U.S. patent application number 12/534067 was filed with the patent office on 2010-03-11 for honing method and honing machine.
Invention is credited to Takahiro Azuma, Yasuo Tomita.
Application Number | 20100062692 12/534067 |
Document ID | / |
Family ID | 41131612 |
Filed Date | 2010-03-11 |
United States Patent
Application |
20100062692 |
Kind Code |
A1 |
Tomita; Yasuo ; et
al. |
March 11, 2010 |
HONING METHOD AND HONING MACHINE
Abstract
A honing processing technology for making uniform the load
applied to honing grindstones by cooperating the reciprocal motion
of the honing grindstones with the feeding and expanding motion at
high precision by a specified relation. Servo motors are used as
drive sources respectively for spindle reciprocal drive part and
grindstone depth cutting part, and these two servo motors are
mutually cooperated, and the feeding and expanding motion of the
honing grindstones is controlled to be synchronized and tuned with
the ascending and descending (reciprocal) motion of the honing tool
so that the processing load applied to the honing grindstones may
be averaged. Hence, without modifying the basis existing mechanical
elements, the load applied to the honing grindstones may be
averaged, and the honing process may be stabilized in precision and
enhanced in precision.
Inventors: |
Tomita; Yasuo;
(Kyotango-shi, JP) ; Azuma; Takahiro;
(Kyotango-shi, JP) |
Correspondence
Address: |
Cheng Law Group, PLLC
1100 17th Street, N.W., Suite 503
Washington
DC
20036
US
|
Family ID: |
41131612 |
Appl. No.: |
12/534067 |
Filed: |
July 31, 2009 |
Current U.S.
Class: |
451/61 ; 451/120;
451/155 |
Current CPC
Class: |
B24B 33/027 20130101;
B24B 33/02 20130101; B24B 33/06 20130101; B24B 33/089 20130101 |
Class at
Publication: |
451/61 ; 451/120;
451/155 |
International
Class: |
B24B 1/00 20060101
B24B001/00; B24B 5/00 20060101 B24B005/00; B24B 17/00 20060101
B24B017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 9, 2008 |
JP |
2008-231267 |
Claims
1. A honing method of honing the inner circumference of a work by
moving a honing tool having a honing grindstone reciprocally in the
axial direction of the inner circumference of the work, rotating
about the axial line, and feeding and expanding the honing
grindstone at a specific depth of cut by mechanical driving means,
wherein a spindle reciprocal driving servo motor and a depth
setting driving servo motor are used respectively as a spindle
reciprocal driving source for moving a rotational spindle having
the honing tool reciprocally in the axial direction of the inner
circumference of the work, and a depth cutting driving source for
feeding and expanding the honing grindstone, and the motions of the
two servo motors are mutually cooperated, so that the feeding and
expanding motion of the honing grindstone is controlled to be
synchronized and tuned with the reciprocal motion of the honing
tool in order that the processing load applied to the honing
grindstone may be made uniform.
2. The honing method according to claim 1, wherein the position
waveform in feeding and expanding motion of the honing grindstone
is controlled to be synchronized and tuned with the position
waveform in ascending and descending stroke motion of the honing
tool.
3. The honing method according to claim 2, wherein the control
configuration for synchronizing and tuning the feeding and
expanding motion with the reciprocal motion is controlled to form
preliminarily a position waveform in ascending descending stroke
motion of the honing tool and a position waveform in feeding and
expanding motion of the honing grindstone, to synchronize and tune
the position waveform in the feeding and expanding motion with the
position waveform in the ascending and descending stroke motion,
and to control the spindle reciprocal driving servo motor and the
depth setting driving servo motor to operate respectively at the
position waveform in the ascending and descending stroke motion and
the position waveform in the feeding and expanding motion of the
honing grindstone.
4. The honing method according to claim 3, wherein the operation to
synchronize and tune the position waveform in the feeding and
expanding motion with the position waveform in the ascending and
descending stroke motion is executed by mutually matching the start
point and end point in time in these both position waveforms, and
mutually matching the position change rates in these both position
waveforms.
5. The honing method according to claim 2, wherein the position
waveform in ascending and descending stroke motion of the honing
tool is a sinusoidal waveform.
6. The honing method according to claim 2, wherein the position
waveform in ascending and descending stroke motion of the honing
tool is a triangular waveform.
7. The honing method according to claim 2, wherein the feeding and
expanding amount of the honing grindstone is an expansion by a
specific amount per stroke in the ascending and descending stroke
of the honing tool.
8. A honing machine for moving a honing tool having a honing
grindstone reciprocally in the axial direction of the inner
circumference of a work, rotating about the axial line, and honing
the inner circumference of the work by the honing grindstone,
comprising: a rotational spindle supported to be movable
reciprocally in the axial direction of the inner circumference of
the work, and to be rotatable about the axial line, spindle
rotating means for rotating and driving the rotational spindle
about the axial line, spindle reciprocating means for moving the
rotational spindle reciprocally in the axial direction of the inner
circumference, a honing tool mounted on the leading end of the
rotational spindle, being provided with an expandable and
contractable honing grindstone having a wheel surface along the
inner circumference, grindstone depth cutting means for feeding and
expanding the honing grindstone of the honing tool with a specified
depth of cut, and control means for controlling automatically by
mutually cooperating with the spindle rotating means, spindle
reciprocating means, and grindstone depth cutting means, wherein
drive sources of the spindle reciprocating means and the grindstone
depth cutting means are realized respectively by a spindle
reciprocal driving servo motor and a depth setting servo motor, and
the control means mutually cooperates the motions of these two
servo motors, so that the feeding and expanding motion of the
honing grindstone is controlled to be synchronized and tuned with
the reciprocal motion of the honing tool in order that the
processing load applied to the honing grindstone may be made
uniform.
9. The honing machine according to claim 8, wherein the control
means is designed to control position waveform in feeding and
expanding motion of the honing grindstone so as to be synchronized
and tuned with the position waveform in ascending and descending
stroke motion of the honing tool.
