JPS61254318A - Manufacture of molded part with outer tubular fitting - Google Patents

Abstract

PURPOSE:To obtain a molded part, which is favorable in yield and for the surface to be finished later and has few flash, by a method wherein an enclosed space surrounded by a first split mold, a second split mold and the inner peripheral surface of an outer tubular fitting is formed by elastically deforming the outer tubular fitting in such a manner that both the end surfaces of the outer tubular fitting are pressed by the first abutting surface of the first split mold and by the second abutting surface of the second split mold and, after that, raw material is poured in the enclosed space. CONSTITUTION:Firstly, an outer tubular fitting 5 is placed in the cavity of a molding tool 1 and, after that, the molding tool 1 is closed. At that time, one end surface 50 of the outer tubular fitting 5 is pressed by a first abutting surface 26 and, at the same time, the other end surface 51 of the outer tubular fitting 5 is pressed by a second abutting surface 34. As a result, the peripheral wall of the outer tubular fitting 5 is curved so as to position its central portion outwards in order to form an enclosed space 6 surrounded by a first split mold 2, a second split mold 3 and the inner peripheral suface of the outer tubular fitting 5. Secondly, un-vulcanized compounded rubber is poured through the inlet of the first split mold 2 into the enclosed space 6. The poured un-vulcanized compounded rubber is vulcanized and solidified by the heat transmitted from the molding tool 1 heated up to high temperature so as to from a rubber molded part 7 with the outer cylindrical fitting 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a molded product having an outer cylindrical metal fitting. The present invention can be used, for example, in a method for manufacturing engine mount insulators and rubber bushings used in automobiles.

[Prior Art] A method for manufacturing a rubber molded product having an outer cylindrical metal fitting generally includes a step of placing the outer cylindrical metal fitting in a mold and clamping the mold, and placing an unvulcanized compound in the cough mold. A step of forming a rubber molded product with an outer cylindrical fitting by injecting and solidifying rubber, and then a step of opening the mold and taking out the rubber molded product with the outer cylindrical fitting from the mold are carried out in sequence. This was done by doing this. Here, in the above-mentioned mold, as a measure to prevent the mold from twisting when the mold is clamped, the part of the mold where the outer cylindrical fitting is placed is set to be slightly larger than the dimensions of the outer cylindrical fitting. .

[Problems to be Solved by the Invention] In the manufacturing method using the mold described above, when the unvulcanized compounded rubber is injected into the mold, the unvulcanized compounded rubber contacts both end surfaces of the outer cylindrical metal fitting. Unvulcanized compounded rubber may leak from a small gap between the mold surface and the mold surface, and unvulcanized compound rubber that leaks from this gap may also leak onto the mold surface, resulting in a large amount of debris. Become. If there is a large amount of paris, it is disadvantageous in terms of yield and post-finishing.

The present invention has been made in order to solve the above-mentioned problems, and its purpose is to manufacture a molded product with an outer cylindrical fitting that has less flaking and is advantageous in terms of yield and post-finishing. We are here to provide you with a method.

[Means for Solving the Problems] The manufacturing method according to the present invention includes: a first split mold having a first contact mold surface that contacts one end surface of the outer cylindrical metal fitting; and a first split mold that abuts the other end surface of the outer cylindrical metal fitting. By using a mold having a second split mold having a second abutting mold surface in contact with each other, placing the outer cylindrical fitting in the mold, and clamping the mold, both ends of the outer cylindrical fitting are The surface is pressed by the first abutting mold surface and the second abutting mold surface, the peripheral wall of the outer cylindrical metal fitting is elastically deformed and curved, and both end surfaces of the curved outer cylindrical metal fitting and the first abutting mold surface are pressed together. a step of sealing between the surface and the second abutting mold surface and forming a sealed space surrounded by the first divided mold, the second divided mold, and the inner circumferential surface of the outer cylindrical metal fitting; A step of injecting the raw material into the sealed space and solidifying it to form a molded product having the outer cylindrical metal fitting, and then a step of opening the cough mold and taking out the molded product are carried out in order. It is characterized by:

The mold used in the manufacturing method according to the present invention has a first divided mold and a second divided mold. The first split mold has a first contact mold surface that contacts one end surface of the outer cylinder fitting.

