JPS6171955A - Grinding method and its device - Google Patents

Abstract

PURPOSE:To hold the flatness of a grinding wheel within a specific range without requiring interruption of processing by changing the processing point on a work, which is pressed to the grinding wheel being rotated, in accordance with the section form of the wheel, and by arranging so that the mean acting area of the wheel is approx. equal in the radial direction. CONSTITUTION:Tendency of the flatness of a grinding wheel 11 worsening is sensed by preciseness of the current sectional form calculated on the basis of the displacement data from a displacement sensor entered into a calculation control part. That is, if this preciseness of section form is going to exceed a certain allowable limit, the central position of processing is shifted immediately before. The flatness of the grinding wheel 11 can be maintained within a certain preciseness range both because the central position of processing is thus changed and because the grinding action area in the radial direction of wheel 11 is so set as to be constant approximately. Thus there is no need to interrupt the processing just in order to correct the form preciseness of the wheel 11, which will enable automation of processing as well as performance with high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a polishing method and apparatus capable of performing highly accurate planar processing.

[Technical background of the invention and its problems]

For example, when polishing the machined surface (even surface) of a cylindrical workpiece (5) with a protruding boss (5) as shown in FIG. 7, a flat honing device is used as shown in FIG. In this device, a grindstone (Q) fixed to a rotating shaft (S) is rotated upward, and a workpiece W is held by a chuck (to) by a pressure rotating shaft (not shown). is pressed with constant pressure in the direction of arrow P). At this time, the workpiece (B) is forced to rotate (revolution) due to the eccentricity between the axis of the pressurizing rotation shaft and the axis of the chuck.
The whetstone rotates around 00 times, causing a spinning motion.
The planar shape of the whetstone (Q) is transferred onto it.

However, according to the conventional processing method described above, the inside of the whetstone (C) wears more than the outside, and due to this uneven wear, as the frequency of use increases, the whetstone (Q becomes the middle gate and becomes flat) Along with this, the workpiece (W) also gradually becomes convex and its flatness deteriorates.

Therefore, every time the flatness of grinding wheel 0 deteriorates, it is necessary to temporarily stop machining and correct the shape of the grinding wheel (Q).This shape correction work is usually done with a single stone dressing or a ring-shaped correction jig. Therefore, it has the disadvantage of being extremely inefficient.Therefore, this has become a major problem that hinders the automation and rationalization of flat honing processing.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and aims to provide a polishing method and an apparatus therefor capable of stably maintaining the flatness of a grindstone without modifying the surface of the grindstone. .

[Summary of the invention]

In the polishing method of the present invention, in flat honing processing, the polishing surface is rotated and relatively displaced in a plurality of directions arranged so that the polishing surface width in the radial direction passing through the center of rotation is approximately equal.

Further, the polishing apparatus of the present invention includes a processing section that performs flat honing by pressing the workpiece against the grindstone, a measuring section that measures the cross-sectional shape of the polished surface of the workpiece after flat honing, and a measuring section that measures the cross-sectional shape of the polished surface of the workpiece after flat honing. an arithmetic control section that outputs a control signal to the processing section based on the measurement results in the processing section and moves the processing position of the workpiece relative to the grindstone in a direction that improves the flatness of the polishing surface of the grindstone; It is what it is.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

1 and 2 show the polishing apparatus of this embodiment. This polishing device includes a processing section (1) that performs flat honing processing, and a workpiece (1) processed in this processing section (1).
5), and a calculation control section (3) that controls the measurement section (2) and the processing section (1). The processing section (1) includes a plane honing mechanism (4) that performs plane honing, and a workpiece (B) (see Fig. 8 for the shape) that is carried into and out of the plane honing mechanism (4). and a transfer mechanism (5). The planar honing mechanism (4) includes a base (6), a table (3) provided on the base (6) and movable in the direction of the arrow (7), and a motor attached to the table (3). A grindstone rotation drive unit (9) mainly consisting of a diamond drive unit (9), and a base (10a) connected to the upper end of a cylindrical rotating shaft 00 projecting upward from the grindstone rotation drive unit (9). A segment-shaped grindstone made of pellets (see Fig. 3), and a displacement measurement unit 04 attached to the table (3) to detect the amount of displacement of the movable body (8a) of the table (3) in the direction of the arrow (7). , a support 03 fixed to the base (6) and covering the top of the base (6), and this support Q
4 and a pressurizing rotation drive section αψ vertically installed.

