U.S. patent application number 09/949751 was filed with the patent office on 2003-03-13 for gear cutter blade.
Invention is credited to Bradfield, Joseph, Sullivan, Robert.
Application Number | 20030049084 09/949751 |
Document ID | / |
Family ID | 25489507 |
Filed Date | 2003-03-13 |
United States Patent
Application |
20030049084 |
Kind Code |
A1 |
Bradfield, Joseph ; et
al. |
March 13, 2003 |
GEAR CUTTER BLADE
Abstract
A cutter blade for use with a face hob type cutter for producing
the teeth of spiral bevel and hypoid gear members by a continuous
index, face hobbing process comprises a cutter blade shank having a
cutting member provided at one end thereof. The cutting member
includes a tooth side cutting edge having a given axial pressure
angle, and a tooth topland cutting edge. The tooth topland cutting
edge of the cutting member simultaneously forms a topland surface
of the tooth of the gear member as the tooth is cut by the tooth
side cutting edge of the cutting member.
Inventors: |
Bradfield, Joseph; (Columbia
City, IN) ; Sullivan, Robert; (Fort Wayne,
IN) |
Correspondence
Address: |
Liniak, Berenato, Longacre & White
Ste. 240
6550 Rock Spring drive
Bethesda
MD
20817
US
|
Family ID: |
25489507 |
Appl. No.: |
09/949751 |
Filed: |
September 12, 2001 |
Current U.S.
Class: |
409/12 ; 407/20;
409/26; 409/51 |
Current CPC
Class: |
Y10T 407/171 20150115;
B23F 21/236 20130101; Y10T 407/17 20150115; Y10T 409/101749
20150115; Y10T 407/1705 20150115; Y10T 409/103975 20150115; Y10T
409/10795 20150115 |
Class at
Publication: |
409/12 ; 409/26;
409/51; 407/20 |
International
Class: |
B23F 005/00; B26D
001/12 |
Claims
What is claimed is:
1. In combination with a gear member having a plurality of gear
teeth each having a pair of opposite side surfaces and a topland
surface, a gear cutter blade for producing said gear member with
uniform depth teeth, said gear cutter blade comprising: a shank;
and a cutting member formed at a distal end of said shank; said
cutting member having a cutting edge including a first section
extending from said distal end of said shank at a given axial
pressure angle and dimensioned to cut at least one of said side
surfaces of said gear tooth of said gear member, and a second
section substantially perpendicular to a central axis of said
cutter blade and dimensioned to cut at least a substantial portion
of said topland surface of said gear tooth.
2. The combination as defined in claim 1, wherein said second
section of said cutting edge is substantially straight.
3. The combination as defined in claim 1, wherein an axial distance
from a tip of said cutting member to an intersection of said first
section of said cutting edge and said second section of said
cutting edge is substantially equal to the whole depth of said gear
teeth.
4. The combination as defined in claim 1, wherein said second
section is provided for cutting said entire topland surface of said
gear tooth.
5. In combination with a gear member having a plurality of gear
teeth each having a pair of opposite side surfaces and a topland
surface, a gear cutter blade for a face hob type cutting apparatus
for producing said gear member with uniform depth teeth by a
continuous face hobbing process, said gear cutter blade comprising:
a shank; a central axis; and a cutting member formed at a distal
end of said shank; said cutting member having a tip and a cutting
edge including a first section dimensioned to cut at least one of
said side surfaces of said gear tooth, and a second section
adjacent to said first section and dimensioned to cut at least a
substantial portion of a topland surface of said gear tooth; said
first section of said cutting edge extends from said distal end of
said shank at a given axial pressure angle; said second section of
said cutting edge is substantially straight and extends
substantially perpendicularly to said central axis of said cutter
blade; wherein an axial distance from said tip of said cutting
member to an intersection of said first section of said cutting
edge and said second section of said cutting edge is substantially
equal to the whole depth of said gear teeth.
