FORM 2
THE PATENT ACT 1970
(39 of 1970)
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See Section 10, and rule 13)
1. TITLE OF INVENTION
GEAR GRINDING MACHINE
2. APPLICANT (S)
a) Name : MITSUBISHI HEAVY INDUSTRIES, LTD.
b) Nationality : JAPANESE Company
C) Address : 16-5, KONAN 2-CHOME,
MINATO-KU, TOKYO 1088215,
JAPAN
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention
and the manner in which it is to be performed : -
TECHNICAL FIELD
The present invention relates to a gear grinding machine for grinding a gear to be
machined by using a grinding wheel and relates particularly to a gear grinding
machine having a dressing function of dressing the grinding wheel.
BACKGROUND ART
Gear grinding machines have been conventionally provided to grind a gear with a
grinding wheel after heat treatment of the gear and thereby efficiently finish a tooth
surface of the gear. In such gear grinding machines, repeated grinding wears out
the grinding wheel, deteriorating the sharpness thereof. Accordingly, after a
predetermined number of gears are ground, dressing needs to be performed on the
worn grinding wheel to restore edges thereof to sharp edges.
Therefore, the conventional gear grinding machines are provided wit11 a dressing
device which dresses the worn grinding wheel wit11 a dresser. Such a gear grinding
machine provided with the dressing device is disclosed, for example, in Patent
Document 1.
PRIOR ART DOCUMENT
PATENT DOCUMENT
Patent Document 1: Japanese Patent Application Publication No. 2005-111600
SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
In the conventional gear grinding machine described above, a counter column is
provided to a rotary table holding a gear, at a position opposite a column supporting
a grinding wheel. Further, a turn ring is tumably supported on an outer periphery
of the counter column. Moreover, this turn ring is provided with grippers capable
of gripping the gear and a dressing device capable of dressing the grinding wheel.
Hence, loading and unloading of the gear is made possible by turning the gripper
relative to the rotary table, while dressing of the grinding wheel is made possible by
turning the dressing device relative to the grinding wheel supported on the column.
However, such a conventional gear grinding machine has the following risk. The
rotary table for attaching the gear is provided between the column and the counter
column. Accordingly, when the grinding wheel is to be dressed by the dressing
device with a relatively-large gear attached to the rotary table, the grinding wheel or
the dressing device may come into contact with the large gear during the dressing
operation.
Further, removing the gear from the rotary table before dressing the grinding wheel
is conceivable to solve such a problem. However, this gear removing and attaching
work is very extensive when the gear is large.
The present invention has been made to solve the problems described above, and an
object thereof is to provide a gear grinding machine capable of dressing a grinding
wheel with a gear attached, regardless of the size of the gear.
MEANS FOR SOLVING THE PROBLEMS
A gear grinding machine according to a first aspect of the present invention solving
the above problems is a gear grinding machine for performing grinding on a gear to
be machined by rotating the gear to be machined and a grinding wheel in mesh with
each other, characterized in that the gear grinding machine comprises: a rotary table
configured to hold the gear to be machined and to rotate about a workpiece rotation
axis; grinding wheel moving means for rotatably supporting the grinding wheel and
moving the grinding wheel relative to the workpiece rotation axis; a ring-shaped
turn table disposed coaxially with the rotary table at a position radially outside the
rotary table, and supported turnably about the workpiece rotation axis; dressing
means provided on the turn table and having a dresser capable of dressing the
grinding wheel; and table turning means for turning the turn table about the
workpiece rotation axis in such a way that the dressing means moves between a
dressing position where the dressing means is capable of dressing the grinding
wheel supported by the grinding wheel moving means and a retreat position where
the dressing means is retreated from the dressing position during the grinding.
A gear grinding machine according to a second aspect of the present invention
solving the above problems is characterized in that the table turning means turns the
turn table about the workpiece rotation axis in such a way that the dressing means
moves to a dresser replacement position where replacement of the dresser is
possible.
A gear grinding machine according to a third aspect of the present invention solving
the above problems is characterized in that the gear grinding machine further
comprises: a stationary table provided radially outside the rotary table and
configured to support the rotary table with the rotary table being rotatable about the
workpiece axis; and an annular groove provided in an radially-outer portion of the
stationary table and configured to house the turn table with the turn table being
turnable.
