JP2020146968A - Demolding jig and demolding method - Google Patents

Abstract

To provide a demolding jig and a demolding method capable of easily demolding a rubber roller having slanted knurled ribs from a transfer molding mold.SOLUTION: A demolding jig is formed of a cylindrical outer cylinder with one side open and a rod-like rotary shaft inserted inside of the outer cylinder. An inner circumferential surface of the outer cylinder is formed of recessed grooves corresponding to a slanted knurled grooves. An outer circumferential surface of the rotary shaft is embedded of a plurality of roller balls fittable to the recessed grooves such as to expose apexes. By pressing the tip of the outer cylinder against one end surface of a rubber product in the molding cavity and pushing the rotary shaft along the inner circumferential surface of the outer cylinder, the roller balls are fitted into the recessed grooves of the outer cylinder. The roller balls advances in the recessed grooves to rotate the outer cylinder along the slanted knurled grooves, and demolds the rubber product from the one end surface toward the other end surface.SELECTED DRAWING: Figure 3

Description

The present invention relates to a demolding jig and a demolding method for removing a cylindrical rubber product having ribs oblique to its surface from a mold.

In an image forming apparatus such as a printer or a facsimile, a cylindrical rubber roller having ribs oblique to the surface is used for good paper feeding (see Patent Document 1). FIG. 13A is a side view of the rubber roller 1 for general paper feeding, and FIG. 13B is a front view thereof. Further, FIG. 14 is a cross-sectional view of the vicinity of the outer peripheral surface of the rubber roller 1 cut in a direction orthogonal to the axial direction of the rubber roller 1.

The shaft 8 of the rubber roller 1 is inserted into the hole 1a at the center. The shaft 8 is driven by a drive unit such as a motor (not shown) to rotate the rubber roller 1. Such a rubber roller is usually manufactured by transfer molding using a transfer molding die as shown in FIGS. 15A and 15B.

The transfer molding die is usually configured such that the cavity mold 62, the pot mold 63, and the piston mold 64 are sequentially placed on the lower mold 61 as shown in FIG. 15 (a), and as shown in FIG. 15 (b). Will be done. Then, by pushing the rubber material put into the pot portion 67 of the pot mold 63 by the piston mold 64, the rubber material is pushed into the molding cavity C provided in the cavity mold 62 from the gate portion 66 below the pot mold 63. A rubber product is formed by injecting into a rubber product, pressurizing and heating for a predetermined time. The center pin 70 is provided to form a hole in the center of the rubber roller through which the shaft is inserted, and the guide pin 65 is provided for adjusting the position.

When the molding is completed, only the piston mold 64 is separated first, and then the lower mold 61 and the pot mold 63 are separated in this order, and the rubber product is taken out from the cavity mold 62. By separating the transfer molding dies in this order, the rubber product molded in the molding cavity C is pulled upward from the molding cavity C of the cavity mold 62 together with the rubber in the gate portion 66 of the pot mold 63 and demolded. Will be done.

On the other hand, in recent years, in order to improve paper feed, diagonal knurled ribs 3 having a predetermined width in the circumferential direction of the outer peripheral surface 1b of the rubber roller have been used as the rubber roller 1, and a plurality of such rubber rollers have been used. The diagonal knurled ribs 3 of the book extend obliquely with respect to the axis X of the rubber roller 1 at equal intervals. As schematically shown in FIG. 16, such a rubber roller 1 is formed by using a transfer molding die having a cavity mold 5 in which an oblique knurled groove is provided on the cavity surface 5a (oblique knurling). (See Patent Document 2).

Japanese Unexamined Patent Publication No. 2016-30418 JP-A-2018-43851

However, in the case of the rubber roller 1 having the vulcanized diagonal knurled rib 3, it is not possible to remove the rubber product by pulling it upward from the cavity-type molding cavity together with the rubber in the pot-type gate portion as in the conventional case. It was not easy, and there was a problem that the rubber roller 1 remained in the molding cavity due to the gate rubber being cut. Further, the rubber roller 1 that has been removed from the mold may also have a problem such as a part of the diagonal knurled rib 3 being chipped, resulting in a decrease in productivity.

These defects are more likely to occur when the angle of the oblique knurled groove of the cavity surface 5a is larger than that in the vertical direction, which is the drawing direction.