The second split mold has a second abutting mold that abuts the other end surface of the outer cylindrical metal fitting. Here, one end surface and the other end surface of the outer cylinder metal fitting are
It means each end face of both end faces in the axial direction of the outer cylindrical metal fitting.

The outer cylindrical metal fitting needs to be made of a material that can be elastically deformed in order to be curved. Such materials include metal materials such as steel.

This outer cylindrical metal fitting generally has a cylindrical shape. The thickness of the peripheral wall of the outer cylindrical metal fitting is appropriately set depending on the surroundings such as the material of the outer cylindrical metal fitting, the clamping force of the mold, and the degree of sealing required.

The mold surfaces of the first divided mold and the second divided mold that define the shape of the molded product are usually formed within a range surrounded by the first abutment surface and the second abutment surface, respectively. Generally, the first split mold is formed in one piece, but in some cases, it may be formed in plural pieces. Similarly, the second split mold is generally formed in one piece, but may be formed in plural pieces depending on the case. The mold is generally connected to a drive source such as a hydraulic cylinder, and by driving the drive source, the mold can be opened and closed.

In the manufacturing method of the present invention, the outer cylindrical metal fitting is placed in a cavity within the mold. In this case, the outer cylindrical metal fitting may be placed in either the first divided mold or the second divided mold. Depending on the type of molded product, for example, if the molded product is a rubber bushing, an inner cylindrical metal fitting may be placed in the mold in addition to the outer cylindrical metal fitting.

After the outer cylindrical metal fitting is arranged in this way, by clamping the mold, one end surface of the outer cylindrical metal fitting is pressed by the first abutting mold surface, and the other end surface of the outer cylindrical fitting is pressed against the second abutting mold surface. Press with the mold surface. That is, the outer cylindrical metal fitting is pressed from both sides in the axial direction. The mold clamping speed may be constant from the time of start to the time of completion of mold clamping. In some cases, the mold clamping speed may be reduced immediately before mold clamping is completed.

In this way, damage to the outer cylinder fitting during mold clamping can be suppressed.

When both end surfaces of the outer cylindrical metal fitting are pressed as described above, the peripheral wall of the outer cylindrical metal fitting is elastically deformed and slightly curved.

In this case, the peripheral wall of the outer cylindrical metal fitting may be curved inwardly or outwardly. In this state where the outer cylindrical metal fitting is elastically deformed, the restoring force of the outer cylindrical metal fitting due to the elastic deformation creates a seal between the one end surface of the outer cylindrical metal fitting and the first contact mold surface, and A seal is also formed between the other end surface of the cylindrical metal fitting and the second abutting die surface. As a result of such sealing, a sealed space surrounded by the first split mold, the second split mold, and the inner peripheral surface of the outer cylinder fitting is formed. Note that the sealed space communicates with a sprue hole and the like through which raw materials are injected into the sealed space.

Note that both end surfaces of the outer cylindrical metal fitting may be tapered surfaces such that the axial length of the outer cylindrical metal fitting increases toward the outer surface of the peripheral wall of the outer cylindrical metal fitting. In this case, the first abutting die surface and the second abutting die surface are also shaped to correspond to this Taber surface. With such a configuration, when the first split mold and the second split mold are clamped, the peripheral wall of the outer cylindrical metal fitting is more likely to curve laterally due to the wedge principle.

Once the sealed space is formed as described above, the raw material is then injected into the sealed space through the injection hole formed in the mold to fill the sealed space with the raw material. Typical raw materials to be injected include unvulcanized compounded rubber and resin. When the injected raw material solidifies, the solidified raw material and the outer cylindrical metal fitting are integrally bonded, thereby forming a molded product having the outer cylindrical metal fitting. If the injected raw material is unvulcanized compounded rubber, the raw material is generally solidified by heating the mold to the vulcanization temperature.

Next, the mold is opened and the molded product is taken out from the mold. The molded product is generally removed by operating an extrusion bottle.

If the molded product is a rubber bushing, etc., once the molded product with the outer cylindrical fitting is removed from the mold, in order to improve the spring constant in the axial direction, the spring constant in the direction perpendicular to the axis, etc.
Generally, the molded product is squeezed with a jig so that the diameter of the outer cylindrical metal fitting is reduced.