A gear grinding machine according to a fourth aspect of the present invention
solving the above problems is characterized in that the gear grinding machine
further comprises a grinding wheel receiving stage provided on the turn table and
configured in such a way that the grinding wheel is mounted on the gear grinding
wheel receiving stage, and
the table turning means turns the turn table about the workpiece rotation axis in
such a way that the grinding wheel receiving stage moves between a grinding wheel
replacement position where replacement of the grinding wheel in the grinding
wheel moving means is possible and a grinding wheel loading/unloading position
where loading and unloading of the grinding wheel to and from the grinding wheel
receiving stage is possible.
EFFECT OF THE INVENTION
In the gear grinding machine of the present invention, the turn table is turned about
the workpiece rotation axis at a position radially outside the rotary table which holds
the gear to be processed and which is rotated about the workpiece rotation axis, and
the dressing means is thereby moved between the dressing position and the retreat
position. This allows the grinding wheel to be dressed with the gear to be
machined attached to the rotary table, regardless of the size of the gear to be
machined.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a side view of a gear grinding machine according to an embodiment of the
present invention.
Fig. 2 is a plan view of the gear grinding machine according to the embodiment of
the present invention.
Fig. 3 is an enlarged view of a main portion of Fig. 1.
Fig. 4 includes views showing a state where a dressing device is set at a dressing
position. Specifically, Part (a) is a plan view of such state, and Part (b) is a
side view of such state.
Fig. 5 includes views showing a state where the dressing device is set at a dresser
replacement position and a grinding wheel receiving stage is set at a grinding
wheel replacement position. Specifically, Part (a) is a plan view of such state,
and Part (b) is a side view of such state.
Fig. 6 is a view showing a state where the dressing device is set at a retreat position
and the grinding wheel receiving stage is set at a grinding wheel
loading/unloading position.
MODE FOR CARRYING OUT THE INVENTION
A gear grinding machine of the present invention is described below in detail by
using the drawings.
EMBODIMENT
As shown in Figs. 1 and 2, a gear grinding machine 1 is provided with a bed 11. A
column 12 is supported on this bed 11 to be movable in a horizontal X-axis direction.
Moreover, a saddle 13 is supported on the column 12 to be movable up and down in
a vertical Z-axis direction. A grinding wheel head 14 is supported on this saddle 13
to be movable in an axial direction of a grinding wheel rotation axis 81 (horizontal
Y-axis direction).
In addition, a grinding wheel rotating motor 15 is provided in the grinding wheel
head 14. A grinding wheel shaft 16 is supported by the grinding wheel rotating
motor 15 to be rotatable about the grinding wheel rotation axis B1. Further, a
threaded grinding wheel 17 having a helical thread formed in an outer peripheral
surface thereof is detachably attached to the grinding wheel shaft 16.
Note that a grinding wheel attachment structure for attaching the grinding wheel 17
to the grinding wheel shaft 16 is as follows. First, flange members are fitted into a
through hole of the cylindrical grinding wheel 17 from both sides of the through
hole, respectively. Then, with the grinding wheel 17 held between flange portions
18 of the flange members, the grinding wheel 17 is fixedly attached to the grinding
wheel shaft 16.
Accordingly, the grinding wheel 17 can be moved in the X-axis direction, the Y-axis
direction, the Z-axis direction, and the axial direction of the grinding wheel rotation
axis B1 by driving the column 12, the saddle 13, and the grinding wheel head 14.
Moreover, the grinding wheel 17 can be rotated about the grinding wheel rotation
axis B1 via the grinding wheel shaft 16 by driving the grinding wheel rotating motor
15. Note that the column 12, the saddle 13, and the grinding wheel head 14 form
grinding wheel moving means for moving the grinding wheel 17.
Moreover, a cylindrical stationary table 21 is provided in an upper portion of the bed
11. A shaft-shaped rotary table 22 is supported at a position radially inside the
stationary table 21 via bearings 23a and 231, to be rotatable about a vertical
workpiece rotation axis C.
A table rotating motor 24 is provided between the stationary table 21 and the rotary
table 22. The table rotating motor 24 is formed of a stator 24a fixed on an inner
peripheral surface of the stationary table 21 and a rotor 24b fixed on an outer
peripheral surface of the rotary table 22. Further, a workpiece (gear to be
machined) W is attached on a top surface of the rotary table 22 via an attachment jig
25. Accordingly, the workpiece W can be thus rotated together with the rotary
table 22 about the workpiece rotation axis C by driving the table rotating motor 24.
