JPS584356A - Apparatus for truing grinding wheel - Google Patents

Abstract

PURPOSE:To provide the titled apparatus, wherein a roll for detecting contact is provided adjacent to a truing wheel, the contact is detected by the change of tone on the roll outer circumferential surface with the roll abutted on the grinding wheel outer circumferential surface so that using this position as a reference the cutting amount of the truing wheel is precisely controlled. CONSTITUTION:In a case the grinding wheel G is trued, an electromagnetic opening-closing valve 37 is opened to apply a black paint in a container 40 to the whole outer circumferential surface of the contact detecting roll 31. Then the roll 31 that is being rotated is moved to the left per pulse together with the truing wheel provided in parallel with the roll 31. When the fact that the roll 31 has become in contact with the grinding wheel G is detcted by a tone judging circuit 43 connected to a light receiver 42, since the roll 31 is moved with the truing wheel to the left by a set cutting amount, the roll 31 is ground by that amount by the grinding wheel. Then the truing wheel is moved in a direction of the rotational axis, and the grinding wheel G is ground by the set cutting amount.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a grinding wheel truing device that can apply a predetermined amount of cut to a grinding wheel using abrasive grains of a hard material such as cubic boron nitride.

In general, so-called on-grinding wheels that use hard materials such as cubic boron nitride as abrasive grains are extremely expensive, so during truing, the depth of cut of the truing process should be kept to the minimum necessary to remove the waviness of the grinding wheel. Therefore, it is necessary to extend the life of the grinding wheel as long as possible, but conversely, if the depth of cut is too small, the waviness of the grinding surface cannot be completely removed, which poses a problem that affects grinding accuracy.

Therefore, in such a truing device, it is necessary to control the depth of cut of the truing wheel with a degree of accuracy, but in reality, the grinding wheel expands thermally due to changes in air temperature, bearing temperature, etc. In addition to the position of the machined surface changing, the grinding wheel causes minute wear due to grinding, and this wear is not always constant. It is necessary to cut with the truing wheel based on the position of the grinding surface.

For this reason, conventionally, a contact detection bar is provided at a position adjacent to the truing wheel, which is aligned on the outer circumferential surfaces of the truing wheel and the grinding wheel after truing. Conventionally, a vibration detector detects that the contact detection par has contacted the grinding wheel, and the cutting depth of the truing wheel is controlled based on this position. In this case, it is necessary to distinguish between the following motion caused by the grinding wheel scattering and the vibration caused when the wheel comes into contact with the grinding wheel, and there is a problem in that the contact detection circuit becomes complicated.

In other words, the base disc of a general ('BN grinding wheel) is made of aluminum with a large coefficient of thermal expansion, and the outer diameter of the grinding wheel changes minutely due to changes in the humidity of the base disc. Coolant is constantly supplied,
This is accelerated by the high speed rotation of the grinding wheel and scattered onto the contact detection bar. Therefore, even when the contact detection bar does not contact the grinding wheel, the contact detection bar vibrates, and the strength of this vibration also changes depending on the amount of coolant supplied.

In addition, prior to truing, paint is applied to the outer circumferential surface of the truing wheel, and when the truing wheel comes into contact with the grinding wheel, it is detected that a part of the applied paint has been cut off by a change in the brightness of the outer circumferential surface of the truing wheel. A method has been proposed in which the truing wheel cuts a certain amount based on this position, but the truing wheel has many diamond grains closely attached to the roll surface, and the surface is not flat but has many recesses. Therefore, even when the truing wheel comes into contact with the grinding wheel, the paint applied to the outer circumferential surface of the truing wheel is not completely removed. The conventional method for detecting this has a problem in that it cannot be reliably determined that the truing wheel has contacted the grinding wheel.

The present invention was made in view of these conventional problems, and an object of the present invention is to accurately control the cutting depth of a truing wheel without being affected by the coolant supplied to the outer peripheral surface of the grinding wheel. The feature is that a roll for contact detection is rotatably supported at a position adjacent to the truing wheel of a movable body that supports the truing wheel, and during truing, paint is applied to the outer peripheral surface of the roll for contact detection. At the same time as coating, the contact detection roll is brought into contact with the outer peripheral surface of the grinding wheel by moving the movable body, the contact is detected by a change in brightness of the outer peripheral surface of the contact detection roll, and the position where this contact is detected is taken as a reference. The reason is that the depth of cut of the truing wheel is controlled.

