Method of manufacturing a hollow poppet valve

Patent metadata

Field	Value
Publication number	US-9751164-B2
Application number	US-201315035955-A
Country	US
Kind code	B2
Filing date	Nov 21, 2013
Priority date	Nov 21, 2013
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A hollow poppet valve has an internal cavity which extends from within its valve head into a valve stem portion and is partly filled with a coolant. A manufacturing method includes forming a coolant rod by cutting clayish coolant to a coolant rod of a predetermined length from the coolant material extruded from an extruder; a coolant-rod insertion step in which a coolant rod is inserted into a cavity formed in an intermediate valve product through its opening; and a step of sealing the opening of the hole. In the coolant-rod insertion step, coolant-rods are inserted into the cavity separately in multiple times. Since each coolant rod is short, it is little deformed or bent, so that it has little interference with the inner periphery of the cavity, which permits use of a thick rod and increase the amount of the coolant in the cavity.

First claim

The invention claimed is:

1. A method of manufacturing a hollow poppet valve having an internal cavity that extends from within a valve head into a stem portion of the hollow poppet valve and is filled with a coolant, the method comprising:
a coolant-rod forming step including extruding a linear clayish coolant from a nozzle of an extruder and cutting the linear coolant into coolant rods of a predetermined length;
a plurality of coolant-rod inserting steps each including inserting the coolant rod into a hole of an intermediate valve product that corresponds to the internal cavity of the hollow poppet valve, through an open end of the hole, such that more than one coolant rod is inserted into the hole of the intermediate valve product;
a coolant-rod pressurizing step including pressurizing each of the coolant rods in the hole with a pressing rod, thereby plastically deforming the coolant rods, following insertion of each coolant rod; and
a sealing step for sealing the open end of the hole.

2. The method according to claim 1 ,
wherein, in the plurality of coolant-rod insertion steps, the coolant rods are inserted into the hole of the intermediate valve product via an opening of a valve head cavity formed in a bottom of the valve head of the intermediate valve product, the valve head cavity communicating with a stem cavity, the stem cavity being diametrically smaller than the valve head cavity; and
wherein, in the sealing step, a cap is welded to the opening of the valve head cavity.

3. The method according to claim 2 , wherein the plurality of coolant-rod insertion steps includes a first coolant-rod insertion inserting a coolant rod having a diametrically small thickness that corresponds to the stem cavity and a second coolant-rod insertion inserting a coolant rod having a diametrically large thickness that corresponds to the valve head cavity.

4. The method according to claim 1 , wherein the coolant-rod pressurizing step includes determining existence of the coolant rods in the hole and propriety in length of the coolant rods on the basis of a length of the pressing rod inserted into the hole.

5. The method according to claim 1 , wherein the coolant-rod forming step includes
causing the linear coolant extruded from the nozzle of the extruder to be inserted into a circular cylindrical jig disposed in opposition to a lower open end of the nozzle;
stopping extrusion of the linear coolant from the nozzle when a predetermined amount of coolant rod is extruded from the nozzle; and
cutting the linear coolant to the coolant rod of a predetermined length with a cutter provided in the neighborhood of the nozzle, and storing the cut coolant rod in the jig,
wherein the coolant rod in the jig is arranged above, and in opposition to, an upper open end of the hole of the intermediate valve product and is ejected into the hole of the intermediate valve product by a pressure of a gas acting on a rear end of the coolant rod, by bringing a downward opening of a cup shape guide portion provided on a lower end of the jig into engagement with an upper end of the intermediate valve product, and
wherein the pressurized gas in the hole of the intermediate valve product is discharged from the hole through a groove formed in an inner surface of a recess of the cup shape guide portion in contact with an upper end of the intermediate valve product.

6. The method according to claim 1 ,
wherein each of the plurality of coolant-rod insertion steps includes inserting a coolant rod into the hole of the intermediate valve product via an opening of a stem cavity formed at one end of a stem of the intermediate valve product, the stem cavity communicating with the valve head cavity, the stem cavity being diametrically smaller than the valve head cavity; and
wherein the sealing step includes joining a stem end member to an open end of the stem of the intermediate valve product.

Assignees

• Nittan Valva

Inventors

• Ishii Kazuhiro
• Uchida Shigeru
• Meguro Masahiro

Classifications

• B21K1/22

  poppet valves, e.g. for internal-combustion engines · CPC title

• B23P15/002 Primary

  poppet valves · CPC title

• F01L3/14 Primary

  by means of a liquid or solid coolant, e.g. sodium, in a closed chamber in a valve · CPC title

• F01L3/08

  Valves guides; Sealing of valve stem, e.g. sealing by lubricant · CPC title

• Y10T29/49298

  Poppet or I.C. engine valve or valve seat making · CPC title