Meanwhile, an annular groove 21a which is open at an upper portion thereof is
formed in a radially-outer portion of the stationary table 21 to extend in a
circumferential direction of the stationary table 21. A ring-shaped turn table 31 is
housed in the annular groove 21a with a bearing 32 in between to be turnable about
the workpiece rotation axis C. Specifically, the turn table 31 is disposed coaxially
with the stationary table 21 and the rotary table 31.
Moreover, as shown in Fig. 3, a turning gear 31a is formed in an outer peripheral
surface of the turn table 31 to extend in a circumferential direction thereof.
Furthermore, a positioning gear 31b is formed in a lower portion of an inner
peripheral surface of the turn table 31 to extend in a circumferential direction
thereof.
A hollow gear box portion 21b is formed integrally with the annular groove 21a.
The gear box portion 21b extends radially (X-axis direction) outward from the center
(workpiece rotation axis C) of the rotary table 21 to the opposite side from the
column 12. A table turning motor (table turning means) 33 is provided on an upper
portion of the gear box portion 21b at an outer end thereof. A driving shaft 34 of
the table turning motor 33 is disposed in the gear box portion 21b. A driving gear
34a is formed in an outer peripheral surface of the driving shaft 34 to extend in a
circumferential direction thereof.
An intermediate shaft 35 and a driven shaft 36 are rotatably supported in the gear
box portion 21b. The intermediate shaft 35 is provided with an upper intermediate
gear 35a and a lower intermediate gear 35b, while the driven shaft 36 is provided
with a driven gear 36a. Further, the driving gear 34a and the lower intermediate
gear 35b mesh with each other, the upper intermediate gear 35a and the driven gear
36a mesh with each other, and the driven gear 36a and the turning gear 31a mesh
with each other.
In addition, as shown in Figs. 1 and 3, a ring-shaped sliding member 37 and a
ring-shaped fixed member 38 are provided between an inner wall surface of the
annular groove 21a (i.e., an outer peripheral surface of the stationary table 21) and an
inner peripheral surface of the turn table 31, the sliding member 37 being arranged
above the fixed member 38.
A recessed cylinder portion 21c is formed in the inner wall surface of the annular
groove 21a. The sliding member 37 is supported by the cylinder portion 21c to be
slidable in the vertical direction. Moreover, hydraulic pressure can be supplied to
and released from an upper portion and a lower portion of the cylinder portion 21c.
The sliding member 37 moves downward when the hydraulic pressure is supplied
to the upper portion of the cylinder portion 21c and moves upward when the
hydraulic pressure is supplied to the lower portion of the cylinder portion 21c.
Moreover, a positioning gear 37a is formed in a bottom surface of the sliding
member 37. Meanwhile, the fixed member 38 is fixed in the annular groove 21a,
and a positioning gear 38a is formed in a top surface thereof.
The positioning gear 37a of the sliding member 37 can mesh with the positioning
gear 31b of the turn table 31 and the positioning gear 38a of the fixed member 38 in
the vertical direction. In other words, the positioning gears 31b, 37a, 38a form a
gear coupling, and positioning of the turn table 31 in a turning direction thereof is
performed by the meshing of these gears.
Hence, the turn table 31 can be rotated about the workpiece rotation axis C via the
gears 34a, 35a, 35b, 36a, and 31a by driving the table turning motor 33. In a state
where the sliding member 37 has slid to the uppermost position, the positioning gear
37a does not mesh with the positioning gears 31b and 38a, allowing the turn table 31
to turn. Meanwhile, in a state where the sliding member 37 has slid to the
lowermost position, the positioning gear 37a meshes with the positioning gears 31b
and 38a, allowing positioning of the turn table 31 in the turning direction to be
performed.
A dressing device (dressing means) 40 and a grinding wheel receiving stage 50 are
provided on a top surface of the turn table 31. Note that the dressing device 40 and
the grinding wheel receiving stage 50 are disposed respectively at positions shifted
from each other by 90" in phase in the circumferential direction of the turn table 31.
The dressing device 40 is a device for dressing the grinding wheel 17 and is formed
of a device main body 41 fixed on the top surface of the turn table 31, a dresser
rotating motor 42 provided on this device main body 41, and a disc-shaped dresser
43 detachably attached to the dresser rotating motor 42. Hence, the dresser 43 can
be rotated about a horizontal dresser rotation axis B2 by driving the dresser rotating
motor 42.
