JP2010255678A - Method of manufacturing elastic bush and elastic bush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an elastic bush and the elastic bush manufactured by its method, capable of effectively preventing generation of an end surface burr to the periphery of an outer cylinder including a tolerance on the length and a thickness without arranging a special seal member into a mold. <P>SOLUTION: When manufacturing the elastic bush having an outer cylinder 1 and a cylindrical elastic body joined to an inner peripheral surface of the outer cylinder, a cope 13 and an anvil 11 are respectively contacted in a surface with tapered surfaces 5 and 6 respectively formed to the inside in the axial direction and the inside in the radial direction, under a virtual straight cylinder attitude formed in a straight pipe shape by raising up a flange 4 in a corner part in closest vicinity to a joining area of the elastic body in both end parts in the axial direction of the outer cylinder 1 arranged in an upright attitude in the mold and having the flange 4 in one end art, and are put in a seal state of being pressed in the vertical direction, An elastic body material is injected and filled into a cavity 14 partitioned in the mold, and an unvulcanized bush is molded by integrating its elastic body material into the outer cylinder 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes an outer cylinder and a cylindrical elastic body joined to the inner peripheral surface thereof, for example, a rubber elastic body, and a rigid inner cylinder joined to the inner peripheral surface of the elastic body. The present invention relates to a method of manufacturing an elastic bush and an elastic bush manufactured by the method, and in particular, the generation of so-called end-face burrs caused by wraparound adhesion of a rubber elastic body or the like to an unnecessary portion of an outer cylinder. We propose a technology to prevent this.

  For example, in an elastic bush used for use as an anti-vibration bush for a vehicle, an anti-vibration mount, etc., a rubber elastic body or the like adheres to an unnecessary portion of the outer cylinder from the viewpoint of ensuring performance and appearance quality. It is required to prevent the occurrence of end face flash. Therefore, if end face flash is observed on the elastic bushing as a product, the end face flash is removed by buffing or blasting. It becomes necessary to do.

  Therefore, in order to eliminate the work of removing the generated end face beam and reduce the number of work steps and improve the production efficiency, Patent Document 1 describes a mold for filling a rubber material and vulcanizing the rubber material. In the apparatus, a shape memory alloy is disposed at a contact portion of the upper die or the lower die with respect to the inner cylinder or the outer cylinder as an insert, and the inner and outer cylinders and the inner surface of the mold are connected by the pseudoelastic effect of the shape memory alloy. A technique for reducing the occurrence of flash by close contact is disclosed.

JP-A-5-237867

  However, in this prior art, the shape memory alloy is bent or damaged due to repeated deformation, so that it is difficult to maintain the pseudoelastic effect of the shape memory alloy over a long period of time. there were.

  An object of the present invention is to solve such problems of the prior art, and the object of the present invention is to scatter an end face around an outer cylinder including tolerances for length and thickness. It is an object of the present invention to provide a method for manufacturing an elastic bushing that can effectively prevent the occurrence of the occurrence of the above without providing a special seal member or the like in the mold, and an elastic bushing manufactured by the method.

  An elastic bushing manufacturing method according to the present invention comprises an outer cylinder and a cylindrical elastic body, for example, a rubber elastic body, which is bonded to the inner peripheral surface of the outer cylinder by vulcanization bonding, adhesive bonding, or the like. In manufacturing an elastic bush that may have an inner cylinder made of a rigid material joined in the same way to the inner peripheral surface of the body, it is placed in an upright position in the mold and has a flange at one end. At least one end of the outer cylinder in the axial direction, and at the corner located closest to the joining area of the elastic body, it is formed toward the outer side in the axial direction and the inner side in the radial direction under the straight cylinder posture. At least one of the upper die and the lower die is brought into surface contact with the taper surface, and an elastic body material is injected and filled into a cavity defined in the molding die as a sealed state pressed in the vertical direction. The elastic material, adhesive Through, or in shaping the unvulcanized bush is integrated without intervention.

Here, the term “straight cylinder posture” means an upright posture of the outer cylinder when the outer cylinder does not have a flange, and the peripheral edge of the flange when the outer cylinder has an outward flange. When a taper surface is provided in the region, it means a virtual posture in which a flange is raised to form a straight tube.
Even in the case where the outer cylinder has an outward flange, the corner located closest to the joining area in the relationship with the joining area of the elastic body corresponds to the bent base of the flange. In some cases, the actual upright attitude of the flanged outer cylinder is referred to as a “straight cylinder attitude”.
Further, when the outer cylinder has an outward flange with an expansion angle of less than 90 ° with respect to the central axis, when providing a tapered surface in the peripheral edge area of the flange, similarly to the case with the outward flange. Shall be handled.

  In such a method, more preferably, the upper die and the lower die are brought into surface contact with the tapered surfaces formed at the respective end portions of the outer cylinder, and the sealed state is pressed in the vertical direction.

  Further, in the case where the outer cylinder has an outward flange that expands with respect to the central axis at one end thereof, and when the tapered surface is provided in the peripheral area of the flange, the tapered surface is used as the reality of the outer cylinder. Under the upright posture, it is formed toward the outer side in the axial direction and the outer side in the radial direction, and either one of the upper die or the lower die is brought into surface contact with this tapered surface, and the seal state is pressed in the vertical direction. Is preferred.

  Moreover, it is preferable that the outer cylinder is made of a synthetic resin in order to reduce the weight of the manufactured elastic bushing itself.

  Regarding the tapered surface, the inclination angle of the tapered surface with respect to the central axis under the straight cylinder posture is in the range of 10 to 60 °, and the width of the tapered surface is in the range of 0.5 to 5 mm. Is preferred.

  By the way, the elastic bushing of the present invention is an unvulcanized bush formed by any of the above methods, for example, a molding die, when the elastic material is a rubber composition or the like in the above-described method. It is cured by vulcanization in a vulcanization mold that also serves as a vulcanization mold, or in a vulcanization mold that is provided separately from the mold.

  In the method for producing an elastic bushing according to the present invention, the upper and lower sides of the mold are placed under a state in which the outer cylinder is placed in an upright posture in advance in the mold, regardless of whether the outer cylinder is made of metal or resin. At the time of clamping, at least one of them is brought into surface contact with a tapered surface provided on the outer cylinder, and at least the height and thickness of the outer cylinder are obtained by making the tapered surface pressed in the vertical direction. Even if there is a manufacturing error within tolerance on one side, the tapered surface of the outer cylinder can be pressed with a sufficiently large force with a sufficiently large contact area on at least one of the upper and lower molds. The mold that comes in contact with it can provide an excellent sealing function, and even if a large vertical force acts on the tapered surface of the outer cylinder, the force is also applied to the horizontal direction in the outer cylinder. Effectively distributed It is possible still to ensure a high sealing capability, of the outer tube, it is possible to effectively prevent the damage caused by the action of an external force.

For example, when an outer cylinder having an outward flange at the upper end is simply sandwiched vertically between the upper surface peripheral area of the flange and the lower end of the outer cylinder with an upper and lower mold, the outer cylinder is pushed up against the outer cylinder. If the force becomes too large, damage to the protruding base of the flange tends to occur. The elastic material injected into the cavity and unable to exert its function enters between the outer peripheral surface of the outer cylinder having sufficient dimensions and the inner peripheral surface of the mold facing the surface, There was a problem that it was easy to adhere and form an end face flash.
In addition, when pressing the upper peripheral area of the flange downward with the upper mold, the peripheral area may not be sufficiently sealed due to tolerances such as the height of the outer cylinder and the thickness of the flange. If the shortage is to be compensated for by increasing the contact area between the flange and the upper die, there is a problem that the product size cannot be increased due to the increase in the outer diameter of the flange.

On the other hand, in the method according to the present invention, the lower end of the similar outer cylinder exerts an upward force obliquely upward under the contact of the lower die with the taper surface in a sufficiently large area, By dispersing the force in each direction, it is possible to effectively prevent the concentration of a large thrust force on the projecting base portion of the flange to the projecting base portion of the flange, and to exhibit an excellent sealing function.
And for the upper surface peripheral area of the flange, by exerting a diagonally inwardly downward force under contact with a sufficiently large area on the upper die, the outer cylinder height, flange thickness, etc. Even if there is a processing error within the tolerance range, a sufficient contact area of the upper die to the tapered surface is ensured, and a sufficient sealing function can be exhibited without increasing the flange diameter. be able to.

Here, when the outer cylinder does not have a flange, at least one of the upper mold and the lower mold on the tapered surface of at least one end portion, diagonally downward force and / or diagonally upward upward By applying this force, the vertical force is effectively distributed under a large contact area between the taper surface and the mold, ensuring excellent sealing function without fear of damage to the outer cylinder. .
Again, a sufficiently large contact area between the tapered surface and the mold can be secured within the range of the thickness tolerance of the outer cylinder.
The height tolerance can be dealt with by making a mold assuming the lower limit of the thickness tolerance. On the other hand, with respect to the upper limit of the thickness tolerance, it is possible to effectively prevent damage to the protruding base portion of the outward flange by making the die contact with the tapered surface.

  By the way, in such a method, when the upper and lower molds are brought into surface contact with the respective tapered surfaces formed at the respective end portions of the outer cylinder, and when the sealing state is pressed in the vertical direction, As compared with the case where the sealing function based on the tapered surface is exhibited only at one end portion of the outer cylinder, it is possible to more effectively prevent the occurrence of end face flash.

  In addition, here, one of the upper mold and the lower mold is formed on the peripheral area of the normal outward flange provided at one end portion of the outer cylinder toward the outer side in the axial direction and the outer side in the radial direction. When making the seal state pressed in the vertical direction, as described above, the taper surface is slanted inwardly under the sufficient contact area of the upper die with the taper surface. A large downward force or a contact of the lower die with the taper surface can exert a large oblique upward force on the taper surface. In addition, since it can be secured sufficiently large, it is possible to exhibit an excellent sealing function and to effectively prevent the occurrence of end face flash.

  Also, when the outer cylinder is made of synthetic resin, if an attempt is made to deal with the occurrence of edge flash by secondary processing such as buffing or blasting, the outer cylinder itself will be scratched and undesired. In addition to an increased risk of becoming a non-defective product, damage to the protruding base portion of the flange is more likely to occur as described above, so that the invention of this manufacturing method can be made more effective.

Furthermore, when the inclination angle of the taper surface with respect to the central axis is in the range of 10 to 60 ° and the width of the taper surface is in the range of 0.5 to 5 mm, a large contact area between the mold and the outer cylinder is obtained. Can be ensured, and the occurrence of flash can be more effectively prevented.
On the other hand, if it is out of the above range, it is difficult to sufficiently prevent the occurrence of flash, and the risk of damage to the resin outer cylinder increases.

  In the elastic bushing of the present invention formed by vulcanizing an unvulcanized bush formed by any of the above methods, the occurrence of end face flash is effectively prevented based on the formation of a tapered surface on the outer cylinder. The influence of the tapered surface on the performance of the elastic bush can be made substantially zero.

It is a longitudinal cross-sectional view which illustrates the elastic bush manufactured by the method concerning this invention. It is the same sectional view showing other elastic bushes. It is a longitudinal cross-sectional view which shows the clamping state of the method which concerns on this invention. It is a principal part expanded sectional view which illustrates the effect | action of the upper mold | type and a lower mold | type with respect to each taper surface.

  FIG. 1 is a longitudinal sectional view in a plane including a central axis, illustrating an elastic bush manufactured by the method according to the present invention, in which 1 is an outer cylinder that can be made of metal, synthetic resin, or the like. 2 shows, for example, an inner cylinder made of a rigid material concentrically with the outer cylinder 1, and 3 shows an inner cylinder 2, 1 with or without an adhesive layer, respectively. An elastic body, for example, a rubber elastic body, which is bonded and connects them over the entire circumference, for example, is shown.

Here, the outer cylinder 1 has an outward flange 4 at 90 ° with respect to the central axis at the upper end thereof, and this flange 4 is closest to the peripheral area, that is, the joining area of the rubber elastic body 3. The taper surface 5 is formed at each of the corner portions positioned in the illustrated orientation toward the outer side in the axial direction and the outer side in the radial direction.
The tapered surface 5 can be formed over the entire thickness of the flange 4, but in the figure, the tapered surface 5 is formed over almost half of the flange thickness in order to avoid the formation of sharp edges on the flange 4. Provided.

  Under the virtual “straight cylinder posture” of the taper surface 5 that causes the flange 4 to be a straight tube, the taper surface 5 faces both the outer side in the axial direction and the inner side in the radial direction.

And here, the lower end of the outer cylinder 1 is also located at the inner peripheral corner of the lower end closest to the joining region of the elastic body 3 to the inner peripheral surface thereof, on the axially outer side and the radial side. It has the taper surface 6 formed toward each.
The outer peripheral surface of the outer cylinder 1 is formed in a taper shape that tapers toward the lower end of the elastic bushing so as to facilitate press-fitting of the elastic bushing into a mounting sleeve (not shown) under reduced diameter deformation.

  In the meantime, as shown in FIG. 1, the tapered surface 5 is formed in the peripheral area of the outer cylinder 1, but when the elastic body 3 is joined only to the inner peripheral surface of the outer cylinder 1, the flange 4 is folded. The upper end corner of the outer cylinder 1 serving as a curved base can be a corner located closest to the joining region of the elastic body 3, and in this case, the upper end corner of the outer cylinder 1 in the upright posture. In addition, as illustrated in FIG. 2, similarly to the case where the outer cylinder 1 is a straight pipe, tapered surfaces facing the axial direction outer side and the radial direction inner side are formed.

  The elastic bush configured as described above has the tapered surfaces 5 and 6 in the outer cylinder 1 and is still free from vibrations in the axial direction and in the direction intersecting the direction under the action of the elastic body 3. Antivibration function as expected.

  Here, in manufacturing the elastic bushing having the structure as shown in FIG. 1, for example, as shown in a longitudinal sectional view in FIG. The inner cylinder 2 is fitted and arranged around the central projection 11a of the eleventh, and the outer cylinder 1 is fitted inside the intermediate mold 12 with a slight clearance from the inner peripheral surface of the intermediate mold. The upper mold 13 is clamped with respect to the lower mold 11 and the middle mold 12 in this state.

  By this clamping, a cavity 14 for molding a required elastic body is defined between the inner and outer cylinders 2, 1 and the upper and lower molds 13, 11, and the upper mold 13 with respect to the outer cylinder 2 is separated. Based on the downward pressing force and the upward push-up force of the lower mold 11, the tapered surface 5 of the flange 4 at the upper end in the drawing covers a sufficiently large area with the upper mold 13 as illustrated in FIG. 4A. 4B, the inner peripheral side taper surface 6 at the lower end portion of the outer cylinder 2 is illustrated as a result of contact with each other and reliably sealed by a force radially inward and downward in the axial direction. As such, the force that is in contact with the lower die 11 over a sufficiently large area and that is directed radially outward and upward in the axial direction is also reliably and sufficiently sealed.

  Therefore, after that, a molten elastic material such as a rubber material is injected and filled into the cavity 14 under pressure, and the elastic material is injected into the inner and outer cylinders 2 and 1 with the adhesive layer interposed therebetween, or In forming an unvulcanized bush that is integrated without intervention, the wraparound flow of the elastic material over the flange taper surface 5 causes the upper die 13 to contact the taper surface 5 with a large force over a large area. And the wraparound flow of the elastic material over the lower end tapered surface 6 of the outer cylinder 1 is between the outer peripheral surface of the outer cylinder 1 and the inner peripheral surface of the intermediate mold 12. Regardless of whether or not there is a clearance, the lower die 11 that contacts the tapered surface 6 with a large force over a large area is effectively prevented.

  In this case, the downward pressing force of the upper die 13 and the upward thrusting force of the lower die 11 are effectively distributed in each direction as horizontal component forces and the like by the respective taper surfaces 5 and 6. However, if the outer cylinder 1 is made of metal and is made of synthetic resin, the load applied to the protruding base of the outer cylinder flange, etc. The possibility of occurrence of damage due to concentration or the like can be sufficiently eliminated.

  Thus, in the case of an unvulcanized bush molded in this way, when it is vulcanized in a mold, vulcanization occurs in a vulcanization mold that is separate from the mold, and so-called end flash is generated. Since it will always be sufficiently prevented and ex-post deburring is not necessary, the outer cylinder can be removed by eliminating the work process and man-hours to remove the flash by buffing, blasting, etc. The occurrence of damage to the outer cylinder when made of a rigid resin can be sufficiently prevented.

  3 and 4, taper surfaces 5 and 6 are formed on both the peripheral edge of the flange 4 and the inner peripheral surface of the lower end of the outer cylinder 4, but only one of them is a tapered surface. It is also possible to form this, and this also makes it possible to effectively exhibit an excellent sealing function due to the provision of the tapered surface.

The above is a case where an elastic bushing having a form in which the flange 4 is omitted from the outer cylinder 1 is formed in the mold as illustrated in FIG. 2, and the upper end surface of the outer cylinder 1 is held with the upper mold 13. The same applies to the case where the taper surface and the lower end taper surface of the outer cylinder 1 are pressed in the vertical direction by the lower die 11, and this also applies to each taper surface without damage to the outer cylinder 1. Generation of end face flash can be effectively prevented by exhibiting a high sealing function.
In this case, the tapered surface can be formed only on either the upper end or the lower end of the outer cylinder 1.

  1, 3, and 4 (a), the elastic body 3 is joined to the upper surface of the flange 4, but the elastic body 3 is attached to the cylindrical portion of the flanged outer cylinder 1. When joining only to the inner peripheral surface, it is possible to provide an obliquely inwardly upward tapered surface at the upper end corner portion of the outer cylinder 1 as described above. Can be exerted in a sealed state by pressing downward with a high sealing function.

  In the above description, the taper surface provided in the outer cylinder 1 has an angle of inclination of the outer cylinder 1 with respect to the central axis under the straight cylinder posture described above in the range of 10 to 60 °. In addition, the width of the tapered surface should be in the range of 0.5 to 5 mm, ensuring a large contact area between the mold and the outer cylinder without fear of damage to the resin outer cylinder, etc. It is preferable for preventing it more effectively.

DESCRIPTION OF SYMBOLS 1 Outer cylinder 2 Inner cylinder 3 Rubber elastic body 4 Flange 5, 6 Tapered surface 11 Lower mold | type 11a Center part 12 Middle mold | type 13 Upper mold | type 14 Cavity

Claims (6)

In producing an elastic bushing comprising an outer cylinder and a cylindrical elastic body joined to the inner peripheral surface of the outer cylinder,
The outer cylinder, which is arranged in an upright position in the mold and may have a flange at one end, has at least one end in the axial direction at the corner closest to the joining area of the elastic body, Under the taper surface formed toward the outer side in the axial direction and the inner side in the radial direction, at least one of the upper die and the lower die is brought into surface contact, and as a sealed state pressed in the vertical direction, A method for manufacturing an elastic bushing, in which an elastic material is injected and filled into a cavity to be partitioned, and an unvulcanized rubber is formed by integrating the elastic material into an outer cylinder.   The method for producing an elastic bush according to claim 1, wherein each of the upper die and the lower die is brought into surface contact with a tapered surface formed at each end portion of the outer cylinder, and the seal is pressed in the vertical direction.   One of the upper and lower molds is brought into surface contact with the tapered surface formed toward the outer side in the axial direction and the outer side in the radial direction on the peripheral area of the outward flange provided at one end of the outer cylinder, and The method for producing an elastic bush according to claim 1 or 2, wherein a sealing state is applied in a direction pressed.   The method for producing an elastic bush according to any one of claims 1 to 3, wherein the outer cylinder is made of a synthetic resin.   The tilt angle of the tapered surface with respect to the central axis under the straight cylinder posture is in a range of 10 to 60 °, and the width of the tapered surface is in a range of 0.5 to 5 mm. A method for producing an elastic bush according to claim 1.   An elastic bush formed by vulcanizing an unvulcanized rubber molded by the method according to claim 1.

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