JPS587427B2 - Grinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a grinding machine using a grinding wheel whose abrasive grains are hard materials such as cubic boron nitride. It is efficient truing and dressing.

In a conventional grinding machine that uses a grinding wheel with cubic boron nitride abrasive grains, a tool stand supporting a truing wheel is mounted on the opposite side of the workpiece with the grinding wheel sandwiched between the tool stand and the tool stand. The grinding wheel is trued by moving the table forward toward the grinding wheel and traversing it in a direction parallel to the axis of the grinding wheel.

However, due to space constraints, it was not possible to make the mechanism for advancing and traversing the tool stand sufficiently rigid, which resulted in slight deflection on the grinding surface of the grinding wheel's outer periphery after truing. There was a problem.

A grinding wheel that uses cubic boron nitride as its abrasive grains has a layer of abrasive grains fixed to the outer periphery of a metal deck, and the grinding wheel itself has high rigidity, so even the slightest deflection on the outer grinding surface quickly grows due to the grinding resistance. This immediately makes grinding impossible.

Therefore, there has been a strong demand for truing such a grinding wheel without any runout.

In addition, recently, in order to dress a grinding wheel, a dressing song wheel having a front surface that is rearwardly limited by a predetermined amount from the front surface of the truing wheel was advanced at the same time as the truing wheel by the same amount, and the truing wheel was trued with the truing wheel. Later, a device was developed to dress the grinding wheel by supplying loose granules for dressing between the dressing wheel and the grinding wheel. The amount of retraction of the front of the dressing car with respect to the front of the car increases as truing and dressing are repeated, and the distance between the grinding surface on the outer periphery of the grinding wheel and the front of the dressing car after truing is not constant, which may result in unstable dressing accuracy. there were.

The present invention has been made to solve this problem, and includes supporting a truing tool along with a workpiece support device and a dressing tool on a table that is relatively moved in a direction parallel to the grinding surface of a grinding wheel. A support stand is mounted on a grinding wheel head, and the support stand is advanced toward the grinding wheel to perform correction grinding of the dressing tool, and during dressing, loose particles for dressing are supplied between the grinding surface of the grinding wheel and the dressing tool. The gist of this is to

Embodiments of the present invention will be described below based on the drawings.

1 is a bed, and on this bed 1, a grindstone head 2 is a workpiece W.
It is placed so that it can move forward and backward toward the

This grinding wheel head 2 has a grinding wheel 3 in which abrasive grains of hard material such as cubic boron nitride are fixed in layers on the outer peripheral surface of a metal disk, and is rotatable around an axis perpendicular to the advancing and retreating direction of the grinding wheel head 2. This grinding wheel 3 is rotatably driven by a motor 4 fixed on the grinding wheel head 2 via a pulley and a belt.

Reference numeral 5 denotes a grinding wheel cover fixed to the side surface of the grinding wheel head 2 to cover the grinding wheel 3 and a dressing wheel 20, which will be described later. The structure is such that only the portion facing the workpiece W is exposed.

The grinding wheel 3 uses a hard material such as cubic boron nitride as the abrasive grains, which causes little wear and little change in its outer diameter. Unlike the grinding wheel cover that covers the grinding wheel, a front cover whose position is adjusted as the grinding wheel diameter decreases is not provided.

Reference numeral 6 denotes a coolant nozzle attached to the front upper part of the grindstone cover 5, and the coolant nozzle 6 is connected to a coolant liquid supply device (not shown) to supply coolant liquid to the grinding point during the grinding process.

Next, the feed device 7 for moving the grindstone head 2 forward and backward toward the workpiece W will be explained. A feed screw shaft 8 is rotatably supported on the bed 1, and A nut 9 is screwed together.

A servo motor 10 is fixed to the bed 1, and the servo motor 10 rotates the feed screw shaft 8 in forward and reverse directions to move the grindstone head 2 forward and backward toward the workpiece W.

A table 11 is placed on the bed 1 so as to be slidable in a direction perpendicular to the advancing and retreating direction of the grinding wheel head 2, in other words, in a direction parallel to the outer peripheral grinding surface of the grinding wheel 3, and is used as a traverse device. It is connected to the cylinder device 12.