Meanwhile, the grinding wheel receiving stage 50 is a stage for mounting the
grinding wheel 17 and is formed of a receiving stage main body 51 detachably
attached on the top surface of the turn table 31 and a pair of left and right receiving
members 52 provided respectively on both widthwise sides of the receiving stage
main body 51. Note that the distance between the pair of the left and right
receiving members 52 are set to be the same as the distance between the flange
portions 18 provided in both end portions of the grinding wheel 17, and top surfaces
of these receiving members 52 are formed in an arc shape to allow the flange
portions 18 to be fitted thereto.
As shown in Figs. 1, 2, 4, and 6, positioning the turn table 31 by causing the turn
table 31 to turn at a predetermined turning angle allows the dressing device 40 to be
set at any of a dressing position Dl, a retreat position D2, and a dresser replacement
position D2 and also allows the grinding wheel receiving stage 50 to be set at a
grinding wheel replacement position GI or a grinding wheel loading/uidoading
position G2.
Here, the dressing position Dl (a state where the turning angle of the turn table 31 is
0") is a position where the dressing device 40 faces the grinding wheel 17 attached to
the grinding wheel shaft 16. Setting the dressing device 40 at the dressing position
Dl allows the grinding wheel 17 to be dressed by the dresser 43.
Moreover, the retreat position D2 (a state where the turning angle of the turn table
31 is 180") is a position where the dressing device 40 is farthest away from the
dressing position Dl, i.e. a position on a side opposite to the column 12 with a rotary
table 21 in between. Setting the dressing device 40 at the retreat position D2 allows
the workpiece W to be ground by the grinding wheel 17.
Furthermore, the dresser replacement position D3 (a state where the turning angle of
the turn table 31 is 90") is an intermediate position between the dressing position Dl
and the retreat position D2 and is a position facing a worker. Setting the dressing
device 40 at the dresser replacement position D3 allows the worker to replace the
dresser 43.
Meanwhile, the grinding wheel replacement position G1 (the state where the turning
angle of the turn table 31 is 90") is a position where the grinding wheel receiving
stage 50 faces the grinding wheel 17 attached to the grinding wheel shaft 16.
Setting the grinding wheel receiving stage 50 at the grinding wheel replacement
position G1 allows replacement of the grinding wheel 17 in the grinding wheel
head 14.
Moreover, the grinding wheel loading/unloading position G2 (the state where the
turning angle of the turn table 31 is 180") is a position facing the worker. Setting the
grinding wheel receiving stage 50 at the grinding wheel loading/unloading position
G2 allows the worker to load and unload (replace) the grinding wheel 17 onto and
from the grinding wheel receiving stage 50.
Next, operations of the gear grinding machine 1 are described by using Figs. 4 to 6.
When the workpiece W is to be ground by the grinding wheel 17, the grinding wheel
17 is first moved in the X-axis direction, the Y-axis direction, the Z-axis direction,
and the axial direction of the grinding wheel rotation axis B1 to stand by at a
position above or below the workpiece W attached to the attachment jig 25.
Then, the grinding wheel 17 is rotated about the grinding wheel rotation axis B1, and
the workpiece W is rotated about the workpiece rotation axis C. Thereafter, the
grinding wheel 17 is moved in the Z-axis direction and is made to mesh with the
workpiece W. Tooth surfaces of the workpiece W are thus ground by edge surfaces
of the grinding wheel 17.
Note that, in the grinding described above, as shown in Fig. 6, the turn table 31 is
turned to set the dressing device 40 at the retreat position D2 in advance.
Meanwhile, as illustrated by two-dot chain lines of Parts (a) and (b) of Fig. 4, the
grinding wheel receiving stage 50 is removed from the turn table 31 in advance.
When a certain number of workpieces W are ground by using the grinding wheel 17,
the edge surfaces thereof wears and the sharpness thereof deteriorates. Hence, the
grinding wheel 17 needs to be regularly dressed by the dresser 43.
When the grinding wheel 17 is to be dressed by the dresser 43, as shown in Parts (a)
and 4 (b) of Fig. 4, the turn table 31 is turned with the workpiece W attached to the
attachment jig 25, and the dressing device 40 is thereby moved from the reheat
position D2 to the dressing position Dl.