Therefore, an object of the present invention is to provide a demolding jig and a demolding method capable of easily demolding a rubber roller having diagonal knurled ribs from a transfer molding die.

The present inventor has diligently studied the solution to the above problem, found that the above problem can be solved by the invention described below, and has completed the present invention.

The invention according to claim 1
A demolding jig used to demold a cylindrical rubber product molded using a transfer molding die provided with diagonal knurled grooves on the cavity surface from the molding cavity of the transfer molding die. There,
It is formed of a cylindrical outer cylinder with one opening and a rod-shaped rotating shaft inserted inside the outer cylinder.
A concave groove corresponding to the diagonal knurled groove is formed on the inner peripheral surface of the outer cylinder.
A plurality of roller balls that can be fitted into the concave groove are embedded in the outer peripheral surface of the rotating shaft so as to expose the crown.
The tip of the outer cylinder is pressed against one end surface of the rubber product in the molding cavity, and the rotating shaft is pushed along the inner peripheral surface of the outer cylinder to fill the concave groove of the outer cylinder. The rubber product is demolded from one end face to the other end face while the roller ball is fitted and the roller ball advances the concave groove to rotate the outer cylinder along the diagonal lorlet groove. It is a demolding jig characterized by being configured to do so.

The invention according to claim 2
The demolding jig according to claim 1, wherein a truncated cone-shaped protrusion is provided at the tip of the outer cylinder.

The invention according to claim 3
Around the protrusion, a width of 1/4 or more from the inside to the outside in the radial direction of one end face of the rubber product, leaving within twice the depth of the diagonal knurled groove from the outside, said. The demolding jig according to claim 2, wherein a horizontal surface is formed so as to be in contact with one end surface of the rubber product.

The invention according to claim 4
The demolding jig according to any one of claims 1 to 3, wherein a non-slip processing is applied to a portion of the outer cylinder that comes into contact with the rubber product.

The invention according to claim 5
The demolding jig according to claim 4, wherein the non-slip processing is a rib processing or a roughening processing.

The invention according to claim 6
The demolding jig according to any one of claims 1 to 5, wherein a plurality of demolding jigs are arranged.

The invention according to claim 7
Claims 1 to 6 are characterized in that a ring-shaped first stopper is provided on the inner peripheral surface of the outer cylinder, and a ring-shaped second stopper is provided on the outer peripheral surface of the rotating shaft. The demolding jig according to any one of the above items.

The invention according to claim 8 is
The material of the rubber product is one or more selected from NR, IR, BR, SBR, IIR, NBR, EPDM, CR, ACM, CSM, U, Q, FKM, EVA, CO, T. The demolding jig according to any one of claims 1 to 7, wherein the component is a durometer type A hardness specified in JIS K 6253 and the hardness is 30 to 90 degrees.

The invention according to claim 9
This is a demolding method for demolding a cylindrical rubber product formed by using a transfer molding die provided with an oblique knurled groove on the cavity surface from the transfer molding die.
Using the demolding jig according to any one of claims 1 to 8,
The rotating shaft is inserted into the inner peripheral surface of the outer cylinder, a roller ball is fitted into the concave groove of the outer cylinder, and the tip end portion of the outer cylinder is pressed against one end surface of the rubber product.
The outer cylinder is rotated along the diagonal knurled groove by advancing the roller ball along the concave groove while pushing the rotating shaft into the outer cylinder.
Demolding characterized by pushing up the formed rubber product in the molding cavity from one end face toward the other end face while rotating the rubber product by the rotation of the outer cylinder. The method.

According to the present invention, it is possible to provide a demolding jig and a demolding method capable of easily demolding a rubber roller having diagonal knurled ribs from a transfer molding die.