[Effects of the Invention] According to the manufacturing method of the present invention, both end surfaces of the outer cylindrical metal fitting are pressed by the first abutting die surface of the first split mold and the second abutting die surface of the second split mold, and the outer cylindrical fitting is pushed out. By elastically deforming the cylindrical metal fitting, a sealed space surrounded by the first split mold, the second split mold, and the inner peripheral surface of the outer cylindrical metal fitting is formed, and the raw material is injected into this sealed space.

Therefore, during molding, it is possible to prevent the raw material from leaking between the one end surface of the outer cylindrical metal fitting and the first abutting mold surface, and similarly, it is possible to prevent the raw material from leaking between the other end surface of the outer cylindrical metal fitting and the second abutting mold surface. It is possible to prevent raw materials from leaking between the surfaces. Therefore, the occurrence of paris can be suppressed compared to the conventional method. Therefore, it is possible to improve the yield and simplify or omit the post-finishing process.

[Example] The drawings show an example of the manufacturing method according to the present invention. 1st
The figure is a cross-sectional view of the mold with the outer cylindrical metal fitting placed inside the mold, and Figure 2 is a cross-sectional view of the mold just before the mold is clamped with the outer cylindrical metal fitting placed inside the mold. It is a diagram.

The outer cylindrical metal fitting 5 used in the manufacturing method according to this embodiment has a cylindrical shape. The outer cylindrical metal fitting 5 is made of STKMllA, and is elastically deformable so as to hang. The outer cylinder fitting 5 has one end surface 50 and the other end surface 51 in the axial direction.

The mold 1 used in this manufacturing method consists of a first split mold 2 and a second split mold 2.
It has a split type 3. The first split mold 2 includes an upper mold 20 in which a runner hole 21 and an injection hole (not shown) are formed, and a middle mold 23 in which a sprue hole 22 communicating with the runner hole 21 is formed.
has. Note that the runner hole 21 is formed in the mold parting surfaces of the upper mold 20 and the middle mold 23. One sprue hole 22 is medium size 23
It is formed almost parallel to the mold opening direction, penetrating through the mold. This sprue hole 22 is formed so that its diameter becomes smaller as it goes toward the cavity 4, with the tip end 22a having the smallest diameter. The middle mold 23 has a protrusion 25 . The end 25a of the protrusion 25 has an arcuate curved surface. Furthermore, a first abutting mold surface 26 that comes into contact with one end surface 50 of the outer cylinder fitting 5 is formed on the outside of the end portion 25a. First contact mold surface 2
Although not shown, 6 has a ring shape.

The second split mold 3 has a middle mold 30, 31 and a lower mold 32.

The cavity that defines the shape of the molded product is medium-sized 23.30.
31 and is formed on the mold parting surface with the lower mold 32. Lower mold 32
is the second contact mold surface 34 that comes into contact with the other end surface 51 of the outer cylinder fitting 5
have. Although not shown, the second abutting mold surface 34 has a ring shape. The dimension L1 between the first abutting mold surface 26 and the second abutting mold surface 34 during mold clamping is slightly smaller than the axial length dimension L2 of the outer cylinder fitting 5 (Ll < 12)
. The lower die 32 has a protrusion 33. The protrusion 33 is the protrusion 2
5, and the end portion 33a thereof is an arcuate curved surface.

In the manufacturing method according to this embodiment, first, with the mold 1 opened, the outer cylindrical metal fitting 5 is placed in the cavity of the mold 1, as shown in FIG.

Then, the mold 1 is clamped by driving a hydraulic cylinder or the like. Then, one end surface 50 of the outer cylindrical metal fitting 5 is pressed by the first abutting mold surface 26, and the other end surface 51 of the outer cylindrical metal fitting 5 is pressed by the second abutting mold surface 34. As a result, the peripheral wall of the outer cylindrical metal fitting 1 is elastically deformed and curved so that the center portion is located on the outside as shown in FIG. In the curved state, there is a seal between one end surface 50 of the outer tube fitting 1 and the first abutting mold surface 26, and a seal is formed between the other end surface 51 of the outer tube fitting 1 and the second abutting mold surface 34.
A seal will also be placed between the two. Therefore, as shown in Figure 1, the first
A sealed space 6 surrounded by the inner peripheral surfaces of the split mold 2, the second split mold 3, and the outer cylindrical fitting 5 is formed.