Next, the dresser 43 is rotated about the dresser rotation axis 82. Thereafter, the
grinding wheel 17 is moved in the X-axis direction, the Y-axis direction, the Z-axis
direction, and the axial direction of the grinding wheel rotation axis B1 and is made
to mesh with the dresser 43 set at the dressing position Dl.
Then, from this meshing state, the grinding wheel 17 is rotated about the grinding
wheel rotation axis B1 and is moved in the Y-axis direction and the axial direction of
the grinding wheel rotation axis B1. The edge surfaces of the grinding wheel 17 are
thus dressed by edge surfaces of the dresser 43.
Moreover, when the dresser 43 wears and is to be replaced with the new dresser 43
or when the dresser 43 is to be replaced with the dresser 43 of a different type
depending on an edge shape of the grinding wheel 17, as shown in Parts (a) and (b)
of Fig. 5, the turn table 31 is turned with the workpiece W attached to the attachment
jig 25 to move the dressing device 40 from the dressing position Dl or the retreat
position D2 to the dresser replacement position D3.
Then, the worker performs a replacement work of the dresser 43 for the dressing
device 40 set at the dresser replacement position D3.
Then, as shown in Parts (a) and (b) of Fig. 4, the turn table 31 is turned so that the
dressing device 40 for which the dresser replacement work has been completed is
moved from the dresser replacement position D3 to the dressing position Dl.
Thereafter, the grinding wheel 17 is subsequently dressed by the replaced dresser 43.
Instead, as shown in Fig. 6, the turn table 31 is turned so that the dressing device 40
for which the dresser replacement work has been completed is moved from the
dresser replacement position D3 to the retreat position D2. Thereafter, the replaced
dresser 43 is made to stand by for the next dressing.
Furthermore, when the grinding wheel 17 wears and is to be replaced with the new
grinding wheel 17 or when the grinding wheel 17 is to be replaced with the grinding
wheel 17 of a different type depending on a tooth profile of the workpiece W, the
turn table 31 is first turned with the workpiece W attached to the attachment jig 25,
and the worker attaches the empty grinding wheel receiving stage 50 to a
predetermined position of the turn table 31 at the grinding wheel loading/unloading
position G2.
Then, as shown in Part (a) of Fig. 5, the turn table 31 is turned so that the empty
grinding wheel receiving stage 50 is moved from the grinding wheel
loading/unloading position G2 to the grinding wheel replacement position GI.
Next, the grinding wheel 17 is moved in the X-axis direction, the Y-axis direction, the
Z-axis direction and the axial direction of the grinding wheel rotation axis B1 to be
mounted on the empty grinding wheel receiving stage 50 set at the grinding wheel
replacement position GI. At this time, the flange portions 18 of the grinding wheel
17 are fitted to the receiving members 52 of the grinding wheel receiving stage 50.
Subsequently, as shown in Part (b) of Fig. 5, the grinding wheel head 14 is moved in
the X-axis direction, the Y-axis direction, the Z-axis direction, and the axial direction
of the grinding wheel rotation axis 81 with the grinding wheel 17 mounted on the
ginding wheel receiving stage 50 to pull the grinding wheel shaft 16 out from the
grinding wheel 17. Hence, the grinding wheel 17 is separated from the grinding
wheel head 14.
Then, as shown in Fig. 6, the turn table 31 is turned to move the grinding wheel
receiving stage 50 having the grinding wheel 17 mounted thereon from the grinding
wheel replacement position GI to the grinding wheel loading/unloading
position G2.
Next, the worker performs the loading/unloading (replacement) work of the
grinding wheel 17 to and from the grinding wheel receiving stage 50 set at the
grinding wheel loading/unloading position G2. Specifically, the mounted grinding
wheel 17 is unloaded from the grinding wheel receiving stage 50 and the new
grinding wheel 17 is loaded onto the empty grinding wheel receiving stage 50.
Then, as shown in Part (b) of Fig. 5, the turn table 31 is turned to move the grinding
wheel receiving stage 50 having the new grinding wheel 17 mounted thereon from
the grinding wheel loading/unloading position G2 to the grinding wheel
replacement position GI.
Subsequently, as shown in Part (a) of Fig. 5, the grinding wheel head 14 is moved in
the X-axis direction, the Y-axis direction, the Z-axis direction, and the axial direction
of the grinding wheel rotation axis B1 with the grinding wheel 17 inounted on the
grinding wheel receiving stage 50 to fit the grinding wheel shaft 16 into the grinding
wheel 17. The new grinding wheel 17 is thus attached to the grinding wheel shaft
16, and the replacement of the grinding wheel 17 is completed.