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

In FIG. 1, reference numeral 10 denotes a bed of a grinding machine, and a grindstone head 11 is mounted on this bed rad 10 so as to be able to move forward and backward toward the workpiece W, and is moved forward and backward by a servo motor 2 and a known screw feeding mechanism. It has become so. The grinding wheel G is rotatably supported on the grinding wheel head 11, and is an OBN grinding wheel in which hard abrasive grains made of cubic boron nitrate are fixed in layers on the outer peripheral surface of an aluminum disk. It is rotated by an installed grindstone drive motor (not shown). Note that 13 is a grinding wheel cover that covers the grinding wheel G.

In addition, a truing device 15 is provided at the rear of the upper surface of the grindstone head 11.
A traverse body 17 is slidably guided on the support base 16 in a horizontal direction parallel to the grinding surface of the grinding wheel G, and as shown in FIG. It is designed to be reciprocated by a traverse cylinder 18 fixed to. On the upper part of this traverse body 17, a movable body 20 faces the axis of the grinding wheel G and is movably guided along a guide surface slightly inclined forward, and a servo motor fixed to the traverse body 17 is mounted. 21, the feed screw 22, and the nut 23.
is moved forward and backward toward the axis of At the right end of the movable body 2o in Figure 2, a protrusion 20a that protrudes toward the processing surface of the grinding wheel G is rotated by a drive motor 25 fixed to the right side of the protrusion 20a. A support shaft 26a is supported parallel to the grinding surface of the grinding wheel G.
A truing wheel 26 is fixed to the tip portion protruding from the left side surface of the protrusion 20a.

The truing wheel 26 is made by fixing diamond grains in a layer to the outer peripheral surface of an iron disc, and its width is smaller than the width of the grinding surface of the grinding wheel G in order to reduce truing resistance.

On the other hand, a movable shaft 27 is fitted to the left end of the movable body 2o, allowing only axial movement along an axis parallel to the moving direction of the movable body 20, and a servo motor 28 fixed to the movable body 2o The shaft is moved by a feed screw 29 which is rotated thereby.

A roller 31 for contact detection is mounted on the right side of a protrusion 30a extending toward the grinding surface of the grinding wheel G of the bracket 30 fixed to the tip of the movable shaft 27, at a predetermined distance from the truing wheel 26. The truing wheel 26 is supported rotatably around an axis parallel to the rotational axis of the truing wheel 26, and is rotationally driven by a motor 33 when applying paint. Note that when the traverse body 17 is located at the rightward end, the contact detection roll 3
1 faces the grinding surface of the grinding wheel G, and when the traverse body 17 moves to the left end, the truing wheel 26 faces the grinding surface of the grinding wheel G.
The traverse end is adjusted to move to the left side of the

Further, a truer cover 34 that covers the truing wheel 26 and the contact detection roll 31 is fixed to the left side surface of the protrusion 20a of the movable body 2o.
4. At a position facing the contact detection roll 31 on the top surface, a third
As shown in the figure, a spray nozzle 35 for spraying black paint is attached to the outer peripheral surface of the contact detection roll 31. This spray nozzle 35 has a /churi 36 and an electromagnetic on/off valve 37.
A branch pipe 38 is connected to a source of pressurized air via a venturi 36 and has one end opening into a venturi 36 and the other end opening into a paint container 40 containing black liquid paint. Therefore, when the electromagnetic on-off valve 37 is opened by the energization of the solenoid 5QLA and processing air is supplied to the spray nozzle 35, the liquid paint in the paint container 4o is sucked out by the venturi 36 and is ejected from the spray nozzle 35 together with the air. The contact detection roll 31 is rotated by the drive of the motor 33.
Sprayed uniformly onto the outer circumferential surface of the

Further, at a position on the rear wall of the truer cover 34 facing the outer peripheral surface of the contact detection roll 31, a projector 41 for irradiating a light beam onto the outer peripheral surface of the contact detection roll 31 and a contact detection roll 3 are provided.
1 A light/dark discrimination circuit 4 is attached with a light receiver 42 for detecting reflected light from the outer circumferential surface, and a signal outputted from the light receiver 42 is supplied to a light/dark discrimination circuit 43.
3, depending on the intensity of the reflected light, the paint may remain on the irradiated part of the outer peripheral surface of the contact detection roll 31, or the paint may be removed due to contact between the contact detection roll 31 and the grinding wheel G. This circuit determines whether the paint has been removed and outputs a contact detection signal when the paint has been removed, and is comprised of a known comparison circuit or the like. In addition, the floodlight 41
An air nozzle 45 fixedly installed at the top of the screen forms an air curtain on the front surfaces of the emitter 41 and receiver 42 when applying paint to prevent paint from adhering to the front surfaces of the emitter and receiver 41,42. , the electromagnetic on-off valve 3 via the connecting pipe 4s
7 and the venturi 36.

