JP2000084852A - Dressing device for grinding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dressing device for grinding machines, by which high precision dressing can be done in a short time by complementing defects of both a rotary dresser and a NC dresser. SOLUTION: A rotary deresser 21 which is provided with a rotary wheel 25 which is turned around an axis in the same direction as the axis of a work W to roughly dress the peripheral edge of a grinding wheel 17, is provided at a main spindle 3 or a feed table 7, for example, of a male screw grinding machine for grinding a bar-like work W. Further, a NC dresser 23 in which a single dressing stone-dressing tool provided with a diamond on the tip of a handle part is inclinably supported around a rotary shaft crossing the axis of the grinding wheel 17 at right angles to finish dress the peripheral edge of the grinding wheel 17, is provided at the main spindle 3 or the feed table 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dressing apparatus for a grinder for forming a grindstone used for a grinder or the like into a desired shape, and more particularly to a dressing work for a grindstone required at the time of changing a set or replacing a grindstone. The present invention relates to a technology for efficiently and accurately performing the process.

[0002]

2. Description of the Related Art For example, a male screw formed on a screw shaft of a ball screw is first cut into a screw shape, and is then ground by a grinding machine. For this screw grinding, for example, a single-thread screw grinding wheel can be used. In this case, the grindstone has a disk shape and its peripheral edge is formed in a shape corresponding to the thread groove. Then, traverse grinding in which the grindstone is moved in the feed direction in accordance with the advance of the thread accompanying the rotation of the work is performed by the grinder. That is, in the traverse grinding, the outer periphery of the work is helically ground along the screw by the rotational movement of the grindstone, the rotational movement of the work, and the reciprocating movement of the work in the axial direction.

Conventionally, dresses such as a curved shape of a grindstone mounted on such a grinding machine include, for example, a rotary dress,
Or an NC dress was used. The rotary dress is a rotary dresser in which diamonds are densely embedded on the outer periphery, and transfers the shape of the dresser to the grindstone by pressing the dresser and the grindstone against each other. In this rotary dress, a plurality of different transfer shapes can be formed on the rotary foil, and the shape change can be completed in a short time because it is a plunge cut. On the other hand, the NC dress uses a single stone dressing tool in which diamond having a sharp tip is attached to a shank. In this NC dress, the shape change can be flexibly dealt with by changing the control program of the NC program device for controlling the relative position of the single-stone dress tool with respect to the grindstone.

[0004]

However, although the above-mentioned rotary dress can respond to a shape change in a short time, it is often necessary to change the rotary wheel when changing a grindstone or changing a set. It is necessary to keep a selection of rotary wheels, and there is a problem that an increase in the amount of work leads to an increase in cost. The dress accuracy of the rotary dress is NC
There was a disadvantage that it was inferior to a dress. On the other hand, the NC dress is capable of high-precision dressing and can flexibly respond to shape changes, but it takes a long time to dress because of single point turning, and wear of the diamond portion at the tip advances rapidly, When the amount is large, there is a disadvantage that an error easily occurs in the shape at the start of the dress and at the end of the dress. The present invention has been made in view of the above circumstances, and provides a dressing apparatus for a grinding machine that enables high-accuracy dressing in a short time by mutually complementing disadvantages of both a rotary dress and an NC dress. The purpose is to do.

[0005]

In order to achieve the above object, a dressing apparatus for a grinding machine according to the present invention comprises a feed table movable in the axial direction of a main shaft for rotating a work, and a feed table orthogonal to the axial direction of the main shaft. A whetstone cutting table movable in the direction, a whetstone spindle fixedly mounted on the whetstone cutting table, and a whetstone spindle for driving a disk-shaped whetstone mounted with the axial direction as a rotation axis, and provided on the feed table side. ,
A rotary dress for rotating a rotary wheel having at least one row of dressing circumferential grooves formed on an outer peripheral surface thereof around an axis parallel to an axis of the grinding wheel to roughly dress a peripheral portion of the grinding wheel; An NC dress that is provided on the side and has a sharp-edged single-stone dressing tool that is tiltably held around an axis perpendicular to the axis of the whetstone to finish dress the periphery of the whetstone, and a dress of the whetstone And an NC program device for controlling the operation of the work.

