JPS61154818A - Manufacture of buffer for torsional damper and mold used therein - Google Patents

Abstract

PURPOSE:To prevent positively a recess from being formed in the end of a buffer when it is removed, by cutting the hardened buffer that has filled continuously a supply path and a cavity at a part where the supply path extends into the cavity and that is adjacent to the boundary between a throttled port having a small cross-sectional area and a releasing port having a large cross-sectional area. CONSTITUTION:A damper hub 7 and a damper mass 8 are placed in a mold 1, and a cavity 12 is formed between the damper hub 7 and the damper mass 8. Then, an elastic material 15 containing a vulcanizer into a chamber 13 of a movable mold 6, and by inserting a plunger 14 into the chamber 13 the elastic material 15 is flowed under pressure into the cavity 12 via supply paths 16, 17, 18 of the movable mold 6. The the mold 1 is heated to harden the elastic material 15 in the cavity 12 to mold a buffer 3. After the completion of the molding, the molded item is removed. The elastic material hardened in the paths is cut at about the boundary 19 between a throttled port 17 having a small cross-sectional area and a releasing port 18 having a large cross-sectional area.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a shock absorber for a torsional damper that is attached to a rotating shaft such as a crankshaft of an internal combustion engine and absorbs root vibration of the rotating shaft. Regarding molds.

(Prior Art) Conventionally, a buffer body adhered between the damper bald part and the damper mass of the torsional damper is manufactured as follows. That is, as shown in FIG. 4, a damper hub 34 and an annular damper mass 35 are coaxially arranged in a fixed mold 31, a second fixed mold 32, and a movable mold 33 so as to face each other. A plunger 38 inserted into a chamber 37 of a movable mold 33 is pressurized to inject a rubber material 39 into a cavity 36 formed between the damper hub 34 and the damper mass 35, and the rubber material 39 is heated and cured. The movable mold 33 has a material supply chamber 37 in which the rubber material 39 is press-fitted into the cavity 36.
A next runner 4o is connected to the runner 4o, and a gate 41 is connected to the runner 40 and opens into the cavity 36.

The shape of the gate 41 is as shown in FIG.
Those formed into a narrow diameter tube continuous with the lunch 40,
As shown in FIG. 6, the gate 41 is connected to the launch 40.
There is a friend whose tip is tapered and expanded in diameter.

After molding is completed, when the movable mold 33 and the first fixed mold 31 and second fixed mold 32 are opened, the rubber material 39 that has hardened within the chamber 37, the runner 40, and the gate 41 is removed from the runner 40 and the gate. It breaks at the boundary with 41. The rubber material 39 hardened within the gate 41 is further cut to a predetermined length and remains as a protrusion at the end of the molded buffer.

(Problems to be Solved by the Invention) However, in the case of such a conventional example, as shown in FIG. 5 or FIG. Although the gate 41 and the cavity 36 are clearly continuous without any steps, there is a corner between the gate 41 and the cavity 36. Therefore, when the movable mold 33, the first fixed mold 31, and the second fixed mold 32 are opened after molding is completed, the rubber material 39 that has hardened within the chamber 37, the runner 40, and the goo 41 is removed from the runner 40 and the gate 41. It is easy to break at the boundary between the goo 41 and the cavity 36 without being broken at the boundary between the goo and the cavity . Therefore, the cured rubber material 39 is exposed to the gate 4.
1 and the cavity 36, a recessed hole is formed at the end of the cushioning body after molding. A constant torsional damper in which a recessed hole is formed in the buffer body has a problem in that during use, cracks occur from the recessed hole, causing the shock absorber to quickly lose its function and reduce its durability.

However, in order to avoid this, there were problems in that careful attention was required when releasing the molded product, and workability was poor.

