DESC:
FIELD OF INVENTION
The present invention relates to a gear grinding machine. More particularly, the present invention relates to a grinding machine for grinding of a gear, which has direct power transmission. Furthermore particularly, the present invention relates to a gear grinding machine having a controller with open architecture and user friendly screens. Advantageously, the present invention improves the accuracy of gears while grinding.

DESCRIPTION OF PRIOR ART
Gear grinder, is usually employed as the final machining process when manufacturing a high-precision gear. The primary function of the gear grinder is to remove the remaining few thousandths of a micron of material left by other manufacturing methods such as shaping, gashing or hobbing. Conventionally, Gear grinding machines are configured to sequentially grind the tooth surfaces of a gear mounted on a rotary table by rotating the gear and inserting the circumference of a worm type grinding wheel, profile generated as a mirror image/reverse involute profile of a gear which is being driven to rotate, into each tooth space of the gear.

The gear's meshing accuracy can be improved thereby improving the accuracy of the gear component. Such a gear grinding machine cannot properly grind the tooth surfaces of the gear when the axis of the gear is displaced with respect to the axis of the rotary table. Thus, the axis of the rotary table and the axis of the gear need to be accurately positioned to each other. However, in a case of machining a large-sized gear measuring several meters in diameter, the centering cannot be done easily because such a gear is extremely heavy, weighing several tons.

US5857896 discloses a device for the fine machining of spur or helical gear wheels comprising a work-piece spindle that can be shifted parallel to the spindle axis and a toothed dressing wheel is mounted on which the globoid grinding worm is periodically dressed. A toothed honing wheel is lodged rotatably on an additional arm. The toothed honing wheel is dressed on the same or a second toothed dressing wheel. The device makes possible an efficient fine machining of toothed wheels. However the spur gear and helical gears cannot be grinded with high accuracy.

US5857894 discloses a grinding machine for the grinding of spur or helical gear wheels comprising work-piece spindle is mounted for rotation around a vertical axis (C). A slide bears a linear guide element able to be swiveled around a horizontal axis (A) and on which a second slide can be shifted. The slide bears the grinding spindle (axis B) with mounted grinding worm. A dressing device is arranged, relative to the axis (C1), opposite the work-piece spindle. The machine makes easy operation possible, because all parts to be operated are quite accessible. However the accuracy of the grinding of the spur and helical gear wheels is less.
US4631870 discloses a CNC grinding machine comprising base having a first plane surface which can be defined by two axes perpendicular with each other, a work station driven by a first servomechanism to be capable of moving on the first plane surface and rotating about a third axis perpendicular to the first plane surface. The CNC system controls the servomechanisms so that a work piece can be worked and measured according to instructions stored therein and a computer connected to the CNC system and capable of governing the instructions. However the controller has no open architecture and user friendly screens.

US4991353 discloses a grinding machine for grinding pregeared bevel gears in which the grinding of both flanks of the tooth gap is performed in a single setting and by a single tool in a hobbing process. The grinding machine is provided with a truing device rigidly connected to a stationary part of the machine, and a truing tool is pivotable relative to the grinding wheel to adjust an angle of engagement therebetween. An oscillating movement is imparted to the grinding head carrying the grinding wheel radially relative to the bevel gear being ground and a compensating movement in the direction perpendicular to the oscillating movement is also imparted to the grinding wheel, whereby the grinding of the pregeared bevel gears of any profiles is possible. However the axis of the rotary table and the axis of the gear need to be accurately positioned to each other.

US5175962 discloses a method of and apparatus for machining spur and helical gears comprising the outer tooth surfaces of a theoretical ring gear are conjugate to the grinding surfaces along the width of a generally hourglass shaped grinding wheel. The grinding wheel is rotated which in turn causes the theoretical ring gear to rotate. A work gear is rotated in mesh with the internal tooth surfaces of the theoretical ring gear and simultaneously is traversed in mesh across the width of the grinding wheel with the center of the work gear moving in a path about the center of the theoretical ring gear. However the spur gear and helical gears cannot be grinded with high accuracy.