[0006] In this dressing machine for a grinding machine, when a large amount of initial dresses are required at the time of replacement of a grindstone or at the time of setting change, the dressing can be performed at a stretch to a shape close to a required shape by a rotary dress. Thereafter, the finishing dress is performed with high precision by the NC dress. Therefore, since the dress amount by the NC dress is small, the dress time is shortened,
The amount of wear at the tip of the single-stone dress tool can be reduced. As a result, it is possible to dress with high accuracy in a short time,
The predetermined dress shape can be maintained for a long time.

In the dressing apparatus for a grinding machine, it is preferable that the rotary wheel includes a plurality of rows of dress grooves having different shapes.

In this dressing machine for a grinding machine, a rough dress can be performed stepwise by sequentially pressing a grindstone against each dress groove of the rotary wheel, so that the dress amount per one dress groove is reduced. In addition to extending the life of the rotary wheel, dressing can be performed efficiently.

Further, in the dressing machine for a grinding machine, it is preferable that the rotary wheel has a dressing shape including a side dress surface of a grindstone.

In this dressing apparatus for a grinding machine, when a grindstone is dressed to a shape close to a required shape by a rotary dress, a side dress is performed at the same time, and a single-stone dress tool is used for finishing dressing with an NC dress. Interference,
Grinding of parts other than the grooves during work processing is avoided.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a dressing apparatus for a grinding machine according to the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a plan view of a dressing device for a grinding machine according to the present invention. The dressing apparatus 1 for a grinding machine according to the present invention can be suitably applied to, for example, an external thread grinding machine in which the set is frequently changed. Therefore, a dressing machine for a grinder applied to a male screw grinder will be described below as an example. Spindle 3 of external thread grinder
Is provided with a chuck 5 for gripping the work W, and the bar-shaped work W is rotated by the spindle 3 via the chuck 5.

The main shaft 3 is fixed to the feed table 7, and is movable with respect to the bed 9 in the axial direction of the main shaft 3 (hereinafter referred to as "X direction") by a moving mechanism (not shown). The work W is moved in the X direction together with the main shaft 3 by moving the feed table 7.

On the other hand, the bed 9 has a whetstone cutting table 11
Is provided. The grindstone cutting table 11 has a bed 9
In contrast, a moving mechanism (not shown) is movable in a direction orthogonal to the X-axis direction (hereinafter, referred to as “Y direction”). A grindstone spindle 15 having a drive shaft 13a set parallel to the center axis of the workpiece W is provided on the grindstone cutting table 11.
Is fixed. The drive shaft 13 of the grinding wheel spindle 15
A disk-shaped grindstone 17 is mounted on a.

With such a male screw grinding mechanism, the rotation of the work W by the main shaft 3, the reciprocating movement of the work W in the X direction by the feed table 7, the grinding wheel spindle 1
The traverse grinding for spirally grinding the outer periphery of the work W can be performed by the rotation of the grindstone 17 by 5 and the reciprocating movement of the grindstone cutting table 11 in the Y direction.

The amount of movement of the feed table 7 and the grindstone cutting table 11 is detected by position detecting means provided at a part of the sliding portion with the bed 9.
As this position detecting means, for example, a linear scale such as a magnetic scale is suitably used. The linear scale detects the displacement by detecting the displacement from an electric signal obtained by moving the magnetic detection head on a scale provided with a magnetic scale. Thus, the position can be detected simply and with high accuracy.

The external thread grinder has a rotary dress 21 for dressing the grindstone 17 and a NC dress 23 for finishing dresses. The rotary dress 21 and the NC dress 23 are arranged side by side on the grinding wheel 17 side of the main shaft 3 in the feed direction of the feed table 7. In the present embodiment, the rotary dress 2
1 and the NC dress 23 are provided on the side surface of the main shaft 3,
For example, the rotary dress 21 and the NC dress 23 may be directly fixed to the feed table 7. That is, it is only necessary that the dress position can be selected with respect to the grindstone 17 by moving the feed table 7 in the X-axis direction.

