JPH0128686B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tire vulcanizer, particularly a tire equipped with a central mechanism that uses mechanical elevating means, such as converting rotational motion into linear motion, as means for expanding and contracting deformation of an elastic molded body for shaping. In the vulcanizer,
The present invention relates to a new control means that allows preshaping using the elastic molded body and thermopressure medium to be performed under optimal conditions.

An upper mold and a lower mold that can be opened and closed, a central mechanism placed in the center of the lower mold that can be raised and lowered, an elastic molded body called a bladder that can be expanded and contracted at both ends supported by the central mechanism, and supplied into the molded body. Tire vulcanizers are well known that shape and vulcanize green tires using a hot-pressure medium such as steam and heating means provided on both the upper and lower molds. Conventionally, in this type of tire vulcanizer, the central mechanism body has a fluid pressure cylinder structure to shape the inner surface shape of the green tire and to expand and contract an elastic molded body called a bladder, which acts as an internal pressure retaining member during hot-flow molding. The upper ring supports and fixes the lower end of the elastic molded body, and the upper ring that supports the upper end is connected to a piston rod that is raised and lowered by water or other fluid pressure in the fluid pressure cylinder, so that the upper ring can be raised and lowered. However, recently, in order to avoid the complication of the fluid pressure cylinder structure and the complication of the seal structure, for example, screw shafts and screw nuts have been used as means for raising and lowering the upper ring. It is also known to employ central mechanisms using mechanical lifting means, such as a rack and pinion, which convert rotational motion into vertical and linear motion. In addition, in the shaping process using the elastic body, the elastic molded body is deformed and charged into the green tire set on the open lower mold via a tire loader etc. by lowering the upper ring, and at the same time The preshaping process involves supplying a hot-pressure medium to the upper mold, and the upper mold is closed onto the lower mold, and when the upper mold is closed, the upper ring is lowered together, and as both molds are closed, the elastic molded body is completely adapted to the inner surface of the green tire. A two-stage process including the shaping process is required, and in the pre-shaping process, when charging the elastic molded body into the green tire, the green tire is prevented from being shifted from its center or tilted. Furthermore, it is necessary to prevent air from entering between the inner surface of the green tire and the outer surface of the elastic molded body. Conventionally, when performing this preshaping process, the lowering speed of the upper ring remains constant, regardless of whether the elastic molded body is raised and lowered by fluid pressure or by mechanical lifting means. Even when supplying the thermopressure medium to the inside, the supply remains at a constant pressure, which can cause problems such as off-centering or tilting of the green tire, or air intrusion. This is difficult to obtain, and this causes variations in the quality of vulcanized tires.

The present invention has solved these problems, and its features include an upper mold and a lower mold that can be opened and closed, and a means for expanding and contracting the elastic molded body for shaping, which is provided at the center of the lower mold. In a tire vulcanizer that shapes and vulcanizes a green tire through the elastic molded body and a thermopressure medium supplied into the molded body, a central mechanism equipped with a When carrying out preshaping, in which an elastic molded body is charged and attached to the inner surface of a green tire, the lowering speed of the upper ring that holds one end of the elastic molded body in the central mechanism is controlled by The pressure of the thermopressure medium and the inflow flow rate are adjusted in parallel throughout the entire stroke, and the upper and lower molds are equipped with opening/closing means.
The center mechanism is disposed at the center of the lower mold so as to be freely raised and lowered, and is equipped with a means for expanding and contracting the elastic molded body for shaping, and a means for supplying a thermopressure medium for shaping, and the raising and lowering means of the central mechanism is variable in speed. and the thermopressure medium supply means includes a control means for adjusting pressure and flow rate in the lifting means of the central mechanism in correspondence with speed change control in the prime mover.