Accordingly, there exists a need for a grinding machine for grinding of a gear, which has direct power transmission.

OBJECTS OF INVENTION
It is the primary object of the present invention to provide a gear grinding machine for generation grinding of a gear by basic rack pofile grinding wheel , which has direct power transmission.

It is another object of the present invention to provide a grinding machine for grinding of a gear, which improves the required tooth form of gears while grinding.

It is another object of the present invention to provide required tooth form of gears with class DIN 5 accuracy.
It is another object of the present invention to provide a grinding machine for grinding of a gear, which consists of HMT Num CNC controller with open architecture and user friendly screens.

It is another object of the present invention to provide a grinding machine for grinding of a gear, which is capable of grinding spur and helical gears.

It is another object of the present invention, wherein the direct driven rotary table ensures high speed, high acceleration or deceleration, zero backlash and super- precision positioning.

It is another object of the present invention, wherein the swivelling grinding head with high precision bearing surfaces insure ultra smooth swiveling and clamped in position by a hydraulic clamping arrangement guided by T-slot and T-nut.

It is another object of the present invention, wherein the grinding wheel spindle runs on high precision bearings lubricated to increase its durability.

These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
SUMMARY OF INVENTION
One or more of the problems of the conventional prior art may be overcome by various embodiments of the present invention.

It is another object of the present invention to provide a gear grinding machine, comprising of:
a bed [1];
a column [2];
an axial feed drive or Z-axis [3];
a vertical slide [4];
a swiveling grinding head or A-Axis [5];
a wheel slide [7];
a direct driven rotary table or C-Axis [9];
a radial feed drive or X-axis [10];
a steady column [11];
a basic rack profile grinding wheel [17];
a table slide [18];
a basic rack profile diamond dresser [19];
a gear [20] and
a controller,
wherein the column [2] with ribs are mounted on the bed [1],
wherein the vertical slide [4] carries the swiveling grinding head or A-axis [5], a wheel head or B-axis [8] and moves on the prismatic guide ways of the column [2],
wherein the work piece or the gear [20] is clamped on the mechanical fixture [14] on the direct driven rotary table or C-axis [9],
wherein the basic rack profile type grinding wheel [17] is dressed by basic rack profile diamond dresser [19] mounted on a dresser slide [12] driven by motor which slides up and down by hydraulic cylinder controlled by limit switches mounted at the front side of the steady column [11],
wherein the direct driven rotary table [9] moving on the prismatic guide ways in bed [1] provides radial feed drive or X-axis [10] through directly coupled ball screw and nut,
wherein the axial feed drive or Z-axis [3] moves the wheel head or B-axis [8] along with vertical slide [8] up and down,
wherein the steady column [11] is mounted on the table slide [18], houses dresser slide [12], dresser head [13] and a vertically mounted hydraulic cylinder,
wherein the dresser slide [12] is clamped with the steady column [11] in position through hydraulic clamping arrangement, and moves up and down by piston cylinder arrangement,
wherein the controller is a Computer Numeric Control (CNC) controller.
It is another object of the present invention, wherein the basic rack profile type grinding wheel [17] grinds both spur gears and helical gears.

It is another object of the present invention, wherein a basic rack profile diamond dresser [17] is driven by direct driven dresser spindle.

It is another object of the present invention, wherein the basic rack profile diamond dresser [17] is changed to obtain different module of the gear, pressure angle and with or without root grinding feature.

It is another object of the present invention, wherein the swiveling grinding head [5] mounts the tangential feed drive or Y-axis [6], wheel slide [7] and wheel head or B-axis [8].

It is another object of the present invention, wherein the grinding operation is carried out by synchronizing wheel head or B-axis [8] and direct driven rotary table or C Axis [9].

It is another object of the present invention, wherein the wheel head or A-axis [5] is swiveled for the grinding of helical gear.

It is another object of the present invention, wherein the grinding is done upto the root of the gear [20] by the X axis or radial feed drive [10].
It is another object of the present invention, wherein the swiveling grinding head [5] is mounted on the vertical slide [4] carries the motorized grinding wheel head, and performs swiveling through a worm and worm wheel, driven by the AC servo motor.