First, the configuration of the rotary dress 21 will be described. FIG. 2 is an enlarged view of a main part of the rotary dress, and FIG. 3 is a partially enlarged view of FIG. The rotary dress 21 rotates the rotary wheel 25 having a disk-shaped peripheral surface formed in a desired groove shape, and rotates the grindstone 17 to the rotary wheel 2.
The dressing of the grindstone 17 is performed by pressing against the groove 5. As shown in FIG. 2, a plurality of (in this example, three rows) dressing circumferential grooves 27 a, 27 b, and 27 c having a substantially V-shaped cross section are formed in the rotary wheel 25 of the rotary dress 21. Each groove is formed with a curved surface having a slope θ (an angle formed with the Y axis) for side cutting and a radius R for forming a groove on the work. That is, each groove 27a, 27b,
27c, the groove inner wall is formed at the inclination angles θ1, θ2, θ3, and a curved surface having a radius of R1, R2, R3 is formed at the groove bottom. This inclination angle θ and radius R
Is the relationship of θ1>θ2> θ3, R1>R2> R3,
It is formed such that the angle and radius gradually change in the direction in which the grooves are arranged. Incidentally, abrasive grains such as diamonds are planted on the surface of the groove.

The groove opening of each groove is set to be larger than the width of the grindstone 17, and the curved surface at the bottom of each groove is formed to form a shape (for example, a gothic arch shape) formed on the side surface of the grindstone 17. It is formed in a required shape (that is, a shape including a dress allowance). The grindstone 17 is formed by the rotary dress 21 having the rotary wheel 25 having such a shape.
When dressing, the grindstone 17 is placed in each groove 27a, 27b, 2
7c in a stepwise manner. Here, FIG.
As shown in the figure, the case where the peripheral edge of the grindstone 17 is inserted into one groove of the rotary wheel 25 is considered. By sending (cutting) the grindstone 17 to the rotary wheel 25 side, first, the corner 17a of the periphery of the grindstone 17 is removed by the groove inner wall of the angle θ, and the side cut is gradually formed. When the cutting is further advanced, a semicircular portion 17b in which a curved surface having a radius R of the groove bottom is transferred to the tip of the grindstone 17 is formed. In this way, the grindstone 17 is roughly dressed in a shape to which the shape of the inner wall 29 of the rotary wheel has been transferred. The side cut can prevent interference of a tool at the time of NC dressing, which will be described later, and can prevent grinding of a portion other than a groove at the time of thread groove processing of a work.

The rotary dress 21 in the present embodiment
Are three shallow, medium, and deep grooves 27a, 27 having different shapes.
b, 27c, and rough dressing is completed by inserting the grindstone 17 in the order of shallow, middle, and deep grooves. Therefore, the shape of the deep groove is closest to the desired groove shape. However, the present invention is not limited to this procedure, and an appropriate change may be made, such as starting the dress from the middle groove 27b or skipping from a shallow groove to a deep groove, depending on the desired groove shape and whetstone material. As described above, in the rotary dress 21, the dress of the grindstone 17 is gradually changed in the grooves 27a, 27b,
By performing the process by 7c, a rough dress having a relatively large amount of dress can be performed at a high speed, and abrasion of the rotary wheel can be reduced because the rough dress is in contact with the grindstone 17 by a line or a surface. In addition, by performing coarse dress step by step,
The dressing time per groove can be shortened, and the life of the rotary wheel 25 can be secured longer.

The rotary dress 21 serves as a rough dress in the dressing process of the grindstone 17 as described above. After this rough dress, the dress dressing of the grindstone 17 is performed by the NC dress 23 described later.

Next, the configuration of the NC dress 23 will be described.
FIG. 4 is a view taken in the direction of the arrows AA in FIG. 1 and shows a main configuration of the NC dress 23. According to FIG. 4, a handle portion 31 provided with a single-stone single-stone dressing tool 35 at the tip is fixed to a central portion of a U-shaped support frame 37, and both arm portions 37a of the support frame are provided with a handle. The shaft 39 is fixed to a shaft 39 which is orthogonal to the portion 31 and is rotatably supported by a bearing 41. The shaft 39 is driven to rotate by a turning motor 43 (hereinafter, this rotation direction is referred to as a “ψ direction”).