10. The honing machine according to claim 9, wherein the control
configuration in the control means for synchronizing and tuning the
feeding and expanding motion with the reciprocal motion is
controlled to form preliminarily a position waveform in ascending
descending stroke motion of the honing tool and a position waveform
in feeding and expanding motion of the honing grindstone, to
synchronize and tune the position waveform in the feeding and
expanding motion with the position waveform in the ascending and
descending stroke motion, and to control the spindle reciprocal
driving servo motor and the depth setting driving servo motor to
operate respectively at the position waveform in the ascending and
descending stroke motion and the position waveform in the feeding
and expanding motion of the honing grindstone.
11. The honing machine according to claim 10, wherein the operation
in the control means to synchronize and tune the position waveform
in the feeding and expanding motion with the position waveform in
the ascending and descending stroke motion is executed by mutually
matching the start point and end point in time in these both
position waveforms, and mutually matching the position change rates
in these both position waveforms.
12. The honing machine according to claim 9, wherein the position
waveform in ascending and descending stroke motion of the honing
tool is a sinusoidal waveform.
13. The honing machine according to claim 9, wherein the position
waveform in ascending and descending stroke motion of the honing
tool is a triangular waveform.
14. The honing machine according to claim 9, wherein feeding and
expanding amount of the honing grindstone is an expansion by a
specific amount per stroke in the ascending and descending stroke
of the honing tool.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a honing method and a
honing machine, and more particularly to a honing technology of
honing while feeding a honing grindstone by force at a specified
depth of cut mechanically to the inner circumference of a
workpiece.
[0003] 2. Description of the Related Art
[0004] Honing process is known as one of the processing methods of
finishing the inner circumference of a workpiece (or work) to a
mirror-smooth surface. In this honing process, the honing
grindstone and the work are set in a relatively floating state, and
the honing grindstone is driven by rotary motions and reciprocal
motions, and the honing grindstone is expanded by spring repulsive
forces to finish the inner circumference of the work precisely.
[0005] In the conventional honing process, the honing grindstone
was pressed against the work by a specific force (spring repulsive
force), and the inner circumference of the work was cut off
gradually, but recently, same as in the grinding process, various
honing machines for honing by a high pressure or a forced depth of
cut are developed, and are presently used in the mainstream.
[0006] Honing machines of this kind are roughly classified into a
constant pressure processing method for feeding and expanding the
honing grindstone at a specific pressure by hydraulic driving means
or the like, and a forced depth setting (constant) processing
method for feeding and expanding the honing grindstone at a
specific depth of cut by mechanical driving means, and in the
honing machines of any method, from the preceding process by
drilling machine or boring machine, the process can immediately
transferred to the honing process by omitting the grinding process
of the like, that is, the conventional grinning process and the
honing process can be combined, and an efficient precision
finishing is realized.
[0007] In the honing process of forced depth setting (constant)
processing method, as mentioned above, while the rotating honing
grindstone is moved reciprocally in the axial direction of the
work, by mechanical driving means, the honing grindstone is
continuously fed and expanded at a specific dept of cut from the
beginning of depth setting process until the end of machining
processing by mechanical driving means, and in the conventional
processing cycle, mutual control of reciprocal motion of honing
grindstone (ascending and descending stroke motion) and feeding and
expanding motion is theoretically effected on the reciprocal motion
of the honing grindstone, and the feeding and expanding motion of
the honing grindstone is designed to be executed in gradual steps
by feeding at a specific stroke in the descending stroke, and is
stopped in the ascending stroke (see, for example, Japanese Patent
Application Laid-Open No. 2003-170344).
[0008] However, in such theoretical control configuration,
actually, as shown in FIG. 8, the reciprocal motion and the feeding
and expanding motion of the honing grindstone are not exactly
synchronized (non-synchronous), and the motions are independent
mutually (in FIG. 8, the broken-line waveform indicates the
position waveform in the ascending and descending stroke motion of
the honing grindstone, and the solid-line waveform indicates the
position waveform in the feeding and expanding motion of the honing
grindstone).
[0009] That is, theoretically, the feeding and expanding motion is
controlled so that one expanding command of the honing grindstone
is entered in every stroke of the reciprocal motion of the honing
grindstone (in the case of FIG. 8, an expanding command comes in
the intermediate position of the descending stroke of the honing
grindstone), but actually if the expanding command of the honing
grindstone is entered, structurally, a motion delay (time lag) of
the honing grindstone occurs, and it has not been specifically
clarified at which position of one stroke the honing grindstone is
expanded (fed in).
[0010] In such conventional grindstone depth cutting control, by
the feeding and expanding motion of the honing grindstone (depth
setting timing, depth setting speed, and depth of cut) in relation
to the reciprocal motion of the honing grindstone, a sudden load
may be applied to the honing grindstone when feeding and expanding
the honing grindstone, or the load on the honing grindstone may not
be stable but may fluctuate significantly, and abrasive grains of
the honing grindstone may drop off excessively and the state is not
always ideal for the honing grindstone, and much improvement has
been required from the viewpoint of stability of honing precision
or enhancement of precision.
BRIEF SUMMARY OF THE INVENTION
[0011] It is hence a primary object of the invention to present a
novel honing technology solving these conventional problems.
[0012] It is other object of the invention to present a honing
technology capable of stabilizing the precision and enhancing the
precision of honing process, in the honing process of forced depth
setting (constant) processing method, by cooperating between the
reciprocal motion and the feeding and expanding motion of the
honing grindstone at high precision with a specified relation, and
making uniform the load applied to the honing grindstone.
[0013] The honing method of the present invention is a method of
honing the inner circumference of a work by moving a honing tool
having a honing grindstone reciprocally in the axial direction of
the inner circumference of the work, rotating about the axial line,
and feeding and expanding the honing grindstone at a specific depth
of cut by mechanical driving means, in which a spindle reciprocal
driving servo motor and a depth setting driving servo motor are
used respectively as a spindle reciprocal driving source for moving
a rotational spindle having the honing tool reciprocally in the
axial direction of the inner circumference of the work, and a depth
cutting driving source for feeding and expanding the honing tool,
and the motions of the two servo motors are mutually cooperated, so
that the feeding and expanding motion of the honing grindstone is
controlled to be synchronized and tuned with the reciprocal motion
of the honing tool in order that the processing load applied to the
honing grindstone may be made uniform.