Then, as shown in Fig. 6, the turn table 31 is turned to move the empty grinding
wheel receiving stage 50 from the grinding wheel replacement position GI to the
grinding wheel loading/unloading position G2. Thereafter, the grinding wheel
receiving stage 50 is detached by the worker.
In the embodiment described above, the gear grinding machine of the present
invention is applied to the gear grinding machine 1 employing a generating grinding
method using the threaded grinding wheel 17. However, the gear grinding
machine of the present invention may be applied to a gear grinding machine
en~ployinga profile grinding method using a disc-shaped grinding wheel.
In the gear grinding machine of the present invention, the turn table 31 is turned
about the workpiece rotation axis C at a position radially outside the rotary table 22
which holds the workpiece W and which is rotated about the workpiece rotation axis
C, and the dressing device 40 is thereby moved between the dressing position Dl
and the retreat position D2. Accordingly, a contact between the dressing device 40
and the workpiece W can be prevented. This allows the grinding wheel 17 to be
dressed by the dresser 43 with the workpiece W attached to the rotary table 22,
regardless of the size of the workpiece W.
Moreover, turning the turn table 31 to move the dressing device 40 to the dresser
replacement position D3 allows the dresser 43 to be easily replaced with the
workpiece W attached to the rotary table 22.
In addition, the annular groove 21a is provided in the radially-outer portion of the
stationary table 21 which rotatably supports the rotary table 22, and the turn table 31
is turnably housed in the annular groove 21a. This allows the turn table 31 to be
stably turned.
Furthermore, the turn table 31 is turned about the workpiece rotation axis C to move
the grinding wheel receiving stage 50 between the grinding wheel replacement
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position GI and the grinding wheel loading/unloading position G2. Accordingly,
a contact of the workpiece W with the grinding wheel receiving stage 50 and the
grinding wheel 17 mounted thereon is prevented. This allows the grinding wheel
17 to be easily replaced with the workpiece W attached to the rotary table 22,
regardless of the size of the workpiece W.
INDUSTRIAL APPLICABILITY
The present invention can be applied to a gear grinding machine designed to save
space.
WE CLAIM:
1 A gear grinding machine for performing grinding on a gear to be machined
by rotating the gear to be machined and a grinding wheel in mesh with each
other, characterized in that the gear grinding machine comprises:
a rotary table configured to hold the gear to be machined and to rotate about
a workpiece rotation axis;
grinding wheel moving means for rotatably supporting the grinding wheel
and moving the grinding wheel relative to the workyiece rotation axis;
a ring-shaped turn table disposed coaxially with the rotary table at a position
radially outside the rotary table, and supported turnably about the
workpiece rotation axis;
dressing means provided on the turn table and having a dresser capable of
dressing the grinding wheel; and
table turning means for turning the turn table about the workpiece rotation
axis in such a way that the dressing means moves between a dressing
position where the dressing means is capable of dressing the grinding wheel
supported by the grinding wheel moving means and a retreat position where
the dressing means is retreated from the dressing position during the
grinding.
2 The gear grinding maclune according to claim 1, characterized in that the
table turning means turns the turn table about the workpiece rotation axis in
such a way that the dressing means moves to a dresser replacement position
where replacement of the dresser is possible.
3 The gear grinding machine according to claim 1, characterized in that the
gear grinding machine further comprises:
a stationary table provided radially outside the rotary table and configured
to support the rotary table with the rotary table being rotatable about the
workpiece axis; and
an annular groove provided in an radially-outer portion of the stationary
table and configured to house the turn table with the turn table being
turnable.
4 The gear grinding machine according to claim 1, characterized in that
the gear grinding machine further comprises a grinding wheel receiving
stage provided on the turn table and configured in such a way that the
grinding wheel is mounted on the gear grinding wheel receiving stage, and
the table turning means turns the turn table about the workpiece rotation
axis in such a way that the grinding wheel receiving stage moves between a
grinding wheel replacement position where replacement of the grinding
wheel in the grinding wheel moving means is possible and a grinding wheel
loading/unloading position where loading and unloading of the grinding
wheel to and from the grinding wheel receiving stage is possible.