It is a partial cross-sectional view explaining the molding method of a rubber roller by a transfer molding die. (A) is a plan view for explaining one embodiment of the demolding jig and the demolding method according to the present invention, and (b) is a partial front sectional view. It is a figure explaining the method of demolding using the demolding jig of this invention in more detail. It is a schematic perspective view which shows the tip part of the outer cylinder of the demolding jig of this invention. It is a schematic cross-sectional view for demonstrating the roller ball of the demolding jig of this invention. It is a schematic plan view for demonstrating the roller ball of the demolding jig of this invention. It is a schematic cross-sectional view for demonstrating the shaft of the demolding jig of this invention. 5 is a schematic perspective view showing the positional relationship between the roller ball and the shaft shown in FIGS. 5 to 7. It is a schematic cross-sectional view for demonstrating the modification of the embedding of a roller ball. It is a schematic plan view for demonstrating the modification of the embedding of a roller ball. It is a schematic cross-sectional view for demonstrating the shaft of the demolding jig of this invention. It is a schematic cross-sectional view for demonstrating the modification of the demolding jig. (A) is a side view of a rubber roller for general paper feeding, and (b) is a front view thereof. It is sectional drawing of the vicinity of the outer peripheral surface of a rubber roller cut in the direction orthogonal to the axial direction of a rubber roller. (A) is a schematic exploded view of a transfer molding die, and (b) is a schematic side view of a transfer molding die. It is a partial cross-sectional view which shows the molding of the rubber roller by the transfer molding die provided with the knurled groove.

Hereinafter, the present invention will be described based on the embodiments.

1. 1. Features of the present invention The present invention is characterized in that a rubber roller having diagonal knurled ribs is demolded from a transfer molding die by pushing it forward while rotating it from one side to the other with a rotatable demolding jig. There is.

2. 2. Basic Configuration of Demolding Jig FIG. 1 is a partial cross-sectional view illustrating a method of molding a rubber roller by a transfer molding die. FIG. 2A is a plan view for explaining an embodiment of the demolding jig according to the present invention, and FIG. 2B is a partial front sectional view.

The demolding jig 10 is a cylindrical rubber roller 1 formed by using a transfer molding die in which an oblique knurled groove (not shown) is provided on the cavity surface 5a of the cavity mold 5. It is used when removing from the cavity mold 5.

The demolding jig 10 has a cylindrical outer cylinder 12 having an opening at the bottom, a rod-shaped rotating shaft 14 inserted inside the outer cylinder 12, and a rotating shaft 14 fixed to the lower end surface of the rotating shaft 14. It is provided with a large-diameter disk portion 16 arranged at a central position.

The outer diameter of the outer cylinder 12 is slightly smaller than the inner diameter of the cavity type 5, and the inner diameter of the outer cylinder 12 is slightly larger than the outer diameter of the rotating shaft 14. A concave groove 22 corresponding to the oblique knurled groove of the cavity surface 5a is formed on the inner peripheral surface 12a of the outer cylinder 12.

A plurality of roller balls 36 that can be fitted in the concave groove 22 are embedded in the outer peripheral surface of the rotating shaft 14 so as to expose the crown. As a result, the rotating shaft 14 is configured to be able to move forward and backward in the axial direction while rotating along the concave groove 22 of the outer cylinder 12.

By pressing such a demolding jig against one end of a rubber roller having diagonal knurled ribs, inserting the rotating shaft 14 inside the outer cylinder 12 and pushing it forward, the demolding is performed from the transfer molding die while rotating the rubber roller. can do.

3. 3. Specific Configuration of Demolding Jig FIG. 3 is a diagram illustrating in more detail a method of demolding using the demolding jig 10 of the present invention.

As shown in FIG. 3, the outer cylinder 12 has a cylindrical shape with an opening at the bottom as described above, and the inner peripheral surface 12a of the outer cylinder 12 has an oblique knurl provided on the cavity surface 5a of the cavity type 5. The concave groove 22 corresponding to the groove is formed diagonally. The diagonal groove 22 has the same inclination angle as the oblique knurled groove provided on the cavity surface 5a of the cavity type 5, and is provided in the opposite direction. The cross section of the concave groove 22 is formed in a semicircular shape corresponding to the spherical surface of the roller ball 36.

A truncated cone-shaped protrusion 24 having an outer diameter corresponding to the inner diameter of the rubber roller 1 is formed on the tip portion 12b of the outer cylinder 12 in contact with the lower end surface of the rubber roller 1. As a result, the outer cylinder 12 can be easily inserted into the hole of the rubber roller 1, and the rubber roller 1 can be firmly supported from the inside to perform reliable demolding.

A horizontal plane 28 is formed in a ring shape around the protrusion 24. The horizontal plane 28 has a width of 1/4 or more from the inside to the outside in the radial direction of the lower end surface of the annular shape of the rubber roller 1, leaving within twice the depth of the diagonal knurled groove of the cavity surface 5a from the outside. , It is formed so as to be in contact with the lower end surface of the rubber roller 1.