The present invention will be described in detail below based on the illustrated embodiment.The drawing shows only the relevant parts of a tire vulcanizer as an embodiment of the present invention, but there is a lower part on the base 2 of the vulcanizer frame. The mold 4 is installed in a fixed manner, whereas the upper mold 3 is installed on a movable top link 1 that can be freely rotated or vertically raised and lowered, so that it can be opened and closed with respect to the lower mold 4. These are similar to known tire vulcanizers, and although not shown, both the upper and lower molds 3 and 4 are provided with a dome or the like around them. A lift cylinder 17, which occupies the central position of the lower die 4 and is the main body of the central mechanism, is inserted into and supported by a cylinder guide 14 fixed on the base 2 side via a packing 15 so as to be able to rise and fall freely. A knockout lever 18 as a cylinder elevating member is engaged with the lower end of a certain gear case 19, so that the cylinder 17 after vulcanization is raised. A lower ring 8 is integrally provided at the upper end of the lift cylinder 17, and the lower end of an elastic molded body 5, which is formed into a substantially cylindrical shape from rubber or other elastic material and is called a bladder, is supported by a clamp. The upper end of the molded body 5 is similarly clamped by an upper ring 7 provided at the upper end of a piston rod 9 which is inserted into the lower ring 8 through a V-packing 33 so as to be able to move up and down. The bush 11 is fitted into the lift cylinder 17 so as to be movable up and down. In order to move the piston rod 9 up and down, in the present invention, a screw nut (including a ball screw nut) 12 is attached to the lower end of the sliding bush 11 as shown in the drawing, and the screw nut 12 occupies the center position of the lift cylinder 17. The screw shaft (including the ball screw shaft) 13 is supported by a bearing on the gear case 19 side so as to be rotatable in forward and reverse directions, and the sliding bush 11 is unrotatably screwed into the lift cylinder 7.
By engaging an inlet pipe 16 and an outlet pipe 20 installed therein for supplying steam or other thermal pressure medium, the screw nut 12 moves up and down linearly through the forward and reverse rotation of the screw shaft 13. With this, the sliding button 11
The piston rod 9 rises and falls through the upper and lower pipes 16 and 20, and the elastic molded body 5 expands and contracts through the upper ring 7. It is configured so that it is. That is, in the present invention, when raising and lowering the piston rod 9, instead of supplying fluid pressure into the lift cylinder 17 to raise and lower the rod 9, the rotational movement of the screw nut 12 and the screw shaft 13 is converted into vertical and linear movement as described above. Mechanical elevating means such as conversion is used. In the present invention, in the above-mentioned central mechanism, a fixed-speed motor such as a DC servo motor, a stepping motor, or another rotary motor 21 whose speed can be freely controlled is used as the motor of the screw shaft 13, which is the driving shaft for the vertical movement. It is. This rotating prime mover 21
is a reversible type that can freely rotate in forward and reverse directions and is equipped with a brake device. As a mechanism for transmitting forward and reverse rotational power from the rotating prime mover 21 to the screw shaft 13, the prime mover 21 is attached to the outside of the gear case 19 as shown in the figure, and the output shaft 21a of the prime mover 21 is connected to the gear case 19.
It is connected via a joint 26 to the shaft 32a of a bevel gear 32 mounted on the screw shaft 13, and the bevel gear 32 is meshed with a bevel gear 31 provided on the screw shaft 13, but of course, this transmission mechanism can be other than the example shown.

Furthermore, in the present invention, the inlet pipe 16 is connected to the port 16a at the lower end of the inlet pipe 20 of the outlet pipe 20 provided in the lift cylinder 17 in order to supply the thermopressure medium into the elastic molded body 5. On the thermopressure medium supply pipe line 34 side,
Both a pressure control valve 24 for arbitrarily adjusting the pressure of the thermopressure medium supplied into the elastic molded body 5 and a flow rate control valve 23 for adjusting the inflow flow rate are provided. That is, the variable speed prime mover 2 that can freely control the speed change described above.
1, the piston rod 9 is lowered through the rotation of the screw shaft 13 and the screw nut 12 screwed thereto moves straight, and the elastic molded body 5 is placed on the lower mold 4 by the loader paddle 10 of the tire loader. When loading the green tire 6 along the inner surface of the green tire 6 that has been carried in and set, the lowering speed of the piston rod 9 that deforms the elastic molded body 5 and the upper ring 7 that is integrated with the piston rod 9 is controlled by a screwdriver over the entire length of the lowering stroke. By converting the rotational speed of the shaft 13, it is possible to freely change the rotational speed and control the lowering speed to an optimum speed that prevents the green tire 6 from shifting its center or tilting. In supplying a thermopressure medium such as steam into the elastic molded body 5 through the let pipe 16 to promote deformation and tension of the molded body 5,
Through adjustment by the flow rate control valve 22 and pressure control valve 24 provided in the supply pipe line 34, the supply pressure of the thermopressure medium is adjusted so that air does not get mixed between the outer surface of the elastic molded body 5 and the inner surface of the green tire 6. The inflow flow rate is controlled to an optimum state.

