Methods of manufacturing part with hole having cut threads

Patent metadata

Field	Value
Publication number	US-11577331-B2
Application number	US-202017134986-A
Country	US
Kind code	B2
Filing date	Dec 28, 2020
Priority date	Dec 28, 2020
Publication date	Feb 14, 2023
Grant date	Feb 14, 2023

Abstract

A method of manufacturing a threaded hole in a workpiece includes providing the workpiece having a region with a hole. The method also includes cutting a threading for the hole. Furthermore, the method includes, independent of cutting the threading, densifying the region proximate the hole to reduce material porosity in the region.

First claim

What is claimed is:

1. A method of manufacturing an engine block with a threaded hole from a workpiece comprising:
providing the workpiece having a region with a hole, the region having a cross sectional thickness proximate the hole, the cross sectional thickness measured along a length of the hole;
inserting and advancing a tapered end of a rod into the hole to expand the hole and densifying a region proximate the hole to reduce a material porosity in the region and to create a densified region proximate the hole without significantly changing the cross sectional thickness; and
cutting a threading for the hole into the densified region.

2. The method of claim 1 , wherein densifying the region includes radially expanding the hole before cutting the threading for the hole.

3. The method of claim 2 , wherein cutting the threading includes providing a plurality of cut threads at a minor diameter;
wherein radially expanding the hole includes expanding the hole from a first hole diameter to a second hole diameter; and
wherein the second diameter dimension is approximately equal to the minor diameter.

4. The method of claim 2 , wherein cutting the threading includes providing a plurality of cut threads at a minor diameter;
wherein radially expanding the hole includes expanding the hole from a first hole diameter to a second hole diameter; and
further comprising selecting the second diameter according to the minor diameter.

5. The method of claim 2 , wherein the cutting the threading includes providing a plurality of cut threads at a major diameter; and
wherein radially expanding the hole includes densifying the region within a zone radiating outward from the hole to an outer radial dimension that is, at least, equal to the major diameter.

6. The method of claim 2 , wherein radially expanding the hole includes radially expanding the hole via cold working.

7. A method of manufacturing a threaded hole in a main bearing bolt hole of an engine block comprising:
providing the engine block having a region with a hole, the hole having a smooth inner diameter surface, the region having a cross sectional thickness proximate the hole, the cross sectional thickness measured along a length of the hole;
inserting and advancing a tapered end of a rod into the hole to expand the hole, create a densified region proximate the hole, and to reduce material porosity in the region without significantly changing the cross sectional thickness; and
after inserting and advancing the tapered end into the hole to expand the hole, cutting a threading for the hole into the densified region.

8. The method of claim 7 , further comprising creating the densified region by radially expanding the hole before cutting the threading for the hole.

9. The method of claim 8 , wherein cutting the threading includes providing a plurality of cut threads at a minor diameter;
wherein radially expanding the hole includes expanding the hole from a first hole diameter to a second hole diameter; and
wherein the second diameter dimension is approximately equal to the minor diameter.

10. The method of claim 8 , wherein cutting the threading includes providing a plurality of cut threads at a minor diameter;
wherein radially expanding the hole includes expanding the hole from a first hole diameter to a second hole diameter; and
further comprising selecting the second diameter according to the minor diameter.

11. The method of claim 8 , wherein the cutting the threading includes providing a plurality of cut threads at a major diameter; and
wherein radially expanding the hole includes densifying the region within a zone radiating outward from the hole to an outer radial dimension that is, at least, equal to the major diameter.

12. The method of claim 8 , wherein radially expanding the hole includes radially expanding the hole via cold working.

13. A method of manufacturing a threaded hole of an engine block comprising:
providing the engine block having a region with a hole, the hole having a smooth inner diameter surface, the region having a cross sectional thickness proximate the hole that is constant, the cross sectional thickness measured along a length of the hole;
inserting and advancing a tapered end of a rod into the hole to expand the hole, create a densified region proximate the hole, and to reduce material porosity in the region without significantly changing the cross sectional thickness; and
after inserting and advancing the tapered end into the hole to expand the hole, cutting a threading for the hole into the densified region.

14. The method of claim 13 , further comprising creating the densified region by radially expanding the hole before cutting the threading for the hole.

15. The method of claim 14 , wherein cutting the threading includes providing a plurality of cut threads at a minor diameter;
wherein radially expanding the hole includes expanding the hole from a first hole diameter to a second hole diameter; and
wherein the second diameter dimension is approximately equal to the minor diameter.

16. The method of claim 14 , wherein cutting the threading includes providing a plurality of cut threads at a minor diameter;
wherein radially expanding the hole includes expanding the hole from a first hole diameter to a second hole diameter; and
further comprising selecting the second diameter according to the minor diameter.

17. The method of claim 14 , wherein the cutting the threading includes providing a plurality of cut threads at a major diameter; and
wherein radially expanding the hole includes densifying the region within a zone radiating outward from the hole to an outer radial dimension that is, at least, equal to the major diameter.

18. The method of claim 14 , wherein radially expanding the hole includes radially expanding the hole via cold working.

19. The method of claim 14 , wherein the rod includes the tapered end and a finishing portion with a constant diameter;
wherein radially expanding the hole includes expanding the hole from a first hole diameter to a second hole diameter; and
wherein the constant diameter is approximately equal to the second hole diameter.

20. The method of claim 13 , wherein providing the engine block having the region with the hole includes casting the hole into the region.

Assignees

• Gm Global Tech Operations Llc
• Gm Global Tech Operatins Llc

Inventors

• Choudhary Lokesh
• Wang Qigui
• Munikamal Tiruttani
• Wulbrecht David A
• Melekian Gregory
• Sachdev Anil K

Classifications

• B23G1/18

  Machines with one working spindle · CPC title

• B23G1/00 Primary

  Thread cutting; Automatic machines specially designed therefor · CPC title

• B23G2200/14

  Multifunctional threading tools · CPC title

• B23P15/00

  Making specific metal objects by operations not covered by a single other subclass or a group in this subclass · CPC title

• B23G2240/36

  Methods of threading not otherwise provided for · CPC title