JPS62179836A - Manufacture of hollow engine valve - Google Patents

Abstract

PURPOSE:To reduce the manufacturing cost by inserting a lubricant covered mandrel into a hollow heat resistant steel blank having a through hole, forming a valve stem and a valve head by hot forming, and removing the mandrel. CONSTITUTION:After a through hole is formed in a column-shaped heat resistant steel billet, the billet is heated and a mandrel 3 covered by a lubricant 4 such as graphite is inserted into the hole. The billet 1 mounted the mandrel 3 is not extruded by a forming die and punch to form a valve steam 8. A billet part 9 to be the valve head is not press upsetted to form a head 12 and the mandrel 3 and the lubricant 4 are cut and removed through a hole 2. Both openings are closed with plugs 14 and 15 by welding to obtain the hollow valve. In this method, the complicated and accurate bore machining is eliminated to reduce the manufacturing cost.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing hollow engine pulp for use in internal combustion engines.

Conventional technology In today's world where high-speed, high-output engines are required, engine pulp not only withstands a high residual atmosphere but also has the advantage of being lightweight and capable of avoiding damage caused by the inertia of the pulp caused by high-speed operation. I'm hoping for something.

As one of the seven measures to reduce weight, attempts have been made to make the pulp slam part thinner than the valve head part, and this has been put into practical use, but due to the strength limitations of the shaft diameter, it is difficult to reduce weight. be.

Another attempt to make the pulp itself hollow is to make it hollow. For example, the 6th O-3
4t7. ! No. 5 specification shoe is made by drilling a hole in the valve material or the valve stem and the preformed product forming the valve stem to make it hollow.
The aluminum alloy core shows engine pulp with a magnesium alloy core loaded and fixed in the resulting hole.

Also, Special Public Sho No. S/-Co91θ6 Specification Sakashio is Special Public Sho No. J
! ;/-29! ;01. The specification states that using a pipe material, inserting an insert to serve as a waste core inside the pipe, or inserting and attaching an insert to serve as a core, and then performing upsetting furnace construction and hot press processing to form a mold. An engine valve is disclosed.

Furthermore, it is also practiced to separately prepare a hollow umbrella part, a stem part, and an @ end part and then layer them. Another attempt to quantify the valve group is to make the pulp itself from a light metal.

However, when attempting to make engine pulp lighter by hollowing it out, there are problems with the process of hollowing out the engine pulp, which requires accurate and precise drilling. Processing is complicated and difficult, as the core insert must be removed by cutting or leaching with starch acid, or each part of the core insert and valve must be welded. There was a point in time when the average price tended to be high. In addition, it is said that manufacturing light alloy engine pulp is not common except for special engines because the material is expensive, processing is difficult, and the surface needs to be hardened through deterioration treatment. The purpose of the present invention is to remove the above-mentioned intermediate points and to
The valve can be manufactured easily and at a similar cost with fewer machining steps, without having to process a precise hole inside the engine valve at a stage close to that of the engine valve, and without having to properly thicken the pipe material at the valve head. The object of the present invention is to provide a V-use method for hollow engine valves that can be used.

The method for producing hollow engine pulp according to the present invention is illumination resistant.
After drilling a hole in the center of the material, heating the material, and inserting a mandrel whose surface is lubricated into the hole; Immediately extrusion molding is performed to form the valve stem part, then hot press molding is performed with the mandrel inserted into the mandrel insertion side of the front material, the umbrella part is upset, and the symandrel is removed by cutting. , the openings of the umbrella portion and the valve stem portion are hermetically sealed.

The present invention will be explained in detail below with reference to the drawings.

EXAMPLE FIG. 1 is a schematic cross-sectional view of an example of the manufacturing process of lightweight engine pulp according to the present invention. Prepare a round-shaped heat-resistant rod material 1, make a hole I in the center, and make it as shown in Fig. 1 (a).
The IT through hole 2 is formed as shown in FIG. Next, this i! l
! +#I#l The rod material is heated and the mandrel 8 is inserted into the hole 2 of the material 1 as shown in FIG. 1(b). As shown in Figure 2, the mandrel has a lubricant 4 made of heat-resistant material such as medium and 11, graphite, and a flange 5 on the shaft end to prevent it from falling. is provided. The mandrel B itself requires a certain strength and hardness because it is affected by heat, and is made of high carbon or alloy steel.

Next, as shown in FIG. 1 (cl), the material 1 covered with a mandrel is inserted into the extrusion molding goo 6 shown in FIG. is added and subjected to forward extrusion for a period of pA to form the pulp stem 8, and the material portion 9 that is to become the valve head is left behind in the gou.During this extrusion, the entire mandrel enters into the material 1, Although the collar 5 of the mandrel is flush with the end face of the portion 9, slippage is ensured between the extruded portion of the material and the mandrel due to the #l! slipping material 4, and movement of the mandrel is prevented.

Next, as shown in Fig. 1 (di), insert the extruded material 1 into the die IOK as shown in Fig. d, and press the pinch 1
In step 1, the umbrella portion 12 having a predetermined shape is formed on the portion 9 by hot press upsetting. Hot extrusion and track pressing must be carried out quickly so that the insertion mandrel does not lose its strength due to heat.

Next, the mandrel 8 and the lubricant 4 are removed by cutting from the opening of the hole 2 in the valve head portion 12. Therefore, the engine valve is a hollow structure with an opening outside the plane.

After I#, if necessary, load an IJum into the space 18 of the engine valve to increase the cooling effect, seal the opening of the valve head with the plug 14, and close the opening of the valve stem with a 14t. ! The end portion 15 is welded tightly. As a method of sealing the opening of the valve stem portion, as shown in FIG. 3, the space 18 may be sealed off by drawing an oval on the end portion.

As is clear from the gauze that is more effective, according to the present invention, ■ A hollow material with trace holes is produced monthly, and after inserting a mandrel surrounded by a lubricant into it, a hole is placed in front of the gauge on the side opposite to the insertion side of the mandrel. The stem part was formed by extrusion, the valve head part was formed by hot pressing on the mandrel insertion, and then the mandrel was added or removed to manufacture the hollow engine valve. , a hollow engine valve can be manufactured simply and at low cost with fewer machining steps without involving complicated machining such as precisely drilling holes in the engine valve.

FIG. 2 is a cross-sectional view showing an example of a mandrel used for preparing the engine pulp of the present invention; FIG. FIG. 4 is a schematic diagram showing the die and dench for the #7 mold used for the hot press forming of the middle engine pulp according to the present invention. Fig. 3 is a partially cutaway sectional view showing a hollow engine pulp according to another example of the method for producing engine pulp according to the present invention.

2...hole 8... Mandrel 4...Lubricant 8...Pulp stem part 12...Pulp umbrella part 18... Space Figure 1 Figure 4 1st floor Figure 5

Claims (1)

[Claims] 1. When manufacturing a hollow engine valve, a hole is made in the center of a material made of heat-resistant steel, the material is heated, and a mandrel whose surface is coated with a lubricant is inserted into the hole.
Immediately hot extrusion molding is performed on the end portion of the material opposite to the side where the mandrel is inserted to form a valve stem portion, and then hot press molding is performed with the mandrel inserted on the mandrel insertion side of the material. 1. A method for manufacturing a hollow engine valve, which comprises the steps of: removing the mandrel by cutting after upsetting the umbrella portion by applying a heat treatment, and sealing the openings of the umbrella portion and the valve stem portion.