The circuit shown in FIG. 4 is a control circuit for processing a workpiece in a predetermined grinding cycle and for truing the grinding wheel G using the truing device configured as described above.
The arithmetic processing unit 50 is composed of a microprocessor or the like. Connected to the arithmetic processing unit 50 is a memory 51 that stores a program for executing the truing cycle shown in FIG. 5 in addition to a machine program for executing the workpiece machining cycle.

The memory 51 also stores control parameters such as the depth of cut T of the truing wheel 31 required in the truing cycle, and the interface 52
A data input device 5 connected to the arithmetic processing unit 50 via
3, the control parameters are written. The interface 52 is also connected to the output of the bright/dark determining circuit 43, so that a contact detection signal output from the bright/dark determining circuit 43 is provided to the arithmetic processing unit 50.

On the other hand, the arithmetic processing unit 50 includes drive units DUX, which respectively drive the servo motors 12.21°28.
D.U.V.

The DUW is connected via an interface 55, and command pulses are distributed to the drive units (DUX, DUV, DUW) to rotate the servo motors 12 to 28 by an amount corresponding to the number of distributed pulses. Further, a hydraulic control circuit 56 that controls the supply of pressure oil to the traverse cylinder 18 is connected to this interface 55 .

Furthermore, from Inter7Ace57, solenoid SQL
A control signal for instructing energization or de-energization of the motor 25, 33 and the motor 25, 33 is output and applied to the high-voltage circuit of the circuit.

Next, the operation of the truing device having the above configuration will be explained.

When the sharpness of the grinding wheel G deteriorates due to repeated grinding cycles, the control of the truing cycle shown in No. 5 A is started after the grinding wheel head 11 is returned to the processing origin. first,
In preparation for truing, a process of applying paint to the contact detection roll 31 is performed in step (1). That is, in this step (1), after energizing the motor 33 to rotate the contact detection roll 31, the solenoid SQL
A is energized for a certain period of time, the electromagnetic on-off valve 37 is opened while the contact detection roll 31 rotates one rotation or more, and black paint is applied to the entire outer peripheral surface of the contact detection roll 31.

When the application of the paint is completed in this way, the process moves from step (1) to step (ii).
One designated pulse is distributed to the V-axis (drive unit corresponding to the control axis that controls the movement of the movable body 20) to the DUV. After that, the process moves to step (iii), and it is determined whether or not the contact detection roll 31 has contacted the grinding surface of the grinding wheel G based on the output of the bright/dark discrimination circuit 43. If it is determined that the grinding surface of the grinding wheel G is in contact, the process moves from step (iii) to step (jy), and if it is determined that the grinding surface is not in contact, the process returns to step (ii) and the command pulse is sent to the v-axis again. distribute.

At the start of truing, the trunnion cross body 17 is located at the rightward end as shown in FIG. 2, and the contact detection roll 31 is opposed to the grinding surface of the grinding wheel G as shown in FIG. In addition, the position of the tip of the contact detection roll 31 was aligned on the tip of the truing wheel 26 and the outer circumferential line of the grinding wheel G during the previous truing, as will be described later. Once the command pulse is distributed,
The contact detection roll 31 comes into contact with the grinding surface of the grinding wheel G, and at the same time, the tip of the truing wheel s6 becomes aligned with the grinding surface of the grinding wheel G.

In this way, when the contact detection roll 31 contacts the grinding surface of the grinding wheel G and moves from step (iii) to step (z), the number of command normals corresponding to the set depth of cut T is distributed to the V axis, and the movable The body 2o is advanced toward the grinding wheel G by the cutting depth T. As a result, the contact detection roll 31 is ground by the grinding wheel G, and the tip of the contact detection roll 31 is
As shown in Q), the position is moved back by the depth of cut T.

When the cutting operation is completed in this way, step (fy
) to step (V), and after rotating the truing vehicle by the biasing force 2≦ of the motor 25, a command is given to the hydraulic control circuit 56 to operate the traverse cylinder 18, and the traverse body 17 is moved to the leftward end. move it to. As a result, the truing wheel 26 moves to the left side of the grinding wheel G, as shown in FIG.
Truing of the grinding surface of grinding wheel G is completed.

Then, when moving to step (vi), a number of command pulses corresponding to the corrected feed amount F, which is larger than the depth of cut T by a predetermined amount, are distributed to the W axis corresponding to the movement of the movable shaft 27, and contact is made. The detection roll 31 is advanced by the corrected feed amount F (
Figure 6(e)). Thereafter, in the second step, the traverse cylinder 18 is operated in this state to move the traverse body 17 to the rightward end.