It is another object of the present invention, wherein the bed [1] is made up of high grade cast iron having prismatic guideways and encases mechanical, hydraulic and electrical control units of the gear grinding machine.

It is another object of the present invention, wherein the column [2] is a rigid frame attached to the bed [1], having prismatic guideways, houses Z axis or axial feed drive [3], a vertical slide [4] and swiveling head [5], and carries a dog mounting rail.

It is another object of the present invention, wherein the vertical slide [4] is balanced by counter weights [15] guided by guide rod mounted on the column, moves vertically on precision scrapped guide ways on the column [2] by ball screw and nut driven by AC servomotor.

It is another object of the present invention, wherein the precision movement of the vertical slide [4] by precision prismatic guide and Gib& Guide piece.

It is another object of the present invention, wherein the grinding wheel spindle and the direct drive rotary table [9], dresser spindle are provided with cooling system.
It is another object of the present invention, wherein shifting of the basic rack profile type grinding wheel [17] is effected by the ball screw driven by the motor through a timer belt, and pulley during dressing as well as during grinding.

It is another object of the present invention, wherein corresponding guideways of the prismatic guideways of the column [2], vertical slide [4], radial feed drive or X-axis [10], and dresser slide [12] are coated with turcite material.

BRIEF DESCRIPTION OF THE DRAWING:
So that the manner in which the features, advantages and objects of the invention, as well as others which will become apparent, may be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiment thereof which is illustrated in the appended drawing, which form a part of this specification. It is to be noted, however, that the drawing illustrate only a preferred embodiment of the invention and is therefore not to be considered limiting of the invention's scope as it may admit to other equally effective embodiments.

Figure 1: illustrates the right side view of the grinding machine for grinding of a gear according to the present invention.
Figure 2: illustrates the front view of the grinding machine for grinding of a gear according to the present invention.
Figure 3: illustrates the left side view of the grinding machine for grinding of a gear according to the present invention.
Figure 4: illustrates the top view of the grinding machine for grinding of a gear according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION
The present disclosure as herein described relates to a gear grinding machine. Referring to the figures, the present embodiment comprises a bed [1], a column [2], an axial feed drive or Z-axis [3], a vertical slide [4], a swiveling grinding head or A-Axis [5], a wheel slide [7] or Y- Axis, a direct driven rotary table or C-Axis [9], a radial feed drive or X-axis [10],a steady column [11], a basic rack profile type grinding wheel [17], a table slide [18], a basic rack profile diamond dresser [19] and a controller.

The machine is offered with state of the CNC system and drive units. High gain amplifiers are used to drive the AC servomotors for maintenance free operation. The CNC system has features like jog, offsets, electronic hand wheel etc., for the convenience of the operator and to reduce the setup time. It is very easy to change over from one application to another and combine the applications to suit the component being ground to improve the productivity of the machine.

Gear grinding machine is used grinding pre-geared spur and helical gears in which the grinding of both flanks and root is performed by generating gear grinding process, through synchronizing electronic gearing of both B-Axis or wheel head [8] and C-Axis Direct driven rotary table [9].The replica image of the basic rack profile of the basic rack profile grinding wheel [17] is formed on the pre-geared gear so as to get the involute profile. The radial feed of the gear [20] is controlled by Z-Axis movement.

The gear grinding machine, preferably a computer numerical control (CNC) gear grinding machine GGM250 is designed for performing external grinding operations on work piece clamped in fixtures [14] mounted on direct driven rotary table or C-Axis [9] by generating type grinding. The basic rack profile type grinding wheel [17] facilitates in grinding of both spur and helical gear grinding. The basic rack profile type grinding wheel [17] is dressed by basic rack profile diamond dresser mounted on dresser slide [12] driven by direct drive motor slides up and down by hydraulic cylinder controlled by limit switches mounted at the front side of the steady column [11]. The applicable grinding operation is carried out by synchronising electronic gearing of B and C Axes . The entire width of the spur gear is finished by moving vertical slide head up and down with the help of Z axis. However, using the wheel head [8] is swiveled for helical gear grinding. The grinding is done upto the root of the gear by the X axis or radial feed drive [10].

