JPH06155300A - Superhigh speed grinding method and device therefor - Google Patents

Abstract

PURPOSE:To provide a grinding method or a grinding device for obtaining the sufficient grinding efficiency and life of a grinding wheel in the superhigh speed grinding. CONSTITUTION:A grinding liquid is jetted under high pressure from the first nozzle 38 towards the grinding surface of a grinding wheel 14 and the ground point K of ground member 26, and since the intrusion of an air layer which is formed on the grinding surface and revolves together with the grinding surface, into the grinding pint K is suppressed by a shielding plate 50 arranged on the upstream side from the grinding point K on the grinding surface, the shortage of the grinding liquid at the grinding point K is improved, and the grinding efficiency or the life of the grinding wheel in the superhigh speed grinding can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-high speed grinding method and apparatus for grinding a work material while rotating a grinding wheel at an ultra high speed.

[0002]

2. Description of the Related Art When grinding a work material with a grinding wheel, it is theoretically said that the peripheral speed of the grinding wheel should be increased in order to increase the grinding efficiency or extend the life of the grinding wheel, that is, the dressing interval. . However, in reality, when the peripheral speed of the grinding wheel is increased, the grinding fluid is not sufficiently supplied between the grinding wheel and the work material, so that the grinding efficiency or the wheel life cannot be extended theoretically. For this reason, the conventional grinding method or grinding apparatus usually uses a peripheral speed of about 30 m / sec, and even a so-called high-speed grinding uses a peripheral speed of about 45 to 60 m / sec. It stayed.

[0003]

Therefore, in the conventional grinding method or grinding apparatus described above, sufficient grinding efficiency or grindstone life cannot be obtained yet. That is, an object of the present invention is to provide a grinding method or a grinding apparatus which can obtain sufficient grinding efficiency or grinding wheel life in ultra-high speed grinding.

[0004]

[Means for Solving the Problem] The inventors of the present invention have conducted various studies on the basis of the above circumstances, and as a result, when the peripheral speed of the grinding wheel becomes ultra-high-speed grinding of 100 m / sec or more, the grinding wheel Based on the hypothesis that the grinding fluid is insufficient at the grinding point between the grinding surface of the grinding wheel and the work material, the air layer formed on the surface of the grinding wheel and rotating with the surface scatters the grinding fluid. In order to reduce the air layer that penetrates into the grinding fluid as much as possible, a shielding plate is provided on the upstream side of the grinding point, resulting in good grinding results even when the rotation speed of the grinding wheel is much higher than before. It was found that The present invention was made based on such findings.

That is, the gist of the grinding method of the present invention is an ultra-high speed grinding method for grinding a work material while rotating the grinding wheel at an ultra-high speed. While injecting the grinding liquid at a high pressure toward the grinding point with the work material, by using the shielding plate arranged on the upstream side of the grinding point on the grinding surface of the grinding wheel,
It is to block an air film formed on the grinding surface and entering together with the grinding surface toward the grinding point.

[0006]

With this configuration, the grinding fluid is jetted at a high pressure toward the grinding point between the grinding surface of the grinding wheel and the workpiece, while the grinding surface is higher than the grinding point. The shielding plate arranged on the upstream side prevents the air layer formed on the grinding surface and rotating with the grinding surface from entering the grinding point, so that the shortage of the grinding liquid at the grinding point is improved and The damage of the cutting edge is reduced and the grinding efficiency is increased or the life of the grindstone is further increased.

[0007]

A second object of the present invention is to provide an ultra-high-speed grinding apparatus for grinding a work material while rotating a grinding wheel at an ultra-high speed. 1)
A high-pressure injection nozzle that injects a grinding liquid at a high pressure toward a grinding point between the grinding surface of the grinding wheel and the work material, and (2) a position upstream of the cutting point of the grinding surface of the grinding wheel. And a shielding plate arranged in the state of being close to the grinding surface.