The present invention has been made to solve the problems of the prior art, and its purpose is to prevent dents from forming at the ends of the cushioning body during mold release when molding the cushioning body for torsional dampers. It can reliably prevent the formation of holes, improve the quality of the torsional damper, and
It is an object of the present invention to provide a method for manufacturing a buffer body for a torsional damper that can be easily manufactured and improve workability, and a mold for the same.

(Means for Solving the Problems) Therefore, in order to achieve the above object, the present invention provides the first
In the manufacturing method according to the invention, after the fixed mold and the movable mold are closed, an elastic material is injected into the cavity of the fixed mold through the supply path of the movable mold, and then the elastic material is cured by heating. Later, in a method for manufacturing a torsional damper buffer by releasing a fixed mold and a movable mold, the supply channel and the cavity are continuously filled with the hardened buffer, and the supply channel and the cavity are filled with the hardened buffer. It is a portion that enters the inside and is configured to be cut near the boundary between the aperture port having a small cross-sectional area and the release port having a large cross-sectional area. Furthermore, the mold according to the second aspect of the invention is a mold consisting of a fixed mold having a cavity and a movable mold having a dangerous supply path for injecting an elastic material into the cavity of the fixed mold. The part of the supply path of the movable mold that enters the cavity of the fixed mold is divided into a narrow opening with a small cross-sectional area that is considerably smaller than the cross-sectional area of the non-entering part and located on the side opposite to the cavity, and a large opening that is close to the cavity side. The opening is configured to be divided into a cross-sectional area and a release opening.

(Example) The present invention will be explained below based on the illustrated example. 1st
The figure shows a mold 1 used in the manufacturing method of the present invention.
It is a method for molding a first fixed mold 4 and a second fixed mold.
It consists of a fixed mold 5 and a movable mold 6. As shown in FIG. 3, the torsional damper 2 is constructed by bonding the annular buffer body 3 between a companion damper hub 7 and an annular damper mass 8, which are arranged coaxially so as to face each other. A mounting hole 9 is provided at the center of the damper hub 7 for fixing the damper hub 7 to a rotating shaft (not shown) such as a crankshaft.

The first fixing mold 4 is provided with a protrusion 10 that fits into the mounting hole 9 of the damper hub 7 and fixes the damper hub 7. A second fixed mold 5 joined to this first fixed mold 4
is formed in an annular shape and has an inner diameter equal to the outer diameter of the damper hub 7, and on the inner periphery of the upper end of the second fixed mold 5 is a narrow annular stepped portion 11 into which the damper mass 8 is fitted and fixed. It is provided.

The movable mold 6 is fitted into the second fixed mold 5 to form an annular cavity 12 between the damper hub 7 and the damper mass 8, and the movable mold 6 is fitted with rubber or the like. A chamber 13 is provided for supplying an elastic material of
A plunger 14 is fitted into this chamber 13 .

The movable mold 6 is provided with a supply path for injecting the elastic material 15 supplied into the chamber 13 into the cavity 12, and the portion of the supply path that enters the cavity 12 is non-contact. a narrow cross-sectional area 17 that is considerably smaller than the cross-sectional area of the entry portion 16 and located on the side opposite to the cavity;
It is divided into a release port 18 with a large cross-sectional area near the cavity side. The non-entering portion 16 of the supply path consists of a launch formed in the shape of a tapered Taber tube, and the throttle port 17 located between the non-entering portion 16 and the release port 18 is a very short tubular tube with a small diameter. It consists of a passage.

The release port 18 following the throttle port I7 has a cross-sectional area larger than the cross-sectional area of the throttle port 17, and is formed of a Taber tube-shaped gate with a slightly enlarged diameter at the tip end.

