JPS6323131Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to the structure of a plunger head used when pressure-injecting resin into semiconductor devices such as ICs and transistors to seal them using the transfer molding method.

A conventional plunger head structure will be explained with reference to FIGS. 1 and 2. In the figure, 1 is a ram adapter, and a hole 1a and a female thread 1b are formed at its tip. 1c is a spanner hook. Reference numeral 2 denotes a joint, and the upper part of the joint 2 is formed with a shaft 2a and a male thread 2b for fitting and threaded connection with the ram adapter 1, and the lower part thereof is formed with a hole 2c and a female thread 2d. 2e is a spanner hook. Reference numeral 3 designates a plunger head, and a head portion 3a that fits into the inner wall of the chamber 5 is formed at the bottom of the plunger head 3, and the head portion 3a includes:
A recessed hole 3b for screwing the plunger head 3 into the joint 2 is formed for use with a wrench.
3c is a shaft that fits into the hole 2c of the joint 2, and 3d is a male thread that is screwed into the female thread 2d. 4
is a gasket, which has a ring shape, and the inner diameter 4a of the gasket 4 is the same as that of the plunger head 3.
The outer diameter 4b is made to be slightly larger than the inner diameter of the chamber 5.

FIG. 2 shows the state in which the above-mentioned parts 1 to 4 are assembled and inserted into the chamber 5. The outer diameter of the packing 4 is larger than the inner diameter of the chamber 5, but when it is inserted into the chamber 5, it is pressed by the inner wall of the chamber 5, and the outer diameter of the packing 4 becomes equal to the inner diameter of the chamber 5. This presses the inner wall of the chamber 5, increasing the sealing effect. The molding material 6 in the chamber 5 absorbs heat and becomes plasticized in the chamber 5, is pressurized by a plunger, passes through a runner gate, fills the cavity, and seals semiconductor devices such as ICs and transistors with resin.

In such a conventional device, the inner wall of the chamber 5 and the head portion 3 of the plunger head 3 are
Resin leaking from the gap with the outer wall a is poured into the recessed hole 3b.
enters the hole, closes the hole 3b, hardens as a lump,
This hardened resin is very hard and difficult to remove after each molding, and the hardened resin scratches the chamber 5, and these scratches also extend to the plunger head 3 and packing 4, and as a result, the chamber 5 , the life of the plunger head 3 and gasket 4 is shortened. Also, ram adapter 1
There are two centering fitting parts between the chamber 5 and the plunger head 3, A part and B part shown in Fig. 2.
The drawback is that it takes time to align the plunger head 3 with the plunger head 3.

The present invention was developed in view of the shortcomings of the conventional products, and aims to improve the mounting structure of the plunger head to the ram adapter, extend the life of the chamber, plunger head, and packing, and improve the centering method. The purpose is to provide a transfer plunger.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4. In the figure, 7 is a ram adapter, and the ram adapter 7 has the same structure as the conventional one, and has a hole 7a, which is an engagement recess, and a female thread 7b at its lower end, and 7c is a spanner hook. . Reference numeral 8 denotes a tightening ring, which is ring-shaped and has an inner hole 8a having the same diameter as the hole 7a, and a plurality of rod spanner insertion holes 8b formed on the outer periphery.
9 is a patch skin and is the same as the conventional one. Reference numeral 10 designates a plunger head, which includes a head portion 10a that is slidably fitted into the chamber 11, a hole 7a of the ram adapter 7, an inner hole 8a of the tightening ring 8, a shaft portion 10b that fits into the packing 9, and the ram adapter 7. has a male thread 10c screwed into the female thread 7b of the
Further, the shaft portion 10b is formed with a rod spanner insertion hole 10d which is an engagement hole that communicates with the rod spanner insertion hole 8b of the tightening ring 8 when assembled.

The transfer plunger of this embodiment is assembled by fitting the packing 9 and the tightening ring 8 onto the shaft portion 10b of the plunger head 10, fitting the plunger head 10 onto the ram adapter 7, and screwing it in. . Tightening in this case is carried out by rotating the tightening ring 8, aligning the wrench rod insertion hole 8b with the wrench rod insertion hole 10d, inserting a rod spanner (not shown) therein, and rotating the wrench. .

As described above, according to the transfer plunger of the present invention, an engagement hole is formed in the shaft portion of the plunger head, and a tightening ring having an insertion hole that communicates with the engagement hole is fitted into the shaft portion. A rod-shaped fastener is inserted into and engaged with the insertion hole and the engagement hole, and the plunger head is rotated by the fastener to be screwed and fixed to the ram adapter. There is no need for an engagement hole for engaging the fastener in the head part of the head part, and since the head part is flat, resin will not stick here in the form of lumps, and even if it does adhere to some extent, it will not. It can be easily removed by blowing compressed air with an air gun, which has the effect of extending the life of the chamber, plunger head, and packing. Furthermore, since there is only one centering fitting portion between the plunger head and the ram adapter at the C portion in FIG. 4, the centering work is easier than in the conventional structure, and the centering accuracy can be improved.

[Brief explanation of the drawing]

1 and 2 are exploded and assembled views of a conventional plunger head, and FIGS. 3 and 4 are exploded and assembled views of a transfer plunger according to an embodiment of the present invention. 7... Ram adapter, 7a... Fitting recess (hole), 7b... Threaded part (female thread), 8... Tightening ring, 8b... Insertion hole (bar spanner insertion hole), 9...
Packing, 10...Plunger head, 10a...
...Head part, 10b...Shaft part, 10c...Threaded part (male thread), 10d...Engagement hole (spanner insertion hole),
11...Chiyamba.

Claims (1)

[Scope of utility model registration request] It consists of a cylindrical shaft part and a head part which has an outer diameter larger than the shaft part and is slidably inserted into the chamber, and an engagement hole is formed in the side surface of the shaft part, and the end part of the shaft part includes a plunger head with a threaded portion formed therein, an annular packing fitted onto the shaft portion of the plunger head and having an outer diameter slightly larger than the head portion of the plunger head; a tightening ring which is fitted into the shaft on the non-chamber side of the packing and has an insertion hole that is small in diameter and can communicate with the engagement hole of the shaft, and a fitting ring which is fitted with the shaft of the plunger head. a ram adapter having a recess and a threaded portion that engages with the threaded portion of the shaft, the rod-shaped fastener being inserted into and engaged with the insertion hole of the tightening ring and the engagement hole of the shaft, which communicate with each other; A transfer plunger characterized in that the plunger head is rotated by the rod-shaped fastener and is screwed and fixed to the ram adapter.