In addition, in the above embodiments, the present invention is explained using the central mechanism of the mechanical elastic molded body lifting means.
It is possible to use means for lifting and lowering the elastic molded body using fluid pressure such as water pressure or oil pressure, and the effect in this case is the same.

Shaping and hot-flow forming of the green tire 6 according to the present invention are performed as follows. In the first preshaping process in which the elastic molded body 5 is internally loaded onto the green tire 6 that has been carried and set on the open lower mold 4, the piston rod 9 and the upper ring 7 are placed at a higher position than shown in the figure. The elastic molded body 5 is in an upright cylindrical shape extending between the upper and lower rings 7 and 8, and in this state, the green tire 6
is loaded and set onto the lower die 4 as shown in the figure through being held by the loader paddle 10, and then by driving the variable speed prime mover 21 in forward rotation with the brake released, the screw is loaded through the interlocking of the bevel gears 32 and 31. The shaft 13 rotates in the normal direction, and the pipes 16, 20 of the sliding bush 11 of the screw nut 12
The upper ring 7 of the piston rod 9 descends along with the piston rod 9 through straight movement due to engagement and restraint.
The elastic molded body 5 is deformed into a contracting and closing shape using the lower end fixed part by the lower ring 8 as a fulcrum, and is inserted along the inner surface of the green tire 6 as shown in the figure. By supplying the pressure medium, the deformation of the molded body 5 is promoted from the inner surface side by the internal pressure of the supplied thermopressure medium, and the molded body 5 is brought into tight pressure contact with the inner surface of the tire 6 in a tensioned state. Creeping loading of the molded body 5 onto the inner surface of the tire is obtained. At this time, a rotary detector 23 as shown in the variable speed prime mover 21 counts the number of rotations, and when the lower limit of the set value is reached, a stop signal is issued to the prime mover 21 to stop the prime mover 21 and at the same time. By activating the brake device, the preshaping process is completed with the elastic molded body 5 being completely loaded and pressed into contact with the inner surface of the green tire 6. Next, the shaping process is started by closing the upper mold, that is, with the start of the top link 1, the upper mold 3 enters the closing operation toward the lower mold 4, and in the middle of its descent, the upper mold 3 moves into the upper ring 7.
I will come across this. This collision position is preset as a set value in a separate counter, and when the upper die 3 comes to the collision position with the upper ring 7, the brake device on the variable speed prime mover 21 side is released via the counter. By releasing the brake device by issuing a signal, the screw shaft 13 can freely rotate when the upper mold 3 collides with the upper ring 7, engages with it, and descends together with it. As a result, the upper ring 7 is carried along with the upper mold 3 as the screw nut 12 and the piston rod 9 move straight down, and the lowering movement of the upper mold 3 stops when the upper mold 3 closes with respect to the lower mold 4. The brake device in the variable speed prime mover 21 is returned to the starting position again. After the upper and lower molds 3 and 4 are closed and the molds are clamped, as is known, although not shown, the upper and lower molds 3 and 4 are heated by a hot platen, and the internal pressure of the thermopressure medium in the elastic molded body 5 is increased. Further, the green tire 6 is vulcanized and molded in a predetermined manner by supplying a thermopressure medium into the dome. Once vulcanization is completed,
As is also known, as the upper mold 3 rises and retracts and the cylinder lift 17 rises via the knockout lever 18, the tire 6 rises and retracts from the lower mold 4 side together with the elastic molded body 5, and then the variable speed By driving the prime mover 21 in the reverse direction, the upper ring 7 accompanies the piston rod 9 through the upward movement of the screw nut 12 due to the reverse rotation of the screw shaft 13, so that the elastic molded body 5 is pulled out from the inner surface of the vulcanized tire 6. Since it extends into an upright cylindrical shape, as the lift cylinder 17 rises, the vulcanized tire 6 is supported by a tire unloader or the like.
is carried out of the vulcanizer by bypassing the stretched elastic molded body 5, and the piston rod 9
When the upper ring 7 reaches its highest position, the prime mover 2
1 will be stopped when the counter upper limit value in the detector 23 is reached.