13 is a workpiece support device provided on the table 11;
This workpiece support device 13 is configured to rotate and drive the workpiece W by sandwiching it between both centers.A base 14 is fixed to the table 11 in line with the workpiece support device 13 in the moving direction of the table 11. A tool stand 15 is placed on this base 14 so that its position can be adjusted in a direction parallel to the advancing and retreating direction of the grindstone head 2.

A truing wheel 16 is rotatably supported on the tool stand 15 around an axis parallel to the moving direction of the table 11, and this truing wheel 16 is rotated in the same direction as the grinding wheel 3 by a motor 17 fixed on the tool stand 15. Rotation driven heather.

The truing wheel 16 is made of a metal disc with diamond particles fixed in a layer on the outer periphery, and its width is made smaller than the width of the grinding wheel 3 in order to reduce tooling resistance.

A base 13 holds the grinding wheel 3 on the grinding wheel head 2 and holds the workpiece W.
A support stand 19 is mounted on the base 18 so as to be movable forward and backward toward the outer peripheral grinding surface of the grinding wheel 3.

The bearing part 29 of the support stand 19 enters into the whetstone cover 5 through a window hole 30 made in the whetstone cover 5, and this bearing part 2
A dressing wheel 20 is rotatably supported at 9 so as to face the grinding wheel 3, and the dressing wheel 20 is driven to rotate in the opposite direction to the grinding wheel 3 by a motor 21 fixed on the support base 19.

The dressing wheel 20 is made of a material having a certain degree of hardness, toughness, and wear resistance, such as tempered steel or hardened steel, and its width is approximately the same as the width of the grinding wheel 3.

Next, the feed applying device 22 that moves the support stand 19 forward and backward toward the grinding wheel 3 will be explained. The supplied feed nut 24 is screwed together,
Ratchet wheels 25 and 26 are keyed to the rear end.

A cylinder device 27.28 is fixed to the base 18, and a piston rod 31.32 of this cylinder device 27.28 is fixed to the base 18.
The claws 33 and 34 pivoted at the tips are compressed springs 35,
36 and is removably engaged with ratchet wheels 25 and 26.

The position where the pawls 33 and 34 start to engage with the pawl wheels 25 and 26 is adjusted appropriately by baffle plates 37 and 38, and when the pawl 33 is reciprocated by the operation of the cylinder device 27, the screw shaft 23 is moved between the pawl wheels 25 and 26. The support base 19 is rotated forward by an amount F
When the pawl 34 is reciprocated by the operation of the cylinder device 28, the screw shaft 23 is reversed via the ratchet wheel 26, and the support base 19 is limited to the rear by a retraction amount B which is smaller than the advancement amount F. ing.

39 is an upward nozzle fixed to the base 18, and this nozzle 39 enters into the grinding wheel cover 5 through the window hole 30 to supply dressing liquid between the grinding wheel 3 and the dressing wheel 20 from below. It is connected via a pump P to a tank 40 in which a dressing liquid is stored.

As an example, the dressing liquid is one in which 500 g of dressing free particles 41 (diameter about 100 μm) such as alumina, silicon carbide, etc. are mixed in 10 liters of the grinding liquid.

Reference numeral 42 denotes an agitating blade which prevents separation of the grinding fluid and loose particles, and is rotationally driven by a motor 60.

Next, a re-truing device 43 for extending the life of the grinding wheel 3, that is, the interval between truing and dressing, by lightly truing the grinding wheel 3 that has been trued and dressed by the truing wheel 16 and the dressing wheel 20 will be explained.

A sliding rod 47 is fitted into a guide stand 45 fixed to the upper surface of the grinding wheel cover 5 via a bracket 44 so as to be able to move forward and backward in a direction parallel to the rotational axis of the grinding wheel 3.
A piston 48 fixed to the rear end of the sliding rod 47 is fitted into a cylinder 49 fixed to the guide base 45.

A holding member 5 integrally fixed to the tip of the sliding rod 47
0, the feed shaft 51 is prevented from rotating and is fitted to be slidable in a direction perpendicular to the rotational axis of the grinding wheel 3, and a screw shaft 52 supported on the holding member 50 is screwed onto the feed shaft 51. ing.