[0008]

With this configuration, the high-pressure jet nozzle jets the grinding liquid at a high pressure toward the grinding point between the grinding surface of the grinding wheel and the work material, while the high-pressure jet nozzle of the grinding surface An air layer that is formed on the grinding surface and rotates with the grinding surface is moved to the grinding point by the shield plate that is placed close to the grinding surface when the position is fixed in a state of being in contact with the position upstream of the grinding point. Since the entry is prevented, the shortage of the grinding liquid at the grinding point is improved, the damage of the cutting edge of the abrasive material is reduced, the grinding efficiency is enhanced, or the life of the grindstone is further obtained.

Here, it is preferable to use an automatic position adjusting device for automatically adjusting the position of the shielding plate so that the shielding plate is in a state of substantially contacting the grinding surface.
By doing so, the position of the shielding plate is optimally maintained regardless of wear of the grinding surface of the grinding wheel.

Preferably, a second high-pressure jet nozzle for jetting the grinding liquid at a high pressure is further provided toward a position on the grinding surface upstream of the shielding plate. By doing so, there is an advantage that sparks are prevented from wrapping around the grinding surface and the life of the grinding wheel is further extended.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A detailed description will be given below of an embodiment of the present invention with reference to the drawings.

FIG. 1 shows the structure of the main part of a cylindrical grinding machine. In the figure, a grindstone shaft 1 provided on a grindstone headstock 10
Reference numeral 2 denotes a grindstone shaft 1 which is rotationally driven at a superhigh speed in a direction indicated by an arrow by a drive motor (not shown).
The grinding wheel 14 is fixed to the end of 2 by a mounting device 16. The grinding wheel 14 and the mounting device 16
Has mechanical strength, dynamic balance, dimensional accuracy, etc. that can sufficiently withstand ultra-high speed rotation at a peripheral speed of about 100 to 200 m / sec.

The grinding wheel 14 has a circular core member 20.
And a segment tip 22 attached to the outer peripheral surface of the core member 20. The core member 20 has a material strength and shape sufficient to withstand centrifugal force during ultra-high speed grinding, and is made of, for example, steel or CFRP. In addition, the segment tip 22
For example, superabrasive grains such as diamond and CBN are resinoid bond, vitrified bond, metal bond,
It is a grindstone joined by electrodeposition.

The work material 26 is provided with a cylindrical outer peripheral surface to be ground, and as is well known, a center shaft of a tailstock center and a headstock center (not shown) is used. It is rotatably supported around the headstock, and is rotated in the direction indicated by the arrow from the headstock through the key. In the present embodiment, the rotation center axes of the work material 26 are located at the same height as that of the grinding wheel 14 and are parallel to each other.

Below the grinding wheel 14 and the work material 26, there is a pedestal 30 for receiving the grinding fluid falling from them.
The grinding fluid collected by the pedestal 30 is returned to the grinding fluid pressure feeding device 32. The grinding fluid pressure-feeding device 32 includes a filtering device (not shown) for purifying the refluxed grinding fluid, and two high-pressure pumps (not shown) that pressure-feed the grinding fluid that has passed through the filtering device. The grinding fluid is pressure-fed to the first nozzle 38 and the second nozzle 40 via 36, respectively. The first nozzle 38 is supplied with a super-high pressure grinding liquid of, for example, about 200 kg / cm ² , and the second nozzle 40 is supplied with a high-pressure grinding liquid of, for example, about 80 kg / cm ² .

The first nozzle 38 is horizontally projected from the grinding wheel headstock 10 so as to inject the grinding liquid toward the grinding point K which is the contact point between the grinding wheel 14 and the work material 26. The second nozzle 40 is attached to the bracket 41 of the first convex portion 39, and the second nozzle 40 is a portion of the grinding surface which is the outer peripheral surface of the grinding wheel and is located on the upstream side of the grinding point K. In terms of the central angle, the grinding wheel headstock 10 is horizontally projected so that the grinding fluid is sprayed to a portion located on the upstream side about 120 degrees in a direction substantially perpendicular to the tangent line of the portion. It is attached to the second convex portion 43.

