U.S. patent application number 09/750981 was filed with the patent office on 2002-05-30 for rolling machine capable of forming different types of teeth simultaneously.
Invention is credited to Lee, Eun-taek, Lee, Jung-il.
Application Number | 20020062671 09/750981 |
Document ID | / |
Family ID | 19701111 |
Filed Date | 2002-05-30 |
United States Patent
Application |
20020062671 |
Kind Code |
A1 |
Lee, Jung-il ; et
al. |
May 30, 2002 |
Rolling machine capable of forming different types of teeth
simultaneously
Abstract
A rolling machine for performing a rolling of different types of
teeth mounted on a shaft, is provided with a forming die including
a first section and a second section provided with a camming
profiled circumferential surface of 360 degree. The circumferential
surface is divided into a guide surface of a predetermined angle, a
gradual forming surface of a predetermined angle, a finishing
section surface of a predetermined angle, and a rotation stop
section surface of a predetermined angle, which are angularly
positioned in that order on the circumferential surface. The
rolling machine is also provided with a power transmitting device
for transmitting and disconnecting a driving force to the forming
die and a position detecting sensor for controlling a stop timing
of the forming die.
Inventors: |
Lee, Jung-il;
(Pyoungtaek-city, KR) ; Lee, Eun-taek;
(Daejeon-city, KR) |
Correspondence
Address: |
Cooper & Dunham LLP
1185 Avenue of the Americas
New York
NY
10036
US
|
Family ID: |
19701111 |
Appl. No.: |
09/750981 |
Filed: |
December 28, 2000 |
Current U.S.
Class: |
72/108 |
Current CPC
Class: |
B21H 5/02 20130101 |
Class at
Publication: |
72/108 |
International
Class: |
B21D 015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 24, 2000 |
KR |
2000-70232 |
Claims
What is claimed is:
1. A rolling machine for performing a rolling of different types of
teeth mounted on a shaft, the machine comprising: a forming die
including a first section and a second section provided with a
camming profiled circumferential surface of 360 degree, the
circumferential surface being divided into a guide surface of a
predetermined angle, a gradual forming surface of a predetermined
angle, a finishing section surface of a predetermined angle, and a
rotation stop section surface of a predetermined angle, which are
angularly positioned in that order on the circumferential surface;
a power transmitting device for transmitting and disconnecting a
driving force to the forming die; and a position detecting sensor
for controlling a stop timing of the forming die.
2. The rolling machine of claims 1, wherein the guide surface has a
same curvature and ranges from 80 degree to 100 degree in the
circumferential surface of 360 degree.
3. The rolling machine of claims 1, wherein the gradual forming
surface has a crest of the tooth which has its height higher along
the circumference from an initial point toward a completion
point.
4. The rolling machine of claims 1, wherein the gradual forming
surface ranges from 125 degree to 145 degree in the circumferential
surface of 360 degree.
5. The rolling machine of claims 1, wherein the gradual forming
surface is eccentrically formed to have a radius from a central
axis which becomes larger in 0.02 mm increment from tooth to
tooth.
6. The rolling machine of claims 1, wherein the tooth profile of
the finishing section surface is same as that of a completion point
of the gradual forming surface.
7. The rolling machine of claims 1, wherein the finishing section
surface has a range from 80 degree to 100 degree in the
circumferential surface of 360 degree.
8. The rolling machine of claims 1, wherein the rotation stop
section surface is formed between an angular range about 35 to 55
degree in the circumferential surface of 360 degree.
9. The rolling machine of claims 1, wherein the rotation stop
section surface does not have a tooth for performing the rolling of
the tooth.
10. The rolling machine of claims 1, wherein the power transmitting
device includes a driving motor for generating the driving force, a
driving shaft receiving the driving force from the driving motor, a
clutch for connecting and disconnecting the driving force from the
driving shaft, and a brake for stopping the rotation of the driving
shaft.
11. The rolling machine of claims 1, wherein the position detecting
sensor includes a driving force disconnecting sensor positioned at
the initial point of the rotation stop section surface, and a stop
check sensor positioned at a center portion of the rotation stop
section surface.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a rolling machine; and,
more particularly, to a rolling machine capable of forming
different types of teeth which are coaxially formed with each
other, at the same time.