6. A method for producing a gear member by a continuous index, face
hobbing process, said gear member having a plurality of teeth each
having opposite side surfaces and a topland surface, said method
comprising the steps of: rotating a circular face hob type cutter
head carrying a plurality of gear cutter blades; rotating said gear
member in a timed relationship with said cutter head; and providing
a relative feed motion of said cutter head and said gear member so
that successive gear cutter blades engage successive tooth slots as
said gear member is being cut, wherein each of said gear cutter
blades includes a cutting member having a cutting edge including a
first section extending from said distal end of said shank at a
given axial pressure angle and dimensioned to cut at least one of
said side surfaces of said gear tooth of said gear member, and a
second section substantially perpendicular to a central axis of
said cutter blade and dimensioned to cut at least a substantial
portion of said topland surface of said gear tooth so that said
second section simultaneously forms at least a substantial portion
of said topland surface of said tooth of said gear member as said
tooth is cut by said first section of said cutting edge of said
cutting member.
7. The method for producing a gear member as defined in claim 6,
wherein said topland surface is formed substantially straight.
8. The method for producing a gear member as defined in claim 6,
wherein said second section is provided for cutting said entire
topland surface of said gear tooth.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to cutter blades for the production of
gears and, more particularly, to cutter blades for the face hobbing
of parallel depth spiral bevel and hypoid gears.
[0003] 2. Description of the Prior Art
[0004] Spiral bevel and hypoid gear pairs are conventionally
produced utilizing either an intermittent index face milling method
or a continuous indexing face hobbing method. While most gear set
manufacturers currently use the face milling method, the face
hobbing process has been recently adopted by some manufacturers,
especially those manufacturing such gear sets for vehicular
applications. In a face hobbing machine, a circular face hob type
rotary cutter carrying a plurality of cutter blades mounted in
groups, is utilized, and a workpiece (gear blank) and the cutter
continuously rotate in a timed relationship until the entire part
is completed. During the cutting process, the workpiece indexes in
a rotary manner so that each successive cutter blade groups
engaging successive tooth slots as the gear or pinion member is
being cut. Advantageously, the face hobbing method produces uniform
depth teeth, and parts are produced from the solid in one
operation. The face hobbing method also requires fewer production
steps and less production time than the face milling method.
[0005] Normally, in an operation separate from, and preceding to,
the tooth cutting operation, a topland surface of the gear is
machined while processing a ring gear or pinion gear blank before
cutting the gear teeth. As well known to those skilled in the art,
the additional production step is generally disadvantageous with
regard to cost, labor, quality control, and manufacturing
flexibility.
SUMMARY OF THE INVENTION
[0006] The present invention relates to a gear cutter blade for use
with a face hob type cutter for producing teeth of spiral bevel and
hypoid gear members by a continuous index, face hobbing process.
The gear cutter blade comprises a cutter blade shank adapted to be
mounted on a rotatable cutter body, and a cutting member provided
at one end of the blade shank. The cutting member includes a tooth
side cutting edge having a given axial pressure angle, and a
topland cutting edge adjacent the tooth side cutting edge. The
topland cutting edge of the cutting member simultaneously forms a
topland surface of the tooth of the gear member as a tooth side
surface is cut by the tooth side cutting edge of the cutting
member.
