Broach Cutter Grinding with Rake Angle Control

Patent metadata

Field	Value
Publication number	US-2025319565-A1
Application number	US-202519177975-A
Country	US
Kind code	A1
Filing date	Apr 14, 2025
Priority date	Apr 12, 2024
Publication date	Oct 16, 2025
Grant date	—

Abstract

A broach or broach segment has a spine. A longitudinal array of teeth protrude from the spine, each tooth having: a first face and an opposite second face; and a distal surface joining the first face and second face; and at least some of the teeth being firtree teeth and have a peripheral trench adjacent the cutting edge of the at least one tooth.

First claim

What is claimed is:

1 . A method for grinding a disk slot broach or broach segment, the broach or broach segment comprising:
a spine; and a longitudinal array of teeth protruding from the spine, each said tooth having:
a first face and an opposite second face; and
a distal surface joining the first face and second face,

the method comprising grinding the first face of each tooth of a plurality of said teeth with a lateral surface of a rotating quill driven for rotation about a quill axis.

2 . The method of claim 1 wherein the grinding comprises:
a continuous reorientation of the quill.

3 . The method of claim 1 wherein the grinding comprises:
reorienting the quill to provide a desired rake angle.

4 . The method of claim 1 wherein:
the grinding with the lateral surface of a rotating quill follows grinding with a face of a grinding wheel to form a peripheral trough in a face left by said grinding wheel.

5 . The method of claim 1 the grinding comprises:
reorienting the quill to provide a rake angle of 7.5° to 8.5° over a majority of a cutting edge of at least one tooth.

6 . The method of claim 5 wherein the reorienting provides:
said rake angle of 6.0° to 10.0° over said majority of said cutting edge of a plurality of the teeth.

7 . The method of claim 5 wherein the reorienting provides at least one of:
said rake angle of 6.0° to 10.0° over at least 70% of said cutting edge of at least 25% of all teeth;
said rake angle of 6.0° to 10.0° over said majority of said cutting edge of at least 25% of each tooth of a trailing 10% of teeth; and
said rake angle of 6.0° to 10.0° over at least 70% of said cutting edge of at least 25% of each tooth of trailing 10% teeth.

8 . The method of claim 1 wherein:
the grinding forms a peripheral trench adjacent the cutting edge of at least one tooth.

9 . The method of claim 8 wherein:
the trench is segmented.

10 . The method of claim 8 wherein:
the trench extends along one or more flat facets.

11 . The method of claim 1 wherein:
the grinding is a regrind and forms a rake angle varying relative to aa surface inboard thereof.

12 . The method of claim 1 wherein:
a cylindrical lateral surface of the quill forms a straight section outer terminal portion of the trench; and
a domed end of the quill forms a concave inboard terminal boundary/wall of the trench for deflecting curling chips.

13 . A broach or broach segment comprising:
a spine; and a longitudinal array of teeth protruding from the spine, each said tooth having:
a first face and an opposite second face; and
a distal surface joining the first face and second face; and
at least some of the teeth being firtree teeth; and a rake angle varying by no more than +/−0.5° over a majority of a cutting edge of at least one tooth.

14 . The broach or broach segment of claim 13 wherein:
the firtree teeth have a plurality of lobes protruding on both sides of a centerplane and progressively increasing in transverse dimension toward a distal edge of the broach, optionally, there being 3 to 6 such lobes; and
the rake angle is of 7.5° to 8.5° over a majority of a cutting edge of at 25% of the teeth of the broach or broach segment and/or the rake angle of 7.5° to 8.5° is over a majority of a cutting edge of at 25% of the trailing 10% of teeth of the broach.

15 . The broach or broach segment of claim 13 further comprising:
a peripheral trench adjacent the cutting edge of the at least one tooth.

16 . The broach or broach segment of claim 13 wherein:
the peripheral trench recesses the cutting edge by a distance S E from the continuation/projection of the first face;
the peripheral trench has a maximum depth S D at least 110% of the recess distance S E ; and
the peripheral trench has a concave inner boundary at a terminal angle θ C of 55° to 80° off parallel to said projection.

17 . The broach or broach segment of claim 13 wherein:
the peripheral trench is in at least one flat facet.

18 . A broach or broach segment comprising:
a spine having a longitudinal centerplane; a longitudinal array of teeth protruding from the spine, each said tooth having:
a first face and an opposite second face; and
a distal surface joining the first face and second face; and
at least some of the teeth being firtree teeth and having a peripheral trench adjacent the cutting edge thereof.

19 . The broach or broach segment of claim 18 wherein:
the peripheral trench recesses the cutting edge by a distance S E from the continuation/projection of the first face;
the peripheral trench has a maximum depth S D at least 110% of the recess depth S E ; and
the peripheral trench has a concave inner boundary at a terminal angle θ C of 55° to 80° off parallel to said projection.

20 . The broach or broach segment of claim 18 wherein:
the peripheral trench is continuous along at least two lobes on each side of at least one tooth.

Assignees

• Rtx Corp

Inventors

• Guo Changsheng
• Ranganath Santosh K
• Kountanya Raja K

Classifications

• B23D2043/025

  for producing grooves in turbines, e.g. for the insertion of blades · CPC title

• B23D43/02

  for cutting by rectilinear movement (B23D43/08 takes precedence) · CPC title

• B23D37/22

  for special purposes (B23D37/14 takes precedence) · CPC title

• B23D37/12

  for broaching outer surfaces · CPC title

• B24B3/16 Primary

  of broaches · CPC title