The table (3) has a guide support (c) fixed to the base (6) and an arrow (7) at the guide support OI'9.
) direction, a moving body (8a) supported by a moving body (8a), a feed screw αO screwed to the moving body (8a), and a first boob IJ attached to one end of the feed screw Qe. (J'
/), a motor 08 provided at the bottom of the base (6),
The second motor attached to the rotating shaft (18a) of this motor 08
Boo v QcJ and the first and second Boo! JQ71.
It consists of a belt wrapped around Q1). The moving body (8a) is driven in the direction of the arrow (7) by the rotation of the feed screw 0Q due to the rotation of the motor rm transmitted via the belt (a). Further, the displacement measurement unit a3 includes a support stand Cυ fixedly installed on the base (6) adjacent to the guide support 09, and a plurality of support stands Cυ installed in a row along the direction of the arrow (7). (to the limit switch)... These limit switches 4... engage with protrusions (not shown) protruding from the side surface of the moving body (8a), and output a position detection signal indicating the position thereof. . Further, as shown in FIG. 3, the grindstone aυ is composed of (arc-shaped) grindstone pieces (11a). These grindstone pieces (1
1a)... are arranged in equal numbers on three concentric circles around the rotation center A on the base (log): inside, center, and outside. That's right, L7, inside, center part.

The sum of the polishing surfaces of the outer grindstone pieces (11a) is set to be equal. In other words, the grindstone αυ
Even when the workpiece (5) is rotated, the polishing surface area on the workpiece (5) remains approximately the same in the radial direction. In addition,
In this case, the grinding wheel occupancy rate (grinding wheel area/blank surface I★×1
00 changes linearly from the outside to the inside, as shown in FIG. 3 (13).

Furthermore, the pressure rotation drive unit 0ψ is connected to a bearing body (G) attached to the support body 03, a pressure rotation shaft (C) pivotally supported by this bearing body (C), and a bearing body (G). This pressurizing rotation motor (not shown) that rotationally drives the pressurizing rotation shaft ψ, which is folded inwardly, a cylindrical chuck connected to the lower end of this pressurizing rotation shaft 3◆, and a pressurizing A pressurizing device (to) consisting of, for example, a hydraulic cylinder, a pneumatic cylinder, etc., which engages with the upper end of the pivot shaft (c) and is fixed to the support body 03; A cutting depth detection part (26a) that detects the amount of displacement in the axial direction of (c), a cover support wing attached to the bearing body (c), and a pressurizing pivot shaft suspended from this cover support (a). It consists of a cover (2) that surrounds CΦ and the vicinity of the grindstone α, and a nozzle (2) that is provided close to the pressurizing rotation axis (3) and supplies machining liquid to the machining area. Therefore, the axis of the pressurizing rotation shaft (c) and the axis of the rotating shaft 00 are set to be parallel to each other. Further, the pressurizing pivot shaft (c) is rotated by the motor in the direction of the arrow (to), for example, via a spline mechanism, and is pressurized by the pressurizing device in the direction of the arrow 6υ.

Further, the axis of the chuck (c) is not coaxial with the axis of the pressurizing rotation shaft (c), but is eccentrically provided. In addition, the cover support (B) has, for example, a pneumatic cylinder, and the pneumatic cylinder allows the cover to be moved in a timely manner to the arrow (A).
It is designed to move up and down in the direction.

On the other hand, the transfer mechanism (4) transfers the workpiece (5) to the grindstone Q'D.
The loading section (■) that carries the workpiece onto the grindstone α1 (b)
It consists of a measuring section (2), (7) and an unloading section (■) for transporting the water to the draining pro-station (g). Therefore, in the loading section), there is a pedestal (to) placed on the base (6) in close proximity to the table (3), and a loader (b) fixed on this pedestal (to). This loader (A) consists of a main body (to), an arm protruding from this main body (to)), and is attached to the tip of this arm (a) for attaching and detaching the workpiece. It consists of a grip 00 that can be held freely. The axis of the arm (to) is set to be parallel to the direction of arrow (7) and perpendicular to the axis of the rotating shaft 00. The arm is rotatably driven around its axis, and is also driven forward and backward in the axial direction by, for example, a pneumatic cylinder.

Further, the main body (to) is rotatably driven in the direction of arrow 10, and is provided to transfer a workpiece W onto a grindstone Ql from a workpiece stand (not shown).