The machine is designed to meet the static and dynamic requirements of gear grinding to produce the required tooth form with class DIN 5 accuracy in spite of interrupted cuts speciallity of gear grinding process.

According to a first illustrative embodiment, the column [2] with ribs is mounted on the bed [1]. The vertical slide [4] carries the swiveling head or A-axis [5], a wheel head or B-axis [8] and moves on the prismatic guideways of the column [2]. The table slide [18] moving on the prismatic guide ways in bed [1] provides radial feed for gear [20] through directly coupled ball screw and nut. The axial feed drive or Z-axis [3] moves the wheel head or B-axis [8] up and down. The steady column [11] is mounted on the table slide [18], houses dresser slide [12], dresser head [13] and a vertically mounted hydraulic cylinder. The dresser slide [12] is clamped with the steady column [11] in position through hydraulic clamping arrangement, and moves up and down by piston cylinder arrangement.

The movement of the X – Axis or radial feed drive [10], Z – Axis or axial feed drive [3] and tangential feed drive or Y – Axis [6] is through ball screw and nut, driven by CNC controlled AC servomotor. The X - Axis slide, Z - Axis slide and Dresser slide bears prismatic stick slip free turcite coated guideways for smooth movement and moves on the corresponding prismatic guideways mounted on the column [2], bed [1] and steady column [11] respectively. The vertical slide [4] is suitably balanced for easier movements through counter weight [15] guided by guide rod mounted inside the column [2].

The swiveling grinding head or A-Axis [5] is swiveled through servo controlled worm and worm wheel, rigidly clamped in position through hydraulics. The wheel head or B-axis [8] can be swiveled through A-axis or swiveling grinding head [5] according to the helix angle of the helical gear to be ground. The wheel head slide moves through Y-Axis on the corresponding V guides of the swiveling grinding head or A-axis [5].

The wheel head spindle or B-Axis [8], the direct driven rotary table or C-Axis [9] and dresser head spindle are driven through integral motor. The bearings of the spindles are adjusted both radially and axially, thus controlling the required clearance for the precise running. The dresser slide [12] bears dresser spindle head moves radially along with X-Axis slide. The dresser slide [12] is positioned hydraulically on steady column [11] and mounted horizontally, opposite to the wheel head [8].

According to the preferred embodiment, the bed [1] is made out of stress relieved high grade cast iron and is generously dimensioned and sufficiently ribbed for higher rigidity and vibration damping. It encases mechanical, hydraulic and electrical control units and supports all main units of the machine.

The column [2] is designed as a rigid frame attached to the bed [1]. The Vertical Guideways for the vertical slide [4] are coated with turcite material. The column houses Z axis drive or axial feed drive [3], vertical slide [4] and swiveling grinding head [5]. The left side of the column [2] carries the dog mounting rail. The dogs on this rail actuate the limit switch fixed on the column [2]. The vertical slide [4] is suitably balanced for easier movements through counter weights [15] and which is guided by guide shaft mounted on the column [2].

The vertical slide [4] carries the swiveling grinding head [5] and wheel head [8]. The vertical slide [4], slides over the prismatic guideways of the column and is precisely aligned for better accuracy.
This vertical slide is driven by a precision ball screw and the nut is housed in antifriction needle roller and thrust roller bearings. The ball screw shaft is held vertically and mounted on to the vertical slide [4]. The ball screw nut gets drive from worm shaft and AC Servo motor with holding brake. The motor is mounted inside the main column [2].

The vertical slide movements are restricted by software limits the slide is equipped hardware limit switches. Software limits are with reference to the reference point of axis and hence are active only after referencing. When Emergency stop limit switch gets actuated the feed motion, work spindle rotation, wheel spindle rotation and hydraulic system stop immediately. The ball screw nut and support bearing are automatic lubrication through metering cartridges.