[0014] A preferred embodiment includes the following
configurations.
[0015] (1) The position waveform in feeding and expanding motion of
the honing grindstone is control to be synchronized and tuned with
the position waveform in ascending and descending stroke motion of
the honing tool.
[0016] (2) The control configuration for synchronizing and tuning
the feeding and expanding motion with the reciprocal motion is
controlled to form preliminarily a position waveform in ascending
descending stroke motion of the honing tool and a position waveform
in feeding and expanding motion of the honing grindstone, to
synchronize and tune the position waveform in the feeding and
expanding motion with the position waveform in the ascending and
descending stroke motion, and to control the spindle reciprocal
driving servo motor and the depth setting driving servo motor to
operate respectively at the position waveform in the ascending and
descending stroke motion and the position waveform in the feeding
and expanding motion of the honing grindstone.
[0017] (3) The operation to synchronize and tune the position
waveform in the feeding and expanding motion with the position
waveform in the ascending and descending stroke motion is executed
by mutually matching the start point and end point in time in these
both position waveforms, and mutually matching the position change
rates in these both position waveforms.
[0018] (4) The position waveform in ascending and descending stroke
motion of the honing tool is a sinusoidal waveform.
[0019] (5) The position waveform in ascending and descending stroke
motion of the honing tool is a triangular waveform. Herein, the
triangular waveform refers to a position waveform in ascending and
descending stroke motion at which the stroke speed of the honing
tool is uniform (the same meaning applies throughout the present
specification).
[0020] (6) The feeding and expanding amount of the honing
grindstone is an expansion by a specific amount per stroke in the
ascending and descending stroke of the honing tool.
[0021] The honing machine of the present invention is a honing
machine for moving a honing tool having a honing grindstone
reciprocally in the axial direction of the inner circumference of a
work, rotating about the axial line, and honing the inner
circumference of the work, including a rotational spindle supported
to be movable reciprocally in the axial direction of the inner
circumference of the work, and to be rotatable about the axial
line, spindle rotating means for rotating and driving the
rotational spindle about the axial line, spindle reciprocating
means for moving the rotational spindle reciprocally in the axial
direction of the inner circumference, a honing tool mounted on the
leading end of the rotational spindle, being provided with an
expandable and contractable honing grindstone having a wheel
surface along the inner circumference, grindstone depth cutting
means for feeding and expanding the honing grindstone of the honing
tool with a specified depth of cut, and control means for
controlling automatically by mutually cooperating with the spindle
rotating means, spindle depth setting means, and grindstone depth
cutting means, in which drive source of the spindle reciprocating
means and the grindstone depth cutting means are realized
respectively by a spindle reciprocal driving servo motor and a
depth setting servo motor, the control means mutually cooperates
the motions of these two servo motors, so that the feeding and
expanding motion of the honing grindstone is controlled to be
synchronized and tuned with the reciprocal motion of the honing
tool in order that the processing load applied to the honing
grindstone may be made uniform.
[0022] A preferred embodiment includes the following
configurations.
[0023] (1) The control means is designed to control position
waveform in feeding and expanding motion of the honing grindstone
so as to be synchronized and tuned with the position waveform in
ascending and descending stroke motion of the honing tool.
[0024] (2) The control configuration in the control device for
synchronizing and tuning the feeding and expanding motion with the
reciprocal motion is controlled to form preliminarily a position
waveform in ascending descending stroke motion of the honing tool
and a position waveform in feeding and expanding motion of the
honing grindstone, to synchronize and tune the position waveform in
the feeding and expanding motion with the position waveform in the
ascending and descending stroke motion, and to control the spindle
reciprocal driving servo motor and the depth setting driving servo
motor to operate respectively at the position waveform in the
ascending and descending stroke motion and the position waveform in
the feeding and expanding motion of the honing grindstone.
[0025] (3) The operation in the control means to synchronize and
tune the position waveform in the feeding and expanding motion with
the position waveform in the ascending and descending stroke motion
is executed by mutually matching the start point and end point in
time in these both position waveforms, and mutually matching the
position change rates in these both position waveforms.
[0026] (4) The position waveform in ascending and descending stroke
motion of the honing tool is a sinusoidal waveform.
[0027] (5) The position waveform in ascending and descending stroke
motion of the honing tool is a triangular waveform.
[0028] (6) The feeding and expanding amount of the honing
grindstone is an expansion by a specific amount per stroke in the
ascending and descending stroke of the honing tool.
[0029] According to the present invention, a spindle reciprocal
driving servomotor and a depth setting driving servo motor are used
respectively as a spindle reciprocal driving source for moving a
rotational spindle having a honing tool reciprocally in the axial
direction of the inner circumference of a work, and a depth cutting
driving source for feeding and expanding a honing grindstone of the
honing tool, and the motions of the two servo motors are mutually
cooperated, so that the feeding and expanding motion of the honing
grindstone is controlled to be synchronized and tuned with the
reciprocal motion of the honing tool in order that the processing
load applied to the honing grindstone may be made uniform, and
therefore the following effects are obtained, and in the forced
depth setting (constant) processing method, without modifying the
basic existing mechanical elements (not required to add sensor or
other additional mechanism), the reciprocal motion of the honing
grindstone and the feeding and expanding motion can be cooperated
at high precision in a specified relation, and the load applied to
the honing grindstone can be made uniform, and the honing
technology capable of stabilizing the precision and enhancing the
precision of honing process can be presented.
[0030] (1) Extension of Life of Honing Grindstone
[0031] According to the present invention, the motions of the
spindle reciprocal driving servo motor and the depth setting
driving servo motor are mutually cooperated, and the feeding and
expanding motion of the honing grindstone is synchronized and tuned
with the reciprocal motion of the honing tool so that the
processing load applied on the honing grindstone may be averaged,
and therefore excessive load is not applied to the honing
grindstone when feeding and expanding the honing grindstone, and a
tender feeding and expanding motion is realized for the honing
grindstone.
