block is made to be a flat and smooth surface as expected, so that uneven wear on the block is generated. It is also an object of the present invention to provide a venting device for a tire vulcanization mold that can be effectively prevented.

  A degassing device for a tire vulcanization mold according to the present invention is for vulcanizing and molding a tire having a block pattern, and forms one or more vent holes corresponding to the formation position of the block. Directly or indirectly with respect to the mold by providing a valve body for forming communication between the vent hole and the block forming space and blocking the communication, and molding almost the entire grounding surface of the formed block. At least one spring member is provided to urge the valve body, which has been prevented from coming off, in a direction away from the valve seat.

  Here, “moulding almost the entire grounding surface of the block to be formed” means that the entire edge of the block grounding surface is molded, and the contour edge of the block grounding surface is endless with a width of, for example, 1 to 2 mm. This includes the case where all of the remaining part of the grounding surface is molded while the shape is left in a streak shape.

  More preferably, in this apparatus, the spring member is a coil spring, and the coil spring is disposed in the enlarged end of the vent hole on the block forming space side.

  In the same way as described in the prior art, the degassing by this apparatus is performed between the valve body and the valve seat in an open posture as the tread rubber enters the block forming space in the vulcanization molding of the green tire. This degassing is performed by the tread rubber contacting the valve body against the valve seat against the selected spring force of the spring member. Since the process is terminated by press-bonding, it is possible to effectively prevent the rubber from protruding and the like while the air, the generated gas and the like enclosed in the block forming space are sufficiently discharged.

  In addition, in this apparatus, since the one valve body is made large in size corresponding to almost the entire block ground surface, the spring member that biases the valve body is also made larger in size. In addition to being able to easily perform processing with a required accuracy with respect to the above, the durability of the spring member can be greatly increased.

  Further, according to this apparatus, since the entire block grounding surface is molded with one valve body, the entire block grounding surface is present in a smooth and flat plane. It is possible to effectively prevent the occurrence of uneven wear or the like on the block due to the unevenness of the block ground surface.

  In this apparatus, when the spring member is a coil spring and the coil spring is disposed in the enlarged end portion of the vent hole on the block forming space side, high-precision machining on the mold is further facilitated. Further, by disposing one or more coil springs having a required size under a sufficient space, the durability of the coil spring can be further enhanced without preventing gas venting.

  FIG. 1 is a sectional view showing an embodiment of the present invention with respect to one block forming space.

  Here, one vent hole 3 is formed corresponding to the block forming space 2 of the vulcanizing mold 1, and the end of the vent hole 3 on the block forming space 2 side is an enlarged end 4. Between the enlarged end portion 4 and the block forming space 2, a single valve body 5 for forming the entire ground contact surface of the block to be formed is disposed.

  The valve body 5 blocks communication between the vent hole 3 and the block forming space 2 in a state in which the valve seat 5 is pressed against the valve seat 6 provided adjacent to the enlarged end portion 4. It functions to provide communication between the two in a separated state.

  Such a valve body 5 has a required posture, for example, by sliding at least one valve rod 7 projecting from the valve body 5 toward the vent hole side, and in the figure, two valve rods 7 to the small hole 8 on the mold side. The valve body 5 can be moved in parallel between the contact position and the separation position with respect to the valve seat 6, and the valve body 5 is provided with, for example, a stopper 9 provided at the tip of the valve stem 7. The abutting limit position from the valve seat 6 is specified by making contact around the small hole 8 in 10.

  Further, here, coil springs 11 are arranged around the respective valve rods 7 in the enlarged end portion 4 of the vent hole 3, and the valve body 5 is separated from the valve seat 6 by these coil springs 11. By energizing, the valve body 5 is normally restrained at the separation limit position from the valve seat 6.

  As described above, the device constructed in this way is effective in smoothly discharging the tread rubber while smoothly discharging the enclosed air, etc., as described above. Can be blocked.

  Further, in this apparatus, the valve body 5 can be made much larger than in the prior art, thereby facilitating various highly accurate processes, and the coil spring 11 can be made larger in spring outer diameter and cord diameter. The durability can be greatly improved below.

  Furthermore, here, by molding the entire block contact surface with the single valve body 5, the possibility of uneven wear of the block contact surface of the product tire can be effectively eliminated.

  FIG. 2 is a cross-sectional view showing another embodiment, in particular, in which the contour dimension of the valve body 4 is somewhat smaller than the ground contact surface contour dimension of the block to be formed, and other configurations are shown in FIG. It is the same as that shown in.

When the gas venting device is configured in this way, the ground contact surface of the block formed by the block forming space is a substantially square central region formed by the valve body 5 as shown in the plan view of the block in FIG. CR and a streak surrounding the central region CR and extending endlessly, for example, having a width in the range of 1 to 2 mm and rising from the central region CR within a maximum height of 1.5 mm Part RU.
When the ground contact surface of the block B is formed in this way, a sufficiently uniform streak-like surrounding portion RU is generated around each block, so that the possibility of occurrence of uneven wear can be advantageously reduced.

従来例をコントロールとした表中の指数値は大きいほどすぐれた結果を示すものとした。
上記表によれば、実施例はいずれも、弁体寸法が大きく、スプリング径を大きくすることができ、また、複数のスプリングを配設することも可能となることにより、耐久性が向上することが明らかである。 Molding of the valve body of the gas venting device having the structure shown in FIG. 1 while the dimensions of the grounding surface of the block to be formed are 15 × 15 mm (W × Lmm), 10 × 25 mm, 20 × 25 mm and 35 × 40 mm. For each of the examples in which the surface dimensions were the same as those of the ground contact surface, the durability test of the coil spring was performed when the outer diameter of the coil spring and the number of coil springs were changed as shown in Table 1. However, the results shown in the bottom row of Table 1 were obtained.
In addition, the conventional example in a table | surface assumed that each one coil spring was applied using the valve body of 7x4mm (WxLmm) so that it might illustrate in FIG.

The index value in the table in which the conventional example was used as a control was shown to be better as the index value was larger.
According to the above table, in all of the examples, the valve body size is large, the spring diameter can be increased, and a plurality of springs can be arranged, thereby improving durability. Is clear.

It is sectional drawing which shows embodiment of this invention about one block formation space. It is sectional drawing similar to FIG. 1 which shows other embodiment. It is a top view of the block shape | molded with the apparatus shown in FIG. It is a figure which shows a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vulcanization mold 2 Block formation space 3 Vent hole 4 Enlarged end 5 Valve body 6 Valve seat 7 Valve rod 8 Small hole 9 Stopper 10 Large diameter hole 11 Coil spring B Block CR Central area RU Streaked enclosure

Claims (2)

In a mold for vulcanizing a tire having a block pattern,
One or more vent holes are formed corresponding to the block forming position, and this vent hole and the block forming space are communicated with each other and blocked, and almost the entire grounding surface of the formed block is formed. The tire vulcanization mold degassing device is provided with at least one spring member for urging the valve body in a direction away from the valve seat.   The degassing device for a tire vulcanization mold according to claim 1, wherein the spring member is a coil spring, and the coil spring is disposed in an enlarged end portion of the vent hole on the block forming space side.

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