DESCRIPTION OF THE PRIOR ART
[0002] In general, a rolling is widely used to form, e.g., a thread
by interposing a thread blank or thread base metal between two or
more sets of forming dies to be rolled therebetween. The metal
plasticity of the thread blank enables the rolling. Since the
rolling enables to product the thread having a higher accuracy and
uniformity, manufacturing the normal thread is mainly achieved
through the rolling.
[0003] There are many types of thread rolling apparatuses or
rolling machines. The types of thread rolling apparatuses to be
used is determined depending on the property of the component and
an amount of production.
[0004] The thread rolling is largely divided into three kinds of
methods.
[0005] First is to use flat dies or rack dies. A set of dies are
arranged with the metal blank being supported therebetween and,
then each of the dies is moved in an opposite direction to form the
thread.
[0006] Secondly, a rotational method is performed in such a manner
that rolling dies positioned inside segment dies mounted outmost
are rotated, with the metal blank interposed between the rolling
dies being formed into the thread. At the moment, the metal blank
is moved at 1/2 speed of the rolling die.
[0007] Finally, a set of round dies is used. In one type of using
the round dies, two round dies are rotated about only their
rotational axes, respectively, with the metal blank being rotated
between both round dies. In the other type of using the round dies,
two round dies are rotated about their rotational axes, being
rotated around the metal blank interposed therebetween.
[0008] The first and third methods have an advantage in mass
production.
[0009] On the other hand, the shape and dimension of the metal
blank for the rolling may easily influence the life time of the
rolling die and the accuracy of the product. Accordingly, an
inappropriate shape of the base material causes the breakage or
higher wear of the rolling die.
[0010] In FIG. 1, there is shown a shaft for a starter motor which
has been newly developed in recent days. The starter motor has a
helical spline 1 having eight teeth and a spline 2 having four
teeth which are mounted on one shaft. It is difficult to form the
splines shaped like this, i.e., the two splines having different
tooth profiles by using a conventional rolling method.
[0011] That is, although one method where two types of splines are
simultaneously rolled was conventionally tried, the shape of one of
the splines after the rolling became useless since the two require
different rolling environments and different circumferential
speeds.
[0012] On the other hand, synchronizing the rotation of the spline
blank with the rotation of the rolling dies was applied. However,
the tooth of the rolling dies deviates from the tooth of the spline
blank during the rolling, failing to obtain a product with a proper
dimension.
SUMMARY OF THE INVENTION
[0013] It is, therefore, a primary object of the invention to
provide a rolling machine capable of performing a rolling of
different types of teeth at the same time.
[0014] In order to achieve the object, the present invention
provides a rolling machine for performing a rolling of different
types of teeth mounted on a shaft, the machine comprising: a
forming die including a first section and a second section provided
with a camming profiled circumferential surface of 360 degree, the
circumferential surface being divided into a guide surface of a
predetermined angle, a gradual forming surface of a predetermined
angle, a finishing section surface of a predetermined angle, and a
rotation stop section surface of a predetermined angle, which are
angularly positioned in that order on the circumferential surface;
a power transmitting device for transmitting and disconnecting a
driving force to the forming die; and a position detecting sensor
for controlling a stop timing of the forming die.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above and other objects and features of the instant
invention will become apparent from the following description of
preferred embodiments taken in conjunction with the accompanying
drawings, in which:
[0016] FIG. 1 illustrates a perspective view of a shaft of a
starter motor;
[0017] FIG. 2 shows a schematic perspective view of forming dies in
accordance with the present invention;
[0018] FIG. 3 depicts a frontal view of a second rolling section in
accordance with the present invention; and
[0019] FIG. 4 present a scheme of an inventive rolling machine
capable of forming different types of teeth simultaneously.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] A preferred embodiment of an inventive rolling machine is
described with reference to accompanying drawings.
[0021] FIG. 2 shows a schematic perspective view of forming dies in
accordance with the present invention, FIG. 3 depicts a frontal
view of a second rolling section in accordance with the present
invention, and FIG. 4 present a scheme of the inventive rolling
machine capable of forming different types of teeth
simultaneously.
[0022] As shown, a preferred embodiment of the present invention
examples a shaft of a starter motor(see FIG. 1) which has a helical
spline 1 having eight teeth and a spline 2 having four teeth which
are mounted on one shaft.
[0023] The inventive rolling machine is a roller type. As shown in
FIG. 2, the roller type rolling machine is provided with two
forming dies 10 whose rotational shafts are parallel with each
other. One forming die 10 is movable, while position of the other
is fixed, so that the forming dies 10 and a shaft blank, i.e., a
starter motor shaft spline blank rotate together, depressing
against one another.