Further, the unloading section (■) includes a pedestal 03 placed on the base (6) with the table (3) sandwiched therebetween, and facing the loading section (A).
It consists of an unloader (T) fixed on top of this frame (74).This unloader (T) consists of a main body (T), an arm @Q protruding from this main body, and
It consists of a grip OO that is attached to the tip of 6 and detachably grips the workpiece (b). The axis of the arm 4 is set to be orthogonal to the axis of the rotating shaft 00. The bent arm is driven to rotate around its axis, and is also driven forward and backward in the axial direction by, for example, a pneumatic cylinder. Further, the main body @Φ is configured to be driven to rotate in the direction of the arrow @, and is provided so as to transfer the workpiece W from the grindstone (ill) to the water cutter plow station (g). , the measurement unit (2) moves the workpiece W along the arrow (7)
148] transfer mechanism -, a drain pull station (to) installed on the base (6) at the transfer starting point position, and a drain pull station (to) along the transfer mechanism -. ), then the phase determining station 09 installed on the base (6) and the transfer mechanism (g)
This phasing station (G) is followed by the base (
6), and the workpiece (to which the shape measurement has been completed along the transfer mechanism 0 plug), and then the measuring station installed on the base (6)). 5) and a waiting station 6]) for temporarily placing the items. Thus, the transfer mechanism (G) consists of six guide drive bodies installed on the base (6), and three conveyance bodies held by the six guide drive bodies. ing. The guide drive body 2 is adapted to drive the transport bodies □□□... forward and backward in the direction of arrow (7) in a timely manner. Also, the conveyor (to)...
* has a grip part (not shown) for detachably holding the workpiece (b), and is adapted to move the grip part up and down in the direction of arrow 61 at appropriate times. In addition, the draining plow station (2) consists of a mounting table (5) on which the workpiece (5) is placed, a pneumatic cylinder located above the mounting table (2), and a piston of this pneumatic cylinder. to Rondo)! A cover 1571 that covers the mounting table ('i with f') in a timely manner, a nozzle (58a) provided inside this cover 6゛θ that sprays cleaning liquid, and a nozzle (58a) that is also provided inside the cover 67) that sprays air. Nozzle (5
8b). Further, the phase determining station 0→ is used to place the workpiece (5) and rotate it by a predetermined amount. Furthermore, at the measurement station) there is provided a displacement detector consisting of an inverted-shaped support 69 and a plurality of displacement detectors, such as differential transformers, arranged on this support 0 along the direction of the arrow (7). )... and a lifting table 61) on which the workpiece (5) is placed and driven up and down at appropriate times. The measuring element (not shown) of the displacement detector 6) is oriented downward, and the workpiece (5
) is designed to measure the displacement of the machined surface (b). Thus, the arithmetic control section (3) is vertically installed on the support Q1. The calculation control unit (3) has calculation, storage and control functions such as a microcomputer, and electrically connects the displacement detector (to) and the limit switch. It is connected. The processing section (1) and the measuring section (2) are then controlled based on the cannibal program to be described later.

Next, the polishing method of this embodiment will be described based on the polishing apparatus having the above configuration.

First, the principle of the polishing method of this embodiment will be described. The workpiece (
When the axes of 5) are located at six points on the inner circumference side, the inner circumference side of the whetstone αυ wears more, so the cross-sectional shape of the whetstone Qll is such that the inner circumference is closer to the outer circumference as shown in Fig. 4. It has a tendency to become concave, or concave. Conversely, when the axis of the workpiece (5) is at point H on the outer periphery of the surface of the grinding wheel (II), the outer periphery of the grinding wheel will wear more, so the cross-sectional shape of the grinding wheel is shown in Figure 5. As shown, the outer periphery tends to be more crowded than the inner periphery, that is, it tends to be convex. This shows that the cross-sectional shape, that is, the flatness of the grindstone αυ can be controlled by changing the processing center position in the radial direction of the grindstone αυ. That is, when the cross-sectional shape of the whetstone α becomes convex in the center, the processing center position is moved to the inner circumferential side, and conversely, when the cross-sectional shape becomes concave in the center, the processing center position is moved to the outer circumferential side. It becomes possible to maintain the flatness of the polishing surface at a substantially constant level. The present embodiment is thus based on the above principle, and will be described in detail below. First, a workpiece (5) on a workpiece stand (not shown) is gripped by the grip of the loader (2) and transferred onto the grindstone 01. At this time, the movable body (8a) of the table (3) is positioned in advance so that the axis of the workpiece (5) intersects at the point 6Φ of the grindstone 0υ. The point 6ψ is located midway between the points ea and 63. Then, when the pressurizing rotation shaft 3Φ is lowered, the boss (5) of the workpiece W is held by the chuck) and the workpiece W is pressed against the grindstone 0. Next, the grindstone rotation drive unit (9) and the pressure rotation drive unit 04 are activated to rotate the grindstone αυ and the pressure rotation shaft (c). At the same time, lower the cover (A) and
The machining fluid is injected toward the workpiece W from the nozzle (g).