By setting the width to "1/4 or more", the rubber roller 1 bulges outward when the tip portion 12b of the outer cylinder 12 enters the hole of the rubber roller 1, and the rubber roller 1 rotates in the molding cavity of the cavity type 5. It is possible to reduce the occurrence of a problem that the problem cannot be achieved. As a result, the horizontal surface 28 can hold the rubber roller 1 so that the rotating rubber roller 1 is not damaged. Further, by setting the horizontal plane 28 to "within twice the depth of the diagonal knurled groove", a clearance of, for example, about 1 mm is formed between the outer cylinder 12 and the convex portion in the molding cavity of the cavity type 5. Therefore, it is possible to reduce the occurrence of interference between the two.

As shown in FIG. 4, ribs 26 extending radially from the inside to the outside are formed on the inclined surface 25 of the projecting portion 24 and the horizontal surface 28 in contact with the lower end surface side of the rubber roller 1. Has been done. The non-slip processing makes it possible to hold the rubber roller 1 even more reliably. As a non-slip process, roughening process by blasting is also possible.

Next, the roller ball 36 constituting the demolding jig of the present embodiment will be described. However, since the roller ball plays an important role in the present invention and has been devised in various ways in the present embodiment. The roller ball 36 will be described in detail below.

A plurality of roller balls 36 that can be fitted into the concave groove 22 of the outer cylinder 12 are embedded in the outer peripheral surface 14a of the rotating shaft 14 so as to expose the crown. The roller balls 36 are arranged diagonally on the outer peripheral surface 14a of the rotating shaft 14 so as to correspond to the position of the concave groove 22 diagonally formed on the inner peripheral surface 12a of the outer cylinder 12. ..

Therefore, when the tip portion 12b of the outer cylinder 12 is pressed against the lower end surface of the rubber roller 1 and the rotating shaft 14 is pushed along the inner peripheral surface 12a of the outer cylinder 12, the roller ball 36 is placed in the concave groove 22 of the outer cylinder 12. Can be fitted. Then, as the roller ball 36 advances in the concave groove 22, the rotating shaft 14 is configured to move from the bottom to the top while rotating along the oblique groove 22. There is.

As shown in FIGS. 5 to 8, about two-thirds of the roller ball 36 is embedded in the roller ball recess 42 formed on the outer peripheral surface 14a of the rotating shaft 14. The roller ball recess 42 has a substantially U-shaped cross section and a combination of a circular shape and an equilateral triangle in a plan view. The roller ball recess 42 is formed between a digging portion 42a having a combination of a circular shape and an equilateral triangle in a plan view on the opening side and a dish-shaped portion 42b having a circular flat view on the bottom side. It has a stepped portion 42c. 5 is a schematic cross-sectional view for explaining the roller ball of the demolding jig of the present invention, FIG. 6 is a schematic plan view for explaining the roller ball, and FIG. 7 is for explaining the shaft. It is a schematic cross-sectional view for this.

On the stepped portion 42c, three shafts 40 are arranged horizontally with both ends supported by the stepped portion 42c. A gap S is formed on the lower side of the shaft 40. Each of the three shafts 40 is arranged at the center of the three sides of an equilateral triangle in a plan view. The roller ball 36 is supported at three points on the three shafts 40 and is rotatable in the roller ball recess 42.

A ring-shaped roller ball lid 38 having an inverted triangular cross section is placed on a part of the circular outer peripheral portion of the opening of the roller ball recess 42 so that the roller ball 36 does not come out from the roller ball recess 42. It is covered from.

Further, FIGS. 9 to 11 show a modified example of embedding the roller ball 36. In the case of this modified example as well, about two-thirds of the roller ball 36 is embedded in the roller ball recess 43 formed on the outer peripheral surface 14a of the rotating shaft 14 as in the above example. The roller ball recess 43 has a substantially U-shape in cross section, but unlike the above-mentioned example, it has an equilateral triangle in plan view. Further, the recess 43 for the roller ball is also formed between the digging portion 43a having an equilateral triangular view on the opening side and the dish-shaped portion 43b having a circular view on the bottom side, unlike the above-mentioned example. It has a stepped portion 43c. 9 is a schematic cross-sectional view for explaining a modified example of embedding a roller ball, FIG. 10 is a schematic plan view for explaining a modified example of embedding a roller ball, and FIG. 11 is a schematic plan view. It is a schematic cross-sectional view for demonstrating the shaft of the demolding jig of this invention.