[0032] Specifically, when the feeding and expanding amount of the
honing grindstone is fixed at one stroke of the ascending and
descending stroke of the honing tool, and it can be expanded by a
fixed depth of cut, and since the feeding and expanding of the
honing grindstone can be executed depending on the stroke speed of
the honing tool, and dropping of abrasive grains of the honing
grindstone can be suppressed, and the life of the honing grindstone
may be substantially extended, and a honing grindstone of a long
life is realized.
[0033] (2) Stability of Precision
[0034] As mentioned above, excessive load is not applied to the
honing grindstone when feeding and expanding the honing grindstone,
and the load applied to the honing grindstone is uniform without
variations, and the precision of honing process is stabilized, and
the precision is enhanced.
[0035] (3) Control of Hole Shape
[0036] The feeding and expanding motion of the honing grindstone is
controlled to be synchronized and tuned with the reciprocal motion
of the honing tool, and the feeding and expanding motion of the
honing grindstone can be executed at a desired position depending
on the reciprocal stroke position of the honing tool, and the
processing hole shape of the work can be controlled as desired.
[0037] (4) Correction of Hole Shape
[0038] Since the processing hole shape of the work can be
controlled, the processing hole shape of the work can be corrected
appropriately.
[0039] These and other purposes and features of the present
invention will be fully appreciated and understood by reading the
following detailed description taken in conjunction with the
drawings and novel facts indicated in the accompanying claims.
BRIEF DESCRIPTION OF THE DRAWING
[0040] FIG. 1 is a front view showing a partial section of an
outline configuration of a honing machine in preferred embodiment 1
of the present invention.
[0041] FIG. 2 is a front sectional view showing a magnified view of
grindstone depth cutting part of the honing machine.
[0042] FIG. 3 is a block diagram of configuration of device control
part of the honing machine.
[0043] FIG. 4 is a block diagram of configuration of a servo
control part in the device control part.
[0044] FIG. 5 is a diagram for explaining the definition of
synchronizing and tuning of position waveform in feeding and
expanding motion of a honing grindstone in control of the device
control part and position waveform in ascending and descending
stroke of a honing tool.
[0045] FIG. 6 is a diagram showing the relation between ascending
and descending stroke motion of honing tool and feeding and
expanding motion of honing grindstone in the honing machine.
[0046] FIG. 7 is a diagram showing the relation between ascending
and descending stroke motion of honing tool and feeding and
expanding motion of honing grindstone in a honing machine in
preferred embodiment 3 of the present invention.
[0047] FIG. 8 is a diagram showing the relation between ascending
and descending stroke motion of honing tool and feeding and
expanding motion of honing grindstone in a conventional honing
machine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0048] Preferred embodiments of the present invention are
specifically described below while referring to the accompanying
drawings.
[0049] FIG. 1 to FIG. 7 show preferred embodiments of the present
invention, in which same constituent members or elements are
identified with same reference numerals throughout the
drawings.
Preferred Embodiment 1
[0050] A honing machine of the present invention is shown in FIG.
1, and specifically this honing machine is a vertical type machine
for machining an inner circumference Wa of a cylindrical processing
hole of a work W, and mainly includes a rotational spindle 2 having
a honing tool 1 at the leading end, a spindle rotational driving
part (spindle rotating means) 3, a spindle reciprocal driving part
(spindle reciprocating means) 4, a grindstone depth cutting part
(grindstone depth cutting means) 5, and a device control part
(control means) 6.
[0051] The honing tool (or honing head) 1 is detachably fitted to
the leading end of the rotational spindle 2, that is, at a lower
end 2a.
[0052] The inside of this honing tool 1 includes, as shown in FIG.
2, a plurality of honing grindstones 10, 10, . . . disposed so as
to be free to expand and contract in the radial direction, a cone
rod 11 for expanding and contracting these honing grindstones 10,
10, . . . , and a reset spring (not shown) for resetting the honing
grindstones 10, 10, . . . .
[0053] Each honing grindstone 10 has a wheel surface 10a along the
inner circumference Wa of the work W. The cone rod 11 is disposed
movably in vertical direction in the honing tool 1, and its wedge
11a at the leading end is a wheel expanding part for pressing a
wheel base 10b of each honing grindstone 10, and its base rod 11b
in the upper part is coupled to a wheel expanding rod 35 described
below. Although not shown in the drawing, the honing grindstones
10, 10, . . . are elastically forced in an always contracting
direction by the reset spring.
[0054] The honing grindstones 10, 10, . . . are expanded and opened
by the rising motion of the cone rod 11, and is contracted and
closed by the reset spring along with the rising motion of the cone
rod 11.
[0055] The rotational spindle 2 has the honing tool 1 at its lower
end, and is also coupled to the spindle rotational driving part 3
including a spindle drive shaft 15, power transmission parts 25a to
25c, a drive motor 16, and others, and to the spindle reciprocal
driving part 4 including a slide main body 18, a feed screw
mechanism 19, a drive motor 20, and others.
[0056] In other words, the rotational spindle 2 is rotatably
supported on the slide main body 18, and this slide main body 18 is
elevated and guided by a guide rail 22, and is driven by and
coupled to the feed screw mechanism 19 and the drive motor 20 as
the elevating drive source, and thereby the spindle reciprocal
driving part 4 is composed.
[0057] The guide rail 22 is extended straightly in the vertical
direction on a machine body 21, and a sliding part 18a of the slide
main body 18 is slidably guided and supported on this guide rail
22. In the sliding part 18a of the slide main body 18, a nut body
19a of the feed screw mechanism 19 is integrally coupled and fixed,
and this nut body 19a is extended in vertical direction
perpendicularly on the machine body 21, and is screwed to be
movable back and forth in vertical direction to a feed screw 19b
supported rotatably. The upper end of the feed screw 19b is driven
by and coupled to a motor shaft 20a of the drive motor 20 by way of
a coupling 23. This drive motor 20 is a servo motor integrally
incorporating a position detection sensor 73 such as rotary
encoder, and the rotation amount of the drive motor 20 detected by
this position detection sensor 73.
[0058] By rotation and driving of the motor shaft 20a of the drive
motor 20, the feed screw 19b of the ball screw mechanism 19 is
rotated, and the slide main body 18 which is integral with the nut
body 21b is moved in the vertical direction, and through this slide
body 18, the rotational spindle 2, that is, the honing tool 1 is
elevated and lowered. The ascending and descending motion of the
honing tool 1 is detected by the position detection sensor 73 built
in the drive motor 20, and the result of detection is sent to a
spindle reciprocal control part 71 of the device control part 6 as
described below.