[0007] Machining the topland surface simultaneously with the
cutting the tooth side surface permits to reduce or completely
eliminate the need to finish topland surfaces of the ring gears or
pinions. Moreover, the elimination of a subsequent manufacturing
operation improves the consistency and accuracy of the gear tooth
whole depth, and part quality, as well as reduces manufacturing
costs. In addition, the gear cutter blade of the present invention
allows for greater manufacturing flexibility, as the cutting edge
dimensions can be easily modified, and provides an ability to
machine near-net forged parts without requiring precision control
of the topland area of machining with an interrupted cut during a
blanking operation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Other objects and advantages of the invention will become
apparent from a study of the following specification when viewed in
light of the accompanying drawings, wherein:
[0009] FIG. 1 is a plan view of a front face of a gear cutter blade
in accordance with the preferred embodiment of the present
invention and a portion of a gear member on which the cutter blade
is operating;
[0010] FIG. 2 is a partial perspective view of a ring gear;
[0011] FIG. 3 is a view of the cutter blade of FIG. 1 illustrating
geometry of a cutting edge thereof in accordance with the present
invention;
[0012] FIG. 4 illustrates the arrangement of a workpiece (a ring
gear) and a cutter in a face hobbing process used in the present
invention;
[0013] FIG. 5 is a plan view of the front face of the gear cutter
blade in accordance with the alternative embodiment of the present
invention dimensioned to cut an entire topland surface of a gear
tooth of the gear member.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0014] The preferred embodiment of the present invention will now
be described with the reference to accompanying drawings.
[0015] Referring to FIGS. 1 and 3, the reference numeral 10
represents a gear-cutting blade in accordance with the present
invention and the reference numeral 12 depicts a portion of a ring
gear member 12 having a plurality of gear teeth 14 on which the
gear cutting blade 10 is operating during a face hobbing process.
Each gear tooth 14 includes opposite side surfaces 16 and a topland
surface 18. The reference numeral A represents a whole depth of the
gear teeth 14. The gear member 12 is also illustrated separately in
detail in FIG. 2.
[0016] A plurality of the cutter blades 10 is mounted at a selected
radius and depth on a rotatable, circular cutter head 2 of a gear
cutter assembly 1 as part of a face hobbing cutter system, as
illustrated in FIG. 4. Examples of such systems include
Tri-Ac.RTM., Pentac.RTM., and Spiron.RTM.. During a face hobbing
process, the gear member 12 (workpiece), mounted to a workpiece
holder (not shown), and the cutter head 2 continuously rotate, with
successive cutter blades 10 engaging successive tooth slots as the
gear member 12 being cut. FIG. 4 also shows the face hobbing
process and the relative interaction of the gear member 12
(workpiece), in this case the ring gear, as the gear teeth 14 are
successfully cut by the cutter blades 10 mounted on the cutter head
2. The gear member 12 and the cutter head 2 each rotate in the
direction of the arrows indicated.
[0017] The cutter blades 10 are generally mounted on the cutter
head 2 of the gear cutter assembly in groups. For instance, in the
systems offered by The Gleason Works, the cutter blades are
arranged on the cutter head in groups of two, each cutter blade
pair operating on a different tooth space. In other systems, the
cutter blades may be arranged on the cutter head in groups of
three. In such systems, there is an inner, outer and rougher blade,
which operate to cut the sides and bottom of each tooth space,
respectively. The rougher cutter blade is generally provided with
both inner and outer cutting edges. The cutter blade 10 illustrated
in the drawings is one of the side cutting blades suitable for use
with either a two blade or a three blade group.
[0018] While the ring gear member 12 is illustrated in FIGS. 1 and
2, the gear cutter blade of the present invention is equally
applicable to the face hobbing of the pinion member of a gear
set.
[0019] The face hobbing cutting systems generally utilize cutter
blades, which are profile ground at the end user's facility from
uniform blanks to afford a variety of specified configurations. As
illustrated in FIGS. 1 and 3, the cutter blade 10 includes a shank
20 and a cutting member 22 formed at a distal end 21 thereof. A
front face of the cutting member 22 of each cutter blade 10 is
provided, generally only on one side thereof, with a cutting edge
24. The cutting edge 24 comprises a first section 26 for cutting
the side surface 16 of the gear teeth 14, and a second section 28
for cutting the top surface 18 of the gear teeth 14. Thus, the
first section 26 defines a tooth side cutting edge and the second
section 28 defines a tooth topland cutting edge.