As shown in detail in FIGS. 2 and 3, the first
The nozzle 38 is provided with a slit 46 formed so as to penetrate the front end surface 44 of the main body 42 that has a wedge shape as a whole. The slit 46 is set to have a width of 0.15 mm, a length of 9 mm, and a through sectional area of 1.35 mm ² so that the pressure of the grinding liquid pumped by the grinding liquid pumping device 32 does not decrease. An injection pressure of 55 to 10 kg / cm ² can be obtained at a position 3 to 15 mm apart from 46. The length of the slit 46 is set to be equal to or larger than the grinding width of the grinding surface. With the above-described configuration of the slit 46, the grinding liquid ejected by the first nozzle 38 has a discharge speed equal to or higher than the speed of the air layer formed on the grinding surface of the grinding wheel 14 and moving with it.

Then, as shown in FIG.
Grinding surface K, that is, the first nozzle 38
A shield plate 50 is fixed to the grindstone headstock 10 so as to come into contact with a portion located upstream of the grinding wheel 14 by a predetermined distance, or about 30 degrees in terms of the rotation center angle of the grinding wheel 14. The shielding plate 50 is made of, for example, cast iron, and as shown in detail in FIG. 4, is integrally formed of a contact portion 52 that contacts the grinding wheel 14 and a base portion 54 that forms an angle of about 120 degrees with respect to the contact portion 52. The contact portion 52 is mounted in a direction toward the center of rotation of the grinding wheel 14. The base portion 54 of the shield plate 50 is held by the shield plate position adjusting device 56, and the contact state of the contact portion 52 is automatically adjusted.

The shielding plate position adjusting device 56 is provided in the third convex portion 45 which is independently protruded in the horizontal direction between the first convex portion 39 and the second convex portion 43 in the grindstone headstock 10. A pair of guide rods 58 fixed to the third convex portion 45, a movable member 60 guided thereby in a direction substantially parallel to the contact portion 52, and the movable member 6
A spring 61 for increasing the positional accuracy of the shield plate 50 by urging 0 in one direction and a pulse motor 64 with a speed reducer having a screw shaft 62 screwed to the movable member 60 as an output shaft are provided. . This pulse motor with reduction gear 6
4 is controlled by the control device 68 shown in FIG.

In FIG. 5, the vibration sensor 70 is fixed to the shield plate 50 or the movable member 60, and the contact portion 52 is used to determine the contact state of the shield plate 50 with the grinding wheel 14.
The vibration generated by the sliding contact between the grinding wheel 14 and the grinding wheel 14 is detected. The setter 72 supplies to the controller 74 the first reference signal SJ1 and the second reference signal SJ2 larger than the preset first reference signal SJ1 for determining the magnitude of the vibration signal SV from the vibration sensor 70. The controller 74 drives the pulse motor 64 with a reduction gear so that the vibration signal SV from the vibration sensor 70 is between the first reference signal SJ1 and the second reference signal SJ2, and the position of the shield plate 50 with respect to the grinding wheel 14 is adjusted. Adjust. Thereby, the shielding plate 50
Is always kept in very slight contact with the grinding wheel 14.

As described above, according to the present embodiment, the grinding fluid is jetted at high pressure from the first nozzle 38 toward the grinding point K between the grinding surface of the grinding wheel 14 and the work material 26. The shielding plate 50 disposed on the upstream side of the grinding point K on the grinding surface prevents an air layer formed on the grinding surface and rotating with the grinding surface from entering the grinding point K. The shortage of the grinding liquid in step 1 is improved, and grinding efficiency or grindstone life can be obtained in ultra-high speed grinding.

Further, according to the present embodiment, since the grinding liquid is jetted at a high pressure from the second nozzle 40 toward the position upstream of the shield plate 50 on the grinding surface, the spark on the grinding surface of the grinding wheel 14 is sparked. Is prevented, the life of the grinding wheel 14 is further extended, and the air layer formed on the grinding surface is destroyed by the injection from the second nozzle 40,
There is an advantage that the formation amount of the air layer reaching the shield plate 50 is suppressed.

FIGS. 6, 7, and 8 show the results of experiments conducted under the following grinding and dressing conditions in order to confirm the effects of the grinding apparatus of the above-described embodiment. In each figure, ⋄ indicates the case where the shield plate 50 is substantially in contact with the above embodiment, and □ indicates a gap between the shield plate 50 and the outer peripheral grinding surface of the grinding wheel 14 of 0.2 mm. In this case, a ♦ mark indicates a case where the gap between the shielding plate 50 and the outer peripheral grinding surface of the grinding wheel 14 is 0.5 mm, and a ○ mark indicates a case where only the first nozzle 38 ejects without using the shielding plate 50. ing.

[Grinding conditions] Machine used: Ultra-high speed cylindrical grinder Grinding stone: CB80M200VN1 (380 × 9 × 8
0) Work material: SCM435 (60φ × 5t) Grinding method: Wet cylinder plunge grinding Peripheral speed ratio: 100 Grinding efficiency: 20mm ³ / mm ・ s S ・ O ： 20rev Grinding oil ： Soluble type (× 50)

[Dressing Conditions] Method: Traverse Rotary Dressing Dresser: Wheel Dresser (110φ × U1, SD4
Wheel peripheral speed: 80 m / sec Dresser peripheral speed: 20 m / sec Peripheral speed ratio: 1/4 (down cut) Lead: 0.05 nn / row Depth of cut: φ4 μm / pass

As is clear from the above experimental results, when the shield plate 50 is brought into substantially contact with the outer peripheral grinding surface of the grinding wheel 14 (marked with ⋄), only the injection of the first nozzle 38 is used (marked with ◯). Although the power consumption is slightly increased, the amount of wear of the grindstone is ⅓, and the dressing interval is tripled. Alternatively, in the grinding apparatus of the present embodiment, the grinding efficiency can be significantly increased by increasing the cutting depth unless the same dressing interval as the conventional one is used.

As is clear from the above experimental results,
The gap between the shield plate 50 and the outer peripheral grinding surface of the grinding wheel 14 is set to 0.
When it is set to 5 mm (marked with ◆), there is no particular difference as compared with the case where only the injection of the first nozzle 38 is used (marked with ○),
The gap between the shield plate 50 and the outer peripheral grinding surface of the grinding wheel 14 is set to 0.
When it is set to 2 mm (square mark), compared with the case where only the injection of the first nozzle 38 is used (◯ mark), the temporary effect that the abrasion amount of the grindstone is small and the dressing interval is long is recognized. That is, by setting the gap between the shield plate 50 and the outer peripheral grinding surface of the grinding wheel 14 to 0.2 mm or less, the grinding efficiency or the grinding wheel life in ultra-high speed grinding is improved.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other modes.

For example, in the above-described embodiment, the shield plate 50 is controlled by the control device 68 shown in FIG.
However, the control device 68 may repeatedly perform position control at a predetermined period for a control period of a certain ratio. In this way, there is an advantage that the shielding plate 50 is pressed against the grinding wheel 14 for a short period of time and abrasion of the shielding plate 50 is suppressed.

The shield plate 50 may be controlled by the control device 68 shown in FIG. 5 only during the low speed rotation period of the grinding wheel 14 prior to the start of grinding, and thereafter fixed at that position. By doing so, when the core member 20 of the grinding wheel 14 is made of steel, the diameter is slightly increased by about 10 to 60 μm due to centrifugal force or the like as the rotation speed becomes about 200 m / sec. In the ultra-high speed grinding state, the contact state between the grinding wheel 14 and the shielding plate 50 is maintained, and the shielding plate 50 is compared with the case where the control is performed continuously.
There is an advantage that the wear of is suppressed.

Further, in the shielding plate position adjusting device 56 of the above-mentioned embodiment, the position of the shielding plate 50 is adjusted by the screw shaft 62 driven by the pulse motor 64 with a reduction gear, but it is rotated by the motor. The position may be adjusted by a cam that is moved, or the position may be adjusted by a fluid actuator such as a hydraulic cylinder.

Further, the shielding plate 50 of the above-mentioned embodiment is made of cast iron which is hard to adhere to the ground surface, but is made of a material which is easily ground, for example, a carbon plate or a hard resin such as a thermosetting resin. It does not matter if you In such a case, there is an advantage that a spark does not occur due to the contact of the shielding plate 50 and the abrasion of the grinding surface of the grinding wheel 50 does not occur.

Further, in the above-described embodiment, the first nozzle 38
Although the grinding fluid was sprayed from the above at a pressure of 200 kg / cm ² , the air layer on the grinding surface toward the grinding point K is blocked by the action of the shielding plate 50, so that the first nozzle 38 does not necessarily have such a condition. It does not have to be injected at a high pressure of about 200 kg / cm ² .

Further, the second nozzle 40 of the above-mentioned embodiment is
Although it was mounted so as to spray from the direction perpendicular to the grinding surface of the grinding wheel 14, it may be mounted so as to spray obliquely toward the upstream side in the rotational direction.
In this case, the jetting direction opposes the moving direction of the air layer on the grinding surface, so that there is an advantage that the air layer is efficiently removed.

Further, instead of the pulse motor 64 of the above-mentioned embodiment, a DC or AC driven servo motor may be used. Further, instead of the vibration sensor 70 of the above-described embodiment, an AE sensor or a detection device that detects the contact state of the shield plate 50 based on an increase in the drive current of the motor that drives the shield plate 50 may be used. .

Further, in the above-mentioned embodiment, it does not matter that the grinding liquid ejecting apparatus other than the first nozzle 38 and the second nozzle 40 is provided as needed.

[0037]

[Brief description of drawings]

FIG. 1 is a diagram illustrating a main part of a cylindrical grinding machine to which a grinding method of the present invention is applied.

FIG. 2 is an enlarged view showing the first nozzle of the embodiment of FIG. 1 with a part thereof cut away.

FIG. 3 is a bottom view showing a slit formed on an end surface of the first nozzle of FIG.

FIG. 4 is a plan view of a main part showing a contact state of a shielding plate with a grinding wheel in the embodiment of FIG.

5 is a block diagram illustrating a circuit configuration of a control device that controls the shield plate position adjusting device in FIG. 1. FIG.

FIG. 6 is a diagram showing wear characteristics of a grinding wheel in the grinding method shown in FIG. 1 in comparison with a case where only a first nozzle is used.

FIG. 7 is a diagram showing a surface roughness change characteristic of a grinding wheel in the grinding method shown in FIG. 1 in comparison with a case where only a first nozzle is used.

FIG. 8 is a diagram showing a power consumption value during grinding in the grinding method shown in FIG. 1 in comparison with a case where only the first nozzle is used.

[Explanation of symbols]

 14: Grinding whetstone 38: 1st nozzle (high-pressure injection nozzle) 40: 2nd nozzle (2nd high-pressure injection nozzle) 50: Shielding plate

Claims (4)

[Claims] 1. A super high speed grinding method for grinding a work material while rotating a grinding wheel at a super high speed, wherein a grinding liquid is directed toward a grinding point between the grinding surface of the grinding grindstone and the work material. While spraying at a high pressure, by using a shield plate arranged at a position upstream of the grinding point on the grinding surface of the grinding wheel, the shielding plate is formed on the grinding surface and moves toward the grinding point together with the grinding surface. An ultra-high-speed grinding method characterized by blocking an air film that enters. 2. An ultra-high speed grinding apparatus for grinding a work material while rotating a grinding wheel at a super high speed, wherein a grinding liquid is directed toward a grinding point between the grinding surface of the grinding wheel and the work material. A high-pressure jet nozzle for jetting at a high pressure, and a shield plate arranged in a state of being close to the grinding surface at a position upstream of the work point of the grinding surface of the grinding wheel, High speed grinding machine. 3. The ultra-high speed grinding apparatus according to claim 2, further comprising an automatic position adjusting device that automatically adjusts the position of the shielding plate so as to substantially contact the grinding surface of the shielding plate. . 4. A second high-pressure injection nozzle for preventing sparks from being entrained on the grinding surface by injecting a grinding fluid at a high pressure toward a position on the grinding surface upstream of the shielding plate. 2 ultra high speed grinding machine.