[0059] The upper end part 2b of the rotational spindle 2 is driven
by and coupled to the spindle rotational drive part 3. That is, the
upper end part 2b of the rotational spindle 2 is spline-fitted to
the spindle drive shaft 15 provided rotatably on a head part 21a of
the machine body 21, and is coupled to this spindle drive shaft 15
so as to be movable relatively in the vertical direction (axial
direction) and rotatable integrally.
[0060] Specifically, the upper end part 2b of the rotational
spindle 2 is supported slidably in vertical direction on the head
part 21a of the machine body 21 by a rotary spline device 24, and
is connected coaxially, integrally and rotatably on the spindle
drive shaft 15.
[0061] The spindle drive shaft 15 is provided with a transmission
pulley 25a, and this transmission pulley 25a is coupled to a
transmission pulley 25c mounted on a motor shaft 16a of the drive
motor 16 by way of a transmission belt 25b. This drive motor 16 is,
for example, a servo motor integrally incorporating a position
detection sensor 63 such as rotary encoder, and the rotation amount
of the drive motor 16 is detected by the position detection sensor
63, and thereby the rotary motion of the honing tool 1 is
detected.
[0062] By rotation and driving of the drive motor 16, the
rotational spindle 2, that is, the honing tool 1 is rotated and
driven by way of the spindle drive shaft 15. The rotary motion of
the honing tool 1 is detected by the position detection sensor 63
built in the drive motor 16, and the detection result is sent to a
spindle rotation drive part 61 of the device control part 6
described below.
[0063] The grindstone depth cutting part 5 is to feed the honing
grindstones 10, 10, . . . by a specified depth of cut, and mainly
includes, as shown in FIG. 1 and FIG. 3, a grindstone depth cutting
drive part (depth setting driving means) 30, and a grindstone depth
cutting control part (depth setting control means) 62.
[0064] The wheel dept setting drive part 30 mechanically feeds the
honing grindstones 10, 10, . . . by a specified depth of cut, and
it specifically includes the cone rod 11 (FIG. 2) of the honing
tool 1, the wheel expanding rod 35 (FIG. 2), a depth setting drive
mechanism 36, and a drive motor 37.
[0065] The wheel expanding rod 35, although not shown specifically,
is disposed movably in the axial direction (vertical direction) in
a shaft hole provided in the lower half of the rotational spindle
2, and its lower end part 35a is coupled to a base rod 11b of the
cone rod 11 (see FIG. 2), and its upper end part (not shown) is
coupled to the depth setting drive mechanism 36.
[0066] The depth setting drive mechanism 36 moves the wheel
expanding rod 36 in the vertical direction (axial direction), and
mainly includes, same as in the prior art, a follower 40 coupled to
the wheel expanding rod 35, and a drive screw shaft member 41 for
moving the follower 40 vertically.
[0067] The follower 40 is disposed on the rotational spindle 2 so
as to be slidable relatively in the vertical direction, and is
coupled to the wheel expanding rod 35 disposed in the rotational
spindle 2 integrally in the vertical direction.
[0068] The follower 40 is engaged with the drive screw shaft member
41 so as to be free to screw back and forth in the vertical
direction by way of a female thread member (not shown) fixed
integrally therewith. This drive screw shaft member 41 is supported
on the slide main body 18 rotatably and parallel to the rotational
spindle 2.
[0069] The drive screw shaft member 41 is engaged with a depth
setting drive shaft 42 provided rotatably in the head part 21a of
the machine body 21. Specifically, the depth setting drive shaft 42
is supported parallel to the drive screw shaft member 41, and its
upper end part 42a is spline-fitted to a rotary gear shaft 43a of
the gear mechanism 43 provided rotatably in the head part 21a of
the machine body 21, and is coupled to this rotary gear shaft 43a
so as to be movable relatively in the vertical direction and
rotatable integrally.
[0070] Specifically, the upper end part 42a of the depth setting
drive shaft 42 is supported on the head part 21a of the machine
body 21 slidably in the vertical direction by means of a rotary
spline device 44, and is connected to the rotary gear shaft 43a
coaxially and rotatably integrally. This rotary gear shaft 43a is
engaged with a gear 43b, and this gear 43b is integrally mounted
and fixed on the motor shaft 37a of the drive motor 37. On the
other hand, the depth setting drive shaft 42 is driven by and
coupled to the upper end part 41a of the drive screw shaft member
41 by way of the gear mechanism 44.
[0071] The drive motor 37 is, for example, a servo motor integrally
incorporating a position detection sensor 64 such as rotary
encoder, and the rotation amount of the drive motor 37 is detected
by the position detection sensor 64, and thereby the feeding and
expanding motion of the honing grindstones 10, 10, . . . of the
honing tool 1 is detected.
[0072] By rotation and driving of the motor shaft 37a of the drive
motor 37, the depth setting drive shaft 42 is put in rotation, and
the drive screw shaft member 41 is put in rotation, and the
follower 40 engaged therewith so as to be free to screw back and
forth is relatively moved downward or upward on the rotational
spindle 2. That is, in the descending motion of the follower 40,
the integrally formed wheel expanding rod 35 pushes down the cone
rod 11, and the honing grindstones 10, 10, . . . are expanded. On
other hand, in the ascending motion of the follower 40, along with
the ascending motion of the wheel expanding rod 35, the honing
grindstones 10, 10, . . . are contracted and closed by a reset
spring (not shown) in the honing tool 1. The feeding and expanding
motion of the honing grindstones 10, 10, . . . is detected by the
position detection sensor 64 built in the drive motor 20, and the
detection result is sent to a grindstone depth cutting control part
62 of the device control part 6 described below.
[0073] The device control part 6 automatically controls by mutually
cooperating the motions of the control parts 3, 4, 5 of the honing
machine, and is specifically composed mainly of microcomputers such
as CPU, ROM, RAM and I/O port.