In this embodiment, the shaft 39 is arranged in a direction perpendicular to the plane of FIG. 1 (hereinafter, referred to as "Z direction"). In the NC dress 23, it is preferable that the shaft 39 is disposed in the Z-axis direction, but the present invention is not limited to this. The shaft 39 may be disposed in any direction perpendicular to the X-axis, that is, on the circumferential surface of the grindstone 17. What is necessary is just to be arrange | positioned in the direction parallel to a tangent line.

The single-stone dressing tool 35 is rotated by the shaft 39 in the ψ direction, moved by the feed table 7 in the X direction, and moved by the grindstone cutting table 11 in the Y direction.
As shown in FIG. 5, the tip of the single-stone dress tool 35 is a whetstone 1
7 can be moved according to the curved surface shape or the Gothic arch shape. As a result, as shown in FIG. 6, the semicircular portion 17b formed at the tip of the side dress 17c surface of the grindstone 17 by the coarse dress is formed into a gothic arch shape 17e shown as an example by removing the hatched portion 17d. Is done. The rotation in the ψ direction and the movement in the X and Y directions at this time are performed based on a command from an NC program device described later. An arbitrary dress command (program) can be input to the NC program device, and an arbitrary grinding wheel shape can be easily obtained. With the above-mentioned finished dress, the grindstone is dressed in the final shape of the grindstone 17 for forming a groove in the work W.

Next, a drive system of the dressing apparatus 1 for a grinding machine and an operation procedure thereof will be described. FIG. 7 is a block diagram showing a schematic configuration of a drive system of the dressing device for a grinding machine. FIG.
As shown in (1), a command value indicating the position of the work W in the Y-axis direction is sent from the NC program device 51 to the Y-axis servo mechanism 53 of the grinding wheel cutting table 11. The Y-axis servo mechanism 53 receives a displacement feedback signal from a Y-axis displacement detector 55 such as a linear scale for detecting the current position of the grinding wheel cutting table 11. Thereby, the Y of the grindstone 17 with respect to the rotary dress 21 and the NC dress 23
Direction positioning is performed.

A command value indicating the position of the work W in the X-axis direction is sent from the NC program device 51 to the feed table 7.
To the X-axis servo mechanism 57. X-axis servo mechanism 57
, A displacement feedback signal from an X-axis displacement detector 59 for detecting the current position of the feed table 7 is added. Thereby, the rotary dress 21 and the NC dress 2
Positioning of the grindstone 17 with respect to the X-direction 3 is performed.

Further, from the NC program device 51, a turning command value indicating the turning position of the dressing tool 35 in the ψ direction is sent to the ψ turning servo mechanism 61 of the turning motor 43.
The rotation servo mechanism 61 receives a displacement feedback signal from a rotation detector 63 such as an encoder that detects the current position of the single-stone dress tool 35. Thereby, the positioning of the grindstone 17 in the ψ direction with respect to the single-stone dress tool 35 is performed. In addition, a rotation command for rotating the rotary wheel 25 is sent from the NC program device 51 in synchronization with the start of the dressing of the rotary dress 21.

A dressing operation of a grindstone by the dressing apparatus for a grinding machine described above will be described with reference to a flowchart shown in FIG. First, rotary wheel 25, NC dress 2
3 is input to the NC program device 51, the feed table 7 moves in the X direction,
1 moves in the Y direction, and the groove 27 of the rotary dress 21 is moved.
The dressed surface of the grindstone 17 is positioned at the position a (step 1, hereinafter referred to as S1). Thereafter, a rotation command is sent to the rotary wheel 25, the rotary wheel 25 is rotated (S2), and a rough dressing of the grindstone 17 is performed according to the shape of the groove 27a of the rotary wheel 25 while cutting is performed by the grindstone cutting table 11. At this time, the grindstone 17 is driven to rotate by the grindstone spindle 15. This dressing operation is controlled by monitoring the position of the cutting table 11 in the Y direction. After completion of the rough dressing by the groove 27a, similarly, the grindstone 17 is sequentially positioned in the groove 27b and the groove 27c of the rotary wheel 25, and the grindstone 1 is formed by these groove shapes.
7 is performed (S3, S4).