[0024] In the roller type rolling machine, since the workpiece,
i.e., the shaft blank has a different circumferential length
between at a start point of the rolling and at an end point of the
rolling, it has to be rolled simultaneously.
[0025] As shown, each of the forming dies 10 has a first section 11
for forming the helical spline having eight teeth, and a second
section 12 for forming the spline having four teeth, which are
mounted on a same shaft.
[0026] The first section 11 and the second section 12 has a tooth
profile having a same pitch as that of a tooth of the a starter
motor shaft to be produced. The tooth of the first section 11 and
the second section 12 is offset to the tooth of the starter motor
shaft to be produced. That is, a crest of the tooth of the sections
11 and 12 corresponds to recess of the tooth of the starter motor
shaft to be produced.
[0027] On the other hand, since the first section 11 and the second
section 12 require rolling environments different from each other
and have different circumferential speeds, the start point of the
rolling has to be coincided every rotation.
[0028] For this, the forming dies 10 has a camming profile in its
cross-section instead of a real circle. A circumferential surface
of 360 degree of the forming dies 10 is divided into a guide
surface 13 of a predetermined angle, a gradual forming surface 14
of a predetermined angle, a finishing section surface 15 of a
predetermined angle, and a rotation stop section surface 16 of a
predetermined angle, which are angularly positioned in that
order.
[0029] In accordance with the present invention, the guide surface
13 has a same curvature so as to serve to guide at the beginning of
the rolling. accordingly, an amount of cutting advancement of the
forming dies 10 becomes very small. It is preferable that the guide
surface 13 range from 80 degree to 100 degree in the
circumferential surface of 360 degree.
[0030] In accordance with the present invention, the gradual
forming surface 14 has a crest of the tooth of the forming dies
which has a higher height along the circumference from an initial
point toward a completion point, to progressively form in the shaft
blank the helical spline having eight teeth and the spline having
four teeth. It is preferable that the gradual forming surface 14
range from 125 degree to 145 degree in the circumferential surface
of 360 degree. Further, the gradual forming surface 14 is
eccentrically formed to have a radius from a central axis which
becomes larger in 0.02 mm increment from tooth to tooth, so that it
progressively forms the tooth of the spline.
[0031] The finishing section surface 15 is contiguous to the
gradual forming surface 14 and has a range from 80 degree to 100
degree in the circumferential surface of 360 degree. The tooth
profile of the finishing section surface 15 is same as that of the
completion point of the gradual forming surface 14. On the other
hand, the rotation stop section surface 16 is formed between the
remainder angle about 35 to 55 degree in the circumferential
surface of 360 degree. Although the rotation stop section surface
16 does not have a tooth for performing the rolling of the tooth,
it functions to correct different rolling environments and the
different circumferential speeds. That is, when an initial point of
the rotation stop section surface 16 arrives at the workpiece, the
driving force is disconnected from the forming dies 10 and then the
rotation of the forming dies 10 is temporarily stopped. The driving
force is supplied to rotate the forming dies 10 at the beginning
point of the guide surface 13.
[0032] For this, the inventive rolling machine is provided with a
power transmitting device 20 for controlling the transmission of
the driving force to the forming dies 10, and a position detecting
sensor 30 for controlling the stop timing of the forming dies
10.
[0033] In accordance with the present invention, the power
transmitting device 20 includes a driving motor 21 for generating
the driving force, a driving shaft 24 receiving the driving force
from the driving motor 21, a clutch 23 for connecting and
disconnecting the driving force from the driving shaft 24, and a
brake 23 for stopping the rotation of the driving shaft 24.
[0034] The position detecting sensor 30 includes a driving force
disconnecting sensor 31 positioned at the initial point of the
rotation stop section surface 16, and a stop check sensor 32
positioned at a center portion of the rotation stop section surface
16. That is, the driving force disconnecting sensor 31 actuates the
clutch 20 to disconnect the driving force, when the initial point
of the rotations stop section surface 16 meets the shaft blank,
i.e., the workpiece, during the rotation of the forming dies 10.
Further, the stop check sensor 32 actuates the brake 23 to stop the
forming dies 10 being rotated due to the inertia after the
disconnection of the driving force.
[0035] Although the invent-ion has been shown and described with
respect to the preferred embodiments, it will be understood by
those skilled in the art that various changes and modifications may
be made without departing from the spirit and scope of the
invention as defined in the following claims.
* * * * *