[0074] The device control part 6 stores processing programs for
executing honing process and other data, and is mainly composed of,
as shown in FIG. 3, a main control part 70, a spindle rotation
control part 61 for controlling the drive motor 16 as drive source
of the spindle rotation drive part 3, a spindle reciprocal control
part 71 for controlling the drive motor (servo motor for spindle
reciprocal drive) 20 as drive source of spindle reciprocal drive
part 4, and a grindstone depth cutting control part 62 for
controlling the drive motor (servo motor for grindstone depth
cutting) 37 as drive source of the grindstone depth cutting part
5.
[0075] The main control part 70 stores various information
necessary for driving of the drive sources 16, 20, 37 of the drive
parts 3, 4, 5, for example, the rotating speed and ascending and
descending speed of the honing tool 1, or the reference positions
(stroke positions) P.sub.1, P.sub.2 and stroke width S (see FIG. 2)
of the honing grindstones 10, 10, . . . , or the depth setting
speed and depth setting timing, entered and set properly and
selectively as NC (numerical control) data or through the keyboard
of the operation panel or the like, and the control parts 61, 62,
71 are controlled according to such data.
[0076] The spindle rotation control part 61, the spindle reciprocal
control part 71, and the grindstone depth cutting control part 62
are specifically servo amplifiers composed of an arithmetic part 80
and a motor control part 81 as shown in FIG. 4, and individually
detection signals from the position detection sensors 63, 73, 64
such as rotary encoders for detecting the number of revolutions of
the motor shafts 16a 20a, 37a of the drive motors 16, 20, 37 are
fed back and supplied into the arithmetic part 80, and this
arithmetic part 80 compares and calculates the entered detection
values (number of revolutions) with the command value (number of
revolutions) from the main control part 70, and supplies an
electric power in proportion to the error of the detection value
and the command value to the drive motors 16, 19, 37 so as to match
between the detection values and the command values on the basis of
the result of calculation.
[0077] In particular, the spindle reciprocal control part 71 and
the grindstone depth cutting control part 62 are operated according
to the command from the main control part 70, and the motions of
the drive motors 20 and 37 are mutually cooperated, so that the
feeding and expanding motions of the honing grindstones 10, 10, . .
. are synchronized and tuned with the reciprocal motion of the
honing tool 1 in order that the processing load applied to the
honing grindstones 10, 10, . . . is made uniform.
[0078] That is, according to the command from the main control part
70, the grindstone depth cutting control part 62 controls the
grindstone depth cutting servo motor 37 of the grindstone depth
cutting drive part (depth cutting means) 30 so that the processing
load applied to the honing grindstones 10, 10, . . . may be made
uniform.
[0079] More specifically, the position waveform in the feeding and
expanding motion of the honing grindstones 10, 10, . . . is
controlled to be synchronized and tuned with the position waveform
in the ascending and descending stroke motion of the honing tool 1,
and the feeding and expanding speed of the honing grindstones 10,
10, . . . is controlled to be proportional to the ascending and
descending stroke speed of the honing tool 1.
[0080] In this manner, by synchronizing and tuning the both
position waveforms, while the positioning of the honing tool 1 and
the honing grindstones 10, 10, . . . is controlled at high
precision, the feeding and expanding speed of the honing
grindstones 10, 10, . . . can be tuned with the ascending and
descending stroke speed of the honing tool 1.
[0081] Herein, synchronizing and tuning of the position waveform in
the feeding and expanding motion of the honing grindstones 10, 10,
. . . with the position waveform in the ascending and descending
stroke motion of the honing tool 1 may be defined as follows.
[0082] Referring to FIG. 5, the position change amount (the change
amount of the honing tool 1 in the axial direction) from the upper
end position P.sub.1 to the lower end position P.sub.2 (see FIG.
2), or from the lower end position P.sub.2 to the upper end
position P.sub.1 in the position waveform in the ascending and
descending stroke motion of the honing tool 1, that is, the stroke
width S per stroke (see FIG. 2), and the stroke time t (see (a) in
FIG. 5), and the position change amount per stroke time t in the
position waveform in the feeding and expanding motion of the honing
grindstones 10, 10, . . . , that is, the grindstone depth cutting
amount D (the change amount of the honing tool 1 in the radial
direction) (see (b) in FIG. 5) are determined by the processing
condition depending on the material and the design conditions of
the work W to be processed.
[0083] At this time, in the both position waveforms, it is defined
to be "tuned" when the position change rate is the same in the
position change amounts S and D at stroke time t, and it is defined
to be "synchronized" when the start point t.sub.1 and the end point
t.sub.2 in time are mutually same per stroke in the both position
waveforms. At this time, if the signs of + and - are reverse in the
position change amounts S and D, it is defined to be "tuned" if the
position change rates are the same.
[0084] In the illustrated preferred embodiment, as shown in FIG. 6,
the position waveform in the ascending and descending stroke motion
of the honing tool 1 is a sinusoidal waveform (the broken line
waveform in FIG. 6), and the position waveform in the feeding and
expanding motion of the honing grindstones 10, 10, . . . is a same
sinusoidal waveform (the solid line waveform in FIG. 6), and the
expanding timing and the expanding speed in the honing grindstones
10, 10, . . . are synchronized and tuned with the ascending and
descending stroke motion of the honing tool 1. That is, as shown in
FIG. 6, the feeding and expanding amount of the honing grindstones
10, 10, . . . is a specific expanding amount per stroke of the
ascending and descending (reciprocal) motion of the honing tool 1,
and when the ascending and descending stroke speed of the honing
tool 1 is zero, the feeding and expanding speed of the honing
grindstones 10, 10, . . . is also zero, and when the ascending and
descending stroke speed of the honing tool 1 is maximum, the
feeding and expanding speed of the honing grindstones 10, 10, . . .
is also maximum.
[0085] In a specific control configuration for synchronizing and
tuning the feeding and expanding motion of the honing grindstones
10, 10, . . . with the reciprocal motion of the honing tool 1, the
position waveform in the ascending and descending stroke motion of
the honing tool 1 and the position waveform in the feeding and
expanding motion of the honing grindstones 10, 10, . . . are
generated preliminarily, and the position waveform in the feeding
and expanding motion is synchronized and tuned with the position
waveform in the ascending and descending stroke motion, and the
servo motor 20 for spindle reciprocal drive of the spindle
reciprocal drive at 4 and the servo motor 37 for grindstone depth
cutting of the grindstone depth cutting drive part 30 are
controlled respectively by the position waveform in the ascending
and descending stroke motion and the position waveform in the
feeding and expanding motion of the honing grindstones.