53 is a knob fixed to the rear end of the screw shaft 52.

A plate spring 54 as an elastic means is fixed to the tip of the feed shaft 51 and extends in the horizontal direction, and a truing tool 55 is fixed to the free end of the plate spring 54 above the rotational axis of the grinding wheel 3. ing.

The lower corner of this truing tool 55 has a chamfer 56.
56 is applied so that the truing tool 55 can ride on the outer peripheral grinding surface of the grinding wheel 3.

As the truing tool 55, diamond particles sintered with a copper-tin alloy are used.

Next, the operation of the above embodiment will be explained.

In a normal grinding cycle, when the push button switch PB1 is pressed after the workpiece W is attached to the workpiece support device 13, the rotation of the servo motor 10 is controlled based on a command from the control device 56, and as a result, the grinding wheel head 2 The workpiece W is ground by the grinding wheel 3 while being reciprocated by a certain amount.

When the cutting quality of the grinding wheel 3 deteriorates due to repetition of such grinding cycles, the grinding wheel 3 is subjected to truing and dressing.

When the push button switch PB2 is pressed for this purpose, the cylinder device 27 is activated and the screw shaft 23 is moved between the pawl 33 and the ratchet wheel 25.
The support base 19 is advanced by a forward amount F, and the dressing wheel 20 is corrected and ground by a correction amount S by the grinding wheel 3 (see FIG. 6).

Next, the cylinder device 28 is operated and the screw shaft 23 is moved to the pawl 34,
The rotation is reversed via the ratchet wheel 26, and the support base 19 is retreated by a retreat amount B.

Subsequently, the table 11 is moved to the left in FIG. 1 by the cylinder device 12 to the truing position, and the truing wheel 16 is positioned slightly to the left of the grinding wheel 3.

When the table 11 is indexed to the truing position, the servo motor 10 is rotated forward based on a command from the control device 56, the grinding wheel head 2 is advanced by a predetermined amount, and the grinding wheel 3 is moved by a truing amount T relative to the truing wheel 16. cut into.

The next motor 17 is started, the truing wheel 16 is rotated in the same direction as the grinding wheel 3, coolant liquid is ejected from the coolant nozzle 6, and the table 11 is rotated to the cylinder device 12.
The grinding wheel 3 is moved to the right and the outer peripheral grinding surface of the grinding wheel 3 is shaped and removed by the truing amount T by the truing wheel 16.

In this case, the table 11 is placed directly on the bed 1 and is moved with high rigidity and high precision, so that the outer peripheral grinding surface of the grinding wheel 3 is trued with extremely high precision without any runout.

After the above-mentioned truing, a gap D of about 50 μ, which is the sum of the retreat amount B of the support base 19 and the truing amount T, is formed between the grinding wheel 3 and the dressing wheel 20.

Subsequently, the motor 21 is started, the dressing wheel 20 is rotated in the opposite direction to the grinding wheel 3, and the pump P is driven by the motor M, so that the dressing liquid is supplied from the nozzle 39 to the gap D.
is supplied from below.

The loose particles 41 in the dressing liquid supplied to the gap D are backed up by the dressing wheel 20 and then transferred to the grinding wheel 3.
The grinding wheel 3 is dressed by biting into the bond holding the abrasive grains and scraping them off, making the abrasive grains protrude from the bond and dressing the grinding wheel 3.

When the timer in the control device 56 times out after the set time has elapsed, the motors 21 and M are stopped and the dressing is completed.

When the dressing is finished, pressure oil is supplied to and discharged from the cylinder 49, the sliding rod 47 is reciprocated, and the truing tool 5
5 is traversed while being elastically pressed against the outer grinding surface of the grinding wheel 3 by the repulsive force of the leaf spring 54, and the outer grinding surface of the grinding wheel 3 is re-trued by the truing tool 55.

As a result, the abrasive grains of the grinding wheel 3 that were damaged by the loose grains 41 or lifted from the bond during the previous dressing are corrected and shaped.