On the stepped portion 43c, three shafts 40 are arranged horizontally with both ends supported by the stepped portion 43c. A gap S is formed on the lower side of the shaft 40. Each of the three shafts 40 is arranged at the center of the three sides of an equilateral triangle in a plan view. The roller ball 36 is supported at three points on the three shafts 40 and is rotatable in the roller ball recess 43.

Further, a ring sheet-shaped roller ball lid is provided on a part of the outer peripheral portion of the triangle of the opening of the roller ball recess 43 so that the roller ball 36 does not come out from the roller ball recess 43 as in the above example. 39 is covered from above.

Further, as shown in FIG. 12, the demolding jig 10 may include a ring-shaped first stopper 50 and a ring-shaped second stopper 52. Note that, in FIG. 12, the roller ball 36 provided on the outer peripheral surface 14a of the rotating shaft 14 is not shown for simplification. The first stopper 50 is fitted and arranged in the vicinity of the opening of the inner peripheral surface 12a of the outer cylinder 12. The second stopper 52 is fitted and arranged near the tip of the outer peripheral surface 14a of the rotating shaft 14. Specifically, after the rotating shaft 14 is inserted through the opening of the outer cylinder 12, the first stopper 50 is fitted to the inner peripheral surface 12a of the outer cylinder 12. As a result, a structure is obtained in which the rotating shaft 14 does not come off from the outer cylinder 12.

Further, although only one jig 10 may be used for removing the mold, it is more preferable that a plurality of jigs 10 are provided side by side. When there are a plurality of mold removing jigs, since the plurality of rubber rollers 1 can be removed at the same time, it is possible to suppress a decrease in the mold temperature, and in continuous molding, the time for heating the mold and the vulcanization time are shortened. As a result, work efficiency can be improved.

4. Demolding method Next, the demolding method will be described with reference to FIGS. 1 to 3.

As shown in FIG. 1, the rubber roller 1 is formed by using a transfer molding die provided with a cavity mold 5 which has been subjected to a process of providing an oblique knurled groove on the cavity surface 5a (oblique knurling process).

As schematically shown in FIG. 3, first, the demolding jig 10 is inserted into the outer cylinder 12 so that the rotating shaft 14 is in sliding contact with the inner peripheral surface 12a of the outer cylinder 12. That is, the roller ball 36 of the rotating shaft 14 is fitted into the concave groove 22 formed on the inner peripheral surface 12a of the outer cylinder 12.

Next, as schematically shown in FIGS. 2A and 2B, from below the molding cavity of the transfer molding die separated in the open state, the outer cylinder 12 of the demolding jig 10 The protruding portion 24 of the tip portion 12b is inserted into the hole of the rubber roller 1, and the horizontal surface 28 is pressed against the lower end surface of the rubber roller 1. When the rotating shaft 14 of the demolding jig 10 is rotated in the counterclockwise direction, the roller ball 36 advances along the concave groove 22, and the tip of the rotating shaft 14 hits the ceiling surface of the outer cylinder 12. Is pushed into the outer cylinder 12 until.

Further, as the rotation shaft 14 is rotated in the counterclockwise direction, the outer cylinder 12 is rotated upward along the diagonal knurled groove of the cavity surface 5a of the cavity type 5 in the counterclockwise direction. Advance. Due to the forward rotation of the outer cylinder 12 in the counterclockwise direction, the rubber roller 1 formed in the molding cavity of the cavity type 5 also rotates in the counterclockwise direction from the lower end surface to the upper end surface of the cavity type 5. Is pushed up.

The mold removal jig 10 is removed from the cavity mold 5 before the rubber roller 1 is completely removed from the cavity mold 5. After that, the rubber roller 1 is manually recovered from the cavity mold 5 and completely removed from the mold.

In the demolding method, the rubber roller 1 is demolded by pushing it up from the lower end surface of the cavity mold 5 toward the upper end surface, but conversely, the rubber roller 1 is directed from the upper end surface to the lower end surface of the cavity mold 5. It may be a method of demolding by pushing down.

With the above configuration and method, the rubber roller 1 having the oblique knurled ribs 3 corresponding to the oblique knurled grooves of the cavity mold 5 can be easily demolded without generating rubber residue in the molding cavity. Further, even if the angle of the diagonal knurled groove of the cavity mold 5 is large, the mold can be smoothly removed and the rubber residue is unlikely to deteriorate. In particular, even a rubber roller having an angle of an oblique knurled rib of 30 ° to 50 °, which has been difficult in the past, can be smoothly demolded.