The vertical slide [4] moves vertically on the precision scrapped Guideways of the column [2] to obtain excellent bearing contact with respect to the corresponding prismatic guideways of vertical slide [4]. Precision guide for the vertical slide is obtained by Gib and Guide piece. The maintenance free turcite coated guideways is to give stick slip free movement. The vertical slide [4] travels axially to the work piece to cover the face width of the gear. This axial feed is produced by precision ball screw. The vertical slide houses swiveling grinding head [5]. The vertical slide [4] is suitably balanced for easier movements through counter weights [15] guided by guide shaft. The circular scale & vernier are provided for setting swivel angle.

The swiveling head [5] is hydraulically clamped on face of the vertical slide [4]. The swiveling head [5] pivoted at the center, houses tangential feed drive [6], wheel slide [7] and wheel head [8]. This swiveling head [5] is swiveled by two sets of worm and worm wheel driven by AC Servo motor with holding brake, additionally clamped by 4 pocket hydraulic clamping arrangement.

The tangential feed drive (Y-AXIS) is mounted on the swiveling head [5]. The swiveling head [5] carries the motorized wheel head [8] which is mounted on wheel slide [7].
The wheel slide [7], slides over the swiveling grinding head and is precisely aligned for better accuracy. A servo motor is mounted on the swiveling grinding head [5] which drives the precision ball screw through the timer belt and pulleys for the tangential movement of the wheel head [8]. The ball screw is supported at both ends by precision bearings and these bearings are grease packed for life time. A grease nipple is provided on the grinding slide for lubricating the ball screw and the nut manually. For precise positioning of the slide, a built-in incremental rotary encoder is provided on the Servo motor.

The wheel slide is carried on V guideways, moves transversely on the corresponding V guide ways provided on the swiveling grinding head [5]. The wheel slide [7] along with wheel head [8] is traversed by AC Servo motor coupled to ball screw and nut, torsion resistant metal bellow coupling driven by timing belt and pulley through Y - Axis drive [6]

The wheel head [8] houses the main bearings of the grinding spindle. The bearings are adjusted both radially and axially, thus controlling the required clearance for the precise running of the wheel spindle. The spindle bearings are supplied with grease packed lubrication for life. The wheel spindle is made of high strength alloy steel. The wheel spindle is driven by a direct driven AC spindle motor. The generation of the heat in the wheel head [8] is cooled by the water cooler which supplies the water to the water jacket provided inside wheel head casting structure.

The work table unit is supported on the table slide [18] its prismatic guide ways are lined with Turcite-B lining material and moves over corresponding prismatic guide ways of the bed. This ensures stick slip free movement and better positioning accuracy. The slide movements are restricted by limit switches and trip dogs. The slide is driven through precision ball screw and it is directly coupled with AC servo motor. The ball screw is supported on needle roller and double thrust roller bearing on driver side. Support bearings are grease packed for life time.

The steady column [11] is mounted on table slide [18]. The steady column [11] houses dresser slide [12], dresser head [13] and vertically mounted hydraulic cylinder. The hydraulically operated Dresser slide [12] is clamped in position on steady column [11] through disc spring type hydraulic clamping cylinder. The prismatic Guideways for dresser slide [12] are coated with turcite material. At the operator’s side of the dresser slide [12] carries the dog mounting rail. The dogs on this rail actuate the limit switch fixed on the steady column.

The dresser slide [12] moves vertically on the precision scrapped guideways of the steady column to obtain excellent bearing contact with respect to the corresponding guideways of dresser slide [12]. The precision guide for the dresser slide [12] is obtained by guide piece. The maintenance free turcite coated Guideways is to give stick slip free movement. The dresser slide [12] travels axially to the wheel head [8] for dressing by vertically mounted hydraulic piston cylinder arrangement. The vertical slide [4] houses dresser head [13].

The dresser head [13] houses the main bearings of the dressing spindle. The bearings are adjusted both radially and axially, thus controlling the required clearance for the precise running of the dressing spindle. The spindle bearings are supplied with grease packed lubrication for life. The dresser spindle is made of high strength alloy steel. The dresser spindle is driven by an AC spindle motor. The generation of the heat in the dresser head [13] is cooled by the reciculating type water cooler which supplies the water to the water jacket provided inside the dresser head [13].