[0086] In other words, the position waveform in the ascending and
descending stroke motion of the honing tool 1 (the motion position
waveform of the ascending and descending stroke axis (in the shown
example, the feed screw mechanism 19)) and the position waveform in
the feeding and expanding motion of the honing grindstones 10, 10,
. . . (the motion position waveform of the wheel expanding rod 35)
are generated preliminarily, and are controlled so that the feed
screw mechanism 19 (the servo motor 20 for spindle reciprocal
drive) and the wheel expanding rod 35 (the servo motor 37 for
grindstone depth cutting) may be operated by these position
waveforms respectively. In this case, the stroke width S is set in
condition in relation to the ascending and descending stroke, and a
command is issued to the stroke width S not to operate by the
position waveform (sinusoidal wave in the illustrated preferred
embodiment) in the ascending and descending stroke motion. On the
other hand, in the feeding and expanding motion, the extending
amount per stroke of the honing tool 1 is fixed and set in
condition (to prevent fluctuations of the processing cycle time),
and a command is issued to the expanding amount not to operate by
the position waveform (sinusoidal wave in the illustrated preferred
embodiment) in the feeding and expanding motion. In these motion
position waveforms, the position waveform in the feeding and
expanding motion is synchronized and tuned with the position
waveform in the ascending and descending stroke motion.
[0087] In this case, in synchronizing and tuning of the position
waveform in the feeding and expanding motion with the position
waveform in the ascending and descending stroke motion, the start
point and the end point in time in these motion position waveforms
are matched with each other, and the position change rates in the
both position waveforms are mutually matched.
[0088] Thus, the position waveform in the ascending and descending
stroke motion of the honing tool 1 and the position waveform in the
feeding and expanding motion of the honing grindstones 10, 10, . .
. are generated preliminarily; and these position waveforms are
synchronized and tuned, and the stroke motion of the honing tool 1
and the feeding and expanding motion of the honing grindstones 10,
10, . . . are controlled simultaneously to follow these position
waveforms, and the both motions can be completely synchronized and
tuned, and time lag between the both motions can be prevented
effectively.
[0089] By feeding and expanding the honing grindstones 10, 10, . .
. by the same sinusoidal waveform and the same timing as the speed
change of the ascending and descending stroke of the honing tool 1
(that is, by synchronizing and tuning), the pressure of the contact
surface of the honing grindstones 10, 10, . . . and the inner
circumference Wa of the processing hole of the work W, that is, the
load applied to the honing grindstones 10, 10, . . . per stroke is
dispersed and averages.
[0090] For example, in the conventional processing cycle shown in
FIG. 8, regarding the ascending and descending stroke motion of the
honing tool 1, this ascending and descending stroke motion is
monitored, and depending on the speed changes, the honing
grindstones 10, 10, . . . are fed and expanded in gradual stages
(one feeding and expanding motion carried out per stroke of the
ascending and descending stroke motion of the honing tool 1), but
it is not exactly synchronized and tuned with the ascending and
descending (reciprocal) motion of the honing tool 1, and a time lag
occurs, and for example, when the ascending and descending stroke
speed of the honing tool 1 is zero, the feeding and expanding speed
of the honing grindstones 10, 10, . . . is maximum, and at this
time, it has been experimentally known that the pressure of the
contact surface of the honing grindstones 10, 10, . . . and the
inner circumference Wa of the processing hole of the work W
increases momentarily.
[0091] In this preferred embodiment, since the servo motors 20, 37
are provided as drive sources for spindle reciprocal drive part 4
and grindstone depth cutting part 5, the time per stroke in the
ascending and descending stroke of the honing tool 1 is divided
into multiple sections (2048 sections in the illustrated preferred
embodiment), and the ascending and descending stroke position of
the honing tool 1, and the feeding and expanding position of the
honing tools 10, 10, . . . are mutually positioned at each time
point of the multiple divided sections, and the honing grindstones
10, 10, . . . are expanded smoothly, and expansion gentle for the
honing grindstones 10, 10, . . . is realized. That is, for example,
as compared with the conventional processing cycle shown in FIG. 8,
in this conventional processing cycle, one feeding and expanding
motion is carried out per stroke of the ascending and descending
stroke motion of the honing tool 1, whereas in this preferred
embodiment, one stroke of ascending and descending stroke motion of
the honing tool 1 is divided into 2048 sections, and the feeding
and expanding motion is divided, and the pressure applied to the
wheels when feeding the honing grindstones 10, 10, . . . is
effectively dispersed.
[0092] For example, in the illustrated preferred embodiment, the
stroke width S is 50 mm, and the stroke speed is 15 m/min, and one
reciprocal time of ascending and descending stroke is 0.4 sec, and
this 0.4 sec is divided into 2048 sections and controlled.
[0093] Therefore, in the honing machine having such configuration,
the motions of the spindle rotational drive part 3, spindle
reciprocal drive part 4, and grindstone depth cutting part 5 are
mutually cooperated and controlled automatically by the device
control part 6, and the honing tool 1 is operated in a uniform
honing process (honing processing method) at a specific depth of
cut over the entire honing region (that is, the stroke width S in
FIG. 2), on the inner circumference Wa of the work W supported on
the work holding jig 8.
[0094] That is, the honing tool 1 is rotated about the axial line
of the inner circumference Wa of the work W by the spindle
rotational drive part 3, and is moved reciprocally about the axial
line of the inner circumference Wa of the work W by the spindle
reciprocal drive part 4, and the honing grindstones 10, 10, . . .
are fed and expanded by a specific depth of cut by the grindstone
depth cutting part 5, and thereby the inner circumference Wa of the
work W is processed by honing.