The material of the rubber roller 1 used in the present invention is NR (natural rubber), IR (isoprene rubber), BR (butadiene rubber), SBR (styrene butadiene rubber), IIR (butyl rubber), NBR (nitrile rubber), EPDM. (Ethethylene propylene rubber), CR (chloroprene rubber), ACM (acrylic rubber), CSM (chlorthrophonized polyethylene), U (urethane rubber), Q (silicone rubber), FKM (fluorine rubber), EVA (ethylene vinyl acetate) ), CO (Ebichlorohydrin rubber), T (polysulfide rubber) selected from one or more types of rubber as a rubber component, and a durometer type A hardness specified in JIS K 6253, which is 30 to 90 degrees. The product is preferred. By using these rubber rollers, the demolding jig of the present invention can efficiently demold the rubber rollers without generating rubber residue in the molding cavity.

1. 1. Experimental Example In the experimental example, a cylindrical rubber roller for a printer having diagonal knurled ribs formed on the surface was molded using a transfer molding die, and then removed using the mold removing jig 10 according to the present invention. Molded.

The number of diagonal knurled ribs on the rubber roller is 40, the width is 1 mm, and the height is 0.5 mm. As the material of the rubber roller, a compounded rubber in which 0.5 part of the curing agent TC-8 was added to 100 parts of the silicone rubber TSE221-4U manufactured by Momentive Materials was used. The rubber hardness is the durometer type A hardness specified in JIS K 6253, and is 40 degrees.

As the transfer molding die, a conventional transfer molding die for rubber roller molding composed of a lower mold, a cavity mold, a pot mold, and a piston mold was used. In the cavity type, the outer diameter of the molding cavity is φ20 mm, the inner diameter is φ13 mm, and the total length is 60 mm. The number of molding cavities is 16. In each experimental example, a cavity type of knurled groove having an angle shown in Table 1 was used.

The diameter of the pot-shaped gate portion is φ2.5 mm, and the gate portion is not tilted. The number of gates is four. The taper of the gate portion is 8 °. Molding was carried out at 170 ° C. for 10 minutes. After that, the transfer molding die was separated, and a mold removal jig was used for the cavity mold having the rubber molded product.

As for the demolding jig, 16 pieces were arranged side by side according to the position of the molding cavity so that 16 rubber rollers could be demolded at one time. Each of the demolding jigs has an outer cylinder having an inner diameter of 80 mm. The outer diameter of the rotating shaft is φ10 mm, and the total length thereof is 80 mm. The truncated cone-shaped protrusion formed at the tip of the outer cylinder has a trapezoidal cross-sectional view, an upper side of 11 mm, a lower side of 13 mm, and a height of 5 mm. The ribs as non-slip are rectangular in cross section of 1 mm square, and eight ribs are evenly formed on the inclined surface and the horizontal plane of the protruding portion.

The outer diameter of the roller ball embedded in the outer peripheral surface of the rotating shaft of the demolding jig is φ5 mm. The depth of the dug portion of the roller ball recess is 2 mm, and the depth of the dish-shaped portion is 1 mm. The shaft has a circular shape with a cross section of φ1 mm and a length of 3 mm.

2. 2. Evaluation Method After molding the experimental example under the conditions shown in Table 1, the state of the rubber residue in the molding cavity and the diagonal knurled ribs of the demolded rubber roller was visually confirmed and evaluated.

3. 3. Evaluation Results Table 2 shows the evaluation results of the experimental examples.

As a result of the experiment, the following was confirmed. In Experimental Examples 3 to 6 provided with the protrusions and the non-slip, the rubber rollers could be appropriately removed from all the molding cavities. In particular, even those having diagonal knurled grooves at angles of 40 ° and 50 ° (Experimental Example 4 and Experimental Example 5) could be appropriately demolded.

On the other hand, in the case of Experimental Example 1 having no protruding portion, the holding force on the inner peripheral surface of the rubber roller was weak, so that the rotation of the rubber roller along the cavity-type diagonal knurled groove was not sufficient. Therefore, the rubber roller was partially damaged.