In the above-mentioned series of tire shaping and vulcanization molding processes, the present invention particularly applies to the pre-shaping process in which the elastic molded body 5 is charged into the inner surface of the green tire 6 while supplying a thermopressure medium. The lowering speed of the upper ring 7 for supporting and charging deformation is changed throughout the lowering stroke by changing the rotational speed on the variable speed prime mover 21 side, and at the same time the upper ring 7 is supplied into the elastic molded body 5. By freely adjusting the pressure of the hot-pressure medium and the inflow flow rate while supplying it, the center shift or inclination of the green tire 6, as well as air intrusion between the inner surface of the tire and the outer surface of the molded body, etc. do not occur. This method has a great feature and advantage in that an optimal preshaping state can be obtained.
As before, the upper ring 7 is lowered onto the inner surface of the green tire 6 set on the lower mold 4 at a preset mechanical constant lowering speed, and the same preset constant pressure is applied. However, if only a fixed amount of thermopressure medium is mechanically supplied, the set of green tires 6 itself cannot be firmly fixed and held, and furthermore, due to the difference in the shape and size of the green tires, the tire The center of the upper ring is likely to shift or tilt, and the outer inner pressure of the elastic molded body cannot be adhered to the inner surface of the tire evenly, and air is likely to remain mixed in between the joint surfaces of the two. By freely changing the descending speed of No. 7 over the entire length of the descending stroke, and correspondingly changing the supply pressure and inflow flow velocity of the thermopressure medium, it can quickly respond to the inner surface shape and size of the target tire. This is achieved by always accurately controlling the optimal preshaping, which allows us to expect accurate, stable and homogeneous vulcanization molding results, and to provide product tires with consistent quality. . Moreover, according to the present invention, there is no need to significantly change the content of the conventional vulcanization molding operation, and it is sufficient to change the descending speed, change the content of thermopressure medium supply, and control them, which causes particular difficulty and trouble in implementation. This is an excellent improvement over the conventional uniform, mechanical preshaping process.

[Brief explanation of drawings]

The drawings are longitudinal sectional front views of essential parts of an embodiment of the method and apparatus of the present invention. 3... Upper die, 4... Lower die, 5... Elastic molded body, 6... Green tire, 7... Upper ring, 8... Lower ring, 9... Piston rod, 12... Screw nut, 13... Screw shaft, 16... Inlet pipe, 17...lift cylinder, 21...variable speed prime mover, 22...flow control valve, 24...pressure control valve.

Claims (1)

[Scope of Claims] 1. The elastic molded body and the shaping are provided by an upper mold and a lower mold that can be opened and closed, and a central mechanism provided at the center of the lower mold and equipped with means for expanding and contracting the elastic molded body for shaping. In a tire vulcanizer that shapes and vulcanizes a green tire through a thermopressure medium supplied into the body, an elastic molded body is charged onto the inner surface of the green tire set on the lower mold while supplying a thermopressure medium. When preshaping is carried out, the descending speed of the upper ring that holds one end of the elastic molded body in the central mechanism is successively changed over the entire descending stroke, and the pressure and inflow flow rate of the thermopressure medium are A method for controlling preshaping of a central mechanism in a tire vulcanizer, characterized in that adjustments are made in parallel. 2. An upper mold and a lower mold equipped with an opening/closing means, a central mechanism disposed in the center of the lower mold so as to be freely raised and lowered, and equipped with means for expanding and contracting deformation of the elastic molded body for shaping, and equipped with a means for supplying a thermopressure medium for shaping. It is characterized in that the elevating means of the central mechanism is variable in speed, and the thermopressure medium supply means includes a control means for adjusting pressure and flow rate in response to speed change control in the elevating means of the central mechanism. A control device for preshaping of the central mechanism in a tire vulcanizer.