In the above configuration, the cushioning body for a torsional damper is molded as follows using the molding die according to the present invention. That is, as shown in FIG. 1, a damper knob 7 and a damper mass 8 are arranged in a mold l, and a cavity 12 is formed between the damper hub 7 and the damper mass 8. Next, by supplying the elastic material 15 mixed with a vulcanizing agent into the chamber 13 of the movable mold 6 and inserting the plunger 14 into the chamber 13, the inside of the cavity 12 is
The elastic material 1 is supplied through the supply channels 16, 17, 18 of the movable mold 6.
5 is injected under pressure. By heating the mold l, the elastic material 15 in the cavity 12 is hardened, and the buffer body 3 is molded and bonded between the damper hub 7 and the damper mass 8. At that time, an adhesive is applied in advance to the bonding surfaces of the damper hub 7 and the damper mass 8, if necessary.

After the molding is completed as described above, the movable mold 6 and the first fixed mold 4
and the second fixed mold 5 are released to release the molded product. At this time, the elastic material 15 that has hardened within the supply channel is connected to the drawing hole 17 with a small cross-sectional area and the release opening 18 with a large cross-sectional area. Stress is concentrated near the boundary 19 and the cutting occurs. The above aperture flow 17
If it is cut in the middle, it is cut by appropriate means at the boundary between the aperture port 17 and the release port 18 after the mold is released. Therefore,
Finally, the buffer body 3 of the molded torsional damper 2
The specific elastic material 15 hardens within the release port 18 at the injection end and remains as a residual protrusion 20, and when the mold is released, it remains near the boundary 1.
5, a recessed hole is formed in the remaining protrusion 20, so that no recessed hole is formed in the buffer body 3 itself.

(Effects of the Invention) The present invention has the above configuration and operation, and in the method for manufacturing a torsional damper buffer according to the first aspect of the present invention, the supply path and the cavity are continuously filled. The cured and hardened buffer body is cut at the part where it enters the cavity of the supply channel and near the boundary between the aperture opening with a small cross-sectional area and the release opening with a large cross-sectional area, so that the molding is completed. Afterwards, when the mold is released, the elastic material hardened in the supply channel is cut at least near the boundary, and is not cut on the side of the molded buffer body, thereby preventing the formation of recessed holes in the buffer body.

Therefore, a recessed hole is formed in the buffer.

In addition to improving the quality of the torsional damper, it also eliminates the need to take special precautions when demolding, making work easier and improving productivity. has advantages. fe, the mold for a buffer body for a torsional damper according to the second aspect of the present invention can provide a mold used in the above manufacturing method.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a mold for a cushioning body for a torsional damper according to the present invention, FIG. 2 is an enlarged sectional view showing main parts, and FIG. 3 is a sectional view showing a torsional damper. Fig. 4 is a sectional view showing a conventional mold, Fig. 5 is an enlarged sectional view showing the main parts of the same mold, and Fig. 6 is an enlarged sectional view showing another embodiment of the main part of the same mold. be. Explanation of symbols l...Molding mold 4, 5...Fixed mold 6...
Movable type 12... Cavity 16... Non-entering part (supply path) 17... Squeezing port (supply path) 18... Release port (supply path) 19... Boundary

Claims (2)

[Claims] (1) After the fixed mold and the movable mold are closed, an elastic material is injected into the cavity of the fixed mold through the supply path of the movable mold, and after the elastic material is heated and hardened, the fixed mold and the movable mold are closed. In the method of manufacturing a buffer body for a torsional damper by releasing from the mold, the supply channel and the cavity are continuously filled with the hardened buffer body, and the part of the supply channel that enters the cavity is A method for producing a torsional damper shock absorber, characterized in that the buffer body is cut near the boundary between a throttle opening having a small cross-sectional area and a release opening having a large cross-sectional area. (2) A mold consisting of a fixed mold having a cavity and a movable mold having a supply path for injecting an elastic material into the cavity of the fixed mold, wherein the fixed mold has a supply path for injecting an elastic material into the cavity of the movable mold. The part that enters the cavity is divided into an aperture opening with a small cross-sectional area that is considerably smaller than the cross-sectional area of the non-entering part and located on the side opposite to the cavity, and an opening opening with a large cross-sectional area near the cavity side. A mold for a shock absorber for a torsional damper.