According to the preferred embodiment, all the electrical and electronic equipments required for the control of the machine are housed inside the machine mounted electric control cabinet. An operator’s control panel is arranged on a swivel able pendant at the front of the machine.

Dressing and Truing
The purpose of dressing is to restore the original cutting capacity, the “sharpness” of grinding wheel, should that become reduced by embedded particles or dulled grains which is not released from bond. Truing as the term implies, serves to assure the true running of grinding wheel. A multipoint blade type of dresser is fitted at the back of the tailstock with micrometer for precise adjustment dressing diamond. The dressing is accomplished by the interposition X and Z -axes depending on the wheel profile. The dressing diamond is always be rigidity supported to prevent vibration. The diamond has to pass the wheel rapidly for rough stock removal. The wheels may be dressed either wet or dry but the operation should always be carried out under the same conditions as during the actual grinding operation.

The machine also has a table mounted dressing attachment with a blade type of dresser fitted to a swivel able bracket. The angle of swivel can be adjusted depending on the contour of the dressing required.

Mounting of wheel
New grinding wheel is checked for cracks and other damages before they are mounted on flanges. Perfect grinding wheel suspended by a ropes give a clear ringing sound when struck slightly with a small wooden hammer. Being satisfied that the wheel is sound, place one of the blotters usually supplied by the wheel maker on the wheel flange. Slide the wheel on the wheel flange, being careful not to force it, place another blotter on the wheel and slide the clamping flange. Insert the screws. Tighten up one screw until it is snug then go to the diametrically opposite screw and draw it up snug. Then draw up the screw 90° from the others and continue this procedure until all screws are tight but not so tight as to crack the wheel.

Balancing of wheel
Generally, it is sufficient to balance the wheel statically while dynamic balancing is preferred in case of grinding of precision jobs. Before mounting the wheel, it should be perfectly balanced on a balance stand. This can be done by mounting the wheel on the balance mandrel and clamping the wheel on the mandrel with the nut supplied. Place the wheel along with mandrel on to the balancing stand. Balance the wheel with the help of balance weights on the wheel clamping flange. Improper balancing of the wheel results in the poor surface finish and uneven wear of the wheel spindle bearings.

Lubrication of Axis Slides
The antifriction linear reciculating bearings of X-axis and Z-axis are automatically lubricated by oil with the help of centralized lubrication system. Pre-set quantity of oil from the reservoir is fed to the lubrication points of the bearing assemblies at regular intervals which is adjustable with the assistance of timer. The pressure with which the oil is to be fed is preset with the help of a pressure relief valve at our works.
Lubrication of Ball Nut
The pre loaded ball nut of both X and Z slides are also lubricated by oil from separate lines from same oil reservoir meant for guideway lubrication.

Lubrication of Ball Screw support bearings
The ball screw support bearings of both X and Z slides are lubricated with grease for life and hence no maintenance is required. Re-lubrication is necessary in case of major maintenance like dismantling of the ball screw. Care must be taken to use the same type of grease as used for the initial lubrication. Re-lubrication should take place only if the bearings are still worth for operation. Only 20% to 80% of initial grease quantity should be used for relubrication. Re-lubrication should continue until a fresh collar of grease appears at the gap seals such that, old grease must be able to leave the bearing unhindered.

Lubrication of Antifriction bearings of Work Spindle/ Wheel spindle / Dressing Spindle
The work spindle is carefully designed, manufactured and assembled with highest precision antifriction bearings to ultimately yield very high true running accuracy.