When the rough dressing with all the grooves of the rotary wheel 25 is completed in this way, the NC program device 51 sends a movement command to the feed table 7 and the grindstone cutting table 11, and the position of the diamond 33 in the NC dress 23 is changed. The grindstone 17 is positioned (S5).

Then, the NC program device 51 sends a movement command to the feed table 7, the grindstone cutting table 11, and the turning motor 43. By this movement command, single stone dress tool 3
5 is rotated relatively to the grindstone 17 around the virtual center 71 as shown in FIG. 5 by the rotation of the shaft 39, the movement of the feed table 7, and the movement of the grindstone cutting table 11. (S6). At this time, the grindstone 17 is rotationally driven by the grindstone spindle 15. In this step, the dressing for the grindstone 17 is performed, and the grindstone is dressed in a desired shape. With the above steps, the entire dressing operation is completed, and the process proceeds to preparation for processing the work W by the grindstone 17.

[0030]

As described above, in the dressing machine for a grinder according to the present invention, a rotary dress having a circumferential groove for dress is used as a rough dress having a large amount of dress, and a final dress to be finished in a final whetstone shape is used. An NC dress that allows a single-stone dress tool to operate programmably is used.

In the rotary dress, a rough dress requiring a large amount of grindstone formation can be performed at a stretch, and the amount of dress in each groove can be reduced by providing a plurality of grooves in the grindstone, thereby reducing the amount of wear of the groove. And the life can be prolonged. In the finished dress, by operating a single stone dressing tool on the grindstone after the rough dressing, the grindstone shape can be finished to a desired shape with high accuracy.

As described above, according to the dressing apparatus for a grinding machine according to the present invention, by complementing the disadvantages of the rotary dress and the NC dress, the dressing can be performed in a short time and with high accuracy. Work such as changing the set and the like can be made more efficient, and the dress work can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is a plan view of a male screw grinder provided with a dresser for a grinder according to the present invention.

FIG. 2 is an enlarged view of a main part of a rotary wheel of a rotary dress.

FIG. 3 is a partially enlarged view of FIG. 2;

FIG. 4 is a view taken in the direction of arrows AA in FIG. 1;

FIG. 5 is an explanatory diagram showing a relative turning operation of the single-stone dress tool.

FIG. 6 is an enlarged view of a peripheral portion of a grindstone dressed by a rotary dress.

FIG. 7 is a block diagram showing a schematic configuration of a drive system of the dressing device for a grinding machine according to the present invention.

FIG. 8 is a flowchart showing a main operation of the dressing device for a grinding machine according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dressing device for grinding machines 3 Spindle 7 Feeding table 9 Bed 11 Grinding wheel cutting table 15 Grinding stone spindle 13a Drive shaft 17 Grinding stone 21 Rotary dress 23 NC dress 25 Rotary wheel 31 Handle part 33 Diamond 35 Single stone dressing tool 39 ψ Rotating shaft W work

Claims (1)

[Claims] A feed table movable in an axial direction of a main shaft for rotationally driving a work; a grindstone cutting table movable in a direction orthogonal to an axial direction of the main shaft; A grinding wheel spindle for rotating and driving a disk-shaped grinding wheel mounted on the axis direction as a rotation axis; and a rotary wheel provided on the feed table side and having at least one row of dressing circumferential grooves formed on an outer peripheral surface thereof. A rotary dress that is rotated around an axis parallel to the axis of the grindstone to coarsely dress the peripheral portion of the grindstone; and a single stone dressing tool provided on the feed table side and having a sharpened tip portion. An NC dress that finishes and dresses the peripheral portion of the whetstone while holding it so as to be tiltable about an axis perpendicular to the axis, and an NC program that controls the operation of dressing the whetstone Grinding dresses apparatus characterized by being configured comprises a location, a.