[0095] At this time, the feeding and expanding motion of the honing
grindstones 10, 10, . . . is mutually cooperated with the motions
of the drive motors 20 and 37, and is controlled to be synchronized
and tuned with the ascending and descending (reciprocal) motion of
the honing tool 1, so that the processing load applied to the
honing grindstones 10, 10, . . . may be averaged (see FIG. 5).
[0096] Thus, according to the honing processing method of the
present preferred embodiment, the servo motor for spindle
reciprocal drive and the servo motor for depth cutting drive are
used respectively as the drive motor 20 for spindle reciprocal
drive part 4 and the drive motor 37 for wheel depth cutting part
(wheel depth cutting means) 5, and the motions of these two servo
motors are mutually cooperated, and the feeding and expanding
motion of the honing grindstones 10, 10, . . . is controlled by
synchronizing and tuning with the ascending and descending
(reciprocal) motion of the honing tool 1, so that the processing
load applied to the honing grindstones 10, 10, . . . may be
averaged, and therefore the following effects are obtained, and in
this kind of forced depth setting (constant) honing process,
without modifying the basic existing mechanical elements, the
feeding and expanding motion can be cooperated with the reciprocal
motion of the honing grindstones 10, 10, . . . at high precision
with a specified relation, and the processing load applied to the
honing grindstones 10, 10, . . . can be made uniform substantially,
and a honing technology capable of stabilizing the precision of
honing process and enhancing the precision may be presented.
(a) Extension of Life of Honing Grindstones 10, 10, . . .
[0097] According to the honing method of the present preferred
embodiment, as mentioned above, the servo motor 20 for spindle
reciprocal drive and the servo motor 37 for depth setting drive are
mutually cooperated, and the feeding and expanding motion of the
honing grindstones 10, 10, . . . is controlled by synchronizing and
tuning with the ascending and descending (reciprocal) motion of the
honing tool 1, so that the processing load applied to the honing
grindstones 10, 10, . . . may be averaged, and therefore sudden
load is not applied to the honing grindstones 10, 10, . . . when
feeding and expanding the honing grindstones 10, 10, . . . , and a
tender feeding and expanding motion for the honing grindstones is
realized.
[0098] Specifically, when the feeding and expanding amount of the
honing grindstones 10, 10, . . . is fixed at one stroke of the
ascending and descending stroke of the honing tool 1, and it can be
expanded by a fixed depth of cut, and since the feeding and
expanding of the honing grindstones 10, 10, . . . can be executed
depending on the stroke speed of the honing tool 1, and therefore
sudden load is not applied to the honing grindstones 10, 10, . . .
, and dropping of abrasive grains of the honing grindstones 10, 10,
. . . can be suppressed, and the life of the honing grindstones 10,
10, . . . may be substantially extended, and honing grindstones 10,
10, . . . of a long life are realized.
[0099] In other words, the fast stroke speed of the honing tool 1
means that the distance is long for dividing the work W by the
honing grindstones 10, 10, . . . per unit time and dropping of
abrasive grains of the honing grindstones 10, 10, . . . is
significant per unit time. In this preferred embodiment, the depth
setting speed is increased in a position where dropping of abrasive
grains of the honing grindstones 10, 10, . . . is significant, and
the depth setting speed is decreased in a position where dropping
of abrasive grains of the honing grindstones 10, 10, . . . is less
significant, and therefore the pressure load applied to the honing
grindstones 10, 10, . . . is effectively dispersed and
averaged.
(b) Stability of Precision
[0100] As mentioned above, sudden load is not applied to the honing
grindstones 10, 10, . . . when feeding and expanding the honing
grindstones 10, 10, . . . , and the load applied to the honing
grindstones 10, 10, . . . is uniform without variations, and the
precision of honing process is stabilized, and the precision is
enhanced.
(c) Control of Hole Shape
[0101] The feeding and expanding motion of the honing grindstones
10, 10, . . . is controlled to be synchronized and tuned with the
ascending and descending (reciprocal) motion of the honing tool 1,
and the feeding and expanding motion of the honing grindstones 10,
10, . . . can be executed at a desired position depending on the
ascending and descending (reciprocal) stroke position of the honing
tool 1, and the processing hole shape of the work W can be
controlled as desired.
Preferred Embodiment 2
[0102] This preferred embodiment is shown in FIG. 7, and is similar
to preferred embodiment 1, except that the position waveforms in
the feeding and expanding motion of the honing grindstones 10, 10,
. . . are modified.
[0103] That is, in this preferred embodiment, the position waveform
in the ascending and descending stroke motion of the honing tool 1
is a triangular waveform (broken line waveform in FIG. 7), and the
position waveform in the feeding and expanding motion of the honing
grindstones 10, 10, . . . is a linear waveform to be synchronized
and tuned with this triangular waveform (solid line waveform in
FIG. 7).
[0104] More specifically, the ascending and descending stroke speed
of the honing tool 1 is a specified uniform stroke in the ascending
stroke and the descending stroke, whereas the feeding and expanding
amount of the honing grindstones 10, 10, . . . is set at a specific
depth of cut per stroke of the ascending and descending
(reciprocal) motion of the honing tool 1, and the feeding and
expanding speed is controlled to a specified uniform speed.
[0105] The other configuration and action are same as in preferred
embodiment 1.
[0106] The foregoing preferred embodiments 1 and 2 show preferred
embodiments of the present invention, but the present invention is
not limited to these preferred embodiments, but may be changed and
modified in design within the scope thereof. For example, the
following modifications may be, possible.
[0107] The position waveform in the ascending and descending stroke
motion of the honing tool 1 and the position waveform in the
feeding and expanding motion of the honing grindstones 10, 10, . .
. are not limited to those shown in the illustrated preferred
embodiments (FIG. 5 and FIG. 6), as far as being synchronized and
tuned with the reciprocal motion of the honing tool 1, and; for
example, the position waveform in the ascending and descending
stroke motion of the honing tool 1 may be modulation waveform.
[0108] The specific embodiments mentioned in the detailed
description of the invention are illustrative and not restrictive,
and since the scope of the present invention is defined by the
appended claims rather than by the description preceding them, and
all changes that fall within metes and bounds of the claims, or
equivalence of such metes and bounds thereof are therefore intended
to be embraced by the claims.
* * * * *