Then, the workpiece (5) undergoes forced rotation (revolution) due to eccentricity between the pressurizing rotation axis C4 and the chuck (6), and the grinding wheel (11
) due to the circumferential speed difference, and the grinding wheel
The planar shape of 1) is transferred. The processing amount at this time is controlled by the cutting amount detection section (26a) or an external timer. After making a certain amount of cut, the series of machining operations described above is stopped, and the pressurizing rotation axis (c) is raised. Next, the processed workpiece (5) is turned over by the unloader (T) and transferred onto the mounting table 0 of the draining plow station (to) with the processed surface (T) facing up. And cover G'? ) is lowered, and the cleaning liquid is sprayed from the nozzle (58a) onto the processing surface (b) of the workpiece (5) for cleaning. Next, the nozzle (58b) injects compressed air to scatter the cleaning liquid adhering to the processing surface (3). Furthermore, the workpiece (b) is transported from the draining pull station (to) to the phase determining station 09 by the transport body of the transfer mechanism.

Then, at this phase determining station a→, the workpiece (5) is rotated by a predetermined angle. As a result, it is possible to prevent erroneous measurements caused by the probes of the displacement detectors OL entering the machined holes at the next measuring station (2).

Incidentally, when a machined hole that causes an erroneous measurement is drilled in the workpiece W, the phase determining station (to) may be skipped. Next, the lifting platform 61 of the measurement station (to) is moved by the conveyance unit (c) to the draining pro-station. The workpiece W is transported to l. And the lifting platform 6υ
is raised, and the machining surface ([t] is brought into contact with the measuring head of the displacement detector 6).
The detection signal indicating the shape of the machined surface is sent to the calculation control section (3
) is output. Next, the lifting table 6υ is lowered, and the workpiece W is transferred to the waiting station 6 by the conveyor. Thus, one cycle of machining is completed. As such machining cycles are repeated, the flatness of the grindstone ov deteriorates as described above. Such a whetstone αυ
The flatness deterioration tendency is detected by the cross-sectional shape accuracy calculated based on the displacement amount data from the displacement detector (g) inputted to the arithmetic and control unit (3). For example, when the obtained cross-sectional shape accuracy is about to exceed the permissible limit as shown in FIG. 6, the processing center position is controlled to be shifted just before that. In other words, as shown by the black circle in Fig. 6, if the workpiece (b) continues to show a tendency to have a convex center, the grinding wheel αυ is in the middle.
Set the table (3
) the position of the moving body (8a) is corrected.

If the machining is continued again in this state, the normal workpiece (5) will gradually show a tendency toward the middle. Therefore, the machining center position is shifted in the opposite direction just before the cross-sectional shape accuracy exceeds the allowable limit. In this case, since the grindstone has a convex shape, the position of the movable body (8a) of the table (3) is corrected so that the processing center position is at point 6a, as shown by the white circle in Figure 6. , such correction of the machining center position using the grindstone Ql) is repeated one after another.

In this way, the flatness of the grinding wheel α can be maintained at a certain level of precision by changing the processing center position and by setting the grinding surface of the grinding wheel αV in the radial direction to be approximately constant. kept within range. Therefore, there is no need to interrupt machining to correct the shape accuracy of the grinding wheel αυ.
Automation and high efficiency of flat honing becomes possible.

In the above embodiment, the number of grindstone pieces (ha)...
The number is the same on the inside, outside, and center, but by decreasing the size and increasing the number toward the outside, the distance between the whetstone pieces (11a) is shortened, and each whetstone piece (lla)
)...It is possible to prevent the workpiece (5) from falling due to the distance between the workpieces (5) being too far apart. Furthermore, the inner whetstone piece (X1a)
In order to reduce the wear of..., the concentration of abrasive grains may be increased toward the inside. Saramura whetstone piece (ha)
The number of concentric circles in which the grinding wheels (11a) are arranged may be set as appropriate, and the grindstone pieces (11a) are not arranged along the concentric circles, but have an average polishing surface area approximately radial. They may be arranged randomly so that they are equal. Furthermore, in the shape of the grindstone piece (xia)..., instead of the transfer mechanism (5) and the transfer mechanism, the workpiece W may be entirely transferred by a robot. Furthermore, the pressurized pivot shaft (
In c), the workpiece (5) may be simply pressed against the grinding wheel α so that only the grinding (self-sharpening) is performed. Furthermore, the processing position of the workpiece (b) may be corrected by directly measuring the cross-sectional shape (b) of the grindstone αD. Furthermore, in the above embodiment, the machining center position is at three points ea
In addition to point settings such as , a3゜so, but,
It is also possible to set outer and inner limit points and to continuously displace them at an arbitrary interval.