In the case of Experimental Example 2 in which the protrusion was provided but the anti-slip was not provided, the holding force on the inner peripheral surface and the lower end surface of the rubber roller was weak, so that the rotation along the diagonal knurled groove was not sufficient. As a result, the rubber roller was slightly damaged.

From the above, it was confirmed that appropriate demolding can be performed by using a demolding jig provided with a non-slip protruding portion.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments. Various modifications can be made to the above embodiments within the same and equivalent range as the present invention.

1 Rubber roller 1a Central hole 1b Outer peripheral surface of rubber roller 3 Diagonal knurled rib 5, 62 Cavity type 5a Cavity surface 8 Shaft 10 Demolding jig 12 Outer cylinder 12a Inner peripheral surface of outer cylinder 12b Tip of outer cylinder 14 rotation Shaft 14a Outer surface of rotating shaft 16 Disc 22 Concave groove 24 Protruding part 25 Inclined surface 26 Rib 28 Horizontal plane 36 Roller ball 38, 39 Roller ball lid 40 Shaft 42, 43 Recessed part for roller ball 42a, 43a Digging part 42b, 43b Dish-shaped part 42c, 43c Step part 50 First stopper 52 Second stopper 61 Lower type 63 Pot type 64 Piston type 65 Guide pin 66 Gate part 67 Pot part 70 Center pin C Molding cavity S Gap X Rubber roller shaft

Claims (9)

A demolding jig used to demold a cylindrical rubber product molded using a transfer molding die provided with diagonal knurled grooves on the cavity surface from the molding cavity of the transfer molding die. There,
It is formed of a cylindrical outer cylinder with one opening and a rod-shaped rotating shaft inserted inside the outer cylinder.
A concave groove corresponding to the diagonal knurled groove is formed on the inner peripheral surface of the outer cylinder.
A plurality of roller balls that can be fitted into the concave groove are embedded in the outer peripheral surface of the rotating shaft so as to expose the crown.
The tip of the outer cylinder is pressed against one end surface of the rubber product in the molding cavity, and the rotating shaft is pushed along the inner peripheral surface of the outer cylinder to fill the concave groove of the outer cylinder. The rubber product is demolded from one end face to the other end face while the roller ball is fitted and the roller ball advances the concave groove to rotate the outer cylinder along the diagonal lorlet groove. A demolding jig characterized by being configured to do so. The jig for demolding according to claim 1, wherein a truncated cone-shaped protrusion is provided at the tip of the outer cylinder. Around the protrusion, a width of 1/4 or more from the inside to the outside in the radial direction of one end face of the rubber product, leaving within twice the depth of the diagonal knurled groove from the outside, said. The demolding jig according to claim 2, wherein a horizontal surface is formed so as to be in contact with one end surface of the rubber product. The demolding jig according to any one of claims 1 to 3, wherein the outer cylinder that comes into contact with the rubber product is subjected to anti-slip processing. The jig for demolding according to claim 4, wherein the non-slip processing is rib processing or roughening processing. The demolding jig according to any one of claims 1 to 5, wherein a plurality of demolding jigs are arranged. Claims 1 to 6 are characterized in that a ring-shaped first stopper is provided on the inner peripheral surface of the outer cylinder, and a ring-shaped second stopper is provided on the outer peripheral surface of the rotating shaft. The demolding jig according to any one of the above items. The material of the rubber product is one or more selected from NR, IR, BR, SBR, IIR, NBR, EPDM, CR, ACM, CSM, U, Q, FKM, EVA, CO, T. The demolding jig according to any one of claims 1 to 7, wherein the component is a durometer type A hardness specified in JIS K 6253 and the hardness is 30 to 90 degrees. This is a demolding method for demolding a cylindrical rubber product formed by using a transfer molding die provided with an oblique knurled groove on the cavity surface from the transfer molding die.
Using the demolding jig according to any one of claims 1 to 8,
The rotating shaft is inserted into the inner peripheral surface of the outer cylinder, a roller ball is fitted into the concave groove of the outer cylinder, and the tip end portion of the outer cylinder is pressed against one end surface of the rubber product.
The outer cylinder is rotated along the diagonal knurled groove by advancing the roller ball along the concave groove while pushing the rotating shaft into the outer cylinder.
Demolding characterized by pushing up the formed rubber product in the molding cavity from one end face toward the other end face while rotating the rubber product by the rotation of the outer cylinder. Method.

Images