To adjust the depth of cut of the truing tool 55 in this re-truing, the screw shaft 52 is rotated by the knob 53 to adjust the position of the feed shaft 51, and the plate that presses the truing tool 55 against the outer peripheral grinding surface of the grinding wheel 3 Adjust the repulsive force of the spring 54.

In the above embodiment, the dressing wheel 20 is corrected and ground before being trued by the truing wheel 16, but the corrective grinding of the dressing wheel 20 may be performed immediately after the grinding wheel 3 is re-trued by the truing tool 55. .

Furthermore, after the correction grinding of the draining wheel 20, the support stand 19 does not necessarily need to be moved back by the amount of retreat B;
If the grinding wheel 3 and the dressing wheel 20 are not retreated, a gap of the truing amount T will be formed between the grinding wheel 3 and the dressing wheel 20 after truing.

Further, in the above embodiment, the truing tool 55 is connected to the leaf spring 5.
As shown in FIG. This truing tool 155 is movably fitted.
may be pressed against the outer peripheral grinding surface of the grinding wheel 3 by a compression spring 154 having a relatively long spring constant and a small spring constant.156 is a stop member fixed to the grinding wheel cover 5, and the sliding rod 47 is located at the retreating end. Truing tool 15
When the truing tool 155 leaves the outer peripheral grinding surface of the grinding wheel 3, the truing tool 155 rides on this stop member 156, and its forward movement is restricted.

In this case, the truing tool is cubic boron nitride,
It is possible to use a suitable rod-shaped material made of a material with little wear such as ceramic or cemented carbide.

As described in detail above, according to the present invention, a tool stand for supporting a truing tool is mounted on a table that is relatively moved in a direction parallel to the grinding surface of a grinding wheel, in line with a workpiece support device, and A support stand that supports the dressing tool is installed so that it can move forward and backward toward the grinding surface of the grinding wheel, and this support stand is moved forward toward the grinding wheel to perform correction grinding of the dressing tool, and during dressing, the dressing tool is connected to the grinding surface of the grinding wheel. Since loose granules for dressing are supplied between the tool and the tool, the truing tool can be traversed with high precision by the highly rigid table, and the grinding wheel grinding surface can be kept in a highly accurate state without runout. Can be trued.

Furthermore, since the dressing tool is subjected to correction grinding, the distance between the grinding wheel grinding surface and the dressing tool can always be kept constant, and dressing can be performed stably and with high precision.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a grinding machine according to the present invention, FIG. 2 is an enlarged partial cross-sectional view of FIG. An enlarged cross-sectional view, Figure 4 is a ■-■ cross-sectional view of Figure 3, Figure 5 is an enlarged cross-sectional view of Figure 2,
FIG. 6 is a diagram showing the positional relationship between the dressing wheel and the grinding wheel, and FIG. 7 is a diagram showing another embodiment of the re-truing device. 1...Intermediate, 2...Whetstone stand, 3...
... Grinding wheel, 7 ... Feeding device, 11 ...
... Table, 12 ... Cylinder device (traverse device), 13 ... Workpiece support device, 15
......Tool stand, 16...Truing car (Truing tool), 19...Support stand, 20
・・・・・・Dressing car (dressing tool), 2
2... Feeding device, 39... Nozzle, 40... Tank, 41... Loose particles for dressing, W... Working thing.

Claims (1)

[Claims] 1. A grinding wheel head that supports a grinding wheel whose abrasive grains are made of hard material such as cubic boron nitride and is moved relatively toward a workpiece on a bed by a feeding device, and a workpiece support device that supports the workpiece. a table to which is mounted and relatively moved in a direction parallel to the grinding surface of the grinding wheel on the bed by a traverse device, and a truing tool arranged parallel to the table in the direction of relative movement of the workpiece support device and the table. a tool stand for supporting the dressing tool; a support stand mounted on the grindstone head so as to be freely advanced toward the grinding surface of the grinding wheel and supporting a dreving tool facing the grinding surface of the grinding wheel; Preferably, the present invention is equipped with a feeding device that advances the support stand toward the grinding surface of the grinding wheel, and a device that supplies loose particles for dressing between the grinding surface of the grinding wheel and the dressing tool during dressing. A grinding machine featuring: