JPH0520927Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a sealing structure that can be applied with good results when forming a chamber with different pressure values inside and outside a housing.

(Prior Art) There are various types of chambers with different pressure values inside and outside the housing. An example of this is the chamber of a vacuum casting machine, but other examples include pipes that store or convey fluid under pressure, as well as the compression section of a compressor and tanks that store compressed fluid. It will be done. If the pressure values are different inside and outside the housing,
There is no problem when the housing is formed as a single piece, but if the housing is divided into two parts due to the opening of the vacuum casting machine mold or due to the overall size, and the housing is divided into two parts. When the members are abutted and connected, if the part is not completely sealed, the fluid in the chamber will flow out from that part.

This will be explained in more detail with regard to a vacuum casting apparatus as an example thereof. In Figure 3, 1
is the support frame, which is gate-shaped.
An upper mold 2 and a lower mold 3 are provided inside the support frame 1, and a product is molded in a cavity 4 formed between the upper mold 2 and the lower mold 3. An upper housing 5 is integrally attached to the upper mold 2, and a lower housing 7 is attached to the lower mold 3, which is connected to the upper housing 5 via an O-ring 6 (see FIG. 4). The upper and lower housings 5 and 7 function as partial members that become a housing when combined. An elevating frame 8 is attached to the upper part of the upper housing 5. A cylinder 9 is installed at the top of the support frame 1,
The upper end of the rod 11 is fixed to the piston 10 of the cylinder 9, and the lower end of the rod 11 is connected to the lifting frame 8. 12 is a guide rod.

This device thus constructed operates as follows. That is, the upper mold 2 is closed on the lower mold 3 by the cylinder 9 to form the cavity 4, and the upper housing 5 and the lower housing 7 connected via the O-ring 6 form a chamber 13 partitioned from the outside. do. Then, the inside of this chamber 13 is brought into a negative pressure state, and the product is molded in that state. After molding the product, the cylinder 9 is operated to raise the upper die 2 and the upper housing 5 via the rod 11 and the elevating frame 8. A mold release agent is applied to the inside of the cavity 4 which is opened by this, and the product is extruded and taken out using an extrusion rod (not shown). The sealing performance required of the O-ring 6 in this casting apparatus must be maintained under conditions of high pressing force. As an example, when the outer diameter of the chamber 13 is 2 m,
It is known that it can receive a pressing force of about 10 tons.

(Problems to be Solved by the Invention) The lifting and lowering action of the upper die 2 is repeated for each cycle of casting. For this reason, the O-ring 6 is
Pressing and releasing are repeated frequently under conditions of high seal surface pressure, resulting in constant harsh conditions and a shortened lifespan. Therefore, the use of an O-ring was stopped and the effective sealing area was increased by providing unevenness on the sealing surface.On the other hand, a recess was formed on the opposite side of the unevenness and air pressure was applied to this recess.
There is a method in which the sealing effect of the uneven portion is enhanced by deforming the sealing material (see Japanese Patent Laid-Open No. 88078/1988). However, in this case, an air source is required, and the overall structure becomes complicated and expensive. The present invention has been made with the aim of solving these problems.

(Means for Solving the Problems) As a means for solving the above problems, the present invention provides a housing that is divided into two parts to form chambers having different pressure values inside and outside the housing. a dovetail groove is formed in one abutting part of the housing member, and a dovetail groove is formed in the dovetail groove, the side facing the bottom of the dovetail groove and the other housing member facing each other. Forms a serrated lip on each side,
The lip facing the mating housing member has a sealing structure in which it is slightly inclined toward the outside of the housing.

(Function) With this configuration, when the present invention is applied to a vacuum casting machine or the like where the pressure on the outside of the housing is higher than the inside, the sealing material is installed on the side facing the mating housing member. Since the lip is slightly inclined toward the higher pressure side, this slope effectively prevents the higher pressure outside air from entering into the lower pressure housing interior. become. Further, because the lip itself has elasticity, it deforms to respond to repeated pressing and opening, and therefore, stable sealing performance can be ensured over a long period of time.

(Example) Next, an example will be described in which the present invention is applied to the O-ring part of the device shown in FIG. 3, and FIG. 1 shows only the main parts. A dovetail groove 14 facing downward is formed in 5. This dovetail groove 14 has a dovetail groove 1
A sealing material 15 having sawtooth-like lips 15a is interposed between the portion facing the bottom portion 14a of the housing 4 and the lower housing 7 on the other side. The lip 15a of the sealing material 15 is slightly inclined toward the atmosphere side (to the left in the figure) where the pressure is higher, that is, in the case of vacuum casting in this embodiment. In this way, when fluid tries to enter from the high pressure side to the low pressure side, the lip must first be deformed to the opposite side, so there is resistance and the sealing effect can be enhanced.

In this seal structure constructed in this way, when the mold is opened as shown in FIG. 1, the lip 15a is slightly inclined toward the atmosphere as shown in the figure,
When the mold is closed as shown in the figure, the sealing material 15 is attached to the dovetail groove 14.
As it is pressed inward, the lip 15a becomes further inclined. This causes lip 15a
Since the surface and the surface in contact with this are in close contact, good sealing performance is maintained. In this embodiment, since the upper and lower housing members (upper housing 5 and lower housing 7) are constantly opened and closed, the dimensions of the sealing material 15 are set so that it can move relative to the dovetail groove 14, and the material of the sealing material 15 is also selected. Use materials that maintain appropriate elasticity without being deformed by the temperature during use.

(Effects of the invention) Since the present invention is configured as explained above, it is simple and does not require an external pressure device, and can be used in two vacuum casting machines as explained in the embodiment. When applied to joints between housing members that are divided into two parts, an extremely good sealing effect can be obtained. The O-ring mentioned above requires a large pressing force to achieve sufficient sealing performance, but with the O-ring of the present invention, only a small pressing force is required due to the lip function. ) force can be reduced. Due to the adhesion of the lip, a reliable seal can be achieved without having to maintain high machining accuracy on the sealing surface.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing the essential parts of an embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view showing a different state of the one shown in Fig. 1, and Fig. 3 is a vertical cross-sectional view of an example to which the present invention is applied. 4 are longitudinal sectional views showing an example of a conventional seal structure. 5... Upper housing, 7... Lower housing, 1
3...Chamber, 14...Dovetail groove, 14a...Bottom, 15...Sealing material, 15a...Rip.

Claims (1)

[Scope of utility model registration request] The housing, which forms a chamber with different pressure values inside and outside the housing, is formed by abutting two divided housing members with a sealing material interposed therebetween, and abutting part of one of the abutting parts of the housing member. a groove is formed, a serrated lip is formed in the dovetail groove on a side facing the bottom of the dovetail groove and a side facing the mating housing member, and the lip faces the mating housing member. A seal structure characterized by a structure in which the housing is slightly tilted toward the outside of the housing.