Further, in the above embodiment, the processing center position is changed by moving the grinding wheel aD side, but it is also possible to fix the grinding wheel α◇ side and move the workpiece (b).

〔Effect of the invention〕

The polishing method and device of the present invention change the processing position of a workpiece pressed by a rotationally driven grindstone according to the cross-sectional shape of the grindstone, and also change the processing position of the workpiece pressed by a rotationally driven grindstone, and the α9 W of the grindstone... the workpiece.

By making the average polishing surface area approximately equal in the radial direction, the flatness of the grindstone can be maintained within a certain range without interrupting machining. therefore,
High precision is maintained, machining efficiency is significantly improved, and automation is facilitated.

[Brief explanation of the drawing]

Fig. 1 is a front view of a polishing device according to an embodiment of the present invention, Fig. 2 is a plan view thereof, Fig. 3 (5) is an enlarged plan view of the grindstone shown in Fig. 1, and Fig. 3 (g) is A graph showing the grindstone occupancy rate, FIGS. 4 and 5 are explanatory diagrams of a polishing method according to an embodiment of the present invention, and FIG. 6 is a graph showing the relationship between the number of processes and the cross-sectional shape accuracy of the workpiece. FIG. 7 is a perspective view of a workpiece, and FIG. 8 is an explanatory diagram of a conventional plane honing process. (1)...Processing section, (2)...Measuring section, (3)...
・Calculation control unit, (5)...Transfer machine #4 (transport unit), (
3)...table, (9)...grinding wheel rotation drive unit,
0υ...Whetstone, Q41...Pressure rotation drive part (pressure part), ni)...Transfer mechanism (conveyance part), (a) Agent Patent attorney Noriyoshi Kon (and 1 other person) V Ceremony 19 Pledge Reed

Claims (4)

[Claims] (1) It has a planar polishing surface perpendicular to the rotational axis and is formed by a plurality of grindstone pieces, and the grindstone pieces are arranged at positions where the polishing action areas in the radial direction passing through the rotational axis are approximately equal. a method of rotating a polished grindstone; a method of pressing a workpiece against the polishing surface and polishing it with the grindstone; and a method of measuring the cross-sectional shape of the polishing surface of the workpiece or the surface polished by the grindstone. and a method of relatively displacing the processing position of the workpiece with respect to the grindstone in a direction perpendicular to the rotation axis and improving the flatness of the polishing surface based on the cross-sectional shape measurement result. Characteristic polishing method. (2) The polishing method according to claim 1, characterized in that the number of grindstone pieces is increased from the inside to the outside. (3) A polishing device characterized by having the following configuration. (a) A grindstone having a planar polishing surface, a grindstone rotation drive section that holds this grindstone and rotates the grindstone around a rotational axis perpendicular to the polishing surface, and a grindstone rotation drive section that It consists of a table supported so as to be movable forward and backward in a direction perpendicular to the axis of rotation, and a processing section that holds a workpiece and presses it against the polishing surface, and the grindstone is formed of a plurality of pieces of the grindstone, and the grindstone is formed of a plurality of pieces of the grindstone. denotes a processing section arranged at a position where the polishing action areas in the radial direction passing through the center of rotation of the grindstone are approximately equal. (b) A measurement unit that measures the cross-sectional shape of the surface polished by the grindstone of the workpiece polished in the processing unit and converts it into an electrical signal. (c) A transport unit that transports the workpiece before polishing onto the grindstone and transports the workpiece after polishing to the measurement unit. (d) Based on the electrical signal output from the measuring section, a control signal is sent to the processing section to move the table in a direction that improves the flatness of the polishing surface so that the processing position of the workpiece relative to the grindstone is improved. Arithmetic control unit that outputs. (4) The polishing device according to claim 3, wherein the number of grindstone pieces increases from the inside to the outside.