As a result, the contact detection roll 31 is corrected and ground by the grinding wheel G after truing, and as a result, the truing wheel 2
6 and the tip of the contact detection roll 31 are aligned on the outer circumferential line of the grinding wheel G.

Furthermore, when the corrective grinding of the contact detection roll 31 is completed in this way, the steps from step (vlii) to step (vlii)
After the rotation of the motor 25.33 is stopped, a number of backward command pulses corresponding to a fixed set backward scale are distributed to the V-axis, and as shown in FIG. 6(g), the contact detection roll 31
The truing cycle is completed by moving the grinding wheel G away from the grinding surface by the set retraction scale.

As described above, in the present invention, a roll for contact detection is rotatably supported adjacent to the truing wheel on a movable body that pivotally supports the truing wheel, and during truing, the roll for contact detection is rotatably supported. After coating the outer peripheral surface of the roll, the contact detection roll is moved toward the outer peripheral surface of the grinding wheel by moving the movable base, and the contact detection detects that the contact detection roll has contacted the outer peripheral surface of the grinding wheel. The contact detection roll is detected by changes in the brightness of the outer circumferential surface of the grinding wheel, and the cut of the truing wheel is controlled based on this.When the contact detection roll comes into contact with the outer circumferential surface of the grinding wheel, the The paint applied to the grinding wheel is reliably removed, and the brightness of the contact detection roll's outer surface changes significantly, making it possible to reliably detect that the contact detection roll has contacted the grinding wheel's outer surface. By making the cut with the truing wheel, it is not affected by the thermal expansion of the grinding wheel, etc.
It has the advantage of allowing highly accurate cutting.

In addition, even if the contact detection member vibrates due to the supply of coolant, it is not affected at all, so compared to a method that detects contact of the contact detection member with the outer peripheral surface of the grinding wheel by vibration of the contact detection member, the coolant It has the advantage of being less susceptible.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a partially sectional side view of a grinding machine equipped with a truing device;
Figure 2 is a cross-sectional view taken along the line ■-■ in Figure 1, Figure 3 is a cross-sectional view taken along the line ■-■ in Figure 2, and Figure 4 is a cross-sectional view taken along the line ■-■ in Figure 2.
The figure shows a control device that controls the feeding of the grinding wheel head and the truing head, Fig. 5 is a flowchart showing the operation of the arithmetic processing unit 50 of Fig. 4, and Fig. 6 shows the grinding wheel and truing wheel showing the truing cycle. This is a relationship diagram. 11... Grindstone head, 15... Truing device, '
16... Support heath, 17... Traverse body, 18
...Traverse cylinder, 20...Movable body, 21
... Servo motor for cutting, 25.33 ... Drive motor, 26 ... Truing wheel, 27 ... Movable axis, 2
8... Correction feed servo motor, 31... Contact detection roll, 35... Spray nozzle, 36... Venturi, 38... Branch pipe, 40... Paint container, 41... Fist.
Emitter, 42... receiver, 43... light/dark discrimination circuit,
5o... Arithmetic processing unit, -51... Memory, 52, 5
5.57... Inter 7 Eighth, 56... Hydraulic control circuit, DUX, DUV, DUW... Drive unit, G fist... Grinding wheel. Patent applicant Toyota Machinery Co., Ltd.

Claims (1)

[Claims] (1) A truing wheel is mounted on a movable body that is movable relative to a grinding wheel whose abrasive grains are made of a hard material such as cubic boron nitride in a direction parallel to the grinding surface of the grinding wheel and in a direction crossing this. A truing device for truing the grinding wheel by relatively moving the movable body in a direction parallel to the grinding surface, wherein the movable body is substantially parallel to the rotation axis of the truing wheel at a position adjacent to the truing wheel. a virtual contact detection roll that is rotatably supported around an axis; a coating device that applies a coloring agent such as paint to the outer peripheral surface of the contact detection roll prior to truing of the grinding wheel by the truing wheel; and the contact detection roll. a bright/dark discrimination circuit that detects contact between the contact detection roller and the grinding wheel by determining brightness or darkness of the outer peripheral surface of the roll; and a relative movement of the movable body to move the contact detection roll toward the outer peripheral surface of the grinding wheel. At the same time, the movement is stopped based on the contact detection by the light/dark discriminating device, and the movement of the movable base is controlled based on the position when this contact is detected, so that the truing wheel is moved relative to the grinding surface. A truing device for a grinding wheel, characterized in that it is provided with a feed device that applies a certain amount of cut.