Next, unvulcanized compounded rubber as a raw material is injected from the injection hole of the first split mold 2 of the mold 1, and the unvulcanized compounded rubber is injected into the sealed space 6 through the runner hole 21 and the sprue hole 22. inject. The injected unvulcanized compounded rubber is vulcanized and solidified by the heat transmitted from the mold 1 heated to a high temperature.

As a result, a rubber molded product 7 having an outer cylindrical metal fitting 5 is formed.

After that, the upper mold 20 and the middle mold 23 are opened, and a runner formed by filling the runner hole 21 with rubber and a sprue formed by filling the sprue hole 22 with rubber are placed on the upper mold 20 side. At the same time, the tip 22a of the sprue hole 22 and the molded product 7 are separated. Next is medium size 23.30
, 31 are opened, and the rubber molded product 7 is taken out by extrusion using an extrusion bottle (not shown).

According to the manufacturing method according to this embodiment, one end surface 50 of the outer cylinder fitting 5 is pressed by the first abutting mold surface 26, and the other end surface 51
is pressed by the second abutting mold surface 34 to elastically deform the outer cylinder fitting 5 to form a sealed space 6.
The structure is such that unvulcanized compounded rubber is injected into the inside. Therefore, even when unvulcanized compounded rubber is injected under high pressure, leakage of the unvulcanized compounded rubber from between the one end surface 50 of the outer cylinder fitting 5 and the first contact mold surface 26 is prevented. It can be prevented.

Similarly, leakage of unvulcanized compounded rubber from between the other end surface 51 of the outer cylinder fitting 5 and the second abutting mold surface 34 can also be prevented. Therefore, it is possible to prevent the unvulcanized rubber compound from flowing out into the space 55 outside the outer cylinder fitting 5.
and the middle die 30, the middle die 23 and the middle die 31, the middle die 30 and the lower die 32, the middle die 31 and the lower die 32.
It is possible to prevent unvulcanized compounded rubber from flowing out onto the mold cutting surface. Therefore, generation of flakes can be suppressed compared to the conventional method, which is advantageous in terms of yield and post-finishing process.

[Brief explanation of the drawing]

The drawings show one embodiment of the manufacturing method according to the present invention.
The figure is a sectional view showing a state in which the outer cylindrical metal fitting is placed in the mold and the mold is clamped, and Figure 2 is a sectional view just before the outer cylindrical metal fitting is placed in the mold and the mold is clamped. FIG. 3 is a perspective view of a rubber molded product having an outer cylindrical metal fitting. In the figure, 1 is a mold, 2 is a first split mold, 3 is a second split mold,
5 is an outer cylindrical metal fitting, 50 is one end surface of the outer cylindrical metal fitting, 51 is the other end surface of the outer cylindrical metal fitting, 6 is a sealed space, 7 is a molded product, 26 is a first abutting mold surface, and 34 is a second abutting mold. Each side is shown.

Claims (2)

[Claims] (1) A first split mold having a first contact mold surface that comes into contact with one end surface of the outer cylindrical metal fitting, and a second split mold that has a second contact mold surface that comes into contact with the other end surface of the outer cylindrical metal fitting. By using a mold with a mold, placing the outer cylindrical metal fitting in the mold, and clamping the mold, both end surfaces of the outer cylindrical metal fitting are brought into contact with the first abutting mold surface and the second abutting mold surface. Pressing with the mold surface to elastically deform and curve the peripheral wall of the outer cylindrical metal fitting, and sealing between both end surfaces of the curved outer cylindrical metal fitting and the first abutting mold surface and the second abutting mold surface. , forming a sealed space surrounded by the first split mold, the second split mold, and the inner circumferential surface of the outer cylindrical metal fitting; injecting a raw material into the sealed space of the mold and solidifying it; A method for manufacturing a molded article having an outer cylindrical metal fitting, comprising: forming a molded article having the outer cylindrical metal fitting; and then opening the mold and taking out the molded item. (2) The outer cylinder according to claim 1, wherein the mold surfaces of the first split mold and the second split mold are formed within a range surrounded by the first contact surface and the second contact surface, respectively. A method for manufacturing molded products with metal fittings.