[0020] The first section 26 of the cutting edge 24 extends from a
tip 30 of the cutting member 22 at a predetermined axial pressure
angle B. The axial pressure angle B of the first section 26 of the
cutting edge 24 obviously depends on the angle desired for the
sides of the gear teeth. As used herein, "axial pressure angle" is
defined as the angle between the first section 26 of the cutting
edge 24 (or tooth profile) and a central axis 11 of the cutter
blade 10.
[0021] The second section 28 of the cutting edge 24 is a
substantially straight line perpendicular to the central axis 11 of
the cutter blade 10, and is characterized by a width W, as
illustrated in FIG. 3.
[0022] A distance C from the tip 30 of the cutting member 22 to an
intersection of the first section 26 and the second section 28 of
the cutting edge 24 is a height of the first section 26 of the
cutting edge 24 of the cutting member 22. The distance C is
substantially equal to the whole depth A of the gear teeth 14.
[0023] By modifying the specified blade grinding parameters for
forming the cutter blade 10 from a blank, configuration of the
cutting edge 24 can be altered to incorporate the second section
28.
[0024] Thus, the gear cutter blade 10 of the present invention cuts
the side surface 16 of the gear tooth 14 by means of the first
section 26 of the cutting edge 24, and simultaneously forms a
substantial portion of the topland surface 18 of the gear tooth 14
by means of the second section 28 of the cutting edge 24.
Alternatively, the second section 28 of the cutting edge 24 is
dimensioned to cut an entire topland surface 18 of the gear tooth
14, as illustrated in FIG. 6.
[0025] The cutter blades 10 of the present invention are secured to
the circular cutter head 2 in the conventional manner, and the face
hobbing system is operated in the same manner as if conventional
cutter blades were employed. However, during a face hobbing process
of the present invention, as cutter head 2 continuously rotates,
the successive cutter blades 10 cut the side surfaces 16 of the
gear teeth 14 by means of the first section 26 of the cutting edge
24, and simultaneously machines at least a substantial portion of
the topland surface 18 of the gear tooth 14 by means of the second
section 28 of the cutting edge 24.
[0026] Therefore, with the gear cutter blade 10 of the present
invention, the topland surface is machined on the teeth of a gear
or pinion member simultaneously with the tooth side cutting
operation. This permits to reduce or completely eliminate the need
to finish topland surfaces of the ring gears or pinions. Moreover,
the elimination of a subsequent manufacturing operation improves
the consistency and accuracy of the gear tooth whole depth, and
part quality, as well as reduces manufacturing costs. In addition,
the gear cutter blade of the present invention allows for greater
manufacturing flexibility, as the cutting edge dimensions can be
easily modified, and provides an ability to machine near-net forged
parts without requiring precision control of the topland area of
machining with an interrupted cut during a blanking operation.
[0027] As an example of a working embodiment of the gear cutter
blade of the present invention, gear cutting tools having the
following characteristics have been designed:
[0028] Material: High Speed Steel or Carbide;
[0029] Axial Pressure Angle B: 5.degree. to 35.degree.;
[0030] Distance C: 0.150" to over 1.000";
[0031] Width W: 0.030" to 0.200".
[0032] The foregoing description of the preferred embodiments of
the present invention has been presented for the purpose of
illustration in accordance with the provisions of the Patent
Statutes. It is not intended to be exhaustive or to limit the
invention to the precise forms disclosed. Obvious modifications or
variations are possible in light of the above teachings. The
embodiments disclosed hereinabove were chosen in order to best
illustrate the principles of the present invention and its
practical application to thereby enable those of ordinary skill in
the art to best utilize the invention in various embodiments and
with various modifications as are suited to the particular use
contemplated, as long as the principles described herein are
followed. Thus, changes can be made in the above-described
invention without departing from the intent and scope thereof. It
is also intended that the scope of the present invention be defined
by the claims appended thereto.
* * * * *