These bearings are lubricated by grease for life to minimize wear and to protect the bearings from corrosion. Grease lubrication offers a simplified and cost effective option as the lubricant is more easily retained in the bearing.
Although the invention has been described and illustrated with respect to the exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without parting from the spirit and scope of the present invention.
,CLAIMS:We claim:
1. A gear grinding machine, comprising of:
a bed [1];
a column [2];
an axial feed drive or Z-axis [3];
a vertical slide [4];
a swiveling grinding head or A-Axis [5];
a wheel slide [7];
a direct driven rotary table or C-Axis [9];
a radial feed drive or X-axis [10];
a steady column [11];
a basic rack profile grinding wheel [17];
a table slide [18];
a basic rack profile diamond dresser [19];
a gear [20] and
a controller,
wherein the column [2] with ribs are mounted on the bed [1],
wherein the vertical slide [4] carries the swiveling grinding head or A-axis [5], a wheel head or B-axis [8] and moves on the prismatic guide ways of the column [2],
wherein the work piece or the gear [20] is clamped on the mechanical fixture [14] on the direct driven rotary table or C-axis [9],
wherein the basic rack profile type grinding wheel [17] is dressed by basic rack profile diamond dresser [19] mounted on a dresser slide [12] driven by motor which slides up and down by hydraulic cylinder controlled by limit switches mounted at the front side of the steady column [11],
wherein the direct driven rotary table [9] moving on the prismatic guide ways in bed [1] provides radial feed drive or X-axis [10] through directly coupled ball screw and nut,
wherein the axial feed drive or Z-axis [3] moves the wheel head or B-axis [8] along with vertical slide [8] up and down,
wherein the steady column [11] is mounted on the table slide [18], houses dresser slide [12], dresser head [13] and a vertically mounted hydraulic cylinder,
wherein the dresser slide [12] is clamped with the steady column [11] in position through hydraulic clamping arrangement, and moves up and down by piston cylinder arrangement,
wherein the controller is a Computer Numeric Control (CNC) controller.

2. The gear grinding machine as claimed in claim 1, wherein the basic rack profile type grinding wheel [17] grinds both spur gears and helical gears.
3. The gear grinding machine as claimed in claim 1, wherein a basic rack profile diamond dresser [19] is driven by direct driven dresser spindle.

4. The gear grinding machine as claimed in claim 3, wherein the basic rack profile diamond dresser [19] is changed to obtain different module, pressure angle and with or without root grinding feature.

5. The gear grinding machine as claimed in claim 1, wherein the swiveling grinding head or A-axis [5] mounts the tangential feed drive or Y-axis [6], wheel slide [7] and wheel head or B-axis [8].

6. The gear grinding machine as claimed in claim 1, wherein the grinding operation is carried out by synchronizing wheel head or B-axis [8] and direct driven rotary table or C Axis [9].

7. The gear grinding machine as claimed in claim 1, wherein the wheel head or A-axis [5] is swiveled for the grinding of helical gear.

8. The gear grinding machine as claimed in claim 1, wherein the grinding is done upto the root of the gear [20] by the X axis or radial feed drive [10].

9. The gear grinding machine as claimed in claim 1, wherein the swiveling grinding head [5] is mounted on the vertical slide [4] carries the motorized grinding wheel spindle, and performs swiveling through a worm and worm wheel driven by the motor.

10. The gear grinding machine as claimed in claim 1, wherein the bed [1] is made up of high grade cast iron having prismatic guideways encases mechanical, hydraulic and electrical control units of the gear grinding machine.

11. The gear grinding machine as claimed in claim 1, wherein the column [2] is a rigid frame attached to the bed [1], houses Z axis or axial feed drive [3], a vertical slide [4] and swiveling head [5], and carries a dog mounting rail.

12. The gear grinding machine as claimed in claim 11, wherein the vertical slide [4] is balanced by counter weights [15], run by ball screw and nut and moves vertically on precision scrapped prismatic guide ways on the column [2].

13. The gear grinding machine as claimed in claim12, wherein the precision guide is obtained by a Gib and Guide piece.

14. The gear grinding machine as claimed in claim 1, wherein the grinding wheel spindle and the direct drive rotary table [9], dresser spindle are provided with cooling system.

15. The gear grinding machine as claimed in claim 1, wherein shifting of the basic rack profile type grinding wheel [17] is effected by the ball screw driven by the motor through a timer belt, and pulley during dressing.

16. The gear grinding machine as claimed in claim 1, wherein the column [2], vertical slide [4], radial feed drive or X-axis [10], a steady column [11], and dresser slide [12] are coated with turcite material.